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Overview
Comment:Pull in all the latest changes from the trunk. Update the win32 SHM methods to work with the new interface design.
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Timelines: family | ancestors | descendants | both | wal-win32
Files: files | file ages | folders
SHA1: 4b69f2cd315b6b66d10e5190d235114788853258
User & Date: drh 2010-05-14 16:34:35.000
Original Comment: Pull in all the latest changes from the trunk. Update the win32 SHM methods to work with the new interface design.
Context
2010-05-19
23:41
Merge WIN32 WAL support into trunk. Still some issues with locking to resolve. (check-in: 43377663fc user: shaneh tags: trunk)
2010-05-14
16:34
Pull in all the latest changes from the trunk. Update the win32 SHM methods to work with the new interface design. (Closed-Leaf check-in: 4b69f2cd31 user: drh tags: wal-win32)
14:52
Simplifications to the SHM implementation in os_unix.c, taking advantage of the removal of the LinuxThreads mess. (check-in: d1debe5def user: drh tags: trunk)
2010-05-12
17:14
Updates to WAL support in os_win.c: pulled in latest changes from src/os_unix.c; updated tracing; misc. improvements. (check-in: 76504726a1 user: shaneh tags: wal-win32)
Changes
Unified Diff Ignore Whitespace Patch
Changes to doc/vfs-shm.txt.
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The SQLite core will obey the next set of rules.  These rules are
assertions on the behavior of the SQLite core which might be verified
during testing using an instrumented lock manager.

(5)  No part of the wal-index will be read without holding either some
     kind of SHM lock or an EXCLUSIVE lock on the original database.



(6)  A holder of a READ_FULL will never read any page of the database
     file that is contained anywhere in the wal-index.

(7)  No part of the wal-index other than the header will be written nor
     will the size of the wal-index grow without holding a WRITE.


(8)  The wal-index header will not be written without holding one of
     WRITE, CHECKPOINT, or RECOVER.


(9)  A CHECKPOINT or RECOVER must be held in order to reset the last valid

     frame counter in the header of the wal-index back to zero.

(10) A WRITE can only increase the last valid frame pointer in the header.

The SQLite core will only ever send requests for UNLOCK, READ, WRITE,
CHECKPOINT, or RECOVER to the lock manager.   The SQLite core will never
request a READ_FULL or PENDING lock though the lock manager may deliver
those locking states in response to READ and CHECKPOINT requests,
respectively, if and only if the requested READ or CHECKPOINT cannot







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The SQLite core will obey the next set of rules.  These rules are
assertions on the behavior of the SQLite core which might be verified
during testing using an instrumented lock manager.

(5)  No part of the wal-index will be read without holding either some
     kind of SHM lock or an EXCLUSIVE lock on the original database.
     The original database is the file named in the 2nd parameter to
     the xShmOpen method.

(6)  A holder of a READ_FULL will never read any page of the database
     file that is contained anywhere in the wal-index.

(7)  No part of the wal-index other than the header will be written nor
     will the size of the wal-index grow without holding a WRITE or
     an EXCLUSIVE on the original database file.

(8)  The wal-index header will not be written without holding one of
     WRITE, CHECKPOINT, or RECOVER on the wal-index or an EXCLUSIVE on
     the original database files.

(9)  A CHECKPOINT or RECOVER must be held on the wal-index, or an
     EXCLUSIVE on the original database file, in order to reset the 
     last valid frame counter in the header of the wal-index back to zero.

(10) A WRITE can only increase the last valid frame pointer in the header.

The SQLite core will only ever send requests for UNLOCK, READ, WRITE,
CHECKPOINT, or RECOVER to the lock manager.   The SQLite core will never
request a READ_FULL or PENDING lock though the lock manager may deliver
those locking states in response to READ and CHECKPOINT requests,
respectively, if and only if the requested READ or CHECKPOINT cannot
Changes to src/expr.c.
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      assert( z[n]=='\'' );
      zBlob = sqlite3HexToBlob(sqlite3VdbeDb(v), z, n);
      sqlite3VdbeAddOp4(v, OP_Blob, n/2, target, 0, zBlob, P4_DYNAMIC);
      break;
    }
#endif
    case TK_VARIABLE: {
      VdbeOp *pOp;
      assert( !ExprHasProperty(pExpr, EP_IntValue) );
      assert( pExpr->u.zToken!=0 );
      assert( pExpr->u.zToken[0]!=0 );
      if( pExpr->u.zToken[1]==0
         && (pOp = sqlite3VdbeGetOp(v, -1))->opcode==OP_Variable
         && pOp->p1+pOp->p3==pExpr->iColumn
         && pOp->p2+pOp->p3==target
         && pOp->p4.z==0
      ){
        /* If the previous instruction was a copy of the previous unnamed
        ** parameter into the previous register, then simply increment the
        ** repeat count on the prior instruction rather than making a new
        ** instruction.
        */
        pOp->p3++;
      }else{
        sqlite3VdbeAddOp3(v, OP_Variable, pExpr->iColumn, target, 1);
        if( pExpr->u.zToken[1]!=0 ){
          sqlite3VdbeChangeP4(v, -1, pExpr->u.zToken, 0);
        }
      }
      break;
    }
    case TK_REGISTER: {
      inReg = pExpr->iTable;
      break;
    }







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      assert( z[n]=='\'' );
      zBlob = sqlite3HexToBlob(sqlite3VdbeDb(v), z, n);
      sqlite3VdbeAddOp4(v, OP_Blob, n/2, target, 0, zBlob, P4_DYNAMIC);
      break;
    }
#endif
    case TK_VARIABLE: {

      assert( !ExprHasProperty(pExpr, EP_IntValue) );
      assert( pExpr->u.zToken!=0 );
      assert( pExpr->u.zToken[0]!=0 );













      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iColumn, target);
      if( pExpr->u.zToken[1]!=0 ){
        sqlite3VdbeChangeP4(v, -1, pExpr->u.zToken, 0);

      }
      break;
    }
    case TK_REGISTER: {
      inReg = pExpr->iTable;
      break;
    }
Changes to src/mutex_unix.c.
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** Note that this implementation requires a version of pthreads that
** supports recursive mutexes.
*/
#ifdef SQLITE_MUTEX_PTHREADS

#include <pthread.h>












/*
** Each recursive mutex is an instance of the following structure.
*/
struct sqlite3_mutex {
  pthread_mutex_t mutex;     /* Mutex controlling the lock */

  int id;                    /* Mutex type */
  int nRef;                  /* Number of entrances */
  pthread_t owner;           /* Thread that is within this mutex */
#ifdef SQLITE_DEBUG
  int trace;                 /* True to trace changes */
#endif
};
#ifdef SQLITE_DEBUG
#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, 0, 0, (pthread_t)0, 0 }
#else
#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, 0, 0, (pthread_t)0 }
#endif

/*
** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
** intended for use only inside assert() statements.  On some platforms,
** there might be race conditions that can cause these routines to
** deliver incorrect results.  In particular, if pthread_equal() is







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** Note that this implementation requires a version of pthreads that
** supports recursive mutexes.
*/
#ifdef SQLITE_MUTEX_PTHREADS

#include <pthread.h>

/*
** The sqlite3_mutex.id, sqlite3_mutex.nRef, and sqlite3_mutex.owner fields
** are necessary under two condidtions:  (1) Debug builds and (2) using
** home-grown mutexes.  Encapsulate these conditions into a single #define.
*/
#if defined(SQLITE_DEBUG) || defined(SQLITE_HOMEGROWN_RECURSIVE_MUTEX)
# define SQLITE_MUTEX_NREF 1
#else
# define SQLITE_MUTEX_NREF 0
#endif

/*
** Each recursive mutex is an instance of the following structure.
*/
struct sqlite3_mutex {
  pthread_mutex_t mutex;     /* Mutex controlling the lock */
#if SQLITE_MUTEX_NREF
  int id;                    /* Mutex type */
  volatile int nRef;         /* Number of entrances */
  volatile pthread_t owner;  /* Thread that is within this mutex */

  int trace;                 /* True to trace changes */
#endif
};
#if SQLITE_MUTEX_NREF
#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, 0, 0, (pthread_t)0, 0 }
#else
#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER }
#endif

/*
** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
** intended for use only inside assert() statements.  On some platforms,
** there might be race conditions that can cause these routines to
** deliver incorrect results.  In particular, if pthread_equal() is
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        /* Use a recursive mutex if it is available */
        pthread_mutexattr_t recursiveAttr;
        pthread_mutexattr_init(&recursiveAttr);
        pthread_mutexattr_settype(&recursiveAttr, PTHREAD_MUTEX_RECURSIVE);
        pthread_mutex_init(&p->mutex, &recursiveAttr);
        pthread_mutexattr_destroy(&recursiveAttr);
#endif

        p->id = iType;

      }
      break;
    }
    case SQLITE_MUTEX_FAST: {
      p = sqlite3MallocZero( sizeof(*p) );
      if( p ){

        p->id = iType;

        pthread_mutex_init(&p->mutex, 0);
      }
      break;
    }
    default: {
      assert( iType-2 >= 0 );
      assert( iType-2 < ArraySize(staticMutexes) );
      p = &staticMutexes[iType-2];

      p->id = iType;

      break;
    }
  }
  return p;
}









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        /* Use a recursive mutex if it is available */
        pthread_mutexattr_t recursiveAttr;
        pthread_mutexattr_init(&recursiveAttr);
        pthread_mutexattr_settype(&recursiveAttr, PTHREAD_MUTEX_RECURSIVE);
        pthread_mutex_init(&p->mutex, &recursiveAttr);
        pthread_mutexattr_destroy(&recursiveAttr);
#endif
#if SQLITE_MUTEX_NREF
        p->id = iType;
#endif
      }
      break;
    }
    case SQLITE_MUTEX_FAST: {
      p = sqlite3MallocZero( sizeof(*p) );
      if( p ){
#if SQLITE_MUTEX_NREF
        p->id = iType;
#endif
        pthread_mutex_init(&p->mutex, 0);
      }
      break;
    }
    default: {
      assert( iType-2 >= 0 );
      assert( iType-2 < ArraySize(staticMutexes) );
      p = &staticMutexes[iType-2];
#if SQLITE_MUTEX_NREF
      p->id = iType;
#endif
      break;
    }
  }
  return p;
}


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      p->nRef = 1;
    }
  }
#else
  /* Use the built-in recursive mutexes if they are available.
  */
  pthread_mutex_lock(&p->mutex);

  p->owner = pthread_self();
  p->nRef++;

#endif

#ifdef SQLITE_DEBUG
  if( p->trace ){
    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
  }
#endif







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      p->nRef = 1;
    }
  }
#else
  /* Use the built-in recursive mutexes if they are available.
  */
  pthread_mutex_lock(&p->mutex);
#if SQLITE_MUTEX_NREF
  p->owner = pthread_self();
  p->nRef++;
#endif
#endif

#ifdef SQLITE_DEBUG
  if( p->trace ){
    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
  }
#endif
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      rc = SQLITE_BUSY;
    }
  }
#else
  /* Use the built-in recursive mutexes if they are available.
  */
  if( pthread_mutex_trylock(&p->mutex)==0 ){

    p->owner = pthread_self();
    p->nRef++;

    rc = SQLITE_OK;
  }else{
    rc = SQLITE_BUSY;
  }
#endif

#ifdef SQLITE_DEBUG







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      rc = SQLITE_BUSY;
    }
  }
#else
  /* Use the built-in recursive mutexes if they are available.
  */
  if( pthread_mutex_trylock(&p->mutex)==0 ){
#if SQLITE_MUTEX_NREF
    p->owner = pthread_self();
    p->nRef++;
#endif
    rc = SQLITE_OK;
  }else{
    rc = SQLITE_BUSY;
  }
#endif

#ifdef SQLITE_DEBUG
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** The sqlite3_mutex_leave() routine exits a mutex that was
** previously entered by the same thread.  The behavior
** is undefined if the mutex is not currently entered or
** is not currently allocated.  SQLite will never do either.
*/
static void pthreadMutexLeave(sqlite3_mutex *p){
  assert( pthreadMutexHeld(p) );

  p->nRef--;

  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );

#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
  if( p->nRef==0 ){
    pthread_mutex_unlock(&p->mutex);
  }
#else







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** The sqlite3_mutex_leave() routine exits a mutex that was
** previously entered by the same thread.  The behavior
** is undefined if the mutex is not currently entered or
** is not currently allocated.  SQLite will never do either.
*/
static void pthreadMutexLeave(sqlite3_mutex *p){
  assert( pthreadMutexHeld(p) );
#if SQLITE_MUTEX_NREF
  p->nRef--;
#endif
  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );

#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
  if( p->nRef==0 ){
    pthread_mutex_unlock(&p->mutex);
  }
#else
Changes to src/mutex_w32.c.
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/*
** Each recursive mutex is an instance of the following structure.
*/
struct sqlite3_mutex {
  CRITICAL_SECTION mutex;    /* Mutex controlling the lock */
  int id;                    /* Mutex type */
  int nRef;                  /* Number of enterances */
  DWORD owner;               /* Thread holding this mutex */
#ifdef SQLITE_DEBUG


  int trace;                 /* True to trace changes */
#endif
};
#define SQLITE_W32_MUTEX_INITIALIZER { 0 }
#ifdef SQLITE_DEBUG
#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0, 0L, (DWORD)0, 0 }
#else
#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0, 0L, (DWORD)0 }
#endif

/*
** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
**
** Here is an interesting observation:  Win95, Win98, and WinME lack







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/*
** Each recursive mutex is an instance of the following structure.
*/
struct sqlite3_mutex {
  CRITICAL_SECTION mutex;    /* Mutex controlling the lock */
  int id;                    /* Mutex type */


#ifdef SQLITE_DEBUG
  volatile int nRef;         /* Number of enterances */
  volatile DWORD owner;      /* Thread holding this mutex */
  int trace;                 /* True to trace changes */
#endif
};
#define SQLITE_W32_MUTEX_INITIALIZER { 0 }
#ifdef SQLITE_DEBUG
#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0, 0L, (DWORD)0, 0 }
#else
#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0 }
#endif

/*
** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
**
** Here is an interesting observation:  Win95, Win98, and WinME lack
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  sqlite3_mutex *p;

  switch( iType ){
    case SQLITE_MUTEX_FAST:
    case SQLITE_MUTEX_RECURSIVE: {
      p = sqlite3MallocZero( sizeof(*p) );
      if( p ){  

        p->id = iType;

        InitializeCriticalSection(&p->mutex);
      }
      break;
    }
    default: {
      assert( winMutex_isInit==1 );
      assert( iType-2 >= 0 );
      assert( iType-2 < ArraySize(winMutex_staticMutexes) );
      p = &winMutex_staticMutexes[iType-2];

      p->id = iType;

      break;
    }
  }
  return p;
}









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  sqlite3_mutex *p;

  switch( iType ){
    case SQLITE_MUTEX_FAST:
    case SQLITE_MUTEX_RECURSIVE: {
      p = sqlite3MallocZero( sizeof(*p) );
      if( p ){  
#ifdef SQLITE_DEBUG
        p->id = iType;
#endif
        InitializeCriticalSection(&p->mutex);
      }
      break;
    }
    default: {
      assert( winMutex_isInit==1 );
      assert( iType-2 >= 0 );
      assert( iType-2 < ArraySize(winMutex_staticMutexes) );
      p = &winMutex_staticMutexes[iType-2];
#ifdef SQLITE_DEBUG
      p->id = iType;
#endif
      break;
    }
  }
  return p;
}


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** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
** be entered multiple times by the same thread.  In such cases the,
** mutex must be exited an equal number of times before another thread
** can enter.  If the same thread tries to enter any other kind of mutex
** more than once, the behavior is undefined.
*/
static void winMutexEnter(sqlite3_mutex *p){

  DWORD tid = GetCurrentThreadId(); 
  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );

  EnterCriticalSection(&p->mutex);

  p->owner = tid; 
  p->nRef++;
#ifdef SQLITE_DEBUG
  if( p->trace ){
    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
  }
#endif
}
static int winMutexTry(sqlite3_mutex *p){
#ifndef NDEBUG







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** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
** be entered multiple times by the same thread.  In such cases the,
** mutex must be exited an equal number of times before another thread
** can enter.  If the same thread tries to enter any other kind of mutex
** more than once, the behavior is undefined.
*/
static void winMutexEnter(sqlite3_mutex *p){
#ifdef SQLITE_DEBUG
  DWORD tid = GetCurrentThreadId(); 
  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
#endif
  EnterCriticalSection(&p->mutex);
#ifdef SQLITE_DEBUG
  p->owner = tid; 
  p->nRef++;

  if( p->trace ){
    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
  }
#endif
}
static int winMutexTry(sqlite3_mutex *p){
#ifndef NDEBUG
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** previously entered by the same thread.  The behavior
** is undefined if the mutex is not currently entered or
** is not currently allocated.  SQLite will never do either.
*/
static void winMutexLeave(sqlite3_mutex *p){
#ifndef NDEBUG
  DWORD tid = GetCurrentThreadId();
#endif
  assert( p->nRef>0 );
  assert( p->owner==tid );
  p->nRef--;
  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );

  LeaveCriticalSection(&p->mutex);
#ifdef SQLITE_DEBUG
  if( p->trace ){
    printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
  }
#endif
}







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** previously entered by the same thread.  The behavior
** is undefined if the mutex is not currently entered or
** is not currently allocated.  SQLite will never do either.
*/
static void winMutexLeave(sqlite3_mutex *p){
#ifndef NDEBUG
  DWORD tid = GetCurrentThreadId();

  assert( p->nRef>0 );
  assert( p->owner==tid );
  p->nRef--;
  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
#endif
  LeaveCriticalSection(&p->mutex);
#ifdef SQLITE_DEBUG
  if( p->trace ){
    printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
  }
#endif
}
Changes to src/os.c.
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int sqlite3OsSectorSize(sqlite3_file *id){
  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
}
int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
  return id->pMethods->xDeviceCharacteristics(id);
}



















/*
** The next group of routines are convenience wrappers around the
** VFS methods.
*/
int sqlite3OsOpen(
  sqlite3_vfs *pVfs, 







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int sqlite3OsSectorSize(sqlite3_file *id){
  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
}
int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
  return id->pMethods->xDeviceCharacteristics(id);
}
int sqlite3OsShmOpen(sqlite3_file *id){
  return id->pMethods->xShmOpen(id);
}
int sqlite3OsShmSize(sqlite3_file *id, int reqSize, int *pNewSize){
  return id->pMethods->xShmSize(id, reqSize, pNewSize);
}
int sqlite3OsShmGet(sqlite3_file *id, int reqSize, int *pSize, void **pp){
  return id->pMethods->xShmGet(id, reqSize, pSize, pp);
}
int sqlite3OsShmRelease(sqlite3_file *id){
  return id->pMethods->xShmRelease(id);
}
int sqlite3OsShmLock(sqlite3_file *id, int desiredLock, int *pGotLock){
  return id->pMethods->xShmLock(id, desiredLock, pGotLock);
}
int sqlite3OsShmClose(sqlite3_file *id, int deleteFlag){
  return id->pMethods->xShmClose(id, deleteFlag);
}

/*
** The next group of routines are convenience wrappers around the
** VFS methods.
*/
int sqlite3OsOpen(
  sqlite3_vfs *pVfs, 
Changes to src/os.h.
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int sqlite3OsLock(sqlite3_file*, int);
int sqlite3OsUnlock(sqlite3_file*, int);
int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut);
int sqlite3OsFileControl(sqlite3_file*,int,void*);
#define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0
int sqlite3OsSectorSize(sqlite3_file *id);
int sqlite3OsDeviceCharacteristics(sqlite3_file *id);







/* 
** Functions for accessing sqlite3_vfs methods 
*/
int sqlite3OsOpen(sqlite3_vfs *, const char *, sqlite3_file*, int, int *);
int sqlite3OsDelete(sqlite3_vfs *, const char *, int);
int sqlite3OsAccess(sqlite3_vfs *, const char *, int, int *pResOut);







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int sqlite3OsLock(sqlite3_file*, int);
int sqlite3OsUnlock(sqlite3_file*, int);
int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut);
int sqlite3OsFileControl(sqlite3_file*,int,void*);
#define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0
int sqlite3OsSectorSize(sqlite3_file *id);
int sqlite3OsDeviceCharacteristics(sqlite3_file *id);
int sqlite3OsShmOpen(sqlite3_file *id);
int sqlite3OsShmSize(sqlite3_file *id, int, int*);
int sqlite3OsShmGet(sqlite3_file *id, int, int*, void**);
int sqlite3OsShmRelease(sqlite3_file *id);
int sqlite3OsShmLock(sqlite3_file *id, int, int*);
int sqlite3OsShmClose(sqlite3_file *id, int);

/* 
** Functions for accessing sqlite3_vfs methods 
*/
int sqlite3OsOpen(sqlite3_vfs *, const char *, sqlite3_file*, int, int *);
int sqlite3OsDelete(sqlite3_vfs *, const char *, int);
int sqlite3OsAccess(sqlite3_vfs *, const char *, int, int *pResOut);
Changes to src/os_common.h.
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*/
#ifdef MEMORY_DEBUG
# error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
#endif

#ifdef SQLITE_DEBUG
int sqlite3OSTrace = 0;
#define OSTRACE1(X)         if( sqlite3OSTrace ) sqlite3DebugPrintf(X)
#define OSTRACE2(X,Y)       if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y)
#define OSTRACE3(X,Y,Z)     if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z)
#define OSTRACE4(X,Y,Z,A)   if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A)
#define OSTRACE5(X,Y,Z,A,B) if( sqlite3OSTrace ) sqlite3DebugPrintf(X,Y,Z,A,B)
#define OSTRACE6(X,Y,Z,A,B,C) \
    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C)
#define OSTRACE7(X,Y,Z,A,B,C,D) \
    if(sqlite3OSTrace) sqlite3DebugPrintf(X,Y,Z,A,B,C,D)
#define OSTRACE(X)          if( sqlite3OSTrace ) sqlite3DebugPrintf X
#else
#define OSTRACE1(X)
#define OSTRACE2(X,Y)
#define OSTRACE3(X,Y,Z)
#define OSTRACE4(X,Y,Z,A)
#define OSTRACE5(X,Y,Z,A,B)
#define OSTRACE6(X,Y,Z,A,B,C)
#define OSTRACE7(X,Y,Z,A,B,C,D)
#define OSTRACE(X)
#endif

/*
** Macros for performance tracing.  Normally turned off.  Only works
** on i486 hardware.
*/







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*/
#ifdef MEMORY_DEBUG
# error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
#endif

#ifdef SQLITE_DEBUG
int sqlite3OSTrace = 0;









#define OSTRACE(X)          if( sqlite3OSTrace ) sqlite3DebugPrintf X
#else







#define OSTRACE(X)
#endif

/*
** Macros for performance tracing.  Normally turned off.  Only works
** on i486 hardware.
*/
Changes to src/os_os2.c.
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/*
** Close a file.
*/
static int os2Close( sqlite3_file *id ){
  APIRET rc = NO_ERROR;
  os2File *pFile;
  if( id && (pFile = (os2File*)id) != 0 ){
    OSTRACE2( "CLOSE %d\n", pFile->h );
    rc = DosClose( pFile->h );
    pFile->locktype = NO_LOCK;
    if( pFile->pathToDel != NULL ){
      rc = DosForceDelete( (PSZ)pFile->pathToDel );
      free( pFile->pathToDel );
      pFile->pathToDel = NULL;
    }







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/*
** Close a file.
*/
static int os2Close( sqlite3_file *id ){
  APIRET rc = NO_ERROR;
  os2File *pFile;
  if( id && (pFile = (os2File*)id) != 0 ){
    OSTRACE(( "CLOSE %d\n", pFile->h ));
    rc = DosClose( pFile->h );
    pFile->locktype = NO_LOCK;
    if( pFile->pathToDel != NULL ){
      rc = DosForceDelete( (PSZ)pFile->pathToDel );
      free( pFile->pathToDel );
      pFile->pathToDel = NULL;
    }
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  sqlite3_int64 offset            /* Begin reading at this offset */
){
  ULONG fileLocation = 0L;
  ULONG got;
  os2File *pFile = (os2File*)id;
  assert( id!=0 );
  SimulateIOError( return SQLITE_IOERR_READ );
  OSTRACE3( "READ %d lock=%d\n", pFile->h, pFile->locktype );
  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
    return SQLITE_IOERR;
  }
  if( DosRead( pFile->h, pBuf, amt, &got ) != NO_ERROR ){
    return SQLITE_IOERR_READ;
  }
  if( got == (ULONG)amt )







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  sqlite3_int64 offset            /* Begin reading at this offset */
){
  ULONG fileLocation = 0L;
  ULONG got;
  os2File *pFile = (os2File*)id;
  assert( id!=0 );
  SimulateIOError( return SQLITE_IOERR_READ );
  OSTRACE(( "READ %d lock=%d\n", pFile->h, pFile->locktype ));
  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
    return SQLITE_IOERR;
  }
  if( DosRead( pFile->h, pBuf, amt, &got ) != NO_ERROR ){
    return SQLITE_IOERR_READ;
  }
  if( got == (ULONG)amt )
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  ULONG fileLocation = 0L;
  APIRET rc = NO_ERROR;
  ULONG wrote;
  os2File *pFile = (os2File*)id;
  assert( id!=0 );
  SimulateIOError( return SQLITE_IOERR_WRITE );
  SimulateDiskfullError( return SQLITE_FULL );
  OSTRACE3( "WRITE %d lock=%d\n", pFile->h, pFile->locktype );
  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
    return SQLITE_IOERR;
  }
  assert( amt>0 );
  while( amt > 0 &&
         ( rc = DosWrite( pFile->h, (PVOID)pBuf, amt, &wrote ) ) == NO_ERROR &&
         wrote > 0







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  ULONG fileLocation = 0L;
  APIRET rc = NO_ERROR;
  ULONG wrote;
  os2File *pFile = (os2File*)id;
  assert( id!=0 );
  SimulateIOError( return SQLITE_IOERR_WRITE );
  SimulateDiskfullError( return SQLITE_FULL );
  OSTRACE(( "WRITE %d lock=%d\n", pFile->h, pFile->locktype ));
  if( DosSetFilePtr(pFile->h, offset, FILE_BEGIN, &fileLocation) != NO_ERROR ){
    return SQLITE_IOERR;
  }
  assert( amt>0 );
  while( amt > 0 &&
         ( rc = DosWrite( pFile->h, (PVOID)pBuf, amt, &wrote ) ) == NO_ERROR &&
         wrote > 0
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/*
** Truncate an open file to a specified size
*/
static int os2Truncate( sqlite3_file *id, i64 nByte ){
  APIRET rc = NO_ERROR;
  os2File *pFile = (os2File*)id;
  OSTRACE3( "TRUNCATE %d %lld\n", pFile->h, nByte );
  SimulateIOError( return SQLITE_IOERR_TRUNCATE );
  rc = DosSetFileSize( pFile->h, nByte );
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR_TRUNCATE;
}

#ifdef SQLITE_TEST
/*
** Count the number of fullsyncs and normal syncs.  This is used to test
** that syncs and fullsyncs are occuring at the right times.
*/
int sqlite3_sync_count = 0;
int sqlite3_fullsync_count = 0;
#endif

/*
** Make sure all writes to a particular file are committed to disk.
*/
static int os2Sync( sqlite3_file *id, int flags ){
  os2File *pFile = (os2File*)id;
  OSTRACE3( "SYNC %d lock=%d\n", pFile->h, pFile->locktype );
#ifdef SQLITE_TEST
  if( flags & SQLITE_SYNC_FULL){
    sqlite3_fullsync_count++;
  }
  sqlite3_sync_count++;
#endif
  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a







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/*
** Truncate an open file to a specified size
*/
static int os2Truncate( sqlite3_file *id, i64 nByte ){
  APIRET rc = NO_ERROR;
  os2File *pFile = (os2File*)id;
  OSTRACE(( "TRUNCATE %d %lld\n", pFile->h, nByte ));
  SimulateIOError( return SQLITE_IOERR_TRUNCATE );
  rc = DosSetFileSize( pFile->h, nByte );
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR_TRUNCATE;
}

#ifdef SQLITE_TEST
/*
** Count the number of fullsyncs and normal syncs.  This is used to test
** that syncs and fullsyncs are occuring at the right times.
*/
int sqlite3_sync_count = 0;
int sqlite3_fullsync_count = 0;
#endif

/*
** Make sure all writes to a particular file are committed to disk.
*/
static int os2Sync( sqlite3_file *id, int flags ){
  os2File *pFile = (os2File*)id;
  OSTRACE(( "SYNC %d lock=%d\n", pFile->h, pFile->locktype ));
#ifdef SQLITE_TEST
  if( flags & SQLITE_SYNC_FULL){
    sqlite3_fullsync_count++;
  }
  sqlite3_sync_count++;
#endif
  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
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  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  LockArea.lOffset = SHARED_FIRST;
  LockArea.lRange = SHARED_SIZE;
  UnlockArea.lOffset = 0L;
  UnlockArea.lRange = 0L;
  res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
  OSTRACE3( "GETREADLOCK %d res=%d\n", pFile->h, res );
  return res;
}

/*
** Undo a readlock
*/
static int unlockReadLock( os2File *id ){
  FILELOCK  LockArea,
            UnlockArea;
  APIRET res;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  LockArea.lOffset = 0L;
  LockArea.lRange = 0L;
  UnlockArea.lOffset = SHARED_FIRST;
  UnlockArea.lRange = SHARED_SIZE;
  res = DosSetFileLocks( id->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
  OSTRACE3( "UNLOCK-READLOCK file handle=%d res=%d?\n", id->h, res );
  return res;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**







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  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  LockArea.lOffset = SHARED_FIRST;
  LockArea.lRange = SHARED_SIZE;
  UnlockArea.lOffset = 0L;
  UnlockArea.lRange = 0L;
  res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
  OSTRACE(( "GETREADLOCK %d res=%d\n", pFile->h, res ));
  return res;
}

/*
** Undo a readlock
*/
static int unlockReadLock( os2File *id ){
  FILELOCK  LockArea,
            UnlockArea;
  APIRET res;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  LockArea.lOffset = 0L;
  LockArea.lRange = 0L;
  UnlockArea.lOffset = SHARED_FIRST;
  UnlockArea.lRange = SHARED_SIZE;
  res = DosSetFileLocks( id->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 1L );
  OSTRACE(( "UNLOCK-READLOCK file handle=%d res=%d?\n", id->h, res ));
  return res;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**
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  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
  FILELOCK  LockArea,
            UnlockArea;
  os2File *pFile = (os2File*)id;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  assert( pFile!=0 );
  OSTRACE4( "LOCK %d %d was %d\n", pFile->h, locktype, pFile->locktype );

  /* If there is already a lock of this type or more restrictive on the
  ** os2File, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3_mutex_enter() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){
    OSTRACE3( "LOCK %d %d ok (already held)\n", pFile->h, locktype );
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct
  */
  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
  assert( locktype!=PENDING_LOCK );







|






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  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
  FILELOCK  LockArea,
            UnlockArea;
  os2File *pFile = (os2File*)id;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  assert( pFile!=0 );
  OSTRACE(( "LOCK %d %d was %d\n", pFile->h, locktype, pFile->locktype ));

  /* If there is already a lock of this type or more restrictive on the
  ** os2File, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3_mutex_enter() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){
    OSTRACE(( "LOCK %d %d ok (already held)\n", pFile->h, locktype ));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct
  */
  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
  assert( locktype!=PENDING_LOCK );
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    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;

    /* wait longer than LOCK_TIMEOUT here not to have to try multiple times */
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 100L, 0L );
    if( res == NO_ERROR ){
      gotPendingLock = 1;
      OSTRACE3( "LOCK %d pending lock boolean set.  res=%d\n", pFile->h, res );
    }
  }

  /* Acquire a shared lock
  */
  if( locktype==SHARED_LOCK && res == NO_ERROR ){
    assert( pFile->locktype==NO_LOCK );
    res = getReadLock(pFile);
    if( res == NO_ERROR ){
      newLocktype = SHARED_LOCK;
    }
    OSTRACE3( "LOCK %d acquire shared lock. res=%d\n", pFile->h, res );
  }

  /* Acquire a RESERVED lock
  */
  if( locktype==RESERVED_LOCK && res == NO_ERROR ){
    assert( pFile->locktype==SHARED_LOCK );
    LockArea.lOffset = RESERVED_BYTE;
    LockArea.lRange = 1L;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    if( res == NO_ERROR ){
      newLocktype = RESERVED_LOCK;
    }
    OSTRACE3( "LOCK %d acquire reserved lock. res=%d\n", pFile->h, res );
  }

  /* Acquire a PENDING lock
  */
  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
    newLocktype = PENDING_LOCK;
    gotPendingLock = 0;
    OSTRACE2( "LOCK %d acquire pending lock. pending lock boolean unset.\n", pFile->h );

  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
    assert( pFile->locktype>=SHARED_LOCK );
    res = unlockReadLock(pFile);
    OSTRACE2( "unreadlock = %d\n", res );
    LockArea.lOffset = SHARED_FIRST;
    LockArea.lRange = SHARED_SIZE;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    if( res == NO_ERROR ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      OSTRACE2( "OS/2 error-code = %d\n", res );
      getReadLock(pFile);
    }
    OSTRACE3( "LOCK %d acquire exclusive lock.  res=%d\n", pFile->h, res );
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){
    int r;
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = PENDING_BYTE;
    UnlockArea.lRange = 1L;
    r = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE3( "LOCK %d unlocking pending/is shared. r=%d\n", pFile->h, r );
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res == NO_ERROR ){
    rc = SQLITE_OK;
  }else{
    OSTRACE4( "LOCK FAILED %d trying for %d but got %d\n", pFile->h,
              locktype, newLocktype );
    rc = SQLITE_BUSY;
  }
  pFile->locktype = newLocktype;
  OSTRACE3( "LOCK %d now %d\n", pFile->h, pFile->locktype );
  return rc;
}

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, return
** non-zero, otherwise zero.
*/
static int os2CheckReservedLock( sqlite3_file *id, int *pOut ){
  int r = 0;
  os2File *pFile = (os2File*)id;
  assert( pFile!=0 );
  if( pFile->locktype>=RESERVED_LOCK ){
    r = 1;
    OSTRACE3( "TEST WR-LOCK %d %d (local)\n", pFile->h, r );
  }else{
    FILELOCK  LockArea,
              UnlockArea;
    APIRET rc = NO_ERROR;
    memset(&LockArea, 0, sizeof(LockArea));
    memset(&UnlockArea, 0, sizeof(UnlockArea));
    LockArea.lOffset = RESERVED_BYTE;
    LockArea.lRange = 1L;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    rc = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE3( "TEST WR-LOCK %d lock reserved byte rc=%d\n", pFile->h, rc );
    if( rc == NO_ERROR ){
      APIRET rcu = NO_ERROR; /* return code for unlocking */
      LockArea.lOffset = 0L;
      LockArea.lRange = 0L;
      UnlockArea.lOffset = RESERVED_BYTE;
      UnlockArea.lRange = 1L;
      rcu = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
      OSTRACE3( "TEST WR-LOCK %d unlock reserved byte r=%d\n", pFile->h, rcu );
    }
    r = !(rc == NO_ERROR);
    OSTRACE3( "TEST WR-LOCK %d %d (remote)\n", pFile->h, r );
  }
  *pOut = r;
  return SQLITE_OK;
}

/*
** Lower the locking level on file descriptor id to locktype.  locktype







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    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;

    /* wait longer than LOCK_TIMEOUT here not to have to try multiple times */
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 100L, 0L );
    if( res == NO_ERROR ){
      gotPendingLock = 1;
      OSTRACE(( "LOCK %d pending lock boolean set.  res=%d\n", pFile->h, res ));
    }
  }

  /* Acquire a shared lock
  */
  if( locktype==SHARED_LOCK && res == NO_ERROR ){
    assert( pFile->locktype==NO_LOCK );
    res = getReadLock(pFile);
    if( res == NO_ERROR ){
      newLocktype = SHARED_LOCK;
    }
    OSTRACE(( "LOCK %d acquire shared lock. res=%d\n", pFile->h, res ));
  }

  /* Acquire a RESERVED lock
  */
  if( locktype==RESERVED_LOCK && res == NO_ERROR ){
    assert( pFile->locktype==SHARED_LOCK );
    LockArea.lOffset = RESERVED_BYTE;
    LockArea.lRange = 1L;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    if( res == NO_ERROR ){
      newLocktype = RESERVED_LOCK;
    }
    OSTRACE(( "LOCK %d acquire reserved lock. res=%d\n", pFile->h, res ));
  }

  /* Acquire a PENDING lock
  */
  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
    newLocktype = PENDING_LOCK;
    gotPendingLock = 0;
    OSTRACE(( "LOCK %d acquire pending lock. pending lock boolean unset.\n",
               pFile->h ));
  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res == NO_ERROR ){
    assert( pFile->locktype>=SHARED_LOCK );
    res = unlockReadLock(pFile);
    OSTRACE(( "unreadlock = %d\n", res ));
    LockArea.lOffset = SHARED_FIRST;
    LockArea.lRange = SHARED_SIZE;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    if( res == NO_ERROR ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      OSTRACE(( "OS/2 error-code = %d\n", res ));
      getReadLock(pFile);
    }
    OSTRACE(( "LOCK %d acquire exclusive lock.  res=%d\n", pFile->h, res ));
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){
    int r;
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = PENDING_BYTE;
    UnlockArea.lRange = 1L;
    r = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "LOCK %d unlocking pending/is shared. r=%d\n", pFile->h, r ));
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res == NO_ERROR ){
    rc = SQLITE_OK;
  }else{
    OSTRACE(( "LOCK FAILED %d trying for %d but got %d\n", pFile->h,
              locktype, newLocktype ));
    rc = SQLITE_BUSY;
  }
  pFile->locktype = newLocktype;
  OSTRACE(( "LOCK %d now %d\n", pFile->h, pFile->locktype ));
  return rc;
}

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, return
** non-zero, otherwise zero.
*/
static int os2CheckReservedLock( sqlite3_file *id, int *pOut ){
  int r = 0;
  os2File *pFile = (os2File*)id;
  assert( pFile!=0 );
  if( pFile->locktype>=RESERVED_LOCK ){
    r = 1;
    OSTRACE(( "TEST WR-LOCK %d %d (local)\n", pFile->h, r ));
  }else{
    FILELOCK  LockArea,
              UnlockArea;
    APIRET rc = NO_ERROR;
    memset(&LockArea, 0, sizeof(LockArea));
    memset(&UnlockArea, 0, sizeof(UnlockArea));
    LockArea.lOffset = RESERVED_BYTE;
    LockArea.lRange = 1L;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    rc = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "TEST WR-LOCK %d lock reserved byte rc=%d\n", pFile->h, rc ));
    if( rc == NO_ERROR ){
      APIRET rcu = NO_ERROR; /* return code for unlocking */
      LockArea.lOffset = 0L;
      LockArea.lRange = 0L;
      UnlockArea.lOffset = RESERVED_BYTE;
      UnlockArea.lRange = 1L;
      rcu = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
      OSTRACE(( "TEST WR-LOCK %d unlock reserved byte r=%d\n", pFile->h, rcu ));
    }
    r = !(rc == NO_ERROR);
    OSTRACE(( "TEST WR-LOCK %d %d (remote)\n", pFile->h, r ));
  }
  *pOut = r;
  return SQLITE_OK;
}

/*
** Lower the locking level on file descriptor id to locktype.  locktype
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  APIRET res = NO_ERROR;
  FILELOCK  LockArea,
            UnlockArea;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE4( "UNLOCK %d to %d was %d\n", pFile->h, locktype, pFile->locktype );
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = SHARED_FIRST;
    UnlockArea.lRange = SHARED_SIZE;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE3( "UNLOCK %d exclusive lock res=%d\n", pFile->h, res );
    if( locktype==SHARED_LOCK && getReadLock(pFile) != NO_ERROR ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */
      OSTRACE3( "UNLOCK %d to %d getReadLock() failed\n", pFile->h, locktype );
      rc = SQLITE_IOERR_UNLOCK;
    }
  }
  if( type>=RESERVED_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = RESERVED_BYTE;
    UnlockArea.lRange = 1L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE3( "UNLOCK %d reserved res=%d\n", pFile->h, res );
  }
  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
    res = unlockReadLock(pFile);
    OSTRACE5( "UNLOCK %d is %d want %d res=%d\n", pFile->h, type, locktype, res );

  }
  if( type>=PENDING_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = PENDING_BYTE;
    UnlockArea.lRange = 1L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE3( "UNLOCK %d pending res=%d\n", pFile->h, res );
  }
  pFile->locktype = locktype;
  OSTRACE3( "UNLOCK %d now %d\n", pFile->h, pFile->locktype );
  return rc;
}

/*
** Control and query of the open file handle.
*/
static int os2FileControl(sqlite3_file *id, int op, void *pArg){
  switch( op ){
    case SQLITE_FCNTL_LOCKSTATE: {
      *(int*)pArg = ((os2File*)id)->locktype;

      OSTRACE3( "FCNTL_LOCKSTATE %d lock=%d\n", ((os2File*)id)->h, ((os2File*)id)->locktype );
      return SQLITE_OK;
    }
  }
  return SQLITE_ERROR;
}

/*







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  APIRET res = NO_ERROR;
  FILELOCK  LockArea,
            UnlockArea;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE(( "UNLOCK %d to %d was %d\n", pFile->h, locktype, pFile->locktype ));
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = SHARED_FIRST;
    UnlockArea.lRange = SHARED_SIZE;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "UNLOCK %d exclusive lock res=%d\n", pFile->h, res ));
    if( locktype==SHARED_LOCK && getReadLock(pFile) != NO_ERROR ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */
      OSTRACE(( "UNLOCK %d to %d getReadLock() failed\n", pFile->h, locktype ));
      rc = SQLITE_IOERR_UNLOCK;
    }
  }
  if( type>=RESERVED_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = RESERVED_BYTE;
    UnlockArea.lRange = 1L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "UNLOCK %d reserved res=%d\n", pFile->h, res ));
  }
  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
    res = unlockReadLock(pFile);
    OSTRACE(( "UNLOCK %d is %d want %d res=%d\n",
              pFile->h, type, locktype, res ));
  }
  if( type>=PENDING_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = PENDING_BYTE;
    UnlockArea.lRange = 1L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, LOCK_TIMEOUT, 0L );
    OSTRACE(( "UNLOCK %d pending res=%d\n", pFile->h, res ));
  }
  pFile->locktype = locktype;
  OSTRACE(( "UNLOCK %d now %d\n", pFile->h, pFile->locktype ));
  return rc;
}

/*
** Control and query of the open file handle.
*/
static int os2FileControl(sqlite3_file *id, int op, void *pArg){
  switch( op ){
    case SQLITE_FCNTL_LOCKSTATE: {
      *(int*)pArg = ((os2File*)id)->locktype;
      OSTRACE(( "FCNTL_LOCKSTATE %d lock=%d\n",
                ((os2File*)id)->h, ((os2File*)id)->locktype ));
      return SQLITE_OK;
    }
  }
  return SQLITE_ERROR;
}

/*
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  }
  j = sqlite3Strlen30( zBuf );
  sqlite3_randomness( 20, &zBuf[j] );
  for( i = 0; i < 20; i++, j++ ){
    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
  }
  zBuf[j] = 0;
  OSTRACE2( "TEMP FILENAME: %s\n", zBuf );
  return SQLITE_OK;
}


/*
** Turn a relative pathname into a full pathname.  Write the full
** pathname into zFull[].  zFull[] will be at least pVfs->mxPathname







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  }
  j = sqlite3Strlen30( zBuf );
  sqlite3_randomness( 20, &zBuf[j] );
  for( i = 0; i < 20; i++, j++ ){
    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
  }
  zBuf[j] = 0;
  OSTRACE(( "TEMP FILENAME: %s\n", zBuf ));
  return SQLITE_OK;
}


/*
** Turn a relative pathname into a full pathname.  Write the full
** pathname into zFull[].  zFull[] will be at least pVfs->mxPathname
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    }
    zName = zTmpname;
  }


  memset( pFile, 0, sizeof(*pFile) );

  OSTRACE2( "OPEN want %d\n", flags );

  if( flags & SQLITE_OPEN_READWRITE ){
    ulOpenMode |= OPEN_ACCESS_READWRITE;
    OSTRACE1( "OPEN read/write\n" );
  }else{
    ulOpenMode |= OPEN_ACCESS_READONLY;
    OSTRACE1( "OPEN read only\n" );
  }

  if( flags & SQLITE_OPEN_CREATE ){
    ulOpenFlags |= OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_CREATE_IF_NEW;
    OSTRACE1( "OPEN open new/create\n" );
  }else{
    ulOpenFlags |= OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_FAIL_IF_NEW;
    OSTRACE1( "OPEN open existing\n" );
  }

  if( flags & SQLITE_OPEN_MAIN_DB ){
    ulOpenMode |= OPEN_SHARE_DENYNONE;
    OSTRACE1( "OPEN share read/write\n" );
  }else{
    ulOpenMode |= OPEN_SHARE_DENYWRITE;
    OSTRACE1( "OPEN share read only\n" );
  }

  if( flags & SQLITE_OPEN_DELETEONCLOSE ){
    char pathUtf8[CCHMAXPATH];
#ifdef NDEBUG /* when debugging we want to make sure it is deleted */
    ulFileAttribute = FILE_HIDDEN;
#endif
    os2FullPathname( pVfs, zName, CCHMAXPATH, pathUtf8 );
    pFile->pathToDel = convertUtf8PathToCp( pathUtf8 );
    OSTRACE1( "OPEN hidden/delete on close file attributes\n" );
  }else{
    pFile->pathToDel = NULL;
    OSTRACE1( "OPEN normal file attribute\n" );
  }

  /* always open in random access mode for possibly better speed */
  ulOpenMode |= OPEN_FLAGS_RANDOM;
  ulOpenMode |= OPEN_FLAGS_FAIL_ON_ERROR;
  ulOpenMode |= OPEN_FLAGS_NOINHERIT;

  zNameCp = convertUtf8PathToCp( zName );
  rc = DosOpen( (PSZ)zNameCp,
                &h,
                &ulAction,
                0L,
                ulFileAttribute,
                ulOpenFlags,
                ulOpenMode,
                (PEAOP2)NULL );
  free( zNameCp );
  if( rc != NO_ERROR ){
    OSTRACE7( "OPEN Invalid handle rc=%d: zName=%s, ulAction=%#lx, ulAttr=%#lx, ulFlags=%#lx, ulMode=%#lx\n",
              rc, zName, ulAction, ulFileAttribute, ulOpenFlags, ulOpenMode );
    if( pFile->pathToDel )
      free( pFile->pathToDel );
    pFile->pathToDel = NULL;
    if( flags & SQLITE_OPEN_READWRITE ){

      OSTRACE2( "OPEN %d Invalid handle\n", ((flags | SQLITE_OPEN_READONLY) & ~SQLITE_OPEN_READWRITE) );
      return os2Open( pVfs, zName, id,
                      ((flags | SQLITE_OPEN_READONLY) & ~SQLITE_OPEN_READWRITE),
                      pOutFlags );
    }else{
      return SQLITE_CANTOPEN;
    }
  }

  if( pOutFlags ){
    *pOutFlags = flags & SQLITE_OPEN_READWRITE ? SQLITE_OPEN_READWRITE : SQLITE_OPEN_READONLY;
  }

  pFile->pMethod = &os2IoMethod;
  pFile->h = h;
  OpenCounter(+1);
  OSTRACE3( "OPEN %d pOutFlags=%d\n", pFile->h, pOutFlags );
  return SQLITE_OK;
}

/*
** Delete the named file.
*/
static int os2Delete(
  sqlite3_vfs *pVfs,                     /* Not used on os2 */
  const char *zFilename,                 /* Name of file to delete */
  int syncDir                            /* Not used on os2 */
){
  APIRET rc = NO_ERROR;
  char *zFilenameCp = convertUtf8PathToCp( zFilename );
  SimulateIOError( return SQLITE_IOERR_DELETE );
  rc = DosDelete( (PSZ)zFilenameCp );
  free( zFilenameCp );
  OSTRACE2( "DELETE \"%s\"\n", zFilename );
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR_DELETE;
}

/*
** Check the existance and status of a file.
*/
static int os2Access(
  sqlite3_vfs *pVfs,        /* Not used on os2 */
  const char *zFilename,    /* Name of file to check */
  int flags,                /* Type of test to make on this file */
  int *pOut                 /* Write results here */
){
  FILESTATUS3 fsts3ConfigInfo;
  APIRET rc = NO_ERROR;
  char *zFilenameCp = convertUtf8PathToCp( zFilename );

  memset( &fsts3ConfigInfo, 0, sizeof(fsts3ConfigInfo) );
  rc = DosQueryPathInfo( (PSZ)zFilenameCp, FIL_STANDARD,
                         &fsts3ConfigInfo, sizeof(FILESTATUS3) );
  free( zFilenameCp );
  OSTRACE4( "ACCESS fsts3ConfigInfo.attrFile=%d flags=%d rc=%d\n",
            fsts3ConfigInfo.attrFile, flags, rc );
  switch( flags ){
    case SQLITE_ACCESS_READ:
    case SQLITE_ACCESS_EXISTS:
      rc = (rc == NO_ERROR);
      OSTRACE3( "ACCESS %s access of read and exists  rc=%d\n", zFilename, rc );
      break;
    case SQLITE_ACCESS_READWRITE:
      rc = (rc == NO_ERROR) && ( (fsts3ConfigInfo.attrFile & FILE_READONLY) == 0 );
      OSTRACE3( "ACCESS %s access of read/write  rc=%d\n", zFilename, rc );
      break;
    default:
      assert( !"Invalid flags argument" );
  }
  *pOut = rc;
  return SQLITE_OK;
}







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    }
    zName = zTmpname;
  }


  memset( pFile, 0, sizeof(*pFile) );

  OSTRACE( "OPEN want %d\n", flags ));

  if( flags & SQLITE_OPEN_READWRITE ){
    ulOpenMode |= OPEN_ACCESS_READWRITE;
    OSTRACE(( "OPEN read/write\n" ));
  }else{
    ulOpenMode |= OPEN_ACCESS_READONLY;
    OSTRACE(( "OPEN read only\n" ));
  }

  if( flags & SQLITE_OPEN_CREATE ){
    ulOpenFlags |= OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_CREATE_IF_NEW;
    OSTRACE(( "OPEN open new/create\n" ));
  }else{
    ulOpenFlags |= OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_FAIL_IF_NEW;
    OSTRACE(( "OPEN open existing\n" ));
  }

  if( flags & SQLITE_OPEN_MAIN_DB ){
    ulOpenMode |= OPEN_SHARE_DENYNONE;
    OSTRACE(( "OPEN share read/write\n" ));
  }else{
    ulOpenMode |= OPEN_SHARE_DENYWRITE;
    OSTRACE(( "OPEN share read only\n" ));
  }

  if( flags & SQLITE_OPEN_DELETEONCLOSE ){
    char pathUtf8[CCHMAXPATH];
#ifdef NDEBUG /* when debugging we want to make sure it is deleted */
    ulFileAttribute = FILE_HIDDEN;
#endif
    os2FullPathname( pVfs, zName, CCHMAXPATH, pathUtf8 );
    pFile->pathToDel = convertUtf8PathToCp( pathUtf8 );
    OSTRACE(( "OPEN hidden/delete on close file attributes\n" ));
  }else{
    pFile->pathToDel = NULL;
    OSTRACE(( "OPEN normal file attribute\n" ));
  }

  /* always open in random access mode for possibly better speed */
  ulOpenMode |= OPEN_FLAGS_RANDOM;
  ulOpenMode |= OPEN_FLAGS_FAIL_ON_ERROR;
  ulOpenMode |= OPEN_FLAGS_NOINHERIT;

  zNameCp = convertUtf8PathToCp( zName );
  rc = DosOpen( (PSZ)zNameCp,
                &h,
                &ulAction,
                0L,
                ulFileAttribute,
                ulOpenFlags,
                ulOpenMode,
                (PEAOP2)NULL );
  free( zNameCp );
  if( rc != NO_ERROR ){
    OSTRACE(( "OPEN Invalid handle rc=%d: zName=%s, ulAction=%#lx, ulAttr=%#lx, ulFlags=%#lx, ulMode=%#lx\n",
              rc, zName, ulAction, ulFileAttribute, ulOpenFlags, ulOpenMode ));
    if( pFile->pathToDel )
      free( pFile->pathToDel );
    pFile->pathToDel = NULL;
    if( flags & SQLITE_OPEN_READWRITE ){
      OSTRACE(( "OPEN %d Invalid handle\n",
                ((flags | SQLITE_OPEN_READONLY) & ~SQLITE_OPEN_READWRITE) ));
      return os2Open( pVfs, zName, id,
                      ((flags | SQLITE_OPEN_READONLY) & ~SQLITE_OPEN_READWRITE),
                      pOutFlags );
    }else{
      return SQLITE_CANTOPEN;
    }
  }

  if( pOutFlags ){
    *pOutFlags = flags & SQLITE_OPEN_READWRITE ? SQLITE_OPEN_READWRITE : SQLITE_OPEN_READONLY;
  }

  pFile->pMethod = &os2IoMethod;
  pFile->h = h;
  OpenCounter(+1);
  OSTRACE(( "OPEN %d pOutFlags=%d\n", pFile->h, pOutFlags ));
  return SQLITE_OK;
}

/*
** Delete the named file.
*/
static int os2Delete(
  sqlite3_vfs *pVfs,                     /* Not used on os2 */
  const char *zFilename,                 /* Name of file to delete */
  int syncDir                            /* Not used on os2 */
){
  APIRET rc = NO_ERROR;
  char *zFilenameCp = convertUtf8PathToCp( zFilename );
  SimulateIOError( return SQLITE_IOERR_DELETE );
  rc = DosDelete( (PSZ)zFilenameCp );
  free( zFilenameCp );
  OSTRACE(( "DELETE \"%s\"\n", zFilename ));
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR_DELETE;
}

/*
** Check the existance and status of a file.
*/
static int os2Access(
  sqlite3_vfs *pVfs,        /* Not used on os2 */
  const char *zFilename,    /* Name of file to check */
  int flags,                /* Type of test to make on this file */
  int *pOut                 /* Write results here */
){
  FILESTATUS3 fsts3ConfigInfo;
  APIRET rc = NO_ERROR;
  char *zFilenameCp = convertUtf8PathToCp( zFilename );

  memset( &fsts3ConfigInfo, 0, sizeof(fsts3ConfigInfo) );
  rc = DosQueryPathInfo( (PSZ)zFilenameCp, FIL_STANDARD,
                         &fsts3ConfigInfo, sizeof(FILESTATUS3) );
  free( zFilenameCp );
  OSTRACE(( "ACCESS fsts3ConfigInfo.attrFile=%d flags=%d rc=%d\n",
            fsts3ConfigInfo.attrFile, flags, rc ));
  switch( flags ){
    case SQLITE_ACCESS_READ:
    case SQLITE_ACCESS_EXISTS:
      rc = (rc == NO_ERROR);
      OSTRACE(( "ACCESS %s access of read and exists  rc=%d\n", zFilename, rc));
      break;
    case SQLITE_ACCESS_READWRITE:
      rc = (rc == NO_ERROR) && ( (fsts3ConfigInfo.attrFile & FILE_READONLY) == 0 );
      OSTRACE(( "ACCESS %s access of read/write  rc=%d\n", zFilename, rc ));
      break;
    default:
      assert( !"Invalid flags argument" );
  }
  *pOut = rc;
  return SQLITE_OK;
}
Changes to src/os_unix.c.
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/*
** Only set the lastErrno if the error code is a real error and not 
** a normal expected return code of SQLITE_BUSY or SQLITE_OK
*/
#define IS_LOCK_ERROR(x)  ((x != SQLITE_OK) && (x != SQLITE_BUSY))







/*
** Sometimes, after a file handle is closed by SQLite, the file descriptor
** cannot be closed immediately. In these cases, instances of the following
** structure are used to store the file descriptor while waiting for an
** opportunity to either close or reuse it.
*/
typedef struct UnixUnusedFd UnixUnusedFd;
struct UnixUnusedFd {
  int fd;                   /* File descriptor to close */
  int flags;                /* Flags this file descriptor was opened with */
  UnixUnusedFd *pNext;      /* Next unused file descriptor on same file */
};

/*
** The unixFile structure is subclass of sqlite3_file specific to the unix
** VFS implementations.
*/
typedef struct unixFile unixFile;
struct unixFile {
  sqlite3_io_methods const *pMethod;  /* Always the first entry */
  struct unixOpenCnt *pOpen;       /* Info about all open fd's on this inode */
  struct unixLockInfo *pLock;      /* Info about locks on this inode */
  int h;                           /* The file descriptor */
  int dirfd;                       /* File descriptor for the directory */
  unsigned char locktype;          /* The type of lock held on this fd */
  int lastErrno;                   /* The unix errno from the last I/O error */
  void *lockingContext;            /* Locking style specific state */
  UnixUnusedFd *pUnused;           /* Pre-allocated UnixUnusedFd */
  int fileFlags;                   /* Miscellanous flags */


#if SQLITE_ENABLE_LOCKING_STYLE
  int openFlags;                   /* The flags specified at open() */
#endif
#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
  unsigned fsFlags;                 /* cached details from statfs() */
#endif
#if SQLITE_THREADSAFE && defined(__linux__)
  pthread_t tid;                   /* The thread that "owns" this unixFile */
#endif
#if OS_VXWORKS
  int isDelete;                    /* Delete on close if true */
  struct vxworksFileId *pId;       /* Unique file ID */
#endif
#ifndef NDEBUG
  /* The next group of variables are used to track whether or not the
  ** transaction counter in bytes 24-27 of database files are updated
  ** whenever any part of the database changes.  An assertion fault will
  ** occur if a file is updated without also updating the transaction
  ** counter.  This test is made to avoid new problems similar to the







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/*
** Only set the lastErrno if the error code is a real error and not 
** a normal expected return code of SQLITE_BUSY or SQLITE_OK
*/
#define IS_LOCK_ERROR(x)  ((x != SQLITE_OK) && (x != SQLITE_BUSY))

/* Forward references */
typedef struct unixShm unixShm;               /* Connection shared memory */
typedef struct unixShmNode unixShmNode;       /* Shared memory instance */
typedef struct unixInodeInfo unixInodeInfo;   /* An i-node */
typedef struct UnixUnusedFd UnixUnusedFd;     /* An unused file descriptor */

/*
** Sometimes, after a file handle is closed by SQLite, the file descriptor
** cannot be closed immediately. In these cases, instances of the following
** structure are used to store the file descriptor while waiting for an
** opportunity to either close or reuse it.
*/

struct UnixUnusedFd {
  int fd;                   /* File descriptor to close */
  int flags;                /* Flags this file descriptor was opened with */
  UnixUnusedFd *pNext;      /* Next unused file descriptor on same file */
};

/*
** The unixFile structure is subclass of sqlite3_file specific to the unix
** VFS implementations.
*/
typedef struct unixFile unixFile;
struct unixFile {
  sqlite3_io_methods const *pMethod;  /* Always the first entry */

  unixInodeInfo *pInode;              /* Info about locks on this inode */
  int h;                              /* The file descriptor */
  int dirfd;                          /* File descriptor for the directory */
  unsigned char eFileLock;            /* The type of lock held on this fd */
  int lastErrno;                      /* The unix errno from last I/O error */
  void *lockingContext;               /* Locking style specific state */
  UnixUnusedFd *pUnused;              /* Pre-allocated UnixUnusedFd */
  int fileFlags;                      /* Miscellanous flags */
  const char *zPath;                  /* Name of the file */
  unixShm *pShm;                      /* Shared memory segment information */
#if SQLITE_ENABLE_LOCKING_STYLE
  int openFlags;                      /* The flags specified at open() */
#endif
#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
  unsigned fsFlags;                   /* cached details from statfs() */
#endif



#if OS_VXWORKS
  int isDelete;                       /* Delete on close if true */
  struct vxworksFileId *pId;          /* Unique file ID */
#endif
#ifndef NDEBUG
  /* The next group of variables are used to track whether or not the
  ** transaction counter in bytes 24-27 of database files are updated
  ** whenever any part of the database changes.  An assertion fault will
  ** occur if a file is updated without also updating the transaction
  ** counter.  This test is made to avoid new problems similar to the
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#else
#define threadid 0
#endif


/*
** Helper functions to obtain and relinquish the global mutex. The
** global mutex is used to protect the unixOpenCnt, unixLockInfo and
** vxworksFileId objects used by this file, all of which may be 
** shared by multiple threads.
**
** Function unixMutexHeld() is used to assert() that the global mutex 
** is held when required. This function is only used as part of assert() 
** statements. e.g.
**







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#else
#define threadid 0
#endif


/*
** Helper functions to obtain and relinquish the global mutex. The
** global mutex is used to protect the unixInodeInfo and
** vxworksFileId objects used by this file, all of which may be 
** shared by multiple threads.
**
** Function unixMutexHeld() is used to assert() that the global mutex 
** is held when required. This function is only used as part of assert() 
** statements. e.g.
**
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#ifdef SQLITE_DEBUG
/*
** Helper function for printing out trace information from debugging
** binaries. This returns the string represetation of the supplied
** integer lock-type.
*/
static const char *locktypeName(int locktype){
  switch( locktype ){
    case NO_LOCK: return "NONE";
    case SHARED_LOCK: return "SHARED";
    case RESERVED_LOCK: return "RESERVED";
    case PENDING_LOCK: return "PENDING";
    case EXCLUSIVE_LOCK: return "EXCLUSIVE";
  }
  return "ERROR";







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|







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#ifdef SQLITE_DEBUG
/*
** Helper function for printing out trace information from debugging
** binaries. This returns the string represetation of the supplied
** integer lock-type.
*/
static const char *azFileLock(int eFileLock){
  switch( eFileLock ){
    case NO_LOCK: return "NONE";
    case SHARED_LOCK: return "SHARED";
    case RESERVED_LOCK: return "RESERVED";
    case PENDING_LOCK: return "PENDING";
    case EXCLUSIVE_LOCK: return "EXCLUSIVE";
  }
  return "ERROR";
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** POSIX lock if the internal lock structure transitions between
** a locked and an unlocked state.
**
** But wait:  there are yet more problems with POSIX advisory locks.
**
** If you close a file descriptor that points to a file that has locks,
** all locks on that file that are owned by the current process are
** released.  To work around this problem, each unixFile structure contains
** a pointer to an unixOpenCnt structure.  There is one unixOpenCnt structure
** per open inode, which means that multiple unixFile can point to a single
** unixOpenCnt.  When an attempt is made to close an unixFile, if there are
** other unixFile open on the same inode that are holding locks, the call
** to close() the file descriptor is deferred until all of the locks clear.
** The unixOpenCnt structure keeps a list of file descriptors that need to
** be closed and that list is walked (and cleared) when the last lock
** clears.
**
** Yet another problem:  LinuxThreads do not play well with posix locks.
**
** Many older versions of linux use the LinuxThreads library which is
** not posix compliant.  Under LinuxThreads, a lock created by thread
** A cannot be modified or overridden by a different thread B.
** Only thread A can modify the lock.  Locking behavior is correct
** if the appliation uses the newer Native Posix Thread Library (NPTL)
** on linux - with NPTL a lock created by thread A can override locks
** in thread B.  But there is no way to know at compile-time which
** threading library is being used.  So there is no way to know at
** compile-time whether or not thread A can override locks on thread B.
** We have to do a run-time check to discover the behavior of the
** current process.
**
** On systems where thread A is unable to modify locks created by
** thread B, we have to keep track of which thread created each
** lock.  Hence there is an extra field in the key to the unixLockInfo
** structure to record this information.  And on those systems it
** is illegal to begin a transaction in one thread and finish it
** in another.  For this latter restriction, there is no work-around.
** It is a limitation of LinuxThreads.
*/

/*
** Set or check the unixFile.tid field.  This field is set when an unixFile
** is first opened.  All subsequent uses of the unixFile verify that the
** same thread is operating on the unixFile.  Some operating systems do
** not allow locks to be overridden by other threads and that restriction
** means that sqlite3* database handles cannot be moved from one thread
** to another while locks are held.
**
** Version 3.3.1 (2006-01-15):  unixFile can be moved from one thread to
** another as long as we are running on a system that supports threads
** overriding each others locks (which is now the most common behavior)
** or if no locks are held.  But the unixFile.pLock field needs to be
** recomputed because its key includes the thread-id.  See the 
** transferOwnership() function below for additional information
*/
#if SQLITE_THREADSAFE && defined(__linux__)
# define SET_THREADID(X)   (X)->tid = pthread_self()
# define CHECK_THREADID(X) (threadsOverrideEachOthersLocks==0 && \
                            !pthread_equal((X)->tid, pthread_self()))
#else
# define SET_THREADID(X)
# define CHECK_THREADID(X) 0
#endif

/*
** An instance of the following structure serves as the key used
** to locate a particular unixOpenCnt structure given its inode.  This
** is the same as the unixLockKey except that the thread ID is omitted.
*/
struct unixFileId {
  dev_t dev;                  /* Device number */
#if OS_VXWORKS
  struct vxworksFileId *pId;  /* Unique file ID for vxworks. */
#else
  ino_t ino;                  /* Inode number */
#endif
};

/*
** An instance of the following structure serves as the key used
** to locate a particular unixLockInfo structure given its inode.
**
** If threads cannot override each others locks (LinuxThreads), then we
** set the unixLockKey.tid field to the thread ID.  If threads can override
** each others locks (Posix and NPTL) then tid is always set to zero.
** tid is omitted if we compile without threading support or on an OS
** other than linux.
*/
struct unixLockKey {
  struct unixFileId fid;  /* Unique identifier for the file */
#if SQLITE_THREADSAFE && defined(__linux__)
  pthread_t tid;  /* Thread ID of lock owner. Zero if not using LinuxThreads */
#endif
};

/*
** An instance of the following structure is allocated for each open
** inode.  Or, on LinuxThreads, there is one of these structures for
** each inode opened by each thread.
**
** A single inode can have multiple file descriptors, so each unixFile
** structure contains a pointer to an instance of this object and this
** object keeps a count of the number of unixFile pointing to it.
*/
struct unixLockInfo {
  struct unixLockKey lockKey;     /* The lookup key */
  int cnt;                        /* Number of SHARED locks held */
  int locktype;                   /* One of SHARED_LOCK, RESERVED_LOCK etc. */
  int nRef;                       /* Number of pointers to this structure */





#if defined(SQLITE_ENABLE_LOCKING_STYLE)
  unsigned long long sharedByte;  /* for AFP simulated shared lock */
#endif
  struct unixLockInfo *pNext;     /* List of all unixLockInfo objects */
  struct unixLockInfo *pPrev;     /*    .... doubly linked */
};

/*
** An instance of the following structure is allocated for each open
** inode.  This structure keeps track of the number of locks on that
** inode.  If a close is attempted against an inode that is holding
** locks, the close is deferred until all locks clear by adding the
** file descriptor to be closed to the pending list.
**
** TODO:  Consider changing this so that there is only a single file
** descriptor for each open file, even when it is opened multiple times.
** The close() system call would only occur when the last database
** using the file closes.
*/
struct unixOpenCnt {
  struct unixFileId fileId;   /* The lookup key */
  int nRef;                   /* Number of pointers to this structure */
  int nLock;                  /* Number of outstanding locks */
  UnixUnusedFd *pUnused;      /* Unused file descriptors to close */
#if OS_VXWORKS
  sem_t *pSem;                     /* Named POSIX semaphore */
  char aSemName[MAX_PATHNAME+2];   /* Name of that semaphore */
#endif
  struct unixOpenCnt *pNext, *pPrev;   /* List of all unixOpenCnt objects */
};

/*
** Lists of all unixLockInfo and unixOpenCnt objects.  These used to be hash
** tables.  But the number of objects is rarely more than a dozen and
** never exceeds a few thousand.  And lookup is not on a critical
** path so a simple linked list will suffice.
*/
static struct unixLockInfo *lockList = 0;
static struct unixOpenCnt *openList = 0;

/*
** This variable remembers whether or not threads can override each others
** locks.
**
**    0:  No.  Threads cannot override each others locks.  (LinuxThreads)
**    1:  Yes.  Threads can override each others locks.  (Posix & NLPT)
**   -1:  We don't know yet.
**
** On some systems, we know at compile-time if threads can override each
** others locks.  On those systems, the SQLITE_THREAD_OVERRIDE_LOCK macro
** will be set appropriately.  On other systems, we have to check at
** runtime.  On these latter systems, SQLTIE_THREAD_OVERRIDE_LOCK is
** undefined.
**
** This variable normally has file scope only.  But during testing, we make
** it a global so that the test code can change its value in order to verify
** that the right stuff happens in either case.
*/
#if SQLITE_THREADSAFE && defined(__linux__)
#  ifndef SQLITE_THREAD_OVERRIDE_LOCK
#    define SQLITE_THREAD_OVERRIDE_LOCK -1
#  endif
#  ifdef SQLITE_TEST
int threadsOverrideEachOthersLocks = SQLITE_THREAD_OVERRIDE_LOCK;
#  else
static int threadsOverrideEachOthersLocks = SQLITE_THREAD_OVERRIDE_LOCK;
#  endif
#endif

/*
** This structure holds information passed into individual test
** threads by the testThreadLockingBehavior() routine.
*/
struct threadTestData {
  int fd;                /* File to be locked */
  struct flock lock;     /* The locking operation */
  int result;            /* Result of the locking operation */
};

#if SQLITE_THREADSAFE && defined(__linux__)
/*
** This function is used as the main routine for a thread launched by
** testThreadLockingBehavior(). It tests whether the shared-lock obtained
** by the main thread in testThreadLockingBehavior() conflicts with a
** hypothetical write-lock obtained by this thread on the same file.

**
** The write-lock is not actually acquired, as this is not possible if 
** the file is open in read-only mode (see ticket #3472).

