HydraV3/HydraEngine/source/scheduler/HydraTaskScheduler.h

#ifndef HYDRATASKSCHEDULER
#define HYDRATASKSCHEDULER

#include "../engine/HydraObject.h"
#include "HydraTaskBarrier.h"
#include "../task/HydraTask.h"
#include <vector>
#include <deque>
#include <mutex>
#include <queue>
#include <thread>

class HydraThread;
class HydraWorkItem;
// class HydraTask;

class CLASS_DEFINE HydraTaskScheduler : public HydraObject
{
private:
    std::vector<HydraTaskBarrier *> m_barriers;
    std::queue<HydraID> m_available_barrier_ids;
    std::mutex m_mutex;

    bool m_waiting = false;
    bool m_running = true;
    HydraID m_waiting_id = INVALID_HYDRA_ID;
    std::vector<HydraThread *> m_general_thread;

    HydraThread *m_render_thread = nullptr;
    HydraThread *m_physics_thread = nullptr;

    std::vector<HydraTask *> m_tasks;
    std::vector<HydraID> m_task_ids_waiting_for_children;

    std::deque<HydraID> m_avaialble_task_ids;
    std::deque<HydraID> m_general_tasks_ready_to_run;
    std::deque<HydraID> m_render_tasks_ready_to_run;
    std::deque<HydraID> m_physics_tasks_ready_to_run;

    HydraID _SaveTask(HydraTask *taskItem);

    HydraID _GetRenderTaskReadyToRun();
    HydraID _GetPhysicsTaskReadyToRun();
    void _DecrementBarrier(HydraID taskID, HydraID barrierID);
    void _UpdateDependantTaskComplete(HydraID taskID);
    void _DeleteTask(HydraID taskID);
    void _AddTaskToBarrier(HydraID taskID, HydraID barrierID);
    void _StartTask(HydraID taskID, bool notifyThread = false);
    void _NotifyThread(std::thread::id thread_id);
    HydraID _CreateBarrier();
    HydraTask *const _GetTask(HydraID taskID);
    HydraID _GetTaskReadyToRun(HydraThreadAffinity thread_affinity);
    void _CompleteBarrier(uint32_t barrierID);
protected:
public:
    template <class T>
    HydraID CreateTask(HydraThreadAffinity ThreadAffinity, HydraID barrierID = INVALID_HYDRA_ID);
    template <class T>
    HydraID CreateAndStartTask(HydraThreadAffinity ThreadAffinity, HydraID barrierID = INVALID_HYDRA_ID);
    HydraTask *const GetTask(HydraID taskID);
    void StartTask(HydraID taskID);
    void WaitForTask(HydraID taskID);
    HydraID CreateBarrier();
    void AddTaskToBarrier(HydraID taskID, HydraID barrierID);
    void WaitForBarrier(HydraID barrierID);
    void DecrementBarrier(HydraID taskID, HydraID barrierID);

    void Initialise(int thread_count);
    void Shutdown();

    void NotifyStart(HydraID taskID);
    void NotifyComplete(HydraID taskID);
    void ProcessTask();

    void DeleteTask(HydraID taskID);
};

template <class T>
inline HydraID HydraTaskScheduler::CreateTask(HydraThreadAffinity ThreadAffinity, HydraID barrierID)
{
    std::lock_guard<std::mutex> lock(m_mutex);
    T *taskType = new T();
    HydraTask *task = dynamic_cast<HydraTask *>(taskType);
    if (task != nullptr)
    {
        task->m_barrierID = barrierID;
        task->ThreadAffinity = ThreadAffinity;
        HydraID id = _SaveTask(task);
        if (id != INVALID_HYDRA_ID)
        {
            _AddTaskToBarrier(id, barrierID);
        }
        else
        {
            delete taskType;
        }
        return id;
    }
    else
    {
        delete taskType;
        return INVALID_HYDRA_ID;
    }
};
template <class T>
inline HydraID HydraTaskScheduler::CreateAndStartTask(HydraThreadAffinity ThreadAffinity, HydraID barrierID)
{

    HydraID taskID = CreateTask<T>(ThreadAffinity, barrierID);
    if (taskID != INVALID_HYDRA_ID)
    {
        StartTask(taskID);
    }
    return taskID;
};

#endif /* HYDRATASKSCHEDULER */