/*  This file is part of the KDE project.

Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

This library is free software: you can redistribute it and/or modify

it under the terms of the GNU Lesser General Public License as published by

the Free Software Foundation, either version 2.1 or 3 of the License.

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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License

along with this library.  If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef OBJECTTREE_H

#define OBJECTTREE_H

#include <QObject>

#include <QStack>

QT_BEGIN_NAMESPACE

namespace ObjectTree

{

/**

 * Depth-first iterator for QObject tree

 */

class DepthFirstConstIterator

{

public:

    DepthFirstConstIterator();

    DepthFirstConstIterator(const QObject& root);

    DepthFirstConstIterator& operator++();

    inline bool operator==(const DepthFirstConstIterator& other) const

    { return other.m_pointee == m_pointee; }

    inline bool operator!=(const DepthFirstConstIterator& other) const

    { return other.m_pointee != m_pointee; }

    inline const QObject* operator->() const { return m_pointee; }

    inline const QObject& operator*() const { return *m_pointee; }

private:

    void backtrack();

private:

    const QObject* m_pointee;

    QStack<int> m_history;

};

/**

 * Ancestor iterator for QObject tree

 */

class AncestorConstIterator

{

public:

    AncestorConstIterator();

    AncestorConstIterator(const QObject& root);

    inline AncestorConstIterator& operator++()

    { m_ancestors.pop(); return *this; }

    inline bool operator==(const AncestorConstIterator& other) const

    { return other.m_ancestors == m_ancestors; }

    inline bool operator!=(const AncestorConstIterator& other) const

    { return other.m_ancestors != m_ancestors; }

    inline const QObject* operator->() const { return m_ancestors.top(); }

    inline const QObject& operator*() const { return *m_ancestors.top(); }

private:

    QStack<const QObject*> m_ancestors;

};

/**

 * Generic algorithm for visiting nodes in an object tree.  Nodes in the

 * tree are visited in a const context, therefore they are not modified

 * by this algorithm.

 *

 * Visitor must provide functions with the following signatures:

 *

 *      Called before visit begins

 *          void visitPrepare()

 *

 *      Called on each node visited

 *          void visitNode(const QObject& object)

 *

 *      Called when visit is complete

 *          void visitComplete()

 */

template <class Iterator, class Visitor>

void visit(Iterator begin, Iterator end, Visitor& visitor)

{

    visitor.visitPrepare();

    for ( ; begin != end; ++begin)

        visitor.visitNode(*begin);

    visitor.visitComplete();

}

} // namespace ObjectTree

QT_END_NAMESPACE

#endif // OBJECTTREE_H