--- /dev/null
+<?php
+
+namespace Drupal\Core\Block;
+
+use Drupal\Component\Plugin\FallbackPluginManagerInterface;
+use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Plugin\CategorizingPluginManagerTrait;
+use Drupal\Core\Plugin\Context\ContextAwarePluginManagerTrait;
+use Drupal\Core\Plugin\DefaultPluginManager;
+
+/**
+ * Manages discovery and instantiation of block plugins.
+ *
+ * @todo Add documentation to this class.
+ *
+ * @see \Drupal\Core\Block\BlockPluginInterface
+ */
+class BlockManager extends DefaultPluginManager implements BlockManagerInterface, FallbackPluginManagerInterface {
+
+ use CategorizingPluginManagerTrait {
+ getSortedDefinitions as traitGetSortedDefinitions;
+ getGroupedDefinitions as traitGetGroupedDefinitions;
+ }
+ use ContextAwarePluginManagerTrait;
+
+ /**
+ * Constructs a new \Drupal\Core\Block\BlockManager object.
+ *
+ * @param \Traversable $namespaces
+ * An object that implements \Traversable which contains the root paths
+ * keyed by the corresponding namespace to look for plugin implementations.
+ * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
+ * Cache backend instance to use.
+ * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+ * The module handler to invoke the alter hook with.
+ */
+ public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
+ parent::__construct('Plugin/Block', $namespaces, $module_handler, 'Drupal\Core\Block\BlockPluginInterface', 'Drupal\Core\Block\Annotation\Block');
+
+ $this->alterInfo('block');
+ $this->setCacheBackend($cache_backend, 'block_plugins');
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function processDefinition(&$definition, $plugin_id) {
+ parent::processDefinition($definition, $plugin_id);
+ $this->processDefinitionCategory($definition);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getSortedDefinitions(array $definitions = NULL) {
+ // Sort the plugins first by category, then by label.
+ $definitions = $this->traitGetSortedDefinitions($definitions, 'admin_label');
+ // Do not display the 'broken' plugin in the UI.
+ unset($definitions['broken']);
+ return $definitions;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getGroupedDefinitions(array $definitions = NULL) {
+ $definitions = $this->traitGetGroupedDefinitions($definitions, 'admin_label');
+ // Do not display the 'broken' plugin in the UI.
+ unset($definitions[$this->t('Block')]['broken']);
+ return $definitions;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getFallbackPluginId($plugin_id, array $configuration = []) {
+ return 'broken';
+ }
+
+}