ecshop改了模板类使用memcached之后如何判断调用成功

/**
     * 处理模板文件
     *
     * @access  public
     * @param   string      $filename
     * @param   sting      $cache_id
     *
     * @return  sring
     */
    function fetch($filename, $cache_id = '')
    {
        if (!$this->_seterror)
        {
            error_reporting(E_ALL ^ E_NOTICE);
        }
        $this->_seterror++;

        if (strncmp($filename,'str:', 4) == 0)
        {
            $out = $this->_eval($this->fetch_str(substr($filename, 4)));
        }
        else
        {
            if ($this->_checkfile)
            {
                if (!file_exists($filename))
                {
                    $filename = $this->template_dir . '/' . $filename;
                }
            }
            else
            {
                $filename = $this->template_dir . '/' . $filename;
            }

            if ($this->direct_output)
            {
                $this->_current_file = $filename;

                $out = $this->_eval($this->fetch_str(file_get_contents($filename)));
            }
            else
            {
                if ($cache_id && $this->caching)
                {
                    $out = $this->template_out;
                }
                else
                {
                    if (!in_array($filename, $this->template))
                    {
                        $this->template[] = $filename;
                    }

                    $out = $this->make_compiled($filename);

                    if ($cache_id)
                    {
                        $cachename = basename($filename, strrchr($filename, '.')) . '_' . $cache_id;
                        $data = serialize(array('template' => $this->template, 'expires' => $this->_nowtime + $this->cache_lifetime, 'maketime' => $this->_nowtime));
                        $out = str_replace("\r", '', $out);
						
						$memcache = new Memcache;
						$memcache->connect("127.0.0.1", 11211);
						$CacheID = md5($filename.$cache_id.$cachename);

                        while (strpos($out, "\n\n") !== false)
                        {
                            $out = str_replace("\n\n", "\n", $out);
                        }
						
						$memcache->set($CacheID , '' . $data . $out , 3600);
						
                        $this->template = array();
                    }
                }
            }
        }

        $this->_seterror--;
        if (!$this->_seterror)
        {
            error_reporting($this->_errorlevel);
        }

        return $out; // 返回html数据
    }

/**
     * 判断是否缓存
     *
     * @access  public
     * @param   string     $filename
     * @param   sting      $cache_id
     *
     * @return  bool
     */
    function is_cached($filename, $cache_id = '')
    {
        $cachename = basename($filename, strrchr($filename, '.')) . '_' . $cache_id;
		
		$memcache = new Memcache;
		$memcache->connect("127.0.0.1", 11211);
		$CacheID = md5($filename.$cache_id.$cachename);
		
        if ($this->caching == true && $this->direct_output == false)
        {
			if ($data = $memcache->get($CacheID))
            {
                $data = substr($data, 13);
                $pos  = strpos($data, '<');
                $paradata = substr($data, 0, $pos);
                $para     = @unserialize($paradata);
                if ($para === false || $this->_nowtime > $para['expires'])
                {
                    $this->caching = false;

                    return false;
                }
                $this->_expires = $para['expires'];

                $this->template_out = substr($data, $pos);

                foreach ($para['template'] AS $val)
                {
                    $stat = @stat($val);
                    if ($para['maketime'] < $stat['mtime'])
                    {
                        $this->caching = false;

                        return false;
                    }
                }
            }
            else
            {
                $this->caching = false;

                return false;
            }

            return true;
        }
        else
        {
            return false;
        }
    }