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.

polkadot/cli/src/lib.rs

@@ -61,39 +61,11 @@ mod informant;
 use std::io;
 use std::net::SocketAddr;
 use std::path::{Path, PathBuf};
-use std::sync::Arc;
 
 use futures::sync::mpsc;
 use futures::{Sink, Future, Stream};
 use tokio_core::reactor;
-use parking_lot::Mutex;
 use service::ChainSpec;
-use primitives::block::Extrinsic;
-
-struct RpcTransactionPool {
-	inner: Arc<Mutex<txpool::TransactionPool>>,
-	network: Arc<network::Service>,
-}
-
-impl substrate_rpc::author::AuthorApi for RpcTransactionPool {
-	fn submit_extrinsic(&self, xt: Extrinsic) -> substrate_rpc::author::error::Result<()> {
-		use primitives::hexdisplay::HexDisplay;
-		use polkadot_runtime::UncheckedExtrinsic;
-		use codec::Slicable;
-
-		info!("Extrinsic submitted: {}", HexDisplay::from(&xt.0));
-		let decoded = xt.using_encoded(|ref mut s| UncheckedExtrinsic::decode(s))
-			.ok_or(substrate_rpc::author::error::ErrorKind::InvalidFormat)?;
-
-		info!("Correctly formatted: {:?}", decoded);
-
-		self.inner.lock().import(decoded)
-			.map_err(|_| substrate_rpc::author::error::ErrorKind::PoolError)?;
-
-		self.network.trigger_repropagate();
-		Ok(())
-	}
-}
 
 struct Configuration(service::Configuration);
 
@@ -238,11 +210,12 @@ fn run_until_exit<B, E>(mut core: reactor::Core, service: service::Service<B, E>
 
 		let handler = || {
 			let chain = rpc::apis::chain::Chain::new(service.client(), core.remote());
-			let pool = RpcTransactionPool {
+			rpc::rpc_handler(
-				inner: service.transaction_pool(),
+				service.client(),
-				network: service.network(),
+				chain,
-			};
+				service.transaction_pool(),
-			rpc::rpc_handler(service.client(), chain, pool, Configuration(config.clone()))
+				Configuration(config.clone()),
+			)
 		};
 		(
 			start_server(http_address, |address| rpc::start_http(address, handler())),

polkadot/consensus/src/lib.rs

@@ -78,7 +78,6 @@ use tokio_core::reactor::{Handle, Timeout, Interval};
 
 use futures::prelude::*;
 use futures::future::{self, Shared};
-use parking_lot::Mutex;
 use collation::CollationFetch;
 use dynamic_inclusion::DynamicInclusion;
 
@@ -226,7 +225,7 @@ pub struct ProposerFactory<C, N, P> {
 	/// The client instance.
 	pub client: Arc<C>,
 	/// The transaction pool.
-	pub transaction_pool: Arc<Mutex<TransactionPool>>,
+	pub transaction_pool: Arc<TransactionPool>,
 	/// The backing network handle.
 	pub network: N,
 	/// Parachain collators.
@@ -319,7 +318,7 @@ pub struct Proposer<C: PolkadotApi, R, P> {
 	random_seed: Hash,
 	router: R,
 	table: Arc<SharedTable>,
-	transaction_pool: Arc<Mutex<TransactionPool>>,
+	transaction_pool: Arc<TransactionPool>,
 }
 
 impl<C, R, P> bft::Proposer for Proposer<C, R, P>
@@ -495,17 +494,16 @@ impl<C, R, P> bft::Proposer for Proposer<C, R, P>
 		use primitives::bft::{MisbehaviorKind, MisbehaviorReport};
 		use polkadot_runtime::{Call, Extrinsic, UncheckedExtrinsic, ConsensusCall};
 
