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Overview
Comment:Make the OsFile structure opaque with its internal structure known only to the appropriate os_*.c implementation. Omit the os_unix.h and os_win.h include files. The crash tests are broken by this patch. (CVS 2791)
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SHA1:058f31753871b16b40fe4048e3adcee411e0f87d
User & Date: drh 2005-11-29 03:13:21
Context
2005-11-29
18:37
The crash tests now compile, at least. But they get wrong results. The problem is fundamental and suggests I need to completely rethink how the new OS backend should work. (CVS 2792) check-in: 966bc68e user: drh tags: trunk
03:13
Make the OsFile structure opaque with its internal structure known only to the appropriate os_*.c implementation. Omit the os_unix.h and os_win.h include files. The crash tests are broken by this patch. (CVS 2791) check-in: 058f3175 user: drh tags: trunk
2005-11-28
12:36
Replace a call to sprintf() with sqlite3MPrintf() since on some embedded platforms, sprintf() is busted. Need to go through and do similar replacements elsewhere in the code. (CVS 2790) check-in: 1b4f2d89 user: drh tags: trunk
Changes
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Changes to Makefile.in.

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HDR = \
   sqlite3.h  \
   $(TOP)/src/btree.h \
   $(TOP)/src/hash.h \
   opcodes.h \
   $(TOP)/src/os.h \
   $(TOP)/src/os_common.h \
   $(TOP)/src/os_unix.h \
   $(TOP)/src/os_win.h \
   $(TOP)/src/sqliteInt.h  \
   $(TOP)/src/vdbe.h \
   parse.h

# Header files used by the VDBE submodule
#
VDBEHDR = \







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HDR = \
   sqlite3.h  \
   $(TOP)/src/btree.h \
   $(TOP)/src/hash.h \
   opcodes.h \
   $(TOP)/src/os.h \
   $(TOP)/src/os_common.h \


   $(TOP)/src/sqliteInt.h  \
   $(TOP)/src/vdbe.h \
   parse.h

# Header files used by the VDBE submodule
#
VDBEHDR = \

Changes to main.mk.

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HDR = \
   sqlite3.h  \
   $(TOP)/src/btree.h \
   $(TOP)/src/hash.h \
   opcodes.h \
   $(TOP)/src/os.h \
   $(TOP)/src/os_common.h \
   $(TOP)/src/os_unix.h \
   $(TOP)/src/os_win.h \
   $(TOP)/src/sqliteInt.h  \
   $(TOP)/src/vdbe.h \
   parse.h

# Header files used by the VDBE submodule
#
VDBEHDR = \







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HDR = \
   sqlite3.h  \
   $(TOP)/src/btree.h \
   $(TOP)/src/hash.h \
   opcodes.h \
   $(TOP)/src/os.h \
   $(TOP)/src/os_common.h \


   $(TOP)/src/sqliteInt.h  \
   $(TOP)/src/vdbe.h \
   parse.h

# Header files used by the VDBE submodule
#
VDBEHDR = \

Changes to src/expr.c.

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**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.239 2005/11/28 12:36:36 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
struct QueryCoder {
  Parse *pParse;       /* The parsing context */
  NameContext *pNC;    /* Namespace of first enclosing query */
};


/*
** Generate code for subqueries and IN operators.
**
** IN operators comes in two forms:
**

**           expr IN (exprlist)
** and
**           expr IN (SELECT ...)
**
** The first form is handled by creating a set holding the list
** of allowed values.  The second form causes the SELECT to generate 
** a temporary table.
*/
#ifndef SQLITE_OMIT_SUBQUERY
void sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
  int testAddr = 0;                       /* One-time test address */
  Vdbe *v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;








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**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.240 2005/11/29 03:13:22 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
struct QueryCoder {
  Parse *pParse;       /* The parsing context */
  NameContext *pNC;    /* Namespace of first enclosing query */
};


/*
** Generate code for scalar subqueries used as an expression

** and IN operators.  Examples:
**
**     (SELECT a FROM b)          -- subquery
**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
**     x IN (4,5,11)              -- IN operator with list on right-hand side
**     x IN (SELECT a FROM b)     -- IN operator with subquery on the right
**
** The pExpr parameter describes the expression that contains the IN
** operator or subquery.

*/
#ifndef SQLITE_OMIT_SUBQUERY
void sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
  int testAddr = 0;                       /* One-time test address */
  Vdbe *v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;

Changes to src/os.h.

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#else
# ifndef OS_WIN
#  define OS_WIN 0
# endif
#endif

/*
** Invoke the appropriate operating-system specific header file.
*/
#if OS_ALT
# include "os_alt.h"
#endif
#if OS_UNIX
# include "os_unix.h"
#endif
#if OS_WIN
# include "os_win.h"
#endif

/* os_other.c and os_other.h are not delivered with SQLite.  These files
** are place-holders that can be filled in by third-party developers to
** implement backends to their on proprietary operating systems.


*/
#if OS_OTHER
# include "os_other.h"



#endif

/* If the SET_FULLSYNC macro is not defined above, then make it
** a no-op
*/
#ifndef SET_FULLSYNC
# define SET_FULLSYNC(x,y)
................................................................................
/*
** A single global instance of the following structure holds pointers to the
** various disk I/O routines.
*/
extern struct sqlite3IoVtbl {
  int (*xDelete)(const char*);
  int (*xFileExists)(const char*);
  int (*xOpenReadWrite)(const char*, OsFile*, int*);
  int (*xOpenExclusive)(const char*, OsFile*, int);
  int (*xOpenReadOnly)(const char*, OsFile*);
  int (*xOpenDirectory)(const char*, OsFile*);
  int (*xSyncDirectory)(const char*);
  int (*xTempFileName)(char*);
  int (*xIsDirWritable)(char*);
  int (*xClose)(OsFile*);
  int (*xRead)(OsFile*, void*, int amt);
  int (*xWrite)(OsFile*, const void*, int amt);
  int (*xSeek)(OsFile*, i64 offset);
  int (*xSync)(OsFile*, int);
  int (*xTruncate)(OsFile*, i64 size);
  int (*xFileSize)(OsFile*, i64 *pSize);
  char *(*xFullPathname)(const char*);
  int (*xLock)(OsFile*, int);
  int (*xUnlock)(OsFile*, int);
  int (*xCheckReservedLock)(OsFile *id);
  void (*xCopyOsFile)(OsFile *pDest, OsFile *pSrc);


} sqlite3Io;

/* The interface for file I/O is above.  Other miscellaneous functions
** are below */

int sqlite3OsRandomSeed(char*);
int sqlite3OsSleep(int ms);
int sqlite3OsCurrentTime(double*);
void sqlite3OsEnterMutex(void);
void sqlite3OsLeaveMutex(void);


#endif /* _SQLITE_OS_H_ */







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#else
# ifndef OS_WIN
#  define OS_WIN 0
# endif
#endif

/*
** The OsFile object describes an open disk file in an OS-dependent way.
*/
typedef struct OsFile OsFile;












/*
** Define the maximum size of a temporary filename
*/
#if OS_WIN

# define SQLITE_TEMPNAME_SIZE (MAX_PATH+50)
#else
# define SQLITE_TEMPNAME_SIZE 200
#endif

/* If the SET_FULLSYNC macro is not defined above, then make it
** a no-op
*/
#ifndef SET_FULLSYNC
# define SET_FULLSYNC(x,y)
................................................................................
/*
** A single global instance of the following structure holds pointers to the
** various disk I/O routines.
*/
extern struct sqlite3IoVtbl {
  int (*xDelete)(const char*);
  int (*xFileExists)(const char*);
  int (*xOpenReadWrite)(const char*, OsFile**, int*);
  int (*xOpenExclusive)(const char*, OsFile**, int);
  int (*xOpenReadOnly)(const char*, OsFile**);
  int (*xOpenDirectory)(const char*, OsFile*);
  int (*xSyncDirectory)(const char*);
  int (*xTempFileName)(char*);
  int (*xIsDirWritable)(char*);
  int (*xClose)(OsFile**);
  int (*xRead)(OsFile*, void*, int amt);
  int (*xWrite)(OsFile*, const void*, int amt);
  int (*xSeek)(OsFile*, i64 offset);
  int (*xSync)(OsFile*, int);
  int (*xTruncate)(OsFile*, i64 size);
  int (*xFileSize)(OsFile*, i64 *pSize);
  char *(*xFullPathname)(const char*);
  int (*xLock)(OsFile*, int);
  int (*xUnlock)(OsFile*, int);
  int (*xCheckReservedLock)(OsFile *id);
  void (*xSetFullSync)(OsFile *id, int setting);
  int (*xFileHandle)(OsFile *id);
  int (*xLockState)(OsFile *id);
} sqlite3Io;

/* The interface for file I/O is above.  Other miscellaneous functions
** are below */

int sqlite3OsRandomSeed(char*);
int sqlite3OsSleep(int ms);
int sqlite3OsCurrentTime(double*);
void sqlite3OsEnterMutex(void);
void sqlite3OsLeaveMutex(void);


#endif /* _SQLITE_OS_H_ */

Changes to src/os_unix.c.

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******************************************************************************
**
** This file contains code that is specific to Unix systems.
*/
#include "sqliteInt.h"
#include "os.h"
#if OS_UNIX              /* This file is used on unix only */































#include <time.h>
#include <sys/time.h>
#include <errno.h>








#include <unistd.h>



































/*
** Do not include any of the File I/O interface procedures if the
** SQLITE_OMIT_DISKIO macro is defined (indicating that there database
** will be in-memory only)
*/
#ifndef SQLITE_OMIT_DISKIO
................................................................................
** same thread is operating on the OsFile.  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.  This logic makes sure a user does not try to do that
** by mistake.
*/
#if defined(SQLITE_UNIX_THREADS) && !defined(SQLITE_ALLOW_XTHREAD_CONNECTIONS)
# define SET_THREADID(X)   X->tid = pthread_self()
# define CHECK_THREADID(X) (!pthread_equal(X->tid, pthread_self()))
#else
# define SET_THREADID(X)
# define CHECK_THREADID(X) 0
#endif

/*
** Here is the dirt on POSIX advisory locks:  ANSI STD 1003.1 (1996)
................................................................................

/*
** Return TRUE if the named file exists.
*/
static int unixFileExists(const char *zFilename){
  return access(zFilename, 0)==0;
}

















/*
** Attempt to open a file for both reading and writing.  If that
** fails, try opening it read-only.  If the file does not exist,
** try to create it.
**
** On success, a handle for the open file is written to *id
................................................................................
** SQLITE_OK.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id and *pReadonly unchanged.
*/
static int unixOpenReadWrite(
  const char *zFilename,
  OsFile *id,
  int *pReadonly
){
  int rc;


  assert( !id->isOpen );
  id->dirfd = -1;
  SET_THREADID(id);
  id->h = open(zFilename, O_RDWR|O_CREAT|O_LARGEFILE|O_BINARY,
                          SQLITE_DEFAULT_FILE_PERMISSIONS);
  if( id->h<0 ){
#ifdef EISDIR
    if( errno==EISDIR ){
      return SQLITE_CANTOPEN;
    }
#endif
    id->h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
    if( id->h<0 ){
      return SQLITE_CANTOPEN; 
    }
    *pReadonly = 1;
  }else{
    *pReadonly = 0;
  }
  sqlite3OsEnterMutex();
  rc = findLockInfo(id->h, &id->pLock, &id->pOpen);
  sqlite3OsLeaveMutex();
  if( rc ){
    close(id->h);
    return SQLITE_NOMEM;
  }
  id->locktype = 0;
  id->isOpen = 1;
  TRACE3("OPEN    %-3d %s\n", id->h, zFilename);




  OpenCounter(+1);
  return SQLITE_OK;

}


/*
** Attempt to open a new file for exclusive access by this process.
** The file will be opened for both reading and writing.  To avoid
** a potential security problem, we do not allow the file to have
................................................................................
** If delFlag is true, then make arrangements to automatically delete
** the file when it is closed.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int unixOpenExclusive(const char *zFilename, OsFile *id, int delFlag){
  int rc;


  assert( !id->isOpen );
  if( access(zFilename, 0)==0 ){
    return SQLITE_CANTOPEN;
  }
  SET_THREADID(id);
  id->dirfd = -1;
  id->h = open(zFilename,
                O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW|O_LARGEFILE|O_BINARY,
                SQLITE_DEFAULT_FILE_PERMISSIONS);
  if( id->h<0 ){
    return SQLITE_CANTOPEN;
  }
  sqlite3OsEnterMutex();
  rc = findLockInfo(id->h, &id->pLock, &id->pOpen);
  sqlite3OsLeaveMutex();
  if( rc ){
    close(id->h);
    unlink(zFilename);
    return SQLITE_NOMEM;
  }
  id->locktype = 0;
  id->isOpen = 1;
  if( delFlag ){
    unlink(zFilename);
  }
  TRACE3("OPEN-EX %-3d %s\n", id->h, zFilename);




  OpenCounter(+1);
  return SQLITE_OK;

}

/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int unixOpenReadOnly(const char *zFilename, OsFile *id){
  int rc;


  assert( !id->isOpen );
  SET_THREADID(id);
  id->dirfd = -1;
  id->h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
  if( id->h<0 ){
    return SQLITE_CANTOPEN;
  }
  sqlite3OsEnterMutex();
  rc = findLockInfo(id->h, &id->pLock, &id->pOpen);
  sqlite3OsLeaveMutex();
  if( rc ){
    close(id->h);
    return SQLITE_NOMEM;
  }
  id->locktype = 0;
  id->isOpen = 1;
  TRACE3("OPEN-RO %-3d %s\n", id->h, zFilename);




  OpenCounter(+1);
  return SQLITE_OK;

}

/*
** Attempt to open a file descriptor for the directory that contains a
** file.  This file descriptor can be used to fsync() the directory
** in order to make sure the creation of a new file is actually written
** to disk.
**
** This routine is only meaningful for Unix.  It is a no-op under
** windows since windows does not support hard links.
**
** On success, a handle for a previously open file is at *id is
** updated with the new directory file descriptor and SQLITE_OK is
** returned.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id unchanged.
*/
static int unixOpenDirectory(
  const char *zDirname,
  OsFile *id
){
  if( !id->isOpen ){
    /* Do not open the directory if the corresponding file is not already
    ** open. */
    return SQLITE_CANTOPEN;
  }
  SET_THREADID(id);
  assert( id->dirfd<0 );
  id->dirfd = open(zDirname, O_RDONLY|O_BINARY, 0);
................................................................................
/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
static int unixRead(OsFile *id, void *pBuf, int amt){
  int got;
  assert( id->isOpen );
  SimulateIOError(SQLITE_IOERR);
  TIMER_START;
  got = read(id->h, pBuf, amt);
  TIMER_END;
  TRACE5("READ    %-3d %5d %7d %d\n", id->h, got, last_page, TIMER_ELAPSED);
  SEEK(0);
  /* if( got<0 ) got = 0; */
................................................................................

/*
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
*/
static int unixWrite(OsFile *id, const void *pBuf, int amt){
  int wrote = 0;
  assert( id->isOpen );
  assert( amt>0 );
  SimulateIOError(SQLITE_IOERR);
  SimulateDiskfullError;
  TIMER_START;
  while( amt>0 && (wrote = write(id->h, pBuf, amt))>0 ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
................................................................................
  return SQLITE_OK;
}

/*
** Move the read/write pointer in a file.
*/
static int unixSeek(OsFile *id, i64 offset){
  assert( id->isOpen );
  SEEK(offset/1024 + 1);
#ifdef SQLITE_TEST
  if( offset ) SimulateDiskfullError
#endif
  lseek(id->h, offset, SEEK_SET);
  return SQLITE_OK;
}
................................................................................
** If we do not do this and we encounter a power failure, the directory
** entry for the journal might not exist after we reboot.  The next
** SQLite to access the file will not know that the journal exists (because
** the directory entry for the journal was never created) and the transaction
** will not roll back - possibly leading to database corruption.
*/
static int unixSync(OsFile *id, int dataOnly){
  assert( id->isOpen );
  SimulateIOError(SQLITE_IOERR);
  TRACE2("SYNC    %-3d\n", id->h);
  if( full_fsync(id->h, id->fullSync, dataOnly) ){
    return SQLITE_IOERR;
  }
  if( id->dirfd>=0 ){
    TRACE2("DIRSYNC %-3d\n", id->dirfd);
................................................................................
#endif
}

/*
** Truncate an open file to a specified size
*/
static int unixTruncate(OsFile *id, i64 nByte){
  assert( id->isOpen );
  SimulateIOError(SQLITE_IOERR);
  return ftruncate(id->h, nByte)==0 ? SQLITE_OK : SQLITE_IOERR;
}

/*
** Determine the current size of a file in bytes
*/
static int unixFileSize(OsFile *id, i64 *pSize){
  struct stat buf;
  assert( id->isOpen );
  SimulateIOError(SQLITE_IOERR);
  if( fstat(id->h, &buf)!=0 ){
    return SQLITE_IOERR;
  }
  *pSize = buf.st_size;
  return SQLITE_OK;
}
................................................................................
** file by this or any other process. If such a lock is held, return
** non-zero.  If the file is unlocked or holds only SHARED locks, then
** return zero.
*/
static int unixCheckReservedLock(OsFile *id){
  int r = 0;

  assert( id->isOpen );
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;
  sqlite3OsEnterMutex(); /* Needed because id->pLock is shared across threads */

