SQLite

******************************************************************************
**
** This file contains code for a VFS layer that acts as a wrapper around
** an existing VFS. The code in this file attempts to verify that SQLite
** correctly populates and syncs a journal file before writing to a
** corresponding database file.
**
** $Id: test_journal.c,v 1.17 2009/06/26 10:39:36 danielk1977 Exp $
*/
#if SQLITE_TEST          /* This file is used for testing only */

#include "sqlite3.h"
#include "sqliteInt.h"

/*

  sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PRNG));
}
static void leaveJtMutex(void){
  sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PRNG));
}

extern int sqlite3_io_error_pending;
extern int sqlite3_io_error_hit;
static void stop_ioerr_simulation(int *piSave, int *piSave2){
  *piSave = sqlite3_io_error_pending;
  *piSave2 = sqlite3_io_error_hit;
  sqlite3_io_error_pending = -1;
  sqlite3_io_error_hit = 0;
}
static void start_ioerr_simulation(int iSave, int iSave2){
  sqlite3_io_error_pending = iSave;
  sqlite3_io_error_hit = iSave2;
}

/*
** The jt_file pointed to by the argument may or may not be a file-handle
** open on a main database file. If it is, and a transaction is currently
** opened on the file, then discard all transaction related data.
*/

  pJournal->iMaxOff = 0;

  if( !pMain->pWritable || !pMain->aCksum || !aData ){
    rc = SQLITE_IOERR_NOMEM;
  }else if( pMain->nPage>0 ){
    u32 iTrunk;
    int iSave;
    int iSave2;

    stop_ioerr_simulation(&iSave, &iSave2);

    /* Read the database free-list. Add the page-number for each free-list
    ** leaf to the jt_file.pWritable bitvec.
    */
    rc = sqlite3OsRead(p, aData, pMain->nPagesize, 0);
    iTrunk = decodeUint32(&aData[32]);
    while( rc==SQLITE_OK && iTrunk>0 ){

        i64 iOff = (i64)(pMain->nPagesize) * (i64)ii;
        if( iOff==PENDING_BYTE ) continue;
        rc = sqlite3OsRead(pMain->pReal, aData, pMain->nPagesize, iOff);
        pMain->aCksum[ii] = genCksum(aData, pMain->nPagesize);
      }
    }

    start_ioerr_simulation(iSave, iSave2);
  }

  sqlite3_free(aData);
  return rc;
}















































































/*
** The first argument to this function is a handle open on a journal file.
** This function reads the journal file and adds the page number for each
** page in the journal to the Bitvec object passed as the second argument.
*/
static int readJournalFile(jt_file *p, jt_file *pMain){
  int rc = SQLITE_OK;
  unsigned char zBuf[28];
  sqlite3_file *pReal = p->pReal;
  sqlite3_int64 iOff = 0;
  sqlite3_int64 iSize = p->iMaxOff;
  unsigned char *aPage;
  int iSave;
  int iSave2;

  aPage = sqlite3_malloc(pMain->nPagesize);
  if( !aPage ){
    return SQLITE_IOERR_NOMEM;
  }

  stop_ioerr_simulation(&iSave, &iSave2);

  while( rc==SQLITE_OK && iOff<iSize ){
    u32 nRec, nPage, nSector, nPagesize;
    u32 ii;

    /* Read and decode the next journal-header from the journal file. */
    rc = sqlite3OsRead(pReal, zBuf, 28, iOff);

      }
    }

    iOff = ((iOff + (nSector-1)) / nSector) * nSector;
  }

finish_rjf:
  start_ioerr_simulation(iSave, iSave2);
  sqlite3_free(aPage);
  if( rc==SQLITE_IOERR_SHORT_READ ){
    rc = SQLITE_OK;
  }
  return rc;
}


/*
** Write data to an jt-file.
*/
static int jtWrite(
  sqlite3_file *pFile, 
  const void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  int rc;
  jt_file *p = (jt_file *)pFile;
  if( p->flags&SQLITE_OPEN_MAIN_JOURNAL ){
    if( iOfst==0 ){
      jt_file *pMain = locateDatabaseHandle(p->zName);
      assert( pMain );
  
      if( iAmt==28 ){
        /* Zeroing the first journal-file header. This is the end of a
        ** transaction. */
        closeTransaction(pMain);
      }else if( iAmt!=12 ){
        /* Writing the first journal header to a journal file. This happens
        ** when a transaction is first started.  */
        u8 *z = (u8 *)zBuf;
        pMain->nPage = decodeUint32(&z[16]);
        pMain->nPagesize = decodeUint32(&z[24]);
        if( SQLITE_OK!=(rc=openTransaction(pMain, p)) ){
          return rc;
        }
      }
    }
    if( p->iMaxOff<(iOfst + iAmt) ){
      p->iMaxOff = iOfst + iAmt;
    }
  }

  if( p->flags&SQLITE_OPEN_MAIN_DB && p->pWritable ){
    if( iAmt<p->nPagesize 
     && p->nPagesize%iAmt==0 
     && iOfst>=(PENDING_BYTE+512) 
     && iOfst+iAmt<=PENDING_BYTE+p->nPagesize
    ){
      /* No-op. This special case is hit when the backup code is copying a
      ** to a database with a larger page-size than the source database and
      ** it needs to fill in the non-locking-region part of the original
      ** pending-byte page.
      */
    }else{
      u32 pgno = iOfst/p->nPagesize + 1;
      assert( (iAmt==1||iAmt==p->nPagesize) && ((iOfst+iAmt)%p->nPagesize)==0 );
      assert( pgno<=p->nPage || p->nSync>0 );
      assert( pgno>p->nPage || sqlite3BitvecTest(p->pWritable, pgno) );
    }
  }

  rc = sqlite3OsWrite(p->pReal, zBuf, iAmt, iOfst);
  if( (p->flags&SQLITE_OPEN_MAIN_JOURNAL) && iAmt==12 ){
    jt_file *pMain = locateDatabaseHandle(p->zName);
    int rc2 = readJournalFile(p, pMain);
    if( rc==SQLITE_OK ) rc = rc2;
  }
  return rc;
}

/*
** Truncate an jt-file.
*/
static int jtTruncate(sqlite3_file *pFile, sqlite_int64 size){
  jt_file *p = (jt_file *)pFile;
  if( p->flags&SQLITE_OPEN_MAIN_JOURNAL && size==0 ){
    /* Truncating a journal file. This is the end of a transaction. */
    jt_file *pMain = locateDatabaseHandle(p->zName);
    closeTransaction(pMain);
  }
  if( p->flags&SQLITE_OPEN_MAIN_DB && p->pWritable ){
    u32 pgno;
    u32 locking_page = (u32)(PENDING_BYTE/p->nPagesize+1);
    for(pgno=size/p->nPagesize+1; pgno<=p->nPage; pgno++){
      assert( pgno==locking_page || sqlite3BitvecTest(p->pWritable, pgno) );
    }
  }
  return sqlite3OsTruncate(p->pReal, size);
}

/*
** Sync an jt-file.
*/
static int jtSync(sqlite3_file *pFile, int flags){
  jt_file *p = (jt_file *)pFile;

  if( p->flags&SQLITE_OPEN_MAIN_JOURNAL ){