Index: packages/collection/lib/src/wrappers.dart |
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+// 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. |
+ |
+import "dart:collection"; |
+import "dart:math" as math; |
+ |
+import "typed_wrappers.dart"; |
+import "unmodifiable_wrappers.dart"; |
+ |
+typedef K _KeyForValue<K, V>(V value); |
+ |
+/// A base class for delegating iterables. |
+/// |
+/// Subclasses can provide a [_base] that should be delegated to. Unlike |
+/// [DelegatingIterable], this allows the base to be created on demand. |
+abstract class _DelegatingIterableBase<E> implements Iterable<E> { |
+ Iterable<E> get _base; |
+ |
+ const _DelegatingIterableBase(); |
+ |
+ bool any(bool test(E element)) => _base.any(test); |
+ |
+ bool contains(Object element) => _base.contains(element); |
+ |
+ E elementAt(int index) => _base.elementAt(index); |
+ |
+ bool every(bool test(E element)) => _base.every(test); |
+ |
+ Iterable<T> expand<T>(Iterable<T> f(E element)) => _base.expand(f); |
+ |
+ E get first => _base.first; |
+ |
+ E firstWhere(bool test(E element), {E orElse()}) => |
+ _base.firstWhere(test, orElse: orElse); |
+ |
+ T fold<T>(T initialValue, T combine(T previousValue, E element)) => |
+ _base.fold(initialValue, combine); |
+ |
+ void forEach(void f(E element)) => _base.forEach(f); |
+ |
+ bool get isEmpty => _base.isEmpty; |
+ |
+ bool get isNotEmpty => _base.isNotEmpty; |
+ |
+ Iterator<E> get iterator => _base.iterator; |
+ |
+ String join([String separator = ""]) => _base.join(separator); |
+ |
+ E get last => _base.last; |
+ |
+ E lastWhere(bool test(E element), {E orElse()}) => |
+ _base.lastWhere(test, orElse: orElse); |
+ |
+ int get length => _base.length; |
+ |
+ Iterable<T> map<T>(T f(E element)) => _base.map(f); |
+ |
+ E reduce(E combine(E value, E element)) => _base.reduce(combine); |
+ |
+ E get single => _base.single; |
+ |
+ E singleWhere(bool test(E element)) => _base.singleWhere(test); |
+ |
+ Iterable<E> skip(int n) => _base.skip(n); |
+ |
+ Iterable<E> skipWhile(bool test(E value)) => _base.skipWhile(test); |
+ |
+ Iterable<E> take(int n) => _base.take(n); |
+ |
+ Iterable<E> takeWhile(bool test(E value)) => _base.takeWhile(test); |
+ |
+ List<E> toList({bool growable: true}) => _base.toList(growable: growable); |
+ |
+ Set<E> toSet() => _base.toSet(); |
+ |
+ Iterable<E> where(bool test(E element)) => _base.where(test); |
+ |
+ String toString() => _base.toString(); |
+} |
+ |
+/// An [Iterable] that delegates all operations to a base iterable. |
+/// |
+/// This class can be used to hide non-`Iterable` methods of an iterable object, |
+/// or it can be extended to add extra functionality on top of an existing |
+/// iterable object. |
+class DelegatingIterable<E> extends _DelegatingIterableBase<E> { |
+ final Iterable<E> _base; |
+ |
+ /// Creates a wrapper that forwards operations to [base]. |
+ const DelegatingIterable(Iterable<E> base) : _base = base; |
+ |
+ /// Creates a wrapper that asserts the types of values in [base]. |
+ /// |
+ /// This soundly converts an [Iterable] without a generic type to an |
+ /// `Iterable<E>` by asserting that its elements are instances of `E` whenever |
+ /// they're accessed. If they're not, it throws a [CastError]. |
+ /// |
+ /// This forwards all operations to [base], so any changes in [base] will be |
+ /// reflected in [this]. If [base] is already an `Iterable<E>`, it's returned |
