SQLite

         bitvec.o btmutex.o btree.o build.o \
         callback.o complete.o date.o delete.o expr.o fault.o \
         fts3.o fts3_hash.o fts3_icu.o fts3_porter.o \
         fts3_tokenizer.o fts3_tokenizer1.o \
         func.o global.o hash.o \
         icu.o insert.o journal.o legacy.o loadext.o \
         main.o malloc.o mem1.o mem2.o mem3.o mem4.o mem5.o mem6.o \

         mutex.o mutex_noop.o mutex_os2.o mutex_unix.o mutex_w32.o \
         opcodes.o os.o os_os2.o os_unix.o os_win.o \
         pager.o parse.o pcache.o pragma.o prepare.o printf.o \
         random.o resolve.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 vdbefifo.o vdbemem.o \

  $(TOP)/src/malloc.c \
  $(TOP)/src/mem1.c \
  $(TOP)/src/mem2.c \
  $(TOP)/src/mem3.c \
  $(TOP)/src/mem4.c \
  $(TOP)/src/mem5.c \
  $(TOP)/src/mem6.c \

  $(TOP)/src/mutex.c \
  $(TOP)/src/mutex.h \
  $(TOP)/src/mutex_noop.c \
  $(TOP)/src/mutex_os2.c \
  $(TOP)/src/mutex_unix.c \
  $(TOP)/src/mutex_w32.c \
  $(TOP)/src/os.c \

** 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 1.497 2008/10/07 11:51:20 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/

/*
** Return true if page *pPg has already been written to the statement
** journal (or statement snapshot has been created, if *pPg is part
** of an in-memory database).
*/
static int pageInStatement(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  if( MEMDB ){
    return pPg->apSave[1]!=0;
  }else{
    return sqlite3BitvecTest(pPager->pInStmt, pPg->pgno);
  }
}

/*
** Read a 32-bit integer from the given file descriptor.  Store the integer
** that is read in *pRes.  Return SQLITE_OK if everything worked, or an
** error code is something goes wrong.
**

** The CHECK_PAGE macro takes a PgHdr* as an argument. If SQLITE_CHECK_PAGES
** is defined, and NDEBUG is not defined, an assert() statement checks
** that the page is either dirty or still matches the calculated page-hash.
*/
#define CHECK_PAGE(x) checkPage(x)
static void checkPage(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  assert( !pPg->pageHash || pPager->errCode || MEMDB 
      || (pPg->flags&PGHDR_DIRTY) || pPg->pageHash==pager_pagehash(pPg) );
}

#else
#define pager_datahash(X,Y)  0
#define pager_pagehash(X)  0
#define CHECK_PAGE(x)

  **   * When the pager is in no-sync mode. Corruption can follow a
  **     power failure in this case anyway.
  **
  **   * When the SQLITE_IOCAP_SAFE_APPEND flag is set. This guarantees
  **     that garbage data is never appended to the journal file.
  */
  assert(pPager->fd->pMethods||pPager->noSync);
  if( (pPager->noSync) 
   || (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND) 
  ){
    put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
  }else{
    put32bits(&zHeader[sizeof(aJournalMagic)], 0);
  }

  int len; 
  int i; 
  i64 jrnlOff;
  i64 jrnlSize;
  u32 cksum = 0;
  char zBuf[sizeof(aJournalMagic)+2*4];

  if( !zMaster || pPager->setMaster) return SQLITE_OK;

  pPager->setMaster = 1;

  len = strlen(zMaster);
  for(i=0; i<len; i++){
    cksum += zMaster[i];
  }

** the cache and reset the Pager structure internal state. If there is
** an open journal-file, then the next time a shared-lock is obtained
** on the pager file (by this or any other process), it will be
** treated as a hot-journal and rolled back.
*/
static void pager_unlock(Pager *pPager){
  if( !pPager->exclusiveMode ){
    if( !MEMDB ){
      int rc = osUnlock(pPager->fd, NO_LOCK);
      if( rc ) pPager->errCode = rc;
      pPager->dbSize = -1;
      IOTRACE(("UNLOCK %p\n", pPager))

      /* Always close the journal file when dropping the database lock.
      ** Otherwise, another connection with journal_mode=delete might
      ** delete the file out from under us.
      */
      if( pPager->journalOpen ){
        sqlite3OsClose(pPager->jfd);
        pPager->journalOpen = 0;
        sqlite3BitvecDestroy(pPager->pInJournal);
        pPager->pInJournal = 0;
        sqlite3BitvecDestroy(pPager->pAlwaysRollback);
        pPager->pAlwaysRollback = 0;
      }

      /* If Pager.errCode is set, the contents of the pager cache cannot be
      ** trusted. Now that the pager file is unlocked, the contents of the
      ** cache can be discarded and the error code safely cleared.
      */
      if( pPager->errCode ){
        if( rc==SQLITE_OK ) pPager->errCode = SQLITE_OK;
        pager_reset(pPager);
        if( pPager->stmtOpen ){
          sqlite3OsClose(pPager->stfd);
          sqlite3BitvecDestroy(pPager->pInStmt);
          pPager->pInStmt = 0;
        }
        pPager->stmtOpen = 0;
        pPager->stmtInUse = 0;
        pPager->journalOff = 0;
        pPager->journalStarted = 0;
        pPager->stmtAutoopen = 0;
        pPager->origDbSize = 0;
      }
    }

    if( !MEMDB || pPager->errCode==SQLITE_OK ){
      pPager->state = PAGER_UNLOCK;
      pPager->changeCountDone = 0;
    }
  }
}

/*
** Execute a rollback if a transaction is active and unlock the 
** database file. If the pager has already entered the error state, 
** do not attempt the rollback.

** TODO: Consider keeping the journal file open for temporary databases.
** This might give a performance improvement on windows where opening
** a file is an expensive operation.
*/
static int pager_end_transaction(Pager *pPager, int hasMaster){
  int rc = SQLITE_OK;
  int rc2 = SQLITE_OK;
  assert( !MEMDB );
  if( pPager->state<PAGER_RESERVED ){
    return SQLITE_OK;
  }
  sqlite3PagerStmtCommit(pPager);
  if( pPager->stmtOpen && !pPager->exclusiveMode ){
    sqlite3OsClose(pPager->stfd);
    pPager->stmtOpen = 0;
  }
  if( pPager->journalOpen ){
    if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE







         && (rc = sqlite3OsTruncate(pPager->jfd, 0))==SQLITE_OK ){
      pPager->journalOff = 0;
      pPager->journalStarted = 0;
    }else if( pPager->exclusiveMode 
     || pPager->journalMode==PAGER_JOURNALMODE_PERSIST
    ){
      rc = zeroJournalHdr(pPager, hasMaster);

  }else if( pPager->state==PAGER_SYNCED ){
    pPager->state = PAGER_EXCLUSIVE;
  }
  pPager->origDbSize = 0;
  pPager->setMaster = 0;
  pPager->needSync = 0;
  /* lruListSetFirstSynced(pPager); */

  pPager->dbSize = -1;

  pPager->dbModified = 0;

  return (rc==SQLITE_OK?rc2:rc);
}

/*
** Compute and return a checksum for the page of data.

