State copy optimization

ethcore/src/block.rs

@@ -62,7 +62,7 @@ impl Decodable for Block {
 /// Internal type for a block's common elements.
 // TODO: rename to ExecutedBlock
 // TODO: use BareBlock
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub struct ExecutedBlock {
 	base: Block,
 
@@ -318,8 +318,8 @@ impl IsBlock for SealedBlock {
 /// Enact the block given by block header, transactions and uncles
 pub fn enact<'x, 'y>(header: &Header, transactions: &[Transaction], uncles: &[Header], engine: &'x Engine, db: JournalDB, parent: &Header, last_hashes: &'y LastHashes) -> Result<ClosedBlock<'x, 'y>, Error> {
 	{
-		let s = State::from_existing(db.clone(), parent.state_root().clone(), engine.account_start_nonce());
+		//let s = State::from_existing(db.clone(), parent.state_root().clone(), engine.account_start_nonce());
-		trace!("enact(): root={}, author={}, author_balance={}\n", s.root(), header.author(), s.balance(&header.author()));
+		//trace!("enact(): root={}, author={}, author_balance={}\n", s.root(), header.author(), s.balance(&header.author()));
 	}
 
 	let mut b = OpenBlock::new(engine, db, parent, last_hashes, header.author().clone(), header.extra_data().clone());
@@ -363,10 +363,10 @@ mod tests {
 		let engine = Spec::new_test().to_engine().unwrap();
 		let genesis_header = engine.spec().genesis_header();
 		let mut db_result = get_temp_journal_db();
-		let db = db_result.reference_mut();
+		let mut db = db_result.take();
-		engine.spec().ensure_db_good(db);
+		engine.spec().ensure_db_good(&mut db);
 		let last_hashes = vec![genesis_header.hash()];
-		let b = OpenBlock::new(engine.deref(), db.clone(), &genesis_header, &last_hashes, Address::zero(), vec![]);
+		let b = OpenBlock::new(engine.deref(), db, &genesis_header, &last_hashes, Address::zero(), vec![]);
 		let b = b.close();
 		let _ = b.seal(vec![]);
 	}
@@ -378,16 +378,16 @@ mod tests {
 		let genesis_header = engine.spec().genesis_header();
 
 		let mut db_result = get_temp_journal_db();
-		let db = db_result.reference_mut();
+		let mut db = db_result.take();
-		engine.spec().ensure_db_good(db);
+		engine.spec().ensure_db_good(&mut db);
-		let b = OpenBlock::new(engine.deref(), db.clone(), &genesis_header, &vec![genesis_header.hash()], Address::zero(), vec![]).close().seal(vec![]).unwrap();
+		let b = OpenBlock::new(engine.deref(), db, &genesis_header, &vec![genesis_header.hash()], Address::zero(), vec![]).close().seal(vec![]).unwrap();
 		let orig_bytes = b.rlp_bytes();
 		let orig_db = b.drain();
 
 		let mut db_result = get_temp_journal_db();
-		let db = db_result.reference_mut();
+		let mut db = db_result.take();
-		engine.spec().ensure_db_good(db);
+		engine.spec().ensure_db_good(&mut db);
-		let e = enact_and_seal(&orig_bytes, engine.deref(), db.clone(), &genesis_header, &vec![genesis_header.hash()]).unwrap();
+		let e = enact_and_seal(&orig_bytes, engine.deref(), db, &genesis_header, &vec![genesis_header.hash()]).unwrap();
 
 		assert_eq!(e.rlp_bytes(), orig_bytes);
 

ethcore/src/client.rs

@@ -139,7 +139,7 @@ impl ClientReport {
 pub struct Client {
 	chain: Arc<RwLock<BlockChain>>,
 	engine: Arc<Box<Engine>>,
-	state_db: JournalDB,
+	state_db: Arc<DB>,
 	block_queue: RwLock<BlockQueue>,
 	report: RwLock<ClientReport>,
 	uncommited_states: RwLock<HashMap<H256, JournalDB>>,
@@ -186,7 +186,7 @@ impl Client {
 		Ok(Arc::new(Client {
 			chain: chain,
 			engine: engine.clone(),
-			state_db: state_db,
+			state_db: db,
 			block_queue: RwLock::new(BlockQueue::new(engine, message_channel)),
 			report: RwLock::new(Default::default()),
 			uncommited_states: RwLock::new(HashMap::new()),
@@ -242,7 +242,7 @@ impl Client {
 				}
 			}
 
