From c877497cc96d7d71fd622e1d29e50a793ce69d8e Mon Sep 17 00:00:00 2001
From: fooofei <aihujianfei@qq.com>
Date: Sun, 4 Oct 2020 10:37:36 +0800
Subject: [PATCH] user io.ReadFull for shorter connection read code

---
 src/comm/comm.go | 41 +++++++++++++----------------------------
 1 file changed, 13 insertions(+), 28 deletions(-)

diff --git a/src/comm/comm.go b/src/comm/comm.go
index f3732c65..d2c1b9c2 100644
--- a/src/comm/comm.go
+++ b/src/comm/comm.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
+	"io"
 	"net"
 	"time"
 
@@ -85,22 +86,15 @@ func (c *Comm) Read() (buf []byte, numBytes int, bs []byte, err error) {
 	if err := c.connection.SetReadDeadline(time.Now().Add(3 * time.Hour)); err != nil {
 		log.Warnf("error setting read deadline: %v", err)
 	}
+	// must clear the timeout setting
+	defer c.connection.SetDeadline(time.Time{})
 
 	// read until we get 4 bytes for the header
-	var header []byte
-	numBytes = 4
-	for {
-		tmp := make([]byte, numBytes-len(header))
-		n, errRead := c.connection.Read(tmp)
-		if errRead != nil {
-			err = errRead
-			log.Debugf("initial read error: %v", err)
-			return
-		}
-		header = append(header, tmp[:n]...)
-		if numBytes == len(header) {
-			break
-		}
+	header := make([]byte, 4)
+	_, err = io.ReadFull(c.connection, header)
+	if err != nil {
+		log.Debugf("initial read error: %v", err)
+		return
 	}
 
 	var numBytesUint32 uint32
@@ -117,25 +111,16 @@ func (c *Comm) Read() (buf []byte, numBytes int, bs []byte, err error) {
 		log.Debug(err)
 		return
 	}
-	buf = make([]byte, 0)
 
 	// shorten the reading deadline in case getting weird data
 	if err := c.connection.SetReadDeadline(time.Now().Add(10 * time.Second)); err != nil {
 		log.Warnf("error setting read deadline: %v", err)
 	}
-	for {
-		// log.Debugf("bytes: %d/%d", len(buf), numBytes)
-		tmp := make([]byte, numBytes-len(buf))
-		n, errRead := c.connection.Read(tmp)
-		if errRead != nil {
-			err = errRead
-			log.Debugf("consecutive read error: %v", err)
-			return
-		}
-		buf = append(buf, tmp[:n]...)
-		if numBytes == len(buf) {
-			break
-		}
+	buf = make([]byte, numBytes)
+	_, err = io.ReadFull(c.connection, buf)
+	if err != nil {
+		log.Debugf("consecutive read error: %v", err)
+		return
 	}
 	return
 }