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|
package http3
import (
"context"
"errors"
"os"
"sync"
"github.com/quic-go/quic-go"
)
const streamDatagramQueueLen = 32
// stateTrackingStream is an implementation of quic.Stream that delegates
// to an underlying stream
// it takes care of proxying send and receive errors onto an implementation of
// the errorSetter interface (intended to be occupied by a datagrammer)
// it is also responsible for clearing the stream based on its ID from its
// parent connection, this is done through the streamClearer interface when
// both the send and receive sides are closed
type stateTrackingStream struct {
*quic.Stream
sendDatagram func([]byte) error
hasData chan struct{}
queue [][]byte // TODO: use a ring buffer
mx sync.Mutex
sendErr error
recvErr error
clearer streamClearer
}
var _ datagramStream = &stateTrackingStream{}
type streamClearer interface {
clearStream(quic.StreamID)
}
func newStateTrackingStream(s *quic.Stream, clearer streamClearer, sendDatagram func([]byte) error) *stateTrackingStream {
t := &stateTrackingStream{
Stream: s,
clearer: clearer,
sendDatagram: sendDatagram,
hasData: make(chan struct{}, 1),
}
context.AfterFunc(s.Context(), func() {
t.closeSend(context.Cause(s.Context()))
})
return t
}
func (s *stateTrackingStream) closeSend(e error) {
s.mx.Lock()
defer s.mx.Unlock()
// clear the stream the first time both the send
// and receive are finished
if s.sendErr == nil {
if s.recvErr != nil {
s.clearer.clearStream(s.StreamID())
}
s.sendErr = e
}
}
func (s *stateTrackingStream) closeReceive(e error) {
s.mx.Lock()
defer s.mx.Unlock()
// clear the stream the first time both the send
// and receive are finished
if s.recvErr == nil {
if s.sendErr != nil {
s.clearer.clearStream(s.StreamID())
}
s.recvErr = e
s.signalHasDatagram()
}
}
func (s *stateTrackingStream) Close() error {
s.closeSend(errors.New("write on closed stream"))
return s.Stream.Close()
}
func (s *stateTrackingStream) CancelWrite(e quic.StreamErrorCode) {
s.closeSend(&quic.StreamError{StreamID: s.StreamID(), ErrorCode: e})
s.Stream.CancelWrite(e)
}
func (s *stateTrackingStream) Write(b []byte) (int, error) {
n, err := s.Stream.Write(b)
if err != nil && !errors.Is(err, os.ErrDeadlineExceeded) {
s.closeSend(err)
}
return n, err
}
func (s *stateTrackingStream) CancelRead(e quic.StreamErrorCode) {
s.closeReceive(&quic.StreamError{StreamID: s.StreamID(), ErrorCode: e})
s.Stream.CancelRead(e)
}
func (s *stateTrackingStream) Read(b []byte) (int, error) {
n, err := s.Stream.Read(b)
if err != nil && !errors.Is(err, os.ErrDeadlineExceeded) {
s.closeReceive(err)
}
return n, err
}
func (s *stateTrackingStream) SendDatagram(b []byte) error {
s.mx.Lock()
sendErr := s.sendErr
s.mx.Unlock()
if sendErr != nil {
return sendErr
}
return s.sendDatagram(b)
}
func (s *stateTrackingStream) signalHasDatagram() {
select {
case s.hasData <- struct{}{}:
default:
}
}
func (s *stateTrackingStream) enqueueDatagram(data []byte) {
s.mx.Lock()
defer s.mx.Unlock()
if s.recvErr != nil {
return
}
if len(s.queue) >= streamDatagramQueueLen {
return
}
s.queue = append(s.queue, data)
s.signalHasDatagram()
}
func (s *stateTrackingStream) ReceiveDatagram(ctx context.Context) ([]byte, error) {
start:
s.mx.Lock()
if len(s.queue) > 0 {
data := s.queue[0]
s.queue = s.queue[1:]
s.mx.Unlock()
return data, nil
}
if receiveErr := s.recvErr; receiveErr != nil {
s.mx.Unlock()
return nil, receiveErr
}
s.mx.Unlock()
select {
case <-ctx.Done():
return nil, context.Cause(ctx)
case <-s.hasData:
}
goto start
}
func (s *stateTrackingStream) QUICStream() *quic.Stream {
return s.Stream
}
|