**              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 || MEMDB;
  pPager->fullSync = level==3 && !pPager->tempFile;
  pPager->sync_flags = (bFullFsync?SQLITE_SYNC_FULL:SQLITE_SYNC_NORMAL);
  if( pPager->noSync ) pPager->needSync = 0;
}
#endif

/*

  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;
  int journalFileSize = sqlite3JournalSize(pVfs);
  int pcacheSize = sqlite3PcacheSize();
  int szPageDflt = SQLITE_DEFAULT_PAGE_SIZE;
  char *zPathname = 0;
  int nPathname = 0;







  /* The default return is a NULL pointer */
  *ppPager = 0;

  /* Compute and store the full pathname in an allocated buffer pointed
  ** to by zPathname, length nPathname. Or, if this is a temporary file,
  ** leave both nPathname and zPathname set to 0.
  */
  if( zFilename && zFilename[0] ){
    nPathname = pVfs->mxPathname+1;
    zPathname = sqlite3Malloc(nPathname*2);
    if( zPathname==0 ){
      return SQLITE_NOMEM;
    }
#ifndef SQLITE_OMIT_MEMORYDB
    if( strcmp(zFilename,":memory:")==0 ){
      memDb = 1;
      zPathname[0] = 0;
      useJournal = 0;
    }else
#endif
    {
      rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
    }
    if( rc!=SQLITE_OK ){
      sqlite3_free(zPathname);
      return rc;
    }
    nPathname = strlen(zPathname);
  }

  /* Allocate memory for the pager structure */
  pPager = sqlite3MallocZero(
    sizeof(*pPager) +           /* Pager structure */
    pcacheSize      +           /* PCache object */
    journalFileSize +           /* The journal file structure */ 

    pVfs->szOsFile * 3 +        /* The main db and two journal files */ 
    3*nPathname + 40            /* zFilename, zDirectory, zJournal */
  );
  if( !pPager ){
    sqlite3_free(zPathname);
    return SQLITE_NOMEM;
  }
  pPager->pPCache = (PCache *)&pPager[1];
  pPtr = ((u8 *)&pPager[1]) + pcacheSize;
  pPager->vfsFlags = vfsFlags;
  pPager->fd = (sqlite3_file*)&pPtr[pVfs->szOsFile*0];
  pPager->stfd = (sqlite3_file*)&pPtr[pVfs->szOsFile*1];
  pPager->jfd = (sqlite3_file*)&pPtr[pVfs->szOsFile*2];
  pPager->zFilename = (char*)&pPtr[pVfs->szOsFile*2+journalFileSize];
  pPager->zDirectory = &pPager->zFilename[nPathname+1];
  pPager->zJournal = &pPager->zDirectory[nPathname+1];
  pPager->pVfs = pVfs;
  if( zPathname ){
    memcpy(pPager->zFilename, zPathname, nPathname+1);
    sqlite3_free(zPathname);
  }

        }
#endif
        if( szPageDflt>SQLITE_MAX_DEFAULT_PAGE_SIZE ){
          szPageDflt = SQLITE_MAX_DEFAULT_PAGE_SIZE;
        }
      }
    }
  }else if( !memDb ){
    /* If a temporary file is requested, it is not opened immediately.
    ** In this case we accept the default page size and delay actually
    ** opening the file until the first call to OsWrite().




    */ 
    tempFile = 1;
    pPager->state = PAGER_EXCLUSIVE;
  }

  if( pPager && rc==SQLITE_OK ){
    pPager->pTmpSpace = sqlite3PageMalloc(szPageDflt);

  pPager->fullSync = (pPager->noSync?0:1);
  pPager->sync_flags = SQLITE_SYNC_NORMAL;
  /* pPager->pFirst = 0; */
  /* pPager->pFirstSynced = 0; */
  /* pPager->pLast = 0; */
  pPager->nExtra = nExtra;
  pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
  assert(pPager->fd->pMethods||memDb||tempFile);
  if( !memDb ){
    setSectorSize(pPager);


  }
  /* pPager->pBusyHandler = 0; */
  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
  *ppPager = pPager;
  return SQLITE_OK;
}

** these cases sqlite3OsRead() will return an error, to which the correct 
** response is to zero the memory at pDest and continue.  A real IO error 
** will presumably recur and be picked up later (Todo: Think about this).
*/
int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
  int rc = SQLITE_OK;
  memset(pDest, 0, N);
  assert(MEMDB||pPager->fd->pMethods||pPager->tempFile);
  if( pPager->fd->pMethods ){
    IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
    rc = sqlite3OsRead(pPager->fd, pDest, N, 0);
    if( rc==SQLITE_IOERR_SHORT_READ ){
      rc = SQLITE_OK;
    }
  }

  /* The OS lock values must be the same as the Pager lock values */
  assert( PAGER_SHARED==SHARED_LOCK );
  assert( PAGER_RESERVED==RESERVED_LOCK );
  assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );

  /* If the file is currently unlocked then the size must be unknown */
  assert( pPager->state>=PAGER_SHARED || pPager->dbSize<0 || MEMDB );

  if( pPager->state>=locktype ){
    rc = SQLITE_OK;
  }else{
    if( pPager->pBusyHandler ) pPager->pBusyHandler->nBusy = 0;
    do {
      rc = sqlite3OsLock(pPager->fd, locktype);

}

/*
** Truncate the file to the number of pages specified.
*/
int sqlite3PagerTruncate(Pager *pPager, Pgno nPage){
  int rc = SQLITE_OK;
  assert( pPager->state>=PAGER_SHARED || MEMDB );


  sqlite3PagerPagecount(pPager, 0);
  if( pPager->errCode ){
    rc = pPager->errCode;
  }else if( nPage<(unsigned)pPager->dbSize ){
    if( MEMDB ){
      pPager->dbSize = nPage;
      pager_truncate_cache(pPager);
    }else{
      rc = syncJournal(pPager);
      if( rc==SQLITE_OK ){
        /* Get an exclusive lock on the database before truncating. */
        rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
      }
      if( rc==SQLITE_OK ){
        rc = pager_truncate(pPager, nPage);
      }
    }
  }

  return rc;
}

/*

int sqlite3PagerClose(Pager *pPager){

  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  pPager->errCode = 0;
  pPager->exclusiveMode = 0;
  pager_reset(pPager);

  pagerUnlockAndRollback(pPager);

  enable_simulated_io_errors();
  sqlite3EndBenignMalloc();
  PAGERTRACE2("CLOSE %d\n", PAGERID(pPager));
  IOTRACE(("CLOSE %p\n", pPager))
  if( pPager->journalOpen ){
    sqlite3OsClose(pPager->jfd);
  }

static int syncJournal(Pager *pPager){
  int rc = SQLITE_OK;

