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    theme.inc 91.37 KiB
    <?php
    
    /**
     * @file
     * The theme system, which controls the output of Drupal.
     *
     * The theme system allows for nearly all output of the Drupal system to be
     * customized by user themes.
     */
    
    use Drupal\Component\Utility\String;
    use Drupal\Component\Utility\UrlHelper;
    use Drupal\Core\Config\Config;
    use Drupal\Core\Language\Language;
    use Drupal\Core\Extension\Extension;
    use Drupal\Core\Extension\ExtensionNameLengthException;
    use Drupal\Core\Template\Attribute;
    use Drupal\Core\Template\RenderWrapper;
    use Drupal\Core\Theme\ThemeSettings;
    use Drupal\Component\Utility\NestedArray;
    use Drupal\Core\Render\Element;
    
    /**
     * @defgroup content_flags Content markers
     * @{
     * Markers used by theme_mark() and node_mark() to designate content.
     * @see theme_mark(), node_mark()
     */
    
    /**
     * Mark content as read.
     */
    const MARK_READ = 0;
    
    /**
     * Mark content as being new.
     */
    const MARK_NEW = 1;
    
    /**
     * Mark content as being updated.
     */
    const MARK_UPDATED = 2;
    
    /**
     * 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';
    
    /**
     * @} End of "defgroup content_flags".
     */
    
    /**
     * Determines if a theme is available to use.
     *
     * @param string|\Drupal\Core\Extension\Extension $theme
     *   Either the name of a theme or a full theme object.
     *
     * @return bool
     *   Boolean TRUE if the theme is enabled or is the site administration theme;
     *   FALSE otherwise.
     *
     * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
     *   Use \Drupal::service('access_check.theme')->checkAccess().
     *
     * @see \Drupal\Core\Theme\ThemeAccessCheck::checkAccess().
     */
    function drupal_theme_access($theme) {
      if ($theme instanceof Extension) {
        $theme = $theme->getName();
      }
      return \Drupal::service('access_check.theme')->checkAccess($theme);
    }
    
    /**
     * Initializes the theme system by loading the theme.
     */
    function drupal_theme_initialize() {
      global $theme, $theme_key;
    
      // If $theme is already set, assume the others are set, too, and do nothing
      if (isset($theme)) {
        return;
      }
    
      $themes = list_themes();
    
      // @todo Let the theme.negotiator listen to the kernel request event.
      // Determine the active theme for the theme negotiator service. This includes
      // the default theme as well as really specific ones like the ajax base theme.
      $request = \Drupal::request();
      $theme = \Drupal::service('theme.negotiator')->determineActiveTheme($request) ?: 'stark';
    
      // 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 = $theme;
      while ($ancestor && isset($themes[$ancestor]->base_theme)) {
        $ancestor = $themes[$ancestor]->base_theme;
        $base_theme[] = $themes[$ancestor];
      }
      _drupal_theme_initialize($themes[$theme], array_reverse($base_theme));
    }
    
    /**
     * Initializes the theme system given already loaded information.
     *
     * This function is useful to initialize a theme when no database is present.
     *
     * @param \Drupal\Core\Extension\Extension $theme
     *   The theme extension object.
     * @param \Drupal\Core\Extension\Extension[] $base_theme
     *    An optional array of objects that represent the 'base theme' if the
     *    theme is meant to be derivative of another theme. It requires
     *    the same information as the $theme object. It should be in
     *    'oldest first' order, meaning the top level of the chain will
     *    be first.
     */
    function _drupal_theme_initialize($theme, $base_theme = array()) {
      global $theme_info, $base_theme_info, $theme_engine, $theme_path;
      $theme_info = $theme;
      $base_theme_info = $base_theme;
    
      $theme_path = $theme->getPath();
    
      // Prepare stylesheets from this theme as well as all ancestor themes.
      // We work it this way so that we can have child themes override parent
      // theme stylesheets easily.
      $final_stylesheets = array();
      // CSS file basenames to override, pointing to the final, overridden filepath.
      $theme->stylesheets_override = array();
      // CSS file basenames to remove.
      $theme->stylesheets_remove = array();
    
      // Grab stylesheets from base theme
      foreach ($base_theme as $base) {
        if (!empty($base->stylesheets)) {
          foreach ($base->stylesheets as $media => $stylesheets) {
            foreach ($stylesheets as $name => $stylesheet) {
              $final_stylesheets[$media][$name] = $stylesheet;
            }
          }
        }
        $base_theme_path = $base->getPath();
        if (!empty($base->info['stylesheets-remove'])) {
          foreach ($base->info['stylesheets-remove'] as $basename) {
            $theme->stylesheets_remove[$basename] = $base_theme_path . '/' . $basename;
          }
        }
        if (!empty($base->info['stylesheets-override'])) {
          foreach ($base->info['stylesheets-override'] as $name) {
            $basename = drupal_basename($name);
            $theme->stylesheets_override[$basename] = $base_theme_path . '/' . $name;
          }
        }
      }
    
      // Add stylesheets used by this theme.
      if (!empty($theme->stylesheets)) {
        foreach ($theme->stylesheets as $media => $stylesheets) {
          foreach ($stylesheets as $name => $stylesheet) {
            $final_stylesheets[$media][$name] = $stylesheet;
          }
        }
      }
      if (!empty($theme->info['stylesheets-remove'])) {
        foreach ($theme->info['stylesheets-remove'] as $basename) {
          $theme->stylesheets_remove[$basename] = $theme_path . '/' . $basename;
    
          if (isset($theme->stylesheets_override[$basename])) {
            unset($theme->stylesheets_override[$basename]);
          }
        }
      }
      if (!empty($theme->info['stylesheets-override'])) {
        foreach ($theme->info['stylesheets-override'] as $name) {
          $basename = drupal_basename($name);
          $theme->stylesheets_override[$basename] = $theme_path . '/' . $name;
    
          if (isset($theme->stylesheets_remove[$basename])) {
            unset($theme->stylesheets_remove[$basename]);
          }
        }
      }
    
      // And now add the stylesheets properly.
      $css = array();
      foreach ($final_stylesheets as $media => $stylesheets) {
        foreach ($stylesheets as $stylesheet) {
          $css['#attached']['css'][$stylesheet] = array(
            'group' => CSS_AGGREGATE_THEME,
            'every_page' => TRUE,
            'media' => $media
          );
        }
      }
      drupal_render($css);
    
      // Do basically the same as the above for scripts
      $final_scripts = array();
    
      // Grab scripts from base theme
      foreach ($base_theme as $base) {
        if (!empty($base->scripts)) {
          foreach ($base->scripts as $name => $script) {
            $final_scripts[$name] = $script;
          }
        }
      }
    
      // Add scripts used by this theme.
      if (!empty($theme->scripts)) {
        foreach ($theme->scripts as $name => $script) {
          $final_scripts[$name] = $script;
        }
      }
    
      // Add scripts used by this theme.
      $js = array();
      foreach ($final_scripts as $script) {
        $js['#attached']['js'][] = array(
          'data' => $script,
          'group' => JS_THEME,
          'every_page' => TRUE,
        );
      }
      drupal_render($js);
    
      $theme_engine = NULL;
    
      // Initialize the theme.
      if (isset($theme->engine)) {
        // Include the engine.
        include_once DRUPAL_ROOT . '/' . $theme->owner;
    
        $theme_engine = $theme->engine;
        if (function_exists($theme_engine . '_init')) {
          foreach ($base_theme as $base) {
            call_user_func($theme_engine . '_init', $base);
          }
          call_user_func($theme_engine . '_init', $theme);
        }
      }
      else {
        // include non-engine theme files
        foreach ($base_theme as $base) {
          // Include the theme file or the engine.
          if (!empty($base->owner)) {
            include_once DRUPAL_ROOT . '/' . $base->owner;
          }
        }
        // and our theme gets one too.
        if (!empty($theme->owner)) {
          include_once DRUPAL_ROOT . '/' . $theme->owner;
        }
      }
    
      // Always include Twig as the default theme engine.
      include_once DRUPAL_ROOT . '/core/themes/engines/twig/twig.engine';
    }
    
    /**
     * Gets the theme registry.
     *
     * @param bool $complete
     *   Optional boolean to indicate whether to return the complete theme registry
     *   array or an instance of the Drupal\Core\Utility\ThemeRegistry class.
     *   If TRUE, the complete theme registry array will be returned. This is useful
     *   if you want to foreach over the whole registry, use array_* functions or
     *   inspect it in a debugger. If FALSE, an instance of the
     *   Drupal\Core\Utility\ThemeRegistry class will be returned, this provides an
     *   ArrayObject which allows it to be accessed with array syntax and isset(),
     *   and should be more lightweight than the full registry. Defaults to TRUE.
     *
     * @return
     *   The complete theme registry array, or an instance of the
     *   Drupal\Core\Utility\ThemeRegistry class.
     */
    function theme_get_registry($complete = TRUE) {
      $theme_registry = \Drupal::service('theme.registry');
      if ($complete) {
        return $theme_registry->get();
      }
      else {
        return $theme_registry->getRuntime();
      }
    }
    
    /**
     * 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.
     */
    function drupal_theme_rebuild() {
      \Drupal::service('theme.registry')->reset();
    }
    
