Tagged transaction queue integration (#893)

* Make the graph generic. * Adapting pool API for the graph. * Merge pool & graph. * Restructure. * Fix test of transaction pool. * Get rid of node/transaction-pool. * Compilation fixes. * Test7 * Fix compilation of tests. * Revert runtime changes. * Add validate_transaction to test-runtime. * Fix RPC tests. * Add clearing of the old transactions. * Trigger pool events. * Use new queue API. * Fix wasm build, re-export Hasher. * No warning if validate transaction fails. * Get rid of Into<u64> and use As
2026-05-30 00:01:03 +00:00 · 2018-10-12 13:09:35 +02:00
parent 2404d3c89f
commit 671b0e0007
48 changed files with 1234 additions and 1524 deletions
@@ -1598,7 +1598,6 @@ dependencies = [
 "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
 "node-primitives 0.1.0",
 "node-runtime 0.1.0",
- "node-transaction-pool 0.1.0",
 "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "rhododendron 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1608,6 +1607,7 @@ dependencies = [
 "substrate-client 0.1.0",
 "substrate-keyring 0.1.0",
 "substrate-primitives 0.1.0",
+ "substrate-transaction-pool 0.1.0",
 "tokio 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@@ -1715,7 +1715,6 @@ dependencies = [
 "node-network 0.1.0",
 "node-primitives 0.1.0",
 "node-runtime 0.1.0",
- "node-transaction-pool 0.1.0",
 "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "rhododendron 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1731,23 +1730,8 @@ dependencies = [
 "substrate-service-test 0.3.0",
 "substrate-telemetry 0.3.0",
 "substrate-test-client 0.1.0",
- "tokio 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "node-transaction-pool"
-version = "0.1.0"
-dependencies = [
- "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "node-primitives 0.1.0",
- "node-runtime 0.1.0",
- "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "sr-primitives 0.1.0",
- "substrate-client 0.1.0",
- "substrate-keyring 0.1.0",
- "substrate-primitives 0.1.0",
 "substrate-transaction-pool 0.1.0",
+ "tokio 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -3107,6 +3091,7 @@ version = "0.1.0"
 dependencies = [
 "assert_matches 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hex-literal 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "jsonrpc-core 8.0.2 (git+https://github.com/paritytech/jsonrpc.git)",
 "jsonrpc-macros 8.0.1 (git+https://github.com/paritytech/jsonrpc.git)",
 "jsonrpc-pubsub 8.0.1 (git+https://github.com/paritytech/jsonrpc.git)",
@@ -3275,7 +3260,11 @@ name = "substrate-transaction-graph"
 version = "0.1.0"
 dependencies = [
 "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
 "sr-primitives 0.1.0",
 ]

@@ -3288,12 +3277,12 @@ dependencies = [
 "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
 "sr-primitives 0.1.0",
+ "substrate-client 0.1.0",
 "substrate-keyring 0.1.0",
+ "substrate-primitives 0.1.0",
 "substrate-test-client 0.1.0",
- "transaction-pool 1.13.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "substrate-transaction-graph 0.1.0",
 ]

 [[package]]
@@ -3686,30 +3675,11 @@ dependencies = [
 "tokio-reactor 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

-[[package]]
-name = "trace-time"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "traitobject"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"

-[[package]]
-name = "transaction-pool"
-version = "1.13.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "trace-time 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "trie-bench"
 version = "0.9.0"
@@ -4391,9 +4361,7 @@ dependencies = [
 "checksum tokio-tls 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "772f4b04e560117fe3b0a53e490c16ddc8ba6ec437015d91fa385564996ed913"
 "checksum tokio-udp 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "137bda266504893ac4774e0ec4c2108f7ccdbcb7ac8dced6305fe9e4e0b5041a"
 "checksum tokio-uds 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "424c1ed15a0132251813ccea50640b224c809d6ceafb88154c1a8775873a0e89"
-"checksum trace-time 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5aea07da6582e957c6e737eeb63a5af79e648eeeaaaba8fd9a417f1124bafa41"
 "checksum traitobject 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "efd1f82c56340fdf16f2a953d7bda4f8fdffba13d93b00844c25572110b26079"
-"checksum transaction-pool 1.13.3 (registry+https://github.com/rust-lang/crates.io-index)" = "e5866e5126b14358f1d7af4bf51a0be677a363799b90e655edcec8254edef1d2"
 "checksum trie-bench 0.9.0 (git+https://github.com/paritytech/trie)" = "<none>"
 "checksum trie-db 0.9.0 (git+https://github.com/paritytech/trie)" = "<none>"
 "checksum trie-root 0.9.0 (git+https://github.com/paritytech/trie)" = "<none>"
@@ -36,8 +36,8 @@ members = [
 	"core/sr-sandbox",
 	"core/sr-std",
 	"core/sr-version",
-	"core/transaction-graph",
 	"core/transaction-pool",
+	"core/transaction-pool/graph",
 	"srml/support",
 	"srml/balances",
 	"srml/consensus",
@@ -69,7 +69,6 @@ members = [
 	"node/primitives",
 	"node/runtime",
 	"node/service",
-	"node/transaction-pool",
 	"subkey",
 ]
 exclude = [
@@ -58,7 +58,7 @@ pub fn start<C>(service: &Service<C>, exit: ::exit_future::Exit, handle: TaskExe
 				(SyncState::Downloading, Some(n)) => (format!("Syncing{}", speed()), format!(", target=#{}", n)),
 			};
 			last_number = Some(best_number);
-			let txpool_status = txpool.light_status();
+			let txpool_status = txpool.status();
 			info!(
 				target: "substrate",
 				"{}{} ({} peers), best: #{} ({})",
@@ -81,7 +81,7 @@ pub fn start<C>(service: &Service<C>, exit: ::exit_future::Exit, handle: TaskExe
 				"peers" => num_peers,
 				"height" => best_number,
 				"best" => ?hash,
-				"txcount" => txpool_status.transaction_count,
+				"txcount" => txpool_status.ready,
 				"cpu" => cpu_usage,
 				"memory" => memory
 			);
@@ -100,8 +100,8 @@ pub fn start<C>(service: &Service<C>, exit: ::exit_future::Exit, handle: TaskExe

 	let txpool = service.transaction_pool();
 	let display_txpool_import = txpool.import_notification_stream().for_each(move |_| {
-		let status = txpool.light_status();
-		telemetry!("txpool.import"; "mem_usage" => status.mem_usage, "count" => status.transaction_count, "sender" => status.senders);
+		let status = txpool.status();
+		telemetry!("txpool.import"; "ready" => status.ready, "future" => status.future);
 		Ok(())
 	});