  /* Check if a thread in this process holds such a lock */
  if( id->pLock->locktype>SHARED_LOCK ){
    r = 1;
  }
................................................................................
  ** even if the locking primitive used is always a write-lock.
  */
  int rc = SQLITE_OK;
  struct lockInfo *pLock = id->pLock;
  struct flock lock;
  int s;

  assert( id->isOpen );
  TRACE7("LOCK    %d %s was %s(%s,%d) pid=%d\n", id->h, locktypeName(locktype), 
      locktypeName(id->locktype), locktypeName(pLock->locktype), pLock->cnt
      ,getpid() );
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as
................................................................................
** might return SQLITE_IOERR instead of SQLITE_OK.
*/
static int unixUnlock(OsFile *id, int locktype){
  struct lockInfo *pLock;
  struct flock lock;
  int rc = SQLITE_OK;

  assert( id->isOpen );
  TRACE7("UNLOCK  %d %d was %d(%d,%d) pid=%d\n", id->h, locktype, id->locktype, 
      id->pLock->locktype, id->pLock->cnt, getpid());
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;

  assert( locktype<=SHARED_LOCK );
  if( id->locktype<=locktype ){
    return SQLITE_OK;
................................................................................
  id->locktype = locktype;
  return rc;
}

/*
** Close a file.
*/
static int unixClose(OsFile *id){

  if( !id->isOpen ) return SQLITE_OK;
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;
  sqlite3Io.xUnlock(id, NO_LOCK);
  if( id->dirfd>=0 ) close(id->dirfd);
  id->dirfd = -1;
  sqlite3OsEnterMutex();
  if( id->pOpen->nLock ){
    /* If there are outstanding locks, do not actually close the file just
................................................................................
  }
  releaseLockInfo(id->pLock);
  releaseOpenCnt(id->pOpen);
  sqlite3OsLeaveMutex();
  id->isOpen = 0;
  TRACE2("CLOSE   %-3d\n", id->h);
  OpenCounter(-1);


  return SQLITE_OK;
}

/*
** Turn a relative pathname into a full pathname.  Return a pointer
** to the full pathname stored in space obtained from sqliteMalloc().
** The calling function is responsible for freeing this space once it
................................................................................
                    (char*)0);
    sqliteFree(zBuf);
  }
  return zFull;
}

/*
** Make a copy of an OsFile object.
*/
static void unixCopyOsFile(OsFile *pDest, OsFile *pSrc){
  *pDest = *pSrc;















}

/*
** This is the structure that defines all of the I/O routines.
*/
struct sqlite3IoVtbl sqlite3Io = {
  unixDelete,
................................................................................
  unixSync,
  unixTruncate,
  unixFileSize,
  unixFullPathname,
  unixLock,
  unixUnlock,
  unixCheckReservedLock,
  unixCopyOsFile,


};


#endif /* SQLITE_OMIT_DISKIO */
/***************************************************************************
** Everything above deals with file I/O.  Everything that follows deals
** with other miscellanous aspects of the operating system interface







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******************************************************************************
**
** This file contains code that is specific to Unix systems.
*/
#include "sqliteInt.h"
#include "os.h"
#if OS_UNIX              /* This file is used on unix only */
/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it.  If the OS lacks
** large file support, or if the OS is windows, these should be no-ops.
**
** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
** on the compiler command line.  This is necessary if you are compiling
** on a recent machine (ex: RedHat 7.2) but you want your code to work
** on an older machine (ex: RedHat 6.0).  If you compile on RedHat 7.2
** without this option, LFS is enable.  But LFS does not exist in the kernel
** in RedHat 6.0, so the code won't work.  Hence, for maximum binary
** portability you should omit LFS.
**
** Similar is true for MacOS.  LFS is only supported on MacOS 9 and later.
*/
#ifndef SQLITE_DISABLE_LFS
# define _LARGE_FILE       1
# ifndef _FILE_OFFSET_BITS
#   define _FILE_OFFSET_BITS 64
# endif
# define _LARGEFILE_SOURCE 1
#endif


/*
** standard include files.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <time.h>
#include <sys/time.h>
#include <errno.h>

/*
** Macros used to determine whether or not to use threads.  The
** SQLITE_UNIX_THREADS macro is defined if we are synchronizing for
** Posix threads and SQLITE_W32_THREADS is defined if we are
** synchronizing using Win32 threads.
*/
#if defined(THREADSAFE) && THREADSAFE
# include <pthread.h>
# define SQLITE_UNIX_THREADS 1
#endif

/*
** Default permissions when creating a new file
*/
#ifndef SQLITE_DEFAULT_FILE_PERMISSIONS
# define SQLITE_DEFAULT_FILE_PERMISSIONS 0644
#endif



/*
** The OsFile structure is a operating-system dependent representation
** of an open file handle.  It is defined differently for each architecture.
**
** This is the definition for Unix.
**
** OsFile.locktype takes one of the values SHARED_LOCK, RESERVED_LOCK,
** PENDING_LOCK or EXCLUSIVE_LOCK.
*/
struct OsFile {
  struct openCnt *pOpen;    /* Info about all open fd's on this inode */
  struct lockInfo *pLock;   /* Info about locks on this inode */
  int h;                    /* The file descriptor */
  unsigned char locktype;   /* The type of lock held on this fd */
  unsigned char isOpen;     /* True if needs to be closed */
  unsigned char fullSync;   /* Use F_FULLSYNC if available */
  int dirfd;                /* File descriptor for the directory */
#ifdef SQLITE_UNIX_THREADS
  pthread_t tid;            /* The thread authorized to use this OsFile */
#endif
};


/*
** Do not include any of the File I/O interface procedures if the
** SQLITE_OMIT_DISKIO macro is defined (indicating that there database
** will be in-memory only)
*/
#ifndef SQLITE_OMIT_DISKIO
................................................................................
** same thread is operating on the OsFile.  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.  This logic makes sure a user does not try to do that
** by mistake.
*/
#if defined(SQLITE_UNIX_THREADS) && !defined(SQLITE_ALLOW_XTHREAD_CONNECTIONS)
# define SET_THREADID(X)   (X)->tid = pthread_self()
# define CHECK_THREADID(X) (!pthread_equal((X)->tid, pthread_self()))
#else
# define SET_THREADID(X)
# define CHECK_THREADID(X) 0
#endif

/*
** Here is the dirt on POSIX advisory locks:  ANSI STD 1003.1 (1996)
................................................................................

/*
** Return TRUE if the named file exists.
*/
static int unixFileExists(const char *zFilename){
  return access(zFilename, 0)==0;
}

/*
** Allocate memory for an OsFile.  Initialize the new OsFile
** to the value given in pInit and return a pointer to the new
** OsFile.  If we run out of memory, close the file and return NULL.
*/
static OsFile *allocateOsFile(OsFile *pInit){
  OsFile *pNew;
  pNew = sqliteMalloc( sizeof(OsFile) );
  if( pNew==0 ){
    close(pInit->h);
  }else{
    *pNew = *pInit;
  }
  return pNew;
}

/*
** Attempt to open a file for both reading and writing.  If that
** fails, try opening it read-only.  If the file does not exist,
** try to create it.
**
** On success, a handle for the open file is written to *id
................................................................................
** SQLITE_OK.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id and *pReadonly unchanged.
*/
static int unixOpenReadWrite(
  const char *zFilename,
  OsFile **pId,
  int *pReadonly
){
  int rc;
  OsFile f;

  assert( 0==*pId );
  f.dirfd = -1;
  SET_THREADID(&f);
  f.h = open(zFilename, O_RDWR|O_CREAT|O_LARGEFILE|O_BINARY,
                          SQLITE_DEFAULT_FILE_PERMISSIONS);
  if( f.h<0 ){
#ifdef EISDIR
    if( errno==EISDIR ){
      return SQLITE_CANTOPEN;
    }
#endif
    f.h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
    if( f.h<0 ){
      return SQLITE_CANTOPEN; 
    }
    *pReadonly = 1;
  }else{
    *pReadonly = 0;
  }
  sqlite3OsEnterMutex();
  rc = findLockInfo(f.h, &f.pLock, &f.pOpen);
  sqlite3OsLeaveMutex();
  if( rc ){
    close(f.h);
    return SQLITE_NOMEM;
  }
  f.locktype = 0;

  TRACE3("OPEN    %-3d %s\n", f.h, zFilename);
  *pId = allocateOsFile(&f);
  if( *pId==0 ){
    return SQLITE_NOMEM;
  }else{
    OpenCounter(+1);
    return SQLITE_OK;
  }
}


/*
** Attempt to open a new file for exclusive access by this process.
** The file will be opened for both reading and writing.  To avoid
** a potential security problem, we do not allow the file to have
................................................................................
** If delFlag is true, then make arrangements to automatically delete
** the file when it is closed.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int unixOpenExclusive(const char *zFilename, OsFile **pId, int delFlag){
  int rc;
  OsFile f;

  assert( 0==*pId );
  if( access(zFilename, 0)==0 ){
    return SQLITE_CANTOPEN;
  }
  SET_THREADID(&f);
  f.dirfd = -1;
  f.h = open(zFilename,
                O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW|O_LARGEFILE|O_BINARY,
                SQLITE_DEFAULT_FILE_PERMISSIONS);
  if( f.h<0 ){
    return SQLITE_CANTOPEN;
  }
  sqlite3OsEnterMutex();
  rc = findLockInfo(f.h, &f.pLock, &f.pOpen);
  sqlite3OsLeaveMutex();
  if( rc ){
    close(f.h);
    unlink(zFilename);
    return SQLITE_NOMEM;
  }
  f.locktype = 0;

  if( delFlag ){
    unlink(zFilename);
  }
  TRACE3("OPEN-EX %-3d %s\n", f.h, zFilename);
  *pId = allocateOsFile(&f);
  if( *pId==0 ){
    return SQLITE_NOMEM;
  }else{
    OpenCounter(+1);
    return SQLITE_OK;
  }
}

/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int unixOpenReadOnly(const char *zFilename, OsFile **pId){
  int rc;
  OsFile f;

  assert( 0==*pId );
  SET_THREADID(&f);
  f.dirfd = -1;
  f.h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
  if( f.h<0 ){
    return SQLITE_CANTOPEN;
  }
  sqlite3OsEnterMutex();
  rc = findLockInfo(f.h, &f.pLock, &f.pOpen);
  sqlite3OsLeaveMutex();
  if( rc ){
    close(f.h);
    return SQLITE_NOMEM;
  }
  f.locktype = 0;

  TRACE3("OPEN-RO %-3d %s\n", f.h, zFilename);
  *pId = allocateOsFile(&f);
  if( *pId==0 ){
    return SQLITE_NOMEM;
  }else{
    OpenCounter(+1);
    return SQLITE_OK;
  }
}

/*
** Attempt to open a file descriptor for the directory that contains a
** file.  This file descriptor can be used to fsync() the directory
** in order to make sure the creation of a new file is actually written
** to disk.
**
** This routine is only meaningful for Unix.  It is a no-op under
** windows since windows does not support hard links.
**
** On success, a handle for a previously open file at *id is
** updated with the new directory file descriptor and SQLITE_OK is
** returned.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id unchanged.
*/
static int unixOpenDirectory(
  const char *zDirname,
  OsFile *id
){
  if( id==0 ){
    /* Do not open the directory if the corresponding file is not already
    ** open. */
    return SQLITE_CANTOPEN;
  }
  SET_THREADID(id);
  assert( id->dirfd<0 );
  id->dirfd = open(zDirname, O_RDONLY|O_BINARY, 0);
................................................................................
/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
static int unixRead(OsFile *id, void *pBuf, int amt){
  int got;
  assert( id );
  SimulateIOError(SQLITE_IOERR);
  TIMER_START;
  got = read(id->h, pBuf, amt);
  TIMER_END;
  TRACE5("READ    %-3d %5d %7d %d\n", id->h, got, last_page, TIMER_ELAPSED);
  SEEK(0);
  /* if( got<0 ) got = 0; */
................................................................................

/*
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
*/
static int unixWrite(OsFile *id, const void *pBuf, int amt){
  int wrote = 0;
  assert( id );
  assert( amt>0 );
  SimulateIOError(SQLITE_IOERR);
  SimulateDiskfullError;
  TIMER_START;
  while( amt>0 && (wrote = write(id->h, pBuf, amt))>0 ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
................................................................................
  return SQLITE_OK;
}

/*
** Move the read/write pointer in a file.
*/
static int unixSeek(OsFile *id, i64 offset){
  assert( id );
  SEEK(offset/1024 + 1);
#ifdef SQLITE_TEST
  if( offset ) SimulateDiskfullError
#endif
  lseek(id->h, offset, SEEK_SET);
  return SQLITE_OK;
}
................................................................................
** If we do not do this and we encounter a power failure, the directory
** entry for the journal might not exist after we reboot.  The next
** SQLite to access the file will not know that the journal exists (because
** the directory entry for the journal was never created) and the transaction
** will not roll back - possibly leading to database corruption.
*/
static int unixSync(OsFile *id, int dataOnly){
  assert( id );
  SimulateIOError(SQLITE_IOERR);
  TRACE2("SYNC    %-3d\n", id->h);
  if( full_fsync(id->h, id->fullSync, dataOnly) ){
    return SQLITE_IOERR;
  }
  if( id->dirfd>=0 ){
    TRACE2("DIRSYNC %-3d\n", id->dirfd);
................................................................................
#endif
}

/*
** Truncate an open file to a specified size
*/
static int unixTruncate(OsFile *id, i64 nByte){
  assert( id );
  SimulateIOError(SQLITE_IOERR);
  return ftruncate(id->h, nByte)==0 ? SQLITE_OK : SQLITE_IOERR;
}

/*
** Determine the current size of a file in bytes
*/
static int unixFileSize(OsFile *id, i64 *pSize){
  struct stat buf;
  assert( id );
  SimulateIOError(SQLITE_IOERR);
  if( fstat(id->h, &buf)!=0 ){
    return SQLITE_IOERR;
  }
  *pSize = buf.st_size;
  return SQLITE_OK;
}
................................................................................
** file by this or any other process. If such a lock is held, return
** non-zero.  If the file is unlocked or holds only SHARED locks, then
** return zero.
*/
static int unixCheckReservedLock(OsFile *id){
  int r = 0;

  assert( id );
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;
  sqlite3OsEnterMutex(); /* Needed because id->pLock is shared across threads */

  /* Check if a thread in this process holds such a lock */
  if( id->pLock->locktype>SHARED_LOCK ){
    r = 1;
  }
................................................................................
  ** even if the locking primitive used is always a write-lock.
  */
  int rc = SQLITE_OK;
  struct lockInfo *pLock = id->pLock;
  struct flock lock;
  int s;

  assert( id );
  TRACE7("LOCK    %d %s was %s(%s,%d) pid=%d\n", id->h, locktypeName(locktype), 
      locktypeName(id->locktype), locktypeName(pLock->locktype), pLock->cnt
      ,getpid() );
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as
................................................................................
** might return SQLITE_IOERR instead of SQLITE_OK.
*/
static int unixUnlock(OsFile *id, int locktype){
  struct lockInfo *pLock;
  struct flock lock;
  int rc = SQLITE_OK;

  assert( id );
  TRACE7("UNLOCK  %d %d was %d(%d,%d) pid=%d\n", id->h, locktype, id->locktype, 
      id->pLock->locktype, id->pLock->cnt, getpid());
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;

  assert( locktype<=SHARED_LOCK );
  if( id->locktype<=locktype ){
    return SQLITE_OK;
................................................................................
  id->locktype = locktype;
  return rc;
}

/*
** Close a file.
*/
static int unixClose(OsFile **pId){
  OsFile *id = *pId;
  if( !id ) return SQLITE_OK;
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;
  sqlite3Io.xUnlock(id, NO_LOCK);
  if( id->dirfd>=0 ) close(id->dirfd);
  id->dirfd = -1;
  sqlite3OsEnterMutex();
  if( id->pOpen->nLock ){
    /* If there are outstanding locks, do not actually close the file just
................................................................................
  }
  releaseLockInfo(id->pLock);
  releaseOpenCnt(id->pOpen);
  sqlite3OsLeaveMutex();
  id->isOpen = 0;
  TRACE2("CLOSE   %-3d\n", id->h);
  OpenCounter(-1);
  sqliteFree(id);
  *pId = 0;
  return SQLITE_OK;
}

/*
** Turn a relative pathname into a full pathname.  Return a pointer
** to the full pathname stored in space obtained from sqliteMalloc().
** The calling function is responsible for freeing this space once it
................................................................................
                    (char*)0);
    sqliteFree(zBuf);
  }
  return zFull;
}

/*
** Change the value of the fullsync flag in the given file descriptor.
*/
static void unixSetFullSync(OsFile *id, int v){
  id->fullSync = v;
}

/*
** Return the underlying file handle for an OsFile
*/
static int unixFileHandle(OsFile *id){
  return id->h;
}

/*
** Return an integer that indices the type of lock currently held
** by this handle.  (Used for testing and analysis only.)
*/
static int unixLockState(OsFile *id){
  return id->locktype;
}

/*
** This is the structure that defines all of the I/O routines.
*/
struct sqlite3IoVtbl sqlite3Io = {
  unixDelete,
................................................................................
  unixSync,
  unixTruncate,
  unixFileSize,
  unixFullPathname,
  unixLock,
  unixUnlock,
  unixCheckReservedLock,
  unixSetFullSync,
  unixFileHandle,
  unixLockState,
};


#endif /* SQLITE_OMIT_DISKIO */
/***************************************************************************
** Everything above deals with file I/O.  Everything that follows deals
** with other miscellanous aspects of the operating system interface

Changes to src/os_win.c.