-			let db = self.state_db.clone();
+			let db = JournalDB::new_with_arc(self.state_db.clone());
 			let result = match enact_verified(&block, self.engine.deref().deref(), db, &parent, &last_hashes) {
 				Ok(b) => b,
 				Err(e) => {
@@ -284,7 +284,7 @@ impl Client {
 
 	/// Get a copy of the best block's state.
 	pub fn state(&self) -> State {
-		State::from_existing(self.state_db.clone(), HeaderView::new(&self.best_block_header()).state_root(), self.engine.account_start_nonce())
+		State::from_existing(JournalDB::new_with_arc(self.state_db.clone()), HeaderView::new(&self.best_block_header()).state_root(), self.engine.account_start_nonce())
 	}
 
 	/// Get info on the cache.

ethcore/src/ethereum/ethash.rs

@@ -232,10 +232,10 @@ fn on_close_block() {
 	let engine = new_morden().to_engine().unwrap();
 	let genesis_header = engine.spec().genesis_header();
 	let mut db_result = get_temp_journal_db();
-	let mut db = db_result.reference_mut();
+	let mut db = db_result.take();
-	engine.spec().ensure_db_good(db);
+	engine.spec().ensure_db_good(&mut db);
 	let last_hashes = vec![genesis_header.hash()];
-	let b = OpenBlock::new(engine.deref(), db.clone(), &genesis_header, &last_hashes, Address::zero(), vec![]);
+	let b = OpenBlock::new(engine.deref(), db, &genesis_header, &last_hashes, Address::zero(), vec![]);
 	let b = b.close();
 	assert_eq!(b.state().balance(&Address::zero()), U256::from_str("4563918244f40000").unwrap());
 }
@@ -246,10 +246,10 @@ fn on_close_block_with_uncle() {
 	let engine = new_morden().to_engine().unwrap();
 	let genesis_header = engine.spec().genesis_header();
 	let mut db_result = get_temp_journal_db();
-	let mut db = db_result.reference_mut();
+	let mut db = db_result.take();
-	engine.spec().ensure_db_good(db);
+	engine.spec().ensure_db_good(&mut db);
 	let last_hashes = vec![genesis_header.hash()];
-	let mut b = OpenBlock::new(engine.deref(), db.clone(), &genesis_header, &last_hashes, Address::zero(), vec![]);
+	let mut b = OpenBlock::new(engine.deref(), db, &genesis_header, &last_hashes, Address::zero(), vec![]);
 	let mut uncle = Header::new();
 	let uncle_author = address_from_hex("ef2d6d194084c2de36e0dabfce45d046b37d1106");
 	uncle.author = uncle_author.clone();

ethcore/src/ethereum/mod.rs

@@ -44,9 +44,9 @@ mod tests {
 		let engine = new_morden().to_engine().unwrap();
 		let genesis_header = engine.spec().genesis_header();
 		let mut db_result = get_temp_journal_db();
-		let mut db = db_result.reference_mut();
+		let mut db = db_result.take();
-		engine.spec().ensure_db_good(db);
+		engine.spec().ensure_db_good(&mut db);
-		let s = State::from_existing(db.clone(), genesis_header.state_root.clone(), engine.account_start_nonce());
+		let s = State::from_existing(db, genesis_header.state_root.clone(), engine.account_start_nonce());
 		assert_eq!(s.balance(&address_from_hex("0000000000000000000000000000000000000001")), U256::from(1u64));
 		assert_eq!(s.balance(&address_from_hex("0000000000000000000000000000000000000002")), U256::from(1u64));
 		assert_eq!(s.balance(&address_from_hex("0000000000000000000000000000000000000003")), U256::from(1u64));

ethcore/src/executive.rs

@@ -194,7 +194,7 @@ impl<'a> Executive<'a> {
 	/// Returns either gas_left or `evm::Error`.
 	pub fn call(&mut self, params: ActionParams, substate: &mut Substate, mut output: BytesRef) -> evm::Result {
 		// backup used in case of running out of gas
-		let backup = self.state.clone();
+		self.state.snapshot();
 
