Index: pkg/observe/lib/src/compound_path_observer.dart |
diff --git a/pkg/observe/lib/src/compound_path_observer.dart b/pkg/observe/lib/src/compound_path_observer.dart |
deleted file mode 100644 |
index 1594e082c5b1bbddc5efe12f488454675eb06600..0000000000000000000000000000000000000000 |
--- a/pkg/observe/lib/src/compound_path_observer.dart |
+++ /dev/null |
@@ -1,115 +0,0 @@ |
-// 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. |
- |
-library observe.src.compound_path_observer; |
- |
-import 'dart:async'; |
-import 'package:observe/observe.dart'; |
- |
-/** |
- * CompoundPathObserver is an object which knows how to listen to multiple path |
- * values (registered via [addPath]) and invoke a function when one or more |
- * of the values have changed. The result of this function will be set into the |
- * [value] property. When any value has changed, all current values are provided |
- * to the function in the single `values` argument. |
- * |
- * For example: |
- * |
- * var binding = new CompoundPathObserver(computeValue: (values) { |
- * var combinedValue; |
- * // compute combinedValue based on the current values which are provided |
- * return combinedValue; |
- * }); |
- * binding.addPath(obj1, path1); |
- * binding.addPath(obj2, path2); |
- * //... |
- * binding.addPath(objN, pathN); |
- */ |
-// TODO(jmesserly): this isn't a full port of CompoundPathObserver. It is only |
-// what was needed for TemplateBinding. |
-class CompoundPathObserver extends ChangeNotifier { |
- List<PathObserver> _observers = []; |
- List<StreamSubscription> _subs = []; |
- Object _value; // the last computed value |
- |
- // TODO(jmesserly): this is public in observe.js |
- final Function _computeValue; |
- |
- bool _started = false; |
- |
- /** True if [start] has been called, otherwise false. */ |
- bool get started => _started; |
- |
- bool _scheduled = false; |
- |
- /** |
- * Creates a new observer, optionally proving the [computeValue] function |
- * for computing the value. You can also set [schedule] to true if you plan |
- * to invoke [resolve] manually after initial construction of the binding. |
- */ |
- CompoundPathObserver({computeValue(List values)}) |
- : _computeValue = computeValue; |
- |
- int get length => _observers.length; |
- |
- @reflectable get value => _value; |
- |
- void addPath(model, String path) { |
- if (_started) { |
- throw new StateError('Cannot add more paths once started.'); |
- } |
- |
- _observers.add(new PathObserver(model, path)); |
- } |
- |
- void start() { |
- if (_started) return; |
- _started = true; |
- |
- final scheduleResolve = _scheduleResolve; |
- for (var observer in _observers) { |
- _subs.add(observer.changes.listen(scheduleResolve)); |
- } |
- _resolve(); |
- } |
- |
- // TODO(rafaelw): Is this the right processing model? |
- // TODO(rafaelw): Consider having a seperate ChangeSummary for |
- // CompoundBindings so to excess dirtyChecks. |
- void _scheduleResolve(_) { |
- if (_scheduled) return; |
- _scheduled = true; |
- scheduleMicrotask(_resolve); |
- } |
- |
- void _resolve() { |
- _scheduled = false; |
- if (_observers.isEmpty) return; |
- var newValue = _observers.map((o) => o.value).toList(); |
- if (_computeValue != null) newValue = _computeValue(newValue); |
- _value = notifyPropertyChange(#value, _value, newValue); |
- } |
- |
- /** |
- * Closes the observer. |
- * |
- * This happens automatically if the [value] property is no longer observed, |
- * but this can also be called explicitly. |
- */ |
- void close() { |
- if (_observers.isEmpty) return; |
- |
- if (_started) { |
- for (StreamSubscription sub in _subs) { |
- sub.cancel(); |
- } |
- } |
- _observers.clear(); |
- _subs.clear(); |
- _value = null; |
- } |
- |
- observed() => start(); |
- unobserved() => close(); |
-} |