1 files changed, 108 insertions, 0 deletions
diff --git a/library/HTMLPurifier/DefinitionCache.php b/library/HTMLPurifier/DefinitionCache.php
new file mode 100644
index 000000000..c6e1e388c
--- /dev/null
+++ b/library/HTMLPurifier/DefinitionCache.php
@@ -0,0 +1,108 @@
+<?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