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use std::sync::Arc;
use parking_lot::RwLock;
use db;
use primitives::hash::H256;
/// Thread-safe reference to `Chain`
pub type ChainRef = Arc<RwLock<Chain>>;
/// Index of 'verifying' queue
const VERIFYING_QUEUE: usize = 0;
/// Index of 'requested' queue
const REQUESTED_QUEUE: usize = 1;
/// Index of 'scheduled' queue
const SCHEDULED_QUEUE: usize = 2;
/// Number of hash queues
const NUMBER_OF_QUEUES: usize = 3;
/// Block synchronization state
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub enum BlockState {
/// Block is unknown
Unknown,
/// Scheduled for requesting
Scheduled,
/// Requested from peers
Requested,
/// Currently verifying
Verifying,
/// In storage
Stored,
}
/// Synchronization chain information
#[derive(Debug)]
pub struct Information {
/// Number of blocks currently scheduled for requesting
/// Number of blocks currently requested from peers
/// Number of blocks currently verifying
/// Number of blocks in the storage
/// Result of intersecting chain && inventory
#[derive(Debug, PartialEq)]
pub enum InventoryIntersection {
/// 3.2: No intersection with in-memory queue && no intersection with db
NoKnownBlocks(usize),
/// 2.3: Inventory has no new blocks && some of blocks in inventory are in in-memory queue
InMemoryNoNewBlocks,
/// 2.4.2: Inventory has new blocks && these blocks are right after chain' best block
InMemoryMainNewBlocks(usize),
/// 2.4.3: Inventory has new blocks && these blocks are forked from our chain' best block
InMemoryForkNewBlocks(usize),
/// 3.3: No intersection with in-memory queue && has intersection with db && all blocks are already stored in db
DbAllBlocksKnown,
/// 3.4: No intersection with in-memory queue && has intersection with db && some blocks are not yet stored in db
DbForkNewBlocks(usize),
}
/// Blockchain from synchroniation point of view, consisting of:
/// 1) all blocks from the `storage` [oldest blocks]
/// 2) all blocks currently verifying by `verification_queue`
/// 3) all blocks currently requested from peers
/// 4) all blocks currently scheduled for requesting [newest blocks]
pub struct Chain {
/// Genesis block hash (stored for optimizations)
genesis_block_hash: H256,
/// Best storage block (stored for optimizations)
best_storage_block: db::BestBlock,
/// Local blocks storage
storage: Arc<db::Store>,
/// In-memory queue of blocks hashes
hash_chain: HashQueueChain,
/// Transactions memory pool
memory_pool: MemoryPool,
}
impl BlockState {
pub fn from_queue_index(queue_index: usize) -> BlockState {
match queue_index {
SCHEDULED_QUEUE => BlockState::Scheduled,
REQUESTED_QUEUE => BlockState::Requested,
VERIFYING_QUEUE => BlockState::Verifying,
_ => panic!("Unsupported queue_index: {}", queue_index),
}
}
pub fn to_queue_index(&self) -> usize {
match self {
&BlockState::Scheduled => SCHEDULED_QUEUE,
&BlockState::Requested => REQUESTED_QUEUE,
&BlockState::Verifying => VERIFYING_QUEUE,
_ => panic!("Unsupported queue: {:?}", self),
}
}
}
impl Chain {
/// Create new `Chain` with given storage
pub fn new(storage: Arc<db::Store>) -> Self {
// we only work with storages with genesis block
let genesis_block_hash = storage.block_hash(0)
.expect("storage with genesis block is required");
let best_storage_block = storage.best_block()
.expect("non-empty storage is required");
Chain {
genesis_block_hash: genesis_block_hash,
best_storage_block: best_storage_block,
storage: storage,
hash_chain: HashQueueChain::with_number_of_queues(NUMBER_OF_QUEUES),
}
}
/// Get information on current blockchain state
pub fn information(&self) -> Information {
Information {
scheduled: self.hash_chain.len_of(SCHEDULED_QUEUE),
