** 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: btree.c,v 1.406 2007/08/21 19:33:56 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

................................................................................
/*
** Set this global variable to 1 to enable tracing using the TRACE
** macro.
*/
#if SQLITE_TEST
int sqlite3_btree_trace=0;  /* True to enable tracing */
#endif



#ifndef SQLITE_OMIT_SHARED_CACHE
/*
** A flag to indicate whether or not shared cache is enabled.  Also,
** a list of BtShared objects that are eligible for participation
** in shared cache.  The variables have file scope during normal builds,
** but the test harness needs to access these variables so make them
** global for test builds.
*/
#ifdef SQLITE_TEST
BtShared *sqlite3SharedCacheList = 0;
int sqlite3SharedCacheEnabled = 0;
#else
static BtShared *sqlite3SharedCacheList = 0;

** 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: btree.c,v 1.407 2007/08/22 00:39:20 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

................................................................................
/*
** Set this global variable to 1 to enable tracing using the TRACE
** macro.
*/
#if SQLITE_TEST
int sqlite3_btree_trace=0;  /* True to enable tracing */
#endif



#ifndef SQLITE_OMIT_SHARED_CACHE
/*
** A flag to indicate whether or not shared cache is enabled.  Also,
** a list of BtShared objects that are eligible for participation
** in shared cache.  The variables have file scope during normal builds,
** but the test harness needs to access these variables so we make them
** global for test builds.
*/
#ifdef SQLITE_TEST
BtShared *sqlite3SharedCacheList = 0;
int sqlite3SharedCacheEnabled = 0;
#else
static BtShared *sqlite3SharedCacheList = 0;

** 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: btreeInt.h,v 1.8 2007/08/20 22:48:42 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
  int maxLeaf;          /* Maximum local payload in a LEAFDATA table */
  int minLeaf;          /* Minimum local payload in a LEAFDATA table */
  BusyHandler *pBusyHandler;   /* Callback for when there is lock contention */
  u8 inTransaction;     /* Transaction state */
  int nTransaction;     /* Number of open transactions (read + write) */
  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */

#ifndef SQLITE_OMIT_SHARED_CACHE
  int nRef;             /* Number of references to this structure */
  BtShared *pNext;      /* Next on a list of sharable BtShared structs */
  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this struct */
  BtLock *pLock;        /* List of locks held on this shared-btree struct */
#endif
};

/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure

** 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: btreeInt.h,v 1.9 2007/08/22 00:39:20 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
  int maxLeaf;          /* Maximum local payload in a LEAFDATA table */
  int minLeaf;          /* Minimum local payload in a LEAFDATA table */
  BusyHandler *pBusyHandler;   /* Callback for when there is lock contention */
  u8 inTransaction;     /* Transaction state */
  int nTransaction;     /* Number of open transactions (read + write) */
  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this struct */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nRef;             /* Number of references to this structure */
  BtShared *pNext;      /* Next on a list of sharable BtShared structs */

  BtLock *pLock;        /* List of locks held on this shared-btree struct */
#endif
};

/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.393 2007/08/21 19:33:56 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The version of the library
*/
................................................................................
*/
const char *sqlite3_errmsg(sqlite3 *db){
  const char *z;
  if( !db ){
    return sqlite3ErrStr(SQLITE_NOMEM);
  }
  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  if( sqlite3SafetyCheck(db) || db->errCode==SQLITE_MISUSE ){
    return sqlite3ErrStr(SQLITE_MISUSE);
  }

  z = (char*)sqlite3_value_text(db->pErr);
  if( z==0 ){
    z = sqlite3ErrStr(db->errCode);
  }
  sqlite3_mutex_leave(db->mutex);
  return z;
}

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.394 2007/08/22 00:39:20 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The version of the library
*/
................................................................................
*/
const char *sqlite3_errmsg(sqlite3 *db){
  const char *z;
  if( !db ){
    return sqlite3ErrStr(SQLITE_NOMEM);
  }
  sqlite3_mutex_enter(db->mutex);

  if( sqlite3SafetyCheck(db) || db->errCode==SQLITE_MISUSE ){
    return sqlite3ErrStr(SQLITE_MISUSE);
  }
  assert( !db->mallocFailed );
  z = (char*)sqlite3_value_text(db->pErr);
  if( z==0 ){
    z = sqlite3ErrStr(db->errCode);
  }
  sqlite3_mutex_leave(db->mutex);
  return z;
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Memory allocation functions used throughout sqlite.
**
**
** $Id: malloc.c,v 1.8 2007/08/21 19:33:56 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** This routine runs when the memory allocator sees that the
................................................................................
  }
}

/*
** Release memory held by SQLite instances created by the current thread.
*/
int sqlite3_release_memory(int n){
#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
  return sqlite3PagerReleaseMemory(n);
#else
  return SQLITE_OK;
#endif
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Memory allocation functions used throughout sqlite.
**
**
** $Id: malloc.c,v 1.9 2007/08/22 00:39:20 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** This routine runs when the memory allocator sees that the
................................................................................
  }
}

/*
** Release memory held by SQLite instances created by the current thread.
*/
int sqlite3_release_memory(int n){
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  return sqlite3PagerReleaseMemory(n);
#else
  return SQLITE_OK;
#endif
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement mutexes for
** use by the SQLite core.
**
** $Id: mutex.c,v 1.6 2007/08/21 10:44:16 drh Exp $
*/
/*
** If SQLITE_MUTEX_APPDEF is defined, then this whole module is
** omitted and equivalent functionality must be provided by the
** application that links against the SQLite library.
*/
#ifndef SQLITE_MUTEX_APPDEF
................................................................................

/*
** The sqlite3_mutex_alloc() routine allocates a new
** mutex and returns a pointer to it.  If it returns NULL
** that means that a mutex could not be allocated. 
*/
sqlite3_mutex *sqlite3_mutex_alloc(int id){
  static sqlite3_mutex aStatic[3];
  sqlite3_mutex *pNew = 0;
  switch( id ){
    case SQLITE_MUTEX_FAST:
    case SQLITE_MUTEX_RECURSIVE: {
      pNew = sqlite3_malloc(sizeof(*pNew));
      if( pNew ){
        pNew->id = id;
        pNew->cnt = 0;
      }
      break;
    }
    default: {


      pNew = &aStatic[id-SQLITE_MUTEX_STATIC_MASTER];
      pNew->id = id;
      break;
    }
  }
  return pNew;
}
................................................................................
** the same type number.
*/
sqlite3_mutex *sqlite3_mutex_alloc(int iType){
  static sqlite3_mutex staticMutexes[] = {
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },

  };
  sqlite3_mutex *p;
  switch( iType ){
    case SQLITE_MUTEX_FAST: {
      p = sqlite3MallocZero( sizeof(*p) );
      if( p ){
        p->id = iType;
................................................................................
        pthread_mutex_init(&px->auxMutex, 0);
        pthread_mutex_init(&px->mainMutex, 0);
        px->nRef = 0;
      }
      break;
    }
    default: {


      p = &staticMutexes[iType-2];
      p->id = iType;
      break;
    }
  }
  return p;
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement mutexes for
** use by the SQLite core.
**
** $Id: mutex.c,v 1.7 2007/08/22 00:39:20 drh Exp $
*/
/*
** If SQLITE_MUTEX_APPDEF is defined, then this whole module is
** omitted and equivalent functionality must be provided by the
** application that links against the SQLite library.
*/
#ifndef SQLITE_MUTEX_APPDEF
................................................................................

/*
** The sqlite3_mutex_alloc() routine allocates a new
** mutex and returns a pointer to it.  If it returns NULL
** that means that a mutex could not be allocated. 
*/
sqlite3_mutex *sqlite3_mutex_alloc(int id){
  static sqlite3_mutex aStatic[4];
  sqlite3_mutex *pNew = 0;
  switch( id ){
    case SQLITE_MUTEX_FAST:
    case SQLITE_MUTEX_RECURSIVE: {
      pNew = sqlite3_malloc(sizeof(*pNew));
      if( pNew ){
        pNew->id = id;
        pNew->cnt = 0;
      }
      break;
    }
    default: {
      assert( id-SQLITE_MUTEX_STATIC_MASTER >= 0 );
      assert( id-SQLITE_MUTEX_STATIC_MASTER < count(aStatic) );
      pNew = &aStatic[id-SQLITE_MUTEX_STATIC_MASTER];
      pNew->id = id;
      break;
    }
  }
  return pNew;
}
................................................................................
** the same type number.
*/
sqlite3_mutex *sqlite3_mutex_alloc(int iType){
  static sqlite3_mutex staticMutexes[] = {
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
  };
  sqlite3_mutex *p;
  switch( iType ){
    case SQLITE_MUTEX_FAST: {
      p = sqlite3MallocZero( sizeof(*p) );
      if( p ){
        p->id = iType;
................................................................................
        pthread_mutex_init(&px->auxMutex, 0);
        pthread_mutex_init(&px->mainMutex, 0);
        px->nRef = 0;
      }
      break;
    }
    default: {
      assert( iType-2 >= 0 );
      assert( iType-2 < count(staticMutexes) );
      p = &staticMutexes[iType-2];
      p->id = iType;
      break;
    }
  }
  return p;
}

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.364 2007/08/21 14:27:02 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*
................................................................................
#ifdef SQLITE_HAS_CODEC
  void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
  void *pCodecArg;            /* First argument to xCodec() */
#endif
  int nHash;                  /* Size of the pager hash table */
  PgHdr **aHash;              /* Hash table to map page number to PgHdr */
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  Pager *pNext;               /* Linked list of pagers in this thread */



