use a generic streams map for outgoing streams (#3488)

streams_map_outgoing.go

@@ -0,0 +1,230 @@
+package quic
+
+import (
+	"context"
+	"sync"
+
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/wire"
+)
+
+type outgoingStream interface {
+	updateSendWindow(protocol.ByteCount)
+	closeForShutdown(error)
+}
+
+type outgoingStreamsMap[T outgoingStream] struct {
+	mutex sync.RWMutex
+
+	streamType protocol.StreamType
+	streams    map[protocol.StreamNum]T
+
+	openQueue      map[uint64]chan struct{}
+	lowestInQueue  uint64
+	highestInQueue uint64
+
+	nextStream  protocol.StreamNum // stream ID of the stream returned by OpenStream(Sync)
+	maxStream   protocol.StreamNum // the maximum stream ID we're allowed to open
+	blockedSent bool               // was a STREAMS_BLOCKED sent for the current maxStream
+
+	newStream            func(protocol.StreamNum) T
+	queueStreamIDBlocked func(*wire.StreamsBlockedFrame)
+
+	closeErr error
+}
+
+func newOutgoingStreamsMap[T outgoingStream](
+	streamType protocol.StreamType,
+	newStream func(protocol.StreamNum) T,
+	queueControlFrame func(wire.Frame),
+) *outgoingStreamsMap[T] {
+	return &outgoingStreamsMap[T]{
+		streamType:           streamType,
+		streams:              make(map[protocol.StreamNum]T),
+		openQueue:            make(map[uint64]chan struct{}),
+		maxStream:            protocol.InvalidStreamNum,
+		nextStream:           1,
+		newStream:            newStream,
+		queueStreamIDBlocked: func(f *wire.StreamsBlockedFrame) { queueControlFrame(f) },
+	}
+}
+
+func (m *outgoingStreamsMap[T]) OpenStream() (T, error) {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	if m.closeErr != nil {
+		return *new(T), m.closeErr
+	}
+
+	// if there are OpenStreamSync calls waiting, return an error here
+	if len(m.openQueue) > 0 || m.nextStream > m.maxStream {
+		m.maybeSendBlockedFrame()
+		return *new(T), streamOpenErr{errTooManyOpenStreams}
+	}
+	return m.openStream(), nil
+}
+
+func (m *outgoingStreamsMap[T]) OpenStreamSync(ctx context.Context) (T, error) {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	if m.closeErr != nil {
+		return *new(T), m.closeErr
+	}
+
+	if err := ctx.Err(); err != nil {
+		return *new(T), err
+	}
+
+	if len(m.openQueue) == 0 && m.nextStream <= m.maxStream {
+		return m.openStream(), nil
+	}
+
+	waitChan := make(chan struct{}, 1)
+	queuePos := m.highestInQueue
+	m.highestInQueue++
+	if len(m.openQueue) == 0 {
+		m.lowestInQueue = queuePos
+	}
+	m.openQueue[queuePos] = waitChan
+	m.maybeSendBlockedFrame()
+
+	for {
+		m.mutex.Unlock()
+		select {
+		case <-ctx.Done():
+			m.mutex.Lock()
+			delete(m.openQueue, queuePos)
+			return *new(T), ctx.Err()
+		case <-waitChan:
+		}
+		m.mutex.Lock()
+
+		if m.closeErr != nil {
+			return *new(T), m.closeErr
+		}
+		if m.nextStream > m.maxStream {
+			// no stream available. Continue waiting
+			continue
+		}
+		str := m.openStream()
+		delete(m.openQueue, queuePos)
+		m.lowestInQueue = queuePos + 1
+		m.unblockOpenSync()
+		return str, nil
+	}
+}
+
+func (m *outgoingStreamsMap[T]) openStream() T {
+	s := m.newStream(m.nextStream)
+	m.streams[m.nextStream] = s
+	m.nextStream++
+	return s
+}
+
+// maybeSendBlockedFrame queues a STREAMS_BLOCKED frame for the current stream offset,
+// if we haven't sent one for this offset yet
+func (m *outgoingStreamsMap[T]) maybeSendBlockedFrame() {
+	if m.blockedSent {
+		return
+	}
+
+	var streamNum protocol.StreamNum
+	if m.maxStream != protocol.InvalidStreamNum {
+		streamNum = m.maxStream
+	}
+	m.queueStreamIDBlocked(&wire.StreamsBlockedFrame{
+		Type:        m.streamType,
+		StreamLimit: streamNum,
+	})
+	m.blockedSent = true
+}
+
+func (m *outgoingStreamsMap[T]) GetStream(num protocol.StreamNum) (T, error) {
+	m.mutex.RLock()
+	if num >= m.nextStream {
+		m.mutex.RUnlock()
+		return *new(T), streamError{
+			message: "peer attempted to open stream %d",
+			nums:    []protocol.StreamNum{num},
+		}
+	}
+	s := m.streams[num]
+	m.mutex.RUnlock()
+	return s, nil
+}
+
+func (m *outgoingStreamsMap[T]) DeleteStream(num protocol.StreamNum) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	if _, ok := m.streams[num]; !ok {
+		return streamError{
+			message: "tried to delete unknown outgoing stream %d",
+			nums:    []protocol.StreamNum{num},
+		}
+	}
+	delete(m.streams, num)
+	return nil
+}
+
+func (m *outgoingStreamsMap[T]) SetMaxStream(num protocol.StreamNum) {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	if num <= m.maxStream {
+		return
+	}
+	m.maxStream = num
+	m.blockedSent = false
+	if m.maxStream < m.nextStream-1+protocol.StreamNum(len(m.openQueue)) {
+		m.maybeSendBlockedFrame()
+	}
+	m.unblockOpenSync()
+}
+
+// UpdateSendWindow is called when the peer's transport parameters are received.
+// Only in the case of a 0-RTT handshake will we have open streams at this point.
+// We might need to update the send window, in case the server increased it.
+func (m *outgoingStreamsMap[T]) UpdateSendWindow(limit protocol.ByteCount) {
+	m.mutex.Lock()
+	for _, str := range m.streams {
+		str.updateSendWindow(limit)
+	}
+	m.mutex.Unlock()
+}
+
+// unblockOpenSync unblocks the next OpenStreamSync go-routine to open a new stream
+func (m *outgoingStreamsMap[T]) unblockOpenSync() {
+	if len(m.openQueue) == 0 {
+		return
+	}
+	for qp := m.lowestInQueue; qp <= m.highestInQueue; qp++ {
+		c, ok := m.openQueue[qp]
+		if !ok { // entry was deleted because the context was canceled
+			continue
+		}
+		// unblockOpenSync is called both from OpenStreamSync and from SetMaxStream.
+		// It's sufficient to only unblock OpenStreamSync once.
+		select {
+		case c <- struct{}{}:
+		default:
+		}
+		return
+	}
+}
+
+func (m *outgoingStreamsMap[T]) CloseWithError(err error) {
+	m.mutex.Lock()
+	m.closeErr = err
+	for _, str := range m.streams {
+		str.closeForShutdown(err)
+	}
+	for _, c := range m.openQueue {
+		if c != nil {
+			close(c)
+		}
+	}
+	m.mutex.Unlock()
+}