[1.7.0] Factor out caching of definitions to DefinitionCache, hook in CSS, add a bunch of todos for this functionality. Attr namespace no longer affects HTMLDefinition.

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1093 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/DefinitionCache.php

@@ -0,0 +1,83 @@
+<?php
+
+require_once 'HTMLPurifier/DefinitionCache/Serializer.php';
+
+/**
+ * Abstract class representing Definition cache managers that implements
+ * useful common methods and is a factory.
+ * @note The configuration object is transformed into the key used by the cache
+ * @todo Implement flush()
+ * @todo Implement replace()
+ * @todo Get some sort of versioning variable so the library can easily
+ *       invalidate the cache with a new version
+ * @todo Make the test runner cache aware and allow the user to easily
+ *       flush the cache
+ * @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
+ * @todo Perform type checking on $def objects
+ */
+class HTMLPurifier_DefinitionCache
+{
+    
+    var $type;
+    
+    /**
+     * @param $name Type of definition objects this instance of the
+     *      cache will handle.
+     */
+    function HTMLPurifier_DefinitionCache($type) {
+        $this->type = $type;
+    }
+    
+    /**
+     * Generates a unique identifier for a particular configuration
+     * @param Instance of HTMLPurifier_Config
+     */
+    function generateKey($config) {
+        return md5(serialize($config->getBatch($this->type)));
+    }
+    
+    /**
+     * Factory method that creates a cache object based on configuration
+     * @param $name Name of definitions handled by cache
+     * @param $config Instance of HTMLPurifier_Config
+     */
+    function create($name, $config) {
+        // only one implementation as for right now, $config will
+        // be used to determine implementation
+        return new HTMLPurifier_DefinitionCache_Serializer($name);
+    }
+    
+    /**
+     * Adds a definition object to the cache
+     */
+    function add($def, $config) {
+        trigger_error('Cannot call abstract method', E_USER_ERROR);
+    }
+    
+    /**
+     * Unconditionally saves a definition object to the cache
+     */
+    function set($def, $config) {
+        trigger_error('Cannot call abstract method', E_USER_ERROR);
+    }
+    
+    /**
+     * Retrieves a definition object from the cache
+     */
+    function get($config) {
+        trigger_error('Cannot call abstract method', E_USER_ERROR);
+    }
+    
+    /**
+     * Removes a definition object to the cache
+     */
+    function remove($config) {
+        trigger_error('Cannot call abstract method', E_USER_ERROR);
+    }
+    
+}
+
+?>