Robert Nystrom
fc1b1ecc71
Change-Id: Idbcc965a27e9ffeedf5e0a1068b019de4193070f Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/127745 Commit-Queue: Bob Nystrom <rnystrom@google.com> Reviewed-by: Alexander Thomas <athom@google.com>
60 lines
1.6 KiB
Dart
60 lines
1.6 KiB
Dart
// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import "dart:async";
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import "package:expect/expect.dart";
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import "package:async_helper/async_helper.dart";
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var events = [];
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var timer;
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ticker(period) async* {
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var sc;
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sc = new StreamController(onListen: () {
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events.add("listen");
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timer = new Timer.periodic(period, (_) {
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sc.add(null);
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});
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}, onCancel: () {
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events.add("cancel");
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timer.cancel();
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});
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try {
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var counter = 0;
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await for (var tick in sc.stream) {
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counter++;
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}
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} finally {
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events.add("finally");
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}
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}
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void main() {
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asyncStart();
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events.add("main");
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final subscription =
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ticker(const Duration(milliseconds: 20)).listen((val) {});
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bool cancelFinished = false;
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new Timer(const Duration(milliseconds: 100), () async {
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// Despite the cancel call below, the stream doesn't stop.
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// The async* function is not blocked at any await (since the inner timer
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// continuously ticks), but since there/ is no yield-point in the function
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// it won't cancel.
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new Timer(const Duration(milliseconds: 30), () {
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Expect.isFalse(cancelFinished);
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Expect.listEquals(["main", "listen", "invoke cancel"], events);
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timer.cancel();
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asyncEnd();
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});
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events.add("invoke cancel");
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await subscription.cancel();
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// This line should never be reached, since the cancel-future doesn't
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// complete.
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cancelFinished = true;
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});
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}
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