add method to FlowControlManager to tell if Stream contribues to connection-level flow control

flowcontrol/flow_control_manager.go

@@ -167,6 +167,17 @@ func (f *flowControlManager) UpdateWindow(streamID protocol.StreamID, offset pro
 	return streamFlowController.UpdateSendWindow(offset), nil
 }
 
+func (f *flowControlManager) StreamContributesToConnectionFlowControl(streamID protocol.StreamID) (bool, error) {
+	f.mutex.Lock()
+	defer f.mutex.Unlock()
+
+	contributes, ok := f.contributesToConnectionFlowControl[streamID]
+	if !ok {
+		return false, errMapAccess
+	}
+	return contributes, nil
+}
+
 func (f *flowControlManager) getFlowController(streamID protocol.StreamID) (FlowController, error) {
 	streamFlowController, ok := f.streamFlowController[streamID]
 	if !ok {

flowcontrol/flow_control_manager_test.go

@@ -171,5 +171,26 @@ var _ = Describe("Flow Control Manager", func() {
 				Expect(size).To(Equal(protocol.ByteCount(0x1000)))
 			})
 		})
+
+		Context("streams contributing to connection-level flow control", func() {
+			It("says that a stream contributes", func() {
+				fcm.NewStream(5, true)
+				contributes, err := fcm.StreamContributesToConnectionFlowControl(5)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(contributes).To(BeTrue())
+			})
+
+			It("says that a stream doesn't contribute", func() {
+				fcm.NewStream(3, false)
+				contributes, err := fcm.StreamContributesToConnectionFlowControl(3)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(contributes).To(BeFalse())
+			})
+
+			It("returns an error for an unknown stream", func() {
+				_, err := fcm.StreamContributesToConnectionFlowControl(1337)
+				Expect(err).To(HaveOccurred())
+			})
+		})
 	})
 })

flowcontrol/interface.go

@@ -29,4 +29,5 @@ type FlowControlManager interface {
 	SendWindowSize(streamID protocol.StreamID) (protocol.ByteCount, error)
 	RemainingConnectionWindowSize() protocol.ByteCount
 	UpdateWindow(streamID protocol.StreamID, offset protocol.ByteCount) (bool, error)
+	StreamContributesToConnectionFlowControl(streamID protocol.StreamID) (bool, error)
 }

stream_test.go

@@ -93,6 +93,9 @@ func (m *mockFlowControlHandler) RemainingConnectionWindowSize() protocol.ByteCo
 func (m *mockFlowControlHandler) UpdateWindow(streamID protocol.StreamID, offset protocol.ByteCount) (bool, error) {
 	panic("not implemented")
 }
+func (m *mockFlowControlHandler) StreamContributesToConnectionFlowControl(streamID protocol.StreamID) (bool, error) {
+	panic("not implemented")
+}
 
 var _ = Describe("Stream", func() {
 	var (