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<?php
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/**
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 * @file
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 * The theme system, which controls the output of Drupal.
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 *
 * The theme system allows for nearly all output of the Drupal system to be
 * customized by user themes.
 */
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use Drupal\Component\Serialization\Json;
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use Drupal\Component\Utility\SafeMarkup;
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use Drupal\Component\Utility\String;
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use Drupal\Component\Utility\Xss;
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use Drupal\Core\Config\Config;
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use Drupal\Core\Config\StorageException;
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use Drupal\Core\Extension\Extension;
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use Drupal\Core\Extension\ExtensionNameLengthException;
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use Drupal\Core\Page\FeedLinkElement;
use Drupal\Core\Page\LinkElement;
use Drupal\Core\Page\MetaElement;
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use Drupal\Core\Template\Attribute;
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use Drupal\Core\Theme\ThemeSettings;
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use Drupal\Component\Utility\NestedArray;
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use Drupal\Core\Render\Element;
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use Symfony\Component\HttpFoundation\Request;
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/**
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 * @defgroup content_flags Content markers
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 * @{
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 * Markers used by mark.html.twig and node_mark() to designate content.
 *
 * @see mark.html.twig
 * @see node_mark()
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 */
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/**
 * Mark content as read.
 */
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const MARK_READ = 0;
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/**
 * Mark content as being new.
 */
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const MARK_NEW = 1;
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/**
 * Mark content as being updated.
 */
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const MARK_UPDATED = 2;
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/**
 * A responsive table class; hide table cell on narrow devices.
 *
 * Indicates that a column has medium priority and thus can be hidden on narrow
 * width devices and shown on medium+ width devices (i.e. tablets and desktops).
 */
const RESPONSIVE_PRIORITY_MEDIUM = 'priority-medium';

/**
 * A responsive table class; only show table cell on wide devices.
 *
 * Indicates that a column has low priority and thus can be hidden on narrow
 * and medium viewports and shown on wide devices (i.e. desktops).
 */
const RESPONSIVE_PRIORITY_LOW = 'priority-low';

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/**
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 * @} End of "defgroup content_flags".
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 */

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/**
 * Determines if a theme is available to use.
 *
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 * @param string|\Drupal\Core\Extension\Extension $theme
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 *   Either the name of a theme or a full theme object.
 *
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 * @return bool
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 *   Boolean TRUE if the theme is enabled or is the site administration theme;
 *   FALSE otherwise.
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 *
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 * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
 *   Use \Drupal::service('access_check.theme')->checkAccess().
 *
 * @see \Drupal\Core\Theme\ThemeAccessCheck::checkAccess().
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 */
function drupal_theme_access($theme) {
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  if ($theme instanceof Extension) {
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    $theme = $theme->getName();
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  }
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  return \Drupal::service('access_check.theme')->checkAccess($theme);
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}

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/**
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 * Gets the theme registry.
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 *
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 * @param bool $complete
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 *   Optional boolean to indicate whether to return the complete theme registry
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 *   array or an instance of the Drupal\Core\Utility\ThemeRegistry class.
 *   If TRUE, the complete theme registry array will be returned. This is useful
 *   if you want to foreach over the whole registry, use array_* functions or
 *   inspect it in a debugger. If FALSE, an instance of the
 *   Drupal\Core\Utility\ThemeRegistry class will be returned, this provides an
 *   ArrayObject which allows it to be accessed with array syntax and isset(),
 *   and should be more lightweight than the full registry. Defaults to TRUE.
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 *
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 * @return
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 *   The complete theme registry array, or an instance of the
 *   Drupal\Core\Utility\ThemeRegistry class.
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 */
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function theme_get_registry($complete = TRUE) {
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  $theme_registry = \Drupal::service('theme.registry');
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  if ($complete) {
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    return $theme_registry->get();
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  }
  else {
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    return $theme_registry->getRuntime();
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  }
}

/**
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 * Forces the system to rebuild the theme registry.
 *
 * This function should be called when modules are added to the system, or when
 * a dynamic system needs to add more theme hooks.
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 */
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function drupal_theme_rebuild() {
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  \Drupal::service('theme.registry')->reset();
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}

