add wait timeout function

fn.go

@@ -0,0 +1,55 @@
+package stario
+
+import (
+	"errors"
+	"time"
+)
+
+var ERR_TIMEOUT = errors.New("TIME OUT")
+
+func StopUntilTimeout(tm time.Duration, fn func(chan struct{}) error) error {
+	var err error
+	finished := make(chan struct{})
+	imout := make(chan struct{})
+	go func() {
+		err = fn(imout)
+		finished <- struct{}{}
+	}()
+	select {
+	case <-finished:
+		return err
+	case <-time.After(tm):
+		close(imout)
+		return ERR_TIMEOUT
+	}
+}
+
+func StopUntilFinished(fn func() error) <-chan error {
+	finished := make(chan error)
+	go func() {
+		err := fn()
+		finished <- err
+	}()
+	return finished
+}
+
+func StopUntilTimeoutFinished(tm time.Duration, fn func(chan struct{}) error) <-chan error {
+	var err error
+	finished := make(chan struct{})
+	result := make(chan error)
+	imout := make(chan struct{})
+	go func() {
+		err = fn(imout)
+		finished <- struct{}{}
+	}()
+	go func() {
+		select {
+		case <-finished:
+			result <- err
+		case <-time.After(tm):
+			close(imout)
+			result <- ERR_TIMEOUT
+		}
+	}()
+	return result
+}