基於epoll的聊天室程式

                epoll相對於poll和select這兩個多工I/O模型更加的高效。epoll的函數很簡單，麻煩的地方在於水平出發和邊沿觸發。

               用張圖來說明下

             

ET(邊沿)只是在狀態反轉時觸發，比如從不可讀到可讀。而LT(水平)就是如果可讀，就會一直觸發。所以在使用ET的時候要做一些額外的處理，比如可讀的，一直把緩衝區讀完，進入不可讀狀態，下次來資料才會觸發。

下面貼出代碼，只是一個簡單的練習的例子

#ifndef SOCKETHEADS_H#define SOCKETHEADS_H#include <sys/types.h> #include <sys/socket.h>#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <unistd.h>#include <netinet/in.h>#include <fcntl.h>#include <netinet/in.h>#include <arpa/inet.h>#endif //SOCKETHEADS_H#ifndef EPOLL_H#define EPOLL_H#include <sys/epoll.h>#include <unistd.h>/** * @brief The Epoll class 對epoll的封裝 */class Epoll{public:    /**     *     */    enum EPOLL_OP {ADD = EPOLL_CTL_ADD, MOD = EPOLL_CTL_MOD, DEL = EPOLL_CTL_DEL};    /**     * 最大的串連數和最大的回傳事件數目     */    Epoll(int _max = 30, int maxevents = 20);    ~Epoll();    int create();    int add(int fd, epoll_event *event);    int mod(int fd, epoll_event *event);    int del(int fd, epoll_event *event);    void setTimeout(int timeout);    void setMaxEvents(int maxevents);    int wait();    const epoll_event* events() const;    const epoll_event& operator[](int index)    {        return backEvents[index];    }private:    bool isValid() const;    int max;    int epoll_fd;    int epoll_timeout;    int epoll_maxevents;    epoll_event *backEvents;};#endif //EPOLL_H#include "zepoll.h"Epoll::Epoll(int _max, int maxevents):max(_max),    epoll_fd(-1),    epoll_timeout(0),    epoll_maxevents(maxevents),    backEvents(0){}Epoll::~Epoll(){    if (isValid()) {        close(epoll_fd);    }    delete[] backEvents;}inlinebool Epoll::isValid() const{    return epoll_fd > 0;}inline void Epoll::setTimeout(int timeout){    epoll_timeout = timeout;}inline void Epoll::setMaxEvents(int maxevents){    epoll_maxevents = maxevents;}inlineconst epoll_event* Epoll::events() const{    return backEvents;}int Epoll::create(){    epoll_fd = ::epoll_create(max);    if (isValid()) {        backEvents = new epoll_event[epoll_maxevents];    }    return epoll_fd;}int Epoll::add(int fd, epoll_event *event){    if (isValid()) {        return ::epoll_ctl(epoll_fd, ADD, fd, event);    }    return -1;}int Epoll::mod(int fd, epoll_event *event){    if (isValid()) {        return ::epoll_ctl(epoll_fd, MOD, fd, event);    }    return -1;}int Epoll::del(int fd, epoll_event *event){    if (isValid()) {        return ::epoll_ctl(epoll_fd, DEL, fd, event);    }    return -1;}int Epoll::wait(){    if (isValid()) {        return ::epoll_wait(epoll_fd, backEvents, epoll_maxevents, epoll_timeout);    }    return -1;}/********************************************************************* author 周翔* e-mail 604487178@qq.com* blog http://blog.csdn.net/zhx6044**********************************************************************/#ifndef TASK_H#define TASK_H#include <string>#include <socketheads.h>/** * @brief The Task class 任務類 */class Task{public:    typedef enum {CONNECT = 0, DISCONNECT, TALKING} TASKFLAG;    Task(const std::string &message, TASKFLAG flag = TALKING);    const std::string& getMessage() const;    TASKFLAG getFlag() const;    void setIP(in_addr _ip);    int getS_fd() const;    void setS_fd(int _fd);    std::string getData() const;private:    std::string m_message;    TASKFLAG m_flag;    in_addr ip;    int s_fd;};#endif // TASK_H/********************************************************************* author 周翔* e-mail 604487178@qq.com* blog http://blog.csdn.net/zhx6044**********************************************************************/#include "task.h"Task::Task(const std::string &message, TASKFLAG flag):    m_message(message),    m_flag(flag){}const std::string& Task::getMessage() const{    return m_message;}Task::TASKFLAG Task::getFlag() const{    return m_flag;}void Task::setIP(in_addr _ip){    ip = _ip;}int Task::getS_fd() const{    return s_fd;}void Task::setS_fd(int _fd){    s_fd = _fd;}std::string Task::getData() const{    std::string re;    if (m_flag == CONNECT) {        re = ::inet_ntoa(ip) + std::string("----->") + "CONNECT!    " + m_message;    } else {        if (m_flag == DISCONNECT) {            re = ::inet_ntoa(ip) + std::string("----->") + "DISCONNECT   " + m_message;;        } else {            re = ::inet_ntoa(ip) + std::string("----->Talk:") + m_message;        }    }    return re;}#ifndef EPOLL_SERVER_H#define EPOLL_SERVER_H#include <map>#include <list>#include "zepoll.h"#include "socketheads.h"#include "task.h"typedef std::pair<int, in_addr> FDtoIP;/** * @brief The Epoll_server class 伺服器 */class Epoll_server{public:    Epoll_server(int port);    ~Epoll_server();    int bind();    int listen();    void poweroff();    bool states() const;private:    enum  {BLOCKLOG = 5};    bool isValid() const;    int acceptSocketEpoll();    int readSocketEpoll(const epoll_event &ev);    int writeSocketEpoll(const epoll_event &ev);    void doTask(const Task &t);    int _port;    int server_socket_fd;    Epoll *_epoll;    sockaddr_in server_addr;    sockaddr_in client_addr;    epoll_event m_event;    bool on;    static int setNonblocking(int socket_fd);    std::list<FDtoIP> fd_IP;};#endif //EPOLL_SERVER_H#include "epoll_server.h"#include <iostream>//static char welcom[] = "welcom to my epoll_server";//static char sorry[] = "Sorry! This is a simple demo,so not any function!";//static char buf[BUFSIZ];Epoll_server::Epoll_server(int port):_port(port),    server_socket_fd(-1),    _epoll(0),    on(true){}Epoll_server::~Epoll_server(){    if (isValid()) {        ::close(server_socket_fd);    }    delete _epoll;}inlinebool Epoll_server::isValid() const{    return server_socket_fd > 0;}inlinevoid Epoll_server::poweroff(){    on = false;}inlinebool Epoll_server::states() const{    return on;}int Epoll_server::setNonblocking(int socket_fd){    int opts;    opts = fcntl(socket_fd, F_GETFL);    if (opts < 0) {        return -1;    } else    {        opts = opts | O_NONBLOCK;        if (fcntl(socket_fd, F_SETFL, opts) < 0) {            return -1;        }    }    return 0;}void Epoll_server::doTask(const Task &t){    std::list<FDtoIP>::iterator ite = fd_IP.begin();    std::list<FDtoIP>::iterator ite1 = fd_IP.end();    for (;ite != fd_IP.end();++ite) {        if ((*ite).first != t.getS_fd()) {            memset(&m_event, '\0', sizeof(m_event));            m_event.events = EPOLLOUT | EPOLLET;            Task *c = new Task(t);            c->setS_fd((*ite).first);            m_event.data.ptr = static_cast<void*>(c);            _epoll->mod((*ite).first, &m_event);        } else {            ite1 = ite;        }    }    if (t.getFlag() == Task::DISCONNECT) {        if (ite1 != fd_IP.end()) {            fd_IP.erase(ite1);        }    }}/** * @brief Epoll_server::acceptSocketEpoll 有使用者接入 * @return */int Epoll_server::acceptSocketEpoll(){    socklen_t len = sizeof(struct sockaddr_in);    int connect_fd;    while ((connect_fd = ::accept(server_socket_fd,                                  (struct sockaddr*)(&client_addr), &len)) > 0) {        if (setNonblocking(connect_fd) < 0) {            ::close(connect_fd);            continue;        }        m_event.data.fd = connect_fd;        m_event.events = EPOLLIN | EPOLLET;        if (_epoll->add(connect_fd, &m_event) < 0) {            ::close(connect_fd);            continue;        } else {            fd_IP.push_back(FDtoIP(connect_fd, client_addr.sin_addr));            Task t("come in", Task::CONNECT);            t.setIP(client_addr.sin_addr);            t.setS_fd(connect_fd);            doTask(t);        }    }    if (connect_fd == -1 && errno != EAGAIN && errno != ECONNABORTED            && errno != EPROTO && errno !