ant-http/libs/scheduler.h

#ifndef ANT_SCHEDULER
#define ANT_SCHEDULER

#include "utils.h"
#include <pthread.h>

#define N_PRIORITY 10
#define NORMAL_PRIORITY ((int)((N_PRIORITY - 1) / 2))
#define LOW_PRIORITY (N_PRIORITY - 1)
#define HIGH_PRIORITY 0

typedef enum { LIGHT, HEAVY } antd_task_type_t;
// callback definition
typedef struct __callback_t{
    void* (*handle)(void*);
    struct __callback_t * next;
} antd_callback_t;
// task definition
typedef struct {
    /*
        creation time of a task
    */
    unsigned long stamp;
    /*
        priority from 0 to N_PRIORITY - 1
        higher value is lower priority
    */
    uint8_t priority;
    /*
        the callback
    */
   void* (*handle)(void*);
   antd_callback_t* callback;
   /*
        user data if any
   */
    void * data;
    /*
    type of a task
    light tasks are executed directly
    heavy tasks are delegated to workers
    */
   antd_task_type_t type;
} antd_task_t;


typedef struct __task_item_t{
    antd_task_t* task;
    struct __task_item_t* next;
}* antd_task_item_t;

typedef antd_task_item_t antd_task_queue_t;

typedef struct {
    pthread_mutex_t scheduler_lock;
    pthread_mutex_t worker_lock;
    pthread_mutex_t pending_lock;
    antd_task_queue_t task_queue[N_PRIORITY];
    antd_task_queue_t workers_queue;
    uint8_t status; // 0 stop, 1 working
    pthread_t* workers;
    int n_workers;
    int pending_task;
} antd_scheduler_t;

/*
    init the main scheduler
*/
void antd_scheduler_init(antd_scheduler_t*, int);
/*
    destroy all pending task
*/
void antd_scheduler_destroy(antd_scheduler_t*);

/*
    create a task
*/
antd_task_t* antd_create_task(void* (*handle)(void*), void *data, void* (*callback)(void*));

/*
    add a task
*/
void antd_add_task(antd_scheduler_t*, antd_task_t*);
/*
    execute and free a task a task
*/
void antd_execute_task(antd_scheduler_t*, antd_task_item_t);
/*
    scheduler status
*/
int antd_scheduler_busy(antd_scheduler_t*);
/*
    schedule a task
*/
void antd_task_schedule(antd_scheduler_t*);
#endif