minimal state backend trait

make state module public

ethcore/src/block.rs

@@ -91,7 +91,7 @@ pub struct ExecutedBlock {
 	uncles: Vec<Header>,
 	receipts: Vec<Receipt>,
 	transactions_set: HashSet<H256>,
-	state: State,
+	state: State<StateDB>,
 	traces: Option<Vec<Vec<FlatTrace>>>,
 }
 
@@ -106,7 +106,7 @@ pub struct BlockRefMut<'a> {
 	/// Transaction receipts.
 	pub receipts: &'a [Receipt],
 	/// State.
-	pub state: &'a mut State,
+	pub state: &'a mut State<StateDB>,
 	/// Traces.
 	pub traces: &'a Option<Vec<Vec<FlatTrace>>>,
 }
@@ -122,14 +122,14 @@ pub struct BlockRef<'a> {
 	/// Transaction receipts.
 	pub receipts: &'a [Receipt],
 	/// State.
-	pub state: &'a State,
+	pub state: &'a State<StateDB>,
 	/// Traces.
 	pub traces: &'a Option<Vec<Vec<FlatTrace>>>,
 }
 
 impl ExecutedBlock {
 	/// Create a new block from the given `state`.
-	fn new(state: State, tracing: bool) -> ExecutedBlock {
+	fn new(state: State<StateDB>, tracing: bool) -> ExecutedBlock {
 		ExecutedBlock {
 			header: Default::default(),
 			transactions: Default::default(),
@@ -184,7 +184,7 @@ pub trait IsBlock {
 	fn header(&self) -> &Header { &self.block().header }
 
 	/// Get the final state associated with this object's block.
-	fn state(&self) -> &State { &self.block().state }
+	fn state(&self) -> &State<StateDB> { &self.block().state }
 
 	/// Get all information on transactions in this block.
 	fn transactions(&self) -> &[SignedTransaction] { &self.block().transactions }
@@ -228,7 +228,7 @@ pub struct ClosedBlock {
 	block: ExecutedBlock,
 	uncle_bytes: Bytes,
 	last_hashes: Arc<LastHashes>,
-	unclosed_state: State,
+	unclosed_state: State<StateDB>,
 }
 
 /// Just like `ClosedBlock` except that we can't reopen it and it's faster.

ethcore/src/client/client.rs

@@ -656,7 +656,7 @@ impl Client {
 	/// This will not fail if given BlockId::Latest.
 	/// Otherwise, this can fail (but may not) if the DB prunes state or the block
 	/// is unknown.
-	pub fn state_at(&self, id: BlockId) -> Option<State> {
+	pub fn state_at(&self, id: BlockId) -> Option<State<StateDB>> {
 		// fast path for latest state.
 		match id.clone() {
 			BlockId::Pending => return self.miner.pending_state().or_else(|| Some(self.state())),
@@ -686,7 +686,7 @@ impl Client {
 	///
 	/// This will not fail if given BlockId::Latest.
 	/// Otherwise, this can fail (but may not) if the DB prunes state.
-	pub fn state_at_beginning(&self, id: BlockId) -> Option<State> {
+	pub fn state_at_beginning(&self, id: BlockId) -> Option<State<StateDB>> {
 		// fast path for latest state.
 		match id {
 			BlockId::Pending => self.state_at(BlockId::Latest),
@@ -698,7 +698,7 @@ impl Client {
 	}
 
 	/// Get a copy of the best block's state.
-	pub fn state(&self) -> State {
+	pub fn state(&self) -> State<StateDB> {
 		let header = self.best_block_header();
 		State::from_existing(
 			self.state_db.lock().boxed_clone_canon(&header.hash()),

ethcore/src/executive.rs

@@ -17,7 +17,7 @@
 //! Transaction Execution environment.
 use util::*;
 use action_params::{ActionParams, ActionValue};
-use state::{State, Substate, CleanupMode};
+use state::{Backend as StateBackend, State, Substate, CleanupMode};
 use engines::Engine;
 use types::executed::CallType;
 use env_info::EnvInfo;
@@ -56,17 +56,17 @@ pub struct TransactOptions {
 }
 