  /* Sync the journal before modifying the main database
  ** (assuming there is a journal and it needs to be synced.)
  */
  if( pPager->needSync ){
    if( !pPager->tempFile ){

      int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
      assert( pPager->journalOpen );

      if( 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
        /* 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

  }

  assert( pPg->flags&PGHDR_DIRTY );
  if( pPager->errCode==SQLITE_OK ){
    if( pPg->flags&PGHDR_NEED_SYNC ){
      rc = syncJournal(pPager);
      if( rc==SQLITE_OK && pPager->fullSync && 

        !(sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND)
      ){
        pPager->nRec = 0;
        rc = writeJournalHdr(pPager);
      }
    }
    if( rc==SQLITE_OK ){

  */
  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
    return pPager->errCode;
  }

  if( pPager->state==PAGER_UNLOCK || isErrorReset ){
    sqlite3_vfs *pVfs = pPager->pVfs;
    if( !MEMDB ){
      int isHotJournal;
      assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
      if( !pPager->noReadlock ){
        rc = pager_wait_on_lock(pPager, SHARED_LOCK);
        if( rc!=SQLITE_OK ){
          assert( pPager->state==PAGER_UNLOCK );
          return pager_error(pPager, rc);
        }
        assert( pPager->state>=SHARED_LOCK );
      }
  
      /* If a journal file exists, and there is no RESERVED lock on the
      ** database file, then it either needs to be played back or deleted.
      */
      if( !isErrorReset ){
        rc = hasHotJournal(pPager, &isHotJournal);
        if( rc!=SQLITE_OK ){
          goto failed;
        }
      }
      if( isErrorReset || isHotJournal ){
        /* Get an EXCLUSIVE lock on the database file. At this point it is
        ** important that a RESERVED lock is not obtained on the way to the
        ** EXCLUSIVE lock. If it were, another process might open the
        ** database file, detect the RESERVED lock, and conclude that the
        ** 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 its own EXCLUSIVE lock on the database file.
        */
        if( pPager->state<EXCLUSIVE_LOCK ){
          rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
          if( rc!=SQLITE_OK ){
            rc = pager_error(pPager, rc);
            goto failed;
          }
          pPager->state = PAGER_EXCLUSIVE;
        }
 
        /* Open the journal for read/write access. This is because in 
        ** exclusive-access mode the file descriptor will be kept open and
        ** possibly used for a transaction later on. On some systems, the
        ** OsTruncate() call used in exclusive-access mode also requires
        ** a read/write file handle.
        */
        if( !isErrorReset && pPager->journalOpen==0 ){
          int res;
          rc = sqlite3OsAccess(pVfs,pPager->zJournal,SQLITE_ACCESS_EXISTS,&res);
          if( rc==SQLITE_OK ){
            if( res ){
              int fout = 0;
              int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
              assert( !pPager->tempFile );
              rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
              assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
              if( fout&SQLITE_OPEN_READONLY ){
                rc = SQLITE_BUSY;
                sqlite3OsClose(pPager->jfd);
              }
            }else{
              /* If the journal does not exist, that means some other process
              ** has already rolled it back */
              rc = SQLITE_BUSY;
            }
          }
        }
        if( rc!=SQLITE_OK ){
          if( rc!=SQLITE_NOMEM && rc!=SQLITE_IOERR_UNLOCK 
           && rc!=SQLITE_IOERR_NOMEM 
          ){
            rc = SQLITE_BUSY;
          }
          goto failed;
        }
        pPager->journalOpen = 1;
        pPager->journalStarted = 0;
        pPager->journalOff = 0;
        pPager->setMaster = 0;
        pPager->journalHdr = 0;
 
        /* Playback and delete the journal.  Drop the database write
        ** lock and reacquire the read lock.
        */
        rc = pager_playback(pPager, 1);
        if( rc!=SQLITE_OK ){
          rc = pager_error(pPager, rc);
          goto failed;
        }
        assert(pPager->state==PAGER_SHARED || 
            (pPager->exclusiveMode && pPager->state>PAGER_SHARED)
        );
      }

      if( sqlite3PcachePagecount(pPager->pPCache)>0 ){
        /* The shared-lock has just been acquired on the database file
        ** and there are already pages in the cache (from a previous
        ** read or write transaction).  Check to see if the database
        ** has been modified.  If the database has changed, flush the
        ** cache.
        **
        ** Database changes is detected by looking at 15 bytes beginning
        ** at offset 24 into the file.  The first 4 of these 16 bytes are
        ** a 32-bit counter that is incremented with each change.  The
        ** other bytes change randomly with each file change when
        ** a codec is in use.
        ** 
        ** There is a vanishingly small chance that a change will not be 
        ** detected.  The chance of an undetected change is so small that
        ** it can be neglected.
        */
        char dbFileVers[sizeof(pPager->dbFileVers)];
        sqlite3PagerPagecount(pPager, 0);

        if( pPager->errCode ){
          rc = pPager->errCode;
          goto failed;
        }

        if( pPager->dbSize>0 ){
          IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
          rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
          if( rc!=SQLITE_OK ){
            goto failed;
          }
        }else{
          memset(dbFileVers, 0, sizeof(dbFileVers));
        }

        if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
          pager_reset(pPager);
        }
      }
    }
    assert( pPager->exclusiveMode || pPager->state<=PAGER_SHARED );
    if( pPager->state==PAGER_UNLOCK ){
      pPager->state = PAGER_SHARED;
    }
  }

  int noContent       /* Do not bother reading content from disk if true */
){
  PgHdr *pPg = 0;
  int rc;

  assert( pPager->state==PAGER_UNLOCK 
       || sqlite3PcacheRefCount(pPager->pPCache)>0 
       || pgno==1 
  );

  /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
  ** number greater than this, or zero, is requested.
  */
  if( pgno>PAGER_MAX_PGNO || pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
    return SQLITE_CORRUPT_BKPT;

    /* The pager cache has created a new page. Its content needs to 
    ** be initialized.
    */
    int nMax;
    PAGER_INCR(pPager->nMiss);
    pPg->pPager = pPager;
    if( sqlite3BitvecTest(pPager->pInJournal, pgno) ){
      assert( !MEMDB );
      pPg->flags |= PGHDR_IN_JOURNAL;
    }
    memset(pPg->pExtra, 0, pPager->nExtra);

    rc = sqlite3PagerPagecount(pPager, &nMax);
    if( rc!=SQLITE_OK ){
      sqlite3PagerUnref(pPg);

** write lock if anything goes wrong.
*/
static int pager_open_journal(Pager *pPager){
  sqlite3_vfs *pVfs = pPager->pVfs;
  int flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_CREATE);

  int rc;
  assert( !MEMDB );
  assert( pPager->state>=PAGER_RESERVED );
  assert( pPager->useJournal );
  assert( pPager->pInJournal==0 );
  sqlite3PagerPagecount(pPager, 0);
  pPager->pInJournal = sqlite3BitvecCreate(pPager->dbSize);
  if( pPager->pInJournal==0 ){
    rc = SQLITE_NOMEM;
    goto failed_to_open_journal;
  }

  if( pPager->journalOpen==0 ){
    if( pPager->tempFile ){
      flags |= (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL);
    }else{
      flags |= (SQLITE_OPEN_MAIN_JOURNAL);
    }