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**
** This file contains code that is specific to windows.
*/
#include "sqliteInt.h"
#include "os.h"
#if OS_WIN               /* This file is used for windows only */


#include <winbase.h>

#ifdef __CYGWIN__
# include <sys/cygwin.h>
#endif

/*
................................................................................
# define SQLITE_W32_THREADS 1
#endif

/*
** Include code that is common to all os_*.c files
*/
#include "os_common.h"















/*
** Do not include any of the File I/O interface procedures if the
** SQLITE_OMIT_DISKIO macro is defined (indicating that there database
** will be in-memory only)
*/
#ifndef SQLITE_OMIT_DISKIO
................................................................................
    sqliteFree(zWide);
  }else{
    exists = GetFileAttributesA(zFilename) != 0xffffffff;
  }
  return exists;
}


















/*
** Attempt to open a file for both reading and writing.  If that
** fails, try opening it read-only.  If the file does not exist,
** try to create it.
**
** On success, a handle for the open file is written to *id
** and *pReadonly is set to 0 if the file was opened for reading and
................................................................................
** SQLITE_OK.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id and *pReadonly unchanged.
*/
static int winOpenReadWrite(
  const char *zFilename,
  OsFile *id,
  int *pReadonly
){

  HANDLE h;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( !id->isOpen );
  if( zWide ){
    h = CreateFileW(zWide,
       GENERIC_READ | GENERIC_WRITE,
       FILE_SHARE_READ | FILE_SHARE_WRITE,
       NULL,
       OPEN_ALWAYS,
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
................................................................................
        return SQLITE_CANTOPEN;
      }
      *pReadonly = 1;
    }else{
      *pReadonly = 0;
    }
  }
  id->h = h;
  id->locktype = NO_LOCK;
  id->sharedLockByte = 0;
  id->isOpen = 1;




  OpenCounter(+1);
  TRACE3("OPEN R/W %d \"%s\"\n", h, zFilename);
  return SQLITE_OK;

}


/*
** Attempt to open a new file for exclusive access by this process.
** The file will be opened for both reading and writing.  To avoid
** a potential security problem, we do not allow the file to have
................................................................................
** If delFlag is true, then make arrangements to automatically delete
** the file when it is closed.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int winOpenExclusive(const char *zFilename, OsFile *id, int delFlag){

  HANDLE h;
  int fileflags;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( !id->isOpen );
  if( delFlag ){
    fileflags = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_RANDOM_ACCESS 
                     | FILE_FLAG_DELETE_ON_CLOSE;
  }else{
    fileflags = FILE_FLAG_RANDOM_ACCESS;
  }
  if( zWide ){
................................................................................
       fileflags,
       NULL
    );
  }
  if( h==INVALID_HANDLE_VALUE ){
    return SQLITE_CANTOPEN;
  }
  id->h = h;
  id->locktype = NO_LOCK;
  id->sharedLockByte = 0;
  id->isOpen = 1;




  OpenCounter(+1);
  TRACE3("OPEN EX %d \"%s\"\n", h, zFilename);
  return SQLITE_OK;

}

/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int winOpenReadOnly(const char *zFilename, OsFile *id){

  HANDLE h;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( !id->isOpen );
  if( zWide ){
    h = CreateFileW(zWide,
       GENERIC_READ,
       0,
       NULL,
       OPEN_EXISTING,
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
................................................................................
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
       NULL
    );
  }
  if( h==INVALID_HANDLE_VALUE ){
    return SQLITE_CANTOPEN;
  }
  id->h = h;
  id->locktype = NO_LOCK;
  id->sharedLockByte = 0;
  id->isOpen = 1;




  OpenCounter(+1);
  TRACE3("OPEN RO %d \"%s\"\n", h, zFilename);
  return SQLITE_OK;

}

/*
** Attempt to open a file descriptor for the directory that contains a
** file.  This file descriptor can be used to fsync() the directory
** in order to make sure the creation of a new file is actually written
** to disk.
................................................................................
  TRACE2("TEMP FILENAME: %s\n", zBuf);
  return SQLITE_OK; 
}

/*
** Close a file.
*/
static int winClose(OsFile *id){
  if( id->isOpen ){
    TRACE2("CLOSE %d\n", id->h);
    CloseHandle(id->h);
    OpenCounter(-1);

    id->isOpen = 0;
  }
  return SQLITE_OK;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
static int winRead(OsFile *id, void *pBuf, int amt){
  DWORD got;
  assert( id->isOpen );
  SimulateIOError(SQLITE_IOERR);
  TRACE3("READ %d lock=%d\n", id->h, id->locktype);
  if( !ReadFile(id->h, pBuf, amt, &got, 0) ){
    got = 0;
  }
  if( got==(DWORD)amt ){
    return SQLITE_OK;
................................................................................
/*
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
*/
static int winWrite(OsFile *id, const void *pBuf, int amt){
  int rc = 0;
  DWORD wrote;
  assert( id->isOpen );
  SimulateIOError(SQLITE_IOERR);
  SimulateDiskfullError;
  TRACE3("WRITE %d lock=%d\n", id->h, id->locktype);
  assert( amt>0 );
  while( amt>0 && (rc = WriteFile(id->h, pBuf, amt, &wrote, 0))!=0 && wrote>0 ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
................................................................................
/*
** Move the read/write pointer in a file.
*/
static int winSeek(OsFile *id, i64 offset){
  LONG upperBits = offset>>32;
  LONG lowerBits = offset & 0xffffffff;
  DWORD rc;
  assert( id->isOpen );
#ifdef SQLITE_TEST
  if( offset ) SimulateDiskfullError
#endif
  SEEK(offset/1024 + 1);
  rc = SetFilePointer(id->h, lowerBits, &upperBits, FILE_BEGIN);
  TRACE3("SEEK %d %lld\n", id->h, offset);
  if( rc==INVALID_SET_FILE_POINTER && GetLastError()!=NO_ERROR ){
................................................................................
  return SQLITE_OK;
}

/*
** Make sure all writes to a particular file are committed to disk.
*/
static int winSync(OsFile *id, int dataOnly){
  assert( id->isOpen );
  TRACE3("SYNC %d lock=%d\n", id->h, id->locktype);
  if( FlushFileBuffers(id->h) ){
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR;
  }
}
................................................................................
}

/*
** Truncate an open file to a specified size
*/
static int winTruncate(OsFile *id, i64 nByte){
  LONG upperBits = nByte>>32;
  assert( id->isOpen );
  TRACE3("TRUNCATE %d %lld\n", id->h, nByte);
  SimulateIOError(SQLITE_IOERR);
  SetFilePointer(id->h, nByte, &upperBits, FILE_BEGIN);
  SetEndOfFile(id->h);
  return SQLITE_OK;
}

/*
** Determine the current size of a file in bytes
*/
static int winFileSize(OsFile *id, i64 *pSize){
  DWORD upperBits, lowerBits;
  assert( id->isOpen );
  SimulateIOError(SQLITE_IOERR);
  lowerBits = GetFileSize(id->h, &upperBits);
  *pSize = (((i64)upperBits)<<32) + lowerBits;
  return SQLITE_OK;
}

/*
................................................................................
*/
static int winLock(OsFile *id, int locktype){
  int rc = SQLITE_OK;    /* Return code from subroutines */
  int res = 1;           /* Result of a windows lock call */
  int newLocktype;       /* Set id->locktype to this value before exiting */
  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */

  assert( id->isOpen );
  TRACE5("LOCK %d %d was %d(%d)\n",
          id->h, locktype, id->locktype, id->sharedLockByte);

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3OsEnterMutex() hasn't been called yet.
  */
................................................................................
/*
** 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(OsFile *id){
  int rc;
  assert( id->isOpen );
  if( id->locktype>=RESERVED_LOCK ){
    rc = 1;
    TRACE3("TEST WR-LOCK %d %d (local)\n", id->h, rc);
  }else{
    rc = LockFile(id->h, RESERVED_BYTE, 0, 1, 0);
    if( rc ){
      UnlockFile(id->h, RESERVED_BYTE, 0, 1, 0);
................................................................................
** It is not possible for this routine to fail if the second argument
** is NO_LOCK.  If the second argument is SHARED_LOCK then this routine
** might return SQLITE_IOERR;
*/
static int winUnlock(OsFile *id, int locktype){
  int type;
  int rc = SQLITE_OK;
  assert( id->isOpen );
  assert( locktype<=SHARED_LOCK );
  TRACE5("UNLOCK %d to %d was %d(%d)\n", id->h, locktype,
          id->locktype, id->sharedLockByte);
  type = id->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    UnlockFile(id->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( locktype==SHARED_LOCK && !getReadLock(id) ){
................................................................................
    GetFullPathNameA(zRelative, nByte, zFull, &zNotUsed);
  }
#endif
  return zFull;
}

/*
** Make a copy of an OsFile object.
*/
static void winCopyOsFile(OsFile *pDest, OsFile *pSrc){
  *pDest = *pSrc;















}


/*
** This is the structure that defines all of the I/O routines.
*/
struct sqlite3IoVtbl sqlite3Io = {
................................................................................
  winSync,
  winTruncate,
  winFileSize,
  winFullPathname,
  winLock,
  winUnlock,
  winCheckReservedLock,
  winCopyOsFile,


};

#endif /* SQLITE_OMIT_DISKIO */
/***************************************************************************
** Everything above deals with file I/O.  Everything that follows deals
** with other miscellanous aspects of the operating system interface
****************************************************************************/







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**
** This file contains code that is specific to windows.
*/
#include "sqliteInt.h"
#include "os.h"
#if OS_WIN               /* This file is used for windows only */

#include <windows.h>
#include <winbase.h>

#ifdef __CYGWIN__
# include <sys/cygwin.h>
#endif

/*
................................................................................
# define SQLITE_W32_THREADS 1
#endif

/*
** Include code that is common to all os_*.c files
*/
#include "os_common.h"

/*
** The OsFile structure is a operating-system independing representation
** of an open file handle.  It is defined differently for each architecture.
**
** This is the definition for Win32.
*/
struct OsFile {
  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 */
};



/*
** Do not include any of the File I/O interface procedures if the
** SQLITE_OMIT_DISKIO macro is defined (indicating that there database
** will be in-memory only)
*/
#ifndef SQLITE_OMIT_DISKIO
................................................................................
    sqliteFree(zWide);
  }else{
    exists = GetFileAttributesA(zFilename) != 0xffffffff;
  }
  return exists;
}


/*
** Allocate memory for an OsFile.  Initialize the new OsFile
** to the value given in pInit and return a pointer to the new
** OsFile.  If we run out of memory, close the file and return NULL.
*/
static OsFile *allocateOsFile(OsFile *pInit){
  OsFile *pNew;
  pNew = sqliteMalloc( sizeof(OsFile) );
  if( pNew==0 ){
    CloseHandle(pInit->h);
  }else{
    *pNew = *pInit;
  }
  return pNew;
}

/*
** Attempt to open a file for both reading and writing.  If that
** fails, try opening it read-only.  If the file does not exist,
** try to create it.
**
** On success, a handle for the open file is written to *id
** and *pReadonly is set to 0 if the file was opened for reading and
................................................................................
** SQLITE_OK.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id and *pReadonly unchanged.
*/
static int winOpenReadWrite(
  const char *zFilename,
  OsFile **pId,
  int *pReadonly
){
  OsFile f;
  HANDLE h;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( *pId==0 );
  if( zWide ){
    h = CreateFileW(zWide,
       GENERIC_READ | GENERIC_WRITE,
       FILE_SHARE_READ | FILE_SHARE_WRITE,
       NULL,
       OPEN_ALWAYS,
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
................................................................................
        return SQLITE_CANTOPEN;
      }
      *pReadonly = 1;
    }else{
      *pReadonly = 0;
    }
  }
  f.h = h;
  f.locktype = NO_LOCK;
  f.sharedLockByte = 0;
  TRACE3("OPEN R/W %d \"%s\"\n", h, zFilename);
  *pId = allocateOsFile(&f);
  if( *pId==0 ){
    return SQLITE_NOMEM;
  }else{
    OpenCounter(+1);

    return SQLITE_OK;
  }
}


/*
** Attempt to open a new file for exclusive access by this process.
** The file will be opened for both reading and writing.  To avoid
** a potential security problem, we do not allow the file to have
................................................................................
** If delFlag is true, then make arrangements to automatically delete
** the file when it is closed.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int winOpenExclusive(const char *zFilename, OsFile **pId, int delFlag){
  OsFile f;
  HANDLE h;
  int fileflags;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( *pId == 0 );
  if( delFlag ){
    fileflags = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_RANDOM_ACCESS 
                     | FILE_FLAG_DELETE_ON_CLOSE;
  }else{
    fileflags = FILE_FLAG_RANDOM_ACCESS;
  }
  if( zWide ){
................................................................................
       fileflags,
       NULL
    );
  }
  if( h==INVALID_HANDLE_VALUE ){
    return SQLITE_CANTOPEN;
  }
  f.h = h;
  f.locktype = NO_LOCK;
  f.sharedLockByte = 0;
  TRACE3("OPEN EX %d \"%s\"\n", h, zFilename);
  *pId = allocateOsFile(&f);
  if( *pId==0 ){
    return SQLITE_NOMEM;
  }else{
    OpenCounter(+1);

    return SQLITE_OK;
  }
}

/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
static int winOpenReadOnly(const char *zFilename, OsFile **pId){
  OsFile f;
  HANDLE h;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( *pId==0 );
  if( zWide ){
    h = CreateFileW(zWide,
       GENERIC_READ,
       0,
       NULL,
       OPEN_EXISTING,
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
................................................................................
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
       NULL
    );
  }
  if( h==INVALID_HANDLE_VALUE ){
    return SQLITE_CANTOPEN;
  }
  f.h = h;
  f.locktype = NO_LOCK;
  f.sharedLockByte = 0;
  TRACE3("OPEN RO %d \"%s\"\n", h, zFilename);
  *pId = allocateOsFile(&f);
  if( *pId==0 ){
    return SQLITE_NOMEM;
  }else{
    OpenCounter(+1);

    return SQLITE_OK;
  }
}

/*
** Attempt to open a file descriptor for the directory that contains a
** file.  This file descriptor can be used to fsync() the directory
** in order to make sure the creation of a new file is actually written
** to disk.
................................................................................
  TRACE2("TEMP FILENAME: %s\n", zBuf);
  return SQLITE_OK; 
}

/*
** Close a file.
*/
static int winClose(OsFile **pId){
  if( *pId ){
    TRACE2("CLOSE %d\n", (*pId)->h);
    CloseHandle((*pId)->h);
    OpenCounter(-1);
    sqliteFree(*pId);
    *pId = 0;
  }
  return SQLITE_OK;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
static int winRead(OsFile *id, void *pBuf, int amt){
  DWORD got;
  assert( id!=0 );
  SimulateIOError(SQLITE_IOERR);
  TRACE3("READ %d lock=%d\n", id->h, id->locktype);
  if( !ReadFile(id->h, pBuf, amt, &got, 0) ){
    got = 0;
  }
  if( got==(DWORD)amt ){
    return SQLITE_OK;
................................................................................
/*
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
*/
static int winWrite(OsFile *id, const void *pBuf, int amt){
  int rc = 0;
  DWORD wrote;
  assert( id!=0 );
  SimulateIOError(SQLITE_IOERR);
  SimulateDiskfullError;
  TRACE3("WRITE %d lock=%d\n", id->h, id->locktype);
  assert( amt>0 );
  while( amt>0 && (rc = WriteFile(id->h, pBuf, amt, &wrote, 0))!=0 && wrote>0 ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
................................................................................
/*
** Move the read/write pointer in a file.
*/
static int winSeek(OsFile *id, i64 offset){
  LONG upperBits = offset>>32;
  LONG lowerBits = offset & 0xffffffff;
  DWORD rc;
  assert( id!=0 );
#ifdef SQLITE_TEST
  if( offset ) SimulateDiskfullError
#endif
  SEEK(offset/1024 + 1);
  rc = SetFilePointer(id->h, lowerBits, &upperBits, FILE_BEGIN);
  TRACE3("SEEK %d %lld\n", id->h, offset);
  if( rc==INVALID_SET_FILE_POINTER && GetLastError()!=NO_ERROR ){
................................................................................
  return SQLITE_OK;
}

/*
** Make sure all writes to a particular file are committed to disk.
*/
static int winSync(OsFile *id, int dataOnly){
  assert( id!=0 );
  TRACE3("SYNC %d lock=%d\n", id->h, id->locktype);
  if( FlushFileBuffers(id->h) ){
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR;
  }
}
................................................................................
}

/*
** Truncate an open file to a specified size
*/
static int winTruncate(OsFile *id, i64 nByte){
  LONG upperBits = nByte>>32;
  assert( id!=0 );
  TRACE3("TRUNCATE %d %lld\n", id->h, nByte);
  SimulateIOError(SQLITE_IOERR);
  SetFilePointer(id->h, nByte, &upperBits, FILE_BEGIN);
  SetEndOfFile(id->h);
  return SQLITE_OK;
}

/*
** Determine the current size of a file in bytes
*/
static int winFileSize(OsFile *id, i64 *pSize){
  DWORD upperBits, lowerBits;
  assert( id!=0 );
  SimulateIOError(SQLITE_IOERR);
  lowerBits = GetFileSize(id->h, &upperBits);
  *pSize = (((i64)upperBits)<<32) + lowerBits;
  return SQLITE_OK;
}

/*
................................................................................
*/
static int winLock(OsFile *id, int locktype){
  int rc = SQLITE_OK;    /* Return code from subroutines */
  int res = 1;           /* Result of a windows lock call */
  int newLocktype;       /* Set id->locktype to this value before exiting */
  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */

  assert( id!=0 );
  TRACE5("LOCK %d %d was %d(%d)\n",
          id->h, locktype, id->locktype, id->sharedLockByte);

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3OsEnterMutex() hasn't been called yet.
  */
................................................................................
/*
** 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(OsFile *id){
  int rc;
  assert( id!=0 );
  if( id->locktype>=RESERVED_LOCK ){
    rc = 1;
    TRACE3("TEST WR-LOCK %d %d (local)\n", id->h, rc);
  }else{
    rc = LockFile(id->h, RESERVED_BYTE, 0, 1, 0);
    if( rc ){
      UnlockFile(id->h, RESERVED_BYTE, 0, 1, 0);
................................................................................
** It is not possible for this routine to fail if the second argument
** is NO_LOCK.  If the second argument is SHARED_LOCK then this routine
** might return SQLITE_IOERR;
*/
static int winUnlock(OsFile *id, int locktype){
  int type;
  int rc = SQLITE_OK;
  assert( id!=0 );
  assert( locktype<=SHARED_LOCK );
  TRACE5("UNLOCK %d to %d was %d(%d)\n", id->h, locktype,
          id->locktype, id->sharedLockByte);
  type = id->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    UnlockFile(id->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( locktype==SHARED_LOCK && !getReadLock(id) ){
................................................................................
    GetFullPathNameA(zRelative, nByte, zFull, &zNotUsed);
  }
#endif
  return zFull;
}

/*
** The fullSync option is meaningless on windows.   This is a no-op.
*/
static void winSetFullSync(OsFile *id, int v){
  return;
}

/*
** Return the underlying file handle for an OsFile
*/
static int winFileHandle(OsFile *id){
  return (int)id->h;
}

/*
** Return an integer that indices the type of lock currently held
** by this handle.  (Used for testing and analysis only.)
*/
static int winLockState(OsFile *id){
  return id->locktype;
}


/*
** This is the structure that defines all of the I/O routines.
*/
struct sqlite3IoVtbl sqlite3Io = {
................................................................................
  winSync,
  winTruncate,
  winFileSize,
  winFullPathname,
  winLock,
  winUnlock,
  winCheckReservedLock,
  winSetFullSync,
  winFileHandle,
  winLockState,
};

#endif /* SQLITE_OMIT_DISKIO */
/***************************************************************************
** Everything above deals with file I/O.  Everything that follows deals
** with other miscellanous aspects of the operating system interface
****************************************************************************/

Changes to src/pager.c.

