** how well the database resists damage due to OS crashes and power
** failures.  Level 1 is the same as asynchronous (no syncs() occur and
** there is a high probability of damage)  Level 2 is the default.  There
** is a very low but non-zero probability of damage.  Level 3 reduces the
** probability of damage to near zero but with a write performance reduction.
*/
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
int sqlite3BtreeSetSafetyLevel(Btree *p, int level, int fullSync){





  BtShared *pBt = p->pBt;
  assert( sqlite3_mutex_held(p->db->mutex) );

  sqlite3BtreeEnter(p);
  sqlite3PagerSetSafetyLevel(pBt->pPager, level, fullSync);
  sqlite3BtreeLeave(p);
  return SQLITE_OK;
}
#endif

/*
** Return TRUE if the given btree is set to safety level 1.  In other

** how well the database resists damage due to OS crashes and power
** failures.  Level 1 is the same as asynchronous (no syncs() occur and
** there is a high probability of damage)  Level 2 is the default.  There
** is a very low but non-zero probability of damage.  Level 3 reduces the
** probability of damage to near zero but with a write performance reduction.
*/
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
int sqlite3BtreeSetSafetyLevel(
  Btree *p,              /* The btree to set the safety level on */
  int level,             /* PRAGMA synchronous.  1=OFF, 2=NORMAL, 3=FULL */
  int fullSync,          /* PRAGMA fullfsync. */
  int ckptFullSync       /* PRAGMA checkpoint_fullfync */
){
  BtShared *pBt = p->pBt;
  assert( sqlite3_mutex_held(p->db->mutex) );
  assert( level>=1 && level<=3 );
  sqlite3BtreeEnter(p);
  sqlite3PagerSetSafetyLevel(pBt->pPager, level, fullSync, ckptFullSync);
  sqlite3BtreeLeave(p);
  return SQLITE_OK;
}
#endif

/*
** Return TRUE if the given btree is set to safety level 1.  In other

#define BTREE_NO_READLOCK   2  /* Omit readlocks on readonly files */
#define BTREE_MEMORY        4  /* This is an in-memory DB */
#define BTREE_SINGLE        8  /* The file contains at most 1 b-tree */
#define BTREE_UNORDERED    16  /* Use of a hash implementation is OK */

int sqlite3BtreeClose(Btree*);
int sqlite3BtreeSetCacheSize(Btree*,int);
int sqlite3BtreeSetSafetyLevel(Btree*,int,int);
int sqlite3BtreeSyncDisabled(Btree*);
int sqlite3BtreeSetPageSize(Btree *p, int nPagesize, int nReserve, int eFix);
int sqlite3BtreeGetPageSize(Btree*);
int sqlite3BtreeMaxPageCount(Btree*,int);
u32 sqlite3BtreeLastPage(Btree*);
int sqlite3BtreeSecureDelete(Btree*,int);
int sqlite3BtreeGetReserve(Btree*);

#define BTREE_NO_READLOCK   2  /* Omit readlocks on readonly files */
#define BTREE_MEMORY        4  /* This is an in-memory DB */
#define BTREE_SINGLE        8  /* The file contains at most 1 b-tree */
#define BTREE_UNORDERED    16  /* Use of a hash implementation is OK */

int sqlite3BtreeClose(Btree*);
int sqlite3BtreeSetCacheSize(Btree*,int);
int sqlite3BtreeSetSafetyLevel(Btree*,int,int,int);
int sqlite3BtreeSyncDisabled(Btree*);
int sqlite3BtreeSetPageSize(Btree *p, int nPagesize, int nReserve, int eFix);
int sqlite3BtreeGetPageSize(Btree*);
int sqlite3BtreeMaxPageCount(Btree*,int);
u32 sqlite3BtreeLastPage(Btree*);
int sqlite3BtreeSecureDelete(Btree*,int);
int sqlite3BtreeGetReserve(Btree*);

  sqlite3_vfs *pVfs;          /* OS functions to use for IO */
  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
  u8 journalMode;             /* One of the PAGER_JOURNALMODE_* values */
  u8 useJournal;              /* Use a rollback journal on this file */
  u8 noReadlock;              /* Do not bother to obtain readlocks */
  u8 noSync;                  /* Do not sync the journal if true */
  u8 fullSync;                /* Do extra syncs of the journal for robustness */

  u8 sync_flags;              /* One of SYNC_NORMAL or SYNC_FULL */
  u8 tempFile;                /* zFilename is a temporary file */
  u8 readOnly;                /* True for a read-only database */
  u8 memDb;                   /* True to inhibit all file I/O */

