Reorganize mdv and observe packages

pkg/mdv/lib/mdv.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.
+
+// TODO(jmesserly): more commentary here.
+/**
+ * This library provides access to Model-Driven-Views APIs on HTML elements.
+ * More information can be found at: <https://github.com/toolkitchen/mdv>.
+ */
+library mdv;
+
+import 'dart:async';
+import 'dart:collection';
+import 'dart:html';
+import 'dart:math' as math;
+import 'package:observe/observe.dart';
+
+part 'src/bindings.dart';
+part 'src/element.dart';
+part 'src/input_element.dart';
+part 'src/node.dart';
+part 'src/template.dart';
+part 'src/text.dart';
+
+/** Initialize the Model-Driven Views polyfill. */
+void initialize() {
+  mdvPackage = _mdv;
+}
+
+StreamController<DocumentFragment> _instanceCreated;
+
+/**
+ * *Warning*: This is an implementation helper for Model-Driven Views and
+ * should not be used in your code.
+ *
+ * This event is fired whenever a template is instantiated via
+ * [Element.createInstance].
+ */
+// TODO(rafaelw): This is a hack, and is neccesary for the polyfill
+// because custom elements are not upgraded during clone()
+Stream<DocumentFragment> get instanceCreated {
+  if (_instanceCreated == null) {
+    _instanceCreated =
+        new StreamController<DocumentFragment>(sync: true);
+  }
+  return _instanceCreated.stream;
+}
+
+/**
+ * Binds all mustaches recursively starting from the [root] node.
+ *
+ * Note: this is not an official Model-Driven-Views API; it is intended to
+ * support binding the [ShadowRoot]'s content to a model.
+ */
+// TODO(jmesserly): this is needed to avoid two <template> nodes when using
+// bindings in a custom element's template. See also:
+// https://github.com/polymer-project/polymer/blob/master/src/bindMDV.js#L68
+// Called from:
+// https://github.com/polymer-project/polymer/blob/master/src/register.js#L99
+void bindModel(Node root, model, [CustomBindingSyntax syntax]) {
+  _Bindings._addBindings(root, model, syntax);
+}
+
+
+// TODO(jmesserly): investigate if expandos give us enough performance.
+
+// The expando for storing our MDV wrappers.
+//
+// In general, we need state associated with the nodes. Rather than having a
+// bunch of individual expandos, we keep one per node.
+//
+// Aside from the potentially helping performance, it also keeps things simpler
+// if we decide to integrate MDV into the DOM later, and means less code needs
+// to worry about expandos.
+final Expando _mdvExpando = new Expando('mdv');
+
+_mdv(node) {
+  var wrapper = _mdvExpando[node];
+  if (wrapper != null) return wrapper;
+
+  // TODO(jmesserly): is using nodeType and localName faster than "is"?

[floitsch, 2013/06/26 18:06:39]

`is` should be fast. Afaik dart2js compiles it to a simple method invocation,
and in the VM it isn't slow either.

[Jennifer Messerly, 2013/06/26 23:09:12]

thanks for the info! removed TODO.

+  if (node is InputElement) {
+    wrapper = new _InputElementExtension(node);
+  } else if (node is Element) {
+    if (node.isTemplate) {
+      wrapper = new _TemplateExtension(node);
+    } else {
+      wrapper = new _ElementExtension(node);
+    }
+  } else if (node is Text) {
+    wrapper = new _TextExtension(node);
+  } else if (node is Node) {
+    wrapper = new _NodeExtension(node);
+  } else {
+    // TODO(jmesserly): this happens for things like CompoundBinding.
+    wrapper = node;
+  }
+
+  _mdvExpando[node] = wrapper;
+  return wrapper;
+}