利用libevent 和线程池实现高并发服务器的设计

主进程添加监听套接字的事件并进行事件循环，将连接描述符放入定义的数据结构中，并在主进程中进行写管道，触发子线程的读管道事件，然后从连接结构中获取连接描述符进行和客户端进行通信。其中主进程和子线程都有不同的基事件base.

#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <pthread.h>#include <sys/types.h>#include <sys/socket.h>#include <event.h>#include <queue>#include <iostream>#include <arpa/inet.h>#include <memory.h>const int thread_num = 10;#define BUF_SIZE 1024using namespace std;typedef struct {    pthread_t tid;    struct event_base *base;    struct event event;    int read_fd;    int write_fd;    //queue<int> q;    int f_connect;    char * buffer;}LIBEVENT_THREAD;                 //需要保存的信息结构，用于管道通信和基事件的管理typedef struct {    pthread_t tid;    struct event_base *base;}DISPATCHER_THREAD;LIBEVENT_THREAD *threads = (LIBEVENT_THREAD *) calloc(thread_num, sizeof(LIBEVENT_THREAD));void on_write(int sock, short event, void* arg);void on_read(int sock, short event, void* arg){    cout<<"on_read() called, sock="<<sock<<endl;    if(NULL == arg){        return;    }    LIBEVENT_THREAD* event_thread = (LIBEVENT_THREAD*) arg;//获取传进来的参数    char* buffer = new char[BUF_SIZE];    memset(buffer, 0, sizeof(char)*BUF_SIZE);    //--本来应该用while一直循环，但由于用了libevent，只在可以读的时候才触发on_read(),故不必用while了    int size = read(sock, buffer, BUF_SIZE);    if(0 == size){//说明socket关闭        cout<<"read size is 0 for socket:"<<sock<<endl;      //  destroy_sock_ev(event_struct);      //event_thread->q.pop();       close(sock);        return;    }    cout<<"i have receive: "<<buffer<<endl;    event_thread->buffer=buffer;    struct event* write_ev = (struct event*)malloc(sizeof(struct event));//发生写事件（也就是只要socket缓冲区可写）时，就将反馈数据通过socket写回客户端    event_set(write_ev, sock, EV_WRITE, on_write, event_thread);    event_base_set(event_thread->base, write_ev);    event_add(write_ev, NULL);    cout<<"on_read() finished, sock="<<sock<<endl;}void on_write(int sock, short event, void* arg){    if(NULL == arg){        return;    }    LIBEVENT_THREAD* event_write_thread = (LIBEVENT_THREAD*) arg;//获取传进来的参数    //char* buffer = new char[BUF_SIZE];    //memset(buffer, 0, sizeof(char)*BUF_SIZE);    //strcpy(buffer,event_write_thread->buffer,sizeof(event_write_thread->buffer));    //--本来应该用while一直循环，但由于用了libevent，只在可以读的时候才触发on_read(),故不必用while了    write(sock, event_write_thread->buffer, BUF_SIZE);    free(event_write_thread->buffer);    event_write_thread->buffer=NULL;}static void thread_libevent_process(int fd, short which, void *arg){    int ret;    char buf[128];    LIBEVENT_THREAD *me = (LIBEVENT_THREAD *) arg;    int fdconnect;    if (fd != me->read_fd) {        printf("thread_libevent_process error : fd != me->read_fd\n");        exit(1);    }            ret = read(fd, buf, 128);           if (ret > 0)             {              buf[ret] = '\0';              printf("thread %llu receive message : %s\n", (unsigned long long)me->tid, buf);            }           cout<<"thread_libevent_process\n"<<endl;    /*if(me->q.size()>0)        {            fdconnect=me->q.front();            me->q.pop();           ret = read(fd, buf, 128);           if (ret > 0)             {              buf[ret] = '\0';              printf("thread %llu receive message : %s\n", (unsigned long long)me->tid, buf);            }        }*/        /*if(me->q.size()>0)        {            fdconnect=me->q.front();            cout<<"thread_libevent_process succeed "<<endl;            //me->q.pop();        }        else            return ;*/        fdconnect=me->f_connect;        struct event* read_ev = (struct event*)malloc(sizeof(struct event));//发生读事件后，从socket中取出数据        event_set(read_ev, fdconnect, EV_READ|EV_PERSIST, on_read, me);        event_base_set(me->base, read_ev);        event_add(read_ev, NULL);    