    /**
     * Returns a list of all currently available themes.
     *
     * Retrieved from the database, if available and the site is not in maintenance
     * mode; otherwise compiled freshly from the filesystem.
     *
     * @param $refresh
     *   Whether to reload the list of themes from the database. Defaults to FALSE.
     *
     * @return array
     *   An associative array of the currently available themes.
     *
     * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
     *   Use \Drupal::service('theme_handler')->listInfo().
     *
     * @see \Drupal\Core\Extension\ThemeHandler::listInfo().
     */
    function list_themes($refresh = FALSE) {
      /** @var \Drupal\Core\Extension\ThemeHandler $theme_handler */
      $theme_handler = \Drupal::service('theme_handler');
    
      if ($refresh) {
        $theme_handler->reset();
        system_list_reset();
      }
    
      return $theme_handler->listInfo();
    }
    
    /**
     * Generates themed output (internal use only).
     *
     * _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.
     *
     * 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.
     *
     * @param $hook
     *   The name of the theme hook to call. If the name contains a
     *   double-underscore ('__') and there isn't an implementation for the full
     *   name, the part before the '__' is checked. This allows a fallback to a
     *   more generic implementation. For example, if _theme('links__node', ...) is
     *   called, but there is no implementation of that theme hook, then the
     *   'links' implementation is used. This process is iterative, so if
     *   _theme('links__contextual__node', ...) is called, _theme() checks for the
     *   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
     *   may also be an array, in which case the first theme hook that has an
     *   implementation is used. This allows for the code that calls _theme() to
     *   explicitly specify the fallback order in a situation where using the '__'
     *   convention is not desired or is insufficient.
     * @param $variables
     *   An associative array of variables to merge with defaults from the theme
     *   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.
     *
     * @return string|false
     *   An HTML string representing the themed output or FALSE if the passed $hook
     *   is not implemented.
     *
     * @see drupal_render()
     * @see themeable
     * @see hook_theme()
     * @see template_preprocess()
     */
    function _theme($hook, $variables = array()) {
      static $default_attributes;
      // 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
      // request properly. See also \Drupal\Core\Theme\Registry::get().
      if (!\Drupal::moduleHandler()->isLoaded() && !defined('MAINTENANCE_MODE')) {
        throw new Exception(t('_theme() may not be called until all modules are loaded.'));
      }
    
      /** @var \Drupal\Core\Utility\ThemeRegistry $theme_registry */
      $theme_registry = \Drupal::service('theme.registry')->getRuntime();
    
      // If an array of hook candidates were passed, use the first one that has an
      // implementation.
      if (is_array($hook)) {
        foreach ($hook as $candidate) {
          if ($theme_registry->has($candidate)) {
            break;
          }
        }
        $hook = $candidate;
      }
      // Save the original theme hook, so it can be supplied to theme variable
      // preprocess callbacks.
      $original_hook = $hook;
    
      // If there's no implementation, check for more generic fallbacks. If there's
      // still no implementation, log an error and return an empty string.
      if (!$theme_registry->has($hook)) {
        // Iteratively strip everything after the last '__' delimiter, until an
        // implementation is found.
        while ($pos = strrpos($hook, '__')) {
          $hook = substr($hook, 0, $pos);
          if ($theme_registry->has($hook)) {
            break;
          }
        }
        if (!$theme_registry->has($hook)) {
          // Only log a message when not trying theme suggestions ($hook being an
          // array).
          if (!isset($candidate)) {
            watchdog('theme', 'Theme hook %hook not found.', array('%hook' => $hook), WATCHDOG_WARNING);
          }
          // There is no theme implementation for the hook passed. Return FALSE so
          // the function calling _theme() can differentiate between a hook that
          // exists and renders an empty string and a hook that is not implemented.
          return FALSE;
        }
      }
    
      $info = $theme_registry->get($hook);
      global $theme_path;
      $temp = $theme_path;
      // point path_to_theme() to the currently used theme path:
      $theme_path = $info['theme path'];
    
    
      // If a renderable array is passed as $variables, then set $variables to
      // the arguments expected by the theme function.
      if (isset($variables['#theme']) || isset($variables['#theme_wrappers'])) {
        $element = $variables;
        $variables = array();
        if (isset($info['variables'])) {
          foreach (array_keys($info['variables']) as $name) {
            if (isset($element["#$name"]) || array_key_exists("#$name", $element)) {
              $variables[$name] = $element["#$name"];
            }
          }
        }
        else {
          $variables[$info['render element']] = $element;
          // Give a hint to render engines to prevent infinite recursion.
          $variables[$info['render element']]['#render_children'] = TRUE;
        }
      }
    
      // Merge in argument defaults.
      if (!empty($info['variables'])) {
        $variables += $info['variables'];
      }
      elseif (!empty($info['render element'])) {
        $variables += array($info['render element'] => array());
      }
      // Supply original caller info.
      $variables += array(
        'theme_hook_original' => $original_hook,
      );
    
      // 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().
      $suggestions = Drupal::moduleHandler()->invokeAll('theme_suggestions_' . $base_theme_hook, array($variables));
      // If _theme() was invoked with a direct theme suggestion like
      // '#theme' => 'node__article', add it to the suggestions array before
      // invoking suggestion alter hooks.
      if (isset($info['base hook'])) {
        $suggestions[] = $hook;
      }
    
      // Invoke hook_theme_suggestions_alter() and
      // hook_theme_suggestions_HOOK_alter().
      $hooks = array(
        'theme_suggestions',
        'theme_suggestions_' . $base_theme_hook,
      );
      \Drupal::moduleHandler()->alter($hooks, $suggestions, $variables, $base_theme_hook);
    
      // Check if each suggestion exists in the theme registry, and if so,
      // use it instead of the hook that _theme() was called with. For example, a
      // function may call _theme('node', ...), but a module can add
      // '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 $suggestion) {
        if ($theme_registry->has($suggestion)) {
          $info = $theme_registry->get($suggestion);
          break;
        }
      }
    
      // 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;
        }
      }
    
      // Invoke the variable preprocessors, if any.
      if (isset($info['base hook'])) {
        $base_hook = $info['base hook'];
        $base_hook_info = $theme_registry->get($base_hook);
        // Include files required by the base hook, since its variable preprocessors
        // might reside there.
        if (!empty($base_hook_info['includes'])) {
          foreach ($base_hook_info['includes'] as $include_file) {
            include_once DRUPAL_ROOT . '/' . $include_file;
          }
        }
        // Replace the preprocess functions with those from the base hook.
        if (isset($base_hook_info['preprocess functions'])) {
          // 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'] = $base_hook_info['preprocess functions'];
        }
      }
      if (isset($info['preprocess functions'])) {
        foreach ($info['preprocess functions'] as $preprocessor_function) {
          if (function_exists($preprocessor_function)) {
            $preprocessor_function($variables, $hook, $info);
          }
        }
      }
    
      // Generate the output using either a function or a template.
      $output = '';
      if (isset($info['function'])) {
        if (function_exists($info['function'])) {
          $output = $info['function']($variables);
        }
      }
      else {
        $render_function = 'twig_render_template';
        $extension = '.html.twig';
    
        // The theme engine may use a different extension and a different renderer.
        global $theme_engine;
        if (isset($theme_engine)) {
          if ($info['type'] != 'module') {
            if (function_exists($theme_engine . '_render_template')) {
              $render_function = $theme_engine . '_render_template';
            }
            $extension_function = $theme_engine . '_extension';
            if (function_exists($extension_function)) {
              $extension = $extension_function();
            }
          }
        }
    
        // 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
        // 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.
        if (!isset($variables['directory'])) {
          $default_template_variables = array();
          template_preprocess($default_template_variables, $hook, $info);
          $variables += $default_template_variables;
        }
        if (!isset($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;
            }
          }
        }
    
        // Render the output using the template file.
        $template_file = $info['template'] . $extension;
        if (isset($info['path'])) {
          $template_file = $info['path'] . '/' . $template_file;
        }
        // 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;
        }
        $output = $render_function($template_file, $variables);
      }
    
      // restore path_to_theme()
      $theme_path = $temp;
      return (string) $output;
    }
    
    /**
     * Returns the path to the current themed element.
     *
     * It can point to the active theme or the module handling a themed
     * implementation. For example, when invoked within the scope of a theming call
     * it will depend on where the theming function is handled. If implemented from
     * a module, it will point to the module. If implemented from the active theme,
     * it will point to the active theme. When called outside the scope of a
     * theming call, it will always point to the active theme.
     */
    function path_to_theme() {
      global $theme_path;
    
      if (!isset($theme_path)) {
        drupal_theme_initialize();
      }
    
      return $theme_path;
    }
    
    /**
     * Allows themes and/or theme engines to discover overridden theme functions.
     *
     * @param $cache
     *   The existing cache of theme hooks to test against.
     * @param $prefixes
     *   An array of prefixes to test, in reverse order of importance.
     *
     * @return $implementations
     *   The functions found, suitable for returning from hook_theme;
     */
    function drupal_find_theme_functions($cache, $prefixes) {
      $implementations = array();
      $functions = get_defined_functions();
    
      foreach ($cache as $hook => $info) {
        foreach ($prefixes as $prefix) {
          // 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
          // the same base hook. To keep things simple, deep hierarchy of
          // 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.
          $pattern = isset($info['pattern']) ? $info['pattern'] : ($hook . '__');
          if (!isset($info['base hook']) && !empty($pattern)) {
            $matches = preg_grep('/^' . $prefix . '_' . $pattern . '/', $functions['user']);
            if ($matches) {
              foreach ($matches as $match) {
                $new_hook = substr($match, strlen($prefix) + 1);
                $arg_name = isset($info['variables']) ? 'variables' : 'render element';
                $implementations[$new_hook] = array(
                  'function' => $match,
                  $arg_name => $info[$arg_name],
                  'base hook' => $hook,
                );
              }
            }
          }
          // Find theme functions that implement registered theme hooks and include
          // that in what is returned so that the registry knows that the theme has
          // this implementation.
          if (function_exists($prefix . '_' . $hook)) {
            $implementations[$hook] = array(
              'function' => $prefix . '_' . $hook,
            );
          }
        }
      }
    
      return $implementations;
    }
    
    /**
     * Allows themes and/or theme engines to easily discover overridden templates.
     *
     * @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) {
      $implementations = array();
    
      // 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();
      foreach (list_themes() as $theme_info) {
        if (!empty($theme_info->base_theme)) {
          $theme_paths[$theme_info->base_theme][$theme_info->getName()] = $theme_info->getPath();
        }
      }
      foreach ($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]);
          }
        }
      }
      global $theme;
      $subtheme_paths = isset($theme_paths[$theme]) ? $theme_paths[$theme] : array();
    
      // Escape the periods in the extension.
      $regex = '/' . str_replace('.', '\.', $extension) . '$/';
      // Get a listing of all template files in the path to search.
      $files = file_scan_directory($path, $regex, array('key' => 'filename'));
    