#ifdef SQLITE_ENABLE_ATOMIC_WRITE
    rc = sqlite3JournalOpen(
        pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
    );
#else
    rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
#endif

    assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
    pPager->journalOff = 0;
    pPager->setMaster = 0;
    pPager->journalHdr = 0;
    if( rc!=SQLITE_OK ){
      if( rc==SQLITE_NOMEM ){
        sqlite3OsDelete(pVfs, pPager->zJournal, 0);

int sqlite3PagerBegin(DbPage *pPg, int exFlag){
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;
  assert( pPg->nRef>0 );
  assert( pPager->state!=PAGER_UNLOCK );
  if( pPager->state==PAGER_SHARED ){
    assert( pPager->pInJournal==0 );

    sqlite3PcacheAssertFlags(pPager->pPCache, 0, PGHDR_IN_JOURNAL);
    if( MEMDB ){
      pPager->state = PAGER_EXCLUSIVE;
      pPager->origDbSize = pPager->dbSize;
    }else{
      rc = sqlite3OsLock(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 ){
        return rc;
      }
      pPager->dirtyCache = 0;
      PAGERTRACE2("TRANSACTION %d\n", PAGERID(pPager));
      if( pPager->useJournal && !pPager->tempFile
             && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
        rc = pager_open_journal(pPager);
      }
    }
  }else if( pPager->journalOpen && pPager->journalOff==0 ){
    /* This happens when the pager was in exclusive-access mode the last
    ** time a (read or write) transaction was successfully concluded
    ** by this connection. Instead of deleting the journal file it was 
    ** kept open and either was truncated to 0 bytes or its header was
    ** overwritten with zeros.

    pPager->dirtyCache = 1;
    pPager->dbModified = 1;
  
    /* The transaction journal now exists and we have a RESERVED or an
    ** EXCLUSIVE lock on the main database file.  Write the current page to
    ** the transaction journal if it is not there already.
    */
    if( !(pPg->flags&PGHDR_IN_JOURNAL) && (pPager->journalOpen || MEMDB) ){
      if( (int)pPg->pgno <= pPager->origDbSize ){
        if( MEMDB ){
          PAGERTRACE3("JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
          rc = sqlite3PcachePreserve(pPg, 0);
          if( rc!=SQLITE_OK ){
            return rc;
          }
        }else{
          u32 cksum;
          char *pData2;

          /* We should never write to the journal file the page that
          ** contains the database locks.  The following assert verifies
          ** that we do not. */
          assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
          pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
          cksum = pager_cksum(pPager, (u8*)pData2);
          rc = write32bits(pPager->jfd, pPager->journalOff, pPg->pgno);
          if( rc==SQLITE_OK ){
            rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize,
                                pPager->journalOff + 4);
            pPager->journalOff += pPager->pageSize+4;
          }
          if( rc==SQLITE_OK ){
            rc = write32bits(pPager->jfd, pPager->journalOff, cksum);
            pPager->journalOff += 4;
          }
          IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno, 
                   pPager->journalOff, pPager->pageSize));
          PAGER_INCR(sqlite3_pager_writej_count);
          PAGERTRACE5("JOURNAL %d page %d needSync=%d hash(%08x)\n",
               PAGERID(pPager), pPg->pgno, 
               ((pPg->flags&PGHDR_NEED_SYNC)?1:0), pager_pagehash(pPg));

          /* An error has occured writing to the journal file. The 
          ** transaction will be rolled back by the layer above.
          */
          if( rc!=SQLITE_OK ){
            return rc;
          }

          pPager->nRec++;
          assert( pPager->pInJournal!=0 );
          sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
          if( !pPager->noSync ){
            pPg->flags |= PGHDR_NEED_SYNC;
          }
          if( pPager->stmtInUse ){
            sqlite3BitvecSet(pPager->pInStmt, pPg->pgno);
          }
        }
      }else{
        if( !pPager->journalStarted && !pPager->noSync ){
          pPg->flags |= PGHDR_NEED_SYNC;
        }
        PAGERTRACE4("APPEND %d page %d needSync=%d\n",
                PAGERID(pPager), pPg->pgno,

    */
    if( pPager->stmtInUse 
     && !pageInStatement(pPg) 
     && (int)pPg->pgno<=pPager->stmtSize 
    ){
      assert( (pPg->flags&PGHDR_IN_JOURNAL) 
                 || (int)pPg->pgno>pPager->origDbSize );
      if( MEMDB ){
        rc = sqlite3PcachePreserve(pPg, 1);
        if( rc!=SQLITE_OK ){
          return rc;
        }
        PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
      }else{
        i64 offset = pPager->stmtNRec*(4+pPager->pageSize);
        char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
        rc = write32bits(pPager->stfd, offset, pPg->pgno);
        if( rc==SQLITE_OK ){
          rc = sqlite3OsWrite(pPager->stfd, pData2, pPager->pageSize, offset+4);
        }
        PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
        if( rc!=SQLITE_OK ){
          return rc;
        }
        pPager->stmtNRec++;
        assert( pPager->pInStmt!=0 );
        sqlite3BitvecSet(pPager->pInStmt, pPg->pgno);
      }
    }
  }

  /* Update the database size and return.
  */
  assert( pPager->state>=PAGER_SHARED );
  if( pPager->dbSize<(int)pPg->pgno ){
    pPager->dbSize = pPg->pgno;
    if( !MEMDB && pPager->dbSize==PENDING_BYTE/pPager->pageSize ){
      pPager->dbSize++;
    }
  }
  return rc;
}

/*

int sqlite3PagerWrite(DbPage *pDbPage){
  int rc = SQLITE_OK;

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

  if( !MEMDB && nPagePerSector>1 ){
    Pgno nPageCount;          /* Total number of pages in database file */
    Pgno pg1;                 /* First page of the sector pPg is located on. */
    int nPage;                /* Number of pages starting at pg1 to journal */
    int ii;
    int needSync = 0;

    /* Set the doNotSync flag to 1. This is because we cannot allow a journal
    ** header to be written between the pages journaled by this function.
    */

    assert( pPager->doNotSync==0 );
    pPager->doNotSync = 1;

    /* This trick assumes that both the page-size and sector-size are
    ** an integer power of 2. It sets variable pg1 to the identifier
    ** of the first page of the sector pPg is located on.
    */

** rolled back in spite of the sqlite3PagerDontRollback() call.
*/
int sqlite3PagerDontWrite(DbPage *pDbPage){
  PgHdr *pPg = pDbPage;
  Pager *pPager = pPg->pPager;
  int rc;

  if( MEMDB || pPg->pgno>pPager->origDbSize ){
    return SQLITE_OK;
  }
  if( pPager->pAlwaysRollback==0 ){
    assert( pPager->pInJournal );
    pPager->pAlwaysRollback = sqlite3BitvecCreate(pPager->origDbSize);
    if( !pPager->pAlwaysRollback ){
      return SQLITE_NOMEM;

