diff --git a/src/blockchain.rs b/src/blockchain.rs index 70577fac9..7e3acb05a 100644 --- a/src/blockchain.rs +++ b/src/blockchain.rs @@ -17,6 +17,15 @@ use extras::*; use transaction::*; use views::*; +/// blocks - a vector of hashes of all blocks, ordered from `from` block to `to` block. +/// ancestor - best common ancestor of these blocks +/// index - an index where best common ancestor would be +pub struct TreeRoute { + pub blocks: Vec, + pub ancestor: H256, + pub index: usize +} + #[derive(Debug)] pub struct CacheSize { pub blocks: usize, @@ -27,7 +36,9 @@ pub struct CacheSize { } pub struct BlockChain { - last_block_number: Cell, + best_block_hash: Cell, + best_block_number: Cell, + best_block_total_difficulty: Cell, // block cache blocks: RefCell>, @@ -57,31 +68,34 @@ impl BlockChain { /// use util::uint::*; /// /// fn main() { + /// let genesis = Genesis::new_frontier(); + /// /// let mut dir = env::temp_dir(); /// dir.push(H32::random().hex()); /// - /// let genesis = Genesis::new_frontier(); - /// let bc = BlockChain::new(genesis, &dir); + /// let bc = BlockChain::new(&genesis, &dir); + /// /// let genesis_hash = "d4e56740f876aef8c010b86a40d5f56745a118d0906a34e69aec8c0db1cb8fa3"; /// assert_eq!(bc.genesis_hash(), H256::from_str(genesis_hash).unwrap()); /// assert!(bc.is_known(&bc.genesis_hash())); /// assert_eq!(bc.genesis_hash(), bc.block_hash(&U256::from(0u8)).unwrap()); /// } /// ``` - pub fn new(genesis: Genesis, path: &Path) -> BlockChain { - let (genesis_block, _genesis_state) = genesis.drain(); - - // open dbs + pub fn new(genesis: &Genesis, path: &Path) -> BlockChain { + // open extras db let mut extras_path = path.to_path_buf(); extras_path.push("extras"); let extras_db = DB::open_default(extras_path.to_str().unwrap()).unwrap(); + // open blocks db let mut blocks_path = path.to_path_buf(); blocks_path.push("blocks"); let blocks_db = DB::open_default(blocks_path.to_str().unwrap()).unwrap(); let bc = BlockChain { - last_block_number: Cell::new(U256::from(0u8)), + best_block_hash: Cell::new(H256::new()), + best_block_number: Cell::new(U256::from(0u8)), + best_block_total_difficulty: Cell::new(U256::from(0u8)), blocks: RefCell::new(HashMap::new()), block_details: RefCell::new(HashMap::new()), block_hashes: RefCell::new(HashMap::new()), @@ -92,14 +106,119 @@ impl BlockChain { blocks_db: blocks_db }; - bc.insert_block(&genesis_block); + // load best block + let best_block_hash = match bc.extras_db.get(b"best").unwrap() { + Some(best) => H256::from_slice(&best), + None => { + // best block does not exist + // we need to insert genesis into the cache + let bytes = genesis.block(); + let block = BlockView::new(bytes); + let header = block.header_view(); + let hash = block.sha3(); + + let details = BlockDetails { + number: header.number(), + total_difficulty: header.difficulty(), + parent: header.parent_hash(), + children: vec![] + }; + + bc.blocks_db.put(&hash, bytes).unwrap(); + + let batch = WriteBatch::new(); + batch.put_extras(&hash, &details); + batch.put_extras(&header.number(), &hash); + batch.put(b"best", &hash).unwrap(); + bc.extras_db.write(batch).unwrap(); + + hash + } + }; + + bc.best_block_hash.set(best_block_hash); + bc.best_block_number.set(bc.block_number(&best_block_hash).unwrap()); + bc.best_block_total_difficulty.set(bc.block_details(&best_block_hash).unwrap().total_difficulty); + bc } + /// Returns a tree route between `from` and `to`, which is a tuple of: + /// - a vector of hashes of all blocks, ordered from `from` to `to`. + /// - common ancestor of these blocks. + /// - an index where best common ancestor would be + /// + /// 1.) live blocks only: + /// + /// bc: A1 -> A2 -> A3 -> A4 -> A5 + /// from: A5, to: A4 + /// route: { blocks: [A5, A4], ancestor: A3, index: 2 } + /// + /// 2.) bad blocks only: + /// + /// bc: A1 -> A2 -> A3 -> A4 -> A5 + /// -> B2 -> B3 -> B4 + /// from: B4, to: B3 + /// route: { blocks: [B4, B3], ancestor: B2, index: 2 } + /// + /// 3.) fork: + /// + /// bc: A1 -> A2 -> A3 -> A4 + /// -> B3 -> B4 + /// from: B4, to: A4 + /// route: { blocks: [B4, B3, A3, A4], ancestor: A2, index: 2 } + pub fn tree_route(&self, from: &H256, to: &H256) -> TreeRoute { + let mut from_branch = vec![]; + let mut to_branch = vec![]; + + let mut from_details = self.block_details(from).expect("from hash is invalid!"); + let mut to_details = self.block_details(to).expect("to hash is invalid!"); + + let mut current_from = from.clone(); + let mut current_to = to.clone(); + + // reset from && to to the same level + while from_details.number > to_details.number { + from_branch.push(current_from); + current_from = from_details.parent.clone(); + from_details = self.block_details(&from_details.parent).unwrap(); + } + + while to_details.number > from_details.number { + to_branch.push(current_to); + current_to = to_details.parent.clone(); + to_details = self.block_details(&to_details.parent).unwrap(); + } + + assert_eq!