 /// Transaction executor.
-pub struct Executive<'a> {
+pub struct Executive<'a, B: 'a + StateBackend> {
-	state: &'a mut State,
+	state: &'a mut State<B>,
 	info: &'a EnvInfo,
 	engine: &'a Engine,
 	vm_factory: &'a Factory,
 	depth: usize,
 }
 
-impl<'a> Executive<'a> {
+impl<'a, B: 'a + StateBackend> Executive<'a, B> {
 	/// Basic constructor.
-	pub fn new(state: &'a mut State, info: &'a EnvInfo, engine: &'a Engine, vm_factory: &'a Factory) -> Self {
+	pub fn new(state: &'a mut State<B>, info: &'a EnvInfo, engine: &'a Engine, vm_factory: &'a Factory) -> Self {
 		Executive {
 			state: state,
 			info: info,
@@ -77,7 +77,7 @@ impl<'a> Executive<'a> {
 	}
 
 	/// Populates executive from parent properties. Increments executive depth.
-	pub fn from_parent(state: &'a mut State, info: &'a EnvInfo, engine: &'a Engine, vm_factory: &'a Factory, parent_depth: usize) -> Self {
+	pub fn from_parent(state: &'a mut State<B>, info: &'a EnvInfo, engine: &'a Engine, vm_factory: &'a Factory, parent_depth: usize) -> Self {
 		Executive {
 			state: state,
 			info: info,
@@ -95,7 +95,7 @@ impl<'a> Executive<'a> {
 		output: OutputPolicy<'any, 'any>,
 		tracer: &'any mut T,
 		vm_tracer: &'any mut V
-	) -> Externalities<'any, T, V> where T: Tracer, V: VMTracer {
+	) -> Externalities<'any, T, V, B> where T: Tracer, V: VMTracer {
 		Externalities::new(self.state, self.info, self.engine, self.vm_factory, self.depth, origin_info, substate, output, tracer, vm_tracer)
 	}
 

ethcore/src/externalities.rs

@@ -17,7 +17,7 @@
 //! Transaction Execution environment.
 use util::*;
 use action_params::{ActionParams, ActionValue};
-use state::{State, Substate};
+use state::{Backend as StateBackend, State, Substate};
 use engines::Engine;
 use env_info::EnvInfo;
 use executive::*;
@@ -57,8 +57,10 @@ impl OriginInfo {
 }
 
 /// Implementation of evm Externalities.
-pub struct Externalities<'a, T, V> where T: 'a + Tracer, V: 'a + VMTracer {
+pub struct Externalities<'a, T: 'a, V: 'a, B: 'a>
-	state: &'a mut State,
+	where T: Tracer, V:  VMTracer, B: StateBackend
+{
+	state: &'a mut State<B>,
 	env_info: &'a EnvInfo,
 	engine: &'a Engine,
 	vm_factory: &'a Factory,
@@ -71,10 +73,12 @@ pub struct Externalities<'a, T, V> where T: 'a + Tracer, V: 'a + VMTracer {
 	vm_tracer: &'a mut V,
 }
 
-impl<'a, T, V> Externalities<'a, T, V> where T: 'a + Tracer, V: 'a + VMTracer {
+impl<'a, T: 'a, V: 'a, B: 'a> Externalities<'a, T, V, B>
-	#[cfg_attr(feature="dev", allow(too_many_arguments))]
+	where T: Tracer, V: VMTracer, B: StateBackend
+{
 	/// Basic `Externalities` constructor.
-	pub fn new(state: &'a mut State,
+	#[cfg_attr(feature="dev", allow(too_many_arguments))]
+	pub fn new(state: &'a mut State<B>,
 		env_info: &'a EnvInfo,
 		engine: &'a Engine,
 		vm_factory: &'a Factory,
@@ -101,7 +105,9 @@ impl<'a, T, V> Externalities<'a, T, V> where T: 'a + Tracer, V: 'a + VMTracer {
 	}
 }
 
