blob: fcc82ac57f2ce57d5f43f932e7d6ec74520091c4 [file] [log] [blame]
Florian Loitsch310385a2016-02-11 14:53:44 +01001// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
2// for details. All rights reserved. Use of this source code is governed by a
3// BSD-style license that can be found in the LICENSE file.
4
5import "dart:async";
6import "package:expect/expect.dart";
7import "package:async_helper/async_helper.dart";
8
9var events = [];
10
11var timer;
12ticker(period) async* {
13 var sc;
14 sc = new StreamController(onListen: () {
15 events.add("listen");
16 timer = new Timer.periodic(period, (_) {
17 sc.add(null);
18 });
19 }, onCancel: () {
20 events.add("cancel");
21 timer.cancel();
22 });
23
24 try {
25 var counter = 0;
26 await for (var tick in sc.stream) {
27 counter++;
28 }
29 } finally {
30 events.add("finally");
31 }
32}
33
34void main() {
35 asyncStart();
36 events.add("main");
37 final subscription =
38 ticker(const Duration(milliseconds: 20)).listen((val) { });
39
40 bool cancelFinished = false;
41 new Timer(const Duration(milliseconds: 100), () async {
42 // Despite the cancel call below, the stream doesn't stop.
43 // The async* function is not blocked at any await (since the inner timer
44 // continuously ticks), but since there/ is no yield-point in the function
45 // it won't cancel.
46 new Timer(const Duration(milliseconds: 30), () {
47 Expect.isFalse(cancelFinished);
48 Expect.listEquals(["main", "listen", "invoke cancel"], events);
49 timer.cancel();
50 asyncEnd();
51 });
52
53 events.add("invoke cancel");
54 await subscription.cancel();
55 // This line should never be reached, since the cancel-future doesn't
56 // complete.
57 cancelFinished = true;
58 });
59}