@Override
  public HashStamp getPreviousStamp(File file, BuildTarget<?> target) throws IOException {
    FileTimestamp previousTimestamp = myTimestampStorage.getPreviousStamp(file, target);
    HashStampPerTarget[] state = getState(relativePath(file));
    if (state != null) {
      int targetId = myTargetsState.getBuildTargetId(target);
      for (HashStampPerTarget filesStampPerTarget : state) {
        if (filesStampPerTarget.targetId == targetId) {
          return new HashStamp(filesStampPerTarget.hash, previousTimestamp.asLong());
        }
      }
    }
    return HashStamp.EMPTY;
  }
@Override
  public HashStamp getPreviousStamp(File file, BuildTarget<?> target)