requested: self.hash_chain.len_of(REQUESTED_QUEUE),
verifying: self.hash_chain.len_of(VERIFYING_QUEUE),
stored: self.best_storage_block.number + 1,
/// Get storage
pub fn storage(&self) -> Arc<db::Store> {
self.storage.clone()
}
/// Get memory pool reference
pub fn memory_pool<'a>(&'a self) -> &'a MemoryPool {
&self.memory_pool
}
/// Get mutable memory pool reference
#[cfg(test)]
pub fn memory_pool_mut<'a>(&'a mut self) -> &'a mut MemoryPool {
&mut self.memory_pool
}
/// Get number of blocks in given state
pub fn length_of_state(&self, state: BlockState) -> u32 {
match state {
BlockState::Stored => self.best_storage_block.number + 1,
_ => self.hash_chain.len_of(state.to_queue_index()),
}
}
/// Get best block
pub fn best_block(&self) -> db::BestBlock {
match self.hash_chain.back() {
Some(hash) => db::BestBlock {
number: self.best_storage_block.number + self.hash_chain.len(),
hash: hash.clone(),
},
None => self.best_storage_block.clone(),
}
}
/// Get block state
pub fn block_state(&self, hash: &H256) -> BlockState {
match self.hash_chain.contains_in(hash) {
Some(queue_index) => BlockState::from_queue_index(queue_index),
None => if self.storage.contains_block(db::BlockRef::Hash(hash.clone())) {
BlockState::Stored
} else {
BlockState::Unknown
},
}
}
/// Prepare block locator hashes, as described in protocol documentation:
/// https://en.bitcoin.it/wiki/Protocol_documentation#getblocks
/// When there are forked blocks in the queue, this method can result in
/// mixed block locator hashes ([0 - from fork1, 1 - from fork2, 2 - from fork1]).
/// Peer will respond with blocks of fork1 || fork2 => we could end up in some side fork
/// To resolve this, after switching to saturated state, we will also ask all peers for inventory.
pub fn block_locator_hashes(&self) -> Vec<H256> {
let mut block_locator_hashes: Vec<H256> = Vec::new();
// calculate for hash_queue
let (local_index, step) = self.block_locator_hashes_for_queue(&mut block_locator_hashes);
// calculate for storage
let storage_index = if self.best_storage_block.number < local_index { 0 } else { self.best_storage_block.number - local_index };
self.block_locator_hashes_for_storage(storage_index, step, &mut block_locator_hashes);
block_locator_hashes
}
/// Schedule blocks for requesting
pub fn schedule_blocks_hashes(&mut self, hashes: Vec<H256>) {
self.hash_chain.push_back_n_at(SCHEDULED_QUEUE, hashes)
}
/// Moves n blocks from scheduled queue to requested queue
pub fn request_blocks_hashes(&mut self, n: u32) -> Vec<H256> {
let scheduled = self.hash_chain.pop_front_n_at(SCHEDULED_QUEUE, n);
self.hash_chain.push_back_n_at(REQUESTED_QUEUE, scheduled.clone());
scheduled
}
/// Add block to verifying queue
pub fn verify_block_hash(&mut self, hash: H256) {
self.hash_chain.push_back_at(VERIFYING_QUEUE, hash);
}
/// Moves n blocks from requested queue to verifying queue
#[cfg(test)]
pub fn verify_blocks_hashes(&mut self, n: u32) -> Vec<H256> {
let requested = self.hash_chain.pop_front_n_at(REQUESTED_QUEUE, n);
self.hash_chain.push_back_n_at(VERIFYING_QUEUE, requested.clone());
requested
}
/// Insert new best block to storage
pub fn insert_best_block(&mut self, block: Block) -> Result<(), db::Error> {
// insert to storage
try!(self.storage.insert_block(&block));
self.best_storage_block = self.storage.best_block().expect("Inserted block above");
Ok(())
}
/// Remove block
pub fn remove_block(&mut self, hash: &H256) {
if self.hash_chain.remove_at(SCHEDULED_QUEUE, hash) == HashPosition::Missing
&& self.hash_chain.remove_at(REQUESTED_QUEUE, hash) == HashPosition::Missing {
self.hash_chain.remove_at(VERIFYING_QUEUE, hash);
}
}
/// Remove block by hash if it is currently in given state
