#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include "threadpool.h"
#define DEFAULT_TIME 10 /*10s检测一次*/
#define MIN_WAIT_TASK_NUM 10 /*如果queue_size > MIN_WAIT_TASK_NUM 添加新的线程到线程池*/
#define DEFAULT_THREAD_VARY 10 /*每次创建和销毁线程的个数*/
#define true 1
#define false 0
typedef struct {
void *(*function)(void *); /* 函数指针，回调函数 */
void *arg; /* 上面函数的参数 */
} threadpool_task_t; /* 各子线程任务结构体 */
/* 描述线程池相关信息 */
struct threadpool_t {
pthread_mutex_t lock; /* 用于锁住本结构体 */
pthread_mutex_t thread_counter; /* 记录忙状态线程个数de琐 -- busy_thr_num */
pthread_cond_t queue_not_full; /* 当任务队列满时，添加任务的线程阻塞，等待此条件变量 */
pthread_cond_t queue_not_empty; /* 任务队列里不为空时，通知等待任务的线程 */
pthread_t *threads; /* 存放线程池中每个线程的tid。数组 */
pthread_t adjust_tid; /* 存管理线程tid */
threadpool_task_t *task_queue; /* 任务队列 */
int min_thr_num; /* 线程池最小线程数 */
int max_thr_num; /* 线程池最大线程数 */
int live_thr_num; /* 当前存活线程个数 */
int busy_thr_num; /* 忙状态线程个数 */
int wait_exit_thr_num; /* 要销毁的线程个数 */
int queue_front; /* task_queue队头下标 */
int queue_rear; /* task_queue队尾下标 */
int queue_size; /* task_queue队中实际任务数 */
int queue_max_size; /* task_queue队列可容纳任务数上限 */
int shutdown; /* 标志位，线程池使用状态，true或false */
};
/**
* @function void *threadpool_thread(void *threadpool)
* @desc the worker thread
* @param threadpool the pool which own the thread
*/
void *threadpool_thread(void *threadpool);
/**
* @function void *adjust_thread(void *threadpool);
* @desc manager thread
* @param threadpool the threadpool
*/
void *adjust_thread(void *threadpool);
/**
* check a thread is alive
*/
int is_thread_alive(pthread_t tid);
int threadpool_free(threadpool_t *pool);
threadpool_t *threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size)
{
int i;
threadpool_t *pool = NULL;
do {
if((pool = (threadpool_t *)malloc(sizeof(threadpool_t))) == NULL) {
printf("malloc threadpool fail");
break;/*跳出do while*/
}
pool->min_thr_num = min_thr_num;
pool->max_thr_num = max_thr_num;
pool->busy_thr_num = 0;
pool->live_thr_num = min_thr_num; /* 活着的线程数 初值=最小线程数 */
pool->queue_size = 0; /* 有0个产品 */
pool->queue_max_size = queue_max_size;
pool->queue_front = 0;
pool->queue_rear = 0;
pool->shutdown = false; /* 不关闭线程池 */
/* 根据最大线程上限数， 给工作线程数组开辟空间, 并清零 */
pool->threads = (pthread_t *)malloc(sizeof(pthread_t)*max_thr_num);
if (pool->threads == NULL) {
printf("malloc threads fail");
break;
}
memset(pool->threads, 0, sizeof(pthread_t)*max_thr_num);
/* 队列开辟空间 */
pool->task_queue = (threadpool_task_t *)malloc(sizeof(threadpool_task_t)*queue_max_size);
if (pool->task_queue == NULL) {
printf("malloc task_queue fail");
break;
}
/* 初始化互斥琐、条件变量 */
if (pthread_mutex_init(&(pool->lock), NULL) != 0
|| pthread_mutex_init(&(pool->thread_counter), NULL) != 0
|| pthread_cond_init(&(pool->queue_not_empty), NULL) != 0
|| pthread_cond_init(&(pool->queue_not_full), NULL) != 0)
{
printf("init the lock or cond fail");
break;
}
/* 启动 min_thr_num 个 work thread */
for (i = 0; i < min_thr_num; i++) {
pthread_create(&(pool->threads[i]), NULL, threadpool_thread, (void *)pool);/*pool指向当前线程池*/
printf("start thread 0x%x...\n", (unsigned int)pool->threads[i]);
}
pthread_create(&(pool->adjust_tid), NULL, adjust_thread, (void *)pool);/* 启动管理者线程 */
return pool;
} while (0);
threadpool_free(pool); /* 前面代码调用失败时，释放poll存储空间 */
return NULL;
}
/* 向线程池中 添加一个任务 */
int threadpool_add(threadpool_t *pool, void*(*function)(void *arg), void *arg)
{
pthread_mutex_lock(&(pool->lock));
/* ==为真，队列已经满， 调wait阻塞 */
while ((pool->queue_size == pool->queue_max_size) && (!pool->shutdown)) {
pthread_cond_wait(&(pool->queue_not_full), &(pool->lock));
}
if (pool->shutdown) {
pthread_mutex_unlock(&(pool->lock));
}
/* 清空 工作线程 调用的回调函数 的参数arg */
if (pool->task_queue[pool->queue_rear].arg != NULL) {
free(pool->task_queue[pool->queue_rear].arg);
pool->task_queue[pool->queue_rear].arg = NULL;
}
/*添加任务到任务队列里*/
pool->task_queue[pool->queue_rear].function = function;
pool->task_queue[pool->queue_rear].arg = arg;
pool->queue_rear = (pool->queue_rear + 1) % pool->queue_max_size; /* 队尾指针移动, 模拟环形 */
pool->queue_size++;
/*添加完任务后，队列不为空，唤醒线程池中 等待处理任务的线程*/
pthread_cond_signal(&(pool->queue_not_empty));
pthread_mutex_unlock(&(pool->lock));
return 0;
}
/* 线程池中各个工作线程 */
void *threadpool_thread(void *threadpool)
{
threadpool_t *pool = (threadpool_t *)threadpool;
threadpool_task_t task;
while (true) {
/* Lock must be taken to wait on conditional variable */
/*刚创建出线程，等待任务队列里有任务，否则阻塞等待任务队列里有任务后再唤醒接收任务*/
pthread_mutex_lock(&(pool->lock));
/*queue_size == 0 说明没有任务，调 wait 阻塞在条件变量上, 若有任务，跳过该while*/
while ((pool->queue_size == 0) && (!pool->shutdown)) {
printf("thread 0x%x is waiting\n", (unsigned int)pthread_self());
pthread_cond_wait(&(pool->queue_not_empty), &(pool->lock));
/*清除指定数目的空闲线程，如果要结束的线程个数大于0，结束线程*/
if (pool->wait_exit_thr_num > 0) {
pool->wait_exit_thr_num--;
/*如果线程池里线程个数大于最小值时可以结束当前线程*/
if (pool->live_thr_num > pool->min_thr_num) {
printf("thread 0x%x is exiting\n", (unsigned int)pthread_self());
pool->live_thr_num--;
pthread_mutex_unlock(&(pool->lock));
pthread_exit(NULL);
}
}
}
/*如果指定了true，要关闭线程池里的每个线程，自行退出处理*/
if (pool->shutdown) {
pthread_mutex_unlock(&(pool->lock));
printf("thread 0x%x is exiting\n", (unsigned int)pthread_self());
pthread_exit(NULL); /* 线程自行结束 */
}
/*从任务队列里获取任务, 是一个出队操作*/
task.function = pool->task_queue[pool->queue_front].function;
task.arg = pool->task_queue[pool->queue_
