Reorganize mdv and observe packages

pkg/mdv_observe/lib/src/observable_map.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 mdv_observe;
-
-// TODO(jmesserly): this needs to be faster. We currently require multiple
-// lookups per key to get the old value.
-// TODO(jmesserly): this doesn't implement the precise interfaces like
-// LinkedHashMap, SplayTreeMap or HashMap. However it can use them for the
-// backing store.
-
-// TODO(jmesserly): should we summarize map changes like we do for list changes?
-class MapChangeRecord extends ChangeRecord {
-  /** The map key that changed. */
-  final key;
-
-  // TODO(jmesserly): we could store this more compactly if it matters.
-  /** True if this key was inserted. */
-  final bool isInsert;
-
-  /** True if this key was removed. */
-  final bool isRemove;
-
-  MapChangeRecord(this.key, {this.isInsert: false, this.isRemove: false}) {
-    if (isInsert && isRemove) {
-      throw new ArgumentError(
-          '$key cannot be inserted and removed in the same change');
-    }
-  }
-
-  // Use == on the key, to match equality semantics of most Maps.
-  bool changes(otherKey) => key == otherKey;
-
-  String toString() {
-    var kind = isInsert ? 'insert' : isRemove ? 'remove' : 'set';
-    return '#<MapChangeRecord $kind $key>';
-  }
-}
-
-/**
- * Represents an observable map of model values. If any items are added,
- * removed, or replaced, then observers that are listening to [changes]
- * will be notified.
- */
-class ObservableMap<K, V> extends ObservableBase implements Map<K, V> {
-  static const _LENGTH = const Symbol('length');
-
-  final Map<K, V> _map;
-
-  /** Creates an observable map. */
-  ObservableMap() : _map = new HashMap<K, V>();
-
-  /** Creates a new observable map using a [LinkedHashMap]. */
-  ObservableMap.linked() : _map = new LinkedHashMap<K, V>();
-
-  /** Creates a new observable map using a [SplayTreeMap]. */
-  ObservableMap.sorted() : _map = new SplayTreeMap<K, V>();
-
-  /**
-   * Creates an observable map that contains all key value pairs of [other].
-   * It will attempt to use the same backing map type if the other map is a
-   * [LinkedHashMap], [SplayTreeMap], or [HashMap]. Otherwise it defaults to
-   * [HashMap].
-   *
-   * Note this will perform a shallow conversion. If you want a deep conversion
-   * you should use [toObservable].
-   */
-  factory ObservableMap.from(Map<K, V> other) {
-    var result = new ObservableMap<K, V>._createFromType(other);
-    other.forEach((K key, V value) { result[key] = value; });
-    return result;
-  }
-
-  factory ObservableMap._createFromType(Map<K, V> other) {
-    ObservableMap result;
-    if (other is SplayTreeMap) {
-      result = new ObservableMap<K, V>.sorted();
-    } else if (other is LinkedHashMap) {
-      result = new ObservableMap<K, V>.linked();
-    } else {
-      result = new ObservableMap<K, V>();
-    }
-    return result;
-  }
-
-  Iterable<K> get keys => _map.keys;
-
-  Iterable<V> get values => _map.values;
-
-  int get length =>_map.length;
-
-  bool get isEmpty => length == 0;
-
-  bool get isNotEmpty => !isEmpty;
-
-  bool containsValue(Object value) => _map.containsValue(value);
-
-  bool containsKey(Object key) => _map.containsKey(key);
-
-  V operator [](Object key) => _map[key];
-
-  void operator []=(K key, V value) {
-    int len = _map.length;
-    V oldValue = _map[key];
-    _map[key] = value;
-    if (hasObservers) {
-      if (len != _map.length) {
-        notifyPropertyChange(_LENGTH, len, _map.length);
-        notifyChange(new MapChangeRecord(key, isInsert: true));
-      } else if (!identical(oldValue, value)) {
-        notifyChange(new MapChangeRecord(key));
-      }
-    }
-  }
-
-  V putIfAbsent(K key, V ifAbsent()) {
-    int len = _map.length;
-    V result = _map.putIfAbsent(key, ifAbsent);
-    if (hasObservers && len != _map.length) {
-      notifyPropertyChange(_LENGTH, len, _map.length);
-      notifyChange(new MapChangeRecord(key, isInsert: true));
-    }
-    return result;
-  }
-
-  V remove(Object key) {
-    int len = _map.length;
-    V result =  _map.remove(key);
-    if (hasObservers && len != _map.length) {
-      notifyChange(new MapChangeRecord(key, isRemove: true));
-      notifyPropertyChange(_LENGTH, len, _map.length);
-    }
-    return result;
-  }
-
-  void clear() {
-    int len = _map.length;
-    if (hasObservers && len > 0) {
-      _map.forEach((key, value) {
-        notifyChange(new MapChangeRecord(key, isRemove: true));
-      });
-      notifyPropertyChange(_LENGTH, len, 0);
-    }
-    _map.clear();
-  }
-
-  void forEach(void f(K key, V value)) => _map.forEach(f);
-
-  String toString() => Maps.mapToString(this);
-}