From 5768b492d76303af7a90aa69b798433a587614f7 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Wed, 31 Oct 2018 10:05:29 +0700
Subject: [PATCH] introduce a type for unidirctional and bidirectional streams

---
 internal/protocol/stream_id.go      | 19 ++++++++++++++++---
 internal/protocol/stream_id_test.go |  8 ++++----
 session.go                          |  2 +-
 3 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/internal/protocol/stream_id.go b/internal/protocol/stream_id.go
index 49c4df7e..0e0ab7e9 100644
--- a/internal/protocol/stream_id.go
+++ b/internal/protocol/stream_id.go
@@ -3,6 +3,16 @@ package protocol
 // A StreamID in QUIC
 type StreamID uint64
 
+// StreamType encodes if this is a unidirectional or bidirectional stream
+type StreamType uint8
+
+const (
+	// StreamTypeUni is a unidirectional stream
+	StreamTypeUni StreamType = iota
+	// StreamTypeBidi is a bidirectional stream
+	StreamTypeBidi
+)
+
 // InitiatedBy says if the stream was initiated by the client or by the server
 func (s StreamID) InitiatedBy() Perspective {
 	if s%2 == 0 {
@@ -11,9 +21,12 @@ func (s StreamID) InitiatedBy() Perspective {
 	return PerspectiveServer
 }
 
-// IsUniDirectional says if this is a unidirectional stream (true) or not (false)
-func (s StreamID) IsUniDirectional() bool {
-	return s%4 >= 2
+//Type says if this is a unidirectional or bidirectional stream
+func (s StreamID) Type() StreamType {
+	if s%4 >= 2 {
+		return StreamTypeUni
+	}
+	return StreamTypeBidi
 }
 
 // MaxBidiStreamID is the highest stream ID that the peer is allowed to open,
diff --git a/internal/protocol/stream_id_test.go b/internal/protocol/stream_id_test.go
index 72adac35..e19823d3 100644
--- a/internal/protocol/stream_id_test.go
+++ b/internal/protocol/stream_id_test.go
@@ -14,10 +14,10 @@ var _ = Describe("Stream ID", func() {
 	})
 
 	It("tells the directionality", func() {
-		Expect(StreamID(4).IsUniDirectional()).To(BeFalse())
-		Expect(StreamID(5).IsUniDirectional()).To(BeFalse())
-		Expect(StreamID(6).IsUniDirectional()).To(BeTrue())
-		Expect(StreamID(7).IsUniDirectional()).To(BeTrue())
+		Expect(StreamID(4).Type()).To(Equal(StreamTypeBidi))
+		Expect(StreamID(5).Type()).To(Equal(StreamTypeBidi))
+		Expect(StreamID(6).Type()).To(Equal(StreamTypeUni))
+		Expect(StreamID(7).Type()).To(Equal(StreamTypeUni))
 	})
 
 	Context("maximum stream IDs", func() {
diff --git a/session.go b/session.go
index d6a2716b..12e164fc 100644
--- a/session.go
+++ b/session.go
@@ -992,7 +992,7 @@ func (s *session) newStream(id protocol.StreamID) streamI {
 func (s *session) newFlowController(id protocol.StreamID) flowcontrol.StreamFlowController {
 	var initialSendWindow protocol.ByteCount
 	if s.peerParams != nil {
-		if id.IsUniDirectional() {
+		if id.Type() == protocol.StreamTypeUni {
 			initialSendWindow = s.peerParams.InitialMaxStreamDataUni
 		} else {
 			if id.InitiatedBy() == s.perspective {