*/ 
static void *threadLockingTest(void *pArg){
  struct threadTestData *pData = (struct threadTestData*)pArg;
  pData->result = fcntl(pData->fd, F_GETLK, &pData->lock);

  return pArg;
}
#endif /* SQLITE_THREADSAFE && defined(__linux__) */


#if SQLITE_THREADSAFE && defined(__linux__)
/*
** This procedure attempts to determine whether or not threads
** can override each others locks then sets the 
** threadsOverrideEachOthersLocks variable appropriately.
*/
static void testThreadLockingBehavior(int fd_orig){
  int fd;
  int rc;
  struct threadTestData d;
  struct flock l;
  pthread_t t;

  fd = dup(fd_orig);
  if( fd<0 ) return;
  memset(&l, 0, sizeof(l));
  l.l_type = F_RDLCK;
  l.l_len = 1;

  l.l_start = 0;
  l.l_whence = SEEK_SET;
  rc = fcntl(fd_orig, F_SETLK, &l);
  if( rc!=0 ) return;
  memset(&d, 0, sizeof(d));
  d.fd = fd;
  d.lock = l;
  d.lock.l_type = F_WRLCK;
  if( pthread_create(&t, 0, threadLockingTest, &d)==0 ){
    pthread_join(t, 0);
  }
  close(fd);
  if( d.result!=0 ) return;
  threadsOverrideEachOthersLocks = (d.lock.l_type==F_UNLCK);
}
#endif /* SQLITE_THREADSAFE && defined(__linux__) */

/*
** Release a unixLockInfo structure previously allocated by findLockInfo().
**
** The mutex entered using the unixEnterMutex() function must be held
** when this function is called.
*/
static void releaseLockInfo(struct unixLockInfo *pLock){
  assert( unixMutexHeld() );
  if( pLock ){
    pLock->nRef--;
    if( pLock->nRef==0 ){
      if( pLock->pPrev ){
        assert( pLock->pPrev->pNext==pLock );
        pLock->pPrev->pNext = pLock->pNext;
      }else{
        assert( lockList==pLock );
        lockList = pLock->pNext;
      }
      if( pLock->pNext ){
        assert( pLock->pNext->pPrev==pLock );
        pLock->pNext->pPrev = pLock->pPrev;
      }
      sqlite3_free(pLock);
    }
  }
}

/*
** Release a unixOpenCnt structure previously allocated by findLockInfo().
**
** The mutex entered using the unixEnterMutex() function must be held
** when this function is called.
*/
static void releaseOpenCnt(struct unixOpenCnt *pOpen){
  assert( unixMutexHeld() );
  if( pOpen ){
    pOpen->nRef--;
    if( pOpen->nRef==0 ){
      if( pOpen->pPrev ){
        assert( pOpen->pPrev->pNext==pOpen );
        pOpen->pPrev->pNext = pOpen->pNext;
      }else{
        assert( openList==pOpen );
        openList = pOpen->pNext;
      }
      if( pOpen->pNext ){
        assert( pOpen->pNext->pPrev==pOpen );
        pOpen->pNext->pPrev = pOpen->pPrev;
      }
#if SQLITE_THREADSAFE && defined(__linux__)
      assert( !pOpen->pUnused || threadsOverrideEachOthersLocks==0 );
#endif

      /* If pOpen->pUnused is not null, then memory and file-descriptors
      ** are leaked.
      **
      ** This will only happen if, under Linuxthreads, the user has opened
      ** a transaction in one thread, then attempts to close the database
      ** handle from another thread (without first unlocking the db file).
      ** This is a misuse.  */
      sqlite3_free(pOpen);
    }
  }
}

/*
** Given a file descriptor, locate unixLockInfo and unixOpenCnt structures that
** describes that file descriptor.  Create new ones if necessary.  The
** return values might be uninitialized if an error occurs.
**
** The mutex entered using the unixEnterMutex() function must be held
** when this function is called.
**
** Return an appropriate error code.
*/
static int findLockInfo(
  unixFile *pFile,               /* Unix file with file desc used in the key */
  struct unixLockInfo **ppLock,  /* Return the unixLockInfo structure here */
  struct unixOpenCnt **ppOpen    /* Return the unixOpenCnt structure here */
){
  int rc;                        /* System call return code */
  int fd;                        /* The file descriptor for pFile */
  struct unixLockKey lockKey;    /* Lookup key for the unixLockInfo structure */
  struct unixFileId fileId;      /* Lookup key for the unixOpenCnt struct */
  struct stat statbuf;           /* Low-level file information */
  struct unixLockInfo *pLock = 0;/* Candidate unixLockInfo object */
  struct unixOpenCnt *pOpen;     /* Candidate unixOpenCnt object */

  assert( unixMutexHeld() );

  /* Get low-level information about the file that we can used to
  ** create a unique name for the file.
  */
  fd = pFile->h;







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** POSIX lock if the internal lock structure transitions between
** a locked and an unlocked state.
**
** But wait:  there are yet more problems with POSIX advisory locks.
**
** If you close a file descriptor that points to a file that has locks,
** all locks on that file that are owned by the current process are
** released.  To work around this problem, each unixInodeInfo object
** maintains a count of the number of pending locks on tha inode.

** When an attempt is made to close an unixFile, if there are
** other unixFile open on the same inode that are holding locks, the call
** to close() the file descriptor is deferred until all of the locks clear.
** The unixInodeInfo structure keeps a list of file descriptors that need to
** be closed and that list is walked (and cleared) when the last lock
** clears.
**
** Yet another problem:  LinuxThreads do not play well with posix locks.
**
** Many older versions of linux use the LinuxThreads library which is
** not posix compliant.  Under LinuxThreads, a lock created by thread
** A cannot be modified or overridden by a different thread B.
** Only thread A can modify the lock.  Locking behavior is correct
** if the appliation uses the newer Native Posix Thread Library (NPTL)
** on linux - with NPTL a lock created by thread A can override locks
** in thread B.  But there is no way to know at compile-time which
** threading library is being used.  So there is no way to know at
** compile-time whether or not thread A can override locks on thread B.
** One has to do a run-time check to discover the behavior of the
** current process.
**






** SQLite used to support LinuxThreads.  But support for LinuxThreads

** was dropped beginning with version 3.7.0.  SQLite will still work with




** LinuxThreads provided that (1) there is no more than one connection 
** per database file in the same process and (2) database connections

** do not move across threads.






*/









/*
** An instance of the following structure serves as the key used
** to locate a particular unixInodeInfo object.

*/
struct unixFileId {
  dev_t dev;                  /* Device number */
#if OS_VXWORKS
  struct vxworksFileId *pId;  /* Unique file ID for vxworks. */
#else
  ino_t ino;                  /* Inode number */
#endif
};


















/*
** An instance of the following structure is allocated for each open
** inode.  Or, on LinuxThreads, there is one of these structures for
** each inode opened by each thread.
**
** A single inode can have multiple file descriptors, so each unixFile
** structure contains a pointer to an instance of this object and this
** object keeps a count of the number of unixFile pointing to it.
*/
struct unixInodeInfo {
  struct unixFileId fileId;       /* The lookup key */
  int nShared;                    /* Number of SHARED locks held */
  int eFileLock;                  /* One of SHARED_LOCK, RESERVED_LOCK etc. */
  int nRef;                       /* Number of pointers to this structure */
  unixShmNode *pShmNode;          /* Shared memory associated with this inode */
  int nLock;                      /* Number of outstanding file locks */
  UnixUnusedFd *pUnused;          /* Unused file descriptors to close */
  unixInodeInfo *pNext;           /* List of all unixInodeInfo objects */
  unixInodeInfo *pPrev;           /*    .... doubly linked */
#if defined(SQLITE_ENABLE_LOCKING_STYLE)
  unsigned long long sharedByte;  /* for AFP simulated shared lock */
#endif





















#if OS_VXWORKS
  sem_t *pSem;                    /* Named POSIX semaphore */
  char aSemName[MAX_PATHNAME+2];  /* Name of that semaphore */
#endif

};










/*

** A lists of all unixInodeInfo objects.














*/










static unixInodeInfo *inodeList = 0;











/*




** Release a unixInodeInfo structure previously allocated by findInodeInfo().
**
** The mutex entered using the unixEnterMutex() function must be held

** when this function is called.
*/
static void releaseInodeInfo(unixInodeInfo *pInode){


  assert( unixMutexHeld() );
  if( pInode ){


    pInode->nRef--;
    if( pInode->nRef==0 ){












      assert( pInode->pShmNode==0 );

      if( pInode->pPrev ){



        assert( pInode->pPrev->pNext==pInode );






























        pInode->pPrev->pNext = pInode->pNext;
      }else{
        assert( inodeList==pInode );
        inodeList = pInode->pNext;
      }
      if( pInode->pNext ){
        assert( pInode->pNext->pPrev==pInode );
        pInode->pNext->pPrev = pInode->pPrev;
      }
      sqlite3_free(pInode);
    }
  }
}

/*






































** Given a file descriptor, locate the unixInodeInfo object that
** describes that file descriptor.  Create a new one if necessary.  The
** return value might be uninitialized if an error occurs.
**
** The mutex entered using the unixEnterMutex() function must be held
** when this function is called.
**
** Return an appropriate error code.
*/
static int findInodeInfo(
  unixFile *pFile,               /* Unix file with file desc used in the key */
  unixInodeInfo **ppInode        /* Return the unixInodeInfo object here */

){
  int rc;                        /* System call return code */
  int fd;                        /* The file descriptor for pFile */

  struct unixFileId fileId;      /* Lookup key for the unixInodeInfo */
  struct stat statbuf;           /* Low-level file information */

  unixInodeInfo *pInode = 0;     /* Candidate unixInodeInfo object */

  assert( unixMutexHeld() );

  /* Get low-level information about the file that we can used to
  ** create a unique name for the file.
  */
  fd = pFile->h;
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    if( rc!=0 ){
      pFile->lastErrno = errno;
      return SQLITE_IOERR;
    }
  }
#endif

  memset(&lockKey, 0, sizeof(lockKey));
  lockKey.fid.dev = statbuf.st_dev;
#if OS_VXWORKS
  lockKey.fid.pId = pFile->pId;
#else
  lockKey.fid.ino = statbuf.st_ino;
#endif
#if SQLITE_THREADSAFE && defined(__linux__)
  if( threadsOverrideEachOthersLocks<0 ){
    testThreadLockingBehavior(fd);
  }
  lockKey.tid = threadsOverrideEachOthersLocks ? 0 : pthread_self();
#endif
  fileId = lockKey.fid;
  if( ppLock!=0 ){
    pLock = lockList;
    while( pLock && memcmp(&lockKey, &pLock->lockKey, sizeof(lockKey)) ){
      pLock = pLock->pNext;
    }
    if( pLock==0 ){
      pLock = sqlite3_malloc( sizeof(*pLock) );
      if( pLock==0 ){
        rc = SQLITE_NOMEM;
        goto exit_findlockinfo;
      }
      memcpy(&pLock->lockKey,&lockKey,sizeof(lockKey));
      pLock->nRef = 1;
      pLock->cnt = 0;
      pLock->locktype = 0;
#if defined(SQLITE_ENABLE_LOCKING_STYLE)
      pLock->sharedByte = 0;
#endif
      pLock->pNext = lockList;
      pLock->pPrev = 0;
      if( lockList ) lockList->pPrev = pLock;
      lockList = pLock;
    }else{
      pLock->nRef++;
    }
    *ppLock = pLock;
  }
  if( ppOpen!=0 ){
    pOpen = openList;
    while( pOpen && memcmp(&fileId, &pOpen->fileId, sizeof(fileId)) ){
      pOpen = pOpen->pNext;
    }
    if( pOpen==0 ){
      pOpen = sqlite3_malloc( sizeof(*pOpen) );
      if( pOpen==0 ){
        releaseLockInfo(pLock);
        rc = SQLITE_NOMEM;
        goto exit_findlockinfo;
      }
      memset(pOpen, 0, sizeof(*pOpen));
      pOpen->fileId = fileId;
      pOpen->nRef = 1;
      pOpen->pNext = openList;
      if( openList ) openList->pPrev = pOpen;

      openList = pOpen;
    }else{
      pOpen->nRef++;
    }
    *ppOpen = pOpen;
  }

exit_findlockinfo:
  return rc;
}

/*
** If we are currently in a different thread than the thread that the
** unixFile argument belongs to, then transfer ownership of the unixFile
** over to the current thread.
**
** A unixFile is only owned by a thread on systems that use LinuxThreads.
**
** Ownership transfer is only allowed if the unixFile is currently unlocked.
** If the unixFile is locked and an ownership is wrong, then return
** SQLITE_MISUSE.  SQLITE_OK is returned if everything works.
*/
#if SQLITE_THREADSAFE && defined(__linux__)
static int transferOwnership(unixFile *pFile){
  int rc;
  pthread_t hSelf;
  if( threadsOverrideEachOthersLocks ){
    /* Ownership transfers not needed on this system */
    return SQLITE_OK;
  }
  hSelf = pthread_self();
  if( pthread_equal(pFile->tid, hSelf) ){
    /* We are still in the same thread */
    OSTRACE1("No-transfer, same thread\n");
    return SQLITE_OK;
  }
  if( pFile->locktype!=NO_LOCK ){
    /* We cannot change ownership while we are holding a lock! */
    return SQLITE_MISUSE_BKPT;
  }
  OSTRACE4("Transfer ownership of %d from %d to %d\n",
            pFile->h, pFile->tid, hSelf);
  pFile->tid = hSelf;
  if (pFile->pLock != NULL) {
    releaseLockInfo(pFile->pLock);
    rc = findLockInfo(pFile, &pFile->pLock, 0);
    OSTRACE5("LOCK    %d is now %s(%s,%d)\n", pFile->h,
           locktypeName(pFile->locktype),
           locktypeName(pFile->pLock->locktype), pFile->pLock->cnt);
    return rc;
  } else {
    return SQLITE_OK;
  }
}
#else  /* if not SQLITE_THREADSAFE */
  /* On single-threaded builds, ownership transfer is a no-op */
# define transferOwnership(X) SQLITE_OK
#endif /* SQLITE_THREADSAFE */


/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, set *pResOut
** to a non-zero value otherwise *pResOut is set to zero.  The return value
** is set to SQLITE_OK unless an I/O error occurs during lock checking.
*/
static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
  int rc = SQLITE_OK;
  int reserved = 0;
  unixFile *pFile = (unixFile*)id;

  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );

  assert( pFile );
  unixEnterMutex(); /* Because pFile->pLock is shared across threads */

  /* Check if a thread in this process holds such a lock */
  if( pFile->pLock->locktype>SHARED_LOCK ){
    reserved = 1;
  }

  /* Otherwise see if some other process holds it.
  */
#ifndef __DJGPP__
  if( !reserved ){







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833



























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    if( rc!=0 ){
      pFile->lastErrno = errno;
      return SQLITE_IOERR;
    }
  }
#endif

  memset(&fileId, 0, sizeof(fileId));
  fileId.dev = statbuf.st_dev;
#if OS_VXWORKS
  fileId.pId = pFile->pId;
#else
  fileId.ino = statbuf.st_ino;
#endif








  pInode = inodeList;



























  while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){
    pInode = pInode->pNext;
  }
  if( pInode==0 ){
    pInode = sqlite3_malloc( sizeof(*pInode) );
    if( pInode==0 ){

      return SQLITE_NOMEM;

    }
    memset(pInode, 0, sizeof(*pInode));
    memcpy(&pInode->fileId, &fileId, sizeof(fileId));
    pInode->nRef = 1;
    pInode->pNext = inodeList;
    pInode->pPrev = 0;
    if( inodeList ) inodeList->pPrev = pInode;
    inodeList = pInode;
  }else{
    pInode->nRef++;
  }


  *ppInode = pInode;





















  return SQLITE_OK;
}






























/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, set *pResOut
** to a non-zero value otherwise *pResOut is set to zero.  The return value
** is set to SQLITE_OK unless an I/O error occurs during lock checking.
*/
static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
  int rc = SQLITE_OK;
  int reserved = 0;
  unixFile *pFile = (unixFile*)id;

  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );

  assert( pFile );
  unixEnterMutex(); /* Because pFile->pInode is shared across threads */

  /* Check if a thread in this process holds such a lock */
  if( pFile->pInode->eFileLock>SHARED_LOCK ){
    reserved = 1;
  }

  /* Otherwise see if some other process holds it.
  */
#ifndef __DJGPP__
  if( !reserved ){
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1195
    } else if( lock.l_type!=F_UNLCK ){
      reserved = 1;
    }
  }
#endif
  
  unixLeaveMutex();
  OSTRACE4("TEST WR-LOCK %d %d %d (unix)\n", pFile->h, rc, reserved);

  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**







|






|







891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
    } else if( lock.l_type!=F_UNLCK ){
      reserved = 1;
    }
  }
#endif
  
  unixLeaveMutex();
  OSTRACE(("TEST WR-LOCK %d %d %d (unix)\n", pFile->h, rc, reserved));

  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter eFileLock - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
**    SHARED -> (PENDING) -> EXCLUSIVE
**    RESERVED -> (PENDING) -> EXCLUSIVE
**    PENDING -> EXCLUSIVE
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int unixLock(sqlite3_file *id, int locktype){
  /* The following describes the implementation of the various locks and
  ** lock transitions in terms of the POSIX advisory shared and exclusive
  ** lock primitives (called read-locks and write-locks below, to avoid
  ** confusion with SQLite lock names). The algorithms are complicated
  ** slightly in order to be compatible with windows systems simultaneously
  ** accessing the same database file, in case that is ever required.
  **







|







921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
**    SHARED -> (PENDING) -> EXCLUSIVE
**    RESERVED -> (PENDING) -> EXCLUSIVE
**    PENDING -> EXCLUSIVE
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int unixLock(sqlite3_file *id, int eFileLock){
  /* The following describes the implementation of the various locks and
  ** lock transitions in terms of the POSIX advisory shared and exclusive
  ** lock primitives (called read-locks and write-locks below, to avoid
  ** confusion with SQLite lock names). The algorithms are complicated
  ** slightly in order to be compatible with windows systems simultaneously
  ** accessing the same database file, in case that is ever required.
  **
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
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1258
1259
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1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
  ** The reason a single byte cannot be used instead of the 'shared byte
  ** range' is that some versions of windows do not support read-locks. By
  ** locking a random byte from a range, concurrent SHARED locks may exist
  ** even if the locking primitive used is always a write-lock.
  */
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  struct unixLockInfo *pLock = pFile->pLock;
  struct flock lock;
  int s = 0;
  int tErrno = 0;

  assert( pFile );
  OSTRACE7("LOCK    %d %s was %s(%s,%d) pid=%d (unix)\n", pFile->h,
      locktypeName(locktype), locktypeName(pFile->locktype),
      locktypeName(pLock->locktype), pLock->cnt , getpid());

  /* If there is already a lock of this type or more restrictive on the
  ** unixFile, do nothing. Don't use the end_lock: exit path, as
  ** unixEnterMutex() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){
    OSTRACE3("LOCK    %d %s ok (already held) (unix)\n", pFile->h,
            locktypeName(locktype));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct.
  **  (1) We never move from unlocked to anything higher than shared lock.
  **  (2) SQLite never explicitly requests a pendig lock.
  **  (3) A shared lock is always held when a reserve lock is requested.
  */
  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
  assert( locktype!=PENDING_LOCK );
  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );

  /* This mutex is needed because pFile->pLock is shared across threads
  */
  unixEnterMutex();

  /* Make sure the current thread owns the pFile.
  */
  rc = transferOwnership(pFile);
  if( rc!=SQLITE_OK ){
    unixLeaveMutex();
    return rc;
  }
  pLock = pFile->pLock;

  /* If some thread using this PID has a lock via a different unixFile*
  ** handle that precludes the requested lock, return BUSY.
  */
  if( (pFile->locktype!=pLock->locktype && 
          (pLock->locktype>=PENDING_LOCK || locktype>SHARED_LOCK))
  ){
    rc = SQLITE_BUSY;
    goto end_lock;
  }

  /* If a SHARED lock is requested, and some thread using this PID already
  ** has a SHARED or RESERVED lock, then increment reference counts and
  ** return SQLITE_OK.
  */
  if( locktype==SHARED_LOCK && 
      (pLock->locktype==SHARED_LOCK || pLock->locktype==RESERVED_LOCK) ){
    assert( locktype==SHARED_LOCK );
    assert( pFile->locktype==0 );
    assert( pLock->cnt>0 );
    pFile->locktype = SHARED_LOCK;
    pLock->cnt++;
    pFile->pOpen->nLock++;
    goto end_lock;
  }


  /* A PENDING lock is needed before acquiring a SHARED lock and before
  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
  ** be released.
  */
  lock.l_len = 1L;
  lock.l_whence = SEEK_SET;
  if( locktype==SHARED_LOCK 
      || (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
  ){
    lock.l_type = (locktype==SHARED_LOCK?F_RDLCK:F_WRLCK);
    lock.l_start = PENDING_BYTE;
    s = fcntl(pFile->h, F_SETLK, &lock);
    if( s==(-1) ){
      tErrno = errno;
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
      if( IS_LOCK_ERROR(rc) ){
        pFile->lastErrno = tErrno;
      }
      goto end_lock;
    }
  }


  /* If control gets to this point, then actually go ahead and make
  ** operating system calls for the specified lock.
  */
  if( locktype==SHARED_LOCK ){
    assert( pLock->cnt==0 );
    assert( pLock->locktype==0 );

    /* Now get the read-lock */
    lock.l_start = SHARED_FIRST;
    lock.l_len = SHARED_SIZE;
    if( (s = fcntl(pFile->h, F_SETLK, &lock))==(-1) ){
      tErrno = errno;
    }







|





|
|
|





|
|
|








|
|
|

|


<
<
<
<
<
<
<
<
|




|
|









|
|
|
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|
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|










|
|

|
















|
|
|







962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000








1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
  ** The reason a single byte cannot be used instead of the 'shared byte
  ** range' is that some versions of windows do not support read-locks. By
  ** locking a random byte from a range, concurrent SHARED locks may exist
  ** even if the locking primitive used is always a write-lock.
  */
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  unixInodeInfo *pInode = pFile->pInode;
  struct flock lock;
  int s = 0;
  int tErrno = 0;

  assert( pFile );
  OSTRACE(("LOCK    %d %s was %s(%s,%d) pid=%d (unix)\n", pFile->h,
      azFileLock(eFileLock), azFileLock(pFile->eFileLock),
      azFileLock(pInode->eFileLock), pInode->nShared , getpid()));

  /* If there is already a lock of this type or more restrictive on the
  ** unixFile, do nothing. Don't use the end_lock: exit path, as
  ** unixEnterMutex() hasn't been called yet.
  */
  if( pFile->eFileLock>=eFileLock ){
    OSTRACE(("LOCK    %d %s ok (already held) (unix)\n", pFile->h,
            azFileLock(eFileLock)));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct.
  **  (1) We never move from unlocked to anything higher than shared lock.
  **  (2) SQLite never explicitly requests a pendig lock.
  **  (3) A shared lock is always held when a reserve lock is requested.
  */
  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
  assert( eFileLock!=PENDING_LOCK );
  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );

  /* This mutex is needed because pFile->pInode is shared across threads
  */
  unixEnterMutex();








  pInode = pFile->pInode;

  /* If some thread using this PID has a lock via a different unixFile*
  ** handle that precludes the requested lock, return BUSY.
  */
  if( (pFile->eFileLock!=pInode->eFileLock && 
          (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK))
  ){
    rc = SQLITE_BUSY;
    goto end_lock;
  }

  /* If a SHARED lock is requested, and some thread using this PID already
  ** has a SHARED or RESERVED lock, then increment reference counts and
  ** return SQLITE_OK.
  */
  if( eFileLock==SHARED_LOCK && 
      (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){
    assert( eFileLock==SHARED_LOCK );
    assert( pFile->eFileLock==0 );
    assert( pInode->nShared>0 );
    pFile->eFileLock = SHARED_LOCK;
    pInode->nShared++;
    pInode->nLock++;
    goto end_lock;
  }


  /* A PENDING lock is needed before acquiring a SHARED lock and before
  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
  ** be released.
  */
  lock.l_len = 1L;
  lock.l_whence = SEEK_SET;
  if( eFileLock==SHARED_LOCK 
      || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK)
  ){
    lock.l_type = (eFileLock==SHARED_LOCK?F_RDLCK:F_WRLCK);
    lock.l_start = PENDING_BYTE;
    s = fcntl(pFile->h, F_SETLK, &lock);
    if( s==(-1) ){
      tErrno = errno;
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
      if( IS_LOCK_ERROR(rc) ){
        pFile->lastErrno = tErrno;
      }
      goto end_lock;
    }
  }


  /* If control gets to this point, then actually go ahead and make
  ** operating system calls for the specified lock.
  */
  if( eFileLock==SHARED_LOCK ){
    assert( pInode->nShared==0 );
    assert( pInode->eFileLock==0 );

    /* Now get the read-lock */
    lock.l_start = SHARED_FIRST;
    lock.l_len = SHARED_SIZE;
    if( (s = fcntl(pFile->h, F_SETLK, &lock))==(-1) ){
      tErrno = errno;
    }
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
    }
    if( s==(-1) ){
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
      if( IS_LOCK_ERROR(rc) ){
        pFile->lastErrno = tErrno;
      }
    }else{
      pFile->locktype = SHARED_LOCK;
      pFile->pOpen->nLock++;
      pLock->cnt = 1;
    }
  }else if( locktype==EXCLUSIVE_LOCK && pLock->cnt>1 ){
    /* We are trying for an exclusive lock but another thread in this
    ** same process is still holding a shared lock. */
    rc = SQLITE_BUSY;
  }else{
    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
    ** assumed that there is a SHARED or greater lock on the file
    ** already.
    */
    assert( 0!=pFile->locktype );
    lock.l_type = F_WRLCK;
    switch( locktype ){
      case RESERVED_LOCK:
        lock.l_start = RESERVED_BYTE;
        break;
      case EXCLUSIVE_LOCK:
        lock.l_start = SHARED_FIRST;
        lock.l_len = SHARED_SIZE;
        break;







|
|
|

|








|

|







1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
    }
    if( s==(-1) ){
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
      if( IS_LOCK_ERROR(rc) ){
        pFile->lastErrno = tErrno;
      }
    }else{
      pFile->eFileLock = SHARED_LOCK;
      pInode->nLock++;
      pInode->nShared = 1;
    }
  }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){
    /* We are trying for an exclusive lock but another thread in this
    ** same process is still holding a shared lock. */
    rc = SQLITE_BUSY;
  }else{
    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
    ** assumed that there is a SHARED or greater lock on the file
    ** already.
    */
    assert( 0!=pFile->eFileLock );
    lock.l_type = F_WRLCK;
    switch( eFileLock ){
      case RESERVED_LOCK:
        lock.l_start = RESERVED_BYTE;
        break;
      case EXCLUSIVE_LOCK:
        lock.l_start = SHARED_FIRST;
        lock.l_len = SHARED_SIZE;
        break;
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
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1431
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1433
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1457
1458
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1460
1461
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1467
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1471
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1473
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1476
1477
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1481
1482
1483
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1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511

1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
#ifndef NDEBUG
  /* Set up the transaction-counter change checking flags when
  ** transitioning from a SHARED to a RESERVED lock.  The change
  ** from SHARED to RESERVED marks the beginning of a normal
  ** write operation (not a hot journal rollback).
  */
  if( rc==SQLITE_OK
   && pFile->locktype<=SHARED_LOCK
   && locktype==RESERVED_LOCK
  ){
    pFile->transCntrChng = 0;
    pFile->dbUpdate = 0;
    pFile->inNormalWrite = 1;
  }
#endif


  if( rc==SQLITE_OK ){
    pFile->locktype = locktype;
    pLock->locktype = locktype;
  }else if( locktype==EXCLUSIVE_LOCK ){
    pFile->locktype = PENDING_LOCK;
    pLock->locktype = PENDING_LOCK;
  }

end_lock:
  unixLeaveMutex();
  OSTRACE4("LOCK    %d %s %s (unix)\n", pFile->h, locktypeName(locktype), 
      rc==SQLITE_OK ? "ok" : "failed");
  return rc;
}

/*
** Close all file descriptors accumuated in the unixOpenCnt->pUnused list.
** If all such file descriptors are closed without error, the list is
** cleared and SQLITE_OK returned.
**
** Otherwise, if an error occurs, then successfully closed file descriptor
** entries are removed from the list, and SQLITE_IOERR_CLOSE returned. 
** not deleted and SQLITE_IOERR_CLOSE returned.
*/ 
static int closePendingFds(unixFile *pFile){
  int rc = SQLITE_OK;
  struct unixOpenCnt *pOpen = pFile->pOpen;
  UnixUnusedFd *pError = 0;
  UnixUnusedFd *p;
  UnixUnusedFd *pNext;
  for(p=pOpen->pUnused; p; p=pNext){
    pNext = p->pNext;
    if( close(p->fd) ){
      pFile->lastErrno = errno;
      rc = SQLITE_IOERR_CLOSE;
      p->pNext = pError;
      pError = p;
    }else{
      sqlite3_free(p);
    }
  }
  pOpen->pUnused = pError;
  return rc;
}

/*
** Add the file descriptor used by file handle pFile to the corresponding
** pUnused list.
*/
static void setPendingFd(unixFile *pFile){
  struct unixOpenCnt *pOpen = pFile->pOpen;
  UnixUnusedFd *p = pFile->pUnused;
  p->pNext = pOpen->pUnused;
  pOpen->pUnused = p;
  pFile->h = -1;
  pFile->pUnused = 0;
}

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
** 
** If handleNFSUnlock is true, then on downgrading an EXCLUSIVE_LOCK to SHARED
** the byte range is divided into 2 parts and the first part is unlocked then
** set to a read lock, then the other part is simply unlocked.  This works 
** around a bug in BSD NFS lockd (also seen on MacOSX 10.3+) that fails to 
** remove the write lock on a region when a read lock is set.
*/
static int _posixUnlock(sqlite3_file *id, int locktype, int handleNFSUnlock){
  unixFile *pFile = (unixFile*)id;
  struct unixLockInfo *pLock;
  struct flock lock;
  int rc = SQLITE_OK;
  int h;
  int tErrno;                      /* Error code from system call errors */

  assert( pFile );
  OSTRACE7("UNLOCK  %d %d was %d(%d,%d) pid=%d (unix)\n", pFile->h, locktype,

      pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());

  assert( locktype<=SHARED_LOCK );
  if( pFile->locktype<=locktype ){
    return SQLITE_OK;
  }
  if( CHECK_THREADID(pFile) ){
    return SQLITE_MISUSE_BKPT;
  }
  unixEnterMutex();
  h = pFile->h;
  pLock = pFile->pLock;
  assert( pLock->cnt!=0 );
  if( pFile->locktype>SHARED_LOCK ){
    assert( pLock->locktype==pFile->locktype );
    SimulateIOErrorBenign(1);
    SimulateIOError( h=(-1) )
    SimulateIOErrorBenign(0);

#ifndef NDEBUG
    /* When reducing a lock such that other processes can start
    ** reading the database file again, make sure that the







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|








|

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|

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|
>
|

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<
<
<


|
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1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
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1147
1148
1149
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1151
1152
1153
1154
1155
1156
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1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227



1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
#ifndef NDEBUG
  /* Set up the transaction-counter change checking flags when
  ** transitioning from a SHARED to a RESERVED lock.  The change
  ** from SHARED to RESERVED marks the beginning of a normal
  ** write operation (not a hot journal rollback).
  */
  if( rc==SQLITE_OK
   && pFile->eFileLock<=SHARED_LOCK
   && eFileLock==RESERVED_LOCK
  ){
    pFile->transCntrChng = 0;
    pFile->dbUpdate = 0;
    pFile->inNormalWrite = 1;
  }
#endif


  if( rc==SQLITE_OK ){
    pFile->eFileLock = eFileLock;
    pInode->eFileLock = eFileLock;
  }else if( eFileLock==EXCLUSIVE_LOCK ){
    pFile->eFileLock = PENDING_LOCK;
    pInode->eFileLock = PENDING_LOCK;
  }

end_lock:
  unixLeaveMutex();
  OSTRACE(("LOCK    %d %s %s (unix)\n", pFile->h, azFileLock(eFileLock), 
      rc==SQLITE_OK ? "ok" : "failed"));
  return rc;
}

/*
** Close all file descriptors accumuated in the unixInodeInfo->pUnused list.
** If all such file descriptors are closed without error, the list is
** cleared and SQLITE_OK returned.
**
** Otherwise, if an error occurs, then successfully closed file descriptor
** entries are removed from the list, and SQLITE_IOERR_CLOSE returned. 
** not deleted and SQLITE_IOERR_CLOSE returned.
*/ 
static int closePendingFds(unixFile *pFile){
  int rc = SQLITE_OK;
  unixInodeInfo *pInode = pFile->pInode;
  UnixUnusedFd *pError = 0;
  UnixUnusedFd *p;
  UnixUnusedFd *pNext;
  for(p=pInode->pUnused; p; p=pNext){
    pNext = p->pNext;
    if( close(p->fd) ){
      pFile->lastErrno = errno;
      rc = SQLITE_IOERR_CLOSE;
      p->pNext = pError;
      pError = p;
    }else{
      sqlite3_free(p);
    }
  }
  pInode->pUnused = pError;
  return rc;
}

/*
** Add the file descriptor used by file handle pFile to the corresponding
** pUnused list.
*/
static void setPendingFd(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  UnixUnusedFd *p = pFile->pUnused;
  p->pNext = pInode->pUnused;
  pInode->pUnused = p;
  pFile->h = -1;
  pFile->pUnused = 0;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
** 
** If handleNFSUnlock is true, then on downgrading an EXCLUSIVE_LOCK to SHARED
** the byte range is divided into 2 parts and the first part is unlocked then
** set to a read lock, then the other part is simply unlocked.  This works 
** around a bug in BSD NFS lockd (also seen on MacOSX 10.3+) that fails to 
** remove the write lock on a region when a read lock is set.
*/
static int _posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
  unixFile *pFile = (unixFile*)id;
  unixInodeInfo *pInode;
  struct flock lock;
  int rc = SQLITE_OK;
  int h;
  int tErrno;                      /* Error code from system call errors */

  assert( pFile );
  OSTRACE(("UNLOCK  %d %d was %d(%d,%d) pid=%d (unix)\n", pFile->h, eFileLock,
      pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared,
      getpid()));

  assert( eFileLock<=SHARED_LOCK );
  if( pFile->eFileLock<=eFileLock ){
    return SQLITE_OK;
  }



  unixEnterMutex();
  h = pFile->h;
  pInode = pFile->pInode;
  assert( pInode->nShared!=0 );
  if( pFile->eFileLock>SHARED_LOCK ){
    assert( pInode->eFileLock==pFile->eFileLock );
    SimulateIOErrorBenign(1);
    SimulateIOError( h=(-1) )
    SimulateIOErrorBenign(0);

#ifndef NDEBUG
    /* When reducing a lock such that other processes can start
    ** reading the database file again, make sure that the
1550
1551
1552
1553
1554
1555
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1557
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1559
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1561
1562
1563
1564
    ** the lock in 2 blocks, so that part of the range will be covered by a 
    ** write lock until the rest is covered by a read lock:
    **  1:   [WWWWW]
    **  2:   [....W]
    **  3:   [RRRRW]
    **  4:   [RRRR.]
    */
    if( locktype==SHARED_LOCK ){
      if( handleNFSUnlock ){
        off_t divSize = SHARED_SIZE - 1;
        
        lock.l_type = F_UNLCK;
        lock.l_whence = SEEK_SET;
        lock.l_start = SHARED_FIRST;
        lock.l_len = divSize;







|







1257
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1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
    ** the lock in 2 blocks, so that part of the range will be covered by a 
    ** write lock until the rest is covered by a read lock:
    **  1:   [WWWWW]
    **  2:   [....W]
    **  3:   [RRRRW]
    **  4:   [RRRR.]
    */
    if( eFileLock==SHARED_LOCK ){
      if( handleNFSUnlock ){
        off_t divSize = SHARED_SIZE - 1;
        
        lock.l_type = F_UNLCK;
        lock.l_whence = SEEK_SET;
        lock.l_start = SHARED_FIRST;
        lock.l_len = divSize;
1610
1611
1612
1613
1614
1615
1616
1617
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      }
    }
    lock.l_type = F_UNLCK;
    lock.l_whence = SEEK_SET;
    lock.l_start = PENDING_BYTE;
    lock.l_len = 2L;  assert( PENDING_BYTE+1==RESERVED_BYTE );
    if( fcntl(h, F_SETLK, &lock)!=(-1) ){
      pLock->locktype = SHARED_LOCK;
    }else{
      tErrno = errno;
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
      if( IS_LOCK_ERROR(rc) ){
        pFile->lastErrno = tErrno;
      }
      goto end_unlock;
    }
  }
  if( locktype==NO_LOCK ){
    struct unixOpenCnt *pOpen;

    /* Decrement the shared lock counter.  Release the lock using an
    ** OS call only when all threads in this same process have released
    ** the lock.
    */
    pLock->cnt--;
    if( pLock->cnt==0 ){
      lock.l_type = F_UNLCK;
      lock.l_whence = SEEK_SET;
      lock.l_start = lock.l_len = 0L;
      SimulateIOErrorBenign(1);
      SimulateIOError( h=(-1) )
      SimulateIOErrorBenign(0);
      if( fcntl(h, F_SETLK, &lock)!=(-1) ){
        pLock->locktype = NO_LOCK;
      }else{
        tErrno = errno;
        rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
        if( IS_LOCK_ERROR(rc) ){
          pFile->lastErrno = tErrno;
        }
        pLock->locktype = NO_LOCK;
        pFile->locktype = NO_LOCK;
      }
    }

    /* Decrement the count of locks against this same file.  When the
    ** count reaches zero, close any other file descriptors whose close
    ** was deferred because of outstanding locks.
    */
    pOpen = pFile->pOpen;
    pOpen->nLock--;
    assert( pOpen->nLock>=0 );
    if( pOpen->nLock==0 ){
      int rc2 = closePendingFds(pFile);
      if( rc==SQLITE_OK ){
        rc = rc2;
      }
    }
  }
	
end_unlock:
  unixLeaveMutex();
  if( rc==SQLITE_OK ) pFile->locktype = locktype;
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int unixUnlock(sqlite3_file *id, int locktype){
  return _posixUnlock(id, locktype, 0);
}

/*
** This function performs the parts of the "close file" operation 
** common to all locking schemes. It closes the directory and file
** handles, if they are valid, and sets all fields of the unixFile
** structure to 0.







|









|
<
<




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|






|
|







<
|
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|









|




|





|
|







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      }
    }
    lock.l_type = F_UNLCK;
    lock.l_whence = SEEK_SET;
    lock.l_start = PENDING_BYTE;
    lock.l_len = 2L;  assert( PENDING_BYTE+1==RESERVED_BYTE );
    if( fcntl(h, F_SETLK, &lock)!=(-1) ){
      pInode->eFileLock = SHARED_LOCK;
    }else{
      tErrno = errno;
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
      if( IS_LOCK_ERROR(rc) ){
        pFile->lastErrno = tErrno;
      }
      goto end_unlock;
    }
  }
  if( eFileLock==NO_LOCK ){


    /* Decrement the shared lock counter.  Release the lock using an
    ** OS call only when all threads in this same process have released
    ** the lock.
    */
    pInode->nShared--;
    if( pInode->nShared==0 ){
      lock.l_type = F_UNLCK;
      lock.l_whence = SEEK_SET;
      lock.l_start = lock.l_len = 0L;
      SimulateIOErrorBenign(1);
      SimulateIOError( h=(-1) )
      SimulateIOErrorBenign(0);
      if( fcntl(h, F_SETLK, &lock)!=(-1) ){
        pInode->eFileLock = NO_LOCK;
      }else{
        tErrno = errno;
        rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
        if( IS_LOCK_ERROR(rc) ){
          pFile->lastErrno = tErrno;
        }
        pInode->eFileLock = NO_LOCK;
        pFile->eFileLock = NO_LOCK;
      }
    }

    /* Decrement the count of locks against this same file.  When the
    ** count reaches zero, close any other file descriptors whose close
    ** was deferred because of outstanding locks.
    */

    pInode->nLock--;
    assert( pInode->nLock>=0 );
    if( pInode->nLock==0 ){
      int rc2 = closePendingFds(pFile);
      if( rc==SQLITE_OK ){
        rc = rc2;
      }
    }
  }
	
end_unlock:
  unixLeaveMutex();
  if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock;
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int unixUnlock(sqlite3_file *id, int eFileLock){
  return _posixUnlock(id, eFileLock, 0);
}

/*
** This function performs the parts of the "close file" operation 
** common to all locking schemes. It closes the directory and file
** handles, if they are valid, and sets all fields of the unixFile
** structure to 0.
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      if( pFile->isDelete ){
        unlink(pFile->pId->zCanonicalName);
      }
      vxworksReleaseFileId(pFile->pId);
      pFile->pId = 0;
    }
#endif
    OSTRACE2("CLOSE   %-3d\n", pFile->h);
    OpenCounter(-1);
    sqlite3_free(pFile->pUnused);
    memset(pFile, 0, sizeof(unixFile));
  }
  return SQLITE_OK;
}

/*
** Close a file.
*/
static int unixClose(sqlite3_file *id){
  int rc = SQLITE_OK;
  if( id ){
    unixFile *pFile = (unixFile *)id;
    unixUnlock(id, NO_LOCK);
    unixEnterMutex();
    if( pFile->pOpen && pFile->pOpen->nLock ){
      /* If there are outstanding locks, do not actually close the file just
      ** yet because that would clear those locks.  Instead, add the file
      ** descriptor to pOpen->pUnused list.  It will be automatically closed 
      ** when the last lock is cleared.
      */
      setPendingFd(pFile);
    }
    releaseLockInfo(pFile->pLock);
    releaseOpenCnt(pFile->pOpen);
    rc = closeUnixFile(id);
    unixLeaveMutex();
  }
  return rc;
}

/************** End of the posix advisory lock implementation *****************







|


|













|


|




|
<







1422
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1454

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      if( pFile->isDelete ){
        unlink(pFile->pId->zCanonicalName);
      }
      vxworksReleaseFileId(pFile->pId);
      pFile->pId = 0;
    }
#endif
    OSTRACE(("CLOSE   %-3d\n", pFile->h);
    OpenCounter(-1);
    sqlite3_free(pFile->pUnused);
    memset(pFile, 0, sizeof(unixFile)));
  }
  return SQLITE_OK;
}

/*
** Close a file.
*/
static int unixClose(sqlite3_file *id){
  int rc = SQLITE_OK;
  if( id ){
    unixFile *pFile = (unixFile *)id;
    unixUnlock(id, NO_LOCK);
    unixEnterMutex();
    if( pFile->pInode && pFile->pInode->nLock ){
      /* If there are outstanding locks, do not actually close the file just
      ** yet because that would clear those locks.  Instead, add the file
      ** descriptor to pInode->pUnused list.  It will be automatically closed 
      ** when the last lock is cleared.
      */
      setPendingFd(pFile);
    }
    releaseInodeInfo(pFile->pInode);

    rc = closeUnixFile(id);
    unixLeaveMutex();
  }
  return rc;
}

/************** End of the posix advisory lock implementation *****************
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  unixFile *pFile = (unixFile*)id;

  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
  
  assert( pFile );

  /* Check if a thread in this process holds such a lock */
  if( pFile->locktype>SHARED_LOCK ){
    /* Either this connection or some other connection in the same process
    ** holds a lock on the file.  No need to check further. */
    reserved = 1;
  }else{
    /* The lock is held if and only if the lockfile exists */
    const char *zLockFile = (const char*)pFile->lockingContext;
    reserved = access(zLockFile, 0)==0;
  }
  OSTRACE4("TEST WR-LOCK %d %d %d (dotlock)\n", pFile->h, rc, reserved);
  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**







|








|





|







1546
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  unixFile *pFile = (unixFile*)id;

  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
  
  assert( pFile );

  /* Check if a thread in this process holds such a lock */
  if( pFile->eFileLock>SHARED_LOCK ){
    /* Either this connection or some other connection in the same process
    ** holds a lock on the file.  No need to check further. */
    reserved = 1;
  }else{
    /* The lock is held if and only if the lockfile exists */
    const char *zLockFile = (const char*)pFile->lockingContext;
    reserved = access(zLockFile, 0)==0;
  }
  OSTRACE(("TEST WR-LOCK %d %d %d (dotlock)\n", pFile->h, rc, reserved));
  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter eFileLock - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**
1884
1885
1886
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1890
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1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
**
** With dotfile locking, we really only support state (4): EXCLUSIVE.
** But we track the other locking levels internally.
*/
static int dotlockLock(sqlite3_file *id, int locktype) {
  unixFile *pFile = (unixFile*)id;
  int fd;
  char *zLockFile = (char *)pFile->lockingContext;
  int rc = SQLITE_OK;


  /* If we have any lock, then the lock file already exists.  All we have
  ** to do is adjust our internal record of the lock level.
  */
  if( pFile->locktype > NO_LOCK ){
    pFile->locktype = locktype;
#if !OS_VXWORKS
    /* Always update the timestamp on the old file */
    utimes(zLockFile, NULL);
#endif
    return SQLITE_OK;
  }
  







|









|
|







1587
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1600
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1604
1605
1606
1607
1608
1609
1610
1611
1612
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
**
** With dotfile locking, we really only support state (4): EXCLUSIVE.
** But we track the other locking levels internally.
*/
static int dotlockLock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  int fd;
  char *zLockFile = (char *)pFile->lockingContext;
  int rc = SQLITE_OK;


  /* If we have any lock, then the lock file already exists.  All we have
  ** to do is adjust our internal record of the lock level.
  */
  if( pFile->eFileLock > NO_LOCK ){
    pFile->eFileLock = eFileLock;
#if !OS_VXWORKS
    /* Always update the timestamp on the old file */
    utimes(zLockFile, NULL);
#endif
    return SQLITE_OK;
  }
  
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1984
1985
1986
  } 
  if( close(fd) ){
    pFile->lastErrno = errno;
    rc = SQLITE_IOERR_CLOSE;
  }
  
  /* got it, set the type and return ok */
  pFile->locktype = locktype;
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
**
** When the locking level reaches NO_LOCK, delete the lock file.
*/
static int dotlockUnlock(sqlite3_file *id, int locktype) {
  unixFile *pFile = (unixFile*)id;
  char *zLockFile = (char *)pFile->lockingContext;

  assert( pFile );
  OSTRACE5("UNLOCK  %d %d was %d pid=%d (dotlock)\n", pFile->h, locktype,
	   pFile->locktype, getpid());
  assert( locktype<=SHARED_LOCK );
  
  /* no-op if possible */
  if( pFile->locktype==locktype ){
    return SQLITE_OK;
  }

  /* To downgrade to shared, simply update our internal notion of the
  ** lock state.  No need to mess with the file on disk.
  */
  if( locktype==SHARED_LOCK ){
    pFile->locktype = SHARED_LOCK;
    return SQLITE_OK;
  }
  
  /* To fully unlock the database, delete the lock file */
  assert( locktype==NO_LOCK );
  if( unlink(zLockFile) ){
    int rc = 0;
    int tErrno = errno;
    if( ENOENT != tErrno ){
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
    }
    if( IS_LOCK_ERROR(rc) ){
      pFile->lastErrno = tErrno;
    }
    return rc; 
  }
  pFile->locktype = NO_LOCK;
  return SQLITE_OK;
}

/*
** Close a file.  Make sure the lock has been released before closing.
*/
static int dotlockClose(sqlite3_file *id) {







|




|







|




|
|
|


|






|
|




|











|







1627
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1634
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1638
1639
1640
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1677
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1681
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1684
1685
1686
1687
1688
1689
  } 
  if( close(fd) ){
    pFile->lastErrno = errno;
    rc = SQLITE_IOERR_CLOSE;
  }
  
  /* got it, set the type and return ok */
  pFile->eFileLock = eFileLock;
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
**
** When the locking level reaches NO_LOCK, delete the lock file.
*/
static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  char *zLockFile = (char *)pFile->lockingContext;

  assert( pFile );
  OSTRACE(("UNLOCK  %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock,
	   pFile->eFileLock, getpid()));
  assert( eFileLock<=SHARED_LOCK );
  
  /* no-op if possible */
  if( pFile->eFileLock==eFileLock ){
    return SQLITE_OK;
  }

  /* To downgrade to shared, simply update our internal notion of the
  ** lock state.  No need to mess with the file on disk.
  */
  if( eFileLock==SHARED_LOCK ){
    pFile->eFileLock = SHARED_LOCK;
    return SQLITE_OK;
  }
  
  /* To fully unlock the database, delete the lock file */
  assert( eFileLock==NO_LOCK );
  if( unlink(zLockFile) ){
    int rc = 0;
    int tErrno = errno;
    if( ENOENT != tErrno ){
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
    }
    if( IS_LOCK_ERROR(rc) ){
      pFile->lastErrno = tErrno;
    }
    return rc; 
  }
  pFile->eFileLock = NO_LOCK;
  return SQLITE_OK;
}

/*
** Close a file.  Make sure the lock has been released before closing.
*/
static int dotlockClose(sqlite3_file *id) {
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2031
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2036
2037
2038
2039
  unixFile *pFile = (unixFile*)id;
  
  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
  
  assert( pFile );
  
  /* Check if a thread in this process holds such a lock */
  if( pFile->locktype>SHARED_LOCK ){
    reserved = 1;
  }
  
  /* Otherwise see if some other process holds it. */
  if( !reserved ){
    /* attempt to get the lock */
    int lrc = flock(pFile->h, LOCK_EX | LOCK_NB);







|







1728
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1742
  unixFile *pFile = (unixFile*)id;
  
  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
  
  assert( pFile );
  
  /* Check if a thread in this process holds such a lock */
  if( pFile->eFileLock>SHARED_LOCK ){
    reserved = 1;
  }
  
  /* Otherwise see if some other process holds it. */
  if( !reserved ){
    /* attempt to get the lock */
    int lrc = flock(pFile->h, LOCK_EX | LOCK_NB);
2056
2057
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      lrc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); 
      if( IS_LOCK_ERROR(lrc) ){
        pFile->lastErrno = tErrno;
        rc = lrc;
      }
    }
  }
  OSTRACE4("TEST WR-LOCK %d %d %d (flock)\n", pFile->h, rc, reserved);

#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
  if( (rc & SQLITE_IOERR) == SQLITE_IOERR ){
    rc = SQLITE_OK;
    reserved=1;
  }
#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**







|












|







1759
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1786
      lrc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); 
      if( IS_LOCK_ERROR(lrc) ){
        pFile->lastErrno = tErrno;
        rc = lrc;
      }
    }
  }
  OSTRACE(("TEST WR-LOCK %d %d %d (flock)\n", pFile->h, rc, reserved));

#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
  if( (rc & SQLITE_IOERR) == SQLITE_IOERR ){
    rc = SQLITE_OK;
    reserved=1;
  }
#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter eFileLock - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**
2097
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2178
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2181
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2184
2185
2186
2187
2188
2189
2190
** lock states in the sqlite3_file structure, but all locks SHARED or
** above are really EXCLUSIVE locks and exclude all other processes from
** access the file.
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int flockLock(sqlite3_file *id, int locktype) {
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;

  assert( pFile );

  /* if we already have a lock, it is exclusive.  
  ** Just adjust level and punt on outta here. */
  if (pFile->locktype > NO_LOCK) {
    pFile->locktype = locktype;
    return SQLITE_OK;
  }
  
  /* grab an exclusive lock */
  
  if (flock(pFile->h, LOCK_EX | LOCK_NB)) {
    int tErrno = errno;
    /* didn't get, must be busy */
    rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
    if( IS_LOCK_ERROR(rc) ){
      pFile->lastErrno = tErrno;
    }
  } else {
    /* got it, set the type and return ok */
    pFile->locktype = locktype;
  }
  OSTRACE4("LOCK    %d %s %s (flock)\n", pFile->h, locktypeName(locktype), 
           rc==SQLITE_OK ? "ok" : "failed");
#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
  if( (rc & SQLITE_IOERR) == SQLITE_IOERR ){
    rc = SQLITE_BUSY;
  }
#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
  return rc;
}


/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int flockUnlock(sqlite3_file *id, int locktype) {
  unixFile *pFile = (unixFile*)id;
  
  assert( pFile );
  OSTRACE5("UNLOCK  %d %d was %d pid=%d (flock)\n", pFile->h, locktype,
           pFile->locktype, getpid());
  assert( locktype<=SHARED_LOCK );
  
  /* no-op if possible */
  if( pFile->locktype==locktype ){
    return SQLITE_OK;
  }
  
  /* shared can just be set because we always have an exclusive */
  if (locktype==SHARED_LOCK) {
    pFile->locktype = locktype;
    return SQLITE_OK;
  }
  
  /* no, really, unlock. */
  int rc = flock(pFile->h, LOCK_UN);
  if (rc) {
    int r, tErrno = errno;
    r = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
    if( IS_LOCK_ERROR(r) ){
      pFile->lastErrno = tErrno;
    }
#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
    if( (r & SQLITE_IOERR) == SQLITE_IOERR ){
      r = SQLITE_BUSY;
    }
#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
    
    return r;
  } else {
    pFile->locktype = NO_LOCK;
    return SQLITE_OK;
  }
}

/*
** Close a file.
*/







|







|
|














|

|
|










|





|



|
|
|


|




|
|



















|







1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
** lock states in the sqlite3_file structure, but all locks SHARED or
** above are really EXCLUSIVE locks and exclude all other processes from
** access the file.
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int flockLock(sqlite3_file *id, int eFileLock) {
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;

  assert( pFile );

  /* if we already have a lock, it is exclusive.  
  ** Just adjust level and punt on outta here. */
  if (pFile->eFileLock > NO_LOCK) {
    pFile->eFileLock = eFileLock;
    return SQLITE_OK;
  }
  
  /* grab an exclusive lock */
  
  if (flock(pFile->h, LOCK_EX | LOCK_NB)) {
    int tErrno = errno;
    /* didn't get, must be busy */
    rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
    if( IS_LOCK_ERROR(rc) ){
      pFile->lastErrno = tErrno;
    }
  } else {
    /* got it, set the type and return ok */
    pFile->eFileLock = eFileLock;
  }
  OSTRACE(("LOCK    %d %s %s (flock)\n", pFile->h, azFileLock(eFileLock), 
           rc==SQLITE_OK ? "ok" : "failed"));
#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
  if( (rc & SQLITE_IOERR) == SQLITE_IOERR ){
    rc = SQLITE_BUSY;
  }
#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
  return rc;
}


/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int flockUnlock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  
  assert( pFile );
  OSTRACE(("UNLOCK  %d %d was %d pid=%d (flock)\n", pFile->h, eFileLock,
           pFile->eFileLock, getpid()));
  assert( eFileLock<=SHARED_LOCK );
  
  /* no-op if possible */
  if( pFile->eFileLock==eFileLock ){
    return SQLITE_OK;
  }
  
  /* shared can just be set because we always have an exclusive */
  if (eFileLock==SHARED_LOCK) {
    pFile->eFileLock = eFileLock;
    return SQLITE_OK;
  }
  
  /* no, really, unlock. */
  int rc = flock(pFile->h, LOCK_UN);
  if (rc) {
    int r, tErrno = errno;
    r = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
    if( IS_LOCK_ERROR(r) ){
      pFile->lastErrno = tErrno;
    }
#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
    if( (r & SQLITE_IOERR) == SQLITE_IOERR ){
      r = SQLITE_BUSY;
    }
#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
    
    return r;
  } else {
    pFile->eFileLock = NO_LOCK;
    return SQLITE_OK;
  }
}

/*
** Close a file.
*/
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
  unixFile *pFile = (unixFile*)id;

  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
  
  assert( pFile );

  /* Check if a thread in this process holds such a lock */
  if( pFile->locktype>SHARED_LOCK ){
    reserved = 1;
  }
  
  /* Otherwise see if some other process holds it. */
  if( !reserved ){
    sem_t *pSem = pFile->pOpen->pSem;
    struct stat statBuf;

    if( sem_trywait(pSem)==-1 ){
      int tErrno = errno;
      if( EAGAIN != tErrno ){
        rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK);
        pFile->lastErrno = tErrno;
      } else {
        /* someone else has the lock when we are in NO_LOCK */
        reserved = (pFile->locktype < SHARED_LOCK);
      }
    }else{
      /* we could have it if we want it */
      sem_post(pSem);
    }
  }
  OSTRACE4("TEST WR-LOCK %d %d %d (sem)\n", pFile->h, rc, reserved);

  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**







|





|









|






|






|







1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
  unixFile *pFile = (unixFile*)id;

  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
  
  assert( pFile );

  /* Check if a thread in this process holds such a lock */
  if( pFile->eFileLock>SHARED_LOCK ){
    reserved = 1;
  }
  
  /* Otherwise see if some other process holds it. */
  if( !reserved ){
    sem_t *pSem = pFile->pInode->pSem;
    struct stat statBuf;

    if( sem_trywait(pSem)==-1 ){
      int tErrno = errno;
      if( EAGAIN != tErrno ){
        rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK);
        pFile->lastErrno = tErrno;
      } else {
        /* someone else has the lock when we are in NO_LOCK */
        reserved = (pFile->eFileLock < SHARED_LOCK);
      }
    }else{
      /* we could have it if we want it */
      sem_post(pSem);
    }
  }
  OSTRACE(("TEST WR-LOCK %d %d %d (sem)\n", pFile->h, rc, reserved));

  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter eFileLock - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
** lock states in the sqlite3_file structure, but all locks SHARED or
** above are really EXCLUSIVE locks and exclude all other processes from
** access the file.
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int semLock(sqlite3_file *id, int locktype) {
  unixFile *pFile = (unixFile*)id;
  int fd;
  sem_t *pSem = pFile->pOpen->pSem;
  int rc = SQLITE_OK;

  /* if we already have a lock, it is exclusive.  
  ** Just adjust level and punt on outta here. */
  if (pFile->locktype > NO_LOCK) {
    pFile->locktype = locktype;
    rc = SQLITE_OK;
    goto sem_end_lock;
  }
  
  /* lock semaphore now but bail out when already locked. */
  if( sem_trywait(pSem)==-1 ){
    rc = SQLITE_BUSY;
    goto sem_end_lock;
  }

  /* got it, set the type and return ok */
  pFile->locktype = locktype;

 sem_end_lock:
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int semUnlock(sqlite3_file *id, int locktype) {
  unixFile *pFile = (unixFile*)id;
  sem_t *pSem = pFile->pOpen->pSem;

  assert( pFile );
  assert( pSem );
  OSTRACE5("UNLOCK  %d %d was %d pid=%d (sem)\n", pFile->h, locktype,
	   pFile->locktype, getpid());
  assert( locktype<=SHARED_LOCK );
  
  /* no-op if possible */
  if( pFile->locktype==locktype ){
    return SQLITE_OK;
  }
  
  /* shared can just be set because we always have an exclusive */
  if (locktype==SHARED_LOCK) {
    pFile->locktype = locktype;
    return SQLITE_OK;
  }
  
  /* no, really unlock. */
  if ( sem_post(pSem)==-1 ) {
    int rc, tErrno = errno;
    rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
    if( IS_LOCK_ERROR(rc) ){
      pFile->lastErrno = tErrno;
    }
    return rc; 
  }
  pFile->locktype = NO_LOCK;
  return SQLITE_OK;
}

/*
 ** Close a file.
 */
static int semClose(sqlite3_file *id) {
  if( id ){
    unixFile *pFile = (unixFile*)id;
    semUnlock(id, NO_LOCK);
    assert( pFile );
    unixEnterMutex();
    releaseLockInfo(pFile->pLock);
    releaseOpenCnt(pFile->pOpen);
    unixLeaveMutex();
    closeUnixFile(id);
  }
  return SQLITE_OK;
}

#endif /* OS_VXWORKS */







|


|




|
|











|






|





|

|



|
|
|


|




|
|












|












|
<







1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
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2027
2028
2029
2030
2031
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2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069

2070
2071
2072
2073
2074
2075
2076
** lock states in the sqlite3_file structure, but all locks SHARED or
** above are really EXCLUSIVE locks and exclude all other processes from
** access the file.
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int semLock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  int fd;
  sem_t *pSem = pFile->pInode->pSem;
  int rc = SQLITE_OK;

  /* if we already have a lock, it is exclusive.  
  ** Just adjust level and punt on outta here. */
  if (pFile->eFileLock > NO_LOCK) {
    pFile->eFileLock = eFileLock;
    rc = SQLITE_OK;
    goto sem_end_lock;
  }
  
  /* lock semaphore now but bail out when already locked. */
  if( sem_trywait(pSem)==-1 ){
    rc = SQLITE_BUSY;
    goto sem_end_lock;
  }

  /* got it, set the type and return ok */
  pFile->eFileLock = eFileLock;

 sem_end_lock:
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int semUnlock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  sem_t *pSem = pFile->pInode->pSem;

  assert( pFile );
  assert( pSem );
  OSTRACE(("UNLOCK  %d %d was %d pid=%d (sem)\n", pFile->h, eFileLock,
	   pFile->eFileLock, getpid()));
  assert( eFileLock<=SHARED_LOCK );
  
  /* no-op if possible */
  if( pFile->eFileLock==eFileLock ){
    return SQLITE_OK;
  }
  
  /* shared can just be set because we always have an exclusive */
  if (eFileLock==SHARED_LOCK) {
    pFile->eFileLock = eFileLock;
    return SQLITE_OK;
  }
  
  /* no, really unlock. */
  if ( sem_post(pSem)==-1 ) {
    int rc, tErrno = errno;
    rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
    if( IS_LOCK_ERROR(rc) ){
      pFile->lastErrno = tErrno;
    }
    return rc; 
  }
  pFile->eFileLock = NO_LOCK;
  return SQLITE_OK;
}

/*
 ** Close a file.
 */
static int semClose(sqlite3_file *id) {
  if( id ){
    unixFile *pFile = (unixFile*)id;
    semUnlock(id, NO_LOCK);
    assert( pFile );
    unixEnterMutex();
    releaseLockInfo(pFile->pInode);

    unixLeaveMutex();
    closeUnixFile(id);
  }
  return SQLITE_OK;
}

#endif /* OS_VXWORKS */
2429
2430
2431
2432
2433
2434
2435
2436
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2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
  
  pb.unLockFlag = setLockFlag ? 0 : 1;
  pb.startEndFlag = 0;
  pb.offset = offset;
  pb.length = length; 
  pb.fd = pFile->h;
  
  OSTRACE6("AFPSETLOCK [%s] for %d%s in range %llx:%llx\n", 
    (setLockFlag?"ON":"OFF"), pFile->h, (pb.fd==-1?"[testval-1]":""),
    offset, length);
  err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0);
  if ( err==-1 ) {
    int rc;
    int tErrno = errno;
    OSTRACE4("AFPSETLOCK failed to fsctl() '%s' %d %s\n",
             path, tErrno, strerror(tErrno));
#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS
    rc = SQLITE_BUSY;
#else
    rc = sqliteErrorFromPosixError(tErrno,
                    setLockFlag ? SQLITE_IOERR_LOCK : SQLITE_IOERR_UNLOCK);
#endif /* SQLITE_IGNORE_AFP_LOCK_ERRORS */
    if( IS_LOCK_ERROR(rc) ){







|

|




|
|







2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
  
  pb.unLockFlag = setLockFlag ? 0 : 1;
  pb.startEndFlag = 0;
  pb.offset = offset;
  pb.length = length; 
  pb.fd = pFile->h;
  
  OSTRACE(("AFPSETLOCK [%s] for %d%s in range %llx:%llx\n", 
    (setLockFlag?"ON":"OFF"), pFile->h, (pb.fd==-1?"[testval-1]":""),
    offset, length));
  err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0);
  if ( err==-1 ) {
    int rc;
    int tErrno = errno;
    OSTRACE(("AFPSETLOCK failed to fsctl() '%s' %d %s\n",
             path, tErrno, strerror(tErrno)));
#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS
    rc = SQLITE_BUSY;
#else
    rc = sqliteErrorFromPosixError(tErrno,
                    setLockFlag ? SQLITE_IOERR_LOCK : SQLITE_IOERR_UNLOCK);
#endif /* SQLITE_IGNORE_AFP_LOCK_ERRORS */
    if( IS_LOCK_ERROR(rc) ){
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
  
  assert( pFile );
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  if( context->reserved ){
    *pResOut = 1;
    return SQLITE_OK;
  }
  unixEnterMutex(); /* Because pFile->pLock is shared across threads */
  
  /* Check if a thread in this process holds such a lock */
  if( pFile->pLock->locktype>SHARED_LOCK ){
    reserved = 1;
  }
  
  /* Otherwise see if some other process holds it.
   */
  if( !reserved ){
    /* lock the RESERVED byte */







|


|







2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
  
  assert( pFile );
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  if( context->reserved ){
    *pResOut = 1;
    return SQLITE_OK;
  }
  unixEnterMutex(); /* Because pFile->pInode is shared across threads */
  
  /* Check if a thread in this process holds such a lock */
  if( pFile->pInode->eFileLock>SHARED_LOCK ){
    reserved = 1;
  }
  
  /* Otherwise see if some other process holds it.
   */
  if( !reserved ){
    /* lock the RESERVED byte */
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
    }
    if( IS_LOCK_ERROR(lrc) ){
      rc=lrc;
    }
  }
  
  unixLeaveMutex();
  OSTRACE4("TEST WR-LOCK %d %d %d (afp)\n", pFile->h, rc, reserved);
  
  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**







|






|







2200
2201
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2203
2204
2205
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2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
    }
    if( IS_LOCK_ERROR(lrc) ){
      rc=lrc;
    }
  }
  
  unixLeaveMutex();
  OSTRACE(("TEST WR-LOCK %d %d %d (afp)\n", pFile->h, rc, reserved));
  
  *pResOut = reserved;
  return rc;
}

/*
** Lock the file with the lock specified by parameter eFileLock - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**
2528
2529
2530
2531
2532
2533
2534
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2537
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2641
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2649
2650
2651
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2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
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2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736

2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
**    SHARED -> (PENDING) -> EXCLUSIVE
**    RESERVED -> (PENDING) -> EXCLUSIVE
**    PENDING -> EXCLUSIVE
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int afpLock(sqlite3_file *id, int locktype){
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  struct unixLockInfo *pLock = pFile->pLock;
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  
  assert( pFile );
  OSTRACE7("LOCK    %d %s was %s(%s,%d) pid=%d (afp)\n", pFile->h,
           locktypeName(locktype), locktypeName(pFile->locktype),
           locktypeName(pLock->locktype), pLock->cnt , getpid());

  /* If there is already a lock of this type or more restrictive on the
  ** unixFile, do nothing. Don't use the afp_end_lock: exit path, as
  ** unixEnterMutex() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){
    OSTRACE3("LOCK    %d %s ok (already held) (afp)\n", pFile->h,
           locktypeName(locktype));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct
  **  (1) We never move from unlocked to anything higher than shared lock.
  **  (2) SQLite never explicitly requests a pendig lock.
  **  (3) A shared lock is always held when a reserve lock is requested.
  */
  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
  assert( locktype!=PENDING_LOCK );
  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
  
  /* This mutex is needed because pFile->pLock is shared across threads
  */
  unixEnterMutex();

  /* Make sure the current thread owns the pFile.
  */
  rc = transferOwnership(pFile);
  if( rc!=SQLITE_OK ){
    unixLeaveMutex();
    return rc;
  }
  pLock = pFile->pLock;

  /* If some thread using this PID has a lock via a different unixFile*
  ** handle that precludes the requested lock, return BUSY.
  */
  if( (pFile->locktype!=pLock->locktype && 
       (pLock->locktype>=PENDING_LOCK || locktype>SHARED_LOCK))
     ){
    rc = SQLITE_BUSY;
    goto afp_end_lock;
  }
  
  /* If a SHARED lock is requested, and some thread using this PID already
  ** has a SHARED or RESERVED lock, then increment reference counts and
  ** return SQLITE_OK.
  */
  if( locktype==SHARED_LOCK && 
     (pLock->locktype==SHARED_LOCK || pLock->locktype==RESERVED_LOCK) ){
    assert( locktype==SHARED_LOCK );
    assert( pFile->locktype==0 );
    assert( pLock->cnt>0 );
    pFile->locktype = SHARED_LOCK;
    pLock->cnt++;
    pFile->pOpen->nLock++;
    goto afp_end_lock;
  }
    
  /* A PENDING lock is needed before acquiring a SHARED lock and before
  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
  ** be released.
  */
  if( locktype==SHARED_LOCK 
      || (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
  ){
    int failed;
    failed = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 1);
    if (failed) {
      rc = failed;
      goto afp_end_lock;
    }
  }
  
  /* If control gets to this point, then actually go ahead and make
  ** operating system calls for the specified lock.
  */
  if( locktype==SHARED_LOCK ){
    int lrc1, lrc2, lrc1Errno;
    long lk, mask;
    
    assert( pLock->cnt==0 );
    assert( pLock->locktype==0 );
        
    mask = (sizeof(long)==8) ? LARGEST_INT64 : 0x7fffffff;
    /* Now get the read-lock SHARED_LOCK */
    /* note that the quality of the randomness doesn't matter that much */
    lk = random(); 
    pLock->sharedByte = (lk & mask)%(SHARED_SIZE - 1);
    lrc1 = afpSetLock(context->dbPath, pFile, 
          SHARED_FIRST+pLock->sharedByte, 1, 1);
    if( IS_LOCK_ERROR(lrc1) ){
      lrc1Errno = pFile->lastErrno;
    }
    /* Drop the temporary PENDING lock */
    lrc2 = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
    
    if( IS_LOCK_ERROR(lrc1) ) {
      pFile->lastErrno = lrc1Errno;
      rc = lrc1;
      goto afp_end_lock;
    } else if( IS_LOCK_ERROR(lrc2) ){
      rc = lrc2;
      goto afp_end_lock;
    } else if( lrc1 != SQLITE_OK ) {
      rc = lrc1;
    } else {
      pFile->locktype = SHARED_LOCK;
      pFile->pOpen->nLock++;
      pLock->cnt = 1;
    }
  }else if( locktype==EXCLUSIVE_LOCK && pLock->cnt>1 ){
    /* We are trying for an exclusive lock but another thread in this
     ** same process is still holding a shared lock. */
    rc = SQLITE_BUSY;
  }else{
    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
    ** assumed that there is a SHARED or greater lock on the file
    ** already.
    */
    int failed = 0;
    assert( 0!=pFile->locktype );
    if (locktype >= RESERVED_LOCK && pFile->locktype < RESERVED_LOCK) {
        /* Acquire a RESERVED lock */
        failed = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1);
      if( !failed ){
        context->reserved = 1;
      }
    }
    if (!failed && locktype == EXCLUSIVE_LOCK) {
      /* Acquire an EXCLUSIVE lock */
        
      /* Remove the shared lock before trying the range.  we'll need to 
      ** reestablish the shared lock if we can't get the  afpUnlock
      */
      if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST +
                         pLock->sharedByte, 1, 0)) ){
        int failed2 = SQLITE_OK;
        /* now attemmpt to get the exclusive lock range */
        failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST, 
                               SHARED_SIZE, 1);
        if( failed && (failed2 = afpSetLock(context->dbPath, pFile, 
                       SHARED_FIRST + pLock->sharedByte, 1, 1)) ){
          /* Can't reestablish the shared lock.  Sqlite can't deal, this is
          ** a critical I/O error
          */
          rc = ((failed & SQLITE_IOERR) == SQLITE_IOERR) ? failed2 : 
               SQLITE_IOERR_LOCK;
          goto afp_end_lock;
        } 
      }else{
        rc = failed; 
      }
    }
    if( failed ){
      rc = failed;
    }
  }
  
  if( rc==SQLITE_OK ){
    pFile->locktype = locktype;
    pLock->locktype = locktype;
  }else if( locktype==EXCLUSIVE_LOCK ){
    pFile->locktype = PENDING_LOCK;
    pLock->locktype = PENDING_LOCK;
  }
  
afp_end_lock:
  unixLeaveMutex();
  OSTRACE4("LOCK    %d %s %s (afp)\n", pFile->h, locktypeName(locktype), 
         rc==SQLITE_OK ? "ok" : "failed");
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int afpUnlock(sqlite3_file *id, int locktype) {
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  struct unixLockInfo *pLock;
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  int skipShared = 0;
#ifdef SQLITE_TEST
  int h = pFile->h;
#endif

  assert( pFile );
  OSTRACE7("UNLOCK  %d %d was %d(%d,%d) pid=%d (afp)\n", pFile->h, locktype,

           pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());

  assert( locktype<=SHARED_LOCK );
  if( pFile->locktype<=locktype ){
    return SQLITE_OK;
  }
  if( CHECK_THREADID(pFile) ){
    return SQLITE_MISUSE_BKPT;
  }
  unixEnterMutex();
  pLock = pFile->pLock;
  assert( pLock->cnt!=0 );
  if( pFile->locktype>SHARED_LOCK ){
    assert( pLock->locktype==pFile->locktype );
    SimulateIOErrorBenign(1);
    SimulateIOError( h=(-1) )
    SimulateIOErrorBenign(0);
    
#ifndef NDEBUG
    /* When reducing a lock such that other processes can start
    ** reading the database file again, make sure that the
    ** transaction counter was updated if any part of the database
    ** file changed.  If the transaction counter is not updated,
    ** other connections to the same file might not realize that
    ** the file has changed and hence might not know to flush their
    ** cache.  The use of a stale cache can lead to database corruption.
    */
    assert( pFile->inNormalWrite==0
           || pFile->dbUpdate==0
           || pFile->transCntrChng==1 );
    pFile->inNormalWrite = 0;
#endif
    
    if( pFile->locktype==EXCLUSIVE_LOCK ){
      rc = afpSetLock(context->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0);
      if( rc==SQLITE_OK && (locktype==SHARED_LOCK || pLock->cnt>1) ){
        /* only re-establish the shared lock if necessary */
        int sharedLockByte = SHARED_FIRST+pLock->sharedByte;
        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 1);
      } else {
        skipShared = 1;
      }
    }
    if( rc==SQLITE_OK && pFile->locktype>=PENDING_LOCK ){
      rc = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
    } 
    if( rc==SQLITE_OK && pFile->locktype>=RESERVED_LOCK && context->reserved ){
      rc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0);
      if( !rc ){ 
        context->reserved = 0; 
      }
    }
    if( rc==SQLITE_OK && (locktype==SHARED_LOCK || pLock->cnt>1)){
      pLock->locktype = SHARED_LOCK;
    }
  }
  if( rc==SQLITE_OK && locktype==NO_LOCK ){

