From b38d4b37fe7936d875f212def17a4514881050e1 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Thu, 16 Jun 2016 16:05:37 +0700
Subject: [PATCH] don't count retransmission as sent bytes for connection flow
 control

---
 stream_frame_queue.go      |  5 +++--
 stream_frame_queue_test.go | 14 ++++++++++++++
 stream_test.go             |  3 +++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/stream_frame_queue.go b/stream_frame_queue.go
index 284ee49b..ae00220e 100644
--- a/stream_frame_queue.go
+++ b/stream_frame_queue.go
@@ -148,8 +148,9 @@ func (q *streamFrameQueue) Pop(maxLength protocol.ByteCount) (*frames.StreamFram
 
 	q.byteLen -= frame.DataLen()
 
-	// TODO: don't add retransmission to connection-level flow control
-	q.flowControlManager.AddBytesSent(streamID, frame.DataLen())
+	if !isPrioFrame {
+		q.flowControlManager.AddBytesSent(streamID, frame.DataLen())
+	}
 
 	q.len--
 	return frame, nil
diff --git a/stream_frame_queue_test.go b/stream_frame_queue_test.go
index 6b2553df..34db38cd 100644
--- a/stream_frame_queue_test.go
+++ b/stream_frame_queue_test.go
@@ -220,6 +220,20 @@ var _ = Describe("streamFrameQueue", func() {
 			Expect(frame).To(BeNil())
 		})
 
+		It("tells the FlowControlManager how many bytes it sent", func() {
+			queue.Push(frame1, false)
+			_, err := queue.Pop(1000)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(queue.flowControlManager.(*mockFlowControlHandler).bytesSent).To(Equal(frame1.DataLen()))
+		})
+
+		It("doesn't add the bytes sent to the FlowControlManager if it was a retransmission", func() {
+			queue.Push(prioFrame1, true)
+			_, err := queue.Pop(1000)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(queue.flowControlManager.(*mockFlowControlHandler).bytesSent).To(BeZero())
+		})
+
 		It("returns normal frames if no prio frames are available", func() {
 			queue.Push(frame1, false)
 			queue.Push(frame2, false)
diff --git a/stream_test.go b/stream_test.go
index a1395981..3f284cba 100644
--- a/stream_test.go
+++ b/stream_test.go
@@ -46,6 +46,7 @@ type mockFlowControlHandler struct {
 	remainingConnectionWindowSize protocol.ByteCount
 	bytesReadForStream            protocol.StreamID
 	bytesRead                     protocol.ByteCount
+	bytesSent                     protocol.ByteCount
 
 	highestReceivedForStream protocol.StreamID
 	highestReceived          protocol.ByteCount
@@ -85,8 +86,10 @@ func (m *mockFlowControlHandler) UpdateHighestReceived(streamID protocol.StreamI
 }
 
 func (m *mockFlowControlHandler) AddBytesSent(streamID protocol.StreamID, n protocol.ByteCount) error {
+	m.bytesSent += n
 	return nil
 }
+
 func (m *mockFlowControlHandler) SendWindowSize(streamID protocol.StreamID) (protocol.ByteCount, error) {
 	return m.sendWindowSizes[streamID], nil
 }