signal.h

/********************************************************************
 * Copyright (C) 2015 Liangliang Nan <liangliang.nan@gmail.com>
 * https://3d.bk.tudelft.nl/liangliang/
 *
 * This file is part of Easy3D. If it is useful in your research/work,
 * I would be grateful if you show your appreciation by citing it:
 * ------------------------------------------------------------------
 *      Liangliang Nan.
 *      Easy3D: a lightweight, easy-to-use, and efficient C++ library
 *      for processing and rendering 3D data.
 *      Journal of Open Source Software, 6(64), 3255, 2021.
 * ------------------------------------------------------------------
 *
 * Easy3D is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License Version 3
 * as published by the Free Software Foundation.
 *
 * Easy3D 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 ********************************************************************/
 
#ifndef EASY3D_UTIL_SIGNAL_H
#define EASY3D_UTIL_SIGNAL_H
 
 
#include <functional>
#include <unordered_map>
 
 
namespace easy3d {

 
    template<typename... Args>
    class Signal {
 
    public:
        Signal() = default;
        ~Signal() { disconnect_all(); }

        Signal(Signal const & /*unused*/) {}

        Signal(Signal &&other) noexcept:
                slots_(std::move(other.slots_)),
                current_id_(other.current_id_) {
        }

        Signal &operator=(Signal &&other) noexcept {
            if (this != &other) {
                slots_ = std::move(other.slots_);
                current_id_ = other.current_id_;
            }
            return *this;
        }

        Signal &operator=(Signal const &other) {
            if (this != &other) {
                disconnect_all();
            }
            return *this;
        }

        int connect(std::function<void(Args...)> const &slot) {
            slots_.insert(std::make_pair(++current_id_, slot));
            return current_id_;
        }

        template<typename Class>
        int connect(Class *inst, void (Class::*func)(Args...)) {
            return connect([=](Args... args) {
                (inst->*func)(args...);
            });
        }

        template<typename Class>
        int connect(Class *inst, void (Class::*func)(Args...) const) {
            return connect([=](Args... args) {
                (inst->*func)(args...);
            });
        }

        int connect(Signal<Args...> *receiver) {
            return connect(receiver, &Signal<Args...>::send);
        }

        void disconnect(int id) {
            slots_.erase(id);
        }

        void disconnect_all() {
            slots_.clear();
        }

        void send(Args... p) {
            for (auto const &it : slots_) {
                it.second(p...);
            }
        }

        void send_for_all_but_one(int excludedConnectionID, Args... p) {
            for (auto const &it : slots_) {
                if (it.first != excludedConnectionID) {
                    it.second(p...);
                }
            }
        }

        void emit_for(int connectionID, Args... p) {
            auto const &it = slots_.find(connectionID);
            if (it != slots_.end()) {
                it->second(p...);
            }
        }
 
    private:
        std::unordered_map<int, std::function<void(Args...)>> slots_;
        int current_id_{0};
    };
 



    template<typename SIGNAL, typename FUNCTION>
    inline int connect(SIGNAL *signal, FUNCTION const &slot) {
        return signal->connect(slot);
    }

    template<typename SIGNAL, typename CLASS, typename FUNCTION>
    inline int connect(SIGNAL *signal, CLASS *inst, FUNCTION const &slot) {
        return signal->connect(inst, slot);
    }

    template<typename... Args>
    int connect(Signal<Args...> *sender, Signal<Args...> *receiver) {
        return sender->connect(receiver);
    }

    template<typename SIGNAL>
    inline void disconnect(SIGNAL *signal, int id) {
        signal->disconnect(id);
    }

    template<typename SIGNAL>
    inline void disconnect_all(SIGNAL *signal) {
        signal->disconnect_all();
    }




    template <typename... Args>
    inline constexpr auto overload(void (*func)(Args...)) -> void (*)(Args...) {
        return func;
    }

    template <typename C, typename... Args>
    inline constexpr auto overload(void (C::*func)(Args...)) -> void (C::*)(Args...) {
        return func;
    }

 



}
 
 
#endif // EASY3D_UTIL_SIGNAL_H