  /**************************************************************************
  ** The following block contains those class members that change during
  ** routine opertion.  Class members not in this block are either fixed
................................................................................
    if( doTruncate || iLimit==0 ){
      rc = sqlite3OsTruncate(pPager->jfd, 0);
    }else{
      static const char zeroHdr[28] = {0};
      rc = sqlite3OsWrite(pPager->jfd, zeroHdr, sizeof(zeroHdr), 0);
    }
    if( rc==SQLITE_OK && !pPager->noSync ){
      rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_DATAONLY|pPager->sync_flags);
    }

    /* At this point the transaction is committed but the write lock 
    ** is still held on the file. If there is a size limit configured for 
    ** the persistent journal and the journal file currently consumes more
    ** space than that limit allows for, truncate it now. There is no need
    ** to sync the file following this operation.
................................................................................
    zMaster = pPager->pTmpSpace;
    rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
    testcase( rc!=SQLITE_OK );
  }
  if( rc==SQLITE_OK && !pPager->noSync 
   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
  ){
    rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
  }
  if( rc==SQLITE_OK ){
    rc = pager_end_transaction(pPager, zMaster[0]!='\0');
    testcase( rc!=SQLITE_OK );
  }
  if( rc==SQLITE_OK && zMaster[0] && res ){
    /* If there was a master journal and this routine will return success,
................................................................................
** changed. 
*/ 
static int pagerWalFrames(
  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->pWal );
  rc = sqlite3WalFrames(pPager->pWal, 
      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);
    }
  }
................................................................................
**    FULL      The journal is synced twice before writes begin on the
**              database (with some additional information - the nRec field
**              of the journal header - being written in between the two
**              syncs).  If we assume that writing a
**              single disk sector is atomic, then this mode provides
**              assurance that the journal will not be corrupted to the
**              point of causing damage to the database during rollback.

















**
** Numeric values associated with these states are OFF==1, NORMAL=2,
** and FULL=3.
*/
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
void sqlite3PagerSetSafetyLevel(Pager *pPager, int level, int bFullFsync){






  pPager->noSync =  (level==1 || pPager->tempFile) ?1:0;
  pPager->fullSync = (level==3 && !pPager->tempFile) ?1:0;
  pPager->sync_flags = (bFullFsync?SQLITE_SYNC_FULL:SQLITE_SYNC_NORMAL);













}
#endif

/*
** The following global variable is incremented whenever the library
** attempts to open a temporary file.  This information is used for
** testing and analysis only.  
................................................................................
  u8 *pTmp = (u8 *)pPager->pTmpSpace;

  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  /* pPager->errCode = 0; */
  pPager->exclusiveMode = 0;
#ifndef SQLITE_OMIT_WAL
  sqlite3WalClose(pPager->pWal,
    (pPager->noSync ? 0 : pPager->sync_flags), 
    pPager->pageSize, pTmp
  );
  pPager->pWal = 0;
#endif
  pager_reset(pPager);
  if( MEMDB ){
    pager_unlock(pPager);
  }else{
    /* If it is open, sync the journal file before calling UnlockAndRollback.
................................................................................
        ** for garbage data to be appended to the file, the nRec field
        ** is populated with 0xFFFFFFFF when the journal header is written
        ** and never needs to be updated.
        */
        if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
          PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
          IOTRACE(("JSYNC %p\n", pPager))
          rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags);
          if( rc!=SQLITE_OK ) return rc;
        }
        IOTRACE(("JHDR %p %lld\n", pPager, pPager->journalHdr));
        rc = sqlite3OsWrite(
            pPager->jfd, zHeader, sizeof(zHeader), pPager->journalHdr
        );
        if( rc!=SQLITE_OK ) return rc;
      }
      if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
        PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
        IOTRACE(("JSYNC %p\n", pPager))
        rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags| 
          (pPager->sync_flags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
        );
        if( rc!=SQLITE_OK ) return rc;
      }

      pPager->journalHdr = pPager->journalOff;
      if( newHdr && 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
        pPager->nRec = 0;
................................................................................
  pPager->exclusiveMode = (u8)tempFile; 
  pPager->changeCountDone = pPager->tempFile;
  pPager->memDb = (u8)memDb;
  pPager->readOnly = (u8)readOnly;
  assert( useJournal || pPager->tempFile );
  pPager->noSync = pPager->tempFile;
  pPager->fullSync = pPager->noSync ?0:1;
  pPager->sync_flags = SQLITE_SYNC_NORMAL;