+
 		let local_id = self.local_key.public().0;
-		let mut pool = self.transaction_pool.lock();
 		let mut next_index = {
 			let readiness_evaluator = Ready::create(self.parent_id.clone(), &*self.client);
-
+			let cur_index = self.transaction_pool.cull_and_get_pending(readiness_evaluator, |pending| pending
-			pool.cull(None, readiness_evaluator.clone());
-			let cur_index = pool.pending(readiness_evaluator)
 				.filter(|tx| tx.as_ref().as_ref().signed == local_id)
 				.last()
 				.map(|tx| Ok(tx.as_ref().as_ref().index))
-				.unwrap_or_else(|| self.client.index(&self.parent_id, local_id));
+				.unwrap_or_else(|| self.client.index(&self.parent_id, local_id))
+			);
 
 			match cur_index {
 				Ok(cur_index) => cur_index + 1,
@@ -541,7 +539,7 @@ impl<C, R, P> bft::Proposer for Proposer<C, R, P>
 			let signature = self.local_key.sign(&extrinsic.encode()).into();
 			let uxt = UncheckedExtrinsic { extrinsic, signature };
 
-			pool.import(uxt).expect("locally signed extrinsic is valid; qed");
+			self.transaction_pool.import_unchecked_extrinsic(uxt).expect("locally signed extrinsic is valid; qed");
 		}
 	}
 }
@@ -609,7 +607,7 @@ pub struct CreateProposal<C: PolkadotApi, R, P: Collators>  {
 	parent_number: BlockNumber,
 	parent_id: C::CheckedBlockId,
 	client: Arc<C>,
-	transaction_pool: Arc<Mutex<TransactionPool>>,
+	transaction_pool: Arc<TransactionPool>,
 	collation: CollationFetch<P, C>,
 	router: R,
 	table: Arc<SharedTable>,
@@ -631,37 +629,33 @@ impl<C, R, P> CreateProposal<C, R, P>
 			candidates,
 		)?;
 
-		let readiness_evaluator = Ready::create(self.parent_id.clone(), &*self.client);
-
 		{
-			let mut pool = self.transaction_pool.lock();
+			let readiness_evaluator = Ready::create(self.parent_id.clone(), &*self.client);
 			let mut unqueue_invalid = Vec::new();
-			let mut pending_size = 0;
+			self.transaction_pool.cull_and_get_pending(readiness_evaluator, |pending_iterator| {
-
+				let mut pending_size = 0;
-			pool.cull(None, readiness_evaluator.clone());
+				for pending in pending_iterator {
-			for pending in pool.pending(readiness_evaluator.clone()) {
+					// skip and cull transactions which are too large.
-				// skip and cull transactions which are too large.
+					if pending.encoded_size() > MAX_TRANSACTIONS_SIZE {
-				if pending.encoded_size() > MAX_TRANSACTIONS_SIZE {
-					unqueue_invalid.push(pending.hash().clone());
-					continue
-				}
-
-				if pending_size + pending.encoded_size() >= MAX_TRANSACTIONS_SIZE { break }
-
-				match block_builder.push_extrinsic(pending.as_transaction().clone()) {
-					Ok(()) => {
-						pending_size += pending.encoded_size();
-					}
-					Err(e) => {
-						trace!(target: "transaction-pool", "Invalid transaction: {}", e);
 						unqueue_invalid.push(pending.hash().clone());
+						continue
+					}
+
+					if pending_size + pending.encoded_size() >= MAX_TRANSACTIONS_SIZE { break }
+
+					match block_builder.push_extrinsic(pending.as_transaction().clone()) {
+						Ok(()) => {
+							pending_size += pending.encoded_size();
+						}
+						Err(e) => {
+							trace!(target: "transaction-pool", "Invalid transaction: {}", e);
+							unqueue_invalid.push(pending.hash().clone());
+						}
 					}
 				}
-			}
+			});
 
-			for tx_hash in unqueue_invalid {
+			self.transaction_pool.remove(&unqueue_invalid, false);
-				pool.remove(&tx_hash, false);
-			}
 		}
 
 		let polkadot_block = block_builder.bake();

polkadot/consensus/src/service.rs

@@ -28,7 +28,6 @@ use client::{BlockchainEvents, ChainHead};
 use ed25519;
 use futures::prelude::*;
 use futures::{future, Canceled};
-use parking_lot::Mutex;
 use polkadot_api::LocalPolkadotApi;
 use polkadot_primitives::AccountId;
 use polkadot_primitives::parachain::{Id as ParaId, BlockData, Extrinsic, CandidateReceipt};
@@ -237,7 +236,7 @@ impl Service {
 		client: Arc<C>,
 		api: Arc<A>,
 		network: Arc<net::ConsensusService>,
-		transaction_pool: Arc<Mutex<TransactionPool>>,
+		transaction_pool: Arc<TransactionPool>,
 		parachain_empty_duration: Duration,
 		key: ed25519::Pair,
 	) -> Service

polkadot/service/src/config.rs

@@ -22,7 +22,7 @@ pub use network::NetworkConfiguration;
 
