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Overview
Comment:Relax an over-zealous assert() in sqlite3WalUndo().
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SHA1: 8f9d22d58c75ad7476c1eea8ba296347e30b7beb
User & Date: drh 2010-05-04 17:20:09.000
Context
2010-05-04
17:38
Be sure to release all wal-index locks before closing the wal-index. (check-in: b15b67fa14 user: drh tags: trunk)
17:20
Relax an over-zealous assert() in sqlite3WalUndo(). (check-in: 8f9d22d58c user: drh tags: trunk)
16:33
Take care not to invoke the xShmClose method of the VFS with a NULL shared memory object. (check-in: 1465d3842c user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/wal.c.
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  }else if( pWal->lockState==SQLITE_SHM_WRITE ){
    rc = walSetLock(pWal, SQLITE_SHM_READ);
  }
  return rc;
}

/*
** The Wal object passed to this function must be holding the write-lock.
**
** If any data has been written (but not committed) to the log file, this
** function moves the write-pointer back to the start of the transaction.
**
** Additionally, the callback function is invoked for each frame written
** to the log since the start of the transaction. If the callback returns
** other than SQLITE_OK, it is not invoked again and the error code is
** returned to the caller.
**
** Otherwise, if the callback function does not return an error, this
** function returns SQLITE_OK.
*/
int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
  int rc = SQLITE_OK;
  Pgno iMax = pWal->hdr.iLastPg;
  Pgno iFrame;

  assert( pWal->lockState==SQLITE_SHM_WRITE );
  walIndexReadHdr(pWal, 0);
  for(iFrame=pWal->hdr.iLastPg+1; iFrame<=iMax && rc==SQLITE_OK; iFrame++){

    rc = xUndo(pUndoCtx, pWal->pWiData[walIndexEntry(iFrame)]);
  }
  walIndexUnmap(pWal);
  return rc;
}

/* Return an integer that records the current (uncommitted) write








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  }else if( pWal->lockState==SQLITE_SHM_WRITE ){
    rc = walSetLock(pWal, SQLITE_SHM_READ);
  }
  return rc;
}

/*


** If any data has been written (but not committed) to the log file, this
** function moves the write-pointer back to the start of the transaction.
**
** Additionally, the callback function is invoked for each frame written
** to the log since the start of the transaction. If the callback returns
** other than SQLITE_OK, it is not invoked again and the error code is
** returned to the caller.
**
** Otherwise, if the callback function does not return an error, this
** function returns SQLITE_OK.
*/
int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
  int rc = SQLITE_OK;
  Pgno iMax = pWal->hdr.iLastPg;
  Pgno iFrame;


  walIndexReadHdr(pWal, 0);
  for(iFrame=pWal->hdr.iLastPg+1; iFrame<=iMax && rc==SQLITE_OK; iFrame++){
    assert( pWal->lockState==SQLITE_SHM_WRITE );
    rc = xUndo(pUndoCtx, pWal->pWiData[walIndexEntry(iFrame)]);
  }
  walIndexUnmap(pWal);
  return rc;
}

/* Return an integer that records the current (uncommitted) write
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