      // 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.
      foreach ($files as $template => $file) {
        // Ignore sub-theme templates for the current theme.
        if (strpos($file->uri, str_replace($subtheme_paths, '', $file->uri)) !== 0) {
          continue;
        }
        // Remove the extension from the filename.
        $template = str_replace($extension, '', $template);
        // Transform - in filenames to _ to match function naming scheme
        // for the purposes of searching.
        $hook = strtr($template, '-', '_');
        if (isset($cache[$hook])) {
          $implementations[$hook] = array(
            'template' => $template,
            'path' => dirname($file->uri),
          );
        }
    
        // Match templates based on the 'template' filename.
        foreach ($cache as $hook => $info) {
          if (isset($info['template'])) {
            $template_candidates = array($info['template'], str_replace($info['theme path'] . '/templates/', '', $info['template']));
            if (in_array($template, $template_candidates)) {
              $implementations[$hook] = array(
                'template' => $template,
                'path' => dirname($file->uri),
              );
            }
          }
        }
      }
    
      // Find templates that implement possible "suggestion" variants of registered
      // theme hooks and add those as new registered theme hooks. See
      // drupal_find_theme_functions() for more information about suggestions and
      // the use of 'pattern' and 'base hook'.
      $patterns = array_keys($files);
      foreach ($cache as $hook => $info) {
        $pattern = isset($info['pattern']) ? $info['pattern'] : ($hook . '__');
        if (!isset($info['base hook']) && !empty($pattern)) {
          // Transform _ in pattern to - to match file naming scheme
          // for the purposes of searching.
          $pattern = strtr($pattern, '_', '-');
    
          $matches = preg_grep('/^' . $pattern . '/', $patterns);
          if ($matches) {
            foreach ($matches as $match) {
              $file = $match;
              // Remove the extension from the filename.
              $file = str_replace($extension, '', $file);
              // Put the underscores back in for the hook name and register this
              // pattern.
              $arg_name = isset($info['variables']) ? 'variables' : 'render element';
              $implementations[strtr($file, '-', '_')] = array(
                'template' => $file,
                'path' => dirname($files[$match]->uri),
                $arg_name => $info[$arg_name],
                'base hook' => $hook,
              );
            }
          }
        }
      }
      return $implementations;
    }
    
    /**
     * Retrieves a setting for the current theme or for a given theme.
     *
     * The final setting is obtained from the last value found in the following
     * sources:
     * - 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
     * - 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.
     *
     * @param $setting_name
     *   The name of the setting to be retrieved.
     * @param $theme
     *   The name of a given theme; defaults to the current theme.
     *
     * @return
     *   The value of the requested setting, NULL if the setting does not exist.
     */
    function theme_get_setting($setting_name, $theme = NULL) {
      $cache = &drupal_static(__FUNCTION__, array());
    
      // If no key is given, use the current theme if we can determine it.
      if (!isset($theme)) {
        $theme = !empty($GLOBALS['theme_key']) ? $GLOBALS['theme_key'] : '';
      }
    
      if (empty($cache[$theme])) {
        // Create a theme settings object.
        $cache[$theme] = new ThemeSettings($theme);
    
        // Get the values for the theme-specific settings from the .info.yml files
        // of the theme and all its base themes.
        if ($theme) {
          $themes = list_themes();
          $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;
          }
          else {
            $theme_keys = array($theme);
          }
          foreach ($theme_keys as $theme_key) {
            if (!empty($themes[$theme_key]->info['settings'])) {
              $cache[$theme]->merge($themes[$theme_key]->info['settings']);
            }
          }
        }
    
        // Get the global settings from configuration.
        $cache[$theme]->merge(\Drupal::config('system.theme.global')->get());
    
        if ($theme) {
          // Get the saved theme-specific settings from the configuration system.
          $cache[$theme]->merge(\Drupal::config($theme . '.settings')->get());
    
          // If the theme does not support a particular feature, override the global
          // setting and set the value to NULL.
          //$supports = $cache[$theme]->get('supports');
          if (!empty($theme_object->info['features'])) {
            foreach (_system_default_theme_features() as $feature) {
              if (!in_array($feature, $theme_object->info['features'])) {
                $cache[$theme]->set('features.' . $feature, NULL);
              }
            }
          }
    
          // Generate the path to the logo image.
          if ($cache[$theme]->get('features.logo')) {
            $logo_path = $cache[$theme]->get('logo.path');
            if ($cache[$theme]->get('logo.use_default')) {
              $cache[$theme]->set('logo.url', file_create_url($theme_object->getPath() . '/logo.png'));
            }
            elseif ($logo_path) {
              $cache[$theme]->set('logo.url', file_create_url($logo_path));
            }
          }
    
          // Generate the path to the favicon.
          if ($cache[$theme]->get('features.favicon')) {
            $favicon_path = $cache[$theme]->get('favicon.path');
            if ($cache[$theme]->get('favicon.use_default')) {
              if (file_exists($favicon = $theme_object->getPath() . '/favicon.ico')) {
                $cache[$theme]->set('favicon.url', file_create_url($favicon));
              }
              else {
                $cache[$theme]->set('favicon.url', file_create_url('core/misc/favicon.ico'));
              }
            }
            elseif ($favicon_path) {
              $cache[$theme]->set('favicon.url', file_create_url($favicon_path));
            }
            else {
              $cache[$theme]->set('features.favicon', FALSE);
            }
          }
        }
      }
    
      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;
    }
    
    /**
     * Enables a given list of themes.
     *
     * @param $theme_list
     *   An array of theme names.
     *
     * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
     *   Use \Drupal::service('theme_handler')->enable().
     *
     * @see \Drupal\Core\Extension\ThemeHandler::enable().
     */
    function theme_enable($theme_list) {
      \Drupal::service('theme_handler')->enable($theme_list);
    }
    
    /**
     * Disables a given list of themes.
     *
     * @param $theme_list
     *   An array of theme names.
     *
     * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
     *   Use \Drupal::service('theme_handler')->disable().
     *
     * @see \Drupal\Core\Extension\ThemeHandler::disable().
     */
    function theme_disable($theme_list) {
      \Drupal::service('theme_handler')->disable($theme_list);
    }
    
    /**
     * @addtogroup themeable
     * @{
     */
    
    /**
     * Preprocess variables for theme_datetime().
     *
     * @param array $variables
     *   An associative array possibly containing:
     *   - attributes['timestamp']:
     *   - timestamp:
     *   - text:
     */
    function template_preprocess_datetime(&$variables) {
      // Format the 'datetime' attribute based on the timestamp.
      // @see http://www.w3.org/TR/html5-author/the-time-element.html#attr-time-datetime
      if (!isset($variables['attributes']['datetime']) && isset($variables['timestamp'])) {
        $variables['attributes']['datetime'] = format_date($variables['timestamp'], 'html_datetime', '', 'UTC');
      }
    
      // If no text was provided, try to auto-generate it.
      if (!isset($variables['text'])) {
        // Format and use a human-readable version of the timestamp, if any.
        if (isset($variables['timestamp'])) {
          $variables['text'] = format_date($variables['timestamp']);
          $variables['html'] = FALSE;
        }
        // Otherwise, use the literal datetime attribute.
        elseif (isset($variables['attributes']['datetime'])) {
          $variables['text'] = $variables['attributes']['datetime'];
          $variables['html'] = FALSE;
        }
      }
    
      // Add a 'datetime' class.
      $variables['attributes']['class'][] = 'datetime';
    
      $variables['attributes'] = new Attribute($variables['attributes']);
    }
    
    /**
     * Prepares variables for status message templates.
     *
     * Default template: status-messages.html.twig.
     *
     * @param array $variables
     *   An associative array containing:
     *   - display: (optional) May have a value of 'status' or 'error' when only
     *     displaying messages of that specific type.
     */
    function template_preprocess_status_messages(&$variables) {
      $variables['message_list'] = drupal_get_messages($variables['display']);
      $variables['status_headings'] = array(
        'status' => t('Status message'),
        'error' => t('Error message'),
        'warning' => t('Warning message'),
      );
    }
    
    /**
     * Prepares variables for links templates.
     *
     * Default template: links.html.twig.
     *
     * @param array $variables
     *   An associative array containing:
     *   - links: An associative array of links to be themed. The key for each link
     *     is used as its CSS class. Each link should be itself an array, with the
     *     following elements:
     *     - title: The link text.
     *     - route_name: (optional) The name of the route to link to. If omitted
     *       (and if 'href' is omitted as well), the 'title' is shown as
     *       a plain text item in the links list.
     *     - route_parameters: (optional) An array of route parameters for the link.
     *     - href: (optional) The link URL. It is preferred to use 'route_name' and
     *       'route parameters' for internal links. Use 'href' for links to external
     *       URLs. If omitted (and if 'route_name' is omitted as well), the 'title'
     *       is shown as a plain text item in the links list.
     *     - html: (optional) Whether or not 'title' is HTML. If set, the title
     *       will not be passed through
     *       \Drupal\Component\Utility\String::checkPlain().
     *     - attributes: (optional) Attributes for the anchor, or for the <span>
     *       tag used in its place if no 'href' is supplied. If element 'class' is
     *       included, it must be an array of one or more class names.
     *     If the 'href' element is supplied, the entire link array is passed to
     *     l() as its $options parameter.
     *   - attributes: A keyed array of attributes for the UL containing the
     *     list of links.
     *   - set_active_class: (optional) Whether each link should compare the
     *     route_name + route_parameters or href (path), language and query options
     *     to the current URL, to determine whether the link is "active". If so, an
     *     "active" class will be applied to the list item containing the link, as
     *     well as the link itself. It is important to use this sparingly since it
     *     is usually unnecessary and requires extra processing.
     *     For anonymous users, the "active" class will be calculated on the server,
     *     because most sites serve each anonymous user the same cached page anyway.
     *     For authenticated users, the "active" class will be calculated on the
     *     client (through JavaScript), only data- attributes are added to list
     *     items and contained links, to prevent breaking the render cache. The
     *     JavaScript is added in system_page_build().
     *   - heading: (optional) A heading to precede the links. May be an
     *     associative array or a string. If it's an array, it can have the
     *     following elements:
     *     - text: The heading text.
     *     - level: The heading level (e.g. 'h2', 'h3').
     *     - class: (optional) An array of the CSS classes for the heading.
     *     When using a string it will be used as the text of the heading and the
     *     level will default to 'h2'. Headings should be used on navigation menus
     *     and any list of links that consistently appears on multiple pages. To
     *     make the heading invisible use the 'visually-hidden' CSS class. Do not
     *     use 'display:none', which removes it from screen-readers and assistive
     *     technology. Headings allow screen-reader and keyboard only users to
     *     navigate to or skip the links. See
     *     http://juicystudio.com/article/screen-readers-display-none.php and
     *     http://www.w3.org/TR/WCAG-TECHS/H42.html for more information.
     *
     * Unfortunately links templates duplicate the "active" class handling of l()
     * and LinkGenerator::generate() because it needs to be able to set the "active"
     * class not on the links themselves ("a" tags), but on the list items ("li"
     * tags) that contain the links. This is necessary for CSS to be able to style
     * list items differently when the link is active, since CSS does not yet allow
     * one to style list items only if it contains a certain element with a certain
     * class. I.e. we cannot yet convert this jQuery selector to a CSS selector:
     *   jQuery('li:has("a.active")')
     *
     * @see l()
     * @see \Drupal\Core\Utility\LinkGenerator::generate()
     * @see system_page_build()
     */
    function template_preprocess_links(&$variables) {
      $links = $variables['links'];
      $heading = &$variables['heading'];
    
