add memcache based shared/exclusive locking

3 files changed, 158 insertions, 0 deletions

diff --git a/lib/private/lock/memcachelockingprovider.php b/lib/private/lock/memcachelockingprovider.php
new file mode 100644
index 00000000000..43fdf70bc8b
--- /dev/null
+++ b/lib/private/lock/memcachelockingprovider.php
@@ -0,0 +1,86 @@
+<?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\Lock\ILockingProvider;
+use OCP\Lock\LockedException;
+use OCP\IMemcache;
+
+class MemcacheLockingProvider implements ILockingProvider {
+	/**
+	 * @var \OCP\IMemcache
+	 */
+	private $memcache;
+
+	/**
+	 * @param \OCP\IMemcache $memcache
+	 */
+	public function __construct(IMemcache $memcache) {
+		$this->memcache = $memcache;
+	}
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 * @return bool
+	 */
+	public function isLocked($path, $type) {
+		$lockValue = $this->memcache->get($path);
+		if ($type === self::LOCK_SHARED) {
+			return $lockValue > 0;
+		} else if ($type === self::LOCK_EXCLUSIVE) {
+			return $lockValue === 'exclusive';
+		} else {
+			return false;
+		}
+	}
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 * @throws \OCP\Lock\LockedException
+	 */
+	public function acquireLock($path, $type) {
+		if ($type === self::LOCK_SHARED) {
+			if (!$this->memcache->inc($path)) {
+				throw new LockedException($path . ' is locked');
+			}
+		} else {
+			$this->memcache->add($path, 0);
+			if (!$this->memcache->cas($path, 0, 'exclusive')) {
+				throw new LockedException($path . ' is locked');
+			}
+		}
+	}
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 */
+	public function releaseLock($path, $type) {
+		if ($type === self::LOCK_SHARED) {
+			$this->memcache->dec($path);
+		} else if ($type === self::LOCK_EXCLUSIVE) {
+			$this->memcache->cas($path, 'exclusive', 0);
+		}
+	}
+}
diff --git a/lib/public/lock/ilockingprovider.php b/lib/public/lock/ilockingprovider.php
new file mode 100644
index 00000000000..a584ec02ef6
--- /dev/null
+++ b/lib/public/lock/ilockingprovider.php
@@ -0,0 +1,47 @@
+<?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 OCP\Lock;
+
+interface ILockingProvider {
+	const LOCK_SHARED = 1;
+	const LOCK_EXCLUSIVE = 2;
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 * @return bool
+	 */
+	public function isLocked($path, $type);
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 * @throws \OCP\Files\Lock\LockedException
+	 */
+	public function acquireLock($path, $type);
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 */
+	public function releaseLock($path, $type);
+}
diff --git a/lib/public/lock/lockedexception.php b/lib/public/lock/lockedexception.php
new file mode 100644
index 00000000000..4c0ca9b8c5b
--- /dev/null
+++ b/lib/public/lock/lockedexception.php
@@ -0,0 +1,25 @@
+<?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 OCP\Lock;
+
+class LockedException extends \Exception {
+}