Redis源码分析（二十一）--- anet网络通信的封装 - c++编程基础

还是非常全面的。在对地址做resolve解析的时候就考虑到了这个问题:

/* anetGenericResolve() is called by anetResolve() and anetResolveIP() to
 * do the actual work. It resolves the hostname "host" and set the string
 * representation of the IP address into the buffer pointed by "ipbuf".
 *
 * If flags is set to ANET_IP_ONLY the function only resolves hostnames
 * that are actually already IPv4 or IPv6 addresses. This turns the function
 * into a validating / normalizing function. */
/* 解析的泛型方法，可以根据条件解析host主机名或IP地址 */
int anetGenericResolve(char *err, char *host, char *ipbuf, size_t ipbuf_len,
                       int flags)
{
    struct addrinfo hints, *info;
    int rv;

    memset(&hints,0,sizeof(hints));
    if (flags & ANET_IP_ONLY) hints.ai_flags = AI_NUMERICHOST;
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;  /* specify socktype to avoid dups */

	//解析hostName
    if ((rv = getaddrinfo(host, NULL, &hints, &info)) != 0) {
        anetSetError(err, "%s", gai_strerror(rv));
        return ANET_ERR;
    }
    
    //根据类型解析ipV4的地址还是ipV6的地址
    if (info->ai_family == AF_INET) {
        struct sockaddr_in *sa = (struct sockaddr_in *)info->ai_addr;
        inet_ntop(AF_INET, &(sa->sin_addr), ipbuf, ipbuf_len);
    } else {
        struct sockaddr_in6 *sa = (struct sockaddr_in6 *)info->ai_addr;
        inet_ntop(AF_INET6, &(sa->sin6_addr), ipbuf, ipbuf_len);
    }

    freeaddrinfo(info);
    return ANET_OK;
}

还有一些常见的方法，与我们平时写代码时用的手法基本一样，比如accept()的方法：

/* socket连接操作 */
static int anetGenericAccept(char *err, int s, struct sockaddr *sa, socklen_t *len) {
    int fd;
    while(1) {
    	//通过while循环等待连接
        fd = accept(s,sa,len);
        if (fd == -1) {
            if (errno == EINTR)
                continue;
            else {
                anetSetError(err, "accept: %s", strerror(errno));
                return ANET_ERR;
            }
        }
        break;
    }
    return fd;
}

Redis源码分析（二十一）--- anet网络通信的封装(二)