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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) noexcept
79 : m_sem(&sem), m_n(n) {}
80 explicit QSemaphoreReleaser(QSemaphore *sem, int n = 1) noexcept
81 : m_sem(sem), m_n(n) {}
82 QSemaphoreReleaser(QSemaphoreReleaser &&other) noexcept
83 : m_sem(other.cancel()), m_n(other.m_n) {}
84 QSemaphoreReleaser &operator=(QSemaphoreReleaser &&other) noexcept
85 { QSemaphoreReleaser moved(std::move(other)); swap(other&: moved); return *this; }
86
87 ~QSemaphoreReleaser()
88 {
89 if (m_sem)
90 m_sem->release(n: m_n);
91 }
92
93 void swap(QSemaphoreReleaser &other) noexcept
94 {
95 qSwap(value1&: m_sem, value2&: other.m_sem);
96 qSwap(value1&: m_n, value2&: other.m_n);
97 }
98
99 QSemaphore *semaphore() const noexcept
100 { return m_sem; }
101
102 QSemaphore *cancel() noexcept
103 {
104 return qExchange(t&: m_sem, newValue: nullptr);
105 }
106
107private:
108 QSemaphore *m_sem = nullptr;
109 int m_n;
110};
111
112QT_END_NAMESPACE
113
114#endif // QSEMAPHORE_H
115

source code of qtbase/src/corelib/thread/qsemaphore.h