setStringTranslation($translation); } /** * Adds an "overview" child link to second level menu links with children. * * In the navigation menu, a second-level menu item is a link if it does not * have children, but if it does, it instead becomes a button that opens * its child menu. To provide a way to access the page a second-level menu * item links to, add an "overview" link that links to the page as a child * (third-level) menu item. * * @param \Drupal\Core\Menu\MenuLinkTreeElement[] $tree * The menu link tree to manipulate. * * @return \Drupal\Core\Menu\MenuLinkTreeElement[] * The manipulated menu link tree. */ public function addSecondLevelOverviewLinks(array $tree): array { if (!$tree) { return []; } foreach ($tree as $item) { if (!$this->isEnabledAndAccessible($item)) { continue; } foreach ($item->subtree as $sub_item) { if ($this->shouldAddOverviewLink($sub_item)) { $this->addOverviewLink($sub_item); } } } return $tree; } /** * Whether a menu tree element should have an overview link added to it. * * @param \Drupal\Core\Menu\MenuLinkTreeElement $element * The menu link tree element to check. * * @return bool * TRUE if menu tree element should have a child overview link added. */ protected function shouldAddOverviewLink(MenuLinkTreeElement $element): bool { if (empty($element->subtree) || !$this->isEnabledAndAccessible($element)) { return FALSE; } $route_name = $element->link->getRouteName(); if (in_array($route_name, ['', ''])) { return FALSE; } $has_visible_children = FALSE; foreach ($element->subtree as $sub_element) { // Do not add overview link if there are no accessible or enabled // children. if ($this->isEnabledAndAccessible($sub_element)) { $has_visible_children = TRUE; } // Do not add overview link if there is already a child linking to the // same URL. if ($sub_element->link->getRouteName() === $route_name) { return FALSE; } } if (!$has_visible_children) { return FALSE; } // The systemAdminMenuBlockPage() method in SystemController returns a list // of child menu links for the page. If the second-level menu item link's // route uses that controller, do not add the overview link, because that // duplicates what is already in the navigation menu. try { $controller = ltrim($this->routeProvider->getRouteByName($route_name)->getDefault('_controller') ?? '', "\\"); return $controller !== SystemController::class . '::systemAdminMenuBlockPage'; } catch (RouteNotFoundException) { return TRUE; } } /** * Checks whether the menu link tree element is accessible and enabled. * * Generally, the 'checkAccess' manipulator should run before this manipulator * does, so the access objects should be set on all the links, but if it is * not, treat the link as accessible for the purpose of adding the overview * child link. * * @param \Drupal\Core\Menu\MenuLinkTreeElement $element * The menu link tree element to be checked. * * @return bool * TRUE if the menu link tree element is enabled and has access allowed. */ protected function isEnabledAndAccessible(MenuLinkTreeElement $element): bool { return $element->link->isEnabled() && (!isset($element->access) || $element->access->isAllowed()); } /** * Adds "overview" menu tree element as child of a menu tree element. * * @param \Drupal\Core\Menu\MenuLinkTreeElement $element * The menu link tree element to add the overview child element to. */ protected function addOverviewLink(MenuLinkTreeElement $element): void { // Copy the menu link for the menu link element to a new menu link // definition, except with overrides to make 'Overview' the title, set the // parent to the original menu link, and set weight to a low number so that // it likely goes to the top. $definition = [ 'title' => $this->t('Overview', [ '@title' => $element->link->getTitle(), ]), 'parent' => $element->link->getPluginId(), 'provider' => 'navigation', 'weight' => -1000, ] + $element->link->getPluginDefinition(); $link = new MenuLinkDefault([], $element->link->getPluginId() . '.navigation_overview', $definition, $this->overrides); $overview_element = new MenuLinkTreeElement($link, FALSE, $element->depth + 1, $element->inActiveTrail, []); $overview_element->access = $element->access ? clone $element->access : NULL; $element->subtree[$element->link->getPluginId() . '.navigation_overview'] = $overview_element; } }