  /* pPager->pFirst = 0; */
  /* pPager->pFirstSynced = 0; */
  /* pPager->pLast = 0; */
  pPager->nExtra = (u16)nExtra;
  pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
  assert( isOpen(pPager->fd) || tempFile );
  setSectorSize(pPager);
................................................................................
    /* Release the page reference. */
    sqlite3PagerUnref(pPgHdr);
  }
  return rc;
}

/*
** Sync the pager file to disk. This is a no-op for in-memory files
** or pages with the Pager.noSync flag set.
**
** If successful, or called on a pager for which it is a no-op, this
** function returns SQLITE_OK. Otherwise, an IO error code is returned.
*/
int sqlite3PagerSync(Pager *pPager){
  int rc;                              /* Return code */
  assert( !MEMDB );
  if( pPager->noSync ){
    rc = SQLITE_OK;
  }else{
    rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
  }
  return rc;
}

/*
** This function may only be called while a write-transaction is active in
** rollback. If the connection is in WAL mode, this call is a no-op. 
................................................................................
    */
    sqlite3BackupRestart(pPager->pBackup);
  }else{
    if( pagerUseWal(pPager) ){
      PgHdr *pList = sqlite3PcacheDirtyList(pPager->pPCache);
      if( pList ){
        rc = pagerWalFrames(pPager, pList, pPager->dbSize, 1, 
            (pPager->fullSync ? pPager->sync_flags : 0)
        );
      }
      if( rc==SQLITE_OK ){
        sqlite3PcacheCleanAll(pPager->pPCache);
      }
    }else{
      /* The following block updates the change-counter. Exactly how it
................................................................................
        assert( pPager->eState==PAGER_WRITER_DBMOD );
        rc = pager_truncate(pPager, nNew);
        if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
      }
  
      /* Finally, sync the database file. */
      if( !pPager->noSync && !noSync ){
        rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
      }
      IOTRACE(("DBSYNC %p\n", pPager))
    }
  }

commit_phase_one_exit:
  if( rc==SQLITE_OK && !pagerUseWal(pPager) ){
................................................................................
/*
** This function is called when the user invokes "PRAGMA checkpoint".
*/
int sqlite3PagerCheckpoint(Pager *pPager){
  int rc = SQLITE_OK;
  if( pPager->pWal ){
    u8 *zBuf = (u8 *)pPager->pTmpSpace;
    rc = sqlite3WalCheckpoint(pPager->pWal,
        (pPager->noSync ? 0 : pPager->sync_flags),
        pPager->pageSize, zBuf
    );
  }
  return rc;
}

int sqlite3PagerWalCallback(Pager *pPager){
  return sqlite3WalCallback(pPager->pWal);
}
................................................................................
    
  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
  ** the database file, the log and log-summary files will be deleted.
  */
  if( rc==SQLITE_OK && pPager->pWal ){
    rc = pagerExclusiveLock(pPager);
    if( rc==SQLITE_OK ){
      rc = sqlite3WalClose(pPager->pWal,
          (pPager->noSync ? 0 : pPager->sync_flags), 
          pPager->pageSize, (u8*)pPager->pTmpSpace
      );
      pPager->pWal = 0;
    }
  }
  return rc;
}

#ifdef SQLITE_HAS_CODEC

  sqlite3_vfs *pVfs;          /* OS functions to use for IO */
  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
  u8 journalMode;             /* One of the PAGER_JOURNALMODE_* values */
  u8 useJournal;              /* Use a rollback journal on this file */
  u8 noReadlock;              /* Do not bother to obtain readlocks */
  u8 noSync;                  /* Do not sync the journal if true */
  u8 fullSync;                /* Do extra syncs of the journal for robustness */
  u8 ckptSyncFlags;           /* SYNC_NORMAL or SYNC_FULL for checkpoint */
  u8 syncFlags;               /* SYNC_NORMAL or SYNC_FULL otherwise */
  u8 tempFile;                /* zFilename is a temporary file */
  u8 readOnly;                /* True for a read-only database */
  u8 memDb;                   /* True to inhibit all file I/O */

