scheduler.hpp

/*
 * Copyright 2021 Marcus Behel
 *
 * This file is part of ArPiRobot-CoreLib.
 * 
 * ArPiRobot-CoreLib 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.
 * 
 * ArPiRobot-CoreLib 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 ArPiRobot-CoreLib.  If not, see <https://www.gnu.org/licenses/>. 
 */
 
#pragma once
 
#include <functional>
#include <chrono>
#include <memory>
#include <atomic>
#include <mutex>
#include <future>
#include <map>
#include <ctpl_stl.h>
 
namespace arpirobot{
 
    using sched_clk = std::chrono::system_clock;
 
    class Task{
    public:
        Task(const std::function<void()> &&f);
 
        virtual sched_clk::time_point nextRunTime();
    
        virtual bool doesRepeat();
 
        std::function<void()> targetFunction;
    };
 
    class RepeatedTask : public Task{
    public:
        RepeatedTask(const std::function<void()> &&f, sched_clk::duration rate);
 
        sched_clk::time_point nextRunTime();
 
        bool doesRepeat();
    
        sched_clk::duration rate;
    };
 
    class SchedSleeper{
    public:
        SchedSleeper();
        
        void sleep_for(sched_clk::duration duration);
 
        void sleep_until(sched_clk::time_point time);
 
        void sleep();
 
        void interrupt();
    
    private:
        bool interrupted;
        std::mutex m;
        std::condition_variable cv;
    };
 
    class Scheduler{
    public:
        Scheduler(unsigned int maxThreads = 4);
        ~Scheduler();
 
        // Add a task to be run once
        std::shared_ptr<Task> addTask(const std::function<void()> &&targetFunc, sched_clk::time_point::duration delay);
 
        // Add a task to be run periodically (at given rate)
        std::shared_ptr<Task> addRepeatedTask(const std::function<void()> &&targetFunc, sched_clk::time_point::duration delay, 
            sched_clk::time_point::duration rate);
        
        // Remove a task (only really useful for repeated tasks)
        void removeTask(std::shared_ptr<Task> task);
    
    private:
        void serviceTasks();
 
        std::atomic<bool> done;
        SchedSleeper sleeper;
        std::multimap<sched_clk::time_point, std::shared_ptr<Task>> tasks;
        std::mutex lock;
        ctpl::thread_pool threads;
    };
 
}