Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/collection/src/unmodifiable_wrappers.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.
+
+/**
+ * Wrappers that prevent a List, Set, or Map object from being modified.
+ *
+ * The [Set] and [Map] wrappers allow reading from the wrapped collection,
+ * but prohibit writing.
+ *
+ * The [List] wrapper prevents changes to the length of the wrapped list,
+ * but allows changes to the contents.
+ */
+part of dart.pkg.collection.wrappers;
+
+/**
+ * A fixed-length list.
+ *
+ * A `NonGrowableListView` contains a [List] object and ensures that
+ * its length does not change.
+ * Methods that would change the length of the list,
+ * such as [add] and [remove], throw an [UnsupportedError].
+ * All other methods work directly on the underlying list.
+ *
+ * This class _does_ allow changes to the contents of the wrapped list.
+ * You can, for example, [sort] the list.
+ * Permitted operations defer to the wrapped list.
+ */
+class NonGrowableListView<E> extends DelegatingList<E>
+                             with NonGrowableListMixin<E> {
+  NonGrowableListView(List<E> listBase) : super(listBase);
+}
+
+/**
+ * Mixin class that implements a throwing version of all list operations that
+ * change the List's length.
+ */
+abstract class NonGrowableListMixin<E> implements List<E> {
+  static _throw() {
+    throw new UnsupportedError(
+        "Cannot change the length of a fixed-length list");
+  }
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  void set length(int newLength) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  bool add(E value) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  void addAll(Iterable<E> iterable) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  void insert(int index, E element) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  void insertAll(int index, Iterable<E> iterable) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  bool remove(Object value) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  E removeAt(int index) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  E removeLast() => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  void removeWhere(bool test(E element)) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  void retainWhere(bool test(E element)) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  void removeRange(int start, int end) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  void replaceRange(int start, int end, Iterable<E> iterable) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the length of the list are disallowed.
+   */
+  void clear() => _throw();
+}
+
+/**
+ * An unmodifiable set.
+ *
+ * An UnmodifiableSetView contains a [Set] object and ensures
+ * that it does not change.
+ * Methods that would change the set,
+ * such as [add] and [remove], throw an [UnsupportedError].
+ * Permitted operations defer to the wrapped set.
+ */
+class UnmodifiableSetView<E> extends DelegatingSet<E>
+                             with UnmodifiableSetMixin<E> {
+  UnmodifiableSetView(Set<E> setBase) : super(setBase);
+}
+
+/**
+ * Mixin class that implements a throwing version of all set operations that
+ * change the Set.
+ */
+abstract class UnmodifiableSetMixin<E> implements Set<E> {
+  _throw() {
+    throw new UnsupportedError("Cannot modify an unmodifiable Set");
+  }
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the set are disallowed.
+   */
+  bool add(E value) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the set are disallowed.
+   */
+  void addAll(Iterable<E> elements) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the set are disallowed.
+   */
+  bool remove(Object value) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the set are disallowed.
+   */
+  void removeAll(Iterable elements) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the set are disallowed.
+   */
+  void retainAll(Iterable elements) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the set are disallowed.
+   */
+  void removeWhere(bool test(E element)) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the set are disallowed.
+   */
+  void retainWhere(bool test(E element)) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the set are disallowed.
+   */
+  void clear() => _throw();
+}
+
+/**
+ * An unmodifiable map.
+ *
+ * An UnmodifiableMapView contains a [Map] object and ensures
+ * that it does not change.
+ * Methods that would change the map,
+ * such as [addAll] and [remove], throw an [UnsupportedError].
+ * Permitted operations defer to the wrapped map.
+ */
+class UnmodifiableMapView<K, V> extends DelegatingMap<K, V>
+                                with UnmodifiableMapMixin<K, V> {
+  UnmodifiableMapView(Map<K, V> baseMap) : super(baseMap);
+}
+
+/**
+ * Mixin class that implements a throwing version of all map operations that
+ * change the Map.
+ */
+abstract class UnmodifiableMapMixin<K, V> implements Map<K, V> {
+  static _throw() {
+    throw new UnsupportedError("Cannot modify an unmodifiable Map");
+  }
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the map are disallowed.
+   */
+  void operator []=(K key, V value) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the map are disallowed.
+   */
+  V putIfAbsent(K key, V ifAbsent()) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the map are disallowed.
+   */
+  void addAll(Map<K, V> other) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the map are disallowed.
+   */
+  V remove(K key) => _throw();
+
+  /**
+   * Throws an [UnsupportedError];
+   * operations that change the map are disallowed.
+   */
+  void clear() => _throw();
+}