Merge pull request #4485 from ethcore/lightrpc

Preparation for Light client RPC

Cargo.lock

@@ -601,6 +601,7 @@ dependencies = [
  "ethcore-devtools 1.6.0",
  "ethcore-io 1.6.0",
  "ethcore-ipc 1.6.0",
+ "ethcore-light 1.6.0",
  "ethcore-util 1.6.0",
  "ethcrypto 0.1.0",
  "ethjson 0.1.0",

ethcore/light/src/client/header_chain.rs

@@ -32,9 +32,10 @@ use cht;
 
 use ethcore::block_status::BlockStatus;
 use ethcore::error::BlockError;
+use ethcore::encoded;
+use ethcore::header::Header;
 use ethcore::ids::BlockId;
-use ethcore::views::HeaderView;
+use util::{H256, U256, HeapSizeOf, Mutex, RwLock};
-use util::{Bytes, H256, U256, HeapSizeOf, Mutex, RwLock};
 
 use smallvec::SmallVec;
 
@@ -77,9 +78,9 @@ impl HeapSizeOf for Entry {
 
 /// Header chain. See module docs for more details.
 pub struct HeaderChain {
-	genesis_header: Bytes, // special-case the genesis.
+	genesis_header: encoded::Header, // special-case the genesis.
 	candidates: RwLock<BTreeMap<u64, Entry>>,
-	headers: RwLock<HashMap<H256, Bytes>>,
+	headers: RwLock<HashMap<H256, encoded::Header>>,
 	best_block: RwLock<BlockDescriptor>,
 	cht_roots: Mutex<Vec<H256>>,
 }
@@ -87,10 +88,12 @@ pub struct HeaderChain {
 impl HeaderChain {
 	/// Create a new header chain given this genesis block.
 	pub fn new(genesis: &[u8]) -> Self {
+		use ethcore::views::HeaderView;
+
 		let g_view = HeaderView::new(genesis);
 
 		HeaderChain {
-			genesis_header: genesis.to_owned(),
+			genesis_header: encoded::Header::new(genesis.to_owned()),
 			best_block: RwLock::new(BlockDescriptor {
 				hash: g_view.hash(),
 				number: 0,
@@ -104,14 +107,11 @@ impl HeaderChain {
 
 	/// Insert a pre-verified header.
 	///
-	/// This blindly trusts that the data given to it is
+	/// This blindly trusts that the data given to it is sensible.
-	/// a) valid RLP encoding of a header and
+	pub fn insert(&self, header: Header) -> Result<(), BlockError> {
-	/// b) has sensible data contained within it.
+		let hash = header.hash();
-	pub fn insert(&self, header: Bytes) -> Result<(), BlockError> {
+		let number = header.number();
-		let view = HeaderView::new(&header);
+		let parent_hash = *header.parent_hash();
-		let hash = view.hash();
-		let number = view.number();
-		let parent_hash = view.parent_hash();
 
 		// hold candidates the whole time to guard import order.
 		let mut candidates = self.candidates.write();
@@ -119,8 +119,7 @@ impl HeaderChain {
 		// find parent details.
 		let parent_td =
 			if number == 1 {
-				let g_view = HeaderView::new(&self.genesis_header);
+				self.genesis_header.difficulty()
-				g_view.difficulty()
 			} else {
 				candidates.get(&(number - 1))
 					.and_then(|entry| entry.candidates.iter().find(|c| c.hash == parent_hash))
@@ -128,7 +127,7 @@ impl HeaderChain {
 					.ok_or_else(|| BlockError::UnknownParent(parent_hash))?
 			};
 
-		let total_difficulty = parent_td + view.difficulty();
+		let total_difficulty = parent_td + *header.difficulty();
 
 		// insert headers and candidates entries.
 		candidates.entry(number).or_insert_with(|| Entry { candidates: SmallVec::new(), canonical_hash: hash })
@@ -138,7 +137,8 @@ impl HeaderChain {
 				total_difficulty: total_difficulty,
 		});
 
-		self.headers.write().insert(hash, header.clone());
+		let raw = ::rlp::encode(&header).to_vec();
+		self.headers.write().insert(hash, encoded::Header::new(raw));
 
 		// reorganize ancestors so canonical entries are first in their
 		// respective candidates vectors.
@@ -211,24 +211,36 @@ impl HeaderChain {
 
 	/// Get a block header. In the case of query by number, only canonical blocks
 	/// will be returned.
-	pub fn get_header(&self, id: BlockId) -> Option<Bytes> {
+	pub fn block_header(&self, id: BlockId) -> Option<encoded::Header> {
 		match id {
 			BlockId::Earliest | BlockId::Number(0) => Some(self.genesis_header.clone()),
-			BlockId::Latest if self.headers.read().is_empty() => Some(self.genesis_header.clone()),
+			BlockId::Hash(hash) => self.headers.read().get(&hash).cloned(),
-			BlockId::Hash(hash) => self.headers.read().get(&hash).map(|x| x.to_vec()),
 			BlockId::Number(num) => {
 				if self.best_block.read().number < num { return None }
 
 				self.candidates.read().get(&num).map(|entry| entry.canonical_hash)
-					.and_then(|hash| self.headers.read().get(&hash).map(|x| x.to_vec()))
+					.and_then(|hash| self.headers.read().get(&hash).cloned())
 			}
 			BlockId::Latest | BlockId::Pending => {
-				let hash = self.best_block.read().hash;
+				let hash = {
-				self.headers.read().get(&hash).map(|x| x.to_vec())
+					let best = self.best_block.read();
+					if best.number == 0 {
+						return Some(self.genesis_header.clone())
+					}
+
+					best.hash
+				};
+
+				self.headers.read().get(&hash).cloned()
 			}
 		}
 	}
 
+	/// Get the best block's header.
+	pub fn best_header(&self) -> encoded::Header {
+		self.block_header(BlockId::Latest).expect("Header for best block always stored; qed")
+	}
+
 	/// Get the nth CHT root, if it's been computed.
 	///
 	/// CHT root 0 is from block `1..2048`.
@@ -305,15 +317,15 @@ mod tests {
 			header.set_number(i);
 			header.set_timestamp(rolling_timestamp);
 			header.set_difficulty(*genesis_header.difficulty() * i.into());
-
-			chain.insert(::rlp::encode(&header).to_vec()).unwrap();
-
 			parent_hash = header.hash();
+
+			chain.insert(header).unwrap();
+
 			rolling_timestamp += 10;
 		}
 
-		assert!(chain.get_header(BlockId::Number(10)).is_none());
+		assert!(chain.block_header(BlockId::Number(10)).is_none());
-		assert!(chain.get_header(BlockId::Number(9000)).is_some());
+		assert!(chain.block_header(BlockId::Number(9000)).is_some());
 		assert!(chain.cht_root(2).is_some());
 		assert!(chain.cht_root(3).is_none());
 	}
@@ -333,10 +345,10 @@ mod tests {
 			header.set_number(i);
 			header.set_timestamp(rolling_timestamp);
 			header.set_difficulty(*genesis_header.difficulty() * i.into());
-
-			chain.insert(::rlp::encode(&header).to_vec()).unwrap();
-
 			parent_hash = header.hash();
+
+			chain.insert(header).unwrap();
+
 			rolling_timestamp += 10;
 		}
 
@@ -349,10 +361,10 @@ mod tests {
 				header.set_number(i);
 				header.set_timestamp(rolling_timestamp);
 				header.set_difficulty(*genesis_header.difficulty() * i.into());
-
-				chain.insert(::rlp::encode(&header).to_vec()).unwrap();
-
 				parent_hash = header.hash();
+
+				chain.insert(header).unwrap();
+
 				rolling_timestamp += 10;
 			}
 		}
@@ -370,10 +382,10 @@ mod tests {
 				header.set_number(i);
 				header.set_timestamp(rolling_timestamp);
 				header.set_difficulty(*genesis_header.difficulty() * (i * i).into());
-
-				chain.insert(::rlp::encode(&header).to_vec()).unwrap();
-
 				parent_hash = header.hash();
+
+				chain.insert(header).unwrap();
+
 				rolling_timestamp += 11;
 			}
 		}
@@ -382,11 +394,23 @@ mod tests {
 		assert_eq!(num, 12);
 
 		while num > 0 {
-			let header: Header = ::rlp::decode(&chain.get_header(BlockId::Number(num)).unwrap());
+			let header = chain.block_header(BlockId::Number(num)).unwrap();
 			assert_eq!(header.hash(), canon_hash);
 
-			canon_hash = *header.parent_hash();
+			canon_hash = header.parent_hash();
 			num -= 1;
 		}
 	}
+
+	#[test]
+	fn earliest_is_latest() {
+		let spec = Spec::new_test();
+		let genesis_header = spec.genesis_header();
+
+		let chain = HeaderChain::new(&::rlp::encode(&genesis_header));
+
+		assert!(chain.block_header(BlockId::Earliest).is_some());
+		assert!(chain.block_header(BlockId::Latest).is_some());
+		assert!(chain.block_header(BlockId::Pending).is_some());
+	}
 }

ethcore/light/src/client/mod.rs

@@ -21,7 +21,6 @@ use ethcore::block_status::BlockStatus;
 use ethcore::client::ClientReport;
 use ethcore::ids::BlockId;
 use ethcore::header::Header;
-use ethcore::views::HeaderView;
 use ethcore::verification::queue::{self, HeaderQueue};
 use ethcore::transaction::{PendingTransaction, Condition as TransactionCondition};
 use ethcore::blockchain_info::BlockChainInfo;
@@ -35,7 +34,6 @@ use util::{Bytes, Mutex, RwLock};
 
 use provider::Provider;
 use request;
-use time;
 
 use self::header_chain::HeaderChain;
 
@@ -109,12 +107,12 @@ impl Client {
 
 	/// Fetch a vector of all pending transactions.
 	pub fn ready_transactions(&self) -> Vec<PendingTransaction> {
-		let best_num = self.chain.best_block().number;
+		let best = self.chain.best_header();
 		self.tx_pool.lock()
 			.values()
 			.filter(|t| match t.condition {
-				Some(TransactionCondition::Number(ref x)) => x <= &best_num,
+				Some(TransactionCondition::Number(x)) => x <= best.number(),
-				Some(TransactionCondition::Timestamp(ref x)) => *x <= time::get_time().sec as u64,
+				Some(TransactionCondition::Timestamp(x)) => x <= best.timestamp(),
 				None => true,
 			})
 			.cloned()
@@ -131,17 +129,19 @@ impl Client {
 
 	/// Get the chain info.
 	pub fn chain_info(&self) -> BlockChainInfo {
-		let best_block = self.chain.best_block();
+		let best_hdr = self.chain.best_header();
+		let best_td = self.chain.best_block().total_difficulty;
+
 		let first_block = self.chain.first_block();
 		let genesis_hash = self.chain.genesis_hash();
 
 		BlockChainInfo {
-			total_difficulty: best_block.total_difficulty,
+			total_difficulty: best_td,
-			pending_total_difficulty: best_block.total_difficulty + self.queue.total_difficulty(),
+			pending_total_difficulty: best_td + self.queue.total_difficulty(),
 			genesis_hash: genesis_hash,
-			best_block_hash: best_block.hash,
+			best_block_hash: best_hdr.hash(),
-			best_block_number: best_block.number,
+			best_block_number: best_hdr.number(),
-			best_block_timestamp: HeaderView::new(&self.chain.get_header(BlockId::Latest).expect("Latest hash is always in the chain")).timestamp(),
+			best_block_timestamp: best_hdr.timestamp(),
 			ancient_block_hash: if first_block.is_some() { Some(genesis_hash) } else { None },
 			ancient_block_number: if first_block.is_some() { Some(0) } else { None },
 			first_block_hash: first_block.as_ref().map(|first| first.hash),
@@ -155,8 +155,8 @@ impl Client {
 	}
 
 	/// Get a block header by Id.
-	pub fn get_header(&self, id: BlockId) -> Option<Bytes> {
+	pub fn block_header(&self, id: BlockId) -> Option<encoded::Header> {
-		self.chain.get_header(id)
+		self.chain.block_header(id)
 	}
 
 	/// Flush the header queue.
@@ -180,7 +180,7 @@ impl Client {
 		for verified_header in self.queue.drain(MAX) {
 			let (num, hash) = (verified_header.number(), verified_header.hash());
 
-			match self.chain.insert(::rlp::encode(&verified_header).to_vec()) {
+			match self.chain.insert(verified_header) {
 				Ok(()) => {
 					good.push(hash);
 					self.report.write().blocks_imported += 1;
@@ -252,7 +252,7 @@ impl Provider for Client {
 	}
 
 	fn block_header(&self, id: BlockId) -> Option<encoded::Header> {
-		self.chain.get_header(id).map(encoded::Header::new)
+		Client::block_header(self, id)
 	}
 
 	fn block_body(&self, _id: BlockId) -> Option<encoded::Body> {

ethcore/light/src/on_demand/mod.rs

@@ -25,52 +25,17 @@ use ethcore::encoded;
 use ethcore::receipt::Receipt;
 
 use futures::{Async, Poll, Future};
-use futures::sync::oneshot;
+use futures::sync::oneshot::{self, Sender, Receiver};
 use network::PeerId;
+use rlp::{RlpStream, Stream};
+use util::{Bytes, RwLock, U256};
+use util::sha3::{SHA3_NULL_RLP, SHA3_EMPTY_LIST_RLP};
 
 use net::{Handler, Status, Capabilities, Announcement, EventContext, BasicContext, ReqId};
-use util::{Bytes, RwLock, U256};
 use types::les_request::{self as les_request, Request as LesRequest};
 
 pub mod request;
 
-/// Errors which can occur while trying to fulfill a request.
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum Error {
-	/// Request was canceled.
-	Canceled,
-	/// No suitable peers available to serve the request.
-	NoPeersAvailable,
-	/// Invalid request.
-	InvalidRequest,
-	/// Request timed out.
-	TimedOut,
-}
-
-impl From<oneshot::Canceled> for Error {
-	fn from(_: oneshot::Canceled) -> Self {
-		Error::Canceled
-	}
-}
-
-/// Future which awaits a response to an on-demand request.
-pub struct Response<T>(oneshot::Receiver<Result<T, Error>>);
-
-impl<T> Future for Response<T> {
-	type Item = T;
-	type Error = Error;
-
-	fn poll(&mut self) -> Poll<T, Error> {
-		match self.0.poll().map_err(Into::into) {
-			Ok(Async::Ready(val)) => val.map(Async::Ready),
-			Ok(Async::NotReady) => Ok(Async::NotReady),
-			Err(e) => Err(e),
-		}
-	}
-}
-
-type Sender<T> = oneshot::Sender<Result<T, Error>>;
-
 // relevant peer info.
 struct Peer {
 	status: Status,
@@ -84,6 +49,7 @@ enum Pending {
 	Block(request::Body, Sender<encoded::Block>),
 	BlockReceipts(request::BlockReceipts, Sender<Vec<Receipt>>),
 	Account(request::Account, Sender<BasicAccount>),
+	Code(request::Code, Sender<Bytes>),
 }
 
 /// On demand request service. See module docs for more details.
@@ -92,6 +58,7 @@ enum Pending {
 pub struct OnDemand {
 	peers: RwLock<HashMap<PeerId, Peer>>,
 	pending_requests: RwLock<HashMap<ReqId, Pending>>,
+	orphaned_requests: RwLock<Vec<Pending>>,
 }
 
 impl Default for OnDemand {
@@ -99,6 +66,7 @@ impl Default for OnDemand {
 		OnDemand {
 			peers: RwLock::new(HashMap::new()),
 			pending_requests: RwLock::new(HashMap::new()),
+			orphaned_requests: RwLock::new(Vec::new()),
 		}
 	}
 }
@@ -106,32 +74,27 @@ impl Default for OnDemand {
 impl OnDemand {
 	/// Request a header by block number and CHT root hash.
 	/// Returns the header and the total difficulty.
-	pub fn header_by_number(&self, ctx: &BasicContext, req: request::HeaderByNumber) -> Response<(encoded::Header, U256)> {
+	pub fn header_by_number(&self, ctx: &BasicContext, req: request::HeaderByNumber) -> Receiver<(encoded::Header, U256)> {
 		let (sender, receiver) = oneshot::channel();
 		self.dispatch_header_by_number(ctx, req, sender);
-		Response(receiver)
+		receiver
 	}
 
 	// dispatch the request, completing the request if no peers available.
 	fn dispatch_header_by_number(&self, ctx: &BasicContext, req: request::HeaderByNumber, sender: Sender<(encoded::Header, U256)>) {
-		let num = req.num;
+		let num = req.num();
-		let cht_num = match ::cht::block_to_cht_number(req.num) {
+		let cht_num = req.cht_num();
-			Some(cht_num) => cht_num,
-			None => {
-				warn!(target: "on_demand", "Attempted to dispatch invalid header proof: req.num == 0");
-				sender.complete(Err(Error::InvalidRequest));
-				return;
-			}
-		};
 
 		let les_req = LesRequest::HeaderProofs(les_request::HeaderProofs {
 			requests: vec![les_request::HeaderProof {
 				cht_number: cht_num,
-				block_number: req.num,
+				block_number: num,
 				from_level: 0,
 			}],
 		});
 
+		let pending = Pending::HeaderByNumber(req, sender);
+
 		// we're looking for a peer with serveHeaders who's far enough along in the
 		// chain.
 		for (id, peer) in self.peers.read().iter() {
@@ -141,7 +104,7 @@ impl OnDemand {
 						trace!(target: "on_demand", "Assigning request to peer {}", id);
 						self.pending_requests.write().insert(
 							req_id,
-							Pending::HeaderByNumber(req, sender)
+							pending,
 						);
 						return
 					},
@@ -151,18 +114,17 @@ impl OnDemand {
 			}
 		}
 
