view_or_value.hpp

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// Copyright 2009-present MongoDB, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#pragma once
 
#include <type_traits>
 
#include <bsoncxx/view_or_value-fwd.hpp>
 
#include <bsoncxx/stdx/optional.hpp>
 
#include <bsoncxx/config/prelude.hpp>
 
namespace bsoncxx {
namespace v_noabi {

template <typename View, typename Value>
class view_or_value {
   public:
    using view_type = View;
    using value_type = Value;

    static_assert(std::is_constructible<View, Value>::value, "View type must be constructible from a Value");

    static_assert(std::is_default_constructible<View>::value, "View type must be default constructible");

    ~view_or_value() = default;

    view_or_value() = default;

    view_or_value(View view) : _view{view} {}

    view_or_value(Value&& value) : _value(std::move(value)), _view(*_value) {}

    view_or_value(view_or_value const& other) : _value(other._value), _view(_value ? *_value : other._view) {}

    view_or_value& operator=(view_or_value const& other) {
        _value = other._value;
        _view = _value ? *_value : other._view;
        return *this;
    }
    view_or_value& operator=(view_or_value const& other) {…}


    view_or_value(view_or_value&& other) noexcept
        : _value{std::move(other._value)}, _view(_value ? *_value : std::move(other._view)) {
        other._view = View();
        other._value = stdx::nullopt;
    }
    view_or_value(view_or_value&& other) noexcept {…}

    view_or_value& operator=(view_or_value&& other) noexcept {
        _value = std::move(other._value);
        _view = _value ? *_value : std::move(other._view);
        other._view = View();
        other._value = stdx::nullopt;
        return *this;
    }
    view_or_value& operator=(view_or_value&& other) noexcept {…}

    bool is_owning() const noexcept {
        return static_cast<bool>(_value);
    }
    bool is_owning() const noexcept {…}

    operator View() const {
        return _view;
    }
    operator View() const  {…}

    View const& view() const {
        return _view;
    }
    View const& view() const  {…}
 
   private:
    stdx::optional<Value> _value;
    View _view;
};
class view_or_value {…};


template <typename View, typename Value>
bool operator==(view_or_value<View, Value> const& lhs, view_or_value<View, Value> const& rhs) {
    return lhs.view() == rhs.view();
}
bool operator==(view_or_value<View, Value> const& lhs, view_or_value<View, Value> const& rhs) {…}

template <typename View, typename Value>
bool operator!=(view_or_value<View, Value> const& lhs, view_or_value<View, Value> const& rhs) {
    return !(lhs == rhs);
}
bool operator!=(view_or_value<View, Value> const& lhs, view_or_value<View, Value> const& rhs) {…}



template <typename View, typename Value>
bool operator==(view_or_value<View, Value> const& lhs, View rhs) {
    return lhs.view() == rhs;
}
bool operator==(view_or_value<View, Value> const& lhs, View rhs) {…}

template <typename View, typename Value>
bool operator==(View lhs, view_or_value<View, Value> const& rhs) {
    return rhs == lhs;
}
bool operator==(View lhs, view_or_value<View, Value> const& rhs) {…}

template <typename View, typename Value>
bool operator!=(view_or_value<View, Value> const& lhs, View rhs) {
    return !(lhs == rhs);
}
bool operator!=(view_or_value<View, Value> const& lhs, View rhs) {…}

template <typename View, typename Value>
bool operator!=(View lhs, view_or_value<View, Value> const& rhs) {
    return !(rhs == lhs);
}
bool operator!=(View lhs, view_or_value<View, Value> const& rhs) {…}

template <typename View, typename Value>
bool operator==(view_or_value<View, Value> const& lhs, Value const& rhs) {
    return lhs.view() == View(rhs);
}
bool operator==(view_or_value<View, Value> const& lhs, Value const& rhs) {…}

template <typename View, typename Value>
bool operator==(Value const& lhs, view_or_value<View, Value> const& rhs) {
    return rhs == lhs;
}
bool operator==(Value const& lhs, view_or_value<View, Value> const& rhs) {…}

template <typename View, typename Value>
bool operator!=(view_or_value<View, Value> const& lhs, Value const& rhs) {
    return !(lhs == rhs);
}
bool operator!=(view_or_value<View, Value> const& lhs, Value const& rhs) {…}

template <typename View, typename Value>
bool operator!=(Value const& lhs, view_or_value<View, Value> const& rhs) {
    return !(rhs == lhs);
}
bool operator!=(Value const& lhs, view_or_value<View, Value> const& rhs) {…}

 
} // namespace v_noabi
} // namespace bsoncxx
 
namespace bsoncxx {
 
using ::bsoncxx::v_noabi::operator==;
using ::bsoncxx::v_noabi::operator!=;
 
} // namespace bsoncxx
 
#include <bsoncxx/config/postlude.hpp>