$(TOP)/src/vdbeapi.c \
  $(TOP)/src/vdbeaux.c \
  $(TOP)/src/vdbeblob.c \
  $(TOP)/src/vdbemem.c \
  $(TOP)/src/vdbetrace.c \
  $(TOP)/src/vdbeInt.h \
  $(TOP)/src/vtab.c \


  $(TOP)/src/walker.c \
  $(TOP)/src/where.c

# Generated source code files
#
SRC += \
  keywordhash.h \
................................................................................

vdbetrace.lo:	$(TOP)/src/vdbetrace.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/vdbetrace.c

vtab.lo:	$(TOP)/src/vtab.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/vtab.c




walker.lo:	$(TOP)/src/walker.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/walker.c

where.lo:	$(TOP)/src/where.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/where.c

tclsqlite-shell.lo:	$(TOP)/src/tclsqlite.c $(HDR)

  $(TOP)/src/vdbeapi.c \
  $(TOP)/src/vdbeaux.c \
  $(TOP)/src/vdbeblob.c \
  $(TOP)/src/vdbemem.c \
  $(TOP)/src/vdbetrace.c \
  $(TOP)/src/vdbeInt.h \
  $(TOP)/src/vtab.c \
  $(TOP)/src/wal.c \
  $(TOP)/src/wal.h \
  $(TOP)/src/walker.c \
  $(TOP)/src/where.c

# Generated source code files
#
SRC += \
  keywordhash.h \
................................................................................

vdbetrace.lo:	$(TOP)/src/vdbetrace.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/vdbetrace.c

vtab.lo:	$(TOP)/src/vtab.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/vtab.c

wal.lo:	$(TOP)/src/wal.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/wal.c

walker.lo:	$(TOP)/src/walker.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/walker.c

where.lo:	$(TOP)/src/where.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/where.c

tclsqlite-shell.lo:	$(TOP)/src/tclsqlite.c $(HDR)

#
LIBOBJ+= alter.o analyze.o attach.o auth.o \
         backup.o bitvec.o btmutex.o btree.o build.o \
         callback.o complete.o ctime.o date.o delete.o expr.o fault.o fkey.o \
         fts3.o fts3_expr.o fts3_hash.o fts3_icu.o fts3_porter.o \
         fts3_snippet.o fts3_tokenizer.o fts3_tokenizer1.o fts3_write.o \
         func.o global.o hash.o \
         icu.o insert.o journal.o legacy.o loadext.o log.o \
         main.o malloc.o mem0.o mem1.o mem2.o mem3.o mem5.o \
         memjournal.o \
         mutex.o mutex_noop.o mutex_os2.o mutex_unix.o mutex_w32.o \
         notify.o opcodes.o os.o os_os2.o os_unix.o os_win.o \
         pager.o parse.o pcache.o pcache1.o pragma.o prepare.o printf.o \
         random.o resolve.o rowset.o rtree.o select.o status.o \
         table.o tokenize.o trigger.o \
         update.o util.o vacuum.o \
         vdbe.o vdbeapi.o vdbeaux.o vdbeblob.o vdbemem.o vdbetrace.o \
         walker.o where.o utf.o vtab.o



# All of the source code files.
#
SRC = \
  $(TOP)/src/alter.c \
................................................................................
  $(TOP)/src/hash.c \
  $(TOP)/src/hash.h \
  $(TOP)/src/hwtime.h \
  $(TOP)/src/insert.c \
  $(TOP)/src/journal.c \
  $(TOP)/src/legacy.c \
  $(TOP)/src/loadext.c \
  $(TOP)/src/log.c \
  $(TOP)/src/log.h \
  $(TOP)/src/main.c \
  $(TOP)/src/malloc.c \
  $(TOP)/src/mem0.c \
  $(TOP)/src/mem1.c \
  $(TOP)/src/mem2.c \
  $(TOP)/src/mem3.c \
  $(TOP)/src/mem5.c \
................................................................................
  $(TOP)/src/vdbeapi.c \
  $(TOP)/src/vdbeaux.c \
  $(TOP)/src/vdbeblob.c \
  $(TOP)/src/vdbemem.c \
  $(TOP)/src/vdbetrace.c \
  $(TOP)/src/vdbeInt.h \
  $(TOP)/src/vtab.c \


  $(TOP)/src/walker.c \
  $(TOP)/src/where.c

# Source code for extensions
#
SRC += \
  $(TOP)/ext/fts1/fts1.c \
................................................................................

#TESTSRC += $(TOP)/ext/fts2/fts2_tokenizer.c
#TESTSRC += $(TOP)/ext/fts3/fts3_tokenizer.c

TESTSRC2 = \
  $(TOP)/src/attach.c $(TOP)/src/backup.c $(TOP)/src/btree.c                   \
  $(TOP)/src/build.c $(TOP)/src/date.c                                         \
  $(TOP)/src/expr.c $(TOP)/src/func.c $(TOP)/src/insert.c $(TOP)/src/log.c     \
  $(TOP)/src/mem5.c $(TOP)/src/os.c                                            \
  $(TOP)/src/os_os2.c $(TOP)/src/os_unix.c $(TOP)/src/os_win.c                 \
  $(TOP)/src/pager.c $(TOP)/src/pragma.c $(TOP)/src/prepare.c                  \
  $(TOP)/src/printf.c $(TOP)/src/random.c $(TOP)/src/pcache.c                  \
  $(TOP)/src/pcache1.c $(TOP)/src/select.c $(TOP)/src/tokenize.c               \
  $(TOP)/src/utf.c $(TOP)/src/util.c $(TOP)/src/vdbeapi.c $(TOP)/src/vdbeaux.c \
  $(TOP)/src/vdbe.c $(TOP)/src/vdbemem.c $(TOP)/src/where.c parse.c            \