-		// TODO: retrying
 		trace!(target: "on_demand", "No suitable peer for request");
-		sender.complete(Err(Error::NoPeersAvailable));
+		self.orphaned_requests.write().push(pending)
 	}
 
 	/// Request a header by hash. This is less accurate than by-number because we don't know
 	/// where in the chain this header lies, and therefore can't find a peer who is supposed to have
 	/// it as easily.
-	pub fn header_by_hash(&self, ctx: &BasicContext, req: request::HeaderByHash) -> Response<encoded::Header> {
+	pub fn header_by_hash(&self, ctx: &BasicContext, req: request::HeaderByHash) -> Receiver<encoded::Header> {
 		let (sender, receiver) = oneshot::channel();
 		self.dispatch_header_by_hash(ctx, req, sender);
-		Response(receiver)
+		receiver
 	}
 
 	fn dispatch_header_by_hash(&self, ctx: &BasicContext, req: request::HeaderByHash, sender: Sender<encoded::Header>) {
@@ -181,16 +143,17 @@ impl OnDemand {
 			.collect::<Vec<_>>();
 
 		let mut rng = ::rand::thread_rng();
-
 		::rand::Rng::shuffle(&mut rng, &mut potential_peers);
 
+		let pending = Pending::HeaderByHash(req, sender);
+
 		for id in potential_peers {
 			match ctx.request_from(id, les_req.clone()) {
 				Ok(req_id) => {
 					trace!(target: "on_demand", "Assigning request to peer {}", id);
 					self.pending_requests.write().insert(
 						req_id,
-						Pending::HeaderByHash(req, sender),
+						pending,
 					);
 					return
 				}
@@ -199,18 +162,28 @@ impl OnDemand {
 			}
 		}
 
-		// TODO: retrying
 		trace!(target: "on_demand", "No suitable peer for request");
-		sender.complete(Err(Error::NoPeersAvailable));
+		self.orphaned_requests.write().push(pending)
 	}
 
 	/// Request a block, given its header. Block bodies are requestable by hash only,
 	/// and the header is required anyway to verify and complete the block body
 	/// -- this just doesn't obscure the network query.
-	pub fn block(&self, ctx: &BasicContext, req: request::Body) -> Response<encoded::Block> {
+	pub fn block(&self, ctx: &BasicContext, req: request::Body) -> Receiver<encoded::Block> {
 		let (sender, receiver) = oneshot::channel();
+
+		// fast path for empty body.
+		if req.header.transactions_root() == SHA3_NULL_RLP && req.header.uncles_hash() == SHA3_EMPTY_LIST_RLP {
+			let mut stream = RlpStream::new_list(3);
+			stream.append_raw(&req.header.into_inner(), 1);
+			stream.begin_list(0);
+			stream.begin_list(0);
+
+			sender.complete(encoded::Block::new(stream.out()))
+		} else {
 			self.dispatch_block(ctx, req, sender);
-		Response(receiver)
+		}
+		receiver
 	}
 
 	fn dispatch_block(&self, ctx: &BasicContext, req: request::Body, sender: Sender<encoded::Block>) {
@@ -218,6 +191,7 @@ impl OnDemand {
 		let les_req = LesRequest::Bodies(les_request::Bodies {
 			block_hashes: vec![req.hash],
 		});
+		let pending = Pending::Block(req, sender);
 
 		// we're looking for a peer with serveChainSince(num)
 		for (id, peer) in self.peers.read().iter() {
@@ -227,7 +201,7 @@ impl OnDemand {
 						trace!(target: "on_demand", "Assigning request to peer {}", id);
 						self.pending_requests.write().insert(
 							req_id,
-							Pending::Block(req, sender)
+							pending,
 						);
 						return
 					}
@@ -237,17 +211,23 @@ impl OnDemand {
 			}
 		}
 
-		// TODO: retrying
 		trace!(target: "on_demand", "No suitable peer for request");
-		sender.complete(Err(Error::NoPeersAvailable));
+		self.orphaned_requests.write().push(pending)
 	}
 
 	/// Request the receipts for a block. The header serves two purposes:
 	/// provide the block hash to fetch receipts for, and for verification of the receipts root.
-	pub fn block_receipts(&self, ctx: &BasicContext, req: request::BlockReceipts) -> Response<Vec<Receipt>> {
+	pub fn block_receipts(&self, ctx: &BasicContext, req: request::BlockReceipts) -> Receiver<Vec<Receipt>> {
 		let (sender, receiver) = oneshot::channel();
+
+		// fast path for empty receipts.
+		if req.0.receipts_root() == SHA3_NULL_RLP {
+			sender.complete(Vec::new())
+		} else {
 			self.dispatch_block_receipts(ctx, req, sender);
-		Response(receiver)
+		}
+
+		receiver
 	}
 
 	fn dispatch_block_receipts(&self, ctx: &BasicContext, req: request::BlockReceipts, sender: Sender<Vec<Receipt>>) {
@@ -255,6 +235,7 @@ impl OnDemand {
 		let les_req = LesRequest::Receipts(les_request::Receipts {
 			block_hashes: vec![req.0.hash()],
 		});
+		let pending = Pending::BlockReceipts(req, sender);
 
 		// we're looking for a peer with serveChainSince(num)
 		for (id, peer) in self.peers.read().iter() {
@@ -264,7 +245,7 @@ impl OnDemand {
 						trace!(target: "on_demand", "Assigning request to peer {}", id);
 						self.pending_requests.write().insert(
 							req_id,
-							Pending::BlockReceipts(req, sender)
+							pending,
 						);
 						return
 					}
@@ -274,17 +255,16 @@ impl OnDemand {
 			}
 		}
 
-		// TODO: retrying
 		trace!(target: "on_demand", "No suitable peer for request");
-		sender.complete(Err(Error::NoPeersAvailable));
+		self.orphaned_requests.write().push(pending)
 	}
 
 	/// Request an account by address and block header -- which gives a hash to query and a state root
 	/// to verify against.
-	pub fn account(&self, ctx: &BasicContext, req: request::Account) -> Response<BasicAccount> {
+	pub fn account(&self, ctx: &BasicContext, req: request::Account) -> Receiver<BasicAccount> {
 		let (sender, receiver) = oneshot::channel();
 		self.dispatch_account(ctx, req, sender);
-		Response(receiver)
+		receiver
 	}
 
 	fn dispatch_account(&self, ctx: &BasicContext, req: request::Account, sender: Sender<BasicAccount>) {
@@ -297,6 +277,7 @@ impl OnDemand {
 				from_level: 0,
 			}],
 		});
+		let pending = Pending::Account(req, sender);
 
 		// we're looking for a peer with serveStateSince(num)
 		for (id, peer) in self.peers.read().iter() {
@@ -306,7 +287,7 @@ impl OnDemand {
 						trace!(target: "on_demand", "Assigning request to peer {}", id);
 						self.pending_requests.write().insert(
 							req_id,
-							Pending::Account(req, sender)
+							pending,
 						);
 						return
 					}
@@ -316,38 +297,125 @@ impl OnDemand {
 			}
 		}
 
-		// TODO: retrying
 		trace!(target: "on_demand", "No suitable peer for request");
-		sender.complete(Err(Error::NoPeersAvailable));
+		self.orphaned_requests.write().push(pending)
+	}
+
+	/// Request code by address, known code hash, and block header.
+	pub fn code(&self, ctx: &BasicContext, req: request::Code) -> Receiver<Bytes> {
+		let (sender, receiver) = oneshot::channel();
+
+		// fast path for no code.
+		if req.code_hash == ::util::sha3::SHA3_EMPTY {
+			sender.complete(Vec::new())
+		} else {
+			self.dispatch_code(ctx, req, sender);
+		}
+
+		receiver
+	}
+
+	fn dispatch_code(&self, ctx: &BasicContext, req: request::Code, sender: Sender<Bytes>) {
+		let num = req.block_id.1;
+		let les_req = LesRequest::Codes(les_request::ContractCodes {
+			code_requests: vec![les_request::ContractCode {
+				block_hash: req.block_id.0,
+				account_key: ::util::Hashable::sha3(&req.address),
+			}]
+		});
+		let pending = Pending::Code(req, sender);
+
+		// we're looking for a peer with serveStateSince(num)
+		for (id, peer) in self.peers.read().iter() {
+			if peer.capabilities.serve_state_since.as_ref().map_or(false, |x| *x >= num) {
+				match ctx.request_from(*id, les_req.clone()) {
+					Ok(req_id) => {
+						trace!(target: "on_demand", "Assigning request to peer {}", id);
+						self.pending_requests.write().insert(
+							req_id,
+							pending
+						);
+						return
+					}
+					Err(e) =>
+						trace!(target: "on_demand", "Failed to make request of peer {}: {:?}", id, e),
+				}
+			}
+		}
+
+		trace!(target: "on_demand", "No suitable peer for request");
+		self.orphaned_requests.write().push(pending)
+	}
+
+	// dispatch orphaned requests, and discard those for which the corresponding
+	// receiver has been dropped.
+	fn dispatch_orphaned(&self, ctx: &BasicContext) {
+		// wrapper future for calling `poll_cancel` on our `Senders` to preserve
+		// the invariant that it's always within a task.
+		struct CheckHangup<'a, T: 'a>(&'a mut Sender<T>);
+
+		impl<'a, T: 'a> Future for CheckHangup<'a, T> {
+			type Item = bool;
+			type Error = ();
+
+			fn poll(&mut self) -> Poll<bool, ()> {
+				Ok(Async::Ready(match self.0.poll_cancel() {
+					Ok(Async::NotReady) => false, // hasn't hung up.
+					_ => true, // has hung up.
+				}))
+			}
+		}
+
+		// check whether a sender's hung up (using `wait` to preserve the task invariant)
+		// returns true if has hung up, false otherwise.
+		fn check_hangup<T>(send: &mut Sender<T>) -> bool {
+			CheckHangup(send).wait().expect("CheckHangup always returns ok; qed")
+		}
+
+		if self.orphaned_requests.read().is_empty() { return }
+
+		let to_dispatch = ::std::mem::replace(&mut *self.orphaned_requests.write(), Vec::new());
+
+		for orphaned in to_dispatch {
+			match orphaned {
+				Pending::HeaderByNumber(req, mut sender) =>
+					if !check_hangup(&mut sender) { self.dispatch_header_by_number(ctx, req, sender) },
+				Pending::HeaderByHash(req, mut sender) =>
+					if !check_hangup(&mut sender) {	self.dispatch_header_by_hash(ctx, req, sender) },
+				Pending::Block(req, mut sender) =>
+					if !check_hangup(&mut sender) { self.dispatch_block(ctx, req, sender) },
+				Pending::BlockReceipts(req, mut sender) =>
+					if !check_hangup(&mut sender) { self.dispatch_block_receipts(ctx, req, sender) },
+				Pending::Account(req, mut sender) =>
+					if !check_hangup(&mut sender) { self.dispatch_account(ctx, req, sender) },
+				Pending::Code(req, mut sender) =>
+					if !check_hangup(&mut sender) { self.dispatch_code(ctx, req, sender) },
+			}
+		}
 	}
 }
 
 impl Handler for OnDemand {
 	fn on_connect(&self, ctx: &EventContext, status: &Status, capabilities: &Capabilities) {
 		self.peers.write().insert(ctx.peer(), Peer { status: status.clone(), capabilities: capabilities.clone() });
+		self.dispatch_orphaned(ctx.as_basic());
 	}
 
 	fn on_disconnect(&self, ctx: &EventContext, unfulfilled: &[ReqId]) {
 		self.peers.write().remove(&ctx.peer());
 		let ctx = ctx.as_basic();
 
+		{
+			let mut orphaned = self.orphaned_requests.write();
 			for unfulfilled in unfulfilled {
 				if let Some(pending) = self.pending_requests.write().remove(unfulfilled) {
 					trace!(target: "on_demand", "Attempting to reassign dropped request");
-				match pending {
+					orphaned.push(pending);
-					Pending::HeaderByNumber(req, sender)
-						=> self.dispatch_header_by_number(ctx, req, sender),
-					Pending::HeaderByHash(req, sender)
-						=> self.dispatch_header_by_hash(ctx, req, sender),
-					Pending::Block(req, sender)
-						=> self.dispatch_block(ctx, req, sender),
-					Pending::BlockReceipts(req, sender)
-						=> self.dispatch_block_receipts(ctx, req, sender),
-					Pending::Account(req, sender)
-						=> self.dispatch_account(ctx, req, sender),
 				}
 			}
 		}
+
+		self.dispatch_orphaned(ctx);
 	}
 
 	fn on_announcement(&self, ctx: &EventContext, announcement: &Announcement) {
@@ -356,6 +424,8 @@ impl Handler for OnDemand {
 			peer.status.update_from(&announcement);
 			peer.capabilities.update_from(&announcement);
 		}
+
+		self.dispatch_orphaned(ctx.as_basic());
 	}
 
 	fn on_header_proofs(&self, ctx: &EventContext, req_id: ReqId, proofs: &[(Bytes, Vec<Bytes>)]) {
@@ -370,7 +440,7 @@ impl Handler for OnDemand {
 				if let Some(&(ref header, ref proof)) = proofs.get(0) {
 					match req.check_response(header, proof) {
 						Ok(header) => {
-							sender.complete(Ok(header));
+							sender.complete(header);
 							return
 						}
 						Err(e) => {
@@ -398,7 +468,7 @@ impl Handler for OnDemand {
 				if let Some(ref header) = headers.get(0) {
 					match req.check_response(header) {
 						Ok(header) => {
-							sender.complete(Ok(header));
+							sender.complete(header);
 							return
 						}
 						Err(e) => {
@@ -426,7 +496,7 @@ impl Handler for OnDemand {
 				if let Some(ref block) = bodies.get(0) {
 					match req.check_response(block) {
 						Ok(block) => {
-							sender.complete(Ok(block));
+							sender.complete(block);
 							return
 						}
 						Err(e) => {
@@ -454,7 +524,7 @@ impl Handler for OnDemand {
 				if let Some(ref receipts) = receipts.get(0) {
 					match req.check_response(receipts) {
 						Ok(receipts) => {
-							sender.complete(Ok(receipts));
+							sender.complete(receipts);
 							return
 						}
 						Err(e) => {
@@ -482,7 +552,7 @@ impl Handler for OnDemand {
 				if let Some(ref proof) = proofs.get(0) {
 					match req.check_response(proof) {
 						Ok(proof) => {
-							sender.complete(Ok(proof));
+							sender.complete(proof);
 							return
 						}
 						Err(e) => {
@@ -497,6 +567,38 @@ impl Handler for OnDemand {
 			_ => panic!("Only account request fetches state proof; qed"),
 		}
 	}
+
+	fn on_code(&self, ctx: &EventContext, req_id: ReqId, codes: &[Bytes]) {
+		let peer = ctx.peer();
+		let req = match self.pending_requests.write().remove(&req_id) {
+			Some(req) => req,
+			None => return,
+		};
+
+		match req {
+			Pending::Code(req, sender) => {
+				if let Some(code) = codes.get(0) {
+					match req.check_response(code.as_slice()) {
+						Ok(()) => {
+							sender.complete(code.clone());
+							return
+						}
+						Err(e) => {
+							warn!("Error handling response for code request: {:?}", e);
+							ctx.disable_peer(peer);
+						}
+					}
+
+					self.dispatch_code(ctx.as_basic(), req, sender);
+				}
+			}
+			_ => panic!("Only code request fetches code; qed"),
+		}
+	}
+
+	fn tick(&self, ctx: &BasicContext) {
+		self.dispatch_orphaned(ctx)
+	}
 }
 
 #[cfg(test)]
@@ -505,7 +607,6 @@ mod tests {
 	use net::{Announcement, BasicContext, ReqId, Error as LesError};
 	use request::{Request as LesRequest, Kind as LesRequestKind};
 	use network::{PeerId, NodeId};
-	use futures::Future;
 	use util::H256;
 
 	struct FakeContext;
@@ -522,10 +623,14 @@ mod tests {
 	}
 
 	#[test]
-	fn no_peers() {
+	fn detects_hangup() {
 		let on_demand = OnDemand::default();
 		let result = on_demand.header_by_hash(&FakeContext, request::HeaderByHash(H256::default()));
 
-		assert_eq!(result.wait().unwrap_err(), Error::NoPeersAvailable);
+		assert!(on_demand.orphaned_requests.read().len() == 1);
+		drop(result);
+
+		on_demand.dispatch_orphaned(&FakeContext);
+		assert!(on_demand.orphaned_requests.read().is_empty());
 	}
 }

ethcore/light/src/on_demand/request.rs

@@ -37,7 +37,7 @@ pub enum Error {
 	BadProof,
 	/// Wrong header number.
 	WrongNumber(u64, u64),
-	/// Wrong header hash.
+	/// Wrong hash.
 	WrongHash(H256, H256),
 	/// Wrong trie root.
 	WrongTrieRoot(H256, H256),
@@ -59,12 +59,33 @@ impl From<Box<TrieError>> for Error {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct HeaderByNumber {
 	/// The header's number.
-	pub num: u64,
+	num: u64,
+	/// The cht number for the given block number.
+	cht_num: u64,
 	/// The root of the CHT containing this header.
-	pub cht_root: H256,
+	cht_root: H256,
 }
 
 impl HeaderByNumber {
+	/// Construct a new header-by-number request. Fails if the given number is 0.
+	/// Provide the expected CHT root to compare against.
+	pub fn new(num: u64, cht_root: H256) -> Option<Self> {
+		::cht::block_to_cht_number(num).map(|cht_num| HeaderByNumber {
+			num: num,
+			cht_num: cht_num,
+			cht_root: cht_root,
+		})
+	}
+
+	/// Access the requested block number.
+	pub fn num(&self) -> u64 { self.num }
+
+	/// Access the CHT number.
+	pub fn cht_num(&self) -> u64 { self.cht_num }
+
+	/// Access the expected CHT root.
+	pub fn cht_root(&self) -> H256 { self.cht_root }
+
 	/// Check a response with a header and cht proof.
 	pub fn check_response(&self, header: &[u8], proof: &[Bytes]) -> Result<(encoded::Header, U256), Error> {
 		let (expected_hash, td) = match ::cht::check_proof(proof, self.num, self.cht_root) {
@@ -106,6 +127,15 @@ pub struct Body {
 }
 
 impl Body {
+	/// Create a request for a block body from a given header.
+	pub fn new(header: encoded::Header) -> Self {
+		let hash = header.hash();
+		Body {
+			header: header,
+			hash: hash,
+		}
+	}
+
 	/// Check a response for this block body.
 	pub fn check_response(&self, body: &[u8]) -> Result<encoded::Block, Error> {
 		let body_view = UntrustedRlp::new(&body);
@@ -179,6 +209,28 @@ impl Account {
 	}
 }
 
