epoll的et和lt模式(5)

//现在用linux做服务器，高并发的epoll占了很重要部分吧。
//设计模式+epoll+fcntl全都可以开发了,这些如果没在项目中实践，要理解也是挺难的。

 1 //《linux高性能服务器编程》9.3章
//略微改了些代码

#include <iostream>
using namespace std;

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/epoll.h>
#include <fcntl.h>

#define MAX_EVENTS 1024
#define BUFFER_SIZE 10

//设置非阻塞
void setnonblocking(int fd)
{
    int oldfd = fcntl(fd, F_GETFL);
    int newfd = oldfd | O_NONBLOCK;
    fcntl(fd, F_SETFL, newfd);
}

//epoll注册
void addfd(int epollfd, int fd, bool bET)
{
    epoll_event event;
    event.data.fd = fd;
    event.events = EPOLLIN;

    //设置ET模式
    if(bET)
    {
        event.events |= EPOLLET;    
    }
    epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &event);
    setnonblocking(fd);
}

void epollwork(epoll_event* events, int number, int epollfd, int listenfd, bool bET)
{
    char buf[BUFFER_SIZE];
    for(int i=0; i<number; i++)
    {
        int sockfd = events[i].data.fd;
        //conn
        if(sockfd == listenfd)
        {
            sockaddr_in cliAddr;
            socklen_t cliLen = sizeof(cliAddr);
            int connfd = accept(listenfd, (sockaddr*)&cliAddr, &cliLen);    
            if(connfd < 0 )
            {cout<<"accept error"<<endl;continue;}

            addfd(epollfd, connfd, true);

            cout<<"conn:"<<connfd<<","<<endl;
        }
        //recv
        else if(events[i].events & EPOLLIN)
        {
            //et
            if(bET)
            {
            //ET循环处理内核缓存数据,
            while(true)    
            {
                memset(buf, 0, BUFFER_SIZE);        
                int ret = recv(sockfd, buf, sizeof(buf)-1, 0);
                if(ret < 0)
                {
                    if((errno == EAGAIN) || (errno == EWOULDBLOCK))    
                    {break;}

                    close(sockfd);
                    break;
                }
                else if(ret == 0)
                {
                    close(sockfd);    
                }
                buf[ret] = '\0';
                cout<<"recv:"<<buf<<endl;
            }

            }
            //lt
            else
            {
                //接收一次数据。如系统内核有缓存数据，epoll_wait能再次处理
                memset(buf, 0, BUFFER_SIZE);    
                int ret = recv(sockfd, buf, sizeof(buf)-1, 0);
                if(ret < 0)
                {
                    close(sockfd);    
                    continue;
                }
                buf[ret] = '\0';
                cout<<"recv:"<<buf<<endl;
            }
        }
        else
        {
            //todo send    
        }
            
    }
}

int main(int argc, char** argv)
{
    //默认为LT模式，启动附加参数就启用ET模式。便于调试
    bool bET = false;
    if(argc > 1)
    {
        bET = true;    
    }
    const char* ip = "127.0.0.1";
    int port = 9999;

    //1.socket
    int listenfd = socket(PF_INET, SOCK_STREAM, 0);
    if(listenfd < 0)
    {
        cout<<"socket error"<<endl;
    }

    //2.bind
    sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr = htonl(INADDR_ANY);
    if(bind(listenfd, (sockaddr*)&addr, sizeof(addr)) == -1)
    {
        cout<<"bind error"<<endl;    
    }

    //3.listen
    if(listen(listenfd, 5) == -1)
    {cout<<"listen error"<<endl;}

    //4.epoll
    epoll_event events[MAX_EVENTS];
    //创建
    int epollfd = epoll_create(50);
    if(epollfd == -1)
    {cout<<"epoll_create error"<<endl;}
    //注册
    addfd(epollfd, listenfd, bET);
    
    //5.
    while(true)
    {
        //获取
        int ret = epoll_wait(epollfd, events, MAX_EVENTS, -1);    
        if(ret < 0)
        {cout<<"epoll_wait error"<<endl;}

        //处理
        epollwork(events, ret, epollfd, listenfd, bET);
    }

    close(listenfd);
    return 0;
}

//编译g++ -o epoll2 epoll2.cpp
//LT模式
//1.启动该服务，输入./epoll2
//2.ctrl+alt+f2,命令输入telnet 127.0.0.1 9999
//3.发送字符：aaaaabbbbbccccc  接收为:aaaaabbbb
//  发送字符: wjt              接收为:bcccccwjt

//ET模式
//1.启动该服务，输入./epoll2 et
//2.ctrl+alt+f2,命令输入telnet 127.0.0.1 9999
//3.发送字符：aaaaabbbbbccccc  接收为:aaaaabbbb
//                             接收为:bccccc