 /// The chain specification (this should eventually be replaced by a more general JSON-based chain
 /// specification).
-#[derive(Clone)]
+#[derive(Clone, Copy)]
 pub enum ChainSpec {
 	/// Whatever the current runtime is, with just Alice as an auth.
 	Development,
@@ -33,6 +33,7 @@ pub enum ChainSpec {
 }
 
 /// Service configuration.
+#[derive(Clone)]
 pub struct Configuration {
 	/// Node roles.
 	pub roles: Role,
@@ -63,21 +64,3 @@ impl Default for Configuration {
 		}
 	}
 }
-
-impl Clone for Configuration {
-	fn clone(&self) -> Configuration {
-		Configuration {
-			roles: self.roles.clone(),
-			transaction_pool: transaction_pool::Options {
-				max_count: self.transaction_pool.max_count.clone(),
-				max_mem_usage: self.transaction_pool.max_mem_usage.clone(),
-				max_per_sender: self.transaction_pool.max_per_sender.clone(),
-			},
-			network: self.network.clone(),
-			keystore_path: self.keystore_path.clone(),
-			database_path: self.database_path.clone(),
-			keys: self.keys.clone(),
-			chain_spec: self.chain_spec.clone(),
-		}
-	}
-}

polkadot/service/src/lib.rs

@@ -50,14 +50,14 @@ extern crate hex_literal;
 mod error;
 mod config;
 
+use std::collections::HashMap;
 use std::sync::Arc;
 use std::thread;
 use futures::prelude::*;
-use parking_lot::Mutex;
 use tokio_core::reactor::Core;
 use codec::Slicable;
-use primitives::block::{Id as BlockId, Extrinsic, ExtrinsicHash, HeaderHash, Header};
+use primitives::block::{Id as BlockId, ExtrinsicHash, HeaderHash, Header};
-use primitives::{AuthorityId, hashing};
+use primitives::{AuthorityId};
 use transaction_pool::TransactionPool;
 use substrate_executor::NativeExecutor;
 use polkadot_executor::Executor as LocalDispatch;
@@ -80,13 +80,13 @@ pub struct Service<B, E> {
 	thread: Option<thread::JoinHandle<()>>,
 	client: Arc<Client<B, E>>,
 	network: Arc<network::Service>,
-	transaction_pool: Arc<Mutex<TransactionPool>>,
+	transaction_pool: Arc<TransactionPool>,
 	signal: Option<Signal>,
 	_consensus: Option<consensus::Service>,
 }
 
 struct TransactionPoolAdapter<B, E, A> where A: Send + Sync, E: Send + Sync {
-	pool: Arc<Mutex<TransactionPool>>,
+	pool: Arc<TransactionPool>,
 	client: Arc<Client<B, E>>,
 	api: Arc<A>,
 }
@@ -108,19 +108,22 @@ impl<B, E, A> network::TransactionPool for TransactionPoolAdapter<B, E, A>
 		};
 
 		let id = self.api.check_id(BlockId::Hash(best_block)).expect("Best block is always valid; qed.");
-		let mut pool = self.pool.lock();
+		let ready = transaction_pool::Ready::create(id, &*self.api);
-		pool.cull(None, transaction_pool::Ready::create(id.clone(), &*self.api));
+
-		pool.pending(transaction_pool::Ready::create(id, &*self.api)).map(|t| {
+		self.pool.cull_and_get_pending(ready, |pending| pending
-			let hash = ::primitives::Hash::from(&t.hash()[..]);
+			.map(|t| {
-			let tx = codec::Slicable::encode(t.as_transaction());
+				let hash = ::primitives::Hash::from(&t.hash()[..]);
-			(hash, tx)
+				let tx = codec::Slicable::encode(t.as_transaction());
-		}).collect()
+				(hash, tx)
+			})
+			.collect()
+		)
 	}
 
