protected function fetch($cid, $resource_name = null, $cache_id = null, $compile_id = null, &$content = null, &$timestamp = null, $resource_uid = null)
    {
        $t = $this->read(array($cid));
        $content = !empty($t[$cid]) ? $t[$cid] : null;
        $timestamp = null;

        if ($content && ($timestamp = $this->getMetaTimestamp($content))) {
            $invalidated = $this->getLatestInvalidationTimestamp($cid, $resource_name, $cache_id, $compile_id, $resource_uid);
            if ($invalidated > $timestamp) {
                $timestamp = null;
                $content = null;
            }
        }

        return !!$content;
    }