polling.h

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// Copyright 2021-2025 The Aerospace Corporation.
// This file is a part of SatCat5, licensed under CERN-OHL-W v2 or later.
 
 
#pragma once
 
#include <satcat5/timeref.h>
#include <satcat5/types.h>
 
namespace satcat5 {
    namespace poll {
        // Prototype for internal helper objects.
        class OnDemandHelper;
 
        void service();
 
        void service_all(unsigned limit = 100);
 
        bool pre_test_reset();
 
        class Always {
        public:
            virtual void poll_always() = 0;
 
            static unsigned count_always();
 
        protected:
            explicit Always(bool auto_register=true);
            ~Always() SATCAT5_OPTIONAL_DTOR;
 
            void poll_register();
 
            void poll_unregister();
 
        private:
            friend satcat5::poll::OnDemandHelper;
            friend satcat5::util::ListCore;
            friend void satcat5::poll::service();
            satcat5::poll::Always* m_next;  // Linked list to next object
        };
 
        class OnDemand {
        public:
            void request_poll();
 
            void request_cancel();
 
            static unsigned count_ondemand();
 
        protected:
            virtual void poll_demand() = 0;
 
            constexpr OnDemand() : m_next(0), m_idle(1) {}
            ~OnDemand() SATCAT5_OPTIONAL_DTOR;
 
        private:
            friend satcat5::util::ListCore;
            friend satcat5::poll::OnDemandHelper;
            friend satcat5::ptp::Interface;
            satcat5::poll::OnDemand* m_next;    // Linked list to next object
            bool m_idle;                        // Item currently idle?
        };
 
        class Timekeeper : public satcat5::poll::OnDemand {
        public:
            Timekeeper();
 
            satcat5::util::TimeRef* get_clock() const;
 
            bool clock_ready() const;
 
            void set_clock(satcat5::util::TimeRef* timer);
 
            void suggest_clock(satcat5::util::TimeRef* timer);
 
            bool pre_test_reset();
 
        protected:
            void poll_demand() override;
            satcat5::util::TimeVal m_tref;
        };
 
        extern Timekeeper timekeeper;
 
        class Timer {
        public:
            static unsigned count_timer();
 
            void timer_once(unsigned msec);
            void timer_every(unsigned msec);
            void timer_stop();
 
            inline unsigned timer_interval() const {return m_tnext;}
 
            inline unsigned timer_remaining() const {return m_trem;}
 
        protected:
            Timer();
            ~Timer() SATCAT5_OPTIONAL_DTOR;
 
            virtual void timer_event() = 0;
 
        private:
            // Event handler called by Timekeeper class.
            void query(unsigned elapsed_msec);
 
            friend satcat5::util::ListCore;
            friend satcat5::poll::Timekeeper;
            satcat5::poll::Timer* m_next;       // Linked list to next object
            unsigned m_trem;                    // Milliseconds to next event
            unsigned m_tnext;                   // Recurring timer interval
        };
 
        class TimerAdapter : public satcat5::poll::Timer {
        public:
            explicit TimerAdapter(satcat5::poll::OnDemand* target);
        protected:
            void timer_event() override;
            satcat5::poll::OnDemand* const m_target;
        };
    }
 
    namespace irq {
        class VirtualTimer : protected satcat5::poll::Always {
        public:
            VirtualTimer(
                satcat5::poll::OnDemand* obj, unsigned usec = 1000);
 
        protected:
            void poll_always() override;
 
            satcat5::poll::OnDemand* const m_target;
            unsigned const m_interval;
            satcat5::util::TimeVal m_tref;
        };
    }
}