      if (!empty($links)) {
        // Prepend the heading to the list, if any.
        if (!empty($heading)) {
          // Convert a string heading into an array, using a H2 tag by default.
          if (is_string($heading)) {
            $heading = array('text' => $heading);
          }
          // Merge in default array properties into $heading.
          $heading += array(
            'level' => 'h2',
            'attributes' => array(),
          );
          // @todo Remove backwards compatibility for $heading['class'].
          if (isset($heading['class'])) {
            $heading['attributes']['class'] = $heading['class'];
          }
          // Convert the attributes array into an Attribute object.
          $heading['attributes'] = new Attribute($heading['attributes']);
          $heading['text'] = String::checkPlain($heading['text']);
        }
    
        $variables['links'] = array();
        foreach ($links as $key => $link) {
          $item = array();
          $link += array(
            'href' => NULL,
            'route_name' => NULL,
            'route_parameters' => NULL,
            'ajax' => NULL,
          );
    
          $li_attributes = array('class' => array());
          // Use the array key as class name.
          $li_attributes['class'][] = drupal_html_class($key);
    
          $keys = array('title', 'href', 'route_name', 'route_parameters');
          $link_element = array(
            '#type' => 'link',
            '#title' => $link['title'],
            '#options' => array_diff_key($link, array_combine($keys, $keys)),
            '#href' => $link['href'],
            '#route_name' => $link['route_name'],
            '#route_parameters' => $link['route_parameters'],
            '#ajax' => $link['ajax'],
          );
    
          // Handle links and ensure that the active class is added on the LIs, but
          // only if the 'set_active_class' option is not empty.
          if (isset($link['href']) || isset($link['route_name'])) {
            if (!empty($variables['set_active_class'])) {
    
              // Also enable set_active_class for the contained link.
              $link_element['#options']['set_active_class'] = TRUE;
    
              if (!empty($link['language'])) {
                $li_attributes['hreflang'] = $link['language']->id;
              }
    
              // Add a "data-drupal-link-query" attribute to let the
              // drupal.active-link library know the query in a standardized manner.
              if (!empty($link['query'])) {
                $query = $link['query'];
                ksort($query);
                $li_attributes['data-drupal-link-query'] = Json::encode($query);
              }
    
              if (isset($link['route_name'])) {
                $path = \Drupal::service('url_generator')->getPathFromRoute($link['route_name'], $link['route_parameters']);
              }
              else {
                $path = $link['href'];
              }
    
              // Add a "data-drupal-link-system-path" attribute to let the
              // drupal.active-link library know the path in a standardized manner.
              $li_attributes['data-drupal-link-system-path'] = \Drupal::service('path.alias_manager.cached')->getSystemPath($path);
            }
    
            $item['link'] = $link_element;
          }
    
          // Handle title-only text items.
          $text = (!empty($link['html']) ? $link['title'] : String::checkPlain($link['title']));
          $item['text'] = $text;
          if (isset($link['attributes'])) {
            $item['text_attributes'] = new Attribute($link['attributes']);
          }
    
          // Handle list item attributes.
          $item['attributes'] = new Attribute($li_attributes);
    
          // Add the item to the list of links.
          $variables['links'][] = $item;
        }
      }
    }
    
    /**
     * Returns HTML for an image.
     *
     * @param $variables
     *   An associative array containing:
     *   - uri: Either the path of the image file (relative to base_path()) or a
     *     full URL.
     *   - width: The width of the image (if known).
     *   - height: The height of the image (if known).
     *   - alt: The alternative text for text-based browsers. HTML 4 and XHTML 1.0
     *     always require an alt attribute. The HTML 5 draft allows the alt
     *     attribute to be omitted in some cases. Therefore, this variable defaults
     *     to an empty string, but can be set to NULL for the attribute to be
     *     omitted. Usually, neither omission nor an empty string satisfies
     *     accessibility requirements, so it is strongly encouraged for code
     *     calling _theme('image') to pass a meaningful value for this variable.
     *     - http://www.w3.org/TR/REC-html40/struct/objects.html#h-13.8
     *     - http://www.w3.org/TR/xhtml1/dtds.html
     *     - http://dev.w3.org/html5/spec/Overview.html#alt
     *   - title: The title text is displayed when the image is hovered in some
     *     popular browsers.
     *   - attributes: Associative array of attributes to be placed in the img tag.
     */
    function theme_image($variables) {
      $attributes = $variables['attributes'];
      $attributes['src'] = file_create_url($variables['uri']);
    
      foreach (array('width', 'height', 'alt', 'title') as $key) {
        if (isset($variables[$key])) {
          $attributes[$key] = $variables[$key];
        }
      }
    
      return '<img' . new Attribute($attributes) . ' />';
    }
    
    /**
     * #pre_render callback to transform children of an element into #rows suitable for theme_table().
     *
     * This function converts sub-elements of an element of #type 'table' to be
     * suitable for theme_table():
     * - The first level of sub-elements are table rows. Only the #attributes
     *   property is taken into account.
     * - The second level of sub-elements is converted into columns for the
     *   corresponding first-level table row.
     *
     * Simple example usage:
     * @code
     * $form['table'] = array(
     *   '#type' => 'table',
     *   '#header' => array(t('Title'), array('data' => t('Operations'), 'colspan' => '1')),
     *   // Optionally, to add tableDrag support:
     *   '#tabledrag' => array(
     *     array(
     *       'action' => 'order',
     *       'relationship' => 'sibling',
     *       'group' => 'thing-weight',
     *     ),
     *   ),
     * );
     * foreach ($things as $row => $thing) {
     *   $form['table'][$row]['#weight'] = $thing['weight'];
     *
     *   $form['table'][$row]['title'] = array(
     *     '#type' => 'textfield',
     *     '#default_value' => $thing['title'],
     *   );
     *
     *   // Optionally, to add tableDrag support:
     *   $form['table'][$row]['#attributes']['class'][] = 'draggable';
     *   $form['table'][$row]['weight'] = array(
     *     '#type' => 'textfield',
     *     '#title' => t('Weight for @title', array('@title' => $thing['title'])),
     *     '#title_display' => 'invisible',
     *     '#size' => 4,
     *     '#default_value' => $thing['weight'],
     *     '#attributes' => array('class' => array('thing-weight')),
     *   );
     *
     *   // The amount of link columns should be identical to the 'colspan'
     *   // attribute in #header above.
     *   $form['table'][$row]['edit'] = array(
     *     '#type' => 'link',
     *     '#title' => t('Edit'),
     *     '#href' => 'thing/' . $row . '/edit',
     *   );
     * }
     * @endcode
     *
     * @param array $element
     *   A structured array containing two sub-levels of elements. Properties used:
     *   - #tabledrag: The value is a list of $options arrays that are passed to
     *     drupal_attach_tabledrag(). The HTML ID of the table is added to each
     *     $options array.
     *
     * @see system_element_info()
     * @see theme_table()
     * @see drupal_process_attached()
     * @see drupal_attach_tabledrag()
     */
    function drupal_pre_render_table(array $element) {
      foreach (element_children($element) as $first) {
        $row = array('data' => array());
        // Apply attributes of first-level elements as table row attributes.
        if (isset($element[$first]['#attributes'])) {
          $row += $element[$first]['#attributes'];
        }
        // Turn second-level elements into table row columns.
        // @todo Do not render a cell for children of #type 'value'.
        // @see http://drupal.org/node/1248940
        foreach (element_children($element[$first]) as $second) {
          // Assign the element by reference, so any potential changes to the
          // original element are taken over.
          $column = array('data' => &$element[$first][$second]);
    
          // Apply wrapper attributes of second-level elements as table cell
          // attributes.
          if (isset($element[$first][$second]['#wrapper_attributes'])) {
            $column += $element[$first][$second]['#wrapper_attributes'];
          }
    
          $row['data'][] = $column;
        }
        $element['#rows'][] = $row;
      }
    
      // Take over $element['#id'] as HTML ID attribute, if not already set.
      element_set_attributes($element, array('id'));
    
    
      // Add sticky headers, if applicable.
      if (count($element['#header']) && $element['#sticky']) {
        $element['#attached']['library'][] = 'core/drupal.tableheader';
        // Add 'sticky-enabled' class to the table to identify it for JS.
        // This is needed to target tables constructed by this function.
        $element['#attributes']['class'][] = 'sticky-enabled';
      }
      // If the table has headers and it should react responsively to columns hidden
      // with the classes represented by the constants RESPONSIVE_PRIORITY_MEDIUM
      // and RESPONSIVE_PRIORITY_LOW, add the tableresponsive behaviors.
      if (count($element['#header']) && $element['#responsive']) {
        $element['#attached']['library'][] = 'core/drupal.tableresponsive';
        // Add 'responsive-enabled' class to the table to identify it for JS.
        // This is needed to target tables constructed by this function.
        $element['#attributes']['class'][] = 'responsive-enabled';
      }
    
