Extrinsic pool (#182)

* Use latest version of txpool.

* Initial version of the pool.

* Fix abstraction.

* Implement watchers and notifications.

* Return hash from RPC.

* Remove commented code.

* Remove client dep.

* Fix tests.

substrate/substrate/client/src/client.rs

@@ -231,7 +231,7 @@ impl<B, E> Client<B, E> where
 	/// No changes are made.
 	pub fn execution_proof(&self, id: &BlockId, method: &str, call_data: &[u8]) -> error::Result<(Vec<u8>, Vec<Vec<u8>>)> {
 		use call_executor::state_to_execution_proof;
-		
+
 		let result = self.executor.call(id, method, call_data);
 		let result = result?.return_data;
 		let proof = self.backend.state_at(*id).map(|state| state_to_execution_proof(&state))?;
@@ -344,7 +344,8 @@ impl<B, E> Client<B, E> where
 				header: header,
 				is_new_best: is_new_best,
 			};
-			self.import_notification_sinks.lock().retain(|sink| !sink.unbounded_send(notification.clone()).is_err());
+			self.import_notification_sinks.lock()
+				.retain(|sink| sink.unbounded_send(notification.clone()).is_ok());
 		}
 		Ok(ImportResult::Queued)
 	}

substrate/substrate/extrinsic-pool/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "substrate-extrinsic-pool"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+
+[dependencies]
+error-chain = "0.11"
+futures = "0.1"
+log = "0.3"
+parking_lot = "0.4"
+substrate-primitives = { path = "../primitives" }
+transaction-pool = "1.12"

substrate/substrate/extrinsic-pool/src/api.rs

@@ -0,0 +1,64 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot 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.
+
+// Polkadot 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 Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! External API for extrinsic pool.
+
+use std::ops::Deref;
+use txpool::{self, VerifiedTransaction};
+use primitives::{
+	Hash,
+	block::{Extrinsic, ExtrinsicHash},
+};
+
+/// Extrinsic pool error.
+pub trait Error: ::std::error::Error + Send + Sized {
+	/// Try to extract original `txpool::Error`
+	///
+	/// This implementation is optional and used only to
+	/// provide more descriptive error messages for end users
+	/// of RPC API.
+	fn into_pool_error(self) -> Result<txpool::Error, Self> { Err(self) }
+}
+
+impl Error for txpool::Error {
+	fn into_pool_error(self) -> Result<txpool::Error, Self> { Ok(self) }
+}
+
+/// Extrinsic pool.
+pub trait ExtrinsicPool: Send + Sync + 'static {
+	/// Error type
+	type Error: Error;
+
+	/// Submit a collection of extrinsics to the pool.
+	fn submit(&self, xt: Vec<Extrinsic>) -> Result<Vec<ExtrinsicHash>, Self::Error>;
+}
+
+// Blanket implementation for anything that `Derefs` to the pool.
+impl<V, S, E, T> ExtrinsicPool for T where
+	T: Deref<Target=super::Pool<V, S, E>> + Send + Sync + 'static,
+	V: txpool::Verifier<Extrinsic>,
+	S: txpool::Scoring<V::VerifiedTransaction>,
+	V::VerifiedTransaction: txpool::VerifiedTransaction<Hash=Hash>,
+	E: From<V::Error>,
+	E: From<txpool::Error>,
+	E: Error,
+{
+	type Error = E;
+
+	fn submit(&self, xt: Vec<Extrinsic>) -> Result<Vec<ExtrinsicHash>, Self::Error> {
+		self.deref().submit(xt).map(|result| result.into_iter().map(|xt| *xt.hash()).collect())
+	}
+}

substrate/substrate/extrinsic-pool/src/lib.rs

@@ -0,0 +1,37 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot 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.
+
+// Polkadot 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 Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+#![warn(missing_docs)]
+
+//! Generic extrinsic pool.
+
+extern crate futures;
+extern crate parking_lot;
+extern crate substrate_primitives as primitives;
+
+#[macro_use]
+extern crate log;
+
+pub extern crate transaction_pool as txpool;
+
+pub mod api;
+
+mod listener;
+mod pool;
+mod watcher;
+
+pub use self::pool::Pool;
+pub use self::watcher::Watcher;

