Method _add_writer

Lib/asyncio/selector_events.py:312–325

(self, fd, callback, *args)

            return False

    def _add_writer(self, fd, callback, *args):
        self._check_closed()
        handle = events.Handle(callback, args, self, None)
        key = self._selector.get_map().get(fd)
        if key is None:
            self._selector.register(fd, selectors.EVENT_WRITE,
                                    (None, handle))
        else:
            mask, (reader, writer) = key.events, key.data
            self._selector.modify(fd, mask | selectors.EVENT_WRITE,
                                  (reader, handle))
            if writer is not None:
                writer.cancel()
        return handle

    def _remove_writer(self, fd):
        """Remove a writer callback."""