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/**
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 * Returns a list of all currently available themes.
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 *
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 * Retrieved from the database, if available and the site is not in maintenance
 * mode; otherwise compiled freshly from the filesystem.
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 *
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 * @param $refresh
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 *   Whether to reload the list of themes from the database. Defaults to FALSE.
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 *
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 * @return array
 *   An associative array of the currently available themes.
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 *
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 * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
 *   Use \Drupal::service('theme_handler')->listInfo().
 *
 * @see \Drupal\Core\Extension\ThemeHandler::listInfo().
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 */
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function list_themes($refresh = FALSE) {
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  /** @var \Drupal\Core\Extension\ThemeHandler $theme_handler */
  $theme_handler = \Drupal::service('theme_handler');
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  if ($refresh) {
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    $theme_handler->reset();
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    system_list_reset();
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  }

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  return $theme_handler->listInfo();
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}

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/**
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 * Generates themed output (internal use only).
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 *
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 * _theme() is an internal function. Do not call this function directly as it
 * will prevent the following items from working correctly:
 * - Render caching.
 * - JavaScript and CSS asset attachment.
 * - Pre / post render hooks.
 * - Defaults provided by hook_element_info(), including attached assets.
 * Instead, build a render array with a #theme key, and either return the
 * array (where possible) or call drupal_render() to convert it to HTML.
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 *
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 * All requests for themed output must go through this function, which is
 * invoked as part of the @link theme_render drupal_render() process @endlink.
 * The appropriate theme function is indicated by the #theme property
 * of a renderable array. _theme() examines the request and routes it to the
 * appropriate @link themeable theme function or template @endlink, by checking
 * the theme registry.
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 *
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 * @param $hook
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 *   The name of the theme hook to call. If the name contains a
 *   double-underscore ('__') and there isn't an implementation for the full
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 *   name, the part before the '__' is checked. This allows a fallback to a
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 *   more generic implementation. For example, if _theme('links__node', ...) is
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 *   called, but there is no implementation of that theme hook, then the
 *   'links' implementation is used. This process is iterative, so if
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 *   _theme('links__contextual__node', ...) is called, _theme() checks for the
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 *   following implementations, and uses the first one that exists:
 *   - links__contextual__node
 *   - links__contextual
 *   - links
 *   This allows themes to create specific theme implementations for named
 *   objects and contexts of otherwise generic theme hooks. The $hook parameter
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 *   may also be an array, in which case the first theme hook that has an
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 *   implementation is used. This allows for the code that calls _theme() to
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 *   explicitly specify the fallback order in a situation where using the '__'
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 *   convention is not desired or is insufficient.
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 * @param $variables
 *   An associative array of variables to merge with defaults from the theme
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 *   registry, pass to preprocess functions for modification, and finally, pass
 *   to the function or template implementing the theme hook. Alternatively,
 *   this can be a renderable array, in which case, its properties are mapped to
 *   variables expected by the theme hook implementations.
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 *
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 * @return string|false
 *   An HTML string representing the themed output or FALSE if the passed $hook
 *   is not implemented.
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 *
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 * @see drupal_render()
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 * @see themeable
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 * @see hook_theme()
 * @see template_preprocess()
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 */
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function _theme($hook, $variables = array()) {
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  static $default_attributes;
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  $module_handler = \Drupal::moduleHandler();
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  $active_theme = \Drupal::theme()->getActiveTheme();
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  // If called before all modules are loaded, we do not necessarily have a full
  // theme registry to work with, and therefore cannot process the theme
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  // request properly. See also \Drupal\Core\Theme\Registry::get().
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  if (!$module_handler->isLoaded() && !defined('MAINTENANCE_MODE')) {
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    throw new Exception(t('_theme() may not be called until all modules are loaded.'));
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  }

