EventMultiplexer.h

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/*
 * SNode.C - a slim toolkit for network communication
 * Copyright (C) Volker Christian <me@vchrist.at>
 *               2020, 2021, 2022, 2023, 2024, 2025
 *
 * This program 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.
 *
 * This program 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 a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef CORE_EVENTMULTIPLEXER_H
#define CORE_EVENTMULTIPLEXER_H
 
#include "core/TickStatus.h"
 
namespace core {
    class Event;
    class DescriptorEventPublisher;
    class TimerEventPublisher;
} // namespace core
 
namespace utils {
    class Timeval;
} // namespace utils
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#include "utils/system/signal.h"
 
#include <array>
#include <list>
 
#endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
namespace core {
 
    class EventMultiplexer {
    public:
        EventMultiplexer(DescriptorEventPublisher* readDescriptorEventPublisher,
                         DescriptorEventPublisher* writeDescriptorEventPublisher,
                         DescriptorEventPublisher* exceptionDescriptorEventPublisher);
        virtual ~EventMultiplexer();
 
        EventMultiplexer(const EventMultiplexer&) = delete;
 
        EventMultiplexer& operator=(const EventMultiplexer&) = delete;
 
    private:
        class EventQueue {
        public:
            EventQueue();
            ~EventQueue();
 
            EventQueue(const EventQueue&) = delete;
            EventQueue(EventQueue&&) = delete;
 
            EventQueue& operator=(const EventQueue&) = delete;
            EventQueue& operator=(EventQueue&&) = delete;
 
            void insert(Event* event);
            void remove(Event* event);
            void execute(const utils::Timeval& currentTime);
            bool empty() const;
            void clear();
 
        private:
            std::list<Event*>* executeQueue;
            std::list<Event*>* publishQueue;
        };
 
    public:
#define DISP_COUNT 3
 
        enum DISP_TYPE { RD = 0, WR = 1, EX = 2 };
 
        DescriptorEventPublisher& getDescriptorEventPublisher(DISP_TYPE dispType);
        TimerEventPublisher& getTimerEventPublisher();
 
        void span(core::Event* event);
        void relax(core::Event* event);
 
        void signal(int sigNum);
        void terminate();
        void clearEventQueue();
 
        TickStatus tick(const utils::Timeval& tickTimeOut, const sigset_t& sigMask);
 
    private:
        TickStatus waitForEvents(const utils::Timeval& tickTimeOut,
                                 const utils::Timeval& currentTime,
                                 const sigset_t& sigMask,
                                 int& activeDescriptorCount);
 
        void spanActiveEvents(const utils::Timeval& currentTime, int activeDescriptorCount);
        void executeEventQueue(const utils::Timeval& currentTime);
        void checkTimedOutEvents(const utils::Timeval& currentTime);
        void releaseExpiredResources(const utils::Timeval& currentTime);
 
        utils::Timeval getNextTimeout(const utils::Timeval& currentTime);
 
        virtual void spanActiveEvents(int activeDescriptorCount) = 0;
 
        virtual int monitorDescriptors(utils::Timeval& tickTimeOut, const sigset_t& sigMask) = 0;
 
    protected:
        int maxFd();
 
        std::array<DescriptorEventPublisher*, DISP_COUNT> descriptorEventPublishers;
 
    private:
        int observedEventReceiverCount();
 
        core::TimerEventPublisher* const timerEventPublisher;
 
        EventQueue eventQueue;
    };
 
} // namespace core
 
core::EventMultiplexer& EventMultiplexer();
 
#endif // CORE_EVENTMULTIPLEXER_H