From 86e757d2b3d7cc76bfa5bd22b5b06e7f963cda4f Mon Sep 17 00:00:00 2001
From: Roeland Jago Douma <rullzer@owncloud.com>
Date: Thu, 14 Apr 2016 08:28:16 +0200
Subject: Move \OC\Lock to PSR-4

---
 lib/private/Lock/MemcacheLockingProvider.php | 122 +++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 lib/private/Lock/MemcacheLockingProvider.php

(limited to 'lib/private/Lock/MemcacheLockingProvider.php')

diff --git a/lib/private/Lock/MemcacheLockingProvider.php b/lib/private/Lock/MemcacheLockingProvider.php
new file mode 100644
index 00000000000..536b29e2c28
--- /dev/null
+++ b/lib/private/Lock/MemcacheLockingProvider.php
@@ -0,0 +1,122 @@
+<?php
+/**
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, 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\IMemcacheTTL;
+use OCP\Lock\LockedException;
+use OCP\IMemcache;
+
+class MemcacheLockingProvider extends AbstractLockingProvider {
+	/**
+	 * @var \OCP\IMemcache
+	 */
+	private $memcache;
+
+	/**
+	 * @param \OCP\IMemcache $memcache
+	 * @param int $ttl
+	 */
+	public function __construct(IMemcache $memcache, $ttl = 3600) {
+		$this->memcache = $memcache;
+		$this->ttl = $ttl;
+	}
+
+	private function setTTL($path) {
+		if ($this->memcache instanceof IMemcacheTTL) {
+			$this->memcache->setTTL($path, $this->ttl);
+		}
+	}
+
+	/**
+	 * @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);
+			}
+		} else {
+			$this->memcache->add($path, 0);
+			if (!$this->memcache->cas($path, 0, 'exclusive')) {
+				throw new LockedException($path);
+			}
+		}
+		$this->setTTL($path);
+		$this->markAcquire($path, $type);
+	}
+
+	/**
+	 * @param string $path
+	 * @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
+	 */
+	public function releaseLock($path, $type) {
+		if ($type === self::LOCK_SHARED) {
+			if (isset($this->acquiredLocks['shared'][$path]) and $this->acquiredLocks['shared'][$path] > 0) {
+				$this->memcache->dec($path);
+				$this->memcache->cad($path, 0);
+			}
+		} else if ($type === self::LOCK_EXCLUSIVE) {
+			$this->memcache->cad($path, 'exclusive');
+		}
+		$this->markRelease($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, $targetType) {
+		if ($targetType === self::LOCK_SHARED) {
+			if (!$this->memcache->cas($path, 'exclusive', 1)) {
+				throw new LockedException($path);
+			}
+		} else if ($targetType === self::LOCK_EXCLUSIVE) {
+			// we can only change a shared lock to an exclusive if there's only a single owner of the shared lock
+			if (!$this->memcache->cas($path, 1, 'exclusive')) {
+				throw new LockedException($path);
+			}
+		}
+		$this->setTTL($path);
+		$this->markChange($path, $targetType);
+	}
+}
-- 
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