@@ -21,7 +21,11 @@ use error::{Error, ErrorKind};
 use futures::sync::mpsc;
 use parking_lot::{Mutex, RwLock};
 use primitives::AuthorityId;
-use runtime_primitives::{bft::Justification, generic::{BlockId, SignedBlock, Block as RuntimeBlock}};
+use runtime_primitives::{
+	bft::Justification,
+	generic::{BlockId, SignedBlock, Block as RuntimeBlock},
+	transaction_validity::{TransactionValidity, TransactionTag},
+};
 use runtime_primitives::traits::{Block as BlockT, Header as HeaderT, Zero, As, NumberFor, CurrentHeight, BlockNumberToHash};
 use runtime_primitives::{ApplyResult, BuildStorage};
 use runtime_api as api;
@@ -158,6 +162,8 @@ pub struct BlockImportNotification<Block: BlockT> {
 	pub header: Block::Header,
 	/// Is this the new best block.
 	pub is_new_best: bool,
+	/// Tags provided by transactions imported in that block.
+	pub tags: Vec<TransactionTag>,
 }

 /// Summary of a finalized block.
@@ -539,6 +545,30 @@ impl<B, E, Block> Client<B, E, Block> where
 		result
 	}

+	// TODO [ToDr] Optimize and re-use tags from the pool.
+	fn transaction_tags(&self, at: Block::Hash, body: &Option<Vec<Block::Extrinsic>>) -> error::Result<Vec<TransactionTag>> {
+		let id = BlockId::Hash(at);
+		Ok(match body {
+			None => vec![],
+			Some(ref extrinsics) => {
+				let mut tags = vec![];
+				for tx in extrinsics {
+					let tx = api::TaggedTransactionQueue::validate_transaction(self, &id, &tx)?;
+					match tx {
+						TransactionValidity::Valid(_, _, mut provides, ..) => {
+							tags.append(&mut provides);
+						},
+						// silently ignore invalid extrinsics,
+						// cause they might just be inherent
+						_ => {}
+					}
+
+				}
+				tags
+			},
+		})
+	}
+
 	fn execute_and_import_block(
 		&self,
 		origin: BlockOrigin,
@@ -574,6 +604,7 @@ impl<B, E, Block> Client<B, E, Block> where
 			self.apply_finality(parent_hash, last_best, make_notifications)?;
 		}

+		let tags = self.transaction_tags(parent_hash, &body)?;
 		let mut transaction = self.backend.begin_operation(BlockId::Hash(parent_hash))?;
 		let (storage_update, changes_update, storage_changes) = match transaction.state()? {
 			Some(transaction_state) => {
@@ -659,6 +690,7 @@ impl<B, E, Block> Client<B, E, Block> where
 				origin,
 				header,
 				is_new_best,
+				tags,
 			};

 			self.import_notification_sinks.lock()
@@ -114,6 +114,7 @@ pub use self::uint::U256;
 pub use authority_id::AuthorityId;
 pub use changes_trie::ChangesTrieConfiguration;

+pub use hash_db::Hasher;
 // Switch back to Blake after PoC-3 is out
 // pub use self::hasher::blake::BlakeHasher;
 pub use self::hasher::blake2::Blake2Hasher;
@@ -23,3 +23,4 @@ tokio = "0.1.7"
 assert_matches = "1.1"
 substrate-test-client = { path = "../test-client" }
 rustc-hex = "2.0"
+hex-literal = "0.1"
@@ -17,14 +17,14 @@
 //! Authoring RPC module errors.

 use client;
-use transaction_pool;
+use transaction_pool::txpool;
 use rpc;

 use errors;

 error_chain! {
 	links {
-		Pool(transaction_pool::Error, transaction_pool::ErrorKind) #[doc = "Pool error"];
+		Pool(txpool::error::Error, txpool::error::ErrorKind) #[doc = "Pool error"];
 		Client(client::error::Error, client::error::ErrorKind) #[doc = "Client error"];
 	}
 	errors {
@@ -21,15 +21,15 @@ use std::sync::Arc;
 use client::{self, Client};
 use codec::Decode;
 use transaction_pool::{
-	Pool,
-	IntoPoolError,
-	ChainApi as PoolChainApi,
-	watcher::Status,
-	VerifiedTransaction,
-	AllExtrinsics,
-	ExHash,
-	ExtrinsicFor,
-	HashOf,
+	txpool::{
+		ChainApi as PoolChainApi,
+		BlockHash,
+		ExHash,
+		ExtrinsicFor,
+		IntoPoolError,
+		Pool,
+		watcher::Status,
+	},
 };
 use jsonrpc_macros::pubsub;
 use jsonrpc_pubsub::SubscriptionId;
@@ -103,7 +103,7 @@ impl<B, E, P> Author<B, E, P> where
 	}
 }

-impl<B, E, P> AuthorApi<ExHash<P>, HashOf<P::Block>, ExtrinsicFor<P>, AllExtrinsics<P>> for Author<B, E, P> where
+impl<B, E, P> AuthorApi<ExHash<P>, BlockHash<P>, ExtrinsicFor<P>, Vec<ExtrinsicFor<P>>> for Author<B, E, P> where
 	B: client::backend::Backend<<P as PoolChainApi>::Block, Blake2Hasher> + Send + Sync + 'static,
 	E: client::CallExecutor<<P as PoolChainApi>::Block, Blake2Hasher> + Send + Sync + 'static,
 	P: PoolChainApi + Sync + Send + 'static,
@@ -124,14 +124,13 @@ impl<B, E, P> AuthorApi<ExHash<P>, HashOf<P::Block>, ExtrinsicFor<P>, AllExtrins
 				.map(Into::into)
 				.unwrap_or_else(|e| error::ErrorKind::Verification(Box::new(e)).into())
 			)
-			.map(|ex| ex.hash().clone())
 	}

-	fn pending_extrinsics(&self) -> Result<AllExtrinsics<P>> {
-		Ok(self.pool.all())
+	fn pending_extrinsics(&self) -> Result<Vec<ExtrinsicFor<P>>> {
+		Ok(self.pool.all(usize::max_value()))
 	}

