Subversion Repositories SmartDukaan

<?php

/**

 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)

 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)

 *

 * Licensed under The MIT License

 * For full copyright and license information, please see the LICENSE.txt

 * Redistributions of files must retain the above copyright notice.

 *

 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)

 * @link          http://cakephp.org CakePHP(tm) Project

 * @package       Cake.Cache

 * @since         CakePHP(tm) v 1.2.0.4933

 * @license       http://www.opensource.org/licenses/mit-license.php MIT License

 */

App::uses('Inflector', 'Utility');

App::uses('CacheEngine', 'Cache');

/**

 * Cache provides a consistent interface to Caching in your application. It allows you

 * to use several different Cache engines, without coupling your application to a specific

 * implementation. It also allows you to change out cache storage or configuration without effecting

 * the rest of your application.

 *

 * You can configure Cache engines in your application's `bootstrap.php` file. A sample configuration would

 * be

 *

 * ```

 *	Cache::config('shared', array(

 *		'engine' => 'Apc',

 *		'prefix' => 'my_app_'

 *  ));

 * ```

 *

 * This would configure an APC cache engine to the 'shared' alias. You could then read and write

 * to that cache alias by using it for the `$config` parameter in the various Cache methods. In

 * general all Cache operations are supported by all cache engines. However, Cache::increment() and

 * Cache::decrement() are not supported by File caching.

 *

 * @package       Cake.Cache

 */

class Cache {

/**

 * Cache configuration stack

 * Keeps the permanent/default settings for each cache engine.

 * These settings are used to reset the engines after temporary modification.

 *

 * @var array

 */

	protected static $_config = array();

/**

 * Group to Config mapping

 *

 * @var array

 */

	protected static $_groups = array();

/**

 * Whether to reset the settings with the next call to Cache::set();

 *

 * @var array

 */

	protected static $_reset = false;

/**

 * Engine instances keyed by configuration name.

 *

 * @var array

 */

	protected static $_engines = array();

/**

 * Set the cache configuration to use. config() can

 * both create new configurations, return the settings for already configured

 * configurations.

 *

 * To create a new configuration, or to modify an existing configuration permanently:

 *

 * `Cache::config('my_config', array('engine' => 'File', 'path' => TMP));`

 *

 * If you need to modify a configuration temporarily, use Cache::set().

 * To get the settings for a configuration:

 *

 * `Cache::config('default');`

 *

 * There are 5 built-in caching engines:

 *

 * - `FileEngine` - Uses simple files to store content. Poor performance, but good for

 *    storing large objects, or things that are not IO sensitive.

 * - `ApcEngine` - Uses the APC object cache, one of the fastest caching engines.

 * - `MemcacheEngine` - Uses the PECL::Memcache extension and Memcached for storage.

 *   Fast reads/writes, and benefits from memcache being distributed.

 * - `XcacheEngine` - Uses the Xcache extension, an alternative to APC.

 * - `WincacheEngine` - Uses Windows Cache Extension for PHP. Supports wincache 1.1.0 and higher.

 *

 * The following keys are used in core cache engines:

 *

 * - `duration` Specify how long items in this cache configuration last.

 * - `groups` List of groups or 'tags' associated to every key stored in this config.

 *    handy for deleting a complete group from cache.

 * - `prefix` Prefix appended to all entries. Good for when you need to share a keyspace

 *    with either another cache config or another application.

 * - `probability` Probability of hitting a cache gc cleanup. Setting to 0 will disable

 *    cache::gc from ever being called automatically.

 * - `servers' Used by memcache. Give the address of the memcached servers to use.

 * - `compress` Used by memcache. Enables memcache's compressed format.

 * - `serialize` Used by FileCache. Should cache objects be serialized first.

 * - `path` Used by FileCache. Path to where cachefiles should be saved.

 * - `lock` Used by FileCache. Should files be locked before writing to them?

