Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Core\Breadcrumb;
Chris@0: 
Chris@0: use Drupal\Core\Extension\ModuleHandlerInterface;
Chris@0: use Drupal\Core\Routing\RouteMatchInterface;
Chris@0: 
Chris@0: /**
Chris@0:  * Provides a breadcrumb manager.
Chris@0:  *
Chris@0:  * Can be assigned any number of BreadcrumbBuilderInterface objects by calling
Chris@0:  * the addBuilder() method. When build() is called it iterates over the objects
Chris@0:  * in priority order and uses the first one that returns TRUE from
Chris@0:  * BreadcrumbBuilderInterface::applies() to build the breadcrumbs.
Chris@0:  *
Chris@0:  * @see \Drupal\Core\DependencyInjection\Compiler\RegisterBreadcrumbBuilderPass
Chris@0:  */
Chris@0: class BreadcrumbManager implements ChainBreadcrumbBuilderInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * The module handler to invoke the alter hook.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Extension\ModuleHandlerInterface
Chris@0:    */
Chris@0:   protected $moduleHandler;
Chris@0: 
Chris@0:   /**
Chris@0:    * Holds arrays of breadcrumb builders, keyed by priority.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $builders = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * Holds the array of breadcrumb builders sorted by priority.
Chris@0:    *
Chris@0:    * Set to NULL if the array needs to be re-calculated.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Breadcrumb\BreadcrumbBuilderInterface[]|null
Chris@0:    */
Chris@0:   protected $sortedBuilders;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a \Drupal\Core\Breadcrumb\BreadcrumbManager object.
Chris@0:    *
Chris@0:    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
Chris@0:    *   The module handler.
Chris@0:    */
Chris@0:   public function __construct(ModuleHandlerInterface $module_handler) {
Chris@0:     $this->moduleHandler = $module_handler;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function addBuilder(BreadcrumbBuilderInterface $builder, $priority) {
Chris@0:     $this->builders[$priority][] = $builder;
Chris@0:     // Force the builders to be re-sorted.
Chris@0:     $this->sortedBuilders = NULL;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function applies(RouteMatchInterface $route_match) {
Chris@0:     return TRUE;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function build(RouteMatchInterface $route_match) {
Chris@0:     $breadcrumb = new Breadcrumb();
Chris@0:     $context = ['builder' => NULL];
Chris@0:     // Call the build method of registered breadcrumb builders,
Chris@0:     // until one of them returns an array.
Chris@0:     foreach ($this->getSortedBuilders() as $builder) {
Chris@0:       if (!$builder->applies($route_match)) {
Chris@0:         // The builder does not apply, so we continue with the other builders.
Chris@0:         continue;
Chris@0:       }
Chris@0: 
Chris@0:       $breadcrumb = $builder->build($route_match);
Chris@0: 
Chris@0:       if ($breadcrumb instanceof Breadcrumb) {
Chris@0:         $context['builder'] = $builder;
Chris@0:         break;
Chris@0:       }
Chris@0:       else {
Chris@0:         throw new \UnexpectedValueException('Invalid breadcrumb returned by ' . get_class($builder) . '::build().');
Chris@0:       }
Chris@0:     }
Chris@0:     // Allow modules to alter the breadcrumb.
Chris@0:     $this->moduleHandler->alter('system_breadcrumb', $breadcrumb, $route_match, $context);
Chris@0: 
Chris@0:     return $breadcrumb;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the sorted array of breadcrumb builders.
Chris@0:    *
Chris@0:    * @return \Drupal\Core\Breadcrumb\BreadcrumbBuilderInterface[]
Chris@0:    *   An array of breadcrumb builder objects.
Chris@0:    */
Chris@0:   protected function getSortedBuilders() {
Chris@0:     if (!isset($this->sortedBuilders)) {
Chris@0:       // Sort the builders according to priority.
Chris@0:       krsort($this->builders);
Chris@0:       // Merge nested builders from $this->builders into $this->sortedBuilders.
Chris@0:       $this->sortedBuilders = [];
Chris@0:       foreach ($this->builders as $builders) {
Chris@0:         $this->sortedBuilders = array_merge($this->sortedBuilders, $builders);
Chris@0:       }
Chris@0:     }
Chris@0:     return $this->sortedBuilders;
Chris@0:   }
Chris@0: 
Chris@0: }