#
LIBOBJ+= alter.o analyze.o attach.o auth.o \
         backup.o bitvec.o btmutex.o btree.o build.o \
         callback.o complete.o ctime.o date.o delete.o expr.o fault.o fkey.o \
         fts3.o fts3_expr.o fts3_hash.o fts3_icu.o fts3_porter.o \
         fts3_snippet.o fts3_tokenizer.o fts3_tokenizer1.o fts3_write.o \
         func.o global.o hash.o \
         icu.o insert.o journal.o legacy.o loadext.o \
         main.o malloc.o mem0.o mem1.o mem2.o mem3.o mem5.o \
         memjournal.o \
         mutex.o mutex_noop.o mutex_os2.o mutex_unix.o mutex_w32.o \
         notify.o opcodes.o os.o os_os2.o os_unix.o os_win.o \
         pager.o parse.o pcache.o pcache1.o pragma.o prepare.o printf.o \
         random.o resolve.o rowset.o rtree.o select.o status.o \
         table.o tokenize.o trigger.o \
         update.o util.o vacuum.o \
         vdbe.o vdbeapi.o vdbeaux.o vdbeblob.o vdbemem.o vdbetrace.o \
         wal.o walker.o where.o utf.o vtab.o



# All of the source code files.
#
SRC = \
  $(TOP)/src/alter.c \
................................................................................
  $(TOP)/src/hash.c \
  $(TOP)/src/hash.h \
  $(TOP)/src/hwtime.h \
  $(TOP)/src/insert.c \
  $(TOP)/src/journal.c \
  $(TOP)/src/legacy.c \
  $(TOP)/src/loadext.c \


  $(TOP)/src/main.c \
  $(TOP)/src/malloc.c \
  $(TOP)/src/mem0.c \
  $(TOP)/src/mem1.c \
  $(TOP)/src/mem2.c \
  $(TOP)/src/mem3.c \
  $(TOP)/src/mem5.c \
................................................................................
  $(TOP)/src/vdbeapi.c \
  $(TOP)/src/vdbeaux.c \
  $(TOP)/src/vdbeblob.c \
  $(TOP)/src/vdbemem.c \
  $(TOP)/src/vdbetrace.c \
  $(TOP)/src/vdbeInt.h \
  $(TOP)/src/vtab.c \
  $(TOP)/src/wal.c \
  $(TOP)/src/wal.h \
  $(TOP)/src/walker.c \
  $(TOP)/src/where.c

# Source code for extensions
#
SRC += \
  $(TOP)/ext/fts1/fts1.c \
................................................................................

#TESTSRC += $(TOP)/ext/fts2/fts2_tokenizer.c
#TESTSRC += $(TOP)/ext/fts3/fts3_tokenizer.c

TESTSRC2 = \
  $(TOP)/src/attach.c $(TOP)/src/backup.c $(TOP)/src/btree.c                   \
  $(TOP)/src/build.c $(TOP)/src/date.c                                         \
  $(TOP)/src/expr.c $(TOP)/src/func.c $(TOP)/src/insert.c $(TOP)/src/wal.c     \
  $(TOP)/src/mem5.c $(TOP)/src/os.c                                            \
  $(TOP)/src/os_os2.c $(TOP)/src/os_unix.c $(TOP)/src/os_win.c                 \
  $(TOP)/src/pager.c $(TOP)/src/pragma.c $(TOP)/src/prepare.c                  \
  $(TOP)/src/printf.c $(TOP)/src/random.c $(TOP)/src/pcache.c                  \
  $(TOP)/src/pcache1.c $(TOP)/src/select.c $(TOP)/src/tokenize.c               \
  $(TOP)/src/utf.c $(TOP)/src/util.c $(TOP)/src/vdbeapi.c $(TOP)/src/vdbeaux.c \
  $(TOP)/src/vdbe.c $(TOP)/src/vdbemem.c $(TOP)/src/where.c parse.c            \

** 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.
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "log.h"

/*
******************** NOTES ON THE DESIGN OF THE PAGER ************************
**
** Within this comment block, a page is deemed to have been synced
** automatically as soon as it is written when PRAGMA synchronous=OFF.
** Otherwise, the page is not synced until the xSync method of the VFS
................................................................................
    ** this happens.  One can argue that this doesn't need to be cleared
    ** until the change-counter check fails in PagerSharedLock().
    ** Clearing the page size cache here is being conservative.
    */
    pPager->dbSizeValid = 0;

    if( pagerUseLog(pPager) ){
      sqlite3LogCloseSnapshot(pPager->pLog);
    }else{
      rc = osUnlock(pPager->fd, NO_LOCK);
    }
    if( rc ){
      pPager->errCode = rc;
    }
    IOTRACE(("UNLOCK %p\n", pPager))
................................................................................
  }
  sqlite3BitvecDestroy(pPager->pInJournal);
  pPager->pInJournal = 0;
  pPager->nRec = 0;
  sqlite3PcacheCleanAll(pPager->pPCache);

  if( pagerUseLog(pPager) ){
    rc2 = sqlite3LogWriteLock(pPager->pLog, 0);
    pPager->state = PAGER_SHARED;
  }else if( !pPager->exclusiveMode ){
    rc2 = osUnlock(pPager->fd, SHARED_LOCK);
    pPager->state = PAGER_SHARED;
    pPager->changeCountDone = 0;
  }else if( pPager->state==PAGER_SYNCED ){
    pPager->state = PAGER_EXCLUSIVE;
................................................................................
    assert( pPager->tempFile );
    memset(pPg->pData, 0, pPager->pageSize);
    return SQLITE_OK;
  }

  if( pagerUseLog(pPager) ){
    /* Try to pull the page from the write-ahead log. */
    rc = sqlite3LogRead(pPager->pLog, pgno, &isInLog, pPg->pData);
  }
  if( rc==SQLITE_OK && !isInLog ){
    iOffset = (pgno-1)*(i64)pPager->pageSize;
    rc = sqlite3OsRead(pPager->fd, pPg->pData, pPager->pageSize, iOffset);
    if( rc==SQLITE_IOERR_SHORT_READ ){
      rc = SQLITE_OK;
    }
................................................................................
  ** updated as data is copied out of the rollback journal and into the
  ** database. This is not generally possible with a WAL database, as
  ** rollback involves simply truncating the log file. Therefore, if one
  ** or more frames have already been written to the log (and therefore 
  ** also copied into the backup databases) as part of this transaction,
  ** the backups must be restarted.
  */
  if( sqlite3LogDirty(pPager->pLog) ){
    sqlite3BackupRestart(pPager->pBackup);
  }