-impl<'a, T, V> Ext for Externalities<'a, T, V> where T: 'a + Tracer, V: 'a + VMTracer {
+impl<'a, T: 'a, V: 'a, B: 'a> Ext for Externalities<'a, T, V, B>
+	where T: Tracer, V: VMTracer, B: StateBackend
+{
 	fn storage_at(&self, key: &H256) -> H256 {
 		self.state.storage_at(&self.origin_info.address, key)
 	}
@@ -346,7 +352,7 @@ mod tests {
 	}
 
 	struct TestSetup {
-		state: GuardedTempResult<State>,
+		state: GuardedTempResult<State<::state_db::StateDB>>,
 		engine: Arc<Engine>,
 		sub_state: Substate,
 		env_info: EnvInfo

ethcore/src/lib.rs

@@ -139,6 +139,7 @@ pub mod snapshot;
 pub mod action_params;
 pub mod db;
 pub mod verification;
+pub mod state;
 #[macro_use] pub mod evm;
 
 mod cache_manager;
@@ -146,7 +147,6 @@ mod blooms;
 mod basic_types;
 mod env_info;
 mod pod_account;
-mod state;
 mod state_db;
 mod account_db;
 mod builtin;

ethcore/src/miner/miner.rs

@@ -307,7 +307,7 @@ impl Miner {
 	}
 
 	/// Get `Some` `clone()` of the current pending block's state or `None` if we're not sealing.
-	pub fn pending_state(&self) -> Option<State> {
+	pub fn pending_state(&self) -> Option<State<::state_db::StateDB>> {
 		self.sealing_work.lock().queue.peek_last_ref().map(|b| b.block().fields().state.clone())
 	}
 

ethcore/src/spec/spec.rs

@@ -24,7 +24,7 @@ use executive::Executive;
 use trace::{NoopTracer, NoopVMTracer};
 use action_params::{ActionValue, ActionParams};
 use types::executed::CallType;
-use state::{State, Substate};
+use state::{Backend, State, Substate};
 use env_info::EnvInfo;
 use pod_state::*;
 use account_db::*;

ethcore/src/state/backend.rs

@@ -24,10 +24,10 @@
 use std::sync::Arc;
 
 use state::Account;
-use util::{Address, HashDB, H256};
+use util::{Address, AsHashDB, HashDB, H256};
 
 /// State backend. See module docs for more details.
-pub trait Backend {
+pub trait Backend: Send {
 	/// Treat the backend as a read-only hashdb.
 	fn as_hashdb(&self) -> &HashDB;
 
@@ -42,7 +42,7 @@ pub trait Backend {
 	/// hash collisions.
 	fn cache_code(&self, hash: H256, code: Arc<Vec<u8>>);
 
-	/// Get basic copy of the cached account. Does not include storage.
+	/// Get basic copy of the cached account. Not required to include storage.
 	/// Returns 'None' if cache is disabled or if the account is not cached.
 	fn get_cached_account(&self, addr: &Address) -> Option<Option<Account>>;
 
@@ -55,4 +55,39 @@ pub trait Backend {
 
 	/// Get cached code based on hash.
 	fn get_cached_code(&self, hash: &H256) -> Option<Arc<Vec<u8>>>;
+
+	/// Note that an account with the given address is non-null.
+	fn note_non_null_account(&self, address: &Address);
+
+	/// Check whether an account is known to be empty. Returns true if known to be
+	/// empty, false otherwise.
+	fn is_known_null(&self, address: &Address) -> bool;
+}
+
+/// A raw backend which simply wraps a hashdb and does no caching.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct NoCache<T>(T);
+
+impl<T> NoCache<T> {
+	/// Create a new `NoCache` backend.
+	pub fn new(inner: T) -> Self { NoCache(inner) }
+
+	/// Consume the backend, yielding the inner database.
+	pub fn into_inner(self) -> T { self.0 }
+}
+
+impl<T: AsHashDB + Send> Backend for NoCache<T> {
+	fn as_hashdb(&self) -> &HashDB { self.0.as_hashdb() }
+	fn as_hashdb_mut(&mut self) -> &mut HashDB { self.0.as_hashdb_mut() }
+	fn add_to_account_cache(&mut self, _addr: Address, _data: Option<Account>, _modified: bool) {}
+	fn cache_code(&self, _hash: H256, _code: Arc<Vec<u8>>) {}
+	fn get_cached_account(&self, _addr: &Address) -> Option<Option<Account>> { None }
+	fn get_cached<F, U>(&self, _a: &Address, _f: F) -> Option<U>
+		where F: FnOnce(Option<&mut Account>) -> U
+	{
+		None
+	}
+	fn get_cached_code(&self, _hash: &H256) -> Option<Arc<Vec<u8>>> { None }
+	fn note_non_null_account(&self, _address: &Address) {}
+	fn is_known_null(&self, _address: &Address) -> bool { false }
 }