 		// at first, transfer value to destination
 		if let ActionValue::Transfer(val) = params.value {
@@ -212,11 +212,12 @@ impl<'a> Executive<'a> {
 			match cost <= params.gas {
 				true => {
 					self.engine.execute_builtin(&params.code_address, data, &mut output);
+					self.state.clear_snapshot();
 					Ok(params.gas - cost)
 				},
 				// just drain the whole gas
 				false => {
-					self.state.revert(backup);
+					self.state.revert_snapshot();
 					Err(evm::Error::OutOfGas)
 				}
 			}
@@ -232,11 +233,12 @@ impl<'a> Executive<'a> {
 
 			trace!("exec: sstore-clears={}\n", unconfirmed_substate.sstore_clears_count);
 			trace!("exec: substate={:?}; unconfirmed_substate={:?}\n", substate, unconfirmed_substate);
-			self.enact_result(&res, substate, unconfirmed_substate, backup);
+			self.enact_result(&res, substate, unconfirmed_substate);
 			trace!("exec: new substate={:?}\n", substate);
 			res
 		} else {
 			// otherwise, nothing
+			self.state.clear_snapshot();
 			Ok(params.gas)
 		}
 	}
@@ -246,7 +248,7 @@ impl<'a> Executive<'a> {
 	/// Modifies the substate.
 	pub fn create(&mut self, params: ActionParams, substate: &mut Substate) -> evm::Result {
 		// backup used in case of running out of gas
-		let backup = self.state.clone();
+		self.state.snapshot();
 
 		// part of substate that may be reverted
 		let mut unconfirmed_substate = Substate::new();
@@ -263,7 +265,7 @@ impl<'a> Executive<'a> {
 		let res = {
 			self.exec_vm(params, &mut unconfirmed_substate, OutputPolicy::InitContract)
 		};
-		self.enact_result(&res, substate, unconfirmed_substate, backup);
+		self.enact_result(&res, substate, unconfirmed_substate);
 		res
 	}
 
@@ -324,16 +326,19 @@ impl<'a> Executive<'a> {
 		}
 	}
 
-	fn enact_result(&mut self, result: &evm::Result, substate: &mut Substate, un_substate: Substate, backup: State) {
+	fn enact_result(&mut self, result: &evm::Result, substate: &mut Substate, un_substate: Substate) {
 		match *result {
 			Err(evm::Error::OutOfGas)
 				| Err(evm::Error::BadJumpDestination {..}) 
 				| Err(evm::Error::BadInstruction {.. }) 
 				| Err(evm::Error::StackUnderflow {..})
 				| Err(evm::Error::OutOfStack {..}) => {
-				self.state.revert(backup);
+				self.state.revert_snapshot();
 			},
-			Ok(_) | Err(evm::Error::Internal) => substate.accrue(un_substate)
+			Ok(_) | Err(evm::Error::Internal) => {
+				self.state.clear_snapshot();
+				substate.accrue(un_substate)
+			}
 		}
 	}
 }

ethcore/src/state.rs

@@ -13,12 +13,11 @@ use pod_state::PodState;
 pub type ApplyResult = Result<Receipt, Error>;
 
 /// Representation of the entire state of all accounts in the system.
-#[derive(Clone)]
 pub struct State {
 	db: JournalDB,
 	root: H256,
 	cache: RefCell<HashMap<Address, Option<Account>>>,
-
+	snapshots: RefCell<Vec<HashMap<Address, Option<Option<Account>>>>>,
 	account_start_nonce: U256,
 }
 
@@ -36,6 +35,7 @@ impl State {
 			db: db,
 			root: root,
 			cache: RefCell::new(HashMap::new()),
+			snapshots: RefCell::new(Vec::new()),
 			account_start_nonce: account_start_nonce,
 		}
 	}
@@ -51,10 +51,62 @@ impl State {
 			db: db,
 			root: root,
 			cache: RefCell::new(HashMap::new()),
+			snapshots: RefCell::new(Vec::new()),
 			account_start_nonce: account_start_nonce,
 		}
 	}
 
+	/// Create a recoverable snaphot of this state
+	pub fn snapshot(&mut self) {
+		self.snapshots.borrow_mut().push(HashMap::new());
+	}
+
+	pub fn clear_snapshot(&mut self) {
+		// merge with previous snapshot
+		let last = self.snapshots.borrow_mut().pop();
+		if let Some(mut snapshot) = last {
+			if let Some(ref mut prev) = self.snapshots.borrow_mut().last_mut() {
+				for (k, v) in snapshot.drain() {
+					prev.entry(k).or_insert(v);
+				}
+			}
+		}
+	}
+
+	pub fn revert_snapshot(&mut self) {
+		if let Some(mut snapshot) = self.snapshots.borrow_mut().pop() {
+			for (k, v) in snapshot.drain() {
+				match v {
+					Some(v) => {
+						self.cache.borrow_mut().insert(k, v);
+					},
+					None => {
+						self.cache.borrow_mut().remove(&k);
+					}
+				}
+			}
+		}
+	}
+
+
+	fn insert_cache(&self, address: &Address, account: Option<Account>) {
+		if let Some(ref mut snapshot) = self.snapshots.borrow_mut().last_mut() {
+			if !snapshot.contains_key(&address) {
+				snapshot.insert(address.clone(), self.cache.borrow_mut().insert(address.clone(), account));
+				return;
+			}
+		}
+		self.cache.borrow_mut().insert(address.clone(), account);
+	}
+
+	fn note_cache(&self, address: &Address) {
+		if let Some(ref mut snapshot) = self.snapshots.borrow_mut().last_mut() {
+			if !snapshot.contains_key(&address) {
+				snapshot.insert(address.clone(), self.cache.borrow().get(address).cloned());
+			}
+		}
+	}
+
 	/// Destroy the current object and return root and database.
 	pub fn drop(self) -> (H256, JournalDB) {
 		(self.root, self.db)
@@ -68,12 +120,12 @@ impl State {
 	/// Create a new contract at address `contract`. If there is already an account at the address
 	/// it will have its code reset, ready for `init_code()`.
 	pub fn new_contract(&mut self, contract: &Address, balance: U256) {
-		self.cache.borrow_mut().insert(contract.clone(), Some(Account::new_contract(balance)));
+		self.insert_cache(&contract, Some(Account::new_contract(balance)));
 	}
 
