use a Peek / Pop API for the datagram queue (#3582)

datagram_queue_test.go

@@ -3,7 +3,6 @@ package quic
 import (
 	"errors"
 
-	"github.com/lucas-clemente/quic-go/internal/protocol"
 	"github.com/lucas-clemente/quic-go/internal/utils"
 	"github.com/lucas-clemente/quic-go/internal/wire"
 
@@ -17,15 +16,12 @@ var _ = Describe("Datagram Queue", func() {
 
 	BeforeEach(func() {
 		queued = make(chan struct{}, 100)
-		queue = newDatagramQueue(func() {
-			queued <- struct{}{}
-		}, utils.DefaultLogger, protocol.Version1)
+		queue = newDatagramQueue(func() { queued <- struct{}{} }, utils.DefaultLogger)
 	})
 
 	Context("sending", func() {
 		It("returns nil when there's no datagram to send", func() {
-			Expect(queue.NextFrameSize()).To(Equal(protocol.InvalidByteCount))
-			Expect(queue.Get()).To(BeNil())
+			Expect(queue.Peek()).To(BeNil())
 		})
 
 		It("queues a datagram", func() {
@@ -39,14 +35,32 @@ var _ = Describe("Datagram Queue", func() {
 
 			Eventually(queued).Should(HaveLen(1))
 			Consistently(done).ShouldNot(BeClosed())
-			l := queue.NextFrameSize()
-			f := queue.Get()
-			Expect(l).To(Equal(f.Length(protocol.Version1)))
-			Expect(queue.NextFrameSize()).To(Equal(protocol.InvalidByteCount))
-			Expect(f).ToNot(BeNil())
+			f := queue.Peek()
 			Expect(f.Data).To(Equal([]byte("foobar")))
 			Eventually(done).Should(BeClosed())
-			Expect(queue.Get()).To(BeNil())
+			queue.Pop()
+			Expect(queue.Peek()).To(BeNil())
+		})
+
+		It("returns the same datagram multiple times, when Pop isn't called", func() {
+			sent := make(chan struct{}, 1)
+			go func() {
+				defer GinkgoRecover()
+				Expect(queue.AddAndWait(&wire.DatagramFrame{Data: []byte("foo")})).To(Succeed())
+				sent <- struct{}{}
+				Expect(queue.AddAndWait(&wire.DatagramFrame{Data: []byte("bar")})).To(Succeed())
+				sent <- struct{}{}
+			}()
+
+			Eventually(queued).Should(HaveLen(1))
+			f := queue.Peek()
+			Expect(f.Data).To(Equal([]byte("foo")))
+			Eventually(sent).Should(Receive())
+			Expect(queue.Peek()).To(Equal(f))
+			Expect(queue.Peek()).To(Equal(f))
+			queue.Pop()
+			f = queue.Peek()
+			Expect(f.Data).To(Equal([]byte("bar")))
 		})
 
 		It("closes", func() {