MenuActiveTrail.php

<?php

namespace Drupal\Core\Menu;

use Drupal\Core\Cache\CacheBackendInterface;
use Drupal\Core\Cache\CacheCollector;
use Drupal\Core\Lock\LockBackendInterface;
use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Provides the default implementation of the active menu trail service.
 *
 * It uses the current route name and route parameters to compare with the ones
 * of the menu links.
 */
class MenuActiveTrail extends CacheCollector implements MenuActiveTrailInterface {
    
    /**
     * The menu link plugin manager.
     *
     * @var \Drupal\Core\Menu\MenuLinkManagerInterface
     */
    protected $menuLinkManager;
    
    /**
     * The route match object for the current page.
     *
     * @var \Drupal\Core\Routing\RouteMatchInterface
     */
    protected $routeMatch;
    
    /**
     * Constructs a \Drupal\Core\Menu\MenuActiveTrail object.
     *
     * @param \Drupal\Core\Menu\MenuLinkManagerInterface $menu_link_manager
     *   The menu link plugin manager.
     * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
     *   A route match object for finding the active link.
     * @param \Drupal\Core\Cache\CacheBackendInterface $cache
     *   The cache backend.
     * @param \Drupal\Core\Lock\LockBackendInterface $lock
     *   The lock backend.
     */
    public function __construct(MenuLinkManagerInterface $menu_link_manager, RouteMatchInterface $route_match, CacheBackendInterface $cache, LockBackendInterface $lock) {
        parent::__construct(NULL, $cache, $lock);
        $this->menuLinkManager = $menu_link_manager;
        $this->routeMatch = $route_match;
    }
    
    /**
     * {@inheritdoc}
     *
     * @see ::getActiveTrailIds()
     */
    protected function getCid() {
        if (!isset($this->cid)) {
            $route_parameters = $this->routeMatch
                ->getRawParameters()
                ->all();
            ksort($route_parameters);
            $this->cid = 'active-trail:route:' . $this->routeMatch
                ->getRouteName() . ':route_parameters:' . serialize($route_parameters);
        }
        return $this->cid;
    }
    
    /**
     * {@inheritdoc}
     *
     * @see ::getActiveTrailIds()
     */
    protected function resolveCacheMiss($menu_name) {
        $this->storage[$menu_name] = $this->doGetActiveTrailIds($menu_name);
        $this->tags[] = 'config:system.menu.' . $menu_name;
        $this->persist($menu_name);
        return $this->storage[$menu_name];
    }
    
    /**
     * {@inheritdoc}
     *
     * This implementation caches all active trail IDs per route match for *all*
     * menus whose active trails are calculated on that page. This ensures 1 cache
     * get for all active trails per page load, rather than N.
     *
     * It uses the cache collector pattern to do this.
     *
     * @see ::get()
     * @see \Drupal\Core\Cache\CacheCollectorInterface
     * @see \Drupal\Core\Cache\CacheCollector
     */
    public function getActiveTrailIds($menu_name) {
        return $this->get($menu_name);
    }
    
    /**
     * Helper method for ::getActiveTrailIds().
     */
    protected function doGetActiveTrailIds($menu_name) {
        // Parent ids; used both as key and value to ensure uniqueness.
        // We always want all the top-level links with parent == ''.
        $active_trail = [
            '' => '',
        ];
        // If a link in the given menu indeed matches the route, then use it to
        // complete the active trail.
        if ($active_link = $this->getActiveLink($menu_name)) {
            if ($parents = $this->menuLinkManager
                ->getParentIds($active_link->getPluginId())) {
                $active_trail = $parents + $active_trail;
            }
        }
        return $active_trail;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getActiveLink($menu_name = NULL) {
        // Note: this is a very simple implementation. If you need more control
        // over the return value, such as matching a prioritized list of menu names,
        // you should substitute your own implementation for the 'menu.active_trail'
        // service in the container.
        // The menu links coming from the storage are already sorted by depth,
        // weight and ID.
        $found = NULL;
        $route_name = $this->routeMatch
            ->getRouteName();
        // On a default (not custom) 403 page the route name is NULL. On a custom
        // 403 page we will get the route name for that page, so we can consider
        // it a feature that a relevant menu tree may be displayed.
        if ($route_name) {
            $route_parameters = $this->routeMatch
                ->getRawParameters()
                ->all();
            // Load links matching this route.
            $links = $this->menuLinkManager
                ->loadLinksByRoute($route_name, $route_parameters, $menu_name);
            // Select the first matching link.
            if ($links) {
                $found = reset($links);
            }
        }
        return $found;
    }

}