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 // Copyright (C) 2016 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
 #ifndef QMUTEX_H
 #define QMUTEX_H
 
 #include <QtCore/qglobal.h>
 #include <QtCore/qatomic.h>
 #include <QtCore/qdeadlinetimer.h>
 #include <QtCore/qtsan_impl.h>
 
 #include <chrono>
 
 QT_BEGIN_NAMESPACE
 
 #if QT_CONFIG(thread) || defined(Q_QDOC)
 
 class QMutex;
 class QRecursiveMutex;
 class QMutexPrivate;
 
 class Q_CORE_EXPORT QBasicMutex
 {
     Q_DISABLE_COPY_MOVE(QBasicMutex)
 protected:
     static constexpr bool FutexAlwaysAvailable =
 #if defined(Q_OS_FREEBSD) || defined(Q_OS_LINUX) || defined(Q_OS_WIN) // these platforms use futex
             true
 #else
             false
 #endif
             ;
 
 public:
     constexpr QBasicMutex()
         : d_ptr(nullptr)
     {}
 
     // BasicLockable concept
     inline void lock() noexcept(FutexAlwaysAvailable) {
         QtTsan::mutexPreLock(this, 0u);
 
         if (!fastTryLock())
             lockInternal();
 
         QtTsan::mutexPostLock(this, 0u, 0);
     }
 
     // BasicLockable concept
     inline void unlock() noexcept {
         Q_ASSERT(d_ptr.loadRelaxed()); //mutex must be locked
 
         QtTsan::mutexPreUnlock(this, 0u);
 
         if (!fastTryUnlock())
             unlockInternal();
 
         QtTsan::mutexPostUnlock(this, 0u);
     }
 
     bool tryLock() noexcept {
         unsigned tsanFlags = QtTsan::TryLock;
         QtTsan::mutexPreLock(this, tsanFlags);
 
         const bool success = fastTryLock();
 
         if (!success)
             tsanFlags |= QtTsan::TryLockFailed;
         QtTsan::mutexPostLock(this, tsanFlags, 0);
 
         return success;
     }
 
     // Lockable concept
     bool try_lock() noexcept { return tryLock(); }
 
 private:
     inline bool fastTryLock() noexcept
     {
         if (d_ptr.loadRelaxed() != nullptr)
             return false;
         return d_ptr.testAndSetAcquire(nullptr, dummyLocked());
     }
     inline bool fastTryUnlock() noexcept {
         return d_ptr.testAndSetRelease(dummyLocked(), nullptr);
     }
 
     void lockInternal() noexcept(FutexAlwaysAvailable);
     bool lockInternal(QDeadlineTimer timeout) noexcept(FutexAlwaysAvailable);
 #if QT_VERSION < QT_VERSION_CHECK(7, 0, 0)
     bool lockInternal(int timeout) noexcept(FutexAlwaysAvailable);
 #endif
     void unlockInternal() noexcept;
 #if QT_CORE_REMOVED_SINCE(6, 9)
     void destroyInternal(QMutexPrivate *d);
 #endif
     void destroyInternal(void *d);
 
     QBasicAtomicPointer<QMutexPrivate> d_ptr;
     static inline QMutexPrivate *dummyLocked() {
         return reinterpret_cast<QMutexPrivate *>(quintptr(1));
     }
 
     friend class QMutex;
     friend class QMutexPrivate;
 };
 
 class Q_CORE_EXPORT QMutex : public QBasicMutex
 {
 public:
     constexpr QMutex() = default;
     ~QMutex()
     {
         QMutexPrivate *d = d_ptr.loadRelaxed();
         if (d)
             destroyInternal(d);
     }
 
 #ifdef Q_QDOC
     inline void lock() noexcept(FutexAlwaysAvailable);
     inline void unlock() noexcept;
     bool tryLock() noexcept;
 #endif
 
     // Lockable concept
     bool try_lock() noexcept { return tryLock(); }
 
 
     using QBasicMutex::tryLock;
     bool tryLock(int timeout) noexcept(FutexAlwaysAvailable)
     {
         return tryLock(QDeadlineTimer(timeout));
     }
 
     bool tryLock(QDeadlineTimer timeout) noexcept(FutexAlwaysAvailable)
     {
         unsigned tsanFlags = QtTsan::TryLock;
         QtTsan::mutexPreLock(this, tsanFlags);
 
         bool success = fastTryLock();
 
         if (success) {
             QtTsan::mutexPostLock(this, tsanFlags, 0);
             return success;
         }
 
         success = lockInternal(timeout);
 
         if (!success)
             tsanFlags |= QtTsan::TryLockFailed;
         QtTsan::mutexPostLock(this, tsanFlags, 0);
 
         return success;
     }
 
     // TimedLockable concept
     template <class Rep, class Period>
     bool try_lock_for(std::chrono::duration<Rep, Period> duration)
     {
         return tryLock(QDeadlineTimer(duration));
     }
 