+ /// unmodified. |
+ static Iterable<E> typed<E>(Iterable base) => |
+ base is Iterable<E> ? base : new TypeSafeIterable<E>(base); |
+} |
+ |
+/// A [List] that delegates all operations to a base list. |
+/// |
+/// This class can be used to hide non-`List` methods of a list object, or it |
+/// can be extended to add extra functionality on top of an existing list |
+/// object. |
+class DelegatingList<E> extends DelegatingIterable<E> implements List<E> { |
+ const DelegatingList(List<E> base) : super(base); |
+ |
+ /// Creates a wrapper that asserts the types of values in [base]. |
+ /// |
+ /// This soundly converts a [List] without a generic type to a `List<E>` by |
+ /// asserting that its elements are instances of `E` whenever they're |
+ /// accessed. If they're not, it throws a [CastError]. Note that even if an |
+ /// operation throws a [CastError], it may still mutate the underlying |
+ /// collection. |
+ /// |
+ /// This forwards all operations to [base], so any changes in [base] will be |
+ /// reflected in [this]. If [base] is already a `List<E>`, it's returned |
+ /// unmodified. |
+ static List<E> typed<E>(List base) => |
+ base is List<E> ? base : new TypeSafeList<E>(base); |
+ |
+ List<E> get _listBase => _base; |
+ |
+ E operator [](int index) => _listBase[index]; |
+ |
+ void operator []=(int index, E value) { |
+ _listBase[index] = value; |
+ } |
+ |
+ void add(E value) { |
+ _listBase.add(value); |
+ } |
+ |
+ void addAll(Iterable<E> iterable) { |
+ _listBase.addAll(iterable); |
+ } |
+ |
+ Map<int, E> asMap() => _listBase.asMap(); |
+ |
+ void clear() { |
+ _listBase.clear(); |
+ } |
+ |
+ void fillRange(int start, int end, [E fillValue]) { |
+ _listBase.fillRange(start, end, fillValue); |
+ } |
+ |
+ Iterable<E> getRange(int start, int end) => _listBase.getRange(start, end); |
+ |
+ int indexOf(E element, [int start = 0]) => _listBase.indexOf(element, start); |
+ |
+ void insert(int index, E element) { |
+ _listBase.insert(index, element); |
+ } |
+ |
+ void insertAll(int index, Iterable<E> iterable) { |
+ _listBase.insertAll(index, iterable); |
+ } |
+ |
+ int lastIndexOf(E element, [int start]) => |
+ _listBase.lastIndexOf(element, start); |
+ |
+ void set length(int newLength) { |
+ _listBase.length = newLength; |
+ } |
+ |
+ bool remove(Object value) => _listBase.remove(value); |
+ |
+ E removeAt(int index) => _listBase.removeAt(index); |
+ |
+ E removeLast() => _listBase.removeLast(); |
+ |
+ void removeRange(int start, int end) { |
+ _listBase.removeRange(start, end); |
+ } |
+ |
+ void removeWhere(bool test(E element)) { |
+ _listBase.removeWhere(test); |
+ } |
+ |
+ void replaceRange(int start, int end, Iterable<E> iterable) { |
+ _listBase.replaceRange(start, end, iterable); |
+ } |
+ |
+ void retainWhere(bool test(E element)) { |
+ _listBase.retainWhere(test); |
+ } |
+ |
+ Iterable<E> get reversed => _listBase.reversed; |
+ |
+ void setAll(int index, Iterable<E> iterable) { |
+ _listBase.setAll(index, iterable); |
+ } |
+ |
+ void setRange(int start, int end, Iterable<E> iterable, [int skipCount = 0]) { |
+ _listBase.setRange(start, end, iterable, skipCount); |
+ } |
+ |
+ void shuffle([math.Random random]) { |
+ _listBase.shuffle(random); |
+ } |
+ |
+ void sort([int compare(E a, E b)]) { |
+ _listBase.sort(compare); |
+ } |
+ |
+ List<E> sublist(int start, [int end]) => _listBase.sublist(start, end); |