pub fn remove_block_with_state(&mut self, hash: &H256, state: BlockState) -> HashPosition {
self.hash_chain.remove_at(state.to_queue_index(), hash)
}
/// Remove all blocks with given state
pub fn remove_blocks_with_state(&mut self, state: BlockState) {
self.hash_chain.remove_all_at(state.to_queue_index());
}
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/// Intersect chain with inventory
pub fn intersect_with_inventory(&self, inventory: &Vec<H256>) -> InventoryIntersection {
let inventory_len = inventory.len();
assert!(inventory_len != 0);
// giving that blocks in inventory are ordered
match self.block_state(&inventory[0]) {
// if first block of inventory is unknown => all other blocks are also unknown
BlockState::Unknown => {
InventoryIntersection::NoKnownBlocks(0)
},
// else if first block is known
first_block_state @ _ => match self.block_state(&inventory[inventory_len - 1]) {
// if last block is known to be in db => all inventory blocks are also in db
BlockState::Stored => {
InventoryIntersection::DbAllBlocksKnown
},
// if first block is known && last block is unknown => intersection with queue or with db
BlockState::Unknown => {
// find last known block
let mut previous_state = first_block_state;
for index in 1..inventory_len {
let state = self.block_state(&inventory[index]);
if state == BlockState::Unknown {
// previous block is stored => fork from stored block
if previous_state == BlockState::Stored {
return InventoryIntersection::DbForkNewBlocks(index);
}
// previous block is best block => no fork
else if &self.best_block().hash == &inventory[index - 1] {
return InventoryIntersection::InMemoryMainNewBlocks(index);
}
// previous block is not a best block => fork
else {
return InventoryIntersection::InMemoryForkNewBlocks(index);
}
}
previous_state = state;
}
// unreachable because last block is unknown && in above loop we search for unknown blocks
unreachable!();
},
// if first block is known && last block is also known && is in queue => queue intersection with no new block
_ => {
InventoryIntersection::InMemoryNoNewBlocks
}
}
}
}
/// Calculate block locator hashes for hash queue
fn block_locator_hashes_for_queue(&self, hashes: &mut Vec<H256>) -> (u32, u32) {
let queue_len = self.hash_chain.len();
if queue_len == 0 {
let block_hash = self.hash_chain[index].clone();
if hashes.len() >= 10 {
step <<= 1;
}
if index < step {
return (step - index - 1, step);
}
}
/// Calculate block locator hashes for storage
fn block_locator_hashes_for_storage(&self, mut index: u32, mut step: u32, hashes: &mut Vec<H256>) {
let block_hash = self.storage.block_hash(index)
.expect("private function; index calculated in `block_locator_hashes`; qed");
hashes.push(block_hash);
if hashes.len() >= 10 {
step <<= 1;
}
if index < step {
// always include genesis hash
if index != 0 {
hashes.push(self.genesis_block_hash.clone())
}
break;
}
index -= step;
}
}
}
impl fmt::Debug for Chain {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
try!(writeln!(f, "chain: ["));
let mut num = self.best_storage_block.number;
try!(writeln!(f, "\tworse(stored): {} {:?}", 0, self.storage.block_hash(0)));
try!(writeln!(f, "\tbest(stored): {} {:?}", num, self.storage.block_hash(num)));
let queues = vec![
("verifying", VERIFYING_QUEUE),
("requested", REQUESTED_QUEUE),
("scheduled", SCHEDULED_QUEUE),
];
for (state, queue) in queues {
let queue_len = self.hash_chain.len_of(queue);
if queue_len != 0 {
try!(writeln!(f, "\tworse({}): {} {:?}", state, num + 1, self.hash_chain.front_at(queue)));
if let Some(pre_best) = self.hash_chain.pre_back_at(queue) {
try!(writeln!(f, "\tpre-best({}): {} {:?}", state, num - 1, pre_best));
}
try!(writeln!(f, "\tbest({}): {} {:?}", state, num, self.hash_chain.back_at(queue)));
