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use alloc::vec::Vec; use alloc::collections::BTreeMap; use primitive_types::{H160, H256, U256}; use sha3::{Digest, Keccak256}; use super::{Basic, Backend, ApplyBackend, Apply, Log}; #[derive(Clone, Debug, Eq, PartialEq)] pub struct MemoryVicinity { pub gas_price: U256, pub origin: H160, pub chain_id: U256, pub block_hashes: Vec<H256>, pub block_number: U256, pub block_coinbase: H160, pub block_timestamp: U256, pub block_difficulty: U256, pub block_gas_limit: U256, } #[derive(Default, Clone, Debug, Eq, PartialEq)] pub struct MemoryAccount { pub nonce: U256, pub balance: U256, pub storage: BTreeMap<H256, H256>, pub code: Vec<u8>, } #[derive(Clone, Debug)] pub struct MemoryBackend<'vicinity> { vicinity: &'vicinity MemoryVicinity, state: BTreeMap<H160, MemoryAccount>, logs: Vec<Log>, } impl<'vicinity> MemoryBackend<'vicinity> { pub fn new(vicinity: &'vicinity MemoryVicinity, state: BTreeMap<H160, MemoryAccount>) -> Self { Self { vicinity, state, logs: Vec::new(), } } pub fn state(&self) -> &BTreeMap<H160, MemoryAccount> { &self.state } } impl<'vicinity> Backend for MemoryBackend<'vicinity> { fn gas_price(&self) -> U256 { self.vicinity.gas_price } fn origin(&self) -> H160 { self.vicinity.origin } fn block_hash(&self, number: U256) -> H256 { if number >= self.vicinity.block_number || self.vicinity.block_number - number - U256::one() >= U256::from(self.vicinity.block_hashes.len()) { H256::default() } else { let index = (self.vicinity.block_number - number - U256::one()).as_usize(); self.vicinity.block_hashes[index] } } fn block_number(&self) -> U256 { self.vicinity.block_number } fn block_coinbase(&self) -> H160 { self.vicinity.block_coinbase } fn block_timestamp(&self) -> U256 { self.vicinity.block_timestamp } fn block_difficulty(&self) -> U256 { self.vicinity.block_difficulty } fn block_gas_limit(&self) -> U256 { self.vicinity.block_gas_limit } fn chain_id(&self) -> U256 { self.vicinity.chain_id } fn exists(&self, address: H160) -> bool { self.state.contains_key(&address) } fn basic(&self, address: H160) -> Basic { self.state.get(&address).map(|a| { Basic { balance: a.balance, nonce: a.nonce } }).unwrap_or_default() } fn code_hash(&self, address: H160) -> H256 { self.state.get(&address).map(|v| { H256::from_slice(Keccak256::digest(&v.code).as_slice()) }).unwrap_or(H256::from_slice(Keccak256::digest(&[]).as_slice())) } fn code_size(&self, address: H160) -> usize { self.state.get(&address).map(|v| v.code.len()).unwrap_or(0) } fn code(&self, address: H160) -> Vec<u8> { self.state.get(&address).map(|v| v.code.clone()).unwrap_or_default() } fn storage(&self, address: H160, index: H256) -> H256 { self.state.get(&address) .map(|v| v.storage.get(&index).cloned().unwrap_or(H256::default())) .unwrap_or(H256::default()) } } impl<'vicinity> ApplyBackend for MemoryBackend<'vicinity> { fn apply<A, I, L>( &mut self, values: A, logs: L, delete_empty: bool, ) where A: IntoIterator<Item=Apply<I>>, I: IntoIterator<Item=(H256, H256)>, L: IntoIterator<Item=Log>, { for apply in values { match apply { Apply::Modify { address, basic, code, storage, reset_storage, } => { let is_empty = { let account = self.state.entry(address).or_insert(Default::default()); account.balance = basic.balance; account.nonce = basic.nonce; if let Some(code) = code { account.code = code; } if reset_storage { account.storage = BTreeMap::new(); } let zeros = account.storage.iter() .filter(|(_, v)| v == &&H256::default()) .map(|(k, _)| k.clone()) .collect::<Vec<H256>>(); for zero in zeros { account.storage.remove(&zero); } for (index, value) in storage { if value == H256::default() { account.storage.remove(&index); } else { account.storage.insert(index, value); } } account.balance == U256::zero() && account.nonce == U256::zero() && account.code.len() == 0 }; if is_empty && delete_empty { self.state.remove(&address); } }, Apply::Delete { address, } => { self.state.remove(&address); }, } } for log in logs { self.logs.push(log); } } }