Redis的Client设计

本文原创为freas_1990，转载请标明出处：http://blog.csdn.net/freas_1990/article/details/25432823

Redis的client设计如下：

/* With multiplexing we need to take per-clinet state.
 * Clients are taken in a liked list. */
typedef struct redisClient {
    int fd;
    redisDb *db;
    int dictid;
    sds querybuf;
    robj **argv, **mbargv;
    int argc, mbargc;
    int bulklen;            /* bulk read len. -1 if not in bulk read mode */
    int multibulk;          /* multi bulk command format active */
    list *reply;
    int sentlen;
    time_t lastinteraction; /* time of the last interaction, used for timeout */
    int flags;              /* REDIS_CLOSE | REDIS_SLAVE | REDIS_MONITOR */
    int slaveseldb;         /* slave selected db, if this client is a slave */
    int authenticated;      /* when requirepass is non-NULL */
    int replstate;          /* replication state if this is a slave */
    int repldbfd;           /* replication DB file descriptor */
    long repldboff;          /* replication DB file offset */
    off_t repldbsize;       /* replication DB file size */
} redisClient;

在accpet后，开始创建一个client。

代码如下：

static client createClient(void) {
    client c = zmalloc(sizeof(struct _client));
    char err[ANET_ERR_LEN];

    c->fd = anetTcpNonBlockConnect(err,config.hostip,config.hostport);
    if (c->fd == ANET_ERR) {
        zfree(c);
        fprintf(stderr,"Connect: %s\n",err);
        return NULL;
    }
    anetTcpNoDelay(NULL,c->fd);
    c->obuf = sdsempty();
    c->ibuf = sdsempty();
    c->mbulk = -1;
    c->readlen = 0;
    c->written = 0;
    c->totreceived = 0;
    c->state = CLIENT_CONNECTING;
    aeCreateFileEvent(config.el, c->fd, AE_WRITABLE, writeHandler, c);
    config.liveclients++;
    listAddNodeTail(config.clients,c);
    return c;
}

窃以为，以下代码写的有点shit。

   listAddNodeTail(config.clients,c);

这个函数既然命名为createclient就该做create的事，而把listaddnodetail放到外层函数里面实现。

既然在createclient函数里实现了add功能，又再返回一个c指针到外层函数实现超出链接数判断，显得有些畸形。

同学们，你们觉得呢？

Redis的Client设计