protected function tryGetFromStatCache(&$stat_result) {
    if (!$this->hash_value) {
      $this->hash_value = self::getHashValue($this->filename);
    }

    if (array_key_exists($this->hash_value, self::$stat_cache)) {
      $stat_result = self::$stat_cache[$this->hash_value];
      return true;
    }
    return false;
  }