[mdv] Implement two-way binding to HTMLTextArea.value

pkg/mdv/lib/src/bindings.dart

Index: pkg/mdv/lib/src/bindings.dart
diff --git a/pkg/mdv/lib/src/bindings.dart b/pkg/mdv/lib/src/bindings.dart
deleted file mode 100644
index 1605a1ee246dbc5922b74b5d52506d8949b1ea29..0000000000000000000000000000000000000000
--- a/pkg/mdv/lib/src/bindings.dart
+++ /dev/null
@@ -1,430 +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.
-
-part of mdv;
-
-// This code is a port of Model-Driven-Views:
-// https://github.com/polymer-project/mdv
-// The code mostly comes from src/template_element.js
-
-typedef void _ChangeHandler(value);
-
-abstract class _InputBinding {
-  // InputElement or SelectElement
-  final element;
-  PathObserver binding;
-  StreamSubscription _pathSub;
-  StreamSubscription _eventSub;
-
-  _InputBinding(this.element, model, String path) {
-    binding = new PathObserver(model, path);
-    _pathSub = binding.bindSync(valueChanged);
-    _eventSub = _getStreamForInputType(element).listen(updateBinding);
-  }
-
-  void valueChanged(newValue);
-
-  void updateBinding(e);
-
-  void unbind() {
-    binding = null;
-    _pathSub.cancel();
-    _eventSub.cancel();
-  }
-
-  static EventStreamProvider<Event> _checkboxEventType = () {
-    // Attempt to feature-detect which event (change or click) is fired first
-    // for checkboxes.
-    var div = new DivElement();
-    var checkbox = div.append(new InputElement());
-    checkbox.type = 'checkbox';
-    var fired = [];
-    checkbox.onClick.listen((e) {
-      fired.add(Element.clickEvent);
-    });
-    checkbox.onChange.listen((e) {
-      fired.add(Element.changeEvent);
-    });
-    checkbox.dispatchEvent(new MouseEvent('click', view: window));
-    // WebKit/Blink don't fire the change event if the element is outside the
-    // document, so assume 'change' for that case.
-    return fired.length == 1 ? Element.changeEvent : fired.first;
-  }();
-
-  static Stream<Event> _getStreamForInputType(element) {
-    switch (element.type) {
-      case 'checkbox':
-        return _checkboxEventType.forTarget(element);
-      case 'radio':
-      case 'select-multiple':
-      case 'select-one':
-        return element.onChange;
-      default:
-        return element.onInput;
-    }
-  }
-}
-
-
-// TODO(jmesserly): not sure what kind of boolean conversion rules to
-// apply for template data-binding. HTML attributes are true if they're
-// present. However Dart only treats "true" as true. Since this is HTML we'll
-// use something closer to the HTML rules: null (missing) and false are false,
-// everything else is true. See: https://github.com/polymer-project/mdv/issues/59
-bool _toBoolean(value) => null != value && false != value;
-
-Node _createDeepCloneAndDecorateTemplates(Node node, String syntax) {
-  var clone = node.clone(false); // Shallow clone.
-  if (clone is Element && clone.isTemplate) {
-    TemplateElement.decorate(clone, node);
-    if (syntax != null) {
-      clone.attributes.putIfAbsent('syntax', () => syntax);
-    }
-  }
-
-  for (var c = node.firstChild; c != null; c = c.nextNode) {
-    clone.append(_createDeepCloneAndDecorateTemplates(c, syntax));
-  }
-  return clone;
-}
-
-void _addBindings(Node node, model, [CustomBindingSyntax delegate]) {
-  if (node is Element) {
-    _addAttributeBindings(node, model, delegate);
-  } else if (node is Text) {
-    _parseAndBind(node, 'text', node.text, model, delegate);
-  }
-
-  for (var c = node.firstChild; c != null; c = c.nextNode) {
-    _addBindings(c, model, delegate);
-  }
-}
-
-void _addAttributeBindings(Element element, model, delegate) {
-  element.attributes.forEach((name, value) {
-    if (value == '' && (name == 'bind' || name == 'repeat')) {
-      value = '{{}}';
-    }
-    _parseAndBind(element, name, value, model, delegate);
-  });
-}
-
-void _parseAndBind(Node node, String name, String text, model,
-    CustomBindingSyntax delegate) {
-
-  var tokens = _parseMustacheTokens(text);
-  if (tokens.length == 0 || (tokens.length == 1 && tokens[0].isText)) {
-    return;
-  }
-
-  // If this is a custom element, give the .xtag a change to bind.