#endif
  char *pTmpSpace;            /* Pager.pageSize bytes of space for tmp use */
  char dbFileVers[16];        /* Changes whenever database file changes */
};

/*
** The following global variables hold counters used for
................................................................................
int sqlite3_pager_writej_count = 0;    /* Number of pages written to journal */
int sqlite3_pager_pgfree_count = 0;    /* Number of cache pages freed */
# define PAGER_INCR(v)  v++
#else
# define PAGER_INCR(v)
#endif












/*
** Journal files begin with the following magic string.  The data
** was obtained from /dev/random.  It is used only as a sanity check.
**
** Since version 2.8.0, the journal format contains additional sanity
................................................................................
#define PAGER_MJ_PGNO(x) ((PENDING_BYTE/((x)->pageSize))+1)

/*
** The maximum legal page number is (2^31 - 1).
*/
#define PAGER_MAX_PGNO 2147483647

































/*
** Enable reference count tracking (for debugging) here:
*/
#ifdef SQLITE_DEBUG
  int pager3_refinfo_enable = 0;
  static void pager_refinfo(PgHdr *p){
    static int cnt = 0;
................................................................................
** automatically when it is closed.
**
** If zFilename is ":memory:" then all information is held in cache.
** It is never written to disk.  This can be used to implement an
** in-memory database.
*/
int sqlite3PagerOpen(
  sqlite3_vfs *pVfs,
  Pager **ppPager,         /* Return the Pager structure here */
  const char *zFilename,   /* Name of the database file to open */
  int nExtra,              /* Extra bytes append to each in-memory page */
  int flags                /* flags controlling this file */
){
  u8 *pPtr;
  Pager *pPager = 0;
................................................................................
  int i;
  int tempFile = 0;
  int memDb = 0;
  int readOnly = 0;
  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
  int noReadlock = (flags & PAGER_NO_READLOCK)!=0;

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  /* A malloc() cannot fail in sqlite3ThreadData() as one or more calls to 
  ** malloc() must have already been made by this thread before it gets
  ** to this point. This means the ThreadData must have been allocated already
  ** so that ThreadData.nAlloc can be set. It would be nice to assert
  ** that ThreadData.nAlloc is non-zero, but alas this breaks test cases 
  ** written to invoke the pager directly.
  */
  ThreadData *pTsd = sqlite3ThreadData();
  assert( pTsd );
#endif

  /* We used to test if malloc() had already failed before proceeding. 
  ** But the way this function is used in SQLite means that can never
  ** happen. Furthermore, if the malloc-failed flag is already set, 
  ** either the call to sqlite3StrDup() or sqlite3_malloc() below will
  ** fail shortly and SQLITE_NOMEM returned anyway.
  */
  *ppPager = 0;

  /* Allocate memory for the pager structure */
  pPager = sqlite3MallocZero(
    sizeof(*pPager) +           /* Pager structure */
    pVfs->szOsFile * 3 +        /* The db, journal and stmt journal files */ 
    pVfs->mxPathname * 3 + 30   /* zFilename, zDirectory, zJournal */
................................................................................
  if( !memDb ){
    setSectorSize(pPager);
  }
  /* pPager->pBusyHandler = 0; */
  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
  *ppPager = pPager;
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT





  pPager->pNext = pTsd->pPager;





  pTsd->pPager = pPager;


#endif
  return SQLITE_OK;
}

/*
** Set the busy handler function.
*/
................................................................................
** Set the page size.  Return the new size.  If the suggest new page
** size is inappropriate, then an alternative page size is selected
** and returned.
*/
int sqlite3PagerSetPagesize(Pager *pPager, int pageSize){
  assert( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE );
  if( !pPager->memDb && pPager->nRef==0 ){

    pager_reset(pPager);
    pPager->pageSize = pageSize;

    sqlite3_free(pPager->pTmpSpace);
    pPager->pTmpSpace = sqlite3_malloc(pageSize);
  }
  return pPager->pageSize;
}

/*
................................................................................
    return SQLITE_OK;
  }
  if( MEMDB ){
    pPager->dbSize = nPage;
    pager_truncate_cache(pPager);
    return SQLITE_OK;
  }

  rc = syncJournal(pPager);

  if( rc!=SQLITE_OK ){
    return rc;
  }

  /* Get an exclusive lock on the database before truncating. */

  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);

  if( rc!=SQLITE_OK ){
    return rc;
  }

  rc = pager_truncate(pPager, nPage);
  return rc;
}
................................................................................
** This function always succeeds. If a transaction is active an attempt
** is made to roll it back. If an error occurs during the rollback 
** a hot journal may be left in the filesystem but no error is returned
** to the caller.
*/
int sqlite3PagerClose(Pager *pPager){
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  /* A malloc() cannot fail in sqlite3ThreadData() as one or more calls to 
  ** malloc() must have already been made by this thread before it gets
  ** to this point. This means the ThreadData must have been allocated already
  ** so that ThreadData.nAlloc can be set.
  */

  ThreadData *pTsd = sqlite3ThreadData();


  assert( pPager );
  assert( pTsd && pTsd->nAlloc );




#endif

  disable_simulated_io_errors();
  pPager->errCode = 0;
  pPager->exclusiveMode = 0;
  pager_reset(pPager);
  pagerUnlockAndRollback(pPager);
................................................................................
  sqlite3OsClose(pPager->fd);
  /* Temp files are automatically deleted by the OS
  ** if( pPager->tempFile ){
  **   sqlite3OsDelete(pPager->zFilename);
  ** }
  */

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  /* Remove the pager from the linked list of pagers starting at 
  ** ThreadData.pPager if memory-management is enabled.
  */
  if( pPager==pTsd->pPager ){
    pTsd->pPager = pPager->pNext;
  }else{
    Pager *pTmp;
    for(pTmp = pTsd->pPager; pTmp->pNext!=pPager; pTmp=pTmp->pNext){}
    pTmp->pNext = pPager->pNext;
  }
#endif
  sqlite3_free(pPager->aHash);
  sqlite3_free(pPager->pTmpSpace);
  sqlite3_free(pPager);
  return SQLITE_OK;
}

#if !defined(NDEBUG) || defined(SQLITE_TEST)
................................................................................
#endif

/*
** Increment the reference count for a page.  The input pointer is
** a reference to the page data.
*/
int sqlite3PagerRef(DbPage *pPg){

  page_ref(pPg);

  return SQLITE_OK;
}

/*
** Sync the journal.  In other words, make sure all the pages that have
** been written to the journal have actually reached the surface of the
** disk.  It is not safe to modify the original database file until after
................................................................................
  unlinkPage(pPg);
  assert( pPg->pgno==0 );

  *ppPg = pPg;
  return SQLITE_OK;
}


/*
** This function is called to free superfluous dynamically allocated memory
** held by the pager system. Memory in use by any SQLite pager allocated
** by the current thread may be sqlite3_free()ed.
**
** nReq is the number of bytes of memory required. Once this much has
** been released, the function returns. A negative value for nReq means
** free as much memory as possible. The return value is the total number 
** of bytes of memory released.
*/
#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
int sqlite3PagerReleaseMemory(int nReq){
  const ThreadData *pTsdro = sqlite3ThreadDataReadOnly();
  int nReleased = 0;
  int i;

  /* If the the global mutex is held, this subroutine becomes a
  ** o-op; zero bytes of memory are freed.  This is because
  ** some of the code invoked by this function may also
  ** try to obtain the mutex, resulting in a deadlock.
  */
#if 0
  if( sqlite3OsInMutex(0) ){
    return 0;
  }
#endif

  /* Outermost loop runs for at most two iterations. First iteration we
  ** try to find memory that can be released without calling fsync(). Second
  ** iteration (which only runs if the first failed to free nReq bytes of
  ** memory) is permitted to call fsync(). This is of course much more 
  ** expensive.
  */
  for(i=0; i<=1; i++){

    /* Loop through all the SQLite pagers opened by the current thread. */
    Pager *pPager = pTsdro->pPager;
    for( ; pPager && (nReq<0 || nReleased<nReq); pPager=pPager->pNext){
      PgHdr *pPg;
      int rc;


      if( MEMDB ){
        continue;
      }



      /* For each pager, try to free as many pages as possible (without 
      ** calling fsync() if this is the first iteration of the outermost 
      ** loop).
      */
      while( SQLITE_OK==(rc = pager_recycle(pPager, i, &pPg)) && pPg) {
        /* We've found a page to free. At this point the page has been 
................................................................................
        assert( pPg );
        if( pPg==pPager->pAll ){
           pPager->pAll = pPg->pNextAll;
        }else{
          for( pTmp=pPager->pAll; pTmp->pNextAll!=pPg; pTmp=pTmp->pNextAll ){}
          pTmp->pNextAll = pPg->pNextAll;
        }
#if 0
        nReleased += sqliteAllocSize(pPg);
#else
        nReleased += (
            sizeof(*pPg) + pPager->pageSize
            + sizeof(u32) + pPager->nExtra
            + MEMDB*sizeof(PgHistory) 
        );
#endif
        IOTRACE(("PGFREE %p %d *\n", pPager, pPg->pgno));
        PAGER_INCR(sqlite3_pager_pgfree_count);
        sqlite3_free(pPg);
      }

      if( rc!=SQLITE_OK ){
        /* An error occured whilst writing to the database file or 
................................................................................
        );
        assert( pPager->state>=PAGER_RESERVED );
        pager_error(pPager, rc);
      }
    }
  }










  return nReleased;
}
#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT && !SQLITE_OMIT_DISKIO */

