/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 * Copyright (C) 2000 Frederik Holljen (frederik.holljen@hig.no)
 * Copyright (C) 2001 Peter Kelly (pmk@post.com)
 * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
 * Copyright (C) 2004-2019 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#pragma once

#include "ExceptionOr.h"
#include "NodeFilter.h"
#include "ScriptWrappable.h"
#include "Traversal.h"
#include <wtf/IsoMalloc.h>

namespace WebCore {

class NodeIterator final : public ScriptWrappable, public RefCounted<NodeIterator>, public NodeIteratorBase {
    WTF_MAKE_ISO_ALLOCATED_EXPORT(NodeIterator, WEBCORE_EXPORT);
public:
    static Ref<NodeIterator> create(Node&, unsigned whatToShow, RefPtr<NodeFilter>&&);
    WEBCORE_EXPORT ~NodeIterator();

    WEBCORE_EXPORT ExceptionOr<RefPtr<Node>> nextNode();
    WEBCORE_EXPORT ExceptionOr<RefPtr<Node>> previousNode();
    void detach() { } // This is now a no-op as per the DOM specification.

    Node* referenceNode() const { return m_referenceNode.node.get(); }
    bool pointerBeforeReferenceNode() const { return m_referenceNode.isPointerBeforeNode; }

    // This function is called before any node is removed from the document tree.
    void nodeWillBeRemoved(Node&);

private:
    NodeIterator(Node&, unsigned whatToShow, RefPtr<NodeFilter>&&);

    struct NodePointer {
        RefPtr<Node> node;
        bool isPointerBeforeNode { true };

        NodePointer() = default;
        NodePointer(Node&, bool);

        void clear();
        bool moveToNext(Node& root);
        bool moveToPrevious(Node& root);
    };

    void updateForNodeRemoval(Node& nodeToBeRemoved, NodePointer&) const;

    NodePointer m_referenceNode;
    NodePointer m_candidateNode;
};

} // namespace WebCore