openethereum/ethash/src/lib.rs
2016-02-29 19:30:13 +01:00

120 lines
3.6 KiB
Rust

// Copyright 2015, 2016 Ethcore (UK) Ltd.
// This file is part of Parity.
// Parity 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 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. If not, see <http://www.gnu.org/licenses/>.
//! Ethash implementation
//! See https://github.com/ethereum/wiki/wiki/Ethash
extern crate primal;
extern crate sha3;
#[macro_use]
extern crate log;
mod compute;
use std::mem;
use compute::Light;
pub use compute::{get_seedhash, quick_get_difficulty, H256, ProofOfWork, ETHASH_EPOCH_LENGTH};
use std::sync::{Arc, Mutex};
struct LightCache {
recent_epoch: Option<u64>,
recent: Option<Arc<Light>>,
prev_epoch: Option<u64>,
prev: Option<Arc<Light>>,
}
/// Light/Full cache manager.
pub struct EthashManager {
cache: Mutex<LightCache>,
}
impl EthashManager {
/// Create a new new instance of ethash manager
pub fn new() -> EthashManager {
EthashManager {
cache: Mutex::new(LightCache {
recent_epoch: None,
recent: None,
prev_epoch: None,
prev: None,
}),
}
}
/// Calculate the light client data
/// `block_number` - Block number to check
/// `light` - The light client handler
/// `header_hash` - The header hash to pack into the mix
/// `nonce` - The nonce to pack into the mix
pub fn compute_light(&self, block_number: u64, header_hash: &H256, nonce: u64) -> ProofOfWork {
let epoch = block_number / ETHASH_EPOCH_LENGTH;
let light = {
let mut lights = self.cache.lock().unwrap();
let light = match lights.recent_epoch.clone() {
Some(ref e) if *e == epoch => lights.recent.clone(),
_ => match lights.prev_epoch.clone() {
Some(e) if e == epoch => {
// swap
let t = lights.prev_epoch;
lights.prev_epoch = lights.recent_epoch;
lights.recent_epoch = t;
let t = lights.prev.clone();
lights.prev = lights.recent.clone();
lights.recent = t;
lights.recent.clone()
}
_ => None,
}
};
match light {
None => {
let light = match Light::from_file(block_number) {
Ok(light) => Arc::new(light),
Err(e) => {
debug!("Light cache file not found for {}:{}", block_number, e);
let light = Light::new(block_number);
if let Err(e) = light.to_file() {
warn!("Light cache file write error: {}", e);
}
Arc::new(light)
}
};
lights.prev_epoch = mem::replace(&mut lights.recent_epoch, Some(epoch));
lights.prev = mem::replace(&mut lights.recent, Some(light.clone()));
light
}
Some(light) => light
}
};
light.compute(header_hash, nonce)
}
}
#[test]
fn test_lru() {
let ethash = EthashManager::new();
let hash = [0u8; 32];
ethash.compute_light(1, &hash, 1);
ethash.compute_light(50000, &hash, 1);
assert_eq!(ethash.cache.lock().unwrap().recent_epoch.unwrap(), 1);
assert_eq!(ethash.cache.lock().unwrap().prev_epoch.unwrap(), 0);
ethash.compute_light(1, &hash, 1);
assert_eq!(ethash.cache.lock().unwrap().recent_epoch.unwrap(), 0);
assert_eq!(ethash.cache.lock().unwrap().prev_epoch.unwrap(), 1);
ethash.compute_light(70000, &hash, 1);
assert_eq!(ethash.cache.lock().unwrap().recent_epoch.unwrap(), 2);
assert_eq!(ethash.cache.lock().unwrap().prev_epoch.unwrap(), 0);
}