FilterAccessCheck.php

<?php

/**
 * @file
 * Contains \Drupal\filter\Access\FilterAccessCheck.
 */
namespace Drupal\filter\Access;

use Drupal\Core\Access\AccessCheckInterface;
use Symfony\Component\Routing\Route;
use Symfony\Component\HttpFoundation\Request;

/**
 * Checks access for text formats.
 */
class FilterAccessCheck implements AccessCheckInterface {

  /**
   * {@inheritdoc}
   */
  public function applies(Route $route) {
    return array_key_exists('_filter_access', $route
      ->getRequirements());
  }

  /**
   * {@inheritdoc}
   */
  public function access(Route $route, Request $request) {
    if ($format = $request->attributes
      ->get('filter_format')) {

      // Handle special cases up front. All users have access to the fallback
      // format.
      if ($format->format == filter_fallback_format()) {
        return TRUE;
      }

      // Check the permission if one exists; otherwise, we have a non-existent
      // format so we return FALSE.
      $permission = filter_permission_name($format);
      return !empty($permission) && user_access($permission);
    }
  }

}