From aab1461e0d9c4ccb49cc3b8aa85a7f56c4fb8169 Mon Sep 17 00:00:00 2001
From: deadprogram <ron@hybridgroup.com>
Date: Fri, 13 May 2016 17:21:21 -0700
Subject: [PATCH] [core] gobot.Every function now returns a channel so it can
 be halted

Signed-off-by: deadprogram <ron@hybridgroup.com>
---
 utils.go      | 20 +++++++++++++++-----
 utils_test.go | 12 ++++++++++++
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/utils.go b/utils.go
index aa6b0bd4..48f2c4a1 100644
--- a/utils.go
+++ b/utils.go
@@ -23,17 +23,27 @@ var eventError = func(e *Event) (err error) {
 	return
 }
 
-// Every triggers f every t time until the end of days. It does not wait for the
-// previous execution of f to finish before it fires the next f.
-func Every(t time.Duration, f func()) {
+// Every triggers f every t time until the end of days, or when a
+// bool value is sent to the channel returned by the Every function.
+// It does not wait for the previous execution of f to finish before
+// it fires the next f.
+func Every(t time.Duration, f func()) chan bool {
+	done := make(chan bool)
 	c := time.Tick(t)
 
 	go func() {
 		for {
-			<-c
-			go f()
+			select {
+			case <-done:
+				break
+			default:
+				<-c
+				go f()
+			}
 		}
 	}()
+
+	return done
 }
 
 // After triggers f after t duration.
diff --git a/utils_test.go b/utils_test.go
index 7d702e1d..212fe500 100644
--- a/utils_test.go
+++ b/utils_test.go
@@ -24,6 +24,18 @@ func TestEvery(t *testing.T) {
 	}
 }
 
+func TestEveryWhenDone(t *testing.T) {
+	i := 0
+	done := Every(20*time.Millisecond, func() {
+		i++
+	})
+	<-time.After(20 * time.Millisecond)
+	done <- true
+	if i > 1 {
+		t.Error("Test should have stopped after 20ms")
+	}
+}
+
 func TestAfter(t *testing.T) {
 	i := 0
 	After(1*time.Millisecond, func() {