-	fn watch_extrinsic(&self, _metadata: Self::Metadata, subscriber: pubsub::Subscriber<Status<ExHash<P>, HashOf<P::Block>>>, xt: Bytes) {
+	fn watch_extrinsic(&self, _metadata: Self::Metadata, subscriber: pubsub::Subscriber<Status<ExHash<P>, BlockHash<P>>>, xt: Bytes) {
 		let submit = || -> Result<_> {
 			let best_block_hash = self.client.info()?.chain.best_hash;
 			let dxt = <<P as PoolChainApi>::Block as traits::Block>::Extrinsic::decode(&mut &xt[..]).ok_or(error::Error::from(error::ErrorKind::BadFormat))?;
@@ -16,126 +16,66 @@

 use super::*;

-use std::{sync::Arc, result::Result};
+use std::sync::Arc;
 use codec::Encode;
-use transaction_pool::{VerifiedTransaction, scoring, Transaction, ChainApi, Error as PoolError,
-	Readiness, ExtrinsicFor, VerifiedFor};
-use test_client::runtime::{Block, Extrinsic, Transfer};
+use transaction_pool::{
+	txpool::Pool,
+	ChainApi,
+};
+use primitives::H256;
+use test_client::keyring::Keyring;
+use test_client::runtime::{Extrinsic, Transfer};
 use test_client;
 use tokio::runtime;
-use runtime_primitives::{traits, generic::BlockId};

-#[derive(Clone, Debug)]
-pub struct Verified
-{
-	sender: u64,
-	hash: u64,
-}
-
-impl VerifiedTransaction for Verified {
-	type Hash = u64;
-	type Sender = u64;
-
-	fn hash(&self) -> &Self::Hash { &self.hash }
-	fn sender(&self) -> &Self::Sender { &self.sender }
-	fn mem_usage(&self) -> usize { 256 }
-}
-
-struct TestApi;
-
-impl ChainApi for TestApi {
-	type Block = Block;
-	type Hash = u64;
-	type Sender = u64;
-	type Error = PoolError;
-	type VEx = Verified;
-	type Score = u64;
-	type Event = ();
-	type Ready = ();
-
-	fn latest_hash(&self) -> <Block as traits::Block>::Hash {
-		1.into()
-	}
-
-	fn verify_transaction(&self, _at: &BlockId<Block>, uxt: &ExtrinsicFor<Self>) -> Result<Self::VEx, Self::Error> {
-		Ok(Verified {
-			sender: uxt.transfer.from[31] as u64,
-			hash: uxt.transfer.nonce,
-		})
-	}
-
-	fn is_ready(&self, _at: &BlockId<Block>, _c: &mut Self::Ready, _xt: &VerifiedFor<Self>) -> Readiness {
-		Readiness::Ready
-	}
-
-	fn ready(&self) -> Self::Ready { }
-
-	fn compare(old: &VerifiedFor<Self>, other: &VerifiedFor<Self>) -> ::std::cmp::Ordering {
-		old.verified.hash().cmp(&other.verified.hash())
-	}
-
-	fn choose(_old: &VerifiedFor<Self>, _new: &VerifiedFor<Self>) -> scoring::Choice {
-		scoring::Choice::ReplaceOld
-	}
-
-	fn update_scores(xts: &[Transaction<VerifiedFor<Self>>], scores: &mut [Self::Score], _change: scoring::Change<()>) {
-		for i in 0..xts.len() {
-			scores[i] = xts[i].verified.sender
-		}
-	}
-
-	fn should_replace(_old: &VerifiedFor<Self>, _new: &VerifiedFor<Self>) -> scoring::Choice {
-		scoring::Choice::ReplaceOld
-	}
-}
-
-type DummyTxPool = Pool<TestApi>;
-
-fn uxt(sender: u64, hash: u64) -> Extrinsic {
-	Extrinsic {
-		signature: Default::default(),
-		transfer: Transfer {
-			amount: Default::default(),
-			nonce: hash,
-			from: From::from(sender),
-			to: Default::default(),
-		}
-	}
+fn uxt(sender: Keyring, nonce: u64) -> Extrinsic {
+	let tx = Transfer {
+		amount: Default::default(),
+		nonce,
+		from: sender.to_raw_public().into(),
+		to: Default::default(),
+	};
+	let signature = Keyring::from_raw_public(tx.from.0).unwrap().sign(&tx.encode()).into();
+	Extrinsic { transfer: tx, signature }
 }

 #[test]
 fn submit_transaction_should_not_cause_error() {
 	let runtime = runtime::Runtime::new().unwrap();
+	let client = Arc::new(test_client::new());
 	let p = Author {
-		client: Arc::new(test_client::new()),
-		pool: Arc::new(DummyTxPool::new(Default::default(), TestApi)),
+		client: client.clone(),
+		pool: Arc::new(Pool::new(Default::default(), ChainApi::new(client))),
 		subscriptions: Subscriptions::new(runtime.executor()),
 	};
+	let h: H256 = hex!("e10ad66bce51ef3e2a1167934ce3740d2d8c703810f9b314e89f2e783f75e826").into();

 	assert_matches!(
-		AuthorApi::submit_extrinsic(&p, uxt(5, 1).encode().into()),
-		Ok(1)
+		AuthorApi::submit_extrinsic(&p, uxt(Keyring::Alice, 1).encode().into()),
+		Ok(h2) if h == h2
 	);
 	assert!(
-		AuthorApi::submit_extrinsic(&p, uxt(5, 1).encode().into()).is_err()
+		AuthorApi::submit_extrinsic(&p, uxt(Keyring::Alice, 1).encode().into()).is_err()
 	);
 }

 #[test]
 fn submit_rich_transaction_should_not_cause_error() {
 	let runtime = runtime::Runtime::new().unwrap();
+	let client = Arc::new(test_client::new());
 	let p = Author {
-		client: Arc::new(test_client::new()),
-		pool: Arc::new(DummyTxPool::new(Default::default(), TestApi)),
+		client: client.clone(),
+		pool: Arc::new(Pool::new(Default::default(), ChainApi::new(client.clone()))),
 		subscriptions: Subscriptions::new(runtime.executor()),
 	};
+	let h: H256 = hex!("fccc48291473c53746cd267cf848449edd7711ee6511fba96919d5f9f4859e4f").into();

 	assert_matches!(
-		AuthorApi::submit_rich_extrinsic(&p, uxt(5, 0)),
-		Ok(0)
+		AuthorApi::submit_rich_extrinsic(&p, uxt(Keyring::Alice, 0)),
+		Ok(h2) if h == h2
 	);
 	assert!(
-		AuthorApi::submit_rich_extrinsic(&p, uxt(5, 0)).is_err()
+		AuthorApi::submit_rich_extrinsic(&p, uxt(Keyring::Alice, 0)).is_err()
 	);
 }

