linux下 c++实现 线程池——同步异步

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前言

我的技术栈都是在windows积累，然而c++后端开发主要是在Linux平台，这是对我的技术栈的一个迁移。

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一、线程池的结构

1. 一条线程安全的任务队列，负责为线程分配任务。
2. 一个线程管理类 handler，负责连接线程池与任务队列，以及线程之间的同步；
3. job struct
4. job_list记录
5. 线程池中线程分为两类同步或者异步,可以主线程发起一个异步线程，异步线程发去同步任务，增加逻辑处理效率。
本质上通过一条任务队列的入队出队，为线程池中的空闲线程分配任务。

二、代码示例

1.前置数据结构

#ifndef _THREADJOB_H_
#define _THREADJOB_H_

#include
#include

using namespace std;

typedef void* (*JobFunc)(void*);
typedef enum  _jobStatus {INIT=0,RUNNING,FREE,DIE} JobStatus;
typedef enum _jobType {THREAD_JOB=0,ASYIO_JOB} JobType;
struct Parems{
	void *args;
	JobFunc work_func;
};

struct Job{
	JobStatus job_status;
	Parems	parame;
	sem_t	*consume_sem;
	string	consumer_name;
	JobType	type;	  
};
#endif

2.线程池

1.类声明

#ifndef _THREADPOOL_H_
#define _THREADPOOL_H_

#include
#include
#include "Job.h"
#include "ThreadJobQueue.h"
using namespace std;

class threadPool{
private:
	int thread_num;
	string thread_pool_name;
    JobQueue<Job *> job_queue;
	list<pthread_t *>thread_list;
	bool stopFlag;
public:
	threadPool(int thread_num,string thread_pool_name);
	~threadPool();
	
	bool pushJob(Job *);
	Job *popJob();
	void setStopFlag(bool flag);
	bool getStopFlag();

	void init();
	void stop();

};

void InitPoolPtr(int thread_count);
threadPool *getThreadPoolPtr();
#endif

2.类定义

#include
#include 
#include "threadPool.h"
#include 
#include "ThreadJobQueue.h"
using namespace std;
static threadPool * thread_pool_ptr;

static string THREAD_POOL_LHL = "lhl_test";

threadPool::threadPool(int thread_num, string thread_pool_name) : thread_num(thread_num), thread_pool_name(thread_pool_name){
	stopFlag = true;
}

threadPool::~threadPool(){}

void threadPool::setStopFlag(bool flag){
	stopFlag = flag;
}

bool threadPool::getStopFlag(){
	return stopFlag;
}

void * work(void *arg){
	pthread_t tid = pthread_self();
	pthread_detach(tid);
	threadPool *lhl = (threadPool*)arg;
	while(lhl->getStopFlag()){
		Job *job = lhl->popJob();		
		if(job == NULL)
			continue;
		switch(job->type){
			case THREAD_JOB:	
				job->job_status = RUNNING;
				job->parame.work_func(job->parame.args);
				sem_post(job->consume_sem); 	
				break;
			case ASYIO_JOB:
				job->job_status = RUNNING;
                                job->parame.work_func(job->parame.args);
				delete job;
				break;				
		}
	}		
}

Job* threadPool::popJob(){
	Job *ret = NULL;
	job_queue.wait_and_pop(ret);
	return ret;
}

bool threadPool::pushJob(Job *job){
	if(job == NULL)
		return false;
	this->job_queue.push(job);
	return true;	
}

void threadPool::init(){
	for(int i = 0; i < thread_num; i++){
		pthread_t *thread = new pthread_t;
		int err = pthread_create(thread,NULL,work,(void*)this);
		if(err != 0){
			continue;
		}
		thread_list.push_back(thread);
	}
} 

void threadPool::stop(){
	this->setStopFlag(false);
	list<pthread_t  *>::iterator iter = this->thread_list.begin();
	for(;iter != this->thread_list.end(); iter++){
		delete *iter;	
	}
}

threadPool *getThreadPoolPtr(){
	return thread_pool_ptr;
}

void InitPoolPtr(int thread_count){
	thread_pool_ptr = new threadPool(thread_count,THREAD_POOL_LHL);
	thread_pool_ptr->init();
}

3.线程安全的队列

#ifndef _THREADJOBQUEUE_H_
#define  _THREADJOBQUEUE_H_

#include
#include
#include

using namespace std;

template<class Date>
class JobQueue{
private:
	std::queue<Date> job_queue;
	pthread_mutex_t mutex;
	pthread_cond_t condition;
public:
	JobQueue(){
		this->mutex = PTHREAD_MUTEX_INITIALIZER;
        this->condition = PTHREAD_COND_INITIALIZER;
}
	int queue_size(){
		pthread_mutex_lock(&this->mutex);
        int size = this->job_queue.size();
       	pthread_mutex_unlock(&this->mutex);
        return size;

}
	~JobQueue(){}
	void push(Date &date){
		pthread_mutex_lock(&mutex);
		job_queue.push(date);
 		pthread_mutex_unlock(&mutex);
	    pthread_cond_signal(&condition);
	}
	void wait_and_pop(Date &date){
		pthread_mutex_lock(&mutex);
        while(job_queue.empty()){
        	pthread_cond_wait(&condition,&mutex);
		}
        date = job_queue.front();
       	job_queue.pop();
        pthread_mutex_unlock(&mutex);
	}
};
#endif

4.threadHandler

#ifndef _THREADHANDLER_H_
#define _THREADHANDLER_H_

#include 
#include "Job.h"
#include "threadPool.h"

using namespace std; 

class Handler{
public:
	Handler(threadPool *thread_pool_ptr);
	~Handler();
	bool push(Job *job);
	void wait();
	int JobSize();
	Job *emptyJob();

private:
	void deleteJob();
	threadPool *thread_pool_ptr;
	sem_t *handler_sem;
	list<Job *> job_list;	

};
#endif

懒得贴代码，诸位自己想想吧。

5.测试用例

#include "threadHandler.h"
#include 
#include "threadPool.h"
#include 
void *test(void *test){
	std::cout<<*(string *)test<<std::endl;
}
void *testAsyio(void *ll){
	string str = "this is test";
	threadPool *ptr = getThreadPoolPtr();
	Handler handler(ptr);
	Job * job = handler.emptyJob();
	job->type = THREAD_JOB;
	job->parame.args = (void *) &str;
	job->parame.work_func = test;
	handler.push(job);
	handler.wait();
}

int main(){
	pthread_mutex_t mutex_test;
	mutex_test = PTHREAD_MUTEX_INITIALIZER;
	InitPoolPtr(5);
       
	threadPool *ptr = getThreadPoolPtr();
    Handler handler(ptr);
    Job * job = handler.emptyJob();
    job->type = ASYIO_JOB;
    job->parame.args = NULL;
    job->parame.work_func = testAsyio;
    handler.push(job);

	pthread_mutex_lock(&mutex_test);
	sleep(10);
	pthread_mutex_unlock(&mutex_test);
}

总结

出于熟悉Linux下的线程同步问题，我写了这线程池。