| // Copyright (c) 2017, 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'; |
| |
| /// A function that returns the current [DateTime]. |
| typedef DateTime _Clock(); |
| DateTime _defaultClock() => DateTime.now(); |
| |
| const _ZoneKey = #timing_Clock; |
| |
| /// Returns the current [DateTime]. |
| /// |
| /// May be overridden for tests using [scopeClock]. |
| DateTime now() => (Zone.current[_ZoneKey] as _Clock ?? _defaultClock)(); |
| |
| /// Runs [f], with [clock] scoped whenever [now] is called. |
| T scopeClock<T>(DateTime clock(), T f()) => |
| runZoned(f, zoneValues: {_ZoneKey: clock}); |