 * - `user` Used by Xcache. Username for XCache

 * - `password` Used by Xcache/Redis. Password for XCache/Redis

 *

 * @param string $name Name of the configuration

 * @param array $settings Optional associative array of settings passed to the engine

 * @return array array(engine, settings) on success, false on failure

 * @throws CacheException

 * @see app/Config/core.php for configuration settings

 */

	public static function config($name = null, $settings = array()) {

		if (is_array($name)) {

			$settings = $name;

		}

		$current = array();

		if (isset(static::$_config[$name])) {

			$current = static::$_config[$name];

		}

		if (!empty($settings)) {

			static::$_config[$name] = $settings + $current;

		}

		if (empty(static::$_config[$name]['engine'])) {

			return false;

		}

		if (!empty(static::$_config[$name]['groups'])) {

			foreach (static::$_config[$name]['groups'] as $group) {

				static::$_groups[$group][] = $name;

				sort(static::$_groups[$group]);

				static::$_groups[$group] = array_unique(static::$_groups[$group]);

			}

		}

		$engine = static::$_config[$name]['engine'];

		if (!isset(static::$_engines[$name])) {

			static::_buildEngine($name);

			$settings = static::$_config[$name] = static::settings($name);

		} elseif ($settings = static::set(static::$_config[$name], null, $name)) {

			static::$_config[$name] = $settings;

		}

		return compact('engine', 'settings');

	}

/**

 * Finds and builds the instance of the required engine class.

 *

 * @param string $name Name of the config array that needs an engine instance built

 * @return bool

 * @throws CacheException

 */

	protected static function _buildEngine($name) {

		$config = static::$_config[$name];

		list($plugin, $class) = pluginSplit($config['engine'], true);

		$cacheClass = $class . 'Engine';

		App::uses($cacheClass, $plugin . 'Cache/Engine');

		if (!class_exists($cacheClass)) {

			throw new CacheException(__d('cake_dev', 'Cache engine %s is not available.', $name));

		}

		$cacheClass = $class . 'Engine';

		if (!is_subclass_of($cacheClass, 'CacheEngine')) {

			throw new CacheException(__d('cake_dev', 'Cache engines must use %s as a base class.', 'CacheEngine'));

		}

		static::$_engines[$name] = new $cacheClass();

		if (!static::$_engines[$name]->init($config)) {

			$msg = __d(

				'cake_dev',

				'Cache engine "%s" is not properly configured. Ensure required extensions are installed, and credentials/permissions are correct',

				$name

			);

			throw new CacheException($msg);

		}

		if (static::$_engines[$name]->settings['probability'] && time() % static::$_engines[$name]->settings['probability'] === 0) {

			static::$_engines[$name]->gc();

		}

		return true;

	}

/**

 * Returns an array containing the currently configured Cache settings.

 *

 * @return array Array of configured Cache config names.

 */

	public static function configured() {

		return array_keys(static::$_config);

	}

/**

 * Drops a cache engine. Deletes the cache configuration information

 * If the deleted configuration is the last configuration using a certain engine,

 * the Engine instance is also unset.

 *

 * @param string $name A currently configured cache config you wish to remove.

 * @return bool success of the removal, returns false when the config does not exist.

 */

	public static function drop($name) {

		if (!isset(static::$_config[$name])) {

			return false;

		}

		unset(static::$_config[$name], static::$_engines[$name]);

		return true;

	}

/**

 * Temporarily change the settings on a cache config. The settings will persist for the next write

 * operation (write, decrement, increment, clear). Any reads that are done before the write, will

 * use the modified settings. If `$settings` is empty, the settings will be reset to the

 * original configuration.

 *

 * Can be called with 2 or 3 parameters. To set multiple values at once.

 *

 * `Cache::set(array('duration' => '+30 minutes'), 'my_config');`

 *

 * Or to set one value.

 *

 * `Cache::set('duration', '+30 minutes', 'my_config');`

 *

 * To reset a config back to the originally configured values.

 *

 * `Cache::set(null, 'my_config');`

 *

 * @param string|array $settings Optional string for simple name-value pair or array

 * @param string $value Optional for a simple name-value pair

 * @param string $config The configuration name you are changing. Defaults to 'default'

 * @return array Array of settings.

 */

	public static function set($settings = array(), $value = null, $config = 'default') {

		if (is_array($settings) && $value !== null) {

			$config = $value;

		}

		if (!isset(static::$_config[$config]) || !isset(static::$_engines[$config])) {

			return false;

		}

		if (!empty($settings)) {

			static::$_reset = true;

		}

		if (static::$_reset === true) {

			if (empty($settings)) {

				static::$_reset = false;

				$settings = static::$_config[$config];

			} else {

				if (is_string($settings) && $value !== null) {

					$settings = array($settings => $value);

				}

				$settings += static::$_config[$config];

				if (isset($settings['duration']) && !is_numeric($settings['duration'])) {

					$settings['duration'] = strtotime($settings['duration']) - time();

				}

			}

			static::$_engines[$config]->settings = $settings;

		}

		return static::settings($config);

	}

/**

 * Garbage collection

 *

 * Permanently remove all expired and deleted data

 *

 * @param string $config [optional] The config name you wish to have garbage collected. Defaults to 'default'

 * @param int $expires [optional] An expires timestamp. Defaults to NULL

 * @return void

 */

	public static function gc($config = 'default', $expires = null) {

		static::$_engines[$config]->gc($expires);

	}

/**

 * Write data for key into a cache engine.