-  node = _nodeOrCustom(node);
-
-  if (tokens.length == 1 && tokens[0].isBinding) {
-    _bindOrDelegate(node, name, model, tokens[0].value, delegate);
-    return;
-  }
-
-  var replacementBinding = new CompoundBinding();
-  for (var i = 0; i < tokens.length; i++) {
-    var token = tokens[i];
-    if (token.isBinding) {
-      _bindOrDelegate(replacementBinding, i, model, token.value, delegate);
-    }
-  }
-
-  replacementBinding.combinator = (values) {
-    var newValue = new StringBuffer();
-
-    for (var i = 0; i < tokens.length; i++) {
-      var token = tokens[i];
-      if (token.isText) {
-        newValue.write(token.value);
-      } else {
-        var value = values[i];
-        if (value != null) {
-          newValue.write(value);
-        }
-      }
-    }
-
-    return newValue.toString();
-  };
-
-  node.bind(name, replacementBinding, 'value');
-}
-
-void _bindOrDelegate(node, name, model, String path,
-    CustomBindingSyntax delegate) {
-
-  if (delegate != null) {
-    var delegateBinding = delegate.getBinding(model, path, name, node);
-    if (delegateBinding != null) {
-      model = delegateBinding;
-      path = 'value';
-    }
-  }
-
-  node.bind(name, model, path);
-}
-
-/**
- * Gets the [node]'s custom [Element.xtag] if present, otherwise returns
- * the node. This is used so nodes can override [Node.bind], [Node.unbind],
- * and [Node.unbindAll] like InputElement does.
- */
-// TODO(jmesserly): remove this when we can extend Element for real.
-_nodeOrCustom(node) => node is Element ? node.xtag : node;
-
-List<_BindingToken> _parseMustacheTokens(String s) {
-  var result = [];
-  var length = s.length;
-  var index = 0, lastIndex = 0;
-  while (lastIndex < length) {
-    index = s.indexOf('{{', lastIndex);
-    if (index < 0) {
-      result.add(new _BindingToken(s.substring(lastIndex)));
-      break;
-    } else {
-      // There is a non-empty text run before the next path token.
-      if (index > 0 && lastIndex < index) {
-        result.add(new _BindingToken(s.substring(lastIndex, index)));
-      }
-      lastIndex = index + 2;
-      index = s.indexOf('}}', lastIndex);
-      if (index < 0) {
-        var text = s.substring(lastIndex - 2);
-        if (result.length > 0 && result.last.isText) {
-          result.last.value += text;
-        } else {
-          result.add(new _BindingToken(text));
-        }
-        break;
-      }
-
-      var value = s.substring(lastIndex, index).trim();
-      result.add(new _BindingToken(value, isBinding: true));
-      lastIndex = index + 2;
-    }
-  }
-  return result;
-}
-
-void _addTemplateInstanceRecord(fragment, model) {
-  if (fragment.firstChild == null) {
-    return;
-  }
-
-  var instanceRecord = new TemplateInstance(
-      fragment.firstChild, fragment.lastChild, model);
-
-  var node = instanceRecord.firstNode;
-  while (node != null) {
-    _mdv(node)._templateInstance = instanceRecord;
-    node = node.nextNode;
-  }
-}
-
-class _BindingToken {
-  final String value;
-  final bool isBinding;
-
-  _BindingToken(this.value, {this.isBinding: false});
-
-  bool get isText => !isBinding;
-}
-
-class _TemplateIterator {
-  final Element _templateElement;
-  final List<Node> terminators = [];
-  final CompoundBinding inputs;
-  List iteratedValue;
-  Object _lastValue;
-
-  StreamSubscription _sub;
-  StreamSubscription _valueBinding;
-
-  _TemplateIterator(this._templateElement)
-      : inputs = new CompoundBinding(resolveInputs) {
-
-    _valueBinding = new PathObserver(inputs, 'value').bindSync(valueChanged);
-  }
-
-  static Object resolveInputs(Map values) {
-    if (values.containsKey('if') && !_toBoolean(values['if'])) {
-      return null;
-    }
-
-    if (values.containsKey('repeat')) {
-      return values['repeat'];
-    }
-
-    if (values.containsKey('bind')) {
-      return [values['bind']];
-    }
-
-    return null;
-  }
-
-  void valueChanged(value) {
-    // TODO(jmesserly): should PathObserver do this for us?
-    var oldValue = _lastValue;
-    _lastValue = value;
-
-    if (value is! List) {
-      value = [];
-    }
-
-    unobserve();
-    iteratedValue = value;
-
-    if (value is Observable) {
-      _sub = value.changes.listen(_handleChanges);
-    }
-
-    int addedCount = iteratedValue.length;
-    var removedCount = oldValue is List ? (oldValue as List).length : 0;
-    if (addedCount == 0 && removedCount == 0) return; // nothing to do.
