DescriptorEventReceiver.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_DESCRIPTOREVENTRECEIVER_H
#define CORE_DESCRIPTOREVENTRECEIVER_H
 
#include "core/EventReceiver.h" // IWYU pragma: export
 
namespace core {
    class DescriptorEventPublisher;
} // namespace core
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#include "utils/Timeval.h"
 
#include <string>
 
#endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
namespace core {
 
    class Observer {
    public:
        Observer() = default;
        Observer(Observer&) = delete;
        Observer(Observer&&) = delete;
 
        virtual ~Observer();
 
    protected:
        void observed();
        void unObserved();
 
        virtual void unobservedEvent() = 0;
 
    private:
        int observationCounter = 0;
    };
 
    class DescriptorEventReceiver
        : virtual protected Observer
        , public EventReceiver {
    public:
        struct TIMEOUT {
            static const utils::Timeval DEFAULT;
            static const utils::Timeval DISABLE;
            static const utils::Timeval MAX;
        };
 
        DescriptorEventReceiver(const std::string& name,
                                DescriptorEventPublisher& descriptorEventPublisher,
                                const utils::Timeval& timeout = TIMEOUT::DISABLE);
 
        int getRegisteredFd() const;
 
    protected:
        bool enable(int fd);
        void disable();
 
        void suspend();
        void resume();
 
    public:
        bool isEnabled() const;
        bool isSuspended() const;
 
        void setTimeout(const utils::Timeval& timeout);
        utils::Timeval getTimeout(const utils::Timeval& currentTime) const;
 
        void checkTimeout(const utils::Timeval& currentTime);
 
    private:
        void onEvent(const utils::Timeval& currentTime) final;
        void onSignal(int signum);
 
        void triggered(const utils::Timeval& currentTime);
        void setEnabled(const utils::Timeval& currentTime);
        void setDisabled();
 
        virtual void dispatchEvent() = 0;
        virtual void timeoutEvent() = 0;
        virtual void signalEvent(int signum) = 0;
 
        DescriptorEventPublisher& descriptorEventPublisher;
 
        int observedFd = -1;
 
        bool enabled = false;
        bool suspended = false;
 
        utils::Timeval lastTriggered;
        utils::Timeval maxInactivity;
        const utils::Timeval initialTimeout;
 
        int eventCounter = 0;
 
        friend class DescriptorEventPublisher;
    };
 
} // namespace core
 
#endif // CORE_DESCRIPTOREVENTRECEIVER_H