@@ -143,40 +83,52 @@ fn submit_rich_transaction_should_not_cause_error() {
 fn should_watch_extrinsic() {
 	//given
 	let mut runtime = runtime::Runtime::new().unwrap();
-	let pool = Arc::new(DummyTxPool::new(Default::default(), TestApi));
+	let client = Arc::new(test_client::new());
+	let pool = Arc::new(Pool::new(Default::default(), ChainApi::new(client.clone())));
 	let p = Author {
-		client: Arc::new(test_client::new()),
+		client,
 		pool: pool.clone(),
 		subscriptions: Subscriptions::new(runtime.executor()),
 	};
 	let (subscriber, id_rx, data) = ::jsonrpc_macros::pubsub::Subscriber::new_test("test");

 	// when
-	p.watch_extrinsic(Default::default(), subscriber, uxt(5, 5).encode().into());
+	p.watch_extrinsic(Default::default(), subscriber, uxt(Keyring::Alice, 0).encode().into());

 	// then
 	assert_eq!(runtime.block_on(id_rx), Ok(Ok(1.into())));
 	// check notifications
-	AuthorApi::submit_rich_extrinsic(&p, uxt(5, 1)).unwrap();
+	let replacement = {
+		let tx = Transfer {
+			amount: 5,
+			nonce: 0,
+			from: Keyring::Alice.to_raw_public().into(),
+			to: Default::default(),
+		};
+		let signature = Keyring::from_raw_public(tx.from.0).unwrap().sign(&tx.encode()).into();
+		Extrinsic { transfer: tx, signature }
+	};
+	AuthorApi::submit_rich_extrinsic(&p, replacement).unwrap();
 	assert_eq!(
 		runtime.block_on(data.into_future()).unwrap().0,
-		Some(r#"{"jsonrpc":"2.0","method":"test","params":{"result":{"usurped":1},"subscription":1}}"#.into())
+		Some(r#"{"jsonrpc":"2.0","method":"test","params":{"result":{"usurped":"0xed454dcee51431679c2559403187a56567fded1fc50b6ae3aada87c1d412df5c"},"subscription":1}}"#.into())
 	);
 }

 #[test]
 fn should_return_pending_extrinsics() {
 	let runtime = runtime::Runtime::new().unwrap();
-	let pool = Arc::new(DummyTxPool::new(Default::default(), TestApi));
+	let client = Arc::new(test_client::new());
+	let pool = Arc::new(Pool::new(Default::default(), ChainApi::new(client.clone())));
 	let p = Author {
-		client: Arc::new(test_client::new()),
+		client,
 		pool: pool.clone(),
 		subscriptions: Subscriptions::new(runtime.executor()),
 	};
-	let ex = uxt(5, 1);
+	let ex = uxt(Keyring::Alice, 0);
 	AuthorApi::submit_rich_extrinsic(&p, ex.clone()).unwrap();
 	assert_matches!(
 		p.pending_extrinsics(),
-		Ok(ref expected) if expected.get(&5) == Some(&vec![ex])
+		Ok(ref expected) if expected == &vec![ex]
 	);
 }
@@ -42,6 +42,9 @@ extern crate log;
 #[macro_use]
 extern crate assert_matches;
 #[cfg(test)]
+#[macro_use]
+extern crate hex_literal;
+#[cfg(test)]
 extern crate substrate_test_client as test_client;
 #[cfg(test)]
 extern crate rustc_hex;
@@ -28,7 +28,7 @@ use client::{self, Client};
 use {error, Service};
 use network::{self, OnDemand};
 use substrate_executor::{NativeExecutor, NativeExecutionDispatch};
-use transaction_pool::{self, Options as TransactionPoolOptions, Pool as TransactionPool};
+use transaction_pool::txpool::{self, Options as TransactionPoolOptions, Pool as TransactionPool};
 use runtime_primitives::{traits::Block as BlockT, traits::Header as HeaderT, BuildStorage};
 use config::Configuration;
 use primitives::{Blake2Hasher};
@@ -105,7 +105,7 @@ pub type ComponentClient<C> = Client<
 pub type ComponentBlock<C> = <<C as Components>::Factory as ServiceFactory>::Block;

 /// Extrinsic hash type for `Components`
-pub type ComponentExHash<C> = <<C as Components>::TransactionPoolApi as transaction_pool::ChainApi>::Hash;
+pub type ComponentExHash<C> = <<C as Components>::TransactionPoolApi as txpool::ChainApi>::Hash;

 /// Extrinsic type.
 pub type ComponentExtrinsic<C> = <ComponentBlock<C> as BlockT>::Extrinsic;
@@ -128,9 +128,9 @@ pub trait ServiceFactory: 'static + Sized {
 	/// Chain runtime.
 	type RuntimeDispatch: NativeExecutionDispatch + Send + Sync + 'static;
 	/// Extrinsic pool backend type for the full client.
-	type FullTransactionPoolApi: transaction_pool::ChainApi<Hash = Self::ExtrinsicHash, Block = Self::Block> + Send + 'static;
+	type FullTransactionPoolApi: txpool::ChainApi<Hash = Self::ExtrinsicHash, Block = Self::Block> + Send + 'static;
 	/// Extrinsic pool backend type for the light client.
-	type LightTransactionPoolApi: transaction_pool::ChainApi<Hash = Self::ExtrinsicHash, Block = Self::Block> + 'static;
+	type LightTransactionPoolApi: txpool::ChainApi<Hash = Self::ExtrinsicHash, Block = Self::Block> + 'static;
 	/// Genesis configuration for the runtime.
 	type Genesis: RuntimeGenesis;
 	/// Other configuration for service members.
@@ -169,7 +169,7 @@ pub trait Components: 'static {
 	/// Client executor.
 	type Executor: 'static + client::CallExecutor<FactoryBlock<Self::Factory>, Blake2Hasher> + Send + Sync;
 	/// Extrinsic pool type.
-	type TransactionPoolApi: 'static + transaction_pool::ChainApi<
+	type TransactionPoolApi: 'static + txpool::ChainApi<
 		Hash = <Self::Factory as ServiceFactory>::ExtrinsicHash,
 		Block = FactoryBlock<Self::Factory>
 	>;
@@ -39,7 +39,7 @@ pub struct Configuration<C, G: Serialize + DeserializeOwned + BuildStorage> {
 	/// Node roles.
 	pub roles: Roles,
 	/// Extrinsic pool configuration.
-	pub transaction_pool: transaction_pool::Options,
+	pub transaction_pool: transaction_pool::txpool::Options,
 	/// Network configuration.
 	pub network: NetworkConfiguration,
 	/// Path to key files.
@@ -113,7 +113,7 @@ pub fn platform() -> String {
 	let env_dash = if env.is_empty() { "" } else { "-" };
 	format!("{}-{}{}{}", Target::arch(), Target::os(), env_dash, env)
 }
-	
+
 /// Returns full version string, using supplied version and commit.
 pub fn full_version_from_strs(impl_version: &str, impl_commit: &str) -> String {
 	let commit_dash = if impl_commit.is_empty() { "" } else { "-" };
@@ -75,7 +75,7 @@ use codec::{Encode, Decode};
 pub use self::error::{ErrorKind, Error};
 pub use config::{Configuration, Roles, PruningMode};
 pub use chain_spec::ChainSpec;
-pub use transaction_pool::{Pool as TransactionPool, Options as TransactionPoolOptions, ChainApi, VerifiedTransaction, IntoPoolError};
+pub use transaction_pool::txpool::{self, Pool as TransactionPool, Options as TransactionPoolOptions, ChainApi, IntoPoolError};
 pub use client::ExecutionStrategy;