    /* Decrement the shared lock counter.  Release the lock using an
    ** OS call only when all threads in this same process have released
    ** the lock.
    */
    unsigned long long sharedLockByte = SHARED_FIRST+pLock->sharedByte;
    pLock->cnt--;
    if( pLock->cnt==0 ){
      SimulateIOErrorBenign(1);
      SimulateIOError( h=(-1) )
      SimulateIOErrorBenign(0);
      if( !skipShared ){
        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 0);
      }
      if( !rc ){
        pLock->locktype = NO_LOCK;
        pFile->locktype = NO_LOCK;
      }
    }
    if( rc==SQLITE_OK ){
      struct unixOpenCnt *pOpen = pFile->pOpen;
        
      pOpen->nLock--;
      assert( pOpen->nLock>=0 );
      if( pOpen->nLock==0 ){
        rc = closePendingFds(pFile);
      }
    }
  }
  
  unixLeaveMutex();
  if( rc==SQLITE_OK ) pFile->locktype = locktype;
  return rc;
}

/*
** Close a file & cleanup AFP specific locking context 
*/
static int afpClose(sqlite3_file *id) {
  int rc = SQLITE_OK;
  if( id ){
    unixFile *pFile = (unixFile*)id;
    afpUnlock(id, NO_LOCK);
    unixEnterMutex();
    if( pFile->pOpen && pFile->pOpen->nLock ){
      /* If there are outstanding locks, do not actually close the file just
      ** yet because that would clear those locks.  Instead, add the file
      ** descriptor to pOpen->aPending.  It will be automatically closed when
      ** the last lock is cleared.
      */
      setPendingFd(pFile);
    }
    releaseLockInfo(pFile->pLock);
    releaseOpenCnt(pFile->pOpen);
    sqlite3_free(pFile->lockingContext);
    rc = closeUnixFile(id);
    unixLeaveMutex();
  }
  return rc;
}








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<







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2269








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2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437



2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
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2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505


2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536

2537
2538
2539
2540
2541
2542
2543
**    SHARED -> (PENDING) -> EXCLUSIVE
**    RESERVED -> (PENDING) -> EXCLUSIVE
**    PENDING -> EXCLUSIVE
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int afpLock(sqlite3_file *id, int eFileLock){
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  unixInodeInfo *pInode = pFile->pInode;
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  
  assert( pFile );
  OSTRACE(("LOCK    %d %s was %s(%s,%d) pid=%d (afp)\n", pFile->h,
           azFileLock(eFileLock), azFileLock(pFile->eFileLock),
           azFileLock(pInode->eFileLock), pInode->nShared , getpid()));

  /* If there is already a lock of this type or more restrictive on the
  ** unixFile, do nothing. Don't use the afp_end_lock: exit path, as
  ** unixEnterMutex() hasn't been called yet.
  */
  if( pFile->eFileLock>=eFileLock ){
    OSTRACE(("LOCK    %d %s ok (already held) (afp)\n", pFile->h,
           azFileLock(eFileLock)));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct
  **  (1) We never move from unlocked to anything higher than shared lock.
  **  (2) SQLite never explicitly requests a pendig lock.
  **  (3) A shared lock is always held when a reserve lock is requested.
  */
  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
  assert( eFileLock!=PENDING_LOCK );
  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );
  
  /* This mutex is needed because pFile->pInode is shared across threads
  */
  unixEnterMutex();








  pInode = pFile->pInode;

  /* If some thread using this PID has a lock via a different unixFile*
  ** handle that precludes the requested lock, return BUSY.
  */
  if( (pFile->eFileLock!=pInode->eFileLock && 
       (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK))
     ){
    rc = SQLITE_BUSY;
    goto afp_end_lock;
  }
  
  /* If a SHARED lock is requested, and some thread using this PID already
  ** has a SHARED or RESERVED lock, then increment reference counts and
  ** return SQLITE_OK.
  */
  if( eFileLock==SHARED_LOCK && 
     (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){
    assert( eFileLock==SHARED_LOCK );
    assert( pFile->eFileLock==0 );
    assert( pInode->nShared>0 );
    pFile->eFileLock = SHARED_LOCK;
    pInode->nShared++;
    pInode->nLock++;
    goto afp_end_lock;
  }
    
  /* A PENDING lock is needed before acquiring a SHARED lock and before
  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
  ** be released.
  */
  if( eFileLock==SHARED_LOCK 
      || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK)
  ){
    int failed;
    failed = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 1);
    if (failed) {
      rc = failed;
      goto afp_end_lock;
    }
  }
  
  /* If control gets to this point, then actually go ahead and make
  ** operating system calls for the specified lock.
  */
  if( eFileLock==SHARED_LOCK ){
    int lrc1, lrc2, lrc1Errno;
    long lk, mask;
    
    assert( pInode->nShared==0 );
    assert( pInode->eFileLock==0 );
        
    mask = (sizeof(long)==8) ? LARGEST_INT64 : 0x7fffffff;
    /* Now get the read-lock SHARED_LOCK */
    /* note that the quality of the randomness doesn't matter that much */
    lk = random(); 
    pInode->sharedByte = (lk & mask)%(SHARED_SIZE - 1);
    lrc1 = afpSetLock(context->dbPath, pFile, 
          SHARED_FIRST+pInode->sharedByte, 1, 1);
    if( IS_LOCK_ERROR(lrc1) ){
      lrc1Errno = pFile->lastErrno;
    }
    /* Drop the temporary PENDING lock */
    lrc2 = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
    
    if( IS_LOCK_ERROR(lrc1) ) {
      pFile->lastErrno = lrc1Errno;
      rc = lrc1;
      goto afp_end_lock;
    } else if( IS_LOCK_ERROR(lrc2) ){
      rc = lrc2;
      goto afp_end_lock;
    } else if( lrc1 != SQLITE_OK ) {
      rc = lrc1;
    } else {
      pFile->eFileLock = SHARED_LOCK;
      pInode->nLock++;
      pInode->nShared = 1;
    }
  }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){
    /* We are trying for an exclusive lock but another thread in this
     ** same process is still holding a shared lock. */
    rc = SQLITE_BUSY;
  }else{
    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
    ** assumed that there is a SHARED or greater lock on the file
    ** already.
    */
    int failed = 0;
    assert( 0!=pFile->eFileLock );
    if (eFileLock >= RESERVED_LOCK && pFile->eFileLock < RESERVED_LOCK) {
        /* Acquire a RESERVED lock */
        failed = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1);
      if( !failed ){
        context->reserved = 1;
      }
    }
    if (!failed && eFileLock == EXCLUSIVE_LOCK) {
      /* Acquire an EXCLUSIVE lock */
        
      /* Remove the shared lock before trying the range.  we'll need to 
      ** reestablish the shared lock if we can't get the  afpUnlock
      */
      if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST +
                         pInode->sharedByte, 1, 0)) ){
        int failed2 = SQLITE_OK;
        /* now attemmpt to get the exclusive lock range */
        failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST, 
                               SHARED_SIZE, 1);
        if( failed && (failed2 = afpSetLock(context->dbPath, pFile, 
                       SHARED_FIRST + pInode->sharedByte, 1, 1)) ){
          /* Can't reestablish the shared lock.  Sqlite can't deal, this is
          ** a critical I/O error
          */
          rc = ((failed & SQLITE_IOERR) == SQLITE_IOERR) ? failed2 : 
               SQLITE_IOERR_LOCK;
          goto afp_end_lock;
        } 
      }else{
        rc = failed; 
      }
    }
    if( failed ){
      rc = failed;
    }
  }
  
  if( rc==SQLITE_OK ){
    pFile->eFileLock = eFileLock;
    pInode->eFileLock = eFileLock;
  }else if( eFileLock==EXCLUSIVE_LOCK ){
    pFile->eFileLock = PENDING_LOCK;
    pInode->eFileLock = PENDING_LOCK;
  }
  
afp_end_lock:
  unixLeaveMutex();
  OSTRACE(("LOCK    %d %s %s (afp)\n", pFile->h, azFileLock(eFileLock), 
         rc==SQLITE_OK ? "ok" : "failed"));
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int afpUnlock(sqlite3_file *id, int eFileLock) {
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  unixInodeInfo *pInode;
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  int skipShared = 0;
#ifdef SQLITE_TEST
  int h = pFile->h;
#endif

  assert( pFile );
  OSTRACE(("UNLOCK  %d %d was %d(%d,%d) pid=%d (afp)\n", pFile->h, eFileLock,
           pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared,
           getpid()));

  assert( eFileLock<=SHARED_LOCK );
  if( pFile->eFileLock<=eFileLock ){
    return SQLITE_OK;
  }



  unixEnterMutex();
  pInode = pFile->pInode;
  assert( pInode->nShared!=0 );
  if( pFile->eFileLock>SHARED_LOCK ){
    assert( pInode->eFileLock==pFile->eFileLock );
    SimulateIOErrorBenign(1);
    SimulateIOError( h=(-1) )
    SimulateIOErrorBenign(0);
    
#ifndef NDEBUG
    /* When reducing a lock such that other processes can start
    ** reading the database file again, make sure that the
    ** transaction counter was updated if any part of the database
    ** file changed.  If the transaction counter is not updated,
    ** other connections to the same file might not realize that
    ** the file has changed and hence might not know to flush their
    ** cache.  The use of a stale cache can lead to database corruption.
    */
    assert( pFile->inNormalWrite==0
           || pFile->dbUpdate==0
           || pFile->transCntrChng==1 );
    pFile->inNormalWrite = 0;
#endif
    
    if( pFile->eFileLock==EXCLUSIVE_LOCK ){
      rc = afpSetLock(context->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0);
      if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1) ){
        /* only re-establish the shared lock if necessary */
        int sharedLockByte = SHARED_FIRST+pInode->sharedByte;
        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 1);
      } else {
        skipShared = 1;
      }
    }
    if( rc==SQLITE_OK && pFile->eFileLock>=PENDING_LOCK ){
      rc = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
    } 
    if( rc==SQLITE_OK && pFile->eFileLock>=RESERVED_LOCK && context->reserved ){
      rc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0);
      if( !rc ){ 
        context->reserved = 0; 
      }
    }
    if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1)){
      pInode->eFileLock = SHARED_LOCK;
    }
  }
  if( rc==SQLITE_OK && eFileLock==NO_LOCK ){

    /* Decrement the shared lock counter.  Release the lock using an
    ** OS call only when all threads in this same process have released
    ** the lock.
    */
    unsigned long long sharedLockByte = SHARED_FIRST+pInode->sharedByte;
    pInode->nShared--;
    if( pInode->nShared==0 ){
      SimulateIOErrorBenign(1);
      SimulateIOError( h=(-1) )
      SimulateIOErrorBenign(0);
      if( !skipShared ){
        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 0);
      }
      if( !rc ){
        pInode->eFileLock = NO_LOCK;
        pFile->eFileLock = NO_LOCK;
      }
    }
    if( rc==SQLITE_OK ){


      pInode->nLock--;
      assert( pInode->nLock>=0 );
      if( pInode->nLock==0 ){
        rc = closePendingFds(pFile);
      }
    }
  }
  
  unixLeaveMutex();
  if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock;
  return rc;
}

/*
** Close a file & cleanup AFP specific locking context 
*/
static int afpClose(sqlite3_file *id) {
  int rc = SQLITE_OK;
  if( id ){
    unixFile *pFile = (unixFile*)id;
    afpUnlock(id, NO_LOCK);
    unixEnterMutex();
    if( pFile->pInode && pFile->pInode->nLock ){
      /* If there are outstanding locks, do not actually close the file just
      ** yet because that would clear those locks.  Instead, add the file
      ** descriptor to pInode->aPending.  It will be automatically closed when
      ** the last lock is cleared.
      */
      setPendingFd(pFile);
    }
    releaseLockInfo(pFile->pInode);

    sqlite3_free(pFile->lockingContext);
    rc = closeUnixFile(id);
    unixLeaveMutex();
  }
  return rc;
}

2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
******************************************************************************/

/******************************************************************************
*************************** Begin NFS Locking ********************************/

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
/*
 ** Lower the locking level on file descriptor pFile to locktype.  locktype
 ** must be either NO_LOCK or SHARED_LOCK.
 **
 ** If the locking level of the file descriptor is already at or below
 ** the requested locking level, this routine is a no-op.
 */
static int nfsUnlock(sqlite3_file *id, int locktype){
  return _posixUnlock(id, locktype, 1);
}

#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
/*
** The code above is the NFS lock implementation.  The code is specific
** to MacOSX and does not work on other unix platforms.  No alternative
** is available.  







|





|
|







2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
******************************************************************************/

/******************************************************************************
*************************** Begin NFS Locking ********************************/

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
/*
 ** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
 ** must be either NO_LOCK or SHARED_LOCK.
 **
 ** If the locking level of the file descriptor is already at or below
 ** the requested locking level, this routine is a no-op.
 */
static int nfsUnlock(sqlite3_file *id, int eFileLock){
  return _posixUnlock(id, eFileLock, 1);
}

#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
/*
** The code above is the NFS lock implementation.  The code is specific
** to MacOSX and does not work on other unix platforms.  No alternative
** is available.  
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
  }
  got = read(id->h, pBuf, cnt);
#endif
  TIMER_END;
  if( got<0 ){
    ((unixFile*)id)->lastErrno = errno;
  }
  OSTRACE5("READ    %-3d %5d %7lld %llu\n", id->h, got, offset, TIMER_ELAPSED);
  return got;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.







|







2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
  }
  got = read(id->h, pBuf, cnt);
#endif
  TIMER_END;
  if( got<0 ){
    ((unixFile*)id)->lastErrno = errno;
  }
  OSTRACE(("READ    %-3d %5d %7lld %llu\n", id->h, got, offset, TIMER_ELAPSED));
  return got;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
  got = write(id->h, pBuf, cnt);
#endif
  TIMER_END;
  if( got<0 ){
    ((unixFile*)id)->lastErrno = errno;
  }

  OSTRACE5("WRITE   %-3d %5d %7lld %llu\n", id->h, got, offset, TIMER_ELAPSED);
  return got;
}


/*
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.







|







2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
  got = write(id->h, pBuf, cnt);
#endif
  TIMER_END;
  if( got<0 ){
    ((unixFile*)id)->lastErrno = errno;
  }

  OSTRACE(("WRITE   %-3d %5d %7lld %llu\n", id->h, got, offset, TIMER_ELAPSED));
  return got;
}


/*
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260

  /* Unix cannot, but some systems may return SQLITE_FULL from here. This
  ** line is to test that doing so does not cause any problems.
  */
  SimulateDiskfullError( return SQLITE_FULL );

  assert( pFile );
  OSTRACE2("SYNC    %-3d\n", pFile->h);
  rc = full_fsync(pFile->h, isFullsync, isDataOnly);
  SimulateIOError( rc=1 );
  if( rc ){
    pFile->lastErrno = errno;
    return SQLITE_IOERR_FSYNC;
  }
  if( pFile->dirfd>=0 ){
    int err;
    OSTRACE4("DIRSYNC %-3d (have_fullfsync=%d fullsync=%d)\n", pFile->dirfd,
            HAVE_FULLFSYNC, isFullsync);
#ifndef SQLITE_DISABLE_DIRSYNC
    /* The directory sync is only attempted if full_fsync is
    ** turned off or unavailable.  If a full_fsync occurred above,
    ** then the directory sync is superfluous.
    */
    if( (!HAVE_FULLFSYNC || !isFullsync) && full_fsync(pFile->dirfd,0,0) ){
       /*







|








|
|







2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949

  /* Unix cannot, but some systems may return SQLITE_FULL from here. This
  ** line is to test that doing so does not cause any problems.
  */
  SimulateDiskfullError( return SQLITE_FULL );

  assert( pFile );
  OSTRACE(("SYNC    %-3d\n", pFile->h));
  rc = full_fsync(pFile->h, isFullsync, isDataOnly);
  SimulateIOError( rc=1 );
  if( rc ){
    pFile->lastErrno = errno;
    return SQLITE_IOERR_FSYNC;
  }
  if( pFile->dirfd>=0 ){
    int err;
    OSTRACE(("DIRSYNC %-3d (have_fullfsync=%d fullsync=%d)\n", pFile->dirfd,
            HAVE_FULLFSYNC, isFullsync));
#ifndef SQLITE_DISABLE_DIRSYNC
    /* The directory sync is only attempted if full_fsync is
    ** turned off or unavailable.  If a full_fsync occurred above,
    ** then the directory sync is superfluous.
    */
    if( (!HAVE_FULLFSYNC || !isFullsync) && full_fsync(pFile->dirfd,0,0) ){
       /*
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
  SimulateIOError( rc=1 );
  if( rc!=0 ){
    ((unixFile*)id)->lastErrno = errno;
    return SQLITE_IOERR_FSTAT;
  }
  *pSize = buf.st_size;

  /* When opening a zero-size database, the findLockInfo() procedure
  ** writes a single byte into that file in order to work around a bug
  ** in the OS-X msdos filesystem.  In order to avoid problems with upper
  ** layers, we need to report this file size as zero even though it is
  ** really 1.   Ticket #3260.
  */
  if( *pSize==1 ) *pSize = 0;








|







3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
  SimulateIOError( rc=1 );
  if( rc!=0 ){
    ((unixFile*)id)->lastErrno = errno;
    return SQLITE_IOERR_FSTAT;
  }
  *pSize = buf.st_size;

  /* When opening a zero-size database, the findInodeInfo() procedure
  ** writes a single byte into that file in order to work around a bug
  ** in the OS-X msdos filesystem.  In order to avoid problems with upper
  ** layers, we need to report this file size as zero even though it is
  ** really 1.   Ticket #3260.
  */
  if( *pSize==1 ) *pSize = 0;

3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359

/*
** Information and control of an open file handle.
*/
static int unixFileControl(sqlite3_file *id, int op, void *pArg){
  switch( op ){
    case SQLITE_FCNTL_LOCKSTATE: {
      *(int*)pArg = ((unixFile*)id)->locktype;
      return SQLITE_OK;
    }
    case SQLITE_LAST_ERRNO: {
      *(int*)pArg = ((unixFile*)id)->lastErrno;
      return SQLITE_OK;
    }
#ifndef NDEBUG







|







3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048

/*
** Information and control of an open file handle.
*/
static int unixFileControl(sqlite3_file *id, int op, void *pArg){
  switch( op ){
    case SQLITE_FCNTL_LOCKSTATE: {
      *(int*)pArg = ((unixFile*)id)->eFileLock;
      return SQLITE_OK;
    }
    case SQLITE_LAST_ERRNO: {
      *(int*)pArg = ((unixFile*)id)->lastErrno;
      return SQLITE_OK;
    }
#ifndef NDEBUG
3396
3397
3398
3399
3400
3401
3402





























































































































































































































































































































































































































































































































































































































































































































































































































3403
3404
3405
3406
3407
3408
3409
** Return the device characteristics for the file. This is always 0 for unix.
*/
static int unixDeviceCharacteristics(sqlite3_file *NotUsed){
  UNUSED_PARAMETER(NotUsed);
  return 0;
}






























































































































































































































































































































































































































































































































































































































































































































































































































/*
** Here ends the implementation of all sqlite3_file methods.
**
********************** End sqlite3_file Methods *******************************
******************************************************************************/

/*







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** Return the device characteristics for the file. This is always 0 for unix.
*/
static int unixDeviceCharacteristics(sqlite3_file *NotUsed){
  UNUSED_PARAMETER(NotUsed);
  return 0;
}

#ifndef SQLITE_OMIT_WAL


/*
** Object used to represent an shared memory buffer.  
**
** When multiple threads all reference the same wal-index, each thread
** has its own unixShm object, but they all point to a single instance
** of this unixShmNode object.  In other words, each wal-index is opened
** only once per process.
**
** Each unixShmNode object is connected to a single unixInodeInfo object.
** We could coalesce this object into unixInodeInfo, but that would mean
** every open file that does not use shared memory (in other words, most
** open files) would have to carry around this extra information.  So
** the unixInodeInfo object contains a pointer to this unixShmNode object
** and the unixShmNode object is created only when needed.
**
** unixMutexHeld() must be true when creating or destroying
** this object or while reading or writing the following fields:
**
**      nRef
**
** The following fields are read-only after the object is created:
** 
**      fid
**      zFilename
**
** Either unixShmNode.mutex must be held or unixShmNode.nRef==0 and
** unixMutexHeld() is true when reading or writing any other field
** in this structure.
**
** To avoid deadlocks, mutex and mutexBuf are always released in the
** reverse order that they are acquired.  mutexBuf is always acquired
** first and released last.  This invariant is check by asserting
** sqlite3_mutex_notheld() on mutex whenever mutexBuf is acquired or
** released.
*/
struct unixShmNode {
  unixInodeInfo *pInode;     /* unixInodeInfo that owns this SHM node */
  sqlite3_mutex *mutex;      /* Mutex to access this object */
  sqlite3_mutex *mutexBuf;   /* Mutex to access zBuf[] */
  char *zFilename;           /* Name of the mmapped file */
  int h;                     /* Open file descriptor */
  int szMap;                 /* Size of the mapping into memory */
  char *pMMapBuf;            /* Where currently mmapped().  NULL if unmapped */
  int nRef;                  /* Number of unixShm objects pointing to this */
  unixShm *pFirst;           /* All unixShm objects pointing to this */
#ifdef SQLITE_DEBUG
  u8 exclMask;               /* Mask of exclusive locks held */
  u8 sharedMask;             /* Mask of shared locks held */
  u8 nextShmId;              /* Next available unixShm.id value */
#endif
};

/*
** Structure used internally by this VFS to record the state of an
** open shared memory connection.
**
** The following fields are initialized when this object is created and
** are read-only thereafter:
**
**    unixShm.pFile
**    unixShm.id
**
** All other fields are read/write.  The unixShm.pFile->mutex must be held
** while accessing any read/write fields.
*/
struct unixShm {
  unixShmNode *pShmNode;     /* The underlying unixShmNode object */
  unixShm *pNext;            /* Next unixShm with the same unixShmNode */
  u8 lockState;              /* Current lock state */
  u8 hasMutex;               /* True if holding the unixShmNode mutex */
  u8 hasMutexBuf;            /* True if holding pFile->mutexBuf */
  u8 sharedMask;             /* Mask of shared locks held */
  u8 exclMask;               /* Mask of exclusive locks held */
#ifdef SQLITE_DEBUG
  u8 id;                     /* Id of this connection within its unixShmNode */
#endif
};

/*
** Size increment by which shared memory grows
*/
#define SQLITE_UNIX_SHM_INCR  4096

/*
** Constants used for locking
*/
#define UNIX_SHM_BASE      32        /* Byte offset of the first lock byte */
#define UNIX_SHM_DMS       0x01      /* Mask for Dead-Man-Switch lock */
#define UNIX_SHM_A         0x10      /* Mask for region locks... */
#define UNIX_SHM_B         0x20
#define UNIX_SHM_C         0x40
#define UNIX_SHM_D         0x80

#ifdef SQLITE_DEBUG
/*
** Return a pointer to a nul-terminated string in static memory that
** describes a locking mask.  The string is of the form "MSABCD" with
** each character representing a lock.  "M" for MUTEX, "S" for DMS, 
** and "A" through "D" for the region locks.  If a lock is held, the
** letter is shown.  If the lock is not held, the letter is converted
** to ".".
**
** This routine is for debugging purposes only and does not appear
** in a production build.
*/
static const char *unixShmLockString(u8 mask){
  static char zBuf[48];
  static int iBuf = 0;
  char *z;

  z = &zBuf[iBuf];
  iBuf += 8;
  if( iBuf>=sizeof(zBuf) ) iBuf = 0;

  z[0] = (mask & UNIX_SHM_DMS)   ? 'S' : '.';
  z[1] = (mask & UNIX_SHM_A)     ? 'A' : '.';
  z[2] = (mask & UNIX_SHM_B)     ? 'B' : '.';
  z[3] = (mask & UNIX_SHM_C)     ? 'C' : '.';
  z[4] = (mask & UNIX_SHM_D)     ? 'D' : '.';
  z[5] = 0;
  return z;
}
#endif /* SQLITE_DEBUG */

/*
** Apply posix advisory locks for all bytes identified in lockMask.
**
** lockMask might contain multiple bits but all bits are guaranteed
** to be contiguous.
**
** Locks block if the mask is exactly UNIX_SHM_C and are non-blocking
** otherwise.
*/
static int unixShmSystemLock(
  unixShmNode *pShmNode, /* Apply locks to this open shared-memory segment */
  int lockType,          /* F_UNLCK, F_RDLCK, or F_WRLCK */
  u8 lockMask            /* Which bytes to lock or unlock */
){
  struct flock f;       /* The posix advisory locking structure */
  int lockOp;           /* The opcode for fcntl() */
  int i;                /* Offset into the locking byte range */
  int rc;               /* Result code form fcntl() */
  u8 mask;              /* Mask of bits in lockMask */

  /* Access to the unixShmNode object is serialized by the caller */
  assert( sqlite3_mutex_held(pShmNode->mutex) || pShmNode->nRef==0 );

  /* Initialize the locking parameters */
  memset(&f, 0, sizeof(f));
  f.l_type = lockType;
  f.l_whence = SEEK_SET;
  if( lockMask==UNIX_SHM_C && lockType!=F_UNLCK ){
    lockOp = F_SETLKW;
    OSTRACE(("SHM-LOCK requesting blocking lock\n"));
  }else{
    lockOp = F_SETLK;
  }

  /* Find the first bit in lockMask that is set */
  for(i=0, mask=0x01; mask!=0 && (lockMask&mask)==0; mask <<= 1, i++){}
  assert( mask!=0 );
  f.l_start = i+UNIX_SHM_BASE;
  f.l_len = 1;

  /* Extend the locking range for each additional bit that is set */
  mask <<= 1;
  while( mask!=0 && (lockMask & mask)!=0 ){
    f.l_len++;
    mask <<= 1;
  }

  /* Verify that all bits set in lockMask are contiguous */
  assert( mask==0 || (lockMask & ~(mask | (mask-1)))==0 );

  /* Acquire the system-level lock */
  rc = fcntl(pShmNode->h, lockOp, &f);
  rc = (rc!=(-1)) ? SQLITE_OK : SQLITE_BUSY;

  /* Update the global lock state and do debug tracing */
#ifdef SQLITE_DEBUG
  OSTRACE(("SHM-LOCK "));
  if( rc==SQLITE_OK ){
    if( lockType==F_UNLCK ){
      OSTRACE(("unlock ok"));
      pShmNode->exclMask &= ~lockMask;
      pShmNode->sharedMask &= ~lockMask;
    }else if( lockType==F_RDLCK ){
      OSTRACE(("read-lock ok"));
      pShmNode->exclMask &= ~lockMask;
      pShmNode->sharedMask |= lockMask;
    }else{
      assert( lockType==F_WRLCK );
      OSTRACE(("write-lock ok"));
      pShmNode->exclMask |= lockMask;
      pShmNode->sharedMask &= ~lockMask;
    }
  }else{
    if( lockType==F_UNLCK ){
      OSTRACE(("unlock failed"));
    }else if( lockType==F_RDLCK ){
      OSTRACE(("read-lock failed"));
    }else{
      assert( lockType==F_WRLCK );
      OSTRACE(("write-lock failed"));
    }
  }
  OSTRACE((" - change requested %s - afterwards %s:%s\n",
           unixShmLockString(lockMask),
           unixShmLockString(pShmNode->sharedMask),
           unixShmLockString(pShmNode->exclMask)));
#endif

  return rc;        
}

/*
** For connection p, unlock all of the locks identified by the unlockMask
** parameter.
*/
static int unixShmUnlock(
  unixShmNode *pShmNode,   /* The underlying shared-memory file */
  unixShm *p,              /* The connection to be unlocked */
  u8 unlockMask            /* Mask of locks to be unlocked */
){
  int rc;      /* Result code */
  unixShm *pX; /* For looping over all sibling connections */
  u8 allMask;  /* Union of locks held by connections other than "p" */

  /* Access to the unixShmNode object is serialized by the caller */
  assert( sqlite3_mutex_held(pShmNode->mutex) );

  /* Compute locks held by sibling connections */
  allMask = 0;
  for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
    allMask |= pX->sharedMask;
  }

  /* Unlock the system-level locks */
  if( (unlockMask & allMask)!=unlockMask ){
    rc = unixShmSystemLock(pShmNode, F_UNLCK, unlockMask & ~allMask);
  }else{
    rc = SQLITE_OK;
  }

  /* Undo the local locks */
  if( rc==SQLITE_OK ){
    p->exclMask &= ~unlockMask;
    p->sharedMask &= ~unlockMask;
  } 
  return rc;
}

/*
** Get reader locks for connection p on all locks in the readMask parameter.
*/
static int unixShmSharedLock(
  unixShmNode *pShmNode,   /* The underlying shared-memory file */
  unixShm *p,              /* The connection to get the shared locks */
  u8 readMask              /* Mask of shared locks to be acquired */
){
  int rc;        /* Result code */
  unixShm *pX;   /* For looping over all sibling connections */
  u8 allShared;  /* Union of locks held by connections other than "p" */

  /* Access to the unixShmNode object is serialized by the caller */
  assert( sqlite3_mutex_held(pShmNode->mutex) );

  /* Find out which shared locks are already held by sibling connections.
  ** If any sibling already holds an exclusive lock, go ahead and return
  ** SQLITE_BUSY.
  */
  allShared = 0;
  for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    if( (pX->exclMask & readMask)!=0 ) return SQLITE_BUSY;
    allShared |= pX->sharedMask;
  }

  /* Get shared locks at the system level, if necessary */
  if( (~allShared) & readMask ){
    rc = unixShmSystemLock(pShmNode, F_RDLCK, readMask);
  }else{
    rc = SQLITE_OK;
  }

  /* Get the local shared locks */
  if( rc==SQLITE_OK ){
    p->sharedMask |= readMask;
  }
  return rc;
}

/*
** For connection p, get an exclusive lock on all locks identified in
** the writeMask parameter.
*/
static int unixShmExclusiveLock(
  unixShmNode *pShmNode,    /* The underlying shared-memory file */
  unixShm *p,               /* The connection to get the exclusive locks */
  u8 writeMask              /* Mask of exclusive locks to be acquired */
){
  int rc;        /* Result code */
  unixShm *pX;   /* For looping over all sibling connections */

  /* Access to the unixShmNode object is serialized by the caller */
  assert( sqlite3_mutex_held(pShmNode->mutex) );

  /* Make sure no sibling connections hold locks that will block this
  ** lock.  If any do, return SQLITE_BUSY right away.
  */
  for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    if( (pX->exclMask & writeMask)!=0 ) return SQLITE_BUSY;
    if( (pX->sharedMask & writeMask)!=0 ) return SQLITE_BUSY;
  }

  /* Get the exclusive locks at the system level.  Then if successful
  ** also mark the local connection as being locked.
  */
  rc = unixShmSystemLock(pShmNode, F_WRLCK, writeMask);
  if( rc==SQLITE_OK ){
    p->sharedMask &= ~writeMask;
    p->exclMask |= writeMask;
  }
  return rc;
}

/*
** Purge the unixShmNodeList list of all entries with unixShmNode.nRef==0.
**
** This is not a VFS shared-memory method; it is a utility function called
** by VFS shared-memory methods.
*/
static void unixShmPurge(unixFile *pFd){
  unixShmNode *p = pFd->pInode->pShmNode;
  assert( unixMutexHeld() );
  if( p && p->nRef==0 ){
    assert( p->pInode==pFd->pInode );
    if( p->mutex ) sqlite3_mutex_free(p->mutex);
    if( p->mutexBuf ) sqlite3_mutex_free(p->mutexBuf);
    if( p->h>=0 ) close(p->h);
    p->pInode->pShmNode = 0;
    sqlite3_free(p);
  }
}

/*
** Open a shared-memory area.  This particular implementation uses
** mmapped files.
**
** zName is a filename used to identify the shared-memory area.  The
** implementation does not (and perhaps should not) use this name
** directly, but rather use it as a template for finding an appropriate
** name for the shared-memory storage.  In this implementation, the
** string "-index" is appended to zName and used as the name of the
** mmapped file.
**
** When opening a new shared-memory file, if no other instances of that
** file are currently open, in this process or in other processes, then
** the file must be truncated to zero length or have its header cleared.
*/
static int unixShmOpen(
  sqlite3_file *fd      /* The file descriptor of the associated database */
){
  struct unixShm *p = 0;             /* The connection to be opened */
  struct unixShmNode *pShmNode = 0;  /* The underlying mmapped file */
  int rc;                            /* Result code */
  struct unixFile *pDbFd;            /* Underlying database file */
  int nPath;                         /* Size of pDbFd->zPath in bytes */

  /* Allocate space for the new sqlite3_shm object.
  */
  p = sqlite3_malloc( sizeof(*p) );
  if( p==0 ) return SQLITE_NOMEM;
  memset(p, 0, sizeof(*p));
  pDbFd = (struct unixFile*)fd;
  assert( pDbFd->pShm==0 );

  /* Check to see if a unixShmNode object already exists.  Reuse an existing
  ** one if present.  Create a new one if necessary.
  */
  unixEnterMutex();
  pShmNode = pDbFd->pInode->pShmNode;
  if( pShmNode==0 ){
    nPath = strlen(pDbFd->zPath);
    pShmNode = sqlite3_malloc( sizeof(*pShmNode) + nPath + 15 );
    if( pShmNode==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    memset(pShmNode, 0, sizeof(*pShmNode));
    pShmNode->zFilename = (char*)&pShmNode[1];
    sqlite3_snprintf(nPath+15, pShmNode->zFilename,
                     "%s-wal-index", pDbFd->zPath);
    pShmNode->h = -1;
    pDbFd->pInode->pShmNode = pShmNode;
    pShmNode->pInode = pDbFd->pInode;
    pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pShmNode->mutex==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    pShmNode->mutexBuf = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pShmNode->mutexBuf==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }

    pShmNode->h = open(pShmNode->zFilename, O_RDWR|O_CREAT, 0664);
    if( pShmNode->h<0 ){
      rc = SQLITE_CANTOPEN_BKPT;
      goto shm_open_err;
    }

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    rc = SQLITE_OK;
    if( unixShmSystemLock(pShmNode, F_WRLCK, UNIX_SHM_DMS)==SQLITE_OK ){
      if( ftruncate(pShmNode->h, 0) ){
        rc = SQLITE_IOERR;
      }
    }
    if( rc==SQLITE_OK ){
      rc = unixShmSystemLock(pShmNode, F_RDLCK, UNIX_SHM_DMS);
    }
    if( rc ) goto shm_open_err;
  }

  /* Make the new connection a child of the unixShmNode */
  p->pShmNode = pShmNode;
  p->pNext = pShmNode->pFirst;
#ifdef SQLITE_DEBUG
  p->id = pShmNode->nextShmId++;
#endif
  pShmNode->pFirst = p;
  pShmNode->nRef++;
  pDbFd->pShm = p;
  unixLeaveMutex();
  return SQLITE_OK;

  /* Jump here on any error */
shm_open_err:
  unixShmPurge(pDbFd);       /* This call frees pShmNode if required */
  sqlite3_free(p);
  unixLeaveMutex();
  return rc;
}

/*
** Close a connection to shared-memory.  Delete the underlying 
** storage if deleteFlag is true.
*/
static int unixShmClose(
  sqlite3_file *fd,          /* The underlying database file */
  int deleteFlag             /* Delete shared-memory if true */
){
  unixShm *p;            /* The connection to be closed */
  unixShmNode *pShmNode; /* The underlying shared-memory file */
  unixShm **pp;          /* For looping over sibling connections */
  unixFile *pDbFd;       /* The underlying database file */

  pDbFd = (unixFile*)fd;
  p = pDbFd->pShm;
  if( p==0 ) return SQLITE_OK;
  pShmNode = p->pShmNode;

  assert( pShmNode==pDbFd->pInode->pShmNode );
  assert( pShmNode->pInode==pDbFd->pInode );

  /* Verify that the connection being closed holds no locks */
  assert( p->exclMask==0 );
  assert( p->sharedMask==0 );

  /* Remove connection p from the set of connections associated
  ** with pShmNode */
  sqlite3_mutex_enter(pShmNode->mutex);
  for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
  *pp = p->pNext;

  /* Free the connection p */
  sqlite3_free(p);
  pDbFd->pShm = 0;
  sqlite3_mutex_leave(pShmNode->mutex);

  /* If pShmNode->nRef has reached 0, then close the underlying
  ** shared-memory file, too */
  unixEnterMutex();
  assert( pShmNode->nRef>0 );
  pShmNode->nRef--;
  if( pShmNode->nRef==0 ){
    if( deleteFlag ) unlink(pShmNode->zFilename);
    unixShmPurge(pDbFd);
  }
  unixLeaveMutex();

  return SQLITE_OK;
}

/*
** Query and/or changes the size of the underlying storage for
** a shared-memory segment.  The reqSize parameter is the new size
** of the underlying storage, or -1 to do just a query.  The size
** of the underlying storage (after resizing if resizing occurs) is
** written into pNewSize.
**
** This routine does not (necessarily) change the size of the mapping 
** of the underlying storage into memory.  Use xShmGet() to change
** the mapping size.
**
** The reqSize parameter is the minimum size requested.  The implementation
** is free to expand the storage to some larger amount if it chooses.
*/
static int unixShmSize(
  sqlite3_file *fd,         /* The open database file holding SHM */
  int reqSize,              /* Requested size.  -1 for query only */
  int *pNewSize             /* Write new size here */
){
  unixFile *pDbFd = (unixFile*)fd;
  unixShm *p = pDbFd->pShm;
  unixShmNode *pShmNode = p->pShmNode;
  int rc = SQLITE_OK;
  struct stat sStat;

  assert( pShmNode==pDbFd->pInode->pShmNode );
  assert( pShmNode->pInode==pDbFd->pInode );

  /* On a query, this loop runs once.  When reqSize>=0, the loop potentially
  ** runs twice, except if the actual size is already greater than or equal
  ** to the requested size, reqSize is set to -1 on the first iteration and
  ** the loop only runs once.
  */
  while( 1 ){
    if( fstat(pShmNode->h, &sStat)==0 ){
      *pNewSize = (int)sStat.st_size;
      if( reqSize>=0 && reqSize<=(int)sStat.st_size ) break;
    }else{
      *pNewSize = 0;
      rc = SQLITE_IOERR;
      break;
    }
    if( reqSize<0 ) break;
    reqSize = (reqSize + SQLITE_UNIX_SHM_INCR - 1)/SQLITE_UNIX_SHM_INCR;
    reqSize *= SQLITE_UNIX_SHM_INCR;
    rc = ftruncate(pShmNode->h, reqSize);
    reqSize = -1;
  }
  return rc;
}


/*
** Map the shared storage into memory.  The minimum size of the
** mapping should be reqMapSize if reqMapSize is positive.  If
** reqMapSize is zero or negative, the implementation can choose
** whatever mapping size is convenient.
**
** *ppBuf is made to point to the memory which is a mapping of the
** underlying storage.  A mutex is acquired to prevent other threads
** from running while *ppBuf is in use in order to prevent other threads
** remapping *ppBuf out from under this thread.  The unixShmRelease()
** call will release the mutex.  However, if the lock state is CHECKPOINT,
** the mutex is not acquired because CHECKPOINT will never remap the
** buffer.  RECOVER might remap, though, so CHECKPOINT will acquire
** the mutex if and when it promotes to RECOVER.
**
** RECOVER needs to be atomic.  The same mutex that prevents *ppBuf from
** being remapped also prevents more than one thread from being in
** RECOVER at a time.  But, RECOVER sometimes wants to remap itself.
** To prevent RECOVER from losing its lock while remapping, the
** mutex is not released by unixShmRelease() when in RECOVER.
**
** *pNewMapSize is set to the size of the mapping.
**
** *ppBuf and *pNewMapSize might be NULL and zero if no space has
** yet been allocated to the underlying storage.
*/
static int unixShmGet(
  sqlite3_file *fd,        /* Database file holding shared memory */
  int reqMapSize,          /* Requested size of mapping. -1 means don't care */
  int *pNewMapSize,        /* Write new size of mapping here */
  void **ppBuf             /* Write mapping buffer origin here */
){
  unixFile *pDbFd = (unixFile*)fd;
  unixShm *p = pDbFd->pShm;
  unixShmNode *pShmNode = p->pShmNode;
  int rc = SQLITE_OK;

  assert( pShmNode==pDbFd->pInode->pShmNode );
  assert( pShmNode->pInode==pDbFd->pInode );

  if( p->lockState!=SQLITE_SHM_CHECKPOINT && p->hasMutexBuf==0 ){
    assert( sqlite3_mutex_notheld(pShmNode->mutex) );
    sqlite3_mutex_enter(pShmNode->mutexBuf);
    p->hasMutexBuf = 1;
  }
  sqlite3_mutex_enter(pShmNode->mutex);
  if( pShmNode->szMap==0 || reqMapSize>pShmNode->szMap ){
    int actualSize;
    if( unixShmSize(fd, -1, &actualSize)==SQLITE_OK
     && reqMapSize<actualSize
    ){
      reqMapSize = actualSize;
    }
    if( pShmNode->pMMapBuf ){
      munmap(pShmNode->pMMapBuf, pShmNode->szMap);
    }
    pShmNode->pMMapBuf = mmap(0, reqMapSize, PROT_READ|PROT_WRITE, MAP_SHARED,
                           pShmNode->h, 0);
    pShmNode->szMap = pShmNode->pMMapBuf ? reqMapSize : 0;
  }
  *pNewMapSize = pShmNode->szMap;
  *ppBuf = pShmNode->pMMapBuf;
  sqlite3_mutex_leave(pShmNode->mutex);
  return rc;
}

/*
** Release the lock held on the shared memory segment to that other
** threads are free to resize it if necessary.
**
** If the lock is not currently held, this routine is a harmless no-op.
**
** If the shared-memory object is in lock state RECOVER, then we do not
** really want to release the lock, so in that case too, this routine
** is a no-op.
*/
static int unixShmRelease(sqlite3_file *fd){
  unixFile *pDbFd = (unixFile*)fd;
  unixShm *p = pDbFd->pShm;

  if( p->hasMutexBuf && p->lockState!=SQLITE_SHM_RECOVER ){
    assert( sqlite3_mutex_notheld(p->pShmNode->mutex) );
    sqlite3_mutex_leave(p->pShmNode->mutexBuf);
    p->hasMutexBuf = 0;
  }
  return SQLITE_OK;
}

/*
** Symbolic names for LOCK states used for debugging.
*/
#ifdef SQLITE_DEBUG
static const char *azLkName[] = {
  "UNLOCK",
  "READ",
  "READ_FULL",
  "WRITE",
  "PENDING",
  "CHECKPOINT",
  "RECOVER"
};
#endif


/*
** Change the lock state for a shared-memory segment.
*/
static int unixShmLock(
  sqlite3_file *fd,          /* Database file holding the shared memory */
  int desiredLock,           /* One of SQLITE_SHM_xxxxx locking states */
  int *pGotLock              /* The lock you actually got */
){
  unixFile *pDbFd = (unixFile*)fd;
  unixShm *p = pDbFd->pShm;
  unixShmNode *pShmNode = p->pShmNode;
  int rc = SQLITE_PROTOCOL;

  assert( pShmNode==pDbFd->pInode->pShmNode );
  assert( pShmNode->pInode==pDbFd->pInode );

  /* Note that SQLITE_SHM_READ_FULL and SQLITE_SHM_PENDING are never
  ** directly requested; they are side effects from requesting
  ** SQLITE_SHM_READ and SQLITE_SHM_CHECKPOINT, respectively.
  */
  assert( desiredLock==SQLITE_SHM_UNLOCK
       || desiredLock==SQLITE_SHM_READ
       || desiredLock==SQLITE_SHM_WRITE
       || desiredLock==SQLITE_SHM_CHECKPOINT
       || desiredLock==SQLITE_SHM_RECOVER );

  /* Return directly if this is just a lock state query, or if
  ** the connection is already in the desired locking state.
  */
  if( desiredLock==p->lockState
   || (desiredLock==SQLITE_SHM_READ && p->lockState==SQLITE_SHM_READ_FULL)
  ){
    OSTRACE(("SHM-LOCK shmid-%d, pid-%d request %s and got %s\n",
             p->id, getpid(), azLkName[desiredLock], azLkName[p->lockState]));
    if( pGotLock ) *pGotLock = p->lockState;
    return SQLITE_OK;
  }

  OSTRACE(("SHM-LOCK shmid-%d, pid-%d request %s->%s\n",
            p->id, getpid(), azLkName[p->lockState], azLkName[desiredLock]));
  
  if( desiredLock==SQLITE_SHM_RECOVER && !p->hasMutexBuf ){
    assert( sqlite3_mutex_notheld(pShmNode->mutex) );
    sqlite3_mutex_enter(pShmNode->mutexBuf);
    p->hasMutexBuf = 1;
  }
  sqlite3_mutex_enter(pShmNode->mutex);
  switch( desiredLock ){
    case SQLITE_SHM_UNLOCK: {
      assert( p->lockState!=SQLITE_SHM_RECOVER );
      unixShmUnlock(pShmNode, p, UNIX_SHM_A|UNIX_SHM_B|UNIX_SHM_C|UNIX_SHM_D);
      rc = SQLITE_OK;
      p->lockState = SQLITE_SHM_UNLOCK;
      break;
    }
    case SQLITE_SHM_READ: {
      if( p->lockState==SQLITE_SHM_UNLOCK ){
        int nAttempt;
        rc = SQLITE_BUSY;
        assert( p->lockState==SQLITE_SHM_UNLOCK );
        for(nAttempt=0; nAttempt<5 && rc==SQLITE_BUSY; nAttempt++){
          rc = unixShmSharedLock(pShmNode, p, UNIX_SHM_A|UNIX_SHM_B);
          if( rc==SQLITE_BUSY ){
            rc = unixShmSharedLock(pShmNode, p, UNIX_SHM_D);
            if( rc==SQLITE_OK ){
              p->lockState = SQLITE_SHM_READ_FULL;
            }
          }else{
            unixShmUnlock(pShmNode, p, UNIX_SHM_B);
            p->lockState = SQLITE_SHM_READ;
          }
        }
      }else{
       assert( p->lockState==SQLITE_SHM_WRITE
               || p->lockState==SQLITE_SHM_RECOVER );
        rc = unixShmSharedLock(pShmNode, p, UNIX_SHM_A);
        unixShmUnlock(pShmNode, p, UNIX_SHM_C|UNIX_SHM_D);
        p->lockState = SQLITE_SHM_READ;
      }
      break;
    }
    case SQLITE_SHM_WRITE: {
      assert( p->lockState==SQLITE_SHM_READ 
              || p->lockState==SQLITE_SHM_READ_FULL );
      rc = unixShmExclusiveLock(pShmNode, p, UNIX_SHM_C|UNIX_SHM_D);
      if( rc==SQLITE_OK ){
        p->lockState = SQLITE_SHM_WRITE;
      }
      break;
    }
    case SQLITE_SHM_CHECKPOINT: {
      assert( p->lockState==SQLITE_SHM_UNLOCK
           || p->lockState==SQLITE_SHM_PENDING
      );
      if( p->lockState==SQLITE_SHM_UNLOCK ){
        rc = unixShmExclusiveLock(pShmNode, p, UNIX_SHM_B|UNIX_SHM_C);
        if( rc==SQLITE_OK ){
          p->lockState = SQLITE_SHM_PENDING;
        }
      }
      if( p->lockState==SQLITE_SHM_PENDING ){
        rc = unixShmExclusiveLock(pShmNode, p, UNIX_SHM_A);
        if( rc==SQLITE_OK ){
          p->lockState = SQLITE_SHM_CHECKPOINT;
        }
      }
      break;
    }
    default: {
      assert( desiredLock==SQLITE_SHM_RECOVER );
      assert( p->lockState==SQLITE_SHM_READ
           || p->lockState==SQLITE_SHM_READ_FULL
      );
      assert( sqlite3_mutex_held(pShmNode->mutexBuf) );
      rc = unixShmExclusiveLock(pShmNode, p, UNIX_SHM_C);
      if( rc==SQLITE_OK ){
        p->lockState = SQLITE_SHM_RECOVER;
      }
      break;
    }
  }
  sqlite3_mutex_leave(pShmNode->mutex);
  OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %s\n",
           p->id, getpid(), azLkName[p->lockState]));
  if( pGotLock ) *pGotLock = p->lockState;
  return rc;
}

#else
# define unixShmOpen    0
# define unixShmSize    0
# define unixShmGet     0
# define unixShmRelease 0
# define unixShmLock    0
# define unixShmClose   0
#endif /* #ifndef SQLITE_OMIT_WAL */

/*
** Here ends the implementation of all sqlite3_file methods.
**
********************** End sqlite3_file Methods *******************************
******************************************************************************/

/*
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**
**   *  A constant sqlite3_io_methods object call METHOD that has locking
**      methods CLOSE, LOCK, UNLOCK, CKRESLOCK.
**
**   *  An I/O method finder function called FINDER that returns a pointer
**      to the METHOD object in the previous bullet.
*/
#define IOMETHODS(FINDER, METHOD, CLOSE, LOCK, UNLOCK, CKLOCK)               \
static const sqlite3_io_methods METHOD = {                                   \
   1,                          /* iVersion */                                \
   CLOSE,                      /* xClose */                                  \
   unixRead,                   /* xRead */                                   \
   unixWrite,                  /* xWrite */                                  \
   unixTruncate,               /* xTruncate */                               \
   unixSync,                   /* xSync */                                   \
   unixFileSize,               /* xFileSize */                               \
   LOCK,                       /* xLock */                                   \
   UNLOCK,                     /* xUnlock */                                 \
   CKLOCK,                     /* xCheckReservedLock */                      \
   unixFileControl,            /* xFileControl */                            \
   unixSectorSize,             /* xSectorSize */                             \
   unixDeviceCharacteristics   /* xDeviceCapabilities */                     \






};                                                                           \
static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){   \
  UNUSED_PARAMETER(z); UNUSED_PARAMETER(p);                                  \
  return &METHOD;                                                            \
}                                                                            \
static const sqlite3_io_methods *(*const FINDER)(const char*,unixFile *p)    \
    = FINDER##Impl;

/*
** Here are all of the sqlite3_io_methods objects for each of the
** locking strategies.  Functions that return pointers to these methods
** are also created.
*/
IOMETHODS(
  posixIoFinder,            /* Finder function name */
  posixIoMethods,           /* sqlite3_io_methods object name */

  unixClose,                /* xClose method */
  unixLock,                 /* xLock method */
  unixUnlock,               /* xUnlock method */
  unixCheckReservedLock     /* xCheckReservedLock method */
)
IOMETHODS(
  nolockIoFinder,           /* Finder function name */
  nolockIoMethods,          /* sqlite3_io_methods object name */

  nolockClose,              /* xClose method */
  nolockLock,               /* xLock method */
  nolockUnlock,             /* xUnlock method */
  nolockCheckReservedLock   /* xCheckReservedLock method */
)
IOMETHODS(
  dotlockIoFinder,          /* Finder function name */
  dotlockIoMethods,         /* sqlite3_io_methods object name */

  dotlockClose,             /* xClose method */
  dotlockLock,              /* xLock method */
  dotlockUnlock,            /* xUnlock method */
  dotlockCheckReservedLock  /* xCheckReservedLock method */
)

#if SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORKS
IOMETHODS(
  flockIoFinder,            /* Finder function name */
  flockIoMethods,           /* sqlite3_io_methods object name */

  flockClose,               /* xClose method */
  flockLock,                /* xLock method */
  flockUnlock,              /* xUnlock method */
  flockCheckReservedLock    /* xCheckReservedLock method */
)
#endif

#if OS_VXWORKS
IOMETHODS(
  semIoFinder,              /* Finder function name */
  semIoMethods,             /* sqlite3_io_methods object name */

  semClose,                 /* xClose method */
  semLock,                  /* xLock method */
  semUnlock,                /* xUnlock method */
  semCheckReservedLock      /* xCheckReservedLock method */
)
#endif

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
IOMETHODS(
  afpIoFinder,              /* Finder function name */
  afpIoMethods,             /* sqlite3_io_methods object name */

  afpClose,                 /* xClose method */
  afpLock,                  /* xLock method */
  afpUnlock,                /* xUnlock method */
  afpCheckReservedLock      /* xCheckReservedLock method */
)
#endif








|

|











|
>
>
>
>
>
>
















>








>








>










>











>











>







3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
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3936
3937
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3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
**
**   *  A constant sqlite3_io_methods object call METHOD that has locking
**      methods CLOSE, LOCK, UNLOCK, CKRESLOCK.
**
**   *  An I/O method finder function called FINDER that returns a pointer
**      to the METHOD object in the previous bullet.
*/
#define IOMETHODS(FINDER, METHOD, VERSION, CLOSE, LOCK, UNLOCK, CKLOCK)      \
static const sqlite3_io_methods METHOD = {                                   \
   VERSION,                    /* iVersion */                                \
   CLOSE,                      /* xClose */                                  \
   unixRead,                   /* xRead */                                   \
   unixWrite,                  /* xWrite */                                  \
   unixTruncate,               /* xTruncate */                               \
   unixSync,                   /* xSync */                                   \
   unixFileSize,               /* xFileSize */                               \
   LOCK,                       /* xLock */                                   \
   UNLOCK,                     /* xUnlock */                                 \
   CKLOCK,                     /* xCheckReservedLock */                      \
   unixFileControl,            /* xFileControl */                            \
   unixSectorSize,             /* xSectorSize */                             \
   unixDeviceCharacteristics,  /* xDeviceCapabilities */                     \
   unixShmOpen,                /* xShmOpen */                                \
   unixShmSize,                /* xShmSize */                                \
   unixShmGet,                 /* xShmGet */                                 \
   unixShmRelease,             /* xShmRelease */                             \
   unixShmLock,                /* xShmLock */                                \
   unixShmClose                /* xShmClose */                               \
};                                                                           \
static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){   \
  UNUSED_PARAMETER(z); UNUSED_PARAMETER(p);                                  \
  return &METHOD;                                                            \
}                                                                            \
static const sqlite3_io_methods *(*const FINDER)(const char*,unixFile *p)    \
    = FINDER##Impl;

/*
** Here are all of the sqlite3_io_methods objects for each of the
** locking strategies.  Functions that return pointers to these methods
** are also created.
*/
IOMETHODS(
  posixIoFinder,            /* Finder function name */
  posixIoMethods,           /* sqlite3_io_methods object name */
  2,                        /* ShmOpen is enabled */
  unixClose,                /* xClose method */
  unixLock,                 /* xLock method */
  unixUnlock,               /* xUnlock method */
  unixCheckReservedLock     /* xCheckReservedLock method */
)
IOMETHODS(
  nolockIoFinder,           /* Finder function name */
  nolockIoMethods,          /* sqlite3_io_methods object name */
  1,                        /* ShmOpen is disabled */
  nolockClose,              /* xClose method */
  nolockLock,               /* xLock method */
  nolockUnlock,             /* xUnlock method */
  nolockCheckReservedLock   /* xCheckReservedLock method */
)
IOMETHODS(
  dotlockIoFinder,          /* Finder function name */
  dotlockIoMethods,         /* sqlite3_io_methods object name */
  1,                        /* ShmOpen is disabled */
  dotlockClose,             /* xClose method */
  dotlockLock,              /* xLock method */
  dotlockUnlock,            /* xUnlock method */
  dotlockCheckReservedLock  /* xCheckReservedLock method */
)

#if SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORKS
IOMETHODS(
  flockIoFinder,            /* Finder function name */
  flockIoMethods,           /* sqlite3_io_methods object name */
  1,                        /* ShmOpen is disabled */
  flockClose,               /* xClose method */
  flockLock,                /* xLock method */
  flockUnlock,              /* xUnlock method */
  flockCheckReservedLock    /* xCheckReservedLock method */
)
#endif

#if OS_VXWORKS
IOMETHODS(
  semIoFinder,              /* Finder function name */
  semIoMethods,             /* sqlite3_io_methods object name */
  1,                        /* ShmOpen is disabled */
  semClose,                 /* xClose method */
  semLock,                  /* xLock method */
  semUnlock,                /* xUnlock method */
  semCheckReservedLock      /* xCheckReservedLock method */
)
#endif

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
IOMETHODS(
  afpIoFinder,              /* Finder function name */
  afpIoMethods,             /* sqlite3_io_methods object name */
  1,                        /* ShmOpen is disabled */
  afpClose,                 /* xClose method */
  afpLock,                  /* xLock method */
  afpUnlock,                /* xUnlock method */
  afpCheckReservedLock      /* xCheckReservedLock method */
)
#endif

3539
3540
3541
3542
3543
3544
3545

3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557

3558
3559
3560
3561
3562
3563
3564
static int proxyClose(sqlite3_file*);
static int proxyLock(sqlite3_file*, int);
static int proxyUnlock(sqlite3_file*, int);
static int proxyCheckReservedLock(sqlite3_file*, int*);
IOMETHODS(
  proxyIoFinder,            /* Finder function name */
  proxyIoMethods,           /* sqlite3_io_methods object name */

  proxyClose,               /* xClose method */
  proxyLock,                /* xLock method */
  proxyUnlock,              /* xUnlock method */
  proxyCheckReservedLock    /* xCheckReservedLock method */
)
#endif

/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
IOMETHODS(
  nfsIoFinder,               /* Finder function name */
  nfsIoMethods,              /* sqlite3_io_methods object name */

  unixClose,                 /* xClose method */
  unixLock,                  /* xLock method */
  nfsUnlock,                 /* xUnlock method */
  unixCheckReservedLock      /* xCheckReservedLock method */
)
#endif








>












>







4037
4038
4039
4040
4041
4042
4043
4044
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4046
4047
4048
4049
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4051
4052
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4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
static int proxyClose(sqlite3_file*);
static int proxyLock(sqlite3_file*, int);
static int proxyUnlock(sqlite3_file*, int);
static int proxyCheckReservedLock(sqlite3_file*, int*);
IOMETHODS(
  proxyIoFinder,            /* Finder function name */
  proxyIoMethods,           /* sqlite3_io_methods object name */
  1,                        /* ShmOpen is disabled */
  proxyClose,               /* xClose method */
  proxyLock,                /* xLock method */
  proxyUnlock,              /* xUnlock method */
  proxyCheckReservedLock    /* xCheckReservedLock method */
)
#endif

/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
IOMETHODS(
  nfsIoFinder,               /* Finder function name */
  nfsIoMethods,              /* sqlite3_io_methods object name */
  1,                         /* ShmOpen is disabled */
  unixClose,                 /* xClose method */
  unixLock,                  /* xLock method */
  nfsUnlock,                 /* xUnlock method */
  unixCheckReservedLock      /* xCheckReservedLock method */
)
#endif

3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710


3711
3712
3713
3714
3715
3716
3717
  int noLock,             /* Omit locking if true */
  int isDelete            /* Delete on close if true */
){
  const sqlite3_io_methods *pLockingStyle;
  unixFile *pNew = (unixFile *)pId;
  int rc = SQLITE_OK;

  assert( pNew->pLock==NULL );
  assert( pNew->pOpen==NULL );

  /* Parameter isDelete is only used on vxworks. Express this explicitly 
  ** here to prevent compiler warnings about unused parameters.
  */
  UNUSED_PARAMETER(isDelete);

  OSTRACE3("OPEN    %-3d %s\n", h, zFilename);    
  pNew->h = h;
  pNew->dirfd = dirfd;
  SET_THREADID(pNew);
  pNew->fileFlags = 0;



#if OS_VXWORKS
  pNew->pId = vxworksFindFileId(zFilename);
  if( pNew->pId==0 ){
    noLock = 1;
    rc = SQLITE_NOMEM;
  }







|
<






|


<

>
>







4191
4192
4193
4194
4195
4196
4197
4198

4199
4200
4201
4202
4203
4204
4205
4206
4207

4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
  int noLock,             /* Omit locking if true */
  int isDelete            /* Delete on close if true */
){
  const sqlite3_io_methods *pLockingStyle;
  unixFile *pNew = (unixFile *)pId;
  int rc = SQLITE_OK;

  assert( pNew->pInode==NULL );


  /* Parameter isDelete is only used on vxworks. Express this explicitly 
  ** here to prevent compiler warnings about unused parameters.
  */
  UNUSED_PARAMETER(isDelete);

  OSTRACE(("OPEN    %-3d %s\n", h, zFilename));
  pNew->h = h;
  pNew->dirfd = dirfd;

  pNew->fileFlags = 0;
  assert( zFilename==0 || zFilename[0]=='/' );  /* Never a relative pathname */
  pNew->zPath = zFilename;

#if OS_VXWORKS
  pNew->pId = vxworksFindFileId(zFilename);
  if( pNew->pId==0 ){
    noLock = 1;
    rc = SQLITE_NOMEM;
  }
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757

  if( pLockingStyle == &posixIoMethods
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
    || pLockingStyle == &nfsIoMethods
#endif
  ){
    unixEnterMutex();
    rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
    if( rc!=SQLITE_OK ){
      /* If an error occured in findLockInfo(), close the file descriptor
      ** immediately, before releasing the mutex. findLockInfo() may fail
      ** in two scenarios:
      **
      **   (a) A call to fstat() failed.
      **   (b) A malloc failed.
      **
      ** Scenario (b) may only occur if the process is holding no other
      ** file descriptors open on the same file. If there were other file
      ** descriptors on this file, then no malloc would be required by
      ** findLockInfo(). If this is the case, it is quite safe to close
      ** handle h - as it is guaranteed that no posix locks will be released
      ** by doing so.
      **
      ** If scenario (a) caused the error then things are not so safe. The
      ** implicit assumption here is that if fstat() fails, things are in
      ** such bad shape that dropping a lock or two doesn't matter much.
      */







|

|
|








|







4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257

  if( pLockingStyle == &posixIoMethods
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
    || pLockingStyle == &nfsIoMethods
#endif
  ){
    unixEnterMutex();
    rc = findInodeInfo(pNew, &pNew->pInode);
    if( rc!=SQLITE_OK ){
      /* If an error occured in findInodeInfo(), close the file descriptor
      ** immediately, before releasing the mutex. findInodeInfo() may fail
      ** in two scenarios:
      **
      **   (a) A call to fstat() failed.
      **   (b) A malloc failed.
      **
      ** Scenario (b) may only occur if the process is holding no other
      ** file descriptors open on the same file. If there were other file
      ** descriptors on this file, then no malloc would be required by
      ** findInodeInfo(). If this is the case, it is quite safe to close
      ** handle h - as it is guaranteed that no posix locks will be released
      ** by doing so.
      **
      ** If scenario (a) caused the error then things are not so safe. The
      ** implicit assumption here is that if fstat() fails, things are in
      ** such bad shape that dropping a lock or two doesn't matter much.
      */
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
      /* NB: zFilename exists and remains valid until the file is closed
      ** according to requirement F11141.  So we do not need to make a
      ** copy of the filename. */
      pCtx->dbPath = zFilename;
      pCtx->reserved = 0;
      srandomdev();
      unixEnterMutex();
      rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
      if( rc!=SQLITE_OK ){
        sqlite3_free(pNew->lockingContext);
        close(h);
        h = -1;
      }
      unixLeaveMutex();        
    }







|







4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
      /* NB: zFilename exists and remains valid until the file is closed
      ** according to requirement F11141.  So we do not need to make a
      ** copy of the filename. */
      pCtx->dbPath = zFilename;
      pCtx->reserved = 0;
      srandomdev();
      unixEnterMutex();
      rc = findInodeInfo(pNew, &pNew->pInode);
      if( rc!=SQLITE_OK ){
        sqlite3_free(pNew->lockingContext);
        close(h);
        h = -1;
      }
      unixLeaveMutex();        
    }
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832

#if OS_VXWORKS
  else if( pLockingStyle == &semIoMethods ){
    /* Named semaphore locking uses the file path so it needs to be
    ** included in the semLockingContext
    */
    unixEnterMutex();
    rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
    if( (rc==SQLITE_OK) && (pNew->pOpen->pSem==NULL) ){
      char *zSemName = pNew->pOpen->aSemName;
      int n;
      sqlite3_snprintf(MAX_PATHNAME, zSemName, "/%s.sem",
                       pNew->pId->zCanonicalName);
      for( n=1; zSemName[n]; n++ )
        if( zSemName[n]=='/' ) zSemName[n] = '_';
      pNew->pOpen->pSem = sem_open(zSemName, O_CREAT, 0666, 1);
      if( pNew->pOpen->pSem == SEM_FAILED ){
        rc = SQLITE_NOMEM;
        pNew->pOpen->aSemName[0] = '\0';
      }
    }
    unixLeaveMutex();
  }
#endif
  
  pNew->lastErrno = 0;







|
|
|





|
|

|







4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332

#if OS_VXWORKS
  else if( pLockingStyle == &semIoMethods ){
    /* Named semaphore locking uses the file path so it needs to be
    ** included in the semLockingContext
    */
    unixEnterMutex();
    rc = findInodeInfo(pNew, &pNew->pInode);
    if( (rc==SQLITE_OK) && (pNew->pInode->pSem==NULL) ){
      char *zSemName = pNew->pInode->aSemName;
      int n;
      sqlite3_snprintf(MAX_PATHNAME, zSemName, "/%s.sem",
                       pNew->pId->zCanonicalName);
      for( n=1; zSemName[n]; n++ )
        if( zSemName[n]=='/' ) zSemName[n] = '_';
      pNew->pInode->pSem = sem_open(zSemName, O_CREAT, 0666, 1);
      if( pNew->pInode->pSem == SEM_FAILED ){
        rc = SQLITE_NOMEM;
        pNew->pInode->aSemName[0] = '\0';
      }
    }
    unixLeaveMutex();
  }
#endif
  
  pNew->lastErrno = 0;
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
  if( ii>0 ){
    zDirname[ii] = '\0';
    fd = open(zDirname, O_RDONLY|O_BINARY, 0);
    if( fd>=0 ){
#ifdef FD_CLOEXEC
      fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
#endif
      OSTRACE3("OPENDIR %-3d %s\n", fd, zDirname);
    }
  }
  *pFd = fd;
  return (fd>=0?SQLITE_OK:SQLITE_CANTOPEN_BKPT);
}

/*







|







4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
  if( ii>0 ){
    zDirname[ii] = '\0';
    fd = open(zDirname, O_RDONLY|O_BINARY, 0);
    if( fd>=0 ){
#ifdef FD_CLOEXEC
      fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
#endif
      OSTRACE(("OPENDIR %-3d %s\n", fd, zDirname));
    }
  }
  *pFd = fd;
  return (fd>=0?SQLITE_OK:SQLITE_CANTOPEN_BKPT);
}

/*
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
  ** For this reason, if an error occurs in the stat() call here, it is
  ** ignored and -1 is returned. The caller will try to open a new file
  ** descriptor on the same path, fail, and return an error to SQLite.
  **
  ** Even if a subsequent open() call does succeed, the consequences of
  ** not searching for a resusable file descriptor are not dire.  */
  if( 0==stat(zPath, &sStat) ){
    struct unixOpenCnt *pOpen;

    unixEnterMutex();
    pOpen = openList;
    while( pOpen && (pOpen->fileId.dev!=sStat.st_dev
                     || pOpen->fileId.ino!=sStat.st_ino) ){
       pOpen = pOpen->pNext;
    }
    if( pOpen ){
      UnixUnusedFd **pp;
      for(pp=&pOpen->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext));
      pUnused = *pp;
      if( pUnused ){
        *pp = pUnused->pNext;
      }
    }
    unixLeaveMutex();
  }







|


|
|
|
|

|

|







4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
  ** For this reason, if an error occurs in the stat() call here, it is
  ** ignored and -1 is returned. The caller will try to open a new file
  ** descriptor on the same path, fail, and return an error to SQLite.
  **
  ** Even if a subsequent open() call does succeed, the consequences of
  ** not searching for a resusable file descriptor are not dire.  */
  if( 0==stat(zPath, &sStat) ){
    unixInodeInfo *pInode;

    unixEnterMutex();
    pInode = inodeList;
    while( pInode && (pInode->fileId.dev!=sStat.st_dev
                     || pInode->fileId.ino!=sStat.st_ino) ){
       pInode = pInode->pNext;
    }
    if( pInode ){
      UnixUnusedFd **pp;
      for(pp=&pInode->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext));
      pUnused = *pp;
      if( pUnused ){
        *pp = pUnused->pNext;
      }
    }
    unixLeaveMutex();
  }
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  if( isCreate )    openFlags |= O_CREAT;
  if( isExclusive ) openFlags |= (O_EXCL|O_NOFOLLOW);
  openFlags |= (O_LARGEFILE|O_BINARY);

  if( fd<0 ){
    mode_t openMode = (isDelete?0600:SQLITE_DEFAULT_FILE_PERMISSIONS);
    fd = open(zName, openFlags, openMode);
    OSTRACE4("OPENX   %-3d %s 0%o\n", fd, zName, openFlags);
    if( fd<0 && errno!=EISDIR && isReadWrite && !isExclusive ){
      /* Failed to open the file for read/write access. Try read-only. */
      flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
      openFlags &= ~(O_RDWR|O_CREAT);
      flags |= SQLITE_OPEN_READONLY;
      openFlags |= O_RDONLY;
      fd = open(zName, openFlags, openMode);







|







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  if( isCreate )    openFlags |= O_CREAT;
  if( isExclusive ) openFlags |= (O_EXCL|O_NOFOLLOW);
  openFlags |= (O_LARGEFILE|O_BINARY);

  if( fd<0 ){
    mode_t openMode = (isDelete?0600:SQLITE_DEFAULT_FILE_PERMISSIONS);
    fd = open(zName, openFlags, openMode);
    OSTRACE(("OPENX   %-3d %s 0%o\n", fd, zName, openFlags));
    if( fd<0 && errno!=EISDIR && isReadWrite && !isExclusive ){
      /* Failed to open the file for read/write access. Try read-only. */
      flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
      openFlags &= ~(O_RDWR|O_CREAT);
      flags |= SQLITE_OPEN_READONLY;
      openFlags |= O_RDONLY;
      fd = open(zName, openFlags, openMode);
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static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
  UNUSED_PARAMETER(NotUsed);
  UNUSED_PARAMETER(NotUsed2);
  UNUSED_PARAMETER(NotUsed3);
  return 0;
}

#ifndef SQLITE_OMIT_WAL

/* Forward reference */
typedef struct unixShm unixShm;
typedef struct unixShmFile unixShmFile;

/*
** Object used to represent a single file opened and mmapped to provide
** shared memory.  When multiple threads all reference the same
** log-summary, each thread has its own unixFile object, but they all
** point to a single instance of this object.  In other words, each
** log-summary is opened only once per process.
**
** unixMutexHeld() must be true when creating or destroying
** this object or while reading or writing the following fields:
**
**      nRef
**      pNext 
**
** The following fields are read-only after the object is created:
** 
**      fid
**      zFilename
**
** Either unixShmFile.mutex must be held or unixShmFile.nRef==0 and
** unixMutexHeld() is true when reading or writing any other field
** in this structure.
**
** To avoid deadlocks, mutex and mutexBuf are always released in the
** reverse order that they are acquired.  mutexBuf is always acquired
** first and released last.  This invariant is check by asserting
** sqlite3_mutex_notheld() on mutex whenever mutexBuf is acquired or
** released.
*/
struct unixShmFile {
  struct unixFileId fid;     /* Unique file identifier */
  sqlite3_mutex *mutex;      /* Mutex to access this object */
  sqlite3_mutex *mutexBuf;   /* Mutex to access zBuf[] */
  char *zFilename;           /* Name of the file */
  int h;                     /* Open file descriptor */
  int szMap;                 /* Size of the mapping of file into memory */
  char *pMMapBuf;            /* Where currently mmapped().  NULL if unmapped */
  int nRef;                  /* Number of unixShm objects pointing to this */
  unixShm *pFirst;           /* All unixShm objects pointing to this */
  unixShmFile *pNext;        /* Next in list of all unixShmFile objects */
#ifdef SQLITE_DEBUG
  u8 exclMask;               /* Mask of exclusive locks held */
  u8 sharedMask;             /* Mask of shared locks held */
  u8 nextShmId;              /* Next available unixShm.id value */
#endif
};

