original_string: public function execute() {
          global $CFG, $DB;
          require_once($CFG->dirroot . '/mod/chat/lib.php');
  
          chat_update_chat_times();
          chat_delete_old_users();
  
          $timenow = time();
          $subselect = "SELECT c.keepdays
                          FROM {chat} c
                         WHERE c.id = {chat_messages}.chatid";
          $DB->delete_records_select('chat_messages', "($subselect) > 0 AND timestamp < (? - ($subselect) * ?)",
                  [$timenow, DAYSECS]);
  
          $DB->delete_records_select('chat_messages_current', "timestamp < ?", [$timenow - 8 * HOURSECS]);
      }
code: public function execute() {
          global $CFG, $DB;
          require_once($CFG->dirroot . '/mod/chat/lib.php');
  
          chat_update_chat_times();
          chat_delete_old_users();
  
          $timenow = time();
          $subselect = "SELECT c.keepdays
                          FROM {chat} c
                         WHERE c.id = {chat_messages}.chatid";
          $DB->delete_records_select('chat_messages', "($subselect) > 0 AND timestamp < (? - ($subselect) * ?)",
                  [$timenow, DAYSECS]);
  
          $DB->delete_records_select('chat_messages_current', "timestamp < ?", [$timenow - 8 * HOURSECS]);
      }
code_tokens: public function execute ( ) { global $ CFG , $ DB ; require_once ( $ CFG -> dirroot . '/mod/chat/lib.php' ) ; chat_update_chat_times ( ) ; chat_delete_old_users ( ) ; $ timenow = time ( ) ; $ subselect = "SELECT c.keepdays
                          FROM {chat} c
                         WHERE c.id = {chat_messages}.chatid" ; $ DB -> delete_records_select ( 'chat_messages' , "($subselect) > 0 AND timestamp < (? - ($subselect) * ?)" , [ $ timenow , DAYSECS ] ) ; $ DB -> delete_records_select ( 'chat_messages_current' , "timestamp < ?" , [ $ timenow - 8 * HOURSECS ] ) ; }
docstring: Run chat cron.
docstring_tokens: Run chat cron .