corecel/io/JsonPimpl.hh

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