/*
** A global array of all unixShmFile objects.
**
** The unixMutexHeld() must be true while reading or writing this list.
*/
static unixShmFile *unixShmFileList = 0;

/*
** Structure used internally by this VFS to record the state of an
** open shared memory connection.
**
** unixShm.pFile->mutex must be held while reading or writing the
** unixShm.pNext and unixShm.locks[] elements.
**
** The unixShm.pFile element is initialized when the object is created
** and is read-only thereafter.
*/
struct unixShm {
  unixShmFile *pFile;        /* The underlying unixShmFile object */
  unixShm *pNext;            /* Next unixShm with the same unixShmFile */
  u8 lockState;              /* Current lock state */
  u8 hasMutex;               /* True if holding the unixShmFile mutex */
  u8 hasMutexBuf;            /* True if holding pFile->mutexBuf */
  u8 sharedMask;             /* Mask of shared locks held */
  u8 exclMask;               /* Mask of exclusive locks held */
#ifdef SQLITE_DEBUG
  u8 id;                     /* Id of this connection with its unixShmFile */
#endif
};

/*
** Size increment by which shared memory grows
*/
#define SQLITE_UNIX_SHM_INCR  4096

/*
** Constants used for locking
*/
#define UNIX_SHM_BASE      32        /* Byte offset of the first lock byte */
#define UNIX_SHM_DMS       0x01      /* Mask for Dead-Man-Switch lock */
#define UNIX_SHM_A         0x10      /* Mask for region locks... */
#define UNIX_SHM_B         0x20
#define UNIX_SHM_C         0x40
#define UNIX_SHM_D         0x80

#ifdef SQLITE_DEBUG
/*
** Return a pointer to a nul-terminated string in static memory that
** describes a locking mask.  The string is of the form "MSABCD" with
** each character representing a lock.  "M" for MUTEX, "S" for DMS, 
** and "A" through "D" for the region locks.  If a lock is held, the
** letter is shown.  If the lock is not held, the letter is converted
** to ".".
**
** This routine is for debugging purposes only and does not appear
** in a production build.
*/
static const char *unixShmLockString(u8 mask){
  static char zBuf[48];
  static int iBuf = 0;
  char *z;

  z = &zBuf[iBuf];
  iBuf += 8;
  if( iBuf>=sizeof(zBuf) ) iBuf = 0;

  z[0] = (mask & UNIX_SHM_DMS)   ? 'S' : '.';
  z[1] = (mask & UNIX_SHM_A)     ? 'A' : '.';
  z[2] = (mask & UNIX_SHM_B)     ? 'B' : '.';
  z[3] = (mask & UNIX_SHM_C)     ? 'C' : '.';
  z[4] = (mask & UNIX_SHM_D)     ? 'D' : '.';
  z[5] = 0;
  return z;
}
#endif /* SQLITE_DEBUG */

/*
** Apply posix advisory locks for all bytes identified in lockMask.
**
** lockMask might contain multiple bits but all bits are guaranteed
** to be contiguous.
**
** Locks block if the mask is exactly UNIX_SHM_C and are non-blocking
** otherwise.
*/
static int unixShmSystemLock(
  unixShmFile *pFile,   /* Apply locks to this open shared-memory segment */
  int lockType,         /* F_UNLCK, F_RDLCK, or F_WRLCK */
  u8 lockMask           /* Which bytes to lock or unlock */
){
  struct flock f;       /* The posix advisory locking structure */
  int lockOp;           /* The opcode for fcntl() */
  int i;                /* Offset into the locking byte range */
  int rc;               /* Result code form fcntl() */
  u8 mask;              /* Mask of bits in lockMask */

  /* Access to the unixShmFile object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) || pFile->nRef==0 );

  /* Initialize the locking parameters */
  memset(&f, 0, sizeof(f));
  f.l_type = lockType;
  f.l_whence = SEEK_SET;
  if( lockMask==UNIX_SHM_C && lockType!=F_UNLCK ){
    lockOp = F_SETLKW;
    OSTRACE(("SHM-LOCK requesting blocking lock\n"));
  }else{
    lockOp = F_SETLK;
  }

  /* Find the first bit in lockMask that is set */
  for(i=0, mask=0x01; mask!=0 && (lockMask&mask)==0; mask <<= 1, i++){}
  assert( mask!=0 );
  f.l_start = i+UNIX_SHM_BASE;
  f.l_len = 1;

  /* Extend the locking range for each additional bit that is set */
  mask <<= 1;
  while( mask!=0 && (lockMask & mask)!=0 ){
    f.l_len++;
    mask <<= 1;
  }

  /* Verify that all bits set in lockMask are contiguous */
  assert( mask==0 || (lockMask & ~(mask | (mask-1)))==0 );

  /* Acquire the system-level lock */
  rc = fcntl(pFile->h, lockOp, &f);
  rc = (rc!=(-1)) ? SQLITE_OK : SQLITE_BUSY;

  /* Update the global lock state and do debug tracing */
#ifdef SQLITE_DEBUG
  OSTRACE(("SHM-LOCK "));
  if( rc==SQLITE_OK ){
    if( lockType==F_UNLCK ){
      OSTRACE(("unlock ok"));
      pFile->exclMask &= ~lockMask;
      pFile->sharedMask &= ~lockMask;
    }else if( lockType==F_RDLCK ){
      OSTRACE(("read-lock ok"));
      pFile->exclMask &= ~lockMask;
      pFile->sharedMask |= lockMask;
    }else{
      assert( lockType==F_WRLCK );
      OSTRACE(("write-lock ok"));
      pFile->exclMask |= lockMask;
      pFile->sharedMask &= ~lockMask;
    }
  }else{
    if( lockType==F_UNLCK ){
      OSTRACE(("unlock failed"));
    }else if( lockType==F_RDLCK ){
      OSTRACE(("read-lock failed"));
    }else{
      assert( lockType==F_WRLCK );
      OSTRACE(("write-lock failed"));
    }
  }
  OSTRACE((" - change requested %s - afterwards %s:%s\n",
           unixShmLockString(lockMask),
           unixShmLockString(pFile->sharedMask),
           unixShmLockString(pFile->exclMask)));
#endif

  return rc;        
}

/*
** For connection p, unlock all of the locks identified by the unlockMask
** parameter.
*/
static int unixShmUnlock(
  unixShmFile *pFile,   /* The underlying shared-memory file */
  unixShm *p,           /* The connection to be unlocked */
  u8 unlockMask         /* Mask of locks to be unlocked */
){
  int rc;      /* Result code */
  unixShm *pX; /* For looping over all sibling connections */
  u8 allMask;  /* Union of locks held by connections other than "p" */

  /* Access to the unixShmFile object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) );

  /* Compute locks held by sibling connections */
  allMask = 0;
  for(pX=pFile->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
    allMask |= pX->sharedMask;
  }

  /* Unlock the system-level locks */
  if( (unlockMask & allMask)!=unlockMask ){
    rc = unixShmSystemLock(pFile, F_UNLCK, unlockMask & ~allMask);
  }else{
    rc = SQLITE_OK;
  }

  /* Undo the local locks */
  if( rc==SQLITE_OK ){
    p->exclMask &= ~unlockMask;
    p->sharedMask &= ~unlockMask;
  } 
  return rc;
}

/*
** Get reader locks for connection p on all locks in the readMask parameter.
*/
static int unixShmSharedLock(
  unixShmFile *pFile,   /* The underlying shared-memory file */
  unixShm *p,           /* The connection to get the shared locks */
  u8 readMask           /* Mask of shared locks to be acquired */
){
  int rc;        /* Result code */
  unixShm *pX;   /* For looping over all sibling connections */
  u8 allShared;  /* Union of locks held by connections other than "p" */

  /* Access to the unixShmFile object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) );

  /* Find out which shared locks are already held by sibling connections.
  ** If any sibling already holds an exclusive lock, go ahead and return
  ** SQLITE_BUSY.
  */
  allShared = 0;
  for(pX=pFile->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    if( (pX->exclMask & readMask)!=0 ) return SQLITE_BUSY;
    allShared |= pX->sharedMask;
  }

  /* Get shared locks at the system level, if necessary */
  if( (~allShared) & readMask ){
    rc = unixShmSystemLock(pFile, F_RDLCK, readMask);
  }else{
    rc = SQLITE_OK;
  }

  /* Get the local shared locks */
  if( rc==SQLITE_OK ){
    p->sharedMask |= readMask;
  }
  return rc;
}

/*
** For connection p, get an exclusive lock on all locks identified in
** the writeMask parameter.
*/
static int unixShmExclusiveLock(
  unixShmFile *pFile,    /* The underlying shared-memory file */
  unixShm *p,            /* The connection to get the exclusive locks */
  u8 writeMask           /* Mask of exclusive locks to be acquired */
){
  int rc;        /* Result code */
  unixShm *pX;   /* For looping over all sibling connections */

  /* Access to the unixShmFile object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) );

  /* Make sure no sibling connections hold locks that will block this
  ** lock.  If any do, return SQLITE_BUSY right away.
  */
  for(pX=pFile->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    if( (pX->exclMask & writeMask)!=0 ) return SQLITE_BUSY;
    if( (pX->sharedMask & writeMask)!=0 ) return SQLITE_BUSY;
  }

  /* Get the exclusive locks at the system level.  Then if successful
  ** also mark the local connection as being locked.
  */
  rc = unixShmSystemLock(pFile, F_WRLCK, writeMask);
  if( rc==SQLITE_OK ){
    p->sharedMask &= ~writeMask;
    p->exclMask |= writeMask;
  }
  return rc;
}

/*
** Purge the unixShmFileList list of all entries with unixShmFile.nRef==0.
**
** This is not a VFS shared-memory method; it is a utility function called
** by VFS shared-memory methods.
*/
static void unixShmPurge(void){
  unixShmFile **pp;
  unixShmFile *p;
  assert( unixMutexHeld() );
  pp = &unixShmFileList;
  while( (p = *pp)!=0 ){
    if( p->nRef==0 ){
      if( p->mutex ) sqlite3_mutex_free(p->mutex);
      if( p->mutexBuf ) sqlite3_mutex_free(p->mutexBuf);
      if( p->h>=0 ) close(p->h);
      *pp = p->pNext;
      sqlite3_free(p);
    }else{
      pp = &p->pNext;
    }
  }
}

/*
** Open a shared-memory area.  This particular implementation uses
** mmapped files.
**
** zName is a filename used to identify the shared-memory area.  The
** implementation does not (and perhaps should not) use this name
** directly, but rather use it as a template for finding an appropriate
** name for the shared-memory storage.  In this implementation, the
** string "-index" is appended to zName and used as the name of the
** mmapped file.
**
** When opening a new shared-memory file, if no other instances of that
** file are currently open, in this process or in other processes, then
** the file must be truncated to zero length or have its header cleared.
*/
static int unixShmOpen(
  sqlite3_vfs *pVfs,    /* The VFS */
  const char *zName,    /* Name of the corresponding database file */
  sqlite3_shm **pShm    /* Write the unixShm object created here */
){
  struct unixShm *p = 0;             /* The connection to be opened */
  struct unixShmFile *pFile = 0;     /* The underlying mmapped file */
  int rc;                            /* Result code */
  struct unixFileId fid;             /* Unix file identifier */
  struct unixShmFile *pNew;          /* Newly allocated pFile */
  struct stat sStat;                 /* Result from stat() an fstat() */
  int nName;                         /* Size of zName in bytes */

  /* Allocate space for the new sqlite3_shm object.  Also speculatively
  ** allocate space for a new unixShmFile and filename.
  */
  p = sqlite3_malloc( sizeof(*p) );
  if( p==0 ) return SQLITE_NOMEM;
  memset(p, 0, sizeof(*p));
  nName = strlen(zName);
  pNew = sqlite3_malloc( sizeof(*pFile) + nName + 15 );
  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_NOMEM;
  }
  memset(pNew, 0, sizeof(*pNew));
  pNew->zFilename = (char*)&pNew[1];
  sqlite3_snprintf(nName+11, pNew->zFilename, "%s-wal-index", zName);

  /* Look to see if there is an existing unixShmFile that can be used.
  ** If no matching unixShmFile currently exists, create a new one.
  */
  unixEnterMutex();
  rc = stat(pNew->zFilename, &sStat);
  if( rc==0 ){
    memset(&fid, 0, sizeof(fid));
    fid.dev = sStat.st_dev;
    fid.ino = sStat.st_ino;
    for(pFile = unixShmFileList; pFile; pFile=pFile->pNext){
      if( memcmp(&pFile->fid, &fid, sizeof(fid))==0 ) break;
    }
  }
  if( pFile ){
    sqlite3_free(pNew);
  }else{
    pFile = pNew;
    pNew = 0;
    pFile->h = -1;
    pFile->pNext = unixShmFileList;
    unixShmFileList = pFile;

    pFile->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pFile->mutex==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    pFile->mutexBuf = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pFile->mutexBuf==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }

    pFile->h = open(pFile->zFilename, O_RDWR|O_CREAT, 0664);
    if( pFile->h<0 ){
      rc = SQLITE_CANTOPEN_BKPT;
      goto shm_open_err;
    }

    rc = fstat(pFile->h, &sStat);
    if( rc ){
      rc = SQLITE_CANTOPEN_BKPT;
      goto shm_open_err;
    }
    pFile->fid.dev = sStat.st_dev;
    pFile->fid.ino = sStat.st_ino;

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    if( unixShmSystemLock(pFile, F_WRLCK, UNIX_SHM_DMS)==SQLITE_OK ){
      if( ftruncate(pFile->h, 0) ){
        rc = SQLITE_IOERR;
      }
    }
    if( rc==SQLITE_OK ){
      rc = unixShmSystemLock(pFile, F_RDLCK, UNIX_SHM_DMS);
    }
    if( rc ) goto shm_open_err;
  }

  /* Make the new connection a child of the unixShmFile */
  p->pFile = pFile;
  p->pNext = pFile->pFirst;
#ifdef SQLITE_DEBUG
  p->id = pFile->nextShmId++;
#endif
  pFile->pFirst = p;
  pFile->nRef++;
  *pShm = (sqlite3_shm*)p;
  unixLeaveMutex();
  return SQLITE_OK;

  /* Jump here on any error */
shm_open_err:
  unixShmPurge();                 /* This call frees pFile if required */
  sqlite3_free(p);
  sqlite3_free(pNew);
  *pShm = 0;
  unixLeaveMutex();
  return rc;
}

/*
** Close a connection to shared-memory.  Delete the underlying 
** storage if deleteFlag is true.
*/
static int unixShmClose(
  sqlite3_vfs *pVfs,         /* The VFS */
  sqlite3_shm *pSharedMem,   /* The shared-memory to be closed */
  int deleteFlag             /* Delete after closing if true */
){
  unixShm *p;            /* The connection to be closed */
  unixShmFile *pFile;    /* The underlying shared-memory file */
  unixShm **pp;          /* For looping over sibling connections */

  UNUSED_PARAMETER(pVfs);
  if( pSharedMem==0 ) return SQLITE_OK;
  p = (struct unixShm*)pSharedMem;
  pFile = p->pFile;

  /* Verify that the connection being closed holds no locks */
  assert( p->exclMask==0 );
  assert( p->sharedMask==0 );

  /* Remove connection p from the set of connections associated with pFile */
  sqlite3_mutex_enter(pFile->mutex);
  for(pp=&pFile->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
  *pp = p->pNext;

  /* Free the connection p */
  sqlite3_free(p);
  sqlite3_mutex_leave(pFile->mutex);

  /* If pFile->nRef has reached 0, then close the underlying
  ** shared-memory file, too */
  unixEnterMutex();
  assert( pFile->nRef>0 );
  pFile->nRef--;
  if( pFile->nRef==0 ){
    if( deleteFlag ) unlink(pFile->zFilename);
    unixShmPurge();
  }
  unixLeaveMutex();

  return SQLITE_OK;
}

/*
** Query and/or changes the size of the underlying storage for
** a shared-memory segment.  The reqSize parameter is the new size
** of the underlying storage, or -1 to do just a query.  The size
** of the underlying storage (after resizing if resizing occurs) is
** written into pNewSize.
**
** This routine does not (necessarily) change the size of the mapping 
** of the underlying storage into memory.  Use xShmGet() to change
** the mapping size.
**
** The reqSize parameter is the minimum size requested.  The implementation
** is free to expand the storage to some larger amount if it chooses.
*/
static int unixShmSize(
  sqlite3_vfs *pVfs,        /* The VFS */
  sqlite3_shm *pSharedMem,  /* Pointer returned by unixShmOpen() */
  int reqSize,              /* Requested size.  -1 for query only */
  int *pNewSize             /* Write new size here */
){
  unixShm *p = (unixShm*)pSharedMem;
  unixShmFile *pFile = p->pFile;
  int rc = SQLITE_OK;
  struct stat sStat;

  UNUSED_PARAMETER(pVfs);

  if( reqSize>=0 ){
    reqSize = (reqSize + SQLITE_UNIX_SHM_INCR - 1)/SQLITE_UNIX_SHM_INCR;
    reqSize *= SQLITE_UNIX_SHM_INCR;
    rc = ftruncate(pFile->h, reqSize);
  }
  if( fstat(pFile->h, &sStat)==0 ){
    *pNewSize = (int)sStat.st_size;
  }else{
    *pNewSize = 0;
    rc = SQLITE_IOERR;
  }
  return rc;
}


/*
** Map the shared storage into memory.  The minimum size of the
** mapping should be reqMapSize if reqMapSize is positive.  If
** reqMapSize is zero or negative, the implementation can choose
** whatever mapping size is convenient.
**
** *ppBuf is made to point to the memory which is a mapping of the
** underlying storage.  A mutex is acquired to prevent other threads
** from running while *ppBuf is in use in order to prevent other threads
** remapping *ppBuf out from under this thread.  The unixShmRelease()
** call will release the mutex.  However, if the lock state is CHECKPOINT,
** the mutex is not acquired because CHECKPOINT will never remap the
** buffer.  RECOVER might remap, though, so CHECKPOINT will acquire
** the mutex if and when it promotes to RECOVER.
**
** RECOVER needs to be atomic.  The same mutex that prevents *ppBuf from
** being remapped also prevents more than one thread from being in
** RECOVER at a time.  But, RECOVER sometimes wants to remap itself.
** To prevent RECOVER from losing its lock while remapping, the
** mutex is not released by unixShmRelease() when in RECOVER.
**
** *pNewMapSize is set to the size of the mapping.
**
** *ppBuf and *pNewMapSize might be NULL and zero if no space has
** yet been allocated to the underlying storage.
*/
static int unixShmGet(
  sqlite3_vfs *pVfs,       /* The VFS */
  sqlite3_shm *pSharedMem, /* Pointer returned by unixShmOpen() */
  int reqMapSize,          /* Requested size of mapping. -1 means don't care */
  int *pNewMapSize,        /* Write new size of mapping here */
  void **ppBuf             /* Write mapping buffer origin here */
){
  unixShm *p = (unixShm*)pSharedMem;
  unixShmFile *pFile = p->pFile;
  int rc = SQLITE_OK;

  if( p->lockState!=SQLITE_SHM_CHECKPOINT && p->hasMutexBuf==0 ){
    assert( sqlite3_mutex_notheld(pFile->mutex) );
    sqlite3_mutex_enter(pFile->mutexBuf);
    p->hasMutexBuf = 1;
  }
  sqlite3_mutex_enter(pFile->mutex);
  if( pFile->szMap==0 || reqMapSize>pFile->szMap ){
    int actualSize;
    if( unixShmSize(pVfs, pSharedMem, -1, &actualSize)==SQLITE_OK
     && reqMapSize<actualSize
    ){
      reqMapSize = actualSize;
    }
    if( pFile->pMMapBuf ){
      munmap(pFile->pMMapBuf, pFile->szMap);
    }
    pFile->pMMapBuf = mmap(0, reqMapSize, PROT_READ|PROT_WRITE, MAP_SHARED,
                           pFile->h, 0);
    pFile->szMap = pFile->pMMapBuf ? reqMapSize : 0;
  }
  *pNewMapSize = pFile->szMap;
  *ppBuf = pFile->pMMapBuf;
  sqlite3_mutex_leave(pFile->mutex);
  return rc;
}

/*
** Release the lock held on the shared memory segment to that other
** threads are free to resize it if necessary.
**
** If the lock is not currently held, this routine is a harmless no-op.
**
** If the shared-memory object is in lock state RECOVER, then we do not
** really want to release the lock, so in that case too, this routine
** is a no-op.
*/
static int unixShmRelease(sqlite3_vfs *pVfs, sqlite3_shm *pSharedMem){
  unixShm *p = (unixShm*)pSharedMem;
  UNUSED_PARAMETER(pVfs);
  if( p->hasMutexBuf && p->lockState!=SQLITE_SHM_RECOVER ){
    assert( sqlite3_mutex_notheld(p->pFile->mutex) );
    sqlite3_mutex_leave(p->pFile->mutexBuf);
    p->hasMutexBuf = 0;
  }
  return SQLITE_OK;
}

/*
** Symbolic names for LOCK states used for debugging.
*/
#ifdef SQLITE_DEBUG
static const char *azLkName[] = {
  "UNLOCK",
  "READ",
  "READ_FULL",
  "WRITE",
  "PENDING",
  "CHECKPOINT",
  "RECOVER"
};
#endif


/*
** Change the lock state for a shared-memory segment.
*/
static int unixShmLock(
  sqlite3_vfs *pVfs,         /* The VFS */
  sqlite3_shm *pSharedMem,   /* Pointer from unixShmOpen() */
  int desiredLock,           /* One of SQLITE_SHM_xxxxx locking states */
  int *pGotLock              /* The lock you actually got */
){
  unixShm *p = (unixShm*)pSharedMem;
  unixShmFile *pFile = p->pFile;
  int rc = SQLITE_PROTOCOL;

  UNUSED_PARAMETER(pVfs);

  /* Note that SQLITE_SHM_READ_FULL and SQLITE_SHM_PENDING are never
  ** directly requested; they are side effects from requesting
  ** SQLITE_SHM_READ and SQLITE_SHM_CHECKPOINT, respectively.
  */
  assert( desiredLock==SQLITE_SHM_UNLOCK
       || desiredLock==SQLITE_SHM_READ
       || desiredLock==SQLITE_SHM_WRITE
       || desiredLock==SQLITE_SHM_CHECKPOINT
       || desiredLock==SQLITE_SHM_RECOVER );

  /* Return directly if this is just a lock state query, or if
  ** the connection is already in the desired locking state.
  */
  if( desiredLock==p->lockState
   || (desiredLock==SQLITE_SHM_READ && p->lockState==SQLITE_SHM_READ_FULL)
  ){
    OSTRACE(("SHM-LOCK shmid-%d, pid-%d request %s and got %s\n",
             p->id, getpid(), azLkName[desiredLock], azLkName[p->lockState]));
    if( pGotLock ) *pGotLock = p->lockState;
    return SQLITE_OK;
  }

  OSTRACE(("SHM-LOCK shmid-%d, pid-%d request %s->%s\n",
            p->id, getpid(), azLkName[p->lockState], azLkName[desiredLock]));
  
  if( desiredLock==SQLITE_SHM_RECOVER && !p->hasMutexBuf ){
    assert( sqlite3_mutex_notheld(pFile->mutex) );
    sqlite3_mutex_enter(pFile->mutexBuf);
    p->hasMutexBuf = 1;
  }
  sqlite3_mutex_enter(pFile->mutex);
  switch( desiredLock ){
    case SQLITE_SHM_UNLOCK: {
      assert( p->lockState!=SQLITE_SHM_RECOVER );
      unixShmUnlock(pFile, p, UNIX_SHM_A|UNIX_SHM_B|UNIX_SHM_C|UNIX_SHM_D);
      rc = SQLITE_OK;
      p->lockState = SQLITE_SHM_UNLOCK;
      break;
    }
    case SQLITE_SHM_READ: {
      if( p->lockState==SQLITE_SHM_UNLOCK ){
        int nAttempt;
        rc = SQLITE_BUSY;
        assert( p->lockState==SQLITE_SHM_UNLOCK );
        for(nAttempt=0; nAttempt<5 && rc==SQLITE_BUSY; nAttempt++){
          rc = unixShmSharedLock(pFile, p, UNIX_SHM_A|UNIX_SHM_B);
          if( rc==SQLITE_BUSY ){
            rc = unixShmSharedLock(pFile, p, UNIX_SHM_D);
            if( rc==SQLITE_OK ){
              p->lockState = SQLITE_SHM_READ_FULL;
            }
          }else{
            unixShmUnlock(pFile, p, UNIX_SHM_B);
            p->lockState = SQLITE_SHM_READ;
          }
        }
      }else{
       assert( p->lockState==SQLITE_SHM_WRITE
               || p->lockState==SQLITE_SHM_RECOVER );
        rc = unixShmSharedLock(pFile, p, UNIX_SHM_A);
        unixShmUnlock(pFile, p, UNIX_SHM_C|UNIX_SHM_D);
        p->lockState = SQLITE_SHM_READ;
      }
      break;
    }
    case SQLITE_SHM_WRITE: {
      assert( p->lockState==SQLITE_SHM_READ 
              || p->lockState==SQLITE_SHM_READ_FULL );
      rc = unixShmExclusiveLock(pFile, p, UNIX_SHM_C|UNIX_SHM_D);
      if( rc==SQLITE_OK ){
        p->lockState = SQLITE_SHM_WRITE;
      }
      break;
    }
    case SQLITE_SHM_CHECKPOINT: {
      assert( p->lockState==SQLITE_SHM_UNLOCK
           || p->lockState==SQLITE_SHM_PENDING
      );
      if( p->lockState==SQLITE_SHM_UNLOCK ){
        rc = unixShmExclusiveLock(pFile, p, UNIX_SHM_B|UNIX_SHM_C);
        if( rc==SQLITE_OK ){
          p->lockState = SQLITE_SHM_PENDING;
        }
      }
      if( p->lockState==SQLITE_SHM_PENDING ){
        rc = unixShmExclusiveLock(pFile, p, UNIX_SHM_A);
        if( rc==SQLITE_OK ){
          p->lockState = SQLITE_SHM_CHECKPOINT;
        }
      }
      break;
    }
    default: {
      assert( desiredLock==SQLITE_SHM_RECOVER );
      assert( p->lockState==SQLITE_SHM_READ
           || p->lockState==SQLITE_SHM_READ_FULL
      );
      assert( sqlite3_mutex_held(pFile->mutexBuf) );
      rc = unixShmExclusiveLock(pFile, p, UNIX_SHM_C);
      if( rc==SQLITE_OK ){
        p->lockState = SQLITE_SHM_RECOVER;
      }
      break;
    }
  }
  sqlite3_mutex_leave(pFile->mutex);
  OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %s\n",
           p->id, getpid(), azLkName[p->lockState]));
  if( pGotLock ) *pGotLock = p->lockState;
  return rc;
}

#else
# define unixShmOpen    0
# define unixShmSize    0
# define unixShmGet     0
# define unixShmRelease 0
# define unixShmLock    0
# define unixShmClose   0
#endif /* #ifndef SQLITE_OMIT_WAL */

/*
************************ End of sqlite3_vfs methods ***************************
******************************************************************************/

/******************************************************************************
************************** Begin Proxy Locking ********************************







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<
<
<
<
<
<
<
<
<







5071
5072
5073
5074
5075
5076
5077






































































































































































































































































































































































































































































































































































































































































































































































































































5078
5079
5080
5081
5082
5083
5084
static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
  UNUSED_PARAMETER(NotUsed);
  UNUSED_PARAMETER(NotUsed2);
  UNUSED_PARAMETER(NotUsed3);
  return 0;
}








































































































































































































































































































































































































































































































































































































































































































































































































































/*
************************ End of sqlite3_vfs methods ***************************
******************************************************************************/

/******************************************************************************
************************** Begin Proxy Locking ********************************
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583

#ifdef LOCKPROXYDIR
  len = strlcpy(lPath, LOCKPROXYDIR, maxLen);
#else
# ifdef _CS_DARWIN_USER_TEMP_DIR
  {
    if( !confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen) ){
      OSTRACE4("GETLOCKPATH  failed %s errno=%d pid=%d\n",
               lPath, errno, getpid());
      return SQLITE_IOERR_LOCK;
    }
    len = strlcat(lPath, "sqliteplocks", maxLen);    
  }
# else
  len = strlcpy(lPath, "/tmp/", maxLen);
# endif







|
|







5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277

#ifdef LOCKPROXYDIR
  len = strlcpy(lPath, LOCKPROXYDIR, maxLen);
#else
# ifdef _CS_DARWIN_USER_TEMP_DIR
  {
    if( !confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen) ){
      OSTRACE(("GETLOCKPATH  failed %s errno=%d pid=%d\n",
               lPath, errno, getpid()));
      return SQLITE_IOERR_LOCK;
    }
    len = strlcat(lPath, "sqliteplocks", maxLen);    
  }
# else
  len = strlcpy(lPath, "/tmp/", maxLen);
# endif
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
  dbLen = (int)strlen(dbPath);
  for( i=0; i<dbLen && (i+len+7)<maxLen; i++){
    char c = dbPath[i];
    lPath[i+len] = (c=='/')?'_':c;
  }
  lPath[i+len]='\0';
  strlcat(lPath, ":auto:", maxLen);
  OSTRACE3("GETLOCKPATH  proxy lock path=%s pid=%d\n", lPath, getpid());
  return SQLITE_OK;
}

/* 
 ** Creates the lock file and any missing directories in lockPath
 */
static int proxyCreateLockPath(const char *lockPath){







|







5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
  dbLen = (int)strlen(dbPath);
  for( i=0; i<dbLen && (i+len+7)<maxLen; i++){
    char c = dbPath[i];
    lPath[i+len] = (c=='/')?'_':c;
  }
  lPath[i+len]='\0';
  strlcat(lPath, ":auto:", maxLen);
  OSTRACE(("GETLOCKPATH  proxy lock path=%s pid=%d\n", lPath, getpid()));
  return SQLITE_OK;
}

/* 
 ** Creates the lock file and any missing directories in lockPath
 */
static int proxyCreateLockPath(const char *lockPath){
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
      /* only mkdir if leaf dir != "." or "/" or ".." */
      if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/') 
         || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){
        buf[i]='\0';
        if( mkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
          int err=errno;
          if( err!=EEXIST ) {
            OSTRACE5("CREATELOCKPATH  FAILED creating %s, "
                     "'%s' proxy lock path=%s pid=%d\n",
                     buf, strerror(err), lockPath, getpid());
            return err;
          }
        }
      }
      start=i+1;
    }
    buf[i] = lockPath[i];
  }
  OSTRACE3("CREATELOCKPATH  proxy lock path=%s pid=%d\n", lockPath, getpid());
  return 0;
}

/*
** Create a new VFS file descriptor (stored in memory obtained from
** sqlite3_malloc) and open the file named "path" in the file descriptor.
**







|

|








|







5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
      /* only mkdir if leaf dir != "." or "/" or ".." */
      if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/') 
         || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){
        buf[i]='\0';
        if( mkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
          int err=errno;
          if( err!=EEXIST ) {
            OSTRACE(("CREATELOCKPATH  FAILED creating %s, "
                     "'%s' proxy lock path=%s pid=%d\n",
                     buf, strerror(err), lockPath, getpid()));
            return err;
          }
        }
      }
      start=i+1;
    }
    buf[i] = lockPath[i];
  }
  OSTRACE(("CREATELOCKPATH  proxy lock path=%s pid=%d\n", lockPath, getpid()));
  return 0;
}

/*
** Create a new VFS file descriptor (stored in memory obtained from
** sqlite3_malloc) and open the file named "path" in the file descriptor.
**
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
    int rc = SQLITE_OK;
    int createConch = 0;
    int hostIdMatch = 0;
    int readLen = 0;
    int tryOldLockPath = 0;
    int forceNewLockPath = 0;
    
    OSTRACE4("TAKECONCH  %d for %s pid=%d\n", conchFile->h,
             (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), getpid());

    rc = proxyGetHostID(myHostID, &pError);
    if( (rc&0xff)==SQLITE_IOERR ){
      pFile->lastErrno = pError;
      goto end_takeconch;
    }
    rc = proxyConchLock(pFile, myHostID, SHARED_LOCK);







|
|







5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
    int rc = SQLITE_OK;
    int createConch = 0;
    int hostIdMatch = 0;
    int readLen = 0;
    int tryOldLockPath = 0;
    int forceNewLockPath = 0;
    
    OSTRACE(("TAKECONCH  %d for %s pid=%d\n", conchFile->h,
             (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), getpid()));

    rc = proxyGetHostID(myHostID, &pError);
    if( (rc&0xff)==SQLITE_IOERR ){
      pFile->lastErrno = pError;
      goto end_takeconch;
    }
    rc = proxyConchLock(pFile, myHostID, SHARED_LOCK);
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
      
      /* update conch with host and path (this will fail if other process
      ** has a shared lock already), if the host id matches, use the big
      ** stick.
      */
      futimes(conchFile->h, NULL);
      if( hostIdMatch && !createConch ){
        if( conchFile->pLock && conchFile->pLock->cnt>1 ){
          /* We are trying for an exclusive lock but another thread in this
           ** same process is still holding a shared lock. */
          rc = SQLITE_BUSY;
        } else {          
          rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK);
        }
      }else{







|







5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
      
      /* update conch with host and path (this will fail if other process
      ** has a shared lock already), if the host id matches, use the big
      ** stick.
      */
      futimes(conchFile->h, NULL);
      if( hostIdMatch && !createConch ){
        if( conchFile->pInode && conchFile->pInode->nShared>1 ){
          /* We are trying for an exclusive lock but another thread in this
           ** same process is still holding a shared lock. */
          rc = SQLITE_BUSY;
        } else {          
          rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK);
        }
      }else{
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
#endif
          }
        }
      }
      conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK);
      
    end_takeconch:
      OSTRACE2("TRANSPROXY: CLOSE  %d\n", pFile->h);
      if( rc==SQLITE_OK && pFile->openFlags ){
        if( pFile->h>=0 ){
#ifdef STRICT_CLOSE_ERROR
          if( close(pFile->h) ){
            pFile->lastErrno = errno;
            return SQLITE_IOERR_CLOSE;
          }
#else
          close(pFile->h); /* silently leak fd if fail */
#endif
        }
        pFile->h = -1;
        int fd = open(pCtx->dbPath, pFile->openFlags,
                      SQLITE_DEFAULT_FILE_PERMISSIONS);
        OSTRACE2("TRANSPROXY: OPEN  %d\n", fd);
        if( fd>=0 ){
          pFile->h = fd;
        }else{
          rc=SQLITE_CANTOPEN_BKPT; /* SQLITE_BUSY? proxyTakeConch called
           during locking */
        }
      }







|














|







5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
#endif
          }
        }
      }
      conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK);
      
    end_takeconch:
      OSTRACE(("TRANSPROXY: CLOSE  %d\n", pFile->h));
      if( rc==SQLITE_OK && pFile->openFlags ){
        if( pFile->h>=0 ){
#ifdef STRICT_CLOSE_ERROR
          if( close(pFile->h) ){
            pFile->lastErrno = errno;
            return SQLITE_IOERR_CLOSE;
          }
#else
          close(pFile->h); /* silently leak fd if fail */
#endif
        }
        pFile->h = -1;
        int fd = open(pCtx->dbPath, pFile->openFlags,
                      SQLITE_DEFAULT_FILE_PERMISSIONS);
        OSTRACE(("TRANSPROXY: OPEN  %d\n", fd));
        if( fd>=0 ){
          pFile->h = fd;
        }else{
          rc=SQLITE_CANTOPEN_BKPT; /* SQLITE_BUSY? proxyTakeConch called
           during locking */
        }
      }
6113
6114
6115
6116
6117
6118
6119
6120

6121
6122

6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
          afpLockingContext *afpCtx;
          afpCtx = (afpLockingContext *)pCtx->lockProxy->lockingContext;
          afpCtx->dbPath = pCtx->lockProxyPath;
        }
      } else {
        conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
      }
      OSTRACE3("TAKECONCH  %d %s\n", conchFile->h, rc==SQLITE_OK?"ok":"failed");

      return rc;
    } while (1); /* in case we need to retry the :auto: lock file - we should never get here except via the 'continue' call. */

  }
}

/*
** If pFile holds a lock on a conch file, then release that lock.
*/
static int proxyReleaseConch(unixFile *pFile){
  int rc = SQLITE_OK;         /* Subroutine return code */
  proxyLockingContext *pCtx;  /* The locking context for the proxy lock */
  unixFile *conchFile;        /* Name of the conch file */

  pCtx = (proxyLockingContext *)pFile->lockingContext;
  conchFile = pCtx->conchFile;
  OSTRACE4("RELEASECONCH  %d for %s pid=%d\n", conchFile->h,
           (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), 
           getpid());
  if( pCtx->conchHeld>0 ){
    rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
  }
  pCtx->conchHeld = 0;
  OSTRACE3("RELEASECONCH  %d %s\n", conchFile->h,
           (rc==SQLITE_OK ? "ok" : "failed"));
  return rc;
}

/*
** Given the name of a database file, compute the name of its conch file.
** Store the conch filename in memory obtained from sqlite3_malloc().
** Make *pConchPath point to the new name.  Return SQLITE_OK on success







|
>

|
>













|

|




|
|







5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
          afpLockingContext *afpCtx;
          afpCtx = (afpLockingContext *)pCtx->lockProxy->lockingContext;
          afpCtx->dbPath = pCtx->lockProxyPath;
        }
      } else {
        conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
      }
      OSTRACE(("TAKECONCH  %d %s\n", conchFile->h,
               rc==SQLITE_OK?"ok":"failed"));
      return rc;
    } while (1); /* in case we need to retry the :auto: lock file - 
                 ** we should never get here except via the 'continue' call. */
  }
}

/*
** If pFile holds a lock on a conch file, then release that lock.
*/
static int proxyReleaseConch(unixFile *pFile){
  int rc = SQLITE_OK;         /* Subroutine return code */
  proxyLockingContext *pCtx;  /* The locking context for the proxy lock */
  unixFile *conchFile;        /* Name of the conch file */

  pCtx = (proxyLockingContext *)pFile->lockingContext;
  conchFile = pCtx->conchFile;
  OSTRACE(("RELEASECONCH  %d for %s pid=%d\n", conchFile->h,
           (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), 
           getpid()));
  if( pCtx->conchHeld>0 ){
    rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
  }
  pCtx->conchHeld = 0;
  OSTRACE(("RELEASECONCH  %d %s\n", conchFile->h,
           (rc==SQLITE_OK ? "ok" : "failed")));
  return rc;
}

/*
** Given the name of a database file, compute the name of its conch file.
** Store the conch filename in memory obtained from sqlite3_malloc().
** Make *pConchPath point to the new name.  Return SQLITE_OK on success
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
** the local lock file path 
*/
static int switchLockProxyPath(unixFile *pFile, const char *path) {
  proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext;
  char *oldPath = pCtx->lockProxyPath;
  int rc = SQLITE_OK;

  if( pFile->locktype!=NO_LOCK ){
    return SQLITE_BUSY;
  }  

  /* nothing to do if the path is NULL, :auto: or matches the existing path */
  if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ||
    (oldPath && !strncmp(oldPath, path, MAXPATHLEN)) ){
    return SQLITE_OK;







|







5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
** the local lock file path 
*/
static int switchLockProxyPath(unixFile *pFile, const char *path) {
  proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext;
  char *oldPath = pCtx->lockProxyPath;
  int rc = SQLITE_OK;

  if( pFile->eFileLock!=NO_LOCK ){
    return SQLITE_BUSY;
  }  

  /* nothing to do if the path is NULL, :auto: or matches the existing path */
  if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ||
    (oldPath && !strncmp(oldPath, path, MAXPATHLEN)) ){
    return SQLITE_OK;
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
*/
static int proxyTransformUnixFile(unixFile *pFile, const char *path) {
  proxyLockingContext *pCtx;
  char dbPath[MAXPATHLEN+1];       /* Name of the database file */
  char *lockPath=NULL;
  int rc = SQLITE_OK;
  
  if( pFile->locktype!=NO_LOCK ){
    return SQLITE_BUSY;
  }
  proxyGetDbPathForUnixFile(pFile, dbPath);
  if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ){
    lockPath=NULL;
  }else{
    lockPath=(char *)path;
  }
  
  OSTRACE4("TRANSPROXY  %d for %s pid=%d\n", pFile->h,
           (lockPath ? lockPath : ":auto:"), getpid());

  pCtx = sqlite3_malloc( sizeof(*pCtx) );
  if( pCtx==0 ){
    return SQLITE_NOMEM;
  }
  memset(pCtx, 0, sizeof(*pCtx));








|









|
|







5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
*/
static int proxyTransformUnixFile(unixFile *pFile, const char *path) {
  proxyLockingContext *pCtx;
  char dbPath[MAXPATHLEN+1];       /* Name of the database file */
  char *lockPath=NULL;
  int rc = SQLITE_OK;
  
  if( pFile->eFileLock!=NO_LOCK ){
    return SQLITE_BUSY;
  }
  proxyGetDbPathForUnixFile(pFile, dbPath);
  if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ){
    lockPath=NULL;
  }else{
    lockPath=(char *)path;
  }
  
  OSTRACE(("TRANSPROXY  %d for %s pid=%d\n", pFile->h,
           (lockPath ? lockPath : ":auto:"), getpid()));

  pCtx = sqlite3_malloc( sizeof(*pCtx) );
  if( pCtx==0 ){
    return SQLITE_NOMEM;
  }
  memset(pCtx, 0, sizeof(*pCtx));

6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
      pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile);
      sqlite3_free(pCtx->conchFile);
    }
    sqlite3_free(pCtx->lockProxyPath);
    sqlite3_free(pCtx->conchFilePath); 
    sqlite3_free(pCtx);
  }
  OSTRACE3("TRANSPROXY  %d %s\n", pFile->h,
           (rc==SQLITE_OK ? "ok" : "failed"));
  return rc;
}


/*
** This routine handles sqlite3_file_control() calls that are specific
** to proxy locking.







|
|







6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
      pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile);
      sqlite3_free(pCtx->conchFile);
    }
    sqlite3_free(pCtx->lockProxyPath);
    sqlite3_free(pCtx->conchFilePath); 
    sqlite3_free(pCtx);
  }
  OSTRACE(("TRANSPROXY  %d %s\n", pFile->h,
           (rc==SQLITE_OK ? "ok" : "failed")));
  return rc;
}


/*
** This routine handles sqlite3_file_control() calls that are specific
** to proxy locking.
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
      pResOut=0;
    }
  }
  return rc;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**







|







6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
      pResOut=0;
    }
  }
  return rc;
}

/*
** Lock the file with the lock specified by parameter eFileLock - one
** of the following:
**
**     (1) SHARED_LOCK
**     (2) RESERVED_LOCK
**     (3) PENDING_LOCK
**     (4) EXCLUSIVE_LOCK
**
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
**    SHARED -> (PENDING) -> EXCLUSIVE
**    RESERVED -> (PENDING) -> EXCLUSIVE
**    PENDING -> EXCLUSIVE
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int proxyLock(sqlite3_file *id, int locktype) {
  unixFile *pFile = (unixFile*)id;
  int rc = proxyTakeConch(pFile);
  if( rc==SQLITE_OK ){
    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
    if( pCtx->conchHeld>0 ){
      unixFile *proxy = pCtx->lockProxy;
      rc = proxy->pMethod->xLock((sqlite3_file*)proxy, locktype);
      pFile->locktype = proxy->locktype;
    }else{
      /* conchHeld < 0 is lockless */
    }
  }
  return rc;
}


/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int proxyUnlock(sqlite3_file *id, int locktype) {
  unixFile *pFile = (unixFile*)id;
  int rc = proxyTakeConch(pFile);
  if( rc==SQLITE_OK ){
    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
    if( pCtx->conchHeld>0 ){
      unixFile *proxy = pCtx->lockProxy;
      rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, locktype);
      pFile->locktype = proxy->locktype;
    }else{
      /* conchHeld < 0 is lockless */
    }
  }
  return rc;
}








|






|
|









|





|






|
|







6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
**    SHARED -> (PENDING) -> EXCLUSIVE
**    RESERVED -> (PENDING) -> EXCLUSIVE
**    PENDING -> EXCLUSIVE
**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int proxyLock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  int rc = proxyTakeConch(pFile);
  if( rc==SQLITE_OK ){
    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
    if( pCtx->conchHeld>0 ){
      unixFile *proxy = pCtx->lockProxy;
      rc = proxy->pMethod->xLock((sqlite3_file*)proxy, eFileLock);
      pFile->eFileLock = proxy->eFileLock;
    }else{
      /* conchHeld < 0 is lockless */
    }
  }
  return rc;
}


/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int proxyUnlock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  int rc = proxyTakeConch(pFile);
  if( rc==SQLITE_OK ){
    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
    if( pCtx->conchHeld>0 ){
      unixFile *proxy = pCtx->lockProxy;
      rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, eFileLock);
      pFile->eFileLock = proxy->eFileLock;
    }else{
      /* conchHeld < 0 is lockless */
    }
  }
  return rc;
}

6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
    unixDlError,          /* xDlError */                    \
    unixDlSym,            /* xDlSym */                      \
    unixDlClose,          /* xDlClose */                    \
    unixRandomness,       /* xRandomness */                 \
    unixSleep,            /* xSleep */                      \
    unixCurrentTime,      /* xCurrentTime */                \
    unixGetLastError,     /* xGetLastError */               \
    unixShmOpen,          /* xShmOpen */                    \
    unixShmSize,          /* xShmSize */                    \
    unixShmGet,           /* xShmGet */                     \
    unixShmRelease,       /* xShmRelease */                 \
    unixShmLock,          /* xShmLock */                    \
    unixShmClose,         /* xShmClose */                   \
    0,                    /* xRename */                     \
    unixCurrentTimeInt64, /* xCurrentTimeInt64 */           \
  }

  /*
  ** All default VFSes for unix are contained in the following array.
  **







<
<
<
<
<
<







6292
6293
6294
6295
6296
6297
6298






6299
6300
6301
6302
6303
6304
6305
    unixDlError,          /* xDlError */                    \
    unixDlSym,            /* xDlSym */                      \
    unixDlClose,          /* xDlClose */                    \
    unixRandomness,       /* xRandomness */                 \
    unixSleep,            /* xSleep */                      \
    unixCurrentTime,      /* xCurrentTime */                \
    unixGetLastError,     /* xGetLastError */               \






    0,                    /* xRename */                     \
    unixCurrentTimeInt64, /* xCurrentTimeInt64 */           \
  }

  /*
  ** All default VFSes for unix are contained in the following array.
  **
Changes to src/os_win.c.
72
73
74
75
76
77
78




79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98

99
100
101
102
103


104
105
106
107
108
109
110
** reduced API.
*/
#if SQLITE_OS_WINCE
# define AreFileApisANSI() 1
# define FormatMessageW(a,b,c,d,e,f,g) 0
#endif





/*
** WinCE lacks native support for file locking so we have to fake it
** with some code of our own.
*/
#if SQLITE_OS_WINCE
typedef struct winceLock {
  int nReaders;       /* Number of reader locks obtained */
  BOOL bPending;      /* Indicates a pending lock has been obtained */
  BOOL bReserved;     /* Indicates a reserved lock has been obtained */
  BOOL bExclusive;    /* Indicates an exclusive lock has been obtained */
} winceLock;
#endif

/*
** The winFile structure is a subclass of sqlite3_file* specific to the win32
** portability layer.
*/
typedef struct winFile winFile;
struct winFile {
  const sqlite3_io_methods *pMethod;/* Must be first */

  HANDLE h;               /* Handle for accessing the file */
  unsigned char locktype; /* Type of lock currently held on this file */
  short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
  DWORD lastErrno;        /* The Windows errno from the last I/O error */
  DWORD sectorSize;       /* Sector size of the device file is on */


#if SQLITE_OS_WINCE
  WCHAR *zDeleteOnClose;  /* Name of file to delete when closing */
  HANDLE hMutex;          /* Mutex used to control access to shared lock */  
  HANDLE hShared;         /* Shared memory segment used for locking */
  winceLock local;        /* Locks obtained by this instance of winFile */
  winceLock *shared;      /* Global shared lock memory for the file  */
#endif







>
>
>
>



















|
>





>
>







72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
** reduced API.
*/
#if SQLITE_OS_WINCE
# define AreFileApisANSI() 1
# define FormatMessageW(a,b,c,d,e,f,g) 0
#endif

/* Forward references */
typedef struct winShm winShm;           /* A connection to shared-memory */
typedef struct winShmNode winShmNode;   /* A region of shared-memory */

/*
** WinCE lacks native support for file locking so we have to fake it
** with some code of our own.
*/
#if SQLITE_OS_WINCE
typedef struct winceLock {
  int nReaders;       /* Number of reader locks obtained */
  BOOL bPending;      /* Indicates a pending lock has been obtained */
  BOOL bReserved;     /* Indicates a reserved lock has been obtained */
  BOOL bExclusive;    /* Indicates an exclusive lock has been obtained */
} winceLock;
#endif

/*
** The winFile structure is a subclass of sqlite3_file* specific to the win32
** portability layer.
*/
typedef struct winFile winFile;
struct winFile {
  const sqlite3_io_methods *pMethod; /*** Must be first ***/
  sqlite3_vfs *pVfs;      /* The VFS used to open this file */
  HANDLE h;               /* Handle for accessing the file */
  unsigned char locktype; /* Type of lock currently held on this file */
  short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
  DWORD lastErrno;        /* The Windows errno from the last I/O error */
  DWORD sectorSize;       /* Sector size of the device file is on */
  winShm *pShm;           /* Instance of shared memory on this file */
  const char *zPath;      /* Full pathname of this file */
#if SQLITE_OS_WINCE
  WCHAR *zDeleteOnClose;  /* Name of file to delete when closing */
  HANDLE hMutex;          /* Mutex used to control access to shared lock */  
  HANDLE hShared;         /* Shared memory segment used for locking */
  winceLock local;        /* Locks obtained by this instance of winFile */
  winceLock *shared;      /* Global shared lock memory for the file  */
#endif
625
626
627
628
629
630
631


632
633
634
635
636
637
638
*/
#define MX_CLOSE_ATTEMPT 3
static int winClose(sqlite3_file *id){
  int rc, cnt = 0;
  winFile *pFile = (winFile*)id;

  assert( id!=0 );


  do{
    rc = CloseHandle(pFile->h);
  }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (Sleep(100), 1) );
#if SQLITE_OS_WINCE
#define WINCE_DELETION_ATTEMPTS 3
  winceDestroyLock(pFile);
  if( pFile->zDeleteOnClose ){







>
>







632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
*/
#define MX_CLOSE_ATTEMPT 3
static int winClose(sqlite3_file *id){
  int rc, cnt = 0;
  winFile *pFile = (winFile*)id;

  assert( id!=0 );
  assert( pFile->pShm==0 );
  OSTRACE(("CLOSE %d\n", pFile->h));
  do{
    rc = CloseHandle(pFile->h);
  }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (Sleep(100), 1) );
#if SQLITE_OS_WINCE
#define WINCE_DELETION_ATTEMPTS 3
  winceDestroyLock(pFile);
  if( pFile->zDeleteOnClose ){
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
  DWORD rc;
  winFile *pFile = (winFile*)id;
  DWORD error;
  DWORD got;

  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_READ);
  OSTRACE3("READ %d lock=%d\n", pFile->h, pFile->locktype);
  rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
  if( rc==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
    pFile->lastErrno = error;
    return SQLITE_FULL;
  }
  if( !ReadFile(pFile->h, pBuf, amt, &got, 0) ){
    pFile->lastErrno = GetLastError();







|







684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
  DWORD rc;
  winFile *pFile = (winFile*)id;
  DWORD error;
  DWORD got;

  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_READ);
  OSTRACE(("READ %d lock=%d\n", pFile->h, pFile->locktype));
  rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
  if( rc==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
    pFile->lastErrno = error;
    return SQLITE_FULL;
  }
  if( !ReadFile(pFile->h, pBuf, amt, &got, 0) ){
    pFile->lastErrno = GetLastError();
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
  winFile *pFile = (winFile*)id;
  DWORD error;
  DWORD wrote = 0;

  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_WRITE);
  SimulateDiskfullError(return SQLITE_FULL);
  OSTRACE3("WRITE %d lock=%d\n", pFile->h, pFile->locktype);
  rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
  if( rc==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
    pFile->lastErrno = error;
    return SQLITE_FULL;
  }
  assert( amt>0 );
  while(







|







723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
  winFile *pFile = (winFile*)id;
  DWORD error;
  DWORD wrote = 0;

  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_WRITE);
  SimulateDiskfullError(return SQLITE_FULL);
  OSTRACE(("WRITE %d lock=%d\n", pFile->h, pFile->locktype));
  rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
  if( rc==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
    pFile->lastErrno = error;
    return SQLITE_FULL;
  }
  assert( amt>0 );
  while(
748
749
750
751
752
753
754

755
756
757
758
759
760
761
  LONG lowerBits = (LONG)(nByte & 0xffffffff);
  DWORD dwRet;
  winFile *pFile = (winFile*)id;
  DWORD error;
  int rc = SQLITE_OK;

  assert( id!=0 );

  SimulateIOError(return SQLITE_IOERR_TRUNCATE);
  dwRet = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
  if( dwRet==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
    pFile->lastErrno = error;
    rc = SQLITE_IOERR_TRUNCATE;
  /* SetEndOfFile will fail if nByte is negative */
  }else if( !SetEndOfFile(pFile->h) ){







>







757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
  LONG lowerBits = (LONG)(nByte & 0xffffffff);
  DWORD dwRet;
  winFile *pFile = (winFile*)id;
  DWORD error;
  int rc = SQLITE_OK;

  assert( id!=0 );
  OSTRACE(("TRUNCATE %d %lld\n", pFile->h, nByte));
  SimulateIOError(return SQLITE_IOERR_TRUNCATE);
  dwRet = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
  if( dwRet==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
    pFile->lastErrno = error;
    rc = SQLITE_IOERR_TRUNCATE;
  /* SetEndOfFile will fail if nByte is negative */
  }else if( !SetEndOfFile(pFile->h) ){
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
** Make sure all writes to a particular file are committed to disk.
*/
static int winSync(sqlite3_file *id, int flags){
#ifndef SQLITE_NO_SYNC
  winFile *pFile = (winFile*)id;

  assert( id!=0 );
  OSTRACE3("SYNC %d lock=%d\n", pFile->h, pFile->locktype);
#else
  UNUSED_PARAMETER(id);
#endif
#ifndef SQLITE_TEST
  UNUSED_PARAMETER(flags);
#else
  if( flags & SQLITE_SYNC_FULL ){







|







789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
** Make sure all writes to a particular file are committed to disk.
*/
static int winSync(sqlite3_file *id, int flags){
#ifndef SQLITE_NO_SYNC
  winFile *pFile = (winFile*)id;

  assert( id!=0 );
  OSTRACE(("SYNC %d lock=%d\n", pFile->h, pFile->locktype));
#else
  UNUSED_PARAMETER(id);
#endif
#ifndef SQLITE_TEST
  UNUSED_PARAMETER(flags);
#else
  if( flags & SQLITE_SYNC_FULL ){
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
         && (pFile->locktype==RESERVED_LOCK))
  ){
    int cnt = 3;
    while( cnt-->0 && (res = LockFile(pFile->h, PENDING_BYTE, 0, 1, 0))==0 ){
      /* Try 3 times to get the pending lock.  The pending lock might be
      ** held by another reader process who will release it momentarily.
      */
      OSTRACE2("could not get a PENDING lock. cnt=%d\n", cnt);
      Sleep(1);
    }
    gotPendingLock = res;
    if( !res ){
      error = GetLastError();
    }
  }







|







961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
         && (pFile->locktype==RESERVED_LOCK))
  ){
    int cnt = 3;
    while( cnt-->0 && (res = LockFile(pFile->h, PENDING_BYTE, 0, 1, 0))==0 ){
      /* Try 3 times to get the pending lock.  The pending lock might be
      ** held by another reader process who will release it momentarily.
      */
      OSTRACE(("could not get a PENDING lock. cnt=%d\n", cnt));
      Sleep(1);
    }
    gotPendingLock = res;
    if( !res ){
      error = GetLastError();
    }
  }
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    assert( pFile->locktype>=SHARED_LOCK );
    res = unlockReadLock(pFile);
    OSTRACE2("unreadlock = %d\n", res);
    res = LockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( res ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      error = GetLastError();
      OSTRACE2("error-code = %d\n", error);
      getReadLock(pFile);
    }
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){
    UnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res ){
    rc = SQLITE_OK;
  }else{
    OSTRACE4("LOCK FAILED %d trying for %d but got %d\n", pFile->h,
           locktype, newLocktype);
    pFile->lastErrno = error;
    rc = SQLITE_BUSY;
  }
  pFile->locktype = (u8)newLocktype;
  return rc;
}

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, return
** non-zero, otherwise zero.
*/
static int winCheckReservedLock(sqlite3_file *id, int *pResOut){
  int rc;
  winFile *pFile = (winFile*)id;

  assert( id!=0 );
  if( pFile->locktype>=RESERVED_LOCK ){
    rc = 1;
    OSTRACE3("TEST WR-LOCK %d %d (local)\n", pFile->h, rc);
  }else{
    rc = LockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    if( rc ){
      UnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    }
    rc = !rc;
    OSTRACE3("TEST WR-LOCK %d %d (remote)\n", pFile->h, rc);
  }
  *pResOut = rc;
  return SQLITE_OK;
}

/*
** Lower the locking level on file descriptor id to locktype.  locktype







|





|

















|
|



















|






|







1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    assert( pFile->locktype>=SHARED_LOCK );
    res = unlockReadLock(pFile);
    OSTRACE(("unreadlock = %d\n", res));
    res = LockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( res ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      error = GetLastError();
      OSTRACE(("error-code = %d\n", error));
      getReadLock(pFile);
    }
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){
    UnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res ){
    rc = SQLITE_OK;
  }else{
    OSTRACE(("LOCK FAILED %d trying for %d but got %d\n", pFile->h,
           locktype, newLocktype));
    pFile->lastErrno = error;
    rc = SQLITE_BUSY;
  }
  pFile->locktype = (u8)newLocktype;
  return rc;
}

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, return
** non-zero, otherwise zero.
*/
static int winCheckReservedLock(sqlite3_file *id, int *pResOut){
  int rc;
  winFile *pFile = (winFile*)id;

  assert( id!=0 );
  if( pFile->locktype>=RESERVED_LOCK ){
    rc = 1;
    OSTRACE(("TEST WR-LOCK %d %d (local)\n", pFile->h, rc));
  }else{
    rc = LockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    if( rc ){
      UnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    }
    rc = !rc;
    OSTRACE(("TEST WR-LOCK %d %d (remote)\n", pFile->h, rc));
  }
  *pResOut = rc;
  return SQLITE_OK;
}

/*
** Lower the locking level on file descriptor id to locktype.  locktype
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
*/
static int winUnlock(sqlite3_file *id, int locktype){
  int type;
  winFile *pFile = (winFile*)id;
  int rc = SQLITE_OK;
  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE5("UNLOCK %d to %d was %d(%d)\n", pFile->h, locktype,
          pFile->locktype, pFile->sharedLockByte);
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    UnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( locktype==SHARED_LOCK && !getReadLock(pFile) ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */
      rc = SQLITE_IOERR_UNLOCK;







|
|







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*/
static int winUnlock(sqlite3_file *id, int locktype){
  int type;
  winFile *pFile = (winFile*)id;
  int rc = SQLITE_OK;
  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE(("UNLOCK %d to %d was %d(%d)\n", pFile->h, locktype,
          pFile->locktype, pFile->sharedLockByte));
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    UnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( locktype==SHARED_LOCK && !getReadLock(pFile) ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */
      rc = SQLITE_IOERR_UNLOCK;
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** Return a vector of device characteristics.
*/
static int winDeviceCharacteristics(sqlite3_file *id){
  UNUSED_PARAMETER(id);
  return 0;
}









































































































































































































































































































































































































































































































































































































































































































































































































































































































































































/*
** This vector defines all the methods that can operate on an
** sqlite3_file for win32.
*/
static const sqlite3_io_methods winIoMethod = {
  1,                        /* iVersion */
  winClose,
  winRead,
  winWrite,
  winTruncate,
  winSync,
  winFileSize,
  winLock,
  winUnlock,
  winCheckReservedLock,
  winFileControl,
  winSectorSize,
  winDeviceCharacteristics






};

/***************************************************************************
** Here ends the I/O methods that form the sqlite3_io_methods object.
**
** The next block of code implements the VFS methods.
****************************************************************************/







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|











|
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** Return a vector of device characteristics.
*/
static int winDeviceCharacteristics(sqlite3_file *id){
  UNUSED_PARAMETER(id);
  return 0;
}

/****************************************************************************
********************************* Shared Memory *****************************
**
** The next subdivision of code manages the shared-memory primitives.
*/
#ifndef SQLITE_OMIT_WAL

/*
** Helper functions to obtain and relinquish the global mutex. The
** global mutex is used to protect the winLockInfo objects used by 
** this file, all of which may be shared by multiple threads.
**
** Function winShmMutexHeld() is used to assert() that the global mutex 
** is held when required. This function is only used as part of assert() 
** statements. e.g.
**
**   winShmEnterMutex()
**     assert( winShmMutexHeld() );
**   winEnterLeave()
*/
static void winShmEnterMutex(void){
  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
static void winShmLeaveMutex(void){
  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
#ifdef SQLITE_DEBUG
static int winShmMutexHeld(void) {
  return sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
#endif

/*
** Object used to represent a single file opened and mmapped to provide
** shared memory.  When multiple threads all reference the same
** log-summary, each thread has its own winFile object, but they all
** point to a single instance of this object.  In other words, each
** log-summary is opened only once per process.
**
** winShmMutexHeld() must be true when creating or destroying
** this object or while reading or writing the following fields:
**
**      nRef
**      pNext 
**
** The following fields are read-only after the object is created:
** 
**      fid
**      zFilename
**
** Either winShmNode.mutex must be held or winShmNode.nRef==0 and
** winShmMutexHeld() is true when reading or writing any other field
** in this structure.
**
** To avoid deadlocks, mutex and mutexBuf are always released in the
** reverse order that they are acquired.  mutexBuf is always acquired
** first and released last.  This invariant is check by asserting
** sqlite3_mutex_notheld() on mutex whenever mutexBuf is acquired or
** released.
*/
struct winShmNode {
  sqlite3_mutex *mutex;      /* Mutex to access this object */
  sqlite3_mutex *mutexBuf;   /* Mutex to access zBuf[] */
  char *zFilename;           /* Name of the file */
  winFile hFile;             /* File handle from winOpen */
  HANDLE hMap;               /* File handle from CreateFileMapping */
  DWORD lastErrno;           /* The Windows errno from the last I/O error */
  int szMap;                 /* Size of the mapping of file into memory */
  char *pMMapBuf;            /* Where currently mmapped().  NULL if unmapped */
  int nRef;                  /* Number of winShm objects pointing to this */
  winShm *pFirst;            /* All winShm objects pointing to this */
  winShmNode *pNext;         /* Next in list of all winShmNode objects */
#ifdef SQLITE_DEBUG
  u8 exclMask;               /* Mask of exclusive locks held */
  u8 sharedMask;             /* Mask of shared locks held */
  u8 nextShmId;              /* Next available winShm.id value */
#endif
};

/*
** A global array of all winShmNode objects.
**
** The winShmMutexHeld() must be true while reading or writing this list.
*/
static winShmNode *winShmNodeList = 0;

/*
** Structure used internally by this VFS to record the state of an
** open shared memory connection.
**
** winShm.pFile->mutex must be held while reading or writing the
** winShm.pNext and winShm.locks[] elements.
**
** The winShm.pFile element is initialized when the object is created
** and is read-only thereafter.
*/
struct winShm {
  winShmNode *pShmNode;      /* The underlying winShmNode object */
  winShm *pNext;             /* Next winShm with the same winShmNode */
  u8 lockState;              /* Current lock state */
  u8 hasMutex;               /* True if holding the winShmNode mutex */
  u8 hasMutexBuf;            /* True if holding pFile->mutexBuf */
  u8 sharedMask;             /* Mask of shared locks held */
  u8 exclMask;               /* Mask of exclusive locks held */
#ifdef SQLITE_DEBUG
  u8 id;                     /* Id of this connection with its winShmNode */
#endif
};

/*
** Size increment by which shared memory grows
*/
#define SQLITE_WIN_SHM_INCR  4096

/*
** Constants used for locking
*/
#define WIN_SHM_BASE      32        /* Byte offset of the first lock byte */
#define WIN_SHM_DMS       0x01      /* Mask for Dead-Man-Switch lock */
#define WIN_SHM_A         0x10      /* Mask for region locks... */
#define WIN_SHM_B         0x20
#define WIN_SHM_C         0x40
#define WIN_SHM_D         0x80

#ifdef SQLITE_DEBUG
/*
** Return a pointer to a nul-terminated string in static memory that
** describes a locking mask.  The string is of the form "MSABCD" with
** each character representing a lock.  "M" for MUTEX, "S" for DMS, 
** and "A" through "D" for the region locks.  If a lock is held, the
** letter is shown.  If the lock is not held, the letter is converted
** to ".".
**
** This routine is for debugging purposes only and does not appear
** in a production build.
*/
static const char *winShmLockString(u8 mask){
  static char zBuf[48];
  static int iBuf = 0;
  char *z;

  z = &zBuf[iBuf];
  iBuf += 8;
  if( iBuf>=sizeof(zBuf) ) iBuf = 0;

  z[0] = (mask & WIN_SHM_DMS)   ? 'S' : '.';
  z[1] = (mask & WIN_SHM_A)     ? 'A' : '.';
  z[2] = (mask & WIN_SHM_B)     ? 'B' : '.';
  z[3] = (mask & WIN_SHM_C)     ? 'C' : '.';
  z[4] = (mask & WIN_SHM_D)     ? 'D' : '.';
  z[5] = 0;
  return z;
}
#endif /* SQLITE_DEBUG */

/*
** Apply posix advisory locks for all bytes identified in lockMask.
**
** lockMask might contain multiple bits but all bits are guaranteed
** to be contiguous.
**
** Locks block if the mask is exactly WIN_SHM_C and are non-blocking
** otherwise.
*/
#define _SHM_UNLCK  1
#define _SHM_RDLCK  2
#define _SHM_WRLCK  3
static int winShmSystemLock(
  winShmNode *pFile,    /* Apply locks to this open shared-memory segment */
  int lockType,         /* _SHM_UNLCK, _SHM_RDLCK, or _SHM_WRLCK */
  u8 lockMask           /* Which bytes to lock or unlock */
){
  OVERLAPPED ovlp;
  DWORD dwFlags;
  int nBytes;           /* Number of bytes to lock */
  int i;                /* Offset into the locking byte range */
  int rc = 0;           /* Result code form Lock/UnlockFileEx() */
  u8 mask;              /* Mask of bits in lockMask */

  /* Access to the winShmNode object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) || pFile->nRef==0 );

  /* Initialize the locking parameters */
  if( lockMask==WIN_SHM_C && lockType!=_SHM_UNLCK ){
    dwFlags = 0;
    OSTRACE(("SHM-LOCK %d requesting blocking lock %s\n", 
             pFile->hFile.h,
             winShmLockString(lockMask)));
  }else{
    dwFlags = LOCKFILE_FAIL_IMMEDIATELY;
    OSTRACE(("SHM-LOCK %d requesting %s %s\n", 
             pFile->hFile.h,
             lockType!=_SHM_UNLCK ? "lock" : "unlock", 
             winShmLockString(lockMask)));
  }
  if( lockType == _SHM_WRLCK ) dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;

  /* Find the first bit in lockMask that is set */
  for(i=0, mask=0x01; mask!=0 && (lockMask&mask)==0; mask <<= 1, i++){}
  assert( mask!=0 );
  memset(&ovlp, 0, sizeof(OVERLAPPED));
  ovlp.Offset = i+WIN_SHM_BASE;
  nBytes = 1;

  /* Extend the locking range for each additional bit that is set */
  mask <<= 1;
  while( mask!=0 && (lockMask & mask)!=0 ){
    nBytes++;
    mask <<= 1;
  }

  /* Verify that all bits set in lockMask are contiguous */
  assert( mask==0 || (lockMask & ~(mask | (mask-1)))==0 );

  /* Release/Acquire the system-level lock */
  if( lockType==_SHM_UNLCK ){
    for(i=0; i<nBytes; i++, ovlp.Offset++){
      rc = UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
      if( !rc ) break;
    }
  }else{
    /* release old individual byte locks (if any)
    ** and set new individual byte locks */
    for(i=0; i<nBytes; i++, ovlp.Offset++){
      UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
      rc = LockFileEx(pFile->hFile.h, dwFlags, 0, 1, 0, &ovlp);
      if( !rc ) break;
    }
  }
  if( !rc ){
    OSTRACE(("SHM-LOCK %d %s ERROR 0x%08lx\n", 
             pFile->hFile.h,
             lockType==_SHM_UNLCK ? "UnlockFileEx" : "LockFileEx",
             GetLastError()));
    /* release individual byte locks (if any) */
    ovlp.Offset-=i;
    for(i=0; i<nBytes; i++, ovlp.Offset++){
      UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
    }
  }
  rc = (rc!=0) ? SQLITE_OK : SQLITE_BUSY;

  /* Update the global lock state and do debug tracing */
#ifdef SQLITE_DEBUG
  OSTRACE(("SHM-LOCK %d ", pFile->hFile.h));
  if( rc==SQLITE_OK ){
    if( lockType==_SHM_UNLCK ){
      OSTRACE(("unlock ok"));
      pFile->exclMask &= ~lockMask;
      pFile->sharedMask &= ~lockMask;
    }else if( lockType==_SHM_RDLCK ){
      OSTRACE(("read-lock ok"));
      pFile->exclMask &= ~lockMask;
      pFile->sharedMask |= lockMask;
    }else{
      assert( lockType==_SHM_WRLCK );
      OSTRACE(("write-lock ok"));
      pFile->exclMask |= lockMask;
      pFile->sharedMask &= ~lockMask;
    }
  }else{
    if( lockType==_SHM_UNLCK ){
      OSTRACE(("unlock failed"));
    }else if( lockType==_SHM_RDLCK ){
      OSTRACE(("read-lock failed"));
    }else{
      assert( lockType==_SHM_WRLCK );
      OSTRACE(("write-lock failed"));
    }
  }
  OSTRACE((" - change requested %s - afterwards %s:%s\n",
           winShmLockString(lockMask),
           winShmLockString(pFile->sharedMask),
           winShmLockString(pFile->exclMask)));
#endif

  return rc;
}

/*
** For connection p, unlock all of the locks identified by the unlockMask
** parameter.
*/
static int winShmUnlock(
  winShmNode *pFile,   /* The underlying shared-memory file */
  winShm *p,           /* The connection to be unlocked */
  u8 unlockMask         /* Mask of locks to be unlocked */
){
  int rc;      /* Result code */
  winShm *pX; /* For looping over all sibling connections */
  u8 allMask;  /* Union of locks held by connections other than "p" */

  /* Access to the winShmNode object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) );

  /* don't attempt to unlock anything we don't have locks for */
  if( (unlockMask & (p->exclMask|p->sharedMask)) != unlockMask ){
    OSTRACE(("SHM-LOCK %d unlocking more than we have locked - requested %s - have %s\n",
             pFile->hFile.h,
             winShmLockString(unlockMask),
             winShmLockString(p->exclMask|p->sharedMask)));
    unlockMask &= (p->exclMask|p->sharedMask);
  }

  /* Compute locks held by sibling connections */
  allMask = 0;
  for(pX=pFile->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
    allMask |= pX->sharedMask;
  }