/*
** Read the content of page pPg out of the database file.
*/
static int readDbPage(Pager *pPager, PgHdr *pPg, Pgno pgno){
  int rc;
  i64 offset;
................................................................................
** of the page at this time, so do not do a disk read.  Just fill in the
** page content with zeros.  But mark the fact that we have not read the
** content by setting the PgHdr.needRead flag.  Later on, if 
** sqlite3PagerWrite() is called on this page or if this routine is
** called again with noContent==0, that means that the content is needed
** and the disk read should occur at that point.
*/
int sqlite3PagerAcquire(
  Pager *pPager,      /* The pager open on the database file */
  Pgno pgno,          /* Page number to fetch */
  DbPage **ppPage,    /* Write a pointer to the page here */
  int noContent       /* Do not bother reading content from disk if true */
){
  PgHdr *pPg;
  int rc;
................................................................................
      }
    }
    page_ref(pPg);
  }
  *ppPage = pPg;
  return SQLITE_OK;
}














/*
** Acquire a page if it is already in the in-memory cache.  Do
** not read the page from disk.  Return a pointer to the page,
** or 0 if the page is not in cache.
**
** See also sqlite3PagerGet().  The difference between this routine
** and sqlite3PagerGet() is that _get() will go to the disk and read
** in the page if the page is not already in cache.  This routine
** returns NULL if the page is not in cache or if a disk I/O error 
** has ever happened.
*/
DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
  PgHdr *pPg;

  assert( pPager!=0 );
  assert( pgno!=0 );


  if( pPager->state==PAGER_UNLOCK ){
    assert( !pPager->pAll || pPager->exclusiveMode );
    return 0;
  }
  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
    return 0;
  }

  pPg = pager_lookup(pPager, pgno);
  if( pPg==0 ) return 0;
  page_ref(pPg);


  return pPg;
}

/*
** Release a page.
**
** If the number of references to the page drop to zero, then the
................................................................................
** removed.
*/
int sqlite3PagerUnref(DbPage *pPg){

  /* Decrement the reference count for this page
  */
  assert( pPg->nRef>0 );

  pPg->nRef--;
  REFINFO(pPg);

  CHECK_PAGE(pPg);

  /* When the number of references to a page reach 0, call the
  ** destructor and add the page to the freelist.
................................................................................
    */
    pPager->nRef--;
    assert( pPager->nRef>=0 );
    if( pPager->nRef==0 && (!pPager->exclusiveMode || pPager->journalOff>0) ){
      pagerUnlockAndRollback(pPager);
    }
  }

  return SQLITE_OK;
}

/*
** Create a journal file for pPager.  There should already be a RESERVED
** or EXCLUSIVE lock on the database file when this routine is called.
**
................................................................................
** If exFlag is true, go ahead and get an EXCLUSIVE lock on the file
** immediately instead of waiting until we try to flush the cache.  The
** exFlag is ignored if a transaction is already active.
*/
int sqlite3PagerBegin(DbPage *pPg, int exFlag){
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;

  assert( pPg->nRef>0 );
  assert( pPager->state!=PAGER_UNLOCK );
  if( pPager->state==PAGER_SHARED ){
    assert( pPager->aInJournal==0 );
    if( MEMDB ){
      pPager->state = PAGER_EXCLUSIVE;
      pPager->origDbSize = pPager->dbSize;
................................................................................
      if( rc==SQLITE_OK ){
        pPager->state = PAGER_RESERVED;
        if( exFlag ){
          rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
        }
      }
      if( rc!=SQLITE_OK ){

        return rc;
      }
      pPager->dirtyCache = 0;
      PAGERTRACE2("TRANSACTION %d\n", PAGERID(pPager));
      if( pPager->useJournal && !pPager->tempFile ){
        rc = pager_open_journal(pPager);
      }
................................................................................
      rc = SQLITE_NOMEM;
    }else{
      pPager->origDbSize = pPager->dbSize;
      rc = writeJournalHdr(pPager);
    }
  }
  assert( !pPager->journalOpen || pPager->journalOff>0 || rc!=SQLITE_OK );

  return rc;
}

/*
** Make a page dirty.  Set its dirty flag and add it to the dirty
** page list.
*/
................................................................................
int sqlite3PagerWrite(DbPage *pDbPage){
  int rc = SQLITE_OK;

  PgHdr *pPg = pDbPage;
  Pager *pPager = pPg->pPager;
  Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);


  if( !MEMDB && nPagePerSector>1 ){
    Pgno nPageCount;          /* Total number of pages in database file */
    Pgno pg1;                 /* First page of the sector pPg is located on. */
    int nPage;                /* Number of pages starting at pg1 to journal */
    int ii;

    /* Set the doNotSync flag to 1. This is because we cannot allow a journal
................................................................................
    }

    assert( pPager->doNotSync==1 );
    pPager->doNotSync = 0;
  }else{
    rc = pager_write(pDbPage);
  }

  return rc;
}

/*
** Return TRUE if the page given in the argument was previously passed
** to sqlite3PagerWrite().  In other words, return TRUE if it is ok
** to change the content of the page.
................................................................................
** Replace the content of a single page with the information in the third
** argument.
*/
int sqlite3PagerOverwrite(Pager *pPager, Pgno pgno, void *pData){
  PgHdr *pPg;
  int rc;


  rc = sqlite3PagerGet(pPager, pgno, &pPg);
  if( rc==SQLITE_OK ){
    rc = sqlite3PagerWrite(pPg);
    if( rc==SQLITE_OK ){
      memcpy(sqlite3PagerGetData(pPg), pData, pPager->pageSize);
    }
    sqlite3PagerUnref(pPg);
  }

  return rc;
}
#endif

/*
** A call to this routine tells the pager that it is not necessary to
** write the information on page pPg back to the disk, even though
................................................................................
** rolled back in spite of the sqlite3PagerDontRollback() call.
*/
void sqlite3PagerDontWrite(DbPage *pDbPage){
  PgHdr *pPg = pDbPage;
  Pager *pPager = pPg->pPager;

  if( MEMDB ) return;

  pPg->alwaysRollback = 1;
  if( pPg->dirty && !pPager->stmtInUse ){
    assert( pPager->state>=PAGER_SHARED );
    if( pPager->dbSize==(int)pPg->pgno && pPager->origDbSize<pPager->dbSize ){
      /* If this pages is the last page in the file and the file has grown
      ** during the current transaction, then do NOT mark the page as clean.
      ** When the database file grows, we must make sure that the last page
................................................................................
      IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
      makeClean(pPg);
#ifdef SQLITE_CHECK_PAGES
      pPg->pageHash = pager_pagehash(pPg);
#endif
    }
  }

}

/*
** A call to this routine tells the pager that if a rollback occurs,
** it is not necessary to restore the data on the given page.  This
** means that the pager does not have to record the given page in the
** rollback journal.
................................................................................
** the PgHdr.needRead flag is set) then this routine acts as a promise
** that we will never need to read the page content in the future.
** so the needRead flag can be cleared at this point.
*/
void sqlite3PagerDontRollback(DbPage *pPg){
  Pager *pPager = pPg->pPager;


  assert( pPager->state>=PAGER_RESERVED );
  if( pPager->journalOpen==0 ) return;
  if( pPg->alwaysRollback || pPager->alwaysRollback || MEMDB ) return;
  if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
    assert( pPager->aInJournal!=0 );
    pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
    pPg->inJournal = 1;
................................................................................
   && !pageInStatement(pPg) 
   && (int)pPg->pgno<=pPager->stmtSize 
  ){
    assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
    assert( pPager->aInStmt!=0 );
    pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
  }

}


/*
** This routine is called to increment the database file change-counter,
** stored at byte 24 of the pager file.
*/
................................................................................
** nTrunc pages (this is used by auto-vacuum databases).
*/
int sqlite3PagerCommitPhaseOne(Pager *pPager, const char *zMaster, Pgno nTrunc){
  int rc = SQLITE_OK;

  PAGERTRACE4("DATABASE SYNC: File=%s zMaster=%s nTrunc=%d\n", 
      pPager->zFilename, zMaster, nTrunc);


  /* If this is an in-memory db, or no pages have been written to, or this
  ** function has already been called, it is a no-op.
  */
  if( pPager->state!=PAGER_SYNCED && !MEMDB && pPager->dirtyCache ){
    PgHdr *pPg;
    assert( pPager->journalOpen );
................................................................................
    /* pager_incr_changecounter() may attempt to obtain an exclusive
     * lock to spill the cache and return IOERR_BLOCKED. But since 
     * there is no chance the cache is inconsistent, it's
     * better to return SQLITE_BUSY.
     */
    rc = SQLITE_BUSY;
  }

  return rc;
}


/*
** Commit all changes to the database and release the write lock.
**
................................................................................

  if( pPager->errCode ){
    return pPager->errCode;
  }
  if( pPager->state<PAGER_RESERVED ){
    return SQLITE_ERROR;
  }

  PAGERTRACE2("COMMIT %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPg = pager_get_all_dirty_pages(pPager);
    while( pPg ){
      PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
      clearHistory(pHist);
      pPg->dirty = 0;
................................................................................
    pPager->pStmt = 0;
    pPager->state = PAGER_SHARED;
    return SQLITE_OK;
  }
  assert( pPager->journalOpen || !pPager->dirtyCache );
  assert( pPager->state==PAGER_SYNCED || !pPager->dirtyCache );
  rc = pager_end_transaction(pPager);
  return pager_error(pPager, rc);


