process.py 文件源码

def read_line(self, time_limit=None):
        """
        Read a line from the process.

        Block or wait for time_limit secs. Timeout does not work on Windows.
        """
        if self.proc is not None:
            poll_obj = select.poll()
            poll_obj.register(self.proc.stdout, select.POLLIN)
            start = time.time()
            while time_limit is None or time.time() - start < time_limit:
                poll_result = poll_obj.poll(0)
                if poll_result:
                    line = self.proc.stdout.readline().decode()
                    return line
                else:
                    time.sleep(0.05)
            raise TimeoutError()
        else:
            return None