UrlMatcher.php

<?php

namespace Drupal\Core\Routing;

use Drupal\Core\Path\CurrentPathStack;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\RouteCollection;
use Symfony\Cmf\Component\Routing\NestedMatcher\UrlMatcher as BaseUrlMatcher;

/**
 * Drupal-specific URL Matcher; handles the Drupal "system path" mapping.
 */
class UrlMatcher extends BaseUrlMatcher {
    
    /**
     * The current path.
     *
     * @var \Drupal\Core\Path\CurrentPathStack
     */
    protected $currentPath;
    
    /**
     * Constructs a new UrlMatcher.
     *
     * The parent class has a constructor we need to skip, so just override it
     * with a no-op.
     *
     * @param \Drupal\Core\Path\CurrentPathStack $current_path
     *   The current path.
     */
    public function __construct(CurrentPathStack $current_path) {
        $this->currentPath = $current_path;
    }
    public function finalMatch(RouteCollection $collection, Request $request) {
        $this->routes = $collection;
        $context = new RequestContext();
        $context->fromRequest($request);
        $this->setContext($context);
        return $this->match($this->currentPath
            ->getPath($request));
    }

}