+/// Request for account code.
+pub struct Code {
+	/// Block hash, number pair.
+	pub block_id: (H256, u64),
+	/// Address requested.
+	pub address: Address,
+	/// Account's code hash.
+	pub code_hash: H256,
+}
+
+impl Code {
+	/// Check a response with code against the code hash.
+	pub fn check_response(&self, code: &[u8]) -> Result<(), Error> {
+		let found_hash = code.sha3();
+		if found_hash == self.code_hash {
+			Ok(())
+		} else {
+			Err(Error::WrongHash(self.code_hash, found_hash))
+		}
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
@@ -191,6 +243,11 @@ mod tests {
 	use ethcore::encoded;
 	use ethcore::receipt::Receipt;
 
+	#[test]
+	fn no_invalid_header_by_number() {
+		assert!(HeaderByNumber::new(0, Default::default()).is_none())
+	}
+
 	#[test]
 	fn check_header_by_number() {
 		use ::cht;
@@ -213,10 +270,7 @@ mod tests {
 		};
 
 		let proof = cht.prove(10_000, 0).unwrap().unwrap();
-		let req = HeaderByNumber {
+		let req = HeaderByNumber::new(10_000, cht.root()).unwrap();
-			num: 10_000,
-			cht_root: cht.root(),
-		};
 
 		let raw_header = test_client.block_header(::ethcore::ids::BlockId::Number(10_000)).unwrap();
 
@@ -319,4 +373,17 @@ mod tests {
 
 		assert!(req.check_response(&proof[..]).is_ok());
 	}
+
+	#[test]
+	fn check_code() {
+		let code = vec![1u8; 256];
+		let req = Code {
+			block_id: (Default::default(), 2),
+			address: Default::default(),
+			code_hash: ::util::Hashable::sha3(&code),
+		};
+
+		assert!(req.check_response(&code).is_ok());
+		assert!(req.check_response(&[]).is_err());
+	}
 }

ethcore/src/types/encoded.rs

@@ -28,7 +28,7 @@ use header::{BlockNumber, Header as FullHeader};
 use transaction::UnverifiedTransaction;
 use views;
 
-use util::{Address, Hashable, H256, H2048, U256};
+use util::{Address, Hashable, H256, H2048, U256, HeapSizeOf};
 use rlp::{Rlp, View};
 
 /// Owning header view.
@@ -36,6 +36,10 @@ use rlp::{Rlp, View};
 #[cfg_attr(feature = "ipc", binary)]
 pub struct Header(Vec<u8>);
 
+impl HeapSizeOf for Header {
+	fn heap_size_of_children(&self) -> usize { self.0.heap_size_of_children() }
+}
+
 impl Header {
 	/// Create a new owning header view.
 	/// Expects the data to be an RLP-encoded header -- any other case will likely lead to
@@ -116,6 +120,10 @@ impl Hashable for Header {
 #[cfg_attr(feature = "ipc", binary)]
 pub struct Body(Vec<u8>);
 
+impl HeapSizeOf for Body {
+	fn heap_size_of_children(&self) -> usize { self.0.heap_size_of_children() }
+}
+
 impl Body {
 	/// Create a new owning block body view. The raw bytes passed in must be an rlp-encoded block
 	/// body.
@@ -172,6 +180,10 @@ impl Body {
 #[cfg_attr(feature = "ipc", binary)]
 pub struct Block(Vec<u8>);
 
+impl HeapSizeOf for Block {
+	fn heap_size_of_children(&self) -> usize { self.0.heap_size_of_children() }
+}
+
 impl Block {
 	/// Create a new owning block view. The raw bytes passed in must be an rlp-encoded block.
 	pub fn new(raw: Vec<u8>) -> Self { Block(raw) }

ethcore/src/types/transaction.rs

@@ -472,6 +472,12 @@ impl PendingTransaction {
 	}
 }
 
+impl Deref for PendingTransaction {
+	type Target = SignedTransaction;
+
+	fn deref(&self) -> &SignedTransaction { &self.transaction }
+}
+
 impl From<SignedTransaction> for PendingTransaction {
 	fn from(t: SignedTransaction) -> Self {
 		PendingTransaction {

parity/rpc_apis.rs

@@ -28,6 +28,7 @@ use ethcore::miner::{Miner, ExternalMiner};
 use ethcore::snapshot::SnapshotService;
 use ethcore_rpc::{Metadata, NetworkSettings};
 use ethcore_rpc::informant::{Middleware, RpcStats, ClientNotifier};
+use ethcore_rpc::dispatch::FullDispatcher;
 use ethsync::{ManageNetwork, SyncProvider};
 use hash_fetch::fetch::Client as FetchClient;
 use jsonrpc_core::{MetaIoHandler};
@@ -176,10 +177,11 @@ macro_rules! add_signing_methods {
 		{
 			let handler = &mut $handler;
 			let deps = &$deps;
+			let dispatcher = FullDispatcher::new(Arc::downgrade(&deps.client), Arc::downgrade(&deps.miner));
 			if deps.signer_service.is_enabled() {
-				handler.extend_with($namespace::to_delegate(SigningQueueClient::new(&deps.signer_service, &deps.client, &deps.miner, &deps.secret_store)))
+				handler.extend_with($namespace::to_delegate(SigningQueueClient::new(&deps.signer_service, dispatcher, &deps.secret_store)))
 			} else {
-				handler.extend_with($namespace::to_delegate(SigningUnsafeClient::new(&deps.client, &deps.secret_store, &deps.miner)))
+				handler.extend_with($namespace::to_delegate(SigningUnsafeClient::new(&deps.secret_store, dispatcher)))
 			}
 		}
 	}
@@ -194,6 +196,8 @@ pub fn setup_rpc(stats: Arc<RpcStats>, deps: Arc<Dependencies>, apis: ApiSet) ->
 
 	// it's turned into vector, cause ont of the cases requires &[]
 	let apis = apis.list_apis().into_iter().collect::<Vec<_>>();
+	let dispatcher = FullDispatcher::new(Arc::downgrade(&deps.client), Arc::downgrade(&deps.miner));
+
 	for api in &apis {
 		match *api {
 			Api::Web3 => {
@@ -223,10 +227,10 @@ pub fn setup_rpc(stats: Arc<RpcStats>, deps: Arc<Dependencies>, apis: ApiSet) ->
 				add_signing_methods!(EthSigning, handler, deps);
 			},
 			Api::Personal => {
-				handler.extend_with(PersonalClient::new(&deps.secret_store, &deps.client, &deps.miner, deps.geth_compatibility).to_delegate());
+				handler.extend_with(PersonalClient::new(&deps.secret_store, dispatcher.clone(), deps.geth_compatibility).to_delegate());
 			},
 			Api::Signer => {
-				handler.extend_with(SignerClient::new(&deps.secret_store, &deps.client, &deps.miner, &deps.signer_service).to_delegate());
+				handler.extend_with(SignerClient::new(&deps.secret_store, dispatcher.clone(), &deps.signer_service).to_delegate());
 			},
 			Api::Parity => {
 				let signer = match deps.signer_service.is_enabled() {

rpc/Cargo.toml

@@ -33,6 +33,7 @@ ethash = { path = "../ethash" }
 ethsync = { path = "../sync" }
 ethjson = { path = "../json" }
 ethcore-devtools = { path = "../devtools" }
+ethcore-light = { path = "../ethcore/light" }
 parity-updater = { path = "../updater" }
 rlp = { path = "../util/rlp" }
 fetch = { path = "../util/fetch" }

rpc/src/lib.rs

@@ -33,6 +33,7 @@ extern crate ethcrypto as crypto;
 extern crate ethstore;
 extern crate ethsync;
 extern crate ethash;
+extern crate ethcore_light as light;
 extern crate transient_hashmap;
 extern crate jsonrpc_ipc_server as ipc;
 extern crate ethcore_ipc;
@@ -64,7 +65,7 @@ use jsonrpc_core::reactor::RpcHandler;
 pub use ipc::{Server as IpcServer, Error as IpcServerError};
 pub use jsonrpc_http_server::{ServerBuilder, Server, RpcServerError};
 pub mod v1;
-pub use v1::{SigningQueue, SignerService, ConfirmationsQueue, NetworkSettings, Metadata, Origin, informant};
+pub use v1::{SigningQueue, SignerService, ConfirmationsQueue, NetworkSettings, Metadata, Origin, informant, dispatch};
 pub use v1::block_import::is_major_importing;
 
 /// Start http server asynchronously and returns result with `Server` handle on success or an error.

rpc/src/v1/helpers/dispatch.rs

@@ -14,11 +14,15 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
+//! Utilities and helpers for transaction dispatch.
+
 use std::fmt::Debug;
 use std::ops::Deref;
+use std::sync::Weak;
+
+use futures::{future, Future, BoxFuture};
 use rlp::{self, Stream};
 use util::{Address, H520, H256, U256, Uint, Bytes};
-use util::bytes::ToPretty;
 use util::sha3::Hashable;
 
 use ethkey::Signature;
@@ -38,20 +42,154 @@ use v1::types::{
 	DecryptRequest as RpcDecryptRequest,
 };
 
+/// Has the capability to dispatch, sign, and decrypt.
+///
+/// Requires a clone implementation, with the implication that it be cheap;
+/// usually just bumping a reference count or two.
+pub trait Dispatcher: Send + Sync + Clone {
+	// TODO: when ATC exist, use zero-cost
+	// type Out<T>: IntoFuture<T, Error>
+
+	/// Fill optional fields of a transaction request, fetching gas price but not nonce.
+	fn fill_optional_fields(&self, request: TransactionRequest, default_sender: Address)
+		-> BoxFuture<FilledTransactionRequest, Error>;
+
+	/// Sign the given transaction request without dispatching, fetching appropriate nonce.
+	fn sign(&self, accounts: &AccountProvider, filled: FilledTransactionRequest, password: SignWith)
+		-> BoxFuture<WithToken<SignedTransaction>, Error>;
+
+	/// "Dispatch" a local transaction.
+	fn dispatch_transaction(&self, signed_transaction: PendingTransaction) -> Result<H256, Error>;
+}
+
+/// A dispatcher which uses references to a client and miner in order to sign
+/// requests locally.
+#[derive(Debug)]
+pub struct FullDispatcher<C, M> {
+	client: Weak<C>,
+	miner: Weak<M>,
+}
+
+impl<C, M> FullDispatcher<C, M> {
+	/// Create a `FullDispatcher` from weak references to a client and miner.
+	pub fn new(client: Weak<C>, miner: Weak<M>) -> Self {
+		FullDispatcher {
+			client: client,
+			miner: miner,
+		}
+	}
+}
+
+impl<C, M> Clone for FullDispatcher<C, M> {
+	fn clone(&self) -> Self {
+		FullDispatcher {
+			client: self.client.clone(),
+			miner: self.miner.clone(),
+		}
+	}
+}
+
+impl<C: MiningBlockChainClient, M: MinerService> Dispatcher for FullDispatcher<C, M> {
+	fn fill_optional_fields(&self, request: TransactionRequest, default_sender: Address)
+		-> BoxFuture<FilledTransactionRequest, Error>
+	{
+		let (client, miner) = (take_weakf!(self.client), take_weakf!(self.miner));
+		let request = request;
+		future::ok(FilledTransactionRequest {
+			from: request.from.unwrap_or(default_sender),
+			used_default_from: request.from.is_none(),
+			to: request.to,
+			nonce: request.nonce,
+			gas_price: request.gas_price.unwrap_or_else(|| default_gas_price(&*client, &*miner)),
+			gas: request.gas.unwrap_or_else(|| miner.sensible_gas_limit()),
+			value: request.value.unwrap_or_else(|| 0.into()),
+			data: request.data.unwrap_or_else(Vec::new),
+			condition: request.condition,
+		}).boxed()
+	}
+
+	fn sign(&self, accounts: &AccountProvider, filled: FilledTransactionRequest, password: SignWith)
+		-> BoxFuture<WithToken<SignedTransaction>, Error>
+	{
+		let (client, miner) = (take_weakf!(self.client), take_weakf!(self.miner));
+		let network_id = client.signing_network_id();
+		let address = filled.from;
+		future::ok({
+			let t = Transaction {
+				nonce: filled.nonce
+					.or_else(|| miner
+						.last_nonce(&filled.from)
+						.map(|nonce| nonce + U256::one()))
+					.unwrap_or_else(|| client.latest_nonce(&filled.from)),
+
+				action: filled.to.map_or(Action::Create, Action::Call),
+				gas: filled.gas,
+				gas_price: filled.gas_price,
+				value: filled.value,
+				data: filled.data,
+			};
+
+			let hash = t.hash(network_id);
+			if accounts.is_hardware_address(address) {
+				let mut stream = rlp::RlpStream::new();
+				t.rlp_append_unsigned_transaction(&mut stream, network_id);
+				let signature = try_bf!(
+					accounts.sign_with_hardware(address, &stream.as_raw())
+						.map_err(|e| {
+							debug!(target: "miner", "Error signing transaction with hardware wallet: {}", e);
+							errors::account("Error signing transaction with hardware wallet", e)
+						})
+				);
+				let signed = try_bf!(
+					SignedTransaction::new(t.with_signature(signature, network_id))
+						.map_err(|e| {
+						  debug!(target: "miner", "Hardware wallet has produced invalid signature: {}", e);
+						  errors::account("Invalid signature generated", e)
+						})
+				);
+				WithToken::No(signed)
+			} else {
+				let signature = try_bf!(signature(accounts, address, hash, password));
+				signature.map(|sig| {
+					SignedTransaction::new(t.with_signature(sig, network_id))
+						.expect("Transaction was signed by AccountsProvider; it never produces invalid signatures; qed")
+				})
+			}
+		}).boxed()
+	}
+
+	fn dispatch_transaction(&self, signed_transaction: PendingTransaction) -> Result<H256, Error> {
+		let hash = signed_transaction.transaction.hash();
+
+		take_weak!(self.miner).import_own_transaction(&*take_weak!(self.client), signed_transaction)
+			.map_err(errors::from_transaction_error)
+			.map(|_| hash)
+	}
+}
+
+/// default MAC to use.
 pub const DEFAULT_MAC: [u8; 2] = [0, 0];
 
-type AccountToken = String;
+/// Single-use account token.
+pub type AccountToken = String;
 
+/// Values used to unlock accounts for signing.
 #[derive(Debug, Clone, PartialEq)]
 pub enum SignWith {
+	/// Nothing -- implies the account is already unlocked.
 	Nothing,
+	/// Unlock with password.
 	Password(String),
+	/// Unlock with single-use token.
 	Token(AccountToken),
 }
 
+/// A value, potentially accompanied by a signing token.
 #[derive(Debug)]
 pub enum WithToken<T: Debug> {
+	/// No token.
 	No(T),
+	/// With token.
 	Yes(T, AccountToken),
 }
 
@@ -67,6 +205,7 @@ impl<T: Debug> Deref for WithToken<T> {
 }
 
 impl<T: Debug> WithToken<T> {
+	/// Map the value with the given closure, preserving the token.
 	pub fn map<S, F>(self, f: F) -> WithToken<S> where
 		S: Debug,
 		F: FnOnce(T) -> S,
@@ -77,12 +216,21 @@ impl<T: Debug> WithToken<T> {
 		}
 	}
 
+	/// Convert into inner value, ignoring possible token.
 	pub fn into_value(self) -> T {
 		match self {
 			WithToken::No(v) => v,
 			WithToken::Yes(v, _) => v,
 		}
 	}
+
+	/// Convert the `WithToken` into a tuple.
+	pub fn into_tuple(self) -> (T, Option<AccountToken>) {
+		match self {
+			WithToken::No(v) => (v, None),
+			WithToken::Yes(v, token) => (v, Some(token))
+		}
+	}
 }
 
 impl<T: Debug> From<(T, AccountToken)> for WithToken<T> {
@@ -91,30 +239,49 @@ impl<T: Debug> From<(T, AccountToken)> for WithToken<T> {
 	}
 }
 