}

/*
** Rollback all changes.  The database falls back to PAGER_SHARED mode.
** All in-memory cache pages revert to their original data contents.
** The journal is deleted.
**
................................................................................
    pPager->dbSize = pPager->origDbSize;
    pager_truncate_cache(pPager);
    pPager->stmtInUse = 0;
    pPager->state = PAGER_SHARED;
    return SQLITE_OK;
  }


  if( !pPager->dirtyCache || !pPager->journalOpen ){
    rc = pager_end_transaction(pPager);

    return rc;
  }

  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
    if( pPager->state>=PAGER_EXCLUSIVE ){
      pager_playback(pPager, 0);
    }

    return pPager->errCode;
  }
  if( pPager->state==PAGER_RESERVED ){
    int rc2;
    rc = pager_playback(pPager, 0);
    rc2 = pager_end_transaction(pPager);
    if( rc==SQLITE_OK ){
................................................................................
  /* pager_reset(pPager); */
  pPager->dbSize = -1;

  /* If an error occurs during a ROLLBACK, we can no longer trust the pager
  ** cache. So call pager_error() on the way out to make any error 
  ** persistent.
  */
  return pager_error(pPager, rc);


}

/*
** Return TRUE if the database file is opened read-only.  Return FALSE
** if the database is (in theory) writable.
*/
int sqlite3PagerIsreadonly(Pager *pPager){
................................................................................
/*
** Set the statement rollback point.
**
** This routine should be called with the transaction journal already
** open.  A new statement journal is created that can be used to rollback
** changes of a single SQL command within a larger transaction.
*/
int sqlite3PagerStmtBegin(Pager *pPager){
  int rc;
  assert( !pPager->stmtInUse );
  assert( pPager->state>=PAGER_SHARED );
  assert( pPager->dbSize>=0 );
  PAGERTRACE2("STMT-BEGIN %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPager->stmtInUse = 1;
................................................................................
stmt_begin_failed:
  if( pPager->aInStmt ){
    sqlite3_free(pPager->aInStmt);
    pPager->aInStmt = 0;
  }
  return rc;
}








/*
** Commit a statement.
*/
int sqlite3PagerStmtCommit(Pager *pPager){

  if( pPager->stmtInUse ){
    PgHdr *pPg, *pNext;
    PAGERTRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
    if( !MEMDB ){
      /* sqlite3OsTruncate(pPager->stfd, 0); */
      sqlite3_free( pPager->aInStmt );
      pPager->aInStmt = 0;
................................................................................
      }
    }
    pPager->stmtNRec = 0;
    pPager->stmtInUse = 0;
    pPager->pStmt = 0;
  }
  pPager->stmtAutoopen = 0;

  return SQLITE_OK;
}

/*
** Rollback a statement.
*/
int sqlite3PagerStmtRollback(Pager *pPager){
  int rc;

  if( pPager->stmtInUse ){
    PAGERTRACE2("STMT-ROLLBACK %d\n", PAGERID(pPager));
    if( MEMDB ){
      PgHdr *pPg;
      PgHistory *pHist;
      for(pPg=pPager->pStmt; pPg; pPg=pHist->pNextStmt){
        pHist = PGHDR_TO_HIST(pPg, pPager);
................................................................................
      rc = pager_stmt_playback(pPager);
    }
    sqlite3PagerStmtCommit(pPager);
  }else{
    rc = SQLITE_OK;
  }
  pPager->stmtAutoopen = 0;

  return rc;
}

/*
** Return the full pathname of the database file.
*/
const char *sqlite3PagerFilename(Pager *pPager){
................................................................................
** transaction is active).
*/
int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno){
  PgHdr *pPgOld;  /* The page being overwritten. */
  int h;
  Pgno needSyncPgno = 0;


  assert( pPg->nRef>0 );

  PAGERTRACE5("MOVE %d page %d (needSync=%d) moves to %d\n", 
      PAGERID(pPager), pPg->pgno, pPg->needSync, pgno);
  IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))

  pager_get_content(pPg);
................................................................................
    pPager->needSync = 1;
    pPgHdr->needSync = 1;
    pPgHdr->inJournal = 1;
    makeDirty(pPgHdr);
    sqlite3PagerUnref(pPgHdr);
  }


  return SQLITE_OK;
}
#endif

/*
** Return a pointer to the data for the specified page.
*/

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.365 2007/08/22 00:39:20 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*
................................................................................
#ifdef SQLITE_HAS_CODEC
  void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
  void *pCodecArg;            /* First argument to xCodec() */
#endif
  int nHash;                  /* Size of the pager hash table */
  PgHdr **aHash;              /* Hash table to map page number to PgHdr */
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  Pager *pNext;               /* Doubly linked list of pagers on which */
  Pager *pPrev;               /* sqlite3_release_memory() will work */
  int iInUseMM;               /* Non-zero if unavailable to MM */
  int iInUseDB;               /* Non-zero if in sqlite3_release_memory() */
#endif
  char *pTmpSpace;            /* Pager.pageSize bytes of space for tmp use */
  char dbFileVers[16];        /* Changes whenever database file changes */
};

/*
** The following global variables hold counters used for
................................................................................
int sqlite3_pager_writej_count = 0;    /* Number of pages written to journal */
int sqlite3_pager_pgfree_count = 0;    /* Number of cache pages freed */
# define PAGER_INCR(v)  v++
#else
# define PAGER_INCR(v)
#endif

/*
** The following variable points to the head of a double-linked list
** of all pagers that are eligible for page stealing by the
** sqlite3_release_memory() interface.  Access to this list is
** protected by the SQLITE_MUTEX_STATIC_MEM2 mutex.
*/
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
static Pager *sqlite3PagerList = 0;
#endif


/*
** Journal files begin with the following magic string.  The data
** was obtained from /dev/random.  It is used only as a sanity check.
**
** Since version 2.8.0, the journal format contains additional sanity
................................................................................
#define PAGER_MJ_PGNO(x) ((PENDING_BYTE/((x)->pageSize))+1)

/*
** The maximum legal page number is (2^31 - 1).
*/
#define PAGER_MAX_PGNO 2147483647

/*
** The pagerEnter() and pagerLeave() routines acquire and release
** a mutex on each pager.  The mutex is recursive.
**
** This is a special-purpose mutex.  It only provides mutual exclusion
** between the Btree and the Memory Management sqlite3_release_memory()
** function.  It does not prevent, for example, two Btrees from accessing
** the same pager at the same time.  Other general-purpose mutexes in
** the btree layer handle that chore.
*/
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  static void pagerEnter(Pager *p){
    p->iInUseDB++;
    if( p->iInUseMM && p->iInUseDB==1 ){
      sqlite3_mutex *mutex;
      mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
      p->iInUseDB = 0;
      sqlite3_mutex_enter(mutex);
      p->iInUseDB = 1;
      sqlite3_mutex_leave(mutex);
    }
    assert( p->iInUseMM==0 );
  }
  static void pagerLeave(Pager *p){
    p->iInUseDB--;
    assert( p->iInUseDB>=0 );
  }
#else
# define pagerEnter(X)
# define pagerLeave(X)
#endif

/*
** Enable reference count tracking (for debugging) here:
*/
#ifdef SQLITE_DEBUG
  int pager3_refinfo_enable = 0;
  static void pager_refinfo(PgHdr *p){
    static int cnt = 0;
................................................................................
** automatically when it is closed.
**
** If zFilename is ":memory:" then all information is held in cache.
** It is never written to disk.  This can be used to implement an
** in-memory database.
*/
int sqlite3PagerOpen(
  sqlite3_vfs *pVfs,       /* The virtual file system to use */
  Pager **ppPager,         /* Return the Pager structure here */
  const char *zFilename,   /* Name of the database file to open */
  int nExtra,              /* Extra bytes append to each in-memory page */
  int flags                /* flags controlling this file */
){
  u8 *pPtr;
  Pager *pPager = 0;
................................................................................
  int i;
  int tempFile = 0;
  int memDb = 0;
  int readOnly = 0;
  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
  int noReadlock = (flags & PAGER_NO_READLOCK)!=0;

  /* The default return is a NULL pointer */

















  *ppPager = 0;

  /* Allocate memory for the pager structure */
  pPager = sqlite3MallocZero(
    sizeof(*pPager) +           /* Pager structure */
    pVfs->szOsFile * 3 +        /* The db, journal and stmt journal files */ 
    pVfs->mxPathname * 3 + 30   /* zFilename, zDirectory, zJournal */
................................................................................
  if( !memDb ){
    setSectorSize(pPager);
  }
  /* pPager->pBusyHandler = 0; */
  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
  *ppPager = pPager;
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  pPager->iInUseMM = 0;
  pPager->iInUseDB = 0;
  if( !memDb ){
    sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
    sqlite3_mutex_enter(mutex);
    pPager->pNext = sqlite3PagerList;
    if( sqlite3PagerList ){
      assert( sqlite3PagerList->pPrev==0 );
      sqlite3PagerList->pPrev = pPager;
    }
    pPager->pPrev = 0;
    sqlite3PagerList = pPager;
    sqlite3_mutex_leave(mutex);
  }
#endif
  return SQLITE_OK;
}

/*
** Set the busy handler function.
*/
................................................................................
** Set the page size.  Return the new size.  If the suggest new page
** size is inappropriate, then an alternative page size is selected
** and returned.
*/
int sqlite3PagerSetPagesize(Pager *pPager, int pageSize){
  assert( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE );
  if( !pPager->memDb && pPager->nRef==0 ){
    pagerEnter(pPager);
    pager_reset(pPager);
    pPager->pageSize = pageSize;
    pagerLeave(pPager);
    sqlite3_free(pPager->pTmpSpace);
    pPager->pTmpSpace = sqlite3_malloc(pageSize);
  }
  return pPager->pageSize;
}