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  /** @var \Drupal\Core\Utility\ThemeRegistry $theme_registry */
  $theme_registry = \Drupal::service('theme.registry')->getRuntime();
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  // If an array of hook candidates were passed, use the first one that has an
  // implementation.
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  if (is_array($hook)) {
    foreach ($hook as $candidate) {
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      if ($theme_registry->has($candidate)) {
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        break;
      }
    }
    $hook = $candidate;
  }
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  // Save the original theme hook, so it can be supplied to theme variable
  // preprocess callbacks.
  $original_hook = $hook;
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  // If there's no implementation, check for more generic fallbacks. If there's
  // still no implementation, log an error and return an empty string.
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  if (!$theme_registry->has($hook)) {
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    // Iteratively strip everything after the last '__' delimiter, until an
    // implementation is found.
    while ($pos = strrpos($hook, '__')) {
      $hook = substr($hook, 0, $pos);
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      if ($theme_registry->has($hook)) {
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        break;
      }
    }
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    if (!$theme_registry->has($hook)) {
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      // Only log a message when not trying theme suggestions ($hook being an
      // array).
      if (!isset($candidate)) {
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        \Drupal::logger('theme')->warning('Theme hook %hook not found.', array('%hook' => $hook));
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      }
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      // There is no theme implementation for the hook passed. Return FALSE so
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      // the function calling _theme() can differentiate between a hook that
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      // exists and renders an empty string and a hook that is not implemented.
      return FALSE;
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    }
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  }

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  $info = $theme_registry->get($hook);
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  // If a renderable array is passed as $variables, then set $variables to
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  // the arguments expected by the theme function.
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  if (isset($variables['#theme']) || isset($variables['#theme_wrappers'])) {
    $element = $variables;
    $variables = array();
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    if (isset($info['variables'])) {
      foreach (array_keys($info['variables']) as $name) {
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        if (isset($element["#$name"]) || array_key_exists("#$name", $element)) {
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          $variables[$name] = $element["#$name"];
        }
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      }
    }
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    else {
      $variables[$info['render element']] = $element;
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      // Give a hint to render engines to prevent infinite recursion.
      $variables[$info['render element']]['#render_children'] = TRUE;
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    }
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  }
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  // Merge in argument defaults.
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  if (!empty($info['variables'])) {
    $variables += $info['variables'];
  }
  elseif (!empty($info['render element'])) {
    $variables += array($info['render element'] => array());
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  }
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  // Supply original caller info.
  $variables += array(
    'theme_hook_original' => $original_hook,
  );
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  // Set base hook for later use. For example if '#theme' => 'node__article'
  // is called, we run hook_theme_suggestions_node_alter() rather than
  // hook_theme_suggestions_node__article_alter(), and also pass in the base
  // hook as the last parameter to the suggestions alter hooks.
  if (isset($info['base hook'])) {
    $base_theme_hook = $info['base hook'];
  }
  else {
    $base_theme_hook = $hook;
  }

  // Invoke hook_theme_suggestions_HOOK().
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  $suggestions = $module_handler->invokeAll('theme_suggestions_' . $base_theme_hook, array($variables));
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  // If _theme() was invoked with a direct theme suggestion like
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  // '#theme' => 'node__article', add it to the suggestions array before
  // invoking suggestion alter hooks.
  if (isset($info['base hook'])) {
    $suggestions[] = $hook;
  }
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  // Invoke hook_theme_suggestions_alter() and
  // hook_theme_suggestions_HOOK_alter().
  $hooks = array(
    'theme_suggestions',
    'theme_suggestions_' . $base_theme_hook,
  );
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  $module_handler->alter($hooks, $suggestions, $variables, $base_theme_hook);
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  \Drupal::theme()->alter($hooks, $suggestions, $variables, $base_theme_hook);
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  // Check if each suggestion exists in the theme registry, and if so,
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  // use it instead of the hook that _theme() was called with. For example, a
  // function may call _theme('node', ...), but a module can add
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  // 'node__article' as a suggestion via hook_theme_suggestions_HOOK_alter(),
  // enabling a theme to have an alternate template file for article nodes.
  foreach (array_reverse($suggestions) as $suggestion) {
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    if ($theme_registry->has($suggestion)) {
      $info = $theme_registry->get($suggestion);
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      break;
    }
  }

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  // Include a file if the theme function or variable preprocessor is held
  // elsewhere.
  if (!empty($info['includes'])) {
    foreach ($info['includes'] as $include_file) {
      include_once DRUPAL_ROOT . '/' . $include_file;
    }
  }

