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出发和边沿触发。
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
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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
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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
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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
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/******************************************************************** * author 周翔 * e-mail [email protected] * 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
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/******************************************************************** * author 周翔 * e-mail [email protected] * 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
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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
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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, '\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]={'\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
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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
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