_processContent() and _processContainers()

protected function _processContent($content)
{
    $containers = $this->_processContainers($content);
    $isProcessed = empty($containers);
    // renew session cookie
    $sessionInfo = Enterprise_PageCache_Model_Cache::getCacheInstance()->load($this->getSessionInfoCacheId());

    if ($sessionInfo) {
        $sessionInfo = unserialize($sessionInfo);
        foreach ($sessionInfo as $cookieName => $cookieInfo) {
            if (isset($_COOKIE[$cookieName]) && isset($cookieInfo['lifetime'])
                && isset($cookieInfo['path']) && isset($cookieInfo['domain'])
                && isset($cookieInfo['secure']) && isset($cookieInfo['httponly'])
            ) {
                $lifeTime = (0 == $cookieInfo['lifetime']) ? 0 : time() + $cookieInfo['lifetime'];
                setcookie($cookieName, $_COOKIE[$cookieName], $lifeTime,
                    $cookieInfo['path'], $cookieInfo['domain'],
                    $cookieInfo['secure'], $cookieInfo['httponly']
                );
            }
        }
    } else {
        $isProcessed = false;
    }

    /**
     * restore session_id in content whether content is completely processed or not
     */
    $sidCookieName = $this->getMetadata('sid_cookie_name');
    $sidCookieValue = $sidCookieName && isset($_COOKIE[$sidCookieName]) ? $_COOKIE[$sidCookieName] : '';
    Enterprise_PageCache_Helper_Url::restoreSid($content, $sidCookieValue);

    if ($isProcessed) {
        return $content;
    } else {
        Mage::register('cached_page_content', $content);
        Mage::register('cached_page_containers', $containers);
        Mage::app()->getRequest()
            ->setModuleName('pagecache')
            ->setControllerName('request')
            ->setActionName('process')
            ->isStraight(true);

        // restore original routing info
        $routingInfo = array(
            'aliases'              => $this->getMetadata('routing_aliases'),
            'requested_route'      => $this->getMetadata('routing_requested_route'),
            'requested_controller' => $this->getMetadata('routing_requested_controller'),
            'requested_action'     => $this->getMetadata('routing_requested_action')
        );

        Mage::app()->getRequest()->setRoutingInfo($routingInfo);
        return false;
    }
}

protected function _processContainers(&$content)
{
    $placeholders = array();
    preg_match_all(
        Enterprise_PageCache_Model_Container_Placeholder::HTML_NAME_PATTERN,
        $content, $placeholders, PREG_PATTERN_ORDER
    );
    $placeholders = array_unique($placeholders[1]);
    $containers = array();
    foreach ($placeholders as $definition) {
        $placeholder = new Enterprise_PageCache_Model_Container_Placeholder($definition);
        $container = $placeholder->getContainerClass();
        if (!$container) {
            continue;
        }

        $container = new $container($placeholder);
        $container->setProcessor($this);
        if (!$container->applyWithoutApp($content)) {
            $containers[] = $container;
        } else {
            preg_match($placeholder->getPattern(), $content, $matches);
            if (array_key_exists(1,$matches)) {
                $containers = array_merge($this->_processContainers($matches[1]), $containers);
                $content = preg_replace($placeholder->getPattern(), str_replace('$', '\\$', $matches[1]), $content);
            }
        }
    }
    return $containers;
}