+} |
+ |
+/// A [Set] that delegates all operations to a base set. |
+/// |
+/// This class can be used to hide non-`Set` methods of a set object, or it can |
+/// be extended to add extra functionality on top of an existing set object. |
+class DelegatingSet<E> extends DelegatingIterable<E> implements Set<E> { |
+ const DelegatingSet(Set<E> base) : super(base); |
+ |
+ /// Creates a wrapper that asserts the types of values in [base]. |
+ /// |
+ /// This soundly converts a [Set] without a generic type to a `Set<E>` by |
+ /// asserting that its elements are instances of `E` whenever they're |
+ /// accessed. If they're not, it throws a [CastError]. Note that even if an |
+ /// operation throws a [CastError], it may still mutate the underlying |
+ /// collection. |
+ /// |
+ /// This forwards all operations to [base], so any changes in [base] will be |
+ /// reflected in [this]. If [base] is already a `Set<E>`, it's returned |
+ /// unmodified. |
+ static Set<E> typed<E>(Set base) => |
+ base is Set<E> ? base : new TypeSafeSet<E>(base); |
+ |
+ Set<E> get _setBase => _base; |
+ |
+ bool add(E value) => _setBase.add(value); |
+ |
+ void addAll(Iterable<E> elements) { |
+ _setBase.addAll(elements); |
+ } |
+ |
+ void clear() { |
+ _setBase.clear(); |
+ } |
+ |
+ bool containsAll(Iterable<Object> other) => _setBase.containsAll(other); |
+ |
+ Set<E> difference(Set<Object> other) => _setBase.difference(other); |
+ |
+ Set<E> intersection(Set<Object> other) => _setBase.intersection(other); |
+ |
+ E lookup(Object element) => _setBase.lookup(element); |
+ |
+ bool remove(Object value) => _setBase.remove(value); |
+ |
+ void removeAll(Iterable<Object> elements) { |
+ _setBase.removeAll(elements); |
+ } |
+ |
+ void removeWhere(bool test(E element)) { |
+ _setBase.removeWhere(test); |
+ } |
+ |
+ void retainAll(Iterable<Object> elements) { |
+ _setBase.retainAll(elements); |
+ } |
+ |
+ void retainWhere(bool test(E element)) { |
+ _setBase.retainWhere(test); |
+ } |
+ |
+ Set<E> union(Set<E> other) => _setBase.union(other); |
+ |
+ Set<E> toSet() => new DelegatingSet<E>(_setBase.toSet()); |
+} |
+ |
+/// A [Queue] that delegates all operations to a base queue. |
+/// |
+/// This class can be used to hide non-`Queue` methods of a queue object, or it |
+/// can be extended to add extra functionality on top of an existing queue |
+/// object. |
+class DelegatingQueue<E> extends DelegatingIterable<E> implements Queue<E> { |
+ const DelegatingQueue(Queue<E> queue) : super(queue); |
+ |
+ /// Creates a wrapper that asserts the types of values in [base]. |
+ /// |
+ /// This soundly converts a [Queue] without a generic type to a `Queue<E>` by |
+ /// asserting that its elements are instances of `E` whenever they're |
+ /// accessed. If they're not, it throws a [CastError]. Note that even if an |
+ /// operation throws a [CastError], it may still mutate the underlying |
+ /// collection. |
+ /// |
+ /// This forwards all operations to [base], so any changes in [base] will be |
+ /// reflected in [this]. If [base] is already a `Queue<E>`, it's returned |
+ /// unmodified. |
+ static Queue<E> typed<E>(Queue base) => |
+ base is Queue<E> ? base : new TypeSafeQueue<E>(base); |
+ |
+ Queue<E> get _baseQueue => _base; |
+ |
+ void add(E value) { |
+ _baseQueue.add(value); |
+ } |
+ |
+ void addAll(Iterable<E> iterable) { |
+ _baseQueue.addAll(iterable); |
+ } |
+ |