  /* Unlock the system-level locks */
  if( (unlockMask & allMask)!=unlockMask ){
    rc = winShmSystemLock(pFile, _SHM_UNLCK, unlockMask & ~allMask);
  }else{
    rc = SQLITE_OK;
  }

  /* Undo the local locks */
  if( rc==SQLITE_OK ){
    p->exclMask &= ~unlockMask;
    p->sharedMask &= ~unlockMask;
  } 
  return rc;
}

/*
** Get reader locks for connection p on all locks in the readMask parameter.
*/
static int winShmSharedLock(
  winShmNode *pFile,   /* The underlying shared-memory file */
  winShm *p,           /* The connection to get the shared locks */
  u8 readMask           /* Mask of shared locks to be acquired */
){
  int rc;        /* Result code */
  winShm *pX;   /* For looping over all sibling connections */
  u8 allShared;  /* Union of locks held by connections other than "p" */

  /* Access to the winShmNode object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) );

  /* Find out which shared locks are already held by sibling connections.
  ** If any sibling already holds an exclusive lock, go ahead and return
  ** SQLITE_BUSY.
  */
  allShared = 0;
  for(pX=pFile->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    if( (pX->exclMask & readMask)!=0 ) return SQLITE_BUSY;
    allShared |= pX->sharedMask;
  }

  /* Get shared locks at the system level, if necessary */
  if( (~allShared) & readMask ){
    rc = winShmSystemLock(pFile, _SHM_RDLCK, readMask);
  }else{
    rc = SQLITE_OK;
  }

  /* Get the local shared locks */
  if( rc==SQLITE_OK ){
    p->sharedMask |= readMask;
  }
  return rc;
}

/*
** For connection p, get an exclusive lock on all locks identified in
** the writeMask parameter.
*/
static int winShmExclusiveLock(
  winShmNode *pFile,    /* The underlying shared-memory file */
  winShm *p,            /* The connection to get the exclusive locks */
  u8 writeMask           /* Mask of exclusive locks to be acquired */
){
  int rc;        /* Result code */
  winShm *pX;   /* For looping over all sibling connections */

  /* Access to the winShmNode object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) );

  /* Make sure no sibling connections hold locks that will block this
  ** lock.  If any do, return SQLITE_BUSY right away.
  */
  for(pX=pFile->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    if( (pX->exclMask & writeMask)!=0 ) return SQLITE_BUSY;
    if( (pX->sharedMask & writeMask)!=0 ) return SQLITE_BUSY;
  }

  /* Get the exclusive locks at the system level.  Then if successful
  ** also mark the local connection as being locked.
  */
  rc = winShmSystemLock(pFile, _SHM_WRLCK, writeMask);
  if( rc==SQLITE_OK ){
    p->sharedMask &= ~writeMask;
    p->exclMask |= writeMask;
  }
  return rc;
}

/*
** Purge the winShmNodeList list of all entries with winShmNode.nRef==0.
**
** This is not a VFS shared-memory method; it is a utility function called
** by VFS shared-memory methods.
*/
static void winShmPurge(void){
  winShmNode **pp;
  winShmNode *p;
  assert( winShmMutexHeld() );
  pp = &winShmNodeList;
  while( (p = *pp)!=0 ){
    if( p->nRef==0 ){
      if( p->mutex ) sqlite3_mutex_free(p->mutex);
      if( p->mutexBuf ) sqlite3_mutex_free(p->mutexBuf);
      if( p->pMMapBuf ){
        UnmapViewOfFile(p->pMMapBuf);
      }
      if( INVALID_HANDLE_VALUE != p->hMap ){
        CloseHandle(p->hMap);
      }
      if( p->hFile.h != INVALID_HANDLE_VALUE ) {
        winClose((sqlite3_file *)&p->hFile);
      }
      *pp = p->pNext;
      sqlite3_free(p);
    }else{
      pp = &p->pNext;
    }
  }
}

/* Forward references to VFS methods */
static int winOpen(sqlite3_vfs*,const char*,sqlite3_file*,int,int*);
static int winDelete(sqlite3_vfs *,const char*,int);

/*
** Open a shared-memory area.  This particular implementation uses
** mmapped files.
**
** zName is a filename used to identify the shared-memory area.  The
** implementation does not (and perhaps should not) use this name
** directly, but rather use it as a template for finding an appropriate
** name for the shared-memory storage.  In this implementation, the
** string "-index" is appended to zName and used as the name of the
** mmapped file.
**
** When opening a new shared-memory file, if no other instances of that
** file are currently open, in this process or in other processes, then
** the file must be truncated to zero length or have its header cleared.
*/
static int winShmOpen(
  sqlite3_file *fd      /* The file to which to attach shared memory */
){
  struct winFile *pDbFd;             /* Database to which to attach SHM */
  struct winShm *p;                  /* The connection to be opened */
  struct winShmNode *pShmNode = 0;   /* The underlying mmapped file */
  int rc;                            /* Result code */
  struct winShmNode *pNew;           /* Newly allocated winShmNode */
  int nName;                         /* Size of zName in bytes */

  pDbFd = (winFile*)fd;
  assert( pDbFd->pShm==0 );    /* Not previously opened */

  /* Allocate space for the new sqlite3_shm object.  Also speculatively
  ** allocate space for a new winShmNode and filename.
  */
  p = sqlite3_malloc( sizeof(*p) );
  if( p==0 ) return SQLITE_NOMEM;
  memset(p, 0, sizeof(*p));
  nName = sqlite3Strlen30(pDbFd->zPath);
  pNew = sqlite3_malloc( sizeof(*pShmNode) + nName + 15 );
  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_NOMEM;
  }
  memset(pNew, 0, sizeof(*pNew));
  pNew->zFilename = (char*)&pNew[1];
  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-wal-index", pDbFd->zPath);

  /* Look to see if there is an existing winShmNode that can be used.
  ** If no matching winShmNode currently exists, create a new one.
  */
  winShmEnterMutex();
  for(pShmNode = winShmNodeList; pShmNode; pShmNode=pShmNode->pNext){
    /* TBD need to come up with better match here.  Perhaps
    ** use FILE_ID_BOTH_DIR_INFO Structure.
    */
    if( sqlite3StrICmp(pShmNode->zFilename, pNew->zFilename)==0 ) break;
  }
  if( pShmNode ){
    sqlite3_free(pNew);
  }else{
    pShmNode = pNew;
    pNew = 0;
    pShmNode->pMMapBuf = NULL;
    pShmNode->hMap = INVALID_HANDLE_VALUE;
    ((winFile*)(&pShmNode->hFile))->h = INVALID_HANDLE_VALUE;
    pShmNode->pNext = winShmNodeList;
    winShmNodeList = pShmNode;

    pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pShmNode->mutex==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    pShmNode->mutexBuf = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pShmNode->mutexBuf==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    rc = winOpen(pDbFd->pVfs,
                 pShmNode->zFilename,             /* Name of the file (UTF-8) */
                 (sqlite3_file*)&pShmNode->hFile,  /* File handle here */
                 SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, /* Mode flags */
                 0);
    if( SQLITE_OK!=rc ){
      rc = SQLITE_CANTOPEN_BKPT;
      goto shm_open_err;
    }

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS)==SQLITE_OK ){
      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, 0);
    }
    if( rc==SQLITE_OK ){
      rc = winShmSystemLock(pShmNode, _SHM_RDLCK, WIN_SHM_DMS);
    }
    if( rc ) goto shm_open_err;
  }

  /* Make the new connection a child of the winShmNode */
  p->pShmNode = pShmNode;
  p->pNext = pShmNode->pFirst;
#ifdef SQLITE_DEBUG
  p->id = pShmNode->nextShmId++;
#endif
  pShmNode->pFirst = p;
  pShmNode->nRef++;
  pDbFd->pShm = p;
  winShmLeaveMutex();
  return SQLITE_OK;

  /* Jump here on any error */
shm_open_err:
  winShmSystemLock(pShmNode, _SHM_UNLCK, WIN_SHM_DMS);
  winShmPurge();                 /* This call frees pShmNode if required */
  sqlite3_free(p);
  sqlite3_free(pNew);
  winShmLeaveMutex();
  return rc;
}

/*
** Close a connection to shared-memory.  Delete the underlying 
** storage if deleteFlag is true.
*/
static int winShmClose(
  sqlite3_file *fd,          /* Database holding shared memory */
  int deleteFlag             /* Delete after closing if true */
){
  winFile *pDbFd;       /* Database holding shared-memory */
  winShm *p;            /* The connection to be closed */
  winShmNode *pShmNode; /* The underlying shared-memory file */
  winShm **pp;          /* For looping over sibling connections */

  pDbFd = (winFile*)fd;
  p = pDbFd->pShm;
  pShmNode = p->pShmNode;

  /* Verify that the connection being closed holds no locks */
  assert( p->exclMask==0 );
  assert( p->sharedMask==0 );

  /* Remove connection p from the set of connections associated
  ** with pShmNode */
  sqlite3_mutex_enter(pShmNode->mutex);
  for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
  *pp = p->pNext;

  /* Free the connection p */
  sqlite3_free(p);
  pDbFd->pShm = 0;
  sqlite3_mutex_leave(pShmNode->mutex);

  /* If pShmNode->nRef has reached 0, then close the underlying
  ** shared-memory file, too */
  winShmEnterMutex();
  assert( pShmNode->nRef>0 );
  pShmNode->nRef--;
  if( pShmNode->nRef==0 ){
    if( deleteFlag ) winDelete(pDbFd->pVfs, pShmNode->zFilename, 0);
    winShmPurge();
  }
  winShmLeaveMutex();

  return SQLITE_OK;
}

/*
** Query and/or changes the size of the underlying storage for
** a shared-memory segment.  The reqSize parameter is the new size
** of the underlying storage, or -1 to do just a query.  The size
** of the underlying storage (after resizing if resizing occurs) is
** written into pNewSize.
**
** This routine does not (necessarily) change the size of the mapping 
** of the underlying storage into memory.  Use xShmGet() to change
** the mapping size.
**
** The reqSize parameter is the minimum size requested.  The implementation
** is free to expand the storage to some larger amount if it chooses.
*/
static int winShmSize(
  sqlite3_file *fd,         /* Database holding the shared memory */
  int reqSize,              /* Requested size.  -1 for query only */
  int *pNewSize             /* Write new size here */
){
  winFile *pDbFd = (winFile*)fd;
  winShm *p = pDbFd->pShm;
  winShmNode *pShmNode = p->pShmNode;
  int rc = SQLITE_OK;

  *pNewSize = 0;
  if( reqSize>=0 ){
    sqlite3_int64 sz;
    rc = winFileSize((sqlite3_file *)&pShmNode->hFile, &sz);
    if( SQLITE_OK==rc ){
      reqSize = (reqSize + SQLITE_WIN_SHM_INCR - 1)/SQLITE_WIN_SHM_INCR;
      reqSize *= SQLITE_WIN_SHM_INCR;
      if( reqSize>sz ){
        rc = winTruncate((sqlite3_file *)&pShmNode->hFile, reqSize);
      }
    }
  }
  if( SQLITE_OK==rc ){
    sqlite3_int64 sz;
    rc = winFileSize((sqlite3_file *)&pShmNode->hFile, &sz);
    if( SQLITE_OK==rc ){
      *pNewSize = (int)sz;
    }else{
      rc = SQLITE_IOERR;
    }
  }
  return rc;
}


/*
** Map the shared storage into memory.  The minimum size of the
** mapping should be reqMapSize if reqMapSize is positive.  If
** reqMapSize is zero or negative, the implementation can choose
** whatever mapping size is convenient.
**
** *ppBuf is made to point to the memory which is a mapping of the
** underlying storage.  A mutex is acquired to prevent other threads
** from running while *ppBuf is in use in order to prevent other threads
** remapping *ppBuf out from under this thread.  The winShmRelease()
** call will release the mutex.  However, if the lock state is CHECKPOINT,
** the mutex is not acquired because CHECKPOINT will never remap the
** buffer.  RECOVER might remap, though, so CHECKPOINT will acquire
** the mutex if and when it promotes to RECOVER.
**
** RECOVER needs to be atomic.  The same mutex that prevents *ppBuf from
** being remapped also prevents more than one thread from being in
** RECOVER at a time.  But, RECOVER sometimes wants to remap itself.
** To prevent RECOVER from losing its lock while remapping, the
** mutex is not released by winShmRelease() when in RECOVER.
**
** *pNewMapSize is set to the size of the mapping.
**
** *ppBuf and *pNewMapSize might be NULL and zero if no space has
** yet been allocated to the underlying storage.
*/
static int winShmGet(
  sqlite3_file *fd,        /* The database file holding the shared memory */
  int reqMapSize,          /* Requested size of mapping. -1 means don't care */
  int *pNewMapSize,        /* Write new size of mapping here */
  void **ppBuf             /* Write mapping buffer origin here */
){
  winFile *pDbFd = (winFile*)fd;
  winShm *p = pDbFd->pShm;
  winShmNode *pShmNode = p->pShmNode;
  int rc = SQLITE_OK;

  if( p->lockState!=SQLITE_SHM_CHECKPOINT && p->hasMutexBuf==0 ){
    assert( sqlite3_mutex_notheld(pShmNode->mutex) );
    sqlite3_mutex_enter(pShmNode->mutexBuf);
    p->hasMutexBuf = 1;
  }
  sqlite3_mutex_enter(pShmNode->mutex);
  if( pShmNode->szMap==0 || reqMapSize>pShmNode->szMap ){
    int actualSize;
    if( winShmSize(fd, -1, &actualSize)==SQLITE_OK
     && reqMapSize<actualSize
    ){
      reqMapSize = actualSize;
    }
    if( pShmNode->pMMapBuf ){
      if( !UnmapViewOfFile(pShmNode->pMMapBuf) ){
        pShmNode->lastErrno = GetLastError();
        rc = SQLITE_IOERR;
      }
      CloseHandle(pShmNode->hMap);
      pShmNode->hMap = INVALID_HANDLE_VALUE;
    }
    if( SQLITE_OK == rc ){
      pShmNode->pMMapBuf = 0;
      if( reqMapSize == 0 ){
        /* can't create 0 byte file mapping in Windows */
        pShmNode->szMap = 0;
      }else{
        /* create the file mapping object */
        if( INVALID_HANDLE_VALUE == pShmNode->hMap ){
          /* TBD provide an object name to each file
          ** mapping so it can be re-used across processes.
          */
          pShmNode->hMap = CreateFileMapping(pShmNode->hFile.h,
                                          NULL,
                                          PAGE_READWRITE,
                                          0,
                                          reqMapSize,
                                          NULL);
        }
        if( NULL==pShmNode->hMap ){
          pShmNode->lastErrno = GetLastError();
          rc = SQLITE_IOERR;
          pShmNode->szMap = 0;
          pShmNode->hMap = INVALID_HANDLE_VALUE;
        }else{
          pShmNode->pMMapBuf = MapViewOfFile(pShmNode->hMap,
                                          FILE_MAP_WRITE | FILE_MAP_READ,
                                          0,
                                          0,
                                          reqMapSize);
          if( !pShmNode->pMMapBuf ){
            pShmNode->lastErrno = GetLastError();
            rc = SQLITE_IOERR;
            pShmNode->szMap = 0;
          }else{
            pShmNode->szMap = reqMapSize;
          }
        }
      }
    }
  }
  *pNewMapSize = pShmNode->szMap;
  *ppBuf = pShmNode->pMMapBuf;
  sqlite3_mutex_leave(pShmNode->mutex);
  return rc;
}

/*
** Release the lock held on the shared memory segment so that other
** threads are free to resize it if necessary.
**
** If the lock is not currently held, this routine is a harmless no-op.
**
** If the shared-memory object is in lock state RECOVER, then we do not
** really want to release the lock, so in that case too, this routine
** is a no-op.
*/
static int winShmRelease(sqlite3_file *fd){
  winFile *pDbFd = (winFile*)fd;
  winShm *p = pDbFd->pShm;
  if( p->hasMutexBuf && p->lockState!=SQLITE_SHM_RECOVER ){
    winShmNode *pShmNode = p->pShmNode;
    assert( sqlite3_mutex_notheld(pShmNode->mutex) );
    sqlite3_mutex_leave(pShmNode->mutexBuf);
    p->hasMutexBuf = 0;
  }
  return SQLITE_OK;
}

/*
** Symbolic names for LOCK states used for debugging.
*/
#ifdef SQLITE_DEBUG
static const char *azLkName[] = {
  "UNLOCK",
  "READ",
  "READ_FULL",
  "WRITE",
  "PENDING",
  "CHECKPOINT",
  "RECOVER"
};
#endif


/*
** Change the lock state for a shared-memory segment.
*/
static int winShmLock(
  sqlite3_file *fd,          /* Database holding the shared memory */
  int desiredLock,           /* One of SQLITE_SHM_xxxxx locking states */
  int *pGotLock              /* The lock you actually got */
){
  winFile *pDbFd = (winFile*)fd;
  winShm *p = pDbFd->pShm;
  winShmNode *pShmNode = p->pShmNode;
  int rc = SQLITE_PROTOCOL;

  /* Note that SQLITE_SHM_READ_FULL and SQLITE_SHM_PENDING are never
  ** directly requested; they are side effects from requesting
  ** SQLITE_SHM_READ and SQLITE_SHM_CHECKPOINT, respectively.
  */
  assert( desiredLock==SQLITE_SHM_UNLOCK
       || desiredLock==SQLITE_SHM_READ
       || desiredLock==SQLITE_SHM_WRITE
       || desiredLock==SQLITE_SHM_CHECKPOINT
       || desiredLock==SQLITE_SHM_RECOVER );

  /* Return directly if this is just a lock state query, or if
  ** the connection is already in the desired locking state.
  */
  if( desiredLock==p->lockState
   || (desiredLock==SQLITE_SHM_READ && p->lockState==SQLITE_SHM_READ_FULL)
  ){
    OSTRACE(("SHM-LOCK %d shmid-%d, pid-%d request %s and got %s\n",
             pShmNode->hFile.h,
             p->id, (int)GetCurrentProcessId(), azLkName[desiredLock],
             azLkName[p->lockState]));
    if( pGotLock ) *pGotLock = p->lockState;
    return SQLITE_OK;
  }

  OSTRACE(("SHM-LOCK %d shmid-%d, pid-%d request %s->%s\n",
           pShmNode->hFile.h,
           p->id, (int)GetCurrentProcessId(), azLkName[p->lockState], 
           azLkName[desiredLock]));
  
  if( desiredLock==SQLITE_SHM_RECOVER && !p->hasMutexBuf ){
    assert( sqlite3_mutex_notheld(pShmNode->mutex) );
    sqlite3_mutex_enter(pShmNode->mutexBuf);
    p->hasMutexBuf = 1;
  }
  sqlite3_mutex_enter(pShmNode->mutex);
  switch( desiredLock ){
    case SQLITE_SHM_UNLOCK: {
      assert( p->lockState!=SQLITE_SHM_RECOVER );
      winShmUnlock(pShmNode, p, WIN_SHM_A|WIN_SHM_B|WIN_SHM_C|WIN_SHM_D);
      rc = SQLITE_OK;
      p->lockState = SQLITE_SHM_UNLOCK;
      break;
    }
    case SQLITE_SHM_READ: {
      if( p->lockState==SQLITE_SHM_UNLOCK ){
        int nAttempt;
        rc = SQLITE_BUSY;
        assert( p->lockState==SQLITE_SHM_UNLOCK );
        for(nAttempt=0; nAttempt<5 && rc==SQLITE_BUSY; nAttempt++){
          rc = winShmSharedLock(pShmNode, p, WIN_SHM_A|WIN_SHM_B);
          if( rc==SQLITE_BUSY ){
            rc = winShmSharedLock(pShmNode, p, WIN_SHM_D);
            if( rc==SQLITE_OK ){
              p->lockState = SQLITE_SHM_READ_FULL;
            }
          }else{
            winShmUnlock(pShmNode, p, WIN_SHM_B);
            p->lockState = SQLITE_SHM_READ;
          }
        }
      }else{
       assert( p->lockState==SQLITE_SHM_WRITE
               || p->lockState==SQLITE_SHM_RECOVER );
        rc = winShmSharedLock(pShmNode, p, WIN_SHM_A);
        winShmUnlock(pShmNode, p, WIN_SHM_C|WIN_SHM_D);
        p->lockState = SQLITE_SHM_READ;
      }
      break;
    }
    case SQLITE_SHM_WRITE: {
      assert( p->lockState==SQLITE_SHM_READ 
              || p->lockState==SQLITE_SHM_READ_FULL );
      rc = winShmExclusiveLock(pShmNode, p, WIN_SHM_C|WIN_SHM_D);
      if( rc==SQLITE_OK ){
        p->lockState = SQLITE_SHM_WRITE;
      }
      break;
    }
    case SQLITE_SHM_CHECKPOINT: {
      assert( p->lockState==SQLITE_SHM_UNLOCK
           || p->lockState==SQLITE_SHM_PENDING
      );
      if( p->lockState==SQLITE_SHM_UNLOCK ){
        rc = winShmExclusiveLock(pShmNode, p, WIN_SHM_B|WIN_SHM_C);
        if( rc==SQLITE_OK ){
          p->lockState = SQLITE_SHM_PENDING;
        }
      }
      if( p->lockState==SQLITE_SHM_PENDING ){
        rc = winShmExclusiveLock(pShmNode, p, WIN_SHM_A);
        if( rc==SQLITE_OK ){
          p->lockState = SQLITE_SHM_CHECKPOINT;
        }
      }
      break;
    }
    default: {
      assert( desiredLock==SQLITE_SHM_RECOVER );
      assert( p->lockState==SQLITE_SHM_READ
           || p->lockState==SQLITE_SHM_READ_FULL
      );
      assert( sqlite3_mutex_held(pShmNode->mutexBuf) );
      rc = winShmExclusiveLock(pShmNode, p, WIN_SHM_C);
      if( rc==SQLITE_OK ){
        p->lockState = SQLITE_SHM_RECOVER;
      }
      break;
    }
  }
  sqlite3_mutex_leave(pShmNode->mutex);
  OSTRACE(("SHM-LOCK %d shmid-%d, pid-%d got %s\n",
           pShmNode->hFile.h, 
           p->id, (int)GetCurrentProcessId(), azLkName[p->lockState]));
  if( pGotLock ) *pGotLock = p->lockState;
  return rc;
}

#else
# define winShmOpen    0
# define winShmSize    0
# define winShmGet     0
# define winShmRelease 0
# define winShmLock    0
# define winShmClose   0
#endif /* #ifndef SQLITE_OMIT_WAL */
/*
***************************** End Shared Memory *****************************
****************************************************************************/

/*
** This vector defines all the methods that can operate on an
** sqlite3_file for win32.
*/
static const sqlite3_io_methods winIoMethod = {
  2,                        /* iVersion */
  winClose,
  winRead,
  winWrite,
  winTruncate,
  winSync,
  winFileSize,
  winLock,
  winUnlock,
  winCheckReservedLock,
  winFileControl,
  winSectorSize,
  winDeviceCharacteristics,
  winShmOpen,              /* xShmOpen */
  winShmSize,              /* xShmSize */
  winShmGet,               /* xShmGet */
  winShmRelease,           /* xShmRelease */
  winShmLock,              /* xShmLock */
  winShmClose              /* xShmClose */
};

/***************************************************************************
** Here ends the I/O methods that form the sqlite3_io_methods object.
**
** The next block of code implements the VFS methods.
****************************************************************************/
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                   "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPath);
  j = sqlite3Strlen30(zBuf);
  sqlite3_randomness(20, &zBuf[j]);
  for(i=0; i<20; i++, j++){
    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
  }
  zBuf[j] = 0;
  OSTRACE2("TEMP FILENAME: %s\n", zBuf);
  return SQLITE_OK; 
}

/*
** The return value of getLastErrorMsg
** is zero if the error message fits in the buffer, or non-zero
** otherwise (if the message was truncated).







|







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                   "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPath);
  j = sqlite3Strlen30(zBuf);
  sqlite3_randomness(20, &zBuf[j]);
  for(i=0; i<20; i++, j++){
    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
  }
  zBuf[j] = 0;
  OSTRACE(("TEMP FILENAME: %s\n", zBuf));
  return SQLITE_OK; 
}

/*
** The return value of getLastErrorMsg
** is zero if the error message fits in the buffer, or non-zero
** otherwise (if the message was truncated).
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      *pOutFlags = SQLITE_OPEN_READONLY;
    }
  }
  memset(pFile, 0, sizeof(*pFile));
  pFile->pMethod = &winIoMethod;
  pFile->h = h;
  pFile->lastErrno = NO_ERROR;



  pFile->sectorSize = getSectorSize(pVfs, zUtf8Name);
#if SQLITE_OS_WINCE
  if( (flags & (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)) ==
               (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)
       && !winceCreateLock(zName, pFile)
  ){
    CloseHandle(h);







>
>
>







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      *pOutFlags = SQLITE_OPEN_READONLY;
    }
  }
  memset(pFile, 0, sizeof(*pFile));
  pFile->pMethod = &winIoMethod;
  pFile->h = h;
  pFile->lastErrno = NO_ERROR;
  pFile->pVfs = pVfs;
  pFile->pShm = 0;
  pFile->zPath = zName;
  pFile->sectorSize = getSectorSize(pVfs, zUtf8Name);
#if SQLITE_OS_WINCE
  if( (flags & (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)) ==
               (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)
       && !winceCreateLock(zName, pFile)
  ){
    CloseHandle(h);
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    }while(   (   ((rc = GetFileAttributesA(zConverted)) != INVALID_FILE_ATTRIBUTES)
               || ((error = GetLastError()) == ERROR_ACCESS_DENIED))
           && (++cnt < MX_DELETION_ATTEMPTS)
           && (Sleep(100), 1) );
#endif
  }
  free(zConverted);
  OSTRACE(("DELETE \"%s\" %s\n", zFilename, (   (rc == INVALID_FILE_ATTRIBUTES) 

                                             && (error == ERROR_FILE_NOT_FOUND)) ? "ok" : "failed" ));

  return (   (rc == INVALID_FILE_ATTRIBUTES) 
          && (error == ERROR_FILE_NOT_FOUND)) ? SQLITE_OK : SQLITE_IOERR_DELETE;
}

/*
** Check the existance and status of a file.
*/







|
>
|
>







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    }while(   (   ((rc = GetFileAttributesA(zConverted)) != INVALID_FILE_ATTRIBUTES)
               || ((error = GetLastError()) == ERROR_ACCESS_DENIED))
           && (++cnt < MX_DELETION_ATTEMPTS)
           && (Sleep(100), 1) );
#endif
  }
  free(zConverted);
  OSTRACE(("DELETE \"%s\" %s\n", zFilename,
       ( (rc==INVALID_FILE_ATTRIBUTES) && (error==ERROR_FILE_NOT_FOUND)) ?
         "ok" : "failed" ));
 
  return (   (rc == INVALID_FILE_ATTRIBUTES) 
          && (error == ERROR_FILE_NOT_FOUND)) ? SQLITE_OK : SQLITE_IOERR_DELETE;
}

/*
** Check the existance and status of a file.
*/
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** sqlite3_errmsg(), possibly making IO errors easier to debug.
*/
static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
  UNUSED_PARAMETER(pVfs);
  return getLastErrorMsg(nBuf, zBuf);
}

#ifndef SQLITE_OMIT_WAL

/*
** Helper functions to obtain and relinquish the global mutex. The
** global mutex is used to protect the winLockInfo objects used by 
** this file, all of which may be shared by multiple threads.
**
** Function winShmMutexHeld() is used to assert() that the global mutex 
** is held when required. This function is only used as part of assert() 
** statements. e.g.
**
**   winShmEnterMutex()
**     assert( winShmMutexHeld() );
**   winEnterLeave()
*/
static void winShmEnterMutex(void){
  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
static void winShmLeaveMutex(void){
  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
#ifdef SQLITE_DEBUG
static int winShmMutexHeld(void) {
  return sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
#endif

/* Forward reference */
typedef struct winShm winShm;
typedef struct winShmFile winShmFile;

/*
** Object used to represent a single file opened and mmapped to provide
** shared memory.  When multiple threads all reference the same
** log-summary, each thread has its own winFile object, but they all
** point to a single instance of this object.  In other words, each
** log-summary is opened only once per process.
**
** winShmMutexHeld() must be true when creating or destroying
** this object or while reading or writing the following fields:
**
**      nRef
**      pNext 
**
** The following fields are read-only after the object is created:
** 
**      fid
**      zFilename
**
** Either winShmFile.mutex must be held or winShmFile.nRef==0 and
** winShmMutexHeld() is true when reading or writing any other field
** in this structure.
**
** To avoid deadlocks, mutex and mutexBuf are always released in the
** reverse order that they are acquired.  mutexBuf is always acquired
** first and released last.  This invariant is check by asserting
** sqlite3_mutex_notheld() on mutex whenever mutexBuf is acquired or
** released.
*/
struct winShmFile {
  sqlite3_mutex *mutex;      /* Mutex to access this object */
  sqlite3_mutex *mutexBuf;   /* Mutex to access zBuf[] */
  char *zFilename;           /* Name of the file */
  winFile hFile;             /* File handle from winOpen */
  HANDLE hMap;               /* File handle from CreateFileMapping */
  DWORD lastErrno;           /* The Windows errno from the last I/O error */
  int szMap;                 /* Size of the mapping of file into memory */
  char *pMMapBuf;            /* Where currently mmapped().  NULL if unmapped */
  int nRef;                  /* Number of winShm objects pointing to this */
  winShm *pFirst;            /* All winShm objects pointing to this */
  winShmFile *pNext;         /* Next in list of all winShmFile objects */
#ifdef SQLITE_DEBUG
  u8 exclMask;               /* Mask of exclusive locks held */
  u8 sharedMask;             /* Mask of shared locks held */
  u8 nextShmId;              /* Next available winShm.id value */
#endif
};

/*
** A global array of all winShmFile objects.
**
** The winShmMutexHeld() must be true while reading or writing this list.
*/
static winShmFile *winShmFileList = 0;

/*
** Structure used internally by this VFS to record the state of an
** open shared memory connection.
**
** winShm.pFile->mutex must be held while reading or writing the
** winShm.pNext and winShm.locks[] elements.
**
** The winShm.pFile element is initialized when the object is created
** and is read-only thereafter.
*/
struct winShm {
  winShmFile *pFile;         /* The underlying winShmFile object */
  winShm *pNext;             /* Next winShm with the same winShmFile */
  u8 lockState;              /* Current lock state */
  u8 hasMutex;               /* True if holding the winShmFile mutex */
  u8 hasMutexBuf;            /* True if holding pFile->mutexBuf */
  u8 sharedMask;             /* Mask of shared locks held */
  u8 exclMask;               /* Mask of exclusive locks held */
#ifdef SQLITE_DEBUG
  u8 id;                     /* Id of this connection with its winShmFile */
#endif
};

/*
** Size increment by which shared memory grows
*/
#define SQLITE_WIN_SHM_INCR  4096

/*
** Constants used for locking
*/
#define WIN_SHM_BASE      32        /* Byte offset of the first lock byte */
#define WIN_SHM_DMS       0x01      /* Mask for Dead-Man-Switch lock */
#define WIN_SHM_A         0x10      /* Mask for region locks... */
#define WIN_SHM_B         0x20
#define WIN_SHM_C         0x40
#define WIN_SHM_D         0x80

#ifdef SQLITE_DEBUG
/*
** Return a pointer to a nul-terminated string in static memory that
** describes a locking mask.  The string is of the form "MSABCD" with
** each character representing a lock.  "M" for MUTEX, "S" for DMS, 
** and "A" through "D" for the region locks.  If a lock is held, the
** letter is shown.  If the lock is not held, the letter is converted
** to ".".
**
** This routine is for debugging purposes only and does not appear
** in a production build.
*/
static const char *winShmLockString(u8 mask){
  static char zBuf[48];
  static int iBuf = 0;
  char *z;

  z = &zBuf[iBuf];
  iBuf += 8;
  if( iBuf>=sizeof(zBuf) ) iBuf = 0;

  z[0] = (mask & WIN_SHM_DMS)   ? 'S' : '.';
  z[1] = (mask & WIN_SHM_A)     ? 'A' : '.';
  z[2] = (mask & WIN_SHM_B)     ? 'B' : '.';
  z[3] = (mask & WIN_SHM_C)     ? 'C' : '.';
  z[4] = (mask & WIN_SHM_D)     ? 'D' : '.';
  z[5] = 0;
  return z;
}
#endif /* SQLITE_DEBUG */

/*
** Apply posix advisory locks for all bytes identified in lockMask.
**
** lockMask might contain multiple bits but all bits are guaranteed
** to be contiguous.
**
** Locks block if the mask is exactly WIN_SHM_C and are non-blocking
** otherwise.
*/
#define _SHM_UNLCK  1
#define _SHM_RDLCK  2
#define _SHM_WRLCK  3
static int winShmSystemLock(
  winShmFile *pFile,    /* Apply locks to this open shared-memory segment */
  int lockType,         /* _SHM_UNLCK, _SHM_RDLCK, or _SHM_WRLCK */
  u8 lockMask           /* Which bytes to lock or unlock */
){
  OVERLAPPED ovlp;
  DWORD dwFlags;
  int nBytes;           /* Number of bytes to lock */
  int i;                /* Offset into the locking byte range */
  int rc = 0;           /* Result code form Lock/UnlockFileEx() */
  u8 mask;              /* Mask of bits in lockMask */

  /* Access to the winShmFile object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) || pFile->nRef==0 );

  /* Initialize the locking parameters */
  if( lockMask==WIN_SHM_C && lockType!=_SHM_UNLCK ){
    dwFlags = 0;
    OSTRACE(("SHM-LOCK %d requesting blocking lock %s\n", 
             pFile->hFile.h,
             winShmLockString(lockMask)));
  }else{
    dwFlags = LOCKFILE_FAIL_IMMEDIATELY;
    OSTRACE(("SHM-LOCK %d requesting %s %s\n", 
             pFile->hFile.h,
             lockType!=_SHM_UNLCK ? "lock" : "unlock", 
             winShmLockString(lockMask)));
  }
  if( lockType == _SHM_WRLCK ) dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;

  /* Find the first bit in lockMask that is set */
  for(i=0, mask=0x01; mask!=0 && (lockMask&mask)==0; mask <<= 1, i++){}
  assert( mask!=0 );
  memset(&ovlp, 0, sizeof(OVERLAPPED));
  ovlp.Offset = i+WIN_SHM_BASE;
  nBytes = 1;

  /* Extend the locking range for each additional bit that is set */
  mask <<= 1;
  while( mask!=0 && (lockMask & mask)!=0 ){
    nBytes++;
    mask <<= 1;
  }

  /* Verify that all bits set in lockMask are contiguous */
  assert( mask==0 || (lockMask & ~(mask | (mask-1)))==0 );

  /* Release/Acquire the system-level lock */
  if( lockType==_SHM_UNLCK ){
    for(i=0; i<nBytes; i++, ovlp.Offset++){
      rc = UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
      if( !rc ) break;
    }
  }else{
    /* release old individual byte locks (if any)
    ** and set new individual byte locks */
    for(i=0; i<nBytes; i++, ovlp.Offset++){
      UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
      rc = LockFileEx(pFile->hFile.h, dwFlags, 0, 1, 0, &ovlp);
      if( !rc ) break;
    }
  }
  if( !rc ){
    OSTRACE(("SHM-LOCK %d %s ERROR 0x%08lx\n", 
             pFile->hFile.h,
             lockType==_SHM_UNLCK ? "UnlockFileEx" : "LockFileEx", GetLastError()));
    /* release individual byte locks (if any) */
    ovlp.Offset-=i;
    for(i=0; i<nBytes; i++, ovlp.Offset++){
      UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
    }
  }
  rc = (rc!=0) ? SQLITE_OK : SQLITE_BUSY;

  /* Update the global lock state and do debug tracing */
#ifdef SQLITE_DEBUG
  OSTRACE(("SHM-LOCK %d ", pFile->hFile.h));
  if( rc==SQLITE_OK ){
    if( lockType==_SHM_UNLCK ){
      OSTRACE(("unlock ok"));
      pFile->exclMask &= ~lockMask;
      pFile->sharedMask &= ~lockMask;
    }else if( lockType==_SHM_RDLCK ){
      OSTRACE(("read-lock ok"));
      pFile->exclMask &= ~lockMask;
      pFile->sharedMask |= lockMask;
    }else{
      assert( lockType==_SHM_WRLCK );
      OSTRACE(("write-lock ok"));
      pFile->exclMask |= lockMask;
      pFile->sharedMask &= ~lockMask;
    }
  }else{
    if( lockType==_SHM_UNLCK ){
      OSTRACE(("unlock failed"));
    }else if( lockType==_SHM_RDLCK ){
      OSTRACE(("read-lock failed"));
    }else{
      assert( lockType==_SHM_WRLCK );
      OSTRACE(("write-lock failed"));
    }
  }
  OSTRACE((" - change requested %s - afterwards %s:%s\n",
           winShmLockString(lockMask),
           winShmLockString(pFile->sharedMask),
           winShmLockString(pFile->exclMask)));
#endif

  return rc;
}

/*
** For connection p, unlock all of the locks identified by the unlockMask
** parameter.
*/
static int winShmUnlock(
  winShmFile *pFile,   /* The underlying shared-memory file */
  winShm *p,           /* The connection to be unlocked */
  u8 unlockMask         /* Mask of locks to be unlocked */
){
  int rc;      /* Result code */
  winShm *pX; /* For looping over all sibling connections */
  u8 allMask;  /* Union of locks held by connections other than "p" */

  /* Access to the winShmFile object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) );

  /* don't attempt to unlock anything we don't have locks for */
  if( (unlockMask & (p->exclMask|p->sharedMask)) != unlockMask ){
    OSTRACE(("SHM-LOCK %d unlocking more than we have locked - requested %s - have %s\n",
             pFile->hFile.h,
             winShmLockString(unlockMask),
             winShmLockString(p->exclMask|p->sharedMask)));
    unlockMask &= (p->exclMask|p->sharedMask);
  }

  /* Compute locks held by sibling connections */
  allMask = 0;
  for(pX=pFile->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
    allMask |= pX->sharedMask;
  }

  /* Unlock the system-level locks */
  if( (unlockMask & allMask)!=unlockMask ){
    rc = winShmSystemLock(pFile, _SHM_UNLCK, unlockMask & ~allMask);
  }else{
    rc = SQLITE_OK;
  }

  /* Undo the local locks */
  if( rc==SQLITE_OK ){
    p->exclMask &= ~unlockMask;
    p->sharedMask &= ~unlockMask;
  } 
  return rc;
}

/*
** Get reader locks for connection p on all locks in the readMask parameter.
*/
static int winShmSharedLock(
  winShmFile *pFile,   /* The underlying shared-memory file */
  winShm *p,           /* The connection to get the shared locks */
  u8 readMask           /* Mask of shared locks to be acquired */
){
  int rc;        /* Result code */
  winShm *pX;   /* For looping over all sibling connections */
  u8 allShared;  /* Union of locks held by connections other than "p" */

  /* Access to the winShmFile object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) );

  /* Find out which shared locks are already held by sibling connections.
  ** If any sibling already holds an exclusive lock, go ahead and return
  ** SQLITE_BUSY.
  */
  allShared = 0;
  for(pX=pFile->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    if( (pX->exclMask & readMask)!=0 ) return SQLITE_BUSY;
    allShared |= pX->sharedMask;
  }

  /* Get shared locks at the system level, if necessary */
  if( (~allShared) & readMask ){
    rc = winShmSystemLock(pFile, _SHM_RDLCK, readMask);
  }else{
    rc = SQLITE_OK;
  }

  /* Get the local shared locks */
  if( rc==SQLITE_OK ){
    p->sharedMask |= readMask;
  }
  return rc;
}

/*
** For connection p, get an exclusive lock on all locks identified in
** the writeMask parameter.
*/
static int winShmExclusiveLock(
  winShmFile *pFile,    /* The underlying shared-memory file */
  winShm *p,            /* The connection to get the exclusive locks */
  u8 writeMask           /* Mask of exclusive locks to be acquired */
){
  int rc;        /* Result code */
  winShm *pX;   /* For looping over all sibling connections */

  /* Access to the winShmFile object is serialized by the caller */
  assert( sqlite3_mutex_held(pFile->mutex) );

  /* Make sure no sibling connections hold locks that will block this
  ** lock.  If any do, return SQLITE_BUSY right away.
  */
  for(pX=pFile->pFirst; pX; pX=pX->pNext){
    if( pX==p ) continue;
    if( (pX->exclMask & writeMask)!=0 ) return SQLITE_BUSY;
    if( (pX->sharedMask & writeMask)!=0 ) return SQLITE_BUSY;
  }

  /* Get the exclusive locks at the system level.  Then if successful
  ** also mark the local connection as being locked.
  */
  rc = winShmSystemLock(pFile, _SHM_WRLCK, writeMask);
  if( rc==SQLITE_OK ){
    p->sharedMask &= ~writeMask;
    p->exclMask |= writeMask;
  }
  return rc;
}

/*
** Purge the winShmFileList list of all entries with winShmFile.nRef==0.
**
** This is not a VFS shared-memory method; it is a utility function called
** by VFS shared-memory methods.
*/
static void winShmPurge(void){
  winShmFile **pp;
  winShmFile *p;
  assert( winShmMutexHeld() );
  pp = &winShmFileList;
  while( (p = *pp)!=0 ){
    if( p->nRef==0 ){
      if( p->mutex ) sqlite3_mutex_free(p->mutex);
      if( p->mutexBuf ) sqlite3_mutex_free(p->mutexBuf);
      if( p->pMMapBuf ){
        UnmapViewOfFile(p->pMMapBuf);
      }
      if( INVALID_HANDLE_VALUE != p->hMap ){
        CloseHandle(p->hMap);
      }
      if( p->hFile.h != INVALID_HANDLE_VALUE ) {
        winClose((sqlite3_file *)&p->hFile);
      }
      *pp = p->pNext;
      sqlite3_free(p);
    }else{
      pp = &p->pNext;
    }
  }
}

/*
** Open a shared-memory area.  This particular implementation uses
** mmapped files.
**
** zName is a filename used to identify the shared-memory area.  The
** implementation does not (and perhaps should not) use this name
** directly, but rather use it as a template for finding an appropriate
** name for the shared-memory storage.  In this implementation, the
** string "-index" is appended to zName and used as the name of the
** mmapped file.
**
** When opening a new shared-memory file, if no other instances of that
** file are currently open, in this process or in other processes, then
** the file must be truncated to zero length or have its header cleared.
*/
static int winShmOpen(
  sqlite3_vfs *pVfs,    /* The VFS */
  const char *zName,    /* Name of the corresponding database file */
  sqlite3_shm **pShm    /* Write the winShm object created here */
){
  struct winShm *p;                  /* The connection to be opened */
  struct winShmFile *pFile = 0;      /* The underlying mmapped file */
  int rc;                            /* Result code */
  struct winShmFile *pNew;           /* Newly allocated pFile */
  int nName;                         /* Size of zName in bytes */
  char zFullpath[MAX_PATH+1];        /* Temp buffer for full file name */

  rc = winFullPathname(pVfs, zName, MAX_PATH, zFullpath);
  if( rc ) return rc;

  /* Allocate space for the new sqlite3_shm object.  Also speculatively
  ** allocate space for a new winShmFile and filename.
  */
  p = sqlite3_malloc( sizeof(*p) );
  if( p==0 ) return SQLITE_NOMEM;
  memset(p, 0, sizeof(*p));
  nName = sqlite3Strlen30(zFullpath);
  pNew = sqlite3_malloc( sizeof(*pFile) + nName + 15 );
  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_NOMEM;
  }
  memset(pNew, 0, sizeof(*pNew));
  pNew->zFilename = (char*)&pNew[1];
  sqlite3_snprintf(nName+12, pNew->zFilename, "%s-wal-index", zFullpath);

  /* Look to see if there is an existing winShmFile that can be used.
  ** If no matching winShmFile currently exists, create a new one.
  */
  winShmEnterMutex();
  for(pFile = winShmFileList; pFile; pFile=pFile->pNext){
    /* TBD need to come up with better match here.  Perhaps
    ** use FILE_ID_BOTH_DIR_INFO Structure.
    */
    if( sqlite3StrICmp(pFile->zFilename, pNew->zFilename)==0 ) break;
  }
  if( pFile ){
    sqlite3_free(pNew);
  }else{
    pFile = pNew;
    pNew = 0;
    pFile->pMMapBuf = NULL;
    pFile->hMap = INVALID_HANDLE_VALUE;
    ((winFile*)(&pFile->hFile))->h = INVALID_HANDLE_VALUE;
    pFile->pNext = winShmFileList;
    winShmFileList = pFile;

    pFile->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pFile->mutex==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    pFile->mutexBuf = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pFile->mutexBuf==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    rc = winOpen(pVfs,
                 pFile->zFilename,                  /* Name of the file (UTF-8) */
                 (sqlite3_file *)&pFile->hFile, /* Write the SQLite file handle here */
                 SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, /* Open mode flags */
                 0);
    if( SQLITE_OK!=rc ){
      rc = SQLITE_CANTOPEN_BKPT;
      goto shm_open_err;
    }

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    if( winShmSystemLock(pFile, _SHM_WRLCK, WIN_SHM_DMS)==SQLITE_OK ){
      rc = winTruncate((sqlite3_file *)&pFile->hFile, 0);
    }
    if( rc==SQLITE_OK ){
      rc = winShmSystemLock(pFile, _SHM_RDLCK, WIN_SHM_DMS);
    }
    if( rc ) goto shm_open_err;
  }

  /* Make the new connection a child of the winShmFile */
  p->pFile = pFile;
  p->pNext = pFile->pFirst;
#ifdef SQLITE_DEBUG
  p->id = pFile->nextShmId++;
#endif
  pFile->pFirst = p;
  pFile->nRef++;
  *pShm = (sqlite3_shm*)p;
  winShmLeaveMutex();
  return SQLITE_OK;

  /* Jump here on any error */
shm_open_err:
  winShmSystemLock(pFile, _SHM_UNLCK, WIN_SHM_DMS);
  winShmPurge();                 /* This call frees pFile if required */
  sqlite3_free(p);
  sqlite3_free(pNew);
  *pShm = 0;
  winShmLeaveMutex();
  return rc;
}

/*
** Close a connection to shared-memory.  Delete the underlying 
** storage if deleteFlag is true.
*/
static int winShmClose(
  sqlite3_vfs *pVfs,         /* The VFS */
  sqlite3_shm *pSharedMem,   /* The shared-memory to be closed */
  int deleteFlag             /* Delete after closing if true */
){
  winShm *p;            /* The connection to be closed */
  winShmFile *pFile;    /* The underlying shared-memory file */
  winShm **pp;          /* For looping over sibling connections */

  UNUSED_PARAMETER(pVfs);
  if( pSharedMem==0 ) return SQLITE_OK;
  p = (struct winShm*)pSharedMem;
  pFile = p->pFile;

  /* Verify that the connection being closed holds no locks */
  assert( p->exclMask==0 );
  assert( p->sharedMask==0 );

  /* Remove connection p from the set of connections associated with pFile */
  sqlite3_mutex_enter(pFile->mutex);
  for(pp=&pFile->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
  *pp = p->pNext;

  /* Free the connection p */
  sqlite3_free(p);
  sqlite3_mutex_leave(pFile->mutex);

  /* If pFile->nRef has reached 0, then close the underlying
  ** shared-memory file, too */
  winShmEnterMutex();
  assert( pFile->nRef>0 );
  pFile->nRef--;
  if( pFile->nRef==0 ){
    if( deleteFlag ) winDelete(pVfs, pFile->zFilename, 0);
    winShmPurge();
  }
  winShmLeaveMutex();

  return SQLITE_OK;
}

/*
** Query and/or changes the size of the underlying storage for
** a shared-memory segment.  The reqSize parameter is the new size
** of the underlying storage, or -1 to do just a query.  The size
** of the underlying storage (after resizing if resizing occurs) is
** written into pNewSize.
**
** This routine does not (necessarily) change the size of the mapping 
** of the underlying storage into memory.  Use xShmGet() to change
** the mapping size.
**
** The reqSize parameter is the minimum size requested.  The implementation
** is free to expand the storage to some larger amount if it chooses.
*/
static int winShmSize(
  sqlite3_vfs *pVfs,        /* The VFS */
  sqlite3_shm *pSharedMem,  /* Pointer returned by winShmOpen() */
  int reqSize,              /* Requested size.  -1 for query only */
  int *pNewSize             /* Write new size here */
){
  winShm *p = (winShm*)pSharedMem;
  winShmFile *pFile = p->pFile;
  int rc = SQLITE_OK;

  UNUSED_PARAMETER(pVfs);

  if( reqSize>=0 ){
    reqSize = (reqSize + SQLITE_WIN_SHM_INCR - 1)/SQLITE_WIN_SHM_INCR;
    reqSize *= SQLITE_WIN_SHM_INCR;
    rc = winTruncate((sqlite3_file *)&pFile->hFile, reqSize);
  }
  if( SQLITE_OK==rc ){
    sqlite3_int64 sz;
    rc = winFileSize((sqlite3_file *)&pFile->hFile, &sz);
    if( SQLITE_OK==rc ){
      *pNewSize = (int)sz;
    }else{
      *pNewSize = 0;
      rc = SQLITE_IOERR;
    }
  }
  return rc;
}


/*
** Map the shared storage into memory.  The minimum size of the
** mapping should be reqMapSize if reqMapSize is positive.  If
** reqMapSize is zero or negative, the implementation can choose
** whatever mapping size is convenient.
**
** *ppBuf is made to point to the memory which is a mapping of the
** underlying storage.  A mutex is acquired to prevent other threads
** from running while *ppBuf is in use in order to prevent other threads
** remapping *ppBuf out from under this thread.  The winShmRelease()
** call will release the mutex.  However, if the lock state is CHECKPOINT,
** the mutex is not acquired because CHECKPOINT will never remap the
** buffer.  RECOVER might remap, though, so CHECKPOINT will acquire
** the mutex if and when it promotes to RECOVER.
**
** RECOVER needs to be atomic.  The same mutex that prevents *ppBuf from
** being remapped also prevents more than one thread from being in
** RECOVER at a time.  But, RECOVER sometimes wants to remap itself.
** To prevent RECOVER from losing its lock while remapping, the
** mutex is not released by winShmRelease() when in RECOVER.
**
** *pNewMapSize is set to the size of the mapping.
**
** *ppBuf and *pNewMapSize might be NULL and zero if no space has
** yet been allocated to the underlying storage.
*/
static int winShmGet(
  sqlite3_vfs *pVfs,       /* The VFS */
  sqlite3_shm *pSharedMem, /* Pointer returned by winShmOpen() */
  int reqMapSize,          /* Requested size of mapping. -1 means don't care */
  int *pNewMapSize,        /* Write new size of mapping here */
  void **ppBuf             /* Write mapping buffer origin here */
){
  winShm *p = (winShm*)pSharedMem;
  winShmFile *pFile = p->pFile;
  int rc = SQLITE_OK;

  if( p->lockState!=SQLITE_SHM_CHECKPOINT && p->hasMutexBuf==0 ){
    assert( sqlite3_mutex_notheld(pFile->mutex) );
    sqlite3_mutex_enter(pFile->mutexBuf);
    p->hasMutexBuf = 1;
  }
  sqlite3_mutex_enter(pFile->mutex);
  if( pFile->szMap==0 || reqMapSize>pFile->szMap ){
    int actualSize;
    if( winShmSize(pVfs, pSharedMem, -1, &actualSize)==SQLITE_OK
     && reqMapSize<actualSize
    ){
      reqMapSize = actualSize;
    }
    if( pFile->pMMapBuf ){
      if( !UnmapViewOfFile(pFile->pMMapBuf) ){
        pFile->lastErrno = GetLastError();
        rc = SQLITE_IOERR;
      }
      CloseHandle(pFile->hMap);
      pFile->hMap = INVALID_HANDLE_VALUE;
    }
    if( SQLITE_OK == rc ){
      pFile->pMMapBuf = 0;
      if( reqMapSize == 0 ){
        /* can't create 0 byte file mapping in Windows */
        pFile->szMap = 0;
      }else{
        /* create the file mapping object */
        if( INVALID_HANDLE_VALUE == pFile->hMap ){
          /* TBD provide an object name to each file
          ** mapping so it can be re-used across processes.
          */
          pFile->hMap = CreateFileMapping(pFile->hFile.h,
                                          NULL,
                                          PAGE_READWRITE,
                                          0,
                                          reqMapSize,
                                          NULL);
        }
        if( NULL==pFile->hMap ){
          pFile->lastErrno = GetLastError();
          rc = SQLITE_IOERR;
          pFile->szMap = 0;
          pFile->hMap = INVALID_HANDLE_VALUE;
        }else{
          pFile->pMMapBuf = MapViewOfFile(pFile->hMap,
                                          FILE_MAP_WRITE | FILE_MAP_READ,
                                          0,
                                          0,
                                          reqMapSize);
          if( !pFile->pMMapBuf ){
            pFile->lastErrno = GetLastError();
            rc = SQLITE_IOERR;
            pFile->szMap = 0;
          }else{
            pFile->szMap = reqMapSize;
          }
        }
      }
    }
  }
  *pNewMapSize = pFile->szMap;
  *ppBuf = pFile->pMMapBuf;
  sqlite3_mutex_leave(pFile->mutex);
  return rc;
}

/*
** Release the lock held on the shared memory segment so that other
** threads are free to resize it if necessary.
**
** If the lock is not currently held, this routine is a harmless no-op.
**
** If the shared-memory object is in lock state RECOVER, then we do not
** really want to release the lock, so in that case too, this routine
** is a no-op.
*/
static int winShmRelease(sqlite3_vfs *pVfs, sqlite3_shm *pSharedMem){
  winShm *p = (winShm*)pSharedMem;
  UNUSED_PARAMETER(pVfs);
  if( p->hasMutexBuf && p->lockState!=SQLITE_SHM_RECOVER ){
    winShmFile *pFile = p->pFile;
    assert( sqlite3_mutex_notheld(pFile->mutex) );
    sqlite3_mutex_leave(pFile->mutexBuf);
    p->hasMutexBuf = 0;
  }
  return SQLITE_OK;
}

/*
** Symbolic names for LOCK states used for debugging.
*/
#ifdef SQLITE_DEBUG
static const char *azLkName[] = {
  "UNLOCK",
  "READ",
  "READ_FULL",
  "WRITE",
  "PENDING",
  "CHECKPOINT",
  "RECOVER"
};
#endif


/*
** Change the lock state for a shared-memory segment.
*/
static int winShmLock(
  sqlite3_vfs *pVfs,         /* The VFS */
  sqlite3_shm *pSharedMem,   /* Pointer from winShmOpen() */
  int desiredLock,           /* One of SQLITE_SHM_xxxxx locking states */
  int *pGotLock              /* The lock you actually got */
){
  winShm *p = (winShm*)pSharedMem;
  winShmFile *pFile = p->pFile;
  int rc = SQLITE_PROTOCOL;

  UNUSED_PARAMETER(pVfs);

  /* Note that SQLITE_SHM_READ_FULL and SQLITE_SHM_PENDING are never
  ** directly requested; they are side effects from requesting
  ** SQLITE_SHM_READ and SQLITE_SHM_CHECKPOINT, respectively.
  */
  assert( desiredLock==SQLITE_SHM_UNLOCK
       || desiredLock==SQLITE_SHM_READ
       || desiredLock==SQLITE_SHM_WRITE
       || desiredLock==SQLITE_SHM_CHECKPOINT
       || desiredLock==SQLITE_SHM_RECOVER );

  /* Return directly if this is just a lock state query, or if
  ** the connection is already in the desired locking state.
  */
  if( desiredLock==p->lockState
   || (desiredLock==SQLITE_SHM_READ && p->lockState==SQLITE_SHM_READ_FULL)
  ){
    OSTRACE(("SHM-LOCK %d shmid-%d, pid-%d request %s and got %s\n",
             pFile->hFile.h,
             p->id, (int)GetCurrentProcessId(), azLkName[desiredLock], azLkName[p->lockState]));
    if( pGotLock ) *pGotLock = p->lockState;
    return SQLITE_OK;
  }

  OSTRACE(("SHM-LOCK %d shmid-%d, pid-%d request %s->%s\n",
           pFile->hFile.h,
           p->id, (int)GetCurrentProcessId(), azLkName[p->lockState], azLkName[desiredLock]));
  
  if( desiredLock==SQLITE_SHM_RECOVER && !p->hasMutexBuf ){
    assert( sqlite3_mutex_notheld(pFile->mutex) );
    sqlite3_mutex_enter(pFile->mutexBuf);
    p->hasMutexBuf = 1;
  }
  sqlite3_mutex_enter(pFile->mutex);
  switch( desiredLock ){
    case SQLITE_SHM_UNLOCK: {
      assert( p->lockState!=SQLITE_SHM_RECOVER );
      winShmUnlock(pFile, p, WIN_SHM_A|WIN_SHM_B|WIN_SHM_C|WIN_SHM_D);
      rc = SQLITE_OK;
      p->lockState = SQLITE_SHM_UNLOCK;
      break;
    }
    case SQLITE_SHM_READ: {
      if( p->lockState==SQLITE_SHM_UNLOCK ){
        int nAttempt;
        rc = SQLITE_BUSY;
        assert( p->lockState==SQLITE_SHM_UNLOCK );
        for(nAttempt=0; nAttempt<5 && rc==SQLITE_BUSY; nAttempt++){
          rc = winShmSharedLock(pFile, p, WIN_SHM_A|WIN_SHM_B);
          if( rc==SQLITE_BUSY ){
            rc = winShmSharedLock(pFile, p, WIN_SHM_D);
            if( rc==SQLITE_OK ){
              p->lockState = SQLITE_SHM_READ_FULL;
            }
          }else{
            winShmUnlock(pFile, p, WIN_SHM_B);
            p->lockState = SQLITE_SHM_READ;
          }
        }
      }else{
       assert( p->lockState==SQLITE_SHM_WRITE
               || p->lockState==SQLITE_SHM_RECOVER );
        rc = winShmSharedLock(pFile, p, WIN_SHM_A);
        winShmUnlock(pFile, p, WIN_SHM_C|WIN_SHM_D);
        p->lockState = SQLITE_SHM_READ;
      }
      break;
    }
    case SQLITE_SHM_WRITE: {
      assert( p->lockState==SQLITE_SHM_READ 
              || p->lockState==SQLITE_SHM_READ_FULL );
      rc = winShmExclusiveLock(pFile, p, WIN_SHM_C|WIN_SHM_D);
      if( rc==SQLITE_OK ){
        p->lockState = SQLITE_SHM_WRITE;
      }
      break;
    }
    case SQLITE_SHM_CHECKPOINT: {
      assert( p->lockState==SQLITE_SHM_UNLOCK
           || p->lockState==SQLITE_SHM_PENDING
      );
      if( p->lockState==SQLITE_SHM_UNLOCK ){
        rc = winShmExclusiveLock(pFile, p, WIN_SHM_B|WIN_SHM_C);
        if( rc==SQLITE_OK ){
          p->lockState = SQLITE_SHM_PENDING;
        }
      }
      if( p->lockState==SQLITE_SHM_PENDING ){
        rc = winShmExclusiveLock(pFile, p, WIN_SHM_A);
        if( rc==SQLITE_OK ){
          p->lockState = SQLITE_SHM_CHECKPOINT;
        }
      }
      break;
    }
    default: {
      assert( desiredLock==SQLITE_SHM_RECOVER );
      assert( p->lockState==SQLITE_SHM_READ
           || p->lockState==SQLITE_SHM_READ_FULL
      );
      assert( sqlite3_mutex_held(pFile->mutexBuf) );
      rc = winShmExclusiveLock(pFile, p, WIN_SHM_C);
      if( rc==SQLITE_OK ){
        p->lockState = SQLITE_SHM_RECOVER;
      }
      break;
    }
  }
  sqlite3_mutex_leave(pFile->mutex);
  OSTRACE(("SHM-LOCK %d shmid-%d, pid-%d got %s\n",
           pFile->hFile.h, 
           p->id, (int)GetCurrentProcessId(), azLkName[p->lockState]));
  if( pGotLock ) *pGotLock = p->lockState;
  return rc;
}

#else
# define winShmOpen    0
# define winShmSize    0
# define winShmGet     0
# define winShmRelease 0
# define winShmLock    0
# define winShmClose   0
#endif /* #ifndef SQLITE_OMIT_WAL */


/*
** Initialize and deinitialize the operating system interface.
*/
int sqlite3_os_init(void){
  static sqlite3_vfs winVfs = {







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** sqlite3_errmsg(), possibly making IO errors easier to debug.
*/
static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
  UNUSED_PARAMETER(pVfs);
  return getLastErrorMsg(nBuf, zBuf);
}































































































































































































































































































































































































































































































































































































































































































































































































































































































































































/*
** Initialize and deinitialize the operating system interface.
*/
int sqlite3_os_init(void){
  static sqlite3_vfs winVfs = {
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    winDlError,          /* xDlError */
    winDlSym,            /* xDlSym */
    winDlClose,          /* xDlClose */
    winRandomness,       /* xRandomness */
    winSleep,            /* xSleep */
    winCurrentTime,      /* xCurrentTime */
    winGetLastError,     /* xGetLastError */
    winShmOpen,          /* xShmOpen */
    winShmSize,          /* xShmSize */
    winShmGet,           /* xShmGet */
    winShmRelease,       /* xShmRelease */
    winShmLock,          /* xShmLock */
    winShmClose,         /* xShmClose */
    0,                   /* xRename */
    winCurrentTimeInt64, /* xCurrentTimeInt64 */
  };

  sqlite3_vfs_register(&winVfs, 1);
  return SQLITE_OK; 
}
int sqlite3_os_end(void){ 
  return SQLITE_OK;
}

#endif /* SQLITE_OS_WIN */







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    winDlError,          /* xDlError */
    winDlSym,            /* xDlSym */
    winDlClose,          /* xDlClose */
    winRandomness,       /* xRandomness */
    winSleep,            /* xSleep */
    winCurrentTime,      /* xCurrentTime */
    winGetLastError,     /* xGetLastError */






    0,                   /* xRename */
    winCurrentTimeInt64, /* xCurrentTimeInt64 */
  };

  sqlite3_vfs_register(&winVfs, 1);
  return SQLITE_OK; 
}
int sqlite3_os_end(void){ 
  return SQLITE_OK;
}

#endif /* SQLITE_OS_WIN */
Changes to src/pager.c.
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      if( pPager->journalOff==0 ){
        rc = SQLITE_OK;
      }else{
        rc = sqlite3OsTruncate(pPager->jfd, 0);
      }
      pPager->journalOff = 0;
      pPager->journalStarted = 0;
    }else if( pPager->exclusiveMode 
     || pPager->journalMode==PAGER_JOURNALMODE_PERSIST
    ){
      rc = zeroJournalHdr(pPager, hasMaster);
      pager_error(pPager, rc);
      pPager->journalOff = 0;
      pPager->journalStarted = 0;
    }else{
      /* This branch may be executed with Pager.journalMode==MEMORY if







|
|







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      if( pPager->journalOff==0 ){
        rc = SQLITE_OK;
      }else{
        rc = sqlite3OsTruncate(pPager->jfd, 0);
      }
      pPager->journalOff = 0;
      pPager->journalStarted = 0;
    }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
      || (pPager->exclusiveMode && pPager->journalMode!=PAGER_JOURNALMODE_WAL)
    ){
      rc = zeroJournalHdr(pPager, hasMaster);
      pager_error(pPager, rc);
      pPager->journalOff = 0;
      pPager->journalStarted = 0;
    }else{
      /* This branch may be executed with Pager.journalMode==MEMORY if
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1441











1442
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  pPager->pInJournal = 0;
  pPager->nRec = 0;
  sqlite3PcacheCleanAll(pPager->pPCache);

  if( pagerUseWal(pPager) ){
    rc2 = sqlite3WalWriteLock(pPager->pWal, 0);
    pPager->state = PAGER_SHARED;











  }else if( !pPager->exclusiveMode ){
    rc2 = osUnlock(pPager->fd, SHARED_LOCK);
    pPager->state = PAGER_SHARED;
    pPager->changeCountDone = 0;
  }else if( pPager->state==PAGER_SYNCED ){
    pPager->state = PAGER_EXCLUSIVE;
  }







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>







1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
  pPager->pInJournal = 0;
  pPager->nRec = 0;
  sqlite3PcacheCleanAll(pPager->pPCache);

  if( pagerUseWal(pPager) ){
    rc2 = sqlite3WalWriteLock(pPager->pWal, 0);
    pPager->state = PAGER_SHARED;

    /* If the connection was in locking_mode=exclusive mode but is no longer,
    ** drop the EXCLUSIVE lock held on the database file.
    */
    if( rc2==SQLITE_OK 
     && !pPager->exclusiveMode 
     && sqlite3WalExclusiveMode(pPager->pWal, -1) 
    ){
      sqlite3WalExclusiveMode(pPager->pWal, 0);
      rc2 = osUnlock(pPager->fd, SHARED_LOCK);
    }
  }else if( !pPager->exclusiveMode ){
    rc2 = osUnlock(pPager->fd, SHARED_LOCK);
    pPager->state = PAGER_SHARED;
    pPager->changeCountDone = 0;
  }else if( pPager->state==PAGER_SYNCED ){
    pPager->state = PAGER_EXCLUSIVE;
  }
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
  u8 *pTmp = (u8 *)pPager->pTmpSpace;

  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  pPager->errCode = 0;
  pPager->exclusiveMode = 0;
#ifndef SQLITE_OMIT_WAL
  sqlite3WalClose(pPager->pWal, pPager->fd, 
    (pPager->noSync ? 0 : pPager->sync_flags), 
    pPager->pageSize, pTmp
  );
  pPager->pWal = 0;
#endif
  pager_reset(pPager);
  if( MEMDB ){







|







3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
  u8 *pTmp = (u8 *)pPager->pTmpSpace;

  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  pPager->errCode = 0;
  pPager->exclusiveMode = 0;
#ifndef SQLITE_OMIT_WAL
  sqlite3WalClose(pPager->pWal,
    (pPager->noSync ? 0 : pPager->sync_flags), 
    pPager->pageSize, pTmp
  );
  pPager->pWal = 0;
#endif
  pager_reset(pPager);
  if( MEMDB ){
4505
4506
4507
4508
4509
4510
4511

4512
4513
4514
4515
4516












4517
4518
4519
4520






4521
4522
4523
4524
4525
4526
4527



4528
4529
4530
4531
4532
4533
4534
** sub-journal is implemented in-memory if pPager is an in-memory database, 
** or using a temporary file otherwise.
*/
int sqlite3PagerBegin(Pager *pPager, int exFlag, int subjInMemory){
  int rc = SQLITE_OK;
  assert( pPager->state!=PAGER_UNLOCK );
  pPager->subjInMemory = (u8)subjInMemory;

  if( pPager->state==PAGER_SHARED ){
    assert( pPager->pInJournal==0 );
    assert( !MEMDB && !pPager->tempFile );

    if( pagerUseWal(pPager) ){












      /* Grab the write lock on the log file. If successful, upgrade to
      ** PAGER_EXCLUSIVE state. Otherwise, return an error code to the caller.
      ** The busy-handler is not invoked if another connection already
      ** holds the write-lock. If possible, the upper layer will call it.






