threadpool.h

//
// Created by Jason.Z on 2020/6/23.
//

#ifndef SOCKETSERVERCPLUS_THREADPOOL_H
#define SOCKETSERVERCPLUS_THREADPOOL_H
#include <pthread.h>
#include <functional>
#include <memory>
#include <vector>


const int THREADPOOL_INVALID = -1;
const int THREADPOOL_LOCK_FAILURE = -2;
const int THREADPOOL_QUEUE_FULL = -3;
const int THREADPOOL_SHUTDOWN = -4;
const int THREADPOOL_THREAD_FAILURE = -5;
const int THREADPOOL_GRACEFUL = 1;

const int MAX_THREADS = 1024;
const int MAX_QUEUE = 65535;

typedef enum
{
    immediate_shutdown = 1,
    graceful_shutdown  = 2
} ShutDownOption;

struct ThreadPoolTask
{
    std::function<void(std::shared_ptr<void>)> fun;
    std::shared_ptr<void> args;
};

/**
 *  @struct threadpool
 *  @brief The threadpool struct
 *
 *  @var notify       Condition variable to notify worker threads.
 *  @var threads      Array containing worker threads ID.
 *  @var thread_count Number of threads
 *  @var queue        Array containing the task queue.
 *  @var queue_size   Size of the task queue.
 *  @var head         Index of the first element.
 *  @var tail         Index of the next element.
 *  @var count        Number of pending tasks
 *  @var shutdown     Flag indicating if the pool is shutting down
 *  @var started      Number of started threads
 */
void myHandler(std::shared_ptr<void> req);

class ThreadPool
{
public:
    static pthread_mutex_t lock;
    static pthread_cond_t notify;
    static std::vector<pthread_t> threads;
    static std::vector<ThreadPoolTask> queue;
    static int thread_count;
    static int queue_size;
    static int head;
    // tail 指向尾节点的下一节点
    static int tail;
    static int count;
    static int shutdown;
    static int started;
    static int running_threads;
    static int waiting_threads;

public:
    static int threadpool_create(int _thread_count, int _queue_size);
    static int threadpool_add(const std::shared_ptr<void>& args, const std::function<void(std::shared_ptr<void>)>& fun = myHandler);
    static int threadpool_destroy(ShutDownOption shutdown_option = graceful_shutdown);
    static int threadpool_free();
    static void *threadpool_thread(void *args);
};

#endif //SOCKETSERVERCPLUS_THREADPOOL_H