 *

 * ### Usage:

 *

 * Writing to the active cache config:

 *

 * `Cache::write('cached_data', $data);`

 *

 * Writing to a specific cache config:

 *

 * `Cache::write('cached_data', $data, 'long_term');`

 *

 * @param string $key Identifier for the data

 * @param mixed $value Data to be cached - anything except a resource

 * @param string $config Optional string configuration name to write to. Defaults to 'default'

 * @return bool True if the data was successfully cached, false on failure

 */

	public static function write($key, $value, $config = 'default') {

		$settings = static::settings($config);

		if (empty($settings)) {

			return false;

		}

		if (!static::isInitialized($config)) {

			return false;

		}

		$key = static::$_engines[$config]->key($key);

		if (!$key || is_resource($value)) {

			return false;

		}

		$success = static::$_engines[$config]->write($settings['prefix'] . $key, $value, $settings['duration']);

		static::set(null, $config);

		if ($success === false && $value !== '') {

			trigger_error(

				__d('cake_dev',

					"%s cache was unable to write '%s' to %s cache",

					$config,

					$key,

					static::$_engines[$config]->settings['engine']

				),

				E_USER_WARNING

			);

		}

		return $success;

	}

/**

 * Read a key from a cache config.

 *

 * ### Usage:

 *

 * Reading from the active cache configuration.

 *

 * `Cache::read('my_data');`

 *

 * Reading from a specific cache configuration.

 *

 * `Cache::read('my_data', 'long_term');`

 *

 * @param string $key Identifier for the data

 * @param string $config optional name of the configuration to use. Defaults to 'default'

 * @return mixed The cached data, or false if the data doesn't exist, has expired, or if there was an error fetching it

 */

	public static function read($key, $config = 'default') {

		$settings = static::settings($config);

		if (empty($settings)) {

			return false;

		}

		if (!static::isInitialized($config)) {

			return false;

		}

		$key = static::$_engines[$config]->key($key);

		if (!$key) {

			return false;

		}

		return static::$_engines[$config]->read($settings['prefix'] . $key);

	}

/**

 * Increment a number under the key and return incremented value.

 *

 * @param string $key Identifier for the data

 * @param int $offset How much to add

 * @param string $config Optional string configuration name. Defaults to 'default'

 * @return mixed new value, or false if the data doesn't exist, is not integer,

 *    or if there was an error fetching it.

 */

	public static function increment($key, $offset = 1, $config = 'default') {

		$settings = static::settings($config);

		if (empty($settings)) {

			return false;

		}

		if (!static::isInitialized($config)) {

			return false;

		}

		$key = static::$_engines[$config]->key($key);

		if (!$key || !is_int($offset) || $offset < 0) {

			return false;

		}

		$success = static::$_engines[$config]->increment($settings['prefix'] . $key, $offset);

		static::set(null, $config);

		return $success;

	}

/**

 * Decrement a number under the key and return decremented value.

 *

 * @param string $key Identifier for the data

 * @param int $offset How much to subtract

 * @param string $config Optional string configuration name. Defaults to 'default'

 * @return mixed new value, or false if the data doesn't exist, is not integer,

 *   or if there was an error fetching it

 */

	public static function decrement($key, $offset = 1, $config = 'default') {

		$settings = static::settings($config);

		if (empty($settings)) {

			return false;

		}

		if (!static::isInitialized($config)) {

			return false;

		}

		$key = static::$_engines[$config]->key($key);

		if (!$key || !is_int($offset) || $offset < 0) {

			return false;

		}

		$success = static::$_engines[$config]->decrement($settings['prefix'] . $key, $offset);

		static::set(null, $config);

		return $success;

	}

/**

 * Delete a key from the cache.

 *

 * ### Usage:

 *

 * Deleting from the active cache configuration.

