openethereum/ethcore/blockchain/src/generator.rs

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// Copyright 2015-2019 Parity Technologies (UK) Ltd.
// This file is part of Parity Ethereum.
// Parity Ethereum 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 Ethereum 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 Ethereum. If not, see <http://www.gnu.org/licenses/>.
//! Blockchain generator for tests.
use std::collections::VecDeque;
use ethereum_types::{U256, H256, Bloom};
use common_types::encoded;
use common_types::header::Header;
use common_types::transaction::{SignedTransaction, Transaction, Action};
use common_types::view;
use common_types::views::BlockView;
use keccak_hash::keccak;
use rlp::encode;
use rlp_derive::RlpEncodable;
use triehash_ethereum::ordered_trie_root;
/// Helper structure, used for encoding blocks.
#[derive(Default, Clone, RlpEncodable)]
pub struct Block {
/// Block header
pub header: Header,
/// Block transactions
pub transactions: Vec<SignedTransaction>,
/// Block uncles
pub uncles: Vec<Header>
}
impl Block {
/// Get a copy of the header
#[inline]
pub fn header(&self) -> Header {
self.header.clone()
}
/// Get block hash
#[inline]
pub fn hash(&self) -> H256 {
view!(BlockView, &self.encoded().raw()).header_view().hash()
}
/// Get block number
#[inline]
pub fn number(&self) -> u64 {
self.header.number()
}
/// Get RLP encoding of this block
#[inline]
pub fn encoded(&self) -> encoded::Block {
encoded::Block::new(encode(self))
}
/// Get block difficulty
#[inline]
pub fn difficulty(&self) -> U256 {
*self.header.difficulty()
}
}
/// Specify block options for generator
#[derive(Debug)]
pub struct BlockOptions {
/// Difficulty
pub difficulty: U256,
/// Set bloom filter
pub bloom: Bloom,
/// Transactions included in blocks
pub transactions: Vec<SignedTransaction>,
}
impl Default for BlockOptions {
fn default() -> Self {
BlockOptions {
difficulty: 10.into(),
bloom: Bloom::default(),
transactions: Vec::new(),
}
}
}
/// Utility to create blocks
#[derive(Clone)]
pub struct BlockBuilder {
blocks: VecDeque<Block>,
}
impl BlockBuilder {
/// Create new BlockBuilder starting at genesis.
pub fn genesis() -> Self {
let mut blocks = VecDeque::with_capacity(1);
blocks.push_back(Block::default());
BlockBuilder {
blocks,
}
}
/// Add new block with default options.
#[inline]
pub fn add_block(&self) -> Self {
self.add_block_with(|| BlockOptions::default())
}
/// Add `count` number of blocks with default options.
#[inline]
pub fn add_blocks(&self, count: usize) -> Self {
self.add_blocks_with(count, || BlockOptions::default())
}
/// Add block with specified options.
#[inline]
pub fn add_block_with<T>(&self, get_metadata: T) -> Self where T: Fn() -> BlockOptions {
self.add_blocks_with(1, get_metadata)
}
/// Add a block with given difficulty
#[inline]
pub fn add_block_with_difficulty<T>(&self, difficulty: T) -> Self where T: Into<U256> {
let difficulty = difficulty.into();
self.add_blocks_with(1, move || BlockOptions {
difficulty,
..Default::default()
})
}
/// Add a block with randomly generated transactions.
#[inline]
pub fn add_block_with_random_transactions(&self) -> Self {
// Maximum of ~50 transactions
let count = rand::random::<u8>() as usize / 5;
let transactions = std::iter::repeat_with(|| {
let data_len = rand::random::<u8>();
let data = std::iter::repeat_with(|| rand::random::<u8>())
.take(data_len as usize)
.collect::<Vec<_>>();
Transaction {
nonce: 0.into(),
gas_price: 0.into(),
gas: 100_000.into(),
action: Action::Create,
value: 100.into(),
data,
}.sign(&keccak("").into(), None)
}).take(count);
self.add_block_with_transactions(transactions)
}
/// Add a block with given transactions.
#[inline]
pub fn add_block_with_transactions<T>(&self, transactions: T) -> Self
where T: IntoIterator<Item = SignedTransaction> {
let transactions = transactions.into_iter().collect::<Vec<_>>();
self.add_blocks_with(1, || BlockOptions {
transactions: transactions.clone(),
..Default::default()
})
}
/// Add a block with given bloom filter.
#[inline]
pub fn add_block_with_bloom(&self, bloom: Bloom) -> Self {
self.add_blocks_with(1, move || BlockOptions {
bloom,
..Default::default()
})
}
/// Add a bunch of blocks with given metadata.
pub fn add_blocks_with<T>(&self, count: usize, get_metadata: T) -> Self where T: Fn() -> BlockOptions {
assert!(count > 0, "There must be at least 1 block");
let mut parent_hash = self.last().hash();
let mut parent_number = self.last().number();
let mut blocks = VecDeque::with_capacity(count);
for _ in 0..count {
let mut block = Block::default();
let metadata = get_metadata();
let block_number = parent_number + 1;
let transactions = metadata.transactions;
let transactions_root = ordered_trie_root(transactions.iter().map(rlp::encode));
block.header.set_parent_hash(parent_hash);
block.header.set_number(block_number);
block.header.set_log_bloom(metadata.bloom);
block.header.set_difficulty(metadata.difficulty);
block.header.set_transactions_root(transactions_root);
block.transactions = transactions;
parent_hash = block.hash();
parent_number = block_number;
blocks.push_back(block);
}
BlockBuilder {
blocks,
}
}
/// Get a reference to the last generated block.
#[inline]
pub fn last(&self) -> &Block {
self.blocks.back().expect("There is always at least 1 block")
}
}
/// Generates a blockchain from given block builders (blocks will be concatenated).
#[derive(Clone)]
pub struct BlockGenerator {
builders: VecDeque<BlockBuilder>,
}
impl BlockGenerator {
/// Create new block generator.
pub fn new<T>(builders: T) -> Self where T: IntoIterator<Item = BlockBuilder> {
BlockGenerator {
builders: builders.into_iter().collect(),
}
}
}
impl Iterator for BlockGenerator {
type Item = Block;
fn next(&mut self) -> Option<Self::Item> {
loop {
match self.builders.front_mut() {
Some(ref mut builder) => {
if let Some(block) = builder.blocks.pop_front() {
return Some(block);
}
},
None => return None,
}
self.builders.pop_front();
}
}
}
#[cfg(test)]
mod tests {
use super::{BlockBuilder, BlockOptions, BlockGenerator};
#[test]
fn test_block_builder() {
let genesis = BlockBuilder::genesis();
let block_1 = genesis.add_block();
let block_1001 = block_1.add_blocks(1000);
let block_1002 = block_1001.add_block_with(|| BlockOptions::default());
let generator = BlockGenerator::new(vec![genesis, block_1, block_1001, block_1002]);
assert_eq!(generator.count(), 1003);
}
#[test]
fn test_block_builder_fork() {
let genesis = BlockBuilder::genesis();
let block_10a = genesis.add_blocks(10);
let block_11b = genesis.add_blocks(11);
assert_eq!(block_10a.last().number(), 10);
assert_eq!(block_11b.last().number(), 11);
}
}