threadpool.h

#ifndef THREADPOOL_H
#define THREADPOOL_H

#include <list>
#include <pthread.h>
#include <cstdio>
#include <exception>
#include "locker.h"

template<typename T>
class threadpool{
public:
    threadpool(int thread_number=8, int max_requests=10000);
    ~threadpool();
    bool append(T* request);
private:
    int thread_number; //number of threads
    pthread_t *m_threads; //an array of threads
    int max_requests; //the max number of requests
    std::list<T*> m_workqueue; //the working queue
    locker m_queuelocker;
    sem m_queuestat;
    bool m_stop; //whether to stop the threads  
    static void* worker(void* arg);
    void run();
};

template <typename T>
threadpool<T>::threadpool(int thread_number,int max_requests) :
    thread_number(thread_number),max_requests(max_requests),
    m_stop(false),m_threads(NULL){
    if(thread_number<=0 || max_requests<=0){
        throw std::exception();
    }
    m_threads = new pthread_t[thread_number];
    if(!m_threads){
        throw std::exception();
    }
    for(int i=0;i<thread_number;i++){
        printf("Create the %dth thread\n",i);
        if(pthread_create(m_threads+i, NULL, worker, this)!=0){
            delete [] m_threads;
            throw std::exception();
        }
        if(pthread_detach(m_threads[i])){
            delete [] m_threads;
            throw std::exception();
        }
    }

}
template<typename T>
threadpool<T>::~threadpool(){
    delete [] m_threads;
    m_stop = true;
}

template<typename T>
bool threadpool<T>::append(T* request){
    m_queuelocker.lock();
    if(m_workqueue.size()>max_requests){
        m_queuelocker.unlock();
        return false;
    }
    m_workqueue.push_back(request);
    m_queuelocker.unlock();
    m_queuestat.post();
    return true;
}

template<typename T>
void* threadpool<T>::worker(void * arg){
    threadpool* pool = (threadpool*)arg;
    pool->run();
    return pool;
}

template <typename T>
void threadpool<T>::run(){
    while(!m_stop){
        m_queuestat.wait();
        m_queuelocker.lock();
        if(m_workqueue.empty()){
            m_queuelocker.unlock();
            continue;
        }
        T* request = m_workqueue.front();
        m_workqueue.pop_front();
        m_queuelocker.unlock();
        if(!request){
            continue;
        }
        request->process();
    }
}

#endif