-pub fn execute<C, M>(client: &C, miner: &M, accounts: &AccountProvider, payload: ConfirmationPayload, pass: SignWith) -> Result<WithToken<ConfirmationResponse>, Error>
+impl<T: Debug> From<(T, Option<AccountToken>)> for WithToken<T> {
-	where C: MiningBlockChainClient, M: MinerService
+	fn from(tuple: (T, Option<AccountToken>)) -> Self {
-{
+		match tuple.1 {
+			Some(token) => WithToken::Yes(tuple.0, token),
+			None => WithToken::No(tuple.0),
+		}
+	}
+}
+
+/// Execute a confirmation payload.
+pub fn execute<D: Dispatcher + 'static>(
+	dispatcher: D,
+	accounts: &AccountProvider,
+	payload: ConfirmationPayload,
+	pass: SignWith
+) -> BoxFuture<WithToken<ConfirmationResponse>, Error> {
 	match payload {
 		ConfirmationPayload::SendTransaction(request) => {
-			sign_and_dispatch(client, miner, accounts, request, pass)
+			let condition = request.condition.clone().map(Into::into);
-				.map(|result| result
+			dispatcher.sign(accounts, request, pass)
+				.map(move |v| v.map(move |tx| PendingTransaction::new(tx, condition)))
+				.map(WithToken::into_tuple)
+				.map(|(tx, token)| (tx, token, dispatcher))
+				.and_then(|(tx, tok, dispatcher)| {
+					dispatcher.dispatch_transaction(tx)
 						.map(RpcH256::from)
 						.map(ConfirmationResponse::SendTransaction)
-				)
+						.map(move |h| WithToken::from((h, tok)))
+				}).boxed()
 		},
 		ConfirmationPayload::SignTransaction(request) => {
-			sign_no_dispatch(client, miner, accounts, request, pass)
+			dispatcher.sign(accounts, request, pass)
 				.map(|result| result
 					.map(RpcRichRawTransaction::from)
 					.map(ConfirmationResponse::SignTransaction)
-				)
+				).boxed()
 		},
 		ConfirmationPayload::Signature(address, mut data) => {
 			let mut message_data =
 				format!("\x19Ethereum Signed Message:\n{}", data.len())
 				.into_bytes();
 			message_data.append(&mut data);
-			signature(accounts, address, message_data.sha3(), pass)
+			let res = signature(accounts, address, message_data.sha3(), pass)
 				.map(|result| result
 					.map(|rsv| {
 						let mut vrs = [0u8; 65];
@@ -126,14 +293,16 @@ pub fn execute<C, M>(client: &C, miner: &M, accounts: &AccountProvider, payload:
 					})
 					.map(RpcH520::from)
 					.map(ConfirmationResponse::Signature)
-				)
+				);
+			future::done(res).boxed()
 		},
 		ConfirmationPayload::Decrypt(address, data) => {
-			decrypt(accounts, address, data, pass)
+			let res = decrypt(accounts, address, data, pass)
 				.map(|result| result
 					.map(RpcBytes)
 					.map(ConfirmationResponse::Decrypt)
-				)
+				);
+			future::done(res).boxed()
 		},
 	}
 }
@@ -160,120 +329,34 @@ fn decrypt(accounts: &AccountProvider, address: Address, msg: Bytes, password: S
 	})
 }
 
-pub fn dispatch_transaction<C, M>(client: &C, miner: &M, signed_transaction: PendingTransaction) -> Result<H256, Error>
+/// Extract the default gas price from a client and miner.
-	where C: MiningBlockChainClient, M: MinerService {
-	let hash = signed_transaction.transaction.hash();
-
-	miner.import_own_transaction(client, signed_transaction)
-		.map_err(errors::from_transaction_error)
-		.map(|_| hash)
-}
-
-pub fn sign_no_dispatch<C, M>(client: &C, miner: &M, accounts: &AccountProvider, filled: FilledTransactionRequest, password: SignWith) -> Result<WithToken<SignedTransaction>, Error>
-	where C: MiningBlockChainClient, M: MinerService {
-
-	let network_id = client.signing_network_id();
-	let address = filled.from;
-	let signed_transaction = {
-		let t = Transaction {
-			nonce: filled.nonce
-				.or_else(|| miner
-					.last_nonce(&filled.from)
-					.map(|nonce| nonce + U256::one()))
-				.unwrap_or_else(|| client.latest_nonce(&filled.from)),
-
-			action: filled.to.map_or(Action::Create, Action::Call),
-			gas: filled.gas,
-			gas_price: filled.gas_price,
-			value: filled.value,
-			data: filled.data,
-		};
-
-		let hash = t.hash(network_id);
-		if accounts.is_hardware_address(address) {
-			let mut stream = rlp::RlpStream::new();
-			t.rlp_append_unsigned_transaction(&mut stream, network_id);
-			let signature = accounts.sign_with_hardware(address, &stream.as_raw())
-				.map_err(|e| {
-					debug!(target: "miner", "Error signing transaction with hardware wallet: {}", e);
-					errors::account("Error signing transaction with hardware wallet", e)
-				})?;
-			WithToken::No(SignedTransaction::new(t.with_signature(signature, network_id))
-				.map_err(|e| {
-				  debug!(target: "miner", "Hardware wallet has produced invalid signature: {}", e);
-				  errors::account("Invalid signature generated", e)
-				})?)
-		} else {
-			let signature = signature(accounts, address, hash, password)?;
-			signature.map(|sig| {
-				SignedTransaction::new(t.with_signature(sig, network_id))
-					.expect("Transaction was signed by AccountsProvider; it never produces invalid signatures; qed")
-			})
-		}
-	};
-	Ok(signed_transaction)
-}
-
-pub fn sign_and_dispatch<C, M>(client: &C, miner: &M, accounts: &AccountProvider, filled: FilledTransactionRequest, password: SignWith) -> Result<WithToken<H256>, Error>
-	where C: MiningBlockChainClient, M: MinerService
-{
-
-	let network_id = client.signing_network_id();
-	let condition = filled.condition.clone();
-	let signed_transaction = sign_no_dispatch(client, miner, accounts, filled, password)?;
-
-	let (signed_transaction, token) = match signed_transaction {
-		WithToken::No(signed_transaction) => (signed_transaction, None),
-		WithToken::Yes(signed_transaction, token) => (signed_transaction, Some(token)),
-	};
-
-	trace!(target: "miner", "send_transaction: dispatching tx: {} for network ID {:?}", rlp::encode(&signed_transaction).to_vec().pretty(), network_id);
-	let pending_transaction = PendingTransaction::new(signed_transaction, condition.map(Into::into));
-	dispatch_transaction(&*client, &*miner, pending_transaction).map(|hash| {
-		match token {
-			Some(ref token) => WithToken::Yes(hash, token.clone()),
-			None => WithToken::No(hash),
-		}
-	})
-}
-
-pub fn fill_optional_fields<C, M>(request: TransactionRequest, default_sender: Address, client: &C, miner: &M) -> FilledTransactionRequest
-	where C: MiningBlockChainClient, M: MinerService
-{
-	FilledTransactionRequest {
-		from: request.from.unwrap_or(default_sender),
-		used_default_from: request.from.is_none(),
-		to: request.to,
-		nonce: request.nonce,
-		gas_price: request.gas_price.unwrap_or_else(|| default_gas_price(client, miner)),
-		gas: request.gas.unwrap_or_else(|| miner.sensible_gas_limit()),
-		value: request.value.unwrap_or_else(|| 0.into()),
-		data: request.data.unwrap_or_else(Vec::new),
-		condition: request.condition,
-	}
-}
-
 pub fn default_gas_price<C, M>(client: &C, miner: &M) -> U256
 	where C: MiningBlockChainClient, M: MinerService
 {
 	client.gas_price_median(100).unwrap_or_else(|| miner.sensible_gas_price())
 }
 
-pub fn from_rpc<C, M>(payload: RpcConfirmationPayload, default_account: Address, client: &C, miner: &M) -> ConfirmationPayload
+/// Convert RPC confirmation payload to signer confirmation payload.
-	where C: MiningBlockChainClient, M: MinerService {
+/// May need to resolve in the future to fetch things like gas price.
-
+pub fn from_rpc<D>(payload: RpcConfirmationPayload, default_account: Address, dispatcher: &D) -> BoxFuture<ConfirmationPayload, Error>
+	where D: Dispatcher
+{
 	match payload {
 		RpcConfirmationPayload::SendTransaction(request) => {
-			ConfirmationPayload::SendTransaction(fill_optional_fields(request.into(), default_account, client, miner))
+			dispatcher.fill_optional_fields(request.into(), default_account)
+				.map(ConfirmationPayload::SendTransaction)
+				.boxed()
 		},
 		RpcConfirmationPayload::SignTransaction(request) => {
-			ConfirmationPayload::SignTransaction(fill_optional_fields(request.into(), default_account, client, miner))
+			dispatcher.fill_optional_fields(request.into(), default_account)
+				.map(ConfirmationPayload::SignTransaction)
+				.boxed()
 		},
 		RpcConfirmationPayload::Decrypt(RpcDecryptRequest { address, msg }) => {
-			ConfirmationPayload::Decrypt(address.into(), msg.into())
+			future::ok(ConfirmationPayload::Decrypt(address.into(), msg.into())).boxed()
 		},
 		RpcConfirmationPayload::Signature(RpcSignRequest { address, data }) => {
-			ConfirmationPayload::Signature(address.into(), data.into())
+			future::ok(ConfirmationPayload::Signature(address.into(), data.into())).boxed()
 		},
 	}
 }

rpc/src/v1/helpers/mod.rs

@@ -28,6 +28,7 @@ mod requests;
 mod signer;
 mod signing_queue;
 
+pub use self::dispatch::{Dispatcher, FullDispatcher};
 pub use self::network_settings::NetworkSettings;
 pub use self::poll_manager::PollManager;
 pub use self::poll_filter::{PollFilter, limit_logs};

rpc/src/v1/impls/eth.rs

@@ -22,7 +22,7 @@ use std::thread;
 use std::time::{Instant, Duration};
 use std::sync::{Arc, Weak};
 
-use futures::{self, BoxFuture, Future};
+use futures::{self, future, BoxFuture, Future};
 use rlp::{self, UntrustedRlp, View};
 use time::get_time;
 use util::{H160, H256, Address, FixedHash, U256, H64, Uint};
@@ -38,7 +38,7 @@ use ethcore::filter::Filter as EthcoreFilter;
 use ethcore::header::{Header as BlockHeader, BlockNumber as EthBlockNumber};
 use ethcore::log_entry::LogEntry;
 use ethcore::miner::{MinerService, ExternalMinerService};
-use ethcore::transaction::{Transaction as EthTransaction, SignedTransaction, PendingTransaction, Action};
+use ethcore::transaction::{Transaction as EthTransaction, SignedTransaction, Action};
 use ethcore::snapshot::SnapshotService;
 use ethsync::{SyncProvider};
 
@@ -46,7 +46,7 @@ use jsonrpc_core::Error;
 use jsonrpc_macros::Trailing;
 
 use v1::helpers::{CallRequest as CRequest, errors, limit_logs};
-use v1::helpers::dispatch::{dispatch_transaction, default_gas_price};
+use v1::helpers::dispatch::{Dispatcher, FullDispatcher, default_gas_price};
 use v1::helpers::block_import::is_major_importing;
 use v1::traits::Eth;
 use v1::types::{
@@ -144,7 +144,7 @@ impl<C, SN: ?Sized, S: ?Sized, M, EM> EthClient<C, SN, S, M, EM> where
 						logs_bloom: view.log_bloom().into(),
 						timestamp: view.timestamp().into(),
 						difficulty: view.difficulty().into(),
-						total_difficulty: total_difficulty.into(),
+						total_difficulty: Some(total_difficulty.into()),
 						seal_fields: view.seal().into_iter().map(Into::into).collect(),
 						uncles: block.uncle_hashes().into_iter().map(Into::into).collect(),
 						transactions: match include_txs {
@@ -194,7 +194,7 @@ impl<C, SN: ?Sized, S: ?Sized, M, EM> EthClient<C, SN, S, M, EM> where
 				logs_bloom: uncle.log_bloom().clone().into(),
 				timestamp: uncle.timestamp().into(),
 				difficulty: uncle.difficulty().clone().into(),
-				total_difficulty: (uncle.difficulty().clone() + parent_difficulty).into(),
+				total_difficulty: Some((uncle.difficulty().clone() + parent_difficulty).into()),
 				receipts_root: uncle.receipts_root().clone().into(),
 				extra_data: uncle.extra_data().clone().into(),
 				seal_fields: uncle.seal().into_iter().cloned().map(Into::into).collect(),
@@ -356,113 +356,119 @@ impl<C, SN: ?Sized, S: ?Sized, M, EM> Eth for EthClient<C, SN, S, M, EM> where
 		Ok(RpcU256::from(take_weak!(self.client).chain_info().best_block_number))
 	}
 
-	fn balance(&self, address: RpcH160, num: Trailing<BlockNumber>) -> Result<RpcU256, Error> {
+	fn balance(&self, address: RpcH160, num: Trailing<BlockNumber>) -> BoxFuture<RpcU256, Error> {
 		let address = address.into();
-		match num.0 {
-			BlockNumber::Pending => Ok(take_weak!(self.miner).balance(&*take_weak!(self.client), &address).into()),
-			id => {
-				let client = take_weak!(self.client);
 
-				check_known(&*client, id.clone())?;
+		let res = match num.0.clone() {
+			BlockNumber::Pending => Ok(take_weakf!(self.miner).balance(&*take_weakf!(self.client), &address).into()),
+			id => {
+				let client = take_weakf!(self.client);
+
+				try_bf!(check_known(&*client, id.clone()));
 				match client.balance(&address, id.into()) {
 					Some(balance) => Ok(balance.into()),
 					None => Err(errors::state_pruned()),
 				}
 			}
-		}
+		};
+
+		future::done(res).boxed()
 	}
 
-	fn storage_at(&self, address: RpcH160, pos: RpcU256, num: Trailing<BlockNumber>) -> Result<RpcH256, Error> {
+	fn storage_at(&self, address: RpcH160, pos: RpcU256, num: Trailing<BlockNumber>) -> BoxFuture<RpcH256, Error> {
 		let address: Address = RpcH160::into(address);
 		let position: U256 = RpcU256::into(pos);
-		match num.0 {
-			BlockNumber::Pending => Ok(take_weak!(self.miner).storage_at(&*take_weak!(self.client), &address, &H256::from(position)).into()),
-			id => {
-				let client = take_weak!(self.client);
 
-				check_known(&*client, id.clone())?;
+		let res = match num.0.clone() {
+			BlockNumber::Pending => Ok(take_weakf!(self.miner).storage_at(&*take_weakf!(self.client), &address, &H256::from(position)).into()),
+			id => {
+				let client = take_weakf!(self.client);
+
+				try_bf!(check_known(&*client, id.clone()));
 				match client.storage_at(&address, &H256::from(position), id.into()) {
 					Some(s) => Ok(s.into()),
 					None => Err(errors::state_pruned()),
 				}
 			}
-		}
+		};
+
+		future::done(res).boxed()
 	}
 
-	fn transaction_count(&self, address: RpcH160, num: Trailing<BlockNumber>) -> Result<RpcU256, Error> {
+	fn transaction_count(&self, address: RpcH160, num: Trailing<BlockNumber>) -> BoxFuture<RpcU256, Error> {
 		let address: Address = RpcH160::into(address);
-		match num.0 {
+		let res = match num.0.clone() {
-			BlockNumber::Pending => Ok(take_weak!(self.miner).nonce(&*take_weak!(self.client), &address).into()),
+			BlockNumber::Pending => Ok(take_weakf!(self.miner).nonce(&*take_weakf!(self.client), &address).into()),
 			id => {
-				let client = take_weak!(self.client);
+				let client = take_weakf!(self.client);
 
-				check_known(&*client, id.clone())?;
+				try_bf!(check_known(&*client, id.clone()));
 				match client.nonce(&address, id.into()) {
 					Some(nonce) => Ok(nonce.into()),
 					None => Err(errors::state_pruned()),
 				}
 			}
-		}
+		};
+
+		future::done(res).boxed()
 	}
 
-	fn block_transaction_count_by_hash(&self, hash: RpcH256) -> Result<Option<RpcU256>, Error> {
+	fn block_transaction_count_by_hash(&self, hash: RpcH256) -> BoxFuture<Option<RpcU256>, Error> {
-		Ok(
+		future::ok(take_weakf!(self.client).block(BlockId::Hash(hash.into()))
-			take_weak!(self.client).block(BlockId::Hash(hash.into()))
+			.map(|block| block.transactions_count().into())).boxed()
-				.map(|block| block.transactions_count().into())
-		)
 	}
 
-	fn block_transaction_count_by_number(&self, num: BlockNumber) -> Result<Option<RpcU256>, Error> {
+	fn block_transaction_count_by_number(&self, num: BlockNumber) -> BoxFuture<Option<RpcU256>, Error> {
-		match num {
+		future::ok(match num {
-			BlockNumber::Pending => Ok(Some(
+			BlockNumber::Pending => Some(
-				take_weak!(self.miner).status().transactions_in_pending_block.into()
+				take_weakf!(self.miner).status().transactions_in_pending_block.into()
-			)),
-			_ => Ok(
-				take_weak!(self.client).block(num.into())
-					.map(|block| block.transactions_count().into())
-				)
-		}
-	}
-
-	fn block_uncles_count_by_hash(&self, hash: RpcH256) -> Result<Option<RpcU256>, Error> {
-		Ok(
-			take_weak!(self.client).block(BlockId::Hash(hash.into()))
-				.map(|block| block.uncles_count().into())
-		)
-	}
-
-	fn block_uncles_count_by_number(&self, num: BlockNumber) -> Result<Option<RpcU256>, Error> {
-		match num {
-			BlockNumber::Pending => Ok(Some(0.into())),
-			_ => Ok(
-				take_weak!(self.client).block(num.into())
-					.map(|block| block.uncles_count().into())
 			),
-		}
+			_ =>
+				take_weakf!(self.client).block(num.into())
+					.map(|block| block.transactions_count().into())
+		}).boxed()
 	}
 
-	fn code_at(&self, address: RpcH160, num: Trailing<BlockNumber>) -> Result<Bytes, Error> {
+	fn block_uncles_count_by_hash(&self, hash: RpcH256) -> BoxFuture<Option<RpcU256>, Error> {
+			future::ok(take_weakf!(self.client).block(BlockId::Hash(hash.into()))
+				.map(|block| block.uncles_count().into()))
+				.boxed()
+	}
+
+	fn block_uncles_count_by_number(&self, num: BlockNumber) -> BoxFuture<Option<RpcU256>, Error> {
+		future::ok(match num {
+			BlockNumber::Pending => Some(0.into()),
+			_ => take_weakf!(self.client).block(num.into())
+					.map(|block| block.uncles_count().into()
+			),
+		}).boxed()
+	}
+
+	fn code_at(&self, address: RpcH160, num: Trailing<BlockNumber>) -> BoxFuture<Bytes, Error> {
 		let address: Address = RpcH160::into(address);
-		match num.0 {
-			BlockNumber::Pending => Ok(take_weak!(self.miner).code(&*take_weak!(self.client), &address).map_or_else(Bytes::default, Bytes::new)),
-			id => {
-				let client = take_weak!(self.client);
 
