Issue #2228093 by dawehner | sun: Modernize theme initialization.

core/config/install/core.extension.yml

 module: {}
-theme: {}
+theme:
+  stark: 0
 disabled:
   theme: {}

core/core.services.yml

@@ -147,7 +147,7 @@ services:
     arguments: [default]
   form_builder:
     class: Drupal\Core\Form\FormBuilder
-    arguments: ['@form_validator', '@form_submitter', '@module_handler', '@keyvalue.expirable', '@event_dispatcher', '@request_stack', '@class_resolver', '@?csrf_token', '@?http_kernel']
+    arguments: ['@form_validator', '@form_submitter', '@module_handler', '@keyvalue.expirable', '@event_dispatcher', '@request_stack', '@class_resolver', '@theme.manager', '@?csrf_token', '@?http_kernel']
   form_validator:
     class: Drupal\Core\Form\FormValidator
     arguments: ['@request_stack', '@string_translation', '@csrf_token', '@logger.channel.form']
@@ -235,10 +235,6 @@ services:
     arguments: ['@access_check.theme']
     tags:
       - { name: service_collector, tag: theme_negotiator, call: addNegotiator }
-  theme.negotiator.request_subscriber:
-    class: Drupal\Core\EventSubscriber\ThemeNegotiatorRequestSubscriber
-    tags:
-      - { name: event_subscriber }
   theme.negotiator.default:
     class: Drupal\Core\Theme\DefaultNegotiator
     arguments: ['@config.factory']
@@ -858,6 +854,12 @@ services:
     class: Zend\Feed\Writer\Extension\Threading\Renderer\Entry
   feed.writer.wellformedwebrendererentry:
     class: Zend\Feed\Writer\Extension\WellFormedWeb\Renderer\Entry
+  theme.manager:
+    class: Drupal\Core\Theme\ThemeManager
+    arguments: ['@theme_handler', '@theme.registry', '@theme.negotiator', '@theme.initialization', '@request_stack']
+  theme.initialization:
+    class: Drupal\Core\Theme\ThemeInitialization
+    arguments: ['@theme_handler', '@state']
   theme.registry:
     class: Drupal\Core\Theme\Registry
     arguments: ['@cache.default', '@lock', '@module_handler']

core/includes/common.inc

@@ -1164,8 +1164,22 @@ function _drupal_add_css($data = NULL, $options = NULL) {
  *
  * @see _drupal_add_css()
  */
-function drupal_get_css($css = NULL, $skip_alter = FALSE) {
-  global $theme_info;
+function drupal_get_css($css = NULL, $skip_alter = FALSE, $theme_add_css = TRUE) {
+  $theme_info = \Drupal::theme()->getActiveTheme();
+
+  // @todo There is probably a better place to add the CSS from themes,
+  //   see https://www.drupal.org/node/2322617.
+  if ($theme_add_css) {
+    foreach ($theme_info->getStyleSheets() as $media => $stylesheets) {
+      foreach ($stylesheets as $stylesheet) {
+        _drupal_add_css($stylesheet, array(
+          'group' => CSS_AGGREGATE_THEME,
+          'every_page' => TRUE,
+          'media' => $media
+        ));
+      }
+    }
+  }
 
   if (!isset($css)) {
     $css = _drupal_add_css();
@@ -1174,24 +1188,25 @@ function drupal_get_css($css = NULL, $skip_alter = FALSE) {
   // Allow modules and themes to alter the CSS items.
   if (!$skip_alter) {
     \Drupal::moduleHandler()->alter('css', $css);
+    \Drupal::theme()->alter('css', $css);
   }
 
   // Sort CSS items, so that they appear in the correct order.
   uasort($css, 'drupal_sort_css_js');
 
