threadpool.h

#ifndef THREADPOOL_H
#define THREADPOOL_H

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <assert.h>
#include "FSManalyzer.h"

//#define THREAD_NUM 4

typedef struct worker{
	//callback function
	void *(*process)(void *arg);
	//the arg
	void *arg;
	struct worker *next;
}THREAD_WORKER;

typedef struct{
	/* data */
	pthread_mutex_t queue_lock;
	pthread_cond_t queue_ready;
	pthread_t *thread_id;

	/*链表结构，线程池中所有等待任务*/ 
	THREAD_WORKER *queue_head;

	/*是否销毁线程池*/  
    int shutdown;  
     
    /*线程池中允许的活动线程数目*/  
    int max_thread_num;  
    /*当前等待队列的任务数目*/  
    int cur_queue_size; 
}THREAD_POOL;

int pool_add_worker (void *(*process) (void *arg), void *arg);  
void *thread_routine (void *arg); 

//share resource  
static THREAD_POOL *pool = NULL;  

void pool_init (int max_thread_num)  
{  
    pool = (THREAD_POOL *) malloc (sizeof (THREAD_POOL));  
  	//初始化互斥锁
    pthread_mutex_init (&(pool->queue_lock), NULL);
    //初始化一个条件变量
    pthread_cond_init (&(pool->queue_ready), NULL);  
  
    pool->queue_head = NULL;  
  
    pool->max_thread_num = max_thread_num;  
    pool->cur_queue_size = 0;  
  
    pool->shutdown = 0;  
  	//创建所有线程的ID
    pool->thread_id = (pthread_t *) malloc (max_thread_num * sizeof (pthread_t));
    //创建所有线程
    int i = 0;  
    for (i = 0; i < max_thread_num; i++)  
    {   
        pthread_create (&(pool->thread_id[i]), NULL, thread_routine,NULL);  
    }  
}

/*向线程池中加入任务*/  
int pool_add_worker (void *(*process) (void *arg), void *arg)  
{  
    /*构造一个新任务*/  
    THREAD_WORKER *newworker = (THREAD_WORKER *) malloc (sizeof (THREAD_WORKER));  
    newworker->process = process;  
    newworker->arg = arg;  
    newworker->next = NULL;/*别忘置空*/  
  	
    pthread_mutex_lock (&(pool->queue_lock));  
    /*将任务加入到等待队列中的队尾*/  
    THREAD_WORKER *member = pool->queue_head;  
    if (member != NULL)  
    {  
        while (member->next != NULL)  
            member = member->next;  
        member->next = newworker;  
    }  
    else  
    {  
        pool->queue_head = newworker;  
    }  
  
    assert (pool->queue_head != NULL);  
  
    pool->cur_queue_size++;  
    pthread_mutex_unlock (&(pool->queue_lock));  
    /*好了，等待队列中有任务了，唤醒一个等待线程； 
    注意如果所有线程都在忙碌，这句没有任何作用*/  
    pthread_cond_signal (&(pool->queue_ready));
    printf("signal a pthread!\n");
    return 0;  
}
  
/*销毁线程池，等待队列中的任务不会再被执行，但是正在运行的线程会一直 
把任务运行完后再退出*/  
int pool_destroy ()  
{  
    if (pool->shutdown)  
        return -1;/*防止两次调用*/  
    pool->shutdown = 1;  
  
    /*唤醒所有等待线程，线程池要销毁了*/  
    pthread_cond_broadcast (&(pool->queue_ready));  
  
    /*阻塞等待线程退出，否则就成僵尸了*/  
    int i;  
    for (i = 0; i < pool->max_thread_num; i++)  
        pthread_join (pool->thread_id[i], NULL);  
    free (pool->thread_id);  
  
    /*销毁等待队列*/  
    THREAD_WORKER *head = NULL;  
    while (pool->queue_head != NULL)  
    {  
        head = pool->queue_head;  
        pool->queue_head = pool->queue_head->next;  
        free (head);  
    }  
    /*条件变量和互斥量也别忘了销毁*/  
    pthread_mutex_destroy(&(pool->queue_lock));  
    pthread_cond_destroy(&(pool->queue_ready));  
      
    free (pool);  
    /*销毁后指针置空是个好习惯*/  
    pool=NULL;
    return 0;  
}  
  
void *thread_routine (void *arg)  
{  
    printf ("starting thread 0x%lx\n", pthread_self());  
    while (1)  
    {  
        pthread_mutex_lock (&(pool->queue_lock));  
        /*如果等待队列为0并且不销毁线程池，则处于阻塞状态; 注意 
        pthread_cond_wait是一个原子操作，等待前会解锁，唤醒后会加锁*/  
        while (pool->cur_queue_size == 0 && !pool->shutdown)  
        {  
            printf ("thread 0x%lx is waiting\n", pthread_self());  
            pthread_cond_wait (&(pool->queue_ready), &(pool->queue_lock));  
        }  
  
        /*线程池要销毁了*/  
        if (pool->shutdown)  
        {  
            /*遇到break,continue,return等跳转语句，千万不要忘记先解锁*/  
            pthread_mutex_unlock (&(pool->queue_lock));  
            printf ("thread 0x%lx will exit\n", pthread_self());  
            pthread_exit (NULL);  
        }  
  
        printf ("thread 0x%lx is starting to work\n", pthread_self());  
  
        /*assert是调试的好帮手*/  
        assert (pool->cur_queue_size != 0);  
        assert (pool->queue_head != NULL);  
          
        /*等待队列长度减去1，并取出链表中的头元素*/  
        pool->cur_queue_size--;  
        THREAD_WORKER *worker = pool->queue_head;  
        pool->queue_head = worker->next;  
        pthread_mutex_unlock (&(pool->queue_lock));  
  
        /*调用回调函数，执行任务*/  
        (*(worker->process)) (worker->arg);
        
        free (worker);  
        worker = NULL;  
    }  
    /*这一句应该是不可达的*/  
    pthread_exit (NULL);  
}  
  
//    下面是测试代码  
  
void *myprocess (void *arg)  
{
    printf ("threadid is 0x%lx, working on task %d\n", pthread_self(),*(int *) arg);  
    sleep (1);/*休息一秒，延长任务的执行时间*/  
    return NULL;  
}

void *analysis_thread_dispatch(void *arg){

    pool_init(0);
    printf("begin the analysis_thread_dispatch\n");
    while(1){
        pool_add_worker(Analysis,NULL);
    }

    pool_destroy();

}
/*
int main(int argc, char const *argv[])
{
	
    pool_init(4);

    int* worknum=(int*)malloc(sizeof(int)*10);
    int i;
    for (i = 0; i < 10; i++){

        worknum[i]=i;
        pool_add_worker(myprocess,&worknum[i]);

    }

    sleep(5);

    pool_destroy();

    free(worknum);
	return 0;
}*/

#endif