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  // Invoke the variable preprocessors, if any.
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  if (isset($info['base hook'])) {
    $base_hook = $info['base hook'];
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    $base_hook_info = $theme_registry->get($base_hook);
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    // Include files required by the base hook, since its variable preprocessors
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    // might reside there.
    if (!empty($base_hook_info['includes'])) {
      foreach ($base_hook_info['includes'] as $include_file) {
        include_once DRUPAL_ROOT . '/' . $include_file;
      }
    }
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    // Replace the preprocess functions with those from the base hook.
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    if (isset($base_hook_info['preprocess functions'])) {
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      // Set a variable for the 'theme_hook_suggestion'. This is used to
      // maintain backwards compatibility with template engines.
      $theme_hook_suggestion = $hook;
      $info['preprocess functions'] = $base_hook_info['preprocess functions'];
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    }
  }
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  if (isset($info['preprocess functions'])) {
    foreach ($info['preprocess functions'] as $preprocessor_function) {
      if (function_exists($preprocessor_function)) {
        $preprocessor_function($variables, $hook, $info);
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      }
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    }
  }
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  // Generate the output using either a function or a template.
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  $output = '';
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  if (isset($info['function'])) {
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    if (function_exists($info['function'])) {
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      $output = SafeMarkup::set($info['function']($variables));
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    }
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  }
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  else {
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    $render_function = 'twig_render_template';
    $extension = '.html.twig';
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    // The theme engine may use a different extension and a different renderer.
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    $theme_engine = $active_theme->getEngine();
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    if (isset($theme_engine)) {
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      if ($info['type'] != 'module') {
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        if (function_exists($theme_engine . '_render_template')) {
          $render_function = $theme_engine . '_render_template';
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        }
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        $extension_function = $theme_engine . '_extension';
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        if (function_exists($extension_function)) {
          $extension = $extension_function();
        }
      }
    }

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    // In some cases, a template implementation may not have had
    // template_preprocess() run (for example, if the default implementation is
    // a function, but a template overrides that default implementation). In
    // these cases, a template should still be able to expect to have access to
    // the variables provided by template_preprocess(), so we add them here if
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    // they don't already exist. We don't want the overhead of running
    // template_preprocess() twice, so we use the 'directory' variable to
    // determine if it has already run, which while not completely intuitive,
    // is reasonably safe, and allows us to save on the overhead of adding some
    // new variable to track that.
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    if (!isset($variables['directory'])) {
      $default_template_variables = array();
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      template_preprocess($default_template_variables, $hook, $info);
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      $variables += $default_template_variables;
    }
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    if (!isset($default_attributes)) {
      $default_attributes = new Attribute();
    }
    foreach (array('attributes', 'title_attributes', 'content_attributes') as $key) {
      if (isset($variables[$key]) && !($variables[$key] instanceof Attribute)) {
        if ($variables[$key]) {
          $variables[$key] = new Attribute($variables[$key]);
        }
        else {
          // Create empty attributes.
          $variables[$key] = clone $default_attributes;
        }
      }
    }
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    // Render the output using the template file.
    $template_file = $info['template'] . $extension;
    if (isset($info['path'])) {
      $template_file = $info['path'] . '/' . $template_file;
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    }
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    // Add the theme suggestions to the variables array just before rendering
    // the template for backwards compatibility with template engines.
    $variables['theme_hook_suggestions'] = $suggestions;
    // For backwards compatibility, pass 'theme_hook_suggestion' on to the
    // template engine. This is only set when calling a direct suggestion like
    // '#theme' => 'menu_tree__shortcut_default' when the template exists in the
    // current theme.
    if (isset($theme_hook_suggestion)) {
      $variables['theme_hook_suggestion'] = $theme_hook_suggestion;
    }
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    $output = $render_function($template_file, $variables);
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  }
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  return (string) $output;
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}

