This extracts the `difficulty` module from `block` and the
`equihash_solution` module from the crate root. The PoW calculations
are significantly more complicated than the other block code and pretty
dissimilar from it, so it makes more sense to create a common proof of
work module.
The `EquihashSolution` and `EQUIHASH_SOLUTION_SIZE` are renamed to
`equihash::Solution` and `equihash::SOLUTION_SIZE` and imported that
way, except in `block/header.rs`, to avoid a conflict with the
`equihash` crate. In the future it would be better to encapsulate the
equihash solution check into the `equihash::Solution` type so that
callers only need to import our `work::equihash`.
The test organization leaves a little to be desired but I think that
this can be improved as we fill out the proof of work implementation.
This changes the `light_client_root_hash` field to `light_client_root_bytes` to
hint that it's unparsed, and makes it public to match the rest of the
`BlockHeader` fields. The `LightClientRootHash` serialization methods are
hidden from the public API, so that the `LightClientRootHash` has to be
constructed by the method on the `Block`.
The Heartwood upgrade changes the meaning of the hashFinalSaplingRoot to
hashLightClientRoot. Since we don't know the network upgrade heights in
zebra-chain, we just use [u8; 32] for now.
* create hash submodule for block
* create header submodule for block
* create serialize submodule for block
* add newline to hash.rs (fmt)
* Update zebra-chain/src/block/tests.rs
Co-authored-by: Jane Lusby <jlusby42@gmail.com>
Co-authored-by: Henry de Valence <hdevalence@hdevalence.ca>
Co-authored-by: Jane Lusby <jlusby42@gmail.com>