class LocalActionManager

class LocalActionManager extends DefaultPluginManager implements LocalActionManagerInterface {
  
  /**
   * Provides some default values for all local action plugins.
   *
   * @var array
   */
  protected $defaults = [
    // The plugin id. Set by the plugin system based on the top-level YAML key.
'id' => NULL,
    // The static title for the local action.
'title' => '',
    // The weight of the local action.
'weight' => NULL,
    // (Required) the route name used to generate a link.
'route_name' => NULL,
    // Default route parameters for generating links.
'route_parameters' => [],
    // Associative array of link options.
'options' => [],
    // The route names where this local action appears.
'appears_on' => [],
    // Default class for local action implementations.
'class' => 'Drupal\\Core\\Menu\\LocalActionDefault',
  ];
  
  /**
   * An argument resolver object.
   *
   * @var \Symfony\Component\HttpKernel\Controller\ArgumentResolverInterface
   */
  protected $argumentResolver;
  
  /**
   * The request stack.
   *
   * @var \Symfony\Component\HttpFoundation\RequestStack
   */
  protected $requestStack;
  
  /**
   * The current route match.
   *
   * @var \Drupal\Core\Routing\RouteMatchInterface
   */
  protected $routeMatch;
  
  /**
   * The route provider to load routes by name.
   *
   * @var \Drupal\Core\Routing\RouteProviderInterface
   */
  protected $routeProvider;
  
  /**
   * The access manager.
   *
   * @var \Drupal\Core\Access\AccessManagerInterface
   */
  protected $accessManager;
  
  /**
   * The current user.
   *
   * @var \Drupal\Core\Session\AccountInterface
   */
  protected $account;
  
  /**
   * The plugin instances.
   *
   * @var \Drupal\Core\Menu\LocalActionInterface[]
   */
  protected $instances = [];
  
  /**
   * Constructs a LocalActionManager object.
   *
   * @param \Symfony\Component\HttpKernel\Controller\ArgumentResolverInterface $argument_resolver
   *   An object to use in resolving route arguments.
   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
   *   The request stack.
   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
   *   The current route match.
   * @param \Drupal\Core\Routing\RouteProviderInterface $route_provider
   *   The route provider.
   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
   *   The module handler.
   * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
   *   Cache backend instance to use.
   * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
   *   The language manager.
   * @param \Drupal\Core\Access\AccessManagerInterface $access_manager
   *   The access manager.
   * @param \Drupal\Core\Session\AccountInterface $account
   *   The current user.
   */
  public function __construct(ArgumentResolverInterface $argument_resolver, RequestStack $request_stack, RouteMatchInterface $route_match, RouteProviderInterface $route_provider, ModuleHandlerInterface $module_handler, CacheBackendInterface $cache_backend, LanguageManagerInterface $language_manager, AccessManagerInterface $access_manager, AccountInterface $account) {
    // Skip calling the parent constructor, since that assumes annotation-based
    // discovery.
    $this->factory = new ContainerFactory($this, 'Drupal\\Core\\Menu\\LocalActionInterface');
    $this->argumentResolver = $argument_resolver;
    $this->requestStack = $request_stack;
    $this->routeMatch = $route_match;
    $this->routeProvider = $route_provider;
    $this->accessManager = $access_manager;
    $this->moduleHandler = $module_handler;
    $this->account = $account;
    $this->alterInfo('menu_local_actions');
    $this->setCacheBackend($cache_backend, 'local_action_plugins:' . $language_manager->getCurrentLanguage()
      ->getId(), [
      'local_action',
    ]);
  }
  
  /**
   * {@inheritdoc}
   */
  protected function getDiscovery() {
    if (!isset($this->discovery)) {
      $yaml_discovery = new YamlDiscovery('links.action', $this->moduleHandler
        ->getModuleDirectories());
      $yaml_discovery->addTranslatableProperty('title', 'title_context');
      $this->discovery = new ContainerDerivativeDiscoveryDecorator($yaml_discovery);
    }
    return $this->discovery;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getTitle(LocalActionInterface $local_action) {
    $controller = [
      $local_action,
      'getTitle',
    ];
    $arguments = $this->argumentResolver
      ->getArguments($this->requestStack
      ->getCurrentRequest(), $controller);
    return call_user_func_array($controller, $arguments);
  }
  
  /**
   * {@inheritdoc}
   */
  public function getActionsForRoute($route_appears) {
    if (!isset($this->instances[$route_appears])) {
      $route_names = [];
      $this->instances[$route_appears] = [];
      // @todo - optimize this lookup by compiling or caching.
      foreach ($this->getDefinitions() as $plugin_id => $action_info) {
        if (in_array($route_appears, $action_info['appears_on'])) {
          $plugin = $this->createInstance($plugin_id);
          $route_names[] = $plugin->getRouteName();
          $this->instances[$route_appears][$plugin_id] = $plugin;
        }
      }
      // Pre-fetch all the action route objects. This reduces the number of SQL
      // queries that would otherwise be triggered by the access manager.
      if (!empty($route_names)) {
        $this->routeProvider
          ->getRoutesByNames($route_names);
      }
    }
    $links = [];
    $cacheability = new CacheableMetadata();
    $cacheability->addCacheContexts([
      'route',
    ]);
    /** @var \Drupal\Core\Menu\LocalActionInterface $plugin */
    foreach ($this->instances[$route_appears] as $plugin_id => $plugin) {
      $route_name = $plugin->getRouteName();
      $route_parameters = $plugin->getRouteParameters($this->routeMatch);
      $access = $this->accessManager
        ->checkNamedRoute($route_name, $route_parameters, $this->account, TRUE);
      $links[$plugin_id] = [
        '#theme' => 'menu_local_action',
        '#link' => [
          'title' => $this->getTitle($plugin),
          'url' => Url::fromRoute($route_name, $route_parameters),
          'localized_options' => $plugin->getOptions($this->routeMatch),
        ],
        '#access' => $access,
        '#weight' => $plugin->getWeight(),
      ];
      $cacheability->addCacheableDependency($access)
        ->addCacheableDependency($plugin);
    }
    $cacheability->applyTo($links);
    return $links;
  }

}