/*
** 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);
    if( rc!=SQLITE_OK 
     || decodeJournalHdr(zBuf, &nRec, &nPage, &nSector, &nPagesize) 
    ){
      goto finish_rjf;
    }
    iOff += nSector;

    if( nRec==0 ){
      /* A trick. There might be another journal-header immediately 
      ** following this one. In this case, 0 records means 0 records, 
      ** not "read until the end of the file". See also ticket #2565.
      */
      if( iSize>=(iOff+nSector) ){
        rc = sqlite3OsRead(pReal, zBuf, 28, iOff);
        if( rc!=SQLITE_OK || 0==decodeJournalHdr(zBuf, 0, 0, 0, 0) ){
          continue;
        }
      }
      nRec = (iSize-iOff) / (pMain->nPagesize+8);
    }

    /* Read all the records that follow the journal-header just read. */
    for(ii=0; rc==SQLITE_OK && ii<nRec && iOff<iSize; ii++){
      u32 pgno;
      rc = sqlite3OsRead(pReal, zBuf, 4, iOff);
      if( rc==SQLITE_OK ){
        pgno = decodeUint32(zBuf);
        if( pgno>0 && pgno<=pMain->nPage ){
          if( 0==sqlite3BitvecTest(pMain->pWritable, pgno) ){
            rc = sqlite3OsRead(pReal, aPage, pMain->nPagesize, iOff+4);
            if( rc==SQLITE_OK ){
              u32 cksum = genCksum(aPage, pMain->nPagesize);
              assert( cksum==pMain->aCksum[pgno-1] );
            }
          }
          sqlite3BitvecSet(pMain->pWritable, pgno);
        }
        iOff += (8 + pMain->nPagesize);
      }
    }

    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;
}
Esempio n. 2
0
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;

    
    rc = sqlite3OsRead(pReal, zBuf, 28, iOff);
    if( rc!=SQLITE_OK 
     || decodeJournalHdr(zBuf, &nRec, &nPage, &nSector, &nPagesize) 
    ){
      goto finish_rjf;
    }
    iOff += nSector;

    if( nRec==0 ){
      if( iSize>=(iOff+nSector) ){
        rc = sqlite3OsRead(pReal, zBuf, 28, iOff);
        if( rc!=SQLITE_OK || 0==decodeJournalHdr(zBuf, 0, 0, 0, 0) ){
          continue;
        }
      }
      nRec = (iSize-iOff) / (pMain->nPagesize+8);
    }

    
    for(ii=0; rc==SQLITE_OK && ii<nRec && iOff<iSize; ii++){
      u32 pgno;
      rc = sqlite3OsRead(pReal, zBuf, 4, iOff);
      if( rc==SQLITE_OK ){
        pgno = decodeUint32(zBuf);
        if( pgno>0 && pgno<=pMain->nPage ){
          if( 0==sqlite3BitvecTest(pMain->pWritable, pgno) ){
            rc = sqlite3OsRead(pReal, aPage, pMain->nPagesize, iOff+4);
            if( rc==SQLITE_OK ){
              u32 cksum = genCksum(aPage, pMain->nPagesize);
              assert( cksum==pMain->aCksum[pgno-1] );
            }
          }
          sqlite3BitvecSet(pMain->pWritable, pgno);
        }
        iOff += (8 + pMain->nPagesize);
      }
    }

    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;
}