introduce ObservableList.listChanges to keep list changes separate from property changes

pkg/template_binding/lib/src/template_iterator.dart

 // 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.
 
 part of template_binding;
 
 // This code is a port of what was formerly known as Model-Driven-Views, now
 // located at:
 //     https://github.com/polymer/TemplateBinding
 //     https://github.com/polymer/NodeBind
@@ skipping 226 matching lines @@
    */
   final List terminators = [];
   List iteratedValue;
   bool closed = false;
   bool depsChanging = false;
 
   bool hasRepeat = false, hasBind = false, hasIf = false;
   Object repeatModel, bindModel, ifModel;
   String repeatPath, bindPath, ifPath;
 
-  StreamSubscription _valueSub, _arraySub;
+  StreamSubscription _valueSub, _listSub;
 
   bool _initPrepareFunctions = false;
   PrepareInstanceModelFunction _instanceModelFn;
   PrepareInstancePositionChangedFunction _instancePositionChangedFn;
 
   _TemplateIterator(this._templateExt);
 
   Element get _templateElement => _templateExt._node;
 
   resolve() {
@@ skipping 48 matching lines @@
       iteratedValue = newValue;
     } else if (newValue is Iterable) {
       // Dart note: we support Iterable by calling toList.
       // But we need to be careful to observe the original iterator if it
       // supports that.
       iteratedValue = (newValue as Iterable).toList();
     } else {
       iteratedValue = null;
     }
 
-    if (iteratedValue != null && newValue is Observable) {
-      _arraySub = (newValue as Observable).changes.listen(
-          _handleSplices);
+    if (iteratedValue != null && newValue is ObservableList) {
+      _listSub = newValue.listChanges.listen(_handleSplices);
     }
 
-    var splices = calculateSplices(
-        iteratedValue != null ? iteratedValue : [],
-        oldValue != null ? oldValue : []);
+    var splices = ObservableList.calculateChangeRecords(
+        oldValue != null ? oldValue : [],
+        iteratedValue != null ? iteratedValue : []);
 
     if (splices.isNotEmpty) _handleSplices(splices);
   }
 
   Node getTerminatorAt(int index) {
     if (index == -1) return _templateElement;
     var terminator = terminators[index * 2];
     if (!isSemanticTemplate(terminator) ||
         identical(terminator, _templateElement)) {
       return terminator;
@@ skipping 42 matching lines @@
     var parent = _templateElement.parentNode;
     while (terminator != previousTerminator) {
       var node = previousTerminator.nextNode;
       if (node == terminator) terminator = previousTerminator;
       node.remove();
       instanceNodes.add(node);
     }
     return new _BoundNodes(instanceNodes, bound);
   }
 
-  void _handleSplices(Iterable<ChangeRecord> splices) {
+  void _handleSplices(List<ListChangeRecord> splices) {
     if (closed) return;
 
-    splices = splices.where((s) => s is ListChangeRecord);
-
     final template = _templateElement;
     final delegate = _templateExt._self.bindingDelegate;
 
     if (template.parentNode == null || template.ownerDocument.window == null) {
       close();
       return;
     }
 
     // Dart note: the JavaScript code relies on the distinction between null
     // and undefined to track whether the functions are prepared. We use a bool.
     if (!_initPrepareFunctions) {
       _initPrepareFunctions = true;
       if (delegate != null) {
         _instanceModelFn = delegate.prepareInstanceModel(template);
         _instancePositionChangedFn =
             delegate.prepareInstancePositionChanged(template);
       }
     }
 
     var instanceCache = new HashMap<Object, _BoundNodes>(equals: identical);
     var removeDelta = 0;
     for (var splice in splices) {
-      for (int i = 0; i < splice.removedCount; i++) {
-        var instance = extractInstanceAt(splice.index + removeDelta);
-        if (instance.nodes.length == 0) continue;
-        var model = nodeBind(instance.nodes.first).templateInstance.model;
-        instanceCache[model] = instance;
+      for (var model in splice.removed) {
+        instanceCache[model] = extractInstanceAt(splice.index + removeDelta);
       }
 
       removeDelta -= splice.addedCount;
     }
 
     for (var splice in splices) {
       for (var addIndex = splice.index;
           addIndex < splice.index + splice.addedCount;
           addIndex++) {
 
@@ skipping 34 matching lines @@
     }
 
     // We must use the first node of the instance, because any subsequent
     // nodes may have been generated by sub-templates.
     // TODO(rafaelw): This is brittle WRT instance mutation -- e.g. if the
     // first node was removed by script.
     var instance = nodeBind(previousTerminator.nextNode).templateInstance;
     _instancePositionChangedFn(instance, index);
   }
 
-  void reportInstancesMoved(Iterable<ChangeRecord> splices) {
+  void reportInstancesMoved(List<ListChangeRecord> splices) {
     var index = 0;
     var offset = 0;
-    for (ListChangeRecord splice in splices) {
+    for (var splice in splices) {
       if (offset != 0) {
         while (index < splice.index) {
           reportInstanceMoved(index);
           index++;
         }
       } else {
         index = splice.index;
       }
 
       while (index < splice.index + splice.addedCount) {
         reportInstanceMoved(index);
         index++;
       }
 
-      offset += splice.addedCount - splice.removedCount;
+      offset += splice.addedCount - splice.removed.length;
     }
 
     if (offset == 0) return;
 
     var length = terminators.length ~/ 2;
     while (index < length) {
       reportInstanceMoved(index);
       index++;
     }
   }
 
   void closeInstanceBindings(List<NodeBinding> bound) {
     for (var binding in bound) binding.close();
   }
 
   void unobserve() {
-    if (_arraySub == null) return;
-    _arraySub.cancel();
-    _arraySub = null;
+    if (_listSub == null) return;
+    _listSub.cancel();
+    _listSub = null;
   }
 
   void close() {
     if (closed) return;
 
     unobserve();
     for (var i = 1; i < terminators.length; i += 2) {
       closeInstanceBindings(terminators[i]);
     }
 
     terminators.clear();
     if (_valueSub != null) {
       _valueSub.cancel();
       _valueSub = null;
     }
     _templateExt._iterator = null;
     closed = true;
   }
 }
 
 // Dart note: the JavaScript version just puts an expando on the array.
 class _BoundNodes {
   final List<Node> nodes;
   final List<NodeBinding> bound;
   _BoundNodes(this.nodes, this.bound);
 }