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39
40#ifndef QRECURSIONWATCHER_P_H
41#define QRECURSIONWATCHER_P_H
42
43//
44// W A R N I N G
45// -------------
46//
47// This file is not part of the Qt API. It exists purely as an
48// implementation detail. This header file may change from version to
49// version without notice, or even be removed.
50//
51// We mean it.
52//
53
54#include <QtCore/qglobal.h>
55
56QT_BEGIN_NAMESPACE
57
58class QRecursionNode;
59class QRecursionNode {
60public:
61 inline QRecursionNode();
62 bool *_r;
63};
64
65template<class T, QRecursionNode T::*Node>
66class QRecursionWatcher {
67public:
68 inline QRecursionWatcher(T *);
69 inline ~QRecursionWatcher();
70 inline bool hasRecursed() const;
71private:
72 T *_t;
73 bool _r;
74};
75
76QRecursionNode::QRecursionNode()
77: _r(nullptr)
78{
79}
80
81template<class T, QRecursionNode T::*Node>
82QRecursionWatcher<T, Node>::QRecursionWatcher(T *t)
83: _t(t), _r(false)
84{
85 if ((_t->*Node)._r) *(_t->*Node)._r = true;
86 (_t->*Node)._r = &_r;
87}
88
89template<class T, QRecursionNode T::*Node>
90QRecursionWatcher<T, Node>::~QRecursionWatcher()
91{
92 if ((_t->*Node)._r == &_r) (_t->*Node)._r = nullptr;
93}
94
95template<class T, QRecursionNode T::*Node>
96bool QRecursionWatcher<T, Node>::hasRecursed() const
97{
98 return _r;
99}
100
101QT_END_NAMESPACE
102
103#endif // QRECURSIONWATCHER_P_H
104

source code of qtdeclarative/src/qml/qml/ftw/qrecursionwatcher_p.h