      // If the custom #tabledrag is set and there is a HTML ID, add the table's
      // HTML ID to the options and attach the behavior.
      if (!empty($element['#tabledrag']) && isset($element['#attributes']['id'])) {
        foreach ($element['#tabledrag'] as $options) {
          $options['table_id'] = $element['#attributes']['id'];
          drupal_attach_tabledrag($element, $options);
        }
      }
    
      return $element;
    }
    
    /**
     * Returns HTML for a table.
     *
     * @param $variables
     *   An associative array containing:
     *   - header: An array containing the table headers. Each element of the array
     *     can be either a localized string or an associative array with the
     *     following keys:
     *     - "data": The localized title of the table column.
     *     - "field": The database field represented in the table column (required
     *       if user is to be able to sort on this column).
     *     - "sort": A default sort order for this column ("asc" or "desc"). Only
     *        one column should be given a default sort order because table sorting
     *        only applies to one column at a time.
     *     - "class": An array of values for the 'class' attribute. In particular,
     *        the least important columns that can be hidden on narrow and medium
     *        width screens should have a 'priority-low' class, referenced with the
     *        RESPONSIVE_PRIORITY_LOW constant. Columns that should be shown on
     *        medium+ wide screens should be marked up with a class of
     *        'priority-medium', referenced by with the RESPONSIVE_PRIORITY_MEDIUM
     *        constant. Themes may hide columns with one of these two classes on
     *        narrow viewports to save horizontal space.
     *     - Any HTML attributes, such as "colspan", to apply to the column header
     *       cell.
     *   - rows: An array of table rows. Every row is an array of cells, or an
     *     associative array with the following keys:
     *     - "data": an array of cells
     *     - Any HTML attributes, such as "class", to apply to the table row.
     *     - "no_striping": a boolean indicating that the row should receive no
     *       'even / odd' styling. Defaults to FALSE.
     *     Each cell can be either a string or an associative array with the
     *     following keys:
     *     - "data": The string to display in the table cell.
     *     - "header": Indicates this cell is a header.
     *     - Any HTML attributes, such as "colspan", to apply to the table cell.
     *     Here's an example for $rows:
     *     @code
     *     $rows = array(
     *       // Simple row
     *       array(
     *         'Cell 1', 'Cell 2', 'Cell 3'
     *       ),
     *       // Row with attributes on the row and some of its cells.
     *       array(
     *         'data' => array('Cell 1', array('data' => 'Cell 2', 'colspan' => 2)), 'class' => array('funky')
     *       )
     *     );
     *     @endcode
     *   - attributes: An array of HTML attributes to apply to the table tag.
     *   - caption: A localized string to use for the <caption> tag.
     *   - colgroups: An array of column groups. Each element of the array can be
     *     either:
     *     - An array of columns, each of which is an associative array of HTML
     *       attributes applied to the COL element.
     *     - An array of attributes applied to the COLGROUP element, which must
     *       include a "data" attribute. To add attributes to COL elements, set the
     *       "data" attribute with an array of columns, each of which is an
     *       associative array of HTML attributes.
     *     Here's an example for $colgroup:
     *     @code
     *     $colgroup = array(
     *       // COLGROUP with one COL element.
     *       array(
     *         array(
     *           'class' => array('funky'), // Attribute for the COL element.
     *         ),
     *       ),
     *       // Colgroup with attributes and inner COL elements.
     *       array(
     *         'data' => array(
     *           array(
     *             'class' => array('funky'), // Attribute for the COL element.
     *           ),
     *         ),
     *         'class' => array('jazzy'), // Attribute for the COLGROUP element.
     *       ),
     *     );
     *     @endcode
     *     These optional tags are used to group and set properties on columns
     *     within a table. For example, one may easily group three columns and
     *     apply same background style to all.
     *   - sticky: Use a "sticky" table header.
     *   - empty: The message to display in an extra row if table does not have any
     *     rows.
     */
    function theme_table($variables) {
      $header = $variables['header'];
      $rows = $variables['rows'];
      $attributes = $variables['attributes'];
      $caption = $variables['caption'];
      $colgroups = $variables['colgroups'];
      $sticky = $variables['sticky'];
      $responsive = $variables['responsive'];
      $empty = $variables['empty'];
    
      $output = '<table' . new Attribute($attributes) . ">\n";
    
      if (isset($caption)) {
        $output .= '<caption>' . $caption . "</caption>\n";
      }
    
      // Format the table columns:
      if (count($colgroups)) {
        foreach ($colgroups as $colgroup) {
          $attributes = array();
    
          // Check if we're dealing with a simple or complex column
          if (isset($colgroup['data'])) {
            foreach ($colgroup as $key => $value) {
              if ($key == 'data') {
                $cols = $value;
              }
              else {
                $attributes[$key] = $value;
              }
            }
          }
          else {
            $cols = $colgroup;
          }
    
          // Build colgroup
          if (is_array($cols) && count($cols)) {
            $output .= ' <colgroup' . new Attribute($attributes) . '>';
            foreach ($cols as $col) {
              $output .= ' <col' . new Attribute($col) . ' />';
            }
            $output .= " </colgroup>\n";
          }
          else {
            $output .= ' <colgroup' . new Attribute($attributes) . " />\n";
          }
        }
      }
    
      // Add the 'empty' row message if available.
      if (!count($rows) && $empty) {
        $header_count = 0;
        foreach ($header as $header_cell) {
          if (is_array($header_cell)) {
            $header_count += isset($header_cell['colspan']) ? $header_cell['colspan'] : 1;
          }
          else {
            $header_count++;
          }
        }
        $rows[] = array(array('data' => $empty, 'colspan' => $header_count, 'class' => array('empty', 'message')));
      }
    
      $responsive = array();
      // Format the table header:
      if (count($header)) {
        $ts = tablesort_init($header);
        // HTML requires that the thead tag has tr tags in it followed by tbody
        // tags. Using ternary operator to check and see if we have any rows.
        $output .= (count($rows) ? ' <thead><tr>' : ' <tr>');
        $i = 0;
        foreach ($header as $cell) {
          $i++;
          // Track responsive classes for each column as needed. Only the header
          // cells for a column are marked up with the responsive classes by a
          // module developer or themer. The responsive classes on the header cells
          // must be transferred to the content cells.
          if (!empty($cell['class']) && is_array($cell['class'])) {
            if (in_array(RESPONSIVE_PRIORITY_MEDIUM, $cell['class'])) {
              $responsive[$i] =  RESPONSIVE_PRIORITY_MEDIUM;
            }
            elseif (in_array(RESPONSIVE_PRIORITY_LOW, $cell['class'])) {
              $responsive[$i] =  RESPONSIVE_PRIORITY_LOW;
            }
          }
          $cell = tablesort_header($cell, $header, $ts);
          $output .= _theme_table_cell($cell, TRUE);
        }
        // Using ternary operator to close the tags based on whether or not there are rows
        $output .= (count($rows) ? " </tr></thead>\n" : "</tr>\n");
      }
      else {
        $ts = array();
      }
    
      // Format the table rows:
      if (count($rows)) {
        $output .= "<tbody>\n";
        $flip = array('even' => 'odd', 'odd' => 'even');
        $class = 'even';
        foreach ($rows as $row) {
          // Check if we're dealing with a simple or complex row
          if (isset($row['data'])) {
            $cells = $row['data'];
            $no_striping = isset($row['no_striping']) ? $row['no_striping'] : FALSE;
    
            // Set the attributes array and exclude 'data' and 'no_striping'.
            $attributes = $row;
            unset($attributes['data']);
            unset($attributes['no_striping']);
          }
          else {
            $cells = $row;
            $attributes = array();
            $no_striping = FALSE;
          }
          if (count($cells)) {
            // Add odd/even class
            if (!$no_striping) {
              $class = $flip[$class];
              $attributes['class'][] = $class;
            }
    
            // Build row
            $output .= ' <tr' . new Attribute($attributes) . '>';
            $i = 0;
            foreach ($cells as $cell) {
              $i++;
              // Add active class if needed for sortable tables.
              $cell = tablesort_cell($cell, $header, $ts, $i);
              // Copy RESPONSIVE_PRIORITY_LOW/RESPONSIVE_PRIORITY_MEDIUM
              // class from header to cell as needed.
              if (isset($responsive[$i])) {
                if (is_array($cell)) {
                  $cell['class'][] = $responsive[$i];
                }
                else {
                  $cell = array('data' => $cell, 'class' => $responsive[$i]);
                }
              }
              $output .= _theme_table_cell($cell);
            }
            $output .= " </tr>\n";
          }
        }
        $output .= "</tbody>\n";
      }
    
      $output .= "</table>\n";
      return $output;
    }
    
    /**
     * Returns HTML for a marker for new or updated content.
     *
     * @param $variables
     *   An associative array containing:
     *   - type: Number representing the marker type to display. See MARK_NEW,
     *     MARK_UPDATED, MARK_READ.
     */
    function theme_mark($variables) {
      $type = $variables['status'];
      if (\Drupal::currentUser()->isAuthenticated()) {
        if ($type == MARK_NEW) {
          return ' <span class="marker">' . t('new') . '</span>';
        }
        elseif ($type == MARK_UPDATED) {
          return ' <span class="marker">' . t('updated') . '</span>';
        }
      }
    }
    
