Function isInvalidReason

Check the validity of a new pre-image information

string isInvalidReason (
  in ref const(PreImageInfo) newer,
  in ref const(PreImageInfo) previous
) nothrow @safe;

Pre-image infomation is considered valid if: - The keys for enrollment in two pieces of pre-image information are same - Height for a pre-image is greater than height for a current image - A current image is same as n times hashed value of a pre-image (n = difference of two heights).

Parameters

NameDescription
newer The pre-image information to check
previous The previous pre-image information

Returns

null if the pre-image is valid, otherwise a string explaining the reason it is invalid.

Example

test for validity of pre-image 

auto params = new immutable(ConsensusParams)(2000);

import agora.common.Types;

Hash[] preimages;
preimages ~= hashFull(Scalar.random());
foreach (i; 0 .. params.ValidatorCycle)
    preimages ~= hashFull(preimages[i]);
reverse(preimages);

PreImageInfo prev_image = PreImageInfo(hashFull("abc"), preimages[0], Height(0));

// valid pre-image
PreImageInfo new_image = PreImageInfo(hashFull("abc"), preimages[100], Height(100));
assert(new_image.isValid(prev_image));

// invalid pre-image with wrong UTXO
new_image = PreImageInfo(hashFull("xyz"), preimages[100], Height(100));
assert(!new_image.isValid(prev_image));

// invalid pre-image with wrong height number
new_image = PreImageInfo(hashFull("abc"), preimages[1], Height(3));
assert(!new_image.isValid(prev_image));

// invalid pre-image with wrong hash value
new_image = PreImageInfo(hashFull("abc"), preimages[101], Height(100));
assert(!new_image.isValid(prev_image));