[Bug]: windows下的实现似乎有bug

[Zhanghailin1995]

Actions I've taken before I'm here

• I've thoroughly read the documentations on this issue but still have no clue.
• I've searched the Github Issues but didn't find any duplicate issues that have been resolved.
• I've searched the internet for this issue but didn't find anything helpful.

What happened?

windows下使用gnet2.3.0时似乎有bug，使用gnet.Client.Dial返回一个conn时，直接调用conn.Wake, 会唤起OnTraffic，如果此时在OnTraffic方法中从conn中读取数据，立马就空指针崩溃了，因为此时windows下的实现的conn的buffer为nil，简单的复现代码如下。在linux环境下表现正常。至于为什么要立马调用Wake方法，是因为我在项目中想通过Wake的回调来设置Context，因为conn.Context和GetContext都不是并发安全的

Major version of gnet

v2

Specific version of gnet

v2.3.0

Operating system

Windows

OS version

10 22H2

Go version

go 1.17

Relevant log output

panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x8 pc=0x584942]

goroutine 6 [running]:
github.com/valyala/bytebufferpool.(*ByteBuffer).Len(...)
        C:/Users/*****/go/pkg/mod/github.com/valyala/bytebufferpool@v1.0.0/byte
buffer.go:21
github.com/panjf2000/gnet/v2.(*conn).Peek(0xc00005be50, 0x425fc5)
        C:/Users/*****/go/pkg/mod/github.com/panjf2000/gnet/v2@v2.3.0/connectio
n_windows.go:164 +0x62
main.(*clientEvents).OnTraffic(0x0, {0x61efc0, 0xc0000244e0})
        C:/Workspace/Code/Go/go-sample/gnet_test/examples/client/main.go:19 +0x2
f
github.com/panjf2000/gnet/v2.(*eventloop).wake(0xc000024480, 0xc0000244e0)      
        C:/Users/*****/go/pkg/mod/github.com/panjf2000/gnet/v2@v2.3.0/eventloop
_windows.go:178 +0x5b
github.com/panjf2000/gnet/v2.(*conn).Wake.func2()
        C:/Users/*****/go/pkg/mod/github.com/panjf2000/gnet/v2@v2.3.0/connectio
n_windows.go:437 +0x7b
github.com/panjf2000/gnet/v2.(*eventloop).run(0xc000024480)
        C:/Users/*****/go/pkg/mod/github.com/panjf2000/gnet/v2@v2.3.0/eventloop
_windows.go:79 +0x1f3
golang.org/x/sync/errgroup.(*Group).Go.func1()
        C:/Users/*****/go/pkg/mod/golang.org/x/sync@v0.2.0/errgroup/errgroup.go
:75 +0x64
created by golang.org/x/sync/errgroup.(*Group).Go
        C:/Users/*****/go/pkg/mod/golang.org/x/sync@v0.2.0/errgroup/errgroup.go
:72 +0xa9

Code snippets (optional)

package main

import (
	"github.com/panjf2000/gnet/v2"
	"github.com/panjf2000/gnet/v2/pkg/logging"
	"log"
	"time"
)

type clientEvents struct {
	*gnet.BuiltinEventEngine
}

func (ev *clientEvents) OnBoot(e gnet.Engine) gnet.Action {
	return gnet.None
}

func (ev *clientEvents) OnTraffic(c gnet.Conn) (action gnet.Action) {
	_, err := c.Peek(10)
	if err != nil {
		log.Println(err)
	}
	return gnet.None
}

func main() {

	ev := &clientEvents{}
	client, _ := gnet.NewClient(ev, gnet.WithLogLevel(logging.DebugLevel),
		gnet.WithLockOSThread(true))
	client.Start()

	conn, _ := client.Dial("tcp", ":7399")
	conn.Wake(func(c gnet.Conn, err error) error {
		return nil
	})

	for {
		time.Sleep(time.Second * 10)
	}
}

How to Reproduce

Steps to reproduce the behavior:

1. Go to '....'
2. Click on '....'
3. Do '....'
4. See '....'

Does this issue reproduce with the latest release?

I haven't verified it with the latest release

[panjf2000]

如果只是要设置 context，在 OnOpen 里设置不就行了？

[panjf2000]

正如我前面说所，你的使用应该是有问题，不过考虑到这里确实存在代码在 Windows 和其他操作系统上行为不一致的问题，所以，还是要修复一下。