/*
................................................................................
    return SQLITE_OK;
  }
  if( MEMDB ){
    pPager->dbSize = nPage;
    pager_truncate_cache(pPager);
    return SQLITE_OK;
  }
  pagerEnter(pPager);
  rc = syncJournal(pPager);
  pagerLeave(pPager);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  /* Get an exclusive lock on the database before truncating. */
  pagerEnter(pPager);
  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
  pagerLeave(pPager);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  rc = pager_truncate(pPager, nPage);
  return rc;
}
................................................................................
** This function always succeeds. If a transaction is active an attempt
** is made to roll it back. If an error occurs during the rollback 
** a hot journal may be left in the filesystem but no error is returned
** to the caller.
*/
int sqlite3PagerClose(Pager *pPager){
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  if( !MEMDB ){
    sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
    sqlite3_mutex_enter(mutex);
    if( pPager->pPrev ){

      pPager->pPrev->pNext = pPager->pNext;
    }else{
      sqlite3PagerList = pPager->pNext;
    }
    if( pPager->pNext ){

      pPager->pNext->pPrev = pPager->pPrev;
    }
    sqlite3_mutex_leave(mutex);
  }
#endif

  disable_simulated_io_errors();
  pPager->errCode = 0;
  pPager->exclusiveMode = 0;
  pager_reset(pPager);
  pagerUnlockAndRollback(pPager);
................................................................................
  sqlite3OsClose(pPager->fd);
  /* Temp files are automatically deleted by the OS
  ** if( pPager->tempFile ){
  **   sqlite3OsDelete(pPager->zFilename);
  ** }
  */













  sqlite3_free(pPager->aHash);
  sqlite3_free(pPager->pTmpSpace);
  sqlite3_free(pPager);
  return SQLITE_OK;
}

#if !defined(NDEBUG) || defined(SQLITE_TEST)
................................................................................
#endif

/*
** Increment the reference count for a page.  The input pointer is
** a reference to the page data.
*/
int sqlite3PagerRef(DbPage *pPg){
  pagerEnter(pPg->pPager);
  page_ref(pPg);
  pagerLeave(pPg->pPager);
  return SQLITE_OK;
}

/*
** Sync the journal.  In other words, make sure all the pages that have
** been written to the journal have actually reached the surface of the
** disk.  It is not safe to modify the original database file until after
................................................................................
  unlinkPage(pPg);
  assert( pPg->pgno==0 );

  *ppPg = pPg;
  return SQLITE_OK;
}

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/*
** This function is called to free superfluous dynamically allocated memory
** held by the pager system. Memory in use by any SQLite pager allocated
** by the current thread may be sqlite3_free()ed.
**
** nReq is the number of bytes of memory required. Once this much has
** been released, the function returns. The return value is the total number 
** of bytes of memory released.
*/
int sqlite3PagerReleaseMemory(int nReq){
  int nReleased = 0;          /* Bytes of memory released so far */
  sqlite3_mutex *mutex;       /* The MEM2 mutex */
  Pager *pPager;              /* For looping over pagers */
  int i;                      /* Passes over pagers */

  /* Acquire the memory-management mutex
  */
  mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
  sqlite3_mutex_enter(mutex);

  /* Signal all database connections that memory management wants
  ** to have access to the pagers.
  */
  for(pPager=sqlite3PagerList; pPager; pPager=pPager->pNext){
     pPager->iInUseMM = 1;
  }

  /* Outermost loop runs for at most two iterations. First iteration we
  ** try to find memory that can be released without calling fsync(). Second
  ** iteration (which only runs if the first failed to free nReq bytes of
  ** memory) is permitted to call fsync(). This is of course much more 
  ** expensive.
  */
  for(i=0; i<=1; i++){

    /* Loop through all the SQLite pagers opened by the current thread. */
    Pager *pPager = sqlite3PagerList;
    for( ; pPager && (nReq<0 || nReleased<nReq); pPager=pPager->pNext){
      PgHdr *pPg;
      int rc;

      /* In-memory databases should not appear on the pager list */
      assert( !MEMDB );


      /* Skip pagers that are currently in use by the b-tree layer */
      if( pPager->iInUseDB ) continue;

      /* For each pager, try to free as many pages as possible (without 
      ** calling fsync() if this is the first iteration of the outermost 
      ** loop).
      */
      while( SQLITE_OK==(rc = pager_recycle(pPager, i, &pPg)) && pPg) {
        /* We've found a page to free. At this point the page has been 
................................................................................
        assert( pPg );
        if( pPg==pPager->pAll ){
           pPager->pAll = pPg->pNextAll;
        }else{
          for( pTmp=pPager->pAll; pTmp->pNextAll!=pPg; pTmp=pTmp->pNextAll ){}
          pTmp->pNextAll = pPg->pNextAll;
        }



        nReleased += (
            sizeof(*pPg) + pPager->pageSize
            + sizeof(u32) + pPager->nExtra
            + MEMDB*sizeof(PgHistory) 
        );

        IOTRACE(("PGFREE %p %d *\n", pPager, pPg->pgno));
        PAGER_INCR(sqlite3_pager_pgfree_count);
        sqlite3_free(pPg);
      }

      if( rc!=SQLITE_OK ){
        /* An error occured whilst writing to the database file or 
................................................................................
        );
        assert( pPager->state>=PAGER_RESERVED );
        pager_error(pPager, rc);
      }
    }
  }

  /* Clear the memory management flags and release the mutex
  */
  for(pPager=sqlite3PagerList; pPager; pPager=pPager->pNext){
     pPager->iInUseMM = 0;
  }
  sqlite3_mutex_leave(mutex);

  /* Return the number of bytes released
  */
  return nReleased;
}
#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */

/*
** Read the content of page pPg out of the database file.
*/
static int readDbPage(Pager *pPager, PgHdr *pPg, Pgno pgno){
  int rc;
  i64 offset;
................................................................................
** of the page at this time, so do not do a disk read.  Just fill in the
** page content with zeros.  But mark the fact that we have not read the
** content by setting the PgHdr.needRead flag.  Later on, if 
** sqlite3PagerWrite() is called on this page or if this routine is
** called again with noContent==0, that means that the content is needed
** and the disk read should occur at that point.
*/
static int pagerAcquire(
  Pager *pPager,      /* The pager open on the database file */
  Pgno pgno,          /* Page number to fetch */
  DbPage **ppPage,    /* Write a pointer to the page here */
  int noContent       /* Do not bother reading content from disk if true */
){
  PgHdr *pPg;
  int rc;
................................................................................
      }
    }
    page_ref(pPg);
  }
  *ppPage = pPg;
  return SQLITE_OK;
}
int sqlite3PagerAcquire(
  Pager *pPager,      /* The pager open on the database file */
  Pgno pgno,          /* Page number to fetch */
  DbPage **ppPage,    /* Write a pointer to the page here */
  int noContent       /* Do not bother reading content from disk if true */
){
  int rc;
  pagerEnter(pPager);
  rc = pagerAcquire(pPager, pgno, ppPage, noContent);
  pagerLeave(pPager);
  return rc;
}


/*
** Acquire a page if it is already in the in-memory cache.  Do
** not read the page from disk.  Return a pointer to the page,
** or 0 if the page is not in cache.
**
** See also sqlite3PagerGet().  The difference between this routine
** and sqlite3PagerGet() is that _get() will go to the disk and read
** in the page if the page is not already in cache.  This routine
** returns NULL if the page is not in cache or if a disk I/O error 
** has ever happened.
*/
DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
  PgHdr *pPg = 0;

  assert( pPager!=0 );
  assert( pgno!=0 );

  pagerEnter(pPager);
  if( pPager->state==PAGER_UNLOCK ){
    assert( !pPager->pAll || pPager->exclusiveMode );


  }else if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){


    /* Do nothing */
  }else if( (pPg = pager_lookup(pPager, pgno))!=0 ){

    page_ref(pPg);
  }
  pagerLeave(pPager);
  return pPg;
}

/*
** Release a page.
**
** If the number of references to the page drop to zero, then the
................................................................................
** removed.
*/
int sqlite3PagerUnref(DbPage *pPg){

  /* Decrement the reference count for this page
  */
  assert( pPg->nRef>0 );
  pagerEnter(pPg->pPager);
  pPg->nRef--;
  REFINFO(pPg);

  CHECK_PAGE(pPg);

  /* When the number of references to a page reach 0, call the
  ** destructor and add the page to the freelist.
................................................................................
    */
    pPager->nRef--;
    assert( pPager->nRef>=0 );
    if( pPager->nRef==0 && (!pPager->exclusiveMode || pPager->journalOff>0) ){
      pagerUnlockAndRollback(pPager);
    }
  }
  pagerLeave(pPg->pPager);
  return SQLITE_OK;
}

/*
** Create a journal file for pPager.  There should already be a RESERVED
** or EXCLUSIVE lock on the database file when this routine is called.
**
................................................................................
** If exFlag is true, go ahead and get an EXCLUSIVE lock on the file
** immediately instead of waiting until we try to flush the cache.  The
** exFlag is ignored if a transaction is already active.
*/
int sqlite3PagerBegin(DbPage *pPg, int exFlag){
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;
  pagerEnter(pPager);
  assert( pPg->nRef>0 );
  assert( pPager->state!=PAGER_UNLOCK );
  if( pPager->state==PAGER_SHARED ){
    assert( pPager->aInJournal==0 );
    if( MEMDB ){
      pPager->state = PAGER_EXCLUSIVE;
      pPager->origDbSize = pPager->dbSize;
................................................................................
      if( rc==SQLITE_OK ){
        pPager->state = PAGER_RESERVED;
        if( exFlag ){
          rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
        }
      }
      if( rc!=SQLITE_OK ){
        pagerLeave(pPager);
        return rc;
      }
      pPager->dirtyCache = 0;
      PAGERTRACE2("TRANSACTION %d\n", PAGERID(pPager));
      if( pPager->useJournal && !pPager->tempFile ){
        rc = pager_open_journal(pPager);
      }
................................................................................
      rc = SQLITE_NOMEM;
    }else{
      pPager->origDbSize = pPager->dbSize;
      rc = writeJournalHdr(pPager);
    }
  }
  assert( !pPager->journalOpen || pPager->journalOff>0 || rc!=SQLITE_OK );
  pagerLeave(pPager);
  return rc;
}

