| 1 | /**************************************************************************** |
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| 2 | ** |
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| 3 | ** Copyright (C) 2018 The Qt Company Ltd. |
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| 4 | ** Contact: https://www.qt.io/licensing/ |
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| 5 | ** |
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| 6 | ** This file is part of the QtQml module of the Qt Toolkit. |
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| 7 | ** |
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| 8 | ** $QT_BEGIN_LICENSE:LGPL$ |
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| 9 | ** Commercial License Usage |
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| 10 | ** Licensees holding valid commercial Qt licenses may use this file in |
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| 11 | ** accordance with the commercial license agreement provided with the |
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| 12 | ** Software or, alternatively, in accordance with the terms contained in |
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| 13 | ** a written agreement between you and The Qt Company. For licensing terms |
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| 14 | ** and conditions see https://www.qt.io/terms-conditions. For further |
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| 15 | ** information use the contact form at https://www.qt.io/contact-us. |
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| 16 | ** |
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| 17 | ** GNU Lesser General Public License Usage |
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| 18 | ** Alternatively, this file may be used under the terms of the GNU Lesser |
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| 19 | ** General Public License version 3 as published by the Free Software |
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| 20 | ** Foundation and appearing in the file LICENSE.LGPL3 included in the |
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| 21 | ** packaging of this file. Please review the following information to |
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| 22 | ** ensure the GNU Lesser General Public License version 3 requirements |
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| 23 | ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. |
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| 24 | ** |
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| 25 | ** GNU General Public License Usage |
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| 26 | ** Alternatively, this file may be used under the terms of the GNU |
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| 27 | ** General Public License version 2.0 or (at your option) the GNU General |
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| 28 | ** Public license version 3 or any later version approved by the KDE Free |
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| 29 | ** Qt Foundation. The licenses are as published by the Free Software |
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| 30 | ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 |
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| 31 | ** included in the packaging of this file. Please review the following |
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| 32 | ** information to ensure the GNU General Public License requirements will |
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| 33 | ** be met: https://www.gnu.org/licenses/gpl-2.0.html and |
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| 34 | ** https://www.gnu.org/licenses/gpl-3.0.html. |
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| 35 | ** |
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| 36 | ** $QT_END_LICENSE$ |
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| 37 | ** |
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| 38 | ****************************************************************************/ |
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| 39 | |
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| 40 | #pragma once |
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| 41 | |
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| 42 | #include <QtCore/qglobal.h> |
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| 43 | #include <QtQml/private/qtqmlglobal_p.h> |
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| 44 | |
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| 45 | #include <memory> |
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| 46 | #if __cplusplus > 201402L && __has_include(<optional>) |
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| 47 | #include <optional> |
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| 48 | #else |
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| 49 | |
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| 50 | namespace std { |
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| 51 | |
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| 52 | struct nullopt_t {}; |
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| 53 | |
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| 54 | constexpr nullopt_t nullopt {}; |
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| 55 | |
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| 56 | template<typename T> |
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| 57 | class optional { |
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| 58 | public: |
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| 59 | optional() = default; |
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| 60 | optional(nullopt_t) {} |
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| 61 | optional(const T &v) : _value(v), _hasValue(true) {} |
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| 62 | ~optional() = default; |
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| 63 | |
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| 64 | optional &operator =(nullopt_t) { |
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| 65 | _value = T(); |
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| 66 | _hasValue = false; |
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| 67 | return *this; |
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| 68 | } |
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| 69 | |
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| 70 | T operator->() { return _value; } |
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| 71 | T operator*() { return _value; } |
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| 72 | |
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| 73 | operator bool() const { return _hasValue; } |
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| 74 | bool has_value() const { return _hasValue; } |
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| 75 | |
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| 76 | T value() const { return _value; } |
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| 77 | |
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| 78 | private: |
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| 79 | T _value = T(); |
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| 80 | bool _hasValue = false; |
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| 81 | }; |
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| 82 | |
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| 83 | } |
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| 84 | |
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| 85 | #endif |
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| 86 | |
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