  /**************************************************************************
  ** The following block contains those class members that change during
  ** routine opertion.  Class members not in this block are either fixed
................................................................................
    if( doTruncate || iLimit==0 ){
      rc = sqlite3OsTruncate(pPager->jfd, 0);
    }else{
      static const char zeroHdr[28] = {0};
      rc = sqlite3OsWrite(pPager->jfd, zeroHdr, sizeof(zeroHdr), 0);
    }
    if( rc==SQLITE_OK && !pPager->noSync ){
      rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_DATAONLY|pPager->syncFlags);
    }

    /* At this point the transaction is committed but the write lock 
    ** is still held on the file. If there is a size limit configured for 
    ** the persistent journal and the journal file currently consumes more
    ** space than that limit allows for, truncate it now. There is no need
    ** to sync the file following this operation.
................................................................................
    zMaster = pPager->pTmpSpace;
    rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
    testcase( rc!=SQLITE_OK );
  }
  if( rc==SQLITE_OK && !pPager->noSync 
   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
  ){
    rc = sqlite3OsSync(pPager->fd, pPager->syncFlags);
  }
  if( rc==SQLITE_OK ){
    rc = pager_end_transaction(pPager, zMaster[0]!='\0');
    testcase( rc!=SQLITE_OK );
  }
  if( rc==SQLITE_OK && zMaster[0] && res ){
    /* If there was a master journal and this routine will return success,
................................................................................
** changed. 
*/ 
static int pagerWalFrames(
  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 syncFlags                   /* Flags to pass to OsSync() (or 0) */
){
  int rc;                         /* Return code */

  assert( pPager->pWal );
  rc = sqlite3WalFrames(pPager->pWal, 
      pPager->pageSize, pList, nTruncate, isCommit, syncFlags
  );
  if( rc==SQLITE_OK && pPager->pBackup ){
    PgHdr *p;
    for(p=pList; p; p=p->pDirty){
      sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
    }
  }
................................................................................
**    FULL      The journal is synced twice before writes begin on the
**              database (with some additional information - the nRec field
**              of the journal header - being written in between the two
**              syncs).  If we assume that writing a
**              single disk sector is atomic, then this mode provides
**              assurance that the journal will not be corrupted to the
**              point of causing damage to the database during rollback.
**
** The above is for a rollback-journal mode.  For WAL mode, OFF continues
** to mean that no syncs ever occur.  NORMAL means that the WAL is synced
** prior to the start of checkpoint and that the database file is synced
** at the conclusion of the checkpoint if the entire content of the WAL
** was written back into the database.  But no sync operations occur for
** an ordinary commit in NORMAL mode with WAL.  FULL means that the WAL
** file is synced following each commit operation, in addition to the
** syncs associated with NORMAL.
**
** Do not confuse synchronous=FULL with SQLITE_SYNC_FULL.  The
** SQLITE_SYNC_FULL macro means to use the MacOSX-style full-fsync
** using fcntl(F_FULLFSYNC).  SQLITE_SYNC_NORMAL means to do an
** ordinary fsync() call.  There is no difference between SQLITE_SYNC_FULL
** and SQLITE_SYNC_NORMAL on platforms other than MacOSX.  But the
** synchronous=FULL versus synchronous=NORMAL setting determines when
** the xSync primitive is called and is relevant to all platforms.
**
** Numeric values associated with these states are OFF==1, NORMAL=2,
** and FULL=3.
*/
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
void sqlite3PagerSetSafetyLevel(
  Pager *pPager,        /* The pager to set safety level for */
  int level,            /* PRAGMA synchronous.  1=OFF, 2=NORMAL, 3=FULL */  
  int bFullFsync,       /* PRAGMA fullfsync */
  int bCkptFullFsync    /* PRAGMA checkpoint_fullfsync */
){
  assert( level>=1 && level<=3 );
  pPager->noSync =  (level==1 || pPager->tempFile) ?1:0;
  pPager->fullSync = (level==3 && !pPager->tempFile) ?1:0;

  if( pPager->noSync ){
    pPager->syncFlags = 0;
    pPager->ckptSyncFlags = 0;
  }else if( bFullFsync ){
    pPager->syncFlags = SQLITE_SYNC_FULL;
    pPager->ckptSyncFlags = SQLITE_SYNC_FULL;
  }else if( bCkptFullFsync ){
    pPager->syncFlags = SQLITE_SYNC_NORMAL;
    pPager->ckptSyncFlags = SQLITE_SYNC_FULL;
  }else{
    pPager->syncFlags = SQLITE_SYNC_NORMAL;
    pPager->ckptSyncFlags = SQLITE_SYNC_NORMAL;
  }
}
#endif

