How does «Flush Cache Storage» work?

dmitry_fedyuk · June 29, 2017, 9:56pm

1. Magento\Backend\Block\Cache::_construct()

magento/magento2/blob/2.2.0-RC1.1/app/code/Magento/Backend/Block/Cache.php#L34-L41


$this->buttonList->add(
    'flush_system',
    [
        'label' => __('Flush Cache Storage'),
        'onclick' => 'confirmSetLocation(\'' . $message . '\', \'' . $this->getFlushStorageUrl() . '\')',
        'class' => 'flush-cache-storage'
    ]
);

2. Magento\Backend\Block\Cache::getFlushStorageUrl()

github.com

magento/magento2/blob/2.2.0-RC1.1/app/code/Magento/Backend/Block/Cache.php#L44-L52


/**
 * Get url for clean cache storage
 *
 * @return string
 */
public function getFlushStorageUrl()
{
    return $this->getUrl('adminhtml/*/flushAll');
}

3. Magento\Backend\Controller\Adminhtml\Cache\FlushAll::execute()

github.com

magento/magento2/blob/2.2.0-RC1.1/app/code/Magento/Backend/Controller/Adminhtml/Cache/FlushAll.php#L19-L22


/** @var $cacheFrontend \Magento\Framework\Cache\FrontendInterface */
foreach ($this->_cacheFrontendPool as $cacheFrontend) {
    $cacheFrontend->getBackend()->clean();
}

4. Magento\Framework\Cache\Frontend\Decorator\Bare::getBackend()

github.com

magento/magento2/blob/2.2.0-RC1.1/lib/internal/Magento/Framework/Cache/Frontend/Decorator/Bare.php#L94-L100


/**
 * {@inheritdoc}
 */
public function getBackend()
{
    return $this->_getFrontend()->getBackend();
}

5. Cm_Cache_Backend_File::clean()

github.com

colinmollenhour/Cm_Cache_Backend_File/blob/1.4/File.php#L201-L229


/**
 * Clean some cache records
 *
 * Available modes are :
 * 'all' (default)  => remove all cache entries ($tags is not used)
 * 'old'            => remove too old cache entries ($tags is not used)
 * 'matchingTag'    => remove cache entries matching all given tags
 *                     ($tags can be an array of strings or a single string)
 * 'notMatchingTag' => remove cache entries not matching one of the given tags
 *                     ($tags can be an array of strings or a single string)
 * 'matchingAnyTag' => remove cache entries matching any given tags
 *                     ($tags can be an array of strings or a single string)
 *
 * @param string $mode
 * @param array $tags
 * @return boolean true if no problem
 */
public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array())
{
    // We use this protected method to hide the recursive stuff
    clearstatcache();
    switch($mode) {
        case Zend_Cache::CLEANING_MODE_ALL:
        case Zend_Cache::CLEANING_MODE_OLD:
            return $this->_clean($this->_options['cache_dir'], $mode);
        default:
            return $this->_cleanNew($mode, $tags);
    }
}

Cm_Cache_Backend_File::_clean()

github.com

colinmollenhour/Cm_Cache_Backend_File/blob/1.4/File.php#L414-L486


/**
 * Clean some cache records (protected method used for recursive stuff)
 *
 * Available modes are :
 * Zend_Cache::CLEANING_MODE_ALL (default)    => remove all cache entries ($tags is not used)
 * Zend_Cache::CLEANING_MODE_OLD              => remove too old cache entries ($tags is not used)
 * Zend_Cache::CLEANING_MODE_MATCHING_TAG     => remove cache entries matching all given tags
 *                                               ($tags can be an array of strings or a single string)
 * Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG => remove cache entries not {matching one of the given tags}
 *                                               ($tags can be an array of strings or a single string)
 * Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG => remove cache entries matching any given tags
 *                                               ($tags can be an array of strings or a single string)
 *
 * @param string $dir  Directory to clean
 * @param string $mode Clean mode
 * @param array $tags
 * @throws Zend_Cache_Exception
 * @return boolean True if no problem
 */
protected function _clean($dir, $mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array())
{
    if (!is_dir($dir)) {
        return false;
    }
    $result = true;
    $glob = @glob($dir . $this->_options['file_name_prefix'] . '--*');
    if ($glob === false) {
        return true;
    }
    foreach ($glob as $file)  {
        if (is_file($file)) {
            if ($mode == Zend_Cache::CLEANING_MODE_ALL) {
                $result = @unlink($file) && $result;
                continue;
            }


            $id = $this->_fileNameToId(basename($file));
            $_file = $this->_file($id);
            if ($file != $_file) {
                @unlink($file);
                continue;
            }
            $metadatas = $this->_getCache($file, false);
            if ( ! $metadatas) {
                @unlink($file);
                continue;
            }
            if ($mode == Zend_Cache::CLEANING_MODE_OLD) {
                if (time() > $metadatas['expire']) {
                    $result = $this->_remove($file) && $result;
                    $result = $this->_updateIdsTags(array($id), explode(',', $metadatas['tags']), 'diff') && $result;
                }
                continue;
            } else {
                Zend_Cache::throwException('Invalid mode for clean() method.');
            }
        }
        if ((is_dir($file)) and ($this->_options['hashed_directory_level']>0)) {
            // Recursive call
            $result = $this->_clean($file . DIRECTORY_SEPARATOR, $mode) && $result;
            if ($mode == 'all') {
                // if mode=='all', we try to drop the structure too
                @rmdir($file);
            }
        }
    }
    if ($mode == 'all') {
        foreach (glob($this->_tagFile('*')) as $tagFile) {
            @unlink($tagFile);
        }
    }
    return $result;
}

dmitry_fedyuk · June 29, 2017, 10:09pm