From e69ea9b6d25fed035f9ea671add2c883856fbe40 Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@users.mediawiki.org>
Date: Sun, 25 Dec 2005 11:04:40 +0000
Subject: [PATCH] * Added 'PageRenderingHash' hook for changing the parser
 cache hash key   from an extension that changes rendering based on
 nonstandard options.

---
 RELEASE-NOTES     |  2 ++
 docs/hooks.txt    |  5 +++++
 includes/User.php | 19 ++++++++++++++++++-
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index 6d6d0ca27e..29f4d0a3c9 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -352,6 +352,8 @@ fully support the editing toolbar, but was found to be too confusing.
 * (bug 4377) "[" is not valid in URLs
 * Don't delete thumbnails when refreshing exif metadata. This caused thumbs
   to vanish mysteriously from time to time for files that didn't have metadata.
+* Added 'PageRenderingHash' hook for changing the parser cache hash key
+  from an extension that changes rendering based on nonstandard options.
 
 
 === Caveats ===
diff --git a/docs/hooks.txt b/docs/hooks.txt
index 8ebddc85e7..85c479cc69 100644
--- a/docs/hooks.txt
+++ b/docs/hooks.txt
@@ -317,6 +317,11 @@ $typeText: array of strings
 'LogPageLogHeader': strings used by wfMsg as a header.
 $headerText: array of strings
 
+'PageRenderingHash': alter the parser cache option hash key
+  A parser extension which depends on user options should install
+  this hook and append its values to the key.
+$hash: reference to a hash key string which can be modified
+
 'TitleMoveComplete': after moving an article (title)
 $old: old title
 $nt: new title
diff --git a/includes/User.php b/includes/User.php
index 07a11b3344..c09d0bb053 100644
--- a/includes/User.php
+++ b/includes/User.php
@@ -1462,6 +1462,19 @@ class User {
 
 	}
 
+	/**
+	 * Generate a string which will be different for any combination of
+	 * user options which would produce different parser output.
+	 * This will be used as part of the hash key for the parser cache,
+	 * so users will the same options can share the same cached data
+	 * safely.
+	 *
+	 * Extensions which require it should install 'PageRenderingHash' hook,
+	 * which will give them a chance to modify this key based on their own
+	 * settings.
+	 *
+	 * @return string
+	 */
 	function getPageRenderingHash() {
 		global $wgContLang;
 		if( $this->mHash ){
@@ -1480,9 +1493,13 @@ class User {
 		// add in language specific options, if any
 		$extra = $wgContLang->getExtraHashOptions();
 		$confstr .= $extra;
+		
+		// Give a chance for extensions to modify the hash, if they have
+		// extra options or other effects on the parser cache.
+		wfRunHooks( 'PageRenderingHash', array( &$confstr ) );
 
 		$this->mHash = $confstr;
-		return $confstr ;
+		return $confstr;
 	}
 
 	function isAllowedToCreateAccount() {
-- 
2.20.1