  */
  if( pPager->journalOpen==0 
   || sqlite3BitvecTest(pPager->pAlwaysRollback, pPg->pgno)
   || pPg->pgno>pPager->origDbSize
  ){
    return;
  }
  assert( !MEMDB );    /* For a memdb, pPager->journalOpen is always 0 */

#ifdef SQLITE_SECURE_DELETE
  if( (pPg->flags & PGHDR_IN_JOURNAL)!=0 || (int)pPg->pgno>pPager->origDbSize ){
    return;
  }
#endif

  if( pPager->dbModified==0 &&
        (pPager->journalMode!=PAGER_JOURNALMODE_DELETE ||
          pPager->exclusiveMode!=0) ){
    assert( pPager->dirtyCache==0 || pPager->journalOpen==0 );
    return SQLITE_OK;
  }
  PAGERTRACE2("COMMIT %d\n", PAGERID(pPager));
  if( MEMDB ){
    sqlite3PcacheCommit(pPager->pPCache, 0);
    sqlite3PcacheCleanAll(pPager->pPCache);
    sqlite3PcacheAssertFlags(pPager->pPCache, 0, PGHDR_IN_JOURNAL);
    pPager->state = PAGER_SHARED;
  }else{
    assert( pPager->state==PAGER_SYNCED || !pPager->dirtyCache );
    rc = pager_end_transaction(pPager, pPager->setMaster);
    rc = pager_error(pPager, rc);
  }
  return rc;
}

/*
** Rollback all changes.  The database falls back to PAGER_SHARED mode.
** All in-memory cache pages revert to their original data contents.
** The journal is deleted.
**
** This routine cannot fail unless some other process is not following
** the correct locking protocol or unless some other
** process is writing trash into the journal file (SQLITE_CORRUPT) or
** unless a prior malloc() failed (SQLITE_NOMEM).  Appropriate error
** codes are returned for all these occasions.  Otherwise,
** SQLITE_OK is returned.
*/
int sqlite3PagerRollback(Pager *pPager){
  int rc = SQLITE_OK;
  PAGERTRACE2("ROLLBACK %d\n", PAGERID(pPager));
  if( MEMDB ){
    sqlite3PcacheRollback(pPager->pPCache, 1, pPager->xReiniter);
    sqlite3PcacheRollback(pPager->pPCache, 0, pPager->xReiniter);
    sqlite3PcacheCleanAll(pPager->pPCache);
    sqlite3PcacheAssertFlags(pPager->pPCache, 0, PGHDR_IN_JOURNAL);
    pPager->dbSize = pPager->origDbSize;
    pager_truncate_cache(pPager);
    pPager->stmtInUse = 0;
    pPager->state = PAGER_SHARED;
  }else if( !pPager->dirtyCache || !pPager->journalOpen ){
    rc = pager_end_transaction(pPager, pPager->setMaster);
  }else if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
    if( pPager->state>=PAGER_EXCLUSIVE ){
      pager_playback(pPager, 0);
    }
    rc = pPager->errCode;
  }else{
    if( pPager->state==PAGER_RESERVED ){
      int rc2;
      rc = pager_playback(pPager, 0);
      rc2 = pager_end_transaction(pPager, pPager->setMaster);
      if( rc==SQLITE_OK ){
        rc = rc2;
      }
    }else{
      rc = pager_playback(pPager, 0);
    }


    pPager->dbSize = -1;


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

*/
static int pagerStmtBegin(Pager *pPager){
  int rc;
  assert( !pPager->stmtInUse );
  assert( pPager->state>=PAGER_SHARED );
  assert( pPager->dbSize>=0 );
  PAGERTRACE2("STMT-BEGIN %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPager->stmtInUse = 1;
    pPager->stmtSize = pPager->dbSize;
    return SQLITE_OK;
  }
  if( !pPager->journalOpen ){
    pPager->stmtAutoopen = 1;
    return SQLITE_OK;
  }
  assert( pPager->journalOpen );
  assert( pPager->pInStmt==0 );
  pPager->pInStmt = sqlite3BitvecCreate(pPager->dbSize);
  if( pPager->pInStmt==0 ){
    /* sqlite3OsLock(pPager->fd, SHARED_LOCK); */
    return SQLITE_NOMEM;
  }
  pPager->stmtJSize = pPager->journalOff;
  pPager->stmtSize = pPager->dbSize;
  pPager->stmtHdrOff = 0;
  pPager->stmtCksum = pPager->cksumInit;
  if( !pPager->stmtOpen ){



    rc = sqlite3PagerOpentemp(pPager, pPager->stfd, SQLITE_OPEN_SUBJOURNAL);
    if( rc ){
      goto stmt_begin_failed;

    }
    pPager->stmtOpen = 1;
    pPager->stmtNRec = 0;
  }
  pPager->stmtInUse = 1;
  return SQLITE_OK;
 

/*
** Commit a statement.
*/
int sqlite3PagerStmtCommit(Pager *pPager){
  if( pPager->stmtInUse ){
    PAGERTRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
    if( !MEMDB ){
      sqlite3BitvecDestroy(pPager->pInStmt);
      pPager->pInStmt = 0;
    }else{
      sqlite3PcacheCommit(pPager->pPCache, 1);
    }
    pPager->stmtNRec = 0;
    pPager->stmtInUse = 0;



  }
  pPager->stmtAutoopen = 0;
  return SQLITE_OK;
}

/*
** Rollback a statement.
*/
int sqlite3PagerStmtRollback(Pager *pPager){
  int rc;
  if( pPager->stmtInUse ){
    PAGERTRACE2("STMT-ROLLBACK %d\n", PAGERID(pPager));
    if( MEMDB ){
      sqlite3PcacheRollback(pPager->pPCache, 1, pPager->xReiniter);
      pPager->dbSize = pPager->stmtSize;
      pager_truncate_cache(pPager);
      rc = SQLITE_OK;
    }else{
      rc = pager_stmt_playback(pPager);
    }
    sqlite3PagerStmtCommit(pPager);
  }else{
    rc = SQLITE_OK;
  }
  pPager->stmtAutoopen = 0;
  return rc;
}

  pPg->flags &= ~(PGHDR_NEED_SYNC|PGHDR_IN_JOURNAL);
  pPgOld = pager_lookup(pPager, pgno);
  assert( !pPgOld || pPgOld->nRef==1 );
  if( pPgOld ){
    pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
  }
  if( sqlite3BitvecTest(pPager->pInJournal, pgno) ){
    assert( !MEMDB );
    pPg->flags |= PGHDR_IN_JOURNAL;
  }

  sqlite3PcacheMove(pPg, pgno);
  if( pPgOld ){
    sqlite3PcacheMove(pPgOld, 0);
    sqlite3PcacheRelease(pPgOld);

