// 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 .
//! Snapshot network service implementation.
use std::collections::HashSet;
use std::io::ErrorKind;
use std::fs;
use std::path::{Path, PathBuf};
use std::sync::Arc;
use std::sync::atomic::{AtomicUsize, Ordering};
use super::{ManifestData, StateRebuilder, BlockRebuilder};
use super::io::{SnapshotReader, LooseReader, SnapshotWriter, LooseWriter};
use blockchain::BlockChain;
use client::Client;
use engines::Engine;
use error::Error;
use ids::BlockID;
use service::ClientIoMessage;
use spec::Spec;
use io::IoChannel;
use util::{Bytes, H256, Mutex, RwLock, UtilError};
use util::journaldb::Algorithm;
use util::kvdb::{Database, DatabaseConfig};
use util::snappy;
/// Helper for removing directories in case of error.
struct Guard(bool, PathBuf);
impl Guard {
fn new(path: PathBuf) -> Self { Guard(true, path) }
fn disarm(mut self) { self.0 = false }
}
impl Drop for Guard {
fn drop(&mut self) {
if self.0 {
let _ = fs::remove_dir_all(&self.1);
}
}
}
/// Statuses for restorations.
#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub enum RestorationStatus {
/// No restoration.
Inactive,
/// Ongoing restoration.
Ongoing,
/// Failed restoration.
Failed,
}
/// The interface for a snapshot network service.
/// This handles:
/// - restoration of snapshots to temporary databases.
/// - responding to queries for snapshot manifests and chunks
pub trait SnapshotService {
/// Query the most recent manifest data.
fn manifest(&self) -> Option;
/// Get raw chunk for a given hash.
fn chunk(&self, hash: H256) -> Option;
/// Ask the snapshot service for the restoration status.
fn status(&self) -> RestorationStatus;
/// Ask the snapshot service for the number of chunks completed.
/// Return a tuple of (state_chunks, block_chunks).
/// Undefined when not restoring.
fn chunks_done(&self) -> (usize, usize);
/// Begin snapshot restoration.
/// If restoration in-progress, this will reset it.
/// From this point on, any previous snapshot may become unavailable.
fn begin_restore(&self, manifest: ManifestData);
/// Abort an in-progress restoration if there is one.
fn abort_restore(&self);
/// Feed a raw state chunk to the service to be processed asynchronously.
/// no-op if not currently restoring.
fn restore_state_chunk(&self, hash: H256, chunk: Bytes);
/// Feed a raw block chunk to the service to be processed asynchronously.
/// no-op if currently restoring.
fn restore_block_chunk(&self, hash: H256, chunk: Bytes);
}
/// State restoration manager.
struct Restoration {
manifest: ManifestData,
state_chunks_left: HashSet,
block_chunks_left: HashSet,
state: StateRebuilder,
blocks: BlockRebuilder,
writer: LooseWriter,
snappy_buffer: Bytes,
final_state_root: H256,
guard: Guard,
}
struct RestorationParams<'a> {
manifest: ManifestData, // manifest to base restoration on.
pruning: Algorithm, // pruning algorithm for the database.
db_path: PathBuf, // database path
writer: LooseWriter, // writer for recovered snapshot.
genesis: &'a [u8], // genesis block of the chain.
guard: Guard, // guard for the restoration directory.
}
impl Restoration {
// make a new restoration using the given parameters.
fn new(params: RestorationParams) -> Result {
let manifest = params.manifest;
let state_chunks = manifest.state_hashes.iter().cloned().collect();
let block_chunks = manifest.block_hashes.iter().cloned().collect();
let cfg = DatabaseConfig::with_columns(::db::NUM_COLUMNS);
let raw_db = Arc::new(try!(Database::open(&cfg, &*params.db_path.to_string_lossy())
.map_err(UtilError::SimpleString)));
let chain = BlockChain::new(Default::default(), params.genesis, raw_db.clone());
let blocks = try!(BlockRebuilder::new(chain, manifest.block_number));
let root = manifest.state_root.clone();
Ok(Restoration {
manifest: manifest,
state_chunks_left: state_chunks,
block_chunks_left: block_chunks,
state: StateRebuilder::new(raw_db, params.pruning),
blocks: blocks,
writer: params.writer,
snappy_buffer: Vec::new(),
final_state_root: root,
guard: params.guard,
})
}
// feeds a state chunk
fn feed_state(&mut self, hash: H256, chunk: &[u8]) -> Result<(), Error> {
if self.state_chunks_left.remove(&hash) {
let len = try!(snappy::decompress_into(chunk, &mut self.snappy_buffer));
try!(self.state.feed(&self.snappy_buffer[..len]));
try!(self.writer.write_state_chunk(hash, chunk));
}
Ok(())
}
// feeds a block chunk
fn feed_blocks(&mut self, hash: H256, chunk: &[u8], engine: &Engine) -> Result<(), Error> {
if self.block_chunks_left.remove(&hash) {
let len = try!(snappy::decompress_into(chunk, &mut self.snappy_buffer));
try!(self.blocks.feed(&self.snappy_buffer[..len], engine));
try!(self.writer.write_block_chunk(hash, chunk));
}
Ok(())
}
// finish up restoration.
fn finalize(self) -> Result<(), Error> {
use util::trie::TrieError;
if !self.is_done() { return Ok(()) }
// verify final state root.
let root = self.state.state_root();
if root != self.final_state_root {
warn!("Final restored state has wrong state root: expected {:?}, got {:?}", root, self.final_state_root);
return Err(TrieError::InvalidStateRoot(root).into());
}
// check for missing code.
try!(self.state.check_missing());
// connect out-of-order chunks.
self.blocks.glue_chunks();
try!(self.writer.finish(self.manifest));
self.guard.disarm();
Ok(())
}
// is everything done?
fn is_done(&self) -> bool {
self.block_chunks_left.is_empty() && self.state_chunks_left.is_empty()
}
}
/// Type alias for client io channel.
pub type Channel = IoChannel;
/// Service implementation.
///
/// This will replace the client's state DB as soon as the last state chunk
/// is fed, and will replace the client's blocks DB when the last block chunk
/// is fed.
pub struct Service {
restoration: Mutex