www.aleph1.co.uk Git - yaffs-website/blob - web/core/lib/Drupal/Core/Theme/ThemeNegotiator.php

   1 <?php
   2
   3 namespace Drupal\Core\Theme;
   4
   5 use Drupal\Core\Routing\RouteMatchInterface;
   6
   7 /**
   8  * Provides a class which determines the active theme of the page.
   9  *
  10  * It therefore uses ThemeNegotiatorInterface objects which are passed in
  11  * using the 'theme_negotiator' tag.
  12  */
  13 class ThemeNegotiator implements ThemeNegotiatorInterface {
  14
  15   /**
  16    * Holds arrays of theme negotiators, keyed by priority.
  17    *
  18    * @var array
  19    */
  20   protected $negotiators = [];
  21
  22   /**
  23    * Holds the array of theme negotiators sorted by priority.
  24    *
  25    * Set to NULL if the array needs to be re-calculated.
  26    *
  27    * @var array|null
  28    */
  29   protected $sortedNegotiators;
  30
  31   /**
  32    * The access checker for themes.
  33    *
  34    * @var \Drupal\Core\Theme\ThemeAccessCheck
  35    */
  36   protected $themeAccess;
  37
  38   /**
  39    * Constructs a new ThemeNegotiator.
  40    *
  41    * @param \Drupal\Core\Theme\ThemeAccessCheck $theme_access
  42    *   The access checker for themes.
  43    */
  44   public function __construct(ThemeAccessCheck $theme_access) {
  45     $this->themeAccess = $theme_access;
  46   }
  47
  48   /**
  49    * Adds a active theme negotiation service.
  50    *
  51    * @param \Drupal\Core\Theme\ThemeNegotiatorInterface $negotiator
  52    *   The theme negotiator to add.
  53    * @param int $priority
  54    *   Priority of the theme negotiator.
  55    */
  56   public function addNegotiator(ThemeNegotiatorInterface $negotiator, $priority) {
  57     $this->negotiators[$priority][] = $negotiator;
  58     // Force the negotiators to be re-sorted.
  59     $this->sortedNegotiators = NULL;
  60   }
  61
  62   /**
  63    * Returns the sorted array of theme negotiators.
  64    *
  65    * @return array|\Drupal\Core\Theme\ThemeNegotiatorInterface[]
  66    *   An array of theme negotiator objects.
  67    */
  68   protected function getSortedNegotiators() {
  69     if (!isset($this->sortedNegotiators)) {
  70       // Sort the negotiators according to priority.
  71       krsort($this->negotiators);
  72       // Merge nested negotiators from $this->negotiators into
  73       // $this->sortedNegotiators.
  74       $this->sortedNegotiators = [];
  75       foreach ($this->negotiators as $builders) {
  76         $this->sortedNegotiators = array_merge($this->sortedNegotiators, $builders);
  77       }
  78     }
  79     return $this->sortedNegotiators;
  80   }
  81
  82   /**
  83    * {@inheritdoc}
  84    */
  85   public function applies(RouteMatchInterface $route_match) {
  86     return TRUE;
  87   }
  88
  89   /**
  90    * {@inheritdoc}
  91    */
  92   public function determineActiveTheme(RouteMatchInterface $route_match) {
  93     foreach ($this->getSortedNegotiators() as $negotiator) {
  94       if ($negotiator->applies($route_match)) {
  95         $theme = $negotiator->determineActiveTheme($route_match);
  96         if ($theme !== NULL && $this->themeAccess->checkAccess($theme)) {
  97           return $theme;
  98         }
  99       }
 100     }
 101   }
 102
 103 }