** If the parameter is not _QUERY, then the journal-mode is set to the
** value specified.
**
** The returned indicate the current (possibly updated)
** journal-mode.
*/
int sqlite3PagerJournalMode(Pager *pPager, int eMode){

  assert( eMode==PAGER_JOURNALMODE_QUERY
            || eMode==PAGER_JOURNALMODE_DELETE
            || eMode==PAGER_JOURNALMODE_TRUNCATE
            || eMode==PAGER_JOURNALMODE_PERSIST
            || eMode==PAGER_JOURNALMODE_OFF );

  assert( PAGER_JOURNALMODE_QUERY<0 );
  if( eMode>=0 ){
    pPager->journalMode = eMode;
  }else{
    assert( eMode==PAGER_JOURNALMODE_QUERY );

  }
  return (int)pPager->journalMode;
}

/*
** Get/set the size-limit used for persistent journal files.
*/

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem.  The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.85 2008/09/29 11:49:48 danielk1977 Exp $
*/

#ifndef _PAGER_H_
#define _PAGER_H_

/*
** If defined as non-zero, auto-vacuum is enabled by default. Otherwise

** Valid values for the second argument to sqlite3PagerJournalMode().
*/
#define PAGER_JOURNALMODE_QUERY      -1
#define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */
#define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */
#define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */
#define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */


/*
** See source code comments for a detailed description of the following
** routines:
*/
int sqlite3PagerOpen(sqlite3_vfs *, Pager **ppPager, const char*, int,int,int);
void sqlite3PagerSetBusyhandler(Pager*, BusyHandler *pBusyHandler);

/*
** 2008 August 05
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file implements that page cache.
**
** @(#) $Id: pcache.c,v 1.33 2008/09/29 11:49:48 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** A complete page cache is an instance of this structure.
**
** A cache may only be deleted by its owner and while holding the

** Deallocate a page
*/
static void pcachePageFree(PgHdr *p){
  assert( sqlite3_mutex_held(pcache_g.mutex) );
  if( p->pCache->bPurgeable ){
    pcache_g.nCurrentPage--;
  }
  pcacheFree(p->apSave[0]);
  pcacheFree(p->apSave[1]);
  pcacheFree(p);
}

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/*
** Return the number of bytes that will be returned to the heap when
** the argument is passed to pcachePageFree().

  pcacheAddToList(&pCache->pDirty, p);
  pcacheExitMutex();
  p->flags |= PGHDR_DIRTY;
}

static void pcacheMakeClean(PgHdr *p){
  PCache *pCache = p->pCache;
  assert( p->apSave[0]==0 && p->apSave[1]==0 );
  assert( p->flags & PGHDR_DIRTY );
  pcacheRemoveFromList(&pCache->pDirty, p);
  pcacheAddToList(&pCache->pClean, p);
  p->flags &= ~PGHDR_DIRTY;
  if( p->nRef==0 ){
    pcacheAddToLruList(p);
    pCache->nPinned--;

/*
** Make every page in the cache clean.
*/
void sqlite3PcacheCleanAll(PCache *pCache){
  PgHdr *p;
  pcacheEnterMutex();
  while( (p = pCache->pDirty)!=0 ){
    assert( p->apSave[0]==0 && p->apSave[1]==0 );
    pcacheRemoveFromList(&pCache->pDirty, p);
    p->flags &= ~PGHDR_DIRTY;
    pcacheAddToList(&pCache->pClean, p);
    if( p->nRef==0 ){
      pcacheAddToLruList(p);
      pCache->nPinned--;
    }

*/
void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
  assert( p->nRef>0 );
  pcacheEnterMutex();
  pcacheRemoveFromHash(p);
  p->pgno = newPgno;
  if( newPgno==0 ){
    pcacheFree(p->apSave[0]);
    pcacheFree(p->apSave[1]);
    p->apSave[0] = 0;
    p->apSave[1] = 0;
    if( (p->flags & PGHDR_DIRTY) ){
      pcacheMakeClean(p);
    }
    p->flags = PGHDR_REUSE_UNLIKELY;
  }
  pcacheAddToHash(p);
  pcacheExitMutex();

    pcache_g.nMinPage -= pCache->nMin;
    pcacheEnforceMaxPage();
  }
  sqlite3_free(pCache->apHash);
  pcacheExitMutex();
}

/*
** Preserve the content of the page.  It is assumed that the content
** has not been preserved already.
**
** If idJournal==0 then this is for the overall transaction.
** If idJournal==1 then this is for the statement journal.
**
** This routine is used for in-memory databases only.
**
** Return SQLITE_OK or SQLITE_NOMEM if a memory allocation fails.
*/
int sqlite3PcachePreserve(PgHdr *p, int idJournal){
  void *x;
  int sz;
  assert( p->pCache->bPurgeable==0 );
  assert( p->apSave[idJournal]==0 );
  sz = p->pCache->szPage;
  p->apSave[idJournal] = x = sqlite3PageMalloc( sz );
  if( x==0 ) return SQLITE_NOMEM;
  memcpy(x, p->pData, sz);
  return SQLITE_OK;
}

/*
** Commit a change previously preserved.
*/
void sqlite3PcacheCommit(PCache *pCache, int idJournal){
  PgHdr *p;
  int mask = idJournal==0 ? ~PGHDR_IN_JOURNAL : 0xffffff;
  pcacheEnterMutex();     /* Mutex is required to call pcacheFree() */
  for(p=pCache->pDirty; p; p=p->pNext){
    if( p->apSave[idJournal] ){
      pcacheFree(p->apSave[idJournal]);
      p->apSave[idJournal] = 0;
    }
    p->flags &= mask;
  }
  pcacheExitMutex();
}

/*
** Rollback a change previously preserved.
*/
void sqlite3PcacheRollback(
  PCache *pCache,                  /* Pager cache */
  int idJournal,                   /* Which copy to rollback to */
  void (*xReiniter)(PgHdr*)        /* Called on each rolled back page */
){
  PgHdr *p;
  int sz;
  int mask = idJournal==0 ? ~PGHDR_IN_JOURNAL : 0xffffff;
  pcacheEnterMutex();     /* Mutex is required to call pcacheFree() */
  sz = pCache->szPage;
  for(p=pCache->pDirty; p; p=p->pNext){
    if( p->apSave[idJournal] ){
      memcpy(p->pData, p->apSave[idJournal], sz);
      pcacheFree(p->apSave[idJournal]);
      p->apSave[idJournal] = 0;
      if( xReiniter ){
        xReiniter(p);
      }
    }
    p->flags &= mask;
  }
  pcacheExitMutex();
}

#ifndef NDEBUG
/* 
** Assert flags settings on all pages.  Debugging only.
*/
void sqlite3PcacheAssertFlags(PCache *pCache, int trueMask, int falseMask){
  PgHdr *p;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem. 
**
** @(#) $Id: pcache.h,v 1.13 2008/10/11 17:42:29 drh Exp $
*/

