Method cancel

Lib/asyncio/futures.py:156–169

Cancel the future and schedule callbacks. If the future is already done or cancelled, return False. Otherwise, change the future's state to cancelled, schedule the callbacks and return True.

(self, msg=None)

        return exc

    def cancel(self, msg=None):
        """Cancel the future and schedule callbacks.

        If the future is already done or cancelled, return False.  Otherwise,
        change the future's state to cancelled, schedule the callbacks and
        return True.
        """
        self.__log_traceback = False
        if self._state != _PENDING:
            return False
        self._state = _CANCELLED
        self._cancel_message = msg
        self.__schedule_callbacks()
        return True

    def __schedule_callbacks(self):
        """Internal: Ask the event loop to call all callbacks.