From f50573c33dea232fb160e4d71767706a2410ef65 Mon Sep 17 00:00:00 2001
From: Chad Horohoe <demon@users.mediawiki.org>
Date: Thu, 25 Jun 2009 00:40:12 +0000
Subject: [PATCH] * Move lock()/unlock() to DatabaseMysql, declare abstract *
 Introduce lockTables() and unlockTables(), define in DatabaseMysql * (bug
 19372) updateSearchIndex has MySQLisms.

---
 includes/db/Database.php          | 45 ++++++++++++++++---------------
 includes/db/DatabaseMysql.php     | 38 ++++++++++++++++++++++++++
 maintenance/updateSearchIndex.inc | 19 +++----------
 3 files changed, 65 insertions(+), 37 deletions(-)

diff --git a/includes/db/Database.php b/includes/db/Database.php
index 7d07816446..d6789c17cf 100644
--- a/includes/db/Database.php
+++ b/includes/db/Database.php
@@ -2176,7 +2176,7 @@ abstract class DatabaseBase {
 	}
 	
 	/**
-	 * Acquire a lock
+	 * Acquire a named lock
 	 * 
 	 * Abstracted from Filestore::lock() so child classes can implement for
 	 * their own needs.
@@ -2185,33 +2185,36 @@ abstract class DatabaseBase {
 	 * @param $method String: Name of method calling us
 	 * @return bool
 	 */
-	public function lock( $lockName, $method ) {
-		$lockName = $this->addQuotes( $lockName );
-		$result = $this->query( "SELECT GET_LOCK($lockName, 5) AS lockstatus", $method );
-		$row = $this->fetchObject( $result );
-		$this->freeResult( $result );
+	abstract public function lock( $lockName, $method, $timeout = 5 );
 
-		if( $row->lockstatus == 1 ) {
-			return true;
-		} else {
-			wfDebug( __METHOD__." failed to acquire lock\n" );
-			return false;
-		}
-	}
 	/**
 	 * Release a lock.
 	 * 
-	 * @todo fixme - Figure out a way to return a bool
-	 * based on successful lock release.
-	 * 
 	 * @param $lockName String: Name of lock to release
 	 * @param $method String: Name of method calling us
+	 *
+	 * FROM MYSQL DOCS: http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
+	 * @return Returns 1 if the lock was released, 0 if the lock was not established
+	 * by this thread (in which case the lock is not released), and NULL if the named 
+	 * lock did not exist
 	 */
-	public function unlock( $lockName, $method ) {
-		$lockName = $this->addQuotes( $lockName );
-		$result = $this->query( "SELECT RELEASE_LOCK($lockName)", $method );
-		$this->freeResult( $result );
-	}
+	abstract public function unlock( $lockName, $method );
+
+	/**
+	 * Lock specific tables
+	 *
+	 * @param $read Array of tables to lock for read access
+	 * @param $write Array of tables to lock for write access
+	 * @param $method String name of caller
+	 */
+	abstract public function lockTables( $read, $write, $method );
+	
+	/**
+	 * Unlock specific tables
+	 *
+	 * @param $method String the caller
+	 */
+	abstract public function unlockTables( $method );
 	
 	/**
 	 * Get search engine class. All subclasses of this
diff --git a/includes/db/DatabaseMysql.php b/includes/db/DatabaseMysql.php
index 6508eb234e..ecd3485c37 100644
--- a/includes/db/DatabaseMysql.php
+++ b/includes/db/DatabaseMysql.php
@@ -293,6 +293,44 @@ class DatabaseMysql extends DatabaseBase {
 		$this->query( "SET net_read_timeout=$timeout" );
 		$this->query( "SET net_write_timeout=$timeout" );
 	}
+
+	public function lock( $lockName, $method, $timeout = 5 ) {
+		$lockName = $this->addQuotes( $lockName );
+		$result = $this->query( "SELECT GET_LOCK($lockName, $timeout) AS lockstatus", $method );
+		$row = $this->fetchObject( $result );
+		$this->freeResult( $result );
+
+		if( $row->lockstatus == 1 ) {
+			return true;
+		} else {
+			wfDebug( __METHOD__." failed to acquire lock\n" );
+			return false;
+		}
+	}
+
+	public function unlock( $lockName, $method ) {
+		$lockName = $this->addQuotes( $lockName );
+		$result = $this->query( "SELECT RELEASE_LOCK($lockName) as lockstatus", $method );
+		$row = $this->fetchObject( $result );
+		return $row->lockstatus;
+	}
+
+	public function lockTables( $read, $write, $method ) {
+		$items = array();
+
+		foreach( $write as $table ) {
+			$items[] = $this->tableName( $table ) . ' LOW_PRIORITY WRITE';
+		}
+		foreach( $read as $table ) {
+			$items[] = $this->tableName( $table ) . ' READ';
+		}
+		$sql = "LOCK TABLES " . implode( ',', $items );
+		$db->query( $sql, $method );
+	}
+
+	public function unlockTables( $method ) {
+		$this->query( "UNLOCK TABLES", $method );
+	}
 }
 
 /**
diff --git a/maintenance/updateSearchIndex.inc b/maintenance/updateSearchIndex.inc
index 0cac4508cd..21e2df481b 100644
--- a/maintenance/updateSearchIndex.inc
+++ b/maintenance/updateSearchIndex.inc
@@ -75,7 +75,7 @@ function updateSearchIndex( $start, $end, $maxLockTime, $quiet ) {
 	# Unlock searchindex
 	if ( $maxLockTime ) {
 		output( "    --- Unlocking --" );
-		unlockSearchindex( $dbw );
+		$dbw->unlockTables( 'updateSearchIndex.inc ' . __METHOD__ );
 		output( "\n" );
 	}
 	output( "Done\n" );
@@ -84,27 +84,14 @@ function updateSearchIndex( $start, $end, $maxLockTime, $quiet ) {
 function lockSearchindex( &$db ) {
 	$write = array( 'searchindex' );
 	$read = array( 'page', 'revision', 'text', 'interwiki' );
-	$items = array();
-	
-	foreach( $write as $table ) {
-		$items[] = $db->tableName( $table ) . ' LOW_PRIORITY WRITE';
-	}
-	foreach( $read as $table ) {
-		$items[] = $db->tableName( $table ) . ' READ';
-	}
-	$sql = "LOCK TABLES " . implode( ',', $items );
-	$db->query( $sql, 'updateSearchIndex.inc ' . __METHOD__ );
-}
-
-function unlockSearchindex( &$db ) {
-	$db->query( "UNLOCK TABLES", 'updateSearchIndex.inc ' . __METHOD__ );
+	$db->lockTables( $read, $write, 'updateSearchIndex.inc ' . __METHOD__ );
 }
 
 # Unlock and lock again
 # Since the lock is low-priority, queued reads will be able to complete
 function relockSearchindex( &$db ) {
 	unlockSearchindex( $db );
-	lockSearchindex( $db );
+	$db->unlockTables( 'updateSearchIndex.inc ' . __METHOD__ );
 }
 
 function output( $text ) {
-- 
2.20.1