From 0ad629ca31c3cb9a783d7611bf799534e6af32d5 Mon Sep 17 00:00:00 2001
From: Darien Raymond <admin@v2ray.com>
Date: Thu, 8 Dec 2016 11:21:24 +0100
Subject: [PATCH] remove use of prepend

---
 app/dispatcher/testing/dispatcher.go |  8 ++++++--
 proxy/shadowsocks/ota.go             | 10 +++++++---
 proxy/shadowsocks/ota_test.go        |  3 ---
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/app/dispatcher/testing/dispatcher.go b/app/dispatcher/testing/dispatcher.go
index 4f853c3d3..92fd3ef5c 100644
--- a/app/dispatcher/testing/dispatcher.go
+++ b/app/dispatcher/testing/dispatcher.go
@@ -1,6 +1,7 @@
 package testing
 
 import (
+	"v2ray.com/core/common/alloc"
 	v2net "v2ray.com/core/common/net"
 	"v2ray.com/core/proxy"
 	"v2ray.com/core/transport/ray"
@@ -19,8 +20,11 @@ func NewTestPacketDispatcher(handler func(destination v2net.Destination, traffic
 				if err != nil {
 					break
 				}
-				payload.Prepend([]byte("Processed: "))
-				traffic.OutboundOutput().Write(payload)
+				output := alloc.NewBuffer()
+				output.Append([]byte("Processed: "))
+				output.Append(payload.Bytes())
+				payload.Release()
+				traffic.OutboundOutput().Write(output)
 			}
 			traffic.OutboundOutput().Close()
 		}
diff --git a/proxy/shadowsocks/ota.go b/proxy/shadowsocks/ota.go
index e3b2e6cbe..b8e799cbc 100644
--- a/proxy/shadowsocks/ota.go
+++ b/proxy/shadowsocks/ota.go
@@ -5,6 +5,7 @@ import (
 	"crypto/hmac"
 	"crypto/sha1"
 	"io"
+
 	"v2ray.com/core/common/alloc"
 	"v2ray.com/core/common/errors"
 	"v2ray.com/core/common/serial"
@@ -111,12 +112,14 @@ func (v *ChunkReader) Read() (*alloc.Buffer, error) {
 type ChunkWriter struct {
 	writer io.Writer
 	auth   *Authenticator
+	buffer []byte
 }
 
 func NewChunkWriter(writer io.Writer, auth *Authenticator) *ChunkWriter {
 	return &ChunkWriter{
 		writer: writer,
 		auth:   auth,
+		buffer: make([]byte, 32*1024),
 	}
 }
 
@@ -127,8 +130,9 @@ func (v *ChunkWriter) Release() {
 
 func (v *ChunkWriter) Write(payload *alloc.Buffer) error {
 	totalLength := payload.Len()
-	payload.PrependFunc(AuthSize, v.auth.Authenticate(payload.Bytes()))
-	payload.PrependFunc(2, serial.WriteUint16(uint16(totalLength)))
-	_, err := v.writer.Write(payload.Bytes())
+	serial.Uint16ToBytes(uint16(totalLength), v.buffer[:0])
+	v.auth.Authenticate(payload.Bytes())(v.buffer[2:])
+	copy(v.buffer[2+AuthSize:], payload.Bytes())
+	_, err := v.writer.Write(v.buffer[:2+AuthSize+payload.Len()])
 	return err
 }
diff --git a/proxy/shadowsocks/ota_test.go b/proxy/shadowsocks/ota_test.go
index e5d001574..d436082d2 100644
--- a/proxy/shadowsocks/ota_test.go
+++ b/proxy/shadowsocks/ota_test.go
@@ -19,9 +19,6 @@ func TestNormalChunkReading(t *testing.T) {
 	payload, err := reader.Read()
 	assert.Error(err).IsNil()
 	assert.Bytes(payload.Bytes()).Equals([]byte{11, 12, 13, 14, 15, 16, 17, 18})
-
-	payload.PrependBytes(3, 4)
-	assert.Bytes(payload.Bytes()).Equals([]byte{3, 4, 11, 12, 13, 14, 15, 16, 17, 18})
 }
 
 func TestNormalChunkWriting(t *testing.T) {