From: Max Semenik <maxsem.wiki@gmail.com>
Date: Fri, 2 Jan 2015 08:47:26 +0000 (-0800)
Subject: Don't call localisation functions when initializing pageset
X-Git-Tag: 1.31.0-rc.0~12739^2
X-Git-Url: http://git.cyclocoop.org//%27%40script%40/%27?a=commitdiff_plain;h=fc505d4fa538c933cd1e2637454bbd2ccb8bcaae;p=lhc%2Fweb%2Fwiklou.git

Don't call localisation functions when initializing pageset

Language::commaList() gets called even though in 99% of cases it's not
description that's needed but other parameter information, resulting in
0.6% of overall cluster CPU time being wasted per
https://performance.wikimedia.org/xenon/svgs/daily/2015-01-02.svgz

Change-Id: Ic77e4a03d1bbd1aa5f86dc250d9f903d7eb25618
---

diff --git a/autoload.php b/autoload.php
index a1ac905569..f2b0554683 100644
--- a/autoload.php
+++ b/autoload.php
@@ -291,6 +291,7 @@ $wgAutoloadLocalClasses = array(
 	'DateFormatter' => __DIR__ . '/includes/parser/DateFormatter.php',
 	'DeadendPagesPage' => __DIR__ . '/includes/specials/SpecialDeadendpages.php',
 	'DeferrableUpdate' => __DIR__ . '/includes/deferred/DeferredUpdates.php',
+	'DeferredStringifier' => __DIR__ . '/includes/DeferredStringifier.php',
 	'DeferredUpdates' => __DIR__ . '/includes/deferred/DeferredUpdates.php',
 	'DeleteAction' => __DIR__ . '/includes/actions/DeleteAction.php',
 	'DeleteArchivedFiles' => __DIR__ . '/maintenance/deleteArchivedFiles.php',
diff --git a/includes/DeferredStringifier.php b/includes/DeferredStringifier.php
new file mode 100644
index 0000000000..bd32949833
--- /dev/null
+++ b/includes/DeferredStringifier.php
@@ -0,0 +1,55 @@
+<?php
+/**
+ * Class that defers a slow string generation until the string is actually needed.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * @since 1.25
+ */
+class DeferredStringifier {
+	/** @var callable Callback used for result string generation */
+	private $callback;
+	/** @var array */
+	private $params;
+	/** @var string */
+	private $result;
+
+	/**
+	 * @param callable $callback Callback that gets called by __toString
+	 * @param mixed $param,... Parameters to the callback
+	 */
+	public function __construct( $callback /*...*/ ) {
+		$this->params = func_get_args();
+		array_shift( $this->params );
+		$this->callback = $callback;
+	}
+
+	/**
+	 * Returns a string generated by callback
+	 *
+	 * @return string
+	 */
+	public function __toString() {
+		if ( $this->result === null ) {
+			$this->result = call_user_func_array( $this->callback, $this->params );
+		}
+		return $this->result;
+	}
+}
diff --git a/includes/api/ApiPageSet.php b/includes/api/ApiPageSet.php
index 1417ef7833..c7147cb39a 100644
--- a/includes/api/ApiPageSet.php
+++ b/includes/api/ApiPageSet.php
@@ -1326,7 +1326,13 @@ class ApiPageSet extends ApiBase {
 				ApiBase::PARAM_DFLT => false,
 				ApiBase::PARAM_HELP_MSG => array(
 					'api-pageset-param-converttitles',
-					$this->getLanguage()->commaList( LanguageConverter::$languagesWithVariants ),
+					new DeferredStringifier(
+						function ( IContextSource $context ) {
+							return $context->getLanguage()
+								->commaList( LanguageConverter::$languagesWithVariants );
+						},
+						$this
+					)
 				),
 			),
 		);