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/**
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 * Allows themes and/or theme engines to discover overridden theme functions.
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 *
 * @param $cache
 *   The existing cache of theme hooks to test against.
 * @param $prefixes
 *   An array of prefixes to test, in reverse order of importance.
 *
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 * @return $implementations
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 *   The functions found, suitable for returning from hook_theme;
 */
function drupal_find_theme_functions($cache, $prefixes) {
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  $implementations = array();
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  $functions = get_defined_functions();

  foreach ($cache as $hook => $info) {
    foreach ($prefixes as $prefix) {
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      // Find theme functions that implement possible "suggestion" variants of
      // registered theme hooks and add those as new registered theme hooks.
      // The 'pattern' key defines a common prefix that all suggestions must
      // start with. The default is the name of the hook followed by '__'. An
      // 'base hook' key is added to each entry made for a found suggestion,
      // so that common functionality can be implemented for all suggestions of
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      // the same base hook. To keep things simple, deep hierarchy of
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      // suggestions is not supported: each suggestion's 'base hook' key
      // refers to a base hook, not to another suggestion, and all suggestions
      // are found using the base hook's pattern, not a pattern from an
      // intermediary suggestion.
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      $pattern = isset($info['pattern']) ? $info['pattern'] : ($hook . '__');
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      if (!isset($info['base hook']) && !empty($pattern)) {
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        $matches = preg_grep('/^' . $prefix . '_' . $pattern . '/', $functions['user']);
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        if ($matches) {
          foreach ($matches as $match) {
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            $new_hook = substr($match, strlen($prefix) + 1);
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            $arg_name = isset($info['variables']) ? 'variables' : 'render element';
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            $implementations[$new_hook] = array(
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              'function' => $match,
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              $arg_name => $info[$arg_name],
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              'base hook' => $hook,
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            );
          }
        }
      }
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      // Find theme functions that implement registered theme hooks and include
      // that in what is returned so that the registry knows that the theme has
      // this implementation.
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      if (function_exists($prefix . '_' . $hook)) {
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        $implementations[$hook] = array(
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          'function' => $prefix . '_' . $hook,
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        );
      }
    }
  }

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  return $implementations;
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}

/**
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 * Allows themes and/or theme engines to easily discover overridden templates.
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 *
 * @param $cache
 *   The existing cache of theme hooks to test against.
 * @param $extension
 *   The extension that these templates will have.
 * @param $path
 *   The path to search.
 */
function drupal_find_theme_templates($cache, $extension, $path) {
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  $implementations = array();
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  // Collect paths to all sub-themes grouped by base themes. These will be
  // used for filtering. This allows base themes to have sub-themes in its
  // folder hierarchy without affecting the base themes template discovery.
  $theme_paths = array();
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  foreach (list_themes() as $theme_info) {
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    if (!empty($theme_info->base_theme)) {
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      $theme_paths[$theme_info->base_theme][$theme_info->getName()] = $theme_info->getPath();
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    }
  }
  foreach ($theme_paths as $basetheme => $subthemes) {
    foreach ($subthemes as $subtheme => $subtheme_path) {
      if (isset($theme_paths[$subtheme])) {
        $theme_paths[$basetheme] = array_merge($theme_paths[$basetheme], $theme_paths[$subtheme]);
      }
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    }
  }
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  $theme = \Drupal::theme()->getActiveTheme()->getName();
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  $subtheme_paths = isset($theme_paths[$theme]) ? $theme_paths[$theme] : array();
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  // Escape the periods in the extension.
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  $regex = '/' . str_replace('.', '\.', $extension) . '$/';
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  // Get a listing of all template files in the path to search.
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  $files = file_scan_directory($path, $regex, array('key' => 'filename'));
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  // Find templates that implement registered theme hooks and include that in
  // what is returned so that the registry knows that the theme has this
  // implementation.
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  foreach ($files as $template => $file) {
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    // Ignore sub-theme templates for the current theme.
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    if (strpos($file->uri, str_replace($subtheme_paths, '', $file->uri)) !== 0) {
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      continue;
    }
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    // Remove the extension from the filename.
    $template = str_replace($extension, '', $template);
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    // Transform - in filenames to _ to match function naming scheme
    // for the purposes of searching.
    $hook = strtr($template, '-', '_');
    if (isset($cache[$hook])) {
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      $implementations[$hook] = array(
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        'template' => $template,
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        'path' => dirname($file->uri),
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      );
    }
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    // Match templates based on the 'template' filename.
    foreach ($cache as $hook => $info) {
      if (isset($info['template'])) {
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        $template_candidates = array($info['template'], str_replace($info['theme path'] . '/templates/', '', $info['template']));
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        if (in_array($template, $template_candidates)) {
          $implementations[$hook] = array(
            'template' => $template,
            'path' => dirname($file->uri),
          );
        }
      }
    }
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  }

