Function scanLaterList

app/redis-6.2.6/src/defrag.c:444–485

returns 0 if no more work needs to be been done, and 1 if time is up and more work is needed. */

/* returns 0 if no more work needs to be been done, and 1 if time is up and more work is needed. */
long scanLaterList(robj *ob, unsigned long *cursor, long long endtime, long long *defragged) {
    quicklist *ql = ob->ptr;
    quicklistNode *node;
    long iterations = 0;
    int bookmark_failed = 0;
    if (ob->type != OBJ_LIST || ob->encoding != OBJ_ENCODING_QUICKLIST)
        return 0;

    if (*cursor == 0) {
        /* if cursor is 0, we start new iteration */
        node = ql->head;
    } else {
        node = quicklistBookmarkFind(ql, "_AD");
        if (!node) {
            /* if the bookmark was deleted, it means we reached the end. */
            *cursor = 0;
            return 0;
        }
        node = node->next;
    }

    (*cursor)++;
    while (node) {
        (*defragged) += activeDefragQuickListNode(ql, &node);
        server.stat_active_defrag_scanned++;
        if (++iterations > 128 && !bookmark_failed) {
            if (ustime() > endtime) {
                if (!quicklistBookmarkCreate(&ql, "_AD", node)) {
                    bookmark_failed = 1;
                } else {
                    ob->ptr = ql; /* bookmark creation may have re-allocated the quicklist */
                    return 1;
                }
            }
            iterations = 0;
        }
        node = node->next;
    }
    quicklistBookmarkDelete(ql, "_AD");
    *cursor = 0;
    return bookmark_failed? 1: 0;
}

typedef struct {
    zset *zs;