Optional.h - mozsearch

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// Copyright (C) 2018 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#pragma once

#include <QtCore/qglobal.h>

#include <QtQml/private/qtqmlglobal_p.h>

#include <memory>

#if __cplusplus > 201402L && __has_include(<optional>)

#include <optional>

#else

namespace std {

struct nullopt_t {};

constexpr nullopt_t nullopt {};

template<typename T>

class optional {

public:

    optional() = default;

    optional(nullopt_t) {}

    optional(const T &v) : _value(v), _hasValue(true) {}

    ~optional() = default;

    optional &operator =(nullopt_t) {

        _value = T();

        _hasValue = false;

        return *this;

    T operator->() { return _value; }

    T operator*() { return _value; }

    operator bool() const { return _hasValue; }

    bool has_value() const { return _hasValue; }

    T value() const { return _value; }

private:

    T _value = T();

    bool _hasValue = false;

};

#endif