RootConfigParamHelpers.h

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
#ifndef O2_FRAMEWORK_ROOTCONFIGPARAMHELPERS_H_
#define O2_FRAMEWORK_ROOTCONFIGPARAMHELPERS_H_
 
#include "Framework/ConfigParamSpec.h"
#include "Framework/RuntimeError.h"
#include <TClass.h>
#include <boost/property_tree/ptree_fwd.hpp>
#include <type_traits>
#include <typeinfo>
 
namespace o2::framework
{
 
struct RootConfigParamHelpers {
  static std::vector<ConfigParamSpec> asConfigParamSpecsImpl(std::string const& mainkey, TClass* cl, void* obj);
  static void fillFromPtree(TClass* cl, void* obj, boost::property_tree::ptree const& pt);
 
  // Grab the list of data members of a type T and construct the list of
  // associated ConfigParamSpec. Optionally provide a prototype object @a proto
  // to use for the defaults.
  template <typename T>
  static std::vector<ConfigParamSpec> asConfigParamSpecs(std::string const& mainKey, T const& proto = T{})
  {
    auto cl = TClass::GetClass<T>();
    if (!cl) {
      throw runtime_error_f("Unable to convert object %s", typeid(T).name());
    }
 
    return asConfigParamSpecsImpl(mainKey, cl, reinterpret_cast<void*>(const_cast<T*>(&proto)));
  }
 
  template <typename T>
  static T as(boost::property_tree::ptree const& pt)
  {
    T obj;
    TClass* cl = TClass::GetClass<T>();
    fillFromPtree(cl, reinterpret_cast<void*>(&obj), pt);
    return obj;
  }
};
 
} // namespace o2::framework
 
#endif /* O2_FRAMEWORK_ROOTCONFIGPARAMHELPERS_H_ */