gecko-dev/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 "nsIContent.h"
#include "nsRange.h"
#include "nsTArray.h"
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() = default;
NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(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(nsRange* 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();
virtual nsINode* GetCurrentNode();
virtual bool IsDone();
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;
bool mIsDone;
const Order mOrder;
friend void ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback&,
ContentIteratorBase&, const char*,
uint32_t);
friend void ImplCycleCollectionUnlink(ContentIteratorBase&);
};
// Each concreate class of ContentIteratorBase may be owned by another class
// which may be owned by JS. Therefore, all of them should be in the cycle
// collection. However, we cannot make non-refcountable classes only with the
// macros. So, we need to make them cycle collectable without the macros.
inline void ImplCycleCollectionTraverse(
nsCycleCollectionTraversalCallback& aCallback, ContentIteratorBase& aField,
const char* aName, uint32_t aFlags = 0) {
ImplCycleCollectionTraverse(aCallback, aField.mCurNode, aName, aFlags);
ImplCycleCollectionTraverse(aCallback, aField.mFirst, aName, aFlags);
ImplCycleCollectionTraverse(aCallback, aField.mLast, aName, aFlags);
ImplCycleCollectionTraverse(aCallback, aField.mClosestCommonInclusiveAncestor,
aName, aFlags);
}
inline void ImplCycleCollectionUnlink(ContentIteratorBase& aField) {
ImplCycleCollectionUnlink(aField.mCurNode);
ImplCycleCollectionUnlink(aField.mFirst);
ImplCycleCollectionUnlink(aField.mLast);
ImplCycleCollectionUnlink(aField.mClosestCommonInclusiveAncestor);
}
/**
* 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(nsRange* 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;
virtual void Next() override;
virtual void Prev() override;
// Must override these because we don't do PositionAt
virtual void First() override;
// Must override these because we don't do PositionAt
virtual void Last() override;
virtual 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<nsRange> 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