 	fn import(&self, transaction: &[u8]) -> Option<ExtrinsicHash> {
-		if let Some(tx) = codec::Slicable::decode(&mut &transaction[..]) {
+		if let Some(uxt) = codec::Slicable::decode(&mut &transaction[..]) {
-			match self.pool.lock().import(tx) {
+			match self.pool.import_unchecked_extrinsic(uxt) {
-				Ok(t) => Some(t.hash()[..].into()),
+				Ok(xt) => Some(*xt.hash()),
 				Err(e) => match *e.kind() {
 					transaction_pool::ErrorKind::AlreadyImported(hash) => Some(hash[..].into()),
 					_ => {
@@ -134,6 +137,10 @@ impl<B, E, A> network::TransactionPool for TransactionPoolAdapter<B, E, A>
 			None
 		}
 	}
+
+	fn on_broadcasted(&self, propagations: HashMap<ExtrinsicHash, Vec<String>>) {
+		self.pool.on_broadcasted(propagations)
+	}
 }
 
 pub struct ChainConfig {
@@ -341,7 +348,7 @@ impl<B, E> Service<B, E>
 			C: Fn(
 					Arc<Client<B, E>>,
 					Arc<network::Service>,
-					Arc<Mutex<TransactionPool>>,
+					Arc<TransactionPool>,
 					&Keystore
 				) -> Result<Option<consensus::Service>, error::Error>,
 			A: PolkadotApi + Send + Sync + 'static,
@@ -383,7 +390,7 @@ impl<B, E> Service<B, E>
 		let api = api_creator(client.clone());
 		let best_header = client.best_block_header()?;
 		info!("Starting Polkadot. Best block is #{}", best_header.number);
-		let transaction_pool = Arc::new(Mutex::new(TransactionPool::new(config.transaction_pool)));
+		let transaction_pool = Arc::new(TransactionPool::new(config.transaction_pool));
 		let transaction_pool_adapter = Arc::new(TransactionPoolAdapter {
 			pool: transaction_pool.clone(),
 			client: client.clone(),
@@ -414,14 +421,28 @@ impl<B, E> Service<B, E>
 
 				thread_barrier.wait();
 				let mut core = Core::new().expect("tokio::Core could not be created");
-				let events = client.import_notification_stream().for_each(move |notification| {
-					network.on_block_imported(notification.hash, &notification.header);
-					prune_imported(&*client, &*txpool, notification.hash);
 
-					Ok(())
+				// block notifications
-				});
+				let network1 = network.clone();
+				let txpool1 = txpool.clone();
+				let events = client.import_notification_stream()
+					.for_each(move |notification| {
+						network1.on_block_imported(notification.hash, &notification.header);
+						prune_imported(&*api, &*txpool1, notification.hash);
 
+						Ok(())
+					});
 				core.handle().spawn(events);
+
+				// transaction notifications
+				let events = txpool.import_notification_stream()
+					// TODO [ToDr] Consider throttling?
+					.for_each(move |_| {
+						network.trigger_repropagate();
+						Ok(())
+					});
+				core.handle().spawn(events);
+
 				if let Err(e) = core.run(exit) {
 					debug!("Polkadot service event loop shutdown with {:?}", e);
 				}
@@ -457,30 +478,22 @@ impl<B, E> Service<B, E>
 	}
 
 	/// Get shared transaction pool instance.
-	pub fn transaction_pool(&self) -> Arc<Mutex<TransactionPool>> {
+	pub fn transaction_pool(&self) -> Arc<TransactionPool> {
 		self.transaction_pool.clone()
 	}
 }
 
-fn prune_transactions(pool: &mut TransactionPool, extrinsics: &[Extrinsic]) {
-	for extrinsic in extrinsics {
-		let hash: _ = hashing::blake2_256(&extrinsic.encode()).into();
-		pool.remove(&hash, true);
-	}
-}
-
 /// Produce a task which prunes any finalized transactions from the pool.
-pub fn prune_imported<B, E>(client: &Client<B, E>, pool: &Mutex<TransactionPool>, hash: HeaderHash)
+pub fn prune_imported<A>(api: &A, pool: &TransactionPool, hash: HeaderHash)
 	where
-		B: Backend + Send + Sync,
+		A: PolkadotApi,
-		E: CallExecutor + Send + Sync,
-		client::error::Error: From<<<B as Backend>::State as state_machine::backend::Backend>::Error>
 {
-	let id = BlockId::Hash(hash);
+	match api.check_id(BlockId::Hash(hash)) {
-	match client.body(&id) {
+		Ok(id) => {
-		Ok(Some(body)) => prune_transactions(&mut *pool.lock(), &body[..]),
+			let ready = transaction_pool::Ready::create(id, api);
-		Ok(None) => warn!("Missing imported block {:?}", hash),
+			pool.cull(None, ready);
-		Err(e) => warn!("Failed to fetch block: {:?}", e),
+		},
+		Err(e) => warn!("Failed to check block id: {:?}", e),
 	}
 }
 

