queue stream window updates directly from stream.Read

By queueing receive window updates directly from stream.Read, it is no
longer necessary to ask every stream for window updates when sending a
packet.

window_update_queue.go

@@ -0,0 +1,40 @@
+package quic
+
+import (
+	"sync"
+
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/wire"
+)
+
+type windowUpdateQueue struct {
+	mutex sync.Mutex
+
+	queue    map[protocol.StreamID]protocol.ByteCount
+	callback func(wire.Frame)
+}
+
+func newWindowUpdateQueue(cb func(wire.Frame)) *windowUpdateQueue {
+	return &windowUpdateQueue{
+		queue:    make(map[protocol.StreamID]protocol.ByteCount),
+		callback: cb,
+	}
+}
+
+func (q *windowUpdateQueue) Add(stream protocol.StreamID, offset protocol.ByteCount) {
+	q.mutex.Lock()
+	q.queue[stream] = offset
+	q.mutex.Unlock()
+}
+
+func (q *windowUpdateQueue) QueueAll() {
+	q.mutex.Lock()
+	for stream, offset := range q.queue {
+		q.callback(&wire.MaxStreamDataFrame{
+			StreamID:   stream,
+			ByteOffset: offset,
+		})
+		delete(q.queue, stream)
+	}
+	q.mutex.Unlock()
+}