  /* For all pages in the cache that are currently dirty or have already
  ** been written (but not committed) to the log file, do one of the 
  ** following:
  **
  **   + Discard the cached page (if refcount==0), or
  **   + Reload page content from the database (if refcount>0).
  */
  pPager->dbSize = pPager->dbOrigSize;
  rc = sqlite3LogUndo(pPager->pLog, pagerUndoCallback, (void *)pPager);
  pList = sqlite3PcacheDirtyList(pPager->pPCache);
  while( pList && rc==SQLITE_OK ){
    PgHdr *pNext = pList->pDirty;
    rc = pagerUndoCallback((void *)pPager, pList->pgno);
    pList = pNext;
  }

................................................................................
  if( pPager->dbSizeValid ){
    nPage = pPager->dbSize;
  }else{
    int rc;                 /* Error returned by OsFileSize() */
    i64 n = 0;              /* File size in bytes returned by OsFileSize() */

    if( pagerUseLog(pPager) ){
      sqlite3LogDbsize(pPager->pLog, &nPage);
    }

    if( nPage==0 ){
      assert( isOpen(pPager->fd) || pPager->tempFile );
      if( isOpen(pPager->fd) ){
        if( SQLITE_OK!=(rc = sqlite3OsFileSize(pPager->fd, &n)) ){
          pager_error(pPager, rc);
................................................................................
int sqlite3PagerClose(Pager *pPager){
  u8 *pTmp = (u8 *)pPager->pTmpSpace;

  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  pPager->errCode = 0;
  pPager->exclusiveMode = 0;
  sqlite3LogClose(pPager->pLog, pPager->fd, 
    (pPager->noSync ? 0 : pPager->sync_flags), pTmp
  );
  pPager->pLog = 0;
  pager_reset(pPager);
  if( MEMDB ){
    pager_unlock(pPager);
  }else{
................................................................................
    assert( pPager->nSavepoint>0 );
    rc = addToSavepointBitvecs(pPager, pPg->pgno);
  }
  return rc;
}

/*
** This function is a wrapper around sqlite3LogFrames(). As well as logging
** the contents of the list of pages headed by pList (connected by pDirty),
** this function notifies any active backup processes that the pages have
** changed. 
*/ 
static int pagerLogFrames(
  Pager *pPager,                  /* Pager object */
  PgHdr *pList,                   /* List of frames to log */
................................................................................
  Pgno nTruncate,                 /* Database size after this commit */
  int isCommit,                   /* True if this is a commit */
  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
){
  int rc;                         /* Return code */

  assert( pPager->pLog );
  rc = sqlite3LogFrames(pPager->pLog, 
      pPager->pageSize, pList, nTruncate, isCommit, sync_flags
  );
  if( rc==SQLITE_OK && pPager->pBackup ){
    PgHdr *p;
    for(p=pList; p; p=p->pDirty){
      sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
    }
................................................................................

static int pagerOpenSnapshot(Pager *pPager){
  int rc;                         /* Return code */
  int changed = 0;                /* True if cache must be reset */

  assert( pagerUseLog(pPager) );

  rc = sqlite3LogOpenSnapshot(pPager->pLog, &changed);
  if( rc==SQLITE_OK ){
    int dummy;
    if( changed ){
      pager_reset(pPager);
      assert( pPager->errCode || pPager->dbSizeValid==0 );
    }
    rc = sqlite3PagerPagecount(pPager, &dummy);
................................................................................

    if( pagerUseLog(pPager) ){
      /* Grab the write lock on the log file. If successful, upgrade to
      ** PAGER_EXCLUSIVE state. Otherwise, return an error code to the caller.
      ** The busy-handler is not invoked if another connection already
      ** holds the write-lock. If possible, the upper layer will call it.
      */
      rc = sqlite3LogWriteLock(pPager->pLog, 1);
      if( rc==SQLITE_OK ){
        pPager->dbOrigSize = pPager->dbSize;
        pPager->state = PAGER_RESERVED;
        pPager->journalOff = 0;
      }
    }else{
      /* Obtain a RESERVED lock on the database file. If the exFlag parameter
................................................................................
/*
** This function is called when the user invokes "PRAGMA checkpoint".
*/
int sqlite3PagerCheckpoint(Pager *pPager){
  int rc = SQLITE_OK;
  if( pPager->pLog ){
    u8 *zBuf = (u8 *)pPager->pTmpSpace;
    rc = sqlite3LogCheckpoint(pPager->pLog, pPager->fd, 
        (pPager->noSync ? 0 : pPager->sync_flags),
        zBuf, pPager->xBusyHandler, pPager->pBusyHandlerArg
    );
  }
  return rc;
}

int sqlite3PagerLogCallback(Pager *pPager){
  return sqlite3LogCallback(pPager->pLog);
}

/*
** Open a connection to the write-ahead log file for pager pPager. If
** the log connection is already open, this function is a no-op.
**
** The caller must be holding a SHARED lock on the database file to call
................................................................................
  assert( pPager->state>=PAGER_SHARED );
  if( !pPager->pLog ){

    /* Open the connection to the log file. If this operation fails, 
    ** (e.g. due to malloc() failure), unlock the database file and 
    ** return an error code.
    */
    rc = sqlite3LogOpen(pPager->pVfs, pPager->zFilename, &pPager->pLog);
    if( rc==SQLITE_OK ){
      pPager->journalMode = PAGER_JOURNALMODE_WAL;
    }
  }else{
    *pisOpen = 1;
  }

