Add memcached backend

lib/memcache/cache.php

@@ -20,6 +20,8 @@ abstract class Cache {
 			return new XCache($global);
 		} elseif (APC::isAvailable()) {
 			return new APC($global);
+		} elseif (Memcached::isAvailable()) {
+			return new Memcached($global);
 		} else {
 			return null;
 		}
@@ -65,5 +67,7 @@ abstract class Cache {
 	/**
 	 * @return bool
 	 */
-	//static public function isAvailable();
+	static public function isAvailable() {
+		return XCache::isAvailable() || APC::isAvailable() || Memcached::isAvailable();
+	}
 }

lib/memcache/memcached.php

+<?php
+/**
+ * Copyright (c) 2012 Bart Visscher <bartv@thisnet.nl>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+namespace OC\Memcache;
+
+class Memcached extends Cache {
+	protected $prefix;
+
+	/**
+	 * @var \Memcached $cache
+	 */
+	private static $cache = null;
+
+	public function __construct($global = false) {
+		$this->prefix = \OC_Util::getInstanceId() . '/';
+		if (!$global) {
+			$this->prefix .= \OC_User::getUser() . '/';
+		}
+		if (is_null(self::$cache)) {
+			self::$cache = new \Memcached();
+			list($host, $port) = \OC_Config::getValue('memcached_server', array('localhost', 11211));
+			self::$cache->addServer($host, $port);
+		}
+	}
+
+	/**
+	 * entries in XCache gets namespaced to prevent collisions between owncloud instances and users
+	 */
+	protected function getNameSpace() {
+		return $this->prefix;
+	}
+
+	public function get($key) {
+		$result = self::$cache->get($this->getNamespace() . $key);
+		if ($result === false and self::$cache->getResultCode() == \Memcached::RES_NOTFOUND) {
+			return null;
+		} else {
+			return $result;
+		}
+	}
+
+	public function set($key, $value, $ttl = 0) {
+		if ($ttl > 0) {
+			return self::$cache->set($this->getNamespace() . $key, $value, $ttl);
+		} else {
+			return self::$cache->set($this->getNamespace() . $key, $value);
+		}
+	}
+
+	public function hasKey($key) {
+		self::$cache->get($this->getNamespace() . $key);
+		return self::$cache->getResultCode() !== \Memcached::RES_NOTFOUND;
+	}
+
+	public function remove($key) {
+		return self::$cache->delete($this->getNamespace() . $key);
+	}
+
+	public function clear($prefix = '') {
+		$prefix = $this->getNamespace() . $prefix;
+		$allKeys = self::$cache->getAllKeys();
+		$keys = array();
+		$prefixLength = strlen($prefix);
+		foreach ($allKeys as $key) {
+			if (substr($key, 0, $prefixLength) === $prefix) {
+				$keys[] = $key;
+			}
+		}
+		self::$cache->deleteMulti($keys);
+		return true;
+	}
+
+	static public function isAvailable() {
+		return extension_loaded('memcached');
+	}
+}

tests/lib/memcache/memcached.php

+<?php
+/**
+ * Copyright (c) 2013 Robin Appelman <icewind@owncloud.com>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+class Test_Memcache_Memcached extends Test_Cache {
+	public function setUp() {
+		if (!\OC\Memcache\Memcached::isAvailable()) {
+			$this->markTestSkipped('The memcached extension is not available.');
+			return;
+		}
+		$this->instance = new \OC\Memcache\Memcached();
+	}
+}