polkadot/transaction-pool/Cargo.toml

@@ -4,15 +4,14 @@ version = "0.1.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 
 [dependencies]
-log = "0.4.0"
+log = "0.3.0"
-transaction-pool = "1.12.0"
 error-chain = "0.11"
 polkadot-api = { path = "../api" }
 polkadot-primitives = { path = "../primitives" }
 polkadot-runtime = { path = "../runtime" }
 substrate-client = { path = "../../substrate/client" }
-substrate-rpc = { path = "../../substrate/rpc" }
+substrate-codec = { path = "../../substrate/codec" }
+substrate-extrinsic-pool = { path = "../../substrate/extrinsic-pool" }
 substrate-primitives = { path = "../../substrate/primitives" }
 substrate-runtime-primitives = { path = "../../substrate/runtime/primitives" }
-substrate-codec = { path = "../../substrate/codec" }
 ed25519 = { path = "../../substrate/ed25519" }

polkadot/transaction-pool/src/error.rs

@@ -0,0 +1,61 @@
+// 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 extrinsic_pool::{self, txpool};
+use primitives::Hash;
+use runtime::UncheckedExtrinsic;
+
+error_chain! {
+	links {
+		Pool(txpool::Error, txpool::ErrorKind);
+	}
+	errors {
+		/// Unexpected extrinsic format submitted
+		InvalidExtrinsicFormat {
+			description("Invalid extrinsic format."),
+			display("Invalid extrinsic format."),
+		}
+		/// Attempted to queue an inherent transaction.
+		IsInherent(xt: UncheckedExtrinsic) {
+			description("Inherent transactions cannot be queued."),
+			display("Inehrent transactions cannot be queued."),
+		}
+		/// Attempted to queue a transaction with bad signature.
+		BadSignature(xt: UncheckedExtrinsic) {
+			description("Transaction had bad signature."),
+			display("Transaction had bad signature."),
+		}
+		/// Attempted to queue a transaction that is already in the pool.
+		AlreadyImported(hash: Hash) {
+			description("Transaction is already in the pool."),
+			display("Transaction {:?} is already in the pool.", hash),
+		}
+		/// Import error.
+		Import(err: Box<::std::error::Error + Send>) {
+			description("Error importing transaction"),
+			display("Error importing transaction: {}", err.description()),
+		}
+	}
+}
+
+impl extrinsic_pool::api::Error for Error {
+	fn into_pool_error(self) -> ::std::result::Result<txpool::Error, Self> {
+		match self {
+			Error(ErrorKind::Pool(e), c) => Ok(txpool::Error(e, c)),
+			e => Err(e),
+		}
+	}
+}

polkadot/transaction-pool/src/lib.rs

@@ -1,4 +1,4 @@
-// Copyright 2017 Parity Technologies (UK) Ltd.
+// Copyright 2018 Parity Technologies (UK) Ltd.
 // This file is part of Polkadot.
 
 // Polkadot is free software: you can redistribute it and/or modify
@@ -16,12 +16,12 @@
 
 extern crate ed25519;
 extern crate substrate_codec as codec;
+extern crate substrate_extrinsic_pool as extrinsic_pool;
 extern crate substrate_primitives as substrate_primitives;
-extern crate substrate_runtime_primitives as substrate_runtime_primitives;
+extern crate substrate_runtime_primitives;
 extern crate polkadot_runtime as runtime;
 extern crate polkadot_primitives as primitives;
 extern crate polkadot_api;
-extern crate transaction_pool;
 
 #[macro_use]
 extern crate error_chain;
@@ -29,19 +29,27 @@ extern crate error_chain;
 #[macro_use]
 extern crate log;
 
-use std::collections::HashMap;
+mod error;
-use std::cmp::Ordering;
-use std::sync::Arc;
 