................................................................................
  if( !pPager->pLog ){
    int logexists = 0;
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_SHARED);
    if( rc==SQLITE_OK ){
      rc = pagerHasWAL(pPager, &logexists);
    }
    if( rc==SQLITE_OK && logexists ){
      rc = sqlite3LogOpen(pPager->pVfs, pPager->zFilename, &pPager->pLog);
    }
  }
    
  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
  ** the database file, the log and log-summary files will be deleted.
  */
  if( rc==SQLITE_OK && pPager->pLog ){
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_EXCLUSIVE);
    if( rc==SQLITE_OK ){
      rc = sqlite3LogClose(pPager->pLog, pPager->fd,
        (pPager->noSync ? 0 : pPager->sync_flags), 
        (u8*)pPager->pTmpSpace
      );
      pPager->pLog = 0;
    }
  }
  return rc;
}

#endif /* SQLITE_OMIT_DISKIO */

** 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.
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "wal.h"

/*
******************** NOTES ON THE DESIGN OF THE PAGER ************************
**
** Within this comment block, a page is deemed to have been synced
** automatically as soon as it is written when PRAGMA synchronous=OFF.
** Otherwise, the page is not synced until the xSync method of the VFS
................................................................................
    ** this happens.  One can argue that this doesn't need to be cleared
    ** until the change-counter check fails in PagerSharedLock().
    ** Clearing the page size cache here is being conservative.
    */
    pPager->dbSizeValid = 0;

    if( pagerUseLog(pPager) ){
      sqlite3WalCloseSnapshot(pPager->pLog);
    }else{
      rc = osUnlock(pPager->fd, NO_LOCK);
    }
    if( rc ){
      pPager->errCode = rc;
    }
    IOTRACE(("UNLOCK %p\n", pPager))
................................................................................
  }
  sqlite3BitvecDestroy(pPager->pInJournal);
  pPager->pInJournal = 0;
  pPager->nRec = 0;
  sqlite3PcacheCleanAll(pPager->pPCache);

  if( pagerUseLog(pPager) ){
    rc2 = sqlite3WalWriteLock(pPager->pLog, 0);
    pPager->state = PAGER_SHARED;
  }else if( !pPager->exclusiveMode ){
    rc2 = osUnlock(pPager->fd, SHARED_LOCK);
    pPager->state = PAGER_SHARED;
    pPager->changeCountDone = 0;
  }else if( pPager->state==PAGER_SYNCED ){
    pPager->state = PAGER_EXCLUSIVE;
................................................................................
    assert( pPager->tempFile );
    memset(pPg->pData, 0, pPager->pageSize);
    return SQLITE_OK;
  }

  if( pagerUseLog(pPager) ){
    /* Try to pull the page from the write-ahead log. */
    rc = sqlite3WalRead(pPager->pLog, pgno, &isInLog, pPg->pData);
  }
  if( rc==SQLITE_OK && !isInLog ){
    iOffset = (pgno-1)*(i64)pPager->pageSize;
    rc = sqlite3OsRead(pPager->fd, pPg->pData, pPager->pageSize, iOffset);
    if( rc==SQLITE_IOERR_SHORT_READ ){
      rc = SQLITE_OK;
    }
................................................................................
  ** updated as data is copied out of the rollback journal and into the
  ** database. This is not generally possible with a WAL database, as
  ** rollback involves simply truncating the log file. Therefore, if one
  ** or more frames have already been written to the log (and therefore 
  ** also copied into the backup databases) as part of this transaction,
  ** the backups must be restarted.
  */
  if( sqlite3WalDirty(pPager->pLog) ){
    sqlite3BackupRestart(pPager->pBackup);
  }

  /* For all pages in the cache that are currently dirty or have already
  ** been written (but not committed) to the log file, do one of the 
  ** following:
  **
  **   + Discard the cached page (if refcount==0), or
  **   + Reload page content from the database (if refcount>0).
  */
  pPager->dbSize = pPager->dbOrigSize;
  rc = sqlite3WalUndo(pPager->pLog, pagerUndoCallback, (void *)pPager);
  pList = sqlite3PcacheDirtyList(pPager->pPCache);
  while( pList && rc==SQLITE_OK ){
    PgHdr *pNext = pList->pDirty;
    rc = pagerUndoCallback((void *)pPager, pList->pgno);
    pList = pNext;
  }

................................................................................
  if( pPager->dbSizeValid ){
    nPage = pPager->dbSize;
  }else{
    int rc;                 /* Error returned by OsFileSize() */
    i64 n = 0;              /* File size in bytes returned by OsFileSize() */

    if( pagerUseLog(pPager) ){
      sqlite3WalDbsize(pPager->pLog, &nPage);
    }

    if( nPage==0 ){
      assert( isOpen(pPager->fd) || pPager->tempFile );
      if( isOpen(pPager->fd) ){
        if( SQLITE_OK!=(rc = sqlite3OsFileSize(pPager->fd, &n)) ){
          pager_error(pPager, rc);
................................................................................
int sqlite3PagerClose(Pager *pPager){
  u8 *pTmp = (u8 *)pPager->pTmpSpace;

  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  pPager->errCode = 0;
  pPager->exclusiveMode = 0;
  sqlite3WalClose(pPager->pLog, pPager->fd, 
    (pPager->noSync ? 0 : pPager->sync_flags), pTmp
  );
  pPager->pLog = 0;
  pager_reset(pPager);
  if( MEMDB ){
    pager_unlock(pPager);
  }else{
................................................................................
    assert( pPager->nSavepoint>0 );
    rc = addToSavepointBitvecs(pPager, pPg->pgno);
  }
  return rc;
}

