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// 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) {
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() {
if (timer != null) {
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() {
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() {
if (timer != null) {
timer.cancel();
timer = null;
}
}
controller = new StreamController(
onListen: startTimer,
onPause: stopTimer,
onResume: startTimer,
onCancel: stopTimer);
return controller.stream;
}