Function zaddGenericCommand

app/redis-6.2.6/src/t_zset.c:1720–1846

This generic command implements both ZADD and ZINCRBY. */

/* This generic command implements both ZADD and ZINCRBY. */
void zaddGenericCommand(client *c, int flags) {
    static char *nanerr = "resulting score is not a number (NaN)";
    robj *key = c->argv[1];
    robj *zobj;
    sds ele;
    double score = 0, *scores = NULL;
    int j, elements, ch = 0;
    int scoreidx = 0;
    /* The following vars are used in order to track what the command actually
     * did during the execution, to reply to the client and to trigger the
     * notification of keyspace change. */
    int added = 0;      /* Number of new elements added. */
    int updated = 0;    /* Number of elements with updated score. */
    int processed = 0;  /* Number of elements processed, may remain zero with
                           options like XX. */

    /* Parse options. At the end 'scoreidx' is set to the argument position
     * of the score of the first score-element pair. */
    scoreidx = 2;
    while(scoreidx < c->argc) {
        char *opt = c->argv[scoreidx]->ptr;
        if (!strcasecmp(opt,"nx")) flags |= ZADD_IN_NX;
        else if (!strcasecmp(opt,"xx")) flags |= ZADD_IN_XX;
        else if (!strcasecmp(opt,"ch")) ch = 1; /* Return num of elements added or updated. */
        else if (!strcasecmp(opt,"incr")) flags |= ZADD_IN_INCR;
        else if (!strcasecmp(opt,"gt")) flags |= ZADD_IN_GT;
        else if (!strcasecmp(opt,"lt")) flags |= ZADD_IN_LT;
        else break;
        scoreidx++;
    }

    /* Turn options into simple to check vars. */
    int incr = (flags & ZADD_IN_INCR) != 0;
    int nx = (flags & ZADD_IN_NX) != 0;
    int xx = (flags & ZADD_IN_XX) != 0;
    int gt = (flags & ZADD_IN_GT) != 0;
    int lt = (flags & ZADD_IN_LT) != 0;

    /* After the options, we expect to have an even number of args, since
     * we expect any number of score-element pairs. */
    elements = c->argc-scoreidx;
    if (elements % 2 || !elements) {
        addReplyErrorObject(c,shared.syntaxerr);
        return;
    }
    elements /= 2; /* Now this holds the number of score-element pairs. */

    /* Check for incompatible options. */
    if (nx && xx) {
        addReplyError(c,
            "XX and NX options at the same time are not compatible");
        return;
    }
    
    if ((gt && nx) || (lt && nx) || (gt && lt)) {
        addReplyError(c,
            "GT, LT, and/or NX options at the same time are not compatible");
        return;