}
}
use super::{Chain, BlockState, InventoryIntersection};
use db::{self, Store, BestBlock};
#[test]
fn chain_empty() {
let db = Arc::new(db::TestStorage::with_genesis_block());
let db_best_block = BestBlock { number: 0, hash: db.best_block().expect("storage with genesis block is required").hash };
let chain = Chain::new(db.clone());
assert_eq!(chain.information().scheduled, 0);
assert_eq!(chain.information().requested, 0);
assert_eq!(chain.information().verifying, 0);
assert_eq!(chain.information().stored, 1);
assert_eq!(chain.length_of_state(BlockState::Scheduled), 0);
assert_eq!(chain.length_of_state(BlockState::Requested), 0);
assert_eq!(chain.length_of_state(BlockState::Verifying), 0);
assert_eq!(chain.length_of_state(BlockState::Stored), 1);
assert_eq!(&chain.best_block(), &db_best_block);
assert_eq!(chain.block_state(&db_best_block.hash), BlockState::Stored);
assert_eq!(chain.block_state(&H256::from(0)), BlockState::Unknown);
}
#[test]
fn chain_block_path() {
let db = Arc::new(db::TestStorage::with_genesis_block());
let mut chain = Chain::new(db.clone());
// add 6 blocks to scheduled queue
chain.schedule_blocks_hashes(vec![
H256::from(0),
H256::from(1),
H256::from(2),
H256::from(3),
H256::from(4),
H256::from(5),
]);
assert!(chain.information().scheduled == 6 && chain.information().requested == 0
&& chain.information().verifying == 0 && chain.information().stored == 1);
// move 2 best blocks (0 && 1) to requested queue
chain.request_blocks_hashes(2);
assert!(chain.information().scheduled == 4 && chain.information().requested == 2
&& chain.information().verifying == 0 && chain.information().stored == 1);
// move 0 best blocks to requested queue
chain.request_blocks_hashes(0);
assert!(chain.information().scheduled == 4 && chain.information().requested == 2
&& chain.information().verifying == 0 && chain.information().stored == 1);
// move 1 best blocks (2) to requested queue
chain.request_blocks_hashes(1);
assert!(chain.information().scheduled == 3 && chain.information().requested == 3
&& chain.information().verifying == 0 && chain.information().stored == 1);
// try to remove block 0 from scheduled queue => missing
assert_eq!(chain.remove_block_with_state(&H256::from(0), BlockState::Scheduled), HashPosition::Missing);
assert!(chain.information().scheduled == 3 && chain.information().requested == 3
&& chain.information().verifying == 0 && chain.information().stored == 1);
// remove blocks 0 & 1 from requested queue
assert_eq!(chain.remove_block_with_state(&H256::from(1), BlockState::Requested), HashPosition::Inside);
assert_eq!(chain.remove_block_with_state(&H256::from(0), BlockState::Requested), HashPosition::Front);
assert!(chain.information().scheduled == 3 && chain.information().requested == 1
&& chain.information().verifying == 0 && chain.information().stored == 1);
// mark 0 & 1 as verifying
chain.verify_block_hash(H256::from(1));
chain.verify_block_hash(H256::from(2));
assert!(chain.information().scheduled == 3 && chain.information().requested == 1
&& chain.information().verifying == 2 && chain.information().stored == 1);
// mark block 0 as verified
assert_eq!(chain.remove_block_with_state(&H256::from(1), BlockState::Verifying), HashPosition::Front);
assert!(chain.information().scheduled == 3 && chain.information().requested == 1
&& chain.information().verifying == 1 && chain.information().stored == 1);
// insert new best block to the chain
chain.insert_best_block(test_data::block_h1()).expect("Db error");
assert!(chain.information().scheduled == 3 && chain.information().requested == 1
&& chain.information().verifying == 1 && chain.information().stored == 2);
