Engine and Spec are now thread safe

src/bin/client.rs

@@ -11,15 +11,16 @@ use util::network::{NetworkService};
 use ethcore::client::Client;
 use ethcore::sync::EthSync;
 use ethcore::ethereum;
+use ethcore::ethereum::ethash::Ethash;
 
 fn main() {
 	::env_logger::init().ok();
 	let mut service = NetworkService::start().unwrap();
 	//TODO: replace with proper genesis and chain params.
-	let frontier = ethereum::new_frontier();
+	let engine = Ethash::new_arc(ethereum::new_frontier());
 	let mut dir = env::temp_dir();
 	dir.push(H32::random().hex());
-	let client = Arc::new(Client::new(&frontier.genesis_block(), &dir));
+	let client = Arc::new(Client::new(engine, &dir));
 	EthSync::register(&mut service, client);
 	loop {
 		let mut cmd = String::new();

src/blockchain.rs

@@ -1,6 +1,5 @@
 //! Fast access to blockchain data.
 
-use std::sync::*;
 use util::*;
 use rocksdb::{DB, WriteBatch, Writable};
 use header::*;

src/builtin.rs

@@ -12,6 +12,11 @@ pub struct Builtin {
 	pub execute: Box<Fn(&[u8], &mut [u8])>,
 }
 
+// Rust does not mark closurer that do not capture as Sync
+// We promise that all builtins are thread safe since they only operate on given input.
+unsafe impl Sync for Builtin {}
+unsafe impl Send for Builtin {}
+
 impl fmt::Debug for Builtin {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		write!(f, "<Builtin>")

src/client.rs

@@ -1,9 +1,9 @@
-use std::sync::Arc;
 use util::*;
 use blockchain::BlockChain;
 use views::BlockView;
 use error::ImportError;
 use header::BlockNumber;
+use engine::Engine;
 
 /// General block status
 pub enum BlockStatus {
@@ -95,13 +95,15 @@ pub trait BlockChainClient : Sync {
 /// Blockchain database client backed by a persistent database. Owns and manages a blockchain and a block queue.
 pub struct Client {
 	chain: Arc<BlockChain>,
+	_engine: Arc<Engine>,
 }
 
 impl Client {
-	pub fn new(genesis: &[u8], path: &Path) -> Client {
-		let chain = Arc::new(BlockChain::new(genesis, path));
+	pub fn new(engine: Arc<Engine>, path: &Path) -> Client {
+		let chain = Arc::new(BlockChain::new(&engine.spec().genesis_block(), path));
 		Client {
 			chain: chain.clone(),
+			_engine: engine.clone(),
 		}
 	}
 }

src/engine.rs

@@ -4,7 +4,7 @@ use spec::Spec;
 
 /// A consensus mechanism for the chain. Generally either proof-of-work or proof-of-stake-based.
 /// Provides hooks into each of the major parts of block import.
-pub trait Engine {
+pub trait Engine : Sync + Send {
 	/// The name of this engine.
 	fn name(&self) -> &str;
 	/// The version of this engine. Should be of the form 

src/ethereum/ethash.rs

@@ -13,6 +13,10 @@ impl Ethash {
 	pub fn new_boxed(spec: Spec) -> Box<Engine> {
 		Box::new(Ethash{spec: spec})
 	}
+
+	pub fn new_arc(spec: Spec) -> Arc<Engine> {
+		Arc::new(Ethash{spec: spec})
+	}
 }
 
 impl Engine for Ethash {

src/ethereum/mod.rs

@@ -52,7 +52,7 @@ mod tests {
 	fn morden() {
 		let morden = new_morden();
 
-		assert_eq!(*morden.state_root(), H256::from_str("f3f4696bbf3b3b07775128eb7a3763279a394e382130f27c21e70233e04946a9").unwrap());
+		assert_eq!(morden.state_root(), H256::from_str("f3f4696bbf3b3b07775128eb7a3763279a394e382130f27c21e70233e04946a9").unwrap());
 		let genesis = morden.genesis_block();
 		assert_eq!(BlockView::new(&genesis).header_view().sha3(), H256::from_str("0cd786a2425d16f152c658316c423e6ce1181e15c3295826d7c9904cba9ce303").unwrap());
 
@@ -63,7 +63,7 @@ mod tests {
 	fn frontier() {
 		let frontier = new_frontier();
 
-		assert_eq!(*frontier.state_root(), H256::from_str("d7f8974fb5ac78d9ac099b9ad5018bedc2ce0a72dad1827a1709da30580f0544").unwrap());
+		assert_eq!(frontier.state_root(), H256::from_str("d7f8974fb5ac78d9ac099b9ad5018bedc2ce0a72dad1827a1709da30580f0544").unwrap());
 		let genesis = frontier.genesis_block();
 		assert_eq!(BlockView::new(&genesis).header_view().sha3(), H256::from_str("d4e56740f876aef8c010b86a40d5f56745a118d0906a34e69aec8c0db1cb8fa3").unwrap());
 

src/spec.rs

@@ -40,6 +40,27 @@ fn json_to_rlp_map(json: &Json) -> HashMap<String, Bytes> {
 	})
 }
 
