jsonwrap.hpp

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/*
 * This file is part of libkazv.
 * SPDX-FileCopyrightText: 2020-2021 Tusooa Zhu <tusooa@kazv.moe>
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */
 
 
#pragma once
#include "libkazv-config.hpp"
 
#include <boost/serialization/version.hpp>
#include <boost/serialization/string.hpp>
#include <boost/serialization/split_member.hpp>
 
#include <nlohmann/json.hpp>
#include <immer/box.hpp>
 
namespace Kazv
{
    using json = nlohmann::json;
 
    class JsonWrap
    {
        // Cannot directly use box here, because it causes the resulting json
        // to be wrapped into an array.
        // https://github.com/arximboldi/immer/issues/155
        struct Private
        {
            json j;
            friend bool operator==(const Private &a, const Private &b) = default;
            friend bool operator!=(const Private &a, const Private &b) = default;
        };
 
        immer::box<Private> m_d;
    public:
        JsonWrap() : m_d(Private{json()}) {}
        JsonWrap(json&& j) : m_d(Private{std::move(j)}) {}
        JsonWrap(const json& j) : m_d(Private{j}) {}
 
        const json &get() const { return m_d.get().j; }
        operator json() const { return m_d.get().j; }
 
        template <class Archive>
        void save(Archive &ar, std::uint32_t const /*version*/) const {
            ar << get().dump();
        }
 
        template <class Archive>
        void load(Archive &ar, std::uint32_t const /*version*/) {
            std::string j;
            ar >> j;
            m_d = immer::box<Private>(Private{json::parse(std::move(j))});
        }
        BOOST_SERIALIZATION_SPLIT_MEMBER()
        friend bool operator==(const JsonWrap &a, const JsonWrap &b) = default;
        friend bool operator!=(const JsonWrap &a, const JsonWrap &b) = default;
    };
}
 
BOOST_CLASS_VERSION(Kazv::JsonWrap, 0)
 
namespace nlohmann
{
    template <>
    struct adl_serializer<Kazv::JsonWrap> {
        static void to_json(json& j, Kazv::JsonWrap w) {
            j = w.get();
        }
 
        static void from_json(const json& j, Kazv::JsonWrap &w) {
            w = Kazv::JsonWrap(j);
        }
    };
}