 pub use components::{ServiceFactory, FullBackend, FullExecutor, LightBackend,
@@ -116,6 +116,8 @@ pub fn new_client<Factory: components::ServiceFactory>(config: FactoryFullConfig
 impl<Components> Service<Components>
 	where
 		Components: components::Components,
+		txpool::ExHash<Components::TransactionPoolApi>: serde::de::DeserializeOwned + serde::Serialize,
+		txpool::ExtrinsicFor<Components::TransactionPoolApi>: serde::de::DeserializeOwned + serde::Serialize,
 {
 	/// Creates a new service.
 	pub fn new(
@@ -196,7 +198,7 @@ impl<Components> Service<Components>
 					if let Some(network) = network.upgrade() {
 						network.on_block_imported(notification.hash, &notification.header);
 					}
-					txpool.cull(&BlockId::hash(notification.hash))
+					txpool.prune_tags(&BlockId::hash(notification.hash), notification.tags)
 						.map_err(|e| warn!("Error removing extrinsics: {:?}", e))?;
 					Ok(())
 				})
@@ -288,7 +290,11 @@ impl<Components> Service<Components>
 			_telemetry: telemetry,
 		})
 	}
+}

+impl<Components> Service<Components> where
+	Components: components::Components,
+{
 	/// Get shared client instance.
 	pub fn client(&self) -> Arc<ComponentClient<Components>> {
 		self.client.clone()
@@ -386,21 +392,13 @@ impl<C: Components> TransactionPoolAdapter<C> {

 impl<C: Components> network::TransactionPool<ComponentExHash<C>, ComponentBlock<C>> for TransactionPoolAdapter<C> {
 	fn transactions(&self) -> Vec<(ComponentExHash<C>, ComponentExtrinsic<C>)> {
-		let best_block_id = match self.best_block_id() {
-			Some(id) => id,
-			None => return vec![],
-		};
-		self.pool.cull_and_get_pending(&best_block_id, |pending| pending
+		self.pool.ready(|pending| pending
 			.map(|t| {
-				let hash = t.hash().clone();
-				let ex: ComponentExtrinsic<C> = t.original.clone();
+				let hash = t.hash.clone();
+				let ex: ComponentExtrinsic<C> = t.data.raw.clone();
 				(hash, ex)
 			})
-			.collect()
-		).unwrap_or_else(|e| {
-			warn!("Error retrieving pending set: {}", e);
-			vec![]
-		})
+			.collect())
 	}

 	fn import(&self, transaction: &ComponentExtrinsic<C>) -> Option<ComponentExHash<C>> {
@@ -412,13 +410,12 @@ impl<C: Components> network::TransactionPool<ComponentExHash<C>, ComponentBlock<
 		let encoded = transaction.encode();
 		if let Some(uxt) = Decode::decode(&mut &encoded[..]) {
 			let best_block_id = self.best_block_id()?;
+			let hash = self.pool.hash_of(&uxt);
 			match self.pool.submit_one(&best_block_id, uxt) {
-				Ok(xt) => Some(*xt.hash()),
+				Ok(hash) => Some(hash),
 				Err(e) => match e.into_pool_error() {
 					Ok(e) => match e.kind() {
-						transaction_pool::ErrorKind::AlreadyImported(hash) =>
-							Some(::std::str::FromStr::from_str(&hash[2..]).map_err(|_| {})
-								.expect("Hash string is always valid")),
+						txpool::error::ErrorKind::AlreadyImported => Some(hash),
 						_ => {
 							debug!("Error adding transaction to the pool: {:?}", e);
 							None
@@ -427,7 +424,7 @@ impl<C: Components> network::TransactionPool<ComponentExHash<C>, ComponentBlock<
 					Err(e) => {
 						debug!("Error converting pool error: {:?}", e);
 						None
-					}
+					},
 				}
 			}
 		} else {
@@ -247,7 +247,7 @@ where
 	let best_block = BlockId::number(first_service.client().info().unwrap().chain.best_number);
 	first_service.transaction_pool().submit_one(&best_block, extrinsic_factory(&first_service)).unwrap();
 	network.run_until_all_full(|_index, service|
-		service.transaction_pool().all().len() == 1
+		service.transaction_pool().all(usize::max_value()).len() == 1
 	);
 }

@@ -25,7 +25,7 @@ pub extern crate parity_codec as codec;
 extern crate sr_version as runtime_version;

 #[doc(hidden)]
-pub use primitives::{traits::Block as BlockT, generic::BlockId, ApplyResult};
+pub use primitives::{traits::Block as BlockT, generic::BlockId, transaction_validity::TransactionValidity, ApplyResult};
 use runtime_version::RuntimeVersion;
 use rstd::vec::Vec;
 #[doc(hidden)]
@@ -485,7 +485,7 @@ decl_apis! {
 /// #[macro_use]
 /// extern crate sr_api as runtime_api;
 ///
-/// use runtime_api::runtime::{Core, OldTxQueue};
+/// use runtime_api::runtime::{Core, TaggedTransactionQueue};
 ///
 /// impl_apis! {
 ///     impl Core<Block, AccountId> for Runtime {
@@ -498,13 +498,10 @@ decl_apis! {
 ///         }
 ///     }
 ///
-///     impl OldTxQueue<AccountId, Index, Address, LookupId> for Runtime {
-///         fn account_nonce(account: AccountId) -> Index {
-///             0
-///         }
-///         fn lookup_address(address: Address) -> Option<LookupId> {
-///             None
-///         }
+///     impl TaggedTransactionQueue<Block> for Runtime {
+///			fn validate_transaction(tx: <Block as BlockT>::Extrinsic) -> TransactionValidity {
+///				unimplemented!()
+///			}
 ///     }
 /// }
 ///
@@ -81,7 +81,6 @@ impl<'a, Number: 'a, Hash: 'a + HashT, DigestItem: 'a> Deserialize<'a> for Heade
 	}
 }

