Lock abstraction (like the Cache)

- adding interface
- adding seperate drivers
- moving Lock to the Core package

src/Core/Lock/ILockDriver.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Friendica\Core\Lock;
+
+/**
+ * Lock Driver Interface
+ *
+ * @author Philipp Holzer <admin@philipp.info>
+ */
+interface ILockDriver
+{
+	/**
+	 *
+	 * @brief Acquires a lock for a given name
+	 *
+	 * @param string  $key      The Name of the lock
+	 * @param integer $timeout  Seconds until we give up
+	 *
+	 * @return boolean Was the lock successful?
+	 */
+	public function acquireLock($key, $timeout = 120);
+
+	/**
+	 * @brief Releases a lock if it was set by us
+	 *
+	 * @param string $key Name of the lock
+	 *
+	 * @return mixed
+	 */
+	public function releaseLock($key);
+
+	/**
+	 * @brief Releases all lock that were set by us
+	 *
+	 * @return void
+	 */
+	public function releaseAll();
+}