/*
** This function is a wrapper around sqlite3WalFrames(). As well as logging
** the contents of the list of pages headed by pList (connected by pDirty),
** this function notifies any active backup processes that the pages have
** changed. 
*/ 
static int pagerLogFrames(
  Pager *pPager,                  /* Pager object */
  PgHdr *pList,                   /* List of frames to log */
................................................................................
  Pgno nTruncate,                 /* Database size after this commit */
  int isCommit,                   /* True if this is a commit */
  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
){
  int rc;                         /* Return code */

  assert( pPager->pLog );
  rc = sqlite3WalFrames(pPager->pLog, 
      pPager->pageSize, pList, nTruncate, isCommit, sync_flags
  );
  if( rc==SQLITE_OK && pPager->pBackup ){
    PgHdr *p;
    for(p=pList; p; p=p->pDirty){
      sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
    }
................................................................................

static int pagerOpenSnapshot(Pager *pPager){
  int rc;                         /* Return code */
  int changed = 0;                /* True if cache must be reset */

  assert( pagerUseLog(pPager) );

  rc = sqlite3WalOpenSnapshot(pPager->pLog, &changed);
  if( rc==SQLITE_OK ){
    int dummy;
    if( changed ){
      pager_reset(pPager);
      assert( pPager->errCode || pPager->dbSizeValid==0 );
    }
    rc = sqlite3PagerPagecount(pPager, &dummy);
................................................................................

    if( pagerUseLog(pPager) ){
      /* Grab the write lock on the log file. If successful, upgrade to
      ** PAGER_EXCLUSIVE state. Otherwise, return an error code to the caller.
      ** The busy-handler is not invoked if another connection already
      ** holds the write-lock. If possible, the upper layer will call it.
      */
      rc = sqlite3WalWriteLock(pPager->pLog, 1);
      if( rc==SQLITE_OK ){
        pPager->dbOrigSize = pPager->dbSize;
        pPager->state = PAGER_RESERVED;
        pPager->journalOff = 0;
      }
    }else{
      /* Obtain a RESERVED lock on the database file. If the exFlag parameter
................................................................................
/*
** This function is called when the user invokes "PRAGMA checkpoint".
*/
int sqlite3PagerCheckpoint(Pager *pPager){
  int rc = SQLITE_OK;
  if( pPager->pLog ){
    u8 *zBuf = (u8 *)pPager->pTmpSpace;
    rc = sqlite3WalCheckpoint(pPager->pLog, pPager->fd, 
        (pPager->noSync ? 0 : pPager->sync_flags),
        zBuf, pPager->xBusyHandler, pPager->pBusyHandlerArg
    );
  }
  return rc;
}

int sqlite3PagerLogCallback(Pager *pPager){
  return sqlite3WalCallback(pPager->pLog);
}

/*
** Open a connection to the write-ahead log file for pager pPager. If
** the log connection is already open, this function is a no-op.
**
** The caller must be holding a SHARED lock on the database file to call
................................................................................
  assert( pPager->state>=PAGER_SHARED );
  if( !pPager->pLog ){

    /* Open the connection to the log file. If this operation fails, 
    ** (e.g. due to malloc() failure), unlock the database file and 
    ** return an error code.
    */
    rc = sqlite3WalOpen(pPager->pVfs, pPager->zFilename, &pPager->pLog);
    if( rc==SQLITE_OK ){
      pPager->journalMode = PAGER_JOURNALMODE_WAL;
    }
  }else{
    *pisOpen = 1;
  }

................................................................................
  if( !pPager->pLog ){
    int logexists = 0;
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_SHARED);
    if( rc==SQLITE_OK ){
      rc = pagerHasWAL(pPager, &logexists);
    }
    if( rc==SQLITE_OK && logexists ){
      rc = sqlite3WalOpen(pPager->pVfs, pPager->zFilename, &pPager->pLog);
    }
  }
    
  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
  ** the database file, the log and log-summary files will be deleted.
  */
  if( rc==SQLITE_OK && pPager->pLog ){
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_EXCLUSIVE);
    if( rc==SQLITE_OK ){
      rc = sqlite3WalClose(pPager->pLog, pPager->fd,
        (pPager->noSync ? 0 : pPager->sync_flags), 
        (u8*)pPager->pTmpSpace
      );
      pPager->pLog = 0;
    }
  }
  return rc;
}

#endif /* SQLITE_OMIT_DISKIO */

** The fields in the log-summary file header are described in the comment 
** directly above the definition of struct LogSummaryHdr (see below). 
** Immediately following the fields in the LogSummaryHdr structure is
** an 8 byte checksum based on the contents of the header. This field is
** not the same as the iCheck1 and iCheck2 fields of the LogSummaryHdr.
*/

#include "log.h"

#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>

typedef struct LogSummaryHdr LogSummaryHdr;
typedef struct LogSummary LogSummary;
................................................................................
**
** A SHARED lock should be held on the database file when this function
** is called. The purpose of this SHARED lock is to prevent any other
** client from unlinking the log or log-summary file. If another process
** were to do this just after this client opened one of these files, the
** system would be badly broken.
*/
int sqlite3LogOpen(
  sqlite3_vfs *pVfs,              /* vfs module to open log file with */
  const char *zDb,                /* Name of database file */
  Log **ppLog                     /* OUT: Allocated Log handle */
){
  int rc = SQLITE_OK;             /* Return Code */
  Log *pRet;                      /* Object to allocate and return */
  LogSummary *pSummary = 0;       /* Summary object */
................................................................................
  logIteratorFree(pIter);
  return rc;
}

/*
** Close a connection to a log file.
*/
int sqlite3LogClose(
  Log *pLog,                      /* Log to close */
  sqlite3_file *pFd,              /* Database file */
  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */
  u8 *zBuf                        /* Buffer of at least page-size bytes */
){
  int rc = SQLITE_OK;
  if( pLog ){
................................................................................
**
** If this call obtains a new read-lock and the database contents have been
** modified since the most recent call to LogCloseSnapshot() on this Log
** connection, then *pChanged is set to 1 before returning. Otherwise, it 
** is left unmodified. This is used by the pager layer to determine whether 
** or not any cached pages may be safely reused.
*/
int sqlite3LogOpenSnapshot(Log *pLog, int *pChanged){
  int rc = SQLITE_OK;
  if( pLog->isLocked==0 ){
    int nAttempt;

