openethereum/sync/src/blocks.rs

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// 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/>.
use util::*;
use ethcore::header::{ Header as BlockHeader};
known_heap_size!(0, HeaderId, SyncBlock);
/// Block data with optional body.
struct SyncBlock {
header: Bytes,
body: Option<Bytes>,
}
/// Used to identify header by transactions and uncles hashes
#[derive(Eq, PartialEq, Hash)]
struct HeaderId {
transactions_root: H256,
uncles: H256
}
/// A collection of blocks and subchain pointers being downloaded. This keeps track of
/// which headers/bodies need to be downloaded, which are being downloaded and also holds
/// the downloaded blocks.
pub struct BlockCollection {
/// Heads of subchains to download
heads: Vec<H256>,
/// Downloaded blocks.
blocks: HashMap<H256, SyncBlock>,
/// Downloaded blocks by parent.
parents: HashMap<H256, H256>,
/// Used to map body to header.
header_ids: HashMap<HeaderId, H256>,
/// First block in `blocks`.
head: Option<H256>,
/// Set of block header hashes being downloaded
downloading_headers: HashSet<H256>,
/// Set of block bodies being downloaded identified by block hash.
downloading_bodies: HashSet<H256>,
}
impl BlockCollection {
/// Create a new instance.
pub fn new() -> BlockCollection {
BlockCollection {
blocks: HashMap::new(),
header_ids: HashMap::new(),
heads: Vec::new(),
parents: HashMap::new(),
head: None,
downloading_headers: HashSet::new(),
downloading_bodies: HashSet::new(),
}
}
/// Clear everything.
pub fn clear(&mut self) {
self.blocks.clear();
self.parents.clear();
self.header_ids.clear();
self.heads.clear();
self.head = None;
self.downloading_headers.clear();
self.downloading_bodies.clear();
}
/// Reset collection for a new sync round with given subchain block hashes.
pub fn reset_to(&mut self, hashes: Vec<H256>) {
self.clear();
self.heads = hashes;
}
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/// Insert a set of headers into collection and advance subchain head pointers.
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pub fn insert_headers(&mut self, headers: Vec<Bytes>) {
for h in headers.into_iter() {
if let Err(e) = self.insert_header(h) {
trace!(target: "sync", "Ignored invalid header: {:?}", e);
}
}
self.update_heads();
}
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/// Insert a collection of block bodies for previously downloaded headers.
pub fn insert_bodies(&mut self, bodies: Vec<Bytes>) {
for b in bodies.into_iter() {
if let Err(e) = self.insert_body(b) {
trace!(target: "sync", "Ignored invalid body: {:?}", e);
}
}
}
/// Returns a set of block hashes that require a body download. The returned set is marked as being downloaded.
pub fn needed_bodies(&mut self, count: usize, _ignore_downloading: bool) -> Vec<H256> {
if self.head.is_none() {
return Vec::new();
}
let mut needed_bodies: Vec<H256> = Vec::new();
let mut head = self.head;
while head.is_some() && needed_bodies.len() < count {
head = self.parents.get(&head.unwrap()).cloned();
if let Some(head) = head {
match self.blocks.get(&head) {
Some(block) if block.body.is_none() && !self.downloading_bodies.contains(&head) => {
needed_bodies.push(head.clone());
}
_ => (),
}
}
}
self.downloading_bodies.extend(needed_bodies.iter());
needed_bodies
}
/// Returns a set of block hashes that require a header download. The returned set is marked as being downloaded.
pub fn needed_headers(&mut self, count: usize, ignore_downloading: bool) -> Option<(H256, usize)> {
// find subchain to download
let mut download = None;
{
for h in &self.heads {
if ignore_downloading || !self.downloading_headers.contains(&h) {
self.downloading_headers.insert(h.clone());
download = Some(h.clone());
break;
}
}
}
download.map(|h| (h, count))
}
/// Unmark a header as being downloaded.
pub fn clear_header_download(&mut self, hash: &H256) {
self.downloading_headers.remove(hash);
}
/// Unmark a block body as being downloaded.
pub fn clear_body_download(&mut self, hash: &H256) {
self.downloading_bodies.remove(hash);
}
/// Get a valid chain of blocks ordered in descending order and ready for importing into blockchain.
