我有以下go代码来等待流。预期的输出是:
line1
line2
line3
line4
line5
escape1
scan done
done....
但在line5
之后,我的代码一直悬而未决。
var lines = `
line1
line2
line3
line4
line5
line6
line7
`
func main() {
var (
donec = make(chan struct{})
stream = make(chan string, 5000)
exitc = make(chan struct{})
)
go func() {
scanner := bufio.NewScanner(strings.NewReader(lines))
escape1:
for {
for scanner.Scan() {
select {
case <-donec:
fmt.Println("escape1")
close(stream)
break escape1
default:
stream <- scanner.Text()
}
}
}
close(exitc)
fmt.Println("scan done")
return
}()
escape2:
for {
select {
case txt, ok := <-stream:
if !ok {
fmt.Println("stream closed!")
}
fmt.Println(txt)
if strings.Contains(txt, "line5") {
close(donec)
<-exitc
break escape2
}
}
}
fmt.Println("done....")
}
认为我做的一切都是正确的。有人可以帮我调试这个挂码吗?
谢谢!
答案 0 :(得分:1)
我认为这是因为你的escape1
for循环包裹了for scanner.Scan()
循环。
当我删除外部for循环时,它对我来说很好:https://play.golang.org/p/NU3m3Deil7
func main() {
var (
donec = make(chan struct{})
stream = make(chan string, 5000)
exitc = make(chan struct{})
)
go func() {
scanner := bufio.NewScanner(strings.NewReader(lines))
escape1:
for scanner.Scan() {
select {
case <-donec:
fmt.Println("escape1")
close(stream)
break escape1
default:
stream <- scanner.Text()
}
}
close(exitc)
fmt.Println("scan done")
return
}()
escape2:
for {
select {
case txt, ok := <-stream:
if !ok {
fmt.Println("stream closed!")
}
fmt.Println(txt)
if strings.Contains(txt, "line5") {
close(donec)
<-exitc
break escape2
}
}
}
fmt.Println("done....")
}