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

1 files changed, 319 insertions, 0 deletions

diff --git a/includes/filebackend/lockmanager/MemcLockManager.php b/includes/filebackend/lockmanager/MemcLockManager.php
new file mode 100644
index 00000000..57c0463d
--- /dev/null
+++ b/includes/filebackend/lockmanager/MemcLockManager.php
@@ -0,0 +1,319 @@
+<?php
+/**
+ * Version of LockManager based on using memcached servers.
+ *
+ * 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 LockManager
+ */
+
+/**
+ * Manage locks using memcached servers.
+ *
+ * Version of LockManager based on using memcached servers.
+ * This is meant for multi-wiki systems that may share files.
+ * All locks are non-blocking, which avoids deadlocks.
+ *
+ * All lock requests for a resource, identified by a hash string, will map
+ * to one bucket. Each bucket maps to one or several peer servers, each running memcached.
+ * A majority of peers must agree for a lock to be acquired.
+ *
+ * @ingroup LockManager
+ * @since 1.20
+ */
+class MemcLockManager extends QuorumLockManager {
+	/** @var Array Mapping of lock types to the type actually used */
+	protected $lockTypeMap = array(
+		self::LOCK_SH => self::LOCK_SH,
+		self::LOCK_UW => self::LOCK_SH,
+		self::LOCK_EX => self::LOCK_EX
+	);
+
+	/** @var Array Map server names to MemcachedBagOStuff objects */
+	protected $bagOStuffs = array();
+	/** @var Array */
+	protected $serversUp = array(); // (server name => bool)
+
+	protected $lockExpiry; // integer; maximum time locks can be held
+	protected $session = ''; // string; random SHA-1 UUID
+	protected $wikiId = ''; // string
+
+	/**
+	 * Construct a new instance from configuration.
+	 *
+	 * $config paramaters include:
+	 *   - lockServers  : Associative array of server names to "<IP>:<port>" strings.
+	 *   - srvsByBucket : Array of 1-16 consecutive integer keys, starting from 0,
+	 *                    each having an odd-numbered list of server names (peers) as values.
+	 *   - memcConfig   : Configuration array for ObjectCache::newFromParams. [optional]
+	 *                    If set, this must use one of the memcached classes.
+	 *   - wikiId       : Wiki ID string that all resources are relative to. [optional]
+	 *
+	 * @param Array $config
+	 */
+	public function __construct( array $config ) {
+		parent::__construct( $config );
+
+		// Sanitize srvsByBucket config to prevent PHP errors
+		$this->srvsByBucket = array_filter( $config['srvsByBucket'], 'is_array' );
+		$this->srvsByBucket = array_values( $this->srvsByBucket ); // consecutive
+
+		$memcConfig = isset( $config['memcConfig'] )
+			? $config['memcConfig']
+			: array( 'class' => 'MemcachedPhpBagOStuff' );
+
+		foreach ( $config['lockServers'] as $name => $address ) {
+			$params = array( 'servers' => array( $address ) ) + $memcConfig;
+			$cache = ObjectCache::newFromParams( $params );
+			if ( $cache instanceof MemcachedBagOStuff ) {
+				$this->bagOStuffs[$name] = $cache;
+			} else {
+				throw new MWException(
+					'Only MemcachedBagOStuff classes are supported by MemcLockManager.' );
+			}
+		}
+
+		$this->wikiId = isset( $config['wikiId'] ) ? $config['wikiId'] : wfWikiID();
+
+		$met = ini_get( 'max_execution_time' ); // this is 0 in CLI mode
+		$this->lockExpiry = $met ? 2*(int)$met : 2*3600;
+
+		$this->session = wfRandomString( 32 );
+	}
+
+	/**
+	 * @see QuorumLockManager::getLocksOnServer()
+	 * @return Status
+	 */
+	protected function getLocksOnServer( $lockSrv, array $paths, $type ) {
+		$status = Status::newGood();
+
+		$memc = $this->getCache( $lockSrv );
+		$keys = array_map( array( $this, 'recordKeyForPath' ), $paths ); // lock records
+
+		// Lock all of the active lock record keys...