-				check_known(&*client, id.clone())?;
+		let res = match num.0.clone() {
+			BlockNumber::Pending => Ok(take_weakf!(self.miner).code(&*take_weakf!(self.client), &address).map_or_else(Bytes::default, Bytes::new)),
+			id => {
+				let client = take_weakf!(self.client);
+
+				try_bf!(check_known(&*client, id.clone()));
 				match client.code(&address, id.into()) {
 					Some(code) => Ok(code.map_or_else(Bytes::default, Bytes::new)),
 					None => Err(errors::state_pruned()),
 				}
 			}
-		}
+		};
+
+		future::done(res).boxed()
 	}
 
-	fn block_by_hash(&self, hash: RpcH256, include_txs: bool) -> Result<Option<RichBlock>, Error> {
+	fn block_by_hash(&self, hash: RpcH256, include_txs: bool) -> BoxFuture<Option<RichBlock>, Error> {
-		self.block(BlockId::Hash(hash.into()), include_txs)
+		future::done(self.block(BlockId::Hash(hash.into()), include_txs)).boxed()
 	}
 
-	fn block_by_number(&self, num: BlockNumber, include_txs: bool) -> Result<Option<RichBlock>, Error> {
+	fn block_by_number(&self, num: BlockNumber, include_txs: bool) -> BoxFuture<Option<RichBlock>, Error> {
-		self.block(num.into(), include_txs)
+		future::done(self.block(num.into(), include_txs)).boxed()
 	}
 
 	fn transaction_by_hash(&self, hash: RpcH256) -> Result<Option<Transaction>, Error> {
@@ -603,7 +609,8 @@ impl<C, SN: ?Sized, S: ?Sized, M, EM> Eth for EthClient<C, SN, S, M, EM> where
 			.map_err(errors::from_rlp_error)
 			.and_then(|tx| SignedTransaction::new(tx).map_err(errors::from_transaction_error))
 			.and_then(|signed_transaction| {
-				dispatch_transaction(&*take_weak!(self.client), &*take_weak!(self.miner), PendingTransaction::new(signed_transaction, None))
+				FullDispatcher::new(self.client.clone(), self.miner.clone())
+					.dispatch_transaction(signed_transaction.into())
 			})
 			.map(Into::into)
 	}

rpc/src/v1/impls/light/eth.rs

@@ -0,0 +1,373 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Eth RPC interface for the light client.
+
+// TODO: remove when complete.
+#![allow(unused_imports, unused_variables)]
+
+use std::sync::Arc;
+
+use jsonrpc_core::Error;
+use jsonrpc_macros::Trailing;
+
+use light::client::Client as LightClient;
+use light::cht;
+use light::on_demand::{request, OnDemand};
+
+use ethcore::account_provider::{AccountProvider, DappId};
+use ethcore::basic_account::BasicAccount;
+use ethcore::encoded;
+use ethcore::ids::BlockId;
+use ethsync::LightSync;
+use util::sha3::{SHA3_NULL_RLP, SHA3_EMPTY_LIST_RLP};
+use util::U256;
+
+use futures::{future, Future, BoxFuture};
+use futures::sync::oneshot;
+
+use v1::helpers::{CallRequest as CRequest, errors, limit_logs};
+use v1::helpers::block_import::is_major_importing;
+use v1::traits::Eth;
+use v1::types::{
+	RichBlock, Block, BlockTransactions, BlockNumber, Bytes, SyncStatus, SyncInfo,
+	Transaction, CallRequest, Index, Filter, Log, Receipt, Work,
+	H64 as RpcH64, H256 as RpcH256, H160 as RpcH160, U256 as RpcU256,
+};
+use v1::metadata::Metadata;
+
+use util::Address;
+
+/// Light client `ETH` RPC.
+pub struct EthClient {
+	sync: Arc<LightSync>,
+	client: Arc<LightClient>,
+	on_demand: Arc<OnDemand>,
+	accounts: Arc<AccountProvider>,
+}
+
+// helper for internal error: no network context.
+fn err_no_context() -> Error {
+	errors::internal("network service detached", "")
+}
+
+// helper for internal error: on demand sender cancelled.
+fn err_premature_cancel(_cancel: oneshot::Canceled) -> Error {
+	errors::internal("on-demand sender prematurely cancelled", "")
+}
+
+impl EthClient {
+	/// Create a new `EthClient` with a handle to the light sync instance, client,
+	/// and on-demand request service, which is assumed to be attached as a handler.
+	pub fn new(
+		sync: Arc<LightSync>,
+		client: Arc<LightClient>,
+		on_demand: Arc<OnDemand>,
+		accounts: Arc<AccountProvider>,
+	) -> Self {
+		EthClient {
+			sync: sync,
+			client: client,
+			on_demand: on_demand,
+			accounts: accounts,
+		}
+	}
+
+	/// Get a block header from the on demand service or client, or error.
+	fn header(&self, id: BlockId) -> BoxFuture<Option<encoded::Header>, Error> {
+		if let Some(h) = self.client.block_header(id) {
+			return future::ok(Some(h)).boxed()
+		}
+
+		let maybe_future = match id {
+			BlockId::Number(n) => {
+				let cht_root = cht::block_to_cht_number(n).and_then(|cn| self.client.cht_root(cn as usize));
+				match cht_root {
+					None => return future::ok(None).boxed(),
+					Some(root) => {
+						let req = request::HeaderByNumber::new(n, root)
+							.expect("only fails for 0; client always stores genesis; client already queried; qed");
+
+						self.sync.with_context(|ctx|
+							self.on_demand.header_by_number(ctx, req)
+								.map(|(h, _)| Some(h))
+								.map_err(err_premature_cancel)
+								.boxed()
+						)
+					}
+				}
+			}
+			BlockId::Hash(h) => {
+				self.sync.with_context(|ctx|
+					self.on_demand.header_by_hash(ctx, request::HeaderByHash(h))
+						.then(|res| future::done(match res {
+							Ok(h) => Ok(Some(h)),
+							Err(e) => Err(err_premature_cancel(e)),
+						}))
+						.boxed()
+				)
+			}
+			_ => None, // latest, earliest, and pending will have all already returned.
+		};
+
+		// todo: cache returned values (header, TD)
+		match maybe_future {
+			Some(recv) => recv,
+			None => future::err(err_no_context()).boxed()
+		}
+	}
+
+	// helper for getting account info at a given block.
+	fn account(&self, address: Address, id: BlockId) -> BoxFuture<Option<BasicAccount>, Error> {
+		let (sync, on_demand) = (self.sync.clone(), self.on_demand.clone());
+
+		self.header(id).and_then(move |header| {
+			let header = match header {
+				None => return future::ok(None).boxed(),
+				Some(hdr) => hdr,
+			};
+
+			sync.with_context(|ctx| on_demand.account(ctx, request::Account {
+				header: header,
+				address: address,
+			}).map(Some))
+				.map(|x| x.map_err(err_premature_cancel).boxed())
+				.unwrap_or_else(|| future::err(err_no_context()).boxed())
+		}).boxed()
+	}
+}
+
+impl Eth for EthClient {
+	type Metadata = Metadata;
+
+	fn protocol_version(&self) -> Result<String, Error> {
+		Ok(format!("{}", ::light::net::MAX_PROTOCOL_VERSION))
+	}
+
+	fn syncing(&self) -> Result<SyncStatus, Error> {
+		rpc_unimplemented!()
+	}
+
+	fn author(&self, _meta: Self::Metadata) -> BoxFuture<RpcH160, Error> {
+		future::ok(Default::default()).boxed()
+	}
+
+	fn is_mining(&self) -> Result<bool, Error> {
+		Ok(false)
+	}
+
+	fn hashrate(&self) -> Result<RpcU256, Error> {
+		Ok(Default::default())
+	}
+
+	fn gas_price(&self) -> Result<RpcU256, Error> {
+		Ok(Default::default())
+	}
+
+	fn accounts(&self, meta: Metadata) -> BoxFuture<Vec<RpcH160>, Error> {
+		let dapp: DappId = meta.dapp_id.unwrap_or_default().into();
+
+		let accounts = self.accounts
+			.note_dapp_used(dapp.clone())
+			.and_then(|_| self.accounts.dapps_addresses(dapp))
+			.map_err(|e| errors::internal("Could not fetch accounts.", e))
+			.map(|accs| accs.into_iter().map(Into::<RpcH160>::into).collect());
+
+		future::done(accounts).boxed()
+	}
+
+	fn block_number(&self) -> Result<RpcU256, Error> {
+		Ok(self.client.chain_info().best_block_number.into())
+	}
+
+	fn balance(&self, address: RpcH160, num: Trailing<BlockNumber>) -> BoxFuture<RpcU256, Error> {
+		self.account(address.into(), num.0.into())
+			.map(|acc| acc.map_or(0.into(), |a| a.balance).into()).boxed()
+	}
+
+	fn storage_at(&self, _address: RpcH160, _key: RpcU256, _num: Trailing<BlockNumber>) -> BoxFuture<RpcH256, Error> {
+		future::err(errors::unimplemented(None)).boxed()
+	}
+
+	fn block_by_hash(&self, hash: RpcH256, include_txs: bool) -> BoxFuture<Option<RichBlock>, Error> {
+		future::err(errors::unimplemented(None)).boxed()
+	}
+
+	fn block_by_number(&self, num: BlockNumber, include_txs: bool) -> BoxFuture<Option<RichBlock>, Error> {
+		future::err(errors::unimplemented(None)).boxed()
+	}
+
+	fn transaction_count(&self, address: RpcH160, num: Trailing<BlockNumber>) -> BoxFuture<RpcU256, Error> {
+		self.account(address.into(), num.0.into())
+			.map(|acc| acc.map_or(0.into(), |a| a.nonce).into()).boxed()
+	}
+
+	fn block_transaction_count_by_hash(&self, hash: RpcH256) -> BoxFuture<Option<RpcU256>, Error> {
+		let (sync, on_demand) = (self.sync.clone(), self.on_demand.clone());
+
+		self.header(BlockId::Hash(hash.into())).and_then(move |hdr| {
+			let hdr = match hdr {
+				None => return future::ok(None).boxed(),
+				Some(hdr) => hdr,
+			};
+
+			if hdr.transactions_root() == SHA3_NULL_RLP {
+				future::ok(Some(U256::from(0).into())).boxed()
+			} else {
+				sync.with_context(|ctx| on_demand.block(ctx, request::Body::new(hdr)))
+					.map(|x| x.map(|b| Some(U256::from(b.transactions_count()).into())))
+					.map(|x| x.map_err(err_premature_cancel).boxed())
+					.unwrap_or_else(|| future::err(err_no_context()).boxed())
+			}
+		}).boxed()
+	}
+
+	fn block_transaction_count_by_number(&self, num: BlockNumber) -> BoxFuture<Option<RpcU256>, Error> {
+		let (sync, on_demand) = (self.sync.clone(), self.on_demand.clone());
+
+		self.header(num.into()).and_then(move |hdr| {
+			let hdr = match hdr {
+				None => return future::ok(None).boxed(),
+				Some(hdr) => hdr,
+			};
+
+			if hdr.transactions_root() == SHA3_NULL_RLP {
+				future::ok(Some(U256::from(0).into())).boxed()
+			} else {
+				sync.with_context(|ctx| on_demand.block(ctx, request::Body::new(hdr)))
+					.map(|x| x.map(|b| Some(U256::from(b.transactions_count()).into())))
+					.map(|x| x.map_err(err_premature_cancel).boxed())
+					.unwrap_or_else(|| future::err(err_no_context()).boxed())
+			}
+		}).boxed()
+	}
+
+	fn block_uncles_count_by_hash(&self, hash: RpcH256) -> BoxFuture<Option<RpcU256>, Error> {
+		let (sync, on_demand) = (self.sync.clone(), self.on_demand.clone());
+
+		self.header(BlockId::Hash(hash.into())).and_then(move |hdr| {
+			let hdr = match hdr {
+				None => return future::ok(None).boxed(),
+				Some(hdr) => hdr,
+			};
+
+			if hdr.uncles_hash() == SHA3_EMPTY_LIST_RLP {
+				future::ok(Some(U256::from(0).into())).boxed()
+			} else {
+				sync.with_context(|ctx| on_demand.block(ctx, request::Body::new(hdr)))
+					.map(|x| x.map(|b| Some(U256::from(b.uncles_count()).into())))
+					.map(|x| x.map_err(err_premature_cancel).boxed())
+					.unwrap_or_else(|| future::err(err_no_context()).boxed())
+			}
+		}).boxed()
+	}
+
+	fn block_uncles_count_by_number(&self, num: BlockNumber) -> BoxFuture<Option<RpcU256>, Error> {
+		let (sync, on_demand) = (self.sync.clone(), self.on_demand.clone());
+
+		self.header(num.into()).and_then(move |hdr| {
+			let hdr = match hdr {
+				None => return future::ok(None).boxed(),
+				Some(hdr) => hdr,
+			};
+
+			if hdr.uncles_hash() == SHA3_EMPTY_LIST_RLP {
+				future::ok(Some(U256::from(0).into())).boxed()
+			} else {
+				sync.with_context(|ctx| on_demand.block(ctx, request::Body::new(hdr)))
+					.map(|x| x.map(|b| Some(U256::from(b.uncles_count()).into())))
+					.map(|x| x.map_err(err_premature_cancel).boxed())
+					.unwrap_or_else(|| future::err(err_no_context()).boxed())
+			}
+		}).boxed()
+	}
+
+	fn code_at(&self, address: RpcH160, num: Trailing<BlockNumber>) -> BoxFuture<Bytes, Error> {
+		future::err(errors::unimplemented(None)).boxed()
+	}
+
+	fn send_raw_transaction(&self, raw: Bytes) -> Result<RpcH256, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn submit_transaction(&self, raw: Bytes) -> Result<RpcH256, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn call(&self, req: CallRequest, num: Trailing<BlockNumber>) -> Result<Bytes, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn estimate_gas(&self, req: CallRequest, num: Trailing<BlockNumber>) -> Result<RpcU256, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn transaction_by_hash(&self, hash: RpcH256) -> Result<Option<Transaction>, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn transaction_by_block_hash_and_index(&self, hash: RpcH256, idx: Index) -> Result<Option<Transaction>, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn transaction_by_block_number_and_index(&self, num: BlockNumber, idx: Index) -> Result<Option<Transaction>, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn transaction_receipt(&self, hash: RpcH256) -> Result<Option<Receipt>, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn uncle_by_block_hash_and_index(&self, hash: RpcH256, idx: Index) -> Result<Option<RichBlock>, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn uncle_by_block_number_and_index(&self, num: BlockNumber, idx: Index) -> Result<Option<RichBlock>, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn compilers(&self) -> Result<Vec<String>, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn compile_lll(&self, _code: String) -> Result<Bytes, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn compile_solidity(&self, _code: String) -> Result<Bytes, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn compile_serpent(&self, _code: String) -> Result<Bytes, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn logs(&self, _filter: Filter) -> Result<Vec<Log>, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn work(&self, _timeout: Trailing<u64>) -> Result<Work, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn submit_work(&self, _nonce: RpcH64, _pow_hash: RpcH256, _mix_hash: RpcH256) -> Result<bool, Error> {
+		Err(errors::unimplemented(None))
+	}
+
+	fn submit_hashrate(&self, _rate: RpcU256, _id: RpcH256) -> Result<bool, Error> {
+		Err(errors::unimplemented(None))
+	}
+}

rpc/src/v1/impls/light/mod.rs

@@ -0,0 +1,21 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! RPC implementations for the light client.
+
+pub mod eth;
+
+pub use self::eth::EthClient;

rpc/src/v1/impls/mod.rs

@@ -16,15 +16,6 @@
 
 //! Ethereum rpc interface implementation.
 
