query.py 文件源码

def _wait_for(ir, iw, ix, expiration):
    done = False
    while not done:
        if expiration is None:
            timeout = None
        else:
            timeout = expiration - time.time()
            if timeout <= 0.0:
                raise dns.exception.Timeout
        try:
            if timeout is None:
                (r, w, x) = select.select(ir, iw, ix)
            else:
                (r, w, x) = select.select(ir, iw, ix, timeout)
        except select.error, e:
            if e.args[0] != errno.EINTR:
                raise e
        done = True
        if len(r) == 0 and len(w) == 0 and len(x) == 0:
            raise dns.exception.Timeout