-
-    _handleChanges([new ListChangeRecord(0, addedCount: addedCount,
-        removedCount: removedCount)]);
-  }
-
-  Node getTerminatorAt(int index) {
-    if (index == -1) return _templateElement;
-    var terminator = terminators[index];
-    if (terminator is Element && (terminator as Element).isTemplate) {
-      var subIterator = _mdv(terminator)._templateIterator;
-      if (subIterator != null) {
-        return subIterator.getTerminatorAt(subIterator.terminators.length - 1);
-      }
-    }
-
-    return terminator;
-  }
-
-  void insertInstanceAt(int index, List<Node> instanceNodes) {
-    var previousTerminator = getTerminatorAt(index - 1);
-    var terminator = instanceNodes.length > 0 ? instanceNodes.last
-        : previousTerminator;
-
-    terminators.insert(index, terminator);
-
-    var parent = _templateElement.parentNode;
-    var insertBeforeNode = previousTerminator.nextNode;
-    for (var node in instanceNodes) {
-      parent.insertBefore(node, insertBeforeNode);
-    }
-  }
-
-  List<Node> extractInstanceAt(int index) {
-    var instanceNodes = <Node>[];
-    var previousTerminator = getTerminatorAt(index - 1);
-    var terminator = getTerminatorAt(index);
-    terminators.removeAt(index);
-
-    var parent = _templateElement.parentNode;
-    while (terminator != previousTerminator) {
-      var node = terminator;
-      terminator = node.previousNode;
-      node.remove();
-      instanceNodes.add(node);
-    }
-    return instanceNodes;
-  }
-
-  getInstanceModel(model, String syntax) {
-    var delegate = TemplateElement.syntax[syntax];
-    if (delegate != null) {
-      return delegate.getInstanceModel(_templateElement, model);
-    }
-    return model;
-  }
-
-  List<Node> getInstanceNodes(model, String syntax, IdentityMap instanceCache) {
-    var instanceNodes = instanceCache.remove(model);
-    if (instanceNodes != null) return instanceNodes;
-
-    var fragment = _templateElement.createInstance(model, syntax);
-    instanceNodes = fragment.nodes.toList();
-    fragment.nodes.clear();
-    return instanceNodes;
-  }
-
-  void _handleChanges(Iterable<ChangeRecord> splices) {
-    splices = splices.where((s) => s is ListChangeRecord);
-
-    var template = _templateElement;
-    var syntax = template.attributes['syntax'];
-
-    if (template.parentNode == null || template.document.window == null) {
-      abandon();
-      // TODO(jmesserly): MDV calls templateIteratorTable.delete(this) here,
-      // but I think that's a no-op because only nodes are used as keys.
-      // See https://github.com/Polymer/mdv/pull/114.
-      return;
-    }
-
-    // TODO(jmesserly): IdentityMap matches JS semantics, but it's O(N) right
-    // now. See http://dartbug.com/4161.
-    var instanceCache = new IdentityMap();
-    var removeDelta = 0;
-    for (var splice in splices) {
-      for (int i = 0; i < splice.removedCount; i++) {
-        var instanceNodes = extractInstanceAt(splice.index + removeDelta);
-        var model = _mdv(instanceNodes.first)._templateInstance.model;
-        instanceCache[model] = instanceNodes;
-      }
-
-      removeDelta -= splice.addedCount;
-    }
-
-    for (var splice in splices) {
-      for (var addIndex = splice.index;
-          addIndex < splice.index + splice.addedCount;
-          addIndex++) {
-
-        var model = getInstanceModel(iteratedValue[addIndex], syntax);
-
-        var instanceNodes = getInstanceNodes(model, syntax, instanceCache);
-        insertInstanceAt(addIndex, instanceNodes);
-      }
-    }
-
-    for (var instanceNodes in instanceCache.values) {
-      instanceNodes.forEach(_unbindAllRecursively);
-    }
-  }
-
-  void unobserve() {
-    if (_sub == null) return;
-    _sub.cancel();
-    _sub = null;
-  }
-
-  void abandon() {
-    unobserve();
-    _valueBinding.cancel();
-    terminators.clear();
-    inputs.dispose();
-  }
-
-  static void _unbindAllRecursively(Node node) {
-    var nodeExt = _mdv(node);
-    nodeExt._templateInstance = null;
-    if (node is Element && (node as Element).isTemplate) {
-      // Make sure we stop observing when we remove an element.
-      var templateIterator = nodeExt._templateIterator;
-      if (templateIterator != null) {
-        templateIterator.abandon();
-        nodeExt._templateIterator = null;
-      }
-    }
-
-    _nodeOrCustom(node).unbindAll();
-    for (var c = node.firstChild; c != null; c = c.nextNode) {
-      _unbindAllRecursively(c);
-    }
-  }
-}