| /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */ |
| /* |
| * Copyright (c) 2013-2023 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. |
| */ |
| |
| #ifndef NDN_CXX_UTIL_SIGNAL_CONNECTION_HPP |
| #define NDN_CXX_UTIL_SIGNAL_CONNECTION_HPP |
| |
| #include "ndn-cxx/detail/common.hpp" |
| |
| namespace ndn::signal { |
| |
| using DisconnectFunction = std::function<void()>; |
| |
| /** |
| * \brief Represents a connection to a signal. |
| * \note This type is copyable. Any copy can be used to disconnect. |
| */ |
| class Connection |
| { |
| public: |
| constexpr |
| Connection() noexcept = default; |
| |
| /** \brief Disconnects from the signal. |
| * \note If the connection is already disconnected, or if the Signal has been destructed, |
| * this operation has no effect. |
| * \warning During signal emission, attempting to disconnect a connection other than |
| * the executing handler's own connection results in undefined behavior. |
| */ |
| void |
| disconnect(); |
| |
| /** \brief Check if connected to the signal. |
| */ |
| bool |
| isConnected() const noexcept |
| { |
| return !m_disconnect.expired(); |
| } |
| |
| private: |
| /** \param disconnect weak_ptr to a function that disconnects the handler |
| */ |
| explicit |
| Connection(weak_ptr<DisconnectFunction> disconnect) noexcept; |
| |
| template<typename Owner, typename... TArgs> |
| friend class Signal; |
| |
| private: |
| // NOTE: the following "hidden friend" operators are available via |
| // argument-dependent lookup only and must be defined inline. |
| |
| /** \brief Compare for equality. |
| * |
| * Two connections are equal if they both refer to the same connection that isn't disconnected, |
| * or they are both disconnected. |
| */ |
| friend bool |
| operator==(const Connection& lhs, const Connection& rhs) noexcept |
| { |
| return (!lhs.isConnected() && !rhs.isConnected()) || |
| (!lhs.m_disconnect.owner_before(rhs.m_disconnect) && |
| !rhs.m_disconnect.owner_before(lhs.m_disconnect)); |
| } |
| |
| friend bool |
| operator!=(const Connection& lhs, const Connection& rhs) noexcept |
| { |
| return !(lhs == rhs); |
| } |
| |
| private: |
| /** \note The only shared_ptr to the disconnect function is stored in Signal<..>::Slot, |
| * and will be destructed if the handler is disconnected (through another Connection |
| * instance) or the Signal is destructed. |
| * Connection needs a weak_ptr instead of a shared_ptr to the disconnect function, |
| * because the disconnect function is bound with an iterator to the Slot, |
| * which is invalidated when the Slot is erased. |
| */ |
| weak_ptr<DisconnectFunction> m_disconnect; |
| }; |
| |
| } // namespace ndn::signal |
| |
| namespace ndn::util::signal { |
| /// \deprecated Use ndn::signal::Connection |
| using Connection = ::ndn::signal::Connection; |
| } // namespace ndn::util::signal |
| |
| #endif // NDN_CXX_UTIL_SIGNAL_CONNECTION_HPP |