-// TODO [ToDr] Issue with bounds
 impl<Number, Hash, DigestItem> Decode for Header<Number, Hash, DigestItem> where
 	Number: Decode,
 	Hash: HashT,
@@ -200,7 +200,7 @@ mod tests {

 	const DUMMY_FUNCTION: u64 = 0;
 	const DUMMY_ACCOUNTID: u64 = 0;
-	
+
 	type Ex = UncheckedMortalExtrinsic<u64, u64, u64, TestSig>;
 	type CEx = CheckedExtrinsic<u64, u64, u64>;

@@ -78,7 +78,7 @@ pub trait BlockNumberToHash {
 	type BlockNumber: Zero;

 	/// The type of the hash.
-	type Hash;
+	type Hash: Encode;

 	/// Get the hash for a given block number, or `None` if unknown.
 	fn block_number_to_hash(&self, n: Self::BlockNumber) -> Option<Self::Hash>;
@@ -30,8 +30,14 @@ pub type TransactionTag = Vec<u8>;

 /// Information on a transaction's validity and, if valid, on how it relates to other transactions.
 #[derive(Clone, PartialEq, Eq, Encode, Decode)]
+#[cfg_attr(feature = "std", derive(Debug))]
 pub enum TransactionValidity {
 	Invalid,
-	Valid(TransactionPriority, Vec<TransactionTag>, Vec<TransactionTag>, TransactionLongevity),
+	Valid(
+		/* priority: */TransactionPriority,
+		/* requires: */Vec<TransactionTag>,
+		/* provides: */Vec<TransactionTag>,
+		/* longevity: */TransactionLongevity
+	),
 	Unknown,
 }
@@ -55,7 +55,7 @@ use codec::{Encode, Decode};

 use runtime_api::runtime::*;
 use runtime_primitives::traits::{BlindCheckable, BlakeTwo256, Block as BlockT};
-use runtime_primitives::{ApplyResult, Ed25519Signature};
+use runtime_primitives::{ApplyResult, Ed25519Signature, transaction_validity::TransactionValidity};
 use runtime_version::RuntimeVersion;
 pub use primitives::hash::H256;
 use primitives::AuthorityId;
@@ -159,6 +159,7 @@ mod test_api {
 		}
 	}
 }
+
 use test_api::runtime::TestAPI;

 struct Runtime;
@@ -178,6 +179,12 @@ impl_apis! {
 		}
 	}

+	impl TaggedTransactionQueue<Block, TransactionValidity> for Runtime {
+		fn validate_transaction(utx: <Block as BlockT>::Extrinsic) -> TransactionValidity {
+			system::validate_transaction(utx)
+		}
+	}
+
 	impl BlockBuilder<Block, u32, u32> for Runtime {
 		fn initialise_block(header: <Block as BlockT>::Header) {
 			system::initialise_block(header)
@@ -18,14 +18,14 @@
 //! and depositing logs.

 use rstd::prelude::*;
-use runtime_io::{storage_root, enumerated_trie_root, storage_changes_root};
+use runtime_io::{storage_root, enumerated_trie_root, storage_changes_root, twox_128};
 use runtime_support::storage::{self, StorageValue, StorageMap};
 use runtime_primitives::traits::{Hash as HashT, BlakeTwo256, Digest as DigestT};
 use runtime_primitives::generic;
-use runtime_primitives::{ApplyError, ApplyOutcome, ApplyResult};
+use runtime_primitives::{ApplyError, ApplyOutcome, ApplyResult, transaction_validity::TransactionValidity};
 use codec::{KeyedVec, Encode};
 use super::{AccountId, BlockNumber, Extrinsic, H256 as Hash, Block, Header, Digest};
-use primitives::Blake2Hasher;
+use primitives::{Blake2Hasher};
 use primitives::storage::well_known_keys;

 const NONCE_OF: &[u8] = b"nonce:";
@@ -99,6 +99,47 @@ pub fn execute_block(block: Block) {
 	assert!(digest == header.digest, "Header digest items must match that calculated.");
 }

+/// Execute a transaction outside of the block execution function.
+/// This doesn't attempt to validate anything regarding the block.
+pub fn validate_transaction(utx: Extrinsic) -> TransactionValidity {
+	let tx = match check_signature(&utx) {
+		Ok(tx) => tx,
+		Err(_) => return TransactionValidity::Invalid,
+	};
+
+	let nonce_key = tx.from.to_keyed_vec(NONCE_OF);
+	let expected_nonce: u64 = storage::get_or(&nonce_key, 0);
+	if tx.nonce < expected_nonce {
+		return TransactionValidity::Invalid;
+	}
+	if tx.nonce > expected_nonce + 64 {
+		return TransactionValidity::Unknown;
+	}
+
+	let hash = |from: &AccountId, nonce: u64| {
+		twox_128(&nonce.to_keyed_vec(&*from)).to_vec()
+	};
+	let requires = if tx.nonce != expected_nonce && tx.nonce > 0 {
+		let mut deps = Vec::new();
+		deps.push(hash(&tx.from, tx.nonce - 1));
+		deps
+	} else { Vec::new() };
+
+	let provides = {
+		let mut p = Vec::new();
+		p.push(hash(&tx.from, tx.nonce));
+		p
+	};
+
+	TransactionValidity::Valid(
+		/* priority: */tx.amount,
+		requires,
+		provides,
+		/* longevity: */64
+	)
+}
+
+
 /// Execute a transaction outside of the block execution function.
 /// This doesn't attempt to validate anything regarding the block.
 pub fn execute_transaction(utx: Extrinsic) -> ApplyResult {
@@ -135,16 +176,21 @@ pub fn finalise_block() -> Header {
 	}
 }

-fn execute_transaction_backend(utx: &Extrinsic) -> ApplyResult {
+#[inline(always)]
+fn check_signature(utx: &Extrinsic) -> Result<::Transfer, ApplyError> {
 	use runtime_primitives::traits::BlindCheckable;

-	// check signature
 	let utx = match utx.clone().check() {
 		Ok(tx) => tx,
 		Err(_) => return Err(ApplyError::BadSignature),
 	};