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  // Find templates that implement possible "suggestion" variants of registered
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  // theme hooks and add those as new registered theme hooks. See
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  // drupal_find_theme_functions() for more information about suggestions and
  // the use of 'pattern' and 'base hook'.
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  $patterns = array_keys($files);
  foreach ($cache as $hook => $info) {
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    $pattern = isset($info['pattern']) ? $info['pattern'] : ($hook . '__');
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    if (!isset($info['base hook']) && !empty($pattern)) {
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      // Transform _ in pattern to - to match file naming scheme
      // for the purposes of searching.
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      $pattern = strtr($pattern, '_', '-');
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      $matches = preg_grep('/^' . $pattern . '/', $patterns);
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      if ($matches) {
        foreach ($matches as $match) {
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          $file = $match;
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          // Remove the extension from the filename.
          $file = str_replace($extension, '', $file);
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          // Put the underscores back in for the hook name and register this
          // pattern.
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          $arg_name = isset($info['variables']) ? 'variables' : 'render element';
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          $implementations[strtr($file, '-', '_')] = array(
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            'template' => $file,
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            'path' => dirname($files[$match]->uri),
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            $arg_name => $info[$arg_name],
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            'base hook' => $hook,
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          );
        }
      }
    }
  }
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  return $implementations;
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}

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/**
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 * Retrieves a setting for the current theme or for a given theme.
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 *
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 * The final setting is obtained from the last value found in the following
 * sources:
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 * - the default theme-specific settings defined in any base theme's .info.yml
 *   file
 * - the default theme-specific settings defined in the theme's .info.yml file
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 * - the saved values from the global theme settings form
 * - the saved values from the theme's settings form
 * To only retrieve the default global theme setting, an empty string should be
 * given for $theme.
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 *
 * @param $setting_name
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 *   The name of the setting to be retrieved.
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 * @param $theme
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 *   The name of a given theme; defaults to the current theme.
 *
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 * @return
 *   The value of the requested setting, NULL if the setting does not exist.
 */
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function theme_get_setting($setting_name, $theme = NULL) {
  $cache = &drupal_static(__FUNCTION__, array());
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  // If no key is given, use the current theme if we can determine it.
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  if (!isset($theme)) {
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    $theme = \Drupal::theme()->getActiveTheme()->getName();
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  }
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  if (empty($cache[$theme])) {
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    // Create a theme settings object.
    $cache[$theme] = new ThemeSettings($theme);
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    // Get the values for the theme-specific settings from the .info.yml files
    // of the theme and all its base themes.
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    $themes = list_themes();
    if ($theme && isset($themes[$theme])) {
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      $theme_object = $themes[$theme];

      // Create a list which includes the current theme and all its base themes.
      if (isset($theme_object->base_themes)) {
        $theme_keys = array_keys($theme_object->base_themes);
        $theme_keys[] = $theme;
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      }
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      else {
        $theme_keys = array($theme);
      }
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      // Read hard-coded default settings from the theme info files.
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      foreach ($theme_keys as $theme_key) {
        if (!empty($themes[$theme_key]->info['settings'])) {
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          $cache[$theme]->merge($themes[$theme_key]->info['settings']);
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        }
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      }
    }

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    // Get the global settings from configuration.
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    $cache[$theme]->merge(\Drupal::config('system.theme.global')->get());
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    if ($theme && isset($themes[$theme])) {
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      // Retrieve configured theme-specific settings, if any.
      try {
        if ($theme_settings = \Drupal::config($theme . '.settings')->get()) {
          $cache[$theme]->merge($theme_settings);
        }
      }
      catch (StorageException $e) {
      }
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      // If the theme does not support a particular feature, override the global
      // setting and set the value to NULL.
      if (!empty($theme_object->info['features'])) {
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        foreach (_system_default_theme_features() as $feature) {
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          if (!in_array($feature, $theme_object->info['features'])) {
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            $cache[$theme]->set('features.' . $feature, NULL);
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          }
        }
      }

