COutputCache

protected function checkContentCache()
{
    if((empty($this->requestTypes) || in_array(Yii::app()->getRequest()->getRequestType(),$this->requestTypes))
        && ($this->_cache=$this->getCache())!==null)
    {
        if($this->duration>0 && ($data=$this->_cache->get($this->getCacheKey()))!==false)
        {
            $this->_content=$data[0];
            $this->_actions=$data[1];
            return true;
        }
        if($this->duration==0)
            $this->_cache->delete($this->getCacheKey());
        if($this->duration<=0)
            $this->_cache=null;
    }
    return false;
}

public function filter($filterChain)
{
    if(!$this->getIsContentCached())
        $filterChain->run();
    $this->run();
}

protected function getBaseCacheKey()
{
    return self::CACHE_KEY_PREFIX.$this->getId().'.';
}

protected function getCache()
{
    return Yii::app()->getComponent($this->cacheID);
}

protected function getCacheKey()
{
    if($this->_key!==null)
        return $this->_key;
    else
    {
        $key=$this->getBaseCacheKey().'.';
        if($this->varyByRoute)
        {
            $controller=$this->getController();
            $key.=$controller->getUniqueId().'/';
            if(($action=$controller->getAction())!==null)
                $key.=$action->getId();
        }
        $key.='.';

        if($this->varyBySession)
            $key.=Yii::app()->getSession()->getSessionID();
        $key.='.';

        if(is_array($this->varyByParam) && isset($this->varyByParam[0]))
        {
            $params=array();
            foreach($this->varyByParam as $name)
            {
                if(isset($_GET[$name]))
                    $params[$name]=$_GET[$name];
                else
                    $params[$name]='';
            }
            $key.=serialize($params);
        }
        $key.='.';

        if($this->varyByExpression!==null)
            $key.=$this->evaluateExpression($this->varyByExpression);
        $key.='.';

        return $this->_key=$key;
    }
}

public function getIsContentCached()
{
    if($this->_contentCached!==null)
        return $this->_contentCached;
    else
        return $this->_contentCached=$this->checkContentCache();
}

public function init()
{
    if($this->getIsContentCached())
        $this->replayActions();
    else if($this->_cache!==null)
    {
        $this->getController()->getCachingStack()->push($this);
        ob_start();
        ob_implicit_flush(false);
    }
}

public function recordAction($context,$method,$params)
{
    $this->_actions[]=array($context,$method,$params);
}

protected function replayActions()
{
    if(empty($this->_actions))
        return;
    $controller=$this->getController();
    $cs=Yii::app()->getClientScript();
    foreach($this->_actions as $action)
    {
        if($action[0]==='clientScript')
            $object=$cs;
        else if($action[0]==='')
            $object=$controller;
        else
            $object=$controller->{$action[0]};
        if(method_exists($object,$action[1]))
            call_user_func_array(array($object,$action[1]),$action[2]);
        else if($action[0]==='' && function_exists($action[1]))
            call_user_func_array($action[1],$action[2]);
        else
            throw new CException(Yii::t('yii','Unable to replay the action "{object}.{method}". The method does not exist.',
                array('object'=>$action[0],
                    'method'=>$action[1])));
    }
}

public function run()
{
    if($this->getIsContentCached())
    {
        if($this->getController()->isCachingStackEmpty())
            echo $this->getController()->processDynamicOutput($this->_content);
        else
            echo $this->_content;
    }
    else if($this->_cache!==null)
    {
        $this->_content=ob_get_clean();
        $this->getController()->getCachingStack()->pop();
        $data=array($this->_content,$this->_actions);
        if(is_array($this->dependency))
            $this->dependency=Yii::createComponent($this->dependency);
        $this->_cache->set($this->getCacheKey(),$data,$this->duration,$this->dependency);

        if($this->getController()->isCachingStackEmpty())
            echo $this->getController()->processDynamicOutput($this->_content);
        else
            echo $this->_content;
    }
}