From 38828a93a17e63abb85442c90f04f6cac20034ec Mon Sep 17 00:00:00 2001
From: daniel <daniel.kinzler@wikimedia.de>
Date: Thu, 14 Jun 2012 12:33:16 +0200
Subject: [PATCH] Use class-static var for storing ContentHandler singletons.

$wgContentHandlers will be used for configuration only, and
is no longer changed during operation.

It's no longer possible to supply instances directly in $wgContentHandlers,
it only takes class names now.

Change-Id: Ifafb08d8638eff0d6965cd92fadbd9071c74de37
---
 includes/ContentHandler.php | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/includes/ContentHandler.php b/includes/ContentHandler.php
index 486de365c6..63fa47df48 100644
--- a/includes/ContentHandler.php
+++ b/includes/ContentHandler.php
@@ -247,6 +247,11 @@ abstract class ContentHandler {
 		return ContentHandler::getForModelID( $modelId );
 	}
 
+	/**
+	 * @var Array A Cache of ContentHandler instances by model id
+	 */
+	static $handlers;
+
 	/**
 	 * Returns the ContentHandler singleton for the given model ID. Use the
 	 * CONTENT_MODEL_XXX constants to identify the desired content model.
@@ -276,25 +281,33 @@ abstract class ContentHandler {
 	public static function getForModelID( $modelId ) {
 		global $wgContentHandlers;
 
+		if ( isset( ContentHandler::$handlers[$modelId] ) ) {
+			return ContentHandler::$handlers[$modelId];
+		}
+
 		if ( empty( $wgContentHandlers[$modelId] ) ) {
 			$handler = null;
 
 			wfRunHooks( 'ContentHandlerForModelID', array( $modelId, &$handler ) );
 
-			if ( $handler ) { // NOTE: may be a string or an object, either is fine!
-				$wgContentHandlers[$modelId] = $handler;
-			} else {
-				throw new MWException( "No handler for model #$modelId registered " .
-					"in \$wgContentHandlers" );
+			if ( $handler === null ) {
+				throw new MWException( "No handler for model #$modelId registered in \$wgContentHandlers" );
 			}
-		}
 
-		if ( is_string( $wgContentHandlers[$modelId] ) ) {
+			if ( !( $handler instanceof ContentHandler ) ) {
+				throw new MWException( "ContentHandlerForModelID must supply a ContentHandler instance" );
+			}
+		} else {
 			$class = $wgContentHandlers[$modelId];
-			$wgContentHandlers[$modelId] = new $class( $modelId );
+			$handler = new $class( $modelId );
+
+			if ( !( $handler instanceof ContentHandler ) ) {
+				throw new MWException( "$class from \$wgContentHandlers is not compatible with ContentHandler" );
+			}
 		}
 
-		return $wgContentHandlers[$modelId];
+		ContentHandler::$handlers[$modelId] = $handler;
+		return ContentHandler::$handlers[$modelId];
 	}
 
 	/**
-- 
2.20.1