/cake/cake/libs/cache.php

<?php

/* SVN FILE: $Id: cache.php 7847 2008-11-08 02:54:07Z renan.saddam $ */

/**

 * Caching for CakePHP.

 *

 *

 * PHP versions 4 and 5

 *

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

 * Copyright 2005-2008, Cake Software Foundation, Inc. (http://www.cakefoundation.org)

 *

 * Licensed under The MIT License

 * Redistributions of files must retain the above copyright notice.

 *

 * @filesource

 * @copyright     Copyright 2005-2008, Cake Software Foundation, Inc. (http://www.cakefoundation.org)

 * @link          http://www.cakefoundation.org/projects/info/cakephp CakePHP(tm) Project

 * @package       cake

 * @subpackage    cake.cake.libs

 * @since         CakePHP(tm) v 1.2.0.4933

 * @version       $Revision: 7847 $

 * @modifiedby    $LastChangedBy: renan.saddam $

 * @lastmodified  $Date: 2008-11-07 20:54:07 -0600 (Fri, 07 Nov 2008) $

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

 */

/**

 * Caching for CakePHP.

 *

 * @package       cake

 * @subpackage    cake.cake.libs

 */

class Cache extends Object {

/**

 * Cache engine to use

 *

 * @var object

 * @access protected

 */

	var $_Engine = null;

/**

 * Cache configuration stack

 *

 * @var array

 * @access private

 */

	var $__config = array();

/**

 * Holds name of the current configuration being used

 *

 * @var array

 * @access private

 */

	var $__name = 'default';

/**

 * whether to reset the settings with the next call to self::set();

 *

 * @var array

 * @access private

 */

	var $__reset = false;

/**

 * Returns a singleton instance

 *

 * @return object

 * @access public

 * @static

 */

	function &getInstance() {

		static $instance = array();

		if (!$instance) {

			$instance[0] =& new Cache();

		}

		return $instance[0];

	}

/**

 * Tries to find and include a file for a cache engine and returns object instance

 *

 * @param $name	Name of the engine (without 'Engine')

 * @return mixed $engine object or null

 * @access private

 */

	function __loadEngine($name) {

		if (!class_exists($name . 'Engine')) {

			require LIBS . DS . 'cache' . DS . strtolower($name) . '.php';

		}

		return true;

	}

/**

 * Set the cache configuration to use

 *

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

 * @param string $name Name of the configuration

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

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

 * @access public

 * @static

 */

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

		$_this =& Cache::getInstance();

		if (is_array($name)) {

			$settings = $name;

		}



		if ($name === null || !is_string($name)) {

			$name = $_this->__name;

		}



		$current = array();

		if (isset($_this->__config[$name])) {

			$current = $_this->__config[$name];

		}



		if (!empty($settings)) {

			$_this->__name = null;

			$_this->__config[$name] = array_merge($current, $settings);

		}



		if (empty($_this->__config[$name]['engine'])) {

			return false;

		}



		$_this->__name = $name;

		$engine = $_this->__config[$name]['engine'];



		if (!$_this->isInitialized($engine)) {

			if ($_this->engine($engine, $_this->__config[$name]) === false) {

				return false;

			}

			$settings = $_this->__config[$name] = $_this->settings($engine);

		} else {

			$settings = $_this->__config[$name] = $_this->set($_this->__config[$name]);

		}

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

	}

/**

 * Set the cache engine to use or modify settings for one instance

 *

 * @param string $name Name of the engine (without 'Engine')

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

 * @return boolean True on success, false on failure

 * @access public

 * @static

 */

	function engine($name = 'File', $settings = array()) {

		if (!$name || Configure::read('Cache.disable')) {

			return false;

		}



		$cacheClass = $name . 'Engine';

		$_this =& Cache::getInstance();

		if (!isset($_this->_Engine[$name])) {

			if ($_this->__loadEngine($name) === false) {

				return false;

			}

			$_this->_Engine[$name] =& new $cacheClass();

		}



		if ($_this->_Engine[$name]->init($settings)) {

			if (time() % $_this->_Engine[$name]->settings['probability'] === 0) {

				$_this->_Engine[$name]->gc();

			}

			return true;

