LinkCache singleton can now be altered

This patch adds the ability to destroy the LinkCache singleton or to
replace the instance with a different object.  Note the $instance static
variable is now at the class level instead of at the method level.

Change-Id: Ib110ad061868834a52a6bac651976b3ffab4a6ce

diff --git a/RELEASE-NOTES-1.22 b/RELEASE-NOTES-1.22
index c101bc9..68624eb 100644 (file)
--- a/RELEASE-NOTES-1.22
+++ b/RELEASE-NOTES-1.22
@@ -97,6 +97,8 @@ production.
   http://www.oracle-base.com/articles/11g/database-resident-connection-pool-11gr1.php
 * Add a new parameter $patrolFooterShown to hook ArticleViewFooter so the hook
   handlers can take further action based on the status of the patrol footer
+* LinkCache singleton can now be altered or cleared, letting one to specify
+  another instance that does not rely on a database backend.
 
 === Bug fixes in 1.22 ===
 * Disable Special:PasswordReset when $wgEnableEmail is false. Previously one

diff --git a/includes/cache/LinkCache.php b/includes/cache/LinkCache.php
index 31982e0..6ac7e7a 100644 (file)
--- a/includes/cache/LinkCache.php
+++ b/includes/cache/LinkCache.php
@@ -37,16 +37,41 @@ class LinkCache {
        private $mForUpdate = false;
 
        /**
-        * Get an instance of this class
+        * @var LinkCache
+        */
+       protected static $instance;
+
+       /**
+        * Get an instance of this class.
         *
         * @return LinkCache
         */
        static function &singleton() {
-               static $instance;
-               if ( !isset( $instance ) ) {
-                       $instance = new LinkCache;
+               if ( self::$instance ) {
+                       return self::$instance;
                }
-               return $instance;
+               self::$instance = new LinkCache;
+               return self::$instance;
+       }
+
+       /**
+        * Destroy the singleton instance, a new one will be created next time
+        * singleton() is called.
+        * @since 1.22
+        */
+       static function destroySingleton() {
+               self::$instance = null;
+       }
+
+       /**
+        * Set the singleton instance to a given object.
+        * Since we do not have an interface for LinkCache, you have to be sure the
+        * given object implements all the LinkCache public methods.
+        * @param LinkCache $instance
+        * @since 1.22
+        */
+       static function setSingleton( LinkCache $instance ) {
+               self::$instance = $instance;
        }
 
        /**