+use std::{
+	cmp::Ordering,
+	collections::HashMap,
+	ops::Deref,
+	sync::Arc,
+};
+
+use codec::Slicable;
+use extrinsic_pool::{Pool, txpool::{self, Readiness, scoring::{Change, Choice}}};
 use polkadot_api::PolkadotApi;
-use primitives::{AccountId, Timestamp, Hash};
 use primitives::parachain::CandidateReceipt;
+use primitives::{AccountId, Timestamp, Hash};
 use runtime::{Block, UncheckedExtrinsic, TimestampCall, ParachainsCall, Call};
+use substrate_primitives::block::{Extrinsic, ExtrinsicHash};
+use substrate_primitives::hexdisplay::HexDisplay;
 use substrate_runtime_primitives::traits::{Bounded, Checkable};
-use transaction_pool::{Transaction, Pool, Readiness};
-use transaction_pool::scoring::{Change, Choice};
 
-pub use transaction_pool::{Options, Status, LightStatus, NoopListener, VerifiedTransaction as VerifiedTransactionOps};
+pub use extrinsic_pool::txpool::{Options, Status, LightStatus, VerifiedTransaction as VerifiedTransactionOps};
+pub use error::{Error, ErrorKind, Result};
 
 /// Useful functions for working with Polkadot blocks.
 pub struct PolkadotBlock {
@@ -127,48 +135,17 @@ impl From<PolkadotBlock> for Block {
 	}
 }
 
-/// Iterator over pending transactions.
-pub type PendingIterator<'a, C> =
-	transaction_pool::PendingIterator<'a, VerifiedTransaction, Ready<'a, C>, Scoring, NoopListener>;
-
-error_chain! {
-	errors {
-		/// Attempted to queue an inherent transaction.
-		IsInherent(xt: UncheckedExtrinsic) {
-			description("Inherent transactions cannot be queued."),
-			display("Inehrent transactions cannot be queued."),
-		}
-		/// Attempted to queue a transaction with bad signature.
-		BadSignature(xt: UncheckedExtrinsic) {
-			description("Transaction had bad signature."),
-			display("Transaction had bad signature."),
-		}
-		/// Attempted to queue a transaction that is already in the pool.
-		AlreadyImported(hash: Hash) {
-			description("Transaction is already in the pool."),
-			display("Transaction {:?} is already in the pool.", hash),
-		}
-		/// Import error.
-		Import(err: Box<::std::error::Error + Send>) {
-			description("Error importing transaction"),
-			display("Error importing transaction: {}", err.description()),
-		}
-	}
-}
-
 /// A verified transaction which should be includable and non-inherent.
 #[derive(Debug, Clone)]
 pub struct VerifiedTransaction {
 	inner: <UncheckedExtrinsic as Checkable>::Checked,
-	hash: Hash,
+	hash: ExtrinsicHash,
-	address: AccountId,
-	insertion_id: u64,
 	encoded_size: usize,
 }
 
 impl VerifiedTransaction {
 	/// Attempt to verify a transaction.
-	fn create(xt: UncheckedExtrinsic, insertion_id: u64) -> Result<Self> {
+	fn create(xt: UncheckedExtrinsic) -> Result<Self> {
 		if !xt.is_signed() {
 			bail!(ErrorKind::IsInherent(xt))
 		}
@@ -176,15 +153,11 @@ impl VerifiedTransaction {
 		let message = codec::Slicable::encode(&xt);
 		match xt.check() {
 			Ok(xt) => {
-				// TODO: make transaction-pool use generic types.
 				let hash = substrate_primitives::hashing::blake2_256(&message);
-				let address = xt.signed;
 				Ok(VerifiedTransaction {
 					inner: xt,
 					hash: hash.into(),
 					encoded_size: message.len(),
-					address,
-					insertion_id,
 				})
 			}
 			Err(xt) => Err(ErrorKind::BadSignature(xt).into()),
@@ -208,7 +181,7 @@ impl VerifiedTransaction {
 
 	/// Get the account ID of the sender of this transaction.
 	pub fn sender(&self) -> &AccountId {
-		&self.address
+		&self.inner.signed
 	}
 
 	/// Get encoded size of the transaction.
@@ -223,16 +196,16 @@ impl AsRef< <UncheckedExtrinsic as Checkable>::Checked > for VerifiedTransaction
 	}
 }
 