    /* Obtain a snapshot-lock on the log-summary file. The procedure
    ** for obtaining the snapshot log is:
    **
................................................................................
    if( rc!=SQLITE_OK ){
      return rc;
    }

    rc = logSummaryReadHdr(pLog, pChanged);
    if( rc!=SQLITE_OK ){
      /* An error occured while attempting log recovery. */
      sqlite3LogCloseSnapshot(pLog);
    }
  }
  return rc;
}

/*
** Unlock the current snapshot.
*/
void sqlite3LogCloseSnapshot(Log *pLog){
  if( pLog->isLocked ){
    assert( pLog->isLocked==LOG_REGION_A || pLog->isLocked==LOG_REGION_D );
    logLockRegion(pLog, pLog->isLocked, LOG_UNLOCK);
  }
  pLog->isLocked = 0;
}

/* 
** Read a page from the log, if it is present. 
*/
int sqlite3LogRead(Log *pLog, Pgno pgno, int *pInLog, u8 *pOut){
  u32 iRead = 0;
  u32 *aData = pLog->pSummary->aData;
  int iFrame = (pLog->hdr.iLastPg & 0xFFFFFF00);

  assert( pLog->isLocked );

  /* Do a linear search of the unindexed block of page-numbers (if any) 
................................................................................
  return SQLITE_OK;
}


/* 
** Set *pPgno to the size of the database file (or zero, if unknown).
*/
void sqlite3LogDbsize(Log *pLog, Pgno *pPgno){
  assert( pLog->isLocked );
  *pPgno = pLog->hdr.nPage;
}

/* 
** This function returns SQLITE_OK if the caller may write to the database.
** Otherwise, if the caller is operating on a snapshot that has already
** been overwritten by another writer, SQLITE_BUSY is returned.
*/
int sqlite3LogWriteLock(Log *pLog, int op){
  assert( pLog->isLocked );
  if( op ){

    /* Obtain the writer lock */
    int rc = logLockRegion(pLog, LOG_REGION_C|LOG_REGION_D, LOG_WRLOCK);
    if( rc!=SQLITE_OK ){
      return rc;
................................................................................
** to the log since the start of the transaction. If the callback returns
** other than SQLITE_OK, it is not invoked again and the error code is
** returned to the caller.
**
** Otherwise, if the callback function does not return an error, this
** function returns SQLITE_OK.
*/
int sqlite3LogUndo(Log *pLog, int (*xUndo)(void *, Pgno), void *pUndoCtx){
  int rc = SQLITE_OK;
  Pgno iMax = pLog->hdr.iLastPg;
  Pgno iFrame;

  assert( pLog->isWriteLocked );
  logSummaryReadHdr(pLog, 0);
  for(iFrame=pLog->hdr.iLastPg+1; iFrame<=iMax && rc==SQLITE_OK; iFrame++){
................................................................................
  }
  return rc;
}

/* 
** Return true if data has been written but not committed to the log file. 
*/
int sqlite3LogDirty(Log *pLog){
  assert( pLog->isWriteLocked );
  return( pLog->hdr.iLastPg!=((LogSummaryHdr*)pLog->pSummary->aData)->iLastPg );
}

/* 
** Write a set of frames to the log. The caller must hold at least a
** RESERVED lock on the database file.
*/
int sqlite3LogFrames(
  Log *pLog,                      /* Log handle to write to */
  int nPgsz,                      /* Database page-size in bytes */
  PgHdr *pList,                   /* List of dirty pages to write */
  Pgno nTruncate,                 /* Database size after this commit */
  int isCommit,                   /* True if this is a commit */
  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
){
................................................................................
**
**   1. Wait for an EXCLUSIVE lock on regions B and C.
**   2. Wait for an EXCLUSIVE lock on region A.
**   3. Copy the contents of the log into the database file.
**   4. Zero the log-summary header (so new readers will ignore the log).
**   5. Drop the locks obtained in steps 1 and 2.
*/
int sqlite3LogCheckpoint(
  Log *pLog,                      /* Log connection */
  sqlite3_file *pFd,              /* File descriptor open on db file */
  int sync_flags,                 /* Flags to sync db file with (or 0) */
  u8 *zBuf,                       /* Temporary buffer to use */
  int (*xBusyHandler)(void *),    /* Pointer to busy-handler function */
  void *pBusyHandlerArg           /* Argument to pass to xBusyHandler */
){
................................................................................
  }

  /* Release the locks. */
  logLockRegion(pLog, LOG_REGION_A|LOG_REGION_B|LOG_REGION_C, LOG_UNLOCK);
  return rc;
}

int sqlite3LogCallback(Log *pLog){
  u32 ret = 0;
  if( pLog ){
    ret = pLog->iCallback;
    pLog->iCallback = 0;
  }
  return (int)ret;
}

** The fields in the log-summary file header are described in the comment 
** directly above the definition of struct LogSummaryHdr (see below). 
** Immediately following the fields in the LogSummaryHdr structure is
** an 8 byte checksum based on the contents of the header. This field is
** not the same as the iCheck1 and iCheck2 fields of the LogSummaryHdr.
*/

#include "wal.h"

#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>

typedef struct LogSummaryHdr LogSummaryHdr;
typedef struct LogSummary LogSummary;
................................................................................
**
** A SHARED lock should be held on the database file when this function
** is called. The purpose of this SHARED lock is to prevent any other
** client from unlinking the log or log-summary file. If another process
** were to do this just after this client opened one of these files, the
** system would be badly broken.
*/
int sqlite3WalOpen(
  sqlite3_vfs *pVfs,              /* vfs module to open log file with */
  const char *zDb,                /* Name of database file */
  Log **ppLog                     /* OUT: Allocated Log handle */
){
  int rc = SQLITE_OK;             /* Return Code */
  Log *pRet;                      /* Object to allocate and return */
  LogSummary *pSummary = 0;       /* Summary object */
................................................................................
  logIteratorFree(pIter);
  return rc;
}