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** 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 1.220 2005/11/26 03:51:19 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>
................................................................................
** The following two macros are used within the TRACEX() macros above
** to print out file-descriptors. 
**
** PAGERID() takes a pointer to a Pager struct as it's argument. The
** associated file-descriptor is returned. FILEHANDLEID() takes an OsFile
** struct as it's argument.
*/
#define PAGERID(p) (p->fd.h)
#define FILEHANDLEID(fd) (fd.h)

/*
** The page cache as a whole is always in one of the following
** states:
**
**   PAGER_UNLOCK        The page cache is not currently reading or 
**                       writing the database file.  There is no
................................................................................
  int nRef;                   /* Number of in-memory pages with PgHdr.nRef>0 */
  int mxPage;                 /* Maximum number of pages to hold in cache */
  u8 *aInJournal;             /* One bit for each page in the database file */
  u8 *aInStmt;                /* One bit for each page in the database */
  char *zFilename;            /* Name of the database file */
  char *zJournal;             /* Name of the journal file */
  char *zDirectory;           /* Directory hold database and journal files */
  OsFile fd, jfd;             /* File descriptors for database and journal */
  OsFile stfd;                /* File descriptor for the statement subjournal*/
  BusyHandler *pBusyHandler;  /* Pointer to sqlite.busyHandler */
  PgHdr *pFirst, *pLast;      /* List of free pages */
  PgHdr *pFirstSynced;        /* First free page with PgHdr.needSync==0 */
  PgHdr *pAll;                /* List of all pages */
  PgHdr *pStmt;               /* List of pages in the statement subjournal */
  i64 journalOff;             /* Current byte offset in the journal file */
  i64 journalHdr;             /* Byte offset to previous journal header */
................................................................................
  if( c ){
    offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager);
  }
  assert( offset%JOURNAL_HDR_SZ(pPager)==0 );
  assert( offset>=c );
  assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
  pPager->journalOff = offset;
  return sqlite3Io.xSeek(&pPager->jfd, pPager->journalOff);
}

/*
** The journal file must be open when this routine is called. A journal
** header (JOURNAL_HDR_SZ bytes) is written into the journal file at the
** current location.
**
................................................................................
  **
  ** Possibly for a pager not in no-sync mode, the journal magic should not
  ** be written until nRec is filled in as part of next syncJournal(). 
  **
  ** Actually maybe the whole journal header should be delayed until that
  ** point. Think about this.
  */
  rc = sqlite3Io.xWrite(&pPager->jfd, aJournalMagic, sizeof(aJournalMagic));

  if( rc==SQLITE_OK ){
    /* The nRec Field. 0xFFFFFFFF for no-sync journals. */
    rc = write32bits(&pPager->jfd, pPager->noSync ? 0xffffffff : 0);
  }
  if( rc==SQLITE_OK ){
    /* The random check-hash initialiser */ 
    sqlite3Randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
    rc = write32bits(&pPager->jfd, pPager->cksumInit);
  }
  if( rc==SQLITE_OK ){
    /* The initial database size */
    rc = write32bits(&pPager->jfd, pPager->dbSize);
  }
  if( rc==SQLITE_OK ){
    /* The assumed sector size for this process */
    rc = write32bits(&pPager->jfd, pPager->sectorSize);
  }

  /* The journal header has been written successfully. Seek the journal
  ** file descriptor to the end of the journal header sector.
  */
  if( rc==SQLITE_OK ){
    rc = sqlite3Io.xSeek(&pPager->jfd, pPager->journalOff-1);
    if( rc==SQLITE_OK ){
      rc = sqlite3Io.xWrite(&pPager->jfd, "\000", 1);
    }
  }
  return rc;
}

/*
** The journal file must be open when this is called. A journal header file
................................................................................
  rc = seekJournalHdr(pPager);
  if( rc ) return rc;

  if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
    return SQLITE_DONE;
  }

  rc = sqlite3Io.xRead(&pPager->jfd, aMagic, sizeof(aMagic));
  if( rc ) return rc;

  if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
    return SQLITE_DONE;
  }

  rc = read32bits(&pPager->jfd, pNRec);
  if( rc ) return rc;

  rc = read32bits(&pPager->jfd, &pPager->cksumInit);
  if( rc ) return rc;

  rc = read32bits(&pPager->jfd, pDbSize);
  if( rc ) return rc;

  /* Update the assumed sector-size to match the value used by 
  ** the process that created this journal. If this journal was
  ** created by a process other than this one, then this routine
  ** is being called from within pager_playback(). The local value
  ** of Pager.sectorSize is restored at the end of that routine.
  */
  rc = read32bits(&pPager->jfd, (u32 *)&pPager->sectorSize);
  if( rc ) return rc;

  pPager->journalOff += JOURNAL_HDR_SZ(pPager);
  rc = sqlite3Io.xSeek(&pPager->jfd, pPager->journalOff);
  return rc;
}


/*
** Write the supplied master journal name into the journal file for pager
** pPager at the current location. The master journal name must be the last
................................................................................
  */
  if( pPager->fullSync ){
    rc = seekJournalHdr(pPager);
    if( rc!=SQLITE_OK ) return rc;
  }
  pPager->journalOff += (len+20);

  rc = write32bits(&pPager->jfd, PAGER_MJ_PGNO(pPager));
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3Io.xWrite(&pPager->jfd, zMaster, len);
  if( rc!=SQLITE_OK ) return rc;

  rc = write32bits(&pPager->jfd, len);
  if( rc!=SQLITE_OK ) return rc;

  rc = write32bits(&pPager->jfd, cksum);
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3Io.xWrite(&pPager->jfd, aJournalMagic, sizeof(aJournalMagic));
  pPager->needSync = !pPager->noSync;
  return rc;
}

/*
** Add or remove a page from the list of all pages that are in the
** statement journal.
................................................................................
  pPager->pLast = 0;
  pPager->pAll = 0;
  memset(pPager->aHash, 0, sizeof(pPager->aHash));
  pPager->nPage = 0;
  if( pPager->state>=PAGER_RESERVED ){
    sqlite3pager_rollback(pPager);
  }
  sqlite3Io.xUnlock(&pPager->fd, NO_LOCK);
  pPager->state = PAGER_UNLOCK;
  pPager->dbSize = -1;
  pPager->nRef = 0;
  assert( pPager->journalOpen==0 );
}

/*
................................................................................
    }
    pPager->dirtyCache = 0;
    pPager->nRec = 0;
  }else{
    assert( pPager->aInJournal==0 );
    assert( pPager->dirtyCache==0 || pPager->useJournal==0 );
  }
  rc = sqlite3Io.xUnlock(&pPager->fd, SHARED_LOCK);
  pPager->state = PAGER_SHARED;
  pPager->origDbSize = 0;
  pPager->setMaster = 0;
  return rc;
}

/*
................................................................................
  Pgno pgno;                    /* The page number of a page in journal */
  u32 cksum;                    /* Checksum used for sanity checking */
  u8 aData[SQLITE_MAX_PAGE_SIZE];  /* Temp storage for a page */

  /* useCksum should be true for the main journal and false for
  ** statement journals.  Verify that this is always the case
  */
  assert( jfd == (useCksum ? &pPager->jfd : &pPager->stfd) );


  rc = read32bits(jfd, &pgno);
  if( rc!=SQLITE_OK ) return rc;
  rc = sqlite3Io.xRead(jfd, &aData, pPager->pageSize);
  if( rc!=SQLITE_OK ) return rc;
  pPager->journalOff += pPager->pageSize + 4;
................................................................................
  ** page content is in the main journal either because the page is not in
  ** cache or else it is marked as needSync==0.
  */
  pPg = pager_lookup(pPager, pgno);
  assert( pPager->state>=PAGER_EXCLUSIVE || pPg!=0 );
  TRACE3("PLAYBACK %d page %d\n", PAGERID(pPager), pgno);
  if( pPager->state>=PAGER_EXCLUSIVE && (pPg==0 || pPg->needSync==0) ){
    rc = sqlite3Io.xSeek(&pPager->fd, (pgno-1)*(i64)pPager->pageSize);
    if( rc==SQLITE_OK ){
      rc = sqlite3Io.xWrite(&pPager->fd, aData, pPager->pageSize);
    }
    if( pPg ) pPg->dirty = 0;
  }
  if( pPg ){
    /* No page should ever be explicitly rolled back that is in use, except
    ** for page 1 which is held in use in order to keep the lock on the
    ** database active. However such a page may be rolled back as a result
................................................................................
** To tell if a master journal can be deleted, check to each of the
** children.  If all children are either missing or do not refer to
** a different master journal, then this master journal can be deleted.
*/
static int pager_delmaster(const char *zMaster){
  int rc;
  int master_open = 0;
  OsFile master;
  char *zMasterJournal = 0; /* Contents of master journal file */
  i64 nMasterJournal;       /* Size of master journal file */

  /* Open the master journal file exclusively in case some other process
  ** is running this routine also. Not that it makes too much difference.
  */
  memset(&master, 0, sizeof(master));
  rc = sqlite3Io.xOpenReadOnly(zMaster, &master);
  if( rc!=SQLITE_OK ) goto delmaster_out;
  master_open = 1;
  rc = sqlite3Io.xFileSize(&master, &nMasterJournal);
  if( rc!=SQLITE_OK ) goto delmaster_out;

  if( nMasterJournal>0 ){
    char *zJournal;
    char *zMasterPtr = 0;

    /* Load the entire master journal file into space obtained from
................................................................................
    ** sqliteMalloc() and pointed to by zMasterJournal. 
    */
    zMasterJournal = (char *)sqliteMalloc(nMasterJournal);
    if( !zMasterJournal ){
      rc = SQLITE_NOMEM;
      goto delmaster_out;
    }
    rc = sqlite3Io.xRead(&master, zMasterJournal, nMasterJournal);
    if( rc!=SQLITE_OK ) goto delmaster_out;

    zJournal = zMasterJournal;
    while( (zJournal-zMasterJournal)<nMasterJournal ){
      if( sqlite3Io.xFileExists(zJournal) ){
        /* One of the journals pointed to by the master journal exists.
        ** Open it and check if it points at the master journal. If
        ** so, return without deleting the master journal file.
        */
        OsFile journal;
        int c;

        memset(&journal, 0, sizeof(journal));
        rc = sqlite3Io.xOpenReadOnly(zJournal, &journal);
        if( rc!=SQLITE_OK ){
          goto delmaster_out;
        }

        rc = readMasterJournal(&journal, &zMasterPtr);
        sqlite3Io.xClose(&journal);
        if( rc!=SQLITE_OK ){
          goto delmaster_out;
        }

        c = zMasterPtr!=0 && strcmp(zMasterPtr, zMaster)==0;
        sqliteFree(zMasterPtr);
................................................................................
static int pager_reload_cache(Pager *pPager){
  PgHdr *pPg;
  int rc = SQLITE_OK;
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    char zBuf[SQLITE_MAX_PAGE_SIZE];
    if( !pPg->dirty ) continue;
    if( (int)pPg->pgno <= pPager->origDbSize ){
      rc = sqlite3Io.xSeek(&pPager->fd, pPager->pageSize*(i64)(pPg->pgno-1));
      if( rc==SQLITE_OK ){
        rc = sqlite3Io.xRead(&pPager->fd, zBuf, pPager->pageSize);
      }
      TRACE3("REFETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      if( rc ) break;
      CODEC(pPager, zBuf, pPg->pgno, 2);
    }else{
      memset(zBuf, 0, pPager->pageSize);
    }
................................................................................

/*
** Truncate the main file of the given pager to the number of pages
** indicated.
*/
static int pager_truncate(Pager *pPager, int nPage){
  assert( pPager->state>=PAGER_EXCLUSIVE );
  return sqlite3Io.xTruncate(&pPager->fd, pPager->pageSize*(i64)nPage);
}

/*
** Playback the journal and thus restore the database file to
** the state it was in before we started making changes.  
**
** The journal file format is as follows: 
................................................................................
  int rc;                  /* Result code of a subroutine */
  char *zMaster = 0;       /* Name of master journal file if any */

  /* Figure out how many records are in the journal.  Abort early if
  ** the journal is empty.
  */
  assert( pPager->journalOpen );
  rc = sqlite3Io.xFileSize(&pPager->jfd, &szJ);
  if( rc!=SQLITE_OK ){
    goto end_playback;
  }

  /* Read the master journal name from the journal, if it is present.
  ** If a master journal file name is specified, but the file is not
  ** present on disk, then the journal is not hot and does not need to be
  ** played back.
  */
  rc = readMasterJournal(&pPager->jfd, &zMaster);
  assert( rc!=SQLITE_DONE );
  if( rc!=SQLITE_OK || (zMaster && !sqlite3Io.xFileExists(zMaster)) ){
    sqliteFree(zMaster);
    zMaster = 0;
    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
    goto end_playback;
  }
  sqlite3Io.xSeek(&pPager->jfd, 0);
  pPager->journalOff = 0;

  /* This loop terminates either when the readJournalHdr() call returns
  ** SQLITE_DONE or an IO error occurs. */
  while( 1 ){

    /* Read the next journal header from the journal file.  If there are
................................................................................
      rc = pager_truncate(pPager, mxPg);
      if( rc!=SQLITE_OK ){
        goto end_playback;
      }
      pPager->dbSize = mxPg;
    }

    /* rc = sqlite3Io.xSeek(&pPager->jfd, JOURNAL_HDR_SZ(pPager)); */
    if( rc!=SQLITE_OK ) goto end_playback;
  
    /* Copy original pages out of the journal and back into the database file.
    */
    for(i=0; i<nRec; i++){
      rc = pager_playback_one_page(pPager, &pPager->jfd, 1);
      if( rc!=SQLITE_OK ){
        if( rc==SQLITE_DONE ){
          rc = SQLITE_OK;
          pPager->journalOff = szJ;
          break;
        }else{
          goto end_playback;
................................................................................
  int i;                   /* Loop counter */
  int rc;

  szJ = pPager->journalOff;
#ifndef NDEBUG 
  {
    i64 os_szJ;
    rc = sqlite3Io.xFileSize(&pPager->jfd, &os_szJ);
    if( rc!=SQLITE_OK ) return rc;
    assert( szJ==os_szJ );
  }
#endif

  /* Set hdrOff to be the offset to the first journal header written
  ** this statement transaction, or the end of the file if no journal
................................................................................
    rc = pager_truncate(pPager, pPager->stmtSize);
  }
  pPager->dbSize = pPager->stmtSize;

  /* Figure out how many records are in the statement journal.
  */
  assert( pPager->stmtInUse && pPager->journalOpen );
  sqlite3Io.xSeek(&pPager->stfd, 0);
  nRec = pPager->stmtNRec;
  
  /* Copy original pages out of the statement journal and back into the
  ** database file.  Note that the statement journal omits checksums from
  ** each record since power-failure recovery is not important to statement
  ** journals.
  */
  for(i=nRec-1; i>=0; i--){
    rc = pager_playback_one_page(pPager, &pPager->stfd, 0);
    assert( rc!=SQLITE_DONE );
    if( rc!=SQLITE_OK ) goto end_stmt_playback;
  }

