| // Copyright (c) 2012, 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. |
| |
| part of dart.async; |
| |
| abstract class Timer { |
| // Internal list used to group Timer.run callbacks. |
| static List _runCallbacks = []; |
| |
| /** |
| * Creates a new timer. |
| * |
| * The [callback] callback is invoked after the given [duration]. |
| * A negative duration is treated similar to a duration of 0. |
| * |
| * If the [duration] is statically known to be 0, consider using [run]. |
| * |
| * Frequently the [duration] is either a constant or computed as in the |
| * following example (taking advantage of the multiplication operator of |
| * the Duration class): |
| * |
| * const TIMEOUT = const Duration(seconds: 3); |
| * const ms = const Duration(milliseconds: 1); |
| * |
| * startTimeout([int milliseconds]) { |
| * var duration = milliseconds == null ? TIMEOUT : ms * milliseconds; |
| * return new Timer(duration, handleTimeout); |
| * } |
| * |
| * Note: If Dart code using Timer is compiled to JavaScript, the finest |
| * granularity available in the browser is 4 milliseconds. |
| */ |
| external factory Timer(Duration duration, void callback()); |
| |
| /** |
| * Creates a new repeating timer. |
| * |
| * The [callback] is invoked repeatedly with [duration] intervals until |
| * canceled. A negative duration is treated similar to a duration of 0. |
| */ |
| external factory Timer.periodic(Duration duration, |
| void callback(Timer timer)); |
| |
| /** |
| * Runs the given [callback] asynchronously as soon as possible. |
| */ |
| static void run(void callback()) { |
| // Optimizing a group of Timer.run callbacks to be executed in the |
| // same Timer callback. |
| _runCallbacks.add(callback); |
| if (_runCallbacks.length == 1) { |
| new Timer(const Duration(milliseconds: 0), () { |
| List runCallbacks = _runCallbacks; |
| // Create new list to make sure we don't call newly added callbacks in |
| // this event. |
| _runCallbacks = []; |
| for (int i = 0; i < runCallbacks.length; i++) { |
| Function callback = runCallbacks[i]; |
| try { |
| callback(); |
| } catch (e) { |
| List newCallbacks = _runCallbacks; |
| _runCallbacks = []; |
| i++; // Skip the current; |
| _runCallbacks.addAll( |
| runCallbacks.sublist(i)); |
| _runCallbacks.addAll(newCallbacks); |
| throw; |
| } |
| } |
| }); |
| } |
| } |
| |
| /** |
| * Cancels the timer. |
| */ |
| void cancel(); |
| } |