Add hook for custom difference engine (WikEdDiff)

The new Extension:WikEdDiff is a custom inline difference engine.
There is currently no hook to integrate custom difference engines.
This patch adds a new hook called 'GetDifferenceEngine' in
/includes/content/ContentHandler.php in function
'createDifferenceEngine()'.

Passed variables:
$context: IContextSource context to be used for diff
$old: Revision ID to show and diff with
$new: Either a revision ID or one of the strings 'cur', 'prev' or 'next'
$refreshCache: If set, refreshes the diff cache
$unhide: If set, allow viewing deleted revs
&$differenceEngine: output parameter, difference engine object to be used
for diff

If the hook handler returns false, a valid difference engine object is
returned in the passed-by-reference variable $differenceEngine.
If the handler returns true, the default engine is used as fallback.

The specified diff engine class will typically be an extension of the
class DifferenceEngine (includes/diff/DifferenceEngine.php) with
modifications, e.g. of function generateTextDiffBody() and
__construct() (without deprecated parameter $rcid).

Also fixes a missing declaration in DifferenceEngine that is required for
extending this class.

Bug: 71916
Change-Id: I9da63c1ceb339bfeba7beddc712be51977b95f65

diff --git a/docs/hooks.txt b/docs/hooks.txt
index 7ec6ff5..5bf9ef2 100644 (file)
--- a/docs/hooks.txt
+++ b/docs/hooks.txt
@@ -989,6 +989,15 @@ $title: the diff page title (nullable)
 $old: the ?old= param value from the url
 $new: the ?new= param value from the url
 
+'GetDifferenceEngine': Called when getting a new difference engine interface object
+Return false for valid object in $differenceEngine or true for the default difference engine
+$context: IContextSource context to be used for diff
+$old: Revision ID to show and diff with
+$new: Either a revision ID or one of the strings 'cur', 'prev' or 'next'
+$refreshCache: If set, refreshes the diff cache
+$unhide: If set, allow viewing deleted revs
+&$differenceEngine: output parameter, difference engine object to be used for diff
+
 'DiffRevisionTools': Override or extend the revision tools available from the
 diff view, i.e. undo, etc.
 $newRev: Revision object of the "new" revision

diff --git a/includes/content/ContentHandler.php b/includes/content/ContentHandler.php
index ac41722..bcecefa 100644 (file)
--- a/includes/content/ContentHandler.php
+++ b/includes/content/ContentHandler.php
@@ -626,8 +626,15 @@ abstract class ContentHandler {
        public function createDifferenceEngine( IContextSource $context, $old = 0, $new = 0,
                $rcid = 0, //FIXME: Deprecated, no longer used
                $refreshCache = false, $unhide = false ) {
-               $diffEngineClass = $this->getDiffEngineClass();
 
+               // hook: get difference engine
+               $differenceEngine = null;
+               if ( !wfRunHooks( 'GetDifferenceEngine',
+                       array( $context, $old, $new, $refreshCache, $unhide, &$differenceEngine )
+               ) ) {
+                       return $differenceEngine;
+               }
+               $diffEngineClass = $this->getDiffEngineClass();
                return new $diffEngineClass( $context, $old, $new, $rcid, $refreshCache, $unhide );
        }
 

diff --git a/includes/diff/DifferenceEngine.php b/includes/diff/DifferenceEngine.php
index dd5f3c7..ba9878f 100644 (file)
--- a/includes/diff/DifferenceEngine.php
+++ b/includes/diff/DifferenceEngine.php
@@ -94,6 +94,10 @@ class DifferenceEngine extends ContextSource {
 
        /** @var bool Show rev_deleted content if allowed */
        protected $unhide = false;
+
+       /** @var bool Refresh the diff cache */
+       protected $mRefreshCache = false;
+
        /**#@-*/
 
        /**