public function resolveResorceSource($source = null)
    {
        // Base path to use
        $basePath = '../';

        // if no source has been specified
        // look up default source

        if ($source == null) {
            $source = "app/config/routing.yml";
        }

        // Check resource extension
        $extension = Path::getExtension($source);

        // Check if source is of a known type
        // And if not then use default: routing.yml
        if (!in_array($extension, self::$knownSourceTypes) && empty($extension)) {
            $source = $source . '/routing.yml';
        }

        return $basePath . $source;
    }