openethereum/src/state.rs

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use std::collections::HashMap;
use util::hash::*;
use util::hashdb::*;
use util::overlaydb::*;
use util::trie::*;
use util::rlp::*;
use util::uint::*;
use std::mem;
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use account::Account;
/*
enum ValueOrRef<'self, 'db: 'self> {
Value(OverlayDB),
Ref(&'db mut OverlayDB)
}
impl<'self, 'db> ValueOrRef<'self, 'db: 'self> {
pub fn get_mut(&mut self) -> &mut OverlayDB {
match self {
Value(ref mut x) => x,
Ref(x) => x,
}
}
pub fn get(&self) -> &OverlayDB {
match self {
Value(ref x) => x,
Ref(x) => x,
}
}
}
*/
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/// Representation of the entire state of all accounts in the system.
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pub struct State {
db: OverlayDB,
root: H256,
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cache: HashMap<Address, Option<Account>>,
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_account_start_nonce: U256,
}
impl State {
/// Creates new state with empty state root
pub fn new(mut db: OverlayDB, account_start_nonce: U256) -> State {
let mut root = H256::new();
{
// init trie and reset root too null
let _ = TrieDB::new(&mut db, &mut root);
}
State {
db: db,
root: root,
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cache: HashMap::new(),
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_account_start_nonce: account_start_nonce,
}
}
/// Creates new state with existing state root
pub fn new_existing(mut db: OverlayDB, mut root: H256, account_start_nonce: U256) -> State {
{
// trie should panic! if root does not exist
let _ = TrieDB::new_existing(&mut db, &mut root);
}
State {
db: db,
root: root,
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cache: HashMap::new(),
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_account_start_nonce: account_start_nonce,
}
}
/// Create temporary state object
pub fn new_temp() -> State {
Self::new(OverlayDB::new_temp(), U256::from(0u8))
}
/// Return reference to root
pub fn root(&self) -> &H256 {
&self.root
}
/// Desttroy the current database and return it.
/// WARNING: the struct should be dropped immediately following this.
pub fn take_db(&mut self) -> OverlayDB {
mem::replace(&mut self.db, OverlayDB::new_temp())
}
/// Destroy the current object and return root and database.
pub fn drop(mut self) -> (H256, OverlayDB) {
(mem::replace(&mut self.root, H256::new()), mem::replace(&mut self.db, OverlayDB::new_temp()))
}
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/// Expose the underlying database; good to use for calling `state.db().commit()`.
pub fn db(&mut self) -> &mut OverlayDB {
&mut self.db
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}
/// Get the balance of account `a`.
// TODO: make immutable
pub fn balance(&mut self, a: &Address) -> U256 {
self.get(a, false).as_ref().map(|account| account.balance().clone()).unwrap_or(U256::from(0u8))
}
/// Add `incr` to the balance of account `a`.
pub fn add_balance(&mut self, a: &Address, incr: &U256) {
self.require(a, false).add_balance(incr)
}
/// Subtract `decr` from the balance of account `a`.
pub fn sub_balance(&mut self, a: &Address, decr: &U256) {
self.require(a, false).sub_balance(decr)
}
/// Get the nonce of account `a`.
// TODO: make immutable
pub fn nonce(&mut self, a: &Address) -> U256 {
self.get(a, false).as_ref().map(|account| account.nonce().clone()).unwrap_or(U256::from(0u8))
}
/// Increment the nonce of account `a` by 1.
pub fn inc_nonce(&mut self, a: &Address) {
self.require(a, false).inc_nonce()
}
/// Commit accounts to TrieDB. This is similar to cpp-ethereum's dev::eth::commit.
/// `accounts` is mutable because we may need to commit the code or storage and record that.
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pub fn commit_into(db: &mut HashDB, mut root: H256, accounts: &mut HashMap<Address, Option<Account>>) -> H256 {
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// first, commit the sub trees.
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// TODO: is this necessary or can we dispense with the `ref mut a` for just `a`?
for (_, ref mut a) in accounts.iter_mut() {
match a {
&mut&mut Some(ref mut account) => {
account.commit_storage(db);
account.commit_code(db);
}
&mut&mut None => {}
}
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}
{
let mut trie = TrieDB::new_existing(db, &mut root);
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for (address, ref a) in accounts.iter() {
match a {
&&Some(ref account) => trie.insert(address, &account.rlp()),
&&None => trie.remove(address),
}
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}
}
root
}
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/// Commits our cached account changes into the trie.
pub fn commit(&mut self) {
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let r = self.root.clone(); // would prefer not to do this, really.
