Unix/Linux 编程:网络编程之 epoll与Reactor

在上一篇文章中实现了epoll的非阻塞IO的服务端程序

可是如果实际应用中需要注册大量事件，一个超长的if代码块会严重降低代码的可读性和管理

因此参考了 Reactor模型的实现改写了epoll服务器。讲所有的事件处理函数都写成回调函数的形式。这里注意几个参数传递时候的坑。

/* Server based on EPOLL */
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define BUFFER_LENGTH   1024

struct sockitem {
    int epollfd;
    int sockfd;
    int (*callback)(int fd, int events, void* arg);
};

int recv_cb(int fd, int events, void* arg) {
    if (!(events & EPOLLIN) || arg == NULL)
        return -1;
    printf("trigger recv_cb\n");
    struct epoll_event* ev = (struct epoll_event*)arg;
    struct sockitem* si = (struct sockitem*)ev->data.ptr;

    int clientfd = si->sockfd;
    int epoll_fd = si->epollfd;

    char buffer[BUFFER_LENGTH] = { 0 };
    int ret = recv(clientfd, buffer, BUFFER_LENGTH, 0);
    if (ret < 0) {
        if (errno == EAGAIN || errno == EWOULDBLOCK) {
            printf("read all data\n");
        }
        close(clientfd);
        ev->events = EPOLLIN | EPOLLET;
        ev->data.fd = clientfd;
        ev->data.ptr = NULL;
        free(si);
        epoll_ctl(epoll_fd, EPOLL_CTL_DEL, clientfd, ev);
    }
    else if (ret == 0) {
        printf(" disconnect clientfd:%d\n", clientfd);

        close(clientfd);
        ev->events = EPOLLIN | EPOLLET;
        ev->data.fd = clientfd;
        ev->data.ptr = NULL;
        free(si);
        epoll_ctl(epoll_fd, EPOLL_CTL_DEL, clientfd, ev);
        return 0;
    }
    else {
        printf("Recv: %s, %d Bytes\n", buffer, ret);
        if (send(clientfd, "Hello, you are connected!\n", 26, 0)
            == -1) {
            // send data error maybe some network issue.
            perror("send error");
            close(clientfd);
        }
    }
}

// callback handler for accept events of the sockfd.
int accept_cb(int fd, int events, void* arg) {
    if (!(events & EPOLLIN) || arg == NULL)
        return -1;
    printf("trigger accept_cb\n");
    struct epoll_event* ev = (struct epoll_event*)arg;