		}

		$_this->_Engine[$name] = null;

		return false;

	}

/**

 * Temporarily change settings to current config options. if no params are passed, resets settings if needed

 * Cache::write() will reset the configuration changes made

 *

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

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

 * @return array of settings

 * @access public

 * @static

 */

	function set($settings = array(), $value = null) {

		$_this =& Cache::getInstance();

		if (!isset($_this->__config[$_this->__name])) {

			return false;

		}



		$engine = $_this->__config[$_this->__name]['engine'];



		if (!empty($settings)) {

			$_this->__reset = true;

		}



		if ($_this->__reset === true) {

			if (empty($settings)) {

				$_this->__reset = false;

				$settings = $_this->__config[$_this->__name];

			} else {

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

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

				}

				$settings = array_merge($_this->__config[$_this->__name], $settings);

			}

			$_this->_Engine[$engine]->init($settings);

		}



		return $_this->settings($engine);

	}

/**

 * Garbage collection

 *

 * Permanently remove all expired and deleted data

 *

 * @return void

 * @access public

 * @static

 */

	function gc() {

		$_this =& Cache::getInstance();

		$config = $_this->config();

		extract($config);

		$_this->_Engine[$engine]->gc();

	}

/**

 * Write data for key into cache

 *

 * @param string $key Identifier for the data

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

 * @param mixed $config Optional - string configuration name, a duration for expiration,

 *				or array('config' => 'string configuration name', 'duration' => 'duration for expiration')

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

 * @access public

 * @static

 */

	function write($key, $value, $config = null) {

		$_this =& Cache::getInstance();

		$thisDuration = null;

		if (is_array($config)) {

			extract($config);

		} else if ($config && (is_numeric($config) || is_numeric($config[0]) || (isset($config[1]) && is_numeric($config[1])))) {

			$thisDuration = $config;

			$config = null;

		}



		if ($config && isset($_this->__config[$config])) {

			$settings = $_this->set($_this->__config[$config]);

		} else {

			$settings = $_this->settings();

		}



		if (empty($settings)) {

			return null;

		}

		extract($settings);



		if (!$_this->isInitialized($engine)) {

			return false;

		}



		if (!$key = $_this->_Engine[$engine]->key($key)) {

			return false;

		}



		if (is_resource($value)) {

			return false;

		}



		if ($thisDuration !== null) {

			if (!is_numeric($thisDuration)) {

				$thisDuration = strtotime($thisDuration) - time();

			}

			$duration = $thisDuration;

		}



		if ($duration < 1) {

			return false;

		}



		$success = $_this->_Engine[$engine]->write($settings['prefix'] . $key, $value, $duration);

		$settings = $_this->set();

		return $success;

	}

/**

 * Read a key from the cache

 *

 * @param string $key Identifier for the data

 * @param string $config name of the configuration to use

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

 * @access public

 * @static

 */

	function read($key, $config = null) {

		$_this =& Cache::getInstance();



		if (isset($_this->__config[$config])) {

			$settings = $_this->set($_this->__config[$config]);

		} else {

			$settings = $_this->settings();

		}



		if (empty($settings)) {

			return null;

		}

		extract($settings);



		if (!$_this->isInitialized($engine)) {

			return false;

		}

		if (!$key = $_this->_Engine[$engine]->key($key)) {

			return false;

		}

		$success = $_this->_Engine[$engine]->read($settings['prefix'] . $key);



		if ($config !== null && $config !== $_this->__name) {

			$settings = $_this->set();

		}

		return $success;

	}

/**

 * Delete a key from the cache

 *

 * @param string $key Identifier for the data

 * @param string $config name of the configuration to use

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

 * @access public

 * @static

 */

	function delete($key, $config = null) {

		$_this =& Cache::getInstance();

		if (isset($_this->__config[$config])) {

			$settings = $_this->set($_this->__config[$config]);

		} else {

			$settings = $_this->settings();

		}



		if (empty($settings)) {

			return null;

		}

		extract($settings);



		if (!$_this->isInitialized($engine)) {

			return false;

		}



		if (!$key = $_this->_Engine[$engine]->key($key)) {

			return false;

		}



		$success = $_this->_Engine[$engine]->delete($settings['prefix'] . $key);

