Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/modules/block/src/Plugin/Derivative/ThemeLocalTask.php

@@ -0,0 +1,83 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\block\Plugin\Derivative\ThemeLocalTask.
+ */
+
+namespace Drupal\block\Plugin\Derivative;
+
+use Drupal\Component\Plugin\Derivative\DeriverBase;
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Extension\ThemeHandlerInterface;
+use Drupal\Core\Plugin\Discovery\ContainerDeriverInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides dynamic tabs based on active themes.
+ */
+class ThemeLocalTask extends DeriverBase implements ContainerDeriverInterface {
+
+  /**
+   * Stores the theme settings config object.
+   *
+   * @var \Drupal\Core\Config\Config
+   */
+  protected $config;
+
+  /**
+   * The theme handler.
+   *
+   * @var \Drupal\Core\Extension\ThemeHandlerInterface
+   */
+  protected $themeHandler;
+
+  /**
+   * Constructs a new ThemeLocalTask.
+   *
+   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+   *   The config factory.
+   * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
+   *   The theme handler.
+   */
+  public function __construct(ConfigFactoryInterface $config_factory, ThemeHandlerInterface $theme_handler) {
+    $this->config = $config_factory->get('system.theme');
+    $this->themeHandler = $theme_handler;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, $base_plugin_id) {
+    return new static(
+      $container->get('config.factory'),
+      $container->get('theme_handler')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDerivativeDefinitions($base_plugin_definition) {
+    $default_theme = $this->config->get('default');
+
+    foreach ($this->themeHandler->listInfo() as $theme_name => $theme) {
+      if ($theme->status) {
+        $this->derivatives[$theme_name] = $base_plugin_definition;
+        $this->derivatives[$theme_name]['title'] = $theme->info['name'];
+        $this->derivatives[$theme_name]['route_parameters'] = array('theme' => $theme_name);
+      }
+      // Default task!
+      if ($default_theme == $theme_name) {
+        $this->derivatives[$theme_name]['route_name'] = 'block.admin_display';
+        // Emulate default logic because without the base plugin id we can't
+        // change the base_route.
+        $this->derivatives[$theme_name]['weight'] = -10;
+
+        unset($this->derivatives[$theme_name]['route_parameters']);
+      }
+    }
+    return $this->derivatives;
+  }
+
+}

