139 lines
3.5 KiB
Rust
139 lines
3.5 KiB
Rust
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use util::rlp::*;
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use util::hash::{H256, H2048};
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use util::uint::{U256};
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use util::bytes::Bytes;
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use header::{BlockNumber, Header};
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use transaction::SignedTransaction;
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/// Chain iterator interface.
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pub trait ChainIterator: Iterator {
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/// Should be called to create a fork of current iterator.
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/// Blocks generated by fork will have lower difficulty than current chain.
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fn fork(&mut self) -> Self;
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/// Should be called to create new block with given bloom.
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fn next_with_bloom(&mut self, bloom: H2048) -> Option<Self::Item>;
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}
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/// Helper structure, used for encoding blocks.
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#[derive(Default)]
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struct Block {
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header: Header,
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transactions: Vec<SignedTransaction>,
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uncles: Vec<Header>
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}
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impl Encodable for Block {
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fn rlp_append(&self, s: &mut RlpStream) {
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s.begin_list(3);
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s.append(&self.header);
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s.append(&self.transactions);
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s.append(&self.uncles);
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}
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}
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/// Blockchain generator.
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pub struct ChainGenerator {
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/// Next block number.
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number: BlockNumber,
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/// Next block parent hash.
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parent_hash: H256,
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/// Next block difficulty.
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difficulty: U256,
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/// Number of forks of current block.
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number_of_forks: usize,
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}
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impl ChainGenerator {
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fn prepare_block(&self) -> Block {
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let mut block = Block::default();
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block.header.parent_hash = self.parent_hash.clone();
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block.header.number = self.number;
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block.header.difficulty = self.difficulty;
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block
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}
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}
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impl Default for ChainGenerator {
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fn default() -> Self {
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ChainGenerator {
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number: 0,
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parent_hash: H256::default(),
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difficulty: U256::from(1000),
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number_of_forks: 0
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}
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}
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}
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impl Iterator for ChainGenerator {
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type Item = Bytes;
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fn next(&mut self) -> Option<Self::Item> {
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let block = self.prepare_block();
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self.number += 1;
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self.parent_hash = block.header.hash();
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self.number_of_forks = 0;
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Some(encode(&block).to_vec())
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}
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}
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impl ChainIterator for ChainGenerator {
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fn fork(&mut self) -> Self {
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self.number_of_forks += 1;
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ChainGenerator {
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number: self.number,
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parent_hash: self.parent_hash.clone(),
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difficulty: self.difficulty - U256::from(self.number_of_forks),
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number_of_forks: 0
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}
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}
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fn next_with_bloom(&mut self, bloom: H2048) -> Option<Self::Item> {
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let mut block = self.prepare_block();
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block.header.log_bloom = bloom;
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self.number += 1;
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self.parent_hash = block.header.hash();
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self.number_of_forks = 0;
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Some(encode(&block).to_vec())
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}
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}
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#[cfg(test)]
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mod tests {
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use util::hash::H256;
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use util::sha3::Hashable;
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use views::BlockView;
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use super::{ChainIterator, ChainGenerator};
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#[test]
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fn canon_chain_generator() {
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let mut canon_chain = ChainGenerator::default();
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let genesis_rlp = canon_chain.next().unwrap();
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let genesis = BlockView::new(&genesis_rlp);
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assert_eq!(genesis.header_view().parent_hash(), H256::default());
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assert_eq!(genesis.header_view().number(), 0);
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let b1_rlp = canon_chain.next().unwrap();
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let b1 = BlockView::new(&b1_rlp);
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assert_eq!(b1.header_view().parent_hash(), genesis.header_view().sha3());
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assert_eq!(b1.header_view().number(), 1);
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let mut fork_chain = canon_chain.fork();
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let b2_rlp_fork = fork_chain.next().unwrap();
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let b2_fork = BlockView::new(&b2_rlp_fork);
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assert_eq!(b2_fork.header_view().parent_hash(), b1.header_view().sha3());
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assert_eq!(b2_fork.header_view().number(), 2);
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let b2_rlp = canon_chain.next().unwrap();
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let b2 = BlockView::new(&b2_rlp);
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assert_eq!(b2.header_view().parent_hash(), b1.header_view().sha3());
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assert_eq!(b2.header_view().number(), 2);
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assert!(b2.header_view().difficulty() > b2_fork.header_view().difficulty());
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}
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}
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