		$settings = $_this->set();

		return $success;

	}

/**

 * Delete all keys from the cache

 *

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

 * @param string $config name of the configuration to use

 * @return boolean True if the cache was succesfully cleared, false otherwise

 * @access public

 * @static

 */

	function clear($check = false, $config = null) {

		$_this =& Cache::getInstance();

		if (isset($_this->__config[$config])) {

			$settings = $_this->set($_this->__config[$config]);

		} else {

			$settings = $_this->settings();

		}



		if (empty($settings)) {

			return null;

		}

		extract($settings);



		if (isset($engine) && !$_this->isInitialized($engine)) {

			return false;

		}

		$success = $_this->_Engine[$engine]->clear($check);

		$settings = $_this->set();

		return $success;

	}

/**

 * Check if Cache has initialized a working storage engine

 *

 * @param string $engine Name of the engine

 * @param string $config Name of the configuration setting

 * @return bool

 * @access public

 * @static

 */

	function isInitialized($engine = null) {

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

			return false;

		}

		$_this =& Cache::getInstance();

		if (!$engine && isset($_this->__config[$_this->__name]['engine'])) {

			$engine = $_this->__config[$_this->__name]['engine'];

		}

		return isset($_this->_Engine[$engine]);

	}



/**

 * Return the settings for current cache engine

 *

 * @param string $engine Name of the engine

 * @return array list of settings for this engine

 * @access public

 * @static

 */

	function settings($engine = null) {

		$_this =& Cache::getInstance();

		if (!$engine && isset($_this->__config[$_this->__name]['engine'])) {

			$engine = $_this->__config[$_this->__name]['engine'];

		}



		if (isset($_this->_Engine[$engine]) && !is_null($_this->_Engine[$engine])) {

			return $_this->_Engine[$engine]->settings();

		}

		return array();

	}

}

/**

 * Storage engine for CakePHP caching

 *

 * @package       cake

 * @subpackage    cake.cake.libs

 */

class CacheEngine extends Object {

/**

 * settings of current engine instance

 *

 * @var int

 * @access public

 */

	var $settings = array();

/**

 * Iitialize the cache engine

 *

 * Called automatically by the cache frontend

 *

 * @param array $params Associative array of parameters for the engine

 * @return boolean True if the engine has been succesfully initialized, false if not

 * @access public

 */

	function init($settings = array()) {

		$this->settings = array_merge(array('prefix' => 'cake_', 'duration'=> 3600, 'probability'=> 100), $this->settings, $settings);

		if (!is_numeric($this->settings['duration'])) {

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

		}

		return true;

	}

/**

 * Garbage collection

 *

 * Permanently remove all expired and deleted data

 *

 * @access public

 */

	function gc() {

	}

/**

 * Write value for a key into cache

 *

 * @param string $key Identifier for the data

 * @param mixed $value Data to be cached

 * @param mixed $duration How long to cache the data, in seconds

 * @return boolean True if the data was succesfully cached, false on failure

 * @access public

 */

	function write($key, &$value, $duration) {

		trigger_error(sprintf(__('Method write() not implemented in %s', true), get_class($this)), E_USER_ERROR);

	}

/**

 * Read a key from the cache

 *

 * @param string $key Identifier for the data

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

 * @access public

 */

	function read($key) {

		trigger_error(sprintf(__('Method read() not implemented in %s', true), get_class($this)), E_USER_ERROR);

	}

/**

 * Delete a key from the cache

 *

 * @param string $key Identifier for the data

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

 * @access public

 */

	function delete($key) {

	}

/**

 * Delete all keys from the cache

 *

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

 * @return boolean True if the cache was succesfully cleared, false otherwise

 * @access public

 */

	function clear($check) {

	}

/**

 * Cache Engine settings

 *

 * @return array settings

 * @access public

 */

	function settings() {

		return $this->settings;

	}

/**

 * generates a safe key

 *

 * @param string $key the key passed over

 * @return mixed string $key or false

 * @access public

 */

	function key($key) {

		if (empty($key)) {

			return false;

		}

		$key = Inflector::underscore(str_replace(array(DS, '/', '.'), '_', strval($key)));

		return $key;

	}

}

?>