| // 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. |
| |
| /** |
| * *Warning*: this library is **internal**, and APIs are subject to change. |
| * |
| * Tracks observable objects for dirty checking and testing purposes. |
| * |
| * It can collect all observed objects, which can be used to trigger predictable |
| * delivery of all pending changes in a test, including objects allocated |
| * internally to another library, such as those in `package:mdv`. |
| */ |
| library observe.src.dirty_check; |
| |
| import 'package:logging/logging.dart'; |
| import 'package:observe/observe.dart' show Observable; |
| |
| /** The number of active observables in the system. */ |
| int get allObservablesCount => _allObservablesCount; |
| |
| int _allObservablesCount = 0; |
| |
| List<Observable> _allObservables = null; |
| |
| bool _delivering = false; |
| |
| void registerObservable(Observable obj) { |
| if (_allObservables == null) _allObservables = <Observable>[]; |
| _allObservables.add(obj); |
| _allObservablesCount++; |
| } |
| |
| /** |
| * Synchronously deliver all change records for known observables. |
| * |
| * This will execute [Observable.deliverChanges] on objects that inherit from |
| * [ObservableMixin]. |
| */ |
| // Note: this is called performMicrotaskCheckpoint in change_summary.js. |
| void dirtyCheckObservables() { |
| if (_delivering) return; |
| if (_allObservables == null) return; |
| |
| _delivering = true; |
| |
| int cycles = 0; |
| bool anyChanged = false; |
| List debugLoop = null; |
| do { |
| cycles++; |
| if (cycles == MAX_DIRTY_CHECK_CYCLES) { |
| debugLoop = []; |
| } |
| |
| var toCheck = _allObservables; |
| _allObservables = <Observable>[]; |
| anyChanged = false; |
| |
| for (int i = 0; i < toCheck.length; i++) { |
| final observer = toCheck[i]; |
| if (observer.hasObservers) { |
| if (observer.deliverChanges()) { |
| anyChanged = true; |
| if (debugLoop != null) debugLoop.add([i, observer]); |
| } |
| _allObservables.add(observer); |
| } |
| } |
| } while (cycles < MAX_DIRTY_CHECK_CYCLES && anyChanged); |
| |
| if (debugLoop != null && anyChanged) { |
| _logger.warning('Possible loop in Observable.dirtyCheck, stopped ' |
| 'checking.'); |
| for (final info in debugLoop) { |
| _logger.warning('In last iteration Observable changed at index ' |
| '${info[0]}, object: ${info[1]}.'); |
| } |
| } |
| |
| _allObservablesCount = _allObservables.length; |
| _delivering = false; |
| } |
| |
| const MAX_DIRTY_CHECK_CYCLES = 1000; |
| |
| |
| /** |
| * Log for messages produced at runtime by this library. Logging can be |
| * configured by accessing Logger.root from the logging library. |
| */ |
| final Logger _logger = new Logger('Observable.dirtyCheck'); |