+		if ( !$this->acquireMutexes( $memc, $keys ) ) {
+			foreach ( $paths as $path ) {
+				$status->fatal( 'lockmanager-fail-acquirelock', $path );
+			}
+			return;
+		}
+
+		// Fetch all the existing lock records...
+		$lockRecords = $memc->getMulti( $keys );
+
+		$now = time();
+		// Check if the requested locks conflict with existing ones...
+		foreach ( $paths as $path ) {
+			$locksKey = $this->recordKeyForPath( $path );
+			$locksHeld = isset( $lockRecords[$locksKey] )
+				? $lockRecords[$locksKey]
+				: array( self::LOCK_SH => array(), self::LOCK_EX => array() ); // init
+			foreach ( $locksHeld[self::LOCK_EX] as $session => $expiry ) {
+				if ( $expiry < $now ) { // stale?
+					unset( $locksHeld[self::LOCK_EX][$session] );
+				} elseif ( $session !== $this->session ) {
+					$status->fatal( 'lockmanager-fail-acquirelock', $path );
+				}
+			}
+			if ( $type === self::LOCK_EX ) {
+				foreach ( $locksHeld[self::LOCK_SH] as $session => $expiry ) {
+					if ( $expiry < $now ) { // stale?
+						unset( $locksHeld[self::LOCK_SH][$session] );
+					} elseif ( $session !== $this->session ) {
+						$status->fatal( 'lockmanager-fail-acquirelock', $path );
+					}
+				}
+			}
+			if ( $status->isOK() ) {
+				// Register the session in the lock record array
+				$locksHeld[$type][$this->session] = $now + $this->lockExpiry;
+				// We will update this record if none of the other locks conflict
+				$lockRecords[$locksKey] = $locksHeld;
+			}
+		}
+
+		// If there were no lock conflicts, update all the lock records...
+		if ( $status->isOK() ) {
+			foreach ( $lockRecords as $locksKey => $locksHeld ) {
+				$memc->set( $locksKey, $locksHeld );
+				wfDebug( __METHOD__ . ": acquired lock on key $locksKey.\n" );
+			}
+		}
+
+		// Unlock all of the active lock record keys...
+		$this->releaseMutexes( $memc, $keys );
+
+		return $status;
+	}
+
+	/**
+	 * @see QuorumLockManager::freeLocksOnServer()
+	 * @return Status
+	 */
+	protected function freeLocksOnServer( $lockSrv, array $paths, $type ) {
+		$status = Status::newGood();
+
+		$memc = $this->getCache( $lockSrv );
+		$keys = array_map( array( $this, 'recordKeyForPath' ), $paths ); // lock records
+
+		// Lock all of the active lock record keys...
+		if ( !$this->acquireMutexes( $memc, $keys ) ) {
+			foreach ( $paths as $path ) {
+				$status->fatal( 'lockmanager-fail-releaselock', $path );
+			}
+			return;
+		}
+
+		// Fetch all the existing lock records...
+		$lockRecords = $memc->getMulti( $keys );
+
+		// Remove the requested locks from all records...
+		foreach ( $paths as $path ) {
+			$locksKey = $this->recordKeyForPath( $path ); // lock record
+			if ( !isset( $lockRecords[$locksKey] ) ) {
+				continue; // nothing to do
+			}
+			$locksHeld = $lockRecords[$locksKey];
+			if ( is_array( $locksHeld ) && isset( $locksHeld[$type] ) ) {
+				unset( $locksHeld[$type][$this->session] );
+				$ok = $memc->set( $locksKey, $locksHeld );
+			} else {
+				$ok = true;
+			}
+			if ( !$ok ) {
+				$status->fatal( 'lockmanager-fail-releaselock', $path );
+			}
+			wfDebug( __METHOD__ . ": released lock on key $locksKey.\n" );
+		}
+
+		// Unlock all of the active lock record keys...