      */
      rc = sqlite3WalWriteLock(pPager->pWal, 1);
      if( rc==SQLITE_OK ){
        pPager->dbOrigSize = pPager->dbSize;
        pPager->state = PAGER_RESERVED;
        pPager->journalOff = 0;
      }



    }else{
      /* Obtain a RESERVED lock on the database file. If the exFlag parameter
      ** is true, then immediately upgrade this to an EXCLUSIVE lock. The
      ** busy-handler callback can be used when upgrading to the EXCLUSIVE
      ** lock, but not when obtaining the RESERVED lock.
      */
      rc = sqlite3OsLock(pPager->fd, RESERVED_LOCK);







>





>
>
>
>
>
>
>
>
>
>
>
>

|


>
>
>
>
>
>







>
>
>







4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
** sub-journal is implemented in-memory if pPager is an in-memory database, 
** or using a temporary file otherwise.
*/
int sqlite3PagerBegin(Pager *pPager, int exFlag, int subjInMemory){
  int rc = SQLITE_OK;
  assert( pPager->state!=PAGER_UNLOCK );
  pPager->subjInMemory = (u8)subjInMemory;

  if( pPager->state==PAGER_SHARED ){
    assert( pPager->pInJournal==0 );
    assert( !MEMDB && !pPager->tempFile );

    if( pagerUseWal(pPager) ){
      /* If the pager is configured to use locking_mode=exclusive, and an
      ** exclusive lock on the database is not already held, obtain it now.
      */
      if( pPager->exclusiveMode && !sqlite3WalExclusiveMode(pPager->pWal, -1) ){
        rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
        pPager->state = PAGER_SHARED;
        if( rc!=SQLITE_OK ){
          return rc;
        }
        sqlite3WalExclusiveMode(pPager->pWal, 1);
      }

      /* Grab the write lock on the log file. If successful, upgrade to
      ** PAGER_RESERVED state. Otherwise, return an error code to the caller.
      ** The busy-handler is not invoked if another connection already
      ** holds the write-lock. If possible, the upper layer will call it.
      **
      ** WAL mode sets Pager.state to PAGER_RESERVED when it has an open
      ** transaction, but never to PAGER_EXCLUSIVE. This is because in 
      ** PAGER_EXCLUSIVE state the code to roll back savepoint transactions
      ** may copy data from the sub-journal into the database file as well
      ** as into the page cache. Which would be incorrect in WAL mode.
      */
      rc = sqlite3WalWriteLock(pPager->pWal, 1);
      if( rc==SQLITE_OK ){
        pPager->dbOrigSize = pPager->dbSize;
        pPager->state = PAGER_RESERVED;
        pPager->journalOff = 0;
      }

      assert( rc!=SQLITE_OK || pPager->state==PAGER_RESERVED );
      assert( rc==SQLITE_OK || pPager->state==PAGER_SHARED );
    }else{
      /* Obtain a RESERVED lock on the database file. If the exFlag parameter
      ** is true, then immediately upgrade this to an EXCLUSIVE lock. The
      ** busy-handler callback can be used when upgrading to the EXCLUSIVE
      ** lock, but not when obtaining the RESERVED lock.
      */
      rc = sqlite3OsLock(pPager->fd, RESERVED_LOCK);
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859









5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872

5873
5874
5875
5876
5877
5878

5879
5880
5881
5882
5883
5884
5885
/*
** This function is called when the user invokes "PRAGMA checkpoint".
*/
int sqlite3PagerCheckpoint(Pager *pPager){
  int rc = SQLITE_OK;
  if( pPager->pWal ){
    u8 *zBuf = (u8 *)pPager->pTmpSpace;
    rc = sqlite3WalCheckpoint(pPager->pWal, pPager->fd, 
        (pPager->noSync ? 0 : pPager->sync_flags),
        pPager->pageSize, zBuf, 
        pPager->xBusyHandler, pPager->pBusyHandlerArg
    );
  }
  return rc;
}

int sqlite3PagerWalCallback(Pager *pPager){
  return sqlite3WalCallback(pPager->pWal);
}










/*
** Open a connection to the write-ahead log file for pager pPager. If
** the log connection is already open, this function is a no-op.
**
** The caller must be holding a SHARED lock on the database file to call
** this function.
*/
int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen){
  int rc = SQLITE_OK;             /* Return code */

  assert( pPager->state>=PAGER_SHARED );
  if( !pPager->pWal ){


    /* Open the connection to the log file. If this operation fails, 
    ** (e.g. due to malloc() failure), unlock the database file and 
    ** return an error code.
    */
    rc = sqlite3WalOpen(pPager->pVfs, pPager->zFilename, &pPager->pWal);

    if( rc==SQLITE_OK ){
      pPager->journalMode = PAGER_JOURNALMODE_WAL;
    }
  }else{
    *pisOpen = 1;
  }








|











>
>
>
>
>
>
>
>
>













>





|
>







5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
/*
** This function is called when the user invokes "PRAGMA checkpoint".
*/
int sqlite3PagerCheckpoint(Pager *pPager){
  int rc = SQLITE_OK;
  if( pPager->pWal ){
    u8 *zBuf = (u8 *)pPager->pTmpSpace;
    rc = sqlite3WalCheckpoint(pPager->pWal,
        (pPager->noSync ? 0 : pPager->sync_flags),
        pPager->pageSize, zBuf, 
        pPager->xBusyHandler, pPager->pBusyHandlerArg
    );
  }
  return rc;
}

int sqlite3PagerWalCallback(Pager *pPager){
  return sqlite3WalCallback(pPager->pWal);
}

/*
** Return true if the underlying VFS for the given pager supports the
** primitives necessary for write-ahead logging.
*/
int sqlite3PagerWalSupported(Pager *pPager){
  const sqlite3_io_methods *pMethods = pPager->fd->pMethods;
  return pMethods->iVersion>=2 && pMethods->xShmOpen!=0;
}

/*
** Open a connection to the write-ahead log file for pager pPager. If
** the log connection is already open, this function is a no-op.
**
** The caller must be holding a SHARED lock on the database file to call
** this function.
*/
int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen){
  int rc = SQLITE_OK;             /* Return code */

  assert( pPager->state>=PAGER_SHARED );
  if( !pPager->pWal ){
    if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;

    /* Open the connection to the log file. If this operation fails, 
    ** (e.g. due to malloc() failure), unlock the database file and 
    ** return an error code.
    */
    rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
                        pPager->zFilename, &pPager->pWal);
    if( rc==SQLITE_OK ){
      pPager->journalMode = PAGER_JOURNALMODE_WAL;
    }
  }else{
    *pisOpen = 1;
  }

5907
5908
5909
5910
5911
5912
5913
5914

5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928




5929
5930
5931
5932
5933
5934
5935
  if( !pPager->pWal ){
    int logexists = 0;
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_SHARED);
    if( rc==SQLITE_OK ){
      rc = pagerHasWAL(pPager, &logexists);
    }
    if( rc==SQLITE_OK && logexists ){
      rc = sqlite3WalOpen(pPager->pVfs, pPager->zFilename, &pPager->pWal);

    }
  }
    
  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
  ** the database file, the log and log-summary files will be deleted.
  */
  if( rc==SQLITE_OK && pPager->pWal ){
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_EXCLUSIVE);
    if( rc==SQLITE_OK ){
      rc = sqlite3WalClose(pPager->pWal, pPager->fd,
        (pPager->noSync ? 0 : pPager->sync_flags), 
        pPager->pageSize, (u8*)pPager->pTmpSpace
      );
      pPager->pWal = 0;




    }
  }
  return rc;
}
#endif

#endif /* SQLITE_OMIT_DISKIO */







|
>









|
|



>
>
>
>







5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
  if( !pPager->pWal ){
    int logexists = 0;
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_SHARED);
    if( rc==SQLITE_OK ){
      rc = pagerHasWAL(pPager, &logexists);
    }
    if( rc==SQLITE_OK && logexists ){
      rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
                          pPager->zFilename, &pPager->pWal);
    }
  }
    
  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
  ** the database file, the log and log-summary files will be deleted.
  */
  if( rc==SQLITE_OK && pPager->pWal ){
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_EXCLUSIVE);
    if( rc==SQLITE_OK ){
      rc = sqlite3WalClose(pPager->pWal,
                           (pPager->noSync ? 0 : pPager->sync_flags), 
        pPager->pageSize, (u8*)pPager->pTmpSpace
      );
      pPager->pWal = 0;
    }else{
      /* If we cannot get an EXCLUSIVE lock, downgrade the PENDING lock
      ** that we did get back to SHARED. */
      sqlite3OsUnlock(pPager->fd, SQLITE_LOCK_SHARED);
    }
  }
  return rc;
}
#endif

#endif /* SQLITE_OMIT_DISKIO */
Changes to src/pager.h.
131
132
133
134
135
136
137

138
139
140
141
142
143
144
int sqlite3PagerCommitPhaseTwo(Pager*);
int sqlite3PagerRollback(Pager*);
int sqlite3PagerOpenSavepoint(Pager *pPager, int n);
int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);
int sqlite3PagerSharedLock(Pager *pPager);

int sqlite3PagerCheckpoint(Pager *pPager);

int sqlite3PagerWalCallback(Pager *pPager);
int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
int sqlite3PagerCloseWal(Pager *pPager);

/* Functions used to query pager state and configuration. */
u8 sqlite3PagerIsreadonly(Pager*);
int sqlite3PagerRefcount(Pager*);







>







131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
int sqlite3PagerCommitPhaseTwo(Pager*);
int sqlite3PagerRollback(Pager*);
int sqlite3PagerOpenSavepoint(Pager *pPager, int n);
int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);
int sqlite3PagerSharedLock(Pager *pPager);

int sqlite3PagerCheckpoint(Pager *pPager);
int sqlite3PagerWalSupported(Pager *pPager);
int sqlite3PagerWalCallback(Pager *pPager);
int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
int sqlite3PagerCloseWal(Pager *pPager);

/* Functions used to query pager state and configuration. */
u8 sqlite3PagerIsreadonly(Pager*);
int sqlite3PagerRefcount(Pager*);
Changes to src/sqlite.h.in.
649
650
651
652
653
654
655








656
657
658
659
660
661
662
  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
  int (*xLock)(sqlite3_file*, int);
  int (*xUnlock)(sqlite3_file*, int);
  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
  int (*xSectorSize)(sqlite3_file*);
  int (*xDeviceCharacteristics)(sqlite3_file*);








  /* Additional methods may be added in future releases */
};

/*
** CAPI3REF: Standard File Control Opcodes
**
** These integer constants are opcodes for the xFileControl method







>
>
>
>
>
>
>
>







649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
  int (*xLock)(sqlite3_file*, int);
  int (*xUnlock)(sqlite3_file*, int);
  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
  int (*xSectorSize)(sqlite3_file*);
  int (*xDeviceCharacteristics)(sqlite3_file*);
  /* Methods above are valid for version 1 */
  int (*xShmOpen)(sqlite3_file*);
  int (*xShmSize)(sqlite3_file*, int reqSize, int *pNewSize);
  int (*xShmGet)(sqlite3_file*, int reqSize, int *pSize, void**);
  int (*xShmRelease)(sqlite3_file*);
  int (*xShmLock)(sqlite3_file*, int desiredLock, int *gotLock);
  int (*xShmClose)(sqlite3_file*, int deleteFlag);
  /* Methods above are valid for version 2 */
  /* Additional methods may be added in future releases */
};

/*
** CAPI3REF: Standard File Control Opcodes
**
** These integer constants are opcodes for the xFileControl method
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
** the actual number of bytes of randomness obtained.
** The xSleep() method causes the calling thread to sleep for at
** least the number of microseconds given.  The xCurrentTime()
** method returns a Julian Day Number for the current date and time.
**
*/
typedef struct sqlite3_vfs sqlite3_vfs;
typedef struct sqlite3_shm sqlite3_shm;
struct sqlite3_vfs {
  int iVersion;            /* Structure version number (currently 2) */
  int szOsFile;            /* Size of subclassed sqlite3_file */
  int mxPathname;          /* Maximum file pathname length */
  sqlite3_vfs *pNext;      /* Next registered VFS */
  const char *zName;       /* Name of this virtual file system */
  void *pAppData;          /* Pointer to application-specific data */







<







822
823
824
825
826
827
828

829
830
831
832
833
834
835
** the actual number of bytes of randomness obtained.
** The xSleep() method causes the calling thread to sleep for at
** least the number of microseconds given.  The xCurrentTime()
** method returns a Julian Day Number for the current date and time.
**
*/
typedef struct sqlite3_vfs sqlite3_vfs;

struct sqlite3_vfs {
  int iVersion;            /* Structure version number (currently 2) */
  int szOsFile;            /* Size of subclassed sqlite3_file */
  int mxPathname;          /* Maximum file pathname length */
  sqlite3_vfs *pNext;      /* Next registered VFS */
  const char *zName;       /* Name of this virtual file system */
  void *pAppData;          /* Pointer to application-specific data */
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
  int (*xSleep)(sqlite3_vfs*, int microseconds);
  int (*xCurrentTime)(sqlite3_vfs*, double*);
  int (*xGetLastError)(sqlite3_vfs*, int, char *);
  /*
  ** The methods above are in version 1 of the sqlite_vfs object
  ** definition.  Those that follow are added in version 2 or later
  */
  int (*xShmOpen)(sqlite3_vfs*, const char *zName, sqlite3_shm**);
  int (*xShmSize)(sqlite3_vfs*, sqlite3_shm*, int reqSize, int *pNewSize);
  int (*xShmGet)(sqlite3_vfs*, sqlite3_shm*, int reqSize, int *pSize, void**);
  int (*xShmRelease)(sqlite3_vfs*, sqlite3_shm*);
  int (*xShmLock)(sqlite3_vfs*, sqlite3_shm*, int desiredLock, int *gotLock);
  int (*xShmClose)(sqlite3_vfs*, sqlite3_shm*, int deleteFlag);
  int (*xRename)(sqlite3_vfs*, const char *zOld, const char *zNew, int dirSync);
  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
  /*
  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
  ** New fields may be appended in figure versions.  The iVersion
  ** value will increment whenever this happens. 
  */







<
<
<
<
<
<







846
847
848
849
850
851
852






853
854
855
856
857
858
859
  int (*xSleep)(sqlite3_vfs*, int microseconds);
  int (*xCurrentTime)(sqlite3_vfs*, double*);
  int (*xGetLastError)(sqlite3_vfs*, int, char *);
  /*
  ** The methods above are in version 1 of the sqlite_vfs object
  ** definition.  Those that follow are added in version 2 or later
  */






  int (*xRename)(sqlite3_vfs*, const char *zOld, const char *zNew, int dirSync);
  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
  /*
  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
  ** New fields may be appended in figure versions.  The iVersion
  ** value will increment whenever this happens. 
  */
Changes to src/test1.c.
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
  extern int sqlite3_sync_count, sqlite3_fullsync_count;
  extern int sqlite3_opentemp_count;
  extern int sqlite3_like_count;
  extern int sqlite3_xferopt_count;
  extern int sqlite3_pager_readdb_count;
  extern int sqlite3_pager_writedb_count;
  extern int sqlite3_pager_writej_count;
#if defined(__linux__) && defined(SQLITE_TEST) && SQLITE_THREADSAFE
  extern int threadsOverrideEachOthersLocks;
#endif
#if SQLITE_OS_WIN
  extern int sqlite3_os_type;
#endif
#ifdef SQLITE_DEBUG
  extern int sqlite3WhereTrace;
  extern int sqlite3OSTrace;
  extern int sqlite3VdbeAddopTrace;







<
<
<







5125
5126
5127
5128
5129
5130
5131



5132
5133
5134
5135
5136
5137
5138
  extern int sqlite3_sync_count, sqlite3_fullsync_count;
  extern int sqlite3_opentemp_count;
  extern int sqlite3_like_count;
  extern int sqlite3_xferopt_count;
  extern int sqlite3_pager_readdb_count;
  extern int sqlite3_pager_writedb_count;
  extern int sqlite3_pager_writej_count;



#if SQLITE_OS_WIN
  extern int sqlite3_os_type;
#endif
#ifdef SQLITE_DEBUG
  extern int sqlite3WhereTrace;
  extern int sqlite3OSTrace;
  extern int sqlite3VdbeAddopTrace;
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      (char*)&sqlite3_pager_writedb_count, TCL_LINK_INT);
  Tcl_LinkVar(interp, "sqlite3_pager_writej_count",
      (char*)&sqlite3_pager_writej_count, TCL_LINK_INT);
#ifndef SQLITE_OMIT_UTF16
  Tcl_LinkVar(interp, "unaligned_string_counter",
      (char*)&unaligned_string_counter, TCL_LINK_INT);
#endif
#if defined(__linux__) && defined(SQLITE_TEST) && SQLITE_THREADSAFE
  Tcl_LinkVar(interp, "threadsOverrideEachOthersLocks",
      (char*)&threadsOverrideEachOthersLocks, TCL_LINK_INT);
#endif
#ifndef SQLITE_OMIT_UTF16
  Tcl_LinkVar(interp, "sqlite_last_needed_collation",
      (char*)&pzNeededCollation, TCL_LINK_STRING|TCL_LINK_READ_ONLY);
#endif
#if SQLITE_OS_WIN
  Tcl_LinkVar(interp, "sqlite_os_type",
      (char*)&sqlite3_os_type, TCL_LINK_INT);







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      (char*)&sqlite3_pager_writedb_count, TCL_LINK_INT);
  Tcl_LinkVar(interp, "sqlite3_pager_writej_count",
      (char*)&sqlite3_pager_writej_count, TCL_LINK_INT);
#ifndef SQLITE_OMIT_UTF16
  Tcl_LinkVar(interp, "unaligned_string_counter",
      (char*)&unaligned_string_counter, TCL_LINK_INT);
#endif




#ifndef SQLITE_OMIT_UTF16
  Tcl_LinkVar(interp, "sqlite_last_needed_collation",
      (char*)&pzNeededCollation, TCL_LINK_STRING|TCL_LINK_READ_ONLY);
#endif
#if SQLITE_OS_WIN
  Tcl_LinkVar(interp, "sqlite_os_type",
      (char*)&sqlite3_os_type, TCL_LINK_INT);
Changes to src/test6.c.
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*/
static int cfSectorSize(sqlite3_file *pFile){
  return g.iSectorSize;
}
static int cfDeviceCharacteristics(sqlite3_file *pFile){
  return g.iDeviceCharacteristics;
}
























static const sqlite3_io_methods CrashFileVtab = {
  1,                            /* iVersion */
  cfClose,                      /* xClose */
  cfRead,                       /* xRead */
  cfWrite,                      /* xWrite */
  cfTruncate,                   /* xTruncate */
  cfSync,                       /* xSync */
  cfFileSize,                   /* xFileSize */
  cfLock,                       /* xLock */
  cfUnlock,                     /* xUnlock */
  cfCheckReservedLock,          /* xCheckReservedLock */
  cfFileControl,                /* xFileControl */
  cfSectorSize,                 /* xSectorSize */
  cfDeviceCharacteristics       /* xDeviceCharacteristics */






};

/*
** Application data for the crash VFS
*/
struct crashAppData {
  sqlite3_vfs *pOrig;                   /* Wrapped vfs structure */








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*/
static int cfSectorSize(sqlite3_file *pFile){
  return g.iSectorSize;
}
static int cfDeviceCharacteristics(sqlite3_file *pFile){
  return g.iDeviceCharacteristics;
}

/*
** Pass-throughs for WAL support.
*/
static int cfShmOpen(sqlite3_file *pFile){
  return sqlite3OsShmOpen(((CrashFile*)pFile)->pRealFile);
}
static int cfShmSize(sqlite3_file *pFile, int reqSize, int *pNew){
  return sqlite3OsShmSize(((CrashFile*)pFile)->pRealFile, reqSize, pNew);
}
static int cfShmGet(sqlite3_file *pFile, int reqSize, int *pSize, void **pp){
  return sqlite3OsShmGet(((CrashFile*)pFile)->pRealFile, reqSize, pSize, pp);
}
static int cfShmRelease(sqlite3_file *pFile){
  return sqlite3OsShmRelease(((CrashFile*)pFile)->pRealFile);
}
static int cfShmLock(sqlite3_file *pFile, int desired, int *pGot){
  return sqlite3OsShmLock(((CrashFile*)pFile)->pRealFile, desired, pGot);
}
static int cfShmClose(sqlite3_file *pFile, int delFlag){
  return sqlite3OsShmClose(((CrashFile*)pFile)->pRealFile, delFlag);
}


static const sqlite3_io_methods CrashFileVtab = {
  2,                            /* iVersion */
  cfClose,                      /* xClose */
  cfRead,                       /* xRead */
  cfWrite,                      /* xWrite */
  cfTruncate,                   /* xTruncate */
  cfSync,                       /* xSync */
  cfFileSize,                   /* xFileSize */
  cfLock,                       /* xLock */
  cfUnlock,                     /* xUnlock */
  cfCheckReservedLock,          /* xCheckReservedLock */
  cfFileControl,                /* xFileControl */
  cfSectorSize,                 /* xSectorSize */
  cfDeviceCharacteristics,      /* xDeviceCharacteristics */
  cfShmOpen,                    /* xShmOpen */
  cfShmSize,                    /* xShmSize */
  cfShmGet,                     /* xShmGet */
  cfShmRelease,                 /* xShmRelease */
  cfShmLock,                    /* xShmLock */
  cfShmClose                    /* xShmClose */
};

/*
** Application data for the crash VFS
*/
struct crashAppData {
  sqlite3_vfs *pOrig;                   /* Wrapped vfs structure */
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  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xSleep(pVfs, nMicro);
}
static int cfCurrentTime(sqlite3_vfs *pCfVfs, double *pTimeOut){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xCurrentTime(pVfs, pTimeOut);
}
static int cfShmOpen(sqlite3_vfs *pCfVfs, const char *zName, sqlite3_shm **pp){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xShmOpen(pVfs, zName, pp);
}
static int cfShmSize(sqlite3_vfs *pCfVfs, sqlite3_shm *p,
                     int reqSize, int *pNew){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xShmSize(pVfs, p, reqSize, pNew);
}
static int cfShmGet(sqlite3_vfs *pCfVfs, sqlite3_shm *p,
                    int reqSize, int *pSize, void **pp){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xShmGet(pVfs, p, reqSize, pSize, pp);
}
static int cfShmRelease(sqlite3_vfs *pCfVfs, sqlite3_shm *p){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xShmRelease(pVfs, p);
}
static int cfShmLock(sqlite3_vfs *pCfVfs, sqlite3_shm *p,
                     int desiredLock, int *gotLock){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xShmLock(pVfs, p, desiredLock, gotLock);
}
static int cfShmClose(sqlite3_vfs *pCfVfs, sqlite3_shm *p, int delFlag){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xShmClose(pVfs, p, delFlag);
}

static int processDevSymArgs(
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[],
  int *piDeviceChar,
  int *piSectorSize







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  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xSleep(pVfs, nMicro);
}
static int cfCurrentTime(sqlite3_vfs *pCfVfs, double *pTimeOut){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xCurrentTime(pVfs, pTimeOut);
}




























static int processDevSymArgs(
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[],
  int *piDeviceChar,
  int *piSectorSize
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    cfDlError,            /* xDlError */
    cfDlSym,              /* xDlSym */
    cfDlClose,            /* xDlClose */
    cfRandomness,         /* xRandomness */
    cfSleep,              /* xSleep */
    cfCurrentTime,        /* xCurrentTime */
    0,                    /* xGetlastError */
    cfShmOpen,            /* xShmOpen */
    cfShmSize,            /* xShmSize */
    cfShmGet,             /* xShmGet */
    cfShmRelease,         /* xShmRelease */
    cfShmLock,            /* xShmLock */
    cfShmClose,           /* xShmClose */
    0,                    /* xRename */
    0,                    /* xCurrentTimeInt64 */
  };

  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "ENABLE");
    return TCL_ERROR;







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    cfDlError,            /* xDlError */
    cfDlSym,              /* xDlSym */
    cfDlClose,            /* xDlClose */
    cfRandomness,         /* xRandomness */
    cfSleep,              /* xSleep */
    cfCurrentTime,        /* xCurrentTime */
    0,                    /* xGetlastError */






    0,                    /* xRename */
    0,                    /* xCurrentTimeInt64 */
  };

  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "ENABLE");
    return TCL_ERROR;
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  }

  if( crashVfs.pAppData==0 ){
    sqlite3_vfs *pOriginalVfs = sqlite3_vfs_find(0);
    crashVfs.mxPathname = pOriginalVfs->mxPathname;
    crashVfs.pAppData = (void *)pOriginalVfs;
    crashVfs.szOsFile = sizeof(CrashFile) + pOriginalVfs->szOsFile;
    if( pOriginalVfs->iVersion<2 || pOriginalVfs->xShmOpen==0 ){
      crashVfs.xShmOpen = 0;
    }else{
      crashVfs.xShmOpen = cfShmOpen;
    }
    sqlite3_vfs_register(&crashVfs, 0);
  }else{
    crashVfs.pAppData = 0;
    sqlite3_vfs_unregister(&crashVfs);
  }

  return TCL_OK;







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  }

  if( crashVfs.pAppData==0 ){
    sqlite3_vfs *pOriginalVfs = sqlite3_vfs_find(0);
    crashVfs.mxPathname = pOriginalVfs->mxPathname;
    crashVfs.pAppData = (void *)pOriginalVfs;
    crashVfs.szOsFile = sizeof(CrashFile) + pOriginalVfs->szOsFile;





    sqlite3_vfs_register(&crashVfs, 0);
  }else{
    crashVfs.pAppData = 0;
    sqlite3_vfs_unregister(&crashVfs);
  }

  return TCL_OK;
Changes to src/test_devsym.c.
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static int devsymFileSize(sqlite3_file*, sqlite3_int64 *pSize);
static int devsymLock(sqlite3_file*, int);
static int devsymUnlock(sqlite3_file*, int);
static int devsymCheckReservedLock(sqlite3_file*, int *);
static int devsymFileControl(sqlite3_file*, int op, void *pArg);
static int devsymSectorSize(sqlite3_file*);
static int devsymDeviceCharacteristics(sqlite3_file*);







/*
** Method declarations for devsym_vfs.
*/
static int devsymOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
static int devsymDelete(sqlite3_vfs*, const char *zName, int syncDir);
static int devsymAccess(sqlite3_vfs*, const char *zName, int flags, int *);
static int devsymFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
#ifndef SQLITE_OMIT_LOAD_EXTENSION
static void *devsymDlOpen(sqlite3_vfs*, const char *zFilename);
static void devsymDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
static void (*devsymDlSym(sqlite3_vfs*,void*, const char *zSymbol))(void);
static void devsymDlClose(sqlite3_vfs*, void*);
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
static int devsymRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int devsymSleep(sqlite3_vfs*, int microseconds);
static int devsymCurrentTime(sqlite3_vfs*, double*);

static int devsymShmOpen(sqlite3_vfs *, const char *, sqlite3_shm **);
static int devsymShmSize(sqlite3_vfs*, sqlite3_shm *, int , int *);
static int devsymShmGet(sqlite3_vfs*, sqlite3_shm *, int , int *, void **);
static int devsymShmRelease(sqlite3_vfs*, sqlite3_shm *);
static int devsymShmLock(sqlite3_vfs*, sqlite3_shm *, int , int *);
static int devsymShmClose(sqlite3_vfs*, sqlite3_shm *, int);

static sqlite3_vfs devsym_vfs = {
  2,                     /* iVersion */
  sizeof(devsym_file),      /* szOsFile */
  DEVSYM_MAX_PATHNAME,      /* mxPathname */
  0,                     /* pNext */
  DEVSYM_VFS_NAME,          /* zName */
  0,                     /* pAppData */







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static int devsymFileSize(sqlite3_file*, sqlite3_int64 *pSize);
static int devsymLock(sqlite3_file*, int);
static int devsymUnlock(sqlite3_file*, int);
static int devsymCheckReservedLock(sqlite3_file*, int *);
static int devsymFileControl(sqlite3_file*, int op, void *pArg);
static int devsymSectorSize(sqlite3_file*);
static int devsymDeviceCharacteristics(sqlite3_file*);
static int devsymShmOpen(sqlite3_file*);
static int devsymShmSize(sqlite3_file*,int,int*);
static int devsymShmGet(sqlite3_file*,int,int*,void**);
static int devsymShmRelease(sqlite3_file*);
static int devsymShmLock(sqlite3_file*,int,int*);
static int devsymShmClose(sqlite3_file*,int);

/*
** Method declarations for devsym_vfs.
*/
static int devsymOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
static int devsymDelete(sqlite3_vfs*, const char *zName, int syncDir);
static int devsymAccess(sqlite3_vfs*, const char *zName, int flags, int *);
static int devsymFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
#ifndef SQLITE_OMIT_LOAD_EXTENSION
static void *devsymDlOpen(sqlite3_vfs*, const char *zFilename);
static void devsymDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
static void (*devsymDlSym(sqlite3_vfs*,void*, const char *zSymbol))(void);
static void devsymDlClose(sqlite3_vfs*, void*);
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
static int devsymRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int devsymSleep(sqlite3_vfs*, int microseconds);
static int devsymCurrentTime(sqlite3_vfs*, double*);








static sqlite3_vfs devsym_vfs = {
  2,                     /* iVersion */
  sizeof(devsym_file),      /* szOsFile */
  DEVSYM_MAX_PATHNAME,      /* mxPathname */
  0,                     /* pNext */
  DEVSYM_VFS_NAME,          /* zName */
  0,                     /* pAppData */
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  0,                        /* xDlSym */
  0,                        /* xDlClose */
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
  devsymRandomness,         /* xRandomness */
  devsymSleep,              /* xSleep */
  devsymCurrentTime,        /* xCurrentTime */
  0,                        /* xGetLastError */
  devsymShmOpen,
  devsymShmSize,
  devsymShmGet,
  devsymShmRelease,
  devsymShmLock,
  devsymShmClose,
  0,
  0,
};

static sqlite3_io_methods devsym_io_methods = {
  1,                            /* iVersion */
  devsymClose,                      /* xClose */
  devsymRead,                       /* xRead */
  devsymWrite,                      /* xWrite */
  devsymTruncate,                   /* xTruncate */
  devsymSync,                       /* xSync */
  devsymFileSize,                   /* xFileSize */
  devsymLock,                       /* xLock */
  devsymUnlock,                     /* xUnlock */
  devsymCheckReservedLock,          /* xCheckReservedLock */
  devsymFileControl,                /* xFileControl */
  devsymSectorSize,                 /* xSectorSize */
  devsymDeviceCharacteristics       /* xDeviceCharacteristics */






};

struct DevsymGlobal {
  sqlite3_vfs *pVfs;
  int iDeviceChar;
  int iSectorSize;
};







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  0,                        /* xDlSym */
  0,                        /* xDlClose */
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
  devsymRandomness,         /* xRandomness */
  devsymSleep,              /* xSleep */
  devsymCurrentTime,        /* xCurrentTime */
  0,                        /* xGetLastError */
  0,                        /* xRename */
  0                         /* xCurrentTimeInt64 */






};

static sqlite3_io_methods devsym_io_methods = {
  2,                                /* iVersion */
  devsymClose,                      /* xClose */
  devsymRead,                       /* xRead */
  devsymWrite,                      /* xWrite */
  devsymTruncate,                   /* xTruncate */
  devsymSync,                       /* xSync */
  devsymFileSize,                   /* xFileSize */
  devsymLock,                       /* xLock */
  devsymUnlock,                     /* xUnlock */
  devsymCheckReservedLock,          /* xCheckReservedLock */
  devsymFileControl,                /* xFileControl */
  devsymSectorSize,                 /* xSectorSize */
  devsymDeviceCharacteristics,      /* xDeviceCharacteristics */
  devsymShmOpen,                    /* xShmOpen */
  devsymShmSize,                    /* xShmSize */
  devsymShmGet,                     /* xShmGet */
  devsymShmRelease,                 /* xShmRelease */
  devsymShmLock,                    /* xShmLock */
  devsymShmClose                    /* xShmClose */
};

struct DevsymGlobal {
  sqlite3_vfs *pVfs;
  int iDeviceChar;
  int iSectorSize;
};
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/*
** Return the device characteristic flags supported by an devsym-file.
*/
static int devsymDeviceCharacteristics(sqlite3_file *pFile){
  return g.iDeviceChar;
}































/*
** Open an devsym file handle.
*/
static int devsymOpen(
  sqlite3_vfs *pVfs,
  const char *zName,







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/*
** Return the device characteristic flags supported by an devsym-file.
*/
static int devsymDeviceCharacteristics(sqlite3_file *pFile){
  return g.iDeviceChar;
}

/*
** Shared-memory methods are all pass-thrus.
*/
static int devsymShmOpen(sqlite3_file *pFile){
  devsym_file *p = (devsym_file *)pFile;
  return sqlite3OsShmOpen(p->pReal);
}
static int devsymShmSize(sqlite3_file *pFile, int reqSize, int *pSize){
  devsym_file *p = (devsym_file *)pFile;
  return sqlite3OsShmSize(p->pReal, reqSize, pSize);
}
static int devsymShmGet(sqlite3_file *pFile, int reqSz, int *pSize, void **pp){
  devsym_file *p = (devsym_file *)pFile;
  return sqlite3OsShmGet(p->pReal, reqSz, pSize, pp);
}
static int devsymShmRelease(sqlite3_file *pFile){
  devsym_file *p = (devsym_file *)pFile;
  return sqlite3OsShmRelease(p->pReal);
}
static int devsymShmLock(sqlite3_file *pFile, int desired, int *pGot){
  devsym_file *p = (devsym_file *)pFile;
  return sqlite3OsShmLock(p->pReal, desired, pGot);
}
static int devsymShmClose(sqlite3_file *pFile, int delFlag){
  devsym_file *p = (devsym_file *)pFile;
  return sqlite3OsShmClose(p->pReal, delFlag);
}



/*
** Open an devsym file handle.
*/
static int devsymOpen(
  sqlite3_vfs *pVfs,
  const char *zName,
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** Return the current time as a Julian Day number in *pTimeOut.
*/
static int devsymCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
  return g.pVfs->xCurrentTime(g.pVfs, pTimeOut);
}


static int devsymShmOpen(
  sqlite3_vfs *pVfs, 
  const char *zName, 
  sqlite3_shm **pp
){
  return g.pVfs->xShmOpen(g.pVfs, zName, pp);
}
static int devsymShmSize(
  sqlite3_vfs *pVfs,
  sqlite3_shm *p,
  int reqSize,
  int *pNewSize
){
  return g.pVfs->xShmSize(g.pVfs, p, reqSize, pNewSize);
}
static int devsymShmGet(
  sqlite3_vfs *pVfs,
  sqlite3_shm *p, 
  int reqMapSize, 
  int *pMapSize, 
  void **pp
){
  return g.pVfs->xShmGet(g.pVfs, p, reqMapSize, pMapSize, pp);
}
static int devsymShmRelease(sqlite3_vfs *pVfs, sqlite3_shm *p){
  return g.pVfs->xShmRelease(g.pVfs, p);
}
static int devsymShmLock(
  sqlite3_vfs *pVfs,
  sqlite3_shm *p,
  int desiredLock,
  int *gotLock
){
  return g.pVfs->xShmLock(g.pVfs, p, desiredLock, gotLock);
}
static int devsymShmClose(sqlite3_vfs *pVfs, sqlite3_shm *p, int deleteFlag){
  return g.pVfs->xShmClose(g.pVfs, p, deleteFlag);
}

/*
** This procedure registers the devsym vfs with SQLite. If the argument is
** true, the devsym vfs becomes the new default vfs. It is the only publicly
** available function in this file.
*/
void devsym_register(int iDeviceChar, int iSectorSize){
  if( g.pVfs==0 ){
    g.pVfs = sqlite3_vfs_find(0);
    devsym_vfs.szOsFile += g.pVfs->szOsFile;
    devsym_vfs.xShmOpen = (g.pVfs->xShmOpen ? devsymShmOpen : 0);
    devsym_vfs.xShmSize = (g.pVfs->xShmSize ? devsymShmSize : 0);
    devsym_vfs.xShmGet = (g.pVfs->xShmGet ? devsymShmGet : 0);
    devsym_vfs.xShmRelease = (g.pVfs->xShmRelease ? devsymShmRelease : 0);
    devsym_vfs.xShmLock = (g.pVfs->xShmLock ? devsymShmLock : 0);
    devsym_vfs.xShmClose = (g.pVfs->xShmClose ? devsymShmClose : 0);
    sqlite3_vfs_register(&devsym_vfs, 0);
  }
  if( iDeviceChar>=0 ){
    g.iDeviceChar = iDeviceChar;
  }else{
    g.iDeviceChar = 0;
  }







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** Return the current time as a Julian Day number in *pTimeOut.
*/
static int devsymCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
  return g.pVfs->xCurrentTime(g.pVfs, pTimeOut);
}









































/*
** This procedure registers the devsym vfs with SQLite. If the argument is
** true, the devsym vfs becomes the new default vfs. It is the only publicly
** available function in this file.
*/
void devsym_register(int iDeviceChar, int iSectorSize){
  if( g.pVfs==0 ){
    g.pVfs = sqlite3_vfs_find(0);
    devsym_vfs.szOsFile += g.pVfs->szOsFile;






    sqlite3_vfs_register(&devsym_vfs, 0);
  }
  if( iDeviceChar>=0 ){
    g.iDeviceChar = iDeviceChar;
  }else{
    g.iDeviceChar = 0;
  }
Changes to src/test_onefile.c.
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    fsDlOpen,                                   /* xDlOpen */
    fsDlError,                                  /* xDlError */
    fsDlSym,                                    /* xDlSym */
    fsDlClose,                                  /* xDlClose */
    fsRandomness,                               /* xRandomness */
    fsSleep,                                    /* xSleep */
    fsCurrentTime,                              /* xCurrentTime */
    0,                                          /* xShmOpen */
    0,                                          /* xShmSize */
    0,                                          /* xShmLock */
    0,                                          /* xShmClose */
    0,                                          /* xShmDelete */
    0,                                          /* xRename */
    0                                           /* xCurrentTimeInt64 */
  }, 
  0,                                            /* pFileList */
  0                                             /* pParent */
};

static sqlite3_io_methods fs_io_methods = {
  1,                            /* iVersion */
  fsClose,                      /* xClose */
  fsRead,                       /* xRead */
  fsWrite,                      /* xWrite */
  fsTruncate,                   /* xTruncate */
  fsSync,                       /* xSync */
  fsFileSize,                   /* xFileSize */
  fsLock,                       /* xLock */
  fsUnlock,                     /* xUnlock */
  fsCheckReservedLock,          /* xCheckReservedLock */
  fsFileControl,                /* xFileControl */
  fsSectorSize,                 /* xSectorSize */
  fsDeviceCharacteristics       /* xDeviceCharacteristics */





};


static sqlite3_io_methods tmp_io_methods = {
  1,                            /* iVersion */
  tmpClose,                     /* xClose */
  tmpRead,                      /* xRead */
  tmpWrite,                     /* xWrite */
  tmpTruncate,                  /* xTruncate */
  tmpSync,                      /* xSync */
  tmpFileSize,                  /* xFileSize */
  tmpLock,                      /* xLock */
  tmpUnlock,                    /* xUnlock */
  tmpCheckReservedLock,         /* xCheckReservedLock */
  tmpFileControl,               /* xFileControl */
  tmpSectorSize,                /* xSectorSize */
  tmpDeviceCharacteristics      /* xDeviceCharacteristics */





};

/* Useful macros used in several places */
#define MIN(x,y) ((x)<(y)?(x):(y))
#define MAX(x,y) ((x)>(y)?(x):(y))









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    fsDlOpen,                                   /* xDlOpen */
    fsDlError,                                  /* xDlError */
    fsDlSym,                                    /* xDlSym */
    fsDlClose,                                  /* xDlClose */
    fsRandomness,                               /* xRandomness */
    fsSleep,                                    /* xSleep */
    fsCurrentTime,                              /* xCurrentTime */





    0,                                          /* xRename */
    0                                           /* xCurrentTimeInt64 */
  }, 
  0,                                            /* pFileList */
  0                                             /* pParent */
};

static sqlite3_io_methods fs_io_methods = {
  1,                            /* iVersion */
  fsClose,                      /* xClose */
  fsRead,                       /* xRead */
  fsWrite,                      /* xWrite */
  fsTruncate,                   /* xTruncate */
  fsSync,                       /* xSync */
  fsFileSize,                   /* xFileSize */
  fsLock,                       /* xLock */
  fsUnlock,                     /* xUnlock */
  fsCheckReservedLock,          /* xCheckReservedLock */
  fsFileControl,                /* xFileControl */
  fsSectorSize,                 /* xSectorSize */
  fsDeviceCharacteristics,      /* xDeviceCharacteristics */
  0,                            /* xShmOpen */
  0,                            /* xShmSize */
  0,                            /* xShmLock */
  0,                            /* xShmClose */
  0,                            /* xShmDelete */
};


static sqlite3_io_methods tmp_io_methods = {
  1,                            /* iVersion */
  tmpClose,                     /* xClose */
  tmpRead,                      /* xRead */
  tmpWrite,                     /* xWrite */
  tmpTruncate,                  /* xTruncate */
  tmpSync,                      /* xSync */
  tmpFileSize,                  /* xFileSize */
  tmpLock,                      /* xLock */
  tmpUnlock,                    /* xUnlock */
  tmpCheckReservedLock,         /* xCheckReservedLock */
  tmpFileControl,               /* xFileControl */
  tmpSectorSize,                /* xSectorSize */
  tmpDeviceCharacteristics,     /* xDeviceCharacteristics */
  0,                            /* xShmOpen */
  0,                            /* xShmSize */
  0,                            /* xShmLock */
  0,                            /* xShmClose */
  0,                            /* xShmDelete */
};

/* Useful macros used in several places */
#define MIN(x,y) ((x)<(y)?(x):(y))
#define MAX(x,y) ((x)>(y)?(x):(y))


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******************************************************************************
**
** This file contains the implementation of an SQLite vfs wrapper that
** adds instrumentation to all vfs and file methods. C and Tcl interfaces
** are provided to control the instrumentation.
*/

#ifdef SQLITE_ENABLE_INSTVFS
/*

** C interface:
**
**   sqlite3_instvfs_create()
**   sqlite3_instvfs_destroy()
**   sqlite3_instvfs_configure()
**
**   sqlite3_instvfs_reset()
**   sqlite3_instvfs_get()
**
**   sqlite3_instvfs_binarylog
**   sqlite3_instvfs_binarylog_marker
**
** Tcl interface (omitted if SQLITE_TEST is not set):
** 
**   sqlite3_instvfs create NAME ?PARENT?
**
**       Create and register new vfs called $NAME, which is a wrapper around
**       the existing vfs $PARENT. If the PARENT argument is omitted, the
**       new vfs is a wrapper around the current default vfs.
**
**   sqlite3_instvfs destroy NAME
**
**       Deregister and destroy the vfs named $NAME, which must have been
**       created by an earlier invocation of [sqlite3_instvfs create].
**
**   sqlite3_instvfs configure NAME SCRIPT
**
**       Configure the callback script for the vfs $NAME, which much have
**       been created by an earlier invocation of [sqlite3_instvfs create].
**       After a callback script has been configured, it is invoked each
**       time a vfs or file method is called by SQLite. Before invoking
**       the callback script, five arguments are appended to it:
**
**         * The name of the invoked method - i.e. "xRead".
**
**         * The time consumed by the method call as measured by 
**           sqlite3Hwtime() (an integer value)
**
**         * A string value with a different meaning for different calls. 
**           For file methods, the name of the file being operated on. For
**           other methods it is the filename argument, if any.

**
**         * A 32-bit integer value with a call-specific meaning.
**
**         * A 64-bit integer value. For xRead() and xWrite() calls this
**           is the file offset being written to or read from. Unused by
**           all other calls.
**
**   sqlite3_instvfs reset NAME

**
**       Zero the internal event counters associated with vfs $NAME, 
**       which must have been created by an earlier invocation of 
**       [sqlite3_instvfs create].
**
**   sqlite3_instvfs report NAME
**
**       Return the values of the internal event counters associated 
**       with vfs $NAME. The report format is a list with one element
**       for each method call (xWrite, xRead etc.). Each element is

**       itself a list with three elements:
**
**         * The name of the method call - i.e. "xWrite",
**         * The total number of calls to the method (an integer).


**         * The aggregate time consumed by all calls to the method as


**           measured by sqlite3Hwtime() (an integer).
*/

#include "sqlite3.h"
#include <string.h>
#include <assert.h>


/*
** Maximum pathname length supported by the inst backend.
*/
#define INST_MAX_PATHNAME 512


/* File methods */
/* Vfs methods */
#define OS_ACCESS            1
#define OS_CHECKRESERVEDLOCK 2
#define OS_CLOSE             3
#define OS_CURRENTTIME       4
#define OS_DELETE            5
#define OS_DEVCHAR           6
#define OS_FILECONTROL       7
#define OS_FILESIZE          8
#define OS_FULLPATHNAME      9
#define OS_LOCK              11
#define OS_OPEN              12
#define OS_RANDOMNESS        13
#define OS_READ              14 
#define OS_SECTORSIZE        15
#define OS_SLEEP             16
#define OS_SYNC              17
#define OS_TRUNCATE          18
#define OS_UNLOCK            19
#define OS_WRITE             20








#define OS_NUMEVENTS         21

#define BINARYLOG_STRING     30
#define BINARYLOG_MARKER     31

#define BINARYLOG_PREPARE_V2 64
#define BINARYLOG_STEP       65
#define BINARYLOG_FINALIZE   66



struct InstVfs {
  sqlite3_vfs base;
  sqlite3_vfs *pVfs;

  void *pClient;
  void (*xDel)(void *);
  void (*xCall)(void *, int, int, sqlite3_int64, int, const char *, int, int, sqlite3_int64);

  /* Counters */
  sqlite3_int64 aTime[OS_NUMEVENTS];
  int aCount[OS_NUMEVENTS];




  int iNextFileId;




};
typedef struct InstVfs InstVfs;

#define REALVFS(p) (((InstVfs *)(p))->pVfs)

typedef struct inst_file inst_file;
struct inst_file {
  sqlite3_file base;
  sqlite3_file *pReal;
  InstVfs *pInstVfs;
  const char *zName;
  int iFileId;               /* File id number */
  int flags;
};

/*
** Method declarations for inst_file.
*/
static int instClose(sqlite3_file*);
static int instRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int instWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
static int instTruncate(sqlite3_file*, sqlite3_int64 size);
static int instSync(sqlite3_file*, int flags);
static int instFileSize(sqlite3_file*, sqlite3_int64 *pSize);
static int instLock(sqlite3_file*, int);
static int instUnlock(sqlite3_file*, int);
static int instCheckReservedLock(sqlite3_file*, int *pResOut);
static int instFileControl(sqlite3_file*, int op, void *pArg);
static int instSectorSize(sqlite3_file*);
static int instDeviceCharacteristics(sqlite3_file*);








/*
** Method declarations for inst_vfs.
*/
static int instOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
static int instDelete(sqlite3_vfs*, const char *zName, int syncDir);
static int instAccess(sqlite3_vfs*, const char *zName, int flags, int *);
static int instFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
static void *instDlOpen(sqlite3_vfs*, const char *zFilename);
static void instDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
static void (*instDlSym(sqlite3_vfs *pVfs, void *p, const char*zSym))(void);
static void instDlClose(sqlite3_vfs*, void*);
static int instRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int instSleep(sqlite3_vfs*, int microseconds);
static int instCurrentTime(sqlite3_vfs*, double*);

static void binarylog_blob(sqlite3_vfs *, const char *, int, int); 

static sqlite3_vfs inst_vfs = {
  1,                      /* iVersion */
  sizeof(inst_file),      /* szOsFile */
  INST_MAX_PATHNAME,      /* mxPathname */
  0,                      /* pNext */
  0,                      /* zName */
  0,                      /* pAppData */
  instOpen,               /* xOpen */
  instDelete,             /* xDelete */
  instAccess,             /* xAccess */
  instFullPathname,       /* xFullPathname */
  instDlOpen,             /* xDlOpen */
  instDlError,            /* xDlError */
  instDlSym,              /* xDlSym */
  instDlClose,            /* xDlClose */
  instRandomness,         /* xRandomness */
  instSleep,              /* xSleep */
  instCurrentTime,        /* xCurrentTime */
};

static sqlite3_io_methods inst_io_methods = {
  1,                            /* iVersion */
  instClose,                      /* xClose */
  instRead,                       /* xRead */
  instWrite,                      /* xWrite */
  instTruncate,                   /* xTruncate */
  instSync,                       /* xSync */
  instFileSize,                   /* xFileSize */
  instLock,                       /* xLock */
  instUnlock,                     /* xUnlock */
  instCheckReservedLock,          /* xCheckReservedLock */
  instFileControl,                /* xFileControl */
  instSectorSize,                 /* xSectorSize */
  instDeviceCharacteristics       /* xDeviceCharacteristics */
};

/* 
** hwtime.h contains inline assembler code for implementing 
** high-performance timing routines.
*/
#include "hwtime.h"

#define OS_TIME_IO(eEvent, A, B, Call) {     \
  inst_file *p = (inst_file *)pFile;         \
  InstVfs *pInstVfs = p->pInstVfs;           \
  int rc;                                    \

  sqlite_uint64 t = sqlite3Hwtime();         \
  rc = Call;                                 \

  t = sqlite3Hwtime() - t;                   \
  pInstVfs->aTime[eEvent] += t;              \
  pInstVfs->aCount[eEvent] += 1;             \
  if( pInstVfs->xCall ){                     \
    pInstVfs->xCall(                         \
      pInstVfs->pClient,eEvent,p->iFileId,t,rc,p->zName,p->flags,A,B  \
    );                                       \
  }                                          \
  return rc;                                 \
}





#define OS_TIME_VFS(eEvent, Z, flags, A, B, Call) {      \
  InstVfs *pInstVfs = (InstVfs *)pVfs;   \
  int rc;                                \
  sqlite_uint64 t = sqlite3Hwtime();     \
  rc = Call;                             \
  t = sqlite3Hwtime() - t;               \
  pInstVfs->aTime[eEvent] += t;          \
  pInstVfs->aCount[eEvent] += 1;         \
  if( pInstVfs->xCall ){                 \
    pInstVfs->xCall(pInstVfs->pClient,eEvent,0, t, rc, Z, flags, A, B); \
  }                                      \
  return rc;                             \
}

/*
** Close an inst-file.
*/
static int instClose(sqlite3_file *pFile){



  OS_TIME_IO(OS_CLOSE, 0, 0, 


    (p->pReal->pMethods ? p->pReal->pMethods->xClose(p->pReal) : SQLITE_OK)

  );


}

/*
** Read data from an inst-file.
*/
static int instRead(
  sqlite3_file *pFile, 
  void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){


  sqlite3_vfs *pVfs = (sqlite3_vfs *)(((inst_file *)pFile)->pInstVfs);
  OS_TIME_IO(OS_READ, iAmt, (binarylog_blob(pVfs, zBuf, iAmt, 1), iOfst), 

      p->pReal->pMethods->xRead(p->pReal, zBuf, iAmt, iOfst)
  );



}

/*
** Write data to an inst-file.
*/
static int instWrite(
  sqlite3_file *pFile,
  const void *z,
  int iAmt,
  sqlite_int64 iOfst
){


  sqlite3_vfs *pVfs = (sqlite3_vfs *)(((inst_file *)pFile)->pInstVfs);
  binarylog_blob(pVfs, z, iAmt, 1);
  OS_TIME_IO(OS_WRITE, iAmt, iOfst, 
      p->pReal->pMethods->xWrite(p->pReal, z, iAmt, iOfst)
  );



}

/*
** Truncate an inst-file.
*/
static int instTruncate(sqlite3_file *pFile, sqlite_int64 size){
  OS_TIME_IO(OS_TRUNCATE, 0, (int)size, 



    p->pReal->pMethods->xTruncate(p->pReal, size)
  );



}

/*
** Sync an inst-file.
*/
static int instSync(sqlite3_file *pFile, int flags){




  OS_TIME_IO(OS_SYNC, flags, 0, p->pReal->pMethods->xSync(p->pReal, flags));



}















/*
** Return the current file-size of an inst-file.
*/
static int instFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
  OS_TIME_IO(OS_FILESIZE, (int)(*pSize), 0, 



    p->pReal->pMethods->xFileSize(p->pReal, pSize)
  );



}

/*
** Lock an inst-file.
*/
static int instLock(sqlite3_file *pFile, int eLock){




  OS_TIME_IO(OS_LOCK, eLock, 0, p->pReal->pMethods->xLock(p->pReal, eLock));



}























/*
** Unlock an inst-file.

*/
static int instUnlock(sqlite3_file *pFile, int eLock){




  OS_TIME_IO(OS_UNLOCK, eLock, 0, p->pReal->pMethods->xUnlock(p->pReal, eLock));



}

/*
** Check if another file-handle holds a RESERVED lock on an inst-file.

*/
static int instCheckReservedLock(sqlite3_file *pFile, int *pResOut){
  OS_TIME_IO(OS_CHECKRESERVEDLOCK, 0, 0, 




      p->pReal->pMethods->xCheckReservedLock(p->pReal, pResOut)
  );



}

/*
** File control method. For custom operations on an inst-file.
*/
static int instFileControl(sqlite3_file *pFile, int op, void *pArg){




  OS_TIME_IO(OS_FILECONTROL, 0, 0, p->pReal->pMethods->xFileControl(p->pReal, op, pArg));



}










/*








** Return the sector-size in bytes for an inst-file.
*/

static int instSectorSize(sqlite3_file *pFile){




  OS_TIME_IO(OS_SECTORSIZE, 0, 0, p->pReal->pMethods->xSectorSize(p->pReal));



}










/*
** Return the device characteristic flags supported by an inst-file.
*/
static int instDeviceCharacteristics(sqlite3_file *pFile){




  OS_TIME_IO(OS_DEVCHAR, 0, 0, p->pReal->pMethods->xDeviceCharacteristics(p->pReal));



}


/*
** Open an inst file handle.
*/
static int instOpen(
  sqlite3_vfs *pVfs,
  const char *zName,
  sqlite3_file *pFile,
  int flags,
  int *pOutFlags
){




  inst_file *p = (inst_file *)pFile;
  pFile->pMethods = &inst_io_methods;
  p->pReal = (sqlite3_file *)&p[1];
  p->pInstVfs = (InstVfs *)pVfs;
  p->zName = zName;
  p->flags = flags;
  p->iFileId = ++p->pInstVfs->iNextFileId;

  binarylog_blob(pVfs, zName, -1, 0);
  OS_TIME_VFS(OS_OPEN, zName, flags, p->iFileId, 0,
    REALVFS(pVfs)->xOpen(REALVFS(pVfs), zName, p->pReal, flags, pOutFlags)

  );



}

/*
** Delete the file located at zPath. If the dirSync argument is true,
** ensure the file-system modifications are synced to disk before
** returning.
*/
static int instDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){


  binarylog_blob(pVfs, zPath, -1, 0);
  OS_TIME_VFS(OS_DELETE, zPath, 0, dirSync, 0,
    REALVFS(pVfs)->xDelete(REALVFS(pVfs), zPath, dirSync) 


  );

}

/*
** Test for access permissions. Return true if the requested permission
** is available, or false otherwise.
*/
static int instAccess(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int flags, 
  int *pResOut
){


  binarylog_blob(pVfs, zPath, -1, 0);
  OS_TIME_VFS(OS_ACCESS, zPath, 0, flags, *pResOut, 
    REALVFS(pVfs)->xAccess(REALVFS(pVfs), zPath, flags, pResOut) 


  );

}

/*
** Populate buffer zOut with the full canonical pathname corresponding
** to the pathname in zPath. zOut is guaranteed to point to a buffer
** of at least (INST_MAX_PATHNAME+1) bytes.
*/
static int instFullPathname(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int nOut, 
  char *zOut
){
  OS_TIME_VFS( OS_FULLPATHNAME, zPath, 0, 0, 0,
    REALVFS(pVfs)->xFullPathname(REALVFS(pVfs), zPath, nOut, zOut);
  );
}

/*
** Open the dynamic library located at zPath and return a handle.
*/
static void *instDlOpen(sqlite3_vfs *pVfs, const char *zPath){
  return REALVFS(pVfs)->xDlOpen(REALVFS(pVfs), zPath);
}

/*
** Populate the buffer zErrMsg (size nByte bytes) with a human readable
** utf-8 string describing the most recent error encountered associated 
** with dynamic libraries.
*/
static void instDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
  REALVFS(pVfs)->xDlError(REALVFS(pVfs), nByte, zErrMsg);
}

/*
** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
*/
static void (*instDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
  return REALVFS(pVfs)->xDlSym(REALVFS(pVfs), p, zSym);
}

/*
** Close the dynamic library handle pHandle.
*/
static void instDlClose(sqlite3_vfs *pVfs, void *pHandle){
  REALVFS(pVfs)->xDlClose(REALVFS(pVfs), pHandle);
}

/*
** Populate the buffer pointed to by zBufOut with nByte bytes of 
** random data.
*/
static int instRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
  OS_TIME_VFS( OS_RANDOMNESS, 0, 0, nByte, 0,
    REALVFS(pVfs)->xRandomness(REALVFS(pVfs), nByte, zBufOut);
  );
}

/*
** Sleep for nMicro microseconds. Return the number of microseconds 
** actually slept.
*/
static int instSleep(sqlite3_vfs *pVfs, int nMicro){
  OS_TIME_VFS( OS_SLEEP, 0, 0, nMicro, 0, 
    REALVFS(pVfs)->xSleep(REALVFS(pVfs), nMicro) 
  );
}

/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int instCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
  OS_TIME_VFS( OS_CURRENTTIME, 0, 0, 0, 0,
    REALVFS(pVfs)->xCurrentTime(REALVFS(pVfs), pTimeOut) 
  );
}

sqlite3_vfs *sqlite3_instvfs_create(const char *zName, const char *zParent){
  int nByte;
  InstVfs *p;
  sqlite3_vfs *pParent;

  pParent = sqlite3_vfs_find(zParent);
  if( !pParent ){
    return 0;
  }

  nByte = strlen(zName) + 1 + sizeof(InstVfs);
  p = (InstVfs *)sqlite3_malloc(nByte);
  if( p ){
    char *zCopy = (char *)&p[1];
    memset(p, 0, nByte);
    memcpy(p, &inst_vfs, sizeof(sqlite3_vfs));
    p->pVfs = pParent;
    memcpy(zCopy, zName, strlen(zName));
    p->base.zName = (const char *)zCopy;
    p->base.szOsFile += pParent->szOsFile;
    sqlite3_vfs_register((sqlite3_vfs *)p, 0);
  }

  return (sqlite3_vfs *)p;
}

void sqlite3_instvfs_configure(
  sqlite3_vfs *pVfs,
  void (*xCall)(
      void*, 
      int,                           /* File id */
      int,                           /* Event code */
      sqlite3_int64, 
      int,                           /* Return code */
      const char*,                   /* File name */
      int, 
      int, 
      sqlite3_int64
  ),
  void *pClient,
  void (*xDel)(void *)
){
  InstVfs *p = (InstVfs *)pVfs;
  assert( pVfs->xOpen==instOpen );
  if( p->xDel ){
    p->xDel(p->pClient);
  }
  p->xCall = xCall;
  p->xDel = xDel;
  p->pClient = pClient;
}

void sqlite3_instvfs_destroy(sqlite3_vfs *pVfs){
  if( pVfs ){
    sqlite3_vfs_unregister(pVfs);
    sqlite3_instvfs_configure(pVfs, 0, 0, 0);
    sqlite3_free(pVfs);
  }
}

void sqlite3_instvfs_reset(sqlite3_vfs *pVfs){
  InstVfs *p = (InstVfs *)pVfs;
  assert( pVfs->xOpen==instOpen );
  memset(p->aTime, 0, sizeof(sqlite3_int64)*OS_NUMEVENTS);
  memset(p->aCount, 0, sizeof(int)*OS_NUMEVENTS);
}

const char *sqlite3_instvfs_name(int eEvent){
  const char *zEvent = 0;

  switch( eEvent ){
    case OS_CLOSE:             zEvent = "xClose"; break;
    case OS_READ:              zEvent = "xRead"; break;
    case OS_WRITE:             zEvent = "xWrite"; break;
    case OS_TRUNCATE:          zEvent = "xTruncate"; break;
    case OS_SYNC:              zEvent = "xSync"; break;
    case OS_FILESIZE:          zEvent = "xFilesize"; break;
    case OS_LOCK:              zEvent = "xLock"; break;
    case OS_UNLOCK:            zEvent = "xUnlock"; break;
    case OS_CHECKRESERVEDLOCK: zEvent = "xCheckReservedLock"; break;
    case OS_FILECONTROL:       zEvent = "xFileControl"; break;
    case OS_SECTORSIZE:        zEvent = "xSectorSize"; break;
    case OS_DEVCHAR:           zEvent = "xDeviceCharacteristics"; break;
    case OS_OPEN:              zEvent = "xOpen"; break;
    case OS_DELETE:            zEvent = "xDelete"; break;
    case OS_ACCESS:            zEvent = "xAccess"; break;
    case OS_FULLPATHNAME:      zEvent = "xFullPathname"; break;
    case OS_RANDOMNESS:        zEvent = "xRandomness"; break;
    case OS_SLEEP:             zEvent = "xSleep"; break;
    case OS_CURRENTTIME:       zEvent = "xCurrentTime"; break;
  }

  return zEvent;
}

void sqlite3_instvfs_get(
  sqlite3_vfs *pVfs, 
  int eEvent, 
  const char **pzEvent, 
  sqlite3_int64 *pnClick, 
  int *pnCall
){
  InstVfs *p = (InstVfs *)pVfs;
  assert( pVfs->xOpen==instOpen );
  if( eEvent<1 || eEvent>=OS_NUMEVENTS ){
    *pzEvent = 0;
    *pnClick = 0;
    *pnCall = 0;
    return;
  }

  *pzEvent = sqlite3_instvfs_name(eEvent);
  *pnClick = p->aTime[eEvent];
  *pnCall = p->aCount[eEvent];
}

#define BINARYLOG_BUFFERSIZE 8192

struct InstVfsBinaryLog {
  int nBuf;
  char *zBuf;
  sqlite3_int64 iOffset;
  int log_data;
  sqlite3_file *pOut;
  char *zOut;                       /* Log file name */
};
typedef struct InstVfsBinaryLog InstVfsBinaryLog;

static void put32bits(unsigned char *p, unsigned int v){
  p[0] = v>>24;
  p[1] = v>>16;
  p[2] = v>>8;
  p[3] = v;
}

static void binarylog_flush(InstVfsBinaryLog *pLog){
  sqlite3_file *pFile = pLog->pOut;

#ifdef SQLITE_TEST
  extern int sqlite3_io_error_pending;
  extern int sqlite3_io_error_persist;
  extern int sqlite3_diskfull_pending;

  int pending = sqlite3_io_error_pending;
  int persist = sqlite3_io_error_persist;
  int diskfull = sqlite3_diskfull_pending;

  sqlite3_io_error_pending = 0;
  sqlite3_io_error_persist = 0;
  sqlite3_diskfull_pending = 0;
#endif


  pFile->pMethods->xWrite(pFile, pLog->zBuf, pLog->nBuf, pLog->iOffset);
  pLog->iOffset += pLog->nBuf;
  pLog->nBuf = 0;


#ifdef SQLITE_TEST
  sqlite3_io_error_pending = pending;
  sqlite3_io_error_persist = persist;
  sqlite3_diskfull_pending = diskfull;
#endif
}

static void binarylog_xcall(
  void *p,
  int eEvent,
  int iFileId,
  sqlite3_int64 nClick,
  int return_code,
  const char *zName,
  int flags,
  int nByte,
  sqlite3_int64 iOffset
){
  InstVfsBinaryLog *pLog = (InstVfsBinaryLog *)p;
  unsigned char *zRec;
  if( (28+pLog->nBuf)>BINARYLOG_BUFFERSIZE ){
    binarylog_flush(pLog);
  }
  zRec = (unsigned char *)&pLog->zBuf[pLog->nBuf];
  put32bits(&zRec[0], eEvent);
  put32bits(&zRec[4], (int)iFileId);
  put32bits(&zRec[8], (int)nClick);
  put32bits(&zRec[12], return_code);
  put32bits(&zRec[16], flags);
  put32bits(&zRec[20], nByte);
  put32bits(&zRec[24], (int)iOffset);
  pLog->nBuf += 28;
}

static void binarylog_xdel(void *p){
  /* Close the log file and free the memory allocated for the 
  ** InstVfsBinaryLog structure.
  */
  InstVfsBinaryLog *pLog = (InstVfsBinaryLog *)p;
  sqlite3_file *pFile = pLog->pOut;
  if( pLog->nBuf ){
    binarylog_flush(pLog);
  }
  pFile->pMethods->xClose(pFile);
  sqlite3_free(pLog->pOut);
  sqlite3_free(pLog->zBuf);
  sqlite3_free(pLog);
}

static void binarylog_blob(
  sqlite3_vfs *pVfs,
  const char *zBlob,

  int nBlob,

  int isBinary

){
  InstVfsBinaryLog *pLog;
  InstVfs *pInstVfs = (InstVfs *)pVfs;




  if( pVfs->xOpen!=instOpen || pInstVfs->xCall!=binarylog_xcall ){




    return;



  }
  pLog = (InstVfsBinaryLog *)pInstVfs->pClient;
  if( zBlob && (!isBinary || pLog->log_data) ){


    unsigned char *zRec;
    int nWrite;





    if( nBlob<0 ){
      nBlob = strlen(zBlob);

    }
    nWrite = nBlob + 28;
  
    if( (nWrite+pLog->nBuf)>BINARYLOG_BUFFERSIZE ){


      binarylog_flush(pLog);

    }

  
    zRec = (unsigned char *)&pLog->zBuf[pLog->nBuf];

    memset(zRec, 0, nWrite);
    put32bits(&zRec[0], BINARYLOG_STRING);
    put32bits(&zRec[4], (int)nBlob);
    put32bits(&zRec[8], (int)isBinary);
    memcpy(&zRec[28], zBlob, nBlob);
    pLog->nBuf += nWrite;


  }



}

void sqlite3_instvfs_binarylog_call(
  sqlite3_vfs *pVfs,
  int eEvent,
  sqlite3_int64 nClick,
  int return_code,
  const char *zString


){
  InstVfs *pInstVfs = (InstVfs *)pVfs;
  InstVfsBinaryLog *pLog = (InstVfsBinaryLog *)pInstVfs->pClient;

  if( zString ){
    binarylog_blob(pVfs, zString, -1, 0);
  }
  binarylog_xcall(pLog, eEvent, 0, nClick, return_code, 0, 0, 0, 0);
}

void sqlite3_instvfs_binarylog_marker(
  sqlite3_vfs *pVfs,
  const char *zMarker
){
  InstVfs *pInstVfs = (InstVfs *)pVfs;
  InstVfsBinaryLog *pLog = (InstVfsBinaryLog *)pInstVfs->pClient;
  binarylog_blob(pVfs, zMarker, -1, 0);
  binarylog_xcall(pLog, BINARYLOG_MARKER, 0, 0, 0, 0, 0, 0, 0);
}

sqlite3_vfs *sqlite3_instvfs_binarylog(
  const char *zVfs,
  const char *zParentVfs, 
  const char *zLog,
  int log_data
){
  InstVfsBinaryLog *p;
  sqlite3_vfs *pVfs;
  sqlite3_vfs *pParent;
  int nByte;
  int flags;
  int rc;



  pParent = sqlite3_vfs_find(zParentVfs);
  if( !pParent ){
    return 0;
  }


  nByte = sizeof(InstVfsBinaryLog) + pParent->mxPathname+1;
  p = (InstVfsBinaryLog *)sqlite3_malloc(nByte);
  memset(p, 0, nByte);
  p->zBuf = sqlite3_malloc(BINARYLOG_BUFFERSIZE);

  p->zOut = (char *)&p[1];


  p->pOut = (sqlite3_file *)sqlite3_malloc(pParent->szOsFile);

  p->log_data = log_data;

  pParent->xFullPathname(pParent, zLog, pParent->mxPathname, p->zOut);

  flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MASTER_JOURNAL;
  pParent->xDelete(pParent, p->zOut, 0);
  rc = pParent->xOpen(pParent, p->zOut, p->pOut, flags, &flags);
  if( rc==SQLITE_OK ){
    memcpy(p->zBuf, "sqlite_ostrace1.....", 20);
    p->iOffset = 0;
    p->nBuf = 20;

  }
  if( rc ){




    binarylog_xdel(p);













































    return 0;














































































































































































































  }





  pVfs = sqlite3_instvfs_create(zVfs, zParentVfs);





  if( pVfs ){










    sqlite3_instvfs_configure(pVfs, binarylog_xcall, p, binarylog_xdel);







  }





















  return pVfs;
}
#endif /* SQLITE_ENABLE_INSTVFS */



































/**************************************************************************
***************************************************************************
** Tcl interface starts here.
*/
#if SQLITE_TEST

#include <tcl.h>

#ifdef SQLITE_ENABLE_INSTVFS
struct InstVfsCall {
  Tcl_Interp *interp;
  Tcl_Obj *pScript;
};
typedef struct InstVfsCall InstVfsCall;

static void test_instvfs_xcall(
  void *p,
  int eEvent,
  int iFileId,
  sqlite3_int64 nClick,
  int return_code,
  const char *zName,
  int flags,
  int nByte,
  sqlite3_int64 iOffset
){
  int rc;
  InstVfsCall *pCall = (InstVfsCall *)p;
  Tcl_Obj *pObj = Tcl_DuplicateObj( pCall->pScript);
  const char *zEvent = sqlite3_instvfs_name(eEvent);

  Tcl_IncrRefCount(pObj);
  Tcl_ListObjAppendElement(0, pObj, Tcl_NewStringObj(zEvent, -1));
  Tcl_ListObjAppendElement(0, pObj, Tcl_NewWideIntObj(nClick));
  Tcl_ListObjAppendElement(0, pObj, Tcl_NewStringObj(zName, -1));
  Tcl_ListObjAppendElement(0, pObj, Tcl_NewIntObj(nByte));
  Tcl_ListObjAppendElement(0, pObj, Tcl_NewWideIntObj(iOffset));

  rc = Tcl_EvalObjEx(pCall->interp, pObj, TCL_EVAL_GLOBAL|TCL_EVAL_DIRECT);
  if( rc ){
    Tcl_BackgroundError(pCall->interp);
  }
  Tcl_DecrRefCount(pObj);
}

static void test_instvfs_xdel(void *p){
  InstVfsCall *pCall = (InstVfsCall *)p;
  Tcl_DecrRefCount(pCall->pScript);
  sqlite3_free(pCall);
}

static int test_sqlite3_instvfs(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){





  static const char *IV_strs[] = 
               { "create",  "destroy",  "reset",  "report", "configure", "binarylog", "marker", 0 };
  enum IV_enum { IV_CREATE, IV_DESTROY, IV_RESET, IV_REPORT, IV_CONFIGURE, IV_BINARYLOG, IV_MARKER };
  int iSub;

  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUB-COMMAND ...");

  }
  if( Tcl_GetIndexFromObj(interp, objv[1], IV_strs, "sub-command", 0, &iSub) ){
    return TCL_ERROR;
  }

  switch( (enum IV_enum)iSub ){
    case IV_CREATE: {

      char *zParent = 0;
      sqlite3_vfs *p;
      int isDefault = 0;
      if( objc>2 && 0==strcmp("-default", Tcl_GetString(objv[2])) ){
        isDefault = 1;
      }
      if( (objc-isDefault)!=4 && (objc-isDefault)!=3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "?-default? NAME ?PARENT-VFS?");
        return TCL_ERROR;
      }
      if( objc==(4+isDefault) ){
        zParent = Tcl_GetString(objv[3+isDefault]);
      }
      p = sqlite3_instvfs_create(Tcl_GetString(objv[2+isDefault]), zParent);

      if( !p ){
        Tcl_AppendResult(interp, "error creating vfs ", 0);
        return TCL_ERROR;
      }
      if( isDefault ){
        sqlite3_vfs_register(p, 1);
      }
      Tcl_SetObjResult(interp, objv[2]);
      break;
    }
    case IV_BINARYLOG: {
      char *zName = 0;
      char *zLog = 0;
      char *zParent = 0;
      sqlite3_vfs *p;
      int isDefault = 0;
      int isLogdata = 0;
      int argbase = 2;

      for(argbase=2; argbase<(objc-2); argbase++){
        if( 0==strcmp("-default", Tcl_GetString(objv[argbase])) ){
          isDefault = 1;
        }
        else if( 0==strcmp("-parent", Tcl_GetString(objv[argbase])) ){
          argbase++;
          zParent = Tcl_GetString(objv[argbase]);
        }
        else if( 0==strcmp("-logdata", Tcl_GetString(objv[argbase])) ){
          isLogdata = 1;
        }else{
          break;
        }
      }

      if( (objc-argbase)!=2 ){
        Tcl_WrongNumArgs(
            interp, 2, objv, "?-default? ?-parent VFS? ?-logdata? NAME LOGFILE"
        );
        return TCL_ERROR;
      }
      zName = Tcl_GetString(objv[argbase]);
      zLog = Tcl_GetString(objv[argbase+1]);
      p = sqlite3_instvfs_binarylog(zName, zParent, zLog, isLogdata);
      if( !p ){
        Tcl_AppendResult(interp, "error creating vfs ", 0);
        return TCL_ERROR;
      }
      if( isDefault ){
        sqlite3_vfs_register(p, 1);
      }
      Tcl_SetObjResult(interp, objv[2]);
      break;
    }

    case IV_MARKER: {
      sqlite3_vfs *p;
      if( objc!=4 ){
        Tcl_WrongNumArgs(interp, 2, objv, "VFS MARKER");
        return TCL_ERROR;
      }
      p = sqlite3_vfs_find(Tcl_GetString(objv[2]));

      if( !p || p->xOpen!=instOpen ){
        Tcl_AppendResult(interp, "no such vfs: ", Tcl_GetString(objv[2]), 0);
        return TCL_ERROR;
      }
      sqlite3_instvfs_binarylog_marker(p, Tcl_GetString(objv[3]));
      Tcl_ResetResult(interp);
      break;
    }

    case IV_CONFIGURE: {

      InstVfsCall *pCall;

      sqlite3_vfs *p;
      if( objc!=4 ){
        Tcl_WrongNumArgs(interp, 2, objv, "NAME SCRIPT");
        return TCL_ERROR;
      }
      p = sqlite3_vfs_find(Tcl_GetString(objv[2]));
      if( !p || p->xOpen!=instOpen ){
        Tcl_AppendResult(interp, "no such vfs: ", Tcl_GetString(objv[2]), 0);
        return TCL_ERROR;
      }

      if( strlen(Tcl_GetString(objv[3])) ){
        pCall = (InstVfsCall *)sqlite3_malloc(sizeof(InstVfsCall));
        pCall->interp = interp;
        pCall->pScript = Tcl_DuplicateObj(objv[3]);
        Tcl_IncrRefCount(pCall->pScript);
        sqlite3_instvfs_configure(p, 
            test_instvfs_xcall, (void *)pCall, test_instvfs_xdel
        );
      }else{
        sqlite3_instvfs_configure(p, 0, 0, 0);
      }
      break;
    }

    case IV_REPORT:
    case IV_DESTROY:
    case IV_RESET: {
      sqlite3_vfs *p;
      if( objc!=3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "NAME");
        return TCL_ERROR;
      }
      p = sqlite3_vfs_find(Tcl_GetString(objv[2]));
      if( !p || p->xOpen!=instOpen ){
        Tcl_AppendResult(interp, "no such vfs: ", Tcl_GetString(objv[2]), 0);
        return TCL_ERROR;
      }

      if( ((enum IV_enum)iSub)==IV_DESTROY ){
        sqlite3_instvfs_destroy(p);
      }
      if( ((enum IV_enum)iSub)==IV_RESET ){
        sqlite3_instvfs_reset(p);
      }
      if( ((enum IV_enum)iSub)==IV_REPORT ){
        int ii;
        Tcl_Obj *pRet = Tcl_NewObj();

        const char *zName = (char *)1;
        sqlite3_int64 nClick;
        int nCall;
        for(ii=1; zName; ii++){
          sqlite3_instvfs_get(p, ii, &zName, &nClick, &nCall);
          if( zName ){
            Tcl_Obj *pElem = Tcl_NewObj();
            Tcl_ListObjAppendElement(0, pElem, Tcl_NewStringObj(zName, -1));
            Tcl_ListObjAppendElement(0, pElem, Tcl_NewIntObj(nCall));
            Tcl_ListObjAppendElement(0, pElem, Tcl_NewWideIntObj(nClick));
            Tcl_ListObjAppendElement(0, pRet, pElem);