pub fn drain(&mut self) -> Vec<Bytes> {
if self.blocks.is_empty() || self.head.is_none() {
return Vec::new();
}
let mut drained = Vec::new();
let mut hashes = Vec::new();
{
let mut blocks = Vec::new();
let mut head = self.head;
while head.is_some() {
head = self.parents.get(&head.unwrap()).cloned();
if let Some(head) = head {
match self.blocks.get(&head) {
Some(block) if block.body.is_some() => {
blocks.push(block);
hashes.push(head);
self.head = Some(head);
}
_ => break,
}
}
}
for block in blocks.drain(..) {
let mut block_rlp = RlpStream::new_list(3);
block_rlp.append_raw(&block.header, 1);
let body = Rlp::new(&block.body.as_ref().unwrap()); // incomplete blocks are filtered out in the loop above
block_rlp.append_raw(body.at(0).as_raw(), 1);
block_rlp.append_raw(body.at(1).as_raw(), 1);
drained.push(block_rlp.out());
}
}
for h in hashes {
self.blocks.remove(&h);
}
trace!("Drained {} blocks, new head :{:?}", drained.len(), self.head);
drained
}
/// Check if the collection is empty. We consider the syncing round complete once
/// there is no block data left and only a single or none head pointer remains.
pub fn is_empty(&self) -> bool {
return self.heads.len() == 0 ||
(self.heads.len() == 1 && self.head.map_or(false, |h| h == self.heads[0]))
}
/// Chech is collection contains a block header.
pub fn contains(&self, hash: &H256) -> bool {
self.blocks.contains_key(hash)
}
/// Return heap size.
pub fn heap_size(&self) -> usize {
//TODO: other collections
self.blocks.heap_size_of_children()
}
/// Check if given block hash is marked as being downloaded.
pub fn is_downloading(&self, hash: &H256) -> bool {
self.downloading_headers.contains(hash) || self.downloading_bodies.contains(hash)
}
fn insert_body(&mut self, b: Bytes) -> Result<(), UtilError> {
let body = UntrustedRlp::new(&b);
let tx = try!(body.at(0));
let tx_root = ordered_trie_root(tx.iter().map(|r| r.as_raw().to_vec()).collect()); //TODO: get rid of vectors here
let uncles = try!(body.at(1)).as_raw().sha3();
let header_id = HeaderId {
transactions_root: tx_root,
uncles: uncles
};
match self.header_ids.get(&header_id).cloned() {
Some(h) => {
self.header_ids.remove(&header_id);
self.downloading_bodies.remove(&h);
match self.blocks.get_mut(&h) {
Some(ref mut block) => {
trace!(target: "sync", "Got body {}", h);
block.body = Some(body.as_raw().to_vec());
},
None => warn!("Got body with no header {}", h)
}
}
None => trace!(target: "sync", "Ignored unknown/stale block body")
};
Ok(())
}
fn insert_header(&mut self, header: Bytes) -> Result<H256, UtilError> {
let info: BlockHeader = try!(UntrustedRlp::new(&header).as_val());
let hash = info.hash();
if self.blocks.contains_key(&hash) {
return Ok(hash);
}
match self.head {
None if hash == self.heads[0] => {
trace!("New head {}", hash);
self.head = Some(info.parent_hash);
},
_ => ()
}
let mut block = SyncBlock {
header: header,
body: None,
};
let header_id = HeaderId {
transactions_root: info.transactions_root,
uncles: info.uncles_hash
};
if header_id.transactions_root == rlp::SHA3_NULL_RLP && header_id.uncles == rlp::SHA3_EMPTY_LIST_RLP {
// empty body, just mark as downloaded
let mut body_stream = RlpStream::new_list(2);
body_stream.append_raw(&rlp::NULL_RLP, 1);
body_stream.append_raw(&rlp::EMPTY_LIST_RLP, 1);
block.body = Some(body_stream.out());
}
else {
self.header_ids.insert(header_id, hash.clone());
}
self.parents.insert(info.parent_hash.clone(), hash.clone());
self.blocks.insert(hash.clone(), block);
Ok(hash)
}
// update subchain headers
fn update_heads(&mut self) {
let mut new_heads = Vec::new();
let old_subchains: HashSet<_> = { self.heads.iter().map(Clone::clone).collect() };
for s in self.heads.drain(..) {
let mut h = s.clone();
loop {
match self.parents.get(&h) {
Some(next) => {
h = next.clone();
if old_subchains.contains(&h) {
