class NullGenerator

class NullGenerator extends UrlGenerator {
  
  /**
   * Override the parent constructor.
   *
   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
   *   The request stack.
   */
  public function __construct(RequestStack $request_stack) {
    $this->requestStack = $request_stack;
    $this->context = new RequestContext();
  }
  
  /**
   * {@inheritdoc}
   *
   * Methods generate(), generateFromRoute() and getPathFromRoute() all call
   * this protected method.
   */
  protected function getRoute($name) {
    if ($name === '<front>') {
      return new Route('/');
    }
    elseif ($name === '<current>') {
      return new Route($this->requestStack
        ->getCurrentRequest()
        ->getPathInfo());
    }
    elseif ($name === '<none>') {
      return new Route('');
    }
    throw new RouteNotFoundException();
  }
  
  /**
   * {@inheritdoc}
   */
  protected function processRoute($name, Route $route, array &$parameters, ?BubbleableMetadata $bubbleable_metadata = NULL) {
  }
  
  /**
   * {@inheritdoc}
   */
  protected function getInternalPathFromRoute($name, Route $route, $parameters = [], &$query_params = []) {
    return $route->getPath();
  }
  
  /**
   * {@inheritdoc}
   */
  protected function processPath($path, &$options = [], ?BubbleableMetadata $bubbleable_metadata = NULL) {
    return $path;
  }

}