ethcore/src/state/mod.rs

@@ -14,6 +14,11 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
+//! A mutable state representation suitable to execute transactions.
+//! Generic over a `Backend`. Deals with `Account`s.
+//! Unconfirmed sub-states are managed with `checkpoint`s which may be canonicalized
+//! or rolled back.
+
 use std::cell::{RefCell, RefMut};
 use std::collections::hash_map::Entry;
 
@@ -40,6 +45,7 @@ mod substate;
 pub mod backend;
 
 pub use self::account::Account;
+pub use self::backend::Backend;
 pub use self::substate::Substate;
 
 /// Used to return information about an `State::apply` operation.
@@ -188,8 +194,8 @@ impl AccountEntry {
 /// checkpoint can be discateded with `discard_checkpoint`. All of the orignal
 /// backed-up values are moved into a parent checkpoint (if any).
 ///
-pub struct State {
+pub struct State<B> {
-	db: StateDB,
+	db: B,
 	root: H256,
 	cache: RefCell<HashMap<Address, AccountEntry>>,
 	// The original account is preserved in
@@ -205,20 +211,24 @@ enum RequireCache {
 	Code,
 }
 
+/// Mode of dealing with null accounts.
 #[derive(PartialEq)]
 pub enum CleanupMode<'a> {
+	/// Create accounts which would be null.
 	ForceCreate,
+	/// Don't delete null accounts upon touching, but also don't create them.
 	NoEmpty,
+	/// Add encountered null accounts to the provided kill-set, to be deleted later.
 	KillEmpty(&'a mut HashSet<Address>),
 }
 
 const SEC_TRIE_DB_UNWRAP_STR: &'static str = "A state can only be created with valid root. Creating a SecTrieDB with a valid root will not fail. \
 			 Therefore creating a SecTrieDB with this state's root will not fail.";
 
-impl State {
+impl<B: Backend> State<B> {
 	/// Creates new state with empty state root
 	#[cfg(test)]
-	pub fn new(mut db: StateDB, account_start_nonce: U256, factories: Factories) -> State {
+	pub fn new(mut db: B, account_start_nonce: U256, factories: Factories) -> State<B> {
 		let mut root = H256::new();
 		{
 			// init trie and reset root too null
@@ -236,7 +246,7 @@ impl State {
 	}
 
 	/// Creates new state with existing state root
-	pub fn from_existing(db: StateDB, root: H256, account_start_nonce: U256, factories: Factories) -> Result<State, TrieError> {
+	pub fn from_existing(db: B, root: H256, account_start_nonce: U256, factories: Factories) -> Result<State<B>, TrieError> {
 		if !db.as_hashdb().contains(&root) {
 			return Err(TrieError::InvalidStateRoot(root));
 		}
@@ -330,7 +340,7 @@ impl State {
 	}
 
 	/// Destroy the current object and return root and database.
-	pub fn drop(mut self) -> (H256, StateDB) {
+	pub fn drop(mut self) -> (H256, B) {
 		self.propagate_to_global_cache();
 		(self.root, self.db)
 	}
@@ -422,8 +432,8 @@ impl State {
 			}
 		}
 
-		// check bloom before any requests to trie
+		// check if the account could exist before any requests to trie
-		if !self.db.check_non_null_bloom(address) { return H256::zero() }
+		if self.db.is_known_null(address) { return H256::zero() }
 
