public function fetch($id)
    {
        if (!$this->locking) {
            return file_get_contents($this->path . '/' . $id);
        }

        $fp = fopen($this->path . '/' . $id, 'rb');
        if (!$fp) {
            return false;
        }

        flock($fp, LOCK_SH);
        $ret = stream_get_contents($fp);
        flock($fp, LOCK_UN);
        fclose($fp);

        return $ret;
    }