/*
** Close a connection to a log file.
*/
int sqlite3WalClose(
  Log *pLog,                      /* Log to close */
  sqlite3_file *pFd,              /* Database file */
  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */
  u8 *zBuf                        /* Buffer of at least page-size bytes */
){
  int rc = SQLITE_OK;
  if( pLog ){
................................................................................
**
** If this call obtains a new read-lock and the database contents have been
** modified since the most recent call to LogCloseSnapshot() on this Log
** connection, then *pChanged is set to 1 before returning. Otherwise, it 
** is left unmodified. This is used by the pager layer to determine whether 
** or not any cached pages may be safely reused.
*/
int sqlite3WalOpenSnapshot(Log *pLog, int *pChanged){
  int rc = SQLITE_OK;
  if( pLog->isLocked==0 ){
    int nAttempt;

    /* Obtain a snapshot-lock on the log-summary file. The procedure
    ** for obtaining the snapshot log is:
    **
................................................................................
    if( rc!=SQLITE_OK ){
      return rc;
    }

    rc = logSummaryReadHdr(pLog, pChanged);
    if( rc!=SQLITE_OK ){
      /* An error occured while attempting log recovery. */
      sqlite3WalCloseSnapshot(pLog);
    }
  }
  return rc;
}

/*
** Unlock the current snapshot.
*/
void sqlite3WalCloseSnapshot(Log *pLog){
  if( pLog->isLocked ){
    assert( pLog->isLocked==LOG_REGION_A || pLog->isLocked==LOG_REGION_D );
    logLockRegion(pLog, pLog->isLocked, LOG_UNLOCK);
  }
  pLog->isLocked = 0;
}

/* 
** Read a page from the log, if it is present. 
*/
int sqlite3WalRead(Log *pLog, Pgno pgno, int *pInLog, u8 *pOut){
  u32 iRead = 0;
  u32 *aData = pLog->pSummary->aData;
  int iFrame = (pLog->hdr.iLastPg & 0xFFFFFF00);

  assert( pLog->isLocked );

  /* Do a linear search of the unindexed block of page-numbers (if any) 
................................................................................
  return SQLITE_OK;
}


/* 
** Set *pPgno to the size of the database file (or zero, if unknown).
*/
void sqlite3WalDbsize(Log *pLog, Pgno *pPgno){
  assert( pLog->isLocked );
  *pPgno = pLog->hdr.nPage;
}

/* 
** This function returns SQLITE_OK if the caller may write to the database.
** Otherwise, if the caller is operating on a snapshot that has already
** been overwritten by another writer, SQLITE_BUSY is returned.
*/
int sqlite3WalWriteLock(Log *pLog, int op){
  assert( pLog->isLocked );
  if( op ){

    /* Obtain the writer lock */
    int rc = logLockRegion(pLog, LOG_REGION_C|LOG_REGION_D, LOG_WRLOCK);
    if( rc!=SQLITE_OK ){
      return rc;
................................................................................
** to the log since the start of the transaction. If the callback returns
** other than SQLITE_OK, it is not invoked again and the error code is
** returned to the caller.
**
** Otherwise, if the callback function does not return an error, this
** function returns SQLITE_OK.
*/
int sqlite3WalUndo(Log *pLog, int (*xUndo)(void *, Pgno), void *pUndoCtx){
  int rc = SQLITE_OK;
  Pgno iMax = pLog->hdr.iLastPg;
  Pgno iFrame;

  assert( pLog->isWriteLocked );
  logSummaryReadHdr(pLog, 0);
  for(iFrame=pLog->hdr.iLastPg+1; iFrame<=iMax && rc==SQLITE_OK; iFrame++){
................................................................................
  }
  return rc;
}

/* 
** Return true if data has been written but not committed to the log file. 
*/
int sqlite3WalDirty(Log *pLog){
  assert( pLog->isWriteLocked );
  return( pLog->hdr.iLastPg!=((LogSummaryHdr*)pLog->pSummary->aData)->iLastPg );
}

/* 
** Write a set of frames to the log. The caller must hold at least a
** RESERVED lock on the database file.
*/
int sqlite3WalFrames(
  Log *pLog,                      /* Log handle to write to */
  int nPgsz,                      /* Database page-size in bytes */
  PgHdr *pList,                   /* List of dirty pages to write */
  Pgno nTruncate,                 /* Database size after this commit */
  int isCommit,                   /* True if this is a commit */
  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
){
................................................................................
**
**   1. Wait for an EXCLUSIVE lock on regions B and C.
**   2. Wait for an EXCLUSIVE lock on region A.
**   3. Copy the contents of the log into the database file.
**   4. Zero the log-summary header (so new readers will ignore the log).
**   5. Drop the locks obtained in steps 1 and 2.
*/
int sqlite3WalCheckpoint(
  Log *pLog,                      /* Log connection */
  sqlite3_file *pFd,              /* File descriptor open on db file */
  int sync_flags,                 /* Flags to sync db file with (or 0) */
  u8 *zBuf,                       /* Temporary buffer to use */
  int (*xBusyHandler)(void *),    /* Pointer to busy-handler function */
  void *pBusyHandlerArg           /* Argument to pass to xBusyHandler */
){
................................................................................
  }

  /* Release the locks. */
  logLockRegion(pLog, LOG_REGION_A|LOG_REGION_B|LOG_REGION_C, LOG_UNLOCK);
  return rc;
}

int sqlite3WalCallback(Log *pLog){
  u32 ret = 0;
  if( pLog ){
    ret = pLog->iCallback;
    pLog->iCallback = 0;
  }
  return (int)ret;
}

**
*************************************************************************
** This header file defines the interface to the write-ahead logging 
** system. Refer to the comments below and the header comment attached to 
** the implementation of each function in log.c for further details.
*/

