change WaitTimeout to WaitWithContext

Author: hslam

watcher.go

@@ -4,10 +4,10 @@
 package rpc
 
 import (
+	"context"
 	"errors"
 	"sync"
 	"sync/atomic"
-	"time"
 )
 
 // ErrWatcherShutdown is returned when the watcher is shut down.
@@ -35,8 +35,8 @@ func freeEvent(e *event) {
 type Watcher interface {
 	// Wait will return value when the key is triggered.
 	Wait() ([]byte, error)
-	// WaitTimeout acts like Wait but takes a timeout.
-	WaitTimeout(time.Duration) ([]byte, error)
+	// WaitWithContext acts like Wait but takes a context.
+	WaitWithContext(context.Context) ([]byte, error)
 	// Stop stops the watch.
 	Stop() error
 }
@@ -89,22 +89,16 @@ func (w *watcher) Wait() (value []byte, err error) {
 	return
 }
 
-func (w *watcher) WaitTimeout(timeout time.Duration) (value []byte, err error) {
-	if timeout <= 0 {
-		return w.Wait()
-	}
-	timer := time.NewTimer(timeout)
+func (w *watcher) WaitWithContext(ctx context.Context) (value []byte, err error) {
 	select {
 	case e := <-w.C:
-		timer.Stop()
 		w.triggerNext()
 		value = e.Value
 		err = e.Error
 		freeEvent(e)
-	case <-timer.C:
-		err = ErrTimeout
+	case <-ctx.Done():
+		err = ctx.Err()
 	case <-w.done:
-		timer.Stop()
 		err = ErrWatcherShutdown
 	}
 	return

watcher_test.go

@@ -4,6 +4,7 @@
 package rpc
 
 import (
+	"context"
 	"testing"
 	"time"
 )
@@ -16,7 +17,7 @@ func TestWatcherTrigger(t *testing.T) {
 		watcher.trigger(e)
 	}
 	for i := byte(0); i < 255; i++ {
-		v, err := watcher.WaitTimeout(0)
+		v, err := watcher.Wait()
 		if err != nil {
 			t.Error(err)
 		} else if len(v) == 0 {
@@ -42,29 +43,44 @@ func TestWatcherTriggerTimeout(t *testing.T) {
 		watcher.trigger(e)
 	}
 	for i := byte(0); i < 255; i++ {
-		v, err := watcher.WaitTimeout(time.Minute)
+		ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+		v, err := watcher.WaitWithContext(ctx)
 		if err != nil {
 			t.Error(err)
 		} else if len(v) == 0 {
 			t.Error("len == 0")
 		} else if v[0] != i {
 			t.Error("out of order")
 		}
+		cancel()
 	}
 	go func() {
-		close(watcher.done)
+		watcher.stop()
 	}()
-	_, err := watcher.WaitTimeout(time.Minute)
+	_, err := watcher.Wait()
 	if err != ErrWatcherShutdown {
 		t.Error(err)
 	}
 }
 
 func TestWatcherTriggerTimeoutErr(t *testing.T) {
 	watcher := &watcher{C: make(chan *event, 10), done: make(chan struct{}, 1)}
-	_, err := watcher.WaitTimeout(time.Millisecond * 1)
-	if err != ErrTimeout {
-		t.Error(err)
+	{
+		ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*1)
+		_, err := watcher.WaitWithContext(ctx)
+		if err == nil {
+			t.Error()
+		}
+		cancel()
 	}
-	close(watcher.done)
+	watcher.stop()
+	{
+		ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*1)
+		_, err := watcher.WaitWithContext(ctx)
+		if err != ErrWatcherShutdown {
+			t.Error(err)
+		}
+		cancel()
+	}
+
 }