#ifndef _PCACHE_H_

typedef struct PgHdr PgHdr;
typedef struct PCache PCache;

  u16 flags;                     /* PGHDR flags defined below */
  /**********************************************************************
  ** Elements above are public.  All that follows is private to pcache.c
  ** and should not be accessed by other modules.
  */
  i16 nRef;                      /* Number of users of this page */
  PCache *pCache;                /* Cache that owns this page */
  void *apSave[2];               /* Journal entries for in-memory databases */
  /**********************************************************************
  ** Elements above are accessible at any time by the owner of the cache
  ** without the need for a mutex.  The elements that follow can only be
  ** accessed while holding the SQLITE_MUTEX_STATIC_LRU mutex.
  */
  PgHdr *pNextHash, *pPrevHash;  /* Hash collision chain for PgHdr.pgno */
  PgHdr *pNext, *pPrev;          /* List of clean or dirty pages */

/* Change a page number.  Used by incr-vacuum. */
void sqlite3PcacheMove(PgHdr*, Pgno);

/* Remove all pages with pgno>x.  Reset the cache if x==0 */
void sqlite3PcacheTruncate(PCache*, Pgno x);

/* Routines used to implement transactions on memory-only databases. */
int sqlite3PcachePreserve(PgHdr*, int);    /* Preserve current page content */
void sqlite3PcacheCommit(PCache*, int);    /* Drop preserved copy */
void sqlite3PcacheRollback(PCache*, int, void (*xReiniter)(PgHdr*));

/* Get a list of all dirty pages in the cache, sorted by page number */
PgHdr *sqlite3PcacheDirtyList(PCache*);

/* Reset and close the cache object */
void sqlite3PcacheClose(PCache*);

/* Clear flags from pages of the page cache */

/*
** 2003 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the PRAGMA command.
**
** $Id: pragma.c,v 1.189 2008/10/10 17:47:21 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/* Ignore this whole file if pragmas are disabled
*/
#if !defined(SQLITE_OMIT_PRAGMA) && !defined(SQLITE_OMIT_PARSER)

    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "locking_mode", P4_STATIC);
    sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, zRet, 0);
    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
  }else

  /*
  **  PRAGMA [database.]journal_mode
  **  PRAGMA [database.]journal_mode = (delete|persist|off)
  */
  if( sqlite3StrICmp(zLeft,"journal_mode")==0 ){
    int eMode;
    static char * const azModeName[] = {"delete", "persist", "off", "truncate"};



    if( zRight==0 ){
      eMode = PAGER_JOURNALMODE_QUERY;
    }else{
      int n = strlen(zRight);
      eMode = sizeof(azModeName)/sizeof(azModeName[0]) - 1;
      while( eMode>=0 && sqlite3StrNICmp(zRight, azModeName[eMode], n)!=0 ){

      }
      pPager = sqlite3BtreePager(pDb->pBt);
      eMode = sqlite3PagerJournalMode(pPager, eMode);
    }
    assert( eMode==PAGER_JOURNALMODE_DELETE
              || eMode==PAGER_JOURNALMODE_TRUNCATE
              || eMode==PAGER_JOURNALMODE_PERSIST
              || eMode==PAGER_JOURNALMODE_OFF );

    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "journal_mode", P4_STATIC);
    sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, 
           azModeName[eMode], P4_STATIC);
    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
  }else

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.784 2008/10/13 15:35:09 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build

#ifdef SQLITE_ENABLE_ATOMIC_WRITE
  int sqlite3JournalOpen(sqlite3_vfs *, const char *, sqlite3_file *, int, int);
  int sqlite3JournalSize(sqlite3_vfs *);
  int sqlite3JournalCreate(sqlite3_file *);
#else
  #define sqlite3JournalSize(pVfs) ((pVfs)->szOsFile)
#endif





#if SQLITE_MAX_EXPR_DEPTH>0
  void sqlite3ExprSetHeight(Parse *pParse, Expr *p);
  int sqlite3SelectExprHeight(Select *);
  int sqlite3ExprCheckHeight(Parse*, int);
#else
  #define sqlite3ExprSetHeight(x,y)

# 2008 April 17
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library. The focus
# of these tests is the journal mode pragma.
#
# $Id: jrnlmode.test,v 1.6 2008/09/26 21:08:08 drh Exp $

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

ifcapable {!pager_pragmas} {
  finish_test
  return

      PRAGMA journal_mode = PERSIST;
      ATTACH ':memory:' as aux1;
    }
    execsql {
      PRAGMA main.journal_mode;
      PRAGMA aux1.journal_mode;
    }
  } {persist persist}
  do_test jrnlmode-1.10 {
    execsql {
      PRAGMA main.journal_mode = OFF;
    }
    execsql {
      PRAGMA main.journal_mode;
      PRAGMA temp.journal_mode;
      PRAGMA aux1.journal_mode;
    }
  } {off persist persist}
  do_test jrnlmode-1.11 {
    execsql {
      PRAGMA journal_mode;
    }
  } {persist}
  do_test jrnlmode-1.12 {
    execsql {
      ATTACH ':memory:' as aux2;
    }
    execsql {
      PRAGMA main.journal_mode;
      PRAGMA aux1.journal_mode;
      PRAGMA aux2.journal_mode;
    }
  } {off persist persist}
  do_test jrnlmode-1.11 {

    execsql {
      PRAGMA aux1.journal_mode = DELETE;
    }
    execsql {
      PRAGMA main.journal_mode;
      PRAGMA aux1.journal_mode;
      PRAGMA aux2.journal_mode;
    }
  } {off delete persist}
  do_test jrnlmode-1.12 {
    execsql {
      PRAGMA journal_mode = delete;
    }
    execsql {
      PRAGMA main.journal_mode;
      PRAGMA temp.journal_mode;
      PRAGMA aux1.journal_mode;
      PRAGMA aux2.journal_mode;
    }
  } {delete delete delete delete}
  do_test jrnlmode-1.13 {
    execsql {
      ATTACH ':memory:' as aux3;
    }
    execsql {
      PRAGMA main.journal_mode;
      PRAGMA temp.journal_mode;
      PRAGMA aux1.journal_mode;
      PRAGMA aux2.journal_mode;
      PRAGMA aux3.journal_mode;
    }
  } {delete delete delete delete delete}
  do_test jrnlmode-1.14 {
    execsql {
      PRAGMA journal_mode = TRUNCATE;
    }
    execsql {
      PRAGMA main.journal_mode;
      PRAGMA temp.journal_mode;
      PRAGMA aux1.journal_mode;
      PRAGMA aux2.journal_mode;
      PRAGMA aux3.journal_mode;
    }
  } {truncate truncate truncate truncate truncate}
  
  do_test jrnlmode-1.99 {
    execsql {
      DETACH aux1;
      DETACH aux2;
      DETACH aux3;
    }

# 2001 September 15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is page cache subsystem.
#
# $Id: pager.test,v 1.31 2008/08/20 14:49:25 danielk1977 Exp $