          }
        }

        Tcl_SetObjResult(interp, pRet);
      }

      break;
    }
  }


  return TCL_OK;
}
#endif /* SQLITE_ENABLE_INSTVFS */

/* Alternative implementation of sqlite3_instvfs when the real
** implementation is unavailable. 
*/
#ifndef SQLITE_ENABLE_INSTVFS
static int test_sqlite3_instvfs(
  void * clientData,
  Tcl_Interp *interp,
  int objc,


  Tcl_Obj *CONST objv[]
){
  Tcl_AppendResult(interp, 
     "not compiled with -DSQLITE_ENABLE_INSTVFS; sqlite3_instvfs is "
     "unavailable", (char*)0);
  return TCL_ERROR;
}
#endif /* !defined(SQLITE_ENABLE_INSTVFS) */

int SqlitetestOsinst_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "sqlite3_instvfs", test_sqlite3_instvfs, 0, 0);
  return TCL_OK;
}

#endif /* SQLITE_TEST */








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******************************************************************************
**
** This file contains the implementation of an SQLite vfs wrapper that
** adds instrumentation to all vfs and file methods. C and Tcl interfaces
** are provided to control the instrumentation.
*/


/*
** This module contains code for a wrapper VFS that causes a log of
** all (well, technically "most") VFS calls to be written into a nominated
** file on disk. The log is stored in a compressed binary format to 
** reduce the amount of IO overhead introduced into the application


** by logging.


**
** The binary log files are read using a virtual table implementation

** also contained in this file. 

**

** CREATING LOG FILES:



**
**       int sqlite3_vfslog_new(

**         const char *zVfs,          // Name of new VFS
**         const char *zParentVfs,    // Name of parent VFS (or NULL)



**         const char *zLog           // Name of log file to write to



**       );
**
**       int sqlite3_vfslog_finalize(const char *zVfs);
**
** ANNOTATING LOG FILES:

**



**   To write an arbitrary message into a log file:
**
**       int sqlite3_vfslog_annotate(const char *zVfs, const char *zMsg);
**


** READING LOG FILES:
**
**   Log files are read using the "vfslog" virtual table implementation
**   in this file. To register the virtual table with SQLite, use:
**


**       int sqlite3_vfslog_register(sqlite3 *db);
**
**   Then, if the log file is named "vfs.log", the following SQL command:
**


**       CREATE VIRTUAL TABLE v USING vfslog('vfs.log');
**
**   creates a virtual table with 6 columns, as follows:
**
**       CREATE TABLE v(
**         event    TEXT,             // "xOpen", "xRead" etc.
**         file     TEXT,             // Name of file this call applies to
**         clicks   INTEGER,          // Time spent in call
**         rc       INTEGER,          // Return value
**         size     INTEGER,          // Bytes read or written
**         offset   INTEGER           // File offset read or written
**       );
*/

#include "sqlite3.h"
#include <string.h>
#include <assert.h>


/*
** Maximum pathname length supported by the vfslog backend.
*/
#define INST_MAX_PATHNAME 512




#define OS_ACCESS            1
#define OS_CHECKRESERVEDLOCK 2
#define OS_CLOSE             3
#define OS_CURRENTTIME       4
#define OS_DELETE            5
#define OS_DEVCHAR           6
#define OS_FILECONTROL       7
#define OS_FILESIZE          8
#define OS_FULLPATHNAME      9
#define OS_LOCK              11
#define OS_OPEN              12
#define OS_RANDOMNESS        13
#define OS_READ              14 
#define OS_SECTORSIZE        15
#define OS_SLEEP             16
#define OS_SYNC              17
#define OS_TRUNCATE          18
#define OS_UNLOCK            19
#define OS_WRITE             20
#define OS_SHMOPEN           21
#define OS_SHMCLOSE          22
#define OS_SHMGET            23
#define OS_SHMRELEASE        24
#define OS_SHMLOCK           25
#define OS_SHMSIZE           26
#define OS_ANNOTATE          27

#define OS_NUMEVENTS         28

#define VFSLOG_BUFFERSIZE 8192





typedef struct VfslogVfs VfslogVfs;
typedef struct VfslogFile VfslogFile;

struct VfslogVfs {
  sqlite3_vfs base;               /* VFS methods */
  sqlite3_vfs *pVfs;              /* Parent VFS */
  int iNextFileId;                /* Next file id */



  sqlite3_file *pLog;             /* Log file handle */

  sqlite3_int64 iOffset;          /* Log file offset of start of write buffer */

  int nBuf;                       /* Number of valid bytes in aBuf[] */
  char aBuf[VFSLOG_BUFFERSIZE];   /* Write buffer */
};

struct VfslogFile {
  sqlite3_file base;              /* IO methods */
  sqlite3_file *pReal;            /* Underlying file handle */
  sqlite3_vfs *pVfslog;           /* Associated VsflogVfs object */
  int iFileId;                    /* File id number */
};


#define REALVFS(p) (((VfslogVfs *)(p))->pVfs)











/*
** Method declarations for vfslog_file.
*/
static int vfslogClose(sqlite3_file*);
static int vfslogRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int vfslogWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
static int vfslogTruncate(sqlite3_file*, sqlite3_int64 size);
static int vfslogSync(sqlite3_file*, int flags);
static int vfslogFileSize(sqlite3_file*, sqlite3_int64 *pSize);
static int vfslogLock(sqlite3_file*, int);
static int vfslogUnlock(sqlite3_file*, int);
static int vfslogCheckReservedLock(sqlite3_file*, int *pResOut);
static int vfslogFileControl(sqlite3_file*, int op, void *pArg);
static int vfslogSectorSize(sqlite3_file*);
static int vfslogDeviceCharacteristics(sqlite3_file*);

static int vfslogShmOpen(sqlite3_file *pFile);
static int vfslogShmSize(sqlite3_file *pFile, int reqSize, int *pNewSize);
static int vfslogShmGet(sqlite3_file *pFile, int req, int *pSize, void **pp);
static int vfslogShmRelease(sqlite3_file *pFile);
static int vfslogShmLock(sqlite3_file *pFile, int desiredLock, int *gotLock);
static int vfslogShmClose(sqlite3_file *pFile, int deleteFlag);

/*
** Method declarations for vfslog_vfs.
*/
static int vfslogOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
static int vfslogDelete(sqlite3_vfs*, const char *zName, int syncDir);
static int vfslogAccess(sqlite3_vfs*, const char *zName, int flags, int *);
static int vfslogFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
static void *vfslogDlOpen(sqlite3_vfs*, const char *zFilename);
static void vfslogDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
static void (*vfslogDlSym(sqlite3_vfs *pVfs, void *p, const char*zSym))(void);
static void vfslogDlClose(sqlite3_vfs*, void*);
static int vfslogRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int vfslogSleep(sqlite3_vfs*, int microseconds);
static int vfslogCurrentTime(sqlite3_vfs*, double*);



static sqlite3_vfs vfslog_vfs = {
  1,                              /* iVersion */
  sizeof(VfslogFile),             /* szOsFile */
  INST_MAX_PATHNAME,              /* mxPathname */
  0,                              /* pNext */
  0,                              /* zName */
  0,                              /* pAppData */
  vfslogOpen,                     /* xOpen */
  vfslogDelete,                   /* xDelete */
  vfslogAccess,                   /* xAccess */
  vfslogFullPathname,             /* xFullPathname */
  vfslogDlOpen,                   /* xDlOpen */
  vfslogDlError,                  /* xDlError */
  vfslogDlSym,                    /* xDlSym */
  vfslogDlClose,                  /* xDlClose */
  vfslogRandomness,               /* xRandomness */
  vfslogSleep,                    /* xSleep */
  vfslogCurrentTime,              /* xCurrentTime */
};

static sqlite3_io_methods vfslog_io_methods = {
  2,                              /* iVersion */
  vfslogClose,                    /* xClose */
  vfslogRead,                     /* xRead */
  vfslogWrite,                    /* xWrite */
  vfslogTruncate,                 /* xTruncate */
  vfslogSync,                     /* xSync */
  vfslogFileSize,                 /* xFileSize */
  vfslogLock,                     /* xLock */
  vfslogUnlock,                   /* xUnlock */
  vfslogCheckReservedLock,        /* xCheckReservedLock */
  vfslogFileControl,              /* xFileControl */
  vfslogSectorSize,               /* xSectorSize */
  vfslogDeviceCharacteristics,    /* xDeviceCharacteristics */

  vfslogShmOpen,                  /* xShmOpen */





  vfslogShmSize,                  /* xShmSize */
  vfslogShmGet,                   /* xShmGet */
  vfslogShmRelease,               /* xShmRelease */
  vfslogShmLock,                  /* xShmLock */
  vfslogShmClose                  /* xShmClose */
};

#if defined(SQLITE_OS_UNIX) && !defined(NO_GETTOD)
#include <sys/time.h>
static sqlite3_uint64 vfslog_time(){
  struct timeval sTime;

  gettimeofday(&sTime, 0);




  return sTime.tv_usec + (sqlite3_uint64)sTime.tv_sec * 1000000;
}
#else
static sqlite3_uint64 vfslog_time(){
  return 0;
}
#endif



static void vfslog_call(sqlite3_vfs *, int, int, int, int, int, int);

static void vfslog_string(sqlite3_vfs *, const char *);








/*
** Close an vfslog-file.
*/
static int vfslogClose(sqlite3_file *pFile){
  sqlite3_uint64 t;
  int rc = SQLITE_OK;
  VfslogFile *p = (VfslogFile *)pFile;

  t = vfslog_time();
  if( p->pReal->pMethods ){
    rc = p->pReal->pMethods->xClose(p->pReal);
  }
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_CLOSE, p->iFileId, t, rc, 0, 0);
  return rc;
}

/*
** Read data from an vfslog-file.
*/
static int vfslogRead(
  sqlite3_file *pFile, 
  void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;

  t = vfslog_time();
  rc = p->pReal->pMethods->xRead(p->pReal, zBuf, iAmt, iOfst);

  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_READ, p->iFileId, t, rc, iAmt, (int)iOfst);
  return rc;
}

/*
** Write data to an vfslog-file.
*/
static int vfslogWrite(
  sqlite3_file *pFile,
  const void *z,
  int iAmt,
  sqlite_int64 iOfst
){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();

  rc = p->pReal->pMethods->xWrite(p->pReal, z, iAmt, iOfst);

  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_WRITE, p->iFileId, t, rc, iAmt, (int)iOfst);
  return rc;
}

/*
** Truncate an vfslog-file.
*/
static int vfslogTruncate(sqlite3_file *pFile, sqlite_int64 size){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xTruncate(p->pReal, size);

  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_TRUNCATE, p->iFileId, t, rc, 0, (int)size);
  return rc;
}

/*
** Sync an vfslog-file.
*/
static int vfslogSync(sqlite3_file *pFile, int flags){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xSync(p->pReal, flags);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_SYNC, p->iFileId, t, rc, flags, 0);
  return rc;
}

/*
** Return the current file-size of an vfslog-file.
*/
static int vfslogFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xFileSize(p->pReal, pSize);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_FILESIZE, p->iFileId, t, rc, 0, (int)*pSize);
  return rc;
}

/*
** Lock an vfslog-file.
*/
static int vfslogLock(sqlite3_file *pFile, int eLock){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xLock(p->pReal, eLock);

  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_LOCK, p->iFileId, t, rc, eLock, 0);
  return rc;
}

/*
** Unlock an vfslog-file.
*/
static int vfslogUnlock(sqlite3_file *pFile, int eLock){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xUnlock(p->pReal, eLock);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_UNLOCK, p->iFileId, t, rc, eLock, 0);
  return rc;
}

/*
** Check if another file-handle holds a RESERVED lock on an vfslog-file.
*/
static int vfslogCheckReservedLock(sqlite3_file *pFile, int *pResOut){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xCheckReservedLock(p->pReal, pResOut);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_CHECKRESERVEDLOCK, p->iFileId, t, rc, *pResOut, 0);
  return rc;
}

/*
** File control method. For custom operations on an vfslog-file.
*/
static int vfslogFileControl(sqlite3_file *pFile, int op, void *pArg){
  VfslogFile *p = (VfslogFile *)pFile;
  return p->pReal->pMethods->xFileControl(p->pReal, op, pArg);
}

/*

** Return the sector-size in bytes for an vfslog-file.
*/
static int vfslogSectorSize(sqlite3_file *pFile){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xSectorSize(p->pReal);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_SECTORSIZE, p->iFileId, t, rc, 0, 0);
  return rc;
}

/*

** Return the device characteristic flags supported by an vfslog-file.
*/
static int vfslogDeviceCharacteristics(sqlite3_file *pFile){

  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xDeviceCharacteristics(p->pReal);

  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_DEVCHAR, p->iFileId, t, rc, 0, 0);
  return rc;
}




static int vfslogShmOpen(sqlite3_file *pFile){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xShmOpen(p->pReal);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_SHMOPEN, p->iFileId, t, rc, 0, 0);
  return rc;
}
static int vfslogShmSize(sqlite3_file *pFile, int reqSize, int *pNewSize){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xShmSize(p->pReal, reqSize, pNewSize);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_SHMSIZE, p->iFileId, t, rc, 0, 0);
  return rc;
}

static int vfslogShmGet(sqlite3_file *pFile, int req, int *pSize, void **pp){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xShmGet(p->pReal, req, pSize, pp);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_SHMGET, p->iFileId, t, rc, 0, 0);
  return rc;

}
static int vfslogShmRelease(sqlite3_file *pFile){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xShmRelease(p->pReal);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_SHMRELEASE, p->iFileId, t, rc, 0, 0);
  return rc;
}
static int vfslogShmLock(sqlite3_file *pFile, int desiredLock, int *gotLock){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xShmLock(p->pReal, desiredLock, gotLock);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_SHMLOCK, p->iFileId, t, rc, 0, 0);
  return rc;
}



static int vfslogShmClose(sqlite3_file *pFile, int deleteFlag){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  t = vfslog_time();
  rc = p->pReal->pMethods->xShmClose(p->pReal, deleteFlag);
  t = vfslog_time() - t;
  vfslog_call(p->pVfslog, OS_SHMCLOSE, p->iFileId, t, rc, 0, 0);
  return rc;
}


/*
** Open an vfslog file handle.
*/
static int vfslogOpen(
  sqlite3_vfs *pVfs,
  const char *zName,
  sqlite3_file *pFile,
  int flags,
  int *pOutFlags
){
  int rc;
  sqlite3_uint64 t;
  VfslogFile *p = (VfslogFile *)pFile;
  VfslogVfs *pLog = (VfslogVfs *)pVfs;

  pFile->pMethods = &vfslog_io_methods;
  p->pReal = (sqlite3_file *)&p[1];

  p->pVfslog = pVfs;

  p->iFileId = ++pLog->iNextFileId;

  t = vfslog_time();

  rc = REALVFS(pVfs)->xOpen(REALVFS(pVfs), zName, p->pReal, flags, pOutFlags);
  t = vfslog_time() - t;

  vfslog_call(pVfs, OS_OPEN, p->iFileId, t, rc, 0, 0);
  vfslog_string(pVfs, zName);
  return rc;
}

/*
** Delete the file located at zPath. If the dirSync argument is true,
** ensure the file-system modifications are synced to disk before
** returning.
*/
static int vfslogDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  int rc;
  sqlite3_uint64 t;
  t = vfslog_time();

  rc = REALVFS(pVfs)->xDelete(REALVFS(pVfs), zPath, dirSync);
  t = vfslog_time() - t;
  vfslog_call(pVfs, OS_DELETE, 0, t, rc, dirSync, 0);
  vfslog_string(pVfs, zPath);
  return rc;
}

/*
** Test for access permissions. Return true if the requested permission
** is available, or false otherwise.
*/
static int vfslogAccess(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int flags, 
  int *pResOut
){
  int rc;
  sqlite3_uint64 t;
  t = vfslog_time();

  rc = REALVFS(pVfs)->xAccess(REALVFS(pVfs), zPath, flags, pResOut);
  t = vfslog_time() - t;
  vfslog_call(pVfs, OS_ACCESS, 0, t, rc, flags, *pResOut);
  vfslog_string(pVfs, zPath);
  return rc;
}

/*
** Populate buffer zOut with the full canonical pathname corresponding
** to the pathname in zPath. zOut is guaranteed to point to a buffer
** of at least (INST_MAX_PATHNAME+1) bytes.
*/
static int vfslogFullPathname(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int nOut, 
  char *zOut
){

  return REALVFS(pVfs)->xFullPathname(REALVFS(pVfs), zPath, nOut, zOut);

}

/*
** Open the dynamic library located at zPath and return a handle.
*/
static void *vfslogDlOpen(sqlite3_vfs *pVfs, const char *zPath){
  return REALVFS(pVfs)->xDlOpen(REALVFS(pVfs), zPath);
}

/*
** Populate the buffer zErrMsg (size nByte bytes) with a human readable
** utf-8 string describing the most recent error encountered associated 
** with dynamic libraries.
*/
static void vfslogDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
  REALVFS(pVfs)->xDlError(REALVFS(pVfs), nByte, zErrMsg);
}

/*
** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
*/
static void (*vfslogDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
  return REALVFS(pVfs)->xDlSym(REALVFS(pVfs), p, zSym);
}

/*
** Close the dynamic library handle pHandle.
*/
static void vfslogDlClose(sqlite3_vfs *pVfs, void *pHandle){
  REALVFS(pVfs)->xDlClose(REALVFS(pVfs), pHandle);
}

/*
** Populate the buffer pointed to by zBufOut with nByte bytes of 
** random data.
*/
static int vfslogRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){

  return REALVFS(pVfs)->xRandomness(REALVFS(pVfs), nByte, zBufOut);

}

/*
** Sleep for nMicro microseconds. Return the number of microseconds 
** actually slept.
*/
static int vfslogSleep(sqlite3_vfs *pVfs, int nMicro){

  return REALVFS(pVfs)->xSleep(REALVFS(pVfs), nMicro);

}

/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int vfslogCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){

  return REALVFS(pVfs)->xCurrentTime(REALVFS(pVfs), pTimeOut);

}





static void vfslog_flush(VfslogVfs *p){





































































































































#ifdef SQLITE_TEST
  extern int sqlite3_io_error_pending;
  extern int sqlite3_io_error_persist;
  extern int sqlite3_diskfull_pending;

  int pending = sqlite3_io_error_pending;
  int persist = sqlite3_io_error_persist;
  int diskfull = sqlite3_diskfull_pending;

  sqlite3_io_error_pending = 0;
  sqlite3_io_error_persist = 0;
  sqlite3_diskfull_pending = 0;
#endif

  if( p->nBuf ){
    p->pLog->pMethods->xWrite(p->pLog, p->aBuf, p->nBuf, p->iOffset);
    p->iOffset += p->nBuf;
    p->nBuf = 0;
  }

#ifdef SQLITE_TEST
  sqlite3_io_error_pending = pending;
  sqlite3_io_error_persist = persist;
  sqlite3_diskfull_pending = diskfull;
#endif
}













static void put32bits(unsigned char *p, unsigned int v){




  p[0] = v>>24;



  p[1] = v>>16;
  p[2] = v>>8;

  p[3] = v;
}
















static void vfslog_call(
  sqlite3_vfs *pVfs,
  int eEvent,
  int iFileid,
  int nClick,
  int return_code,
  int size,
  int offset
){

  VfslogVfs *p = (VfslogVfs *)pVfs;
  unsigned char *zRec;
  if( (24+p->nBuf)>sizeof(p->aBuf) ){
    vfslog_flush(p);
  }

  zRec = (unsigned char *)&p->aBuf[p->nBuf];
  put32bits(&zRec[0], eEvent);
  put32bits(&zRec[4], iFileid);
  put32bits(&zRec[8], nClick);
  put32bits(&zRec[12], return_code);
  put32bits(&zRec[16], size);
  put32bits(&zRec[20], offset);
  p->nBuf += 24;
}


static void vfslog_string(sqlite3_vfs *pVfs, const char *zStr){
  VfslogVfs *p = (VfslogVfs *)pVfs;
  unsigned char *zRec;
  int nStr = zStr ? strlen(zStr) : 0;
  if( (4+nStr+p->nBuf)>sizeof(p->aBuf) ){
    vfslog_flush(p);
  }
  zRec = (unsigned char *)&p->aBuf[p->nBuf];
  put32bits(&zRec[0], nStr);
  if( zStr ){

    memcpy(&zRec[4], zStr, nStr);
  }
  p->nBuf += (4 + nStr);
}

static void vfslog_finalize(VfslogVfs *p){
  if( p->pLog->pMethods ){
    vfslog_flush(p);
    p->pLog->pMethods->xClose(p->pLog);
  }
  sqlite3_free(p);
}

int sqlite3_vfslog_finalize(const char *zVfs){
  sqlite3_vfs *pVfs;




  pVfs = sqlite3_vfs_find(zVfs);
  if( !pVfs || pVfs->xOpen!=vfslogOpen ){
    return SQLITE_ERROR;
  } 
  sqlite3_vfs_unregister(pVfs);
  vfslog_finalize((VfslogVfs *)pVfs);
  return SQLITE_OK;
}


int sqlite3_vfslog_new(



  const char *zVfs,               /* New VFS name */
  const char *zParentVfs,         /* Parent VFS name (or NULL) */
  const char *zLog                /* Log file name */
){


  VfslogVfs *p;
























  sqlite3_vfs *pParent;
  int nByte;
  int flags;
  int rc;
  char *zFile;
  int nVfs;

  pParent = sqlite3_vfs_find(zParentVfs);
  if( !pParent ){
    return SQLITE_ERROR;
  }

  nVfs = strlen(zVfs);
  nByte = sizeof(VfslogVfs) + pParent->szOsFile + nVfs+1+pParent->mxPathname+1;
  p = (VfslogVfs *)sqlite3_malloc(nByte);
  memset(p, 0, nByte);

  p->pVfs = pParent;
  p->pLog = (sqlite3_file *)&p[1];
  memcpy(&p->base, &vfslog_vfs, sizeof(sqlite3_vfs));
  p->base.zName = &((char *)p->pLog)[pParent->szOsFile];
  p->base.szOsFile += pParent->szOsFile;
  memcpy((char *)p->base.zName, zVfs, nVfs);

  zFile = (char *)&p->base.zName[nVfs+1];
  pParent->xFullPathname(pParent, zLog, pParent->mxPathname, zFile);

  flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MASTER_JOURNAL;
  pParent->xDelete(pParent, zFile, 0);
  rc = pParent->xOpen(pParent, zFile, p->pLog, flags, &flags);
  if( rc==SQLITE_OK ){
    memcpy(p->aBuf, "sqlite_ostrace1.....", 20);
    p->iOffset = 0;
    p->nBuf = 20;
    rc = sqlite3_vfs_register((sqlite3_vfs *)p, 1);
  }
  if( rc ){
    vfslog_finalize(p);
  }
  return rc;
}

int sqlite3_vfslog_annotate(const char *zVfs, const char *zMsg){
  sqlite3_vfs *pVfs;
  pVfs = sqlite3_vfs_find(zVfs);
  if( !pVfs || pVfs->xOpen!=vfslogOpen ){
    return SQLITE_ERROR;
  } 
  vfslog_call(pVfs, OS_ANNOTATE, 0, 0, 0, 0, 0);
  vfslog_string(pVfs, zMsg);
  return SQLITE_OK;
}

static const char *vfslog_eventname(int eEvent){
  const char *zEvent = 0;

  switch( eEvent ){
    case OS_CLOSE:             zEvent = "xClose"; break;
    case OS_READ:              zEvent = "xRead"; break;
    case OS_WRITE:             zEvent = "xWrite"; break;
    case OS_TRUNCATE:          zEvent = "xTruncate"; break;
    case OS_SYNC:              zEvent = "xSync"; break;
    case OS_FILESIZE:          zEvent = "xFilesize"; break;
    case OS_LOCK:              zEvent = "xLock"; break;
    case OS_UNLOCK:            zEvent = "xUnlock"; break;
    case OS_CHECKRESERVEDLOCK: zEvent = "xCheckResLock"; break;
    case OS_FILECONTROL:       zEvent = "xFileControl"; break;
    case OS_SECTORSIZE:        zEvent = "xSectorSize"; break;
    case OS_DEVCHAR:           zEvent = "xDeviceChar"; break;
    case OS_OPEN:              zEvent = "xOpen"; break;
    case OS_DELETE:            zEvent = "xDelete"; break;
    case OS_ACCESS:            zEvent = "xAccess"; break;
    case OS_FULLPATHNAME:      zEvent = "xFullPathname"; break;
    case OS_RANDOMNESS:        zEvent = "xRandomness"; break;
    case OS_SLEEP:             zEvent = "xSleep"; break;
    case OS_CURRENTTIME:       zEvent = "xCurrentTime"; break;

    case OS_SHMCLOSE:          zEvent = "xShmClose"; break;
    case OS_SHMOPEN:           zEvent = "xShmOpen"; break;
    case OS_SHMGET:            zEvent = "xShmGet"; break;
    case OS_SHMSIZE:           zEvent = "xShmSize"; break;
    case OS_SHMRELEASE:        zEvent = "xShmRelease"; break;
    case OS_SHMLOCK:           zEvent = "xShmLock"; break;

    case OS_ANNOTATE:          zEvent = "annotation"; break;
  }

  return zEvent;
}

typedef struct VfslogVtab VfslogVtab;
typedef struct VfslogCsr VfslogCsr;

/*
** Virtual table type for the vfslog reader module.
*/
struct VfslogVtab {
  sqlite3_vtab base;              /* Base class */
  sqlite3_file *pFd;              /* File descriptor open on vfslog file */
  sqlite3_int64 nByte;            /* Size of file in bytes */
  char *zFile;                    /* File name for pFd */
};

/*
** Virtual table cursor type for the vfslog reader module.
*/
struct VfslogCsr {
  sqlite3_vtab_cursor base;       /* Base class */
  sqlite3_int64 iRowid;           /* Current rowid. */
  sqlite3_int64 iOffset;          /* Offset of next record in file */
  char *zTransient;               /* Transient 'file' string */
  int nFile;                      /* Size of array azFile[] */
  char **azFile;                  /* File strings */
  unsigned char aBuf[1024];       /* Current vfs log entry (read from file) */
};

static unsigned int get32bits(unsigned char *p){
  return (p[0]<<24) + (p[1]<<16) + (p[2]<<8) + p[3];
}

/*
** The argument must point to a buffer containing a nul-terminated string.
** If the string begins with an SQL quote character it is overwritten by
** the dequoted version. Otherwise the buffer is left unmodified.
*/
static void dequote(char *z){
  char quote;                     /* Quote character (if any ) */
  quote = z[0];
  if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){
    int iIn = 1;                  /* Index of next byte to read from input */
    int iOut = 0;                 /* Index of next byte to write to output */
    if( quote=='[' ) quote = ']';  
    while( z[iIn] ){
      if( z[iIn]==quote ){
        if( z[iIn+1]!=quote ) break;
        z[iOut++] = quote;
        iIn += 2;
      }else{
        z[iOut++] = z[iIn++];
      }
    }
    z[iOut] = '\0';
  }
}

/*
** Connect to or create a vfslog virtual table.
*/
static int vlogConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  sqlite3_vfs *pVfs;              /* VFS used to read log file */
  int flags;                      /* flags passed to pVfs->xOpen() */
  VfslogVtab *p;
  int rc;
  int nByte;
  char *zFile;

  *ppVtab = 0;
  pVfs = sqlite3_vfs_find(0);
  nByte = sizeof(VfslogVtab) + pVfs->szOsFile + pVfs->mxPathname;
  p = sqlite3_malloc(nByte);
  if( p==0 ) return SQLITE_NOMEM;
  memset(p, 0, nByte);

  p->pFd = (sqlite3_file *)&p[1];
  p->zFile = &((char *)p->pFd)[pVfs->szOsFile];

  zFile = sqlite3_mprintf("%s", argv[3]);
  if( !zFile ){
    sqlite3_free(p);
    return SQLITE_NOMEM;
  }
  dequote(zFile);
  pVfs->xFullPathname(pVfs, zFile, pVfs->mxPathname, p->zFile);
  sqlite3_free(zFile);

  flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MASTER_JOURNAL;
  rc = pVfs->xOpen(pVfs, p->zFile, p->pFd, flags, &flags);

  if( rc==SQLITE_OK ){
    p->pFd->pMethods->xFileSize(p->pFd, &p->nByte);
    sqlite3_declare_vtab(db, 
        "CREATE TABLE xxx(event, file, click, rc, size, offset)"
    );
    *ppVtab = &p->base;
  }else{
    sqlite3_free(p);
  }

  return rc;
}

/*
** There is no "best-index". This virtual table always does a linear
** scan of the binary VFS log file.
*/
static int vlogBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
  pIdxInfo->estimatedCost = 10.0;
  return SQLITE_OK;
}

/*
** Disconnect from or destroy a vfslog virtual table.
*/
static int vlogDisconnect(sqlite3_vtab *pVtab){
  VfslogVtab *p = (VfslogVtab *)pVtab;
  if( p->pFd->pMethods ){
    p->pFd->pMethods->xClose(p->pFd);
    p->pFd->pMethods = 0;
  }
  sqlite3_free(p);
  return SQLITE_OK;
}

/*
** Open a new vfslog cursor.
*/
static int vlogOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  VfslogCsr *pCsr;                /* Newly allocated cursor object */

  pCsr = sqlite3_malloc(sizeof(VfslogCsr));
  if( !pCsr ) return SQLITE_NOMEM;
  memset(pCsr, 0, sizeof(VfslogCsr));
  *ppCursor = &pCsr->base;
  return SQLITE_OK;
}

/*
** Close a vfslog cursor.
*/
static int vlogClose(sqlite3_vtab_cursor *pCursor){
  VfslogCsr *p = (VfslogCsr *)pCursor;
  int i;
  for(i=0; i<p->nFile; i++){
    sqlite3_free(p->azFile[i]);
  }
  sqlite3_free(p->azFile);
  sqlite3_free(p->zTransient);
  sqlite3_free(p);
  return SQLITE_OK;
}

/*
** Move a vfslog cursor to the next entry in the file.
*/
static int vlogNext(sqlite3_vtab_cursor *pCursor){
  VfslogCsr *pCsr = (VfslogCsr *)pCursor;
  VfslogVtab *p = (VfslogVtab *)pCursor->pVtab;
  int rc = SQLITE_OK;
  int nRead;

  sqlite3_free(pCsr->zTransient);
  pCsr->zTransient = 0;

  nRead = 24;
  if( pCsr->iOffset+nRead<=p->nByte ){
    int eEvent;
    rc = p->pFd->pMethods->xRead(p->pFd, pCsr->aBuf, nRead, pCsr->iOffset);

    eEvent = get32bits(pCsr->aBuf);
    if( (rc==SQLITE_OK)
     && (eEvent==OS_OPEN || eEvent==OS_DELETE || eEvent==OS_ACCESS) 
    ){
      char buf[4];
      rc = p->pFd->pMethods->xRead(p->pFd, buf, 4, pCsr->iOffset+nRead);
      nRead += 4;
      if( rc==SQLITE_OK ){
        int nStr = get32bits((unsigned char *)buf);
        char *zStr = sqlite3_malloc(nStr+1);
        rc = p->pFd->pMethods->xRead(p->pFd, zStr, nStr, pCsr->iOffset+nRead);
        zStr[nStr] = '\0';
        nRead += nStr;

        if( eEvent==OS_OPEN ){
          int iFileid = get32bits(&pCsr->aBuf[4]);
          if( iFileid>=pCsr->nFile ){
            int nNew = sizeof(pCsr->azFile[0])*(iFileid+1);
            pCsr->azFile = (char **)sqlite3_realloc(pCsr->azFile, nNew);
            nNew -= sizeof(pCsr->azFile[0])*pCsr->nFile;
            memset(&pCsr->azFile[pCsr->nFile], 0, nNew);
            pCsr->nFile = iFileid+1;
          }
          sqlite3_free(pCsr->azFile[iFileid]);
          pCsr->azFile[iFileid] = zStr;
        }else{
          pCsr->zTransient = zStr;
        }
      }
    }
  }

  pCsr->iRowid += 1;
  pCsr->iOffset += nRead;
  return rc;
}

static int vlogEof(sqlite3_vtab_cursor *pCursor){
  VfslogCsr *pCsr = (VfslogCsr *)pCursor;
  VfslogVtab *p = (VfslogVtab *)pCursor->pVtab;
  return (pCsr->iOffset>=p->nByte);
}

static int vlogFilter(
  sqlite3_vtab_cursor *pCursor, 
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  VfslogCsr *pCsr = (VfslogCsr *)pCursor;
  pCsr->iRowid = 0;
  pCsr->iOffset = 20;
  return vlogNext(pCursor);
}

static int vlogColumn(
  sqlite3_vtab_cursor *pCursor, 
  sqlite3_context *ctx, 
  int i
){
  unsigned int val;
  VfslogCsr *pCsr = (VfslogCsr *)pCursor;

  assert( i<7 );
  val = get32bits(&pCsr->aBuf[4*i]);

  switch( i ){
    case 0: {
      sqlite3_result_text(ctx, vfslog_eventname(val), -1, SQLITE_STATIC);
      break;
    }
    case 1: {
      char *zStr = pCsr->zTransient;
      if( val!=0 && val<pCsr->nFile ){
        zStr = pCsr->azFile[val];
      }
      sqlite3_result_text(ctx, zStr, -1, SQLITE_TRANSIENT);
      break;
    }
    default:
      sqlite3_result_int(ctx, val);
      break;
  }

  return SQLITE_OK;
}

static int vlogRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
  VfslogCsr *pCsr = (VfslogCsr *)pCursor;
  *pRowid = pCsr->iRowid;
  return SQLITE_OK;
}

int sqlite3_vfslog_register(sqlite3 *db){
  static sqlite3_module vfslog_module = {
    0,                            /* iVersion */
    vlogConnect,                /* xCreate */
    vlogConnect,                /* xConnect */
    vlogBestIndex,              /* xBestIndex */
    vlogDisconnect,             /* xDisconnect */
    vlogDisconnect,             /* xDestroy */
    vlogOpen,                   /* xOpen - open a cursor */
    vlogClose,                  /* xClose - close a cursor */
    vlogFilter,                 /* xFilter - configure scan constraints */
    vlogNext,                   /* xNext - advance a cursor */
    vlogEof,                    /* xEof - check for end of scan */
    vlogColumn,                 /* xColumn - read data */
    vlogRowid,                  /* xRowid - read data */
    0,                            /* xUpdate */
    0,                            /* xBegin */
    0,                            /* xSync */
    0,                            /* xCommit */
    0,                            /* xRollback */
    0,                            /* xFindMethod */
    0,                            /* xRename */
  };

  sqlite3_create_module(db, "vfslog", &vfslog_module, 0);
  return SQLITE_OK;
}


/**************************************************************************
***************************************************************************
** Tcl interface starts here.
*/



#if defined(SQLITE_TEST) || defined(TCLSH)






















#include <tcl.h>




















static int test_vfslog(
  void *clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  struct SqliteDb { sqlite3 *db; };
  sqlite3 *db;
  Tcl_CmdInfo cmdInfo;
  int rc = SQLITE_ERROR;

  static const char *strs[] = { "annotate", "finalize", "new",  "register", 0 };

  enum VL_enum { VL_ANNOTATE, VL_FINALIZE, VL_NEW, VL_REGISTER };
  int iSub;

  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUB-COMMAND ...");
    return TCL_ERROR;
  }
  if( Tcl_GetIndexFromObj(interp, objv[1], strs, "sub-command", 0, &iSub) ){
    return TCL_ERROR;
  }

  switch( (enum VL_enum)iSub ){
    case VL_ANNOTATE: {
      int rc;
      char *zVfs;
      char *zMsg;

      if( objc!=4 ){



        Tcl_WrongNumArgs(interp, 3, objv, "VFS");
        return TCL_ERROR;
      }

      zVfs = Tcl_GetString(objv[2]);

      zMsg = Tcl_GetString(objv[3]);
      rc = sqlite3_vfslog_annotate(zVfs, zMsg);
      if( rc!=SQLITE_OK ){
        Tcl_AppendResult(interp, "failed", 0);
        return TCL_ERROR;























      }



      break;
    }

    case VL_FINALIZE: {













      int rc;





      char *zVfs;


      if( objc!=3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "VFS");
        return TCL_ERROR;
      }
      zVfs = Tcl_GetString(objv[2]);
      rc = sqlite3_vfslog_finalize(zVfs);
      if( rc!=SQLITE_OK ){
        Tcl_AppendResult(interp, "failed", 0);
        return TCL_ERROR;
      }


      break;
    };

    case VL_NEW: {
      int rc;
      char *zVfs;
      char *zParent;
      char *zLog;
      if( objc!=5 ){
        Tcl_WrongNumArgs(interp, 2, objv, "VFS PARENT LOGFILE");
        return TCL_ERROR;
      }
      zVfs = Tcl_GetString(objv[2]);

      zParent = Tcl_GetString(objv[3]);



      zLog = Tcl_GetString(objv[4]);












      if( *zParent=='\0' ) zParent = 0;



      rc = sqlite3_vfslog_new(zVfs, zParent, zLog);
      if( rc!=SQLITE_OK ){





        Tcl_AppendResult(interp, "failed", 0);
        return TCL_ERROR;
      }
      break;


    };






    case VL_REGISTER: {
      char *zDb;




      if( objc!=3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "DB");




        return TCL_ERROR;
      }

      zDb = Tcl_GetString(objv[2]);
      if( Tcl_GetCommandInfo(interp, zDb, &cmdInfo) ){

        db = ((struct SqliteDb*)cmdInfo.objClientData)->db;
        rc = sqlite3_vfslog_register(db);
      }

      if( rc!=SQLITE_OK ){
        Tcl_AppendResult(interp, "Bad sqlite3 handle: ", zDb, 0);
        return TCL_ERROR;


      }







      break;
    };
  }





  return TCL_OK;
}


int SqlitetestOsinst_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "vfslog", test_vfslog, 0, 0);
  return TCL_OK;
}

#endif /* SQLITE_TEST */

Changes to src/test_vfs.c.
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**
*/
#if SQLITE_TEST          /* This file is used for testing only */

#include "sqlite3.h"
#include "sqliteInt.h"

typedef struct tvfs_file tvfs_file;
struct tvfs_file {
  sqlite3_file base;
  sqlite3_file *pReal;
};

typedef struct Testvfs Testvfs;
typedef struct TestvfsShm TestvfsShm;
typedef struct TestvfsBuffer TestvfsBuffer;















/*
** An instance of this structure is allocated for each VFS created. The
** sqlite3_vfs.pAppData field of the VFS structure registered with SQLite
** is set to point to it.
*/
struct Testvfs {
  char *zName;                    /* Name of this VFS */
  sqlite3_vfs *pParent;           /* The VFS to use for file IO */
  sqlite3_vfs *pVfs;              /* The testvfs registered with SQLite */
  Tcl_Interp *interp;             /* Interpreter to run script in */
  int nScript;                    /* Number of elements in array apScript */
  Tcl_Obj **apScript;             /* Script to execute */
  TestvfsBuffer *pBuffer;         /* List of shared buffers */

};

/*
** A shared-memory buffer.
*/
struct TestvfsBuffer {
  char *zFile;                    /* Associated file name */
  int n;                          /* Size of allocated buffer in bytes */
  u8 *a;                          /* Buffer allocated using ckalloc() */
  int nRef;                       /* Number of references to this object */
  TestvfsBuffer *pNext;           /* Next in linked list of all buffers */
};

/*
** A shared-memory handle returned by tvfsShmOpen().
*/
struct TestvfsShm {
  Tcl_Obj *id;                    /* Name of this handle */
  TestvfsBuffer *pBuffer;         /* Underlying buffer */
};


#define PARENTVFS(x) (((Testvfs *)((x)->pAppData))->pParent)


/*
** Method declarations for tvfs_file.
*/
static int tvfsClose(sqlite3_file*);
static int tvfsRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int tvfsWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
static int tvfsTruncate(sqlite3_file*, sqlite3_int64 size);
static int tvfsSync(sqlite3_file*, int flags);
static int tvfsFileSize(sqlite3_file*, sqlite3_int64 *pSize);







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**
*/
#if SQLITE_TEST          /* This file is used for testing only */

#include "sqlite3.h"
#include "sqliteInt.h"







typedef struct Testvfs Testvfs;
typedef struct TestvfsShm TestvfsShm;
typedef struct TestvfsBuffer TestvfsBuffer;
typedef struct TestvfsFile TestvfsFile;

/*
** An open file handle.
*/
struct TestvfsFile {
  sqlite3_file base;              /* Base class.  Must be first */
  sqlite3_vfs *pVfs;              /* The VFS */
  const char *zFilename;          /* Filename as passed to xOpen() */
  sqlite3_file *pReal;            /* The real, underlying file descriptor */
  Tcl_Obj *pShmId;                /* Shared memory id for Tcl callbacks */
  TestvfsBuffer *pShm;            /* Shared memory buffer */
};


/*
** An instance of this structure is allocated for each VFS created. The
** sqlite3_vfs.pAppData field of the VFS structure registered with SQLite
** is set to point to it.
*/
struct Testvfs {
  char *zName;                    /* Name of this VFS */
  sqlite3_vfs *pParent;           /* The VFS to use for file IO */
  sqlite3_vfs *pVfs;              /* The testvfs registered with SQLite */
  Tcl_Interp *interp;             /* Interpreter to run script in */
  int nScript;                    /* Number of elements in array apScript */
  Tcl_Obj **apScript;             /* Script to execute */
  TestvfsBuffer *pBuffer;         /* List of shared buffers */
  int isNoshm;
};

/*
** A shared-memory buffer.
*/
struct TestvfsBuffer {
  char *zFile;                    /* Associated file name */
  int n;                          /* Size of allocated buffer in bytes */
  u8 *a;                          /* Buffer allocated using ckalloc() */
  int nRef;                       /* Number of references to this object */
  TestvfsBuffer *pNext;           /* Next in linked list of all buffers */
};










#define PARENTVFS(x) (((Testvfs *)((x)->pAppData))->pParent)


/*
** Method declarations for TestvfsFile.
*/
static int tvfsClose(sqlite3_file*);
static int tvfsRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int tvfsWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
static int tvfsTruncate(sqlite3_file*, sqlite3_int64 size);
static int tvfsSync(sqlite3_file*, int flags);
static int tvfsFileSize(sqlite3_file*, sqlite3_int64 *pSize);
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static void (*tvfsDlSym(sqlite3_vfs*,void*, const char *zSymbol))(void);
static void tvfsDlClose(sqlite3_vfs*, void*);
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
static int tvfsRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int tvfsSleep(sqlite3_vfs*, int microseconds);
static int tvfsCurrentTime(sqlite3_vfs*, double*);

static int tvfsShmOpen(sqlite3_vfs *, const char *, sqlite3_shm **);
static int tvfsShmSize(sqlite3_vfs*, sqlite3_shm *, int , int *);
static int tvfsShmGet(sqlite3_vfs*, sqlite3_shm *, int , int *, void **);
static int tvfsShmRelease(sqlite3_vfs*, sqlite3_shm *);
static int tvfsShmLock(sqlite3_vfs*, sqlite3_shm *, int , int *);
static int tvfsShmClose(sqlite3_vfs*, sqlite3_shm *, int);

static sqlite3_io_methods tvfs_io_methods = {
  1,                            /* iVersion */
  tvfsClose,                      /* xClose */
  tvfsRead,                       /* xRead */
  tvfsWrite,                      /* xWrite */
  tvfsTruncate,                   /* xTruncate */
  tvfsSync,                       /* xSync */
  tvfsFileSize,                   /* xFileSize */
  tvfsLock,                       /* xLock */
  tvfsUnlock,                     /* xUnlock */
  tvfsCheckReservedLock,          /* xCheckReservedLock */
  tvfsFileControl,                /* xFileControl */
  tvfsSectorSize,                 /* xSectorSize */
  tvfsDeviceCharacteristics       /* xDeviceCharacteristics */






};

/*
** Close an tvfs-file.
*/
static int tvfsClose(sqlite3_file *pFile){
  tvfs_file *p = (tvfs_file *)pFile;







  return sqlite3OsClose(p->pReal);
}

/*
** Read data from an tvfs-file.
*/
static int tvfsRead(
  sqlite3_file *pFile, 
  void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsRead(p->pReal, zBuf, iAmt, iOfst);
}

/*
** Write data to an tvfs-file.
*/
static int tvfsWrite(
  sqlite3_file *pFile, 
  const void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsWrite(p->pReal, zBuf, iAmt, iOfst);
}

/*
** Truncate an tvfs-file.
*/
static int tvfsTruncate(sqlite3_file *pFile, sqlite_int64 size){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsTruncate(p->pReal, size);
}

/*
** Sync an tvfs-file.
*/
static int tvfsSync(sqlite3_file *pFile, int flags){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsSync(p->pReal, flags);
}

/*
** Return the current file-size of an tvfs-file.
*/
static int tvfsFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsFileSize(p->pReal, pSize);
}

/*
** Lock an tvfs-file.
*/
static int tvfsLock(sqlite3_file *pFile, int eLock){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsLock(p->pReal, eLock);
}

/*
** Unlock an tvfs-file.
*/
static int tvfsUnlock(sqlite3_file *pFile, int eLock){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsUnlock(p->pReal, eLock);
}

/*
** Check if another file-handle holds a RESERVED lock on an tvfs-file.
*/
static int tvfsCheckReservedLock(sqlite3_file *pFile, int *pResOut){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsCheckReservedLock(p->pReal, pResOut);
}

/*
** File control method. For custom operations on an tvfs-file.
*/
static int tvfsFileControl(sqlite3_file *pFile, int op, void *pArg){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsFileControl(p->pReal, op, pArg);
}

/*
** Return the sector-size in bytes for an tvfs-file.
*/
static int tvfsSectorSize(sqlite3_file *pFile){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsSectorSize(p->pReal);
}

/*
** Return the device characteristic flags supported by an tvfs-file.
*/
static int tvfsDeviceCharacteristics(sqlite3_file *pFile){
  tvfs_file *p = (tvfs_file *)pFile;
  return sqlite3OsDeviceCharacteristics(p->pReal);
}

/*
** Open an tvfs file handle.
*/
static int tvfsOpen(
  sqlite3_vfs *pVfs,
  const char *zName,
  sqlite3_file *pFile,
  int flags,
  int *pOutFlags
){
  int rc;
  tvfs_file *p = (tvfs_file *)pFile;




  p->pReal = (sqlite3_file *)&p[1];
  rc = sqlite3OsOpen(PARENTVFS(pVfs), zName, p->pReal, flags, pOutFlags);
  if( p->pReal->pMethods ){











    pFile->pMethods = &tvfs_io_methods;
  }

  return rc;
}

/*
** Delete the file located at zPath. If the dirSync argument is true,
** ensure the file-system modifications are synced to disk before
** returning.







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static void (*tvfsDlSym(sqlite3_vfs*,void*, const char *zSymbol))(void);
static void tvfsDlClose(sqlite3_vfs*, void*);
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
static int tvfsRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int tvfsSleep(sqlite3_vfs*, int microseconds);
static int tvfsCurrentTime(sqlite3_vfs*, double*);

static int tvfsShmOpen(sqlite3_file*);
static int tvfsShmSize(sqlite3_file*, int , int *);
static int tvfsShmGet(sqlite3_file*, int , int *, void **);
static int tvfsShmRelease(sqlite3_file*);
static int tvfsShmLock(sqlite3_file*, int , int *);
static int tvfsShmClose(sqlite3_file*, int);

static sqlite3_io_methods tvfs_io_methods = {
  2,                            /* iVersion */
  tvfsClose,                      /* xClose */
  tvfsRead,                       /* xRead */
  tvfsWrite,                      /* xWrite */
  tvfsTruncate,                   /* xTruncate */
  tvfsSync,                       /* xSync */
  tvfsFileSize,                   /* xFileSize */
  tvfsLock,                       /* xLock */
  tvfsUnlock,                     /* xUnlock */
  tvfsCheckReservedLock,          /* xCheckReservedLock */
  tvfsFileControl,                /* xFileControl */
  tvfsSectorSize,                 /* xSectorSize */
  tvfsDeviceCharacteristics,      /* xDeviceCharacteristics */
  tvfsShmOpen,                    /* xShmOpen */
  tvfsShmSize,                    /* xShmSize */
  tvfsShmGet,                     /* xShmGet */
  tvfsShmRelease,                 /* xShmRelease */
  tvfsShmLock,                    /* xShmLock */
  tvfsShmClose                    /* xShmClose */
};

/*
** Close an tvfs-file.
*/
static int tvfsClose(sqlite3_file *pFile){
  TestvfsFile *p = (TestvfsFile *)pFile;
  if( p->pShmId ){
    Tcl_DecrRefCount(p->pShmId);
    p->pShmId = 0;
  }
  if( pFile->pMethods ){
    ckfree((char *)pFile->pMethods);
  }
  return sqlite3OsClose(p->pReal);
}

/*
** Read data from an tvfs-file.
*/
static int tvfsRead(
  sqlite3_file *pFile, 
  void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsRead(p->pReal, zBuf, iAmt, iOfst);
}

/*
** Write data to an tvfs-file.
*/
static int tvfsWrite(
  sqlite3_file *pFile, 
  const void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsWrite(p->pReal, zBuf, iAmt, iOfst);
}

/*
** Truncate an tvfs-file.
*/
static int tvfsTruncate(sqlite3_file *pFile, sqlite_int64 size){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsTruncate(p->pReal, size);
}

/*
** Sync an tvfs-file.
*/
static int tvfsSync(sqlite3_file *pFile, int flags){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsSync(p->pReal, flags);
}

/*
** Return the current file-size of an tvfs-file.
*/
static int tvfsFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsFileSize(p->pReal, pSize);
}

/*
** Lock an tvfs-file.
*/
static int tvfsLock(sqlite3_file *pFile, int eLock){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsLock(p->pReal, eLock);
}

/*
** Unlock an tvfs-file.
*/
static int tvfsUnlock(sqlite3_file *pFile, int eLock){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsUnlock(p->pReal, eLock);
}

/*
** Check if another file-handle holds a RESERVED lock on an tvfs-file.
*/
static int tvfsCheckReservedLock(sqlite3_file *pFile, int *pResOut){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsCheckReservedLock(p->pReal, pResOut);
}

/*
** File control method. For custom operations on an tvfs-file.
*/
static int tvfsFileControl(sqlite3_file *pFile, int op, void *pArg){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsFileControl(p->pReal, op, pArg);
}

/*
** Return the sector-size in bytes for an tvfs-file.
*/
static int tvfsSectorSize(sqlite3_file *pFile){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsSectorSize(p->pReal);
}

/*
** Return the device characteristic flags supported by an tvfs-file.
*/
static int tvfsDeviceCharacteristics(sqlite3_file *pFile){
  TestvfsFile *p = (TestvfsFile *)pFile;
  return sqlite3OsDeviceCharacteristics(p->pReal);
}

/*
** Open an tvfs file handle.
*/
static int tvfsOpen(
  sqlite3_vfs *pVfs,
  const char *zName,
  sqlite3_file *pFile,
  int flags,
  int *pOutFlags
){
  int rc;
  TestvfsFile *p = (TestvfsFile *)pFile;
  p->pShm = 0;
  p->pShmId = 0;
  p->zFilename = zName;
  p->pVfs = pVfs;
  p->pReal = (sqlite3_file *)&p[1];
  rc = sqlite3OsOpen(PARENTVFS(pVfs), zName, p->pReal, flags, pOutFlags);
  if( p->pReal->pMethods ){
    sqlite3_io_methods *pMethods;
    pMethods = (sqlite3_io_methods *)ckalloc(sizeof(sqlite3_io_methods));
    memcpy(pMethods, &tvfs_io_methods, sizeof(sqlite3_io_methods));
    if( ((Testvfs *)pVfs->pAppData)->isNoshm ){
      pMethods->xShmOpen = 0;
      pMethods->xShmGet = 0;
      pMethods->xShmSize = 0;
      pMethods->xShmRelease = 0;
      pMethods->xShmClose = 0;
      pMethods->xShmLock = 0;
    }
    pFile->pMethods = pMethods;
  }

  return rc;
}

/*
** Delete the file located at zPath. If the dirSync argument is true,
** ensure the file-system modifications are synced to disk before
** returning.
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/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int tvfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
  return PARENTVFS(pVfs)->xCurrentTime(PARENTVFS(pVfs), pTimeOut);
}

static void tvfsGrowBuffer(TestvfsShm *pShm, int reqSize, int *pNewSize){
  TestvfsBuffer *pBuffer = pShm->pBuffer;
  if( reqSize>pBuffer->n ){
    pBuffer->a = (u8 *)ckrealloc((char *)pBuffer->a, reqSize);
    memset(&pBuffer->a[pBuffer->n], 0x55, reqSize-pBuffer->n);
    pBuffer->n = reqSize;
  }
  *pNewSize = pBuffer->n;
}







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/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int tvfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
  return PARENTVFS(pVfs)->xCurrentTime(PARENTVFS(pVfs), pTimeOut);
}

static void tvfsGrowBuffer(TestvfsFile *pFd, int reqSize, int *pNewSize){
  TestvfsBuffer *pBuffer = pFd->pShm;
  if( reqSize>pBuffer->n ){
    pBuffer->a = (u8 *)ckrealloc((char *)pBuffer->a, reqSize);
    memset(&pBuffer->a[pBuffer->n], 0x55, reqSize-pBuffer->n);
    pBuffer->n = reqSize;
  }
  *pNewSize = pBuffer->n;
}
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    }
  }

  return 0;
}

static int tvfsShmOpen(
  sqlite3_vfs *pVfs, 
  const char *zName, 
  sqlite3_shm **pp
){
  Testvfs *p = (Testvfs *)(pVfs->pAppData);
  int rc = SQLITE_OK;             /* Return code */
  Tcl_Obj *pId = 0;               /* Id for this connection */
  TestvfsBuffer *pBuffer;         /* Buffer to open connection to */
  TestvfsShm *pShm;               /* New shm handle */





  /* Evaluate the Tcl script: 
  **
  **   SCRIPT xShmOpen FILENAME
  **
  ** If the script returns an SQLite error code other than SQLITE_OK, an
  ** error is returned to the caller. If it returns SQLITE_OK, the new
  ** connection is named "anon". Otherwise, the value returned by the
  ** script is used as the connection name.
  */
  tvfsExecTcl(p, "xShmOpen", Tcl_NewStringObj(zName, -1), 0, 0);
  if( tvfsResultCode(p, &rc) ){
    if( rc!=SQLITE_OK ) return rc;
    pId = Tcl_NewStringObj("anon", -1);
  }else{
    pId = Tcl_GetObjResult(p->interp);
  }
  Tcl_IncrRefCount(pId);

  /* Allocate the TestvfsShm handle. */
  pShm = (TestvfsShm *)ckalloc(sizeof(TestvfsShm));
  memset(pShm, 0, sizeof(TestvfsShm));
  pShm->id = pId;

  /* Search for a TestvfsBuffer. Create a new one if required. */
  for(pBuffer=p->pBuffer; pBuffer; pBuffer=pBuffer->pNext){
    if( 0==strcmp(zName, pBuffer->zFile) ) break;
  }
  if( !pBuffer ){
    int nByte = sizeof(TestvfsBuffer) + strlen(zName) + 1;
    pBuffer = (TestvfsBuffer *)ckalloc(nByte);
    memset(pBuffer, 0, nByte);
    pBuffer->zFile = (char *)&pBuffer[1];
    strcpy(pBuffer->zFile, zName);
    pBuffer->pNext = p->pBuffer;
    p->pBuffer = pBuffer;
  }

  /* Connect the TestvfsBuffer to the new TestvfsShm handle and return. */
  pBuffer->nRef++;
  pShm->pBuffer = pBuffer;
  *pp = (sqlite3_shm *)pShm;
  return SQLITE_OK;
}

static int tvfsShmSize(
  sqlite3_vfs *pVfs,
  sqlite3_shm *pShmHandle,
  int reqSize,
  int *pNewSize
){
  int rc = SQLITE_OK;

  Testvfs *p = (Testvfs *)(pVfs->pAppData);
  TestvfsShm *pShm = (TestvfsShm *)pShmHandle;

  tvfsExecTcl(p, "xShmSize", 
      Tcl_NewStringObj(pShm->pBuffer->zFile, -1), pShm->id, 0
  );
  tvfsResultCode(p, &rc);
  if( rc==SQLITE_OK ){
    tvfsGrowBuffer(pShm, reqSize, pNewSize);
  }
  return rc;
}

static int tvfsShmGet(
  sqlite3_vfs *pVfs,
  sqlite3_shm *pShmHandle, 
  int reqMapSize, 
  int *pMapSize, 
  void **pp
){
  int rc = SQLITE_OK;

  Testvfs *p = (Testvfs *)(pVfs->pAppData);
  TestvfsShm *pShm = (TestvfsShm *)pShmHandle;

  tvfsExecTcl(p, "xShmGet", 
      Tcl_NewStringObj(pShm->pBuffer->zFile, -1), pShm->id, 0
  );
  tvfsResultCode(p, &rc);
  if( rc==SQLITE_OK ){
    tvfsGrowBuffer(pShm, reqMapSize, pMapSize);
    *pp = pShm->pBuffer->a;
  }
  return rc;
}

static int tvfsShmRelease(sqlite3_vfs *pVfs, sqlite3_shm *pShmHandle){
  int rc = SQLITE_OK;

  Testvfs *p = (Testvfs *)(pVfs->pAppData);
  TestvfsShm *pShm = (TestvfsShm *)pShmHandle;

  tvfsExecTcl(p, "xShmRelease", 
      Tcl_NewStringObj(pShm->pBuffer->zFile, -1), pShm->id, 0
  );
  tvfsResultCode(p, &rc);

  return rc;
}

static int tvfsShmLock(
  sqlite3_vfs *pVfs,
  sqlite3_shm *pShmHandle,
  int desiredLock,
  int *gotLock
){
  int rc = SQLITE_OK;

  Testvfs *p = (Testvfs *)(pVfs->pAppData);
  TestvfsShm *pShm = (TestvfsShm *)pShmHandle;
  char *zLock = "";

  switch( desiredLock ){
    case SQLITE_SHM_READ:         zLock = "READ";       break;
    case SQLITE_SHM_WRITE:        zLock = "WRITE";      break;
    case SQLITE_SHM_CHECKPOINT:   zLock = "CHECKPOINT"; break;
    case SQLITE_SHM_RECOVER:      zLock = "RECOVER";    break;
    case SQLITE_SHM_PENDING:      zLock = "PENDING";    break;
    case SQLITE_SHM_UNLOCK:       zLock = "UNLOCK";     break;
  }
  tvfsExecTcl(p, "xShmLock", 
      Tcl_NewStringObj(pShm->pBuffer->zFile, -1), pShm->id,
      Tcl_NewStringObj(zLock, -1)
  );
  tvfsResultCode(p, &rc);
  if( rc==SQLITE_OK ){
    *gotLock = desiredLock;
  }

  return rc;
}

static int tvfsShmClose(
  sqlite3_vfs *pVfs, 
  sqlite3_shm *pShmHandle, 
  int deleteFlag
){
  int rc = SQLITE_OK;

  Testvfs *p = (Testvfs *)(pVfs->pAppData);
  TestvfsShm *pShm = (TestvfsShm *)pShmHandle;
  TestvfsBuffer *pBuffer = pShm->pBuffer;


#if 0
  assert( (deleteFlag!=0)==(pBuffer->nRef==1) );
#endif

  tvfsExecTcl(p, "xShmClose", 
      Tcl_NewStringObj(pShm->pBuffer->zFile, -1), pShm->id, 0
  );
  tvfsResultCode(p, &rc);

  pBuffer->nRef--;
  if( pBuffer->nRef==0 ){
    TestvfsBuffer **pp;
    for(pp=&p->pBuffer; *pp!=pBuffer; pp=&((*pp)->pNext));
    *pp = (*pp)->pNext;
    ckfree((char *)pBuffer->a);
    ckfree((char *)pBuffer);
  }
  Tcl_DecrRefCount(pShm->id);

  ckfree((char *)pShm);

  return rc;
}

static int testvfs_obj_cmd(
  ClientData cd,
  Tcl_Interp *interp,







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544
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550
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597
598
599
600
601
602
603
604
605
606
607
608
    }
  }

  return 0;
}

static int tvfsShmOpen(


  sqlite3_file *pFileDes
){
  Testvfs *p;
  int rc = SQLITE_OK;             /* Return code */
  Tcl_Obj *pId = 0;               /* Id for this connection */
  TestvfsBuffer *pBuffer;         /* Buffer to open connection to */
  TestvfsFile *pFd;               /* The testvfs file structure */

  pFd = (TestvfsFile*)pFileDes;
  p = (Testvfs *)pFd->pVfs->pAppData;
  assert( pFd->pShmId==0 && pFd->pShm==0 );

  /* Evaluate the Tcl script: 
  **
  **   SCRIPT xShmOpen FILENAME
  **
  ** If the script returns an SQLite error code other than SQLITE_OK, an
  ** error is returned to the caller. If it returns SQLITE_OK, the new
  ** connection is named "anon". Otherwise, the value returned by the
  ** script is used as the connection name.
  */
  tvfsExecTcl(p, "xShmOpen", Tcl_NewStringObj(pFd->zFilename, -1), 0, 0);
  if( tvfsResultCode(p, &rc) ){
    if( rc!=SQLITE_OK ) return rc;
    pId = Tcl_NewStringObj("anon", -1);
  }else{
    pId = Tcl_GetObjResult(p->interp);
  }
  Tcl_IncrRefCount(pId);




  pFd->pShmId = pId;

  /* Search for a TestvfsBuffer. Create a new one if required. */
  for(pBuffer=p->pBuffer; pBuffer; pBuffer=pBuffer->pNext){
    if( 0==strcmp(pFd->zFilename, pBuffer->zFile) ) break;
  }
  if( !pBuffer ){
    int nByte = sizeof(TestvfsBuffer) + strlen(pFd->zFilename) + 1;
    pBuffer = (TestvfsBuffer *)ckalloc(nByte);
    memset(pBuffer, 0, nByte);
    pBuffer->zFile = (char *)&pBuffer[1];
    strcpy(pBuffer->zFile, pFd->zFilename);
    pBuffer->pNext = p->pBuffer;
    p->pBuffer = pBuffer;
  }

  /* Connect the TestvfsBuffer to the new TestvfsShm handle and return. */
  pBuffer->nRef++;
  pFd->pShm = pBuffer;

  return SQLITE_OK;
}

static int tvfsShmSize(
  sqlite3_file *pFile,

  int reqSize,
  int *pNewSize
){
  int rc = SQLITE_OK;
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);


  tvfsExecTcl(p, "xShmSize", 
      Tcl_NewStringObj(pFd->pShm->zFile, -1), pFd->pShmId, 0
  );
  tvfsResultCode(p, &rc);
  if( rc==SQLITE_OK ){
    tvfsGrowBuffer(pFd, reqSize, pNewSize);
  }
  return rc;
}

static int tvfsShmGet(
  sqlite3_file *pFile, 

  int reqMapSize, 
  int *pMapSize, 
  void **pp
){
  int rc = SQLITE_OK;
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);


  tvfsExecTcl(p, "xShmGet", 
      Tcl_NewStringObj(pFd->pShm->zFile, -1), pFd->pShmId, 0
  );
  tvfsResultCode(p, &rc);
  if( rc==SQLITE_OK ){
    tvfsGrowBuffer(pFd, reqMapSize, pMapSize);
    *pp = pFd->pShm->a;
  }
  return rc;
}

static int tvfsShmRelease(sqlite3_file *pFile){
  int rc = SQLITE_OK;
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);


  tvfsExecTcl(p, "xShmRelease", 
      Tcl_NewStringObj(pFd->pShm->zFile, -1), pFd->pShmId, 0
  );
  tvfsResultCode(p, &rc);

  return rc;
}

static int tvfsShmLock(
  sqlite3_file *pFile,

  int desiredLock,
  int *gotLock
){
  int rc = SQLITE_OK;
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);

  char *zLock = "";

  switch( desiredLock ){
    case SQLITE_SHM_READ:         zLock = "READ";       break;
    case SQLITE_SHM_WRITE:        zLock = "WRITE";      break;
    case SQLITE_SHM_CHECKPOINT:   zLock = "CHECKPOINT"; break;
    case SQLITE_SHM_RECOVER:      zLock = "RECOVER";    break;
    case SQLITE_SHM_PENDING:      zLock = "PENDING";    break;
    case SQLITE_SHM_UNLOCK:       zLock = "UNLOCK";     break;
  }
  tvfsExecTcl(p, "xShmLock", 
      Tcl_NewStringObj(pFd->pShm->zFile, -1), pFd->pShmId,
      Tcl_NewStringObj(zLock, -1)
  );
  tvfsResultCode(p, &rc);
  if( rc==SQLITE_OK ){
    *gotLock = desiredLock;
  }

  return rc;
}

static int tvfsShmClose(
  sqlite3_file *pFile,

  int deleteFlag
){
  int rc = SQLITE_OK;
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);

  TestvfsBuffer *pBuffer = pFd->pShm;

  assert( pFd->pShmId && pFd->pShm );
#if 0
  assert( (deleteFlag!=0)==(pBuffer->nRef==1) );
#endif

  tvfsExecTcl(p, "xShmClose", 
      Tcl_NewStringObj(pFd->pShm->zFile, -1), pFd->pShmId, 0
  );
  tvfsResultCode(p, &rc);

  pBuffer->nRef--;
  if( pBuffer->nRef==0 ){
    TestvfsBuffer **pp;
    for(pp=&p->pBuffer; *pp!=pBuffer; pp=&((*pp)->pNext));
    *pp = (*pp)->pNext;
    ckfree((char *)pBuffer->a);
    ckfree((char *)pBuffer);
  }
  Tcl_DecrRefCount(pFd->pShmId);
  pFd->pShmId = 0;
  pFd->pShm = 0;

  return rc;
}

static int testvfs_obj_cmd(
  ClientData cd,
  Tcl_Interp *interp,
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
*/
static int testvfs_cmd(
  ClientData cd,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){

  static sqlite3_vfs tvfs_vfs = {
    2,                            /* iVersion */
    sizeof(tvfs_file),            /* szOsFile */
    0,                            /* mxPathname */
    0,                            /* pNext */
    0,                            /* zName */
    0,                            /* pAppData */
    tvfsOpen,                     /* xOpen */
    tvfsDelete,                   /* xDelete */
    tvfsAccess,                   /* xAccess */







<


|







708
709
710
711
712
713
714

715
716
717
718
719
720
721
722
723
724
*/
static int testvfs_cmd(
  ClientData cd,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){

  static sqlite3_vfs tvfs_vfs = {
    2,                            /* iVersion */
    sizeof(TestvfsFile),            /* szOsFile */
    0,                            /* mxPathname */
    0,                            /* pNext */
    0,                            /* zName */
    0,                            /* pAppData */
    tvfsOpen,                     /* xOpen */
    tvfsDelete,                   /* xDelete */
    tvfsAccess,                   /* xAccess */
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
    0,                            /* xDlSym */
    0,                            /* xDlClose */
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
    tvfsRandomness,               /* xRandomness */
    tvfsSleep,                    /* xSleep */
    tvfsCurrentTime,              /* xCurrentTime */
    0,                            /* xGetLastError */
    tvfsShmOpen,
    tvfsShmSize,
    tvfsShmGet,
    tvfsShmRelease,
    tvfsShmLock,
    tvfsShmClose,
    0,
    0,
  };

  Testvfs *p;                     /* New object */
  sqlite3_vfs *pVfs;              /* New VFS */
  char *zVfs;







<
<
<
<
<
<







734
735
736
737
738
739
740






741
742
743
744
745
746
747
    0,                            /* xDlSym */
    0,                            /* xDlClose */
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
    tvfsRandomness,               /* xRandomness */
    tvfsSleep,                    /* xSleep */
    tvfsCurrentTime,              /* xCurrentTime */
    0,                            /* xGetLastError */






    0,
    0,
  };

  Testvfs *p;                     /* New object */
  sqlite3_vfs *pVfs;              /* New VFS */
  char *zVfs;
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
  pVfs = (sqlite3_vfs *)ckalloc(sizeof(sqlite3_vfs));
  memcpy(pVfs, &tvfs_vfs, sizeof(sqlite3_vfs));
  pVfs->pAppData = (void *)p;
  pVfs->zName = p->zName;
  pVfs->mxPathname = p->pParent->mxPathname;
  pVfs->szOsFile += p->pParent->szOsFile;
  p->pVfs = pVfs;
  if( isNoshm ){
    pVfs->xShmOpen = 0;
    pVfs->xShmGet = 0;
    pVfs->xShmSize = 0;
    pVfs->xShmRelease = 0;
    pVfs->xShmClose = 0;
    pVfs->xShmLock = 0;
  }

  Tcl_CreateObjCommand(interp, zVfs, testvfs_obj_cmd, p, testvfs_obj_del);
  sqlite3_vfs_register(pVfs, 0);

  return TCL_OK;

 bad_args:







|
<
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784
785
786
787
788
789
790
791







792
793
794
795
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797
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  pVfs = (sqlite3_vfs *)ckalloc(sizeof(sqlite3_vfs));
  memcpy(pVfs, &tvfs_vfs, sizeof(sqlite3_vfs));
  pVfs->pAppData = (void *)p;
  pVfs->zName = p->zName;
  pVfs->mxPathname = p->pParent->mxPathname;
  pVfs->szOsFile += p->pParent->szOsFile;
  p->pVfs = pVfs;
  p->isNoshm = isNoshm;








  Tcl_CreateObjCommand(interp, zVfs, testvfs_obj_cmd, p, testvfs_obj_del);
  sqlite3_vfs_register(pVfs, 0);

  return TCL_OK;

 bad_args:
Changes to src/vdbe.c.
985
986
987
988
989
990
991
992
993
994
995
996
997
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1001
1002
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  assert( pOp->p1 <= SQLITE_MAX_LENGTH );
  sqlite3VdbeMemSetStr(pOut, pOp->p4.z, pOp->p1, 0, 0);
  pOut->enc = encoding;
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: Variable P1 P2 P3 P4 *
**
** Transfer the values of bound parameters P1..P1+P3-1 into registers
** P2..P2+P3-1.
**
** If the parameter is named, then its name appears in P4 and P3==1.
** The P4 value is used by sqlite3_bind_parameter_name().
*/
case OP_Variable: {
  int p1;          /* Variable to copy from */
  int p2;          /* Register to copy to */
  int n;           /* Number of values left to copy */
  Mem *pVar;       /* Value being transferred */

  p1 = pOp->p1 - 1;
  p2 = pOp->p2;
  n = pOp->p3;
  assert( p1>=0 && p1+n<=p->nVar );
  assert( p2>=1 && p2+n-1<=p->nMem );
  assert( pOp->p4.z==0 || pOp->p3==1 || pOp->p3==0 );

  while( n-- > 0 ){
    pVar = &p->aVar[p1++];
    if( sqlite3VdbeMemTooBig(pVar) ){
      goto too_big;
    }
    pOut = &aMem[p2++];
    sqlite3VdbeMemReleaseExternal(pOut);
    pOut->flags = MEM_Null;
    sqlite3VdbeMemShallowCopy(pOut, pVar, MEM_Static);
    UPDATE_MAX_BLOBSIZE(pOut);
  }
  break;
}

/* Opcode: Move P1 P2 P3 * *
**
** Move the values in register P1..P1+P3-1 over into
** registers P2..P2+P3-1.  Registers P1..P1+P1-1 are







|

|
<




|
<
<
<


<
<
<
|
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<
|
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|
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<







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989
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995
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1002




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1006



1007
1008

1009
1010
1011
1012
1013
1014
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  assert( pOp->p1 <= SQLITE_MAX_LENGTH );
  sqlite3VdbeMemSetStr(pOut, pOp->p4.z, pOp->p1, 0, 0);
  pOut->enc = encoding;
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: Variable P1 P2 * P4 *
**
** Transfer the values of bound parameter P1 into register P2

