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39
40#ifndef QSEMAPHORE_H
41#define QSEMAPHORE_H
42
43#include <QtCore/qglobal.h>
44
45QT_REQUIRE_CONFIG(thread);
46
47QT_BEGIN_NAMESPACE
48
49class QSemaphorePrivate;
50
51class Q_CORE_EXPORT QSemaphore
52{
53public:
54 explicit QSemaphore(int n = 0);
55 ~QSemaphore();
56
57 void acquire(int n = 1);
58 bool tryAcquire(int n = 1);
59 bool tryAcquire(int n, int timeout);
60
61 void release(int n = 1);
62
63 int available() const;
64
65private:
66 Q_DISABLE_COPY(QSemaphore)
67
68 union {
69 QSemaphorePrivate *d;
70 QBasicAtomicInteger<quintptr> u; // ### Qt6: make 64-bit
71 };
72};
73
74class QSemaphoreReleaser
75{
76public:
77 QSemaphoreReleaser() = default;
78 explicit QSemaphoreReleaser(QSemaphore &sem, int n = 1) Q_DECL_NOTHROW
79 : m_sem(&sem), m_n(n) {}
80 explicit QSemaphoreReleaser(QSemaphore *sem, int n = 1) Q_DECL_NOTHROW
81 : m_sem(sem), m_n(n) {}
82 QSemaphoreReleaser(QSemaphoreReleaser &&other) Q_DECL_NOTHROW
83 : m_sem(other.m_sem), m_n(other.m_n)
84 { other.m_sem = nullptr; }
85 QSemaphoreReleaser &operator=(QSemaphoreReleaser &&other) Q_DECL_NOTHROW
86 { QSemaphoreReleaser moved(std::move(other)); swap(moved); return *this; }
87
88 ~QSemaphoreReleaser()
89 {
90 if (m_sem)
91 m_sem->release(m_n);
92 }
93
94 void swap(QSemaphoreReleaser &other) Q_DECL_NOTHROW
95 {
96 qSwap(m_sem, other.m_sem);
97 qSwap(m_n, other.m_n);
98 }
99
100 QSemaphore *semaphore() const Q_DECL_NOTHROW
101 { return m_sem; }
102
103 QSemaphore *cancel() Q_DECL_NOTHROW
104 {
105 QSemaphore *old = m_sem;
106 m_sem = nullptr;
107 return old;
108 }
109
110private:
111 QSemaphore *m_sem = nullptr;
112 int m_n;
113};
114
115QT_END_NAMESPACE
116
117#endif // QSEMAPHORE_H
118