 	/// Remove an existing account.
 	pub fn kill_account(&mut self, account: &Address) {
-		self.cache.borrow_mut().insert(account.clone(), None);
+		self.insert_cache(account, None);
 	}
 
 	/// Determine whether an account exists.
@@ -152,11 +204,6 @@ impl State {
 		Ok(receipt)
 	}
 
-	/// Reverts uncommited changed.
-	pub fn revert(&mut self, backup: State) {
-		self.cache = backup.cache;
-	}
-
 	/// Commit accounts to SecTrieDBMut. 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.
 	#[allow(match_ref_pats)]
@@ -186,6 +233,7 @@ impl State {
 
 	/// Commits our cached account changes into the trie.
 	pub fn commit(&mut self) {
+		assert!(self.snapshots.borrow().is_empty());
 		Self::commit_into(&mut self.db, &mut self.root, self.cache.borrow_mut().deref_mut());
 	}
 
@@ -193,6 +241,7 @@ impl State {
 	#[cfg(feature = "json-tests")]
 	/// Populate the state from `accounts`.
 	pub fn populate_from(&mut self, accounts: PodState) {
+		assert!(self.snapshots.borrow().is_empty());
 		for (add, acc) in accounts.drain().into_iter() {
 			self.cache.borrow_mut().insert(add, Some(Account::from_pod(acc)));
 		}
@@ -202,6 +251,7 @@ impl State {
 	#[cfg(feature = "json-tests")]
 	/// Populate a PodAccount map from this state.
 	pub fn to_pod(&self) -> PodState {
+		assert!(self.snapshots.borrow().is_empty());
 		// TODO: handle database rather than just the cache.
 		PodState::from(self.cache.borrow().iter().fold(BTreeMap::new(), |mut m, (add, opt)| {
 			if let Some(ref acc) = *opt {
@@ -214,9 +264,10 @@ impl State {
 	/// Pull account `a` in our cache from the trie DB and return it.
 	/// `require_code` requires that the code be cached, too.
 	fn get(&self, a: &Address, require_code: bool) -> Ref<Option<Account>> {
-		self.cache.borrow_mut().entry(a.clone()).or_insert_with(|| {
+		let have_key = self.cache.borrow().contains_key(a);
-			SecTrieDB::new(&self.db, &self.root).get(&a).map(|rlp| Account::from_rlp(rlp))
+		if !have_key {
-		});
+			self.insert_cache(a, SecTrieDB::new(&self.db, &self.root).get(&a).map(|rlp| Account::from_rlp(rlp)))
+		}
 		if require_code {
 			if let Some(ref mut account) = self.cache.borrow_mut().get_mut(a).unwrap().as_mut() {
 				account.cache_code(&self.db);
@@ -233,8 +284,12 @@ impl State {
 	/// Pull account `a` in our cache from the trie DB. `require_code` requires that the code be cached, too.
 	/// If it doesn't exist, make account equal the evaluation of `default`.
 	fn require_or_from<F: FnOnce() -> Account, G: FnOnce(&mut Account)>(&self, a: &Address, require_code: bool, default: F, not_default: G) -> RefMut<Account> {
-		self.cache.borrow_mut().entry(a.clone()).or_insert_with(||
+		let have_key = self.cache.borrow().contains_key(a);
-			SecTrieDB::new(&self.db, &self.root).get(&a).map(|rlp| Account::from_rlp(rlp)));
+		if !have_key {
+			self.insert_cache(a, SecTrieDB::new(&self.db, &self.root).get(&a).map(|rlp| Account::from_rlp(rlp)))
+		} else {
+			self.note_cache(a);
+		}
 		let preexists = self.cache.borrow().get(a).unwrap().is_none();
 		if preexists {
 			self.cache.borrow_mut().insert(a.clone(), Some(default()));

