From 4e9e4b6cde5d40066d7112add42b5943af4608e5 Mon Sep 17 00:00:00 2001
From: Dreamacro <8615343+Dreamacro@users.noreply.github.com>
Date: Wed, 14 Apr 2021 21:46:05 +0800
Subject: [PATCH] Fix: grpc transport concurrent write

---
 component/gun/gun.go    | 17 +++++++++++++----
 component/gun/leb128.go | 38 --------------------------------------
 2 files changed, 13 insertions(+), 42 deletions(-)
 delete mode 100644 component/gun/leb128.go

diff --git a/component/gun/gun.go b/component/gun/gun.go
index 23383827..f19006ad 100644
--- a/component/gun/gun.go
+++ b/component/gun/gun.go
@@ -5,6 +5,7 @@ package gun
 
 import (
 	"bufio"
+	"bytes"
 	"crypto/tls"
 	"encoding/binary"
 	"errors"
@@ -30,6 +31,7 @@ var (
 		"content-type": []string{"application/grpc"},
 		"user-agent":   []string{"grpc-go/1.36.0"},
 	}
+	bufferPool = sync.Pool{New: func() interface{} { return &bytes.Buffer{} }}
 )
 
 type DialFn = func(network, addr string) (net.Conn, error)
@@ -119,13 +121,20 @@ func (g *Conn) Read(b []byte) (n int, err error) {
 }
 
 func (g *Conn) Write(b []byte) (n int, err error) {
-	protobufHeader := appendUleb128([]byte{0x0A}, uint64(len(b)))
+	protobufHeader := [binary.MaxVarintLen64 + 1]byte{0x0A}
+	varuintSize := binary.PutUvarint(protobufHeader[1:], uint64(len(b)))
 	grpcHeader := make([]byte, 5)
-	grpcPayloadLen := uint32(len(protobufHeader) + len(b))
+	grpcPayloadLen := uint32(varuintSize + 1 + len(b))
 	binary.BigEndian.PutUint32(grpcHeader[1:5], grpcPayloadLen)
 
-	buffers := net.Buffers{grpcHeader, protobufHeader, b}
-	_, err = buffers.WriteTo(g.writer)
+	buf := bufferPool.Get().(*bytes.Buffer)
+	defer bufferPool.Put(buf)
+	defer buf.Reset()
+	buf.Write(grpcHeader)
+	buf.Write(protobufHeader[:varuintSize+1])
+	buf.Write(b)
+
+	_, err = g.writer.Write(buf.Bytes())
 	if err == io.ErrClosedPipe && g.err != nil {
 		err = g.err
 	}
diff --git a/component/gun/leb128.go b/component/gun/leb128.go
deleted file mode 100644
index 5978980d..00000000
--- a/component/gun/leb128.go
+++ /dev/null
@@ -1,38 +0,0 @@
-// Copy from: https://github.com/Equim-chan/leb128
-// License: BSD-3-Clause
-
-package gun
-
-var sevenbits = [...]byte{
-	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
-	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
-	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
-	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
-	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
-	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
-	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
-	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
-}
-
-func appendUleb128(b []byte, v uint64) []byte {
-	// If it's less than or equal to 7-bit
-	if v < 0x80 {
-		return append(b, sevenbits[v])
-	}
-
-	for {
-		c := uint8(v & 0x7f)
-		v >>= 7
-
-		if v != 0 {
-			c |= 0x80
-		}
-
-		b = append(b, c)
-		if c&0x80 == 0 {
-			break
-		}
-	}
-
-	return b
-}