(from_details.number, to_details.number); + + // move to shared parent + while from_details.parent != to_details.parent { + from_branch.push(current_from); + current_from = from_details.parent.clone(); + from_details = self.block_details(&from_details.parent).unwrap(); + + to_branch.push(current_to); + current_to = to_details.parent.clone(); + to_details = self.block_details(&to_details.parent).unwrap(); + } + + let index = from_branch.len(); + + from_branch.extend(to_branch.iter().rev()); + + TreeRoute { + blocks: from_branch, + ancestor: from_details.parent, + index: index + } + } + /// Inserts the block into backing cache database. /// Expects the block to be valid and already verified. /// If the block is already known, does nothing. pub fn insert_block(&self, bytes: &[u8]) { + // create views onto rlp let block = BlockView::new(bytes); let header = block.header_view(); @@ -107,20 +226,65 @@ impl BlockChain { return; } + // prepare variables let hash = block.sha3(); + let mut parent_details = self.block_details(&header.parent_hash()).expect("Invalid parent hash."); + let total_difficulty = parent_details.total_difficulty + header.difficulty(); + + // create current block details + let details = BlockDetails { + number: header.number(), + total_difficulty: total_difficulty, + parent: header.parent_hash(), + children: vec![] + }; + // store block in db self.blocks_db.put(&hash, &bytes).unwrap(); - let batch = WriteBatch::new(); - batch.put_extras(&hash, &block.block_details()); - batch.put_extras(&header.number(), &hash); - self.extras_db.write(batch).unwrap(); + // update extra details + { + // insert new block details + let batch = WriteBatch::new(); + batch.put_extras(&hash, &details); + + // update parent details + parent_details.children.push(hash.clone()); + batch.put_extras(&header.parent_hash(), &parent_details); + self.extras_db.write(batch).unwrap(); + } + + // check if we have new best block. + // if yes, it means that we need to move it and its ancestors + // to "canon chain" + if total_difficulty > self.best_block_total_difficulty() { + + // find the route between old best block and the new one + let route = self.tree_route(&self.best_block_hash(), &hash); + let ancestor_number = self.block_number(&route.ancestor).unwrap(); + let start_number = ancestor_number + U256::from(1u8); + let extras_batch = route.blocks.iter() + .skip(route.index) + .enumerate() + .fold(WriteBatch::new(), | acc, (index, hash) | { + acc.put_extras(&(start_number + U256::from(index as u64)), hash); + acc + }); + + // update extras database + extras_batch.put(b"best", &hash).unwrap(); + self.extras_db.write(extras_batch).unwrap(); + + // update local caches + self.best_block_hash.set(hash); + self.best_block_number.set(header.number()); + self.best_block_total_difficulty.set(total_difficulty); + } } /// Returns true if the given block is known /// (though not necessarily a part of the canon chain). pub fn is_known(&self, hash: &H256) -> bool { - // TODO: consider taking into account current block self.query_extras_exist(hash, &self.block_details) } @@ -173,9 +337,19 @@ impl BlockChain { self.query_extras(hash, &self.block_hashes) } - /// Get last block number - pub fn last_block_number(&self) -> U256 { - self.last_block_number.get() + /// Get best block hash + pub fn best_block_hash(&self) -> H256 { + self.best_block_hash.get() + } + + /// Get best block number + pub fn best_block_number(&self) -> U256 { + self.best_block_number.get() + } + + /// Get best block total difficulty + pub fn best_block_total_difficulty(&self) -> U256 { + self.best_block_total_difficulty.get() } /// Get the number of given block's hash diff --git a/src/genesis.rs b/src/genesis.rs index 862abd117..735039079 100644 --- a/src/genesis.rs +++ b/src/genesis.rs @@ -96,6 +96,17 @@ impl Genesis { } } + /// Returns genesis block + pub fn block(&self) -> &[u8] { + &self.block + } + + /// Returns genesis block state + pub fn state(&self) -> &HashMap { + &self.state + } + + // not sure if this one is needed pub fn drain(self) -> (Vec, HashMap) { (self.block, self.state) } diff --git a/src/views.rs b/src/views.rs index 23ac7741e..562f6c690 100644 --- a/src/views.rs +++ b/src/views.rs @@ -6,7 +6,6 @@ use util::rlp::*; use util::sha3::*; use blockheader::*; use transaction::*; -use extras::*; /// View onto block rlp. pub struct BlockView<'a> { @@ -62,19 +61,6 @@ impl<'a> BlockView<'a> { pub fn uncle_hashes(&self) -> Vec { self.rlp.at(2).iter().map(|rlp| rlp.raw().sha3()).collect() } - - /// Return BlockDetaile object of given block - /// note* children is always an empty vector, - /// cause we can't deducate them from rlp. - pub fn block_details(&self) -> BlockDetails { - let header = self.header_view(); - BlockDetails { - number: header.number(), - total_difficulty: header.difficulty(), - parent: header.parent_hash(), - children: vec![] - } - } } impl<'a> Hashable for BlockView<'a> {