  /* Now roll some pages back from the transaction journal. Pager.stmtJSize
  ** was the size of the journal file when this statement was started, so
  ** everything after that needs to be rolled back, either into the
  ** database, the memory cache, or both.
  **
  ** If it is not zero, then Pager.stmtHdrOff is the offset to the start
  ** of the first journal header written during this statement transaction.
  */
  rc = sqlite3Io.xSeek(&pPager->jfd, pPager->stmtJSize);
  if( rc!=SQLITE_OK ){
    goto end_stmt_playback;
  }
  pPager->journalOff = pPager->stmtJSize;
  pPager->cksumInit = pPager->stmtCksum;
  assert( JOURNAL_HDR_SZ(pPager)<(pPager->pageSize+8) );
  while( pPager->journalOff <= (hdrOff-(pPager->pageSize+8)) ){
    rc = pager_playback_one_page(pPager, &pPager->jfd, 1);
    assert( rc!=SQLITE_DONE );
    if( rc!=SQLITE_OK ) goto end_stmt_playback;
  }

  while( pPager->journalOff < szJ ){
    u32 nRec;
    u32 dummy;
................................................................................
      assert( rc!=SQLITE_DONE );
      goto end_stmt_playback;
    }
    if( nRec==0 ){
      nRec = (szJ - pPager->journalOff) / (pPager->pageSize+8);
    }
    for(i=nRec-1; i>=0 && pPager->journalOff < szJ; i--){
      rc = pager_playback_one_page(pPager, &pPager->jfd, 1);
      assert( rc!=SQLITE_DONE );
      if( rc!=SQLITE_OK ) goto end_stmt_playback;
    }
  }

  pPager->journalOff = szJ;
  
................................................................................
** (zFile must be at least SQLITE_TEMPNAME_SIZE bytes long.)  Write
** the file descriptor into *fd.  Return SQLITE_OK on success or some
** other error code if we fail.
**
** The OS will automatically delete the temporary file when it is
** closed.
*/
static int sqlite3pager_opentemp(char *zFile, OsFile *fd){
  int cnt = 8;
  int rc;
  sqlite3_opentemp_count++;  /* Used for testing and analysis only */
  do{
    cnt--;
    sqlite3Io.xTempFileName(zFile);
    rc = sqlite3Io.xOpenExclusive(zFile, fd, 1);
  }while( cnt>0 && rc!=SQLITE_OK && rc!=SQLITE_NOMEM );
  return rc;
}

/*
** Create a new page cache and put a pointer to the page cache in *ppPager.
** The file to be cached need not exist.  The file is not locked until
................................................................................
  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 */
){
  Pager *pPager;
  char *zFullPathname = 0;
  int nameLen;
  OsFile fd;
  int rc = SQLITE_OK;
  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;
................................................................................
  strcpy(pPager->zFilename, zFullPathname);
  strcpy(pPager->zDirectory, zFullPathname);
  for(i=nameLen; i>0 && pPager->zDirectory[i-1]!='/'; i--){}
  if( i>0 ) pPager->zDirectory[i-1] = 0;
  strcpy(pPager->zJournal, zFullPathname);
  sqliteFree(zFullPathname);
  strcpy(&pPager->zJournal[nameLen], "-journal");
  sqlite3Io.xCopyOsFile(&pPager->fd,&fd);
  pPager->journalOpen = 0;
  pPager->useJournal = useJournal && !memDb;
  pPager->noReadlock = noReadlock && readOnly;
  pPager->stmtOpen = 0;
  pPager->stmtInUse = 0;
  pPager->nRef = 0;
  pPager->dbSize = memDb-1;
................................................................................
/*
** Read the first N bytes from the beginning of the file into memory
** that pDest points to.  No error checking is done.
*/
void sqlite3pager_read_fileheader(Pager *pPager, int N, unsigned char *pDest){
  memset(pDest, 0, N);
  if( MEMDB==0 ){
    sqlite3Io.xSeek(&pPager->fd, 0);
    sqlite3Io.xRead(&pPager->fd, pDest, N);
    clear_simulated_io_error();
  }
}

/*
** Return the total number of pages in the disk file associated with
** pPager. 
................................................................................
*/
int sqlite3pager_pagecount(Pager *pPager){
  i64 n;
  assert( pPager!=0 );
  if( pPager->dbSize>=0 ){
    n = pPager->dbSize;
  } else {
    if( sqlite3Io.xFileSize(&pPager->fd, &n)!=SQLITE_OK ){
      pPager->errMask |= PAGER_ERR_DISK;
      return 0;
    }
    if( n>0 && n<pPager->pageSize ){
      n = 1;
    }else{
      n /= pPager->pageSize;
................................................................................
  assert( PAGER_SHARED==SHARED_LOCK );
  assert( PAGER_RESERVED==RESERVED_LOCK );
  assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
  if( pPager->state>=locktype ){
    rc = SQLITE_OK;
  }else{
    do {
      rc = sqlite3Io.xLock(&pPager->fd, locktype);
    }while( rc==SQLITE_BUSY && sqlite3InvokeBusyHandler(pPager->pBusyHandler) );
    if( rc==SQLITE_OK ){
      pPager->state = locktype;
    }
  }
  return rc;
}
................................................................................
      ** operation. So disable IO error simulation so that testing
      ** works more easily.
      */
      disable_simulated_io_errors();
      sqlite3pager_rollback(pPager);
      enable_simulated_io_errors();
      if( !MEMDB ){
        sqlite3Io.xUnlock(&pPager->fd, NO_LOCK);
      }
      assert( pPager->errMask || pPager->journalOpen==0 );
      break;
    }
    case PAGER_SHARED: {
      if( !MEMDB ){
        sqlite3Io.xUnlock(&pPager->fd, NO_LOCK);
      }
      break;
    }
    default: {
      /* Do nothing */
      break;
    }
................................................................................
      ** was turned off after the transaction was started.  Ticket #615 */
#ifndef NDEBUG
      {
        /* Make sure the pPager->nRec counter we are keeping agrees
        ** with the nRec computed from the size of the journal file.
        */
        i64 jSz;
        rc = sqlite3Io.xFileSize(&pPager->jfd, &jSz);
        if( rc!=0 ) return rc;
        assert( pPager->journalOff==jSz );
      }
#endif
      {
        /* Write the nRec value into the journal file header. If in
        ** full-synchronous mode, sync the journal first. This ensures that
        ** all data has really hit the disk before nRec is updated to mark
        ** it as a candidate for rollback. 
        */
        if( pPager->fullSync ){
          TRACE2("SYNC journal of %d\n", PAGERID(pPager));
          rc = sqlite3Io.xSync(&pPager->jfd, 0);
          if( rc!=0 ) return rc;
        }
        rc = sqlite3Io.xSeek(&pPager->jfd,
                           pPager->journalHdr + sizeof(aJournalMagic));
        if( rc ) return rc;
        rc = write32bits(&pPager->jfd, pPager->nRec);
        if( rc ) return rc;

        rc = sqlite3Io.xSeek(&pPager->jfd, pPager->journalOff);
        if( rc ) return rc;
      }
      TRACE2("SYNC journal of %d\n", PAGERID(pPager));
      rc = sqlite3Io.xSync(&pPager->jfd, pPager->fullSync);
      if( rc!=0 ) return rc;
      pPager->journalStarted = 1;
    }
    pPager->needSync = 0;

    /* Erase the needSync flag from every page.
    */
................................................................................
  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  while( pList ){
    assert( pList->dirty );
    rc = sqlite3Io.xSeek(&pPager->fd, (pList->pgno-1)*(i64)pPager->pageSize);
    if( rc ) return rc;
    /* If there are dirty pages in the page cache with page numbers greater
    ** than Pager.dbSize, this means sqlite3pager_truncate() was called to
    ** make the file smaller (presumably by auto-vacuum code). Do not write
    ** any such pages to the file.
    */
    if( pList->pgno<=pPager->dbSize ){
      CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
      TRACE3("STORE %d page %d\n", PAGERID(pPager), pList->pgno);
      rc = sqlite3Io.xWrite(&pPager->fd, PGHDR_TO_DATA(pList),
                             pPager->pageSize);
      CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 0);
      TEST_INCR(pPager->nWrite);
    }
#ifndef NDEBUG
    else{
      TRACE3("NOSTORE %d page %d\n", PAGERID(pPager), pList->pgno);
................................................................................
** If the current size of the database file is 0 but a journal file
** exists, that is probably an old journal left over from a prior
** database with the same name.  Just delete the journal.
*/
static int hasHotJournal(Pager *pPager){
  if( !pPager->useJournal ) return 0;
  if( !sqlite3Io.xFileExists(pPager->zJournal) ) return 0;
  if( sqlite3Io.xCheckReservedLock(&pPager->fd) ) return 0;
  if( sqlite3pager_pagecount(pPager)==0 ){
    sqlite3Io.xDelete(pPager->zJournal);
    return 0;
  }else{
    return 1;
  }
}
................................................................................
       ** database is safe to read while this process is still rolling it 
       ** back.
       ** 
       ** Because the intermediate RESERVED lock is not requested, the
       ** second process will get to this point in the code and fail to
       ** obtain it's own EXCLUSIVE lock on the database file.
       */
       rc = sqlite3Io.xLock(&pPager->fd, EXCLUSIVE_LOCK);
       if( rc!=SQLITE_OK ){
         sqlite3Io.xUnlock(&pPager->fd, NO_LOCK);
         pPager->state = PAGER_UNLOCK;
         return rc;
       }
       pPager->state = PAGER_EXCLUSIVE;

       /* Open the journal for reading only.  Return SQLITE_BUSY if
       ** we are unable to open the journal file. 
................................................................................
       ** The journal file does not need to be locked itself.  The
       ** journal file is never open unless the main database file holds
       ** a write lock, so there is never any chance of two or more
       ** processes opening the journal at the same time.
       */
       rc = sqlite3Io.xOpenReadOnly(pPager->zJournal, &pPager->jfd);
       if( rc!=SQLITE_OK ){
         sqlite3Io.xUnlock(&pPager->fd, NO_LOCK);
         pPager->state = PAGER_UNLOCK;
         return SQLITE_BUSY;
       }
       pPager->journalOpen = 1;
       pPager->journalStarted = 0;
       pPager->journalOff = 0;
       pPager->setMaster = 0;
................................................................................
      return rc;
    }
    if( sqlite3pager_pagecount(pPager)<(int)pgno ){
      memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
    }else{
      int rc;
      assert( MEMDB==0 );
      rc = sqlite3Io.xSeek(&pPager->fd, (pgno-1)*(i64)pPager->pageSize);
      if( rc==SQLITE_OK ){
        rc = sqlite3Io.xRead(&pPager->fd, PGHDR_TO_DATA(pPg),
                              pPager->pageSize);
      }
      TRACE3("FETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      CODEC(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
      if( rc!=SQLITE_OK ){
        i64 fileSize;
        if( sqlite3Io.xFileSize(&pPager->fd,&fileSize)!=SQLITE_OK
               || fileSize>=pgno*pPager->pageSize ){
          sqlite3pager_unref(PGHDR_TO_DATA(pPg));
          return rc;
        }else{
          clear_simulated_io_error();
          memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
        }
................................................................................
                                 pPager->tempFile);
  pPager->journalOff = 0;
  pPager->setMaster = 0;
  pPager->journalHdr = 0;
  if( rc!=SQLITE_OK ){
    goto failed_to_open_journal;
  }
  SET_FULLSYNC(pPager->jfd, pPager->fullSync);
  SET_FULLSYNC(pPager->fd, pPager->fullSync);
  sqlite3Io.xOpenDirectory(pPager->zDirectory, &pPager->jfd);
  pPager->journalOpen = 1;
  pPager->journalStarted = 0;
  pPager->needSync = 0;
  pPager->alwaysRollback = 0;
  pPager->nRec = 0;
  if( pPager->errMask!=0 ){
    rc = pager_errcode(pPager);
................................................................................
    }
  }
  return rc;

failed_to_open_journal:
  sqliteFree(pPager->aInJournal);
  pPager->aInJournal = 0;
  sqlite3Io.xUnlock(&pPager->fd, NO_LOCK);
  pPager->state = PAGER_UNLOCK;
  return rc;
}

/*
** Acquire a write-lock on the database.  The lock is removed when
** the any of the following happen:
................................................................................
  assert( pPager->state!=PAGER_UNLOCK );
  if( pPager->state==PAGER_SHARED ){
    assert( pPager->aInJournal==0 );
    if( MEMDB ){
      pPager->state = PAGER_EXCLUSIVE;
      pPager->origDbSize = pPager->dbSize;
    }else{
      rc = sqlite3Io.xLock(&pPager->fd, RESERVED_LOCK);
      if( rc==SQLITE_OK ){
        pPager->state = PAGER_RESERVED;
        if( exFlag ){
          rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
        }
      }
      if( rc!=SQLITE_OK ){
................................................................................
          assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
          CODEC(pPager, pData, pPg->pgno, 7);
          cksum = pager_cksum(pPager, pPg->pgno, pData);
          saved = *(u32*)PGHDR_TO_EXTRA(pPg, pPager);
          store32bits(cksum, pPg, pPager->pageSize);
          szPg = pPager->pageSize+8;
          store32bits(pPg->pgno, pPg, -4);
          rc = sqlite3Io.xWrite(&pPager->jfd, &((char*)pData)[-4], szPg);
          pPager->journalOff += szPg;
          TRACE4("JOURNAL %d page %d needSync=%d\n",
                  PAGERID(pPager), pPg->pgno, pPg->needSync);
          CODEC(pPager, pData, pPg->pgno, 0);
          *(u32*)PGHDR_TO_EXTRA(pPg, pPager) = saved;
          if( rc!=SQLITE_OK ){
            sqlite3pager_rollback(pPager);
................................................................................
        if( pHist->pStmt ){
          memcpy(pHist->pStmt, PGHDR_TO_DATA(pPg), pPager->pageSize);
        }
        TRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
      }else{
        store32bits(pPg->pgno, pPg, -4);
        CODEC(pPager, pData, pPg->pgno, 7);
        rc = sqlite3Io.xWrite(&pPager->stfd,((char*)pData)-4,
                               pPager->pageSize+4);
        TRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
        CODEC(pPager, pData, pPg->pgno, 0);
        if( rc!=SQLITE_OK ){
          sqlite3pager_rollback(pPager);
          pPager->errMask |= PAGER_ERR_FULL;
          return rc;
................................................................................
  if( !pPager->journalOpen ){
    pPager->stmtAutoopen = 1;
    return SQLITE_OK;
  }
  assert( pPager->journalOpen );
  pPager->aInStmt = sqliteMalloc( pPager->dbSize/8 + 1 );
  if( pPager->aInStmt==0 ){
    sqlite3Io.xLock(&pPager->fd, SHARED_LOCK);
    return SQLITE_NOMEM;
  }
#ifndef NDEBUG
  rc = sqlite3Io.xFileSize(&pPager->jfd, &pPager->stmtJSize);
  if( rc ) goto stmt_begin_failed;
  assert( pPager->stmtJSize == pPager->journalOff );
#endif
  pPager->stmtJSize = pPager->journalOff;
  pPager->stmtSize = pPager->dbSize;
  pPager->stmtHdrOff = 0;
  pPager->stmtCksum = pPager->cksumInit;
................................................................................
** Commit a statement.
*/
int sqlite3pager_stmt_commit(Pager *pPager){
  if( pPager->stmtInUse ){
    PgHdr *pPg, *pNext;
    TRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
    if( !MEMDB ){
      sqlite3Io.xSeek(&pPager->stfd, 0);
      /* sqlite3Io.xTruncate(&pPager->stfd, 0); */
      sqliteFree( pPager->aInStmt );
      pPager->aInStmt = 0;
    }
    for(pPg=pPager->pStmt; pPg; pPg=pNext){
      pNext = pPg->pNextStmt;
      assert( pPg->inStmt );
      pPg->inStmt = 0;
................................................................................
    /* Write all dirty pages to the database file */
    pPg = pager_get_all_dirty_pages(pPager);
    rc = pager_write_pagelist(pPg);
    if( rc!=SQLITE_OK ) goto sync_exit;

    /* Sync the database file. */
    if( !pPager->noSync ){
      rc = sqlite3Io.xSync(&pPager->fd, 0);
    }

    pPager->state = PAGER_SYNCED;
  }

sync_exit:
  return rc;
................................................................................
#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
/*
** Return the current state of the file lock for the given pager.
** The return value is one of NO_LOCK, SHARED_LOCK, RESERVED_LOCK,
** PENDING_LOCK, or EXCLUSIVE_LOCK.
*/
int sqlite3pager_lockstate(Pager *pPager){
#ifdef OS_TEST
  return pPager->fd->fd.locktype;
#else
  return pPager->fd.locktype;
#endif
}
#endif

#ifdef SQLITE_DEBUG
/*
** Print a listing of all referenced pages and their ref count.
*/







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** 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 1.221 2005/11/29 03:13:22 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>
................................................................................
** The following two macros are used within the TRACEX() macros above
** to print out file-descriptors. 
**
** PAGERID() takes a pointer to a Pager struct as it's argument. The
** associated file-descriptor is returned. FILEHANDLEID() takes an OsFile
** struct as it's argument.
*/
#define PAGERID(p) FILEHANDLEID(&(p)->fd)
#define FILEHANDLEID(fd) (sqlite3Io.xFileHandle(&fd))

