golang write_unix_test 代码
文件路径：/src/net/write_unix_test.go
/ Copyright 2017 The Go Authors. All rights reserved.
/ Use of this source code is governed by a BSD-style
/ license that can be found in the LICENSE file.
/go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
package net
import (
"bytes"
"syscall"
"testing"
"time"
)
/ Test that a client can't trigger an endless loop of write system
/ calls on the server by shutting down the write side on the client.
/ Possibility raised in the discussion of https://golang.org/cl/71973.
func TestEndlessWrite(t *testing.T) {
t.Parallel()
c := make(chan bool)
server := func(cs *TCPConn) error {
cs.CloseWrite()
<-c
return nil
}
client := func(ss *TCPConn) error {
/ Tell the server to return when we return.
defer close(c)
/ Loop writing to the server. The server is not reading
/ anything, so this will eventually block, and then time out.
b := bytes.Repeat([]byte{'a'}, 8192)
cagain := 0
for {
n, err := ss.conn.fd.pfd.WriteOnce(b)
if n > 0 {
cagain = 0
}
switch err {
case nil:
case syscall.EAGAIN:
if cagain == 0 {
/ We've written enough data to
/ start blocking. Set a deadline
/ so that we will stop.
ss.SetWriteDeadline(time.Now().Add(5 * time.Millisecond))
}
cagain++
if cagain > 20 {
t.Error("looping on EAGAIN")
return nil
}
if err = ss.conn.fd.pfd.WaitWrite(); err != nil {
t.Logf("client WaitWrite: %v", err)
return nil
}
default:
/ We expect to eventually get an error.
t.Logf("client WriteOnce: %v", err)
return nil
}
}
}
withTCPConnPair(t, client, server)
}