103 lines
3.1 KiB
Rust
103 lines
3.1 KiB
Rust
// Copyright 2015-2020 Parity Technologies (UK) Ltd.
|
|
// This file is part of Parity Ethereum.
|
|
|
|
// Parity Ethereum is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
|
|
// Parity Ethereum is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with Parity Ethereum. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
use shared;
|
|
use keccak::{keccak_256, H256};
|
|
|
|
use std::cell::Cell;
|
|
|
|
#[derive(Default)]
|
|
pub struct SeedHashCompute {
|
|
prev_epoch: Cell<u64>,
|
|
prev_seedhash: Cell<H256>,
|
|
}
|
|
|
|
impl SeedHashCompute {
|
|
#[inline]
|
|
fn reset_cache(&self) {
|
|
self.prev_epoch.set(0);
|
|
self.prev_seedhash.set([0u8; 32]);
|
|
}
|
|
|
|
#[inline]
|
|
pub fn hash_block_number(&self, block_number: u64) -> H256 {
|
|
self.hash_epoch(shared::epoch(block_number))
|
|
}
|
|
|
|
#[inline]
|
|
pub fn hash_epoch(&self, epoch: u64) -> H256 {
|
|
if epoch < self.prev_epoch.get() {
|
|
// can't build on previous hash if requesting an older block
|
|
self.reset_cache();
|
|
}
|
|
if epoch > self.prev_epoch.get() {
|
|
let seed_hash = SeedHashCompute::resume_compute_seedhash(
|
|
self.prev_seedhash.get(),
|
|
self.prev_epoch.get(),
|
|
epoch,
|
|
);
|
|
self.prev_seedhash.set(seed_hash);
|
|
self.prev_epoch.set(epoch);
|
|
}
|
|
self.prev_seedhash.get()
|
|
}
|
|
|
|
#[inline]
|
|
pub fn resume_compute_seedhash(mut hash: H256, start_epoch: u64, end_epoch: u64) -> H256 {
|
|
for _ in start_epoch..end_epoch {
|
|
keccak_256::inplace(&mut hash);
|
|
}
|
|
hash
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::SeedHashCompute;
|
|
|
|
#[test]
|
|
fn test_seed_compute_once() {
|
|
let seed_compute = SeedHashCompute::default();
|
|
let hash = [241, 175, 44, 134, 39, 121, 245, 239, 228, 236, 43, 160, 195, 152, 46, 7, 199, 5, 253, 147, 241, 206, 98, 43, 3, 104, 17, 40, 192, 79, 106, 162];
|
|
assert_eq!(seed_compute.hash_block_number(486382), hash);
|
|
}
|
|
|
|
#[test]
|
|
fn test_seed_compute_zero() {
|
|
let seed_compute = SeedHashCompute::default();
|
|
assert_eq!(seed_compute.hash_block_number(0), [0u8; 32]);
|
|
}
|
|
|
|
#[test]
|
|
fn test_seed_compute_after_older() {
|
|
let seed_compute = SeedHashCompute::default();
|
|
// calculating an older value first shouldn't affect the result
|
|
let _ = seed_compute.hash_block_number(50000);
|
|
let hash = [241, 175, 44, 134, 39, 121, 245, 239, 228, 236, 43, 160, 195, 152, 46, 7, 199, 5, 253, 147, 241, 206, 98, 43, 3, 104, 17, 40, 192, 79, 106, 162];
|
|
assert_eq!(seed_compute.hash_block_number(486382), hash);
|
|
}
|
|
|
|
#[test]
|
|
fn test_seed_compute_after_newer() {
|
|
let seed_compute = SeedHashCompute::default();
|
|
// calculating an newer value first shouldn't affect the result
|
|
let _ = seed_compute.hash_block_number(972764);
|
|
let hash = [241, 175, 44, 134, 39, 121, 245, 239, 228, 236, 43, 160, 195, 152, 46, 7, 199, 5, 253, 147, 241, 206, 98, 43, 3, 104, 17, 40, 192, 79, 106, 162];
|
|
assert_eq!(seed_compute.hash_block_number(486382), hash);
|
|
}
|
|
|
|
}
|