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tokio-xmpp: Poll packets in a loop

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This needs to be a loop in order to ignore packets we don’t care about,
or those we want to handle elsewhere.  Returning something isn’t correct
in those two cases because it would signal to tokio that the XMPPStream
is also done, while there could be additional packets waiting for us.

The proper solution is thus a loop which we exit once we have something
to return.

Fixes a deadlock when we ignore some packets.
This commit is contained in:
Emmanuel Gil Peyrot 2023-06-21 13:43:24 +02:00 • committed by pep
commit 6ccc5ccace
1 changed files with 44 additions and 36 deletions
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26
tokio-xmpp/src/client/async_client.rs
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@ -243,42 +243,50 @@ impl Stream for Client {
}; };
// Poll stream // Poll stream
//
// This needs to be a loop in order to ignore packets we don’t care about, or those
// we want to handle elsewhere. Returning something isn’t correct in those two
// cases because it would signal to tokio that the XMPPStream is also done, while
// there could be additional packets waiting for us.
//
// The proper solution is thus a loop which we exit once we have something to
// return.
loop {
match Pin::new(&mut stream).poll_next(cx) { match Pin::new(&mut stream).poll_next(cx) {
Poll::Ready(None) => { Poll::Ready(None) => {
// EOF // EOF
self.state = ClientState::Disconnected; self.state = ClientState::Disconnected;
Poll::Ready(Some(Event::Disconnected(Error::Disconnected))) return Poll::Ready(Some(Event::Disconnected(Error::Disconnected)));
} }
Poll::Ready(Some(Ok(Packet::Stanza(stanza)))) => { Poll::Ready(Some(Ok(Packet::Stanza(stanza)))) => {
// Receive stanza // Receive stanza
self.state = ClientState::Connected(stream); self.state = ClientState::Connected(stream);
Poll::Ready(Some(Event::Stanza(stanza))) return Poll::Ready(Some(Event::Stanza(stanza)));
} }
Poll::Ready(Some(Ok(Packet::Text(_)))) => { Poll::Ready(Some(Ok(Packet::Text(_)))) => {
// Ignore text between stanzas // Ignore text between stanzas
self.state = ClientState::Connected(stream);
Poll::Pending
} }
Poll::Ready(Some(Ok(Packet::StreamStart(_)))) => { Poll::Ready(Some(Ok(Packet::StreamStart(_)))) => {
// <stream:stream> // <stream:stream>
self.state = ClientState::Disconnected; self.state = ClientState::Disconnected;
Poll::Ready(Some(Event::Disconnected( return Poll::Ready(Some(Event::Disconnected(
ProtocolError::InvalidStreamStart.into(), ProtocolError::InvalidStreamStart.into(),
))) )));
} }
Poll::Ready(Some(Ok(Packet::StreamEnd))) => { Poll::Ready(Some(Ok(Packet::StreamEnd))) => {
// End of stream: </stream:stream> // End of stream: </stream:stream>
self.state = ClientState::Disconnected; self.state = ClientState::Disconnected;
Poll::Ready(Some(Event::Disconnected(Error::Disconnected))) return Poll::Ready(Some(Event::Disconnected(Error::Disconnected)));
} }
Poll::Pending => { Poll::Pending => {
// Try again later // Try again later
self.state = ClientState::Connected(stream); self.state = ClientState::Connected(stream);
Poll::Pending return Poll::Pending;
} }
Poll::Ready(Some(Err(e))) => { Poll::Ready(Some(Err(e))) => {
self.state = ClientState::Disconnected; self.state = ClientState::Disconnected;
Poll::Ready(Some(Event::Disconnected(e.into()))) return Poll::Ready(Some(Event::Disconnected(e.into())));
}
} }
} }
} }