+ void addFirst(E value) { |
+ _baseQueue.addFirst(value); |
+ } |
+ |
+ void addLast(E value) { |
+ _baseQueue.addLast(value); |
+ } |
+ |
+ void clear() { |
+ _baseQueue.clear(); |
+ } |
+ |
+ bool remove(Object object) => _baseQueue.remove(object); |
+ |
+ void removeWhere(bool test(E element)) { |
+ _baseQueue.removeWhere(test); |
+ } |
+ |
+ void retainWhere(bool test(E element)) { |
+ _baseQueue.retainWhere(test); |
+ } |
+ |
+ E removeFirst() => _baseQueue.removeFirst(); |
+ |
+ E removeLast() => _baseQueue.removeLast(); |
+} |
+ |
+/// A [Map] that delegates all operations to a base map. |
+/// |
+/// This class can be used to hide non-`Map` methods of an object that extends |
+/// `Map`, or it can be extended to add extra functionality on top of an |
+/// existing map object. |
+class DelegatingMap<K, V> implements Map<K, V> { |
+ final Map<K, V> _base; |
+ |
+ const DelegatingMap(Map<K, V> base) : _base = base; |
+ |
+ /// Creates a wrapper that asserts the types of keys and values in [base]. |
+ /// |
+ /// This soundly converts a [Map] without generic types to a `Map<K, V>` by |
+ /// asserting that its keys are instances of `E` and its values are instances |
+ /// of `V` whenever they're accessed. If they're not, it throws a [CastError]. |
+ /// Note that even if an operation throws a [CastError], it may still mutate |
+ /// the underlying collection. |
+ /// |
+ /// This forwards all operations to [base], so any changes in [base] will be |
+ /// reflected in [this]. If [base] is already a `Map<K, V>`, it's returned |
+ /// unmodified. |
+ static Map<K, V> typed<K, V>(Map base) => |
+ base is Map<K, V> ? base : new TypeSafeMap<K, V>(base); |
+ |
+ V operator [](Object key) => _base[key]; |
+ |
+ void operator []=(K key, V value) { |
+ _base[key] = value; |
+ } |
+ |
+ void addAll(Map<K, V> other) { |
+ _base.addAll(other); |
+ } |
+ |
+ void clear() { |
+ _base.clear(); |
+ } |
+ |
+ bool containsKey(Object key) => _base.containsKey(key); |
+ |
+ bool containsValue(Object value) => _base.containsValue(value); |
+ |
+ void forEach(void f(K key, V value)) { |
+ _base.forEach(f); |
+ } |
+ |
+ bool get isEmpty => _base.isEmpty; |
+ |
+ bool get isNotEmpty => _base.isNotEmpty; |
+ |
+ Iterable<K> get keys => _base.keys; |
+ |
+ int get length => _base.length; |
+ |
+ V putIfAbsent(K key, V ifAbsent()) => _base.putIfAbsent(key, ifAbsent); |
+ |
+ V remove(Object key) => _base.remove(key); |
+ |
+ Iterable<V> get values => _base.values; |
+ |
+ String toString() => _base.toString(); |
+} |
+ |
+/// An unmodifiable [Set] view of the keys of a [Map]. |
+/// |
+/// The set delegates all operations to the underlying map. |
+/// |
+/// A `Map` can only contain each key once, so its keys can always |
+/// be viewed as a `Set` without any loss, even if the [Map.keys] |
+/// getter only shows an [Iterable] view of the keys. |
+/// |
+/// Note that [lookup] is not supported for this set. |
+class MapKeySet<E> extends _DelegatingIterableBase<E> |
+ with UnmodifiableSetMixin<E> { |
+ final Map<E, dynamic> _baseMap; |
+ |
+ MapKeySet(Map<E, dynamic> base) : _baseMap = base; |
+ |
+ Iterable<E> get _base => _baseMap.keys; |
+ |
+ bool contains(Object element) => _baseMap.containsKey(element); |
+ |
+ bool get isEmpty => _baseMap.isEmpty; |
+ |
+ bool get isNotEmpty => _baseMap.isNotEmpty; |
+ |
+ int get length => _baseMap.length; |
+ |
+ String toString() => "{${_base.join(', ')}}"; |
