zebra/zebra-chain/src/block.rs

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//! Definitions of block datastructures.
use chrono::{DateTime, Utc};
use std::io;
use crate::merkle_tree::MerkleTree;
use crate::serialization::{SerializationError, ZcashDeserialize, ZcashSerialize};
use crate::sha256d_writer::Sha256dWriter;
use crate::transaction::Transaction;
/// A SHA-256d hash of a BlockHeader.
///
/// This is useful when one block header is pointing to its parent
/// block header in the block chain. ⛓️
pub struct BlockHash([u8; 32]);
impl From<BlockHeader> for BlockHash {
fn from(block_header: BlockHeader) -> Self {
let mut hash_writer = Sha256dWriter::default();
block_header
.zcash_serialize(&mut hash_writer)
.expect("Block headers must serialize.");
Self(hash_writer.finish())
}
}
/// A SHA-256d hash of the root node of a merkle tree of SHA256-d
/// hashed transactions in a block.
pub struct MerkleRootHash([u8; 32]);
impl From<MerkleTree<Transaction>> for MerkleRootHash {
fn from(merkle_tree: MerkleTree<Transaction>) -> Self {
let mut hash_writer = Sha256dWriter::default();
merkle_tree
.zcash_serialize(&mut hash_writer)
.expect("The merkle tree of transactions must serialize.");
Self(hash_writer.finish())
}
}
/// Block header
pub struct BlockHeader {
/// A SHA-256d hash in internal byte order of the previous blocks
/// header. This ensures no previous block can be changed without
/// also changing this blocks header .
previous_block_hash: BlockHash,
/// A SHA-256d hash in internal byte order. The merkle root is
/// derived from the SHA256d hashes of all transactions included
/// in this block as assembled in a binary tree, ensuring that
/// none of those transactions can be modied without modifying the
/// header.
merkle_root_hash: [u8; 32],
/// [Sapling onward] The root LEBS2OSP256(rt) of the Sapling note
/// commitment tree corresponding to the nal Sapling treestate of
/// this block.
// TODO: replace type with custom SaplingRoot or similar type
// hash_final_sapling_root: SaplingRootHash,
/// The block timestamp is a Unix epoch time (UTC) when the miner
/// started hashing the header (according to the miner).
time: DateTime<Utc>,
/// An encoded version of the target threshold this blocks header
/// hash must be less than or equal to, in the same nBits format
/// used by Bitcoin.
///
/// For a block at block height height, bits MUST be equal to
/// ThresholdBits(height).
///
/// [Bitcoin-nBits](https://bitcoin.org/en/developer-reference#target-nbits)
// pzec has their own wrapper around u32 for this field:
// https://github.com/ZcashFoundation/zebra/blob/master/zebra-primitives/src/compact.rs
bits: u32,
/// An arbitrary field that miners can change to modify the header
/// hash in order to produce a hash less than or equal to the
/// target threshold.
nonce: [u8; 32],
/// The Equihash solution.
// The solution size when serialized should be in bytes ('always 1344').
solution: [u8; 1344],
}
impl BlockHeader {
/// Get the SHA-256d hash in internal byte order of this block header.
pub fn hash(&self) -> [u8; 32] {
unimplemented!();
}
}
impl ZcashSerialize for BlockHeader {
fn zcash_serialize<W: io::Write>(&self, writer: W) -> Result<(), SerializationError> {
unimplemented!();
}
}
impl ZcashDeserialize for BlockHeader {
fn zcash_deserialize<R: io::Read>(reader: R) -> Result<Self, SerializationError> {
unimplemented!();
}
}
/// A block in your blockchain.
pub struct Block {
/// First 80 bytes of the block as defined by the encoding used by
/// "block" messages.
pub header: BlockHeader,
/// Block transactions.
pub transactions: Vec<Transaction>,
}