return;}void thread_init(){    int ret;    int fd[2];    for (int i = 0; i < thread_num; i++) {            ret = socketpair(AF_LOCAL, SOCK_STREAM, 0, fd);            if (ret == -1) {                perror("socketpair()");                return  ;            }            threads[i].read_fd = fd[0];            threads[i].write_fd = fd[1];            threads[i].base = event_init();            if (threads[i].base == NULL) {                perror("event_init()");                return ;            }            event_set(&threads[i].event,threads[i].read_fd, EV_READ | EV_PERSIST, thread_libevent_process, &threads[i]);            event_base_set(threads[i].base, &threads[i].event);            if (event_add(&threads[i].event, 0) == -1) {                perror("event_add()");                return ;            }            cout<<"thread_init succeed"<<endl;        }} void * worker_thread(void *arg){    LIBEVENT_THREAD *me = (LIBEVENT_THREAD *)arg;    me->tid = pthread_self();    //event_base_loop(me->base, 0);     event_base_dispatch(me->base);    return NULL;}void CreatPhreadPool(){    for (int i = 0; i < thread_num; i++) {        pthread_create(&threads[i].tid, NULL, worker_thread, &threads[i]);    }    cout<<"CreatPhreadPool"<<endl;}int getSocket(){    int fd =socket( AF_INET, SOCK_STREAM, 0 );    if(-1 == fd){        cout<<"Error, fd is -1"<<endl;    }    return fd;}int last_thread=0;void event_handler(int sock, short event, void* arg)  //添加其他信息{    struct sockaddr_in remote_addr;    int sin_size=sizeof(struct sockaddr_in);    int new_fd = accept(sock,  (struct sockaddr*) &remote_addr, (socklen_t*)&sin_size);    //如果线程池已用完，怎么办呢？    if(new_fd < 0){        cout<<"Accept error in on_accept()"<<endl;        return;    }    cout<<"new_fd accepted is "<<new_fd<<endl;    int tid = (last_thread + 1) % thread_num;        //memcached中线程负载均衡算法    LIBEVENT_THREAD *thread = threads + tid;    last_thread = tid;      thread->f_connect=new_fd;    write(thread->write_fd, " ", 1);    cout<<"on_accept() finished for fd="<<new_fd<<endl;}DISPATCHER_THREAD dispatcher_thread;        //用于设置主线程的结构变量int main(int argc, char** argv)  {     thread_init();     CreatPhreadPool();    int fd_listen = getSocket();     if(fd_listen <0){         cout<<"Error in main(), fd<0"<<endl;     }     //cout<<"main() fd="<<fd<<endl;     //----为服务器主线程绑定ip和port------------------------------     struct sockaddr_in local_addr; //服务器端网络地址结构体     memset(&local_addr,0,sizeof(local_addr)); //数据初始化--清零     local_addr.sin_family=AF_INET; //设置为IP通信     local_addr.sin_addr.s_addr=inet_addr(argv[1]);//服务器IP地址     local_addr.sin_port=htons(atoi(argv[2])); //服务器端口号     int bind_result = bind(fd_listen, (struct sockaddr*) &local_addr, sizeof(struct sockaddr));     if(bind_result < 0){         cout<<"Bind Error in main()"<<endl;         return -1;     }     cout<<"bind_result="<<bind_result<<endl;     listen(fd_listen, 10);      evutil_make_socket_nonblocking(fd);     //-----设置libevent事件，每当socket出现可读事件，就调用on_accept()------------     struct event_base* base = event_base_new();     dispatcher_thread.base=base;     dispatcher_thread.tid = pthread_self();     struct event listen_ev;     event_set(&listen_ev, fd_listen, EV_READ|EV_PERSIST, event_handler, NULL);     event_base_set(dispatcher_thread.base, &listen_ev);     event_add(&listen_ev, NULL);     event_base_dispatch(dispatcher_thread.base);     //------以下语句理论上是不会走到的---------------------------     cout<<"event_base_dispatch() in main() finished"<<endl;     //----销毁资源-------------     event_del(&listen_ev);     event_base_free(dispatcher_thread.base);     cout<<"main() finished"<<endl;}

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