/*
** Make a page dirty.  Set its dirty flag and add it to the dirty
** page list.
*/
................................................................................
int sqlite3PagerWrite(DbPage *pDbPage){
  int rc = SQLITE_OK;

  PgHdr *pPg = pDbPage;
  Pager *pPager = pPg->pPager;
  Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);

  pagerEnter(pPager);
  if( !MEMDB && nPagePerSector>1 ){
    Pgno nPageCount;          /* Total number of pages in database file */
    Pgno pg1;                 /* First page of the sector pPg is located on. */
    int nPage;                /* Number of pages starting at pg1 to journal */
    int ii;

    /* Set the doNotSync flag to 1. This is because we cannot allow a journal
................................................................................
    }

    assert( pPager->doNotSync==1 );
    pPager->doNotSync = 0;
  }else{
    rc = pager_write(pDbPage);
  }
  pagerLeave(pPager);
  return rc;
}

/*
** Return TRUE if the page given in the argument was previously passed
** to sqlite3PagerWrite().  In other words, return TRUE if it is ok
** to change the content of the page.
................................................................................
** Replace the content of a single page with the information in the third
** argument.
*/
int sqlite3PagerOverwrite(Pager *pPager, Pgno pgno, void *pData){
  PgHdr *pPg;
  int rc;

  pagerEnter(pPager);
  rc = sqlite3PagerGet(pPager, pgno, &pPg);
  if( rc==SQLITE_OK ){
    rc = sqlite3PagerWrite(pPg);
    if( rc==SQLITE_OK ){
      memcpy(sqlite3PagerGetData(pPg), pData, pPager->pageSize);
    }
    sqlite3PagerUnref(pPg);
  }
  pagerLeave(pPager);
  return rc;
}
#endif

/*
** A call to this routine tells the pager that it is not necessary to
** write the information on page pPg back to the disk, even though
................................................................................
** rolled back in spite of the sqlite3PagerDontRollback() call.
*/
void sqlite3PagerDontWrite(DbPage *pDbPage){
  PgHdr *pPg = pDbPage;
  Pager *pPager = pPg->pPager;

  if( MEMDB ) return;
  pagerEnter(pPager);
  pPg->alwaysRollback = 1;
  if( pPg->dirty && !pPager->stmtInUse ){
    assert( pPager->state>=PAGER_SHARED );
    if( pPager->dbSize==(int)pPg->pgno && pPager->origDbSize<pPager->dbSize ){
      /* If this pages is the last page in the file and the file has grown
      ** during the current transaction, then do NOT mark the page as clean.
      ** When the database file grows, we must make sure that the last page
................................................................................
      IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
      makeClean(pPg);
#ifdef SQLITE_CHECK_PAGES
      pPg->pageHash = pager_pagehash(pPg);
#endif
    }
  }
  pagerLeave(pPager);
}

/*
** A call to this routine tells the pager that if a rollback occurs,
** it is not necessary to restore the data on the given page.  This
** means that the pager does not have to record the given page in the
** rollback journal.
................................................................................
** the PgHdr.needRead flag is set) then this routine acts as a promise
** that we will never need to read the page content in the future.
** so the needRead flag can be cleared at this point.
*/
void sqlite3PagerDontRollback(DbPage *pPg){
  Pager *pPager = pPg->pPager;

  pagerEnter(pPager);
  assert( pPager->state>=PAGER_RESERVED );
  if( pPager->journalOpen==0 ) return;
  if( pPg->alwaysRollback || pPager->alwaysRollback || MEMDB ) return;
  if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
    assert( pPager->aInJournal!=0 );
    pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
    pPg->inJournal = 1;
................................................................................
   && !pageInStatement(pPg) 
   && (int)pPg->pgno<=pPager->stmtSize 
  ){
    assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
    assert( pPager->aInStmt!=0 );
    pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
  }
  pagerLeave(pPager);
}


/*
** This routine is called to increment the database file change-counter,
** stored at byte 24 of the pager file.
*/
................................................................................
** nTrunc pages (this is used by auto-vacuum databases).
*/
int sqlite3PagerCommitPhaseOne(Pager *pPager, const char *zMaster, Pgno nTrunc){
  int rc = SQLITE_OK;

  PAGERTRACE4("DATABASE SYNC: File=%s zMaster=%s nTrunc=%d\n", 
      pPager->zFilename, zMaster, nTrunc);
  pagerEnter(pPager);

  /* If this is an in-memory db, or no pages have been written to, or this
  ** function has already been called, it is a no-op.
  */
  if( pPager->state!=PAGER_SYNCED && !MEMDB && pPager->dirtyCache ){
    PgHdr *pPg;
    assert( pPager->journalOpen );
................................................................................
    /* pager_incr_changecounter() may attempt to obtain an exclusive
     * lock to spill the cache and return IOERR_BLOCKED. But since 
     * there is no chance the cache is inconsistent, it's
     * better to return SQLITE_BUSY.
     */
    rc = SQLITE_BUSY;
  }
  pagerLeave(pPager);
  return rc;
}


/*
** Commit all changes to the database and release the write lock.
**
................................................................................

  if( pPager->errCode ){
    return pPager->errCode;
  }
  if( pPager->state<PAGER_RESERVED ){
    return SQLITE_ERROR;
  }
  pagerEnter(pPager);
  PAGERTRACE2("COMMIT %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPg = pager_get_all_dirty_pages(pPager);
    while( pPg ){
      PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
      clearHistory(pHist);
      pPg->dirty = 0;
................................................................................
    pPager->pStmt = 0;
    pPager->state = PAGER_SHARED;
    return SQLITE_OK;
  }
  assert( pPager->journalOpen || !pPager->dirtyCache );
  assert( pPager->state==PAGER_SYNCED || !pPager->dirtyCache );
  rc = pager_end_transaction(pPager);
  rc = pager_error(pPager, rc);
  pagerLeave(pPager);
  return rc;
}

/*
** Rollback all changes.  The database falls back to PAGER_SHARED mode.
** All in-memory cache pages revert to their original data contents.
** The journal is deleted.
**
................................................................................
    pPager->dbSize = pPager->origDbSize;
    pager_truncate_cache(pPager);
    pPager->stmtInUse = 0;
    pPager->state = PAGER_SHARED;
    return SQLITE_OK;
  }

  pagerEnter(pPager);
  if( !pPager->dirtyCache || !pPager->journalOpen ){
    rc = pager_end_transaction(pPager);
    pagerLeave(pPager);
    return rc;
  }

  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
    if( pPager->state>=PAGER_EXCLUSIVE ){
      pager_playback(pPager, 0);
    }
    pagerLeave(pPager);
    return pPager->errCode;
  }
  if( pPager->state==PAGER_RESERVED ){
    int rc2;
    rc = pager_playback(pPager, 0);
    rc2 = pager_end_transaction(pPager);
    if( rc==SQLITE_OK ){
................................................................................
  /* pager_reset(pPager); */
  pPager->dbSize = -1;

  /* If an error occurs during a ROLLBACK, we can no longer trust the pager
  ** cache. So call pager_error() on the way out to make any error 
  ** persistent.
  */
  rc = pager_error(pPager, rc);
  pagerLeave(pPager);
  return rc;
}

/*
** Return TRUE if the database file is opened read-only.  Return FALSE
** if the database is (in theory) writable.
*/
int sqlite3PagerIsreadonly(Pager *pPager){
................................................................................
/*
** Set the statement rollback point.
**
** This routine should be called with the transaction journal already
** open.  A new statement journal is created that can be used to rollback
** changes of a single SQL command within a larger transaction.
*/
static int pagerStmtBegin(Pager *pPager){
  int rc;
  assert( !pPager->stmtInUse );
  assert( pPager->state>=PAGER_SHARED );
  assert( pPager->dbSize>=0 );
  PAGERTRACE2("STMT-BEGIN %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPager->stmtInUse = 1;
................................................................................
stmt_begin_failed:
  if( pPager->aInStmt ){
    sqlite3_free(pPager->aInStmt);
    pPager->aInStmt = 0;
  }
  return rc;
}
int sqlite3PagerStmtBegin(Pager *pPager){
  int rc;
  pagerEnter(pPager);
  rc = pagerStmtBegin(pPager);
  pagerLeave(pPager);
  return rc;
}

/*
** Commit a statement.
*/
int sqlite3PagerStmtCommit(Pager *pPager){
  pagerEnter(pPager);
  if( pPager->stmtInUse ){
    PgHdr *pPg, *pNext;
    PAGERTRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
    if( !MEMDB ){
      /* sqlite3OsTruncate(pPager->stfd, 0); */
      sqlite3_free( pPager->aInStmt );
      pPager->aInStmt = 0;
................................................................................
      }
    }
    pPager->stmtNRec = 0;
    pPager->stmtInUse = 0;
    pPager->pStmt = 0;
  }
  pPager->stmtAutoopen = 0;
  pagerLeave(pPager);
  return SQLITE_OK;
}

