Make dart:collection strong-mode clean.

sdk/lib/collection/queue.dart

 // Copyright (c) 2011, 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;
 
 /**
  * A [Queue] is a collection that can be manipulated at both ends. One
  * can iterate over the elements of a queue through [forEach] or with
  * an [Iterator].
@@ skipping 78 matching lines @@
    */
   void retainWhere(bool test(E element));
 
   /**
    * Removes all elements in the queue. The size of the queue becomes zero.
    */
   void clear();
 }
 
 
-class _DoubleLink {
-  _DoubleLink _previousLink;
-  _DoubleLink _nextLink;
+class _DoubleLink<E extends _DoubleLink> {
+  E _previousLink;
+  E _nextLink;
 
-  void _link(_DoubleLink previous,
-             _DoubleLink next) {
+  void _link(E previous, E next) {
     _nextLink = next;
     _previousLink = previous;
     if (previous != null) previous._nextLink = this;
     if (next != null) next._previousLink = this;
   }
 
   void _unlink() {
     if (_previousLink != null) _previousLink._nextLink = _nextLink;
     if (_nextLink != null) _nextLink._previousLink = _previousLink;
     _nextLink = null;
     _previousLink = null;
   }
 }
 
 /**
  * An entry in a doubly linked list. It contains a pointer to the next
  * entry, the previous entry, and the boxed element.
  */
-class DoubleLinkedQueueEntry<E> extends _DoubleLink {
+abstract class DoubleLinkedQueueEntry<E> {
+  factory DoubleLinkedQueueEntry(E element) = _UserDoubleLinkedQueueEntry<E>;

[Lasse Reichstein Nielsen, 2016/05/13 05:31:09]

This changes a generative constructor to a factory constructor.
If any class extends DoubleLinkedQueueEntry, it will stop working.

(I guess this is another lesson in separating interface and implementation :)

[floitsch, 2016/05/13 17:12:01]

Fixed in https://codereview.chromium.org/1973903005

+
+  /// The element in the queue.
+  E get element;
+
+  /// Appends the given [e] as entry just after this entry.
+  void append(E e);
+
+  /// Prepends the given [e] as entry just before this entry.
+  void prepend(E e);
+
+  /// Returns the previous entry or `null` if there is none.
+  DoubleLinkedQueueEntry<E> previousEntry();
+
+  /// Returns the next entry or `null` if there is none.
+  DoubleLinkedQueueEntry<E> nextEntry();
+}

[sra1, 2016/05/13 03:00:13]

This is a breaking change since DoubleLinkedQueueEntry no longer has a remove()
method.

There are a bunch of additional warnings when compiling swarm due to this
change.

[floitsch, 2016/05/13 17:12:01]

Argh. Missed the 'remove' function.
Fixing in https://codereview.chromium.org/1973903005

+
+/// Default implementation of a doubly linked queue entry.
+///
+/// This implementation is only used if a user instantiates a
+/// [DoubleLinkedQueueEntry] directly. The internal implementations don't use
+/// this class.
+class _UserDoubleLinkedQueueEntry<E>
+    extends _DoubleLink<_UserDoubleLinkedQueueEntry<E>>
+    implements DoubleLinkedQueueEntry<E> {
   E element;
 
-  DoubleLinkedQueueEntry(this.element);
+  _UserDoubleLinkedQueueEntry(this.element);
 
   void append(E e) {
-    new DoubleLinkedQueueEntry<E>(e)._link(this, _nextLink);
+    new _UserDoubleLinkedQueueEntry<E>(e)._link(this, _nextLink);
   }
 
   void prepend(E e) {
-    new DoubleLinkedQueueEntry<E>(e)._link(_previousLink, this);
+    new _UserDoubleLinkedQueueEntry<E>(e)._link(_previousLink, this);
   }
 
   E remove() {
     _unlink();
     return element;
   }
 
-  DoubleLinkedQueueEntry<E> previousEntry() {
-    return _previousLink;
-  }
+  DoubleLinkedQueueEntry<E> previousEntry() => _previousLink;
 
