simplify the stream by directly popping STREAM frames from it

crypto_stream.go

@@ -12,10 +12,9 @@ type cryptoStreamI interface {
 	io.Reader
 	io.Writer
 	AddStreamFrame(*wire.StreamFrame) error
-	HasDataForWriting() bool
-	GetDataForWriting(maxBytes protocol.ByteCount) (data []byte, shouldSendFin bool)
-	GetWriteOffset() protocol.ByteCount
+	PopStreamFrame(protocol.ByteCount) *wire.StreamFrame
 	Cancel(error)
+	HasDataForWriting() bool
 	SetReadOffset(protocol.ByteCount)
 	// methods needed for flow control
 	GetWindowUpdate() protocol.ByteCount
@@ -27,6 +26,8 @@ type cryptoStream struct {
 	*stream
 }
 
+var _ cryptoStreamI = &cryptoStream{}
+
 func newCryptoStream(onData func(), flowController flowcontrol.StreamFlowController, version protocol.VersionNumber) cryptoStreamI {
 	str := newStream(version.CryptoStreamID(), onData, nil, flowController, version)
 	return &cryptoStream{str}
@@ -39,3 +40,10 @@ func (s *cryptoStream) SetReadOffset(offset protocol.ByteCount) {
 	s.readOffset = offset
 	s.frameQueue.readPosition = offset
 }
+
+func (s *cryptoStream) HasDataForWriting() bool {
+	s.mutex.Lock()
+	hasData := s.dataForWriting != nil
+	s.mutex.Unlock()
+	return hasData
+}