基于epoll的聊天室程序

epoll相对于poll和select这两个多路复用的I/O模型更加的高效。epoll的函数很简单，麻烦的地方在于水平触发和边沿触发。

用张图来说明下

ET(边沿)只是在状态反转时触发，比如从不可读到可读。而LT(水平)就是如果可读，就会一直触发。所以在使用ET的时候要做一些额外的处理，比如可读的，一直把缓冲区读完，进入不可读状态，下次来数据才会触发。

下面贴出代码，只是一个简单的练习的例子
socketheads.h

 

 

 

 

 

C++

 

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#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

zepoll.h

 

 

 

 

 

C++

 

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#ifndef EPOLL_H #define EPOLL_H   #include <sys/epoll.h> #include <unistd.h>     /** * @brief The Epoll class 对epoll的封装 */ class Epoll { public:     /**      *      */     enum EPOLL_OP {ADD = EPOLL_CTL_ADD, MOD = EPOLL_CTL_MOD, DEL = EPOLL_CTL_DEL};     /**      * 最大的连接数和最大的回传事件数      */     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

zepoll.cpp

 

 

 

 

 

C++

 

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#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; }     inline bool 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; }   inline const 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; }

task.h

 

 

 

 

 

C++

 

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/******************************************************************** * 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 任务类 */ 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

task.cpp

 

 

 

 

 

C++

 

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/******************************************************************** * 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; }

epoll_server.h

 

 

 

 

 

C++

 

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#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 服务器 */ 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

epoll_server.cpp

 

 

 

 

 

C++

 

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#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;   }     inline bool Epoll_server::isValid() const {     return server_socket_fd > 0; }     inline void Epoll_server::poweroff() {     on = false; }       inline bool 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, '', 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 有用户接入 * @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]={''};     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, '', 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, '', 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) {                     /**                      * 接受连接的连接，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; }

main.cpp

 

 

 

 

 

C++

 

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#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(); }

客户端用qt简单的写了一个

客户端服务端代码：epoll_chatroom.zip

http://love.junzimu.com/archives/2660