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Yii原始碼分析之ApcCache

ApcCache根據應用程式元件提供APC快取。

要使用此應用程式元件,必須載入APC PHP擴充套件。或者,可以通過將useApcu設定為true來使用APCu PHP擴充套件。要為CLI啟用APC或APCu,您應該在php.ini中新增“apc.enable_cli = 1”。

有關ApcCache支援的常見快取操作,請參閱yii \ caching \ Cache。

我們看下其原始碼:

<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\caching;

use yii\base\InvalidConfigException;

/**
 * ApcCache provides APC caching in terms of an application component.
 *
 * To use this application component, the [APC PHP extension](http://www.php.net/apc) must be loaded.
 * Alternatively [APCu PHP extension](http://www.php.net/apcu) could be used via setting `useApcu` to `true`.
 * In order to enable APC or APCu for CLI you should add "apc.enable_cli = 1" to your php.ini.
 *
 * See [[Cache]] for common cache operations that ApcCache supports.
 *
 * For more details and usage information on Cache, see the [guide article on caching](guide:caching-overview).
 *
 * @author Qiang Xue <
[email protected]
> * @since 2.0 */ class ApcCache extends Cache { /** * @var bool whether to use apcu or apc as the underlying caching extension. * If true, [apcu](http://pecl.php.net/package/apcu) will be used. * If false, [apc](http://pecl.php.net/package/apc) will be used. * Defaults to false. * @since 2.0.7 */ public $useApcu = false; /** * Initializes this application component. * It checks if extension required is loaded. */ public function init() { parent::init(); $extension = $this->useApcu ? 'apcu' : 'apc'; if (!extension_loaded($extension)) { throw new InvalidConfigException("ApcCache requires PHP $extension extension to be loaded."); } } /** * Checks whether a specified key exists in the cache. * This can be faster than getting the value from the cache if the data is big. * Note that this method does not check whether the dependency associated * with the cached data, if there is any, has changed. So a call to [[get]] * may return false while exists returns true. * @param mixed $key a key identifying the cached value. This can be a simple string or * a complex data structure consisting of factors representing the key. * @return bool true if a value exists in cache, false if the value is not in the cache or expired. */ public function exists($key) { $key = $this->buildKey($key); return $this->useApcu ? apcu_exists($key) : apc_exists($key); } /** * Retrieves a value from cache with a specified key. * This is the implementation of the method declared in the parent class. * @param string $key a unique key identifying the cached value * @return mixed|false the value stored in cache, false if the value is not in the cache or expired. */ protected function getValue($key) { return $this->useApcu ? apcu_fetch($key) : apc_fetch($key); } /** * Retrieves multiple values from cache with the specified keys. * @param array $keys a list of keys identifying the cached values * @return array a list of cached values indexed by the keys */ protected function getValues($keys) { $values = $this->useApcu ? apcu_fetch($keys) : apc_fetch($keys); return is_array($values) ? $values : []; } /** * Stores a value identified by a key in cache. * This is the implementation of the method declared in the parent class. * * @param string $key the key identifying the value to be cached * @param mixed $value the value to be cached. Most often it's a string. If you have disabled [[serializer]], * it could be something else. * @param int $duration the number of seconds in which the cached value will expire. 0 means never expire. * @return bool true if the value is successfully stored into cache, false otherwise. */ protected function setValue($key, $value, $duration) { return $this->useApcu ? apcu_store($key, $value, $duration) : apc_store($key, $value, $duration); } /** * Stores multiple key-value pairs in cache. * @param array $data array where key corresponds to cache key while value * @param int $duration the number of seconds in which the cached values will expire. 0 means never expire. * @return array array of failed keys */ protected function setValues($data, $duration) { $result = $this->useApcu ? apcu_store($data, null, $duration) : apc_store($data, null, $duration); return is_array($result) ? array_keys($result) : []; } /** * Stores a value identified by a key into cache if the cache does not contain this key. * This is the implementation of the method declared in the parent class. * @param string $key the key identifying the value to be cached * @param mixed $value the value to be cached. Most often it's a string. If you have disabled [[serializer]], * it could be something else. * @param int $duration the number of seconds in which the cached value will expire. 0 means never expire. * @return bool true if the value is successfully stored into cache, false otherwise */ protected function addValue($key, $value, $duration) { return $this->useApcu ? apcu_add($key, $value, $duration) : apc_add($key, $value, $duration); } /** * Adds multiple key-value pairs to cache. * @param array $data array where key corresponds to cache key while value is the value stored * @param int $duration the number of seconds in which the cached values will expire. 0 means never expire. * @return array array of failed keys */ protected function addValues($data, $duration) { $result = $this->useApcu ? apcu_add($data, null, $duration) : apc_add($data, null, $duration); return is_array($result) ? array_keys($result) : []; } /** * Deletes a value with the specified key from cache * This is the implementation of the method declared in the parent class. * @param string $key the key of the value to be deleted * @return bool if no error happens during deletion */ protected function deleteValue($key) { return $this->useApcu ? apcu_delete($key) : apc_delete($key); } /** * Deletes all values from cache. * This is the implementation of the method declared in the parent class. * @return bool whether the flush operation was successful. */ protected function flushValues() { return $this->useApcu ? apcu_clear_cache() : apc_clear_cache('user'); } }