big update to observe, template_binding, polymer

pkg/observe/lib/src/compound_path_observer.dart

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();
-}