   // Allow themes to remove CSS files by basename.
-  if (!empty($theme_info->stylesheets_remove)) {
+  if ($stylesheet_remove = $theme_info->getStyleSheetsRemove()) {
     foreach ($css as $key => $options) {
-      if (isset($options['basename']) && isset($theme_info->stylesheets_remove[$options['basename']])) {
+      if (isset($options['basename']) && isset($stylesheet_remove[$options['basename']])) {
         unset($css[$key]);
       }
     }
   }
   // Allow themes to conditionally override CSS files by basename.
-  if (!empty($theme_info->stylesheets_override)) {
+  if ($stylesheet_override = $theme_info->getStyleSheetsOverride()) {
     foreach ($css as $key => $options) {
-      if (isset($options['basename']) && isset($theme_info->stylesheets_override[$options['basename']])) {
-        $css[$key]['data'] = $theme_info->stylesheets_override[$options['basename']];
+      if (isset($options['basename']) && isset($stylesheet_override[$options['basename']])) {
+        $css[$key]['data'] = $stylesheet_override[$options['basename']];
       }
     }
   }
@@ -1812,7 +1827,17 @@ function drupal_js_defaults($data = NULL) {
  * @see locale_js_alter()
  * @see drupal_js_defaults()
  */
-function drupal_get_js($scope = 'header', $javascript = NULL, $skip_alter = FALSE, $is_ajax = FALSE) {
+function drupal_get_js($scope = 'header', $javascript = NULL, $skip_alter = FALSE, $is_ajax = FALSE, $theme_add_js = TRUE) {
+  // @todo There is probably a better place to add the JS from themes,
+  //   see https://www.drupal.org/node/2322617.
+  $active_theme = \Drupal::theme()->getActiveTheme();
+  if ($theme_add_js) {
+    // Add libraries used by this theme.
+    foreach ($active_theme->getLibraries() as $library) {
+      _drupal_add_library($library);
+    }
+  }
+
   if (!isset($javascript)) {
     $javascript = _drupal_add_js();
   }
@@ -1823,6 +1848,7 @@ function drupal_get_js($scope = 'header', $javascript = NULL, $skip_alter = FALS
   // Allow modules to alter the JavaScript.
   if (!$skip_alter) {
     \Drupal::moduleHandler()->alter('js', $javascript);
+    \Drupal::theme()->alter('js', $javascript);
   }
 
   // Filter out elements of the given scope.
@@ -1839,7 +1865,7 @@ function drupal_get_js($scope = 'header', $javascript = NULL, $skip_alter = FALS
     // Don't add settings if there is no other JavaScript on the page, unless
     // this is an AJAX request.
     if (!empty($items['settings']) || $is_ajax) {
-      global $theme_key;
+      $theme_key = $active_theme->getName();
       // Provide the page with information about the theme that's used, so that
       // a later AJAX request can be rendered using the same theme.
       // @see \Drupal\Core\Theme\AjaxBasePageNegotiator
@@ -2832,6 +2858,7 @@ function drupal_prepare_page($page) {
   // Modules alter the $page as needed. Blocks are populated into regions like
   // 'sidebar_first', 'footer', etc.
   \Drupal::moduleHandler()->alter('page', $page);
+  \Drupal::theme()->alter('page', $page);
 
   // The "main" and "secondary" menus are never part of the page-level render
   // array and therefore their cache tags will never bubble up into the page
@@ -3945,7 +3972,7 @@ function drupal_flush_all_caches() {
   // use it. Unlike regular usages of this function, the installer and update
   // scripts need to flush all caches during GET requests/page building.
   if (function_exists('_drupal_maintenance_theme')) {
-    unset($GLOBALS['theme']);
+    \Drupal::theme()->resetActiveTheme();
     drupal_maintenance_theme();
   }
 }