substrate/substrate/extrinsic-pool/src/listener.rs

@@ -0,0 +1,89 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot 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.
+
+// Polkadot 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 Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::{
+	sync::Arc,
+	collections::HashMap,
+};
+use primitives::Hash;
+use txpool;
+
+use watcher;
+
+#[derive(Default)]
+pub struct Listener {
+	watchers: HashMap<Hash, watcher::Sender>
+}
+
+impl Listener {
+	pub fn create_watcher<T: txpool::VerifiedTransaction<Hash=Hash>>(&mut self, xt: Arc<T>) -> watcher::Watcher {
+		let sender = self.watchers.entry(*xt.hash()).or_insert_with(watcher::Sender::default);
+		sender.new_watcher()
+	}
+
+	pub fn broadcasted(&mut self, hash: &Hash, peers: Vec<String>) {
+		self.fire(hash, |watcher| watcher.broadcast(peers));
+	}
+
+	fn fire<F: FnOnce(&mut watcher::Sender)>(&mut self, hash: &Hash, fun: F) {
+		let clean = if let Some(h) = self.watchers.get_mut(hash) {
+			fun(h);
+			h.is_done()
+		} else {
+			false
+		};
+
+		if clean {
+			self.watchers.remove(hash);
+		}
+	}
+}
+
+impl<T: txpool::VerifiedTransaction<Hash=Hash>> txpool::Listener<T> for Listener {
+	fn added(&mut self, tx: &Arc<T>, old: Option<&Arc<T>>) {
+		if let Some(old) = old {
+			let hash = tx.hash();
+			self.fire(old.hash(), |watcher| watcher.usurped(*hash));
+		}
+	}
+
+	fn dropped(&mut self, tx: &Arc<T>, by: Option<&T>) {
+		self.fire(tx.hash(), |watcher| match by {
+			Some(t) => watcher.usurped(*t.hash()),
+			None => watcher.dropped(),
+		})
+	}
+
+	fn rejected(&mut self, tx: &Arc<T>, reason: &txpool::ErrorKind) {
+		warn!("Extrinsic rejected ({}): {:?}", reason, tx);
+	}
+
+	fn invalid(&mut self, tx: &Arc<T>) {
+		warn!("Extrinsic invalid: {:?}", tx);
+	}
+
+	fn canceled(&mut self, tx: &Arc<T>) {
+		warn!("Extrinsic canceled: {:?}", tx);
+	}
+
+	fn mined(&mut self, tx: &Arc<T>) {
+		// TODO [ToDr] latest block number?
+		let header_hash = 1.into();
+		self.fire(tx.hash(), |watcher| watcher.finalised(header_hash))
+	}
+}
+
+

