replace ProbablyHasPacketForRetransmission with a call to MaybeQueueRTOs

fixes #261

ackhandler/interfaces.go

@@ -15,7 +15,7 @@ type SentPacketHandler interface {
 
 	GetStopWaitingFrame() *frames.StopWaitingFrame
 
-	ProbablyHasPacketForRetransmission() bool
+	MaybeQueueRTOs()
 	DequeuePacketForRetransmission() (packet *ackhandlerlegacy.Packet)
 
 	BytesInFlight() protocol.ByteCount

ackhandler/sent_packet_handler.go

@@ -262,16 +262,8 @@ func (h *sentPacketHandler) ReceivedAck(ackFrame *frames.AckFrame, withPacketNum
 	return nil
 }
 
-// ProbablyHasPacketForRetransmission returns if there is a packet queued for retransmission
-// There is one case where it gets the answer wrong:
-// if a packet has already been queued for retransmission, but a belated ACK is received for this packet, this function will return true, although the packet will not be returend for retransmission by DequeuePacketForRetransmission()
-func (h *sentPacketHandler) ProbablyHasPacketForRetransmission() bool {
-	h.maybeQueuePacketsRTO()
-	return len(h.retransmissionQueue) > 0
-}
-
 func (h *sentPacketHandler) DequeuePacketForRetransmission() *ackhandlerlegacy.Packet {
-	if !h.ProbablyHasPacketForRetransmission() {
+	if len(h.retransmissionQueue) == 0 {
 		return nil
 	}
 
@@ -310,7 +302,7 @@ func (h *sentPacketHandler) CheckForError() error {
 	return nil
 }
 
-func (h *sentPacketHandler) maybeQueuePacketsRTO() {
+func (h *sentPacketHandler) MaybeQueueRTOs() {
 	if time.Now().Before(h.TimeOfFirstRTO()) {
 		return
 	}

ackhandler/sent_packet_handler_test.go

@@ -568,7 +568,7 @@ var _ = Describe("SentPacketHandler", func() {
 				Expect(err).ToNot(HaveOccurred())
 			}
 			Expect(getPacketElement(2)).ToNot(BeNil())
-			Expect(handler.ProbablyHasPacketForRetransmission()).To(BeFalse())
+			handler.MaybeQueueRTOs()
 			Expect(handler.DequeuePacketForRetransmission()).To(BeNil())
 		})
 
@@ -578,7 +578,7 @@ var _ = Describe("SentPacketHandler", func() {
 				Expect(err).ToNot(HaveOccurred())
 			}
 			Expect(getPacketElement(2)).To(BeNil())
-			Expect(handler.ProbablyHasPacketForRetransmission()).To(BeTrue())
+			handler.MaybeQueueRTOs()
 			Expect(handler.retransmissionQueue).To(HaveLen(1))
 			Expect(handler.retransmissionQueue[0].PacketNumber).To(Equal(protocol.PacketNumber(2)))
 		})
@@ -819,7 +819,7 @@ var _ = Describe("SentPacketHandler", func() {
 			err := handler.SentPacket(&ackhandlerlegacy.Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1})
 			Expect(err).NotTo(HaveOccurred())
 			handler.lastSentPacketTime = time.Now().Add(-time.Second)
-			handler.maybeQueuePacketsRTO()
+			handler.MaybeQueueRTOs()
 			Expect(cong.nCalls).To(Equal(3))
 			// rttUpdated, bytesInFlight, ackedPackets, lostPackets
 			Expect(cong.argsOnCongestionEvent[0]).To(BeFalse())
@@ -866,7 +866,7 @@ var _ = Describe("SentPacketHandler", func() {
 			It("does nothing if not required", func() {
 				err := handler.SentPacket(&ackhandlerlegacy.Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1})
 				Expect(err).NotTo(HaveOccurred())
-				handler.maybeQueuePacketsRTO()
+				handler.MaybeQueueRTOs()
 				Expect(handler.retransmissionQueue).To(BeEmpty())
 			})
 
@@ -875,26 +875,19 @@ var _ = Describe("SentPacketHandler", func() {
 				err := handler.SentPacket(p)
 				Expect(err).NotTo(HaveOccurred())
 				handler.lastSentPacketTime = time.Now().Add(-time.Second)
-				handler.maybeQueuePacketsRTO()
+				handler.MaybeQueueRTOs()
 				Expect(handler.retransmissionQueue).To(HaveLen(1))
 				Expect(handler.retransmissionQueue[0].PacketNumber).To(Equal(p.PacketNumber))
 				Expect(time.Now().Sub(handler.lastSentPacketTime)).To(BeNumerically("<", time.Second/2))
 			})
 		})
 
-		It("works with HasPacketForRetransmission", func() {
-			p := &ackhandlerlegacy.Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1}
-			err := handler.SentPacket(p)
-			Expect(err).NotTo(HaveOccurred())
-			handler.lastSentPacketTime = time.Now().Add(-time.Second)
-			Expect(handler.DequeuePacketForRetransmission()).ToNot(BeNil())
-		})
-
 		It("works with DequeuePacketForRetransmission", func() {
 			p := &ackhandlerlegacy.Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1}
 			err := handler.SentPacket(p)
 			Expect(err).NotTo(HaveOccurred())
 			handler.lastSentPacketTime = time.Now().Add(-time.Second)
+			handler.MaybeQueueRTOs()
 			Expect(handler.DequeuePacketForRetransmission().PacketNumber).To(Equal(p.PacketNumber))
 		})
 	})