core/includes/errors.inc

@@ -119,17 +119,18 @@ function error_displayable($error = NULL) {
 function _drupal_log_error($error, $fatal = FALSE) {
   $is_installer = drupal_installation_attempted();
   // Initialize a maintenance theme if the bootstrap was not complete.
-  // Do it early because drupal_set_message() triggers a drupal_theme_initialize().
+  // Do it early because drupal_set_message() triggers a
+  // \Drupal\Core\Theme\ThemeManager::initTheme().
   if ($fatal && drupal_get_bootstrap_phase() < DRUPAL_BOOTSTRAP_CODE) {
     // The installer initializes a maintenance theme at the earliest possible
     // point in time already. Do not unset that.
     if (!$is_installer) {
-      unset($GLOBALS['theme']);
+      \Drupal::theme()->setActiveTheme(NULL);
     }
     if (!defined('MAINTENANCE_MODE')) {
       define('MAINTENANCE_MODE', 'error');
     }
-    // No-op if $GLOBALS['theme'] is set already.
+    // No-op if the active theme is set already.
     drupal_maintenance_theme();
   }
 

core/includes/form.inc

@@ -2915,8 +2915,6 @@ function batch_set($batch_definition) {
 function batch_process($redirect = NULL, $url = 'batch', $redirect_callback = NULL) {
   $batch =& batch_get();
 
-  drupal_theme_initialize();
-
   if (isset($batch)) {
     // Add process information
     $process_info = array(
@@ -2926,7 +2924,7 @@ function batch_process($redirect = NULL, $url = 'batch', $redirect_callback = NU
       'url_options' => array(),
       'source_url' => current_path(),
       'batch_redirect' => $redirect,
-      'theme' => $GLOBALS['theme_key'],
+      'theme' => \Drupal::theme()->getActiveTheme()->getName(),
       'redirect_callback' => $redirect_callback,
     );
     $batch += $process_info;

core/includes/theme.maintenance.inc

@@ -18,10 +18,8 @@
  * setting a "maintenance_theme" key in the $settings variable in settings.php.
  */
 function _drupal_maintenance_theme() {
-  global $theme, $theme_key;
-
-  // If $theme is already set, assume the others are set too, and do nothing.
-  if (isset($theme)) {
+  // If the theme is already set, assume the others are set too, and do nothing.
+  if (\Drupal::theme()->hasActiveTheme()) {
     return;
   }
 
@@ -76,21 +74,21 @@ function _drupal_maintenance_theme() {
 
   // If no themes are installed yet, or if the requested custom theme is not
   // installed, retrieve all available themes.
+  /** @var \Drupal\Core\Theme\ThemeInitialization $theme_init */
+  $theme_init = \Drupal::service('theme.initialization');
   if (empty($themes) || !isset($themes[$custom_theme])) {
     $theme_handler = \Drupal::service('theme_handler');
     $themes = $theme_handler->rebuildThemeData();
     $theme_handler->addTheme($themes[$custom_theme]);
+    \Drupal::theme()->setActiveTheme($theme_init->getActiveTheme($themes[$custom_theme], array()));
   }
 
   // list_themes() triggers a \Drupal\Core\Extension\ModuleHandler::alter() in
   // maintenance mode, but we can't let themes alter the .info.yml data until
-  // we know a theme's base themes. So don't set global $theme until after
+  // we know a theme's base themes. So don't set active theme until after
   // list_themes() builds its cache.
   $theme = $custom_theme;
 
-  // Store the identifier for retrieving theme settings with.
-  $theme_key = $theme;
-
   // Find all our ancestor themes and put them in an array.
   $base_theme = array();
   $ancestor = $theme;
@@ -98,9 +96,10 @@ function _drupal_maintenance_theme() {
     $base_theme[] = $new_base_theme = $themes[$themes[$ancestor]->base_theme];
     $ancestor = $themes[$ancestor]->base_theme;
   }
-  _drupal_theme_initialize($themes[$theme], array_reverse($base_theme));
+  // @todo This is just a workaround. Find a better way how to handle themes
+  //   on maintenance pages, see https://www.drupal.org/node/2322619.
+  \Drupal::theme()->setActiveTheme($theme_init->getActiveTheme($themes[$custom_theme], array_reverse($base_theme)));
   // Prime the theme registry.
-  // @todo Remove global theme variables.
   Drupal::service('theme.registry');
 }
 

core/lib/Drupal.php

@@ -623,6 +623,15 @@ public static function formBuilder() {
     return static::$container->get('form_builder');
   }
 
