| /**************************************************************************** |
| ** |
| ** Copyright (C) 2015 The Qt Company Ltd. |
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| ** This file is part of the QtCore module of the Qt Toolkit. |
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| ** $QT_BEGIN_LICENSE:LGPL21$ |
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| |
| #ifndef QREFCOUNT_H |
| #define QREFCOUNT_H |
| |
| #include <QtCore/qatomic.h> |
| |
| QT_BEGIN_NAMESPACE |
| |
| |
| namespace QtPrivate |
| { |
| |
| class RefCount |
| { |
| public: |
| inline bool ref() Q_DECL_NOTHROW { |
| int count = atomic.load(); |
| #if QT_SUPPORTS(UNSHARABLE_CONTAINERS) |
| if (count == 0) // !isSharable |
| return false; |
| #endif |
| if (count != -1) // !isStatic |
| atomic.ref(); |
| return true; |
| } |
| |
| inline bool deref() Q_DECL_NOTHROW { |
| int count = atomic.load(); |
| #if QT_SUPPORTS(UNSHARABLE_CONTAINERS) |
| if (count == 0) // !isSharable |
| return false; |
| #endif |
| if (count == -1) // isStatic |
| return true; |
| return atomic.deref(); |
| } |
| |
| #if QT_SUPPORTS(UNSHARABLE_CONTAINERS) |
| bool setSharable(bool sharable) Q_DECL_NOTHROW |
| { |
| Q_ASSERT(!isShared()); |
| if (sharable) |
| return atomic.testAndSetRelaxed(0, 1); |
| else |
| return atomic.testAndSetRelaxed(1, 0); |
| } |
| |
| bool isSharable() const Q_DECL_NOTHROW |
| { |
| // Sharable === Shared ownership. |
| return atomic.load() != 0; |
| } |
| #endif |
| |
| bool isStatic() const Q_DECL_NOTHROW |
| { |
| // Persistent object, never deleted |
| return atomic.load() == -1; |
| } |
| |
| bool isShared() const Q_DECL_NOTHROW |
| { |
| int count = atomic.load(); |
| return (count != 1) && (count != 0); |
| } |
| |
| void initializeOwned() Q_DECL_NOTHROW { atomic.store(1); } |
| void initializeUnsharable() Q_DECL_NOTHROW { atomic.store(0); } |
| |
| QBasicAtomicInt atomic; |
| }; |
| |
| } |
| |
| #define Q_REFCOUNT_INITIALIZE_STATIC { Q_BASIC_ATOMIC_INITIALIZER(-1) } |
| |
| QT_END_NAMESPACE |
| |
| #endif |