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self.root = Self::commit_into(&mut self.db, r, &mut self.cache);
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}
/// Pull account `a` in our cache from the trie DB. `require_code` requires that the code be cached, too.
/// `force_create` creates a new, empty basic account if there is not currently an active account.
// TODO: make immutable.
fn get(&mut self, a: &Address, require_code: bool) -> Option<&mut Account> {
if self.cache.get(a).is_none() {
// load from trie.
let t = TrieDB::new_existing(&mut self.db, &mut self.root);
self.cache.insert(a.clone(), t.at(&a).map(|rlp| { println!("RLP: {:?}", rlp); Account::from_rlp(rlp) }));
}
let db = &self.db;
self.cache.get_mut(a).unwrap().as_mut().map(|account| {
if require_code {
account.cache_code(db);
}
account
})
}
/// Pull account `a` in our cache from the trie DB. `require_code` requires that the code be cached, too.
/// `force_create` creates a new, empty basic account if there is not currently an active account.
fn require(&mut self, a: &Address, require_code: bool) -> &mut Account {
if self.cache.get(a).is_none() {
// load from trie.
self.cache.insert(a.clone(), TrieDB::new(&mut self.db, &mut self.root).at(&a).map(|rlp| Account::from_rlp(rlp)));
}
if self.cache.get(a).unwrap().is_none() {
self.cache.insert(a.clone(), Some(Account::new_basic(U256::from(0u8))));
}
let db = &self.db;
self.cache.get_mut(a).unwrap().as_mut().map(|account| {
if require_code {
account.cache_code(db);
}
account
}).unwrap()
}
}
#[cfg(test)]
mod tests {
use super::*;
use util::hash::*;
use util::trie::*;
use util::rlp::*;
use util::uint::*;
use std::str::FromStr;
#[test]
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fn get_from_database() {
let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
let (r, db) = {
let mut s = State::new_temp();
s.inc_nonce(&a);
s.add_balance(&a, &U256::from(69u64));
s.commit();
assert_eq!(s.balance(&a), U256::from(69u64));
(s.root().clone(), s.take_db())
};
let mut s = State::new_existing(db, r, U256::from(0u8));
assert_eq!(s.balance(&a), U256::from(69u64));
assert_eq!(s.nonce(&a), U256::from(1u64));
}
#[test]
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fn alter_balance() {
let mut s = State::new_temp();
let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
s.add_balance(&a, &U256::from(69u64));
assert_eq!(s.balance(&a), U256::from(69u64));
s.commit();
assert_eq!(s.balance(&a), U256::from(69u64));
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s.sub_balance(&a, &U256::from(42u64));
assert_eq!(s.balance(&a), U256::from(27u64));
s.commit();
assert_eq!(s.balance(&a), U256::from(27u64));
}
#[test]
fn alter_nonce() {
let mut s = State::new_temp();
let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
s.inc_nonce(&a);
assert_eq!(s.nonce(&a), U256::from(1u64));
s.inc_nonce(&a);
assert_eq!(s.nonce(&a), U256::from(2u64));
s.commit();
assert_eq!(s.nonce(&a), U256::from(2u64));
s.inc_nonce(&a);
assert_eq!(s.nonce(&a), U256::from(3u64));
s.commit();
assert_eq!(s.nonce(&a), U256::from(3u64));
}
#[test]
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fn balance_nonce() {
let mut s = State::new_temp();
let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
assert_eq!(s.balance(&a), U256::from(0u64));
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assert_eq!(s.nonce(&a), U256::from(0u64));
s.commit();
assert_eq!(s.balance(&a), U256::from(0u64));
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assert_eq!(s.nonce(&a), U256::from(0u64));
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}
#[test]
fn ensure_cached() {
let mut s = State::new_temp();
let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
s.require(&a, false);
s.commit();
assert_eq!(s.root().hex(), "ec68b85fa2e0526dc0e821a5b33135459114f19173ce0479f5c09b21cc25b9a4");
}
#[test]
fn create_empty() {
let mut s = State::new_temp();
s.commit();
assert_eq!(s.root().hex(), "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421");
}
}