+  /**
+   * Gets the theme service.
+   *
+   * @return \Drupal\Core\Theme\ThemeManagerInterface
+   */
+  public static function theme() {
+    return static::$container->get('theme.manager');
+  }
+
   /**
    * Gets the syncing state.
    *

core/lib/Drupal/Core/EventSubscriber/ThemeNegotiatorRequestSubscriber.php

-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\EventSubscriber\ThemeNegotiatorRequestSubscriber.
- */
-
-namespace Drupal\Core\EventSubscriber;
-
-use Drupal\Core\Routing\RouteMatch;
-use Symfony\Component\HttpKernel\HttpKernelInterface;
-use Symfony\Component\HttpKernel\KernelEvents;
-use Symfony\Component\HttpKernel\Event\GetResponseEvent;
-use Symfony\Component\EventDispatcher\EventSubscriberInterface;
-
-/**
- * Initializes the theme for the current request.
- */
-class ThemeNegotiatorRequestSubscriber implements EventSubscriberInterface {
-
-  /**
-   * Initializes the theme system after the routing system.
-   *
-   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
-   *   The Event to process.
-   */
-  public function onKernelRequestThemeNegotiator(GetResponseEvent $event) {
-    if ($event->getRequestType() == HttpKernelInterface::MASTER_REQUEST) {
-      if (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update') {
-        // @todo Refactor drupal_theme_initialize() into a request subscriber.
-        // @see https://drupal.org/node/2228093
-        drupal_theme_initialize(RouteMatch::createFromRequest($event->getRequest()));
-      }
-    }
-  }
-
-  /**
-   * Registers the methods in this class that should be listeners.
-   *
-   * @return array
-   *   An array of event listener definitions.
-   */
-  public static function getSubscribedEvents() {
-    $events[KernelEvents::REQUEST][] = array('onKernelRequestThemeNegotiator', 29);
-    return $events;
-  }
-
-}

core/lib/Drupal/Core/Extension/ModuleHandler.php

@@ -482,30 +482,6 @@ public function alter($type, &$data, &$context1 = NULL, &$context2 = NULL) {
           }
         }
       }
-      // Allow the theme to alter variables after the theme system has been
-      // initialized.
-      global $theme, $base_theme_info;
-      if (isset($theme)) {
-        $theme_keys = array();
-        foreach ($base_theme_info as $base) {
-          $theme_keys[] = $base->getName();
-        }
-        $theme_keys[] = $theme;
-        foreach ($theme_keys as $theme_key) {
-          $function = $theme_key . '_' . $hook;
-          if (function_exists($function)) {
-            $this->alterFunctions[$cid][] = $function;
-          }
-          if (isset($extra_types)) {
-            foreach ($extra_types as $extra_type) {
-              $function = $theme_key . '_' . $extra_type . '_alter';
-              if (function_exists($function)) {
-                $this->alterFunctions[$cid][] = $function;
-              }
-            }
-          }
-        }
-      }
     }
 
     foreach ($this->alterFunctions[$cid] as $function) {

core/lib/Drupal/Core/Extension/ThemeHandler.php

@@ -358,6 +358,13 @@ public function listInfo() {
     if (!isset($this->list)) {
       $this->list = array();
       $themes = $this->systemThemeList();
+      // @todo Ensure that systemThemeList() does not contain an empty list
+      //   during the batch installer, see https://www.drupal.org/node/2322619.
+      if (empty($themes)) {
+        $this->refreshInfo();
+        $this->list = $this->list ?: array();
+        $themes = \Drupal::state()->get('system.theme.data', array());
+      }
       foreach ($themes as $theme) {
         $this->addTheme($theme);
       }
@@ -393,7 +400,7 @@ public function addTheme(Extension $theme) {
   public function refreshInfo() {
     $this->reset();
     $extension_config = $this->configFactory->get('core.extension');
-    $enabled = $extension_config->get('theme') ?: array();
+    $enabled = $extension_config->get('theme');
 
     // @todo Avoid re-scanning all themes by retaining the original (unaltered)
     //   theme info somewhere.

