<?php /** * Abstract class representing Definition cache managers that implements * useful common methods and is a factory. * @todo Create a separate maintenance file advanced users can use to * cache their custom HTMLDefinition, which can be loaded * via a configuration directive * @todo Implement memcached */ abstract class HTMLPurifier_DefinitionCache { public $type; /** * @param $name Type of definition objects this instance of the * cache will handle. */ public function __construct($type) { $this->type = $type; } /** * Generates a unique identifier for a particular configuration * @param Instance of HTMLPurifier_Config */ public function generateKey($config) { return $config->version . ',' . // possibly replace with function calls $config->getBatchSerial($this->type) . ',' . $config->get($this->type . '.DefinitionRev'); } /** * Tests whether or not a key is old with respect to the configuration's * version and revision number. * @param $key Key to test * @param $config Instance of HTMLPurifier_Config to test against */ public function isOld($key, $config) { if (substr_count($key, ',') < 2) return true; list($version, $hash, $revision) = explode(',', $key, 3); $compare = version_compare($version, $config->version); // version mismatch, is always old if ($compare != 0) return true; // versions match, ids match, check revision number if ( $hash == $config->getBatchSerial($this->type) && $revision < $config->get($this->type . '.DefinitionRev') ) return true; return false; } /** * Checks if a definition's type jives with the cache's type * @note Throws an error on failure * @param $def Definition object to check * @return Boolean true if good, false if not */ public function checkDefType($def) { if ($def->type !== $this->type) { trigger_error("Cannot use definition of type {$def->type} in cache for {$this->type}"); return false; } return true; } /** * Adds a definition object to the cache */ abstract public function add($def, $config); /** * Unconditionally saves a definition object to the cache */ abstract public function set($def, $config); /** * Replace an object in the cache */ abstract public function replace($def, $config); /** * Retrieves a definition object from the cache */ abstract public function get($config); /** * Removes a definition object to the cache */ abstract public function remove($config); /** * Clears all objects from cache */ abstract public function flush($config); /** * Clears all expired (older version or revision) objects from cache * @note Be carefuly implementing this method as flush. Flush must * not interfere with other Definition types, and cleanup() * should not be repeatedly called by userland code. */ abstract public function cleanup($config); } // vim: et sw=4 sts=4