Lock now can use the memcache as well

src/Util/Lock.php

@@ -8,6 +8,8 @@ namespace Friendica\Util;
  *
  */
 
+use Friendica\Core\Config;
+use Memcache;
 use dba;
 use dbm;
 
@@ -15,6 +17,31 @@ use dbm;
  * @brief This class contain Functions for preventing parallel execution of functions
  */
 class Lock {
+       /**
+         * @brief Check for memcache and open a connection if configured
+         *
+         * @return object|boolean The memcache object - or "false" if not successful
+         */
+        public static function memcache() {
+                if (!function_exists('memcache_connect')) {
+                        return false;
+                }
+
+                if (!Config::get('system', 'memcache')) {
+                        return false;
+                }
+
+                $memcache_host = Config::get('system', 'memcache_host', '127.0.0.1');
+                $memcache_port = Config::get('system', 'memcache_port', 11211);
+
+                $memcache = new Memcache;
+
+                if (!$memcache->connect($memcache_host, $memcache_port)) {
+                        return false;
+                }
+
+                return $memcache;
+        }
 
 	/**
 	 * @brief Sets a lock for a given name
@@ -33,6 +60,33 @@ class Lock {
 		$got_lock = false;
 		$start = time();
 
+		$memcache = self::memcache();
+		if (is_object($memcache)) {
+			$cachekey = get_app()->get_hostname().";lock:".$fn_name;
+
+			do {
+				$lock = $memcache->get($cachekey);
+
+				if (!is_bool($lock)) {
+					$pid = (int)$lock;
+
+					// When the process id isn't used anymore, we can safely claim the lock for us.
+					// Or we do want to lock something that was already locked by us.
+					if (!posix_kill($pid, 0) OR ($pid == getmypid())) {
+						$lock = false;
+					}
+				}
+				if (is_bool($lock)) {
+					$memcache->set($cachekey, getmypid(), MEMCACHE_COMPRESSED, 300);
+					$got_lock = true;
+				}
+				if (!$got_lock) {
+					sleep($wait_sec);
+				}
+			} while (!$got_lock AND ((time() - $start) < $timeout));
+
+			return $got_lock;
+		}
 		do {
 			dba::lock('locks');
 			$lock = dba::select('locks', array('locked', 'pid'), array('name' => $fn_name), array('limit' => 1));
@@ -73,7 +127,34 @@ class Lock {
 	 * @param string $fn_name Name of the lock
 	 */
 	public static function remove($fn_name) {
+		$memcache = self::memcache();
+		if (is_object($memcache)) {
+			$cachekey = get_app()->get_hostname().";lock:".$fn_name;
+			$lock = $memcache->get($cachekey);
+
+			if (!is_bool($lock)) {
+				if ((int)$lock == getmypid()) {
+					$memcache->delete($cachekey);
+				}
+			}
+			return;
+		}
+
 		dba::update('locks', array('locked' => false, 'pid' => 0), array('name' => $fn_name, 'pid' => getmypid()));
 		return;
 	}
+
+	/**
+	 * @brief Removes all lock that were set by us
+	 */
+	public static function removeAll() {
+		$memcache = self::memcache();
+		if (is_object($memcache)) {
+			// We cannot delete all cache entries, but this doesn't matter with memcache
+			return;
+		}
+
+		dba::update('locks', array('locked' => false, 'pid' => 0), array('pid' => getmypid()));
+		return;
+	}
 }