From 704583440ed27e1e0b7f463112233816cdade8a1 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Tue, 14 Jul 2015 12:11:32 -0700
Subject: [PATCH] Added DBAccessObjectUtils class to avoid duplication

* WikiPage is the first caller to use this instead of DIY
* This can be used elsewhere to keep callers uniform

Change-Id: Ia6371eaa185d70d1431271b2c6c955523cd424e8
---
 autoload.php                         |  1 +
 includes/dao/DBAccessObjectUtils.php | 59 ++++++++++++++++++++++++++++
 includes/page/WikiPage.php           | 14 +++----
 3 files changed, 67 insertions(+), 7 deletions(-)
 create mode 100644 includes/dao/DBAccessObjectUtils.php

diff --git a/autoload.php b/autoload.php
index 6444e3efa8..2a096f460b 100644
--- a/autoload.php
+++ b/autoload.php
@@ -279,6 +279,7 @@ $wgAutoloadLocalClasses = array(
 	'CurlHttpRequest' => __DIR__ . '/includes/HttpFunctions.php',
 	'DBAccessBase' => __DIR__ . '/includes/dao/DBAccessBase.php',
 	'DBAccessError' => __DIR__ . '/includes/db/LBFactory.php',
+	'DBAccessObjectUtils' => __DIR__ . '/includes/dao/DBAccessObjectUtils.php',
 	'DBConnRef' => __DIR__ . '/includes/db/DBConnRef.php',
 	'DBConnectionError' => __DIR__ . '/includes/db/DatabaseError.php',
 	'DBError' => __DIR__ . '/includes/db/DatabaseError.php',
diff --git a/includes/dao/DBAccessObjectUtils.php b/includes/dao/DBAccessObjectUtils.php
new file mode 100644
index 0000000000..58f991fc10
--- /dev/null
+++ b/includes/dao/DBAccessObjectUtils.php
@@ -0,0 +1,59 @@
+<?php
+/**
+ * This file contains database access object related constants.
+ *
+ * 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 Database
+ */
+
+/**
+ * Helper class for DAO classes
+ *
+ * @since 1.26
+ */
+class DBAccessObjectUtils {
+	/**
+	 * @param integer $bitfield
+	 * @param integer $flags IDBAccessObject::READ_* constant
+	 * @return bool Bitfield has flag $flag set
+	 */
+	public static function hasFlags( $bitfield, $flags ) {
+		return ( $bitfield & $flags ) == $flags;
+	}
+
+	/**
+	 * Get an appropriate DB index and options for a query
+	 *
+	 * @param integer $bitfield
+	 * @return array (DB_MASTER/DB_SLAVE, SELECT options array)
+	 */
+	public static function getDBOptions( $bitfield ) {
+		$index = self::hasFlags( $bitfield, IDBAccessObject::READ_LATEST )
+			? DB_MASTER
+			: DB_SLAVE;
+
+		$options = array();
+		if ( self::hasFlags( $bitfield, IDBAccessObject::READ_EXCLUSIVE ) ) {
+			$options[] = 'FOR UPDATE';
+		} elseif ( self::hasFlags( $bitfield, IDBAccessObject::READ_LOCKING ) ) {
+			$options[] = 'LOCK IN SHARE MODE';
+		}
+
+		return array( $index, $options );
+	}
+}
\ No newline at end of file
diff --git a/includes/page/WikiPage.php b/includes/page/WikiPage.php
index f7f25289b5..fe0ca0d311 100644
--- a/includes/page/WikiPage.php
+++ b/includes/page/WikiPage.php
@@ -361,18 +361,18 @@ class WikiPage implements Page, IDBAccessObject {
 			return;
 		}
 
-		if ( $from === self::READ_LOCKING ) {
-			$data = $this->pageDataFromTitle( wfGetDB( DB_MASTER ), $this->mTitle, array( 'FOR UPDATE' ) );
-		} elseif ( $from === self::READ_LATEST ) {
-			$data = $this->pageDataFromTitle( wfGetDB( DB_MASTER ), $this->mTitle );
-		} elseif ( $from === self::READ_NORMAL ) {
-			$data = $this->pageDataFromTitle( wfGetDB( DB_SLAVE ), $this->mTitle );
+		if ( is_int( $from ) ) {
+			list( $index, $opts ) = DBAccessObjectUtils::getDBOptions( $from );
+			$data = $this->pageDataFromTitle( wfGetDB( $index ), $this->mTitle, $opts );
+
 			if ( !$data
+				&& $index == DB_SLAVE
 				&& wfGetLB()->getServerCount() > 1
 				&& wfGetLB()->hasOrMadeRecentMasterChanges()
 			) {
 				$from = self::READ_LATEST;
-				$data = $this->pageDataFromTitle( wfGetDB( DB_MASTER ), $this->mTitle );
+				list( $index, $opts ) = DBAccessObjectUtils::getDBOptions( $from );
+				$data = $this->pageDataFromTitle( wfGetDB( $index ), $this->mTitle, $opts );
 			}
 		} else {
 			// No idea from where the caller got this data, assume slave database.
-- 
2.20.1