File indexing completed on 2024-12-22 05:36:21

 <?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
 {
     /**
      * @type string
      */
     public $type;
 
     /**
      * @param string $type Type of definition objects this instance of the
      *      cache will handle.
      */
     public function __construct($type)
     {
         $this->type = $type;
     }
 
     /**
      * Generates a unique identifier for a particular configuration
      * @param HTMLPurifier_Config $config Instance of HTMLPurifier_Config
      * @return string
      */
     public function generateKey($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 string $key Key to test
      * @param HTMLPurifier_Config $config Instance of HTMLPurifier_Config to test against
      * @return bool
      */
     public function isOld($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 HTMLPurifier_Definition $def Definition object to check
      * @return bool true if good, false if not
      */
     public function checkDefType($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
      * @param HTMLPurifier_Definition $def
      * @param HTMLPurifier_Config $config
      */
     abstract public function add($def, $config);
 
     /**
      * Unconditionally saves a definition object to the cache
      * @param HTMLPurifier_Definition $def
      * @param HTMLPurifier_Config $config
      */
     abstract public function set($def, $config);
 
     /**
      * Replace an object in the cache
      * @param HTMLPurifier_Definition $def
      * @param HTMLPurifier_Config $config
      */
     abstract public function replace($def, $config);
 
     /**
      * Retrieves a definition object from the cache
      * @param HTMLPurifier_Config $config
      */
     abstract public function get($config);
 
     /**
      * Removes a definition object to the cache
      * @param HTMLPurifier_Config $config
      */
     abstract public function remove($config);
 
     /**
      * Clears all objects from cache
      * @param HTMLPurifier_Config $config
      */
     abstract public function flush($config);
 
     /**
      * Clears all expired (older version or revision) objects from cache
      * @note Be careful implementing this method as flush. Flush must
      *       not interfere with other Definition types, and cleanup()
      *       should not be repeatedly called by userland code.
      * @param HTMLPurifier_Config $config
      */
     abstract public function cleanup($config);
 }
 
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