-macro_rules! take_weak {
-	($weak: expr) => {
-		match $weak.upgrade() {
-			Some(arc) => arc,
-			None => return Err(Error::internal_error())
-		}
-	}
-}
-
 mod eth;
 mod eth_filter;
 mod net;
@@ -39,6 +30,8 @@ mod rpc;
 mod traces;
 mod web3;
 
+pub mod light;
+
 pub use self::web3::Web3Client;
 pub use self::eth::{EthClient, EthClientOptions};
 pub use self::eth_filter::EthFilterClient;

rpc/src/v1/impls/personal.rs

@@ -18,48 +18,37 @@
 use std::sync::{Arc, Weak};
 
 use ethcore::account_provider::AccountProvider;
-use ethcore::client::MiningBlockChainClient;
+use ethcore::transaction::PendingTransaction;
-use ethcore::miner::MinerService;
-use util::{Address, U128, Uint};
 
-use futures::{self, Future, BoxFuture};
+use util::{Address, U128, Uint, ToPretty};
+
+use futures::{future, Future, BoxFuture};
 use jsonrpc_core::Error;
 use v1::helpers::errors;
-use v1::helpers::dispatch::{self, sign_and_dispatch};
+use v1::helpers::dispatch::{Dispatcher, SignWith};
 use v1::traits::Personal;
 use v1::types::{H160 as RpcH160, H256 as RpcH256, U128 as RpcU128, TransactionRequest};
 use v1::metadata::Metadata;
 
 /// Account management (personal) rpc implementation.
-pub struct PersonalClient<C, M> where
+pub struct PersonalClient<D: Dispatcher> {
-	C: MiningBlockChainClient,
-	M: MinerService,
-{
 	accounts: Weak<AccountProvider>,
-	client: Weak<C>,
+	dispatcher: D,
-	miner: Weak<M>,
 	allow_perm_unlock: bool,
 }
 
-impl<C, M> PersonalClient<C, M> where
+impl<D: Dispatcher> PersonalClient<D> {
-	C: MiningBlockChainClient,
-	M: MinerService,
-{
 	/// Creates new PersonalClient
-	pub fn new(store: &Arc<AccountProvider>, client: &Arc<C>, miner: &Arc<M>, allow_perm_unlock: bool) -> Self {
+	pub fn new(store: &Arc<AccountProvider>, dispatcher: D, allow_perm_unlock: bool) -> Self {
 		PersonalClient {
 			accounts: Arc::downgrade(store),
-			client: Arc::downgrade(client),
+			dispatcher: dispatcher,
-			miner: Arc::downgrade(miner),
 			allow_perm_unlock: allow_perm_unlock,
 		}
 	}
 }
 
-impl<C, M> Personal for PersonalClient<C, M> where
+impl<D: Dispatcher + 'static> Personal for PersonalClient<D> {
-	C: MiningBlockChainClient + 'static,
-	M: MinerService + 'static,
-{
 	type Metadata = Metadata;
 
 	fn accounts(&self) -> Result<Vec<RpcH160>, Error> {
@@ -106,28 +95,36 @@ impl<C, M> Personal for PersonalClient<C, M> where
 	}
 
 	fn send_transaction(&self, meta: Metadata, request: TransactionRequest, password: String) -> BoxFuture<RpcH256, Error> {
-		let sign_and_send = move || {
+		let dispatcher = self.dispatcher.clone();
-			let client = take_weak!(self.client);
+		let accounts = take_weakf!(self.accounts);
-			let miner = take_weak!(self.miner);
-			let accounts = take_weak!(self.accounts);
 
-			let default_account = match request.from {
+		let default = match request.from.as_ref() {
-				Some(ref account) => account.clone().into(),
+			Some(account) => Ok(account.clone().into()),
 			None => accounts
 				.default_address(meta.dapp_id.unwrap_or_default().into())
-					.map_err(|e| errors::account("Cannot find default account.", e))?,
+				.map_err(|e| errors::account("Cannot find default account.", e)),
 		};
 
-			let request = dispatch::fill_optional_fields(request.into(), default_account, &*client, &*miner);
+		let default = match default {
-			sign_and_dispatch(
+			Ok(default) => default,
-				&*client,
+			Err(e) => return future::err(e).boxed(),
-				&*miner,
-				&*accounts,
-				request,
-				dispatch::SignWith::Password(password)
-			).map(|v| v.into_value().into())
 		};
 
-		futures::done(sign_and_send()).boxed()
+		dispatcher.fill_optional_fields(request.into(), default)
+			.and_then(move |filled| {
+				let condition = filled.condition.clone().map(Into::into);
+				dispatcher.sign(&accounts, filled, SignWith::Password(password))
+					.map(|tx| tx.into_value())
+					.map(move |tx| PendingTransaction::new(tx, condition))
+					.map(move |tx| (tx, dispatcher))
+			})
+			.and_then(|(pending_tx, dispatcher)| {
+				let network_id = pending_tx.network_id();
+				trace!(target: "miner", "send_transaction: dispatching tx: {} for network ID {:?}",
+					::rlp::encode(&*pending_tx).to_vec().pretty(), network_id);
+
+				dispatcher.dispatch_transaction(pending_tx).map(Into::into)
+			})
+			.boxed()
 	}
 }

rpc/src/v1/impls/signer.rs

@@ -20,49 +20,53 @@ use std::sync::{Arc, Weak};
 
 use rlp::{UntrustedRlp, View};
 use ethcore::account_provider::AccountProvider;
-use ethcore::client::MiningBlockChainClient;
 use ethcore::transaction::{SignedTransaction, PendingTransaction};
-use ethcore::miner::MinerService;
+use futures::{future, BoxFuture, Future, IntoFuture};
 
 use jsonrpc_core::Error;
 use v1::helpers::{errors, SignerService, SigningQueue, ConfirmationPayload};
-use v1::helpers::dispatch::{self, dispatch_transaction, WithToken};
+use v1::helpers::dispatch::{self, Dispatcher, WithToken};
 use v1::traits::Signer;
 use v1::types::{TransactionModification, ConfirmationRequest, ConfirmationResponse, ConfirmationResponseWithToken, U256, Bytes};
 
 /// Transactions confirmation (personal) rpc implementation.
-pub struct SignerClient<C, M> where C: MiningBlockChainClient, M: MinerService {
+pub struct SignerClient<D: Dispatcher> {
 	signer: Weak<SignerService>,
 	accounts: Weak<AccountProvider>,
-	client: Weak<C>,
+	dispatcher: D
-	miner: Weak<M>,
 }
 
-impl<C: 'static, M: 'static> SignerClient<C, M> where C: MiningBlockChainClient, M: MinerService {
+impl<D: Dispatcher + 'static> SignerClient<D> {
 
 	/// Create new instance of signer client.
 	pub fn new(
 		store: &Arc<AccountProvider>,
-		client: &Arc<C>,
+		dispatcher: D,
-		miner: &Arc<M>,
 		signer: &Arc<SignerService>,
 	) -> Self {
 		SignerClient {
 			signer: Arc::downgrade(signer),
 			accounts: Arc::downgrade(store),
-			client: Arc::downgrade(client),
+			dispatcher: dispatcher,
-			miner: Arc::downgrade(miner),
 		}
 	}
 
-	fn confirm_internal<F>(&self, id: U256, modification: TransactionModification, f: F) -> Result<WithToken<ConfirmationResponse>, Error> where
+	fn confirm_internal<F, T>(&self, id: U256, modification: TransactionModification, f: F) -> BoxFuture<WithToken<ConfirmationResponse>, Error> where
-		F: FnOnce(&C, &M, &AccountProvider, ConfirmationPayload) -> Result<WithToken<ConfirmationResponse>, Error>,
+		F: FnOnce(D, &AccountProvider, ConfirmationPayload) -> T,
+		T: IntoFuture<Item=WithToken<ConfirmationResponse>, Error=Error>,
+		T::Future: Send + 'static
 	{
 		let id = id.into();
-		let accounts = take_weak!(self.accounts);
+		let dispatcher = self.dispatcher.clone();
-		let signer = take_weak!(self.signer);
+
-		let client = take_weak!(self.client);
+		let setup = || {
-		let miner = take_weak!(self.miner);
+			Ok((take_weak!(self.accounts), take_weak!(self.signer)))
+		};
+
+		let (accounts, signer) = match setup() {
+			Ok(x) => x,
+			Err(e) => return future::err(e).boxed(),
+		};
 
 		signer.peek(&id).map(|confirmation| {
 			let mut payload = confirmation.payload.clone();
@@ -83,17 +87,21 @@ impl<C: 'static, M: 'static> SignerClient<C, M> where C: MiningBlockChainClient,
 					request.condition = condition.clone().map(Into::into);
 				}
 			}
-			let result = f(&*client, &*miner, &*accounts, payload);
+			let fut = f(dispatcher, &*accounts, payload);
+			fut.into_future().then(move |result| {
 				// Execute
 				if let Ok(ref response) = result {
 					signer.request_confirmed(id, Ok((*response).clone()));
 				}
+
 				result
-		}).unwrap_or_else(|| Err(errors::invalid_params("Unknown RequestID", id)))
+			}).boxed()
+		})
+		.unwrap_or_else(|| future::err(errors::invalid_params("Unknown RequestID", id)).boxed())
 	}
 }
 
-impl<C: 'static, M: 'static> Signer for SignerClient<C, M> where C: MiningBlockChainClient, M: MinerService {
+impl<D: Dispatcher + 'static> Signer for SignerClient<D> {
 
 	fn requests_to_confirm(&self) -> Result<Vec<ConfirmationRequest>, Error> {
 		let signer = take_weak!(self.signer);
@@ -107,29 +115,31 @@ impl<C: 'static, M: 'static> Signer for SignerClient<C, M> where C: MiningBlockC
 
 	// TODO [ToDr] TransactionModification is redundant for some calls
 	// might be better to replace it in future
-	fn confirm_request(&self, id: U256, modification: TransactionModification, pass: String) -> Result<ConfirmationResponse, Error> {
+	fn confirm_request(&self, id: U256, modification: TransactionModification, pass: String)
-		self.confirm_internal(id, modification, move |client, miner, accounts, payload| {
+		-> BoxFuture<ConfirmationResponse, Error>
-			dispatch::execute(client, miner, accounts, payload, dispatch::SignWith::Password(pass))
+	{
-		}).map(|v| v.into_value())
+		self.confirm_internal(id, modification, move |dis, accounts, payload| {
+			dispatch::execute(dis, accounts, payload, dispatch::SignWith::Password(pass))
+		}).map(|v| v.into_value()).boxed()
 	}
 
-	fn confirm_request_with_token(&self, id: U256, modification: TransactionModification, token: String) -> Result<ConfirmationResponseWithToken, Error> {
+	fn confirm_request_with_token(&self, id: U256, modification: TransactionModification, token: String)
-		self.confirm_internal(id, modification, move |client, miner, accounts, payload| {
+		-> BoxFuture<ConfirmationResponseWithToken, Error>
-			dispatch::execute(client, miner, accounts, payload, dispatch::SignWith::Token(token))
+	{
+		self.confirm_internal(id, modification, move |dis, accounts, payload| {
+			dispatch::execute(dis, accounts, payload, dispatch::SignWith::Token(token))
 		}).and_then(|v| match v {
 			WithToken::No(_) => Err(errors::internal("Unexpected response without token.", "")),
 			WithToken::Yes(response, token) => Ok(ConfirmationResponseWithToken {
 				result: response,
 				token: token,
 			}),
-		})
+		}).boxed()
 	}
 
 	fn confirm_request_raw(&self, id: U256, bytes: Bytes) -> Result<ConfirmationResponse, Error> {
 		let id = id.into();
 		let signer = take_weak!(self.signer);
-		let client = take_weak!(self.client);
-		let miner = take_weak!(self.miner);
 
 		signer.peek(&id).map(|confirmation| {
 			let result = match confirmation.payload {
@@ -150,7 +160,7 @@ impl<C: 'static, M: 'static> Signer for SignerClient<C, M> where C: MiningBlockC
 					// Dispatch if everything is ok
 					if sender_matches && data_matches && value_matches && nonce_matches {
 						let pending_transaction = PendingTransaction::new(signed_transaction, request.condition.map(Into::into));
-						dispatch_transaction(&*client, &*miner, pending_transaction)
+						self.dispatcher.dispatch_transaction(pending_transaction)
 							.map(Into::into)
 							.map(ConfirmationResponse::SendTransaction)
 					} else {

rpc/src/v1/impls/signing.rs

@@ -21,16 +21,15 @@ use transient_hashmap::TransientHashMap;
 use util::{U256, Mutex};
 
 use ethcore::account_provider::AccountProvider;
-use ethcore::miner::MinerService;
-use ethcore::client::MiningBlockChainClient;
 
-use futures::{self, BoxFuture, Future};
+use futures::{self, future, BoxFuture, Future};
 use jsonrpc_core::Error;
 use v1::helpers::{
-	errors, dispatch,
+	errors,
 	DefaultAccount,
-	SigningQueue, ConfirmationPromise, ConfirmationResult, ConfirmationPayload, SignerService
+	SigningQueue, ConfirmationPromise, ConfirmationResult, SignerService
 };
+use v1::helpers::dispatch::{self, Dispatcher};
 use v1::metadata::Metadata;
 use v1::traits::{EthSigning, ParitySigning};
 use v1::types::{
@@ -50,31 +49,14 @@ enum DispatchResult {
 }
 
 /// Implementation of functions that require signing when no trusted signer is used.
-pub struct SigningQueueClient<C, M> where C: MiningBlockChainClient, M: MinerService {
+pub struct SigningQueueClient<D> {
 	signer: Weak<SignerService>,
 	accounts: Weak<AccountProvider>,
-	client: Weak<C>,
+	dispatcher: D,
-	miner: Weak<M>,
+	pending: Arc<Mutex<TransientHashMap<U256, ConfirmationPromise>>>,
-
-	pending: Mutex<TransientHashMap<U256, ConfirmationPromise>>,
 }
 
-impl<C, M> SigningQueueClient<C, M> where
+fn handle_dispatch<OnResponse>(res: Result<DispatchResult, Error>, on_response: OnResponse)
-	C: MiningBlockChainClient,
-	M: MinerService,
-{
-	/// Creates a new signing queue client given shared signing queue.
-	pub fn new(signer: &Arc<SignerService>, client: &Arc<C>, miner: &Arc<M>, accounts: &Arc<AccountProvider>) -> Self {
-		SigningQueueClient {
-			signer: Arc::downgrade(signer),
-			accounts: Arc::downgrade(accounts),
-			client: Arc::downgrade(client),
-			miner: Arc::downgrade(miner),
-			pending: Mutex::new(TransientHashMap::new(MAX_PENDING_DURATION)),
-		}
-	}
-
-	fn handle_dispatch<OnResponse>(&self, res: Result<DispatchResult, Error>, on_response: OnResponse)
 	where OnResponse: FnOnce(Result<RpcConfirmationResponse, Error>) + Send + 'static
 {
 	match res {
@@ -88,67 +70,75 @@ impl<C, M> SigningQueueClient<C, M> where
 	}
 }
 
-	fn add_to_queue(&self, payload: ConfirmationPayload) -> Result<DispatchResult, Error> {
+impl<D: Dispatcher + 'static> SigningQueueClient<D> {
-		let client = take_weak!(self.client);
+	/// Creates a new signing queue client given shared signing queue.
-		let miner = take_weak!(self.miner);
+	pub fn new(signer: &Arc<SignerService>, dispatcher: D, accounts: &Arc<AccountProvider>) -> Self {
-		let accounts = take_weak!(self.accounts);
+		SigningQueueClient {
-
+			signer: Arc::downgrade(signer),
-		let sender = payload.sender();
+			accounts: Arc::downgrade(accounts),
-		if accounts.is_unlocked(sender) {
+			dispatcher: dispatcher,
-			return dispatch::execute(&*client, &*miner, &*accounts, payload, dispatch::SignWith::Nothing)
+			pending: Arc::new(Mutex::new(TransientHashMap::new(MAX_PENDING_DURATION))),
-				.map(|v| v.into_value())
+		}
-				.map(DispatchResult::Value);
 	}
 
-		take_weak!(self.signer).add_request(payload)
+	fn dispatch(&self, payload: RpcConfirmationPayload, default_account: DefaultAccount) -> BoxFuture<DispatchResult, Error> {
-			.map(DispatchResult::Promise)
+		let accounts = take_weakf!(self.accounts);
-			.map_err(|_| errors::request_rejected_limit())
-	}
-
-	fn dispatch(&self, payload: RpcConfirmationPayload, default_account: DefaultAccount) -> Result<DispatchResult, Error> {
-		let client = take_weak!(self.client);
-		let miner = take_weak!(self.miner);
-
 		let default_account = match default_account {
 			DefaultAccount::Provided(acc) => acc,
-			DefaultAccount::ForDapp(dapp) => take_weak!(self.accounts).default_address(dapp).ok().unwrap_or_default(),
+			DefaultAccount::ForDapp(dapp) => accounts.default_address(dapp).ok().unwrap_or_default(),
 		};
-		let payload = dispatch::from_rpc(payload, default_account, &*client, &*miner);
+
-		self.add_to_queue(payload)
+		let dispatcher = self.dispatcher.clone();
+		let signer = take_weakf!(self.signer);
+		dispatch::from_rpc(payload, default_account, &dispatcher)
+			.and_then(move |payload| {
+				let sender = payload.sender();
+				if accounts.is_unlocked(sender) {
+					dispatch::execute(dispatcher, &accounts, payload, dispatch::SignWith::Nothing)
+						.map(|v| v.into_value())
+						.map(DispatchResult::Value)
+						.boxed()
+				} else {
+					future::done(
+						signer.add_request(payload)
+							.map(DispatchResult::Promise)
+							.map_err(|_| errors::request_rejected_limit())
+					).boxed()
+				}
+			})
+			.boxed()
 	}
 }
 
-impl<C: 'static, M: 'static> ParitySigning for SigningQueueClient<C, M> where
+impl<D: Dispatcher + 'static> ParitySigning for SigningQueueClient<D> {
-	C: MiningBlockChainClient,
-	M: MinerService,
-{
 	type Metadata = Metadata;
 