 		// account is not found in the global cache, get from the DB and insert into local
 		let db = self.factories.trie.readonly(self.db.as_hashdb(), &self.root).expect(SEC_TRIE_DB_UNWRAP_STR);
@@ -445,6 +455,7 @@ impl State {
 			|a| a.as_ref().map_or(None, |a| a.code().clone()))
 	}
 
+	/// Get an account's code hash.
 	pub fn code_hash(&self, a: &Address) -> H256 {
 		self.ensure_cached(a, RequireCache::None, true,
 			|a| a.as_ref().map_or(SHA3_EMPTY, |a| a.code_hash()))
@@ -538,7 +549,7 @@ impl State {
 	#[cfg_attr(feature="dev", allow(needless_borrow))]
 	fn commit_into(
 		factories: &Factories,
-		db: &mut StateDB,
+		db: &mut B,
 		root: &mut H256,
 		accounts: &mut HashMap<Address, AccountEntry>
 	) -> Result<(), Error> {
@@ -632,7 +643,7 @@ impl State {
 
 	/// Returns a `StateDiff` describing the difference from `orig` to `self`.
 	/// Consumes self.
-	pub fn diff_from(&self, orig: State) -> StateDiff {
+	pub fn diff_from<X: Backend>(&self, orig: State<X>) -> StateDiff {
 		let pod_state_post = self.to_pod();
 		let mut state_pre = orig;
 		state_pre.query_pod(&pod_state_post);
@@ -640,7 +651,7 @@ impl State {
 	}
 
 	// load required account data from the databases.
-	fn update_account_cache(require: RequireCache, account: &mut Account, state_db: &StateDB, db: &HashDB) {
+	fn update_account_cache(require: RequireCache, account: &mut Account, state_db: &B, db: &HashDB) {
 		match (account.is_cached(), require) {
 			(true, _) | (false, RequireCache::None) => {}
 			(false, require) => {
@@ -670,7 +681,7 @@ impl State {
 	/// Check caches for required data
 	/// First searches for account in the local, then the shared cache.
 	/// Populates local cache if nothing found.
-	fn ensure_cached<F, U>(&self, a: &Address, require: RequireCache, check_bloom: bool, f: F) -> U
+	fn ensure_cached<F, U>(&self, a: &Address, require: RequireCache, check_null: bool, f: F) -> U
 		where F: Fn(Option<&Account>) -> U {
 		// check local cache first
 		if let Some(ref mut maybe_acc) = self.cache.borrow_mut().get_mut(a) {
@@ -692,8 +703,8 @@ impl State {
 		match result {
 			Some(r) => r,
 			None => {
-				// first check bloom if it is not in database for sure
+				// first check if it is not in database for sure
-				if check_bloom && !self.db.check_non_null_bloom(a) { return f(None); }
+				if check_null && self.db.is_known_null(a) { return f(None); }
 
 				// not found in the global cache, get from the DB and insert into local
 				let db = self.factories.trie.readonly(self.db.as_hashdb(), &self.root).expect(SEC_TRIE_DB_UNWRAP_STR);
@@ -727,7 +738,7 @@ impl State {
 			match self.db.get_cached_account(a) {
 				Some(acc) => self.insert_cache(a, AccountEntry::new_clean_cached(acc)),
 				None => {
-					let maybe_acc = if self.db.check_non_null_bloom(a) {
+					let maybe_acc = if !self.db.is_known_null(a) {
 						let db = self.factories.trie.readonly(self.db.as_hashdb(), &self.root).expect(SEC_TRIE_DB_UNWRAP_STR);
 						match db.get_with(a, Account::from_rlp) {
 							Ok(acc) => AccountEntry::new_clean(acc),
@@ -769,7 +780,7 @@ impl State {
 }
 
 // LES state proof implementations.
-impl State {
+impl<B: Backend> State<B> {
 	/// Prove an account's existence or nonexistence in the state trie.
 	/// Returns a merkle proof of the account's trie node with all nodes before `from_level`
 	/// omitted or an encountered trie error.
@@ -815,14 +826,16 @@ impl State {
 	}
 }
 
-impl fmt::Debug for State {
+impl<B> fmt::Debug for State<B> {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		write!(f, "{:?}", self.cache.borrow())
 	}
 }
 