/*
** Rollback a statement.
*/
int sqlite3PagerStmtRollback(Pager *pPager){
  int rc;
  pagerEnter(pPager);
  if( pPager->stmtInUse ){
    PAGERTRACE2("STMT-ROLLBACK %d\n", PAGERID(pPager));
    if( MEMDB ){
      PgHdr *pPg;
      PgHistory *pHist;
      for(pPg=pPager->pStmt; pPg; pPg=pHist->pNextStmt){
        pHist = PGHDR_TO_HIST(pPg, pPager);
................................................................................
      rc = pager_stmt_playback(pPager);
    }
    sqlite3PagerStmtCommit(pPager);
  }else{
    rc = SQLITE_OK;
  }
  pPager->stmtAutoopen = 0;
  pagerLeave(pPager);
  return rc;
}

/*
** Return the full pathname of the database file.
*/
const char *sqlite3PagerFilename(Pager *pPager){
................................................................................
** transaction is active).
*/
int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno){
  PgHdr *pPgOld;  /* The page being overwritten. */
  int h;
  Pgno needSyncPgno = 0;

  pagerEnter(pPager);
  assert( pPg->nRef>0 );

  PAGERTRACE5("MOVE %d page %d (needSync=%d) moves to %d\n", 
      PAGERID(pPager), pPg->pgno, pPg->needSync, pgno);
  IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))

  pager_get_content(pPg);
................................................................................
    pPager->needSync = 1;
    pPgHdr->needSync = 1;
    pPgHdr->inJournal = 1;
    makeDirty(pPgHdr);
    sqlite3PagerUnref(pPgHdr);
  }

  pagerLeave(pPager);
  return SQLITE_OK;
}
#endif

/*
** Return a pointer to the data for the specified page.
*/

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the implementation of the sqlite3_prepare()
** interface, and routines that contribute to loading the database schema
** from disk.
**
** $Id: prepare.c,v 1.56 2007/08/21 19:33:56 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates
** that the database is corrupt.
................................................................................
  const char **pzTail       /* OUT: End of parsed string */
){
  Parse sParse;
  char *zErrMsg = 0;
  int rc = SQLITE_OK;
  int i;

  /* Assert that malloc() has not failed */
  assert( !db->mallocFailed );

  assert( ppStmt );
  *ppStmt = 0;
  if( sqlite3SafetyOn(db) ){
    return SQLITE_MISUSE;
  }

  assert( sqlite3_mutex_held(db->mutex) );

  /* If any attached database schemas are locked, do not proceed with
  ** compilation. Instead return SQLITE_LOCKED immediately.
  */
  for(i=0; i<db->nDb; i++) {
    Btree *pBt = db->aDb[i].pBt;

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the implementation of the sqlite3_prepare()
** interface, and routines that contribute to loading the database schema
** from disk.
**
** $Id: prepare.c,v 1.57 2007/08/22 00:39:20 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates
** that the database is corrupt.
................................................................................
  const char **pzTail       /* OUT: End of parsed string */
){
  Parse sParse;
  char *zErrMsg = 0;
  int rc = SQLITE_OK;
  int i;




  assert( ppStmt );
  *ppStmt = 0;
  if( sqlite3SafetyOn(db) ){
    return SQLITE_MISUSE;
  }
  assert( !db->mallocFailed );
  assert( sqlite3_mutex_held(db->mutex) );

  /* If any attached database schemas are locked, do not proceed with
  ** compilation. Instead return SQLITE_LOCKED immediately.
  */
  for(i=0; i<db->nDb; i++) {
    Btree *pBt = db->aDb[i].pBt;

** on how SQLite interfaces are suppose to operate.
**
** The name of this file under configuration management is "sqlite.h.in".
** The makefile makes some minor changes to this file (such as inserting
** the version number) and changes its name to "sqlite3.h" as
** part of the build process.
**
** @(#) $Id: sqlite.h.in,v 1.235 2007/08/21 20:25:40 drh Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.
................................................................................
** to sqlite3_mutex_alloc() is one of these integer constants:
**
** <ul>
** <li>  SQLITE_MUTEX_FAST
** <li>  SQLITE_MUTEX_RECURSIVE
** <li>  SQLITE_MUTEX_STATIC_MASTER
** <li>  SQLITE_MUTEX_STATIC_MEM

** <li>  SQLITE_MUTEX_STATIC_PRNG
** </ul>
**
** The first two constants cause sqlite3_mutex_alloc() to create
** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
** The mutex implementation does not need to make a distinction
................................................................................
**
** The [sqlite3_mutex_alloc()] interface takes a single argument
** which is one of these integer constants.
*/
#define SQLITE_MUTEX_FAST             0
#define SQLITE_MUTEX_RECURSIVE        1
#define SQLITE_MUTEX_STATIC_MASTER    2
#define SQLITE_MUTEX_STATIC_MEM       3

#define SQLITE_MUTEX_STATIC_PRNG      4


/*
** Undo the hack that converts floating point types to integer for
** builds on processors without floating point support.
*/
#ifdef SQLITE_OMIT_FLOATING_POINT

** on how SQLite interfaces are suppose to operate.
**
** The name of this file under configuration management is "sqlite.h.in".
** The makefile makes some minor changes to this file (such as inserting
** the version number) and changes its name to "sqlite3.h" as
** part of the build process.
**
** @(#) $Id: sqlite.h.in,v 1.236 2007/08/22 00:39:20 drh Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.
................................................................................
** to sqlite3_mutex_alloc() is one of these integer constants:
**
** <ul>
** <li>  SQLITE_MUTEX_FAST
** <li>  SQLITE_MUTEX_RECURSIVE
** <li>  SQLITE_MUTEX_STATIC_MASTER
** <li>  SQLITE_MUTEX_STATIC_MEM
** <li>  SQLITE_MUTEX_STATIC_MEM2
** <li>  SQLITE_MUTEX_STATIC_PRNG
** </ul>
**
** The first two constants cause sqlite3_mutex_alloc() to create
** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
** The mutex implementation does not need to make a distinction
................................................................................
**
** The [sqlite3_mutex_alloc()] interface takes a single argument
** which is one of these integer constants.
*/
#define SQLITE_MUTEX_FAST             0
#define SQLITE_MUTEX_RECURSIVE        1
#define SQLITE_MUTEX_STATIC_MASTER    2
#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
#define SQLITE_MUTEX_STATIC_MEM2      4  /* sqlite3_release_memory() */
#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */


/*
** Undo the hack that converts floating point types to integer for
** builds on processors without floating point support.
*/
#ifdef SQLITE_OMIT_FLOATING_POINT

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** A TCL Interface to SQLite.  Append this file to sqlite3.c and
** compile the whole thing to build a TCL-enabled version of SQLite.
**
** $Id: tclsqlite.c,v 1.196 2007/08/21 10:44:16 drh Exp $
*/
#include "tcl.h"
#include <errno.h>

/*
** Some additional include files are needed if this file is not
** appended to the amalgamation.
................................................................................

  /* If compiled with SQLITE_TEST turned on, then register the "md5sum"
  ** SQL function.
  */
#ifdef SQLITE_TEST
  {
    extern void Md5_Register(sqlite3*);
#ifdef SQLITE_MEMDEBUG
    int mallocfail = sqlite3_iMallocFail;
    sqlite3_iMallocFail = 0;
#endif
    Md5_Register(p->db);
#ifdef SQLITE_MEMDEBUG
    sqlite3_iMallocFail = mallocfail;
#endif
  }
#endif  
  return TCL_OK;
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** A TCL Interface to SQLite.  Append this file to sqlite3.c and
** compile the whole thing to build a TCL-enabled version of SQLite.
**
** $Id: tclsqlite.c,v 1.197 2007/08/22 00:39:21 drh Exp $
*/
#include "tcl.h"
#include <errno.h>

/*
** Some additional include files are needed if this file is not
** appended to the amalgamation.
................................................................................

  /* If compiled with SQLITE_TEST turned on, then register the "md5sum"
  ** SQL function.
  */
#ifdef SQLITE_TEST
  {
    extern void Md5_Register(sqlite3*);
#if 0
    int mallocfail = sqlite3_iMallocFail;
    sqlite3_iMallocFail = 0;
#endif
    Md5_Register(p->db);
#if 0
    sqlite3_iMallocFail = mallocfail;
#endif
  }
#endif  
  return TCL_OK;
}

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing all sorts of SQLite interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.267 2007/08/21 19:33:57 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

/*
................................................................................
  }

#ifndef SQLITE_OMIT_UTF16
  /* Use the sqlite3_create_function16() API here. Mainly for fun, but also 
  ** because it is not tested anywhere else. */
  if( rc==SQLITE_OK ){
    sqlite3_value *pVal;
#if 0
    if( sqlite3_iMallocFail>0 ){
      sqlite3_iMallocFail++;
    }
#endif 
    pVal = sqlite3ValueNew(db);
    sqlite3ValueSetStr(pVal, -1, "x_sqlite_exec", SQLITE_UTF8, SQLITE_STATIC);
    rc = sqlite3_create_function16(db, 
              sqlite3ValueText(pVal, SQLITE_UTF16NATIVE),
              1, SQLITE_UTF16, db, sqlite3ExecFunc, 0, 0);
    sqlite3ValueFree(pVal);
  }
................................................................................
          (void *)SQLITE_UTF8, val?test_collate_func:0);
  if( rc==SQLITE_OK ){
    if( TCL_OK!=Tcl_GetBooleanFromObj(interp, objv[3], &val) ) return TCL_ERROR;
    rc = sqlite3_create_collation(db, "test_collate", SQLITE_UTF16LE, 
            (void *)SQLITE_UTF16LE, val?test_collate_func:0);
    if( TCL_OK!=Tcl_GetBooleanFromObj(interp, objv[4], &val) ) return TCL_ERROR;