-  DoubleLinkedQueueEntry<E> nextEntry() {
-    return _nextLink;
-  }
+  DoubleLinkedQueueEntry<E> nextEntry() => _nextLink;
 }
 
 /**
  * Interface for the link classes used by [DoubleLinkedQueue].
  *
  * Both the [_DoubleLinkedQueueElement] and [_DoubleLinkedQueueSentinel]
- * implements this interface.
+ * implement this interface.
  * The entry contains a link back to the queue, so calling `append`
  * or `prepend` can correctly update the element count.
  */
-abstract class _DoubleLinkedQueueEntry<E> extends _DoubleLink {
+abstract class _DoubleLinkedQueueEntry<E>
+    extends _DoubleLink<_DoubleLinkedQueueEntry<E>> {
   DoubleLinkedQueue<E> _queue;
   _DoubleLinkedQueueEntry(this._queue);
 
-  _DoubleLinkedQueueElement _asNonSentinelEntry();
+  DoubleLinkedQueueEntry<E> _asNonSentinelEntry();
 
   void _append(E e) {
     new _DoubleLinkedQueueElement<E>(e, _queue)._link(this, _nextLink);
   }
 
   void _prepend(E e) {
     new _DoubleLinkedQueueElement<E>(e, _queue)._link(_previousLink, this);
   }
 
   E _remove();
 
   E get element;
 
   DoubleLinkedQueueEntry<E> nextEntry() {
-    _DoubleLinkedQueueEntry next = _nextLink;
-    return next._asNonSentinelEntry();
+    return _nextLink._asNonSentinelEntry();
   }
 
   DoubleLinkedQueueEntry<E> previousEntry() {
-    _DoubleLinkedQueueEntry previous = _previousLink;
-    return previous._asNonSentinelEntry();
+    return _previousLink._asNonSentinelEntry();
   }
 }
 
 /**
  * The actual entry type used by the [DoubleLinkedQueue].
  *
  * The entry contains a reference to the queue, allowing
  * [append]/[prepend] to update the list length.
  */
 class _DoubleLinkedQueueElement<E> extends _DoubleLinkedQueueEntry<E>
@@ skipping 16 matching lines @@
     _queue = null;
     _unlink();
     return element;
   }
 
   E remove() {
     if (_queue != null) _queue._elementCount--;
     return _remove();
   }
 
-  _DoubleLinkedQueueElement _asNonSentinelEntry() {
+  _DoubleLinkedQueueElement<E> _asNonSentinelEntry() {
     return this;
   }
 }
 
 /**
  * A sentinel in a double linked list is used to manipulate the list
  * at both ends.
  * A double linked list has exactly one sentinel,
  * which is the only entry when the list is constructed.
  * Initially, a sentinel has its next and previous entry point to itself.
  * A sentinel does not box any user element.
  */
 class _DoubleLinkedQueueSentinel<E> extends _DoubleLinkedQueueEntry<E> {
-  _DoubleLinkedQueueSentinel(DoubleLinkedQueue queue) : super(queue) {
+  _DoubleLinkedQueueSentinel(DoubleLinkedQueue<E> queue) : super(queue) {
     _previousLink = this;
     _nextLink = this;
   }
 
-  _DoubleLinkedQueueElement _asNonSentinelEntry() {
+  DoubleLinkedQueueEntry<E> _asNonSentinelEntry() {
     return null;
   }
 
   /** Hit by, e.g., [DoubleLinkedQueue.removeFirst] if the queue is empty. */
   E _remove() {
     throw IterableElementError.noElement();
   }
 
   /** Hit by, e.g., [DoubleLinkedQueue.first] if the queue is empty. */
   E get element {
@@ skipping 15 matching lines @@
   }
 
