First commit

repeat_timer.go

@@ -0,0 +1,72 @@
+package common
+
+import "time"
+import "sync"
+
+/*
+RepeatTimer repeatedly sends a struct{}{} to .Ch after each "dur" period.
+It's good for keeping connections alive.
+A RepeatTimer must be Stop()'d or it will keep a goroutine alive.
+*/
+type RepeatTimer struct {
+	Ch chan time.Time
+
+	mtx    sync.Mutex
+	name   string
+	ticker *time.Ticker
+	quit   chan struct{}
+	dur    time.Duration
+}
+
+func NewRepeatTimer(name string, dur time.Duration) *RepeatTimer {
+	var t = &RepeatTimer{
+		Ch:     make(chan time.Time),
+		ticker: time.NewTicker(dur),
+		quit:   make(chan struct{}),
+		name:   name,
+		dur:    dur,
+	}
+	go t.fireRoutine(t.ticker)
+	return t
+}
+
+func (t *RepeatTimer) fireRoutine(ticker *time.Ticker) {
+	for {
+		select {
+		case t_ := <-ticker.C:
+			t.Ch <- t_
+		case <-t.quit:
+			return
+		}
+	}
+}
+
+// Wait the duration again before firing.
+func (t *RepeatTimer) Reset() {
+	t.Stop()
+
+	t.mtx.Lock() // Lock
+	defer t.mtx.Unlock()
+
+	t.ticker = time.NewTicker(t.dur)
+	t.quit = make(chan struct{})
+	go t.fireRoutine(t.ticker)
+}
+
+// For ease of .Stop()'ing services before .Start()'ing them,
+// we ignore .Stop()'s on nil RepeatTimers.
+func (t *RepeatTimer) Stop() bool {
+	if t == nil {
+		return false
+	}
+	t.mtx.Lock() // Lock
+	defer t.mtx.Unlock()
+
+	exists := t.ticker != nil
+	if exists {
+		t.ticker.Stop()
+		t.ticker = nil
+		close(t.quit)
+	}
+	return exists
+}