implement a datagram queue

datagram_queue.go

@@ -0,0 +1,51 @@
+package quic
+
+import (
+	"sync"
+
+	"github.com/lucas-clemente/quic-go/internal/wire"
+)
+
+type datagramQueue struct {
+	mutex sync.Mutex
+	queue chan *wire.DatagramFrame
+
+	closeErr error
+	closed   chan struct{}
+
+	hasData func()
+}
+
+func newDatagramQueue(hasData func()) *datagramQueue {
+	return &datagramQueue{
+		queue:   make(chan *wire.DatagramFrame),
+		hasData: hasData,
+		closed:  make(chan struct{}),
+	}
+}
+
+// AddAndWait queues a new DATAGRAM frame.
+// It blocks until the frame has been dequeued.
+func (h *datagramQueue) AddAndWait(f *wire.DatagramFrame) error {
+	h.hasData()
+	select {
+	case h.queue <- f:
+		return nil
+	case <-h.closed:
+		return h.closeErr
+	}
+}
+
+func (h *datagramQueue) Get() *wire.DatagramFrame {
+	select {
+	case f := <-h.queue:
+		return f
+	default:
+		return nil
+	}
+}
+
+func (h *datagramQueue) CloseWithError(e error) {
+	h.closeErr = e
+	close(h.closed)
+}