+		$this->releaseMutexes( $memc, $keys );
+
+		return $status;
+	}
+
+	/**
+	 * @see QuorumLockManager::releaseAllLocks()
+	 * @return Status
+	 */
+	protected function releaseAllLocks() {
+		return Status::newGood(); // not supported
+	}
+
+	/**
+	 * @see QuorumLockManager::isServerUp()
+	 * @return bool
+	 */
+	protected function isServerUp( $lockSrv ) {
+		return (bool)$this->getCache( $lockSrv );
+	}
+
+	/**
+	 * Get the MemcachedBagOStuff object for a $lockSrv
+	 *
+	 * @param $lockSrv string Server name
+	 * @return MemcachedBagOStuff|null
+	 */
+	protected function getCache( $lockSrv ) {
+		$memc = null;
+		if ( isset( $this->bagOStuffs[$lockSrv] ) ) {
+			$memc = $this->bagOStuffs[$lockSrv];
+			if ( !isset( $this->serversUp[$lockSrv] ) ) {
+				$this->serversUp[$lockSrv] = $memc->set( 'MemcLockManager:ping', 1, 1 );
+				if ( !$this->serversUp[$lockSrv] ) {
+					trigger_error( __METHOD__ . ": Could not contact $lockSrv.", E_USER_WARNING );
+				}
+			}
+			if ( !$this->serversUp[$lockSrv] ) {
+				return null; // server appears to be down
+			}
+		}
+		return $memc;
+	}
+
+	/**
+	 * @param $path string
+	 * @return string
+	 */
+	protected function recordKeyForPath( $path ) {
+		$hash = LockManager::sha1Base36( $path );
+		list( $db, $prefix ) = wfSplitWikiID( $this->wikiId );
+		return wfForeignMemcKey( $db, $prefix, __CLASS__, 'locks', $hash );
+	}
+
+	/**
+	 * @param $memc MemcachedBagOStuff
+	 * @param $keys Array List of keys to acquire
+	 * @return bool
+	 */
+	protected function acquireMutexes( MemcachedBagOStuff $memc, array $keys ) {
+		$lockedKeys = array();
+
+		// Acquire the keys in lexicographical order, to avoid deadlock problems.
+		// If P1 is waiting to acquire a key P2 has, P2 can't also be waiting for a key P1 has.
+		sort( $keys );
+
+		// Try to quickly loop to acquire the keys, but back off after a few rounds.
+		// This reduces memcached spam, especially in the rare case where a server acquires
+		// some lock keys and dies without releasing them. Lock keys expire after a few minutes.
+		$rounds = 0;
+		$start = microtime( true );
+		do {
+			if ( ( ++$rounds % 4 ) == 0 ) {
+				usleep( 1000*50 ); // 50 ms
+			}
+			foreach ( array_diff( $keys, $lockedKeys ) as $key ) {
+				if ( $memc->add( "$key:mutex", 1, 180 ) ) { // lock record
+					$lockedKeys[] = $key;
+				} else {
+					continue; // acquire in order
+				}
+			}
+		} while ( count( $lockedKeys ) < count( $keys ) && ( microtime( true ) - $start ) <= 6 );
+
+		if ( count( $lockedKeys ) != count( $keys ) ) {
+			$this->releaseMutexes( $lockedKeys ); // failed; release what was locked
+			return false;
+		}
+
+		return true;
+	}
+
+	/**
+	 * @param $memc MemcachedBagOStuff
+	 * @param $keys Array List of acquired keys
+	 * @return void
+	 */
+	protected function releaseMutexes( MemcachedBagOStuff $memc, array $keys ) {
+		foreach ( $keys as $key ) {
+			$memc->delete( "$key:mutex" );
+		}
+	}
+
+	/**
+	 * Make sure remaining locks get cleared for sanity
+	 */
+	function __destruct() {
+		while ( count( $this->locksHeld ) ) {
+			foreach ( $this->locksHeld as $path => $locks ) {
+				$this->doUnlock( array( $path ), self::LOCK_EX );
+				$this->doUnlock( array( $path ), self::LOCK_SH );
+			}
+		}
+	}
+}