1 files changed, 257 insertions, 0 deletions
diff --git a/dom/base/ContentIterator.h b/dom/base/ContentIterator.h
new file mode 100644
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--- /dev/null
+++ b/dom/base/ContentIterator.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ContentIterator_h
+#define mozilla_ContentIterator_h
+
+#include "mozilla/RangeBoundary.h"
+#include "nsCOMPtr.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsRange.h"
+#include "nsTArray.h"
+
+class nsIContent;
+class nsINode;
+
+namespace mozilla {
+
+/**
+ * ContentIteratorBase is a base class of PostContentIterator,
+ * PreContentIterator and ContentSubtreeIterator.  Making each concrete
+ * classes "final", compiler can avoid virtual calls if they are treated
+ * by the users directly.
+ */
+class ContentIteratorBase {
+ public:
+  ContentIteratorBase() = delete;
+  ContentIteratorBase(const ContentIteratorBase&) = delete;
+  ContentIteratorBase& operator=(const ContentIteratorBase&) = delete;
+  virtual ~ContentIteratorBase();
+
+  /**
+   * Allows to iterate over the inclusive descendants
+   * (https://dom.spec.whatwg.org/#concept-tree-inclusive-descendant) of
+   * aRoot.
+   */
+  virtual nsresult Init(nsINode* aRoot);
+
+  virtual nsresult Init(dom::AbstractRange* aRange);
+  virtual nsresult Init(nsINode* aStartContainer, uint32_t aStartOffset,
+                        nsINode* aEndContainer, uint32_t aEndOffset);
+  virtual nsresult Init(const RawRangeBoundary& aStart,
+                        const RawRangeBoundary& aEnd);
+
+  virtual void First();
+  virtual void Last();
+  virtual void Next();
+  virtual void Prev();
+
+  nsINode* GetCurrentNode() const { return mCurNode; }
+
+  bool IsDone() const { return !mCurNode; }
+
+  virtual nsresult PositionAt(nsINode* aCurNode);
+
+ protected:
+  enum class Order {
+    Pre, /*!< <https://en.wikipedia.org/wiki/Tree_traversal#Pre-order_(NLR)>.
+          */
+    Post /*!< <https://en.wikipedia.org/wiki/Tree_traversal#Post-order_(LRN)>.
+          */
+  };
+
+  explicit ContentIteratorBase(Order aOrder);
+
+  class Initializer;
+
+  /**
+   * Callers must guarantee that:
+   * - Neither aStartContainer nor aEndContainer is nullptr.
+   * - aStartOffset and aEndOffset are valid for its container.
+   * - The start point and the end point are in document order.
+   */
+  nsresult InitInternal(const RawRangeBoundary& aStart,
+                        const RawRangeBoundary& aEnd);
+
+  // Recursively get the deepest first/last child of aRoot.  This will return
+  // aRoot itself if it has no children.
+  static nsINode* GetDeepFirstChild(nsINode* aRoot);
+  static nsIContent* GetDeepFirstChild(nsIContent* aRoot);
+  static nsINode* GetDeepLastChild(nsINode* aRoot);
+  static nsIContent* GetDeepLastChild(nsIContent* aRoot);
+
+  // Get the next/previous sibling of aNode, or its parent's, or grandparent's,
+  // etc.  Returns null if aNode and all its ancestors have no next/previous
+  // sibling.
+  static nsIContent* GetNextSibling(nsINode* aNode);
+  static nsIContent* GetPrevSibling(nsINode* aNode);
+
+  nsINode* NextNode(nsINode* aNode);
+  nsINode* PrevNode(nsINode* aNode);
+
+  void SetEmpty();
+
+  nsCOMPtr<nsINode> mCurNode;
+  nsCOMPtr<nsINode> mFirst;
+  nsCOMPtr<nsINode> mLast;
+  // See <https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor>.
+  nsCOMPtr<nsINode> mClosestCommonInclusiveAncestor;
+
+  const Order mOrder;
+
+  friend void ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback&,
+                                          ContentIteratorBase&, const char*,
+                                          uint32_t);
+  friend void ImplCycleCollectionUnlink(ContentIteratorBase&);
+};
+
+/**
+ * A simple iterator class for traversing the content in "close tag" order.
+ */
+class PostContentIterator final : public ContentIteratorBase {
+ public:
+  PostContentIterator() : ContentIteratorBase(Order::Post) {}
+  PostContentIterator(const PostContentIterator&) = delete;
+  PostContentIterator& operator=(const PostContentIterator&) = delete;
+  virtual ~PostContentIterator() = default;
+  friend void ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback&,
+                                          PostContentIterator&, const char*,
+                                          uint32_t);
+  friend void ImplCycleCollectionUnlink(PostContentIterator&);
+};
+
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback, PostContentIterator& aField,
+    const char* aName, uint32_t aFlags = 0) {
+  ImplCycleCollectionTraverse(
+      aCallback, static_cast<ContentIteratorBase&>(aField), aName, aFlags);
+}
+
+inline void ImplCycleCollectionUnlink(PostContentIterator& aField) {
+  ImplCycleCollectionUnlink(static_cast<ContentIteratorBase&>(aField));
+}
+
+/**
+ * A simple iterator class for traversing the content in "start tag" order.
