Golang通道的无阻塞读写的方法示例

// 场景1
func ReadNoDataFromNoBufCh() {
 noBufCh := make(chan int)

 <-noBufCh
 fmt.Println("read from no buffer channel success")

 // Output:
 // fatal error: all goroutines are asleep - deadlock!
}

// 场景2
func WriteNoBufCh() {
 ch := make(chan int)

 ch <- 1
 fmt.Println("write success no block")
 
 // Output:
 // fatal error: all goroutines are asleep - deadlock!
}

// 场景1
func ReadNoDataFromBufCh() {
 bufCh := make(chan int, 1)

 <-bufCh
 fmt.Println("read from no buffer channel success")

 // Output:
 // fatal error: all goroutines are asleep - deadlock!
}

// 场景2
func WriteBufChButFull() {
 ch := make(chan int, 1)
 // make ch full
 ch <- 100

 ch <- 1
 fmt.Println("write success no block")
 
 // Output:
 // fatal error: all goroutines are asleep - deadlock!
}

// 无缓冲通道读
func ReadNoDataFromNoBufChWithSelect() {
 bufCh := make(chan int)

 if v, err := ReadWithSelect(bufCh); err != nil {
  fmt.Println(err)
 } else {
  fmt.Printf("read: %d\n", v)
 }

 // Output:
 // channel has no data
}

// 有缓冲通道读
func ReadNoDataFromBufChWithSelect() {
 bufCh := make(chan int, 1)

 if v, err := ReadWithSelect(bufCh); err != nil {
  fmt.Println(err)
 } else {
  fmt.Printf("read: %d\n", v)
 }

 // Output:
 // channel has no data
}

// select结构实现通道读
func ReadWithSelect(ch chan int) (x int, err error) {
 select {
 case x = <-ch:
  return x, nil
 default:
  return 0, errors.New("channel has no data")
 }
}

// 无缓冲通道写
func WriteNoBufChWithSelect() {
 ch := make(chan int)
 if err := WriteChWithSelect(ch); err != nil {
  fmt.Println(err)
 } else {
  fmt.Println("write success")
 }

 // Output:
 // channel blocked, can not write
}

// 有缓冲通道写
func WriteBufChButFullWithSelect() {
 ch := make(chan int, 1)
 // make ch full
 ch <- 100
 if err := WriteChWithSelect(ch); err != nil {
  fmt.Println(err)
 } else {
  fmt.Println("write success")
 }

 // Output:
 // channel blocked, can not write
}

// select结构实现通道写
func WriteChWithSelect(ch chan int) error {
 select {
 case ch <- 1:
  return nil
 default:
  return errors.New("channel blocked, can not write")
 }
}

func ReadWithSelect(ch chan int) (x int, err error) {
 timeout := time.NewTimer(time.Microsecond * 500)

 select {
 case x = <-ch:
  return x, nil
 case <-timeout.C:
  return 0, errors.New("read time out")
 }
}

func WriteChWithSelect(ch chan int) error {
 timeout := time.NewTimer(time.Microsecond * 500)

 select {
 case ch <- 1:
  return nil
 case <-timeout.C:
  return errors.New("write time out")
 }
}