substrate/substrate/extrinsic-pool/src/pool.rs

@@ -0,0 +1,141 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot 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.
+
+// Polkadot 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 Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::{
+	collections::HashMap,
+	marker::PhantomData,
+	sync::{Arc, Weak},
+};
+
+use futures::sync::mpsc;
+use parking_lot::{RwLock, Mutex};
+use txpool;
+use primitives::{Hash, block::Extrinsic};
+
+use listener::Listener;
+use watcher::Watcher;
+
+/// Extrinsics pool.
+pub struct Pool<V, S, E> where
+	V: txpool::Verifier<Extrinsic>,
+	S: txpool::Scoring<V::VerifiedTransaction>,
+{
+	_error: Mutex<PhantomData<E>>,
+	pool: RwLock<txpool::Pool<
+		V::VerifiedTransaction,
+		S,
+		Listener,
+	>>,
+	verifier: V,
+	import_notification_sinks: Mutex<Vec<mpsc::UnboundedSender<Weak<V::VerifiedTransaction>>>>,
+}
+
+impl<V, S, E> Pool<V, S, E> where
+	V: txpool::Verifier<Extrinsic>,
+	S: txpool::Scoring<V::VerifiedTransaction>,
+	V::VerifiedTransaction: txpool::VerifiedTransaction<Hash=Hash>,
+	E: From<V::Error>,
+	E: From<txpool::Error>,
+{
+	/// Create a new transaction pool.
+	pub fn new(options: txpool::Options, verifier: V, scoring: S) -> Self {
+		Pool {
+			_error: Default::default(),
+			pool: RwLock::new(txpool::Pool::new(Listener::default(), scoring, options)),
+			verifier,
+			import_notification_sinks: Default::default(),
+		}
+	}
+
+	/// Imports a pre-verified extrinsic to the pool.
+	pub fn import(&self, xt: V::VerifiedTransaction) -> Result<Arc<V::VerifiedTransaction>, E> {
+		let result = self.pool.write().import(xt)?;
+
+		let weak = Arc::downgrade(&result);
+		self.import_notification_sinks.lock()
+			.retain(|sink| sink.unbounded_send(weak.clone()).is_ok());
+
+		Ok(result)
+	}
+
+	/// Return an event stream of transactions imported to the pool.
+	pub fn import_notification_stream(&self) -> mpsc::UnboundedReceiver<Weak<V::VerifiedTransaction>> {
+		let (sink, stream) = mpsc::unbounded();
+		self.import_notification_sinks.lock().push(sink);
+		stream
+	}
+
+	/// Invoked when extrinsics are broadcasted.
+	pub fn on_broadcasted(&self, propagated: HashMap<Hash, Vec<String>>) {
+		for (hash, peers) in propagated.into_iter() {
+			self.pool.write().listener_mut().broadcasted(&hash, peers);
+		}
+	}
+
+	/// Imports a bunch of extrinsics to the pool
+	pub fn submit(&self, xts: Vec<Extrinsic>) -> Result<Vec<Arc<V::VerifiedTransaction>>, E> {
+		xts
+			.into_iter()
+			.map(|xt| self.verifier.verify_transaction(xt))
+			.map(|xt| {
+				Ok(self.pool.write().import(xt?)?)
+			})
+			.collect()
+	}
+
+	/// Import a single extrinsic and starts to watch their progress in the pool.
+	pub fn submit_and_watch(&self, xt: Extrinsic) -> Result<Watcher, E> {
+		let xt = self.submit(vec![xt])?.pop().expect("One extrinsic passed; one result returned; qed");
+		Ok(self.pool.write().listener_mut().create_watcher(xt))
+	}
+
+	/// Remove from the pool.
+	pub fn remove(&self, hashes: &[Hash], is_valid: bool) -> Vec<Option<Arc<V::VerifiedTransaction>>> {
+		let mut pool = self.pool.write();
+		let mut results = Vec::with_capacity(hashes.len());
+		for hash in hashes {
+			results.push(pool.remove(hash, is_valid));
+		}
+		results
+	}
+
+	/// Cull transactions from the queue.
+	pub fn cull<R>(&self, senders: Option<&[<V::VerifiedTransaction as txpool::VerifiedTransaction>::Sender]>, ready: R) -> usize where
+		R: txpool::Ready<V::VerifiedTransaction>,
+	{
+		self.pool.write().cull(senders, ready)
+	}
+
+	/// Cull transactions from the queue and then compute the pending set.
+	pub fn cull_and_get_pending<R, F, T>(&self, ready: R, f: F) -> T where
+		R: txpool::Ready<V::VerifiedTransaction> + Clone,
+		F: FnOnce(txpool::PendingIterator<V::VerifiedTransaction, R, S, Listener>) -> T,
+	{
+		let mut pool = self.pool.write();
+		pool.cull(None, ready.clone());
+		f(pool.pending(ready))
+	}
+
+	/// Get the full status of the queue (including readiness)
+	pub fn status<R: txpool::Ready<V::VerifiedTransaction>>(&self, ready: R) -> txpool::Status {
+		self.pool.read().status(ready)
+	}
+
+	/// Returns light status of the pool.
+	pub fn light_status(&self) -> txpool::LightStatus {
+		self.pool.read().light_status()
+	}
+}

