qatomic.h

Go to the documentation of this file.

// Copyright (C) 2017 The Qt Company Ltd.
// Copyright (C) 2016 Intel Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:significant reason:default
 
#ifndef QATOMIC_H
#define QATOMIC_H
 
#include <QtCore/qbasicatomic.h>
 
QT_BEGIN_NAMESPACE
 
QT_WARNING_PUSH
QT_WARNING_DISABLE_GCC("-Wextra")
 
// High-level atomic integer operations
template <typename T>
class QAtomicInteger : public QBasicAtomicInteger<T>
{
public:
    // Non-atomic API
    constexpr QAtomicInteger(T value = 0) noexcept : QBasicAtomicInteger<T>(value) {}
 
    inline QAtomicInteger(const QAtomicInteger &other) noexcept
        : QBasicAtomicInteger<T>()
    {
        this->storeRelease(other.loadAcquire());
    }
 
    inline QAtomicInteger &operator=(const QAtomicInteger &other) noexcept
    {
        this->storeRelease(other.loadAcquire());
        return *this;
    }
 
#ifdef Q_QDOC
    T loadRelaxed() const;
    T loadAcquire() const;
    void storeRelaxed(T newValue);
    void storeRelease(T newValue);
 
    operator T() const;
    QAtomicInteger &operator=(T);
 
    static constexpr bool isReferenceCountingNative();
    static constexpr bool isReferenceCountingWaitFree();
 
    bool ref();
    bool deref();
 
    static constexpr bool isTestAndSetNative();
    static constexpr bool isTestAndSetWaitFree();
 
    bool testAndSetRelaxed(T expectedValue, T newValue);
    bool testAndSetAcquire(T expectedValue, T newValue);
    bool testAndSetRelease(T expectedValue, T newValue);
    bool testAndSetOrdered(T expectedValue, T newValue);
 
    bool testAndSetRelaxed(T expectedValue, T newValue, T &currentValue);
    bool testAndSetAcquire(T expectedValue, T newValue, T &currentValue);
    bool testAndSetRelease(T expectedValue, T newValue, T &currentValue);
    bool testAndSetOrdered(T expectedValue, T newValue, T &currentValue);
 
    static constexpr bool isFetchAndStoreNative();
    static constexpr bool isFetchAndStoreWaitFree();
 
    T fetchAndStoreRelaxed(T newValue);
    T fetchAndStoreAcquire(T newValue);
    T fetchAndStoreRelease(T newValue);
    T fetchAndStoreOrdered(T newValue);
 
    static constexpr bool isFetchAndAddNative();
    static constexpr bool isFetchAndAddWaitFree();
 
    T fetchAndAddRelaxed(T valueToAdd);
    T fetchAndAddAcquire(T valueToAdd);
    T fetchAndAddRelease(T valueToAdd);
    T fetchAndAddOrdered(T valueToAdd);
 
    T fetchAndSubRelaxed(T valueToSub);
    T fetchAndSubAcquire(T valueToSub);
    T fetchAndSubRelease(T valueToSub);
    T fetchAndSubOrdered(T valueToSub);
 
    T fetchAndOrRelaxed(T valueToOr);
    T fetchAndOrAcquire(T valueToOr);
    T fetchAndOrRelease(T valueToOr);
    T fetchAndOrOrdered(T valueToOr);
 
    T fetchAndAndRelaxed(T valueToAnd);
    T fetchAndAndAcquire(T valueToAnd);
    T fetchAndAndRelease(T valueToAnd);
    T fetchAndAndOrdered(T valueToAnd);
 
    T fetchAndXorRelaxed(T valueToXor);
    T fetchAndXorAcquire(T valueToXor);
    T fetchAndXorRelease(T valueToXor);
    T fetchAndXorOrdered(T valueToXor);
 
    T operator++();
    T operator++(int);
    T operator--();
    T operator--(int);
    T operator+=(T value);
    T operator-=(T value);
    T operator|=(T value);
    T operator&=(T value);
    T operator^=(T value);
#endif
};
 
class QAtomicInt : public QAtomicInteger<int>
{
public:
    // Non-atomic API
    // We could use QT_COMPILER_INHERITING_CONSTRUCTORS, but we need only one;
    // the implicit definition for all the others is fine.
    constexpr QAtomicInt(int value = 0) noexcept : QAtomicInteger<int>(value) {}
};
 
// High-level atomic pointer operations
template <typename T>
class QAtomicPointer : public QBasicAtomicPointer<T>
{
public:
    constexpr QAtomicPointer(T *value = nullptr) noexcept : QBasicAtomicPointer<T>(value) {}
 
    inline QAtomicPointer(const QAtomicPointer<T> &other) noexcept
        : QBasicAtomicPointer<T>()
    {
        this->storeRelease(other.loadAcquire());
    }
 
    inline QAtomicPointer<T> &operator=(const QAtomicPointer<T> &other) noexcept
    {
        this->storeRelease(other.loadAcquire());
        return *this;
    }
 
#ifdef Q_QDOC
    T *loadAcquire() const;
    T *loadRelaxed() const;
    void storeRelaxed(T *newValue);
    void storeRelease(T *newValue);
 
    static constexpr bool isTestAndSetNative();
    static constexpr bool isTestAndSetWaitFree();
 
    bool testAndSetRelaxed(T *expectedValue, T *newValue);
    bool testAndSetAcquire(T *expectedValue, T *newValue);
    bool testAndSetRelease(T *expectedValue, T *newValue);
    bool testAndSetOrdered(T *expectedValue, T *newValue);
 
    static constexpr bool isFetchAndStoreNative();
    static constexpr bool isFetchAndStoreWaitFree();
 
    T *fetchAndStoreRelaxed(T *newValue);
    T *fetchAndStoreAcquire(T *newValue);
    T *fetchAndStoreRelease(T *newValue);
    T *fetchAndStoreOrdered(T *newValue);
 
    static constexpr bool isFetchAndAddNative();
    static constexpr bool isFetchAndAddWaitFree();
 
    T *fetchAndAddRelaxed(qptrdiff valueToAdd);
    T *fetchAndAddAcquire(qptrdiff valueToAdd);
    T *fetchAndAddRelease(qptrdiff valueToAdd);
    T *fetchAndAddOrdered(qptrdiff valueToAdd);
#endif
};
 
QT_WARNING_POP
 
/*!
    This is a helper for the assignment operators of implicitly
    shared classes. Your assignment operator should look like this:
 
    \snippet code/src.corelib.thread.qatomic.h 0
*/
template <typename T>
inline void qAtomicAssign(T *&d, T *x)
{
    if (d == x)
        return;
    x->ref.ref();
    if (!d->ref.deref())
        delete d;
    d = x;
}
 
/*!
    This is a helper for the detach method of implicitly shared
    classes. Your private class needs a copy constructor which copies
    the members and sets the refcount to 1. After that, your detach
    function should look like this:
 
    \snippet code/src.corelib.thread.qatomic.h 1
*/
template <typename T>
inline void qAtomicDetach(T *&d)
{
    if (d->ref.loadRelaxed() == 1)
        return;
    T *x = d;
    d = new T(*d);
    if (!x->ref.deref())
        delete x;
}
 
QT_END_NAMESPACE
#endif // QATOMIC_H