/**
* 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];
}