ethcore/src/tests/helpers.rs

@@ -48,17 +48,21 @@ impl Drop for RandomTempPath {
 
 #[cfg(test)]
 pub struct GuardedTempResult<T> {
-	result: T,
+	result: Option<T>,
 	_temp: RandomTempPath
 }
 
 impl<T> GuardedTempResult<T> {
     pub fn reference(&self) -> &T {
-        &self.result
+        self.result.as_ref().unwrap()
     }
 
     pub fn reference_mut(&mut self) -> &mut T {
-    	&mut self.result
+    	self.result.as_mut().unwrap()
+    }
+
+	pub fn take(&mut self) -> T {
+		self.result.take().unwrap()
 	}
 }
 
@@ -150,7 +154,7 @@ pub fn generate_dummy_client(block_number: u32) -> GuardedTempResult<Arc<Client>
 
 	GuardedTempResult::<Arc<Client>> {
 		_temp: dir,
-		result: client
+		result: Some(client)
 	}
 }
 
@@ -168,7 +172,7 @@ pub fn get_test_client_with_blocks(blocks: Vec<Bytes>) -> GuardedTempResult<Arc<
 
 	GuardedTempResult::<Arc<Client>> {
 		_temp: dir,
-		result: client
+		result: Some(client)
 	}
 }
 
@@ -181,7 +185,7 @@ pub fn generate_dummy_blockchain(block_number: u32) -> GuardedTempResult<BlockCh
 
 	GuardedTempResult::<BlockChain> {
 		_temp: temp,
-		result: bc
+		result: Some(bc)
 	}
 }
 
@@ -194,7 +198,7 @@ pub fn generate_dummy_blockchain_with_extra(block_number: u32) -> GuardedTempRes
 
 	GuardedTempResult::<BlockChain> {
 		_temp: temp,
-		result: bc
+		result: Some(bc)
 	}
 }
 
@@ -204,7 +208,7 @@ pub fn generate_dummy_empty_blockchain() -> GuardedTempResult<BlockChain> {
 
 	GuardedTempResult::<BlockChain> {
 		_temp: temp,
-		result: bc
+		result: Some(bc)
 	}
 }
 
@@ -214,7 +218,7 @@ pub fn get_temp_journal_db() -> GuardedTempResult<JournalDB> {
 	let journal_db = JournalDB::new(db);
 	GuardedTempResult {
 		_temp: temp,
-		result: journal_db
+		result: Some(journal_db)
 	}
 }
 
@@ -223,7 +227,7 @@ pub fn get_temp_state() -> GuardedTempResult<State> {
 	let journal_db = get_temp_journal_db_in(temp.as_path());
 	GuardedTempResult {
 	    _temp: temp,
-		result: State::new(journal_db, U256::from(0u8))
+		result: Some(State::new(journal_db, U256::from(0u8)))
 	}
 }
 

util/src/journaldb.rs

@@ -8,7 +8,6 @@ use rocksdb::{DB, Writable};
 #[cfg(test)]
 use std::env;
 
-#[derive(Clone)]
 /// Implementation of the HashDB trait for a disk-backed database with a memory overlay
 /// and latent-removal semantics.
 ///
@@ -53,8 +52,6 @@ impl JournalDB {
 		Self::new(DB::open_default(dir.to_str().unwrap()).unwrap())
 	}
 
-	/// Get a clone of the overlay db portion of this.
-	pub fn to_overlaydb(&self) -> OverlayDB { self.forward.clone() }
 
 	/// Commit all recent insert operations and historical removals from the old era
 	/// to the backing database.
@@ -119,10 +116,6 @@ impl JournalDB {
 
 		self.forward.commit()
 	}
-
-	/// Revert all operations on this object (i.e. `insert()`s and `removes()`s) since the
-	/// last `commit()`.
-	pub fn revert(&mut self) { self.forward.revert(); self.removes.clear(); }
 }
 
 impl HashDB for JournalDB {

util/src/overlaydb.rs

@@ -12,7 +12,6 @@ use std::env;
 use std::collections::HashMap;
 use rocksdb::{DB, Writable, IteratorMode};
 
-#[derive(Clone)]
 /// Implementation of the HashDB trait for a disk-backed database with a memory overlay.
 ///
 /// The operations `insert()` and `remove()` take place on the memory overlay; batches of