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pkg/dev_compiler/tool/input_sdk/lib/collection/maps.dart

-// Copyright (c) 2012, 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 dart.collection;
-
-/**
- * Base class for implementing a [Map].
- *
- * This class has a basic implementation of all but five of the members of
- * [Map].
- * A basic `Map` class can be implemented by extending this class and
- * implementing `keys`, `operator[]`, `operator[]=`, `remove` and `clear`.
- * The remaining operations are implemented in terms of these five.
- *
- * The `keys` iterable should have efficient [length] and [contains]
- * operations, and it should catch concurrent modifications of the keys
- * while iterating.
- *
- * A more efficient implementation is usually possible by overriding
- * some of the other members as well.
- */
-abstract class MapBase<K, V> = Object with MapMixin<K, V>;
-
-
-/**
- * Mixin implementing a [Map].
- *
- * This mixin has a basic implementation of all but five of the members of
- * [Map].
- * A basic `Map` class can be implemented by mixin in this class and
- * implementing `keys`, `operator[]`, `operator[]=`, `remove` and `clear`.
- * The remaining operations are implemented in terms of these five.
- *
- * The `keys` iterable should have efficient [length] and [contains]
- * operations, and it should catch concurrent modifications of the keys
- * while iterating.
- *
- * A more efficient implementation is usually possible by overriding
- * some of the other members as well.
- */
-abstract class MapMixin<K, V> implements Map<K, V> {
-  Iterable<K> get keys;
-  V operator[](Object key);
-  operator []=(K key, V value);
-  V remove(Object key);
-  // The `clear` operation should not be based on `remove`.
-  // It should clear the map even if some keys are not equal to themselves.
-  void clear();
-
-  void forEach(void action(K key, V value)) {
-    for (K key in keys) {
-      action(key, this[key]);
-    }
-  }
-
-  void addAll(Map<K, V> other) {
-    for (K key in other.keys) {
-      this[key] = other[key];
-    }
-  }
-
-  bool containsValue(Object value) {
-    for (K key in keys) {
-      if (this[key] == value) return true;
-    }
-    return false;
-  }
-
-  V putIfAbsent(K key, V ifAbsent()) {
-    if (containsKey(key)) {
-      return this[key];
-    }
-    return this[key] = ifAbsent();
-  }
-
-  bool containsKey(Object key) => keys.contains(key);
-  int get length => keys.length;
-  bool get isEmpty => keys.isEmpty;
-  bool get isNotEmpty => keys.isNotEmpty;
-  Iterable<V> get values => new _MapBaseValueIterable<K, V>(this);
-  String toString() => Maps.mapToString(this);
-}
-
-/**
- * Basic implementation of an unmodifiable [Map].
- *
- * This class has a basic implementation of all but two of the members of
- * an umodifiable [Map].
- * A simple unmodifiable `Map` class can be implemented by extending this
- * class and implementing `keys` and `operator[]`.
- *
- * Modifying operations throw when used.
- * The remaining non-modifying operations are implemented in terms of `keys`
- * and `operator[]`.
- *
- * The `keys` iterable should have efficient [length] and [contains]
- * operations, and it should catch concurrent modifications of the keys
- * while iterating.
- *
- * A more efficient implementation is usually possible by overriding
- * some of the other members as well.
- */
-abstract class UnmodifiableMapBase<K, V> =
-    MapBase<K, V> with _UnmodifiableMapMixin<K, V>;
-
-/**
- * Implementation of [Map.values] based on the map and its [Map.keys] iterable.
- *
- * Iterable that iterates over the values of a `Map`.
- * It accesses the values by iterating over the keys of the map, and using the
- * map's `operator[]` to lookup the keys.
- */
-class _MapBaseValueIterable<K, V> extends Iterable<V>
-                                  implements EfficientLength {
-  final Map<K, V> _map;
-  _MapBaseValueIterable(this._map);
-
-  int get length => _map.length;
-  bool get isEmpty => _map.isEmpty;
-  bool get isNotEmpty => _map.isNotEmpty;
-  V get first => _map[_map.keys.first];
-  V get single => _map[_map.keys.single];
-  V get last => _map[_map.keys.last];
-
-  Iterator<V> get iterator => new _MapBaseValueIterator<K, V>(_map);
-}
-
-/**
- * Iterator created by [_MapBaseValueIterable].
- *
- * Iterates over the values of a map by iterating its keys and lookup up the
- * values.
- */
-class _MapBaseValueIterator<K, V> implements Iterator<V> {
-  final Iterator<K> _keys;
-  final Map<K, V> _map;
-  V _current = null;
-
-  _MapBaseValueIterator(Map<K, V> map)
-      : _map = map,
-        _keys = map.keys.iterator;
-
-  bool moveNext() {
-    if (_keys.moveNext()) {
-      _current = _map[_keys.current];
-      return true;
-    }
-    _current = null;
-    return false;
-  }
-
-  V get current => _current;
-}
-
-/**
- * Mixin that overrides mutating map operations with implementations that throw.
- */
-abstract class _UnmodifiableMapMixin<K, V> implements Map<K, V> {
-  void operator[]=(K key, V value) {
-    throw new UnsupportedError("Cannot modify unmodifiable map");
-  }
-  void addAll(Map<K, V> other) {
-    throw new UnsupportedError("Cannot modify unmodifiable map");
-  }
-  void clear() {
-    throw new UnsupportedError("Cannot modify unmodifiable map");
-  }
-  V remove(Object key) {
-    throw new UnsupportedError("Cannot modify unmodifiable map");
-  }
-  V putIfAbsent(K key, V ifAbsent()) {
-    throw new UnsupportedError("Cannot modify unmodifiable map");
-  }
-}
-
-/**
- * Wrapper around a class that implements [Map] that only exposes `Map` members.
