Turba::setPreferredSortOrder PHP Method

    public static function setPreferredSortOrder(Horde_Variables $vars, $source)
    {
        if (!strlen($sortby = $vars->get('sortby'))) {
            return;
        }
        $sources = self::getColumns();
        $columns = isset($sources[$source]) ? $sources[$source] : array();
        $column_name = self::getColumnName($sortby, $columns);
        $append = true;
        $ascending = $vars->get('sortdir') == 0;
        if ($vars->get('sortadd')) {
            $sortorder = self::getPreferredSortOrder();
            foreach ($sortorder as $i => $elt) {
                if ($elt['field'] == $column_name) {
                    $sortorder[$i]['ascending'] = $ascending;
                    $append = false;
                }
            }
        } else {
            $sortorder = array();
        }
        if ($append) {
            $sortorder[] = array('ascending' => $ascending, 'field' => $column_name);
        }
        $GLOBALS['prefs']->setValue('sortorder', serialize($sortorder));
    }

             break;
         }
         if (!strlen($criteria)) {
             /* Searching all fields in basic search. */
             $criteria = array_combine(array_filter(array_keys($allCriteria[$source])), array_fill(0, count($allCriteria[$source]) - 1, $val));
         } else {
             $criteria = array($criteria => $val);
         }
         $do_search = true;
         break;
     case 'duplicate':
         $do_search = $vars->search || $vars->dupe || count($addressBooks) == 1;
         break;
 }
 /* Check for updated sort criteria */
 Turba::setPreferredSortOrder($vars, $source);
 /* Only try to perform a search if we actually have search criteria. */
 if ($do_search) {
     if ($vars->save_vbook) {
         try {
             $session->checkToken($vars->token);
         } catch (Horde_Exception $e) {
             $notification->push($e);
             Horde::url('search.php', true)->redirect();
         }
         /* We create the vbook and redirect before we try to search
          * since we are not displaying the search results on this page
          * anyway. */
         $vname = $vars->vbook_name;
         if (empty($vname)) {
             $notification->push(_("You must provide a name for virtual address books."), 'horde.error');