corecel/io/JsonPimpl.hh

0001 //----------------------------------*-C++-*----------------------------------//
0002 // Copyright 2022-2024 UT-Battelle, LLC, and other Celeritas developers.
0003 // See the top-level COPYRIGHT file for details.
0004 // SPDX-License-Identifier: (Apache-2.0 OR MIT)
0005 //---------------------------------------------------------------------------//
0006 //! \file corecel/io/JsonPimpl.hh
0007 //---------------------------------------------------------------------------//
0008 #pragma once
0009
0010 #include <nlohmann/json.hpp>
0011
0012 #include "corecel/Config.hh"
0013
0014 #include "corecel/Assert.hh"
0015
0016 namespace celeritas
0017 {
0018 //---------------------------------------------------------------------------//
0019 /*!
0020  * Wrapper class for exporting JSON output.
0021  *
0022  * The caller is expected to use the value directly, so replace \c obj with the
0023  * JSON object.
0024  *
0025  * \code
0026     void output(JsonPimpl* json) const
0027     {
0028         json->obj = value_;
0029     }
0030  * \endcode
0031  */
0032 struct JsonPimpl
0033 {
0034     nlohmann::json obj;
0035 };
0036
0037 //---------------------------------------------------------------------------//
0038 /*!
0039  * Helper function to write an object to JSON.
0040  *
0041  * This hides the "not configured" boilerplate.
0042  */
0043 template<class T>
0044 void to_json_pimpl(JsonPimpl* jp, T const& self)
0045 {
0046     CELER_EXPECT(jp);
0047     to_json(jp->obj, self);
0048 }
0049
0050 template<class T>
0051 nlohmann::json json_pimpl_output(T const& self)
0052 {
0053     JsonPimpl jp;
0054     self.output(&jp);
0055     return std::move(jp.obj);
0056 }
0057
0058 //---------------------------------------------------------------------------//
0059 }  // namespace celeritas