| /**************************************************************************** |
| ** |
| ** Copyright (C) 2016 The Qt Company Ltd. |
| ** Copyright (C) 2016 Intel Corporation. |
| ** Copyright (C) 2012 Olivier Goffart <ogoffart@woboq.com> |
| ** Contact: https://www.qt.io/licensing/ |
| ** |
| ** This file is part of the QtCore module of the Qt Toolkit. |
| ** |
| ** $QT_BEGIN_LICENSE:LGPL$ |
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| ** packaging of this file. Please review the following information to |
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| ** |
| ** GNU General Public License Usage |
| ** Alternatively, this file may be used under the terms of the GNU |
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| ****************************************************************************/ |
| |
| #ifndef QMUTEX_P_H |
| #define QMUTEX_P_H |
| |
| // |
| // W A R N I N G |
| // ------------- |
| // |
| // This file is not part of the Qt API. It exists for the convenience |
| // of qmutex.cpp, qmutex_unix.cpp, and qmutex_win.cpp. This header |
| // file may change from version to version without notice, or even be |
| // removed. |
| // |
| // We mean it. |
| // |
| |
| #include <QtCore/private/qglobal_p.h> |
| #include <QtCore/qnamespace.h> |
| #include <QtCore/qmutex.h> |
| #include <QtCore/qatomic.h> |
| #include <QtCore/qdeadlinetimer.h> |
| |
| #if defined(Q_OS_MAC) |
| # include <mach/semaphore.h> |
| #elif defined(Q_OS_LINUX) && !defined(QT_LINUXBASE) |
| // use Linux mutexes everywhere except for LSB builds |
| # define QT_LINUX_FUTEX |
| #elif defined(Q_OS_UNIX) |
| # if _POSIX_VERSION-0 >= 200112L || _XOPEN_VERSION-0 >= 600 |
| # include <semaphore.h> |
| # define QT_UNIX_SEMAPHORE |
| # endif |
| #endif |
| |
| struct timespec; |
| |
| QT_BEGIN_NAMESPACE |
| |
| class QMutexData |
| { |
| public: |
| bool recursive; |
| QMutexData(QMutex::RecursionMode mode = QMutex::NonRecursive) |
| : recursive(mode == QMutex::Recursive) {} |
| }; |
| |
| #if !defined(QT_LINUX_FUTEX) |
| class QMutexPrivate : public QMutexData |
| { |
| public: |
| ~QMutexPrivate(); |
| QMutexPrivate(); |
| |
| bool wait(int timeout = -1); |
| void wakeUp() noexcept; |
| |
| // Control the lifetime of the privates |
| QAtomicInt refCount; |
| int id; |
| |
| bool ref() { |
| Q_ASSERT(refCount.loadRelaxed() >= 0); |
| int c; |
| do { |
| c = refCount.loadRelaxed(); |
| if (c == 0) |
| return false; |
| } while (!refCount.testAndSetRelaxed(c, c + 1)); |
| Q_ASSERT(refCount.loadRelaxed() >= 0); |
| return true; |
| } |
| void deref() { |
| Q_ASSERT(refCount.loadRelaxed() >= 0); |
| if (!refCount.deref()) |
| release(); |
| Q_ASSERT(refCount.loadRelaxed() >= 0); |
| } |
| void release(); |
| static QMutexPrivate *allocate(); |
| |
| QAtomicInt waiters; // Number of threads waiting on this mutex. (may be offset by -BigNumber) |
| QAtomicInt possiblyUnlocked; /* Boolean indicating that a timed wait timed out. |
| When it is true, a reference is held. |
| It is there to avoid a race that happens if unlock happens right |
| when the mutex is unlocked. |
| */ |
| enum { BigNumber = 0x100000 }; //Must be bigger than the possible number of waiters (number of threads) |
| void derefWaiters(int value) noexcept; |
| |
| //platform specific stuff |
| #if defined(Q_OS_MAC) |
| semaphore_t mach_semaphore; |
| #elif defined(QT_UNIX_SEMAPHORE) |
| sem_t semaphore; |
| #elif defined(Q_OS_UNIX) |
| bool wakeup; |
| pthread_mutex_t mutex; |
| pthread_cond_t cond; |
| #elif defined(Q_OS_WIN) |
| Qt::HANDLE event; |
| #endif |
| }; |
| #endif //QT_LINUX_FUTEX |
| |
| |
| #ifdef Q_OS_UNIX |
| // helper functions for qmutex_unix.cpp and qwaitcondition_unix.cpp |
| // they are in qwaitcondition_unix.cpp actually |
| void qt_initialize_pthread_cond(pthread_cond_t *cond, const char *where); |
| void qt_abstime_for_timeout(struct timespec *ts, QDeadlineTimer deadline); |
| #endif |
| |
| QT_END_NAMESPACE |
| |
| #endif // QMUTEX_P_H |