-	let tx: ::Transfer = utx.transfer;
+	Ok(utx.transfer)
+}
+
+fn execute_transaction_backend(utx: &Extrinsic) -> ApplyResult {
+	// check signature
+	let tx = check_signature(utx)?;

 	// check nonce
 	let nonce_key = tx.from.to_keyed_vec(NONCE_OF);
@@ -4,16 +4,16 @@ version = "0.1.0"
 authors = ["Parity Technologies <admin@parity.io>"]

 [dependencies]
-serde = "1.0"
-serde_derive = "1.0"
 error-chain = "0.12"
 futures = "0.1"
 log = "0.4"
+parity-codec = "2.0"
 parking_lot = "0.4"
-transaction-pool = "1.13.3"
-sr-primitives = { path = "../../core/sr-primitives" }
+sr-primitives = { path = "../sr-primitives" }
+substrate-client = { path = "../client" }
+substrate-primitives = { path = "../primitives" }
+substrate-transaction-graph = { path = "./graph" }

 [dev-dependencies]
 substrate-test-client = { path = "../../core/test-client" }
 substrate-keyring = { path = "../../core/keyring" }
-parity-codec = "2.0"
@@ -5,5 +5,9 @@ authors = ["Parity Technologies <admin@parity.io>"]

 [dependencies]
 error-chain = "0.12"
+futures = "0.1"
 log = "0.4"
-sr-primitives = { path = "../sr-primitives" }
+parking_lot = "0.4"
+serde = "1.0"
+serde_derive = "1.0"
+sr-primitives = { path = "../../sr-primitives" }
@@ -0,0 +1,13 @@
+
+= transaction-graph
+
+.Summary
+[source, toml]
+----
+include::Cargo.toml[lines=2..5]
+----
+
+.Description
+----
+include::src/lib.rs[tag=description]
+----
@@ -14,6 +14,10 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

+//! A basic version of the dependency graph.
+//!
+//! For a more full-featured pool, have a look at the `pool` module.
+
 use std::{
 	hash,
 	sync::Arc,
@@ -30,11 +34,12 @@ use error;
 use future::{FutureTransactions, WaitingTransaction};
 use ready::ReadyTransactions;

+/// Block number type.
 pub type BlockNumber = u64;

 /// Successful import result.
 #[derive(Debug, PartialEq, Eq)]
-pub enum Imported<Hash> {
+pub enum Imported<Hash, Ex> {
 	/// Transaction was successfuly imported to Ready queue.
 	Ready {
 		/// Hash of transaction that was successfuly imported.
@@ -44,7 +49,7 @@ pub enum Imported<Hash> {
 		/// Transactions that failed to be promoted from the Future queue and are now discarded.
 		failed: Vec<Hash>,
 		/// Transactions removed from the Ready pool (replaced).
-		removed: Vec<Arc<Transaction<Hash>>>,
+		removed: Vec<Arc<Transaction<Hash, Ex>>>,
 	},
 	/// Transaction was successfuly imported to Future queue.
 	Future {
@@ -53,23 +58,34 @@ pub enum Imported<Hash> {
 	}
 }

+impl<Hash, Ex> Imported<Hash, Ex> {
+	/// Returns the hash of imported transaction.
+	pub fn hash(&self) -> &Hash {
+		use self::Imported::*;
+		match *self {
+			Ready { ref hash, .. } => hash,
+			Future { ref hash, .. } => hash,
+		}
+	}
+}
+
 /// Status of pruning the queue.
 #[derive(Debug)]
-pub struct PruneStatus<Hash> {
+pub struct PruneStatus<Hash, Ex> {
 	/// A list of imports that satisfying the tag triggered.
-	pub promoted: Vec<Imported<Hash>>,
+	pub promoted: Vec<Imported<Hash, Ex>>,
 	/// A list of transactions that failed to be promoted and now are discarded.
 	pub failed: Vec<Hash>,
 	/// A list of transactions that got pruned from the ready queue.
-	pub pruned: Vec<Arc<Transaction<Hash>>>,
+	pub pruned: Vec<Arc<Transaction<Hash, Ex>>>,
 }

 /// Immutable transaction
 #[cfg_attr(test, derive(Clone))]
-#[derive(Debug, PartialEq, Eq)]
-pub struct Transaction<Hash> {
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Transaction<Hash, Extrinsic> {
 	/// Raw extrinsic representing that transaction.
-	pub ex: Vec<u8>,
+	pub data: Extrinsic,
 	/// Transaction hash (unique)
 	pub hash: Hash,
 	/// Transaction priority (higher = better)
@@ -92,13 +108,22 @@ pub struct Transaction<Hash> {
 /// as-is for the second time will fail or produce unwanted results.
 /// Most likely it is required to revalidate them and recompute set of
 /// required tags.
-#[derive(Default, Debug)]
-pub struct Pool<Hash: hash::Hash + Eq> {
-	future: FutureTransactions<Hash>,
-	ready: ReadyTransactions<Hash>,
+#[derive(Debug)]
+pub struct BasePool<Hash: hash::Hash + Eq, Ex> {
+	future: FutureTransactions<Hash, Ex>,
+	ready: ReadyTransactions<Hash, Ex>,
 }

-impl<Hash: hash::Hash + Member> Pool<Hash> {
+impl<Hash: hash::Hash + Eq, Ex> Default for BasePool<Hash, Ex> {
+	fn default() -> Self {
+		BasePool {
+			future: Default::default(),
+			ready: Default::default(),
+		}
+	}
+}
+
+impl<Hash: hash::Hash + Member, Ex: ::std::fmt::Debug> BasePool<Hash, Ex> {
 	/// Imports transaction to the pool.
 	///
 	/// The pool consists of two parts: Future and Ready.
@@ -109,8 +134,8 @@ impl<Hash: hash::Hash + Member> Pool<Hash> {
 	pub fn import(
 		&mut self,
 		block_number: BlockNumber,
-		tx: Transaction<Hash>,
-	) -> error::Result<Imported<Hash>> {
+		tx: Transaction<Hash, Ex>,
+	) -> error::Result<Imported<Hash, Ex>> {
 		if self.future.contains(&tx.hash) || self.ready.contains(&tx.hash) {
 			bail!(error::ErrorKind::AlreadyImported)
 		}
@@ -132,7 +157,7 @@ impl<Hash: hash::Hash + Member> Pool<Hash> {
 	/// Imports transaction to ready queue.
 	///
 	/// NOTE the transaction has to have all requirements satisfied.
-	fn import_to_ready(&mut self, block_number: BlockNumber, tx: WaitingTransaction<Hash>) -> error::Result<Imported<Hash>> {
+	fn import_to_ready(&mut self, block_number: BlockNumber, tx: WaitingTransaction<Hash, Ex>) -> error::Result<Imported<Hash, Ex>> {
 		let hash = tx.transaction.hash.clone();
 		let mut promoted = vec![];
 		let mut failed = vec![];
@@ -195,7 +220,7 @@ impl<Hash: hash::Hash + Member> Pool<Hash> {
 	}

