1 files changed, 104 insertions, 0 deletions
diff --git a/includes/filebackend/lockmanager/ScopedLock.php b/includes/filebackend/lockmanager/ScopedLock.php
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+++ b/includes/filebackend/lockmanager/ScopedLock.php
@@ -0,0 +1,104 @@
+<?php
+/**
+ * Resource locking handling.
+ *
+ * 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
+ * @author Aaron Schulz
+ */
+
+/**
+ * Self-releasing locks
+ *
+ * LockManager helper class to handle scoped locks, which
+ * release when an object is destroyed or goes out of scope.
+ *
+ * @ingroup LockManager
+ * @since 1.19
+ */
+class ScopedLock {
+	/** @var LockManager */
+	protected $manager;
+	/** @var Status */
+	protected $status;
+	/** @var Array Map of lock types to resource paths */
+	protected $pathsByType;
+
+	/**
+	 * @param LockManager $manager
+	 * @param array $pathsByType Map of lock types to path lists
+	 * @param Status $status
+	 */
+	protected function __construct( LockManager $manager, array $pathsByType, Status $status ) {
+		$this->manager = $manager;
+		$this->pathsByType = $pathsByType;
+		$this->status = $status;
+	}
+
+	/**
+	 * Get a ScopedLock object representing a lock on resource paths.
+	 * Any locks are released once this object goes out of scope.
+	 * The status object is updated with any errors or warnings.
+	 *
+	 * $type can be "mixed" and $paths can be a map of types to paths (since 1.22).
+	 * Otherwise $type should be an integer and $paths should be a list of paths.
+	 *
+	 * @param LockManager $manager
+	 * @param array $paths List of storage paths or map of lock types to path lists
+	 * @param integer|string $type LockManager::LOCK_* constant or "mixed"
+	 * @param Status $status
+	 * @param integer $timeout Timeout in seconds (0 means non-blocking) (since 1.22)
+	 * @return ScopedLock|null Returns null on failure
+	 */
+	public static function factory(
+		LockManager $manager, array $paths, $type, Status $status, $timeout = 0
+	) {
+		$pathsByType = is_integer( $type ) ? array( $type => $paths ) : $paths;
+		$lockStatus = $manager->lockByType( $pathsByType, $timeout );
+		$status->merge( $lockStatus );
+		if ( $lockStatus->isOK() ) {
+			return new self( $manager, $pathsByType, $status );
+		}
+		return null;
+	}
+
+	/**
+	 * Release a scoped lock and set any errors in the attatched Status object.
+	 * This is useful for early release of locks before function scope is destroyed.
+	 * This is the same as setting the lock object to null.
+	 *
+	 * @param ScopedLock $lock
+	 * @return void
+	 * @since 1.21
+	 */
+	public static function release( ScopedLock &$lock = null ) {
+		$lock = null;
+	}
+
+	/**
+	 * Release the locks when this goes out of scope
+	 */
+	function __destruct() {
+		$wasOk = $this->status->isOK();
+		$this->status->merge( $this->manager->unlockByType( $this->pathsByType ) );
+		if ( $wasOk ) {
+			// Make sure status is OK, despite any unlockFiles() fatals
+			$this->status->setResult( true, $this->status->value );
+		}
+	}
+}