summaryrefslogtreecommitdiffstats
path: root/src/declarative/qml/qmlguard_p.h
blob: 42a4406c377d9f151cb6c8a797c29c0ed13f538d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef QMLGUARD_P_H
#define QMLGUARD_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists for the convenience
// of qapplication_*.cpp, qwidget*.cpp and qfiledialog.cpp.  This header
// file may change from version to version without notice, or even be removed.
//
// We mean it.
//

#include <QtCore/qglobal.h>

QT_BEGIN_NAMESPACE

class QObject;
template<class T>
class QmlGuard
{
    QObject *o;
    QmlGuard<QObject> *next;
    QmlGuard<QObject> **prev;
    friend class QmlDeclarativeData;
public:
    inline QmlGuard();
    inline QmlGuard(T *);
    inline QmlGuard(const QmlGuard<T> &);
    inline virtual ~QmlGuard();

    inline QmlGuard<T> &operator=(const QmlGuard<T> &o);
    inline QmlGuard<T> &operator=(T *);
    
    inline bool isNull() const
        { return !o; }

    inline T* operator->() const
        { return static_cast<T*>(const_cast<QObject*>(o)); }
    inline T& operator*() const
        { return *static_cast<T*>(const_cast<QObject*>(o)); }
    inline operator T*() const
        { return static_cast<T*>(const_cast<QObject*>(o)); }
    inline T* data() const
        { return static_cast<T*>(const_cast<QObject*>(o)); }

protected:
    virtual void objectDestroyed(T *) {}

private:
    inline void addGuard();
    inline void remGuard();
};

QT_END_NAMESPACE

#include "qmldeclarativedata_p.h"

QT_BEGIN_NAMESPACE

template<class T>
QmlGuard<T>::QmlGuard()
: o(0), next(0), prev(0)
{
}

template<class T>
QmlGuard<T>::QmlGuard(T *g)
: o(g), next(0), prev(0)
{
    if (o) addGuard();
}

template<class T>
QmlGuard<T>::QmlGuard(const QmlGuard<T> &g)
: o(g.o), next(0), prev(0)
{
    if (o) addGuard();
}

template<class T>
QmlGuard<T>::~QmlGuard()
{
    if (prev) remGuard();
    o = 0;
}

template<class T>
QmlGuard<T> &QmlGuard<T>::operator=(const QmlGuard<T> &g)
{
    if (g.o != o) {
        if (prev) remGuard();
        o = g.o;
        if (o) addGuard();
    }
    return *this;
}

template<class T>
QmlGuard<T> &QmlGuard<T>::operator=(T *g)
{
    if (g != o) {
        if (prev) remGuard();
        o = g;
        if (o) addGuard();
    }
    return *this;
}

QT_END_NAMESPACE

#endif // QMLGUARD_P_H