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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2013-2018 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
* ndn-cxx library is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later version.
*
* ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
*
* You should have received copies of the GNU General Public License and GNU Lesser
* General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
* <http://www.gnu.org/licenses/>.
*
* See AUTHORS.md for complete list of ndn-cxx authors and contributors.
*/
/** \file
*
* This header provides macros that allows a signal to be emitted
* from a derived class of its owner.
*
* In 'protected' section of owner class declaration,
* DECLARE_SIGNAL_EMIT(signalName)
* From a derived class of owner,
* this->emitSignal(signalName, arg1, arg2);
*/
#ifndef NDN_UTIL_SIGNAL_EMIT_HPP
#define NDN_UTIL_SIGNAL_EMIT_HPP
namespace ndn {
namespace util {
namespace signal {
/** \brief (implementation detail) a filler for extra argument
*/
class DummyExtraArg
{
};
} // namespace signal
} // namespace util
} // namespace ndn
/** \brief (implementation detail) declares a 'emit_signalName' method
* \note This macro should be used in 'protected' section so that it's accessible
* by derived classes.
* \note emit_signalName method is implementation detail.
* Derived classes should use 'emitSignal' macro.
* \note The name 'emit_signalName' is an intentional violation of code-style rule 2.5.
* \note The method is declared as a template, so that the macro doesn't need argument types.
* But only argument types that are compatible with Signal declaration will work.
*/
#define DECLARE_SIGNAL_EMIT(signalName) \
template<typename ...TArgs> \
void emit_##signalName(const TArgs&... args) \
{ \
signalName(args...); \
}
/** \brief (implementation detail) invokes emit_signalName method
* \note C99 requires at least one argument to be passed in __VA_ARGS__,
* thus a DummyExtraArg is expected at the end of __VA_ARGS__,
* which will be accepted but ignored by Signal::operator() overload.
*/
#define NDN_CXX_SIGNAL_EMIT(signalName, ...) \
emit_##signalName(__VA_ARGS__)
/** \brief (implementation detail)
*/
#define emitSignal(...) \
NDN_CXX_SIGNAL_EMIT(__VA_ARGS__, ::ndn::util::signal::DummyExtraArg())
#endif // NDN_UTIL_SIGNAL_EMIT_HPP