| 1 | // Copyright (C) 2018 The Qt Company Ltd. |
|---|---|
| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only |
| 3 | |
| 4 | #pragma once |
| 5 | |
| 6 | #include <QtCore/qglobal.h> |
| 7 | #include <QtQml/private/qtqmlglobal_p.h> |
| 8 | |
| 9 | #include <memory> |
| 10 | #if __cplusplus > 201402L && __has_include(<optional>) |
| 11 | #include <optional> |
| 12 | #else |
| 13 | |
| 14 | namespace std { |
| 15 | |
| 16 | struct nullopt_t {}; |
| 17 | |
| 18 | constexpr nullopt_t nullopt {}; |
| 19 | |
| 20 | template<typename T> |
| 21 | class optional { |
| 22 | public: |
| 23 | optional() = default; |
| 24 | optional(nullopt_t) {} |
| 25 | optional(const T &v) : _value(v), _hasValue(true) {} |
| 26 | ~optional() = default; |
| 27 | |
| 28 | optional &operator =(nullopt_t) { |
| 29 | _value = T(); |
| 30 | _hasValue = false; |
| 31 | return *this; |
| 32 | } |
| 33 | |
| 34 | T operator->() { return _value; } |
| 35 | T operator*() { return _value; } |
| 36 | |
| 37 | operator bool() const { return _hasValue; } |
| 38 | bool has_value() const { return _hasValue; } |
| 39 | |
| 40 | T value() const { return _value; } |
| 41 | |
| 42 | private: |
| 43 | T _value = T(); |
| 44 | bool _hasValue = false; |
| 45 | }; |
| 46 | |
| 47 | } |
| 48 | |
| 49 | #endif |
| 50 |