   /**
    * Creates a double-linked queue containing all [elements].
    *
    * The element order in the queue is as if the elements were added using
    * [addLast] in the order provided by [elements.iterator].
    */
   factory DoubleLinkedQueue.from(Iterable elements) {
     Queue<E> list = new DoubleLinkedQueue<E>();
-    for (final E e in elements) {
-      list.addLast(e);
+    for (final e in elements) {
+      E element = e as Object/*=E*/;
+      list.addLast(element);
     }
     return list;
   }
 
   int get length => _elementCount;
 
   void addLast(E value) {
     _sentinel._prepend(value);
     _elementCount++;
   }
 
   void addFirst(E value) {
     _sentinel._append(value);
     _elementCount++;
   }
 
   void add(E value) {
     _sentinel._prepend(value);
     _elementCount++;
   }
 
   void addAll(Iterable<E> iterable) {
     for (final E value in iterable) {
       _sentinel._prepend(value);
       _elementCount++;
     }
   }
 
   E removeLast() {
-    _DoubleLinkedQueueEntry lastEntry = _sentinel._previousLink;
+    _DoubleLinkedQueueEntry<E> lastEntry = _sentinel._previousLink;
     E result = lastEntry._remove();
     _elementCount--;
     return result;
   }
 
   E removeFirst() {
-    _DoubleLinkedQueueEntry firstEntry = _sentinel._nextLink;
+    _DoubleLinkedQueueEntry<E> firstEntry = _sentinel._nextLink;
     E result = firstEntry._remove();
     _elementCount--;
     return result;
   }
 
   bool remove(Object o) {
     _DoubleLinkedQueueEntry<E> entry = _sentinel._nextLink;
     while (!identical(entry, _sentinel)) {
       if (entry.element == o) {
         entry._remove();
@@ skipping 19 matching lines @@
 
   void removeWhere(bool test(E element)) {
     _filter(test, true);
   }
 
   void retainWhere(bool test(E element)) {
     _filter(test, false);
   }
 
   E get first {
-    _DoubleLinkedQueueEntry firstEntry = _sentinel._nextLink;
+    _DoubleLinkedQueueEntry<E> firstEntry = _sentinel._nextLink;
     return firstEntry.element;
   }
 
   E get last {
-    _DoubleLinkedQueueEntry lastEntry = _sentinel._previousLink;
+    _DoubleLinkedQueueEntry<E> lastEntry = _sentinel._previousLink;
     return lastEntry.element;
   }
 
   E get single {
     // Note that this throws correctly if the queue is empty
     // because reading element on the sentinel throws.
     if (identical(_sentinel._nextLink, _sentinel._previousLink)) {
-      _DoubleLinkedQueueEntry entry = _sentinel._nextLink;
+      _DoubleLinkedQueueEntry<E> entry = _sentinel._nextLink;
       return entry.element;
     }
     throw IterableElementError.tooMany();
   }
 
   DoubleLinkedQueueEntry<E> lastEntry() {
     return _sentinel.previousEntry();
   }
 
   DoubleLinkedQueueEntry<E> firstEntry() {
     return _sentinel.nextEntry();
   }
 
   bool get isEmpty {
     return (identical(_sentinel._nextLink, _sentinel));
   }
 
   void clear() {
     _sentinel._nextLink = _sentinel;
     _sentinel._previousLink = _sentinel;
     _elementCount = 0;
   }
 
   void forEachEntry(void f(DoubleLinkedQueueEntry<E> element)) {
     _DoubleLinkedQueueEntry<E> entry = _sentinel._nextLink;
     while (!identical(entry, _sentinel)) {
       _DoubleLinkedQueueEntry<E> nextEntry = entry._nextLink;
-      _DoubleLinkedQueueElement element = entry;
+      _DoubleLinkedQueueElement<E> element = entry;
       f(element);
       entry = nextEntry;
     }
   }
 
   _DoubleLinkedQueueIterator<E> get iterator {
     return new _DoubleLinkedQueueIterator<E>(_sentinel);
   }
 
