+<?php
+
+namespace Drupal\forum\Breadcrumb;
+
+use Drupal\Core\Breadcrumb\BreadcrumbBuilderInterface;
+use Drupal\Core\Breadcrumb\Breadcrumb;
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Entity\EntityManagerInterface;
+use Drupal\Core\Link;
+use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\Core\StringTranslation\TranslationInterface;
+use Drupal\forum\ForumManagerInterface;
+
+/**
+ * Provides a forum breadcrumb base class.
+ *
+ * This just holds the dependency-injected config, entity manager, and forum
+ * manager objects.
+ */
+abstract class ForumBreadcrumbBuilderBase implements BreadcrumbBuilderInterface {
+ use StringTranslationTrait;
+
+ /**
+ * Configuration object for this builder.
+ *
+ * @var \Drupal\Core\Config\Config
+ */
+ protected $config;
+
+ /**
+ * The entity manager.
+ *
+ * @var \Drupal\Core\Entity\EntityManagerInterface
+ */
+ protected $entityManager;
+
+ /**
+ * The forum manager service.
+ *
+ * @var \Drupal\forum\ForumManagerInterface
+ */
+ protected $forumManager;
+
+ /**
+ * Constructs a forum breadcrumb builder object.
+ *
+ * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
+ * The entity manager.
+ * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+ * The configuration factory.
+ * @param \Drupal\forum\ForumManagerInterface $forum_manager
+ * The forum manager service.
+ * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
+ * The string translation service.
+ */
+ public function __construct(EntityManagerInterface $entity_manager, ConfigFactoryInterface $config_factory, ForumManagerInterface $forum_manager, TranslationInterface $string_translation) {
+ $this->entityManager = $entity_manager;
+ $this->config = $config_factory->get('forum.settings');
+ $this->forumManager = $forum_manager;
+ $this->setStringTranslation($string_translation);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function build(RouteMatchInterface $route_match) {
+ $breadcrumb = new Breadcrumb();
+ $breadcrumb->addCacheContexts(['route']);
+
+ $links[] = Link::createFromRoute($this->t('Home'), '<front>');
+
+ $vocabulary = $this->entityManager
+ ->getStorage('taxonomy_vocabulary')
+ ->load($this->config->get('vocabulary'));
+ $breadcrumb->addCacheableDependency($vocabulary);
+ $links[] = Link::createFromRoute($vocabulary->label(), 'forum.index');
+
+ return $breadcrumb->setLinks($links);
+ }
+
+}