| // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| import "dart:async"; |
| import "package:expect/expect.dart"; |
| import "package:async_helper/async_helper.dart"; |
| |
| class Trace { |
| String trace = ""; |
| record(x) { |
| trace += x.toString(); |
| } |
| |
| toString() => trace; |
| } |
| |
| Stream makeMeAStream() { |
| return timedCounter(5); |
| } |
| |
| Trace t1 = new Trace(); |
| |
| Future consumeOne() async { |
| // Equivalent to await for (x in makeMeAStream()) { ... } |
| var s = makeMeAStream(); |
| var it = new StreamIterator(s); |
| while (await it.moveNext()) { |
| var x = it.current; |
| t1.record(x); |
| } |
| t1.record("X"); |
| } |
| |
| Trace t2 = new Trace(); |
| |
| Future consumeTwo() async { |
| await for (var x in makeMeAStream()) { |
| t2.record(x); |
| } |
| t2.record("Y"); |
| } |
| |
| Trace t3 = new Trace(); |
| |
| Future consumeNested() async { |
| await for (var x in makeMeAStream()) { |
| t3.record(x); |
| await for (var y in makeMeAStream()) { |
| t3.record(y); |
| } |
| t3.record("|"); |
| } |
| t3.record("Z"); |
| } |
| |
| Trace t4 = new Trace(); |
| |
| Future consumeSomeOfInfinite() async { |
| int i = 0; |
| await for (var x in infiniteStream()) { |
| i++; |
| if (i > 10) break; |
| t4.record(x); |
| } |
| t4.record("U"); |
| } |
| |
| main() { |
| var f1 = consumeOne(); |
| t1.record("T1:"); |
| |
| var f2 = consumeTwo(); |
| t2.record("T2:"); |
| |
| var f3 = consumeNested(); |
| t3.record("T3:"); |
| |
| var f4 = consumeSomeOfInfinite(); |
| t4.record("T4:"); |
| |
| asyncStart(); |
| Future.wait([f1, f2, f3, f4]).then((_) { |
| Expect.equals("T1:12345X", t1.toString()); |
| Expect.equals("T2:12345Y", t2.toString()); |
| Expect.equals("T3:112345|212345|312345|412345|512345|Z", t3.toString()); |
| Expect.equals("T4:12345678910U", t4.toString()); |
| asyncEnd(); |
| }); |
| } |
| |
| // Create a stream that produces numbers [1, 2, ... maxCount] |
| Stream timedCounter(int maxCount) { |
| late StreamController controller; |
| Timer? timer; |
| int counter = 0; |
| |
| void tick(_) { |
| counter++; |
| controller.add(counter); // Ask stream to send counter values as event. |
| if (counter >= maxCount) { |
| timer!.cancel(); |
| controller.close(); // Ask stream to shut down and tell listeners. |
| } |
| } |
| |
| void startTimer() { |
| timer = new Timer.periodic(const Duration(milliseconds: 10), tick); |
| } |
| |
| void stopTimer() { |
| timer?.cancel(); |
| timer = null; |
| } |
| |
| controller = new StreamController( |
| onListen: startTimer, |
| onPause: stopTimer, |
| onResume: startTimer, |
| onCancel: stopTimer); |
| |
| return controller.stream; |
| } |
| |
| // Create a stream that produces numbers [1, 2, ... ] |
| Stream infiniteStream() { |
| late StreamController controller; |
| Timer? timer; |
| int counter = 0; |
| |
| void tick(_) { |
| counter++; |
| controller.add(counter); // Ask stream to send counter values as event. |
| } |
| |
| void startTimer() { |
| timer = new Timer.periodic(const Duration(milliseconds: 10), tick); |
| } |
| |
| void stopTimer() { |
| timer?.cancel(); |
| timer = null; |
| } |
| |
| controller = new StreamController( |
| onListen: startTimer, |
| onPause: stopTimer, |
| onResume: startTimer, |
| onCancel: stopTimer); |
| |
| return controller.stream; |
| } |