/*
** The following global variable is incremented whenever the library
** attempts to open a temporary file.  This information is used for
** testing and analysis only.  
................................................................................
  u8 *pTmp = (u8 *)pPager->pTmpSpace;

  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  /* pPager->errCode = 0; */
  pPager->exclusiveMode = 0;
#ifndef SQLITE_OMIT_WAL
  sqlite3WalClose(pPager->pWal, pPager->ckptSyncFlags, pPager->pageSize, pTmp);



  pPager->pWal = 0;
#endif
  pager_reset(pPager);
  if( MEMDB ){
    pager_unlock(pPager);
  }else{
    /* If it is open, sync the journal file before calling UnlockAndRollback.
................................................................................
        ** for garbage data to be appended to the file, the nRec field
        ** is populated with 0xFFFFFFFF when the journal header is written
        ** and never needs to be updated.
        */
        if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
          PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
          IOTRACE(("JSYNC %p\n", pPager))
          rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags);
          if( rc!=SQLITE_OK ) return rc;
        }
        IOTRACE(("JHDR %p %lld\n", pPager, pPager->journalHdr));
        rc = sqlite3OsWrite(
            pPager->jfd, zHeader, sizeof(zHeader), pPager->journalHdr
        );
        if( rc!=SQLITE_OK ) return rc;
      }
      if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
        PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
        IOTRACE(("JSYNC %p\n", pPager))
        rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags| 
          (pPager->syncFlags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
        );
        if( rc!=SQLITE_OK ) return rc;
      }

      pPager->journalHdr = pPager->journalOff;
      if( newHdr && 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
        pPager->nRec = 0;
................................................................................
  pPager->exclusiveMode = (u8)tempFile; 
  pPager->changeCountDone = pPager->tempFile;
  pPager->memDb = (u8)memDb;
  pPager->readOnly = (u8)readOnly;
  assert( useJournal || pPager->tempFile );
  pPager->noSync = pPager->tempFile;
  pPager->fullSync = pPager->noSync ?0:1;
  pPager->syncFlags = pPager->noSync ? 0 : SQLITE_SYNC_NORMAL;
  pPager->ckptSyncFlags = pPager->syncFlags;
  /* pPager->pFirst = 0; */
  /* pPager->pFirstSynced = 0; */
  /* pPager->pLast = 0; */
  pPager->nExtra = (u16)nExtra;
  pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
  assert( isOpen(pPager->fd) || tempFile );
  setSectorSize(pPager);
................................................................................
    /* Release the page reference. */
    sqlite3PagerUnref(pPgHdr);
  }
  return rc;
}

/*
** Sync the database file to disk. This is a no-op for in-memory databases
** or pages with the Pager.noSync flag set.
**
** If successful, or if called on a pager for which it is a no-op, this
** function returns SQLITE_OK. Otherwise, an IO error code is returned.
*/
int sqlite3PagerSync(Pager *pPager){
  int rc;                              /* Return code */
  assert( !MEMDB );
  if( pPager->noSync ){
    rc = SQLITE_OK;
  }else{
    rc = sqlite3OsSync(pPager->fd, pPager->syncFlags);
  }
  return rc;
}

/*
** This function may only be called while a write-transaction is active in
** rollback. If the connection is in WAL mode, this call is a no-op. 
................................................................................
    */
    sqlite3BackupRestart(pPager->pBackup);
  }else{
    if( pagerUseWal(pPager) ){
      PgHdr *pList = sqlite3PcacheDirtyList(pPager->pPCache);
      if( pList ){
        rc = pagerWalFrames(pPager, pList, pPager->dbSize, 1, 
            (pPager->fullSync ? pPager->syncFlags : 0)
        );
      }
      if( rc==SQLITE_OK ){
        sqlite3PcacheCleanAll(pPager->pPCache);
      }
    }else{
      /* The following block updates the change-counter. Exactly how it
................................................................................
        assert( pPager->eState==PAGER_WRITER_DBMOD );
        rc = pager_truncate(pPager, nNew);
        if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
      }
  
      /* Finally, sync the database file. */
      if( !pPager->noSync && !noSync ){
        rc = sqlite3OsSync(pPager->fd, pPager->syncFlags);
      }
      IOTRACE(("DBSYNC %p\n", pPager))
    }
  }

commit_phase_one_exit:
  if( rc==SQLITE_OK && !pagerUseWal(pPager) ){
................................................................................
/*
** This function is called when the user invokes "PRAGMA checkpoint".
*/
int sqlite3PagerCheckpoint(Pager *pPager){
  int rc = SQLITE_OK;
  if( pPager->pWal ){
    u8 *zBuf = (u8 *)pPager->pTmpSpace;
    rc = sqlite3WalCheckpoint(pPager->pWal, pPager->ckptSyncFlags,

                              pPager->pageSize, zBuf);

  }
  return rc;
}

int sqlite3PagerWalCallback(Pager *pPager){
  return sqlite3WalCallback(pPager->pWal);
}
................................................................................
    
