redesign of locking & caching

- New Factory "CacheDriverFactory" for Cache and Locks
- Adding Redis/Memcached Locking
- Moved Lock to Core
- other improvements

src/Core/Lock.php

@@ -0,0 +1,145 @@
+<?php
+/**
+ * @file src/Util/Lock.php
+ */
+namespace Friendica\Core;
+
+/**
+ * @file src/Core/Lock.php
+ * @brief Functions for preventing parallel execution of functions
+ */
+
+use Friendica\Core\Cache\CacheDriverFactory;
+
+/**
+ * @brief This class contain Functions for preventing parallel execution of functions
+ */
+class Lock
+{
+	/**
+	 * @var Lock\ILockDriver;
+	 */
+	static $driver = null;
+
+	public static function init()
+	{
+		$lock_driver = Config::get('system', 'lock_driver', 'default');
+
+		try {
+			switch ($lock_driver) {
+				case 'memcache':
+					$cache_driver = CacheDriverFactory::create('memcache');
+					self::$driver = new Lock\CacheLockDriver($cache_driver);
+					break;
+
+				case 'memcached':
+					$cache_driver = CacheDriverFactory::create('memcached');
+					self::$driver = new Lock\CacheLockDriver($cache_driver);
+					break;
+
+				case 'redis':
+					$cache_driver = CacheDriverFactory::create('redis');
+					self::$driver = new Lock\CacheLockDriver($cache_driver);
+					break;
+
+				case 'database':
+					self::$driver = new Lock\DatabaseLockDriver();
+					break;
+
+				case 'semaphore':
+					self::$driver = new Lock\SemaphoreLockDriver();
+					break;
+
+				default:
+					self::useAutoDriver();
+			}
+		} catch (\Exception $exception) {
+			logger ('Driver \'' . $lock_driver . '\' failed - Fallback to \'useAutoDriver()\'');
+			self::useAutoDriver();
+		}
+	}
+
+	/**
+	 * @brief This method tries to find the best - local - locking method for Friendica
+	 *
+	 * The following sequence will be tried:
+	 * 1. Semaphore Locking
+	 * 2. Cache Locking
+	 * 3. Database Locking
+	 *
+	 */
+	private static function useAutoDriver() {
+
+		// 1. Try to use Semaphores for - local - locking
+		if (function_exists('sem_get')) {
+			try {
+				self::$driver = new Lock\SemaphoreLockDriver();
+				return;
+			} catch (\Exception $exception) {
+				logger ('Using Semaphore driver for locking failed: ' . $exception->getMessage());
+			}
+		}
+
+		// 2. Try to use Cache Locking (don't use the DB-Cache Locking because it works different!)
+		$cache_driver = Config::get('system', 'cache_driver', 'database');
+		if ($cache_driver != 'database') {
+			try {
+				$lock_driver = CacheDriverFactory::create($cache_driver);
+				self::$driver = new Lock\CacheLockDriver($lock_driver);
+				return;
+			} catch (\Exception $exception) {
+				logger('Using Cache driver for locking failed: ' . $exception->getMessage());
+			}
+		}
+
+		// 3. Use Database Locking as a Fallback
+		self::$driver = new Lock\DatabaseLockDriver();
+	}
+
+	/**
+	 * Returns the current cache driver
+	 *
+	 * @return Lock\ILockDriver;
+	 */
+	private static function getDriver()
+	{
+		if (self::$driver === null) {
+			self::init();
+		}
+
+		return self::$driver;
+	}
+
+	/**
+	 * @brief Acquires a lock for a given name
+	 *
+	 * @param string  $key Name of the lock
+	 * @param integer $timeout Seconds until we give up
+	 *
+	 * @return boolean Was the lock successful?
+	 */
+	public static function acquireLock($key, $timeout = 120)
+	{
+		return self::getDriver()->acquireLock($key, $timeout);
+	}
+
+	/**
+	 * @brief Releases a lock if it was set by us
+	 *
+	 * @param string $key Name of the lock
+	 * @return mixed
+	 */
+	public static function releaseLock($key)
+	{
+		return self::getDriver()->releaseLock($key);
+	}
+
+	/**
+	 * @brief Releases all lock that were set by us
+	 * @return void
+	 */
+	public static function releaseAll()
+	{
+		self::getDriver()->releaseAll();
+	}
+}