substrate/substrate/extrinsic-pool/src/watcher.rs

@@ -0,0 +1,88 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot 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.
+
+// Polkadot 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 Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+use futures::sync::mpsc;
+use primitives::{
+	block::{HeaderHash, ExtrinsicHash}
+};
+
+/// Possible extrinsic status events
+#[derive(Debug, Clone)]
+pub enum Status {
+	/// Extrinsic has been finalised in block with given hash.
+	Finalised(HeaderHash),
+	/// Some state change (perhaps another extrinsic was included) rendered this extrinsic invalid.
+	Usurped(ExtrinsicHash),
+	/// The extrinsic has been broadcast to the given peers.
+	Broadcast(Vec<String>),
+	/// Extrinsic has been dropped from the pool because of the limit.
+	Dropped,
+}
+
+/// Extrinsic watcher.
+///
+/// Represents a stream of status updates for particular extrinsic.
+#[derive(Debug)]
+pub struct Watcher {
+	receiver: mpsc::UnboundedReceiver<Status>,
+}
+
+#[derive(Debug, Default)]
+pub(crate) struct Sender {
+	receivers: Vec<mpsc::UnboundedSender<Status>>,
+	finalised: bool,
+}
+
+impl Sender {
+	/// Add a new watcher to this sender object.
+	pub fn new_watcher(&mut self) -> Watcher {
+		let (tx, receiver) = mpsc::unbounded();
+		self.receivers.push(tx);
+		Watcher {
+			receiver,
+		}
+	}
+
+	/// Some state change (perhaps another extrinsic was included) rendered this extrinsic invalid.
+	pub fn usurped(&mut self, hash: ExtrinsicHash) {
+		self.send(Status::Usurped(hash))
+	}
+
+	/// Extrinsic has been finalised in block with given hash.
+	pub fn finalised(&mut self, hash: HeaderHash) {
+		self.send(Status::Finalised(hash));
+		self.finalised = true;
+	}
+
+	/// Transaction has been dropped from the pool because of the limit.
+	pub fn dropped(&mut self) {
+		self.send(Status::Dropped);
+	}
+
+	/// The extrinsic has been broadcast to the given peers.
+	pub fn broadcast(&mut self, peers: Vec<String>) {
+		self.send(Status::Broadcast(peers))
+	}
+
+	/// Returns true if the are no more listeners for this extrinsic or it was finalised.
+	pub fn is_done(&self) -> bool {
+		self.finalised || self.receivers.is_empty()
+	}
+
+	fn send(&mut self, status: Status) {
+		self.receivers.retain(|sender| sender.unbounded_send(status.clone()).is_ok())
+	}
+}

substrate/substrate/network/src/protocol.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.?
 
-use std::collections::{HashMap, HashSet, BTreeMap};
+use std::collections::{HashMap, HashSet};
 use std::{mem, cmp};
 use std::sync::Arc;
 use std::time;
@@ -24,7 +24,7 @@ use serde_json;
 use primitives::block::{HeaderHash, ExtrinsicHash, Number as BlockNumber, Header, Id as BlockId};
 use primitives::{Hash, blake2_256};
 use runtime_support::Hashable;
-use network::{PeerId, NodeId};
+use network::PeerId;
 
 use message::{self, Message};
 use sync::{ChainSync, Status as SyncStatus, SyncState};
@@ -103,15 +103,6 @@ pub struct PeerInfo {
 	pub best_number: BlockNumber,
 }
 
-/// Transaction stats
-#[derive(Debug)]
-pub struct TransactionStats {
-	/// Block number where this TX was first seen.
-	pub first_seen: u64,
-	/// Peers it was propagated to.
-	pub propagated_to: BTreeMap<NodeId, usize>,
-}
-
 impl Protocol {
 	/// Create a new instance.
 	pub fn new(config: ProtocolConfig, chain: Arc<Client>, on_demand: Option<Arc<OnDemandService>>, transaction_pool: Arc<TransactionPool>) -> error::Result<Protocol>  {
@@ -463,15 +454,31 @@ impl Protocol {
 
 		let transactions = self.transaction_pool.transactions();
 
+		let mut propagated_to = HashMap::new();
 		let mut peers = self.peers.write();
 		for (peer_id, ref mut peer) in peers.iter_mut() {
-			let to_send: Vec<_> = transactions.iter().filter_map(|&(hash, ref t)|
-				if peer.known_transactions.insert(hash.clone()) { Some(t.clone()) } else { None }).collect();
+			let (hashes, to_send): (Vec<_>, Vec<_>) = transactions
+				.iter()
+				.cloned()
+				.filter(|&(hash, _)| peer.known_transactions.insert(hash))
+				.unzip();
+
 			if !to_send.is_empty() {
+				let node_id = io.peer_session_info(*peer_id).map(|info| match info.id {
+					Some(id) => format!("{}@{:x}", info.remote_address, id),
+					None => info.remote_address.clone(),
+				});
+
+				if let Some(id) = node_id {
+					for hash in hashes {
+						propagated_to.entry(hash).or_insert_with(Vec::new).push(id.clone());
+					}
+				}
 				trace!(target: "sync", "Sending {} transactions to {}", to_send.len(), peer_id);
 				self.send_message(io, *peer_id, Message::Transactions(to_send));
 			}
 		}
+		self.transaction_pool.on_broadcasted(propagated_to);
 	}
 
 	/// Send Status message
@@ -551,10 +558,6 @@ impl Protocol {
 		self.on_demand.as_ref().map(|s| s.on_remote_response(io, peer_id, response));
 	}
 
-	pub fn transactions_stats(&self) -> BTreeMap<ExtrinsicHash, TransactionStats> {
-		BTreeMap::new()
-	}
-
 	pub fn chain(&self) -> &Client {
 		&*self.chain
 	}

substrate/substrate/network/src/service.rs

@@ -14,8 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.?
 