-	fn post_sign(&self, address: RpcH160, data: RpcBytes) -> Result<RpcEither<RpcU256, RpcConfirmationResponse>, Error> {
+	fn post_sign(&self, address: RpcH160, data: RpcBytes) -> BoxFuture<RpcEither<RpcU256, RpcConfirmationResponse>, Error> {
+		let pending = self.pending.clone();
 		self.dispatch(RpcConfirmationPayload::Signature((address.clone(), data).into()), DefaultAccount::Provided(address.into()))
-			.map(|result| match result {
+			.map(move |result| match result {
 				DispatchResult::Value(v) => RpcEither::Or(v),
 				DispatchResult::Promise(promise) => {
 					let id = promise.id();
-					self.pending.lock().insert(id, promise);
+					pending.lock().insert(id, promise);
 					RpcEither::Either(id.into())
 				},
 			})
+			.boxed()
 	}
 
 	fn post_transaction(&self, meta: Metadata, request: RpcTransactionRequest) -> BoxFuture<RpcEither<RpcU256, RpcConfirmationResponse>, Error> {
-		let post_transaction = move || {
+		let pending = self.pending.clone();
 		self.dispatch(RpcConfirmationPayload::SendTransaction(request), meta.into())
-				.map(|result| match result {
+			.map(move |result| match result {
 				DispatchResult::Value(v) => RpcEither::Or(v),
 				DispatchResult::Promise(promise) => {
 					let id = promise.id();
-						self.pending.lock().insert(id, promise);
+					pending.lock().insert(id, promise);
 					RpcEither::Either(id.into())
 				},
 			})
-		};
+			.boxed()
-		futures::done(post_transaction()).boxed()
 	}
 
 	fn check_request(&self, id: RpcU256) -> Result<Option<RpcConfirmationResponse>, Error> {
@@ -170,8 +160,11 @@ impl<C: 'static, M: 'static> ParitySigning for SigningQueueClient<C, M> where
 		let res = self.dispatch(RpcConfirmationPayload::Decrypt((address.clone(), data).into()), address.into());
 
 		let (ready, p) = futures::oneshot();
-		// TODO [todr] typed handle_dispatch
+
-		self.handle_dispatch(res, |response| {
+		// when dispatch is complete
+		res.then(move |res| {
+			// register callback via the oneshot sender.
+			handle_dispatch(res, move |response| {
 				match response {
 					Ok(RpcConfirmationResponse::Decrypt(data)) => ready.complete(Ok(data)),
 					Err(e) => ready.complete(Err(e)),
@@ -179,36 +172,40 @@ impl<C: 'static, M: 'static> ParitySigning for SigningQueueClient<C, M> where
 				}
 			});
 
-		p.then(|result| futures::done(result.expect("Ready is never dropped nor canceled."))).boxed()
+			// and wait for that to resolve.
+			p.then(|result| futures::done(result.expect("Ready is never dropped nor canceled.")))
+		}).boxed()
 	}
 }
 
-impl<C: 'static, M: 'static> EthSigning for SigningQueueClient<C, M> where
+impl<D: Dispatcher + 'static> EthSigning for SigningQueueClient<D> {
-	C: MiningBlockChainClient,
-	M: MinerService,
-{
 	type Metadata = Metadata;
 
 	fn sign(&self, address: RpcH160, data: RpcBytes) -> BoxFuture<RpcH520, Error> {
 		let res = self.dispatch(RpcConfirmationPayload::Signature((address.clone(), data).into()), address.into());
 
 		let (ready, p) = futures::oneshot();
-		self.handle_dispatch(res, |response| {
+
+		res.then(move |res| {
+			handle_dispatch(res, move |response| {
 				match response {
-				Ok(RpcConfirmationResponse::Signature(signature)) => ready.complete(Ok(signature)),
+					Ok(RpcConfirmationResponse::Signature(sig)) => ready.complete(Ok(sig)),
 					Err(e) => ready.complete(Err(e)),
 					e => ready.complete(Err(errors::internal("Unexpected result.", e))),
 				}
 			});
 
-		p.then(|result| futures::done(result.expect("Ready is never dropped nor canceled."))).boxed()
+			p.then(|result| futures::done(result.expect("Ready is never dropped nor canceled.")))
+		}).boxed()
 	}
 
 	fn send_transaction(&self, meta: Metadata, request: RpcTransactionRequest) -> BoxFuture<RpcH256, Error> {
 		let res = self.dispatch(RpcConfirmationPayload::SendTransaction(request), meta.into());
 
 		let (ready, p) = futures::oneshot();
-		self.handle_dispatch(res, |response| {
+
+		res.then(move |res| {
+			handle_dispatch(res, move |response| {
 				match response {
 					Ok(RpcConfirmationResponse::SendTransaction(hash)) => ready.complete(Ok(hash)),
 					Err(e) => ready.complete(Err(e)),
@@ -216,14 +213,17 @@ impl<C: 'static, M: 'static> EthSigning for SigningQueueClient<C, M> where
 				}
 			});
 
-		p.then(|result| futures::done(result.expect("Ready is never dropped nor canceled."))).boxed()
+			p.then(|result| futures::done(result.expect("Ready is never dropped nor canceled.")))
+		}).boxed()
 	}
 
 	fn sign_transaction(&self, meta: Metadata, request: RpcTransactionRequest) -> BoxFuture<RpcRichRawTransaction, Error> {
 		let res = self.dispatch(RpcConfirmationPayload::SignTransaction(request), meta.into());
 
 		let (ready, p) = futures::oneshot();
-		self.handle_dispatch(res, |response| {
+
+		res.then(move |res| {
+			handle_dispatch(res, move |response| {
 				match response {
 					Ok(RpcConfirmationResponse::SignTransaction(tx)) => ready.complete(Ok(tx)),
 					Err(e) => ready.complete(Err(e)),
@@ -231,6 +231,7 @@ impl<C: 'static, M: 'static> EthSigning for SigningQueueClient<C, M> where
 				}
 			});
 
-		p.then(|result| futures::done(result.expect("Ready is never dropped nor canceled."))).boxed()
+			p.then(|result| futures::done(result.expect("Ready is never dropped nor canceled.")))
+		}).boxed()
 	}
 }

rpc/src/v1/impls/signing_unsafe.rs

@@ -19,12 +19,11 @@
 use std::sync::{Arc, Weak};
 
 use ethcore::account_provider::AccountProvider;
-use ethcore::miner::MinerService;
-use ethcore::client::MiningBlockChainClient;
 
-use futures::{self, BoxFuture, Future};
+use futures::{future, BoxFuture, Future};
 use jsonrpc_core::Error;
-use v1::helpers::{errors, dispatch, DefaultAccount};
+use v1::helpers::{errors, DefaultAccount};
+use v1::helpers::dispatch::{self, Dispatcher};
 use v1::metadata::Metadata;
 use v1::traits::{EthSigning, ParitySigning};
 use v1::types::{
@@ -38,106 +37,93 @@ use v1::types::{
 };
 
 /// Implementation of functions that require signing when no trusted signer is used.
-pub struct SigningUnsafeClient<C, M> where
+pub struct SigningUnsafeClient<D> {
-	C: MiningBlockChainClient,
-	M: MinerService,
-{
 	accounts: Weak<AccountProvider>,
-	client: Weak<C>,
+	dispatcher: D,
-	miner: Weak<M>,
 }
 
-impl<C, M> SigningUnsafeClient<C, M> where
+impl<D: Dispatcher + 'static> SigningUnsafeClient<D> {
-	C: MiningBlockChainClient,
-	M: MinerService,
-{
-
 	/// Creates new SigningUnsafeClient.
-	pub fn new(client: &Arc<C>, accounts: &Arc<AccountProvider>, miner: &Arc<M>)
+	pub fn new(accounts: &Arc<AccountProvider>, dispatcher: D) -> Self {
-		-> Self {
 		SigningUnsafeClient {
-			client: Arc::downgrade(client),
-			miner: Arc::downgrade(miner),
 			accounts: Arc::downgrade(accounts),
+			dispatcher: dispatcher,
 		}
 	}
 
-	fn handle(&self, payload: RpcConfirmationPayload, account: DefaultAccount) -> Result<RpcConfirmationResponse, Error> {
+	fn handle(&self, payload: RpcConfirmationPayload, account: DefaultAccount) -> BoxFuture<RpcConfirmationResponse, Error> {
-		let client = take_weak!(self.client);
+		let accounts = take_weakf!(self.accounts);
-		let miner = take_weak!(self.miner);
+		let default = match account {
-		let accounts = take_weak!(self.accounts);
-
-		let default_account = match account {
 			DefaultAccount::Provided(acc) => acc,
 			DefaultAccount::ForDapp(dapp) => accounts.default_address(dapp).ok().unwrap_or_default(),
 		};
-		let payload = dispatch::from_rpc(payload, default_account, &*client, &*miner);
+
-		dispatch::execute(&*client, &*miner, &*accounts, payload, dispatch::SignWith::Nothing)
+		let dis = self.dispatcher.clone();
+		dispatch::from_rpc(payload, default, &dis)
+			.and_then(move |payload| {
+				dispatch::execute(dis, &accounts, payload, dispatch::SignWith::Nothing)
+			})
 			.map(|v| v.into_value())
+			.boxed()
 	}
 }
 
-impl<C: 'static, M: 'static> EthSigning for SigningUnsafeClient<C, M> where
+impl<D: Dispatcher + 'static> EthSigning for SigningUnsafeClient<D>
-	C: MiningBlockChainClient,
-	M: MinerService,
 {
 	type Metadata = Metadata;
 
 	fn sign(&self, address: RpcH160, data: RpcBytes) -> BoxFuture<RpcH520, Error> {
-		let result = match self.handle(RpcConfirmationPayload::Signature((address.clone(), data).into()), address.into()) {
+		self.handle(RpcConfirmationPayload::Signature((address.clone(), data).into()), address.into())
+			.then(|res| match res {
 				Ok(RpcConfirmationResponse::Signature(signature)) => Ok(signature),
 				Err(e) => Err(e),
 				e => Err(errors::internal("Unexpected result", e)),
-		};
+			})
-
+			.boxed()
-		futures::done(result).boxed()
 	}
 
 	fn send_transaction(&self, meta: Metadata, request: RpcTransactionRequest) -> BoxFuture<RpcH256, Error> {
-		let result = match self.handle(RpcConfirmationPayload::SendTransaction(request), meta.into()) {
+		self.handle(RpcConfirmationPayload::SendTransaction(request), meta.into())
+			.then(|res| match res {
 				Ok(RpcConfirmationResponse::SendTransaction(hash)) => Ok(hash),
 				Err(e) => Err(e),
 				e => Err(errors::internal("Unexpected result", e)),
-		};
+			})
-
+			.boxed()
-		futures::done(result).boxed()
 	}
 
 	fn sign_transaction(&self, meta: Metadata, request: RpcTransactionRequest) -> BoxFuture<RpcRichRawTransaction, Error> {
-		let result = match self.handle(RpcConfirmationPayload::SignTransaction(request), meta.into()) {
+		self.handle(RpcConfirmationPayload::SignTransaction(request), meta.into())
+			.then(|res| match res {
 				Ok(RpcConfirmationResponse::SignTransaction(tx)) => Ok(tx),
 				Err(e) => Err(e),
 				e => Err(errors::internal("Unexpected result", e)),
-		};
+			})
-
+			.boxed()
-		futures::done(result).boxed()
 	}
 }
 
-impl<C: 'static, M: 'static> ParitySigning for SigningUnsafeClient<C, M> where
+impl<D: Dispatcher + 'static> ParitySigning for SigningUnsafeClient<D> {
-	C: MiningBlockChainClient,
-	M: MinerService,
-{
 	type Metadata = Metadata;
 
 	fn decrypt_message(&self, address: RpcH160, data: RpcBytes) -> BoxFuture<RpcBytes, Error> {
-		let result = match self.handle(RpcConfirmationPayload::Decrypt((address.clone(), data).into()), address.into()) {
+		self.handle(RpcConfirmationPayload::Decrypt((address.clone(), data).into()), address.into())
+			.then(|res| match res {
 				Ok(RpcConfirmationResponse::Decrypt(data)) => Ok(data),
 				Err(e) => Err(e),
 				e => Err(errors::internal("Unexpected result", e)),
-		};
+			})
-
+			.boxed()
-		futures::done(result).boxed()
 	}
 
-	fn post_sign(&self, _: RpcH160, _: RpcBytes) -> Result<RpcEither<RpcU256, RpcConfirmationResponse>, Error> {
+	fn post_sign(&self, _: RpcH160, _: RpcBytes) -> BoxFuture<RpcEither<RpcU256, RpcConfirmationResponse>, Error> {
 		// We don't support this in non-signer mode.
-		Err(errors::signer_disabled())
+		future::err(errors::signer_disabled()).boxed()
 	}
 
 	fn post_transaction(&self, _: Metadata, _: RpcTransactionRequest) -> BoxFuture<RpcEither<RpcU256, RpcConfirmationResponse>, Error> {
 		// We don't support this in non-signer mode.
-		futures::done(Err(errors::signer_disabled())).boxed()
+		future::err((errors::signer_disabled())).boxed()
 	}
 
 	fn check_request(&self, _: RpcU256) -> Result<Option<RpcConfirmationResponse>, Error> {

rpc/src/v1/mod.rs

@@ -18,6 +18,37 @@
 //!
 //! Compliant with ethereum rpc.
 
+// Upgrade a weak pointer, returning an error on failure.
+macro_rules! take_weak {
+	($weak: expr) => {
+		match $weak.upgrade() {
+			Some(arc) => arc,
+			None => return Err(Error::internal_error()),
+		}
+	}
+}
+
+// Upgrade a weak pointer, returning an error leaf-future on failure.
+macro_rules! take_weakf {
+	($weak: expr) => {
+		match $weak.upgrade() {
+			Some(arc) => arc,
+			None => return ::futures::future::err(Error::internal_error()).boxed(),
+		}
+	}
+}
+
+// short for "try_boxfuture"
+// unwrap a result, returning a BoxFuture<_, Err> on failure.
+macro_rules! try_bf {
+	($res: expr) => {
+		match $res {
+			Ok(val) => val,
+			Err(e) => return ::futures::future::err(e.into()).boxed(),
+		}
+	}
+}
+
 #[macro_use]
 mod helpers;
 mod impls;
@@ -29,5 +60,5 @@ pub mod types;
 
 pub use self::traits::{Web3, Eth, EthFilter, EthSigning, Net, Parity, ParityAccounts, ParitySet, ParitySigning, Signer, Personal, Traces, Rpc};
 pub use self::impls::*;
-pub use self::helpers::{SigningQueue, SignerService, ConfirmationsQueue, NetworkSettings, block_import, informant};
+pub use self::helpers::{SigningQueue, SignerService, ConfirmationsQueue, NetworkSettings, block_import, informant, dispatch};
 pub use self::metadata::{Metadata, Origin};

rpc/src/v1/tests/eth.rs

@@ -33,6 +33,7 @@ use util::{U256, H256, Uint, Address, Hashable};
 
 use jsonrpc_core::IoHandler;
 use v1::impls::{EthClient, SigningUnsafeClient};
+use v1::helpers::dispatch::FullDispatcher;
 use v1::metadata::Metadata;
 use v1::tests::helpers::{TestSnapshotService, TestSyncProvider, Config};
 use v1::traits::eth::Eth;
@@ -141,10 +142,11 @@ impl EthTester {
 			&external_miner,
 			Default::default(),
 		);
+
+		let dispatcher = FullDispatcher::new(Arc::downgrade(&client), Arc::downgrade(&miner_service));
 		let eth_sign = SigningUnsafeClient::new(
-			&client,
 			&account_provider,
-			&miner_service
+			dispatcher,
 		);
 
 		let mut handler = IoHandler::default();

rpc/src/v1/tests/mocked/eth.rs

@@ -34,6 +34,7 @@ use ethsync::SyncState;
 
 use jsonrpc_core::IoHandler;
 use v1::{Eth, EthClient, EthClientOptions, EthFilter, EthFilterClient, EthSigning, SigningUnsafeClient};
+use v1::helpers::dispatch::FullDispatcher;
 use v1::tests::helpers::{TestSyncProvider, Config, TestMinerService, TestSnapshotService};
 use v1::metadata::Metadata;
 
@@ -88,7 +89,9 @@ impl EthTester {
 		let external_miner = Arc::new(ExternalMiner::new(hashrates.clone()));
 		let eth = EthClient::new(&client, &snapshot, &sync, &ap, &miner, &external_miner, options).to_delegate();
 		let filter = EthFilterClient::new(&client, &miner).to_delegate();
-		let sign = SigningUnsafeClient::new(&client, &ap, &miner).to_delegate();
+
+		let dispatcher = FullDispatcher::new(Arc::downgrade(&client), Arc::downgrade(&miner));
+		let sign = SigningUnsafeClient::new(&ap, dispatcher).to_delegate();
 		let mut io: IoHandler<Metadata> = IoHandler::default();
 		io.extend_with(eth);
 		io.extend_with(sign);

rpc/src/v1/tests/mocked/personal.rs

@@ -16,13 +16,16 @@
 
 use std::sync::Arc;
 use std::str::FromStr;
-use jsonrpc_core::IoHandler;
+
-use util::{U256, Uint, Address};
 use ethcore::account_provider::AccountProvider;
-use v1::{PersonalClient, Personal, Metadata};
-use v1::tests::helpers::TestMinerService;
 use ethcore::client::TestBlockChainClient;
 use ethcore::transaction::{Action, Transaction};
+use jsonrpc_core::IoHandler;
+use util::{U256, Uint, Address};
+
+use v1::{PersonalClient, Personal, Metadata};
+use v1::helpers::dispatch::FullDispatcher;
+use v1::tests::helpers::TestMinerService;
 
 struct PersonalTester {
 	accounts: Arc<AccountProvider>,
@@ -50,7 +53,9 @@ fn setup() -> PersonalTester {
 	let accounts = accounts_provider();
 	let client = blockchain_client();
 	let miner = miner_service();
-	let personal = PersonalClient::new(&accounts, &client, &miner, false);
+
+	let dispatcher = FullDispatcher::new(Arc::downgrade(&client), Arc::downgrade(&miner));
+	let personal = PersonalClient::new(&accounts, dispatcher, false);
 
 	let mut io = IoHandler::default();
 	io.extend_with(personal.to_delegate());

rpc/src/v1/tests/mocked/signer.rs

@@ -29,6 +29,7 @@ use v1::{SignerClient, Signer};
 use v1::metadata::Metadata;
 use v1::tests::helpers::TestMinerService;
 use v1::helpers::{SigningQueue, SignerService, FilledTransactionRequest, ConfirmationPayload};
+use v1::helpers::dispatch::FullDispatcher;
 
 struct SignerTester {
 	signer: Arc<SignerService>,
@@ -59,8 +60,9 @@ fn signer_tester() -> SignerTester {
 	let client = blockchain_client();
 	let miner = miner_service();
 