  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
  ** the database file, the log and log-summary files will be deleted.
  */
  if( rc==SQLITE_OK && pPager->pWal ){
    rc = pagerExclusiveLock(pPager);
    if( rc==SQLITE_OK ){
      rc = sqlite3WalClose(pPager->pWal, pPager->ckptSyncFlags,

                           pPager->pageSize, (u8*)pPager->pTmpSpace);

      pPager->pWal = 0;
    }
  }
  return rc;
}

#ifdef SQLITE_HAS_CODEC

int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);

/* Functions used to configure a Pager object. */
void sqlite3PagerSetBusyhandler(Pager*, int(*)(void *), void *);
int sqlite3PagerSetPagesize(Pager*, u32*, int);
int sqlite3PagerMaxPageCount(Pager*, int);
void sqlite3PagerSetCachesize(Pager*, int);
void sqlite3PagerSetSafetyLevel(Pager*,int,int);
int sqlite3PagerLockingMode(Pager *, int);
int sqlite3PagerSetJournalMode(Pager *, int);
int sqlite3PagerGetJournalMode(Pager*);
int sqlite3PagerOkToChangeJournalMode(Pager*);
i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
sqlite3_backup **sqlite3PagerBackupPtr(Pager*);

int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);

/* Functions used to configure a Pager object. */
void sqlite3PagerSetBusyhandler(Pager*, int(*)(void *), void *);
int sqlite3PagerSetPagesize(Pager*, u32*, int);
int sqlite3PagerMaxPageCount(Pager*, int);
void sqlite3PagerSetCachesize(Pager*, int);
void sqlite3PagerSetSafetyLevel(Pager*,int,int,int);
int sqlite3PagerLockingMode(Pager *, int);
int sqlite3PagerSetJournalMode(Pager *, int);
int sqlite3PagerGetJournalMode(Pager*);
int sqlite3PagerOkToChangeJournalMode(Pager*);
i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
sqlite3_backup **sqlite3PagerBackupPtr(Pager*);

  } aPragma[] = {
    { "full_column_names",        SQLITE_FullColNames  },
    { "short_column_names",       SQLITE_ShortColNames },
    { "count_changes",            SQLITE_CountRows     },
    { "empty_result_callbacks",   SQLITE_NullCallback  },
    { "legacy_file_format",       SQLITE_LegacyFileFmt },
    { "fullfsync",                SQLITE_FullFSync     },

    { "reverse_unordered_selects", SQLITE_ReverseOrder  },
#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
    { "automatic_index",          SQLITE_AutoIndex     },
#endif
#ifdef SQLITE_DEBUG
    { "sql_trace",                SQLITE_SqlTrace      },
    { "vdbe_listing",             SQLITE_VdbeListing   },
................................................................................
  /*
  ** Reset the safety level, in case the fullfsync flag or synchronous
  ** setting changed.
  */
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
  if( db->autoCommit ){
    sqlite3BtreeSetSafetyLevel(pDb->pBt, pDb->safety_level,
               (db->flags&SQLITE_FullFSync)!=0);