-impl transaction_pool::VerifiedTransaction for VerifiedTransaction {
+impl txpool::VerifiedTransaction for VerifiedTransaction {
 	type Hash = Hash;
 	type Sender = AccountId;
 
-	fn hash(&self) -> &Hash {
+	fn hash(&self) -> &Self::Hash {
 		&self.hash
 	}
 
-	fn sender(&self) -> &AccountId {
+	fn sender(&self) -> &Self::Sender {
-		&self.address
+		&self.inner.signed
 	}
 
 	fn mem_usage(&self) -> usize {
@@ -244,7 +217,7 @@ impl transaction_pool::VerifiedTransaction for VerifiedTransaction {
 #[derive(Debug)]
 pub struct Scoring;
 
-impl transaction_pool::Scoring<VerifiedTransaction> for Scoring {
+impl txpool::Scoring<VerifiedTransaction> for Scoring {
 	type Score = u64;
 	type Event = ();
 
@@ -258,7 +231,7 @@ impl transaction_pool::Scoring<VerifiedTransaction> for Scoring {
 
 	fn update_scores(
 		&self,
-		xts: &[Transaction<VerifiedTransaction>],
+		xts: &[txpool::Transaction<VerifiedTransaction>],
 		scores: &mut [Self::Score],
 		_change: Change<()>
 	) {
@@ -276,7 +249,7 @@ impl transaction_pool::Scoring<VerifiedTransaction> for Scoring {
 /// Readiness evaluator for polkadot transactions.
 pub struct Ready<'a, T: 'a + PolkadotApi> {
 	at_block: T::CheckedBlockId,
-	api_handle: &'a T,
+	api: &'a T,
 	known_indices: HashMap<AccountId, ::primitives::Index>,
 }
 
@@ -284,7 +257,7 @@ impl<'a, T: 'a + PolkadotApi> Clone for Ready<'a, T> {
 	fn clone(&self) -> Self {
 		Ready {
 			at_block: self.at_block.clone(),
-			api_handle: self.api_handle,
+			api: self.api,
 			known_indices: self.known_indices.clone(),
 		}
 	}
@@ -293,106 +266,85 @@ impl<'a, T: 'a + PolkadotApi> Clone for Ready<'a, T> {
 impl<'a, T: 'a + PolkadotApi> Ready<'a, T> {
 	/// Create a new readiness evaluator at the given block. Requires that
 	/// the ID has already been checked for local corresponding and available state.
-	pub fn create(at: T::CheckedBlockId, client: &'a T) -> Self {
+	pub fn create(at: T::CheckedBlockId, api: &'a T) -> Self {
 		Ready {
 			at_block: at,
-			api_handle: client,
+			api,
 			known_indices: HashMap::new(),
 		}
 	}
 }
 
-impl<'a, T: 'a + PolkadotApi> transaction_pool::Ready<VerifiedTransaction> for Ready<'a, T> {
+impl<'a, T: 'a + PolkadotApi> txpool::Ready<VerifiedTransaction> for Ready<'a, T> {
 	fn is_ready(&mut self, xt: &VerifiedTransaction) -> Readiness {
 		let sender = xt.inner.signed;
 		trace!(target: "transaction-pool", "Checking readiness of {} (from {})", xt.hash, Hash::from(sender));
 
 		// TODO: find a way to handle index error properly -- will need changes to
 		// transaction-pool trait.
-		let (api_handle, at_block) = (&self.api_handle, &self.at_block);
+		let (api, at_block) = (&self.api, &self.at_block);
 		let next_index = self.known_indices.entry(sender)
-			.or_insert_with(|| api_handle.index(at_block, sender).ok().unwrap_or_else(Bounded::max_value));
+			.or_insert_with(|| api.index(at_block, sender).ok().unwrap_or_else(Bounded::max_value));
 
 		trace!(target: "transaction-pool", "Next index for sender is {}; xt index is {}", next_index, xt.inner.index);
 
