avoid allocation from timeout queue iterator (#710)

Author: paulwe

utils/event_emitter.go

@@ -75,7 +75,11 @@ func (e *EventEmitter[K, V]) Observe(k K) *EventObserver[V] {
 	o := l.Observe()
 	e.mu.Unlock()
 
-	o.stop = append(o.stop, func() { e.cleanUpObserverList(k) })
+	stop := o.stop
+	o.stop = func() {
+		stop()
+		e.cleanUpObserverList(k)
+	}
 
 	return o
 }
@@ -129,7 +133,7 @@ func (l *EventObserverList[V]) Observe() *EventObserver[V] {
 	le := l.observers.PushBack(o)
 	l.mu.Unlock()
 
-	o.stop = append(o.stop, func() { l.stopObserving(le) })
+	o.stop = func() { l.stopObserving(le) }
 
 	return o
 }
@@ -150,14 +154,14 @@ func (l *EventObserverList[V]) stopObserving(le *list.Element) {
 
 type EventObserver[V any] struct {
 	logger logger.Logger
-	stop   []func()
+	stop   func()
 	ch     chan V
 }
 
 func NewEventObserver[V any](stopFunc func()) (*EventObserver[V], func(v V)) {
 	o := &EventObserver[V]{
 		logger: logger.GetLogger(),
-		stop:   []func(){stopFunc},
+		stop:   stopFunc,
 		ch:     make(chan V, defaultQueueSize),
 	}
 	return o, o.emit
@@ -172,9 +176,7 @@ func (o *EventObserver[V]) emit(v V) {
 }
 
 func (o *EventObserver[V]) Stop() {
-	for _, stop := range o.stop {
-		stop()
-	}
+	o.stop()
 }
 
 func (o *EventObserver[V]) Events() <-chan V {

utils/event_emitter_test.go

@@ -43,9 +43,11 @@ func TestEventEmitter(t *testing.T) {
 		default:
 		}
 
+		ao0.Stop()
+
 		keys := emitter.ObservedKeys()
 		sort.Strings(keys)
-		require.Equal(t, []string{"a", "b"}, keys)
+		require.Equal(t, []string{"b"}, keys)
 	})
 
 	t.Run("observer", func(t *testing.T) {

utils/timeoutqueue.go

@@ -100,11 +100,11 @@ func (q *TimeoutQueue[T]) remove(i *TimeoutQueueItem[T]) {
 	i.prev = nil
 }
 
-func (q *TimeoutQueue[T]) IterateAfter(timeout time.Duration) *timeoutQueueIterator[T] {
+func (q *TimeoutQueue[T]) IterateAfter(timeout time.Duration) timeoutQueueIterator[T] {
 	return newTimeoutQueueIterator(q, timeout, false)
 }
 
-func (q *TimeoutQueue[T]) IterateRemoveAfter(timeout time.Duration) *timeoutQueueIterator[T] {
+func (q *TimeoutQueue[T]) IterateRemoveAfter(timeout time.Duration) timeoutQueueIterator[T] {
 	return newTimeoutQueueIterator(q, timeout, true)
 }
 
@@ -115,8 +115,8 @@ type timeoutQueueIterator[T any] struct {
 	item   *TimeoutQueueItem[T]
 }
 
-func newTimeoutQueueIterator[T any](q *TimeoutQueue[T], timeout time.Duration, remove bool) *timeoutQueueIterator[T] {
-	return &timeoutQueueIterator[T]{
+func newTimeoutQueueIterator[T any](q *TimeoutQueue[T], timeout time.Duration, remove bool) timeoutQueueIterator[T] {
+	return timeoutQueueIterator[T]{
 		q:      q,
 		time:   time.Now().Add(-timeout),
 		remove: remove,