    /**
     * Prepares variables for item list templates.
     *
     * Default template: item-list.html.twig.
     *
     * @param array $variables
     *   An associative array containing:
     *   - items: An array of items to be displayed in the list. Each item can be
     *     either a string or a render array. If #type, #theme, or #markup
     *     properties are not specified for child render arrays, they will be
     *     inherited from the parent list, allowing callers to specify larger
     *     nested lists without having to explicitly specify and repeat the
     *     render properties for all nested child lists.
     *   - title: A title to be prepended to the list.
     *   - list_type: The type of list to return (e.g. "ul", "ol").
     *
     * @see http://drupal.org/node/1842756
     */
    function template_preprocess_item_list(&$variables) {
      $variables['title'] = (string) $variables['title'];
    
      foreach ($variables['items'] as &$item) {
        $attributes = array();
        // If the item value is an array, then it is a render array.
        if (is_array($item)) {
          // List items support attributes via the '#wrapper_attributes' property.
          if (isset($item['#wrapper_attributes'])) {
            $attributes = $item['#wrapper_attributes'];
          }
          // Determine whether there are any child elements in the item that are not
          // fully-specified render arrays. If there are any, then the child
          // elements present nested lists and we automatically inherit the render
          // array properties of the current list to them.
          foreach (Element::children($item) as $key) {
            $child = &$item[$key];
            // If this child element does not specify how it can be rendered, then
            // we need to inherit the render properties of the current list.
            if (!isset($child['#type']) && !isset($child['#theme']) && !isset($child['#markup'])) {
              // Since theme_item_list() supports both strings and render arrays as
              // items, the items of the nested list may have been specified as the
              // child elements of the nested list, instead of #items. For
              // convenience, we automatically move them into #items.
              if (!isset($child['#items'])) {
                // This is the same condition as in element_children(), which cannot
                // be used here, since it triggers an error on string values.
                foreach ($child as $child_key => $child_value) {
                  if ($child_key[0] !== '#') {
                    $child['#items'][$child_key] = $child_value;
                    unset($child[$child_key]);
                  }
                }
              }
              // Lastly, inherit the original theme variables of the current list.
              $child['#theme'] = $variables['theme_hook_original'];
              $child['#list_type'] = $variables['list_type'];
            }
          }
        }
    
        // Set the item's value and attributes for the template.
        $item = array(
          'value' => $item,
          'attributes' => new Attribute($attributes),
        );
      }
    }
    
    /**
     * Prepares variables for feed icon templates.
     *
     * Default template: feed-icon.html.twig.
     *
     * @param array $variables
     *   An associative array containing:
     *   - url: An internal system path or a fully qualified external URL of the
     *     feed.
     *   - title: A descriptive title of the feed.
     */
    function template_preprocess_feed_icon(&$variables) {
      $text = t('Subscribe to !feed-title', array('!feed-title' => $variables['title']));
      $variables['icon'] = array(
        '#theme' => 'image__feed_icon',
        '#uri' => 'core/misc/feed.png',
        '#width' => 16,
        '#height' => 16,
        '#alt' => $text,
      );
      $variables['attributes']['class'] = array('feed-icon');
      // Stripping tags because that's what l() used to do.
      $variables['attributes']['title'] = strip_tags($text);
    }
    
    /**
     * Returns HTML for a "more" link, like those used in blocks.
     *
     * @param $variables
     *   An associative array containing:
     *   - url: The URL of the main page.
     *   - title: A descriptive verb for the link, like 'Read more'.
     */
    function theme_more_link($variables) {
      return '<div class="more-link">' . l(t('More'), $variables['url'], array('attributes' => array('title' => $variables['title']))) . '</div>';
    }
    
    /**
     * Returns HTML for an indentation div; used for drag and drop tables.
     *
     * @param $variables
     *   An associative array containing:
     *   - size: Optional. The number of indentations to create.
     */
    function theme_indentation($variables) {
      $output = '';
      for ($n = 0; $n < $variables['size']; $n++) {
        $output .= '<div class="indentation">&nbsp;</div>';
      }
      return $output;
    }
    
    /**
     * Prepares variables for container templates.
     *
     * Default template: container.html.twig.
     *
     * @param array $variables
     *   An associative array containing:
     *   - element: An associative array containing the properties of the element.
     *     Properties used: #id, #attributes, #children.
     */
    function template_preprocess_container(&$variables) {
      $element = $variables['element'];
      // Ensure #attributes is set.
      $element += array('#attributes' => array());
    
      // Special handling for form elements.
      if (isset($element['#array_parents'])) {
        // Assign an html ID.
        if (!isset($element['#attributes']['id'])) {
          $element['#attributes']['id'] = $element['#id'];
        }
        // Add the 'form-wrapper' class.
        $element['#attributes']['class'][] = 'form-wrapper';
      }
    
      $variables['children'] = $element['#children'];
      $variables['attributes'] = $element['#attributes'];
    }
    
    /**
     * @} End of "addtogroup themeable".
     */
    
    /**
     * Returns HTML output for a single table cell for theme_table().
     *
     * @param $cell
     *   Array of cell information, or string to display in cell.
     * @param bool $header
     *   TRUE if this cell is a table header cell, FALSE if it is an ordinary
     *   table cell. If $cell is an array with element 'header' set to TRUE, that
     *   will override the $header parameter.
     *
     * @return
     *   HTML for the cell.
     */
    function _theme_table_cell($cell, $header = FALSE) {
      $attributes = '';
    
      if (is_array($cell)) {
        $data = isset($cell['data']) ? $cell['data'] : '';
        // Cell's data property can be a string or a renderable array.
        if (is_array($data)) {
          $data = drupal_render($data);
        }
        $header |= isset($cell['header']);
        unset($cell['data']);
        unset($cell['header']);
        $attributes = new Attribute($cell);
      }
      else {
        $data = $cell;
      }
    
      if ($header) {
        $output = "<th$attributes>$data</th>";
      }
      else {
        $output = "<td$attributes>$data</td>";
      }
    
      return $output;
    }
    
    /**
     * Adds a default set of helper variables for preprocessors and templates.
     *
     * This function is called for theme hooks implemented as templates only, not
     * for theme hooks implemented as functions. This preprocess function is the
     * first in the sequence of preprocessing functions that are called when
     * preparing variables for a template. See _theme() for more details about the
     * full sequence.
     *
     * @see _theme()
     */
    function template_preprocess(&$variables, $hook, $info) {
      // Tell all templates where they are located.
      $variables['directory'] = path_to_theme();
    
      // Merge in variables that don't depend on hook and don't change during a
      // single page request.
      // Use the advanced drupal_static() pattern, since this is called very often.
      static $drupal_static_fast;
      if (!isset($drupal_static_fast)) {
        $drupal_static_fast['default_variables'] = &drupal_static(__FUNCTION__);
      }
      $default_variables = &$drupal_static_fast['default_variables'];
      if (!isset($default_variables)) {
        $default_variables = _template_preprocess_default_variables();
      }
      $variables += $default_variables;
    
      // When theming a render element, merge its #attributes into
      // $variables['attributes'].
      if (isset($info['render element'])) {
        $key = $info['render element'];
        if (isset($variables[$key]['#attributes'])) {
          $variables['attributes'] = NestedArray::mergeDeep($variables['attributes'], $variables[$key]['#attributes']);
        }
      }
    }
    
    /**
     * Returns hook-independent variables to template_preprocess().
     */
    function _template_preprocess_default_variables() {
      // Variables that don't depend on a database connection.
      $variables = array(
        'attributes' => array(),
        'title_attributes' => array(),
        'content_attributes' => array(),
        'title_prefix' => array(),
        'title_suffix' => array(),
        'db_is_active' => !defined('MAINTENANCE_MODE'),
        'is_admin' => FALSE,
        'logged_in' => FALSE,
      );
    
      // drupal_is_front_page() might throw an exception.
      try {
        $variables['is_front'] = drupal_is_front_page();
      }
      catch (Exception $e) {
        // If the database is not yet available, set default values for these
        // variables.
        $variables['is_front'] = FALSE;
        $variables['db_is_active'] = FALSE;
      }
    
      // Give modules a chance to alter the default template variables.
      \Drupal::moduleHandler()->alter('template_preprocess_default_variables', $variables);
    
      return $variables;
    }
    
    /**
     * #pre_render callback for the html element type.
     *
     * @param array $element
     *   A structured array containing the html element type build properties.
     *
     * @see system_element_info()
     */
    function drupal_pre_render_html(array $element) {
      // Add favicon.
      if (theme_get_setting('features.favicon')) {
        $favicon = theme_get_setting('favicon.url');
        $type = theme_get_setting('favicon.mimetype');
        $element['#attached']['drupal_add_html_head_link'][][] = array(
          'rel' => 'shortcut icon',
          'href' => UrlHelper::stripDangerousProtocols($favicon),
          'type' => $type,
        );
      }
    
      return $element;
    }
    /**
     * Prepares variables for HTML document templates.
     *
     * Default template: html.html.twig.
     *
     * @param array $variables
     *   An associative array containing:
     *   - page: A render element representing the page.
     *
     * @see system_elements()
     */
    function template_preprocess_html(&$variables) {
      /** @var $page \Drupal\Core\Page\HtmlPage */
      $page = $variables['page_object'];
    
      $variables['html_attributes'] = $page->getHtmlAttributes();
      $variables['attributes'] = $page->getBodyAttributes();
      $variables['page'] = $page->getContent();
    
      // Compile a list of classes that are going to be applied to the body element.
      // This allows advanced theming based on context (home page, node of certain type, etc.).
      $body_classes = $variables['attributes']['class'];
      $body_classes[] = 'html';
      // Add a class that tells us whether we're on the front page or not.
      $body_classes[] = $variables['is_front'] ? 'front' : 'not-front';
      // Add a class that tells us whether the page is viewed by an authenticated user or not.
      $body_classes[] = $variables['logged_in'] ? 'logged-in' : 'not-logged-in';
      $variables['attributes']['class'] = $body_classes;
    
      // Populate the body classes.
      if ($suggestions = theme_get_suggestions(arg(), 'page', '-')) {
        foreach ($suggestions as $suggestion) {
          if ($suggestion != 'page-front') {
            // Add current suggestion to page classes to make it possible to theme
            // the page depending on the current page type (e.g. node, admin, user,
            // etc.) as well as more specific data like node-12 or node-edit.
            $variables['attributes']['class'][] = drupal_html_class($suggestion);
          }
        }
      }
    
      $site_config = \Drupal::config('system.site');
      // Construct page title.
      if ($page->hasTitle()) {
        $head_title = array(
          'title' => strip_tags($page->getTitle()),
          'name' => String::checkPlain($site_config->get('name')),
        );
      }
      // @todo Remove once views is not bypassing the view subscriber anymore.
      //   @see http://drupal.org/node/2068471
      elseif (drupal_is_front_page()) {
        $head_title = array(
          'title' => t('Home'),
          'name' => String::checkPlain($site_config->get('name')),
        );
      }
      else {
        $head_title = array('name' => String::checkPlain($site_config->get('name')));
        if ($site_config->get('slogan')) {
          $head_title['slogan'] = strip_tags(filter_xss_admin($site_config->get('slogan')));
        }
      }
    
