content: // 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 dart2js.util;
  
  /**
   * The expensive map is a data structure useful for tracking down
   * excessive memory usage due to large maps. It acts as an ordinary
   * hash map, but it uses 10 times more memory (by default).
   */
  class ExpensiveMap<K, V> implements Map<K, V> {
  
    final List _maps;
  
    ExpensiveMap([int copies = 10]) : _maps = new List(copies) {
      assert(copies > 0);
      for (int i = 0; i < _maps.length; i++) {
        _maps[i] = new Map<K, V>();
      }
    }
  
    int get length => _maps[0].length;
    bool get isEmpty => _maps[0].isEmpty;
    bool get isNotEmpty => _maps[0].isNotEmpty;
  
    Iterable<K> get keys => _maps[0].keys;
    Iterable<V> get values => _maps[0].values;
  
    bool containsKey(K key) => _maps[0].containsKey(key);
    bool containsValue(V value) => _maps[0].containsValue(value);
  
    V operator[](K key) => _maps[0][key];
  
    void forEach(void action(K key, V value)) {
      _maps[0].forEach(action);
    }
  
    void operator[]=(K key, V value) {
      for (int i = 0; i < _maps.length; i++) {
        _maps[i][key] = value;
      }
    }
  
    V putIfAbsent(K key, V ifAbsent()) {
      if (containsKey(key)) return this[key];
      V value = ifAbsent();
      this[key] = value;
      return value;
    }
  
    void addAll(Map<K, V> other) {
      for (int i = 0; i < _maps.length; i++) {
        _maps[i].addAll(other);
      }
    }
  
    V remove(Object key) {
      V result = _maps[0].remove(key);
      for (int i = 1; i < _maps.length; i++) {
        _maps[i].remove(key);
      }
      return result;
    }
  
    void clear() {
      for (int i = 0; i < _maps.length; i++) {
        _maps[i].clear();
      }
    }
  
    String toString() => "expensive(${_maps[0]}x${_maps.length})";
  }
  