ordone-channel.go

package main

import (
	"fmt"
	"time"
)

func main() {
	doneOrDone := make(chan interface{})
	doneRepeat := make(chan interface{})
	doneMain := make(chan interface{})

	go func() {
		time.Sleep(time.Second * 2)
		close(doneOrDone)
	}()

	repeat := func(done <-chan interface{}, values ...interface{}) <-chan interface{} {
		valueStream := make(chan interface{})
		go func() {
			defer func() {
				close(valueStream)
				fmt.Println("closed")
			}()
			for {
				time.Sleep(time.Millisecond * 100)
				for _, v := range values {
					select {
					case <-done:
						return
					case valueStream <- v:
					}
				}
			}
		}()
		return valueStream
	}

	orDone := func(done <-chan interface{}, c <-chan interface{}) <-chan interface{} {
		valStream := make(chan interface{})
		go func() {
			defer func() {
				close(valStream)
				close(doneMain)
			}()
			for {
				select {
				case <-done:
					fmt.Println("done. first")
					return
				case v, ok := <-c:
					if ok == false {
						fmt.Println("channel closed")
						return
					}
					select {
					case valStream <- v:
						fmt.Println("valStream")
					case <-done:
						fmt.Println("done. second")
					}
				}
			}
		}()
		return valStream
	}

	generater := repeat(doneRepeat, []interface{}{1, 2, 3, 4, 5})

	var i int
	for v := range orDone(done, generater) {

		i++
		if i > 2 {
			break
		}
		fmt.Printf("i: %d, value: %v\n", i, v)
	}
	<-doneMain
	fmt.Println("Done")
}