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      // Generate the path to the logo image.
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      if ($cache[$theme]->get('features.logo')) {
        $logo_path = $cache[$theme]->get('logo.path');
        if ($cache[$theme]->get('logo.use_default')) {
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          $cache[$theme]->set('logo.url', file_create_url($theme_object->getPath() . '/logo.png'));
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        }
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        elseif ($logo_path) {
          $cache[$theme]->set('logo.url', file_create_url($logo_path));
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        }
      }
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      // Generate the path to the favicon.
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      if ($cache[$theme]->get('features.favicon')) {
        $favicon_path = $cache[$theme]->get('favicon.path');
        if ($cache[$theme]->get('favicon.use_default')) {
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          if (file_exists($favicon = $theme_object->getPath() . '/favicon.ico')) {
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            $cache[$theme]->set('favicon.url', file_create_url($favicon));
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          }
          else {
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            $cache[$theme]->set('favicon.url', file_create_url('core/misc/favicon.ico'));
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          }
        }
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        elseif ($favicon_path) {
          $cache[$theme]->set('favicon.url', file_create_url($favicon_path));
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        }
        else {
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          $cache[$theme]->set('features.favicon', FALSE);
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        }
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      }
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    }
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  }

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  return $cache[$theme]->get($setting_name);
}

/**
 * Converts theme settings to configuration.
 *
 * @see system_theme_settings_submit()
 *
 * @param array $theme_settings
 *   An array of theme settings from system setting form or a Drupal 7 variable.
 * @param Config $config
 *   The configuration object to update.
 *
 * @return
 *   The Config object with updated data.
 */
function theme_settings_convert_to_config(array $theme_settings, Config $config) {
  foreach ($theme_settings as $key => $value) {
    if ($key == 'default_logo') {
      $config->set('logo.use_default', $value);
    }
    else if ($key == 'logo_path') {
      $config->set('logo.path', $value);
    }
    else if ($key == 'default_favicon') {
      $config->set('favicon.use_default', $value);
    }
    else if ($key == 'favicon_path') {
      $config->set('favicon.path', $value);
    }
    else if ($key == 'favicon_mimetype') {
      $config->set('favicon.mimetype', $value);
    }
    else if (substr($key, 0, 7) == 'toggle_') {
      $config->set('features.' . drupal_substr($key, 7), $value);
    }
    else if (!in_array($key, array('theme', 'logo_upload'))) {
      $config->set($key, $value);
    }
  }
  return $config;
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}

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/**
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 * Enables a given list of themes.
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 *
 * @param $theme_list
 *   An array of theme names.
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 *
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 * @return bool
 *   Whether any of the given themes have been enabled.
 *
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 * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
 *   Use \Drupal::service('theme_handler')->enable().
 *
 * @see \Drupal\Core\Extension\ThemeHandler::enable().
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 */
function theme_enable($theme_list) {
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  return \Drupal::service('theme_handler')->enable($theme_list);
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}

/**
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 * Disables a given list of themes.
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 *
 * @param $theme_list
 *   An array of theme names.
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 *
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 * @return bool
 *   Whether any of the given themes have been disabled.
 *
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 * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
 *   Use \Drupal::service('theme_handler')->disable().
 *
 * @see \Drupal\Core\Extension\ThemeHandler::disable().
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 */
function theme_disable($theme_list) {
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  return \Drupal::service('theme_handler')->disable($theme_list);
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}

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/**
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 * @addtogroup themeable
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 * @{
 */
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/**
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 * Prepares variables for time templates.
 *
 * Default template: time.html.twig.
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 *
 * @param array $variables
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 *   An associative array possibly containing:
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 *   - attributes['timestamp']:
 *   - timestamp:
 *   - text:
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 */
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function template_preprocess_time(&$variables) {
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