1 files changed, 162 insertions, 0 deletions
diff --git a/lib/private/lock/dblockingprovider.php b/lib/private/lock/dblockingprovider.php
new file mode 100644
index 00000000000..f3e684d0b4d
--- /dev/null
+++ b/lib/private/lock/dblockingprovider.php
@@ -0,0 +1,162 @@
+<?php
+/**
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\Lock;
+
+use OCP\IDBConnection;
+use OCP\ILogger;
+use OCP\Lock\LockedException;
+
+/**
+ * Locking provider that stores the locks in the database
+ */
+class DBLockingProvider extends AbstractLockingProvider {
+	/**
+	 * @var \OCP\IDBConnection
+	 */
+	private $connection;
+
+	/**
+	 * @var \OCP\ILogger
+	 */
+	private $logger;
+
+	/**
+	 * @param \OCP\IDBConnection $connection
+	 * @param \OCP\ILogger $logger
+	 */
+	public function __construct(IDBConnection $connection, ILogger $logger) {
+		$this->connection = $connection;
+		$this->logger = $logger;
+	}
+
+	protected function initLockField($path) {
+		$this->connection->insertIfNotExist('*PREFIX*file_locks', ['key' => $path, 'lock' => 0, 'ttl' => 0], ['key']);
+	}
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 * @return bool
+	 */
+	public function isLocked($path, $type) {
+		$query = $this->connection->prepare('SELECT `lock` from `*PREFIX*file_locks` WHERE `key` = ?');
+		$query->execute([$path]);
+		$lockValue = (int)$query->fetchColumn();
+		if ($type === self::LOCK_SHARED) {
+			return $lockValue > 0;
+		} else if ($type === self::LOCK_EXCLUSIVE) {
+			return $lockValue === -1;
+		} else {
+			return false;
+		}
+	}
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 * @throws \OCP\Lock\LockedException
+	 */
+	public function acquireLock($path, $type) {
+		if ($this->connection->inTransaction()){
+			$this->logger->warning("Trying to acquire a lock for '$path' while inside a transition");
+		}
+
+		$this->connection->beginTransaction();
+		$this->initLockField($path);
+		if ($type === self::LOCK_SHARED) {
+			$result = $this->connection->executeUpdate(
+				'UPDATE `*PREFIX*file_locks` SET `lock` = `lock` + 1 WHERE `key` = ? AND `lock` >= 0',
+				[$path]
+			);
+		} else {
+			$result = $this->connection->executeUpdate(
+				'UPDATE `*PREFIX*file_locks` SET `lock` = -1 WHERE `key` = ? AND `lock` = 0',
+				[$path]
+			);
+		}
+		$this->connection->commit();
+		if ($result !== 1) {
+			throw new LockedException($path);
+		}
+		$this->markAcquire($path, $type);
+	}
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 */
+	public function releaseLock($path, $type) {
+		$this->initLockField($path);
+		if ($type === self::LOCK_SHARED) {
+			$this->connection->executeUpdate(
+				'UPDATE `*PREFIX*file_locks` SET `lock` = `lock` - 1 WHERE `key` = ? AND `lock` > 0',
+				[$path]
+			);
+		} else {
+			$this->connection->executeUpdate(
+				'UPDATE `*PREFIX*file_locks` SET `lock` = 0 WHERE `key` = ? AND `lock` = -1',
+				[$path]
+			);
+		}
+
+		$this->markRelease($path, $type);
+	}
+
+	/**
+	 * Change the type of an existing lock
+	 *
+	 * @param string $path
+	 * @param int $targetType self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 * @throws \OCP\Lock\LockedException
+	 */
+	public function changeLock($path, $targetType) {
+		$this->initLockField($path);
+		if ($targetType === self::LOCK_SHARED) {
+			$result = $this->connection->executeUpdate(
+				'UPDATE `*PREFIX*file_locks` SET `lock` = 1 WHERE `key` = ? AND `lock` = -1',
+				[$path]
+			);
+		} else {
+			$result = $this->connection->executeUpdate(
+				'UPDATE `*PREFIX*file_locks` SET `lock` = -1 WHERE `key` = ? AND `lock` = 1',
+				[$path]
+			);
+		}
+		if ($result !== 1) {
+			throw new LockedException($path);
+		}
+		$this->markChange($path, $targetType);
+	}
+
+	/**
+	 * cleanup empty locks
+	 */
+	public function cleanEmptyLocks() {
+		$this->connection->executeUpdate(
+			'DELETE FROM `*PREFIX*file_locks` WHERE `lock` = 0'
+		);
+	}
+
+	public function __destruct() {
+		$this->cleanEmptyLocks();
+	}
+}