=EINTR) {        return -1;    }    return 0;}int Epoll_server::readSocketEpoll(const epoll_event &ev){    int n = 0;    int nread = 0;    char buf[BUFSIZ]={'\0'};    while ((nread = ::read(ev.data.fd, buf + n, BUFSIZ-1)) > 0) {        n += nread;    }    if (nread == -1 && errno != EAGAIN) {        return -1;    }    std::list<FDtoIP>::iterator ite = fd_IP.begin();    for (;ite != fd_IP.end();++ite) {        if ((*ite).first == ev.data.fd) {            break;        }    }    if (nread == 0) {        strcpy(buf, " disconet  left ");        Task t(buf,Task::DISCONNECT);        t.setIP(client_addr.sin_addr);        t.setS_fd((*ite).first);        doTask(t);    } else {        Task t(buf,Task::TALKING);        t.setIP(client_addr.sin_addr);        t.setS_fd((*ite).first);        doTask(t);    }    //    Task *t = new Task(buf,Task::DISCONNECT);    //    t->setIP((*ite).second);    //    t->setS_fd((*ite).first);    // m_event.data.fd = ev.data.fd;    // m_event.events = ev.events;    return 0;//_epoll->mod(m_event.data.fd, &m_event);}int Epoll_server::writeSocketEpoll(const epoll_event &ev){    Task *t = static_cast<Task*>(ev.data.ptr);    const char* buf = t->getData().data();    int nwrite = 0, data_size = strlen(buf);    int fd = t->getS_fd();    int n = data_size;    delete t;    while (n > 0) {        nwrite = ::write(fd, buf + data_size - n, n);        if (nwrite < 0) {            if (nwrite == -1 && errno != EAGAIN) {                return -1;            }            break;        }        n -= nwrite;    }    memset(&m_event, '\0', sizeof(m_event));    // m_event.events &= ~EPOLLOUT;    m_event.events = EPOLLIN | EPOLLET;    m_event.data.fd = fd;    if (_epoll->mod(fd, &m_event) < 0) {        ::close(m_event.data.fd);        return -1;    }    return 0;}/** * @brief Epoll_server::bind * @return */int Epoll_server::bind(){    server_socket_fd = socket(AF_INET, SOCK_STREAM, 0);    if (server_socket_fd < 0) {        return -1;    }    setNonblocking(server_socket_fd);    _epoll = new Epoll();    if (_epoll->create() < 0) {        return -1;    }    memset(&m_event, '\0', sizeof(m_event));    m_event.data.fd = server_socket_fd;    m_event.events = EPOLLIN | EPOLLET;    _epoll->add(server_socket_fd, &m_event);    memset(&server_addr, 0 ,sizeof(server_addr));    server_addr.sin_family = AF_INET;    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);    server_addr.sin_port = htons(_port);    return ::bind(server_socket_fd, (struct sockaddr*)(&server_addr), sizeof(struct sockaddr));}int Epoll_server::listen(){    if (isValid()) {        if (::listen(server_socket_fd, BLOCKLOG) < 0) {            return -1;        } else {            int num;            while (on) {                num = _epoll->wait();                for (int i = 0;i < num;++i) {                    /**                     * 接受串連的串連，把她加入到epoll中                     */                    if ((*_epoll)[i].data.fd == server_socket_fd) {                        if (acceptSocketEpoll() < 0) {                            break;                        }                        continue;                    }                    /**                     * EPOLLIN event                     */                    if ((*_epoll)[i].events & EPOLLIN) {                        if (readSocketEpoll((*_epoll)[i]) < 0) {                            break;                        }                        continue;                    }                    /**                     * EPOLLOUT event                     */                    if ((*_epoll)[i].events & EPOLLOUT) {                        if (writeSocketEpoll((*_epoll)[i]) < 0) {                            break;                        }                    }                }            }        }    }    return -1;}#include "epoll_server.h"#include <iostream>int main(int /*argc*/, char const **/*argv[]*/){    std::cout << "server" << std::endl;    Epoll_server s(18090);    if (s.bind() < 0) {        return -1;    }    return s.listen();}

用戶端用qt簡單的寫了一個

需要用戶端程式的在這裡

http://pan.baidu.com/share/link?shareid=1711493932&uk=3507221172