core/lib/Drupal/Core/Form/FormBuilder.php

@@ -18,6 +18,7 @@
 use Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface;
 use Drupal\Core\Render\Element;
 use Drupal\Core\Site\Settings;
+use Drupal\Core\Theme\ThemeManagerInterface;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\HttpFoundation\RequestStack;
 use Symfony\Component\HttpFoundation\Response;
@@ -89,6 +90,13 @@ class FormBuilder implements FormBuilderInterface, FormValidatorInterface, FormS
    */
   protected $currentUser;
 
+  /**
+   * The theme manager.
+   *
+   * @var \Drupal\Core\Theme\ThemeManagerInterface
+   */
+  protected $themeManager;
+
   /**
    * @var \Drupal\Core\Form\FormValidatorInterface
    */
@@ -116,12 +124,14 @@ class FormBuilder implements FormBuilderInterface, FormValidatorInterface, FormS
    *   The request stack.
    * @param \Drupal\Core\DependencyInjection\ClassResolverInterface $class_resolver
    *   The class resolver.
+   * @param \Drupal\Core\Theme\ThemeManagerInterface $theme_manager
+   *   The theme manager.
    * @param \Drupal\Core\Access\CsrfTokenGenerator $csrf_token
    *   The CSRF token generator.
    * @param \Drupal\Core\HttpKernel $http_kernel
    *   The HTTP kernel.
    */
-  public function __construct(FormValidatorInterface $form_validator, FormSubmitterInterface $form_submitter, ModuleHandlerInterface $module_handler, KeyValueExpirableFactoryInterface $key_value_expirable_factory, EventDispatcherInterface $event_dispatcher, RequestStack $request_stack, ClassResolverInterface $class_resolver, CsrfTokenGenerator $csrf_token = NULL, HttpKernel $http_kernel = NULL) {
+  public function __construct(FormValidatorInterface $form_validator, FormSubmitterInterface $form_submitter, ModuleHandlerInterface $module_handler, KeyValueExpirableFactoryInterface $key_value_expirable_factory, EventDispatcherInterface $event_dispatcher, RequestStack $request_stack, ClassResolverInterface $class_resolver, ThemeManagerInterface $theme_manager, CsrfTokenGenerator $csrf_token = NULL, HttpKernel $http_kernel = NULL) {
     $this->formValidator = $form_validator;
     $this->formSubmitter = $form_submitter;
     $this->moduleHandler = $module_handler;
@@ -131,6 +141,7 @@ public function __construct(FormValidatorInterface $form_validator, FormSubmitte
     $this->classResolver = $class_resolver;
     $this->csrfToken = $csrf_token;
     $this->httpKernel = $http_kernel;
+    $this->themeManager = $theme_manager;
   }
 
   /**
@@ -648,6 +659,7 @@ public function prepareForm($form_id, &$form, FormStateInterface &$form_state) {
     }
     $hooks[] = 'form_' . $form_id;
     $this->moduleHandler->alter($hooks, $form, $form_state, $form_id);
+    $this->themeManager->alter($hooks, $form, $form_state, $form_id);
   }
 
