| 1 | // Copyright (C) 2020 The Qt Company Ltd. |
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| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only |
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| 3 | |
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| 4 | #ifndef QLAZILYALLOCATED_P_H |
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| 5 | #define QLAZILYALLOCATED_P_H |
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| 6 | |
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| 7 | // |
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| 8 | // W A R N I N G |
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| 9 | // ------------- |
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| 10 | // |
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| 11 | // This file is not part of the Qt API. It exists purely as an |
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| 12 | // implementation detail. This header file may change from version to |
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| 13 | // version without notice, or even be removed. |
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| 14 | // |
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| 15 | // We mean it. |
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| 16 | // |
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| 17 | |
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| 18 | #include <QtCore/private/qglobal_p.h> |
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| 19 | #include <QtCore/qtaggedpointer.h> |
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| 20 | |
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| 21 | QT_BEGIN_NAMESPACE |
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| 22 | |
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| 23 | template<typename T, typename Tag = typename QtPrivate::TagInfo<T>::TagType> |
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| 24 | class QLazilyAllocated { |
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| 25 | public: |
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| 26 | inline QLazilyAllocated(); |
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| 27 | inline ~QLazilyAllocated(); |
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| 28 | |
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| 29 | inline bool isAllocated() const; |
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| 30 | |
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| 31 | inline T *operator->() const; |
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| 32 | |
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| 33 | inline T &value(); |
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| 34 | inline const T &value() const; |
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| 35 | |
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| 36 | inline Tag tag() const; |
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| 37 | inline void setTag(Tag t); |
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| 38 | private: |
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| 39 | mutable QTaggedPointer<T, Tag> d; |
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| 40 | }; |
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| 41 | |
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| 42 | template<typename T, typename Tag> |
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| 43 | QLazilyAllocated<T, Tag>::QLazilyAllocated() |
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| 44 | { |
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| 45 | } |
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| 46 | |
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| 47 | template<typename T, typename Tag> |
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| 48 | QLazilyAllocated<T, Tag>::~QLazilyAllocated() |
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| 49 | { |
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| 50 | delete d.data(); |
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| 51 | } |
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| 52 | |
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| 53 | template<typename T, typename Tag> |
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| 54 | bool QLazilyAllocated<T, Tag>::isAllocated() const |
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| 55 | { |
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| 56 | return !d.isNull(); |
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| 57 | } |
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| 58 | |
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| 59 | template<typename T, typename Tag> |
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| 60 | T &QLazilyAllocated<T, Tag>::value() |
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| 61 | { |
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| 62 | if (d.isNull()) d = new T; |
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| 63 | return *d; |
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| 64 | } |
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| 65 | |
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| 66 | template<typename T, typename Tag> |
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| 67 | const T &QLazilyAllocated<T, Tag>::value() const |
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| 68 | { |
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| 69 | if (d.isNull()) d = new T; |
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| 70 | return *d; |
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| 71 | } |
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| 72 | |
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| 73 | template<typename T, typename Tag> |
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| 74 | T *QLazilyAllocated<T, Tag>::operator->() const |
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| 75 | { |
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| 76 | return d.data(); |
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| 77 | } |
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| 78 | |
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| 79 | template<typename T, typename Tag> |
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| 80 | Tag QLazilyAllocated<T, Tag>::tag() const |
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| 81 | { |
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| 82 | return d.tag(); |
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| 83 | } |
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| 84 | |
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| 85 | template<typename T, typename Tag> |
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| 86 | void QLazilyAllocated<T, Tag>::setTag(Tag t) |
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| 87 | { |
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| 88 | d.setTag(t); |
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| 89 | } |
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| 90 | |
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| 91 | QT_END_NAMESPACE |
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| 92 | |
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| 93 | #endif // QLAZILYALLOCATED_P_H |
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| 94 | |
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