#ifdef SQLITE_MEMDEBUG
    if( sqlite3_iMallocFail>0 ){
      sqlite3_iMallocFail++;
    }
#endif
    pVal = sqlite3ValueNew(0);
    sqlite3ValueSetStr(pVal, -1, "test_collate", SQLITE_UTF8, SQLITE_STATIC);
    rc = sqlite3_create_collation16(db, 
................................................................................
*/
static int test_soft_heap_limit(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
  int amt;
  if( objc!=1 && objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?N?");
    return TCL_ERROR;
  }
  amt = sqlite3ThreadDataReadOnly()->nSoftHeapLimit;
  if( objc==2 ){
    int N;
    if( Tcl_GetIntFromObj(interp, objv[1], &N) ) return TCL_ERROR;
    sqlite3_soft_heap_limit(N);

  }
  Tcl_SetObjResult(interp, Tcl_NewIntObj(amt));
#endif
  return TCL_OK;
}

/*
** Usage:   sqlite3_clear_tsd_memdebug
**
** Clear all of the MEMDEBUG information out of thread-specific data.
................................................................................
*/
static int test_tsd_release(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
#if defined(SQLITE_MEMDEBUG)
  sqlite3ReleaseThreadData();
#endif
  return TCL_OK;
}

/*
** Usage:   sqlite3_thread_cleanup
**
** Call the sqlite3_thread_cleanup API.
................................................................................
#endif
  };
  static int bitmask_size = sizeof(Bitmask)*8;
  int i;
  extern int sqlite3_where_trace;
  extern int sqlite3_sync_count, sqlite3_fullsync_count;
  extern int sqlite3_opentemp_count;
  extern int sqlite3_memUsed;
  extern int sqlite3_memMax;
  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;
  extern int sqlite3_pager_pgfree_count;
#if OS_UNIX && defined(SQLITE_TEST) && SQLITE_THREADSAFE
................................................................................
  Tcl_LinkVar(interp, "sqlite_addop_trace",
      (char*)&sqlite3_vdbe_addop_trace, TCL_LINK_INT);
  Tcl_LinkVar(interp, "sqlite_where_trace",
      (char*)&sqlite3_where_trace, TCL_LINK_INT);
  Tcl_LinkVar(interp, "sqlite_os_trace",
      (char*)&sqlite3_os_trace, TCL_LINK_INT);
#endif
#ifdef SQLITE_MEMDEBUG
  Tcl_LinkVar(interp, "sqlite_memused",
      (char*)&sqlite3_memUsed, TCL_LINK_INT | TCL_LINK_READ_ONLY);
  Tcl_LinkVar(interp, "sqlite_memmax",
      (char*)&sqlite3_memMax, TCL_LINK_INT | TCL_LINK_READ_ONLY);
#endif
#ifndef SQLITE_OMIT_DISKIO
  Tcl_LinkVar(interp, "sqlite_opentemp_count",
      (char*)&sqlite3_opentemp_count, TCL_LINK_INT);
#endif
  Tcl_LinkVar(interp, "sqlite_static_bind_value",
      (char*)&sqlite_static_bind_value, TCL_LINK_STRING);
  Tcl_LinkVar(interp, "sqlite_static_bind_nbyte",

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing all sorts of SQLite interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.268 2007/08/22 00:39:21 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

/*
................................................................................
  }

#ifndef SQLITE_OMIT_UTF16
  /* Use the sqlite3_create_function16() API here. Mainly for fun, but also 
  ** because it is not tested anywhere else. */
  if( rc==SQLITE_OK ){
    sqlite3_value *pVal;





    pVal = sqlite3ValueNew(db);
    sqlite3ValueSetStr(pVal, -1, "x_sqlite_exec", SQLITE_UTF8, SQLITE_STATIC);
    rc = sqlite3_create_function16(db, 
              sqlite3ValueText(pVal, SQLITE_UTF16NATIVE),
              1, SQLITE_UTF16, db, sqlite3ExecFunc, 0, 0);
    sqlite3ValueFree(pVal);
  }
................................................................................
          (void *)SQLITE_UTF8, val?test_collate_func:0);
  if( rc==SQLITE_OK ){
    if( TCL_OK!=Tcl_GetBooleanFromObj(interp, objv[3], &val) ) return TCL_ERROR;
    rc = sqlite3_create_collation(db, "test_collate", SQLITE_UTF16LE, 
            (void *)SQLITE_UTF16LE, val?test_collate_func:0);
    if( TCL_OK!=Tcl_GetBooleanFromObj(interp, objv[4], &val) ) return TCL_ERROR;

#if 0
    if( sqlite3_iMallocFail>0 ){
      sqlite3_iMallocFail++;
    }
#endif
    pVal = sqlite3ValueNew(0);
    sqlite3ValueSetStr(pVal, -1, "test_collate", SQLITE_UTF8, SQLITE_STATIC);
    rc = sqlite3_create_collation16(db, 
................................................................................
*/
static int test_soft_heap_limit(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  static int softHeapLimit = 0;
  int amt;
  if( objc!=1 && objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?N?");
    return TCL_ERROR;
  }
  amt = softHeapLimit;
  if( objc==2 ){
    int N;
    if( Tcl_GetIntFromObj(interp, objv[1], &N) ) return TCL_ERROR;
    sqlite3_soft_heap_limit(N);
    softHeapLimit = N;
  }
  Tcl_SetObjResult(interp, Tcl_NewIntObj(amt));

  return TCL_OK;
}

/*
** Usage:   sqlite3_clear_tsd_memdebug
**
** Clear all of the MEMDEBUG information out of thread-specific data.
................................................................................
*/
static int test_tsd_release(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){



  return TCL_OK;
}

/*
** Usage:   sqlite3_thread_cleanup
**
** Call the sqlite3_thread_cleanup API.
................................................................................
#endif
  };
  static int bitmask_size = sizeof(Bitmask)*8;
  int i;
  extern int sqlite3_where_trace;
  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;
  extern int sqlite3_pager_pgfree_count;
#if OS_UNIX && defined(SQLITE_TEST) && SQLITE_THREADSAFE
................................................................................
  Tcl_LinkVar(interp, "sqlite_addop_trace",
      (char*)&sqlite3_vdbe_addop_trace, TCL_LINK_INT);
  Tcl_LinkVar(interp, "sqlite_where_trace",
      (char*)&sqlite3_where_trace, TCL_LINK_INT);
  Tcl_LinkVar(interp, "sqlite_os_trace",
      (char*)&sqlite3_os_trace, TCL_LINK_INT);
#endif






#ifndef SQLITE_OMIT_DISKIO
  Tcl_LinkVar(interp, "sqlite_opentemp_count",
      (char*)&sqlite3_opentemp_count, TCL_LINK_INT);
#endif
  Tcl_LinkVar(interp, "sqlite_static_bind_value",
      (char*)&sqlite_static_bind_value, TCL_LINK_STRING);
  Tcl_LinkVar(interp, "sqlite_static_bind_nbyte",

*/
int sqlite3_finalize(sqlite3_stmt *pStmt){
  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;

    sqlite3_mutex_enter(v->db->mutex);
    rc = sqlite3VdbeFinalize(v);
    sqlite3_mutex_leave(v->db->mutex);
  }
  return rc;
}

/*
** Terminate the current execution of an SQL statement and reset it
** back to its starting state so that it can be reused. A success code from

*/
int sqlite3_finalize(sqlite3_stmt *pStmt){
  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;
    sqlite3_mutex *mutex = v->db->mutex;
    sqlite3_mutex_enter(mutex);
    rc = sqlite3VdbeFinalize(v);
    sqlite3_mutex_leave(mutex);
  }
  return rc;
}

/*
** Terminate the current execution of an SQL statement and reset it
** back to its starting state so that it can be reused. A success code from

#    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 the callback-free C/C++ API.
#
# $Id: capi2.test,v 1.33 2007/01/03 23:37:29 drh Exp $
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Return the text values from the current row pointed at by STMT as a list.
proc get_row_values {STMT} {
................................................................................
# finalized. Is this going to cause trouble for anyone? Lee Nelson maybe?
# (Later:) The change now happens just before SQLITE_DONE is returned.
do_test capi2-3.10b {db changes} {1}
do_test capi2-3.11 {
  sqlite3_finalize $VM
} {SQLITE_OK}
do_test capi2-3.11b {db changes} {1}
do_test capi2-3.12-misuse {
  sqlite3_finalize $VM
} {SQLITE_MISUSE}
do_test capi2-3.13 {
  set VM [sqlite3_prepare $DB {INSERT INTO t1 VALUES(1,3,4)} -1 TAIL]
  list [sqlite3_step $VM] \
       [sqlite3_column_count $VM] \
       [get_row_values $VM] \
       [get_column_names $VM]
} {SQLITE_ERROR 0 {} {}}

#    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 the callback-free C/C++ API.
#
# $Id: capi2.test,v 1.34 2007/08/22 00:39:21 drh Exp $
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Return the text values from the current row pointed at by STMT as a list.
proc get_row_values {STMT} {
................................................................................
# finalized. Is this going to cause trouble for anyone? Lee Nelson maybe?
# (Later:) The change now happens just before SQLITE_DONE is returned.
do_test capi2-3.10b {db changes} {1}
do_test capi2-3.11 {
  sqlite3_finalize $VM
} {SQLITE_OK}
do_test capi2-3.11b {db changes} {1}
#do_test capi2-3.12-misuse {
#  sqlite3_finalize $VM
#} {SQLITE_MISUSE}
do_test capi2-3.13 {
  set VM [sqlite3_prepare $DB {INSERT INTO t1 VALUES(1,3,4)} -1 TAIL]
  list [sqlite3_step $VM] \
       [sqlite3_column_count $VM] \
       [get_row_values $VM] \
       [get_column_names $VM]
} {SQLITE_ERROR 0 {} {}}