CheckTypes.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_CHECKTYPES_H_
#define O2_FRAMEWORK_CHECKTYPES_H_
 
#include <algorithm>
#include <type_traits>
#include "CompilerBuiltins.h"
 
namespace o2::framework
{
 
template <typename, typename = void>
constexpr bool is_type_complete_v = false;
 
template <typename T>
constexpr bool is_type_complete_v<T, std::void_t<decltype(sizeof(T))>> = true;
 
template <typename T, typename TDefined, typename TUndefined>
void call_if_defined_full(TDefined&& onDefined, TUndefined&& onUndefined)
{
  if constexpr (is_type_complete_v<T>) {
    onDefined(static_cast<T*>(nullptr));
  } else {
    onUndefined();
  }
}
 
template <typename T, typename TDefined, typename TUndefined>
T call_if_defined_full_forward(TDefined&& onDefined, TUndefined&& onUndefined)
{
  if constexpr (is_type_complete_v<T>) {
    return std::move(onDefined(static_cast<T*>(nullptr)));
  } else {
    return onUndefined();
  }
}
 
template <typename T, typename TDefined>
void call_if_defined(TDefined&& onDefined)
{
  call_if_defined_full<T>(onDefined, []() -> void {});
}
 
template <typename T, typename TDefined>
T call_if_defined_forward(TDefined&& onDefined)
{
  return std::move(call_if_defined_full_forward<T>(onDefined, []() -> T&& { O2_BUILTIN_UNREACHABLE(); }));
}
 
} // namespace o2::framework
 
#endif // O2_FRAMEWORK_CHECKTYPES_H_