- *
- * A simple wrapper that delegates all `Map` members to the map provided in the
- * constructor.
- *
- * Base for delegating map implementations like [UnmodifiableMapView].
- */
-class MapView<K, V> implements Map<K, V> {
-  final Map<K, V> _map;
-  const MapView(Map<K, V> map) : _map = map;
-
-  V operator[](Object key) => _map[key];
-  void operator[]=(K key, V value) { _map[key] = value; }
-  void addAll(Map<K, V> other) { _map.addAll(other); }
-  void clear() { _map.clear(); }
-  V putIfAbsent(K key, V ifAbsent()) => _map.putIfAbsent(key, ifAbsent);
-  bool containsKey(Object key) => _map.containsKey(key);
-  bool containsValue(Object value) => _map.containsValue(value);
-  void forEach(void action(K key, V value)) { _map.forEach(action); }
-  bool get isEmpty => _map.isEmpty;
-  bool get isNotEmpty => _map.isNotEmpty;
-  int get length => _map.length;
-  Iterable<K> get keys => _map.keys;
-  V remove(Object key) => _map.remove(key);
-  String toString() => _map.toString();
-  Iterable<V> get values => _map.values;
-}
-
-/**
- * View of a [Map] that disallow modifying the map.
- *
- * A wrapper around a `Map` that forwards all members to the map provided in
- * the constructor, except for operations that modify the map.
- * Modifying operations throw instead.
- */
-class UnmodifiableMapView<K, V> =
-    MapView<K, V> with _UnmodifiableMapMixin<K, V>;
-
-/**
- * Helper class which implements complex [Map] operations
- * in term of basic ones ([Map.keys], [Map.operator []],
- * [Map.operator []=] and [Map.remove].)  Not all methods are
- * necessary to implement each particular operation.
- */
-class Maps {
-  static bool containsValue(Map map, Object value) {
-    for (final v in map.values) {
-      if (v == value) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  static bool containsKey(Map map, Object key) {
-    for (final k in map.keys) {
-      if (k == key) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  static putIfAbsent(Map map, key, ifAbsent()) {
-    if (map.containsKey(key)) {
-      return map[key];
-    }
-    final v = ifAbsent();
-    map[key] = v;
-    return v;
-  }
-
-  static clear(Map map) {
-    for (final k in map.keys.toList()) {
-      map.remove(k);
-    }
-  }
-
-  static forEach(Map map, void f(key, value)) {
-    for (final k in map.keys) {
-      f(k, map[k]);
-    }
-  }
-
-  static Iterable getValues(Map map) {
-    return map.keys.map((key) => map[key]);
-  }
-
-  static int length(Map map) => map.keys.length;
-
-  static bool isEmpty(Map map) => map.keys.isEmpty;
-
-  static bool isNotEmpty(Map map) => map.keys.isNotEmpty;
-
-  /**
-   * Returns a string representing the specified map. The returned string
-   * looks like this: [:'{key0: value0, key1: value1, ... keyN: valueN}':].
-   * The value returned by its [toString] method is used to represent each
-   * key or value.
-   *
-   * If the map collection contains a reference to itself, either
-   * directly as a key or value, or indirectly through other collections
-   * or maps, the contained reference is rendered as [:'{...}':]. This
-   * prevents the infinite regress that would otherwise occur. So, for example,
-   * calling this method on a map whose sole entry maps the string key 'me'
-   * to a reference to the map would return [:'{me: {...}}':].
-   *
-   * A typical implementation of a map's [toString] method will
-   * simply return the results of this method applied to the collection.
-   */
-  static String mapToString(Map m) {
-    // Reuse the list in IterableBase for detecting toString cycles.
-    if (_isToStringVisiting(m)) { return '{...}'; }
-
-    var result = new StringBuffer();
-    try {
-      _toStringVisiting.add(m);
-      result.write('{');
-      bool first = true;
-      m.forEach((k, v) {
-        if(!first) {
-          result.write(', ');
-        }
-        first = false;
-        result.write(k);
-        result.write(': ');
-        result.write(v);
-      });
-      result.write('}');
-    } finally {
-      assert(identical(_toStringVisiting.last, m));
-      _toStringVisiting.removeLast();
-    }
-
-    return result.toString();
-  }
-
-  static _id(x) => x;
-
-  /**
-   * Fills a map with key/value pairs computed from [iterable].
-   *
-   * This method is used by Map classes in the named constructor fromIterable.
-   */
-  static void _fillMapWithMappedIterable(Map map, Iterable iterable,
-                                         key(element), value(element)) {
-    if (key == null) key = _id;
-    if (value == null) value = _id;
-
-    for (var element in iterable) {
-      map[key(element)] = value(element);
-    }
-  }
-
-  /**
-   * Fills a map by associating the [keys] to [values].
-   *
-   * This method is used by Map classes in the named constructor fromIterables.
-   */
-  static void _fillMapWithIterables(Map map, Iterable keys,
-                                    Iterable values) {
-    Iterator keyIterator = keys.iterator;
-    Iterator valueIterator = values.iterator;
-
-    bool hasNextKey = keyIterator.moveNext();
-    bool hasNextValue = valueIterator.moveNext();
-
-    while (hasNextKey && hasNextValue) {
-      map[keyIterator.current] = valueIterator.current;
-      hasNextKey = keyIterator.moveNext();
-      hasNextValue = valueIterator.moveNext();
-    }
-
-    if (hasNextKey || hasNextValue) {
-      throw new ArgumentError("Iterables do not have same length.");
-    }
-  }
-}