#ifndef _LOG_H_
#define _LOG_H_

#include "sqliteInt.h"

/* Connection to a log file. There is one object of this type for each pager. */
typedef struct Log Log;

/* Open and close a connection to a log file. */
int sqlite3LogOpen(sqlite3_vfs*, const char *zDb, Log **ppLog);
int sqlite3LogClose(Log *pLog, sqlite3_file *pFd, int sync_flags, u8 *zBuf);

/* Used by readers to open (lock) and close (unlock) a snapshot. */
int sqlite3LogOpenSnapshot(Log *pLog, int *);
void sqlite3LogCloseSnapshot(Log *pLog);

/* Read a page from the log, if it is present. */
int sqlite3LogRead(Log *pLog, Pgno pgno, int *pInLog, u8 *pOut);
void sqlite3LogDbsize(Log *pLog, Pgno *pPgno);

/* Obtain or release the WRITER lock. */
int sqlite3LogWriteLock(Log *pLog, int op);

/* Undo any frames written (but not committed) to the log */
int sqlite3LogUndo(Log *pLog, int (*xUndo)(void *, Pgno), void *pUndoCtx);

/* Return true if data has been written but not committed to the log file. */
int sqlite3LogDirty(Log *pLog);

/* Write a frame or frames to the log. */
int sqlite3LogFrames(Log *pLog, int, PgHdr *, Pgno, int, int);

/* Copy pages from the log to the database file */ 
int sqlite3LogCheckpoint(
  Log *pLog,                      /* Log connection */
  sqlite3_file *pFd,              /* File descriptor open on db file */
  int sync_flags,                 /* Flags to sync db file with (or 0) */
  u8 *zBuf,                       /* Temporary buffer to use */
  int (*xBusyHandler)(void *),    /* Pointer to busy-handler function */
  void *pBusyHandlerArg           /* Argument to pass to xBusyHandler */
);

/* Return the value to pass to a log callback. Or 0 for no callback. */
int sqlite3LogCallback(Log *pLog);

#endif /* _LOG_H_ */

**
*************************************************************************
** This header file defines the interface to the write-ahead logging 
** system. Refer to the comments below and the header comment attached to 
** the implementation of each function in log.c for further details.
*/

#ifndef _WAL_H_
#define _WAL_H_

#include "sqliteInt.h"

/* Connection to a log file. There is one object of this type for each pager. */
typedef struct Log Log;

/* Open and close a connection to a log file. */
int sqlite3WalOpen(sqlite3_vfs*, const char *zDb, Log **ppLog);
int sqlite3WalClose(Log *pLog, sqlite3_file *pFd, int sync_flags, u8 *zBuf);

/* Used by readers to open (lock) and close (unlock) a snapshot. */
int sqlite3WalOpenSnapshot(Log *pLog, int *);
void sqlite3WalCloseSnapshot(Log *pLog);

/* Read a page from the log, if it is present. */
int sqlite3WalRead(Log *pLog, Pgno pgno, int *pInLog, u8 *pOut);
void sqlite3WalDbsize(Log *pLog, Pgno *pPgno);

/* Obtain or release the WRITER lock. */
int sqlite3WalWriteLock(Log *pLog, int op);

/* Undo any frames written (but not committed) to the log */
int sqlite3WalUndo(Log *pLog, int (*xUndo)(void *, Pgno), void *pUndoCtx);

/* Return true if data has been written but not committed to the log file. */
int sqlite3WalDirty(Log *pLog);

/* Write a frame or frames to the log. */
int sqlite3WalFrames(Log *pLog, int, PgHdr *, Pgno, int, int);

/* Copy pages from the log to the database file */ 
int sqlite3WalCheckpoint(
  Log *pLog,                      /* Log connection */
  sqlite3_file *pFd,              /* File descriptor open on db file */
  int sync_flags,                 /* Flags to sync db file with (or 0) */
  u8 *zBuf,                       /* Temporary buffer to use */
  int (*xBusyHandler)(void *),    /* Pointer to busy-handler function */
  void *pBusyHandlerArg           /* Argument to pass to xBusyHandler */
);

/* Return the value to pass to a log callback. Or 0 for no callback. */
int sqlite3WalCallback(Log *pLog);

#endif /* _WAL_H_ */

   fts3.h
   fts3Int.h
   fts3_hash.h
   fts3_tokenizer.h
   hash.h
   hwtime.h
   keywordhash.h
   log.h
   mutex.h
   opcodes.h
   os_common.h
   os.h
   os_os2.h
   pager.h
   parse.h
................................................................................
   sqlite3ext.h
   sqlite3.h
   sqliteicu.h
   sqliteInt.h
   sqliteLimit.h
   vdbe.h
   vdbeInt.h

} {
  set available_hdr($hdr) 1
}
set available_hdr(sqliteInt.h) 0

# 78 stars used for comment formatting.
set s78 \
................................................................................
   os_unix.c
   os_win.c

   bitvec.c
   pcache.c
   pcache1.c
   rowset.c
   log.c
   pager.c

   btmutex.c
   btree.c
   backup.c

   vdbemem.c

   fts3.h
   fts3Int.h
   fts3_hash.h
   fts3_tokenizer.h
   hash.h
   hwtime.h
   keywordhash.h

   mutex.h
   opcodes.h
   os_common.h
   os.h
   os_os2.h
   pager.h
   parse.h
................................................................................
   sqlite3ext.h
   sqlite3.h
   sqliteicu.h
   sqliteInt.h
   sqliteLimit.h
   vdbe.h
   vdbeInt.h
   wal.h
} {
  set available_hdr($hdr) 1
}
set available_hdr(sqliteInt.h) 0

# 78 stars used for comment formatting.
set s78 \
................................................................................
   os_unix.c
   os_win.c

   bitvec.c
   pcache.c
   pcache1.c
   rowset.c
   wal.c
   pager.c

   btmutex.c
   btree.c
   backup.c

   vdbemem.c