From 351de5ee6a60d24a60539317697aa2eefa98bbba Mon Sep 17 00:00:00 2001
From: john <john@johng.cn>
Date: Sun, 17 May 2020 12:46:28 +0800
Subject: [PATCH] fix concurrent issue in buffer handling of package grand

---
 .example/other/test2.go    | 44 ++++----------------------------------
 util/grand/grand_buffer.go |  4 +++-
 2 files changed, 7 insertions(+), 41 deletions(-)

diff --git a/.example/other/test2.go b/.example/other/test2.go
index 616e55134..ff431bbfa 100644
--- a/.example/other/test2.go
+++ b/.example/other/test2.go
@@ -2,47 +2,11 @@ package main
 
 import (
 	"fmt"
-	"net"
 )
 
-func getMacAddrs() (macAddrs []string) {
-	netInterfaces, err := net.Interfaces()
-	if err != nil {
-		fmt.Printf("fail to get net interfaces: %v", err)
-		return macAddrs
-	}
-
-	for _, netInterface := range netInterfaces {
-		macAddr := netInterface.HardwareAddr.String()
-		if len(macAddr) == 0 {
-			continue
-		}
-
-		macAddrs = append(macAddrs, macAddr)
-	}
-	return macAddrs
-}
-
-func getIPs() (ips []string) {
-
-	interfaceAddr, err := net.InterfaceAddrs()
-	if err != nil {
-		fmt.Printf("fail to get net interface addrs: %v", err)
-		return ips
-	}
-
-	for _, address := range interfaceAddr {
-		ipNet, isValidIpNet := address.(*net.IPNet)
-		if isValidIpNet && !ipNet.IP.IsLoopback() {
-			if ipNet.IP.To4() != nil {
-				ips = append(ips, ipNet.IP.String())
-			}
-		}
-	}
-	return ips
-}
-
 func main() {
-	fmt.Printf("mac addrs: %q\n", getMacAddrs())
-	fmt.Printf("ips: %q\n", getIPs())
+	b1 := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 0}
+	b2 := b1[:2]
+	b1[0] = 9
+	fmt.Println(b2)
 }
diff --git a/util/grand/grand_buffer.go b/util/grand/grand_buffer.go
index ab6bd391c..95c658444 100644
--- a/util/grand/grand_buffer.go
+++ b/util/grand/grand_buffer.go
@@ -35,7 +35,9 @@ func asyncProducingRandomBufferBytesLoop() {
 			panic(err)
 		} else {
 			for i := 0; i < n-4; i += 4 {
-				bufferChan <- buffer[i : i+4]
+				b := make([]byte, 4)
+				copy(b, buffer[i:i+4])
+				bufferChan <- b
 			}
 		}
 	}