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41
42 #ifndef QDECLARATIVEGUARD_P_H
43 #define QDECLARATIVEGUARD_P_H
44
45 //
46 // W A R N I N G
47 // -------------
48 //
49 // This file is not part of the Qt API. It exists for the convenience
50 // of qapplication_*.cpp, qwidget*.cpp and qfiledialog.cpp. This header
51 // file may change from version to version without notice, or even be removed.
52 //
53 // We mean it.
54 //
55
56 #include <QtCore/qglobal.h>
57 #include <QtCore/qvariant.h>
58 #include <private/qdeclarativedata_p.h>
59
60 QT_BEGIN_NAMESPACE
61
62 class QDeclarativeGuardImpl
63 {
64 public:
65 inline QDeclarativeGuardImpl();
66 inline QDeclarativeGuardImpl(QObject *);
67 inline QDeclarativeGuardImpl(const QDeclarativeGuardImpl &);
68 inline ~QDeclarativeGuardImpl();
69
70 QObject *o;
71 QDeclarativeGuardImpl *next;
72 QDeclarativeGuardImpl **prev;
73
74 inline void addGuard();
75 inline void remGuard();
76 };
77
78 class QObject;
79 template<class T>
80 class QDeclarativeGuard : private QDeclarativeGuardImpl
81 {
82 friend class QDeclarativeData;
83 public:
84 inline QDeclarativeGuard();
85 inline QDeclarativeGuard(T *);
86 inline QDeclarativeGuard(const QDeclarativeGuard<T> &);
87 inline virtual ~QDeclarativeGuard();
88
89 inline QDeclarativeGuard<T> &operator=(const QDeclarativeGuard<T> &o);
90 inline QDeclarativeGuard<T> &operator=(T *);
91
92 inline T *object() const;
93 inline void setObject(T *g);
94
isNull()95 inline bool isNull() const
96 { return !o; }
97
98 inline T* operator->() const
99 { return static_cast<T*>(const_cast<QObject*>(o)); }
100 inline T& operator*() const
101 { return *static_cast<T*>(const_cast<QObject*>(o)); }
102 inline operator T*() const
103 { return static_cast<T*>(const_cast<QObject*>(o)); }
data()104 inline T* data() const
105 { return static_cast<T*>(const_cast<QObject*>(o)); }
106
107 protected:
objectDestroyed(T *)108 virtual void objectDestroyed(T *) {}
109 };
110
QDeclarativeGuardImpl()111 QDeclarativeGuardImpl::QDeclarativeGuardImpl()
112 : o(0), next(0), prev(0)
113 {
114 }
115
QDeclarativeGuardImpl(QObject * g)116 QDeclarativeGuardImpl::QDeclarativeGuardImpl(QObject *g)
117 : o(g), next(0), prev(0)
118 {
119 if (o) addGuard();
120 }
121
QDeclarativeGuardImpl(const QDeclarativeGuardImpl & g)122 QDeclarativeGuardImpl::QDeclarativeGuardImpl(const QDeclarativeGuardImpl &g)
123 : o(g.o), next(0), prev(0)
124 {
125 if (o) addGuard();
126 }
127
~QDeclarativeGuardImpl()128 QDeclarativeGuardImpl::~QDeclarativeGuardImpl()
129 {
130 if (prev) remGuard();
131 o = 0;
132 }
133
addGuard()134 void QDeclarativeGuardImpl::addGuard()
135 {
136 Q_ASSERT(!prev);
137
138 if (QObjectPrivate::get(o)->wasDeleted)
139 return;
140
141 QDeclarativeData *data = QDeclarativeData::get(o, true);
142 next = data->guards;
143 if (next) next->prev = &next;
144 data->guards = this;
145 prev = &data->guards;
146 }
147
remGuard()148 void QDeclarativeGuardImpl::remGuard()
149 {
150 Q_ASSERT(prev);
151
152 if (next) next->prev = prev;
153 *prev = next;
154 next = 0;
155 prev = 0;
156 }
157
158 template<class T>
QDeclarativeGuard()159 QDeclarativeGuard<T>::QDeclarativeGuard()
160 {
161 }
162
163 template<class T>
QDeclarativeGuard(T * g)164 QDeclarativeGuard<T>::QDeclarativeGuard(T *g)
165 : QDeclarativeGuardImpl(g)
166 {
167 }
168
169 template<class T>
QDeclarativeGuard(const QDeclarativeGuard<T> & g)170 QDeclarativeGuard<T>::QDeclarativeGuard(const QDeclarativeGuard<T> &g)
171 : QDeclarativeGuardImpl(g)
172 {
173 }
174
175 template<class T>
~QDeclarativeGuard()176 QDeclarativeGuard<T>::~QDeclarativeGuard()
177 {
178 }
179
180 template<class T>
181 QDeclarativeGuard<T> &QDeclarativeGuard<T>::operator=(const QDeclarativeGuard<T> &g)
182 {
183 setObject(g.object());
184 return *this;
185 }
186
187 template<class T>
188 QDeclarativeGuard<T> &QDeclarativeGuard<T>::operator=(T *g)
189 {
190 setObject(g);
191 return *this;
192 }
193
194 template<class T>
object()195 T *QDeclarativeGuard<T>::object() const
196 {
197 return static_cast<T *>(o);
198 };
199
200 template<class T>
setObject(T * g)201 void QDeclarativeGuard<T>::setObject(T *g)
202 {
203 if (g != o) {
204 if (prev) remGuard();
205 o = g;
206 if (o) addGuard();
207 }
208 }
209
210 QT_END_NAMESPACE
211
212 Q_DECLARE_METATYPE(QDeclarativeGuard<QObject>)
213
214 #endif // QDECLARATIVEGUARD_P_H
215