dart-sdk/tests/lib/async/zone_register_callback_unary_test.dart
Robert Nystrom a2b556b937 Migrate lib_2/async to NNBD.
Change-Id: Ia5c41dda6503e1fbb8cc6099835d07588425e2ba
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/128310
Commit-Queue: Bob Nystrom <rnystrom@google.com>
Auto-Submit: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>
2020-01-09 22:04:37 +00:00

40 lines
1.4 KiB
Dart

// Copyright (c) 2013, 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 'package:expect/expect.dart';
import 'package:async_helper/async_helper.dart';
import 'dart:async';
main() {
Completer done = new Completer();
var valueToCapture;
var restoredValue;
Expect.identical(Zone.root, Zone.current);
Zone forked = Zone.current.fork(specification: new ZoneSpecification(
registerUnaryCallback:
<R, T>(Zone self, ZoneDelegate parent, Zone origin, R f(T arg)) {
// The zone is still the same as when origin.run was invoked, which
// is the root zone. (The origin zone hasn't been set yet).
Expect.identical(Zone.current, Zone.root);
// Note that not forwarding is completely legal, though not encouraged.
var capturedValue = valueToCapture;
return parent.registerUnaryCallback(origin, (arg) {
restoredValue = capturedValue;
return f(arg);
});
}));
valueToCapture = 499;
var fun = (x) => x + 99;
var registered = forked.registerUnaryCallback(fun);
Expect.isFalse(identical(fun, registered));
// It is valid to invoke the callback in a different zone. This is, of course,
// extremely discouraged.
var result = registered(399);
Expect.equals(498, result);
Expect.equals(499, restoredValue);
}