assert_eq!(db.best_block().expect("storage with genesis block is required").number, 1);
}
#[test]
fn chain_block_locator_hashes() {
let mut chain = Chain::new(Arc::new(db::TestStorage::with_genesis_block()));
let genesis_hash = chain.best_block().hash;
assert_eq!(chain.block_locator_hashes(), vec![genesis_hash.clone()]);
chain.insert_best_block(block1).expect("Error inserting new block");
assert_eq!(chain.block_locator_hashes(), vec![block1_hash.clone(), genesis_hash.clone()]);
chain.insert_best_block(block2).expect("Error inserting new block");
assert_eq!(chain.block_locator_hashes(), vec![block2_hash.clone(), block1_hash.clone(), genesis_hash.clone()]);
chain.schedule_blocks_hashes(vec![
H256::from(0),
H256::from(1),
H256::from(2),
H256::from(3),
H256::from(4),
H256::from(5),
H256::from(6),
H256::from(7),
H256::from(8),
H256::from(9),
H256::from(10),
]);
chain.request_blocks_hashes(10);
chain.verify_blocks_hashes(10);
assert_eq!(chain.block_locator_hashes(), vec![
H256::from(10),
H256::from(9),
H256::from(8),
H256::from(7),
H256::from(6),
H256::from(5),
H256::from(4),
H256::from(3),
H256::from(2),
H256::from(1),
block2_hash.clone(),
genesis_hash.clone(),
]);
chain.schedule_blocks_hashes(vec![
H256::from(11),
H256::from(12),
H256::from(13),
H256::from(14),
H256::from(15),
H256::from(16),
]);
chain.request_blocks_hashes(10);
assert_eq!(chain.block_locator_hashes(), vec![
H256::from(16),
H256::from(15),
H256::from(14),
H256::from(13),
H256::from(12),
H256::from(11),
H256::from(10),
H256::from(9),
H256::from(8),
H256::from(7),
H256::from(5),
H256::from(1),
genesis_hash.clone(),
]);
chain.schedule_blocks_hashes(vec![
H256::from(20),
H256::from(21),
H256::from(22),
]);
assert_eq!(chain.block_locator_hashes(), vec![
H256::from(22),
H256::from(21),
H256::from(20),
H256::from(16),
H256::from(15),
H256::from(14),
H256::from(13),
H256::from(12),
H256::from(11),
H256::from(10),
H256::from(8),
H256::from(4),
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#[test]
fn chain_intersect_with_inventory() {
let mut chain = Chain::new(Arc::new(db::TestStorage::with_genesis_block()));
// append 2 db blocks
chain.insert_best_block(test_data::block_h1()).expect("Error inserting new block");
chain.insert_best_block(test_data::block_h2()).expect("Error inserting new block");
// append 3 verifying blocks
chain.schedule_blocks_hashes(vec![
H256::from(0),
H256::from(1),
H256::from(2),
]);
chain.request_blocks_hashes(3);
chain.verify_blocks_hashes(3);
// append 3 requested blocks
chain.schedule_blocks_hashes(vec![
H256::from(10),
H256::from(11),
H256::from(12),
]);
chain.request_blocks_hashes(10);
// append 3 scheduled blocks
chain.schedule_blocks_hashes(vec![
H256::from(20),
H256::from(21),
H256::from(22),
]);
assert_eq!(chain.intersect_with_inventory(&vec![
H256::from(30),
H256::from(31),
]), InventoryIntersection::NoKnownBlocks(0));
assert_eq!(chain.intersect_with_inventory(&vec![
H256::from(2),
H256::from(10),
H256::from(11),
H256::from(12),
H256::from(20),
]), InventoryIntersection::InMemoryNoNewBlocks);
assert_eq!(chain.intersect_with_inventory(&vec![
H256::from(21),
H256::from(22),
H256::from(30),
H256::from(31),
]), InventoryIntersection::InMemoryMainNewBlocks(2));
assert_eq!(chain.intersect_with_inventory(&vec![
H256::from(20),
H256::from(21),
H256::from(30),
H256::from(31),
]), InventoryIntersection::InMemoryForkNewBlocks(2));
assert_eq!(chain.intersect_with_inventory(&vec![
test_data::block_h1().hash(),
test_data::block_h2().hash(),
]), InventoryIntersection::DbAllBlocksKnown);
assert_eq!(chain.intersect_with_inventory(&vec![
test_data::block_h2().hash(),
H256::from(30),
H256::from(31),
]), InventoryIntersection::DbForkNewBlocks(1));
}