/*
** The page cache as a whole is always in one of the following
** states:
**
**   PAGER_UNLOCK        The page cache is not currently reading or 
**                       writing the database file.  There is no
................................................................................
  int nRef;                   /* Number of in-memory pages with PgHdr.nRef>0 */
  int mxPage;                 /* Maximum number of pages to hold in cache */
  u8 *aInJournal;             /* One bit for each page in the database file */
  u8 *aInStmt;                /* One bit for each page in the database */
  char *zFilename;            /* Name of the database file */
  char *zJournal;             /* Name of the journal file */
  char *zDirectory;           /* Directory hold database and journal files */
  OsFile *fd, *jfd;           /* File descriptors for database and journal */
  OsFile *stfd;               /* File descriptor for the statement subjournal*/
  BusyHandler *pBusyHandler;  /* Pointer to sqlite.busyHandler */
  PgHdr *pFirst, *pLast;      /* List of free pages */
  PgHdr *pFirstSynced;        /* First free page with PgHdr.needSync==0 */
  PgHdr *pAll;                /* List of all pages */
  PgHdr *pStmt;               /* List of pages in the statement subjournal */
  i64 journalOff;             /* Current byte offset in the journal file */
  i64 journalHdr;             /* Byte offset to previous journal header */
................................................................................
  if( c ){
    offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager);
  }
  assert( offset%JOURNAL_HDR_SZ(pPager)==0 );
  assert( offset>=c );
  assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
  pPager->journalOff = offset;
  return sqlite3Io.xSeek(pPager->jfd, pPager->journalOff);
}

/*
** The journal file must be open when this routine is called. A journal
** header (JOURNAL_HDR_SZ bytes) is written into the journal file at the
** current location.
**
................................................................................
  **
  ** Possibly for a pager not in no-sync mode, the journal magic should not
  ** be written until nRec is filled in as part of next syncJournal(). 
  **
  ** Actually maybe the whole journal header should be delayed until that
  ** point. Think about this.
  */
  rc = sqlite3Io.xWrite(pPager->jfd, aJournalMagic, sizeof(aJournalMagic));

  if( rc==SQLITE_OK ){
    /* The nRec Field. 0xFFFFFFFF for no-sync journals. */
    rc = write32bits(pPager->jfd, pPager->noSync ? 0xffffffff : 0);
  }
  if( rc==SQLITE_OK ){
    /* The random check-hash initialiser */ 
    sqlite3Randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
    rc = write32bits(pPager->jfd, pPager->cksumInit);
  }
  if( rc==SQLITE_OK ){
    /* The initial database size */
    rc = write32bits(pPager->jfd, pPager->dbSize);
  }
  if( rc==SQLITE_OK ){
    /* The assumed sector size for this process */
    rc = write32bits(pPager->jfd, pPager->sectorSize);
  }

  /* The journal header has been written successfully. Seek the journal
  ** file descriptor to the end of the journal header sector.
  */
  if( rc==SQLITE_OK ){
    rc = sqlite3Io.xSeek(pPager->jfd, pPager->journalOff-1);
    if( rc==SQLITE_OK ){
      rc = sqlite3Io.xWrite(pPager->jfd, "\000", 1);
    }
  }
  return rc;
}

/*
** The journal file must be open when this is called. A journal header file
................................................................................
  rc = seekJournalHdr(pPager);
  if( rc ) return rc;

  if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
    return SQLITE_DONE;
  }

  rc = sqlite3Io.xRead(pPager->jfd, aMagic, sizeof(aMagic));
  if( rc ) return rc;

  if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
    return SQLITE_DONE;
  }

  rc = read32bits(pPager->jfd, pNRec);
  if( rc ) return rc;

  rc = read32bits(pPager->jfd, &pPager->cksumInit);
  if( rc ) return rc;

  rc = read32bits(pPager->jfd, pDbSize);
  if( rc ) return rc;

  /* Update the assumed sector-size to match the value used by 
  ** the process that created this journal. If this journal was
  ** created by a process other than this one, then this routine
  ** is being called from within pager_playback(). The local value
  ** of Pager.sectorSize is restored at the end of that routine.
  */
  rc = read32bits(pPager->jfd, (u32 *)&pPager->sectorSize);
  if( rc ) return rc;

  pPager->journalOff += JOURNAL_HDR_SZ(pPager);
  rc = sqlite3Io.xSeek(pPager->jfd, pPager->journalOff);
  return rc;
}


/*
** Write the supplied master journal name into the journal file for pager
** pPager at the current location. The master journal name must be the last
................................................................................
  */
  if( pPager->fullSync ){
    rc = seekJournalHdr(pPager);
    if( rc!=SQLITE_OK ) return rc;
  }
  pPager->journalOff += (len+20);

  rc = write32bits(pPager->jfd, PAGER_MJ_PGNO(pPager));
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3Io.xWrite(pPager->jfd, zMaster, len);
  if( rc!=SQLITE_OK ) return rc;

  rc = write32bits(pPager->jfd, len);
  if( rc!=SQLITE_OK ) return rc;

  rc = write32bits(pPager->jfd, cksum);
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3Io.xWrite(pPager->jfd, aJournalMagic, sizeof(aJournalMagic));
  pPager->needSync = !pPager->noSync;
  return rc;
}

/*
** Add or remove a page from the list of all pages that are in the
** statement journal.
................................................................................
  pPager->pLast = 0;
  pPager->pAll = 0;
  memset(pPager->aHash, 0, sizeof(pPager->aHash));
  pPager->nPage = 0;
  if( pPager->state>=PAGER_RESERVED ){
    sqlite3pager_rollback(pPager);
  }
  sqlite3Io.xUnlock(pPager->fd, NO_LOCK);
  pPager->state = PAGER_UNLOCK;
  pPager->dbSize = -1;
  pPager->nRef = 0;
  assert( pPager->journalOpen==0 );
}

/*
................................................................................
    }
    pPager->dirtyCache = 0;
    pPager->nRec = 0;
  }else{
    assert( pPager->aInJournal==0 );
    assert( pPager->dirtyCache==0 || pPager->useJournal==0 );
  }
  rc = sqlite3Io.xUnlock(pPager->fd, SHARED_LOCK);
  pPager->state = PAGER_SHARED;
  pPager->origDbSize = 0;
  pPager->setMaster = 0;
  return rc;
}

/*
................................................................................
  Pgno pgno;                    /* The page number of a page in journal */
  u32 cksum;                    /* Checksum used for sanity checking */
  u8 aData[SQLITE_MAX_PAGE_SIZE];  /* Temp storage for a page */

  /* useCksum should be true for the main journal and false for
  ** statement journals.  Verify that this is always the case
  */
  assert( jfd == (useCksum ? pPager->jfd : pPager->stfd) );


  rc = read32bits(jfd, &pgno);
  if( rc!=SQLITE_OK ) return rc;
  rc = sqlite3Io.xRead(jfd, &aData, pPager->pageSize);
  if( rc!=SQLITE_OK ) return rc;
  pPager->journalOff += pPager->pageSize + 4;
................................................................................
  ** page content is in the main journal either because the page is not in
  ** cache or else it is marked as needSync==0.
  */
  pPg = pager_lookup(pPager, pgno);
  assert( pPager->state>=PAGER_EXCLUSIVE || pPg!=0 );
  TRACE3("PLAYBACK %d page %d\n", PAGERID(pPager), pgno);
  if( pPager->state>=PAGER_EXCLUSIVE && (pPg==0 || pPg->needSync==0) ){
    rc = sqlite3Io.xSeek(pPager->fd, (pgno-1)*(i64)pPager->pageSize);
    if( rc==SQLITE_OK ){
      rc = sqlite3Io.xWrite(pPager->fd, aData, pPager->pageSize);
    }
    if( pPg ) pPg->dirty = 0;
  }
  if( pPg ){
    /* No page should ever be explicitly rolled back that is in use, except
    ** for page 1 which is held in use in order to keep the lock on the
    ** database active. However such a page may be rolled back as a result
................................................................................
** To tell if a master journal can be deleted, check to each of the
** children.  If all children are either missing or do not refer to
** a different master journal, then this master journal can be deleted.
*/
static int pager_delmaster(const char *zMaster){
  int rc;
  int master_open = 0;
  OsFile *master = 0;
  char *zMasterJournal = 0; /* Contents of master journal file */
  i64 nMasterJournal;       /* Size of master journal file */

  /* Open the master journal file exclusively in case some other process
  ** is running this routine also. Not that it makes too much difference.
  */

  rc = sqlite3Io.xOpenReadOnly(zMaster, &master);
  if( rc!=SQLITE_OK ) goto delmaster_out;
  master_open = 1;
  rc = sqlite3Io.xFileSize(master, &nMasterJournal);
  if( rc!=SQLITE_OK ) goto delmaster_out;

  if( nMasterJournal>0 ){
    char *zJournal;
    char *zMasterPtr = 0;

    /* Load the entire master journal file into space obtained from
................................................................................
    ** sqliteMalloc() and pointed to by zMasterJournal. 
    */
    zMasterJournal = (char *)sqliteMalloc(nMasterJournal);
    if( !zMasterJournal ){
      rc = SQLITE_NOMEM;
      goto delmaster_out;
    }
    rc = sqlite3Io.xRead(master, zMasterJournal, nMasterJournal);
    if( rc!=SQLITE_OK ) goto delmaster_out;

    zJournal = zMasterJournal;
    while( (zJournal-zMasterJournal)<nMasterJournal ){
      if( sqlite3Io.xFileExists(zJournal) ){
        /* One of the journals pointed to by the master journal exists.
        ** Open it and check if it points at the master journal. If
        ** so, return without deleting the master journal file.
        */
        OsFile *journal = 0;
        int c;


        rc = sqlite3Io.xOpenReadOnly(zJournal, &journal);
        if( rc!=SQLITE_OK ){
          goto delmaster_out;
        }

        rc = readMasterJournal(journal, &zMasterPtr);
        sqlite3Io.xClose(&journal);
        if( rc!=SQLITE_OK ){
          goto delmaster_out;
        }

        c = zMasterPtr!=0 && strcmp(zMasterPtr, zMaster)==0;
        sqliteFree(zMasterPtr);
................................................................................
static int pager_reload_cache(Pager *pPager){
  PgHdr *pPg;
  int rc = SQLITE_OK;
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    char zBuf[SQLITE_MAX_PAGE_SIZE];
    if( !pPg->dirty ) continue;
    if( (int)pPg->pgno <= pPager->origDbSize ){
      rc = sqlite3Io.xSeek(pPager->fd, pPager->pageSize*(i64)(pPg->pgno-1));
      if( rc==SQLITE_OK ){
        rc = sqlite3Io.xRead(pPager->fd, zBuf, pPager->pageSize);
      }
      TRACE3("REFETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      if( rc ) break;
      CODEC(pPager, zBuf, pPg->pgno, 2);
    }else{
      memset(zBuf, 0, pPager->pageSize);
    }
................................................................................

/*
** Truncate the main file of the given pager to the number of pages
** indicated.
*/
static int pager_truncate(Pager *pPager, int nPage){
  assert( pPager->state>=PAGER_EXCLUSIVE );
  return sqlite3Io.xTruncate(pPager->fd, pPager->pageSize*(i64)nPage);
}

/*
** Playback the journal and thus restore the database file to
** the state it was in before we started making changes.  
**
** The journal file format is as follows: 
................................................................................
  int rc;                  /* Result code of a subroutine */
  char *zMaster = 0;       /* Name of master journal file if any */

  /* Figure out how many records are in the journal.  Abort early if
  ** the journal is empty.
  */
  assert( pPager->journalOpen );
  rc = sqlite3Io.xFileSize(pPager->jfd, &szJ);
  if( rc!=SQLITE_OK ){
    goto end_playback;
  }

  /* Read the master journal name from the journal, if it is present.
  ** If a master journal file name is specified, but the file is not
  ** present on disk, then the journal is not hot and does not need to be
  ** played back.
  */
  rc = readMasterJournal(pPager->jfd, &zMaster);
  assert( rc!=SQLITE_DONE );
  if( rc!=SQLITE_OK || (zMaster && !sqlite3Io.xFileExists(zMaster)) ){
    sqliteFree(zMaster);
    zMaster = 0;
    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
    goto end_playback;
  }
  sqlite3Io.xSeek(pPager->jfd, 0);
  pPager->journalOff = 0;

  /* This loop terminates either when the readJournalHdr() call returns
  ** SQLITE_DONE or an IO error occurs. */
  while( 1 ){

    /* Read the next journal header from the journal file.  If there are
................................................................................
      rc = pager_truncate(pPager, mxPg);
      if( rc!=SQLITE_OK ){
        goto end_playback;
      }
      pPager->dbSize = mxPg;
    }

    /* rc = sqlite3Io.xSeek(pPager->jfd, JOURNAL_HDR_SZ(pPager)); */
    if( rc!=SQLITE_OK ) goto end_playback;
  
    /* Copy original pages out of the journal and back into the database file.
    */
    for(i=0; i<nRec; i++){
      rc = pager_playback_one_page(pPager, pPager->jfd, 1);
      if( rc!=SQLITE_OK ){
        if( rc==SQLITE_DONE ){
          rc = SQLITE_OK;
          pPager->journalOff = szJ;
          break;
        }else{
          goto end_playback;
................................................................................
  int i;                   /* Loop counter */
  int rc;

  szJ = pPager->journalOff;
#ifndef NDEBUG 
  {
    i64 os_szJ;
    rc = sqlite3Io.xFileSize(pPager->jfd, &os_szJ);
    if( rc!=SQLITE_OK ) return rc;
    assert( szJ==os_szJ );
  }
#endif

  /* Set hdrOff to be the offset to the first journal header written
  ** this statement transaction, or the end of the file if no journal
................................................................................
    rc = pager_truncate(pPager, pPager->stmtSize);
  }
  pPager->dbSize = pPager->stmtSize;

  /* Figure out how many records are in the statement journal.
  */
  assert( pPager->stmtInUse && pPager->journalOpen );
  sqlite3Io.xSeek(pPager->stfd, 0);
  nRec = pPager->stmtNRec;
  
  /* Copy original pages out of the statement journal and back into the
  ** database file.  Note that the statement journal omits checksums from
  ** each record since power-failure recovery is not important to statement
  ** journals.
  */
  for(i=nRec-1; i>=0; i--){
    rc = pager_playback_one_page(pPager, pPager->stfd, 0);
    assert( rc!=SQLITE_DONE );
    if( rc!=SQLITE_OK ) goto end_stmt_playback;
  }

  /* Now roll some pages back from the transaction journal. Pager.stmtJSize
  ** was the size of the journal file when this statement was started, so
  ** everything after that needs to be rolled back, either into the
  ** database, the memory cache, or both.
  **
  ** If it is not zero, then Pager.stmtHdrOff is the offset to the start
  ** of the first journal header written during this statement transaction.
  */
  rc = sqlite3Io.xSeek(pPager->jfd, pPager->stmtJSize);
  if( rc!=SQLITE_OK ){
    goto end_stmt_playback;
  }
  pPager->journalOff = pPager->stmtJSize;
  pPager->cksumInit = pPager->stmtCksum;
  assert( JOURNAL_HDR_SZ(pPager)<(pPager->pageSize+8) );
  while( pPager->journalOff <= (hdrOff-(pPager->pageSize+8)) ){
    rc = pager_playback_one_page(pPager, pPager->jfd, 1);
    assert( rc!=SQLITE_DONE );
    if( rc!=SQLITE_OK ) goto end_stmt_playback;
  }

  while( pPager->journalOff < szJ ){
    u32 nRec;
    u32 dummy;
................................................................................
      assert( rc!=SQLITE_DONE );
      goto end_stmt_playback;
    }
    if( nRec==0 ){
      nRec = (szJ - pPager->journalOff) / (pPager->pageSize+8);
    }
    for(i=nRec-1; i>=0 && pPager->journalOff < szJ; i--){
      rc = pager_playback_one_page(pPager, pPager->jfd, 1);
      assert( rc!=SQLITE_DONE );
      if( rc!=SQLITE_OK ) goto end_stmt_playback;
    }
  }

  pPager->journalOff = szJ;
  
................................................................................
** (zFile must be at least SQLITE_TEMPNAME_SIZE bytes long.)  Write
** the file descriptor into *fd.  Return SQLITE_OK on success or some
** other error code if we fail.
**
** The OS will automatically delete the temporary file when it is
** closed.
*/
static int sqlite3pager_opentemp(char *zFile, OsFile **pFd){
  int cnt = 8;
  int rc;
  sqlite3_opentemp_count++;  /* Used for testing and analysis only */
  do{
    cnt--;
    sqlite3Io.xTempFileName(zFile);
    rc = sqlite3Io.xOpenExclusive(zFile, pFd, 1);
  }while( cnt>0 && rc!=SQLITE_OK && rc!=SQLITE_NOMEM );
  return rc;
}

/*
** Create a new page cache and put a pointer to the page cache in *ppPager.
** The file to be cached need not exist.  The file is not locked until
................................................................................
  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 */
){
  Pager *pPager;
  char *zFullPathname = 0;
  int nameLen;
  OsFile *fd;
  int rc = SQLITE_OK;
  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;
................................................................................
  strcpy(pPager->zFilename, zFullPathname);
  strcpy(pPager->zDirectory, zFullPathname);
  for(i=nameLen; i>0 && pPager->zDirectory[i-1]!='/'; i--){}
  if( i>0 ) pPager->zDirectory[i-1] = 0;
  strcpy(pPager->zJournal, zFullPathname);
  sqliteFree(zFullPathname);
  strcpy(&pPager->zJournal[nameLen], "-journal");
  pPager->fd = fd;
  pPager->journalOpen = 0;
  pPager->useJournal = useJournal && !memDb;
  pPager->noReadlock = noReadlock && readOnly;
  pPager->stmtOpen = 0;
  pPager->stmtInUse = 0;
  pPager->nRef = 0;
  pPager->dbSize = memDb-1;
................................................................................
/*
** Read the first N bytes from the beginning of the file into memory
** that pDest points to.  No error checking is done.
*/
void sqlite3pager_read_fileheader(Pager *pPager, int N, unsigned char *pDest){
  memset(pDest, 0, N);
  if( MEMDB==0 ){
    sqlite3Io.xSeek(pPager->fd, 0);
    sqlite3Io.xRead(pPager->fd, pDest, N);
    clear_simulated_io_error();
  }
}

