From 04736acd442c3d8337ee08b8f1b41e5683860347 Mon Sep 17 00:00:00 2001
From: Jack Phoenix <jack@countervandalism.net>
Date: Thu, 17 Nov 2016 04:14:26 +0200
Subject: [PATCH] A few more hooks in DifferenceEngine

For mucking with the class member variable mNewContent and optionally
allowing the suppression of the "missing revision" message when revision
data is not found for a requested revision.

Originally implemented as the "GetUserMessagesDiffCurrent" hook (yes,
these three separate hooks in three separate places were essentially the
same) by Wikia for their SiteWideMessages extension.

Change-Id: Ie0c175af2af418d4ed3de28c94df918115312da3
---
 docs/hooks.txt                     | 18 ++++++++++++++++++
 includes/diff/DifferenceEngine.php |  8 ++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/docs/hooks.txt b/docs/hooks.txt
index 7efd5d2cad..1ecc1f82d8 100644
--- a/docs/hooks.txt
+++ b/docs/hooks.txt
@@ -1190,6 +1190,18 @@ $page: SpecialPage object for DeletedContributions
 $row: the DB row for this line
 &$classes: the classes to add to the surrounding <li>
 
+'DifferenceEngineAfterLoadNewText': called in DifferenceEngine::loadNewText()
+after the new revision's content has been loaded into the class member variable
+$differenceEngine->mNewContent but before returning true from this function.
+$differenceEngine: DifferenceEngine object
+
+'DifferenceEngineLoadTextAfterNewContentIsLoaded': called in
+DifferenceEngine::loadText() after the new revision's content has been loaded
+into the class member variable $differenceEngine->mNewContent but before
+checking if the variable's value is null.
+This hook can be used to inject content into said class member variable.
+$differenceEngine: DifferenceEngine object
+
 'DifferenceEngineMarkPatrolledLink': Allows extensions to change the "mark as patrolled" link
 which is shown both on the diff header as well as on the bottom of a page, usually
 wrapped in a span element which has class="patrollink".
@@ -1268,6 +1280,12 @@ $differenceEngine: DifferenceEngine object
 object into the diff view
 $out: OutputPage object
 
+'DifferenceEngineShowDiffPageMaybeShowMissingRevision': called in
+DifferenceEngine::showDiffPage() when revision data cannot be loaded.
+Return false in order to prevent displaying the missing revision message
+(i.e. to prevent DifferenceEngine::showMissingRevision() from being called).
+$differenceEngine: DifferenceEngine object
+
 '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/diff/DifferenceEngine.php b/includes/diff/DifferenceEngine.php
index bd65fb42dc..5e40f43b5f 100644
--- a/includes/diff/DifferenceEngine.php
+++ b/includes/diff/DifferenceEngine.php
@@ -247,8 +247,9 @@ class DifferenceEngine extends ContextSource {
 		Hooks::run( 'DifferenceEngineShowDiffPage', [ $out ] );
 
 		if ( !$this->loadRevisionData() ) {
-			$this->showMissingRevision();
-
+			if ( Hooks::run( 'DifferenceEngineShowDiffPageMaybeShowMissingRevision', [ $this ] ) ) {
+				$this->showMissingRevision();
+			}
 			return;
 		}
 
@@ -1369,6 +1370,7 @@ class DifferenceEngine extends ContextSource {
 
 		if ( $this->mNewRev ) {
 			$this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
+			Hooks::run( 'DifferenceEngineLoadTextAfterNewContentIsLoaded', [ $this ] );
 			if ( $this->mNewContent === null ) {
 				return false;
 			}
@@ -1395,6 +1397,8 @@ class DifferenceEngine extends ContextSource {
 
 		$this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
 
+		Hooks::run( 'DifferenceEngineAfterLoadNewText', [ $this ] );
+
 		return true;
 	}
 
-- 
2.20.1