From 63601400e476c6cf43d985f3e7b9864681695ed4 Mon Sep 17 00:00:00 2001
From: Pierre Schmitz <pierre@archlinux.de>
Date: Fri, 18 Jan 2013 16:46:04 +0100
Subject: Update to MediaWiki 1.20.2

this update includes:
* adjusted Arch Linux skin
* updated FluxBBAuthPlugin
* patch for https://bugzilla.wikimedia.org/show_bug.cgi?id=44024
---
 includes/dao/IDBAccessObject.php | 55 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 includes/dao/IDBAccessObject.php

(limited to 'includes/dao')

diff --git a/includes/dao/IDBAccessObject.php b/includes/dao/IDBAccessObject.php
new file mode 100644
index 00000000..e30522a5
--- /dev/null
+++ b/includes/dao/IDBAccessObject.php
@@ -0,0 +1,55 @@
+<?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
+ */
+
+/**
+ * Interface for database access objects.
+ *
+ * Classes using this support a set of constants in a bitfield argument to their data loading
+ * functions. In general, objects should assume READ_NORMAL if no flags are explicitly given,
+ * though certain objects may assume READ_LATEST for common use case or legacy reasons.
+ *
+ * There are three types of reads:
+ *   - READ_NORMAL  : Potentially cached read of data (e.g. from a slave or stale replica)
+ *   - READ_LATEST  : Up-to-date read as of transaction start (e.g. from master or a quorum read)
+ *   - READ_LOCKING : Up-to-date read as of now, that locks the records for the transaction
+ *
+ * Callers should use READ_NORMAL (or pass in no flags) unless the read determines a write.
+ * In theory, such cases may require READ_LOCKING, though to avoid contention, READ_LATEST is
+ * often good enough. If UPDATE race condition checks are required on a row and expensive code
+ * must run after the row is fetched to determine the UPDATE, it may help to do something like:
+ *   - a) Read the current row
+ *   - b) Determine the new row (expensive, so we don't want to hold locks now)
+ *   - c) Re-read the current row with READ_LOCKING; if it changed then bail out
+ *   - d) otherwise, do the updates
+ */
+interface IDBAccessObject {
+	// Constants for object loading bitfield flags (higher => higher QoS)
+	const READ_LATEST  = 1; // read from the master
+	const READ_LOCKING = 3; // READ_LATEST and "FOR UPDATE"
+
+	// Convenience constant for callers to explicitly request slave data
+	const READ_NORMAL = 0; // read from the slave
+
+	// Convenience constant for tracking how data was loaded (higher => higher QoS)
+	const READ_NONE = -1; // not loaded yet (or the object was cleared)
+}
-- 
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