1 /*  This file is part of the KDE project.

     2 

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

     4 

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

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

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

     8 

     9 This library is distributed in the hope that it will be useful,

    10 but WITHOUT ANY WARRANTY; without even the implied warranty of

    11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    12 GNU Lesser General Public License for more details.

    13 

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

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

    16 

    17 */

    18 

    19 #ifndef OBJECTTREE_H

    20 #define OBJECTTREE_H

    21 

    22 #include <QObject>

    23 #include <QStack>

    24 

    25 QT_BEGIN_NAMESPACE

    26 

    27 namespace ObjectTree

    28 {

    29 

    30 /**

    31  * Depth-first iterator for QObject tree

    32  */

    33 class DepthFirstConstIterator

    34 {

    35 public:

    36     DepthFirstConstIterator();

    37     DepthFirstConstIterator(const QObject& root);

    38 

    39     DepthFirstConstIterator& operator++();

    40 

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

    42     { return other.m_pointee == m_pointee; }

    43 

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

    45     { return other.m_pointee != m_pointee; }

    46 

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

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

    49 

    50 private:

    51     void backtrack();

    52 

    53 private:

    54     const QObject* m_pointee;

    55     QStack<int> m_history;

    56 };

    57 

    58 /**

    59  * Ancestor iterator for QObject tree

    60  */

    61 class AncestorConstIterator

    62 {

    63 public:

    64     AncestorConstIterator();

    65     AncestorConstIterator(const QObject& root);

    66 

    67     inline AncestorConstIterator& operator++()

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

    69 

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

    71     { return other.m_ancestors == m_ancestors; }

    72 

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

    74     { return other.m_ancestors != m_ancestors; }

    75 

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

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

    78 

    79 private:

    80     QStack<const QObject*> m_ancestors;

    81 

    82 };

    83 

    84 /**

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

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

    87  * by this algorithm.

    88  *

    89  * Visitor must provide functions with the following signatures:

    90  *

    91  *      Called before visit begins

    92  *          void visitPrepare()

    93  *

    94  *      Called on each node visited

    95  *          void visitNode(const QObject& object)

    96  *

    97  *      Called when visit is complete

    98  *          void visitComplete()

    99  */

   100 template <class Iterator, class Visitor>

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

   102 {

   103     visitor.visitPrepare();

   104 

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

   106         visitor.visitNode(*begin);

   107 

   108     visitor.visitComplete();

   109 }

   110 

   111 } // namespace ObjectTree

   112 

   113 QT_END_NAMESPACE

   114 

   115 #endif // OBJECTTREE_H