include/QtCore/qthreadstorage.h

0001 // Copyright (C) 2016 The Qt Company Ltd.
0002 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
0003
0004 #ifndef QTHREADSTORAGE_H
0005 #define QTHREADSTORAGE_H
0006
0007 #include <QtCore/qglobal.h>
0008
0009 #if !QT_CONFIG(thread)
0010 #include <memory>
0011 #endif
0012
0013 QT_BEGIN_NAMESPACE
0014
0015 #if QT_CONFIG(thread)
0016
0017 class Q_CORE_EXPORT QThreadStorageData
0018 {
0019 public:
0020     explicit QThreadStorageData(void (*func)(void *));
0021     ~QThreadStorageData();
0022
0023     void** get() const;
0024     void** set(void* p);
0025
0026     static void finish(void**);
0027     int id;
0028 };
0029
0030 // pointer specialization
0031 template <typename T>
0032 inline
0033 T *&qThreadStorage_localData(QThreadStorageData &d, T **)
0034 {
0035     void **v = d.get();
0036     if (!v) v = d.set(nullptr);
0037     return *(reinterpret_cast<T**>(v));
0038 }
0039
0040 template <typename T>
0041 inline
0042 T *qThreadStorage_localData_const(const QThreadStorageData &d, T **)
0043 {
0044     void **v = d.get();
0045     return v ? *(reinterpret_cast<T**>(v)) : 0;
0046 }
0047
0048 template <typename T>
0049 inline
0050 void qThreadStorage_setLocalData(QThreadStorageData &d, T **t)
0051 { (void) d.set(*t); }
0052
0053 template <typename T>
0054 inline
0055 void qThreadStorage_deleteData(void *d, T **)
0056 { delete static_cast<T *>(d); }
0057
0058 // value-based specialization
0059 template <typename T>
0060 inline
0061 T &qThreadStorage_localData(QThreadStorageData &d, T *)
0062 {
0063     void **v = d.get();
0064     if (!v) v = d.set(new T());
0065     return *(reinterpret_cast<T*>(*v));
0066 }
0067
0068 template <typename T>
0069 inline
0070 T qThreadStorage_localData_const(const QThreadStorageData &d, T *)
0071 {
0072     void **v = d.get();
0073     return v ? *(reinterpret_cast<T*>(*v)) : T();
0074 }
0075
0076 template <typename T>
0077 inline
0078 void qThreadStorage_setLocalData(QThreadStorageData &d, T *t)
0079 { (void) d.set(new T(*t)); }
0080
0081 template <typename T>
0082 inline
0083 void qThreadStorage_deleteData(void *d, T *)
0084 { delete static_cast<T *>(d); }
0085
0086 template <class T>
0087 class QThreadStorage
0088 {
0089 private:
0090     QThreadStorageData d;
0091
0092     Q_DISABLE_COPY(QThreadStorage)
0093
0094     static inline void deleteData(void *x)
0095     { qThreadStorage_deleteData(x, reinterpret_cast<T*>(0)); }
0096
0097 public:
0098     inline QThreadStorage() : d(deleteData) { }
0099     inline ~QThreadStorage() { }
0100
0101     inline bool hasLocalData() const
0102     { return d.get() != nullptr; }
0103
0104     inline T& localData()
0105     { return qThreadStorage_localData(d, reinterpret_cast<T*>(0)); }
0106     inline T localData() const
0107     { return qThreadStorage_localData_const(d, reinterpret_cast<T*>(0)); }
0108
0109     inline void setLocalData(T t)
0110     { qThreadStorage_setLocalData(d, &t); }
0111 };
0112
0113 #else // !QT_CONFIG(thread)
0114
0115 template <typename T, typename U>
0116 inline bool qThreadStorage_hasLocalData(const std::unique_ptr<T, U> &data)
0117 {
0118     return !!data;
0119 }
0120
0121 template <typename T, typename U>
0122 inline bool qThreadStorage_hasLocalData(const std::unique_ptr<T*, U> &data)
0123 {
0124     return !!data ? *data != nullptr : false;
0125 }
0126
0127 template <typename T>
0128 inline void qThreadStorage_deleteLocalData(T *t)
0129 {
0130     delete t;
0131 }
0132
0133 template <typename T>
0134 inline void qThreadStorage_deleteLocalData(T **t)
0135 {
0136     delete *t;
0137     delete t;
0138 }
0139
0140 template <class T>
0141 class QThreadStorage
0142 {
0143 private:
0144     struct ScopedPointerThreadStorageDeleter
0145     {
0146         void operator()(T *t) const noexcept
0147         {
0148             if (t == nullptr)
0149                 return;
0150             qThreadStorage_deleteLocalData(t);
0151         }
0152     };
0153     std::unique_ptr<T, ScopedPointerThreadStorageDeleter> data;
0154
0155 public:
0156     QThreadStorage() = default;
0157     ~QThreadStorage() = default;
0158     QThreadStorage(const QThreadStorage &rhs) = delete;
0159     QThreadStorage &operator=(const QThreadStorage &rhs) = delete;
0160
0161     inline bool hasLocalData() const
0162     {
0163         return qThreadStorage_hasLocalData(data);
0164     }
0165
0166     inline T &localData()
0167     {
0168         if (!data)
0169             data.reset(new T());
0170         return *data;
0171     }
0172
0173     inline T localData() const
0174     {
0175         return !!data ? *data : T();
0176     }
0177
0178     inline void setLocalData(T t)
0179     {
0180         data.reset(new T(t));
0181     }
0182 };
0183
0184 #endif // QT_CONFIG(thread)
0185
0186 QT_END_NAMESPACE
0187
0188 #endif // QTHREADSTORAGE_H