+use std::collections::HashMap;
 use std::sync::Arc;
-use std::collections::{BTreeMap};
 use std::io;
 use std::time::Duration;
 use futures::sync::{oneshot, mpsc};
@@ -26,7 +26,7 @@ use primitives::block::{ExtrinsicHash, Header, HeaderHash};
 use primitives::Hash;
 use core_io::{TimerToken};
 use io::NetSyncIo;
-use protocol::{Protocol, ProtocolStatus, PeerInfo as ProtocolPeerInfo, TransactionStats};
+use protocol::{Protocol, ProtocolStatus, PeerInfo as ProtocolPeerInfo};
 use config::{ProtocolConfig};
 use error::Error;
 use chain::Client;
@@ -75,8 +75,6 @@ pub trait SyncProvider: Send + Sync {
 	fn peers(&self) -> Vec<PeerInfo>;
 	/// Get this node id if available.
 	fn node_id(&self) -> Option<String>;
-	/// Returns propagation count for pending transactions.
-	fn transactions_stats(&self) -> BTreeMap<ExtrinsicHash, TransactionStats>;
 }
 
 /// Transaction pool interface
@@ -85,6 +83,8 @@ pub trait TransactionPool: Send + Sync {
 	fn transactions(&self) -> Vec<(ExtrinsicHash, Vec<u8>)>;
 	/// Import a transction into the pool.
 	fn import(&self, transaction: &[u8]) -> Option<ExtrinsicHash>;
+	/// Notify the pool about transactions broadcast.
+	fn on_broadcasted(&self, propagations: HashMap<ExtrinsicHash, Vec<String>>);
 }
 
 /// ConsensusService
@@ -249,10 +249,6 @@ impl SyncProvider for Service {
 	fn node_id(&self) -> Option<String> {
 		self.network.external_url()
 	}
-
-	fn transactions_stats(&self) -> BTreeMap<ExtrinsicHash, TransactionStats> {
-		self.handler.protocol.transactions_stats()
-	}
 }
 
 /// ConsensusService

substrate/substrate/network/src/test/mod.rs

@@ -204,6 +204,8 @@ impl TransactionPool for EmptyTransactionPool {
 	fn import(&self, _transaction: &[u8]) -> Option<ExtrinsicHash> {
 		None
 	}
+
+	fn on_broadcasted(&self, _: HashMap<ExtrinsicHash, Vec<String>>) {}
 }
 
 pub struct TestNet {

substrate/substrate/rpc/Cargo.toml

@@ -12,6 +12,7 @@ log = "0.3"
 parking_lot = "0.4"
 substrate-client = { path = "../client" }
 substrate-executor = { path = "../executor" }
+substrate-extrinsic-pool = { path = "../extrinsic-pool" }
 substrate-primitives = { path = "../primitives" }
 substrate-state-machine = { path = "../state-machine" }
 tokio-core = "0.1.12"

substrate/substrate/rpc/src/author/error.rs

@@ -16,12 +16,12 @@
 
 //! Authoring RPC module errors.
 
-use client;
+use extrinsic_pool::txpool;
 use rpc;
 
 error_chain! {
 	links {
-		Client(client::error::Error, client::error::ErrorKind) #[doc = "Client error"];
+		Pool(txpool::Error, txpool::ErrorKind) #[doc = "Pool error"];
 	}
 	errors {
 		/// Not implemented yet
@@ -29,15 +29,10 @@ error_chain! {
 			description("not yet implemented"),
 			display("Method Not Implemented"),
 		}
-		/// Invalid format
-		InvalidFormat {
-			description("invalid format"),
-			display("Invalid format for the extrinsic data"),
-		}
-		/// Some error with the pool since the import failed.
-		PoolError {
-			description("pool import failed"),
-			display("Pool import failed"),
+		/// Verification error
+		Verification(e: Box<::std::error::Error + Send>) {
+			description("extrinsic verification error"),
+			display("Extrinsic verification error: {}", e.description()),
 		}
 	}
 }
@@ -50,6 +45,7 @@ impl From<Error> for rpc::Error {
 				message: "Not implemented yet".into(),
 				data: None,
 			},
+			// TODO [ToDr] Unwrap Pool errors.
 			_ => rpc::Error::internal_error(),
 		}
 	}

substrate/substrate/rpc/src/author/mod.rs

@@ -16,7 +16,9 @@
 
 //! Substrate block-author/full-node API.
 