      $variables['head_title_array'] = $head_title;
      $variables['head_title'] = implode(' | ', $head_title);
    
      // Display the html.html.twig's default mobile metatags for responsive design.
      $elements = array(
        'MobileOptimized' => array(
          '#tag' => 'meta',
          '#attributes' => array(
            'name' => 'MobileOptimized',
            'content' => 'width',
          ),
        ),
        'HandheldFriendly' => array(
          '#tag' => 'meta',
          '#attributes' => array(
            'name' => 'HandheldFriendly',
            'content' => 'true',
          ),
        ),
        'viewport' => array(
          '#tag' => 'meta',
          '#attributes' => array(
            'name' => 'viewport',
            'content' => 'width=device-width',
          ),
        ),
      );
      foreach ($elements as $name => $element) {
        drupal_add_html_head($element, $name);
      }
    
      $variables['page_top'][] = array('#markup' => $page->getBodyTop());
      $variables['page_bottom'][] = array('#markup' => $page->getBodyBottom());
    
      // Add footer scripts as '#markup' so they can be rendered with other
      // elements in page_bottom.
      $footer_scripts = new RenderWrapper('drupal_get_js', array('footer'));
      $variables['page_bottom'][] = array('#markup' => $footer_scripts);
    
      // Wrap function calls in an object so they can be called when printed.
      $variables['head'] = new RenderWrapper('drupal_get_html_head');
      $variables['styles'] = new RenderWrapper('drupal_get_css');
      $variables['scripts'] = new RenderWrapper('drupal_get_js');
    }
    
    /**
     * Prepares variables for the page template.
     *
     * Default template: page.html.twig.
     *
     * Most themes utilize their own copy of page.html.twig. The default is located
     * inside "modules/system/page.html.twig". Look in there for the full list of
     * variables.
     *
     * Uses the arg() function to generate a series of page template suggestions
     * based on the current path.
     *
     * @see drupal_render_page()
     */
    function template_preprocess_page(&$variables) {
      $language_interface = \Drupal::languageManager()->getCurrentLanguage();
      $site_config = \Drupal::config('system.site');
    
      // Move some variables to the top level for themer convenience and template cleanliness.
      $variables['show_messages'] = $variables['page']['#show_messages'];
      $variables['title'] = $variables['page']['#title'];
    
      foreach (system_region_list($GLOBALS['theme']) as $region_key => $region_name) {
        if (!isset($variables['page'][$region_key])) {
          $variables['page'][$region_key] = array();
        }
      }
    
      // Set up layout variable.
      $variables['layout'] = 'none';
      if (!empty($variables['page']['sidebar_first'])) {
        $variables['layout'] = 'first';
      }
      if (!empty($variables['page']['sidebar_second'])) {
        $variables['layout'] = ($variables['layout'] == 'first') ? 'both' : 'second';
      }
    
      $variables['base_path']         = base_path();
      $variables['front_page']        = url();
      $variables['feed_icons']        = drupal_get_feeds();
      $variables['language']          = $language_interface;
      $variables['language']->dir     = $language_interface->direction ? 'rtl' : 'ltr';
      $variables['logo']              = theme_get_setting('logo.url');
      $variables['main_menu']         = theme_get_setting('features.main_menu') ? menu_main_menu() : array();
      $variables['secondary_menu']    = theme_get_setting('features.secondary_menu') ? menu_secondary_menu() : array();
      $variables['action_links']      = menu_get_local_actions();
      $variables['site_name']         = (theme_get_setting('features.name') ? String::checkPlain($site_config->get('name')) : '');
      $variables['site_slogan']       = (theme_get_setting('features.slogan') ? filter_xss_admin($site_config->get('slogan')) : '');
      $variables['tabs']              = menu_local_tabs();
    
      // Pass the main menu and secondary menu to the template as render arrays.
      if (!empty($variables['main_menu'])) {
        $variables['main_menu'] = array(
          '#theme' =>'links__system_main_menu',
          '#links' => $variables['main_menu'],
          '#heading' => array(
            'text' => t('Main menu'),
            'class' => array('visually-hidden'),
          ),
          '#set_active_class' => TRUE,
        );
      }
      if (!empty($variables['secondary_menu'])) {
        $variables['secondary_menu'] = array(
          '#theme' =>'links__system_secondary_menu',
          '#links' => $variables['secondary_menu'],
          '#heading' => array(
            'text' => t('Secondary menu'),
            'class' => array('visually-hidden'),
          ),
          '#set_active_class' => TRUE,
        );
      }
    
      if ($node = \Drupal::request()->attributes->get('node')) {
        $variables['node'] = $node;
      }
    
      // Prepare render array for messages. drupal_get_messages() is called later,
      // when this variable is rendered in a theme function or template file.
      $variables['messages'] = array(
        '#theme' => 'status_messages',
        '#access' => $variables['show_messages'],
      );
    
      // Set the breadcrumb last, so as to increase the chance of being able to
      // re-use the cache of an already retrieved menu containing the active link
      // for the current page.
      // @see menu_tree_page_data()
      $variables['breadcrumb'] = array(
        '#theme' => 'breadcrumb',
        '#breadcrumb' => \Drupal::service('breadcrumb')->build(\Drupal::request()->attributes->all()),
      );
    }
    
    /**
     * Generate an array of suggestions from path arguments.
     *
     * This is typically called for adding to the suggestions in
     * hook_theme_suggestions_HOOK_alter() or adding to 'attributes' class key
     * variables from within preprocess functions, when wanting to base the
     * additional suggestions or classes on the path of the current page.
     *
     * @param $args
     *   An array of path arguments, such as from function arg().
     * @param $base
     *   A string identifying the base 'thing' from which more specific suggestions
     *   are derived. For example, 'page' or 'html'.
     * @param $delimiter
     *   The string used to delimit increasingly specific information. The default
     *   of '__' is appropriate for theme hook suggestions. '-' is appropriate for
     *   extra classes.
     *
     * @return
     *   An array of suggestions, suitable for adding to
     *   hook_theme_suggestions_HOOK_alter() or to $variables['attributes']['class']
     *   if the suggestions represent extra CSS classes.
     */
    function theme_get_suggestions($args, $base, $delimiter = '__') {
    
      // Build a list of suggested theme hooks or body classes in order of
      // specificity. One suggestion is made for every element of the current path,
      // though numeric elements are not carried to subsequent suggestions. For
      // example, for $base='page', http://www.example.com/node/1/edit would result
      // in the following suggestions and body classes:
      //
      // page__node              page-node
      // page__node__%           page-node-%
      // page__node__1           page-node-1
      // page__node__edit        page-node-edit
    
      $suggestions = array();
      $prefix = $base;
      foreach ($args as $arg) {
        // Remove slashes or null per SA-CORE-2009-003 and change - (hyphen) to _
        // (underscore).
        //
        // When we discover templates in @see drupal_find_theme_templates,
        // hyphens (-) are converted to underscores (_) before the theme hook
        // is registered. We do this because the hyphens used for delimiters
        // in hook suggestions cannot be used in the function names of the
        // associated preprocess functions. Any page templates designed to be used
        // on paths that contain a hyphen are also registered with these hyphens
        // converted to underscores so here we must convert any hyphens in path
        // arguments to underscores here before fetching theme hook suggestions
        // to ensure the templates are appropriately recognized.
        $arg = str_replace(array("/", "\\", "\0", '-'), array('', '', '', '_'), $arg);
        // The percent acts as a wildcard for numeric arguments since
        // asterisks are not valid filename characters on many filesystems.
        if (is_numeric($arg)) {
          $suggestions[] = $prefix . $delimiter . '%';
        }
        $suggestions[] = $prefix . $delimiter . $arg;
        if (!is_numeric($arg)) {
          $prefix .= $delimiter . $arg;
        }
      }
      if (drupal_is_front_page()) {
        // Front templates should be based on root only, not prefixed arguments.
        $suggestions[] = $base . $delimiter . 'front';
      }
    
      return $suggestions;
    }
    
    /**
     * Prepare variables for maintenance page templates.
     *
     * Default template: maintenance-page.html.twig.
     *
     * The variables array generated here is a mirror of
     * template_preprocess_page(). This preprocessor will run its course when
     * theme_maintenance_page() is invoked. An alternate template file of
     * maintenance-page--offline.html.twig can be used when the database is offline
     * to hide errors and completely replace the content.
     *
     * @param array $variables
     *   An associative array containing:
     *   - content - An array of page content.
     *
     * @see system_page_build()
     */
    function template_preprocess_maintenance_page(&$variables) {
      $language_interface = \Drupal::languageManager()->getCurrentLanguage();
    
      // Initializes attributes which are specific to the html element.
      $variables['html_attributes'] = new Attribute;
    
      // HTML element attributes.
      $variables['html_attributes']['lang'] = $language_interface->id;
      $variables['html_attributes']['dir'] = $language_interface->direction ? 'rtl' : 'ltr';
    
      // Add favicon
      if (theme_get_setting('features.favicon')) {
        $favicon = theme_get_setting('favicon.url');
        $type = theme_get_setting('favicon.mimetype');
        $build['#attached']['drupal_add_html_head_link'][][] = array(
          'rel' => 'shortcut icon',
          'href' => UrlHelper::stripDangerousProtocols($favicon),
          'type' => $type,
        );
        drupal_render($build);
      }
    
      foreach (system_region_list($GLOBALS['theme']) as $region_key => $region_name) {
        if (!isset($variables[$region_key])) {
          $variables[$region_key] = array();
        }
        // Append region content set with drupal_add_region_content() as markup.
        if ($region_content = drupal_get_region_content($region_key)) {
          $variables[$region_key][]['#markup'] = $region_content;
        }
      }
    
      // Setup layout variable.
      $variables['layout'] = 'none';
      if (!empty($variables['sidebar_first'])) {
        $variables['layout'] = 'first';
      }
      if (!empty($variables['sidebar_second'])) {
        $variables['layout'] = ($variables['layout'] == 'first') ? 'both' : 'second';
      }
    
