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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | #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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | #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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 | #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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 | /******************************************************************** * 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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 | /******************************************************************** * 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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | #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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 | #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
1 2 3 4 5 6 7 8 9 10 11 12 | #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
原文链接: https://www.cnblogs.com/findumars/p/4973114.html
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