<?php /** * @link http://www.yiiframework.com/ * @copyright Copyright (c) 2008 Yii Software LLC * @license http://www.yiiframework.com/license/ */ namespace yii\caching; /** * TagDependency associates a cached data item with one or multiple [[tags]]. * * By calling [[invalidate()]], you can invalidate all cached data items that are associated with the specified tag name(s). * * @author Qiang Xue <qiang.xue@gmail.com> * @since 2.0 */ class TagDependency extends Dependency { /** * @var string|array a list of tag names for this dependency. For a single tag, you may specify it as a string. */ public $tags = []; /** * Generates the data needed to determine if dependency has been changed. * This method does nothing in this class. * @param Cache $cache the cache component that is currently evaluating this dependency * @return mixed the data needed to determine if dependency has been changed. */ protected function generateDependencyData($cache) { $timestamps = $this->getTimestamps($cache, (array) $this->tags); $newKeys = []; foreach ($timestamps as $key => $timestamp) { if ($timestamp === false) { $newKeys[] = $key; } } if (!empty($newKeys)) { $timestamps = array_merge($timestamps, $this->touchKeys($cache, $newKeys)); } return $timestamps; } /** * Performs the actual dependency checking. * @param Cache $cache the cache component that is currently evaluating this dependency * @return boolean whether the dependency is changed or not. */ public function getHasChanged($cache) { $timestamps = $this->getTimestamps($cache, (array) $this->tags); return $timestamps !== $this->data; } /** * Invalidates all of the cached data items that are associated with any of the specified [[tags]]. * @param Cache $cache the cache component that caches the data items * @param string|array $tags */ public static function invalidate($cache, $tags) { $keys = []; foreach ((array) $tags as $tag) { $keys[] = $cache->buildKey([__CLASS__, $tag]); } static::touchKeys($cache, $keys); } /** * Generates the timestamp for the specified cache keys. * @param Cache $cache * @param string[] $keys * @return array the timestamp indexed by cache keys */ protected static function touchKeys($cache, $keys) { $items = []; $time = microtime(); foreach ($keys as $key) { $items[$key] = $time; } $cache->mset($items); return $items; } /** * Returns the timestamps for the specified tags. * @param Cache $cache * @param string[] $tags * @return array the timestamps indexed by the specified tags. */ protected function getTimestamps($cache, $tags) { if (empty($tags)) { return []; } $keys = []; foreach ($tags as $tag) { $keys[] = $cache->buildKey([__CLASS__, $tag]); } return $cache->mget($keys); } }