serve grpc and http on the same socket

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

vendor/github.com/soheilhy/cmux/buffer.go

@@ -0,0 +1,67 @@
+// Copyright 2016 The CMux Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License.
+
+package cmux
+
+import (
+	"bytes"
+	"io"
+)
+
+// bufferedReader is an optimized implementation of io.Reader that behaves like
+// ```
+// io.MultiReader(bytes.NewReader(buffer.Bytes()), io.TeeReader(source, buffer))
+// ```
+// without allocating.
+type bufferedReader struct {
+	source     io.Reader
+	buffer     bytes.Buffer
+	bufferRead int
+	bufferSize int
+	sniffing   bool
+	lastErr    error
+}
+
+func (s *bufferedReader) Read(p []byte) (int, error) {
+	if s.bufferSize > s.bufferRead {
+		// If we have already read something from the buffer before, we return the
+		// same data and the last error if any. We need to immediately return,
+		// otherwise we may block for ever, if we try to be smart and call
+		// source.Read() seeking a little bit of more data.
+		bn := copy(p, s.buffer.Bytes()[s.bufferRead:s.bufferSize])
+		s.bufferRead += bn
+		return bn, s.lastErr
+	} else if !s.sniffing && s.buffer.Cap() != 0 {
+		// We don't need the buffer anymore.
+		// Reset it to release the internal slice.
+		s.buffer = bytes.Buffer{}
+	}
+
+	// If there is nothing more to return in the sniffed buffer, read from the
+	// source.
+	sn, sErr := s.source.Read(p)
+	if sn > 0 && s.sniffing {
+		s.lastErr = sErr
+		if wn, wErr := s.buffer.Write(p[:sn]); wErr != nil {
+			return wn, wErr
+		}
+	}
+	return sn, sErr
+}
+
+func (s *bufferedReader) reset(snif bool) {
+	s.sniffing = snif
+	s.bufferRead = 0
+	s.bufferSize = s.buffer.Len()
+}