Function xorObjectDigest

app/redis-6.2.6/src/debug.c:136–265

This function computes the digest of a data structure stored in the * object 'o'. It is the core of the DEBUG DIGEST command: when taking the * digest of a whole dataset, we take the digest of the key and the value * pair, and xor all those together. * * Note that this function does not reset the initial 'digest' passed, it * will continue mixing this object digest to anything that was alrea

 * will continue mixing this object digest to anything that was already
 * present. */
void xorObjectDigest(redisDb *db, robj *keyobj, unsigned char *digest, robj *o) {
    uint32_t aux = htonl(o->type);
    mixDigest(digest,&aux,sizeof(aux));
    long long expiretime = getExpire(db,keyobj);
    char buf[128];

    /* Save the key and associated value */
    if (o->type == OBJ_STRING) {
        mixStringObjectDigest(digest,o);
    } else if (o->type == OBJ_LIST) {
        listTypeIterator *li = listTypeInitIterator(o,0,LIST_TAIL);
        listTypeEntry entry;
        while(listTypeNext(li,&entry)) {
            robj *eleobj = listTypeGet(&entry);
            mixStringObjectDigest(digest,eleobj);
            decrRefCount(eleobj);
        }
        listTypeReleaseIterator(li);
    } else if (o->type == OBJ_SET) {
        setTypeIterator *si = setTypeInitIterator(o);
        sds sdsele;
        while((sdsele = setTypeNextObject(si)) != NULL) {
            xorDigest(digest,sdsele,sdslen(sdsele));
            sdsfree(sdsele);
        }
        setTypeReleaseIterator(si);
    } else if (o->type == OBJ_ZSET) {
        unsigned char eledigest[20];

        if (o->encoding == OBJ_ENCODING_ZIPLIST) {
            unsigned char *zl = o->ptr;
            unsigned char *eptr, *sptr;
            unsigned char *vstr;
            unsigned int vlen;
            long long vll;
            double score;

            eptr = ziplistIndex(zl,0);
            serverAssert(eptr != NULL);
            sptr = ziplistNext(zl,eptr);
            serverAssert(sptr != NULL);

            while (eptr != NULL) {
                serverAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
                score = zzlGetScore(sptr);

                memset(eledigest,0,20);
                if (vstr != NULL) {
                    mixDigest(eledigest,vstr,vlen);
                } else {
                    ll2string(buf,sizeof(buf),vll);
                    mixDigest(eledigest,buf,strlen(buf));
                }

                snprintf(buf,sizeof(buf),"%.17g",score);
                mixDigest(eledigest,buf,strlen(buf));
                xorDigest(digest,eledigest,20);
                zzlNext(zl,&eptr,&sptr);