**
** If the parameter is named, then its name appears in P4 and P3==1.
** The P4 value is used by sqlite3_bind_parameter_name().
*/
case OP_Variable: {            /* out2-prerelease */



  Mem *pVar;       /* Value being transferred */




  assert( pOp->p1>0 && pOp->p1<=p->nVar );




  pVar = &p->aVar[pOp->p1 - 1];
  if( sqlite3VdbeMemTooBig(pVar) ){
    goto too_big;
  }



  sqlite3VdbeMemShallowCopy(pOut, pVar, MEM_Static);
  UPDATE_MAX_BLOBSIZE(pOut);

  break;
}

/* Opcode: Move P1 P2 P3 * *
**
** Move the values in register P1..P1+P3-1 over into
** registers P2..P2+P3-1.  Registers P1..P1+P1-1 are
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
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5271
5272
5273
5274
  zFilename = sqlite3PagerFilename(pPager);
  pVfs = sqlite3PagerVfs(pPager);

  /* Do not allow a transition to journal_mode=WAL for a database
  ** in temporary storage or if the VFS does not support xShmOpen.
  */
  if( eNew==PAGER_JOURNALMODE_WAL
   && (zFilename[0]==0                               /* Temp file */
         || pVfs->iVersion<2 || pVfs->xShmOpen==0)   /* No xShmOpen support */
  ){
    eNew = PAGER_JOURNALMODE_QUERY;
  }

  if( eNew!=PAGER_JOURNALMODE_QUERY ){
    eOld = sqlite3PagerJournalMode(pPager, PAGER_JOURNALMODE_QUERY);
    if( (eNew!=eOld)







|
|







5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
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5256
5257
5258
5259
  zFilename = sqlite3PagerFilename(pPager);
  pVfs = sqlite3PagerVfs(pPager);

  /* Do not allow a transition to journal_mode=WAL for a database
  ** in temporary storage or if the VFS does not support xShmOpen.
  */
  if( eNew==PAGER_JOURNALMODE_WAL
   && (zFilename[0]==0                         /* Temp file */
       || !sqlite3PagerWalSupported(pPager))   /* No xShmOpen support */
  ){
    eNew = PAGER_JOURNALMODE_QUERY;
  }

  if( eNew!=PAGER_JOURNALMODE_QUERY ){
    eOld = sqlite3PagerJournalMode(pPager, PAGER_JOURNALMODE_QUERY);
    if( (eNew!=eOld)
5305
5306
5307
5308
5309
5310
5311

5312
5313
5314
5315
5316
5317
5318
        */
        assert( sqlite3BtreeIsInTrans(pBt)==0 );
        if( rc==SQLITE_OK ){
          rc = sqlite3BtreeSetVersion(pBt, 
                                      (eNew==PAGER_JOURNALMODE_WAL ? 2 : 1));
          if( rc==SQLITE_BUSY && pOp->p5==0 ) goto abort_due_to_error;
        }else if( rc==SQLITE_BUSY ){

          rc = SQLITE_OK;
        }
      }
    }
  }
#endif /* ifndef SQLITE_OMIT_WAL */








>







5290
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5292
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5296
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5299
5300
5301
5302
5303
5304
        */
        assert( sqlite3BtreeIsInTrans(pBt)==0 );
        if( rc==SQLITE_OK ){
          rc = sqlite3BtreeSetVersion(pBt, 
                                      (eNew==PAGER_JOURNALMODE_WAL ? 2 : 1));
          if( rc==SQLITE_BUSY && pOp->p5==0 ) goto abort_due_to_error;
        }else if( rc==SQLITE_BUSY ){
          eNew = PAGER_JOURNALMODE_QUERY;
          rc = SQLITE_OK;
        }
      }
    }
  }
#endif /* ifndef SQLITE_OMIT_WAL */

Changes to src/wal.c.
121
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125
126
127

128
129
130
131
132
133
134


135
136
137
138
139
140
141
142
143

/*
** An open write-ahead log file is represented by an instance of the
** following object.
*/
struct Wal {
  sqlite3_vfs *pVfs;         /* The VFS used to create pFd */

  sqlite3_file *pFd;         /* File handle for WAL file */
  u32 iCallback;             /* Value to pass to log callback (or 0) */
  sqlite3_shm *pWIndex;      /* The open wal-index file */
  int szWIndex;              /* Size of the wal-index that is mapped in mem */
  u32 *pWiData;              /* Pointer to wal-index content in memory */
  u8 lockState;              /* SQLITE_SHM_xxxx constant showing lock state */
  u8 readerType;             /* SQLITE_SHM_READ or SQLITE_SHM_READ_FULL */


  WalIndexHdr hdr;           /* Wal-index for current snapshot */
  char *zName;               /* Name of underlying storage */
};


/*
** This structure is used to implement an iterator that iterates through
** all frames in the log in database page order. Where two or more frames
** correspond to the same database page, the iterator visits only the 







>
|

<




>
>

|







121
122
123
124
125
126
127
128
129
130

131
132
133
134
135
136
137
138
139
140
141
142
143
144
145

/*
** An open write-ahead log file is represented by an instance of the
** following object.
*/
struct Wal {
  sqlite3_vfs *pVfs;         /* The VFS used to create pFd */
  sqlite3_file *pDbFd;       /* File handle for the database file */
  sqlite3_file *pWalFd;      /* File handle for WAL file */
  u32 iCallback;             /* Value to pass to log callback (or 0) */

  int szWIndex;              /* Size of the wal-index that is mapped in mem */
  u32 *pWiData;              /* Pointer to wal-index content in memory */
  u8 lockState;              /* SQLITE_SHM_xxxx constant showing lock state */
  u8 readerType;             /* SQLITE_SHM_READ or SQLITE_SHM_READ_FULL */
  u8 exclusiveMode;          /* Non-zero if connection is in exclusive mode */
  u8 isWindexOpen;           /* True if ShmOpen() called on pDbFd */
  WalIndexHdr hdr;           /* Wal-index for current snapshot */
  char *zWalName;            /* Name of WAL file */
};


/*
** This structure is used to implement an iterator that iterates through
** all frames in the log in database page order. Where two or more frames
** correspond to the same database page, the iterator visits only the 
213
214
215
216
217
218
219
220
221


222
223
224
225
226
227

228
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230
231
232
233
234
** Attempt to change the lock status.
**
** When changing the lock status to SQLITE_SHM_READ, store the
** type of reader lock (either SQLITE_SHM_READ or SQLITE_SHM_READ_FULL)
** in pWal->readerType.
*/
static int walSetLock(Wal *pWal, int desiredStatus){
  int rc, got;
  if( pWal->lockState==desiredStatus ) return SQLITE_OK;


  got = pWal->lockState;
  rc = pWal->pVfs->xShmLock(pWal->pVfs, pWal->pWIndex, desiredStatus, &got);
  pWal->lockState = got;
  if( got==SQLITE_SHM_READ_FULL || got==SQLITE_SHM_READ ){
    pWal->readerType = got;
    pWal->lockState = SQLITE_SHM_READ;

  }
  return rc;
}

/*
** Update the header of the wal-index file.
*/







|
|
>
>
|
|
|
|
|
|
>







215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
** Attempt to change the lock status.
**
** When changing the lock status to SQLITE_SHM_READ, store the
** type of reader lock (either SQLITE_SHM_READ or SQLITE_SHM_READ_FULL)
** in pWal->readerType.
*/
static int walSetLock(Wal *pWal, int desiredStatus){
  int rc = SQLITE_OK;             /* Return code */
  if( pWal->exclusiveMode || pWal->lockState==desiredStatus ){
    pWal->lockState = desiredStatus;
  }else{
    int got = pWal->lockState;
    rc = sqlite3OsShmLock(pWal->pDbFd, desiredStatus, &got);
    pWal->lockState = got;
    if( got==SQLITE_SHM_READ_FULL || got==SQLITE_SHM_READ ){
      pWal->readerType = got;
      pWal->lockState = SQLITE_SHM_READ;
    }
  }
  return rc;
}

/*
** Update the header of the wal-index file.
*/
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416

417
418
419
420
421
422
423
424
425

/*
** Release our reference to the wal-index memory map, if we are holding
** it.
*/
static void walIndexUnmap(Wal *pWal){
  if( pWal->pWiData ){
    pWal->pVfs->xShmRelease(pWal->pVfs, pWal->pWIndex);
    pWal->pWiData = 0;
  }
}

/*
** Map the wal-index file into memory if it isn't already. 
**
** The reqSize parameter is the minimum required size of the mapping.
** A value of -1 means "don't care".
*/
static int walIndexMap(Wal *pWal, int reqSize){
  int rc = SQLITE_OK;
  if( pWal->pWiData==0 || reqSize>pWal->szWIndex ){

    rc = pWal->pVfs->xShmGet(pWal->pVfs, pWal->pWIndex, reqSize,
                             &pWal->szWIndex, (void**)(char*)&pWal->pWiData);
    if( rc==SQLITE_OK && pWal->pWiData==0 ){
      /* Make sure pWal->pWiData is not NULL while we are holding the
      ** lock on the mapping. */
      assert( pWal->szWIndex==0 );
      pWal->pWiData = &pWal->iCallback;
    }
    if( rc!=SQLITE_OK ){







|













>
|
|







401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431

/*
** Release our reference to the wal-index memory map, if we are holding
** it.
*/
static void walIndexUnmap(Wal *pWal){
  if( pWal->pWiData ){
    sqlite3OsShmRelease(pWal->pDbFd);
    pWal->pWiData = 0;
  }
}

/*
** Map the wal-index file into memory if it isn't already. 
**
** The reqSize parameter is the minimum required size of the mapping.
** A value of -1 means "don't care".
*/
static int walIndexMap(Wal *pWal, int reqSize){
  int rc = SQLITE_OK;
  if( pWal->pWiData==0 || reqSize>pWal->szWIndex ){
    walIndexUnmap(pWal);
    rc = sqlite3OsShmGet(pWal->pDbFd, reqSize, &pWal->szWIndex,
                             (void**)(char*)&pWal->pWiData);
    if( rc==SQLITE_OK && pWal->pWiData==0 ){
      /* Make sure pWal->pWiData is not NULL while we are holding the
      ** lock on the mapping. */
      assert( pWal->szWIndex==0 );
      pWal->pWiData = &pWal->iCallback;
    }
    if( rc!=SQLITE_OK ){
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
**
** If enlargeTo is non-negative, then increase the size of the underlying
** storage to be at least as big as enlargeTo before remapping.
*/
static int walIndexRemap(Wal *pWal, int enlargeTo){
  int rc;
  int sz;
  rc = pWal->pVfs->xShmSize(pWal->pVfs, pWal->pWIndex, enlargeTo, &sz);
  if( rc==SQLITE_OK && sz>pWal->szWIndex ){
    walIndexUnmap(pWal);
    rc = walIndexMap(pWal, sz);
  }
  return rc;
}








|







441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
**
** If enlargeTo is non-negative, then increase the size of the underlying
** storage to be at least as big as enlargeTo before remapping.
*/
static int walIndexRemap(Wal *pWal, int enlargeTo){
  int rc;
  int sz;
  rc = sqlite3OsShmSize(pWal->pDbFd, enlargeTo, &sz);
  if( rc==SQLITE_OK && sz>pWal->szWIndex ){
    walIndexUnmap(pWal);
    rc = walIndexMap(pWal, sz);
  }
  return rc;
}

553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
  int rc;                         /* Return Code */
  i64 nSize;                      /* Size of log file */
  WalIndexHdr hdr;              /* Recovered wal-index header */

  assert( pWal->lockState>SQLITE_SHM_READ );
  memset(&hdr, 0, sizeof(hdr));

  rc = sqlite3OsFileSize(pWal->pFd, &nSize);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  if( nSize>WAL_FRAME_HDRSIZE ){
    u8 aBuf[WAL_FRAME_HDRSIZE];   /* Buffer to load first frame header into */
    u8 *aFrame = 0;               /* Malloc'd buffer to load entire frame */
    int nFrame;                   /* Number of bytes at aFrame */
    u8 *aData;                    /* Pointer to data part of aFrame buffer */
    int iFrame;                   /* Index of last frame read */
    i64 iOffset;                  /* Next offset to read from log file */
    int nPgsz;                    /* Page size according to the log */
    u32 aCksum[2];                /* Running checksum */

    /* Read in the first frame header in the file (to determine the 
    ** database page size).
    */
    rc = sqlite3OsRead(pWal->pFd, aBuf, WAL_HDRSIZE, 0);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    /* If the database page size is not a power of two, or is greater than
    ** SQLITE_MAX_PAGE_SIZE, conclude that the log file contains no valid data.
    */







|

















|







559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
  int rc;                         /* Return Code */
  i64 nSize;                      /* Size of log file */
  WalIndexHdr hdr;              /* Recovered wal-index header */

  assert( pWal->lockState>SQLITE_SHM_READ );
  memset(&hdr, 0, sizeof(hdr));

  rc = sqlite3OsFileSize(pWal->pWalFd, &nSize);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  if( nSize>WAL_FRAME_HDRSIZE ){
    u8 aBuf[WAL_FRAME_HDRSIZE];   /* Buffer to load first frame header into */
    u8 *aFrame = 0;               /* Malloc'd buffer to load entire frame */
    int nFrame;                   /* Number of bytes at aFrame */
    u8 *aData;                    /* Pointer to data part of aFrame buffer */
    int iFrame;                   /* Index of last frame read */
    i64 iOffset;                  /* Next offset to read from log file */
    int nPgsz;                    /* Page size according to the log */
    u32 aCksum[2];                /* Running checksum */

    /* Read in the first frame header in the file (to determine the 
    ** database page size).
    */
    rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    /* If the database page size is not a power of two, or is greater than
    ** SQLITE_MAX_PAGE_SIZE, conclude that the log file contains no valid data.
    */
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
    iFrame = 0;
    for(iOffset=WAL_HDRSIZE; (iOffset+nFrame)<=nSize; iOffset+=nFrame){
      u32 pgno;                   /* Database page number for frame */
      u32 nTruncate;              /* dbsize field from frame header */
      int isValid;                /* True if this frame is valid */

      /* Read and decode the next log frame. */
      rc = sqlite3OsRead(pWal->pFd, aFrame, nFrame, iOffset);
      if( rc!=SQLITE_OK ) break;
      isValid = walDecodeFrame(aCksum, &pgno, &nTruncate, nPgsz, aData, aFrame);
      if( !isValid ) break;
      rc = walIndexAppend(pWal, ++iFrame, pgno);
      if( rc!=SQLITE_OK ) break;

      /* If nTruncate is non-zero, this is a commit record. */







|







608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
    iFrame = 0;
    for(iOffset=WAL_HDRSIZE; (iOffset+nFrame)<=nSize; iOffset+=nFrame){
      u32 pgno;                   /* Database page number for frame */
      u32 nTruncate;              /* dbsize field from frame header */
      int isValid;                /* True if this frame is valid */

      /* Read and decode the next log frame. */
      rc = sqlite3OsRead(pWal->pWalFd, aFrame, nFrame, iOffset);
      if( rc!=SQLITE_OK ) break;
      isValid = walDecodeFrame(aCksum, &pgno, &nTruncate, nPgsz, aData, aFrame);
      if( !isValid ) break;
      rc = walIndexAppend(pWal, ++iFrame, pgno);
      if( rc!=SQLITE_OK ) break;

      /* If nTruncate is non-zero, this is a commit record. */
640
641
642
643
644
645
646
647
648
649
650
651
652

653
654
655
656
657
658
659
  return rc;
}

/*
** Close an open wal-index.
*/
static void walIndexClose(Wal *pWal, int isDelete){
  sqlite3_shm *pWIndex = pWal->pWIndex;
  if( pWIndex ){
    sqlite3_vfs *pVfs = pWal->pVfs;
    int notUsed;
    pVfs->xShmLock(pVfs, pWIndex, SQLITE_SHM_UNLOCK, &notUsed);
    pVfs->xShmClose(pVfs, pWIndex, isDelete);

  }
}

/* 
** Open a connection to the log file associated with database zDb. The
** database file does not actually have to exist. zDb is used only to
** figure out the name of the log file to open. If the log file does not 







<
|
<

|
|
>







646
647
648
649
650
651
652

653

654
655
656
657
658
659
660
661
662
663
664
  return rc;
}

/*
** Close an open wal-index.
*/
static void walIndexClose(Wal *pWal, int isDelete){

  if( pWal->isWindexOpen ){

    int notUsed;
    sqlite3OsShmLock(pWal->pDbFd, SQLITE_SHM_UNLOCK, &notUsed);
    sqlite3OsShmClose(pWal->pDbFd, isDelete);
    pWal->isWindexOpen = 0;
  }
}

/* 
** Open a connection to the log file associated with database zDb. The
** database file does not actually have to exist. zDb is used only to
** figure out the name of the log file to open. If the log file does not 
667
668
669
670
671
672
673
674

675
676
677
678
679
680
681
682

683
684
685
686
687
688
689
690
691
692
693
694
695

696
697
698
699
700
701

702
703
704
705
706
707
708
709
710
711
712
713
714
715
**
** If the log file is successfully opened, SQLITE_OK is returned and 
** *ppWal is set to point to a new WAL handle. If an error occurs,
** an SQLite error code is returned and *ppWal is left unmodified.
*/
int sqlite3WalOpen(
  sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
  const char *zDb,                /* Name of database file */

  Wal **ppWal                     /* OUT: Allocated Wal handle */
){
  int rc;                         /* Return Code */
  Wal *pRet;                      /* Object to allocate and return */
  int flags;                      /* Flags passed to OsOpen() */
  char *zWal;                     /* Path to WAL file */
  int nWal;                       /* Length of zWal in bytes */


  assert( zDb );
  if( pVfs->xShmOpen==0 ) return SQLITE_CANTOPEN_BKPT;

  /* Allocate an instance of struct Wal to return. */
  *ppWal = 0;
  nWal = strlen(zDb);
  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile + nWal+5);
  if( !pRet ){
    return SQLITE_NOMEM;
  }

  pRet->pVfs = pVfs;
  pRet->pFd = (sqlite3_file *)&pRet[1];

  pRet->zName = zWal = pVfs->szOsFile + (char*)pRet->pFd;
  sqlite3_snprintf(nWal+5, zWal, "%s-wal", zDb);
  rc = pVfs->xShmOpen(pVfs, zDb, &pRet->pWIndex);

  /* Open file handle on the write-ahead log file. */
  if( rc==SQLITE_OK ){

    flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MAIN_JOURNAL);
    rc = sqlite3OsOpen(pVfs, zWal, pRet->pFd, flags, &flags);
  }

  if( rc!=SQLITE_OK ){
    walIndexClose(pRet, 0);
    sqlite3OsClose(pRet->pFd);
    sqlite3_free(pRet);
  }else{
    *ppWal = pRet;
  }
  return rc;
}








|
>





|


>
|
<



|
|





|
>
|
|
|



>

|




|







672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690

691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
**
** If the log file is successfully opened, SQLITE_OK is returned and 
** *ppWal is set to point to a new WAL handle. If an error occurs,
** an SQLite error code is returned and *ppWal is left unmodified.
*/
int sqlite3WalOpen(
  sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
  sqlite3_file *pDbFd,            /* The open database file */
  const char *zDbName,            /* Name of the database file */
  Wal **ppWal                     /* OUT: Allocated Wal handle */
){
  int rc;                         /* Return Code */
  Wal *pRet;                      /* Object to allocate and return */
  int flags;                      /* Flags passed to OsOpen() */
  char *zWal;                     /* Name of write-ahead log file */
  int nWal;                       /* Length of zWal in bytes */

  assert( zDbName && zDbName[0] );
  assert( pDbFd );


  /* Allocate an instance of struct Wal to return. */
  *ppWal = 0;
  nWal = sqlite3Strlen30(zDbName) + 5;
  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile + nWal);
  if( !pRet ){
    return SQLITE_NOMEM;
  }

  pRet->pVfs = pVfs;
  pRet->pWalFd = (sqlite3_file *)&pRet[1];
  pRet->pDbFd = pDbFd;
  pRet->zWalName = zWal = pVfs->szOsFile + (char*)pRet->pWalFd;
  sqlite3_snprintf(nWal, zWal, "%s-wal", zDbName);
  rc = sqlite3OsShmOpen(pDbFd);

  /* Open file handle on the write-ahead log file. */
  if( rc==SQLITE_OK ){
    pRet->isWindexOpen = 1;
    flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MAIN_JOURNAL);
    rc = sqlite3OsOpen(pVfs, zWal, pRet->pWalFd, flags, &flags);
  }

  if( rc!=SQLITE_OK ){
    walIndexClose(pRet, 0);
    sqlite3OsClose(pRet->pWalFd);
    sqlite3_free(pRet);
  }else{
    *ppWal = pRet;
  }
  return rc;
}

801
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803
804
805
806
807
808
809
810
811
812
813
814
815
}

/*
** Checkpoint the contents of the log file.
*/
static int walCheckpoint(
  Wal *pWal,                      /* Wal connection */
  sqlite3_file *pFd,              /* File descriptor open on db file */
  int sync_flags,                 /* Flags for OsSync() (or 0) */
  int nBuf,                       /* Size of zBuf in bytes */
  u8 *zBuf                        /* Temporary buffer to use */
){
  int rc;                         /* Return code */
  int pgsz = pWal->hdr.pgsz;      /* Database page-size */
  WalIterator *pIter = 0;         /* Wal iterator context */







<







809
810
811
812
813
814
815

816
817
818
819
820
821
822
}

/*
** Checkpoint the contents of the log file.
*/
static int walCheckpoint(
  Wal *pWal,                      /* Wal connection */

  int sync_flags,                 /* Flags for OsSync() (or 0) */
  int nBuf,                       /* Size of zBuf in bytes */
  u8 *zBuf                        /* Temporary buffer to use */
){
  int rc;                         /* Return code */
  int pgsz = pWal->hdr.pgsz;      /* Database page-size */
  WalIterator *pIter = 0;         /* Wal iterator context */
825
826
827
828
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855
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857
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859
  if( pWal->hdr.pgsz!=nBuf ){
    rc = SQLITE_CORRUPT_BKPT;
    goto out;
  }

  /* Sync the log file to disk */
  if( sync_flags ){
    rc = sqlite3OsSync(pWal->pFd, sync_flags);
    if( rc!=SQLITE_OK ) goto out;
  }

  /* Iterate through the contents of the log, copying data to the db file. */
  while( 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
    rc = sqlite3OsRead(pWal->pFd, zBuf, pgsz, 
        walFrameOffset(iFrame, pgsz) + WAL_FRAME_HDRSIZE
    );
    if( rc!=SQLITE_OK ) goto out;
    rc = sqlite3OsWrite(pFd, zBuf, pgsz, (iDbpage-1)*pgsz);
    if( rc!=SQLITE_OK ) goto out;
  }

  /* Truncate the database file */
  rc = sqlite3OsTruncate(pFd, ((i64)pWal->hdr.nPage*(i64)pgsz));
  if( rc!=SQLITE_OK ) goto out;

  /* Sync the database file. If successful, update the wal-index. */
  if( sync_flags ){
    rc = sqlite3OsSync(pFd, sync_flags);
    if( rc!=SQLITE_OK ) goto out;
  }
  pWal->hdr.iLastPg = 0;
  pWal->hdr.iCheck1 = 2;
  pWal->hdr.iCheck2 = 3;
  walIndexWriteHdr(pWal, &pWal->hdr);








|





|



|




|




|







832
833
834
835
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857
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859
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863
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865
866
  if( pWal->hdr.pgsz!=nBuf ){
    rc = SQLITE_CORRUPT_BKPT;
    goto out;
  }

  /* Sync the log file to disk */
  if( sync_flags ){
    rc = sqlite3OsSync(pWal->pWalFd, sync_flags);
    if( rc!=SQLITE_OK ) goto out;
  }

  /* Iterate through the contents of the log, copying data to the db file. */
  while( 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
    rc = sqlite3OsRead(pWal->pWalFd, zBuf, pgsz, 
        walFrameOffset(iFrame, pgsz) + WAL_FRAME_HDRSIZE
    );
    if( rc!=SQLITE_OK ) goto out;
    rc = sqlite3OsWrite(pWal->pDbFd, zBuf, pgsz, (iDbpage-1)*pgsz);
    if( rc!=SQLITE_OK ) goto out;
  }

  /* Truncate the database file */
  rc = sqlite3OsTruncate(pWal->pDbFd, ((i64)pWal->hdr.nPage*(i64)pgsz));
  if( rc!=SQLITE_OK ) goto out;

  /* Sync the database file. If successful, update the wal-index. */
  if( sync_flags ){
    rc = sqlite3OsSync(pWal->pDbFd, sync_flags);
    if( rc!=SQLITE_OK ) goto out;
  }
  pWal->hdr.iLastPg = 0;
  pWal->hdr.iCheck1 = 2;
  pWal->hdr.iCheck2 = 3;
  walIndexWriteHdr(pWal, &pWal->hdr);

868
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926
  **
  ** The easiest thing to do would be to write and sync a dummy header
  ** into the log at this point. Unfortunately, that turns out to be
  ** an unwelcome performance hit. Alternatives are...
  */
#if 0 
  memset(zBuf, 0, WAL_FRAME_HDRSIZE);
  rc = sqlite3OsWrite(pWal->pFd, zBuf, WAL_FRAME_HDRSIZE, 0);
  if( rc!=SQLITE_OK ) goto out;
  rc = sqlite3OsSync(pWal->pFd, pWal->sync_flags);
#endif

 out:
  walIteratorFree(pIter);
  return rc;
}

/*
** Close a connection to a log file.
*/
int sqlite3WalClose(
  Wal *pWal,                      /* Wal to close */
  sqlite3_file *pFd,              /* Database file */
  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */
  int nBuf,
  u8 *zBuf                        /* Buffer of at least nBuf bytes */
){
  int rc = SQLITE_OK;
  if( pWal ){
    int isDelete = 0;             /* True to unlink wal and wal-index files */

    /* If an EXCLUSIVE lock can be obtained on the database file (using the
    ** ordinary, rollback-mode locking methods, this guarantees that the
    ** connection associated with this log file is the only connection to
    ** the database. In this case checkpoint the database and unlink both
    ** the wal and wal-index files.
    **
    ** The EXCLUSIVE lock is not released before returning.
    */
    rc = sqlite3OsLock(pFd, SQLITE_LOCK_EXCLUSIVE);
    if( rc==SQLITE_OK ){
      rc = sqlite3WalCheckpoint(pWal, pFd, sync_flags, nBuf, zBuf, 0, 0);
      if( rc==SQLITE_OK ){
        isDelete = 1;
      }
      walIndexUnmap(pWal);
    }

    walIndexClose(pWal, isDelete);
    sqlite3OsClose(pWal->pFd);
    if( isDelete ){
      sqlite3OsDelete(pWal->pVfs, pWal->zName, 0);
    }
    sqlite3_free(pWal);
  }
  return rc;
}

/*







|

|












<
















|

|







|

|







875
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893
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895
896

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931
932
  **
  ** The easiest thing to do would be to write and sync a dummy header
  ** into the log at this point. Unfortunately, that turns out to be
  ** an unwelcome performance hit. Alternatives are...
  */
#if 0 
  memset(zBuf, 0, WAL_FRAME_HDRSIZE);
  rc = sqlite3OsWrite(pWal->pWalFd, zBuf, WAL_FRAME_HDRSIZE, 0);
  if( rc!=SQLITE_OK ) goto out;
  rc = sqlite3OsSync(pWal->pWalFd, pWal->sync_flags);
#endif

 out:
  walIteratorFree(pIter);
  return rc;
}

/*
** Close a connection to a log file.
*/
int sqlite3WalClose(
  Wal *pWal,                      /* Wal to close */

  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */
  int nBuf,
  u8 *zBuf                        /* Buffer of at least nBuf bytes */
){
  int rc = SQLITE_OK;
  if( pWal ){
    int isDelete = 0;             /* True to unlink wal and wal-index files */

    /* If an EXCLUSIVE lock can be obtained on the database file (using the
    ** ordinary, rollback-mode locking methods, this guarantees that the
    ** connection associated with this log file is the only connection to
    ** the database. In this case checkpoint the database and unlink both
    ** the wal and wal-index files.
    **
    ** The EXCLUSIVE lock is not released before returning.
    */
    rc = sqlite3OsLock(pWal->pDbFd, SQLITE_LOCK_EXCLUSIVE);
    if( rc==SQLITE_OK ){
      rc = sqlite3WalCheckpoint(pWal, sync_flags, nBuf, zBuf, 0, 0);
      if( rc==SQLITE_OK ){
        isDelete = 1;
      }
      walIndexUnmap(pWal);
    }

    walIndexClose(pWal, isDelete);
    sqlite3OsClose(pWal->pWalFd);
    if( isDelete ){
      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
    }
    sqlite3_free(pWal);
  }
  return rc;
}

/*
1183
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1190
1191
1192
1193
1194
1195
1196
1197
  /* If iRead is non-zero, then it is the log frame number that contains the
  ** required page. Read and return data from the log file.
  */
  walIndexUnmap(pWal);
  if( iRead ){
    i64 iOffset = walFrameOffset(iRead, pWal->hdr.pgsz) + WAL_FRAME_HDRSIZE;
    *pInWal = 1;
    return sqlite3OsRead(pWal->pFd, pOut, nOut, iOffset);
  }

  *pInWal = 0;
  return SQLITE_OK;
}









|







1189
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1203
  /* If iRead is non-zero, then it is the log frame number that contains the
  ** required page. Read and return data from the log file.
  */
  walIndexUnmap(pWal);
  if( iRead ){
    i64 iOffset = walFrameOffset(iRead, pWal->hdr.pgsz) + WAL_FRAME_HDRSIZE;
    *pInWal = 1;
    return sqlite3OsRead(pWal->pWalFd, pOut, nOut, iOffset);
  }

  *pInWal = 0;
  return SQLITE_OK;
}


1208
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1252


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1262
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1264

1265
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1270
1271
** This function returns SQLITE_OK if the caller may write to the database.
** Otherwise, if the caller is operating on a snapshot that has already
** been overwritten by another writer, SQLITE_BUSY is returned.
*/
int sqlite3WalWriteLock(Wal *pWal, int op){
  int rc = SQLITE_OK;
  if( op ){
    assert( pWal->lockState == SQLITE_SHM_READ );
    rc = walSetLock(pWal, SQLITE_SHM_WRITE);

    /* If this connection is not reading the most recent database snapshot,
    ** it is not possible to write to the database. In this case release
    ** the write locks and return SQLITE_BUSY.
    */
    if( rc==SQLITE_OK ){
      rc = walIndexMap(pWal, sizeof(WalIndexHdr));
      if( rc==SQLITE_OK
       && memcmp(&pWal->hdr, pWal->pWiData, sizeof(WalIndexHdr))
      ){
        rc = SQLITE_BUSY;
      }
      walIndexUnmap(pWal);
      if( rc!=SQLITE_OK ){
        walSetLock(pWal, SQLITE_SHM_READ);
      }
    }
  }else if( ALWAYS( pWal->lockState==SQLITE_SHM_WRITE ) ){
    rc = walSetLock(pWal, SQLITE_SHM_READ);
  }
  return rc;
}

/*
** If any data has been written (but not committed) to the log file, this
** function moves the write-pointer back to the start of the transaction.
**
** Additionally, the callback function is invoked for each frame written
** to the log since the start of the transaction. If the callback returns
** other than SQLITE_OK, it is not invoked again and the error code is
** returned to the caller.
**
** Otherwise, if the callback function does not return an error, this
** function returns SQLITE_OK.
*/
int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){


  int unused;
  int rc;
  Pgno iMax = pWal->hdr.iLastPg;
  Pgno iFrame;

  assert( pWal->pWiData==0 );
  rc = walIndexReadHdr(pWal, &unused);
  for(iFrame=pWal->hdr.iLastPg+1; rc==SQLITE_OK && iFrame<=iMax; iFrame++){
    assert( pWal->lockState==SQLITE_SHM_WRITE );
    rc = xUndo(pUndoCtx, pWal->pWiData[walIndexEntry(iFrame)]);
  }
  walIndexUnmap(pWal);

  return rc;
}

/* Return an integer that records the current (uncommitted) write
** position in the WAL
*/
u32 sqlite3WalSavepoint(Wal *pWal){







|


















|


















>
>
|
<
|
|
|
|
|
|
|
|
|
|
>







1214
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1261

1262
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1267
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1270
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1273
1274
1275
1276
1277
1278
1279
** This function returns SQLITE_OK if the caller may write to the database.
** Otherwise, if the caller is operating on a snapshot that has already
** been overwritten by another writer, SQLITE_BUSY is returned.
*/
int sqlite3WalWriteLock(Wal *pWal, int op){
  int rc = SQLITE_OK;
  if( op ){
    assert( pWal->lockState==SQLITE_SHM_READ );
    rc = walSetLock(pWal, SQLITE_SHM_WRITE);

    /* If this connection is not reading the most recent database snapshot,
    ** it is not possible to write to the database. In this case release
    ** the write locks and return SQLITE_BUSY.
    */
    if( rc==SQLITE_OK ){
      rc = walIndexMap(pWal, sizeof(WalIndexHdr));
      if( rc==SQLITE_OK
       && memcmp(&pWal->hdr, pWal->pWiData, sizeof(WalIndexHdr))
      ){
        rc = SQLITE_BUSY;
      }
      walIndexUnmap(pWal);
      if( rc!=SQLITE_OK ){
        walSetLock(pWal, SQLITE_SHM_READ);
      }
    }
  }else if( pWal->lockState==SQLITE_SHM_WRITE ){
    rc = walSetLock(pWal, SQLITE_SHM_READ);
  }
  return rc;
}

/*
** If any data has been written (but not committed) to the log file, this
** function moves the write-pointer back to the start of the transaction.
**
** Additionally, the callback function is invoked for each frame written
** to the log since the start of the transaction. If the callback returns
** other than SQLITE_OK, it is not invoked again and the error code is
** returned to the caller.
**
** Otherwise, if the callback function does not return an error, this
** function returns SQLITE_OK.
*/
int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
  int rc = SQLITE_OK;
  if( pWal->lockState==SQLITE_SHM_WRITE ){
    int unused;

    Pgno iMax = pWal->hdr.iLastPg;
    Pgno iFrame;
  
    assert( pWal->pWiData==0 );
    rc = walIndexReadHdr(pWal, &unused);
    for(iFrame=pWal->hdr.iLastPg+1; rc==SQLITE_OK && iFrame<=iMax; iFrame++){
      assert( pWal->lockState==SQLITE_SHM_WRITE );
      rc = xUndo(pUndoCtx, pWal->pWiData[walIndexEntry(iFrame)]);
    }
    walIndexUnmap(pWal);
  }
  return rc;
}

/* Return an integer that records the current (uncommitted) write
** position in the WAL
*/
u32 sqlite3WalSavepoint(Wal *pWal){
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
  int rc = SQLITE_OK;
  u8 aCksum[8];
  assert( pWal->lockState==SQLITE_SHM_WRITE );

  pWal->hdr.iLastPg = iFrame;
  if( iFrame>0 ){
    i64 iOffset = walFrameOffset(iFrame, pWal->hdr.pgsz) + sizeof(u32)*2;
    rc = sqlite3OsRead(pWal->pFd, aCksum, sizeof(aCksum), iOffset);
    pWal->hdr.iCheck1 = sqlite3Get4byte(&aCksum[0]);
    pWal->hdr.iCheck2 = sqlite3Get4byte(&aCksum[4]);
  }

  return rc;
}








|







1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
  int rc = SQLITE_OK;
  u8 aCksum[8];
  assert( pWal->lockState==SQLITE_SHM_WRITE );

  pWal->hdr.iLastPg = iFrame;
  if( iFrame>0 ){
    i64 iOffset = walFrameOffset(iFrame, pWal->hdr.pgsz) + sizeof(u32)*2;
    rc = sqlite3OsRead(pWal->pWalFd, aCksum, sizeof(aCksum), iOffset);
    pWal->hdr.iCheck1 = sqlite3Get4byte(&aCksum[0]);
    pWal->hdr.iCheck2 = sqlite3Get4byte(&aCksum[4]);
  }

  return rc;
}

1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
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1351
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1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
  assert( WAL_FRAME_HDRSIZE>=WAL_HDRSIZE );
  iFrame = pWal->hdr.iLastPg;
  if( iFrame==0 ){
    sqlite3Put4byte(aFrame, nPgsz);
    sqlite3_randomness(8, &aFrame[4]);
    pWal->hdr.iCheck1 = sqlite3Get4byte(&aFrame[4]);
    pWal->hdr.iCheck2 = sqlite3Get4byte(&aFrame[8]);
    rc = sqlite3OsWrite(pWal->pFd, aFrame, WAL_HDRSIZE, 0);
    if( rc!=SQLITE_OK ){
      return rc;
    }
  }

  aCksum[0] = pWal->hdr.iCheck1;
  aCksum[1] = pWal->hdr.iCheck2;

  /* Write the log file. */
  for(p=pList; p; p=p->pDirty){
    u32 nDbsize;                  /* Db-size field for frame header */
    i64 iOffset;                  /* Write offset in log file */

    iOffset = walFrameOffset(++iFrame, nPgsz);
    
    /* Populate and write the frame header */
    nDbsize = (isCommit && p->pDirty==0) ? nTruncate : 0;
    walEncodeFrame(aCksum, p->pgno, nDbsize, nPgsz, p->pData, aFrame);
    rc = sqlite3OsWrite(pWal->pFd, aFrame, sizeof(aFrame), iOffset);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    /* Write the page data */
    rc = sqlite3OsWrite(pWal->pFd, p->pData, nPgsz, iOffset + sizeof(aFrame));
    if( rc!=SQLITE_OK ){
      return rc;
    }
    pLast = p;
  }

  /* Sync the log file if the 'isSync' flag was specified. */
  if( sync_flags ){
    i64 iSegment = sqlite3OsSectorSize(pWal->pFd);
    i64 iOffset = walFrameOffset(iFrame+1, nPgsz);

    assert( isCommit );

    if( iSegment<SQLITE_DEFAULT_SECTOR_SIZE ){
      iSegment = SQLITE_DEFAULT_SECTOR_SIZE;
    }
    iSegment = (((iOffset+iSegment-1)/iSegment) * iSegment);
    while( iOffset<iSegment ){
      walEncodeFrame(aCksum,pLast->pgno,nTruncate,nPgsz,pLast->pData,aFrame);
      rc = sqlite3OsWrite(pWal->pFd, aFrame, sizeof(aFrame), iOffset);
      if( rc!=SQLITE_OK ){
        return rc;
      }

      iOffset += WAL_FRAME_HDRSIZE;
      rc = sqlite3OsWrite(pWal->pFd, pLast->pData, nPgsz, iOffset); 
      if( rc!=SQLITE_OK ){
        return rc;
      }
      nLast++;
      iOffset += nPgsz;
    }

    rc = sqlite3OsSync(pWal->pFd, sync_flags);
  }
  assert( pWal->pWiData==0 );

  /* Append data to the log summary. It is not necessary to lock the 
  ** wal-index to do this as the RESERVED lock held on the db file
  ** guarantees that there are no other writers, and no data that may
  ** be in use by existing readers is being overwritten.







|


















|





|








|










|





|







|







1332
1333
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1336
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1339
1340
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1398
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1400
1401
1402
1403
1404
1405
  assert( WAL_FRAME_HDRSIZE>=WAL_HDRSIZE );
  iFrame = pWal->hdr.iLastPg;
  if( iFrame==0 ){
    sqlite3Put4byte(aFrame, nPgsz);
    sqlite3_randomness(8, &aFrame[4]);
    pWal->hdr.iCheck1 = sqlite3Get4byte(&aFrame[4]);
    pWal->hdr.iCheck2 = sqlite3Get4byte(&aFrame[8]);
    rc = sqlite3OsWrite(pWal->pWalFd, aFrame, WAL_HDRSIZE, 0);
    if( rc!=SQLITE_OK ){
      return rc;
    }
  }

  aCksum[0] = pWal->hdr.iCheck1;
  aCksum[1] = pWal->hdr.iCheck2;

  /* Write the log file. */
  for(p=pList; p; p=p->pDirty){
    u32 nDbsize;                  /* Db-size field for frame header */
    i64 iOffset;                  /* Write offset in log file */

    iOffset = walFrameOffset(++iFrame, nPgsz);
    
    /* Populate and write the frame header */
    nDbsize = (isCommit && p->pDirty==0) ? nTruncate : 0;
    walEncodeFrame(aCksum, p->pgno, nDbsize, nPgsz, p->pData, aFrame);
    rc = sqlite3OsWrite(pWal->pWalFd, aFrame, sizeof(aFrame), iOffset);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    /* Write the page data */
    rc = sqlite3OsWrite(pWal->pWalFd, p->pData, nPgsz, iOffset + sizeof(aFrame));
    if( rc!=SQLITE_OK ){
      return rc;
    }
    pLast = p;
  }

  /* Sync the log file if the 'isSync' flag was specified. */
  if( sync_flags ){
    i64 iSegment = sqlite3OsSectorSize(pWal->pWalFd);
    i64 iOffset = walFrameOffset(iFrame+1, nPgsz);

    assert( isCommit );

    if( iSegment<SQLITE_DEFAULT_SECTOR_SIZE ){
      iSegment = SQLITE_DEFAULT_SECTOR_SIZE;
    }
    iSegment = (((iOffset+iSegment-1)/iSegment) * iSegment);
    while( iOffset<iSegment ){
      walEncodeFrame(aCksum,pLast->pgno,nTruncate,nPgsz,pLast->pData,aFrame);
      rc = sqlite3OsWrite(pWal->pWalFd, aFrame, sizeof(aFrame), iOffset);
      if( rc!=SQLITE_OK ){
        return rc;
      }

      iOffset += WAL_FRAME_HDRSIZE;
      rc = sqlite3OsWrite(pWal->pWalFd, pLast->pData, nPgsz, iOffset); 
      if( rc!=SQLITE_OK ){
        return rc;
      }
      nLast++;
      iOffset += nPgsz;
    }

    rc = sqlite3OsSync(pWal->pWalFd, sync_flags);
  }
  assert( pWal->pWiData==0 );

  /* Append data to the log summary. It is not necessary to lock the 
  ** wal-index to do this as the RESERVED lock held on the db file
  ** guarantees that there are no other writers, and no data that may
  ** be in use by existing readers is being overwritten.
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**   1. Acquire a CHECKPOINT lock
**   2. Copy the contents of the log into the database file.
**   3. Zero the wal-index header (so new readers will ignore the log).
**   4. Drop the CHECKPOINT lock.
*/
int sqlite3WalCheckpoint(
  Wal *pWal,                      /* Wal connection */
  sqlite3_file *pFd,              /* File descriptor open on db file */
  int sync_flags,                 /* Flags to sync db file with (or 0) */
  int nBuf,                       /* Size of temporary buffer */
  u8 *zBuf,                       /* Temporary buffer to use */
  int (*xBusyHandler)(void *),    /* Pointer to busy-handler function */
  void *pBusyHandlerArg           /* Argument to pass to xBusyHandler */
){
  int rc;                         /* Return code */
  int isChanged = 0;              /* True if a new wal-index header is loaded */

  assert( pWal->pWiData==0 );

  /* Get the CHECKPOINT lock */





  if( pWal->lockState!=SQLITE_SHM_UNLOCK ){
    /* This can occur when locking_mode=EXCLUSIVE */

    assert( pWal->lockState==SQLITE_SHM_READ
         || pWal->lockState==SQLITE_SHM_READ_FULL );
    walSetLock(pWal, SQLITE_SHM_UNLOCK);
  }
  do {
    rc = walSetLock(pWal, SQLITE_SHM_CHECKPOINT);
  }while( rc==SQLITE_BUSY && xBusyHandler(pBusyHandlerArg) );
  if( rc!=SQLITE_OK ){
    walSetLock(pWal, SQLITE_SHM_UNLOCK);
    return rc;
  }

  /* Copy data from the log to the database file. */
  rc = walIndexReadHdr(pWal, &isChanged);
  if( rc==SQLITE_OK ){
    rc = walCheckpoint(pWal, pFd, sync_flags, nBuf, zBuf);
  }
  if( isChanged ){
    /* If a new wal-index header was loaded before the checkpoint was 
    ** performed, then the pager-cache associated with log pWal is now
    ** out of date. So zero the cached wal-index header to ensure that
    ** next time the pager opens a snapshot on this database it knows that
    ** the cache needs to be reset.







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**   1. Acquire a CHECKPOINT lock
**   2. Copy the contents of the log into the database file.
**   3. Zero the wal-index header (so new readers will ignore the log).
**   4. Drop the CHECKPOINT lock.
*/
int sqlite3WalCheckpoint(
  Wal *pWal,                      /* Wal connection */

  int sync_flags,                 /* Flags to sync db file with (or 0) */
  int nBuf,                       /* Size of temporary buffer */
  u8 *zBuf,                       /* Temporary buffer to use */
  int (*xBusyHandler)(void *),    /* Pointer to busy-handler function */
  void *pBusyHandlerArg           /* Argument to pass to xBusyHandler */
){
  int rc;                         /* Return code */
  int isChanged = 0;              /* True if a new wal-index header is loaded */

  assert( pWal->pWiData==0 );

  /* Get the CHECKPOINT lock. 
  **
  ** Normally, the connection will be in UNLOCK state at this point. But
  ** if the connection is in exclusive-mode it may still be in READ state
  ** even though the upper layer has no active read-transaction (because
  ** WalCloseSnapshot() is not called in exclusive mode). The state will
  ** be set to UNLOCK when this function returns. This is Ok.

  */
  assert( (pWal->lockState==SQLITE_SHM_UNLOCK)
       || (pWal->lockState==SQLITE_SHM_READ) );
  walSetLock(pWal, SQLITE_SHM_UNLOCK);

  do {
    rc = walSetLock(pWal, SQLITE_SHM_CHECKPOINT);
  }while( rc==SQLITE_BUSY && xBusyHandler(pBusyHandlerArg) );
  if( rc!=SQLITE_OK ){
    walSetLock(pWal, SQLITE_SHM_UNLOCK);
    return rc;
  }

  /* Copy data from the log to the database file. */
  rc = walIndexReadHdr(pWal, &isChanged);
  if( rc==SQLITE_OK ){
    rc = walCheckpoint(pWal, sync_flags, nBuf, zBuf);
  }
  if( isChanged ){
    /* If a new wal-index header was loaded before the checkpoint was 
    ** performed, then the pager-cache associated with log pWal is now
    ** out of date. So zero the cached wal-index header to ensure that
    ** next time the pager opens a snapshot on this database it knows that
    ** the cache needs to be reset.
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  u32 ret = 0;
  if( pWal ){
    ret = pWal->iCallback;
    pWal->iCallback = 0;
  }
  return (int)ret;
}































#endif /* #ifndef SQLITE_OMIT_WAL */







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  u32 ret = 0;
  if( pWal ){
    ret = pWal->iCallback;
    pWal->iCallback = 0;
  }
  return (int)ret;
}

/*
** This function is called to set or query the exclusive-mode flag 
** associated with the WAL connection passed as the first argument. The
** exclusive-mode flag should be set to indicate that the caller is
** holding an EXCLUSIVE lock on the database file (it does this in
** locking_mode=exclusive mode). If the EXCLUSIVE lock is to be dropped,
** the flag set by this function should be cleared before doing so.
**
** The value of the exclusive-mode flag may only be modified when
** the WAL connection is in READ state.
**
** When the flag is set, this module does not call the VFS xShmLock()
** method to obtain any locks on the wal-index (as it assumes it
** has exclusive access to the wal and wal-index files anyhow). It
** continues to hold (and does not drop) the existing READ lock on
** the wal-index.
**
** To set or clear the flag, the "op" parameter is passed 1 or 0,
** respectively. To query the flag, pass -1. In all cases, the value
** returned is the value of the exclusive-mode flag (after its value
** has been modified, if applicable).
*/
int sqlite3WalExclusiveMode(Wal *pWal, int op){
  if( op>=0 ){
    assert( pWal->lockState==SQLITE_SHM_READ );
    pWal->exclusiveMode = (u8)op;
  }
  return pWal->exclusiveMode;
}

#endif /* #ifndef SQLITE_OMIT_WAL */
Changes to src/wal.h.
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/* Connection to a write-ahead log (WAL) file. 
** There is one object of this type for each pager. 
*/
typedef struct Wal Wal;

/* Open and close a connection to a write-ahead log. */
int sqlite3WalOpen(sqlite3_vfs*, const char *zDb, Wal **ppWal);
int sqlite3WalClose(Wal *pWal, sqlite3_file *pFd, int sync_flags, int, u8 *);

/* Used by readers to open (lock) and close (unlock) a snapshot.  A 
** snapshot is like a read-transaction.  It is the state of the database
** at an instant in time.  sqlite3WalOpenSnapshot gets a read lock and
** preserves the current state even if the other threads or processes
** write to or checkpoint the WAL.  sqlite3WalCloseSnapshot() closes the
** transaction and releases the lock.







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/* Connection to a write-ahead log (WAL) file. 
** There is one object of this type for each pager. 
*/
typedef struct Wal Wal;

/* Open and close a connection to a write-ahead log. */
int sqlite3WalOpen(sqlite3_vfs*, sqlite3_file*, const char *zName, Wal**);
int sqlite3WalClose(Wal *pWal, int sync_flags, int, u8 *);

/* Used by readers to open (lock) and close (unlock) a snapshot.  A 
** snapshot is like a read-transaction.  It is the state of the database
** at an instant in time.  sqlite3WalOpenSnapshot gets a read lock and
** preserves the current state even if the other threads or processes
** write to or checkpoint the WAL.  sqlite3WalCloseSnapshot() closes the
** transaction and releases the lock.
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/* Write a frame or frames to the log. */
int sqlite3WalFrames(Wal *pWal, int, PgHdr *, Pgno, int, int);

/* Copy pages from the log to the database file */ 
int sqlite3WalCheckpoint(
  Wal *pWal,                      /* Write-ahead log connection */
  sqlite3_file *pFd,              /* File descriptor open on db file */
  int sync_flags,                 /* Flags to sync db file with (or 0) */
  int nBuf,                       /* Size of buffer nBuf */
  u8 *zBuf,                       /* Temporary buffer to use */
  int (*xBusyHandler)(void *),    /* Pointer to busy-handler function */
  void *pBusyHandlerArg           /* Argument to pass to xBusyHandler */
);

/* Return the value to pass to a sqlite3_wal_hook callback, the
** number of frames in the WAL at the point of the last commit since
** sqlite3WalCallback() was called.  If no commits have occurred since
** the last call, then return 0.
*/
int sqlite3WalCallback(Wal *pWal);






#endif /* ifndef SQLITE_OMIT_WAL */
#endif /* _WAL_H_ */







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/* Write a frame or frames to the log. */
int sqlite3WalFrames(Wal *pWal, int, PgHdr *, Pgno, int, int);

/* Copy pages from the log to the database file */ 
int sqlite3WalCheckpoint(
  Wal *pWal,                      /* Write-ahead log connection */

  int sync_flags,                 /* Flags to sync db file with (or 0) */
  int nBuf,                       /* Size of buffer nBuf */
  u8 *zBuf,                       /* Temporary buffer to use */
  int (*xBusyHandler)(void *),    /* Pointer to busy-handler function */
  void *pBusyHandlerArg           /* Argument to pass to xBusyHandler */
);

/* Return the value to pass to a sqlite3_wal_hook callback, the
** number of frames in the WAL at the point of the last commit since
** sqlite3WalCallback() was called.  If no commits have occurred since
** the last call, then return 0.
*/
int sqlite3WalCallback(Wal *pWal);

/* Tell the wal layer that an EXCLUSIVE lock has been obtained (or released)
** by the pager layer on the database file.
*/
int sqlite3WalExclusiveMode(Wal *pWal, int op);

#endif /* ifndef SQLITE_OMIT_WAL */
#endif /* _WAL_H_ */
Changes to test/tester.tcl.
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proc ostrace_call {zCall nClick zFile i32 i64} {
  set s "INSERT INTO ostrace VALUES('$zCall', $nClick, '$zFile', $i32, $i64);"
  puts $::ostrace_fd $s
}

for {set i 0} {$i<[llength $argv]} {incr i} {
  if {[lindex $argv $i] eq "--ossummary" || [lindex $argv $i] eq "--ostrace"} {
    sqlite3_instvfs create -default ostrace
    set tester_do_ostrace 1
    set ostrace_fd [open ostrace.sql w]
    puts $ostrace_fd "BEGIN;"
    if {[lindex $argv $i] eq "--ostrace"} {
      set    s "CREATE TABLE ostrace"
      append s "(method TEXT, clicks INT, file TEXT, i32 INT, i64 INT);"
      puts $ostrace_fd $s
      sqlite3_instvfs configure ostrace ostrace_call
      sqlite3_instvfs configure ostrace ostrace_call
    }
    set argv [lreplace $argv $i $i]
  }
  if {[lindex $argv $i] eq "--binarylog"} {
    set tester_do_binarylog 1
    set argv [lreplace $argv $i $i]
  }
}

# 







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proc ostrace_call {zCall nClick zFile i32 i64} {
  set s "INSERT INTO ostrace VALUES('$zCall', $nClick, '$zFile', $i32, $i64);"
  puts $::ostrace_fd $s
}

for {set i 0} {$i<[llength $argv]} {incr i} {














  if {[lindex $argv $i] eq "--binarylog"} {
    set tester_do_binarylog 1
    set argv [lreplace $argv $i $i]
  }
}

# 
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#
if {![info exists nTest]} {
  sqlite3_shutdown 
  install_malloc_faultsim 1 
  sqlite3_initialize
  autoinstall_test_functions
  if {[info exists tester_do_binarylog]} {
    sqlite3_instvfs binarylog -default binarylog ostrace.bin
    sqlite3_instvfs marker binarylog "$argv0 $argv"
  }
}

proc reset_db {} {
  catch {db close}
  file delete -force test.db
  file delete -force test.db-journal







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#
if {![info exists nTest]} {
  sqlite3_shutdown 
  install_malloc_faultsim 1 
  sqlite3_initialize
  autoinstall_test_functions
  if {[info exists tester_do_binarylog]} {
    vfslog new binarylog {} vfslog.bin
    #sqlite3_instvfs marker binarylog "$argv0 $argv"
  }
}

proc reset_db {} {
  catch {db close}
  file delete -force test.db
  file delete -force test.db-journal
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# Invoke the do_test procedure to run a single test 
#
proc do_test {name cmd expected} {
  global argv nErr nTest skip_test maxErr
  sqlite3_memdebug_settitle $name
  if {[info exists ::tester_do_binarylog]} {
    sqlite3_instvfs marker binarylog "Start of $name"
  }
  if {$skip_test} {
    set skip_test 0
    return
  }
  if {[llength $argv]==0} { 
    set go 1







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# Invoke the do_test procedure to run a single test 
#
proc do_test {name cmd expected} {
  global argv nErr nTest skip_test maxErr
  sqlite3_memdebug_settitle $name
  if {[info exists ::tester_do_binarylog]} {
    #sqlite3_instvfs marker binarylog "Start of $name"
  }
  if {$skip_test} {
    set skip_test 0
    return
  }
  if {[llength $argv]==0} { 
    set go 1
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    lappend ::failList $name
    if {$nErr>=$maxErr} {puts "*** Giving up..."; finalize_testing}
  } else {
    puts " Ok"
  }
  flush stdout
  if {[info exists ::tester_do_binarylog]} {
    sqlite3_instvfs marker binarylog "End of $name"
  }
}

# Run an SQL script.  
# Return the number of microseconds per statement.
#
proc speed_trial {name numstmt units sql} {







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    lappend ::failList $name
    if {$nErr>=$maxErr} {puts "*** Giving up..."; finalize_testing}
  } else {
    puts " Ok"
  }
  flush stdout
  if {[info exists ::tester_do_binarylog]} {
    #sqlite3_instvfs marker binarylog "End of $name"
  }
}

# Run an SQL script.  
# Return the number of microseconds per statement.
#
proc speed_trial {name numstmt units sql} {
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    puts "N.B.:  The version of TCL that you used to build this test harness"
    puts "is defective in that it does not support 64-bit integers.  Some or"
    puts "all of the test failures above might be a result from this defect"
    puts "in your TCL build."
    puts "******************************************************************"
  }
  if {[info exists ::tester_do_binarylog]} {
    sqlite3_instvfs destroy binarylog
  }
  if {$sqlite_open_file_count} {
    puts "$sqlite_open_file_count files were left open"
    incr nErr
  }
  if {[info exists ::tester_do_ostrace]} {
    puts "Writing ostrace.sql..."
    set fd $::ostrace_fd

    puts -nonewline $fd "CREATE TABLE ossummary"
    puts $fd "(method TEXT, clicks INTEGER, count INTEGER);"
    foreach row [sqlite3_instvfs report ostrace] {
      foreach {method count clicks} $row break
      puts $fd "INSERT INTO ossummary VALUES('$method', $clicks, $count);"
    }
    puts $fd "COMMIT;"
    close $fd
    sqlite3_instvfs destroy ostrace
  }
  if {[sqlite3_memory_used]>0} {
    puts "Unfreed memory: [sqlite3_memory_used] bytes"
    incr nErr
    ifcapable memdebug||mem5||(mem3&&debug) {
      puts "Writing unfreed memory log to \"./memleak.txt\""
      sqlite3_memdebug_dump ./memleak.txt
    }







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    puts "N.B.:  The version of TCL that you used to build this test harness"
    puts "is defective in that it does not support 64-bit integers.  Some or"
    puts "all of the test failures above might be a result from this defect"
    puts "in your TCL build."
    puts "******************************************************************"
  }
  if {[info exists ::tester_do_binarylog]} {
    vfslog finalize binarylog
  }
  if {$sqlite_open_file_count} {
    puts "$sqlite_open_file_count files were left open"
    incr nErr
  }














  if {[sqlite3_memory_used]>0} {
    puts "Unfreed memory: [sqlite3_memory_used] bytes"
    incr nErr
    ifcapable memdebug||mem5||(mem3&&debug) {
      puts "Writing unfreed memory log to \"./memleak.txt\""
      sqlite3_memdebug_dump ./memleak.txt
    }
Changes to test/thread2.test.
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# Skip this whole file if the thread testing code is not enabled
#
if {[llength [info command thread_step]]==0 || [sqlite3 -has-codec]} {
  finish_test
  return
}
if {![info exists threadsOverrideEachOthersLocks]} {
  finish_test
  return
}

# Create some data to work with
#
do_test thread1-1.1 {
  execsql {
    CREATE TABLE t1(a,b);
    INSERT INTO t1 VALUES(1,'abcdefgh');







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# Skip this whole file if the thread testing code is not enabled
#
if {[llength [info command thread_step]]==0 || [sqlite3 -has-codec]} {
  finish_test
  return
}





# Create some data to work with
#
do_test thread1-1.1 {
  execsql {
    CREATE TABLE t1(a,b);
    INSERT INTO t1 VALUES(1,'abcdefgh');
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do_test thread2-2.9 {
  thread_finalize B
  thread_result B
} {SQLITE_OK}
thread_halt A
thread_halt B

# Save the original (correct) value of threadsOverrideEachOthersLocks
# so that it can be restored.  If this value is left set incorrectly, lots
# of things will go wrong in future tests.
#
set orig_threadOverride $threadsOverrideEachOthersLocks

# Pretend we are on a system (like RedHat9) were threads do not
# override each others locks.
#
set threadsOverrideEachOthersLocks 0

# Verify that we can move database connections between threads as
# long as no locks are held.
#
do_test thread2-3.1 {
  thread_create A test.db
  set DB [thread_db_get A]
  thread_halt A
} {}
do_test thread2-3.2 {
  set STMT [sqlite3_prepare $DB {SELECT a FROM t1 LIMIT 1} -1 TAIL]
  sqlite3_step $STMT
} SQLITE_ROW
do_test thread2-3.3 {
  sqlite3_column_int $STMT 0
} 1
do_test thread2-3.4 {
  sqlite3_finalize $STMT
} SQLITE_OK
do_test thread2-3.5 {
  set STMT [sqlite3_prepare $DB {SELECT max(a) FROM t1} -1 TAIL]
  sqlite3_step $STMT
} SQLITE_ROW
do_test thread2-3.6 {
  sqlite3_column_int $STMT 0
} 8
do_test thread2-3.7 {
  sqlite3_finalize $STMT
} SQLITE_OK
do_test thread2-3.8 {
  sqlite3_close $DB
} {SQLITE_OK}

do_test thread2-3.10 {
  thread_create A test.db
  thread_compile A {SELECT a FROM t1 LIMIT 1}
  thread_step A
  thread_finalize A
  set DB [thread_db_get A]
  thread_halt A
} {}
do_test thread2-3.11 {
  set STMT [sqlite3_prepare $DB {SELECT a FROM t1 LIMIT 1} -1 TAIL]
  sqlite3_step $STMT
} SQLITE_ROW
do_test thread2-3.12 {
  sqlite3_column_int $STMT 0
} 1
do_test thread2-3.13 {
  sqlite3_finalize $STMT
} SQLITE_OK
do_test thread2-3.14 {
  sqlite3_close $DB
} SQLITE_OK

do_test thread2-3.20 {
  thread_create A test.db
  thread_compile A {SELECT a FROM t1 LIMIT 3}
  thread_step A
  set STMT [thread_stmt_get A]
  set DB [thread_db_get A]
  sqlite3_step $STMT
} SQLITE_ROW
do_test thread2-3.22 {
  sqlite3_column_int $STMT 0
} 2
do_test thread2-3.23 {
  # The unlock fails here.  But because we never check the return
  # code from sqlite3OsUnlock (because we cannot do anything about it
  # if it fails) we do not realize that an error has occurred.
  breakpoint
  sqlite3_finalize $STMT
} SQLITE_OK
do_test thread2-3.25 {
  thread_db_put A $DB
  thread_halt A
} {}

do_test thread2-3.30 {
  thread_create A test.db
  thread_compile A {BEGIN}
  thread_step A
  thread_finalize A
  thread_compile A {SELECT a FROM t1 LIMIT 1}
  thread_step A
  thread_finalize A
  set DB [thread_db_get A]
  set STMT [sqlite3_prepare $DB {INSERT INTO t1 VALUES(99,'error')} -1 TAIL]
  sqlite3_step $STMT
} SQLITE_ERROR
do_test thread2-3.32 {
  sqlite3_finalize $STMT
} SQLITE_MISUSE
do_test thread2-3.33 {
  thread_db_put A $DB
  thread_halt A
} {}

# VERY important to set the override flag back to its true value.
#
set threadsOverrideEachOthersLocks $orig_threadOverride

# Also important to halt the worker threads, which are using spin
# locks and eating away CPU cycles.
#
thread_halt *   
finish_test







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do_test thread2-2.9 {
  thread_finalize B
  thread_result B
} {SQLITE_OK}
thread_halt A
thread_halt B

















































































































# Also important to halt the worker threads, which are using spin
# locks and eating away CPU cycles.
#
thread_halt *   
finish_test
Added test/tkt-26ff0c2d1e.test.


































































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# 2010 May 12
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script testing a bug found in the OP_Variable optimizer
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

do_test bug-20100512-1 {
  set DB [sqlite3_connection_pointer db]
  set SQL {SELECT case when 1 then 99 else ? end + ?}
  set STMT [sqlite3_prepare_v2 $DB $SQL -1 TAIL]
  set TAIL
} {}
do_test bug-20100512-2 {
  sqlite3_bind_parameter_count $STMT
} 2
do_test bug-20100512-3 {
  sqlite3_bind_int $STMT 1 123
  sqlite3_bind_int $STMT 2 456
  sqlite3_step $STMT
  sqlite3_column_int $STMT 0
} {555}
sqlite3_finalize $STMT
Deleted test/tkt3472.test.
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# 2008 November 11
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#     
# $Id: tkt3472.test,v 1.4 2008/12/03 22:32:45 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

if {![info exists threadsOverrideEachOthersLocks]} {
  finish_test
  return
}

set ::correctvalue $threadsOverrideEachOthersLocks
puts "threadsOverrideEachOthersLocks = $::correctvalue"

do_test tkt3472-1.1 {
  db close
  set threadsOverrideEachOthersLocks -1
  sqlite3 db test.db
  set threadsOverrideEachOthersLocks
} $::correctvalue

do_test tkt3472-1.2 {
  db close
  set threadsOverrideEachOthersLocks -1
  sqlite3 db test.db -readonly 1
  set threadsOverrideEachOthersLocks
} $::correctvalue

finish_test
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  }

  incr_tvfs_hdr $::shm_file 1 1
  set ::locks [list]
  execsql { PRAGMA wal_checkpoint }
  set ::locks
} {CHECKPOINT UNLOCK}























































db close





























































































































































tvfs delete


























finish_test








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  }

  incr_tvfs_hdr $::shm_file 1 1
  set ::locks [list]
  execsql { PRAGMA wal_checkpoint }
  set ::locks
} {CHECKPOINT UNLOCK}
db close
tvfs delete

#-------------------------------------------------------------------------
# This block, test cases wal2-6.*, tests the operation of WAL with
# "PRAGMA locking_mode=EXCLUSIVE" set.
#
#   wal2-6.1.*: Changing to WAL mode before setting locking_mode=exclusive.
#
#   wal2-6.2.*: Changing to WAL mode after setting locking_mode=exclusive.
#
#   wal2-6.3.*: Changing back to rollback mode from WAL mode after setting 
#               locking_mode=exclusive.
#
#   wal2-6.4.*: Check that xShmLock calls are omitted in exclusive locking
#               mode.
#
do_test wal2-6.1.1 {
  file delete -force test.db test.db-wal test.db-journal
  sqlite3 db test.db
  execsql {
    Pragma Journal_Mode = Wal;
    Pragma Locking_Mode = Exclusive;
  }
} {wal exclusive}
do_test wal2-6.1.2 {
  execsql { PRAGMA lock_status }
} {main unlocked temp closed}
do_test wal2-6.1.3 {
  execsql {
    BEGIN;
      CREATE TABLE t1(a, b);
      INSERT INTO t1 VALUES(1, 2);
    COMMIT;
    PRAGMA lock_status;
  }
} {main exclusive temp closed}
do_test wal2-6.1.4 {
  execsql { 
    PRAGMA locking_mode = normal; 
    PRAGMA lock_status;
  }
} {normal main exclusive temp closed}
do_test wal2-6.1.5 {
  execsql { 
    SELECT * FROM t1;
    PRAGMA lock_status;
  }
} {1 2 main exclusive temp closed}
do_test wal2-6.1.6 {
  execsql {
    INSERT INTO t1 VALUES(3, 4);
    PRAGMA lock_status;
  }
} {main shared temp closed}
db close

do_test wal2-6.2.1 {
  file delete -force test.db test.db-wal test.db-journal
  sqlite3 db test.db
  execsql {
    Pragma Locking_Mode = Exclusive;
    Pragma Journal_Mode = Wal;
    Pragma Lock_Status;
  }
} {exclusive wal main exclusive temp closed}
do_test wal2-6.2.2 {
  execsql {
    BEGIN;
      CREATE TABLE t1(a, b);
      INSERT INTO t1 VALUES(1, 2);
    COMMIT;
    Pragma loCK_STATus;
  }
} {main exclusive temp closed}
do_test wal2-6.2.3 {
  db close
  sqlite3 db test.db
  execsql { PRAGMA LOCKING_MODE = EXCLUSIVE }
} {exclusive}
do_test wal2-6.2.4 {
  execsql {
    SELECT * FROM t1;
    pragma lock_status;
  }
} {1 2 main shared temp closed}
do_test wal2-6.2.5 {
  execsql {
    INSERT INTO t1 VALUES(3, 4);
    pragma lock_status;
  }
} {main exclusive temp closed}
do_test wal2-6.2.6 {
  execsql {
    PRAGMA locking_mode = NORMAL;
    pragma lock_status;
  }
} {normal main exclusive temp closed}
do_test wal2-6.2.7 {
  execsql {
    BEGIN IMMEDIATE; COMMIT;
    pragma lock_status;
  }
} {main shared temp closed}
do_test wal2-6.2.8 {
  execsql {
    PRAGMA locking_mode = EXCLUSIVE;
    BEGIN IMMEDIATE; COMMIT;
    PRAGMA locking_mode = NORMAL;
  }
  execsql {
    SELECT * FROM t1;
    pragma lock_status;
  }
} {1 2 3 4 main exclusive temp closed}
do_test wal2-6.2.9 {
  execsql {
    INSERT INTO t1 VALUES(5, 6);
    SELECT * FROM t1;
    pragma lock_status;
  }
} {1 2 3 4 5 6 main shared temp closed}
db close

do_test wal2-6.3.1 {
  file delete -force test.db test.db-wal test.db-journal
  sqlite3 db test.db
  execsql {
    PRAGMA journal_mode = WAL;
    PRAGMA locking_mode = exclusive;
    BEGIN;
      CREATE TABLE t1(x);
      INSERT INTO t1 VALUES('Chico');
      INSERT INTO t1 VALUES('Harpo');
    COMMIT;
  }
  list [file exists test.db-wal] [file exists test.db-journal]
} {1 0}
do_test wal2-6.3.2 {
  execsql { PRAGMA journal_mode = DELETE }
  file exists test.db-wal
} {0}
do_test wal2-6.3.3 {
  execsql { PRAGMA lock_status }
} {main exclusive temp closed}
do_test wal2-6.3.4 {
  execsql { 
    BEGIN;
      INSERT INTO t1 VALUES('Groucho');
  }
  list [file exists test.db-wal] [file exists test.db-journal]
} {0 1}
do_test wal2-6.3.5 {
  execsql { PRAGMA lock_status }
} {main exclusive temp closed}
do_test wal2-6.3.6 {
  execsql { COMMIT }
  list [file exists test.db-wal] [file exists test.db-journal]
} {0 1}
do_test wal2-6.3.7 {
  execsql { PRAGMA lock_status }
} {main exclusive temp closed}
db close

do_test wal2-6.4.1 {
  file delete -force test.db test.db-wal test.db-journal
  proc tvfs_cb {method args} {
    set ::shm_file [lindex $args 0]
    if {$method == "xShmLock"} { lappend ::locks [lindex $args 2] }
    return "SQLITE_OK"
  }
  testvfs tvfs tvfs_cb
  sqlite3 db test.db -vfs tvfs

  execsql {
    PRAGMA journal_mode = WAL;
    CREATE TABLE t1(x);
    INSERT INTO t1 VALUES('Leonard');
    INSERT INTO t1 VALUES('Arthur');
  }

  set ::locks [list]
  execsql { PRAGMA locking_mode = exclusive }
  set ::locks
} {}
do_test wal2-6.4.2 {
  execsql { SELECT * FROM t1 }
} {Leonard Arthur}
do_test wal2-6.4.3 {
  set ::locks
} {READ}
do_test wal2-6.4.4 {
  execsql { 
    INSERT INTO t1 VALUES('Julius Henry');
    SELECT * FROM t1;
  }
} {Leonard Arthur {Julius Henry}}
do_test wal2-6.4.5 {
  set ::locks
} {READ}
do_test wal2-6.4.6 {
  execsql {
    PRAGMA locking_mode = NORMAL;
    DELETE FROM t1;
  }
  set ::locks
} {READ UNLOCK}
do_test wal2-6.4.7 {
  set ::locks [list]
  execsql { INSERT INTO t1 VALUES('Karl') }
  set ::locks
} {READ WRITE READ UNLOCK}
db close
tvfs delete

do_test wal2-6.5.1 {
  sqlite3 db test.db
  execsql {
    PRAGMA journal_mode = wal;
    PRAGMA locking_mode = exclusive;
    CREATE TABLE t2(a, b);
    PRAGMA wal_checkpoint;
    INSERT INTO t2 VALUES('I', 'II');
    PRAGMA journal_mode;
  }
} {wal exclusive wal}
do_test wal2-6.5.2 {
  execsql {
    PRAGMA locking_mode = normal;
    INSERT INTO t2 VALUES('III', 'IV');
    PRAGMA locking_mode = exclusive;
    SELECT * FROM t2;
  }
} {normal exclusive I II III IV}
do_test wal2-6.5.3 {
  execsql { PRAGMA wal_checkpoint }
} {}

db close

finish_test