tcopy.go

package main

import (
	"fmt"
	"io"
	"os"
	"time"
)

func main() {
	tcopy(os.Stdout, os.Stdin, 1*time.Second)
}

func tcopy(wr io.Writer, rd io.Reader, tout time.Duration) {
	rdsig := make(chan int)
	buf := make([]byte, 1024)

F:
	for {
		go func() {
			n, err := rd.Read(buf)
			if err != nil {
				fmt.Println("read error", err)
				close(rdsig)
			} else {
				rdsig <- n
			}
		}()
		select {
		case <-time.After(tout):
			fmt.Println("read timeout, exiting")
			break F
		case _, ok := <-rdsig:
			if !ok {
				break F
			}
		}
		wr.Write(buf)
	}
}