  }
#endif
pragma_out:
  sqlite3DbFree(db, zLeft);
  sqlite3DbFree(db, zRight);
}

#endif /* SQLITE_OMIT_PRAGMA */

  } aPragma[] = {
    { "full_column_names",        SQLITE_FullColNames  },
    { "short_column_names",       SQLITE_ShortColNames },
    { "count_changes",            SQLITE_CountRows     },
    { "empty_result_callbacks",   SQLITE_NullCallback  },
    { "legacy_file_format",       SQLITE_LegacyFileFmt },
    { "fullfsync",                SQLITE_FullFSync     },
    { "checkpoint_fullfsync",     SQLITE_CkptFullFSync },
    { "reverse_unordered_selects", SQLITE_ReverseOrder  },
#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
    { "automatic_index",          SQLITE_AutoIndex     },
#endif
#ifdef SQLITE_DEBUG
    { "sql_trace",                SQLITE_SqlTrace      },
    { "vdbe_listing",             SQLITE_VdbeListing   },
................................................................................
  /*
  ** Reset the safety level, in case the fullfsync flag or synchronous
  ** setting changed.
  */
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
  if( db->autoCommit ){
    sqlite3BtreeSetSafetyLevel(pDb->pBt, pDb->safety_level,
               (db->flags&SQLITE_FullFSync)!=0,
               (db->flags&SQLITE_CkptFullFSync)!=0);
  }
#endif
pragma_out:
  sqlite3DbFree(db, zLeft);
  sqlite3DbFree(db, zRight);
}

#endif /* SQLITE_OMIT_PRAGMA */

**
** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
** sync operation only needs to flush data to mass storage.  Inode
** information need not be flushed. If the lower four bits of the flag
** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
** If the lower four bits equal SQLITE_SYNC_FULL, that means
** to use Mac OS X style fullsync instead of fsync().












*/
#define SQLITE_SYNC_NORMAL        0x00002
#define SQLITE_SYNC_FULL          0x00003
#define SQLITE_SYNC_DATAONLY      0x00010

/*
** CAPI3REF: OS Interface Open File Handle
................................................................................
*/
#define SQLITE_FCNTL_LOCKSTATE        1
#define SQLITE_GET_LOCKPROXYFILE      2
#define SQLITE_SET_LOCKPROXYFILE      3
#define SQLITE_LAST_ERRNO             4
#define SQLITE_FCNTL_SIZE_HINT        5
#define SQLITE_FCNTL_CHUNK_SIZE       6



/*
** CAPI3REF: Mutex Handle
**
** The mutex module within SQLite defines [sqlite3_mutex] to be an
** abstract type for a mutex object.  The SQLite core never looks
** at the internal representation of an [sqlite3_mutex].  It only
................................................................................

/*
** CAPI3REF: Low-Level Control Of Database Files
**
** ^The [sqlite3_file_control()] interface makes a direct call to the
** xFileControl method for the [sqlite3_io_methods] object associated
** with a particular database identified by the second argument. ^The
** name of the database "main" for the main database or "temp" for the
** TEMP database, or the name that appears after the AS keyword for
** databases that are added using the [ATTACH] SQL command.
** ^A NULL pointer can be used in place of "main" to refer to the
** main database file.
** ^The third and fourth parameters to this routine
** are passed directly through to the second and third parameters of
** the xFileControl method.  ^The return value of the xFileControl
** method becomes the return value of this routine.






**
** ^If the second parameter (zDbName) does not match the name of any
** open database file, then SQLITE_ERROR is returned.  ^This error
** code is not remembered and will not be recalled by [sqlite3_errcode()]
** or [sqlite3_errmsg()].  The underlying xFileControl method might
** also return SQLITE_ERROR.  There is no way to distinguish between
** an incorrect zDbName and an SQLITE_ERROR return from the underlying

**
** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
** sync operation only needs to flush data to mass storage.  Inode
** information need not be flushed. If the lower four bits of the flag
** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
** If the lower four bits equal SQLITE_SYNC_FULL, that means
** to use Mac OS X style fullsync instead of fsync().
**
** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
** settings.  The [synchronous pragma] determines when calls to the
** xSync VFS method occur and applies uniformly across all platforms.
** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
** energetic or rigorous or forceful the sync operations are and
** only make a difference on Mac OSX for the default SQLite code.
** (Third-party VFS implementations might also make the distinction
** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
** operating systems natively supported by SQLite, only Mac OSX
** cares about the difference.)
*/
#define SQLITE_SYNC_NORMAL        0x00002
#define SQLITE_SYNC_FULL          0x00003
#define SQLITE_SYNC_DATAONLY      0x00010

/*
** CAPI3REF: OS Interface Open File Handle
................................................................................
*/
#define SQLITE_FCNTL_LOCKSTATE        1
#define SQLITE_GET_LOCKPROXYFILE      2
#define SQLITE_SET_LOCKPROXYFILE      3
#define SQLITE_LAST_ERRNO             4
#define SQLITE_FCNTL_SIZE_HINT        5
#define SQLITE_FCNTL_CHUNK_SIZE       6
#define SQLITE_FCNTL_FILE_POINTER     7


/*
** CAPI3REF: Mutex Handle
**
** The mutex module within SQLite defines [sqlite3_mutex] to be an
** abstract type for a mutex object.  The SQLite core never looks
** at the internal representation of an [sqlite3_mutex].  It only
................................................................................

