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| 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. |
| 4 |
| 5 // VM-internalized implementation of a default-constructed LinkedHashMap. |
| 6 // Currently calls the runtime for most operations. |
| 7 class _InternalLinkedHashMap<K, V> implements HashMap<K, V>, |
| 8 LinkedHashMap<K, V> { |
| 9 factory _InternalLinkedHashMap() native "LinkedHashMap_allocate"; |
| 10 int get length native "LinkedHashMap_getLength"; |
| 11 V operator [](K key) native "LinkedHashMap_lookUp"; |
| 12 void operator []=(K key, V value) native "LinkedHashMap_insertOrUpdate"; |
| 13 V remove(K key) native "LinkedHashMap_remove"; |
| 14 void clear() native "LinkedHashMap_clear"; |
| 15 bool containsKey(K key) native "LinkedHashMap_containsKey"; |
| 16 |
| 17 bool get isEmpty => length == 0; |
| 18 bool get isNotEmpty => !isEmpty; |
| 19 |
| 20 List _toArray() native "LinkedHashMap_toArray"; |
| 21 |
| 22 // "Modificaton marks" are tokens used to detect concurrent modification. |
| 23 // Considering only modifications (M) and iterator creation (I) events, e.g.: |
| 24 // M, M, M, I, I, M, I, M, M, I, I, I, M ... |
| 25 // a new mark is allocated at the start of each run of I's and cleared from |
| 26 // the map at the start of each run of M's. Iterators' moveNext check whether |
| 27 // the map's mark was changed or cleared since the iterator was created. |
| 28 // TODO(koda): Consider a counter instead. |
| 29 Object _getModMark(bool create) native "LinkedHashMap_getModMark"; |
| 30 |
| 31 void addAll(Map<K, V> other) { |
| 32 other.forEach((K key, V value) { |
| 33 this[key] = value; |
| 34 }); |
| 35 } |
| 36 |
| 37 V putIfAbsent(K key, Function ifAbsent) { |
| 38 if (containsKey(key)) { |
| 39 return this[key]; |
| 40 } else { |
| 41 V value = ifAbsent(); |
| 42 this[key] = value; |
| 43 return value; |
| 44 } |
| 45 } |
| 46 |
| 47 bool containsValue(V value) { |
| 48 for (V v in values) { |
| 49 if (v == value) { |
| 50 return true; |
| 51 } |
| 52 } |
| 53 return false; |
| 54 } |
| 55 |
| 56 void forEach(Function f) { |
| 57 for (K key in keys) { |
| 58 f(key, this[key]); |
| 59 } |
| 60 } |
| 61 |
| 62 // The even-indexed entries of toArray are the keys. |
| 63 Iterable<K> get keys => |
| 64 new _ListStepIterable<K>(this, _getModMark(true), _toArray(), -2, 2); |
| 65 |
| 66 // The odd-indexed entries of toArray are the values. |
| 67 Iterable<V> get values => |
| 68 new _ListStepIterable<V>(this, _getModMark(true), _toArray(), -1, 2); |
| 69 |
| 70 String toString() => Maps.mapToString(this); |
| 71 } |
| 72 |
| 73 // Iterates over a list from a given offset and step size. |
| 74 class _ListStepIterable<E> extends IterableBase<E> { |
| 75 _InternalLinkedHashMap _map; |
| 76 Object _modMark; |
| 77 List _list; |
| 78 int _offset; |
| 79 int _step; |
| 80 |
| 81 _ListStepIterable(this._map, this._modMark, |
| 82 this._list, this._offset, this._step); |
| 83 |
| 84 Iterator<E> get iterator => |
| 85 new _ListStepIterator(_map, _modMark, _list, _offset, _step); |
| 86 |
| 87 // TODO(koda): Should this check for concurrent modification? |
| 88 int get length => _map.length; |
| 89 bool get isEmpty => length == 0; |
| 90 bool get isNotEmpty => !isEmpty; |
| 91 } |
| 92 |
| 93 class _ListStepIterator<E> implements Iterator<E> { |
| 94 _InternalLinkedHashMap _map; |
| 95 Object _modMark; |
| 96 List _list; |
| 97 int _offset; |
| 98 int _step; |
| 99 |
| 100 _ListStepIterator(this._map, this._modMark, |
| 101 this._list, this._offset, this._step); |
| 102 |
| 103 bool moveNext() { |
| 104 if (_map._getModMark(false) != _modMark) { |
| 105 throw new ConcurrentModificationError(_map); |
| 106 } |
| 107 _offset += _step; |
| 108 return _offset < _list.length; |
| 109 } |
| 110 |
| 111 E get current { |
| 112 if (_offset < 0 || _offset >= _list.length) { |
| 113 return null; |
| 114 } |
| 115 return _list[_offset]; |
| 116 } |
| 117 } |
| 118 |
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