+//TODO: add code and data
+#[derive(Debug)]
+/// Genesis account data. Does no thave a DB overlay cache
+pub struct GenesisAccount {
+	// Balance of the account.
+	balance: U256,
+	// Nonce of the account.
+	nonce: U256,
+}
+
+impl GenesisAccount {
+	pub fn rlp(&self) -> Bytes {
+		let mut stream = RlpStream::new_list(4);
+		stream.append(&self.nonce);
+		stream.append(&self.balance);
+		stream.append(&SHA3_NULL_RLP);
+		stream.append(&SHA3_EMPTY);
+		stream.out()
+	}
+}
+
 /// Parameters for a block chain; includes both those intrinsic to the design of the
 /// chain and those to be interpreted by the active chain engine.
 #[derive(Debug)]
@@ -62,12 +83,12 @@ pub struct Spec {
 	pub gas_used: U256,
 	pub timestamp: u64,
 	pub extra_data: Bytes,
-	pub genesis_state: HashMap<Address, Account>,
+	pub genesis_state: HashMap<Address, GenesisAccount>,
 	pub seal_fields: usize,
 	pub seal_rlp: Bytes,
 
 	// May be prepopulated if we know this in advance.
-	state_root_memo: RefCell<Option<H256>>,
+	state_root_memo: RwLock<Option<H256>>,
 }
 
 impl Spec {
@@ -82,11 +103,11 @@ impl Spec {
 	}
 
 	/// Return the state root for the genesis state, memoising accordingly.
-	pub fn state_root(&self) -> Ref<H256> {
-		if self.state_root_memo.borrow().is_none() {
-			*self.state_root_memo.borrow_mut() = Some(sec_trie_root(self.genesis_state.iter().map(|(k, v)| (k.to_vec(), v.rlp())).collect()));
+	pub fn state_root(&self) -> H256 {
+		if self.state_root_memo.read().unwrap().is_none() {
+			*self.state_root_memo.write().unwrap() = Some(sec_trie_root(self.genesis_state.iter().map(|(k, v)| (k.to_vec(), v.rlp())).collect()));
 		}
-		Ref::map(self.state_root_memo.borrow(), |x|x.as_ref().unwrap())
+		self.state_root_memo.read().unwrap().as_ref().unwrap().clone()
 	}
 
 	pub fn genesis_header(&self) -> Header {
@@ -113,7 +134,7 @@ impl Spec {
 				let r = Rlp::new(&seal);
 				(0..self.seal_fields).map(|i| r.at(i).as_raw().to_vec()).collect()
 			},
-			hash: RefCell::new(None)
+			hash: RefCell::new(None),
 		}
 	}
 
@@ -149,7 +170,7 @@ impl Spec {
 //				let nonce = if let Some(&Json::String(ref n)) = acc.find("nonce") {U256::from_dec_str(n).unwrap_or(U256::from(0))} else {U256::from(0)};
 				// TODO: handle code & data if they exist.
 				if balance.is_some() || nonce.is_some() {
-					state.insert(addr, Account::new_basic(balance.unwrap_or(U256::from(0)), nonce.unwrap_or(U256::from(0))));
+					state.insert(addr, GenesisAccount { balance: balance.unwrap_or(U256::from(0)), nonce: nonce.unwrap_or(U256::from(0)) });
 				}
 			}
 		}
@@ -186,7 +207,7 @@ impl Spec {
 			genesis_state: state,
 			seal_fields: seal_fields,
 			seal_rlp: seal_rlp,
-			state_root_memo: RefCell::new(genesis.find("stateRoot").and_then(|_| genesis["stateRoot"].as_string()).map(|s| H256::from_str(&s[2..]).unwrap())),
+			state_root_memo: RwLock::new(genesis.find("stateRoot").and_then(|_| genesis["stateRoot"].as_string()).map(|s| H256::from_str(&s[2..]).unwrap())),
 		}
 	}
 
@@ -228,7 +249,7 @@ mod tests {
 	fn test_chain() {
 		let test_spec = Spec::new_test();
 
-		assert_eq!(*test_spec.state_root(), H256::from_str("f3f4696bbf3b3b07775128eb7a3763279a394e382130f27c21e70233e04946a9").unwrap());
+		assert_eq!(test_spec.state_root(), H256::from_str("f3f4696bbf3b3b07775128eb7a3763279a394e382130f27c21e70233e04946a9").unwrap());
 		let genesis = test_spec.genesis_block();
 		assert_eq!(BlockView::new(&genesis).header_view().sha3(), H256::from_str("0cd786a2425d16f152c658316c423e6ce1181e15c3295826d7c9904cba9ce303").unwrap());
 

src/sync/mod.rs

@@ -13,12 +13,13 @@
 /// use ethcore::client::Client;
 /// use ethcore::sync::EthSync;
 /// use ethcore::ethereum;
+/// use ethcore::ethereum::ethash::Ethash;
 ///
 /// fn main() {
 /// 	let mut service = NetworkService::start().unwrap();
-///		let frontier = ethereum::new_frontier();
+/// 	let engine = Ethash::new_arc(ethereum::new_frontier());
 /// 	let dir = env::temp_dir();
-/// 	let client = Arc::new(Client::new(&frontier.genesis_block(), &dir));
+/// 	let client = Arc::new(Client::new(engine, &dir));
 /// 	EthSync::register(&mut service, client);
 /// }
 /// ```