/*
** CAPI3REF: Low-Level Control Of Database Files
**
** ^The [sqlite3_file_control()] interface makes a direct call to the
** xFileControl method for the [sqlite3_io_methods] object associated
** with a particular database identified by the second argument. ^The
** name of the database is "main" for the main database or "temp" for the
** TEMP database, or the name that appears after the AS keyword for
** databases that are added using the [ATTACH] SQL command.
** ^A NULL pointer can be used in place of "main" to refer to the
** main database file.
** ^The third and fourth parameters to this routine
** are passed directly through to the second and third parameters of
** the xFileControl method.  ^The return value of the xFileControl
** method becomes the return value of this routine.
**
** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
** a pointer to the underlying [sqlite3_file] object to be written into
** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
** case is a short-circuit path which does not actually invoke the
** underlying sqlite3_io_methods.xFileControl method.
**
** ^If the second parameter (zDbName) does not match the name of any
** open database file, then SQLITE_ERROR is returned.  ^This error
** code is not remembered and will not be recalled by [sqlite3_errcode()]
** or [sqlite3_errmsg()].  The underlying xFileControl method might
** also return SQLITE_ERROR.  There is no way to distinguish between
** an incorrect zDbName and an SQLITE_ERROR return from the underlying

#define SQLITE_WriteSchema    0x00010000  /* OK to update SQLITE_MASTER */
#define SQLITE_NoReadlock     0x00020000  /* Readlocks are omitted when 
                                          ** accessing read-only databases */
#define SQLITE_IgnoreChecks   0x00040000  /* Do not enforce check constraints */
#define SQLITE_ReadUncommitted 0x0080000  /* For shared-cache mode */
#define SQLITE_LegacyFileFmt  0x00100000  /* Create new databases in format 1 */
#define SQLITE_FullFSync      0x00200000  /* Use full fsync on the backend */
#define SQLITE_LoadExtension  0x00400000  /* Enable load_extension */
#define SQLITE_RecoveryMode   0x00800000  /* Ignore schema errors */
#define SQLITE_ReverseOrder   0x01000000  /* Reverse unordered SELECTs */
#define SQLITE_RecTriggers    0x02000000  /* Enable recursive triggers */
#define SQLITE_ForeignKeys    0x04000000  /* Enforce foreign key constraints  */
#define SQLITE_AutoIndex      0x08000000  /* Enable automatic indexes */
#define SQLITE_PreferBuiltin  0x10000000  /* Preference to built-in funcs */


/*
** Bits of the sqlite3.flags field that are used by the
** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface.
** These must be the low-order bits of the flags field.
*/
#define SQLITE_QueryFlattener 0x01        /* Disable query flattening */

#define SQLITE_WriteSchema    0x00010000  /* OK to update SQLITE_MASTER */
#define SQLITE_NoReadlock     0x00020000  /* Readlocks are omitted when 
                                          ** accessing read-only databases */
#define SQLITE_IgnoreChecks   0x00040000  /* Do not enforce check constraints */
#define SQLITE_ReadUncommitted 0x0080000  /* For shared-cache mode */
#define SQLITE_LegacyFileFmt  0x00100000  /* Create new databases in format 1 */
#define SQLITE_FullFSync      0x00200000  /* Use full fsync on the backend */
#define SQLITE_CkptFullFSync  0x00400000  /* Use full fsync for checkpoint */
#define SQLITE_RecoveryMode   0x00800000  /* Ignore schema errors */
#define SQLITE_ReverseOrder   0x01000000  /* Reverse unordered SELECTs */
#define SQLITE_RecTriggers    0x02000000  /* Enable recursive triggers */
#define SQLITE_ForeignKeys    0x04000000  /* Enforce foreign key constraints  */
#define SQLITE_AutoIndex      0x08000000  /* Enable automatic indexes */
#define SQLITE_PreferBuiltin  0x10000000  /* Preference to built-in funcs */
#define SQLITE_LoadExtension  0x20000000  /* Enable load_extension */

/*
** Bits of the sqlite3.flags field that are used by the
** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface.
** These must be the low-order bits of the flags field.
*/
#define SQLITE_QueryFlattener 0x01        /* Disable query flattening */