void appendCommand(client *c) {
    size_t totlen;
    robj *o, *append;

    o = lookupKeyWrite(c->db,c->argv[1]);
    if (o == NULL) {
        /* Create the key */
        c->argv[2] = tryObjectEncoding(c->argv[2]);
        dbAdd(c->db,c->argv[1],c->argv[2]);
        incrRefCount(c->argv[2]);
        totlen = stringObjectLen(c->argv[2]);
    } else {
        /* Key exists, check type */
        if (checkType(c,o,OBJ_STRING))
            return;

        /* "append" is an argument, so always an sds */
        append = c->argv[2];
        totlen = stringObjectLen(o)+sdslen(append->ptr);
        if (checkStringLength(c,totlen) != C_OK)
            return;

        /* Append the value */
        o = dbUnshareStringValue(c->db,c->argv[1],o);
        o->ptr = sdscatlen(o->ptr,append->ptr,sdslen(append->ptr));
        totlen = sdslen(o->ptr);
    }
    signalModifiedKey(c,c->db,c->argv[1]);
    notifyKeyspaceEvent(NOTIFY_STRING,"append",c->argv[1],c->db->id);
    server.dirty++;
    addReplyLongLong(c,totlen);
}
void appendCommand(client *c) {
    size_t totlen;
    robj *o, *append;

    o = lookupKeyWrite(c->db,c->argv[1]);
    if (o == NULL) {
         
        c->argv[2] = tryObjectEncoding(c->argv[2]);
        dbAdd(c->db,c->argv[1],c->argv[2]);
        incrRefCount(c->argv[2]);
        totlen = stringObjectLen(c->argv[2]);
    } else {
         
        if (checkType(c,o,OBJ_STRING))
            return;

         
        append = c->argv[2];
        totlen = stringObjectLen(o)+sdslen(append->ptr);
        if (checkStringLength(c,totlen) != C_OK)
            return;

         
        o = dbUnshareStringValue(c->db,c->argv[1],o);
        o->ptr = sdscatlen(o->ptr,append->ptr,sdslen(append->ptr));
        totlen = sdslen(o->ptr);
    }
    signalModifiedKey(c,c->db,c->argv[1]);
    notifyKeyspaceEvent(NOTIFY_STRING,"append",c->argv[1],c->db->id);
    server.dirty++;
    addReplyLongLong(c,totlen);
}