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

if {[info commands pager_open]!=""} {
db close

# Test truncate on an in-memory database is Ok.
ifcapable memorydb {
  do_test pager-4.6.2 {
    set ::p2 [pager_open :memory: 10]
    pager_truncate $::p2 5
  } {}
  do_test pager-4.6.3 {

    for {set i 1} {$i<5} {incr i} {
      set p [page_get $::p2 $i]
      page_write $p "Page $i"
      pager_commit $::p2
      page_unref $p
    }

    # pager_truncate $::p2 3
  } {}
  do_test pager-4.6.4 {
    pager_close $::p2
  } {}
}

# 2001 September 15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is page cache subsystem.
#
# $Id: pager2.test,v 1.7 2008/08/20 14:49:25 danielk1977 Exp $


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

# Don't run this test file if the pager test interface [pager_open] is not
# available, or the library was compiled without in-memory database support.

do_test pager2-1.0 {
  set v [catch {
    set ::p1 [pager_open :memory: 10]
  } msg]
} {0}
do_test pager2-1.1 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size 0 state 0 err 0 hit 0 miss 0 ovfl 0}
do_test pager2-1.2 {
  pager_pagecount $::p1
} {0}
do_test pager2-1.3 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size 0 state 0 err 0 hit 0 miss 0 ovfl 0}
do_test pager2-1.4 {
  pager_close $::p1
} {}

# Try to write a few pages.
#
do_test pager2-2.1 {

#  lappend v $msg
#} {1 SQLITE_ERROR}
do_test pager2-2.3.1 {
  set ::gx [page_lookup $::p1 1]
} {}
do_test pager2-2.3.2 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size 0 state 0 err 0 hit 0 miss 0 ovfl 0}
do_test pager2-2.3.3 {
  set v [catch {
    set ::g1 [page_get $::p1 1]
  } msg]
  if {$v} {lappend v $msg}
  set v
} {0}
do_test pager2-2.3.3 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.3.4 {
  set ::gx [page_lookup $::p1 1]
  page_unref $::gx
  expr {$::gx!=""}
} {1}
do_test pager2-2.3.5 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.3.6 {
  expr {$::g1==$::gx}
} {1}
do_test pager2-2.3.7 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.4 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.5 {
  pager_pagecount $::p1
} {0}
do_test pager2-2.6 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.7 {
  page_number $::g1
} {1}
do_test pager2-2.8 {
  page_read $::g1
} {}
do_test pager2-2.9 {
  page_unref $::g1
} {}
do_test pager2-2.10 {
  pager_stats $::p1
} {ref 0 page 1 max 10 size 0 state 0 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.11 {
  set ::g1 [page_get $::p1 1]
  expr {$::g1!=0}
} {1}
do_test pager2-2.12 {
  page_number $::g1
} {1}
do_test pager2-2.13 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.14 {
  set v [catch {
    page_write $::g1 "Page-One"
  } msg]
  lappend v $msg
} {0 {}}
do_test pager2-2.15 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 1 state 4 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.16 {
  page_read $::g1
} {Page-One}
do_test pager2-2.17 {
  set v [catch {
    pager_commit $::p1
  } msg]
  lappend v $msg
} {0 {}}
do_test pager2-2.20 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 1 state 1 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.19 {
  pager_pagecount $::p1
} {1}
do_test pager2-2.21 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 1 state 1 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.22 {
  page_unref $::g1
} {}
do_test pager2-2.23 {
  pager_stats $::p1
} {ref 0 page 1 max 10 size 1 state 0 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.24 {
  set v [catch {
    page_get $::p1 1
  } ::g1]
  if {$v} {lappend v $::g1}
  set v
} {0}

    page_write $gx "Page-$i"
    page_unref $gx
  }
  pager_commit $::p1
  page_unref $::g(1)
} {}
for {set i 2} {$i<=20} {incr i} {

  do_test pager2-3.6.[expr {$i-1}] [subst {
    set gx \[page_get $::p1 $i\]
    set v \[page_read \$gx\]
    page_unref \$gx
    set v
  }] "Page-$i"

}
for {set i 1} {$i<=20} {incr i} {

  regsub -all CNT {
    set ::g1 [page_get $::p1 CNT]
    set ::g2 [page_get $::p1 CNT]
    set ::vx [page_read $::g2]
    expr {$::g1==$::g2}
  } $i body;
  do_test pager2-3.7.$i.1 $body {1}

    page_unref $::g1
    set gx [page_get $::p1 CNT]
    set vy [page_read $gx]
    page_unref $gx
    expr {$vy==$::vx}
  } $i body;
  do_test pager2-3.7.$i.3 $body {1}

}
do_test pager2-3.99 {
  pager_close $::p1
} {}

# tests of the checkpoint mechanism and api
#

  } "Page-$i v0"
}
do_test pager2-4.3 {
  lrange [pager_stats $::p1] 0 1
} {ref 1}
do_test pager2-4.4 {
  lrange [pager_stats $::p1] 8 9
} {state 1}

for {set i 1} {$i<20} {incr i} {
  do_test pager2-4.5.$i.0 {
    set res {}
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]

      }
    }
    set res
  } {}
  do_test pager2-4.5.$i.10 {
    pager_commit $p1
    lrange [pager_stats $p1] 8 9
  } {state 1}
}

do_test pager2-4.99 {
  page_unref $::g1
  pager_close $::p1
} {}

} ;# ifcapable inmemory
} ;# end if( has pager_open command );


finish_test

# 2008 June 21
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# $Id: permutations.test,v 1.35 2008/10/11 17:04:04 danielk1977 Exp $

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

# Argument processing.
#
#puts "PERM-DEBUG: argv=$argv"

# Run some ioerr-tests in autovacuum mode.
#
run_tests "autovacuum_ioerr" -description {
  Run ioerr.test in autovacuum mode.
} -presql {
  pragma auto_vacuum = 1
} -include ioerr.test



















ifcapable mem3 {
  run_tests "memsys3" -description {
    Run tests using the allocator in mem3.c.
  } -exclude {
    autovacuum.test           delete3.test              manydb.test
    bigrow.test               incrblob2.test            memdb.test

#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is verifying that a rollback in one statement
# caused by an ON CONFLICT ROLLBACK clause aborts any other pending
# statements.
#
# $Id: rollback.test,v 1.9 2008/10/13 14:16:11 drh Exp $

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

set DB [sqlite3_connection_pointer db]

do_test rollback-1.1 {

} {SQLITE_ROW}
do_test rollback-1.9 {
  sqlite3_finalize $STMT
} {SQLITE_OK}

set permutation ""
catch {set permutation $::permutations_test_prefix}
if {$tcl_platform(platform) == "unix" && $permutation ne "onefile"} {



  do_test rollback-2.1 {
    execsql {
      BEGIN;
      INSERT INTO t3 VALUES('hello world');
    }
    file copy -force test.db testA.db
    file copy -force test.db-journal testA.db-journal

   vdbefifo.c
   vdbemem.c
   vdbeaux.c
   vdbeapi.c
   vdbe.c
   vdbeblob.c
   journal.c


   walker.c
   resolve.c
   expr.c
   alter.c
   analyze.c
   attach.c