-		match xt.inner.index.cmp(&next_index) {
+		let result = match xt.inner.index.cmp(&next_index) {
 			Ordering::Greater => Readiness::Future,
 			Ordering::Equal => Readiness::Ready,
-			Ordering::Less => Readiness::Stale,	// TODO: this is not "stalled" but rather stale and can be discarded.
+			Ordering::Less => Readiness::Stale,
-		}
+		};
+
+		// remember to increment `next_index`
+		*next_index = next_index.saturating_add(1);
+
+		result
+	}
+}
+
+pub struct Verifier;
+
+impl txpool::Verifier<Extrinsic> for Verifier {
+	type VerifiedTransaction = VerifiedTransaction;
+	type Error = Error;
+
+	fn verify_transaction(&self, xt: Extrinsic) -> Result<Self::VerifiedTransaction> {
+		info!("Extrinsic submitted: {}", HexDisplay::from(&xt.0));
+		let uxt = xt.using_encoded(|ref mut s| UncheckedExtrinsic::decode(s))
+			.ok_or_else(|| ErrorKind::InvalidExtrinsicFormat)?;
+		info!("Correctly formatted: {:?}", uxt);
+		VerifiedTransaction::create(uxt)
 	}
 }
 
 /// The polkadot transaction pool.
 ///
-/// Wraps a `transaction-pool::Pool`.
+/// Wraps a `extrinsic_pool::Pool`.
 pub struct TransactionPool {
-	inner: transaction_pool::Pool<VerifiedTransaction, Scoring>,
+	inner: Pool<Verifier, Scoring, Error>,
-	insertion_index: u64, // TODO: use AtomicU64 when it stabilizes
 }
 
 impl TransactionPool {
 	/// Create a new transaction pool.
 	pub fn new(options: Options) -> Self {
 		TransactionPool {
-			inner: Pool::new(NoopListener, Scoring, options),
+			inner: Pool::new(options, Verifier, Scoring),
-			insertion_index: 0,
 		}
 	}
 
-	/// Verify and import a transaction into the pool.
+	pub fn import_unchecked_extrinsic(&self, uxt: UncheckedExtrinsic) -> Result<Arc<VerifiedTransaction>> {
-	pub fn import(&mut self, xt: UncheckedExtrinsic) -> Result<Arc<VerifiedTransaction>> {
+		Ok(self.inner.import(VerifiedTransaction::create(uxt)?)?)
-		let insertion_index = self.insertion_index;
-		self.insertion_index += 1;
-
-		let verified = VerifiedTransaction::create(xt, insertion_index)?;
-
-		info!("Extrinsic verified {:?}. Importing...", verified);
-
-		// TODO: just use a foreign link when the error type is made public.
-		let hash = verified.hash.clone();
-		self.inner.import(verified)
-			.map_err(|e|
-				match e {
-					// TODO: make error types public in transaction_pool. For now just treat all errors as AlreadyImported
-					_ => ErrorKind::AlreadyImported(hash),
-					// transaction_pool::error::AlreadyImported(h) => ErrorKind::AlreadyImported(h),
-					// e => ErrorKind::Import(Box::new(e)),
-				})
-			.map_err(Into::into)
 	}
+}
 
-	/// Clear the pool.
+impl Deref for TransactionPool {
-	pub fn clear(&mut self) {
+	type Target = Pool<Verifier, Scoring, Error>;
-		self.inner.clear();
-	}
 
-	/// Remove from the pool.
+	fn deref(&self) -> &Self::Target {
-	pub fn remove(&mut self, hash: &Hash, is_valid: bool) -> Option<Arc<VerifiedTransaction>> {
+		&self.inner
-		self.inner.remove(hash, is_valid)
-	}
-
-	/// Cull transactions from the queue.
-	pub fn cull<T: PolkadotApi>(&mut self, senders: Option<&[AccountId]>, ready: Ready<T>) -> usize {
-		self.inner.cull(senders, ready)
-	}
-
-	/// Get an iterator of pending transactions.
-	pub fn pending<'a, T: 'a + PolkadotApi>(&'a self, ready: Ready<'a, T>) -> PendingIterator<'a, T> {
-		self.inner.pending(ready)
-	}
-
-	/// Get the full status of the queue (including readiness)
-	pub fn status<T: PolkadotApi>(&self, ready: Ready<T>) -> Status {
-		self.inner.status(ready)
-	}
-
-	/// Returns light status of the pool.
-	pub fn light_status(&self) -> LightStatus {
-		self.inner.light_status()
 	}
 }
 
 #[cfg(test)]
 mod tests {
 }
+