+ |
+ bool containsAll(Iterable<Object> other) => other.every(contains); |
+ |
+ /// Returns a new set with the the elements of [this] that are not in [other]. |
+ /// |
+ /// That is, the returned set contains all the elements of this [Set] that are |
+ /// not elements of [other] according to `other.contains`. |
+ /// |
+ /// Note that the returned set will use the default equality operation, which |
+ /// may be different than the equality operation [this] uses. |
+ Set<E> difference(Set<Object> other) => |
+ where((element) => !other.contains(element)).toSet(); |
+ |
+ /// Returns a new set which is the intersection between [this] and [other]. |
+ /// |
+ /// That is, the returned set contains all the elements of this [Set] that are |
+ /// also elements of [other] according to `other.contains`. |
+ /// |
+ /// Note that the returned set will use the default equality operation, which |
+ /// may be different than the equality operation [this] uses. |
+ Set<E> intersection(Set<Object> other) => where(other.contains).toSet(); |
+ |
+ /// Throws an [UnsupportedError] since there's no corresponding method for |
+ /// [Map]s. |
+ E lookup(Object element) => |
+ throw new UnsupportedError("MapKeySet doesn't support lookup()."); |
+ |
+ /// Returns a new set which contains all the elements of [this] and [other]. |
+ /// |
+ /// That is, the returned set contains all the elements of this [Set] and all |
+ /// the elements of [other]. |
+ /// |
+ /// Note that the returned set will use the default equality operation, which |
+ /// may be different than the equality operation [this] uses. |
+ Set<E> union(Set<E> other) => toSet()..addAll(other); |
+} |
+ |
+/// Creates a modifiable [Set] view of the values of a [Map]. |
+/// |
+/// The `Set` view assumes that the keys of the `Map` can be uniquely determined |
+/// from the values. The `keyForValue` function passed to the constructor finds |
+/// the key for a single value. The `keyForValue` function should be consistent |
+/// with equality. If `value1 == value2` then `keyForValue(value1)` and |
+/// `keyForValue(value2)` should be considered equal keys by the underlying map, |
+/// and vice versa. |
+/// |
+/// Modifying the set will modify the underlying map based on the key returned |
+/// by `keyForValue`. |
+/// |
+/// If the `Map` contents are not compatible with the `keyForValue` function, |
+/// the set will not work consistently, and may give meaningless responses or do |
+/// inconsistent updates. |
+/// |
+/// This set can, for example, be used on a map from database record IDs to the |
+/// records. It exposes the records as a set, and allows for writing both |
+/// `recordSet.add(databaseRecord)` and `recordMap[id]`. |
+/// |
+/// Effectively, the map will act as a kind of index for the set. |
+class MapValueSet<K, V> extends _DelegatingIterableBase<V> implements Set<V> { |
+ final Map<K, V> _baseMap; |
+ final _KeyForValue<K, V> _keyForValue; |
+ |
+ /// Creates a new [MapValueSet] based on [base]. |
+ /// |
+ /// [keyForValue] returns the key in the map that should be associated with |
+ /// the given value. The set's notion of equality is identical to the equality |
+ /// of the return values of [keyForValue]. |
+ MapValueSet(Map<K, V> base, K keyForValue(V value)) |
+ : _baseMap = base, |
+ _keyForValue = keyForValue; |
+ |
+ Iterable<V> get _base => _baseMap.values; |
+ |
