openethereum/ethcore/src/snapshot/watcher.rs
Hawstein ade37be25b separate trie from util and make its dependencies into libs:
* bytes
* hashdb
* memorydb
* nibbleslice
* nibblevec
2017-09-15 11:03:53 +08:00

206 lines
4.9 KiB
Rust

// Copyright 2015-2017 Parity Technologies (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/>.
//! Watcher for snapshot-related chain events.
use parking_lot::Mutex;
use client::{BlockChainClient, Client, ChainNotify};
use ids::BlockId;
use service::ClientIoMessage;
use io::IoChannel;
use bigint::hash::H256;
use bytes::Bytes;
use std::sync::Arc;
// helper trait for transforming hashes to numbers and checking if syncing.
trait Oracle: Send + Sync {
fn to_number(&self, hash: H256) -> Option<u64>;
fn is_major_importing(&self) -> bool;
}
struct StandardOracle<F> where F: 'static + Send + Sync + Fn() -> bool {
client: Arc<Client>,
sync_status: F,
}
impl<F> Oracle for StandardOracle<F>
where F: Send + Sync + Fn() -> bool
{
fn to_number(&self, hash: H256) -> Option<u64> {
self.client.block_header(BlockId::Hash(hash)).map(|h| h.number())
}
fn is_major_importing(&self) -> bool {
(self.sync_status)()
}
}
// helper trait for broadcasting a block to take a snapshot at.
trait Broadcast: Send + Sync {
fn take_at(&self, num: Option<u64>);
}
impl Broadcast for Mutex<IoChannel<ClientIoMessage>> {
fn take_at(&self, num: Option<u64>) {
let num = match num {
Some(n) => n,
None => return,
};
trace!(target: "snapshot_watcher", "broadcast: {}", num);
if let Err(e) = self.lock().send(ClientIoMessage::TakeSnapshot(num)) {
warn!("Snapshot watcher disconnected from IoService: {}", e);
}
}
}
/// A `ChainNotify` implementation which will trigger a snapshot event
/// at certain block numbers.
pub struct Watcher {
oracle: Box<Oracle>,
broadcast: Box<Broadcast>,
period: u64,
history: u64,
}
impl Watcher {
/// Create a new `Watcher` which will trigger a snapshot event
/// once every `period` blocks, but only after that block is
/// `history` blocks old.
pub fn new<F>(client: Arc<Client>, sync_status: F, channel: IoChannel<ClientIoMessage>, period: u64, history: u64) -> Self
where F: 'static + Send + Sync + Fn() -> bool
{
Watcher {
oracle: Box::new(StandardOracle {
client: client,
sync_status: sync_status,
}),
broadcast: Box::new(Mutex::new(channel)),
period: period,
history: history,
}
}
}
impl ChainNotify for Watcher {
fn new_blocks(
&self,
imported: Vec<H256>,
_: Vec<H256>,
_: Vec<H256>,
_: Vec<H256>,
_: Vec<H256>,
_: Vec<Bytes>,
_duration: u64)
{
if self.oracle.is_major_importing() { return }
trace!(target: "snapshot_watcher", "{} imported", imported.len());
let highest = imported.into_iter()
.filter_map(|h| self.oracle.to_number(h))
.filter(|&num| num >= self.period + self.history)
.map(|num| num - self.history)
.filter(|num| num % self.period == 0)
.fold(0, ::std::cmp::max);
match highest {
0 => self.broadcast.take_at(None),
_ => self.broadcast.take_at(Some(highest)),
}
}
}
#[cfg(test)]
mod tests {
use super::{Broadcast, Oracle, Watcher};
use client::ChainNotify;
use bigint::prelude::U256;
use bigint::hash::H256;
use std::collections::HashMap;
struct TestOracle(HashMap<H256, u64>);
impl Oracle for TestOracle {
fn to_number(&self, hash: H256) -> Option<u64> {
self.0.get(&hash).cloned()
}
fn is_major_importing(&self) -> bool { false }
}
struct TestBroadcast(Option<u64>);
impl Broadcast for TestBroadcast {
fn take_at(&self, num: Option<u64>) {
if num != self.0 {
panic!("Watcher broadcast wrong number. Expected {:?}, found {:?}", self.0, num);
}
}
}
// helper harness for tests which expect a notification.
fn harness(numbers: Vec<u64>, period: u64, history: u64, expected: Option<u64>) {
let hashes: Vec<_> = numbers.clone().into_iter().map(|x| H256::from(U256::from(x))).collect();
let map = hashes.clone().into_iter().zip(numbers).collect();
let watcher = Watcher {
oracle: Box::new(TestOracle(map)),
broadcast: Box::new(TestBroadcast(expected)),
period: period,
history: history,
};
watcher.new_blocks(
hashes,
vec![],
vec![],
vec![],
vec![],
vec![],
0,
);
}
// helper
#[test]
fn should_not_fire() {
harness(vec![0], 5, 0, None);
}
#[test]
fn fires_once_for_two() {
harness(vec![14, 15], 10, 5, Some(10));
}
#[test]
fn finds_highest() {
harness(vec![15, 25], 10, 5, Some(20));
}
#[test]
fn doesnt_fire_before_history() {
harness(vec![10, 11], 10, 5, None);
}
}