/** * Build singleton instance storage engine. * * @param string $engine * @param string $host * @param int $port * @param string $database * @param string|null $user * @param string|null $pass * * @return StorageInterface */ public static function instance($engine, $host, $port, $database, $user = null, $pass = null) { if (!isset(self::$instances[$engine])) { $engine = new StorageManager($engine, $host, $port, $database, $user, $pass); return $engine->getEngine(); } return self::$instances[$engine]; }