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39
40#ifndef QREFCOUNT_H
41#define QREFCOUNT_H
42
43#include <QtCore/qatomic.h>
44
45QT_BEGIN_NAMESPACE
46
47
48namespace QtPrivate
49{
50
51class RefCount
52{
53public:
54 inline bool ref() Q_DECL_NOTHROW {
55 int count = atomic.load();
56#if !defined(QT_NO_UNSHARABLE_CONTAINERS)
57 if (count == 0) // !isSharable
58 return false;
59#endif
60 if (count != -1) // !isStatic
61 atomic.ref();
62 return true;
63 }
64
65 inline bool deref() Q_DECL_NOTHROW {
66 int count = atomic.load();
67#if !defined(QT_NO_UNSHARABLE_CONTAINERS)
68 if (count == 0) // !isSharable
69 return false;
70#endif
71 if (count == -1) // isStatic
72 return true;
73 return atomic.deref();
74 }
75
76#if !defined(QT_NO_UNSHARABLE_CONTAINERS)
77 bool setSharable(bool sharable) Q_DECL_NOTHROW
78 {
79 Q_ASSERT(!isShared());
80 if (sharable)
81 return atomic.testAndSetRelaxed(0, 1);
82 else
83 return atomic.testAndSetRelaxed(1, 0);
84 }
85
86 bool isSharable() const Q_DECL_NOTHROW
87 {
88 // Sharable === Shared ownership.
89 return atomic.load() != 0;
90 }
91#endif
92
93 bool isStatic() const Q_DECL_NOTHROW
94 {
95 // Persistent object, never deleted
96 return atomic.load() == -1;
97 }
98
99 bool isShared() const Q_DECL_NOTHROW
100 {
101 int count = atomic.load();
102 return (count != 1) && (count != 0);
103 }
104
105 void initializeOwned() Q_DECL_NOTHROW { atomic.store(1); }
106 void initializeUnsharable() Q_DECL_NOTHROW { atomic.store(0); }
107
108 QBasicAtomicInt atomic;
109};
110
111}
112
113#define Q_REFCOUNT_INITIALIZE_STATIC { Q_BASIC_ATOMIC_INITIALIZER(-1) }
114
115QT_END_NAMESPACE
116
117#endif
118