threads.py 文件源码

def __await__(self):
        def exec_when_ready():
            event.wait()
            coro.send(None)

            if not self.exited:
                raise RuntimeError('attempted to "await" in a worker thread')

        if self.exited:
            # This is run in the worker thread
            yield
        else:
            # This is run in the event loop thread
            previous_frame = inspect.currentframe().f_back
            coro = next(obj for obj in gc.get_referrers(previous_frame.f_code)
                        if inspect.iscoroutine(obj) and obj.cr_frame is previous_frame)
            event = Event()
            loop = get_event_loop()
            future = loop.run_in_executor(self.executor, exec_when_ready)
            next(future.__await__())  # Make the future think it's being awaited on
            loop.call_soon(event.set)
            yield future