Function mixDigest

app/redis-6.2.6/src/debug.c:112–120

This function instead of just computing the SHA1 and xoring it * against digest, also perform the digest of "digest" itself and * replace the old value with the new one. * * So the final digest will be: * * digest = SHA1(digest xor SHA1(data)) * * This function is used every time we want to preserve the order so * that digest(a,b,c,d) will be different than digest(b,c,d,a) * * Also note

 * will lead to a different digest compared to "fo", "obar".
 */
void mixDigest(unsigned char *digest, void *ptr, size_t len) {
    SHA1_CTX ctx;
    char *s = ptr;

    xorDigest(digest,s,len);
    SHA1Init(&ctx);
    SHA1Update(&ctx,digest,20);
    SHA1Final(digest,&ctx);
}

void mixStringObjectDigest(unsigned char *digest, robj *o) {
    o = getDecodedObject(o);