+ bool contains(Object element) { |
+ if (element != null && element is! V) return false; |
+ var key = _keyForValue(element as V); |
+ |
+ return _baseMap.containsKey(key); |
+ } |
+ |
+ bool get isEmpty => _baseMap.isEmpty; |
+ |
+ bool get isNotEmpty => _baseMap.isNotEmpty; |
+ |
+ int get length => _baseMap.length; |
+ |
+ String toString() => toSet().toString(); |
+ |
+ bool add(V value) { |
+ K key = _keyForValue(value); |
+ bool result = false; |
+ _baseMap.putIfAbsent(key, () { |
+ result = true; |
+ return value; |
+ }); |
+ return result; |
+ } |
+ |
+ void addAll(Iterable<V> elements) => elements.forEach(add); |
+ |
+ void clear() => _baseMap.clear(); |
+ |
+ bool containsAll(Iterable<Object> other) => other.every(contains); |
+ |
+ /// Returns a new set with the the elements of [this] that are not in [other]. |
+ /// |
+ /// That is, the returned set contains all the elements of this [Set] that are |
+ /// not elements of [other] according to `other.contains`. |
+ /// |
+ /// Note that the returned set will use the default equality operation, which |
+ /// may be different than the equality operation [this] uses. |
+ Set<V> difference(Set<Object> other) => |
+ where((element) => !other.contains(element)).toSet(); |
+ |
+ /// Returns a new set which is the intersection between [this] and [other]. |
+ /// |
+ /// That is, the returned set contains all the elements of this [Set] that are |
+ /// also elements of [other] according to `other.contains`. |
+ /// |
+ /// Note that the returned set will use the default equality operation, which |
+ /// may be different than the equality operation [this] uses. |
+ Set<V> intersection(Set<Object> other) => where(other.contains).toSet(); |
+ |
+ V lookup(Object element) { |
+ if (element != null && element is! V) return null; |
+ var key = _keyForValue(element as V); |
+ |
+ return _baseMap[key]; |
+ } |
+ |
+ bool remove(Object element) { |
+ if (element != null && element is! V) return false; |
+ var key = _keyForValue(element as V); |
+ |
+ if (!_baseMap.containsKey(key)) return false; |
+ _baseMap.remove(key); |
+ return true; |
+ } |
+ |
+ void removeAll(Iterable<Object> elements) => elements.forEach(remove); |
+ |
+ void removeWhere(bool test(V element)) { |
+ var toRemove = []; |
+ _baseMap.forEach((key, value) { |
+ if (test(value)) toRemove.add(key); |
+ }); |
+ toRemove.forEach(_baseMap.remove); |
+ } |
+ |
+ void retainAll(Iterable<Object> elements) { |
+ var valuesToRetain = new Set<V>.identity(); |
+ for (var element in elements) { |
+ if (element != null && element is! V) continue; |
+ var key = _keyForValue(element as V); |
+ |
+ if (!_baseMap.containsKey(key)) continue; |
+ valuesToRetain.add(_baseMap[key]); |
+ } |
+ |
+ var keysToRemove = []; |
+ _baseMap.forEach((k, v) { |
+ if (!valuesToRetain.contains(v)) keysToRemove.add(k); |
+ }); |
+ keysToRemove.forEach(_baseMap.remove); |
+ } |
+ |
+ void retainWhere(bool test(V element)) => |
+ removeWhere((element) => !test(element)); |
+ |
+ /// Returns a new set which contains all the elements of [this] and [other]. |
+ /// |
+ /// That is, the returned set contains all the elements of this [Set] and all |
+ /// the elements of [other]. |
+ /// |
+ /// Note that the returned set will use the default equality operation, which |
+ /// may be different than the equality operation [this] uses. |
+ Set<V> union(Set<V> other) => toSet()..addAll(other); |
+} |