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| 1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. |
| 4 |
| 5 /** |
| 6 * *Warning*: this library is **internal**, and APIs are subject to change. |
| 7 * |
| 8 * Tracks observable objects for dirty checking and testing purposes. |
| 9 * |
| 10 * It can collect all observed objects, which can be used to trigger predictable |
| 11 * delivery of all pending changes in a test, including objects allocated |
| 12 * internally to another library, such as those in `package:mdv`. |
| 13 */ |
| 14 library observe.src.watcher; |
| 15 |
| 16 import 'package:observe/observe.dart' show Observable; |
| 17 |
| 18 /** The number of active observables in the system. */ |
| 19 int get allObservablesCount => _allObservablesCount; |
| 20 |
| 21 int _allObservablesCount = 0; |
| 22 |
| 23 List<Observable> _allObservables = null; |
| 24 |
| 25 bool _delivering = false; |
| 26 |
| 27 void registerObservable(Observable obj) { |
| 28 if (_allObservables == null) _allObservables = <Observable>[]; |
| 29 _allObservables.add(obj); |
| 30 _allObservablesCount++; |
| 31 } |
| 32 |
| 33 /** |
| 34 * Synchronously deliver all change records for known observables. |
| 35 * |
| 36 * This will execute [Observable.deliverChanges] on objects that inherit from |
| 37 * [ObservableMixin]. |
| 38 */ |
| 39 // Note: this is called performMicrotaskCheckpoint in change_summary.js. |
| 40 void dirtyCheck() { |
| 41 if (_delivering) return; |
| 42 if (_allObservables == null) return; |
| 43 |
| 44 _delivering = true; |
| 45 |
| 46 int cycles = 0; |
| 47 bool anyChanged = false; |
| 48 do { |
| 49 cycles++; |
| 50 var toCheck = _allObservables; |
| 51 _allObservables = <Observable>[]; |
| 52 anyChanged = false; |
| 53 |
| 54 for (final observer in toCheck) { |
| 55 if (observer.hasObservers) { |
| 56 anyChanged = anyChanged || observer.deliverChanges(); |
| 57 _allObservables.add(observer); |
| 58 } |
| 59 } |
| 60 } while (cycles < _MAX_DIRTY_CHECK_CYCLES && anyChanged); |
| 61 |
| 62 // TODO(jmesserly): warn if limit is reached? |
| 63 |
| 64 _allObservablesCount = _allObservables.length; |
| 65 _delivering = false; |
| 66 } |
| 67 |
| 68 var _MAX_DIRTY_CHECK_CYCLES = 1000; |
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