blob: 5b4f856de27d812d2b05ffbca264c36c800119a0 [file] [log] [blame]
use codec::Codec;
use frame::{self, Reason, StreamId};
use bytes::Buf;
use futures::{Async, Poll};
use std::io;
use tokio_io::AsyncWrite;
/// Manages our sending of GOAWAY frames.
pub(super) struct GoAway {
/// Whether the connection should close now, or wait until idle.
close_now: bool,
/// Records if we've sent any GOAWAY before.
going_away: Option<GoingAway>,
/// A GOAWAY frame that must be buffered in the Codec immediately.
pending: Option<frame::GoAway>,
/// Keeps a memory of any GOAWAY frames we've sent before.
/// This looks very similar to a `frame::GoAway`, but is a separate type. Why?
/// Mostly for documentation purposes. This type is to record status. If it
/// were a `frame::GoAway`, it might appear like we eventually wanted to
/// serialize it. We **only** want to be able to look up these fields at a
/// later time.
/// (Technically, `frame::GoAway` should gain an opaque_debug_data field as
/// well, and we wouldn't want to save that here to accidentally dump in logs,
/// or waste struct space.)
struct GoingAway {
/// Stores the highest stream ID of a GOAWAY that has been sent.
/// It's illegal to send a subsequent GOAWAY with a higher ID.
last_processed_id: StreamId,
/// Records the error code of any GOAWAY frame sent.
reason: Reason,
impl GoAway {
pub fn new() -> Self {
GoAway {
close_now: false,
going_away: None,
pending: None,
/// Enqueue a GOAWAY frame to be written.
/// The connection is expected to continue to run until idle.
pub fn go_away(&mut self, f: frame::GoAway) {
if let Some(ref going_away) = self.going_away {
f.last_stream_id() <= going_away.last_processed_id,
"GOAWAY stream IDs shouldn't be higher; \
last_processed_id = {:?}, f.last_stream_id() = {:?}",
self.going_away = Some(GoingAway {
last_processed_id: f.last_stream_id(),
reason: f.reason(),
self.pending = Some(f);
pub fn go_away_now(&mut self, f: frame::GoAway) {
self.close_now = true;
if let Some(ref going_away) = self.going_away {
// Prevent sending the same GOAWAY twice.
if going_away.last_processed_id == f.last_stream_id()
&& going_away.reason == f.reason() {
/// Return if a GOAWAY has ever been scheduled.
pub fn is_going_away(&self) -> bool {
/// Return the last Reason we've sent.
pub fn going_away_reason(&self) -> Option<Reason> {
.map(|g| g.reason)
/// Returns if the connection should close now, or wait until idle.
pub fn should_close_now(&self) -> bool {
self.pending.is_none() && self.close_now
/// Returns if the connection should be closed when idle.
pub fn should_close_on_idle(&self) -> bool {
!self.close_now && self.going_away
.map(|g| g.last_processed_id != StreamId::MAX)
/// Try to write a pending GOAWAY frame to the buffer.
/// If a frame is written, the `Reason` of the GOAWAY is returned.
pub fn send_pending_go_away<T, B>(&mut self, dst: &mut Codec<T, B>) -> Poll<Option<Reason>, io::Error>
T: AsyncWrite,
B: Buf,
if let Some(frame) = self.pending.take() {
if !dst.poll_ready()?.is_ready() {
self.pending = Some(frame);
return Ok(Async::NotReady);
let reason = frame.reason();
.expect("invalid GOAWAY frame");
return Ok(Async::Ready(Some(reason)));
} else if self.should_close_now() {
return Ok(Async::Ready(self.going_away_reason()));