+ */
+class PreContentIterator final : public ContentIteratorBase {
+ public:
+  PreContentIterator() : ContentIteratorBase(Order::Pre) {}
+  PreContentIterator(const PreContentIterator&) = delete;
+  PreContentIterator& operator=(const PreContentIterator&) = delete;
+  virtual ~PreContentIterator() = default;
+  friend void ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback&,
+                                          PreContentIterator&, const char*,
+                                          uint32_t);
+  friend void ImplCycleCollectionUnlink(PreContentIterator&);
+};
+
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback, PreContentIterator& aField,
+    const char* aName, uint32_t aFlags = 0) {
+  ImplCycleCollectionTraverse(
+      aCallback, static_cast<ContentIteratorBase&>(aField), aName, aFlags);
+}
+
+inline void ImplCycleCollectionUnlink(PreContentIterator& aField) {
+  ImplCycleCollectionUnlink(static_cast<ContentIteratorBase&>(aField));
+}
+
+/**
+ *  A simple iterator class for traversing the content in "top subtree" order.
+ */
+class ContentSubtreeIterator final : public ContentIteratorBase {
+ public:
+  ContentSubtreeIterator() : ContentIteratorBase(Order::Pre) {}
+  ContentSubtreeIterator(const ContentSubtreeIterator&) = delete;
+  ContentSubtreeIterator& operator=(const ContentSubtreeIterator&) = delete;
+  virtual ~ContentSubtreeIterator() = default;
+
+  /**
+   * Not supported.
+   */
+  virtual nsresult Init(nsINode* aRoot) override;
+
+  virtual nsresult Init(dom::AbstractRange* aRange) override;
+  virtual nsresult Init(nsINode* aStartContainer, uint32_t aStartOffset,
+                        nsINode* aEndContainer, uint32_t aEndOffset) override;
+  virtual nsresult Init(const RawRangeBoundary& aStartBoundary,
+                        const RawRangeBoundary& aEndBoundary) override;
+
+  void Next() override;
+  void Prev() override;
+  // Must override these because we don't do PositionAt
+  void First() override;
+  // Must override these because we don't do PositionAt
+  void Last() override;
+
+  nsresult PositionAt(nsINode* aCurNode) override;
+
+  friend void ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback&,
+                                          ContentSubtreeIterator&, const char*,
+                                          uint32_t);
+  friend void ImplCycleCollectionUnlink(ContentSubtreeIterator&);
+
+ private:
+  /**
+   * See <https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor>.
+   */
+  void CacheInclusiveAncestorsOfEndContainer();
+
+  /**
+   * @return may be nullptr.
+   */
+  nsIContent* DetermineCandidateForFirstContent() const;
+
+  /**
+   * @return may be nullptr.
+   */
+  nsIContent* DetermineCandidateForLastContent() const;
+
+  /**
+   * @return may be nullptr.
+   */
+  nsIContent* DetermineFirstContent() const;
+
+  /**
+   * @return may be nullptr.
+   */
+  nsIContent* DetermineLastContent() const;
+
+  /**
+   * Callers must guarantee that mRange isn't nullptr and is positioned.
+   */
+  nsresult InitWithRange();
+
+  // Returns the highest inclusive ancestor of aNode that's in the range
+  // (possibly aNode itself).  Returns null if aNode is null, or is not itself
+  // in the range.  A node is in the range if (node, 0) comes strictly after
+  // the range endpoint, and (node, node.length) comes strictly before it, so
+  // the range's start and end nodes will never be considered "in" it.
+  nsIContent* GetTopAncestorInRange(nsINode* aNode) const;
+
+  RefPtr<dom::AbstractRange> mRange;
+
+  // See <https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor>.
+  AutoTArray<nsIContent*, 8> mInclusiveAncestorsOfEndContainer;
+};
+
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback,
+    ContentSubtreeIterator& aField, const char* aName, uint32_t aFlags = 0) {
+  ImplCycleCollectionTraverse(aCallback, aField.mRange, aName, aFlags);
+  ImplCycleCollectionTraverse(
+      aCallback, static_cast<ContentIteratorBase&>(aField), aName, aFlags);
+}
+
+inline void ImplCycleCollectionUnlink(ContentSubtreeIterator& aField) {
+  ImplCycleCollectionUnlink(aField.mRange);
+  ImplCycleCollectionUnlink(static_cast<ContentIteratorBase&>(aField));
+}
+
+}  // namespace mozilla
+
+#endif  // #ifndef mozilla_ContentIterator_h