     // TimedLockable concept
     template<class Clock, class Duration>
     bool try_lock_until(std::chrono::time_point<Clock, Duration> timePoint)
     {
         return tryLock(QDeadlineTimer(timePoint));
     }
 };
 
 class Q_CORE_EXPORT QRecursiveMutex
 {
     Q_DISABLE_COPY_MOVE(QRecursiveMutex)
     // written to by the thread that first owns 'mutex';
     // read during attempts to acquire ownership of 'mutex' from any other thread:
     QAtomicPointer<void> owner = nullptr;
     // only ever accessed from the thread that owns 'mutex':
     uint count = 0;
     QMutex mutex;
     static constexpr bool LockIsNoexcept = noexcept(std::declval<QMutex>().lock());
 
 public:
     constexpr QRecursiveMutex() = default;
     ~QRecursiveMutex();
 
 
     // BasicLockable concept
     void lock() noexcept(LockIsNoexcept)
     { tryLock(QDeadlineTimer(QDeadlineTimer::Forever)); }
     QT_CORE_INLINE_SINCE(6, 6)
     bool tryLock(int timeout) noexcept(LockIsNoexcept);
     bool tryLock(QDeadlineTimer timer = {}) noexcept(LockIsNoexcept);
     // BasicLockable concept
     void unlock() noexcept;
 
     // Lockable concept
     bool try_lock() noexcept(LockIsNoexcept) { return tryLock(); }
 
     // TimedLockable concept
     template <class Rep, class Period>
     bool try_lock_for(std::chrono::duration<Rep, Period> duration)
     {
         return tryLock(QDeadlineTimer(duration));
     }
 
     // TimedLockable concept
     template<class Clock, class Duration>
     bool try_lock_until(std::chrono::time_point<Clock, Duration> timePoint)
     {
         return tryLock(QDeadlineTimer(timePoint));
     }
 };
 
 #if QT_CORE_INLINE_IMPL_SINCE(6, 6)
 bool QRecursiveMutex::tryLock(int timeout) noexcept(LockIsNoexcept)
 {
     return tryLock(QDeadlineTimer(timeout));
 }
 #endif
 
 template <typename Mutex>
 class QMutexLocker
 {
 #ifdef Q_CC_GHS
     // internal compiler error otherwise
     static constexpr bool LockIsNoexcept = false;
 #else
     static constexpr bool LockIsNoexcept = noexcept(std::declval<Mutex>().lock());
 #endif
 public:
     Q_NODISCARD_CTOR
     inline explicit QMutexLocker(Mutex *mutex) noexcept(LockIsNoexcept)
     {
         m_mutex = mutex;
         if (Q_LIKELY(mutex)) {
             mutex->lock();
             m_isLocked = true;
         }
     }
 
     Q_NODISCARD_CTOR
     inline QMutexLocker(QMutexLocker &&other) noexcept
         : m_mutex(std::exchange(other.m_mutex, nullptr)),
           m_isLocked(std::exchange(other.m_isLocked, false))
     {}
 
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QMutexLocker)
 
     inline ~QMutexLocker()
     {
         if (m_isLocked)
             unlock();
     }
 
     inline bool isLocked() const noexcept
     {
         return m_isLocked;
     }
 
     inline void unlock() noexcept
     {
         Q_ASSERT(m_isLocked);
         m_mutex->unlock();
         m_isLocked = false;
     }
 
     inline void relock() noexcept(LockIsNoexcept)
     {
         Q_ASSERT(!m_isLocked);
         m_mutex->lock();
         m_isLocked = true;
     }
 
     inline void swap(QMutexLocker &other) noexcept
     {
         qt_ptr_swap(m_mutex, other.m_mutex);
         std::swap(m_isLocked, other.m_isLocked);
     }
 
     Mutex *mutex() const
     {
         return m_mutex;
     }
 private:
     Q_DISABLE_COPY(QMutexLocker)
 
     Mutex *m_mutex;
     bool m_isLocked = false;
 };
 
 #else // !QT_CONFIG(thread) && !Q_QDOC
 
 class QMutex
 {
 public:
 
     constexpr QMutex() noexcept { }
 
     inline void lock() noexcept {}
     inline bool tryLock(int timeout = 0) noexcept { Q_UNUSED(timeout); return true; }
     inline bool try_lock() noexcept { return true; }
     inline void unlock() noexcept {}
 
     template <class Rep, class Period>
     inline bool try_lock_for(std::chrono::duration<Rep, Period> duration) noexcept
     {
         Q_UNUSED(duration);
         return true;
     }
 
     template<class Clock, class Duration>
     inline bool try_lock_until(std::chrono::time_point<Clock, Duration> timePoint) noexcept
     {
         Q_UNUSED(timePoint);
         return true;
     }
 
 private:
     Q_DISABLE_COPY(QMutex)
 };
 
 class QRecursiveMutex : public QMutex {};
 
 template <typename Mutex>
 class QMutexLocker
 {
 public:
     Q_NODISCARD_CTOR
     inline explicit QMutexLocker(Mutex *) noexcept {}
     inline ~QMutexLocker() noexcept {}
 
     inline void unlock() noexcept {}
     void relock() noexcept {}
     inline Mutex *mutex() const noexcept { return nullptr; }
 
 private:
     Q_DISABLE_COPY(QMutexLocker)
 };
 
 typedef QMutex QBasicMutex;
 
 #endif // !QT_CONFIG(thread) && !Q_QDOC
 
 QT_END_NAMESPACE
 
 #endif // QMUTEX_H

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