128 lines
3.7 KiB
Rust
128 lines
3.7 KiB
Rust
// Copyright 2015-2017 Parity Technologies (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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//! Ethash implementation
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//! See https://github.com/ethereum/wiki/wiki/Ethash
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extern crate primal;
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extern crate sha3;
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extern crate parking_lot;
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#[macro_use]
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extern crate log;
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mod compute;
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use std::mem;
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use compute::Light;
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pub use compute::{ETHASH_EPOCH_LENGTH, H256, ProofOfWork, SeedHashCompute, quick_get_difficulty, slow_get_seedhash};
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use std::sync::Arc;
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use parking_lot::Mutex;
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struct LightCache {
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recent_epoch: Option<u64>,
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recent: Option<Arc<Light>>,
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prev_epoch: Option<u64>,
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prev: Option<Arc<Light>>,
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}
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/// Light/Full cache manager.
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pub struct EthashManager {
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cache: Mutex<LightCache>,
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}
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impl EthashManager {
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/// Create a new new instance of ethash manager
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pub fn new() -> EthashManager {
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EthashManager {
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cache: Mutex::new(LightCache {
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recent_epoch: None,
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recent: None,
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prev_epoch: None,
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prev: None,
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}),
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}
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}
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/// Calculate the light client data
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/// `block_number` - Block number to check
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/// `light` - The light client handler
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/// `header_hash` - The header hash to pack into the mix
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/// `nonce` - The nonce to pack into the mix
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pub fn compute_light(&self, block_number: u64, header_hash: &H256, nonce: u64) -> ProofOfWork {
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let epoch = block_number / ETHASH_EPOCH_LENGTH;
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let light = {
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let mut lights = self.cache.lock();
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let light = match lights.recent_epoch.clone() {
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Some(ref e) if *e == epoch => lights.recent.clone(),
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_ => match lights.prev_epoch.clone() {
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Some(e) if e == epoch => {
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// don't swap if recent is newer.
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if lights.recent_epoch > lights.prev_epoch {
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None
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} else {
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// swap
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let t = lights.prev_epoch;
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lights.prev_epoch = lights.recent_epoch;
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lights.recent_epoch = t;
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let t = lights.prev.clone();
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lights.prev = lights.recent.clone();
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lights.recent = t;
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lights.recent.clone()
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}
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}
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_ => None,
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},
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};
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match light {
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None => {
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let light = match Light::from_file(block_number) {
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Ok(light) => Arc::new(light),
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Err(e) => {
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debug!("Light cache file not found for {}:{}", block_number, e);
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let light = Light::new(block_number);
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if let Err(e) = light.to_file() {
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warn!("Light cache file write error: {}", e);
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}
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Arc::new(light)
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}
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};
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lights.prev_epoch = mem::replace(&mut lights.recent_epoch, Some(epoch));
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lights.prev = mem::replace(&mut lights.recent, Some(light.clone()));
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light
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}
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Some(light) => light,
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}
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};
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light.compute(header_hash, nonce)
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}
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}
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#[test]
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fn test_lru() {
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let ethash = EthashManager::new();
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let hash = [0u8; 32];
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ethash.compute_light(1, &hash, 1);
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ethash.compute_light(50000, &hash, 1);
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assert_eq!(ethash.cache.lock().recent_epoch.unwrap(), 1);
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assert_eq!(ethash.cache.lock().prev_epoch.unwrap(), 0);
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ethash.compute_light(1, &hash, 1);
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assert_eq!(ethash.cache.lock().recent_epoch.unwrap(), 0);
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assert_eq!(ethash.cache.lock().prev_epoch.unwrap(), 1);
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ethash.compute_light(70000, &hash, 1);
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assert_eq!(ethash.cache.lock().recent_epoch.unwrap(), 2);
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assert_eq!(ethash.cache.lock().prev_epoch.unwrap(), 0);
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}
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