(function ($) {

/**

 * Shows checked and disabled checkboxes for inherited permissions.

 */

Drupal.behaviors.permissions = {

  attach: function (context) {

    var self = this;

    $('table#permissions').once('permissions', function () {

      // On a site with many roles and permissions, this behavior initially has

      // to perform thousands of DOM manipulations to inject checkboxes and hide

      // them. By detaching the table from the DOM, all operations can be

      // performed without triggering internal layout and re-rendering processes

      // in the browser.

      var $table = $(this);

      if ($table.prev().length) {

        var $ancestor = $table.prev(), method = 'after';

      }

      else {

        var $ancestor = $table.parent(), method = 'append';

      }

      $table.detach();

      // Create dummy checkboxes. We use dummy checkboxes instead of reusing

      // the existing checkboxes here because new checkboxes don't alter the

      // submitted form. If we'd automatically check existing checkboxes, the

      // permission table would be polluted with redundant entries. This

      // is deliberate, but desirable when we automatically check them.

      var $dummy = $('<input type="checkbox" class="dummy-checkbox" disabled="disabled" checked="checked" />')

        .attr('title', Drupal.t("This permission is inherited from the authenticated user role."))

        .hide();

      $('input[type=checkbox]', this).not('.rid-2, .rid-1').addClass('real-checkbox').each(function () {

        $dummy.clone().insertAfter(this);

      });

      // Initialize the authenticated user checkbox.

      $('input[type=checkbox].rid-2', this)

        .bind('click.permissions', self.toggle)

        // .triggerHandler() cannot be used here, as it only affects the first

        // element.

        .each(self.toggle);

      // Re-insert the table into the DOM.

      $ancestor[method]($table);

    });

  },

  /**

   * Toggles all dummy checkboxes based on the checkboxes' state.

   *

   * If the "authenticated user" checkbox is checked, the checked and disabled

   * checkboxes are shown, the real checkboxes otherwise.

   */

  toggle: function () {

    var authCheckbox = this, $row = $(this).closest('tr');

    // jQuery performs too many layout calculations for .hide() and .show(),

    // leading to a major page rendering lag on sites with many roles and

    // permissions. Therefore, we toggle visibility directly.

    $row.find('.real-checkbox').each(function () {

      this.style.display = (authCheckbox.checked ? 'none' : '');

    });

    $row.find('.dummy-checkbox').each(function () {

      this.style.display = (authCheckbox.checked ? '' : 'none');

    });

  }

};

})(jQuery);