selectors.py 文件源码

def select(self, timeout=None):
            if timeout is None:
                timeout = None
            elif timeout <= 0:
                timeout = 0
            else:
                # poll() has a resolution of 1 millisecond, round away from
                # zero to wait *at least* timeout seconds.
                timeout = math.ceil(timeout * 1e3)
            ready = []
            try:
                fd_event_list = self._poll.poll(timeout)
            except InterruptedError:
                return ready
            for fd, event in fd_event_list:
                events = 0
                if event & ~select.POLLIN:
                    events |= EVENT_WRITE
                if event & ~select.POLLOUT:
                    events |= EVENT_READ

                key = self._key_from_fd(fd)
                if key:
                    ready.append((key, events & key.events))
            return ready