 *

 * `Cache::delete('my_data');`

 *

 * Deleting from a specific cache configuration.

 *

 * `Cache::delete('my_data', 'long_term');`

 *

 * @param string $key Identifier for the data

 * @param string $config name of the configuration to use. Defaults to 'default'

 * @return bool True if the value was successfully deleted, false if it didn't exist or couldn't be removed

 */

	public static function delete($key, $config = 'default') {

		$settings = static::settings($config);

		if (empty($settings)) {

			return false;

		}

		if (!static::isInitialized($config)) {

			return false;

		}

		$key = static::$_engines[$config]->key($key);

		if (!$key) {

			return false;

		}

		$success = static::$_engines[$config]->delete($settings['prefix'] . $key);

		static::set(null, $config);

		return $success;

	}

/**

 * Delete all keys from the cache.

 *

 * @param bool $check if true will check expiration, otherwise delete all

 * @param string $config name of the configuration to use. Defaults to 'default'

 * @return bool True if the cache was successfully cleared, false otherwise

 */

	public static function clear($check = false, $config = 'default') {

		if (!static::isInitialized($config)) {

			return false;

		}

		$success = static::$_engines[$config]->clear($check);

		static::set(null, $config);

		return $success;

	}

/**

 * Delete all keys from the cache belonging to the same group.

 *

 * @param string $group name of the group to be cleared

 * @param string $config name of the configuration to use. Defaults to 'default'

 * @return bool True if the cache group was successfully cleared, false otherwise

 */

	public static function clearGroup($group, $config = 'default') {

		if (!static::isInitialized($config)) {

			return false;

		}

		$success = static::$_engines[$config]->clearGroup($group);

		static::set(null, $config);

		return $success;

	}

/**

 * Check if Cache has initialized a working config for the given name.

 *

 * @param string $config name of the configuration to use. Defaults to 'default'

 * @return bool Whether or not the config name has been initialized.

 */

	public static function isInitialized($config = 'default') {

		if (Configure::read('Cache.disable')) {

			return false;

		}

		return isset(static::$_engines[$config]);

	}

/**

 * Return the settings for the named cache engine.

 *

 * @param string $name Name of the configuration to get settings for. Defaults to 'default'

 * @return array list of settings for this engine

 * @see Cache::config()

 */

	public static function settings($name = 'default') {

		if (!empty(static::$_engines[$name])) {

			return static::$_engines[$name]->settings();

		}

		return array();

	}

/**

 * Retrieve group names to config mapping.

 *

 * ```

 *	Cache::config('daily', array(

 *		'duration' => '1 day', 'groups' => array('posts')

 *	));

 *	Cache::config('weekly', array(

 *		'duration' => '1 week', 'groups' => array('posts', 'archive')

 *	));

 *	$configs = Cache::groupConfigs('posts');

 * ```

 *

 * $config will equal to `array('posts' => array('daily', 'weekly'))`

 *

 * @param string $group group name or null to retrieve all group mappings

 * @return array map of group and all configuration that has the same group

 * @throws CacheException

 */

	public static function groupConfigs($group = null) {

		if ($group === null) {

			return static::$_groups;

		}

		if (isset(static::$_groups[$group])) {

			return array($group => static::$_groups[$group]);

		}

		throw new CacheException(__d('cake_dev', 'Invalid cache group %s', $group));

	}

/**

 * Provides the ability to easily do read-through caching.

 *

 * When called if the $key is not set in $config, the $callable function

 * will be invoked. The results will then be stored into the cache config

 * at key.

 *

 * Examples:

 *

 * Using a Closure to provide data, assume $this is a Model:

 *

 * ```

 * $model = $this;

 * $results = Cache::remember('all_articles', function() use ($model) {

 *      return $model->find('all');

 * });

 * ```

 *

 * @param string $key The cache key to read/store data at.

 * @param callable $callable The callable that provides data in the case when

 *   the cache key is empty. Can be any callable type supported by your PHP.

 * @param string $config The cache configuration to use for this operation.

 *   Defaults to default.

 * @return mixed The results of the callable or unserialized results.

 */

	public static function remember($key, $callable, $config = 'default') {

		$existing = static::read($key, $config);

		if ($existing !== false) {

			return $existing;

		}

		$results = call_user_func($callable);

		static::write($key, $results, $config);

		return $results;

	}

}