   String toString() => IterableBase.iterableToFullString(this, '{', '}');
 }
 
 class _DoubleLinkedQueueIterator<E> implements Iterator<E> {
   _DoubleLinkedQueueSentinel<E> _sentinel;
   _DoubleLinkedQueueEntry<E> _nextEntry = null;
   E _current;
 
   _DoubleLinkedQueueIterator(_DoubleLinkedQueueSentinel<E> sentinel)
-      : _sentinel = sentinel, _nextEntry = sentinel._nextLink;
+      : _sentinel = sentinel,
+        _nextEntry = sentinel._nextLink;
 
   bool moveNext() {
     if (identical(_nextEntry, _sentinel)) {
       _current = null;
       _nextEntry = null;
       _sentinel = null;
       return false;
     }
-    _DoubleLinkedQueueElement elementEntry = _nextEntry;
+    _DoubleLinkedQueueElement<E> elementEntry = _nextEntry;
     if (elementEntry._queue == null) {
       throw new ConcurrentModificationError(_sentinel._queue);
     }
     _current = elementEntry.element;
     _nextEntry = elementEntry._nextLink;
     return true;
   }
 
   E get current => _current;
 }
@@ skipping 36 matching lines @@
    * The elements are added to the queue, as by [addLast], in the order given by
    * `elements.iterator`.
    *
    * All `elements` should be assignable to [E].
    */
   factory ListQueue.from(Iterable elements) {
     if (elements is List) {
       int length = elements.length;
       ListQueue<E> queue = new ListQueue(length + 1);
       assert(queue._table.length > length);
-      List sourceList = elements;
-      queue._table.setRange(0, length, sourceList, 0);
+      for (int i = 0; i < length; i++) {
+        queue._table[i] = elements[i] as Object/*=E*/;
+      }
       queue._tail = length;
       return queue;
     } else {
       int capacity = _INITIAL_CAPACITY;
       if (elements is EfficientLength) {
         capacity = elements.length;
       }
       ListQueue<E> result = new ListQueue<E>(capacity);
-      for (final E element in elements) {
-        result.addLast(element);
+      for (final element in elements) {
+        result.addLast(element as Object/*=E*/);
       }
       return result;
     }
   }
 
   // Iterable interface.
 
   Iterator<E> get iterator => new _ListQueueIterator<E>(this);
 
   void forEach(void action (E element)) {
@@ skipping 40 matching lines @@
     return list;
   }
 
   // Collection interface.
 
   void add(E value) {
     _add(value);
   }
 
   void addAll(Iterable<E> elements) {
-    if (elements is List) {
-      List list = elements;
+    if (elements is List/*<E>*/) {
+      List<E> list = elements;
       int addCount = list.length;
       int length = this.length;
       if (length + addCount >= _table.length) {
         _preGrow(length + addCount);
         // After preGrow, all elements are at the start of the list.
         _table.setRange(length, length + addCount, list, 0);
         _tail += addCount;
       } else {
         // Adding addCount elements won't reach _head.
         int endSpace = _table.length - _tail;
@@ skipping 222 matching lines @@
     _head = 0;
   }
 }
 
 /**
  * Iterator for a [ListQueue].
  *
  * Considers any add or remove operation a concurrent modification.
  */
 class _ListQueueIterator<E> implements Iterator<E> {
-  final ListQueue _queue;
+  final ListQueue<E> _queue;
   final int _end;
   final int _modificationCount;
   int _position;
   E _current;
 
-  _ListQueueIterator(ListQueue queue)
+  _ListQueueIterator(ListQueue<E> queue)
       : _queue = queue,
         _end = queue._tail,
         _modificationCount = queue._modificationCount,
         _position = queue._head;
 
   E get current => _current;
 
   bool moveNext() {
     _queue._checkModification(_modificationCount);
     if (_position == _end) {
       _current = null;
       return false;
     }
     _current = _queue._table[_position];
     _position = (_position + 1) & (_queue._table.length - 1);
     return true;
   }
 }