-impl Clone for State {
+// TODO: cloning for `State` shouldn't be possible in general; Remove this and use
-	fn clone(&self) -> State {
+// checkpoints where possible.
+impl Clone for State<StateDB> {
+	fn clone(&self) -> State<StateDB> {
 		let cache = {
 			let mut cache: HashMap<Address, AccountEntry> = HashMap::new();
 			for (key, val) in self.cache.borrow().iter() {

ethcore/src/state_db.rs

@@ -21,7 +21,7 @@ use util::journaldb::JournalDB;
 use util::kvdb::KeyValueDB;
 use util::hash::{H256};
 use util::hashdb::HashDB;
-use state::Account;
+use state::{self, Account};
 use header::BlockNumber;
 use util::{Arc, Address, DBTransaction, UtilError, Mutex, Hashable};
 use bloom_journal::{Bloom, BloomJournal};
@@ -166,18 +166,6 @@ impl StateDB {
 		bloom
 	}
 
-	pub fn check_non_null_bloom(&self, address: &Address) -> bool {
-		trace!(target: "account_bloom", "Check account bloom: {:?}", address);
-		let bloom = self.account_bloom.lock();
-		bloom.check(&*address.sha3())
-	}
-
-	pub fn note_non_null_account(&self, address: &Address) {
-		trace!(target: "account_bloom", "Note account bloom: {:?}", address);
-		let mut bloom = self.account_bloom.lock();
-		bloom.set(&*address.sha3());
-	}
-
 	pub fn commit_bloom(batch: &mut DBTransaction, journal: BloomJournal) -> Result<(), UtilError> {
 		assert!(journal.hash_functions <= 255);
 		batch.put(COL_ACCOUNT_BLOOM, ACCOUNT_BLOOM_HASHCOUNT_KEY, &[journal.hash_functions as u8]);
@@ -306,12 +294,10 @@ impl StateDB {
 		}
 	}
 
-	/// Returns an interface to HashDB.
 	pub fn as_hashdb(&self) -> &HashDB {
 		self.db.as_hashdb()
 	}
 
-	/// Returns an interface to mutable HashDB.
 	pub fn as_hashdb_mut(&mut self) -> &mut HashDB {
 		self.db.as_hashdb_mut()
 	}
@@ -366,56 +352,6 @@ impl StateDB {
 		&*self.db
 	}
 
-	/// Add a local cache entry.
-	/// The entry will be propagated to the global cache in `sync_cache`.
-	/// `modified` indicates that the entry was changed since being read from disk or global cache.
-	/// `data` can be set to an existing (`Some`), or non-existing account (`None`).
-	pub fn add_to_account_cache(&mut self, addr: Address, data: Option<Account>, modified: bool) {
-		self.local_cache.push(CacheQueueItem {
-			address: addr,
-			account: data,
-			modified: modified,
-		})
-	}
-
-	/// Add a global code cache entry. This doesn't need to worry about canonicality because
-	/// it simply maps hashes to raw code and will always be correct in the absence of
-	/// hash collisions.
-	pub fn cache_code(&self, hash: H256, code: Arc<Vec<u8>>) {
-		let mut cache = self.code_cache.lock();
-
-		cache.insert(hash, code);
-	}
-
-	/// Get basic copy of the cached account. Does not include storage.
-	/// Returns 'None' if cache is disabled or if the account is not cached.
-	pub fn get_cached_account(&self, addr: &Address) -> Option<Option<Account>> {
-		let mut cache = self.account_cache.lock();
-		if !Self::is_allowed(addr, &self.parent_hash, &cache.modifications) {
-			return None;
-		}
-		cache.accounts.get_mut(addr).map(|a| a.as_ref().map(|a| a.clone_basic()))
-	}
-
-	/// Get cached code based on hash.
-	#[cfg_attr(feature="dev", allow(map_clone))]
-	pub fn get_cached_code(&self, hash: &H256) -> Option<Arc<Vec<u8>>> {
-		let mut cache = self.code_cache.lock();
-
-		cache.get_mut(hash).map(|code| code.clone())
-	}
-
-	/// Get value from a cached account.
-	/// Returns 'None' if cache is disabled or if the account is not cached.
-	pub fn get_cached<F, U>(&self, a: &Address, f: F) -> Option<U>
-		where F: FnOnce(Option<&mut Account>) -> U {
-		let mut cache = self.account_cache.lock();
-		if !Self::is_allowed(a, &self.parent_hash, &cache.modifications) {
-			return None;
-		}
-		cache.accounts.get_mut(a).map(|c| f(c.as_mut()))
-	}
-
 	/// Query how much memory is set aside for the accounts cache (in bytes).
 	pub fn cache_size(&self) -> usize {
 		self.cache_size
@@ -456,11 +392,71 @@ impl StateDB {
 	}
 }
 
