** 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 1.73 2003/02/11 14:55:41 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
    if( rc ) goto end_playback;
    rc = read32bits(format, &pPager->jfd, &pPager->cksumInit);
    if( rc ) goto end_playback;
    if( nRec==0xffffffff ){
      nRec = (szJ - JOURNAL_HDR_SZ(3))/JOURNAL_PG_SZ(3);
    }
  }else{
    nRec = (szJ - (sizeof(aMagic)+sizeof(Pgno))) / sizeof(PageRecord);

  }
  rc = read32bits(format, &pPager->jfd, &mxPg);
  if( rc!=SQLITE_OK ){
    goto end_playback;
  }

  rc = sqliteOsTruncate(&pPager->fd, SQLITE_PAGE_SIZE*(off_t)mxPg);
  if( rc!=SQLITE_OK ){
    goto end_playback;
  }
  pPager->dbSize = mxPg;
  
  /* Copy original pages out of the journal and back into the database file.
  */
  for(i=0; i<nRec; i++){
    rc = pager_playback_one_page(pPager, &pPager->jfd, format);
    if( rc!=SQLITE_OK ){
      if( rc==SQLITE_DONE ){
fprintf(stderr,"Playback complete after %d of %d records\n", i, nRec);
        rc = SQLITE_OK;
      }
      break;
    }
  }


................................................................................
  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 ){
      off_t szJ;
      assert( pPager->journalOpen );
      assert( !pPager->noSync );
#ifndef NDEBUG
      {
        off_t hdrSz, pgSz;
        hdrSz = JOURNAL_HDR_SZ(journal_format);
        pgSz = JOURNAL_PG_SZ(journal_format);
        rc = sqliteOsFileSize(&pPager->jfd, &pPager->syncJSize);
        if( rc!=0 ) return rc;
        assert( pPager->nRec*pgSz+hdrSz==pPager->syncJSize );
      }
#endif


      if( pPager->fullSync ){
        TRACE1("SYNC\n");
        rc = sqliteOsSync(&pPager->jfd);
        if( rc!=0 ) return rc;
      }
      sqliteOsSeek(&pPager->jfd, sizeof(aJournalMagic1));
      write32bits(&pPager->jfd, pPager->nRec);
      szJ = JOURNAL_HDR_SZ(journal_format) +
               pPager->nRec*JOURNAL_PG_SZ(journal_format);
      sqliteOsSeek(&pPager->jfd, szJ);

      TRACE1("SYNC\n");
      rc = sqliteOsSync(&pPager->jfd);
      if( rc!=0 ) return rc;
      pPager->journalStarted = 1;
    }
    pPager->needSync = 0;

** 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 1.74 2003/02/12 02:10:15 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
    if( rc ) goto end_playback;
    rc = read32bits(format, &pPager->jfd, &pPager->cksumInit);
    if( rc ) goto end_playback;
    if( nRec==0xffffffff ){
      nRec = (szJ - JOURNAL_HDR_SZ(3))/JOURNAL_PG_SZ(3);
    }
  }else{
    nRec = (szJ - JOURNAL_HDR_SZ(2))/JOURNAL_PG_SZ(2);
    assert( nRec*JOURNAL_PG_SZ(2)+JOURNAL_HDR_SZ(2)==szJ );
  }
  rc = read32bits(format, &pPager->jfd, &mxPg);
  if( rc!=SQLITE_OK ){
    goto end_playback;
  }
  assert( pPager->origDbSize==0 || pPager->origDbSize==mxPg );
  rc = sqliteOsTruncate(&pPager->fd, SQLITE_PAGE_SIZE*(off_t)mxPg);
  if( rc!=SQLITE_OK ){
    goto end_playback;
  }
  pPager->dbSize = mxPg;
  
  /* Copy original pages out of the journal and back into the database file.
  */
  for(i=0; i<nRec; i++){
    rc = pager_playback_one_page(pPager, &pPager->jfd, format);
    if( rc!=SQLITE_OK ){
      if( rc==SQLITE_DONE ){

        rc = SQLITE_OK;
      }
      break;
    }
  }


................................................................................
  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 ){

      assert( pPager->journalOpen );
      assert( !pPager->noSync );
#ifndef NDEBUG
      {
        off_t hdrSz, pgSz;
        hdrSz = JOURNAL_HDR_SZ(journal_format);
        pgSz = JOURNAL_PG_SZ(journal_format);
        rc = sqliteOsFileSize(&pPager->jfd, &pPager->syncJSize);
        if( rc!=0 ) return rc;
        assert( pPager->nRec*pgSz+hdrSz==pPager->syncJSize );
      }
#endif
      if( journal_format>=3 ){
        off_t szJ;
        if( pPager->fullSync ){
          TRACE1("SYNC\n");
          rc = sqliteOsSync(&pPager->jfd);
          if( rc!=0 ) return rc;
        }
        sqliteOsSeek(&pPager->jfd, sizeof(aJournalMagic1));
        write32bits(&pPager->jfd, pPager->nRec);
        szJ = JOURNAL_HDR_SZ(journal_format) +
                 pPager->nRec*JOURNAL_PG_SZ(journal_format);
        sqliteOsSeek(&pPager->jfd, szJ);
      }
      TRACE1("SYNC\n");
      rc = sqliteOsSync(&pPager->jfd);
      if( rc!=0 ) return rc;
      pPager->journalStarted = 1;
    }
    pPager->needSync = 0;