-use primitives::block::Extrinsic;
+use std::sync::Arc;
+use primitives::block::{Extrinsic, ExtrinsicHash};
+use extrinsic_pool::api::{Error, ExtrinsicPool};
 
 pub mod error;
 
@@ -30,6 +32,20 @@ build_rpc_trait! {
 	pub trait AuthorApi {
 		/// Submit extrinsic for inclusion in block.
 		#[rpc(name = "author_submitExtrinsic")]
-		fn submit_extrinsic(&self, Extrinsic) -> Result<()>;
+		fn submit_extrinsic(&self, Extrinsic) -> Result<ExtrinsicHash>;
+	}
+}
+
+impl<T> AuthorApi for Arc<T> where
+	T: ExtrinsicPool,
+{
+	fn submit_extrinsic(&self, xt: Extrinsic) -> Result<ExtrinsicHash> {
+		self
+			.submit(vec![xt])
+			.map(|mut res| res.pop().expect("One extrinsic passed; one result back; qed"))
+			.map_err(|e| e.into_pool_error()
+				.map(Into::into)
+				.unwrap_or_else(|e| error::ErrorKind::Verification(Box::new(e)).into())
+			)
 	}
 }

substrate/substrate/rpc/src/author/tests.rs

@@ -15,37 +15,53 @@
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
 use super::*;
-use super::error::*;
 
-use std::sync::Arc;
+use std::{fmt, sync::Arc};
+use extrinsic_pool::api;
 use parking_lot::Mutex;
 use primitives::block;
 
 #[derive(Default)]
 struct DummyTxPool {
-	submitted: Vec<block::Extrinsic>,
+	submitted: Mutex<Vec<block::Extrinsic>>,
 }
 
-impl AuthorApi for Arc<Mutex<DummyTxPool>> {
+#[derive(Debug)]
+struct Error;
+impl api::Error for Error {}
+impl ::std::error::Error for Error {
+	fn description(&self) -> &str { "Error" }
+}
+impl fmt::Display for Error {
+	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+		fmt::Debug::fmt(self, fmt)
+	}
+}
+
+impl api::ExtrinsicPool for DummyTxPool {
+	type Error = Error;
+
 	/// Submit extrinsic for inclusion in block.
-	fn submit_extrinsic(&self, xt: Extrinsic) -> Result<()> {
-		let mut s = self.lock();
-		if s.submitted.len() < 1 {
-			s.submitted.push(xt);
-			Ok(())
+	fn submit(&self, xt: Vec<Extrinsic>) -> ::std::result::Result<Vec<ExtrinsicHash>, Self::Error> {
+		let mut submitted = self.submitted.lock();
+		if submitted.len() < 1 {
+			let hashes = xt.iter().map(|_xt| 1.into()).collect();
+			submitted.extend(xt);
+			Ok(hashes)
 		} else {
-			Err(ErrorKind::PoolError.into())
+			Err(Error)
 		}
 	}
 }
 
 #[test]
 fn submit_transaction_should_not_cause_error() {
-	let p = Arc::new(Mutex::new(DummyTxPool::default()));
+	let p = Arc::new(DummyTxPool::default());
+	let hash: ExtrinsicHash = 1.into();
 
 	assert_matches!(
 		AuthorApi::submit_extrinsic(&p, block::Extrinsic(vec![])),
-		Ok(())
+		Ok(hash)
 	);
 	assert!(
 		AuthorApi::submit_extrinsic(&p, block::Extrinsic(vec![])).is_err()

substrate/substrate/rpc/src/lib.rs

@@ -22,6 +22,7 @@ extern crate jsonrpc_core as rpc;
 extern crate jsonrpc_pubsub;
 extern crate parking_lot;
 extern crate substrate_client as client;
+extern crate substrate_extrinsic_pool as extrinsic_pool;
 extern crate substrate_primitives as primitives;
 extern crate substrate_state_machine as state_machine;
 extern crate tokio_core;