+impl state::Backend for StateDB {
+	fn as_hashdb(&self) -> &HashDB {
+		self.db.as_hashdb()
+	}
+
+	fn as_hashdb_mut(&mut self) -> &mut HashDB {
+		self.db.as_hashdb_mut()
+	}
+
+	fn add_to_account_cache(&mut self, addr: Address, data: Option<Account>, modified: bool) {
+		self.local_cache.push(CacheQueueItem {
+			address: addr,
+			account: data,
+			modified: modified,
+		})
+	}
+
+	fn cache_code(&self, hash: H256, code: Arc<Vec<u8>>) {
+		let mut cache = self.code_cache.lock();
+
+		cache.insert(hash, code);
+	}
+
+	fn get_cached_account(&self, addr: &Address) -> Option<Option<Account>> {
+		let mut cache = self.account_cache.lock();
+		if !Self::is_allowed(addr, &self.parent_hash, &cache.modifications) {
+			return None;
+		}
+		cache.accounts.get_mut(addr).map(|a| a.as_ref().map(|a| a.clone_basic()))
+	}
+
+	#[cfg_attr(feature="dev", allow(map_clone))]
+	fn get_cached_code(&self, hash: &H256) -> Option<Arc<Vec<u8>>> {
+		let mut cache = self.code_cache.lock();
+
+		cache.get_mut(hash).map(|code| code.clone())
+	}
+
+	fn get_cached<F, U>(&self, a: &Address, f: F) -> Option<U>
+		where F: FnOnce(Option<&mut Account>) -> U {
+		let mut cache = self.account_cache.lock();
+		if !Self::is_allowed(a, &self.parent_hash, &cache.modifications) {
+			return None;
+		}
+		cache.accounts.get_mut(a).map(|c| f(c.as_mut()))
+	}
+
+	fn note_non_null_account(&self, address: &Address) {
+		trace!(target: "account_bloom", "Note account bloom: {:?}", address);
+		let mut bloom = self.account_bloom.lock();
+		bloom.set(&*address.sha3());
+	}
+
+	fn is_known_null(&self, address: &Address) -> bool {
+		trace!(target: "account_bloom", "Check account bloom: {:?}", address);
+		let bloom = self.account_bloom.lock();
+		!bloom.check(&*address.sha3())
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use util::{U256, H256, FixedHash, Address, DBTransaction};
 	use tests::helpers::*;
-	use state::Account;
+	use state::{Account, Backend};
 	use util::log::init_log;
 
 	#[test]

ethcore/src/tests/helpers.rs

@@ -349,7 +349,7 @@ pub fn get_temp_state_db() -> GuardedTempResult<StateDB> {
 	}
 }
 
-pub fn get_temp_state() -> GuardedTempResult<State> {
+pub fn get_temp_state() -> GuardedTempResult<State<::state_db::StateDB>> {
 	let temp = RandomTempPath::new();
 	let journal_db = get_temp_state_db_in(temp.as_path());
 
@@ -365,7 +365,7 @@ pub fn get_temp_state_db_in(path: &Path) -> StateDB {
 	StateDB::new(journal_db, 5 * 1024 * 1024)
 }
 
-pub fn get_temp_state_in(path: &Path) -> State {
+pub fn get_temp_state_in(path: &Path) -> State<::state_db::StateDB> {
 	let journal_db = get_temp_state_db_in(path);
 	State::new(journal_db, U256::from(0), Default::default())
 }