+	let dispatcher = FullDispatcher::new(Arc::downgrade(&client), Arc::downgrade(&miner));
 	let mut io = IoHandler::default();
-	io.extend_with(SignerClient::new(&accounts, &client, &miner, &signer).to_delegate());
+	io.extend_with(SignerClient::new(&accounts, dispatcher, &signer).to_delegate());
 
 	SignerTester {
 		signer: signer,

rpc/src/v1/tests/mocked/signing.rs

@@ -16,13 +16,14 @@
 
 use std::str::FromStr;
 use std::sync::Arc;
+use std::time::Duration;
 use rlp;
 
 use jsonrpc_core::{IoHandler, Success};
 use v1::impls::SigningQueueClient;
 use v1::metadata::Metadata;
 use v1::traits::{EthSigning, ParitySigning, Parity};
-use v1::helpers::{SignerService, SigningQueue};
+use v1::helpers::{SignerService, SigningQueue, FullDispatcher};
 use v1::types::ConfirmationResponse;
 use v1::tests::helpers::TestMinerService;
 use v1::tests::mocked::parity;
@@ -51,9 +52,12 @@ impl Default for SigningTester {
 		let miner = Arc::new(TestMinerService::default());
 		let accounts = Arc::new(AccountProvider::transient_provider());
 		let mut io = IoHandler::default();
-		let rpc = SigningQueueClient::new(&signer, &client, &miner, &accounts);
+
+		let dispatcher = FullDispatcher::new(Arc::downgrade(&client), Arc::downgrade(&miner));
+
+		let rpc = SigningQueueClient::new(&signer, dispatcher.clone(), &accounts);
 		io.extend_with(EthSigning::to_delegate(rpc));
-		let rpc = SigningQueueClient::new(&signer, &client, &miner, &accounts);
+		let rpc = SigningQueueClient::new(&signer, dispatcher, &accounts);
 		io.extend_with(ParitySigning::to_delegate(rpc));
 
 		SigningTester {
@@ -91,9 +95,17 @@ fn should_add_sign_to_queue() {
 
 	// then
 	let promise = tester.io.handle_request(&request);
-	assert_eq!(tester.signer.requests().len(), 1);
+
+	// the future must be polled at least once before request is queued.
+	let signer = tester.signer.clone();
+	::std::thread::spawn(move || loop {
+		if signer.requests().len() == 1 {
 			// respond
-	tester.signer.request_confirmed(1.into(), Ok(ConfirmationResponse::Signature(0.into())));
+			signer.request_confirmed(1.into(), Ok(ConfirmationResponse::Signature(0.into())));
+			break
+		}
+		::std::thread::sleep(Duration::from_millis(100))
+	});
 
 	let res = promise.wait().unwrap();
 	assert_eq!(res, Some(response.to_owned()));
@@ -229,9 +241,17 @@ fn should_add_transaction_to_queue() {
 
 	// then
 	let promise = tester.io.handle_request(&request);
-	assert_eq!(tester.signer.requests().len(), 1);
+
+	// the future must be polled at least once before request is queued.
+	let signer = tester.signer.clone();
+	::std::thread::spawn(move || loop {
+		if signer.requests().len() == 1 {
 			// respond
-	tester.signer.request_confirmed(1.into(), Ok(ConfirmationResponse::SendTransaction(0.into())));
+			signer.request_confirmed(1.into(), Ok(ConfirmationResponse::SendTransaction(0.into())));
+			break
+		}
+		::std::thread::sleep(Duration::from_millis(100))
+	});
 
 	let res = promise.wait().unwrap();
 	assert_eq!(res, Some(response.to_owned()));
@@ -296,9 +316,17 @@ fn should_add_sign_transaction_to_the_queue() {
 	// then
 	tester.miner.last_nonces.write().insert(address.clone(), U256::zero());
 	let promise = tester.io.handle_request(&request);
-	assert_eq!(tester.signer.requests().len(), 1);
+
+	// the future must be polled at least once before request is queued.
+	let signer = tester.signer.clone();
+	::std::thread::spawn(move || loop {
+		if signer.requests().len() == 1 {
 			// respond
-	tester.signer.request_confirmed(1.into(), Ok(ConfirmationResponse::SignTransaction(t.into())));
+			signer.request_confirmed(1.into(), Ok(ConfirmationResponse::SignTransaction(t.into())));
+			break
+		}
+		::std::thread::sleep(Duration::from_millis(100))
+	});
 
 	let res = promise.wait().unwrap();
 	assert_eq!(res, Some(response.to_owned()));
@@ -391,12 +419,22 @@ fn should_add_decryption_to_the_queue() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x0102","id":1}"#;
 
+
 	// then
 	let promise = tester.io.handle_request(&request);
-	assert_eq!(tester.signer.requests().len(), 1);
-	// respond
-	tester.signer.request_confirmed(1.into(), Ok(ConfirmationResponse::Decrypt(vec![0x1, 0x2].into())));
 
+	// the future must be polled at least once before request is queued.
+	let signer = tester.signer.clone();
+	::std::thread::spawn(move || loop {
+		if signer.requests().len() == 1 {
+			// respond
+			signer.request_confirmed(1.into(), Ok(ConfirmationResponse::Decrypt(vec![0x1, 0x2].into())));
+			break
+		}
+		::std::thread::sleep(Duration::from_millis(100))
+	});
+
+	// check response: will deadlock if unsuccessful.
 	let res = promise.wait().unwrap();
 	assert_eq!(res, Some(response.to_owned()));
 }

rpc/src/v1/traits/eth.rs

@@ -62,44 +62,44 @@ build_rpc_trait! {
 		fn block_number(&self) -> Result<U256, Error>;
 
 		/// Returns balance of the given account.
-		#[rpc(name = "eth_getBalance")]
+		#[rpc(async, name = "eth_getBalance")]
-		fn balance(&self, H160, Trailing<BlockNumber>) -> Result<U256, Error>;
+		fn balance(&self, H160, Trailing<BlockNumber>) -> BoxFuture<U256, Error>;
 
 		/// Returns content of the storage at given address.
-		#[rpc(name = "eth_getStorageAt")]
+		#[rpc(async, name = "eth_getStorageAt")]
-		fn storage_at(&self, H160, U256, Trailing<BlockNumber>) -> Result<H256, Error>;
+		fn storage_at(&self, H160, U256, Trailing<BlockNumber>) -> BoxFuture<H256, Error>;
 
 		/// Returns block with given hash.
-		#[rpc(name = "eth_getBlockByHash")]
+		#[rpc(async, name = "eth_getBlockByHash")]
-		fn block_by_hash(&self, H256, bool) -> Result<Option<RichBlock>, Error>;
+		fn block_by_hash(&self, H256, bool) -> BoxFuture<Option<RichBlock>, Error>;
 
 		/// Returns block with given number.
-		#[rpc(name = "eth_getBlockByNumber")]
+		#[rpc(async, name = "eth_getBlockByNumber")]
-		fn block_by_number(&self, BlockNumber, bool) -> Result<Option<RichBlock>, Error>;
+		fn block_by_number(&self, BlockNumber, bool) -> BoxFuture<Option<RichBlock>, Error>;
 
 		/// Returns the number of transactions sent from given address at given time (block number).
-		#[rpc(name = "eth_getTransactionCount")]
+		#[rpc(async, name = "eth_getTransactionCount")]
-		fn transaction_count(&self, H160, Trailing<BlockNumber>) -> Result<U256, Error>;
+		fn transaction_count(&self, H160, Trailing<BlockNumber>) -> BoxFuture<U256, Error>;
 
 		/// Returns the number of transactions in a block with given hash.
-		#[rpc(name = "eth_getBlockTransactionCountByHash")]
+		#[rpc(async, name = "eth_getBlockTransactionCountByHash")]
-		fn block_transaction_count_by_hash(&self, H256) -> Result<Option<U256>, Error>;
+		fn block_transaction_count_by_hash(&self, H256) -> BoxFuture<Option<U256>, Error>;
 
 		/// Returns the number of transactions in a block with given block number.
-		#[rpc(name = "eth_getBlockTransactionCountByNumber")]
+		#[rpc(async, name = "eth_getBlockTransactionCountByNumber")]
-		fn block_transaction_count_by_number(&self, BlockNumber) -> Result<Option<U256>, Error>;
+		fn block_transaction_count_by_number(&self, BlockNumber) -> BoxFuture<Option<U256>, Error>;
 
 		/// Returns the number of uncles in a block with given hash.
-		#[rpc(name = "eth_getUncleCountByBlockHash")]
+		#[rpc(async, name = "eth_getUncleCountByBlockHash")]
-		fn block_uncles_count_by_hash(&self, H256) -> Result<Option<U256>, Error>;
+		fn block_uncles_count_by_hash(&self, H256) -> BoxFuture<Option<U256>, Error>;
 
 		/// Returns the number of uncles in a block with given block number.
-		#[rpc(name = "eth_getUncleCountByBlockNumber")]
+		#[rpc(async, name = "eth_getUncleCountByBlockNumber")]
-		fn block_uncles_count_by_number(&self, BlockNumber) -> Result<Option<U256>, Error>;
+		fn block_uncles_count_by_number(&self, BlockNumber) -> BoxFuture<Option<U256>, Error>;
 
 		/// Returns the code at given address at given time (block number).
-		#[rpc(name = "eth_getCode")]
+		#[rpc(async, name = "eth_getCode")]
-		fn code_at(&self, H160, Trailing<BlockNumber>) -> Result<Bytes, Error>;
+		fn code_at(&self, H160, Trailing<BlockNumber>) -> BoxFuture<Bytes, Error>;
 
 		/// Sends signed transaction, returning its hash.
 		#[rpc(name = "eth_sendRawTransaction")]

rpc/src/v1/traits/parity_signing.rs

@@ -27,8 +27,8 @@ build_rpc_trait! {
 
 		/// Posts sign request asynchronously.
 		/// Will return a confirmation ID for later use with check_transaction.
-		#[rpc(name = "parity_postSign")]
+		#[rpc(async, name = "parity_postSign")]
-		fn post_sign(&self, H160, Bytes) -> Result<Either<U256, ConfirmationResponse>, Error>;
+		fn post_sign(&self, H160, Bytes) -> BoxFuture<Either<U256, ConfirmationResponse>, Error>;
 
 		/// Posts transaction asynchronously.
 		/// Will return a transaction ID for later use with check_transaction.

rpc/src/v1/traits/signer.rs

@@ -16,6 +16,7 @@
 
 //! Parity Signer-related rpc interface.
 use jsonrpc_core::Error;
+use futures::BoxFuture;
 
 use v1::types::{U256, Bytes, TransactionModification, ConfirmationRequest, ConfirmationResponse, ConfirmationResponseWithToken};
 
@@ -28,12 +29,12 @@ build_rpc_trait! {
 		fn requests_to_confirm(&self) -> Result<Vec<ConfirmationRequest>, Error>;
 
 		/// Confirm specific request.
-		#[rpc(name = "signer_confirmRequest")]
+		#[rpc(async, name = "signer_confirmRequest")]
-		fn confirm_request(&self, U256, TransactionModification, String) -> Result<ConfirmationResponse, Error>;
+		fn confirm_request(&self, U256, TransactionModification, String) -> BoxFuture<ConfirmationResponse, Error>;
 
 		/// Confirm specific request with token.
-		#[rpc(name = "signer_confirmRequestWithToken")]
+		#[rpc(async, name = "signer_confirmRequestWithToken")]
-		fn confirm_request_with_token(&self, U256, TransactionModification, String) -> Result<ConfirmationResponseWithToken, Error>;
+		fn confirm_request_with_token(&self, U256, TransactionModification, String) -> BoxFuture<ConfirmationResponseWithToken, Error>;
 
 		/// Confirm specific request with already signed data.
 		#[rpc(name = "signer_confirmRequestRaw")]

rpc/src/v1/types/block.rs

@@ -83,7 +83,7 @@ pub struct Block {
 	pub difficulty: U256,
 	/// Total difficulty
 	#[serde(rename="totalDifficulty")]
-	pub total_difficulty: U256,
+	pub total_difficulty: Option<U256>,
 	/// Seal fields
 	#[serde(rename="sealFields")]
 	pub seal_fields: Vec<Bytes>,
@@ -164,7 +164,7 @@ mod tests {
 			logs_bloom: H2048::default(),
 			timestamp: U256::default(),
 			difficulty: U256::default(),
-			total_difficulty: U256::default(),
+			total_difficulty: Some(U256::default()),
 			seal_fields: vec![Bytes::default(), Bytes::default()],
 			uncles: vec![],
 			transactions: BlockTransactions::Hashes(vec![].into()),

sync/src/api.rs

@@ -43,7 +43,7 @@ pub const WARP_SYNC_PROTOCOL_ID: ProtocolId = *b"par";
 /// Ethereum sync protocol
 pub const ETH_PROTOCOL: ProtocolId = *b"eth";
 /// Ethereum light protocol
-pub const LES_PROTOCOL: ProtocolId = *b"les";
+pub const LIGHT_PROTOCOL: ProtocolId = *b"plp";
 
 /// Sync configuration
 #[derive(Debug, Clone, Copy)]
@@ -56,7 +56,7 @@ pub struct SyncConfig {
 	pub network_id: u64,
 	/// Main "eth" subprotocol name.
 	pub subprotocol_name: [u8; 3],
-	/// Light "les" subprotocol name.
+	/// Light subprotocol name.
 	pub light_subprotocol_name: [u8; 3],
 	/// Fork block to check
 	pub fork_block: Option<(BlockNumber, H256)>,
@@ -73,7 +73,7 @@ impl Default for SyncConfig {
 			download_old_blocks: true,
 			network_id: 1,
 			subprotocol_name: ETH_PROTOCOL,
-			light_subprotocol_name: LES_PROTOCOL,
+			light_subprotocol_name: LIGHT_PROTOCOL,
 			fork_block: None,
 			warp_sync: false,
 			serve_light: false,
@@ -674,6 +674,16 @@ impl LightSync {
 			subprotocol_name: params.subprotocol_name,
 		})
 	}
+
+	/// Execute a closure with a protocol context.
+	pub fn with_context<F, T>(&self, f: F) -> Option<T>
+		where F: FnOnce(&::light::net::BasicContext) -> T
+	{
+		self.network.with_context_eval(
+			self.subprotocol_name,
+			move |ctx| self.proto.with_context(ctx, f),
+		)
+	}
 }
 
 impl ManageNetwork for LightSync {

sync/src/light_sync/tests/mod.rs

@@ -28,7 +28,7 @@ fn basic_sync() {
 
 	net.sync();
 
-	assert!(net.peer(0).light_chain().get_header(BlockId::Number(6000)).is_some());
+	assert!(net.peer(0).light_chain().block_header(BlockId::Number(6000)).is_some());
 }
 
 #[test]
@@ -49,15 +49,15 @@ fn fork_post_cht() {
 		let _  = light_chain.import_header(header);
 		light_chain.flush_queue();
 		light_chain.import_verified();
-		assert!(light_chain.get_header(id).is_some());
+		assert!(light_chain.block_header(id).is_some());
 	}
 
 	net.sync();
 
 	for id in (0..CHAIN_LENGTH).map(|x| x + 1).map(BlockId::Number) {
 		assert_eq!(
-			net.peer(0).light_chain().get_header(id),
+			net.peer(0).light_chain().block_header(id).unwrap(),
-			net.peer(2).chain().block_header(id).map(|h| h.into_inner())
+			net.peer(2).chain().block_header(id).unwrap()
 		);
 	}
 }

util/network/src/host.rs

@@ -983,14 +983,14 @@ impl Host {
 		self.nodes.write().update(node_changes, &*self.reserved_nodes.read());
 	}
 
-	pub fn with_context<F>(&self, protocol: ProtocolId, io: &IoContext<NetworkIoMessage>, action: F) where F: Fn(&NetworkContext) {
+	pub fn with_context<F>(&self, protocol: ProtocolId, io: &IoContext<NetworkIoMessage>, action: F) where F: FnOnce(&NetworkContext) {
 		let reserved = { self.reserved_nodes.read() };
 
 		let context = NetworkContext::new(io, protocol, None, self.sessions.clone(), &reserved);
 		action(&context);
 	}
 
-	pub fn with_context_eval<F, T>(&self, protocol: ProtocolId, io: &IoContext<NetworkIoMessage>, action: F) -> T where F: Fn(&NetworkContext) -> T {
+	pub fn with_context_eval<F, T>(&self, protocol: ProtocolId, io: &IoContext<NetworkIoMessage>, action: F) -> T where F: FnOnce(&NetworkContext) -> T {
 		let reserved = { self.reserved_nodes.read() };
 
 		let context = NetworkContext::new(io, protocol, None, self.sessions.clone(), &reserved);

util/network/src/service.rs

@@ -177,7 +177,7 @@ impl NetworkService {
 	}
 
 	/// Executes action in the network context
-	pub fn with_context<F>(&self, protocol: ProtocolId, action: F) where F: Fn(&NetworkContext) {
+	pub fn with_context<F>(&self, protocol: ProtocolId, action: F) where F: FnOnce(&NetworkContext) {
 		let io = IoContext::new(self.io_service.channel(), 0);
 		let host = self.host.read();
 		if let Some(ref host) = host.as_ref() {
@@ -186,7 +186,7 @@ impl NetworkService {
 	}
 
 	/// Evaluates function in the network context
-	pub fn with_context_eval<F, T>(&self, protocol: ProtocolId, action: F) -> Option<T> where F: Fn(&NetworkContext) -> T {
+	pub fn with_context_eval<F, T>(&self, protocol: ProtocolId, action: F) -> Option<T> where F: FnOnce(&NetworkContext) -> T {
 		let io = IoContext::new(self.io_service.channel(), 0);
 		let host = self.host.read();
 		host.as_ref().map(|ref host| host.with_context_eval(protocol, &io, action))