core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php

@@ -0,0 +1,188 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\block\Plugin\DisplayVariant\BlockPageVariant.
+ */
+
+namespace Drupal\block\Plugin\DisplayVariant;
+
+use Drupal\block\BlockRepositoryInterface;
+use Drupal\block\Event\BlockContextEvent;
+use Drupal\block\Event\BlockEvents;
+use Drupal\Core\Block\MainContentBlockPluginInterface;
+use Drupal\Core\Block\MessagesBlockPluginInterface;
+use Drupal\Core\Display\PageVariantInterface;
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Entity\EntityViewBuilderInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\Core\Display\VariantBase;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+
+/**
+ * Provides a page display variant that decorates the main content with blocks.
+ *
+ * To ensure essential information is displayed, each essential part of a page
+ * has a corresponding block plugin interface, so that BlockPageVariant can
+ * automatically provide a fallback in case no block for each of these
+ * interfaces is placed.
+ *
+ * @see \Drupal\Core\Block\MainContentBlockPluginInterface
+ * @see \Drupal\Core\Block\MessagesBlockPluginInterface
+ *
+ * @PageDisplayVariant(
+ *   id = "block_page",
+ *   admin_label = @Translation("Page with blocks")
+ * )
+ */
+class BlockPageVariant extends VariantBase implements PageVariantInterface, ContainerFactoryPluginInterface {
+
+  /**
+   * The block repository.
+   *
+   * @var \Drupal\block\BlockRepositoryInterface
+   */
+  protected $blockRepository;
+
+  /**
+   * The block view builder.
+   *
+   * @var \Drupal\Core\Entity\EntityViewBuilderInterface
+   */
+  protected $blockViewBuilder;
+
+  /**
+   * The Block entity type list cache tags.
+   *
+   * @var string[]
+   */
+  protected $blockListCacheTags;
+
+  /**
+   * The render array representing the main page content.
+   *
+   * @var array
+   */
+  protected $mainContent = [];
+
+  /**
+   * Constructs a new BlockPageVariant.
+   *
+   * @param array $configuration
+   *   A configuration array containing information about the plugin instance.
+   * @param string $plugin_id
+   *   The plugin ID for the plugin instance.
+   * @param mixed $plugin_definition
+   *   The plugin implementation definition.
+   * @param \Drupal\block\BlockRepositoryInterface $block_repository
+   *   The block repository.
+   * @param \Drupal\Core\Entity\EntityViewBuilderInterface $block_view_builder
+   *   The block view builder.
+   * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $dispatcher
+   *   The event dispatcher.
+   * @param string[] $block_list_cache_tags
+   *   The Block entity type list cache tags.
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, BlockRepositoryInterface $block_repository, EntityViewBuilderInterface $block_view_builder, EventDispatcherInterface $dispatcher, array $block_list_cache_tags) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition);
+    $this->blockRepository = $block_repository;
+    $this->blockViewBuilder = $block_view_builder;
+    $this->dispatcher = $dispatcher;
+    $this->blockListCacheTags = $block_list_cache_tags;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    return new static(
+      $configuration,
+      $plugin_id,
+      $plugin_definition,
+      $container->get('block.repository'),
+      $container->get('entity.manager')->getViewBuilder('block'),
+      $container->get('event_dispatcher'),
+      $container->get('entity.manager')->getDefinition('block')->getListCacheTags()
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setMainContent(array $main_content) {
+    $this->mainContent = $main_content;
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function build() {
+    // Track whether blocks showing the main content and messages are displayed.
+    $main_content_block_displayed = FALSE;
+    $messages_block_displayed = FALSE;
+
+    $build = [
+      '#cache' => [
+        'tags' => $this->blockListCacheTags,
+      ],
+    ];
+    $contexts = $this->getActiveBlockContexts();
+    // Load all region content assigned via blocks.
+    foreach ($this->blockRepository->getVisibleBlocksPerRegion($contexts) as $region => $blocks) {
+      /** @var $blocks \Drupal\block\BlockInterface[] */
+      foreach ($blocks as $key => $block) {
+        $block_plugin = $block->getPlugin();
+        if ($block_plugin instanceof MainContentBlockPluginInterface) {
+          $block_plugin->setMainContent($this->mainContent);
+          $main_content_block_displayed = TRUE;
+        }
+        elseif ($block_plugin instanceof MessagesBlockPluginInterface) {
+          $messages_block_displayed = TRUE;
+        }
+        $build[$region][$key] = $this->blockViewBuilder->view($block);
+
+        // The main content block cannot be cached: it is a placeholder for the
+        // render array returned by the controller. It should be rendered as-is,
+        // with other placed blocks "decorating" it.
+        if ($block_plugin instanceof MainContentBlockPluginInterface) {
+          unset($build[$region][$key]['#cache']['keys']);
+        }
+      }
+      if (!empty($build[$region])) {
+        // \Drupal\block\BlockRepositoryInterface::getVisibleBlocksPerRegion()
+        // returns the blocks in sorted order.
+        $build[$region]['#sorted'] = TRUE;
+      }
+    }
+
+    // If no block that shows the main content is displayed, still show the main
+    // content. Otherwise the end user will see all displayed blocks, but not
+    // the main content they came for.
+    if (!$main_content_block_displayed) {
+      $build['content']['system_main'] = $this->mainContent;
+    }
+
+    // If no block displays status messages, still render them.
+    if (!$messages_block_displayed) {
+      $build['content']['messages'] = [
+        '#weight' => -1000,
+        '#type' => 'status_messages',
+      ];
+    }
+
+    return $build;
+  }
+
+  /**
+   * Returns an array of context objects to set on the blocks.
+   *
+   * @return \Drupal\Component\Plugin\Context\ContextInterface[]
+   *   An array of contexts to set on the blocks.
+   */
+  protected function getActiveBlockContexts() {
+    return $this->dispatcher->dispatch(BlockEvents::ACTIVE_CONTEXT, new BlockContextEvent())->getContexts();
+  }
+
+}