openethereum/ethcore/src/engines/null_engine.rs
2020-09-22 14:53:52 +02:00

144 lines
4.2 KiB
Rust

// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.
// OpenEthereum 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.
// OpenEthereum 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 OpenEthereum. If not, see <http://www.gnu.org/licenses/>.
use block::ExecutedBlock;
use engines::{
block_reward::{self, RewardKind},
Engine,
};
use ethereum_types::U256;
use machine::Machine;
use types::{
ancestry_action::AncestryAction,
header::{ExtendedHeader, Header},
BlockNumber,
};
/// Params for a null engine.
#[derive(Clone, Default)]
pub struct NullEngineParams {
/// base reward for a block.
pub block_reward: U256,
/// Immediate finalization.
pub immediate_finalization: bool,
}
impl From<::ethjson::spec::NullEngineParams> for NullEngineParams {
fn from(p: ::ethjson::spec::NullEngineParams) -> Self {
NullEngineParams {
block_reward: p.block_reward.map_or_else(Default::default, Into::into),
immediate_finalization: p.immediate_finalization.unwrap_or(false),
}
}
}
/// An engine which does not provide any consensus mechanism and does not seal blocks.
pub struct NullEngine<M> {
params: NullEngineParams,
machine: M,
}
impl<M> NullEngine<M> {
/// Returns new instance of NullEngine with default VM Factory
pub fn new(params: NullEngineParams, machine: M) -> Self {
NullEngine {
params: params,
machine: machine,
}
}
}
impl<M: Default> Default for NullEngine<M> {
fn default() -> Self {
Self::new(Default::default(), Default::default())
}
}
impl<M: Machine> Engine<M> for NullEngine<M> {
fn name(&self) -> &str {
"NullEngine"
}
fn machine(&self) -> &M {
&self.machine
}
fn on_close_block(&self, block: &mut ExecutedBlock) -> Result<(), M::Error> {
use std::ops::Shr;
let author = *block.header.author();
let number = block.header.number();
let reward = self.params.block_reward;
if reward == U256::zero() {
return Ok(());
}
let n_uncles = block.uncles.len();
let mut rewards = Vec::new();
// Bestow block reward
let result_block_reward = reward + reward.shr(5) * U256::from(n_uncles);
rewards.push((author, RewardKind::Author, result_block_reward));
// bestow uncle rewards.
for u in &block.uncles {
let uncle_author = u.author();
let result_uncle_reward = (reward * U256::from(8 + u.number() - number)).shr(3);
rewards.push((
*uncle_author,
RewardKind::uncle(number, u.number()),
result_uncle_reward,
));
}
block_reward::apply_block_rewards(&rewards, block, &self.machine)
}
fn maximum_uncle_count(&self, _block: BlockNumber) -> usize {
2
}
fn verify_local_seal(&self, _header: &Header) -> Result<(), M::Error> {
Ok(())
}
fn snapshot_components(&self) -> Option<Box<dyn crate::snapshot::SnapshotComponents>> {
Some(Box::new(::snapshot::PowSnapshot::new(10000, 10000)))
}
fn fork_choice(&self, new: &ExtendedHeader, current: &ExtendedHeader) -> super::ForkChoice {
super::total_difficulty_fork_choice(new, current)
}
fn ancestry_actions(
&self,
_header: &Header,
ancestry: &mut dyn Iterator<Item = ExtendedHeader>,
) -> Vec<AncestryAction> {
if self.params.immediate_finalization {
// always mark parent finalized
ancestry
.take(1)
.map(|e| AncestryAction::MarkFinalized(e.header.hash()))
.collect()
} else {
Vec::new()
}
}
}