/*
** Return the total number of pages in the disk file associated with
** pPager. 
................................................................................
*/
int sqlite3pager_pagecount(Pager *pPager){
  i64 n;
  assert( pPager!=0 );
  if( pPager->dbSize>=0 ){
    n = pPager->dbSize;
  } else {
    if( sqlite3Io.xFileSize(pPager->fd, &n)!=SQLITE_OK ){
      pPager->errMask |= PAGER_ERR_DISK;
      return 0;
    }
    if( n>0 && n<pPager->pageSize ){
      n = 1;
    }else{
      n /= pPager->pageSize;
................................................................................
  assert( PAGER_SHARED==SHARED_LOCK );
  assert( PAGER_RESERVED==RESERVED_LOCK );
  assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
  if( pPager->state>=locktype ){
    rc = SQLITE_OK;
  }else{
    do {
      rc = sqlite3Io.xLock(pPager->fd, locktype);
    }while( rc==SQLITE_BUSY && sqlite3InvokeBusyHandler(pPager->pBusyHandler) );
    if( rc==SQLITE_OK ){
      pPager->state = locktype;
    }
  }
  return rc;
}
................................................................................
      ** operation. So disable IO error simulation so that testing
      ** works more easily.
      */
      disable_simulated_io_errors();
      sqlite3pager_rollback(pPager);
      enable_simulated_io_errors();
      if( !MEMDB ){
        sqlite3Io.xUnlock(pPager->fd, NO_LOCK);
      }
      assert( pPager->errMask || pPager->journalOpen==0 );
      break;
    }
    case PAGER_SHARED: {
      if( !MEMDB ){
        sqlite3Io.xUnlock(pPager->fd, NO_LOCK);
      }
      break;
    }
    default: {
      /* Do nothing */
      break;
    }
................................................................................
      ** was turned off after the transaction was started.  Ticket #615 */
#ifndef NDEBUG
      {
        /* Make sure the pPager->nRec counter we are keeping agrees
        ** with the nRec computed from the size of the journal file.
        */
        i64 jSz;
        rc = sqlite3Io.xFileSize(pPager->jfd, &jSz);
        if( rc!=0 ) return rc;
        assert( pPager->journalOff==jSz );
      }
#endif
      {
        /* Write the nRec value into the journal file header. If in
        ** full-synchronous mode, sync the journal first. This ensures that
        ** all data has really hit the disk before nRec is updated to mark
        ** it as a candidate for rollback. 
        */
        if( pPager->fullSync ){
          TRACE2("SYNC journal of %d\n", PAGERID(pPager));
          rc = sqlite3Io.xSync(pPager->jfd, 0);
          if( rc!=0 ) return rc;
        }
        rc = sqlite3Io.xSeek(pPager->jfd,
                           pPager->journalHdr + sizeof(aJournalMagic));
        if( rc ) return rc;
        rc = write32bits(pPager->jfd, pPager->nRec);
        if( rc ) return rc;

        rc = sqlite3Io.xSeek(pPager->jfd, pPager->journalOff);
        if( rc ) return rc;
      }
      TRACE2("SYNC journal of %d\n", PAGERID(pPager));
      rc = sqlite3Io.xSync(pPager->jfd, pPager->fullSync);
      if( rc!=0 ) return rc;
      pPager->journalStarted = 1;
    }
    pPager->needSync = 0;

    /* Erase the needSync flag from every page.
    */
................................................................................
  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  while( pList ){
    assert( pList->dirty );
    rc = sqlite3Io.xSeek(pPager->fd, (pList->pgno-1)*(i64)pPager->pageSize);
    if( rc ) return rc;
    /* If there are dirty pages in the page cache with page numbers greater
    ** than Pager.dbSize, this means sqlite3pager_truncate() was called to
    ** make the file smaller (presumably by auto-vacuum code). Do not write
    ** any such pages to the file.
    */
    if( pList->pgno<=pPager->dbSize ){
      CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
      TRACE3("STORE %d page %d\n", PAGERID(pPager), pList->pgno);
      rc = sqlite3Io.xWrite(pPager->fd, PGHDR_TO_DATA(pList),
                             pPager->pageSize);
      CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 0);
      TEST_INCR(pPager->nWrite);
    }
#ifndef NDEBUG
    else{
      TRACE3("NOSTORE %d page %d\n", PAGERID(pPager), pList->pgno);
................................................................................
** If the current size of the database file is 0 but a journal file
** exists, that is probably an old journal left over from a prior
** database with the same name.  Just delete the journal.
*/
static int hasHotJournal(Pager *pPager){
  if( !pPager->useJournal ) return 0;
  if( !sqlite3Io.xFileExists(pPager->zJournal) ) return 0;
  if( sqlite3Io.xCheckReservedLock(pPager->fd) ) return 0;
  if( sqlite3pager_pagecount(pPager)==0 ){
    sqlite3Io.xDelete(pPager->zJournal);
    return 0;
  }else{
    return 1;
  }
}
................................................................................
       ** database is safe to read while this process is still rolling it 
       ** back.
       ** 
       ** Because the intermediate RESERVED lock is not requested, the
       ** second process will get to this point in the code and fail to
       ** obtain it's own EXCLUSIVE lock on the database file.
       */
       rc = sqlite3Io.xLock(pPager->fd, EXCLUSIVE_LOCK);
       if( rc!=SQLITE_OK ){
         sqlite3Io.xUnlock(pPager->fd, NO_LOCK);
         pPager->state = PAGER_UNLOCK;
         return rc;
       }
       pPager->state = PAGER_EXCLUSIVE;

       /* Open the journal for reading only.  Return SQLITE_BUSY if
       ** we are unable to open the journal file. 
................................................................................
       ** The journal file does not need to be locked itself.  The
       ** journal file is never open unless the main database file holds
       ** a write lock, so there is never any chance of two or more
       ** processes opening the journal at the same time.
       */
       rc = sqlite3Io.xOpenReadOnly(pPager->zJournal, &pPager->jfd);
       if( rc!=SQLITE_OK ){
         sqlite3Io.xUnlock(pPager->fd, NO_LOCK);
         pPager->state = PAGER_UNLOCK;
         return SQLITE_BUSY;
       }
       pPager->journalOpen = 1;
       pPager->journalStarted = 0;
       pPager->journalOff = 0;
       pPager->setMaster = 0;
................................................................................
      return rc;
    }
    if( sqlite3pager_pagecount(pPager)<(int)pgno ){
      memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
    }else{
      int rc;
      assert( MEMDB==0 );
      rc = sqlite3Io.xSeek(pPager->fd, (pgno-1)*(i64)pPager->pageSize);
      if( rc==SQLITE_OK ){
        rc = sqlite3Io.xRead(pPager->fd, PGHDR_TO_DATA(pPg),
                              pPager->pageSize);
      }
      TRACE3("FETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      CODEC(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
      if( rc!=SQLITE_OK ){
        i64 fileSize;
        if( sqlite3Io.xFileSize(pPager->fd,&fileSize)!=SQLITE_OK
               || fileSize>=pgno*pPager->pageSize ){
          sqlite3pager_unref(PGHDR_TO_DATA(pPg));
          return rc;
        }else{
          clear_simulated_io_error();
          memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
        }
................................................................................
                                 pPager->tempFile);
  pPager->journalOff = 0;
  pPager->setMaster = 0;
  pPager->journalHdr = 0;
  if( rc!=SQLITE_OK ){
    goto failed_to_open_journal;
  }
  sqlite3Io.xSetFullSync(pPager->jfd, pPager->fullSync);
  sqlite3Io.xSetFullSync(pPager->fd, pPager->fullSync);
  sqlite3Io.xOpenDirectory(pPager->zDirectory, pPager->jfd);
  pPager->journalOpen = 1;
  pPager->journalStarted = 0;
  pPager->needSync = 0;
  pPager->alwaysRollback = 0;
  pPager->nRec = 0;
  if( pPager->errMask!=0 ){
    rc = pager_errcode(pPager);
................................................................................
    }
  }
  return rc;

failed_to_open_journal:
  sqliteFree(pPager->aInJournal);
  pPager->aInJournal = 0;
  sqlite3Io.xUnlock(pPager->fd, NO_LOCK);
  pPager->state = PAGER_UNLOCK;
  return rc;
}

/*
** Acquire a write-lock on the database.  The lock is removed when
** the any of the following happen:
................................................................................
  assert( pPager->state!=PAGER_UNLOCK );
  if( pPager->state==PAGER_SHARED ){
    assert( pPager->aInJournal==0 );
    if( MEMDB ){
      pPager->state = PAGER_EXCLUSIVE;
      pPager->origDbSize = pPager->dbSize;
    }else{
      rc = sqlite3Io.xLock(pPager->fd, RESERVED_LOCK);
      if( rc==SQLITE_OK ){
        pPager->state = PAGER_RESERVED;
        if( exFlag ){
          rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
        }
      }
      if( rc!=SQLITE_OK ){
................................................................................
          assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
          CODEC(pPager, pData, pPg->pgno, 7);
          cksum = pager_cksum(pPager, pPg->pgno, pData);
          saved = *(u32*)PGHDR_TO_EXTRA(pPg, pPager);
          store32bits(cksum, pPg, pPager->pageSize);
          szPg = pPager->pageSize+8;
          store32bits(pPg->pgno, pPg, -4);
          rc = sqlite3Io.xWrite(pPager->jfd, &((char*)pData)[-4], szPg);
          pPager->journalOff += szPg;
          TRACE4("JOURNAL %d page %d needSync=%d\n",
                  PAGERID(pPager), pPg->pgno, pPg->needSync);
          CODEC(pPager, pData, pPg->pgno, 0);
          *(u32*)PGHDR_TO_EXTRA(pPg, pPager) = saved;
          if( rc!=SQLITE_OK ){
            sqlite3pager_rollback(pPager);
................................................................................
        if( pHist->pStmt ){
          memcpy(pHist->pStmt, PGHDR_TO_DATA(pPg), pPager->pageSize);
        }
        TRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
      }else{
        store32bits(pPg->pgno, pPg, -4);
        CODEC(pPager, pData, pPg->pgno, 7);
        rc = sqlite3Io.xWrite(pPager->stfd,((char*)pData)-4,
                               pPager->pageSize+4);
        TRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
        CODEC(pPager, pData, pPg->pgno, 0);
        if( rc!=SQLITE_OK ){
          sqlite3pager_rollback(pPager);
          pPager->errMask |= PAGER_ERR_FULL;
          return rc;
................................................................................
  if( !pPager->journalOpen ){
    pPager->stmtAutoopen = 1;
    return SQLITE_OK;
  }
  assert( pPager->journalOpen );
  pPager->aInStmt = sqliteMalloc( pPager->dbSize/8 + 1 );
  if( pPager->aInStmt==0 ){
    sqlite3Io.xLock(pPager->fd, SHARED_LOCK);
    return SQLITE_NOMEM;
  }
#ifndef NDEBUG
  rc = sqlite3Io.xFileSize(pPager->jfd, &pPager->stmtJSize);
  if( rc ) goto stmt_begin_failed;
  assert( pPager->stmtJSize == pPager->journalOff );
#endif
  pPager->stmtJSize = pPager->journalOff;
  pPager->stmtSize = pPager->dbSize;
  pPager->stmtHdrOff = 0;
  pPager->stmtCksum = pPager->cksumInit;
................................................................................
** Commit a statement.
*/
int sqlite3pager_stmt_commit(Pager *pPager){
  if( pPager->stmtInUse ){
    PgHdr *pPg, *pNext;
    TRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
    if( !MEMDB ){
      sqlite3Io.xSeek(pPager->stfd, 0);
      /* sqlite3Io.xTruncate(pPager->stfd, 0); */
      sqliteFree( pPager->aInStmt );
      pPager->aInStmt = 0;
    }
    for(pPg=pPager->pStmt; pPg; pPg=pNext){
      pNext = pPg->pNextStmt;
      assert( pPg->inStmt );
      pPg->inStmt = 0;
................................................................................
    /* Write all dirty pages to the database file */
    pPg = pager_get_all_dirty_pages(pPager);
    rc = pager_write_pagelist(pPg);
    if( rc!=SQLITE_OK ) goto sync_exit;

    /* Sync the database file. */
    if( !pPager->noSync ){
      rc = sqlite3Io.xSync(pPager->fd, 0);
    }

    pPager->state = PAGER_SYNCED;
  }

sync_exit:
  return rc;
................................................................................
#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
/*
** Return the current state of the file lock for the given pager.
** The return value is one of NO_LOCK, SHARED_LOCK, RESERVED_LOCK,
** PENDING_LOCK, or EXCLUSIVE_LOCK.
*/
int sqlite3pager_lockstate(Pager *pPager){
  return sqlite3Io.xLockState(pPager->fd);




}
#endif

#ifdef SQLITE_DEBUG
/*
** Print a listing of all referenced pages and their ref count.
*/

Changes to src/test1.c.

9
10
11
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13
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17
18
19
20
21
22
23
....
2425
2426
2427
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2439
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2450
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2452
2453
....
2457
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2480
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2488
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the printf() interface to SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.166 2005/11/26 00:25:03 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
*/
static int test_sqlite3OsOpenReadWrite(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  OsFile * pFile;
  int rc;
  int dummy;
  char zBuf[100];

  if( objc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filename", 0);
    return TCL_ERROR;
  }

  pFile = sqliteMalloc(sizeof(OsFile));
  rc = sqlite3Io.xOpenReadWrite(Tcl_GetString(objv[1]), pFile, &dummy);
  if( rc!=SQLITE_OK ){
    sqliteFree(pFile);
    Tcl_SetResult(interp, (char *)errorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  makePointerStr(interp, zBuf, pFile);
  Tcl_SetResult(interp, zBuf, 0);
  return TCL_ERROR;
}
................................................................................
*/
static int test_sqlite3OsClose(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  OsFile * pFile;
  int rc;

  if( objc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filehandle", 0);
    return TCL_ERROR;
  }

  if( getFilePointer(interp, Tcl_GetString(objv[1]), &pFile) ){
    return TCL_ERROR;
  }
  rc = sqlite3Io.xClose(pFile);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)errorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  sqliteFree(pFile);
  return TCL_OK;
}

/*
** Usage:  sqlite3OsLock <file handle> <locktype>
*/
static int test_sqlite3OsLock(







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....
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2428
2429
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2431
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2433
2434
2435
2436
2437
2438
2439
2440
2441
2442

2443
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2445
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2448
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2451
....
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2474
2475
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2477
2478

2479
2480
2481
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**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the printf() interface to SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.167 2005/11/29 03:13:22 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
*/
static int test_sqlite3OsOpenReadWrite(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  OsFile *pFile;
  int rc;
  int dummy;
  char zBuf[100];

  if( objc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filename", 0);
    return TCL_ERROR;
  }


  rc = sqlite3Io.xOpenReadWrite(Tcl_GetString(objv[1]), &pFile, &dummy);
  if( rc!=SQLITE_OK ){

    Tcl_SetResult(interp, (char *)errorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  makePointerStr(interp, zBuf, pFile);
  Tcl_SetResult(interp, zBuf, 0);
  return TCL_ERROR;
}
................................................................................
*/
static int test_sqlite3OsClose(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  OsFile *pFile;
  int rc;

  if( objc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filehandle", 0);
    return TCL_ERROR;
  }

  if( getFilePointer(interp, Tcl_GetString(objv[1]), &pFile) ){
    return TCL_ERROR;
  }
  rc = sqlite3Io.xClose(&pFile);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)errorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }

  return TCL_OK;
}

/*
** Usage:  sqlite3OsLock <file handle> <locktype>
*/
static int test_sqlite3OsLock(

Changes to src/test2.c.

9
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17
18
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21
22
23
...
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555
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the pager.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test2.c,v 1.36 2005/11/26 00:25:04 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  int rc;
  int n;
  i64 offset;
  OsFile fd;
  int readOnly = 0;
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " N-MEGABYTES FILE\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], &n) ) return TCL_ERROR;
  memset(&fd, 0, sizeof(fd));
  rc = sqlite3Io.xOpenReadWrite(argv[2], &fd, &readOnly);
  if( rc ){
    Tcl_AppendResult(interp, "open failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  offset = n;
  offset *= 1024*1024;
  rc = sqlite3Io.xSeek(&fd, offset);
  if( rc ){
    Tcl_AppendResult(interp, "seek failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  rc = sqlite3Io.xWrite(&fd, "Hello, World!", 14);
  sqlite3Io.xClose(&fd);
  if( rc ){
    Tcl_AppendResult(interp, "write failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}







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9
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13
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530
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532
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535
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542
543
544
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546
547
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549
550
551
552
553
554
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the pager.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test2.c,v 1.37 2005/11/29 03:13:22 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  int rc;
  int n;
  i64 offset;
  OsFile *fd = 0;
  int readOnly = 0;
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " N-MEGABYTES FILE\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], &n) ) return TCL_ERROR;

  rc = sqlite3Io.xOpenReadWrite(argv[2], &fd, &readOnly);
  if( rc ){
    Tcl_AppendResult(interp, "open failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  offset = n;
  offset *= 1024*1024;
  rc = sqlite3Io.xSeek(fd, offset);
  if( rc ){
    Tcl_AppendResult(interp, "seek failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  rc = sqlite3Io.xWrite(fd, "Hello, World!", 14);
  sqlite3Io.xClose(&fd);
  if( rc ){
    Tcl_AppendResult(interp, "write failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

Changes to src/test6.c.

