From 3817818aca9733684a9dd0e75d7c3168ddf3f033 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Wed, 4 Feb 2015 18:22:08 -0800
Subject: [PATCH] Add a ReplicatedBagOStuff class

Bug: T88634
Change-Id: I1f7cccd6ac376055ff2b84641ff38a85571c65b0
---
 autoload.php                                 |   1 +
 includes/objectcache/ReplicatedBagOStuff.php | 126 +++++++++++++++++++
 2 files changed, 127 insertions(+)
 create mode 100644 includes/objectcache/ReplicatedBagOStuff.php

diff --git a/autoload.php b/autoload.php
index a5560f23a0..705f5bda4e 100644
--- a/autoload.php
+++ b/autoload.php
@@ -964,6 +964,7 @@ $wgAutoloadLocalClasses = array(
 	'RenderAction' => __DIR__ . '/includes/actions/RenderAction.php',
 	'ReplacementArray' => __DIR__ . '/includes/libs/ReplacementArray.php',
 	'Replacer' => __DIR__ . '/includes/libs/replacers/Replacer.php',
+	'ReplicatedBagOStuff' => __DIR__ . '/includes/objectcache/ReplicatedBagOStuff.php',
 	'RepoGroup' => __DIR__ . '/includes/filerepo/RepoGroup.php',
 	'RequestContext' => __DIR__ . '/includes/context/RequestContext.php',
 	'ResetUserTokens' => __DIR__ . '/maintenance/resetUserTokens.php',
diff --git a/includes/objectcache/ReplicatedBagOStuff.php b/includes/objectcache/ReplicatedBagOStuff.php
new file mode 100644
index 0000000000..8097308f69
--- /dev/null
+++ b/includes/objectcache/ReplicatedBagOStuff.php
@@ -0,0 +1,126 @@
+<?php
+/**
+ * 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
+ * @ingroup Cache
+ * @author Aaron Schulz
+ */
+
+/**
+ * A cache class that directs writes to one set of servers and reads to
+ * another. This assumes that the servers used for reads are setup to slave
+ * those that writes go to. This can easily be used with redis for example.
+ *
+ * In the WAN scenario (e.g. multi-datacenter case), this is useful when
+ * writes are rare or usually takes place on the primary datacenter.
+ *
+ * @ingroup Cache
+ * @since 1.25
+ */
+class ReplicatedBagOStuff extends BagOStuff {
+	/** @var BagOStuff */
+	protected $mCache;
+	/** @var BagOStuff */
+	protected $sCache;
+
+	/**
+	 * Constructor. Parameters are:
+	 *   - masterCache : Cache parameter structures, in the style required by $wgObjectCaches.
+	 *                   See the documentation of $wgObjectCaches for more detail.
+	 *   - slaveCache  : Cache parameter structures, in the style required by $wgObjectCaches.
+	 *                   See the documentation of $wgObjectCaches for more detail.
+	 *
+	 * @param array $params
+	 * @throws MWException
+	 */
+	public function __construct( $params ) {
+		parent::__construct( $params );
+
+		if ( !isset( $params['masterCache'] ) ) {
+			throw new MWException( __METHOD__ . ': the "masterCache" parameter is required' );
+		} elseif ( !isset( $params['slaveCache'] ) ) {
+			throw new MWException( __METHOD__ . ': the "slaveCache" parameter is required' );
+		}
+
+		$this->mCache = ( $params['masterCache'] instanceof BagOStuff )
+			? $params['masterCache']
+			: ObjectCache::newFromParams( $params['masterCache'] );
+		$this->sCache = ( $params['slaveCache'] instanceof BagOStuff )
+			? $params['slaveCache']
+			: ObjectCache::newFromParams( $params['slaveCache'] );
+	}
+
+	public function setDebug( $debug ) {
+		$this->mCache->setDebug( $debug );
+		$this->sCache->setDebug( $debug );
+	}
+
+	public function get( $key, &$casToken = null ) {
+		return $this->sCache->get( $key, $casToken );
+	}
+
+	public function getMulti( $keys ) {
+		return $this->sCache->getMulti( $keys );
+	}
+
+	public function set( $key, $value, $exptime = 0 ) {
+		return $this->mCache->set( $key, $value, $exptime );
+	}
+
+	public function delete( $key ) {
+		return $this->mCache->delete( $key );
+	}
+
+	public function add( $key, $value, $exptime = 0 ) {
+		return $this->mCache->add( $key, $value, $exptime );
+	}
+
+	public function incr( $key, $value = 1 ) {
+		return $this->mCache->incr( $key, $value );
+	}
+
+	public function decr( $key ) {
+		return $this->mCache->decr( $key );
+	}
+
+	public function lock( $key, $timeout = 6, $expiry = 6 ) {
+		return $this->mCache->lock( $key, $timeout, $expiry );
+	}
+
+	public function unlock( $key ) {
+		return $this->mCache->unlock( $key );
+	}
+
+	public function merge( $key, $callback, $exptime = 0, $attempts = 10 ) {
+		return $this->mCache->merge( $key, $callback, $exptime, $attempts );
+	}
+
+	public function getLastError() {
+		return ( $this->mCache->getLastError() != self::ERR_NONE )
+			? $this->mCache->getLastError()
+			: $this->sCache->getLastError();
+	}
+
+	public function clearLastError() {
+		$this->mCache->clearLastError();
+		$this->sCache->clearLastError();
+	}
+
+	protected function cas( $casToken, $key, $value, $exptime = 0 ) {
+		$this->mCache->cas( $casToken, $key, $value, $exptime );
+	}
+}
-- 
2.20.1