trace!("Completed subchain {:?}", s);
break; // reached head of the other subchain, merge by not adding
}
},
_ => {
new_heads.push(h);
break;
}
}
}
}
self.heads = new_heads;
}
}
#[cfg(test)]
mod test {
use super::BlockCollection;
use ethcore::client::{TestBlockChainClient, EachBlockWith, BlockId, BlockChainClient};
use ethcore::views::HeaderView;
use ethcore::header::BlockNumber;
use util::*;
fn is_empty(bc: &BlockCollection) -> bool {
bc.heads.is_empty() &&
bc.blocks.is_empty() &&
bc.parents.is_empty() &&
bc.header_ids.is_empty() &&
bc.head.is_none() &&
bc.downloading_headers.is_empty() &&
bc.downloading_bodies.is_empty()
}
#[test]
fn create_clear() {
let mut bc = BlockCollection::new();
assert!(is_empty(&bc));
let client = TestBlockChainClient::new();
client.add_blocks(100, EachBlockWith::Nothing);
let hashes = (0 .. 100).map(|i| (&client as &BlockChainClient).block_hash(BlockId::Number(i)).unwrap()).collect();
bc.reset_to(hashes);
assert!(!is_empty(&bc));
bc.clear();
assert!(is_empty(&bc));
}
#[test]
fn insert_headers() {
let mut bc = BlockCollection::new();
assert!(is_empty(&bc));
let client = TestBlockChainClient::new();
let nblocks = 200;
client.add_blocks(nblocks, EachBlockWith::Nothing);
let blocks: Vec<_> = (0 .. nblocks).map(|i| (&client as &BlockChainClient).block(BlockId::Number(i as BlockNumber)).unwrap()).collect();
let headers: Vec<_> = blocks.iter().map(|b| Rlp::new(b).at(0).as_raw().to_vec()).collect();
let hashes: Vec<_> = headers.iter().map(|h| HeaderView::new(h).sha3()).collect();
let heads: Vec<_> = hashes.iter().enumerate().filter_map(|(i, h)| if i % 20 == 0 { Some(h.clone()) } else { None }).collect();
bc.reset_to(heads);
assert!(!bc.is_empty());
assert_eq!(hashes[0], bc.heads[0]);
assert!(bc.needed_bodies(1, false).is_empty());
assert!(!bc.contains(&hashes[0]));
assert!(!bc.is_downloading(&hashes[0]));
let (h, n) = bc.needed_headers(6, false).unwrap();
assert!(bc.is_downloading(&hashes[0]));
assert_eq!(hashes[0], h);
assert_eq!(n, 6);
assert_eq!(bc.downloading_headers.len(), 1);
assert!(bc.drain().is_empty());
bc.insert_headers(headers[0..6].to_vec());
assert_eq!(hashes[5], bc.heads[0]);
for h in &hashes[0..6] {
bc.clear_header_download(h)
}
assert_eq!(bc.downloading_headers.len(), 0);
assert!(!bc.is_downloading(&hashes[0]));
assert!(bc.contains(&hashes[0]));
assert_eq!(&bc.drain()[..], &blocks[0..6]);
assert!(!bc.contains(&hashes[0]));
assert_eq!(hashes[5], bc.head.unwrap());
let (h, _) = bc.needed_headers(6, false).unwrap();
assert_eq!(hashes[5], h);
let (h, _) = bc.needed_headers(6, false).unwrap();
assert_eq!(hashes[20], h);
bc.insert_headers(headers[10..16].to_vec());
assert!(bc.drain().is_empty());
bc.insert_headers(headers[5..10].to_vec());
assert_eq!(&bc.drain()[..], &blocks[6..16]);
assert_eq!(hashes[15], bc.heads[0]);
bc.insert_headers(headers[16..].to_vec());
bc.drain();
assert!(bc.is_empty());
}
#[test]
fn insert_headers_with_gap() {
let mut bc = BlockCollection::new();
assert!(is_empty(&bc));
let client = TestBlockChainClient::new();
let nblocks = 200;
client.add_blocks(nblocks, EachBlockWith::Nothing);
let blocks: Vec<_> = (0 .. nblocks).map(|i| (&client as &BlockChainClient).block(BlockId::Number(i as BlockNumber)).unwrap()).collect();
let headers: Vec<_> = blocks.iter().map(|b| Rlp::new(b).at(0).as_raw().to_vec()).collect();
let hashes: Vec<_> = headers.iter().map(|h| HeaderView::new(h).sha3()).collect();
let heads: Vec<_> = hashes.iter().enumerate().filter_map(|(i, h)| if i % 20 == 0 { Some(h.clone()) } else { None }).collect();
bc.reset_to(heads);
bc.insert_headers(headers[2..22].to_vec());
assert_eq!(hashes[0], bc.heads[0]);
assert_eq!(hashes[21], bc.heads[1]);
assert!(bc.head.is_none());
bc.insert_headers(headers[0..2].to_vec());
assert!(bc.head.is_some());
assert_eq!(hashes[21], bc.heads[0]);
}
}