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483

484
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487
** the effect on the database file of an OS crash or power failure.  This
** is used to test the ability of SQLite to recover from those situations.
*/
#if SQLITE_TEST          /* This file is used for the testing only */
#include "sqliteInt.h"
#include "os.h"
#include "tcl.h"


/*
** A copy of the original sqlite3Io structure
*/
static struct sqlite3IoVtbl origIo;

/*
** The pAux part of OsFile points to this structure.

*/
typedef struct OsTestFile OsTestFile;
struct OsTestFile {
  u8 **apBlk;         /* Array of blocks that have been written to. */
  int nBlk;           /* Size of apBlock. */
  int nMaxWrite;      /* Largest offset written to. */
  char *zName;        /* File name */
  OsFile *pBase;      /* Base class */
  OsTestFile *pNext;  /* Next in a list of them all */
};

/*
** Size of a simulated disk block
*/
#define BLOCKSIZE 512
#define BLOCK_OFFSET(x) ((x) * BLOCKSIZE)
................................................................................
** A list of all open files.
*/
static OsTestFile *pAllFiles = 0;

/*
** Initialise the os_test.c specific fields of pFile.
*/
static void initFile(OsFile *id, char const *zName){
  OsTestFile *pFile = sqliteMalloc(sizeof(OsTestFile) + strlen(zName)+1);
  id->pAux = pFile;
  pFile->nMaxWrite = 0; 
  pFile->nBlk = 0; 
  pFile->apBlk = 0; 
  pFile->zName = (char *)(&pFile[1]);
  strcpy(pFile->zName, zName);
  pFile->pBase = id;
  pFile->pNext = pAllFiles;
................................................................................
}

/*
** Undo the work done by initFile. Delete the OsTestFile structure
** and unlink the structure from the pAllFiles list.
*/
static void closeFile(OsFile *id){
  OsTestFile *pFile = (OsTestFile*)id->pAux;
  if( pFile==pAllFiles ){
    pAllFiles = pFile->pNext;
  }else{
    OsTestFile *p;
    for(p=pAllFiles; p->pNext!=pFile; p=p->pNext ){
      assert( p );
    }
    p->pNext = pFile->pNext;
  }
  sqliteFree(pFile);
}

/*
** Return the current seek offset from the start of the file. This
** is unix-only code.
*/
static i64 osTell(OsTestFile *pFile){
  return lseek(pFile->pBase->h, 0, SEEK_CUR);
}

/*
** Load block 'blk' into the cache of pFile.
*/
static int cacheBlock(OsTestFile *pFile, int blk){
  if( blk>=pFile->nBlk ){
    int n = ((pFile->nBlk * 2) + 100 + blk);
    /* if( pFile->nBlk==0 ){ printf("DIRTY %s\n", pFile->zName); } */
    pFile->apBlk = (u8 **)sqliteRealloc(pFile->apBlk, n * sizeof(u8*));
    if( !pFile->apBlk ) return SQLITE_NOMEM;
    memset(&pFile->apBlk[pFile->nBlk], 0, (n - pFile->nBlk)*sizeof(u8*));
    pFile->nBlk = n;
................................................................................
  return SQLITE_OK;
}

/*
** Write the cache of pFile to disk. If crash is non-zero, randomly
** skip blocks when writing. The cache is deleted before returning.
*/
static int writeCache2(OsTestFile *pFile, int crash){
  int i;
  int nMax = pFile->nMaxWrite;
  i64 offset;
  int rc = SQLITE_OK;

  offset = osTell(pFile);
  for(i=0; i<pFile->nBlk; i++){
................................................................................
  }
  return rc;
}

/*
** Write the cache to disk.
*/
static int writeCache(OsTestFile *pFile){
  if( pFile->apBlk ){
    int c = crashRequired(pFile->zName);
    if( c ){
      OsTestFile *p;
#ifdef TRACE_WRITECACHE
      printf("\nCrash during sync of %s\n", pFile->zName);
#endif
................................................................................
/*
** Close the file.
*/
static int crashClose(OsFile *id){
  if( id->pAux ) return SQLITE_OK;
  if( id->isOpen ){
    /* printf("CLOSE %s (%d blocks)\n", (*id)->zName, (*id)->nBlk); */
    writeCache((OsTestFile*)id->pAux);
    origIo.xClose(id);
  }
  closeFile(id);
  return SQLITE_OK;
}

static int crashRead(OsFile *id, void *pBuf, int amt){
  i64 offset;       /* The current offset from the start of the file */
................................................................................
  sqlite3Io.xClose = crashClose;
  sqlite3Io.xSync = crashSync;
  sqlite3Io.xTruncate = crashTruncate;
  sqlite3Io.xFileSize = crashFileSize;
  sqlite3Io.xOpenReadWrite = crashOpenReadWrite;
  sqlite3Io.xOpenExclusive = crashOpenExclusive;
  sqlite3Io.xOpenReadOnly = crashOpenReadOnly;
  sqlite3Io.xCopyOsFile = crashCopyOsFile;
  return TCL_OK;
}


/*
** This procedure registers the TCL procedures defined in this file.
*/
int Sqlitetest6_Init(Tcl_Interp *interp){

  Tcl_CreateObjCommand(interp, "sqlite3_crashparams", crashParamsObjCmd, 0, 0);

  return TCL_OK;
}

#endif /* SQLITE_TEST */







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** the effect on the database file of an OS crash or power failure.  This
** is used to test the ability of SQLite to recover from those situations.
*/
#if SQLITE_TEST          /* This file is used for the testing only */
#include "sqliteInt.h"
#include "os.h"
#include "tcl.h"
#if 0

/*
** A copy of the original sqlite3Io structure
*/
static struct sqlite3IoVtbl origIo;

/*
** The OsFile structure for the crash-test backend.  The pBase field
** points to an OsFile structure for the native backend.
*/

struct OsFile {
  u8 **apBlk;         /* Array of blocks that have been written to. */
  int nBlk;           /* Size of apBlock. */
  int nMaxWrite;      /* Largest offset written to. */
  char *zName;        /* File name */
  OsFile *pBase;      /* Base class */
  OsFile *pNext;      /* Next in a list of them all */
};

/*
** Size of a simulated disk block
*/
#define BLOCKSIZE 512
#define BLOCK_OFFSET(x) ((x) * BLOCKSIZE)
................................................................................
** A list of all open files.
*/
static OsTestFile *pAllFiles = 0;

/*
** Initialise the os_test.c specific fields of pFile.
*/
static void initFile(OsFile **pId, char const *zName){
  OsFile *pFile = *pId = sqliteMalloc(sizeof(OsFile) + strlen(zName)+1);

  pFile->nMaxWrite = 0; 
  pFile->nBlk = 0; 
  pFile->apBlk = 0; 
  pFile->zName = (char *)(&pFile[1]);
  strcpy(pFile->zName, zName);
  pFile->pBase = id;
  pFile->pNext = pAllFiles;
................................................................................
}

/*
** Undo the work done by initFile. Delete the OsTestFile structure
** and unlink the structure from the pAllFiles list.
*/
static void closeFile(OsFile *id){
  OsFile *pFile = id;
  if( pFile==pAllFiles ){
    pAllFiles = pFile->pNext;
  }else{
    OsFile *p;
    for(p=pAllFiles; p->pNext!=pFile; p=p->pNext ){
      assert( p );
    }
    p->pNext = pFile->pNext;
  }
  sqliteFree(pFile);
}

/*
** Return the current seek offset from the start of the file. This
** is unix-only code.
*/
static i64 osTell(OsFile *pFile){
  return lseek(pFile->pBase->h, 0, SEEK_CUR);
}

/*
** Load block 'blk' into the cache of pFile.
*/
static int cacheBlock(OsFile *pFile, int blk){
  if( blk>=pFile->nBlk ){
    int n = ((pFile->nBlk * 2) + 100 + blk);
    /* if( pFile->nBlk==0 ){ printf("DIRTY %s\n", pFile->zName); } */
    pFile->apBlk = (u8 **)sqliteRealloc(pFile->apBlk, n * sizeof(u8*));
    if( !pFile->apBlk ) return SQLITE_NOMEM;
    memset(&pFile->apBlk[pFile->nBlk], 0, (n - pFile->nBlk)*sizeof(u8*));
    pFile->nBlk = n;
................................................................................
  return SQLITE_OK;
}

/*
** Write the cache of pFile to disk. If crash is non-zero, randomly
** skip blocks when writing. The cache is deleted before returning.
*/
static int writeCache2(OsFile *pFile, int crash){
  int i;
  int nMax = pFile->nMaxWrite;
  i64 offset;
  int rc = SQLITE_OK;

  offset = osTell(pFile);
  for(i=0; i<pFile->nBlk; i++){
................................................................................
  }
  return rc;
}

/*
** Write the cache to disk.
*/
static int writeCache(OsFile *pFile){
  if( pFile->apBlk ){
    int c = crashRequired(pFile->zName);
    if( c ){
      OsTestFile *p;
#ifdef TRACE_WRITECACHE
      printf("\nCrash during sync of %s\n", pFile->zName);
#endif
................................................................................
/*
** Close the file.
*/
static int crashClose(OsFile *id){
  if( id->pAux ) return SQLITE_OK;
  if( id->isOpen ){
    /* printf("CLOSE %s (%d blocks)\n", (*id)->zName, (*id)->nBlk); */
    writeCache(id);
    origIo.xClose(&id->pBase);
  }
  closeFile(id);
  return SQLITE_OK;
}

static int crashRead(OsFile *id, void *pBuf, int amt){
  i64 offset;       /* The current offset from the start of the file */
................................................................................
  sqlite3Io.xClose = crashClose;
  sqlite3Io.xSync = crashSync;
  sqlite3Io.xTruncate = crashTruncate;
  sqlite3Io.xFileSize = crashFileSize;
  sqlite3Io.xOpenReadWrite = crashOpenReadWrite;
  sqlite3Io.xOpenExclusive = crashOpenExclusive;
  sqlite3Io.xOpenReadOnly = crashOpenReadOnly;
  sqlite3Io.xSet
  return TCL_OK;
}

#endif
/*
** This procedure registers the TCL procedures defined in this file.
*/
int Sqlitetest6_Init(Tcl_Interp *interp){
#if 0
  Tcl_CreateObjCommand(interp, "sqlite3_crashparams", crashParamsObjCmd, 0, 0);
#endif
  return TCL_OK;
}

#endif /* SQLITE_TEST */

Changes to src/vdbeaux.c.

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  static const u32 masks[5] = {
    NOPUSH_MASK_0 + (NOPUSH_MASK_1<<16),
    NOPUSH_MASK_2 + (NOPUSH_MASK_3<<16),
    NOPUSH_MASK_4 + (NOPUSH_MASK_5<<16),
    NOPUSH_MASK_6 + (NOPUSH_MASK_7<<16),
    NOPUSH_MASK_8 + (NOPUSH_MASK_9<<16)
  };
  assert( op>=0 && op<32*5 );
  return (masks[op>>5] & (1<<(op&0x1F)));
}

#ifndef NDEBUG
int sqlite3VdbeOpcodeNoPush(u8 op){
  return opcodeNoPush(op);
}
................................................................................
  ** committed atomicly.
  */
#ifndef SQLITE_OMIT_DISKIO
  else{
    int needSync = 0;
    char *zMaster = 0;   /* File-name for the master journal */
    char const *zMainFile = sqlite3BtreeGetFilename(db->aDb[0].pBt);
    OsFile master;

    /* Select a master journal file name */
    do {
      u32 random;
      sqliteFree(zMaster);
      sqlite3Randomness(sizeof(random), &random);
      zMaster = sqlite3MPrintf("%s-mj%08X", zMainFile, random&0x7fffffff);
      if( !zMaster ){
        return SQLITE_NOMEM;
      }
    }while( sqlite3Io.xFileExists(zMaster) );

    /* Open the master journal. */
    memset(&master, 0, sizeof(master));
    rc = sqlite3Io.xOpenExclusive(zMaster, &master, 0);
    if( rc!=SQLITE_OK ){
      sqliteFree(zMaster);
      return rc;
    }
 
    /* Write the name of each database file in the transaction into the new
................................................................................
      if( i==1 ) continue;   /* Ignore the TEMP database */
      if( pBt && sqlite3BtreeIsInTrans(pBt) ){
        char const *zFile = sqlite3BtreeGetJournalname(pBt);
        if( zFile[0]==0 ) continue;  /* Ignore :memory: databases */
        if( !needSync && !sqlite3BtreeSyncDisabled(pBt) ){
          needSync = 1;
        }
        rc = sqlite3Io.xWrite(&master, zFile, strlen(zFile)+1);
        if( rc!=SQLITE_OK ){
          sqlite3Io.xClose(&master);
          sqlite3Io.xDelete(zMaster);
          sqliteFree(zMaster);
          return rc;
        }
      }
................................................................................
    }


    /* Sync the master journal file. Before doing this, open the directory
    ** the master journal file is store in so that it gets synced too.
    */
    zMainFile = sqlite3BtreeGetDirname(db->aDb[0].pBt);
    rc = sqlite3Io.xOpenDirectory(zMainFile, &master);
    if( rc!=SQLITE_OK ||
          (needSync && (rc=sqlite3Io.xSync(&master,0))!=SQLITE_OK) ){
      sqlite3Io.xClose(&master);
      sqlite3Io.xDelete(zMaster);
      sqliteFree(zMaster);
      return rc;
    }

    /* Sync all the db files involved in the transaction. The same call







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202
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1021
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1023
1024
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  static const u32 masks[5] = {
    NOPUSH_MASK_0 + (NOPUSH_MASK_1<<16),
    NOPUSH_MASK_2 + (NOPUSH_MASK_3<<16),
    NOPUSH_MASK_4 + (NOPUSH_MASK_5<<16),
    NOPUSH_MASK_6 + (NOPUSH_MASK_7<<16),
    NOPUSH_MASK_8 + (NOPUSH_MASK_9<<16)
  };
  assert( op<32*5 );
  return (masks[op>>5] & (1<<(op&0x1F)));
}

#ifndef NDEBUG
int sqlite3VdbeOpcodeNoPush(u8 op){
  return opcodeNoPush(op);
}
................................................................................
  ** committed atomicly.
  */
#ifndef SQLITE_OMIT_DISKIO
  else{
    int needSync = 0;
    char *zMaster = 0;   /* File-name for the master journal */
    char const *zMainFile = sqlite3BtreeGetFilename(db->aDb[0].pBt);
    OsFile *master = 0;

    /* Select a master journal file name */
    do {
      u32 random;
      sqliteFree(zMaster);
      sqlite3Randomness(sizeof(random), &random);
      zMaster = sqlite3MPrintf("%s-mj%08X", zMainFile, random&0x7fffffff);
      if( !zMaster ){
        return SQLITE_NOMEM;
      }
    }while( sqlite3Io.xFileExists(zMaster) );

    /* Open the master journal. */

    rc = sqlite3Io.xOpenExclusive(zMaster, &master, 0);
    if( rc!=SQLITE_OK ){
      sqliteFree(zMaster);
      return rc;
    }
 
    /* Write the name of each database file in the transaction into the new
................................................................................
      if( i==1 ) continue;   /* Ignore the TEMP database */
      if( pBt && sqlite3BtreeIsInTrans(pBt) ){
        char const *zFile = sqlite3BtreeGetJournalname(pBt);
        if( zFile[0]==0 ) continue;  /* Ignore :memory: databases */
        if( !needSync && !sqlite3BtreeSyncDisabled(pBt) ){
          needSync = 1;
        }
        rc = sqlite3Io.xWrite(master, zFile, strlen(zFile)+1);
        if( rc!=SQLITE_OK ){
          sqlite3Io.xClose(&master);
          sqlite3Io.xDelete(zMaster);
          sqliteFree(zMaster);
          return rc;
        }
      }
................................................................................
    }


    /* Sync the master journal file. Before doing this, open the directory
    ** the master journal file is store in so that it gets synced too.
    */
    zMainFile = sqlite3BtreeGetDirname(db->aDb[0].pBt);
    rc = sqlite3Io.xOpenDirectory(zMainFile, master);
    if( rc!=SQLITE_OK ||
          (needSync && (rc=sqlite3Io.xSync(master,0))!=SQLITE_OK) ){
      sqlite3Io.xClose(&master);
      sqlite3Io.xDelete(zMaster);
      sqliteFree(zMaster);
      return rc;
    }

    /* Sync all the db files involved in the transaction. The same call

Changes to test/attach.test.

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#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is testing the ATTACH and DETACH commands
# and related functionality.
#
# $Id: attach.test,v 1.40 2005/03/29 03:11:00 danielk1977 Exp $
#

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

for {set i 2} {$i<=15} {incr i} {
  file delete -force test$i.db
................................................................................
}
for {set i 2} {$i<=15} {incr i} {
  catch {db$i close}
}
db close
file delete -force test2.db
file delete -force no-such-file


finish_test







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<

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745
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is testing the ATTACH and DETACH commands
# and related functionality.
#
# $Id: attach.test,v 1.41 2005/11/29 03:13:22 drh Exp $
#

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

for {set i 2} {$i<=15} {incr i} {
  file delete -force test$i.db
................................................................................
}
for {set i 2} {$i<=15} {incr i} {
  catch {db$i close}
}
db close
file delete -force test2.db
file delete -force no-such-file


finish_test