   /**

core/lib/Drupal/Core/Theme/ActiveTheme.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Theme\ActiveTheme.
+ */
+
+namespace Drupal\Core\Theme;
+
+/**
+ * Defines a theme and its information needed at runtime.
+ *
+ * The theme manager will store the active theme object.
+ *
+ * @see \Drupal\Core\Theme\ThemeManager
+ * @see \Drupal\Core\Theme\ThemeInitialization
+ */
+class ActiveTheme {
+
+  /**
+   * The machine name of the active theme.
+   *
+   * @var string
+   */
+  protected $name;
+
+  /**
+   * The path to the theme.
+   *
+   * @var string
+   */
+  protected $path;
+
+  /**
+   * The engine of the theme.
+   *
+   * @var string
+   */
+  protected $engine;
+
+  /**
+   * The path to the theme engine for root themes.
+   *
+   * @var string
+   */
+  protected $owner;
+
+  /**
+   * An array of base theme active theme objects keyed by name.
+   *
+   * @var static[]
+   */
+  protected $baseThemes;
+
+  /**
+   * The extension object.
+   *
+   * @var \Drupal\Core\Extension\Extension
+   */
+  protected $extension;
+
+  /**
+   * The provided stylesheet of the theme.
+   *
+   * @var array
+   */
+  protected $styleSheets;
+
+  /**
+   * The stylesheets which are set to be removed by the theme.
+   *
+   * @var array
+   */
+  protected $styleSheetsRemove;
+
+  /**
+   * The stylesheets which are overridden by the theme.
+   *
+   * @var array
+   */
+  protected $styleSheetsOverride;
+
+  /**
+   * The libraries provided by the theme.
+   *
+   * @var array
+   */
+  protected $libraries;
+
+  /**
+   * Constructs an ActiveTheme object.
+   *
+   * @param array $values
+   *   The properties of the object, keyed by the names.
+   */
+  public function __construct(array $values) {
+    $this->name = $values['name'];
+    $this->path = $values['path'];
+    $this->engine = $values['engine'];
+    $this->owner = $values['owner'];
+    $this->styleSheets = $values['stylesheets'];
+    $this->styleSheetsRemove = $values['stylesheets_remove'];
+    $this->styleSheetsOverride = $values['stylesheets_override'];
+    $this->libraries = $values['libraries'];
+    $this->extension = $values['extension'];
+    $this->baseThemes = $values['base_themes'];
+  }
+
+  /**
+   * Returns the machine name of the theme.
+   *
+   * @return string
+   */
+  public function getName() {
+    return $this->name;
+  }
+
+  /**
+   * Returns the path to the theme directory.
+   *
+   * @return string
+   */
+  public function getPath() {
+    return $this->path;
+  }
+
+  /**
+   * Returns the theme engine.
+   *
+   * @return string
+   */
+  public function getEngine() {
+    return $this->engine;
+  }
+
+  /**
+   * Returns the path to the theme engine for root themes.
+   *
+   * @see \Drupal\Core\Extension\ThemeHandler::rebuildThemeData
+   *
+   * @return mixed
+   */
+  public function getOwner() {
+    return $this->owner;
+  }
+
+  /**
+   * Returns the extension object.
+   *
+   * @return \Drupal\Core\Extension\Extension
+   */
+  public function getExtension() {
+    return $this->extension;
+  }
+
+  /**
+   * Returns the libraries provided by the theme.
+   *
+   * @return mixed
+   */
+  public function getLibraries() {
+    return $this->libraries;
+  }
+
+  /**
+   * Returns the stylesheets provided by the theme.
+   *
+   * @return mixed
+   */
+  public function getStyleSheets() {
+    return $this->styleSheets;
+  }
+
+  /**
+   * Returns the overridden stylesheets by the theme.
+   *
+   * @return mixed
+   */
+  public function getStyleSheetsOverride() {
+    return $this->styleSheetsOverride;
+  }
+
+  /**
+   * Returns the removed stylesheets by the theme.
+   *
+   * @return mixed
+   */
+  public function getStyleSheetsRemove() {
+    return $this->styleSheetsRemove;
+  }
+
+  /**
+   * Returns an array of base theme active theme objects keyed by name.
+   *
+   * @return static[]
+   */
+  public function getBaseThemes() {
+    return $this->baseThemes;
+  }
+
+}

core/lib/Drupal/Core/Theme/DefaultNegotiator.php

@@ -43,7 +43,10 @@ public function applies(RouteMatchInterface $route_match) {
    * {@inheritdoc}
    */
   public function determineActiveTheme(RouteMatchInterface $route_match) {
-    return $this->config->get('default');
+    // @todo Find a proper way to work at the beginning of the installer when
+    //   there is no configuration available yet. One proper way could be to
+    //   provider a custom negotiator during the installer.
+    return $this->config->get('default') ?: 'stark';
   }
 
 }

core/lib/Drupal/Core/Theme/Registry.php

@@ -10,7 +10,6 @@