      $site_config = \Drupal::config('system.site');
      $site_name = $site_config->get('name');
      $site_slogan = $site_config->get('slogan');
    
       // Construct the page title.
      if (isset($variables['page']['#title'])) {
        $head_title = array(
          'title' => strip_tags($variables['page']['#title']),
          'name' => String::checkPlain($site_config->get('name')),
        );
      }
      else {
        $head_title = array('name' => String::checkPlain($site_name));
        if ($site_slogan) {
          $head_title['slogan'] = strip_tags(filter_xss_admin($site_slogan));
        }
      }
    
      // These are usually added from system_page_build() except maintenance.css.
      // When the database is inactive it's not called so we add it here.
      $default_css['library'][] = 'core/normalize';
      $default_css['library'][] = 'system/maintenance';
      $attached = array('#attached' => $default_css);
      drupal_render($attached);
      $variables['messages'] = array(
        '#theme' => 'status_messages',
        '#access' => $variables['show_messages'],
      );
    
      $variables['head_title_array']  = $head_title;
      $variables['head_title']        = implode(' | ', $head_title);
      $variables['front_page']        = url();
      $variables['help']              = '';
      $variables['language']          = $language_interface;
      $variables['logo']              = theme_get_setting('logo.url');
      $variables['site_name']         = (theme_get_setting('features.name') ? String::checkPlain($site_name) : '');
      $variables['site_slogan']       = (theme_get_setting('features.slogan') ? filter_xss_admin($site_slogan) : '');
    
      // Compile a list of classes that are going to be applied to the body element.
      $variables['attributes']['class'][] = 'maintenance-page';
      $variables['attributes']['class'][] = 'in-maintenance';
      if (isset($variables['db_is_active']) && !$variables['db_is_active']) {
        $variables['attributes']['class'][] = 'db-offline';
      }
      if ($variables['layout'] == 'both') {
        $variables['attributes']['class'][] = 'two-sidebars';
      }
      elseif ($variables['layout'] == 'none') {
        $variables['attributes']['class'][] = 'no-sidebars';
      }
      else {
        $variables['attributes']['class'][] = 'one-sidebar';
        $variables['attributes']['class'][] = 'sidebar-' . $variables['layout'];
      }
    
      $variables['head'] = drupal_get_html_head();
    
      // While this code is used in the installer, the language module may not be
      // enabled yet (even maybe no database set up yet), but an RTL language
      // selected should result in RTL stylesheets loaded properly already.
      $css = _drupal_add_css();
      include_once DRUPAL_ROOT . '/core/modules/language/language.module';
      // Wrapping drupal_get_css() and drupal_get_js() in an object so they can
      // be called when printed.
      $variables['styles'] = new RenderWrapper('drupal_get_css', array($css));
      $variables['scripts'] = new RenderWrapper('drupal_get_js');
    
      // Allow the page to define a title.
      if (isset($variables['page']['#title'])) {
        $variables['title'] = $variables['page']['#title'];
      }
    }
    
    /**
     * Prepares variables for install page templates.
     *
     * Default template: install-page.html.twig.
     *
     * The variables array generated here is a mirror of
     * template_preprocess_page(). This preprocessor will run its course when
     * theme_install_page() is invoked.
     *
     * @param array $variables
     *   An associative array containing:
     *   - content - An array of page content.
     *
     * @see template_preprocess_maintenance_page()
     *
     */
    function template_preprocess_install_page(&$variables) {
      template_preprocess_maintenance_page($variables);
      $variables['attributes']['class'][] = 'install-page';
      // Override the site name that is displayed on the page, since Drupal is
      // still in the process of being installed.
      $distribution_name = String::checkPlain(drupal_install_profile_distribution_name());
      $variables['site_name'] = $distribution_name;
      $variables['head_title_array']['name'] = $distribution_name;
    
      $variables['head_title'] = implode(' | ', $variables['head_title_array']);
    }
    
    /**
     * Prepares variables for region templates.
     *
     * Default template: region.html.twig.
     *
     * Prepares the values passed to the theme_region function to be passed into a
     * pluggable template engine. Uses the region name to generate a template file
     * suggestions.
     *
     * @param array $variables
     *   An associative array containing:
     *   - elements: An associative array containing properties of the region.
     */
    function template_preprocess_region(&$variables) {
      // Create the $content variable that templates expect.
      $variables['content'] = $variables['elements']['#children'];
      $variables['region'] = $variables['elements']['#region'];
    
      $variables['attributes']['class'][] = 'region';
      $variables['attributes']['class'][] = drupal_html_class('region-' . $variables['region']);
    }
    
    /**
     * Provides theme registration for themes across .inc files.
     */
    function drupal_common_theme() {
      return array(
        // From theme.inc.
        'html' => array(
          'variables' => array('page_object' => NULL),
          'template' => 'html',
        ),
        'page' => array(
          'render element' => 'page',
          'template' => 'page',
        ),
        'region' => array(
          'render element' => 'elements',
          'template' => 'region',
        ),
        'datetime' => array(
          'variables' => array('timestamp' => NULL, 'text' => NULL, 'attributes' => array(), 'html' => FALSE),
          'template' => 'datetime',
        ),
        'status_messages' => array(
          'variables' => array('display' => NULL),
          'template' => 'status-messages',
        ),
        'links' => array(
          'variables' => array('links' => array(), 'attributes' => array('class' => array('links')), 'heading' => array(), 'set_active_class' => FALSE),
          'template' => 'links',
        ),
        'dropbutton_wrapper' => array(
          'variables' => array('children' => NULL),
          'template' => 'dropbutton-wrapper',
        ),
        'image' => array(
          // HTML 4 and XHTML 1.0 always require an alt attribute. The HTML 5 draft
          // allows the alt attribute to be omitted in some cases. Therefore,
          // default the alt attribute to an empty string, but allow code calling
          // _theme('image') to pass explicit NULL for it to be omitted. Usually,
          // neither omission nor an empty string satisfies accessibility
          // requirements, so it is strongly encouraged for code calling
          // _theme('image') to pass a meaningful value for the alt variable.
          // - http://www.w3.org/TR/REC-html40/struct/objects.html#h-13.8
          // - http://www.w3.org/TR/xhtml1/dtds.html
          // - http://dev.w3.org/html5/spec/Overview.html#alt
          // The title attribute is optional in all cases, so it is omitted by
          // default.
          'variables' => array('uri' => NULL, 'width' => NULL, 'height' => NULL, 'alt' => '', 'title' => NULL, 'attributes' => array()),
        ),
        'breadcrumb' => array(
          'variables' => array('breadcrumb' => NULL),
          'template' => 'breadcrumb',
        ),
        'table' => array(
          'variables' => array('header' => NULL, 'rows' => NULL, 'attributes' => array(), 'caption' => NULL, 'colgroups' => array(), 'sticky' => FALSE, 'responsive' => TRUE, 'empty' => ''),
        ),
        'tablesort_indicator' => array(
          'variables' => array('style' => NULL),
          'template' => 'tablesort-indicator',
        ),
        'mark' => array(
          'variables' => array('status' => MARK_NEW),
        ),
        'item_list' => array(
          'variables' => array('items' => array(), 'title' => '', 'list_type' => 'ul', 'attributes' => array(), 'empty' => NULL),
          'template' => 'item-list',
        ),
        'feed_icon' => array(
          'variables' => array('url' => NULL, 'title' => NULL),
          'template' => 'feed-icon',
        ),
        'more_link' => array(
          'variables' => array('url' => NULL, 'title' => NULL)
        ),
        'progress_bar' => array(
          'variables' => array('label' => NULL, 'percent' => NULL, 'message' => NULL),
          'template' => 'progress-bar',
        ),
        'indentation' => array(
          'variables' => array('size' => 1),
        ),
        // From theme.maintenance.inc.
        'maintenance_page' => array(
          'variables' => array('content' => NULL, 'show_messages' => TRUE, 'page' => array()),
          'template' => 'maintenance-page',
        ),
        'install_page' => array(
          'variables' => array('content' => NULL, 'show_messages' => TRUE, 'page' => array()),
          'template' => 'install-page',
        ),
        'task_list' => array(
          'variables' => array('items' => NULL, 'active' => NULL,  'variant' => NULL),
        ),
        'authorize_message' => array(
          'variables' => array('message' => NULL, 'success' => TRUE),
        ),
        'authorize_report' => array(
          'variables' => array('messages' => array()),
        ),
        // From pager.inc.
        'pager' => array(
          'variables' => array('tags' => array(), 'element' => 0, 'parameters' => array(), 'quantity' => 9),
          'template' => 'pager',
        ),
        // From menu.inc.
        'menu_link' => array(
          'render element' => 'element',
        ),
        'menu_tree' => array(
          'render element' => 'tree',
        ),
        'menu_local_task' => array(
          'render element' => 'element',
        ),
        'menu_local_action' => array(
          'render element' => 'element',
        ),
        'menu_local_tasks' => array(
          'variables' => array('primary' => array(), 'secondary' => array()),
        ),
        // From form.inc.
        'input' => array(
          'render element' => 'element',
        ),
        'select' => array(
          'render element' => 'element',
          'template' => 'select',
        ),
        'fieldset' => array(
          'render element' => 'element',
          'template' => 'fieldset',
        ),
        'details' => array(
          'render element' => 'element',
          'template' => 'details',
        ),
        'radios' => array(
          'render element' => 'element',
        ),
        'date' => array(
          'render element' => 'element',
        ),
        'checkboxes' => array(
          'render element' => 'element',
        ),
        'form' => array(
          'render element' => 'element',
          'template' => 'form',
        ),
        'textarea' => array(
          'render element' => 'element',
          'template' => 'textarea',
        ),
        'tableselect' => array(
          'render element' => 'element',
        ),
        'form_element' => array(
          'render element' => 'element',
          'template' => 'form-element',
        ),
        'form_required_marker' => array(
          'render element' => 'element',
        ),
        'form_element_label' => array(
          'render element' => 'element',
        ),
        'vertical_tabs' => array(
          'render element' => 'element',
          'template' => 'vertical-tabs',
        ),
        'container' => array(
          'render element' => 'element',
          'template' => 'container',
        ),
      );
    }