 	/// Returns an iterator over ready transactions in the pool.
-	pub fn ready<'a>(&'a self) -> impl Iterator<Item=Arc<Transaction<Hash>>> + 'a {
+	pub fn ready<'a, 'b: 'a>(&'b self) -> impl Iterator<Item=Arc<Transaction<Hash, Ex>>> + 'a {
 		self.ready.get()
 	}

@@ -207,7 +232,7 @@ impl<Hash: hash::Hash + Member> Pool<Hash> {
 	/// they were part of a chain, you may attempt to re-import them later.
 	/// NOTE If you want to remove ready transactions that were already used
 	/// and you don't want them to be stored in the pool use `prune_tags` method.
-	pub fn remove_invalid(&mut self, hashes: &[Hash]) -> Vec<Arc<Transaction<Hash>>> {
+	pub fn remove_invalid(&mut self, hashes: &[Hash]) -> Vec<Arc<Transaction<Hash, Ex>>> {
 		let mut removed = self.ready.remove_invalid(hashes);
 		removed.extend(self.future.remove(hashes).into_iter().map(Arc::new));
 		removed
@@ -219,7 +244,7 @@ impl<Hash: hash::Hash + Member> Pool<Hash> {
 	/// but unlike `remove_invalid`, dependent transactions are not touched.
 	/// Additional transactions from future queue might be promoted to ready if you satisfy tags
 	/// that the pool didn't previously know about.
-	pub fn prune_tags(&mut self, block_number: BlockNumber, tags: impl IntoIterator<Item=Tag>) -> PruneStatus<Hash> {
+	pub fn prune_tags(&mut self, block_number: BlockNumber, tags: impl IntoIterator<Item=Tag>) -> PruneStatus<Hash, Ex> {
 		let mut to_import = vec![];
 		let mut pruned = vec![];

@@ -249,6 +274,22 @@ impl<Hash: hash::Hash + Member> Pool<Hash> {
 			promoted,
 		}
 	}
+
+	/// Get pool status.
+	pub fn status(&self) -> Status {
+		Status {
+			ready: self.ready.len(),
+			future: self.future.len(),
+		}
+	}
+}
+
+/// Pool status
+pub struct Status {
+	/// Number of transactions in the ready queue.
+	pub ready: usize,
+	/// Number of transactions in the future queue.
+	pub future: usize,
 }

 #[cfg(test)]
@@ -257,8 +298,8 @@ mod tests {

 	type Hash = u64;

-	fn pool() -> Pool<Hash> {
-		Pool::default()
+	fn pool() -> BasePool<Hash, Vec<u8>> {
+		BasePool::default()
 	}

 	#[test]
@@ -268,7 +309,7 @@ mod tests {

 		// when
 		pool.import(1, Transaction {
-			ex: vec![1u8],
+			data: vec![1u8],
 			hash: 1u64,
 			priority: 5u64,
 			longevity: 64u64,
@@ -288,7 +329,7 @@ mod tests {

 		// when
 		pool.import(1, Transaction {
-			ex: vec![1u8],
+			data: vec![1u8],
 			hash: 1,
 			priority: 5u64,
 			longevity: 64u64,
@@ -296,7 +337,7 @@ mod tests {
 			provides: vec![vec![1]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![1u8],
+			data: vec![1u8],
 			hash: 1,
 			priority: 5u64,
 			longevity: 64u64,
@@ -317,7 +358,7 @@ mod tests {

 		// when
 		pool.import(1, Transaction {
-			ex: vec![1u8],
+			data: vec![1u8],
 			hash: 1,
 			priority: 5u64,
 			longevity: 64u64,
@@ -327,7 +368,7 @@ mod tests {
 		assert_eq!(pool.ready().count(), 0);
 		assert_eq!(pool.ready.len(), 0);
 		pool.import(1, Transaction {
-			ex: vec![2u8],
+			data: vec![2u8],
 			hash: 2,
 			priority: 5u64,
 			longevity: 64u64,
@@ -347,7 +388,7 @@ mod tests {

 		// when
 		pool.import(1, Transaction {
-			ex: vec![1u8],
+			data: vec![1u8],
 			hash: 1,
 			priority: 5u64,
 			longevity: 64u64,
@@ -355,7 +396,7 @@ mod tests {
 			provides: vec![vec![1]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![3u8],
+			data: vec![3u8],
 			hash: 3,
 			priority: 5u64,
 			longevity: 64u64,
@@ -363,7 +404,7 @@ mod tests {
 			provides: vec![],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![2u8],
+			data: vec![2u8],
 			hash: 2,
 			priority: 5u64,
 			longevity: 64u64,
@@ -371,7 +412,7 @@ mod tests {
 			provides: vec![vec![3], vec![2]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![4u8],
+			data: vec![4u8],
 			hash: 4,
 			priority: 1_000u64,
 			longevity: 64u64,
@@ -382,7 +423,7 @@ mod tests {
 		assert_eq!(pool.ready.len(), 0);

 		let res = pool.import(1, Transaction {
-			ex: vec![5u8],
+			data: vec![5u8],
 			hash: 5,
 			priority: 5u64,
 			longevity: 64u64,
@@ -391,7 +432,7 @@ mod tests {
 		}).unwrap();

 		// then
-		let mut it = pool.ready().into_iter().map(|tx| tx.ex[0]);
+		let mut it = pool.ready().into_iter().map(|tx| tx.data[0]);

 		assert_eq!(it.next(), Some(5));
 		assert_eq!(it.next(), Some(1));
@@ -412,7 +453,7 @@ mod tests {
 		// given
 		let mut pool = pool();
 		pool.import(1, Transaction {
-			ex: vec![1u8],
+			data: vec![1u8],
 			hash: 1,
 			priority: 5u64,
 			longevity: 64u64,
@@ -420,7 +461,7 @@ mod tests {
 			provides: vec![vec![1]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![3u8],
+			data: vec![3u8],
 			hash: 3,
 			priority: 5u64,
 			longevity: 64u64,
@@ -432,7 +473,7 @@ mod tests {

 		// when
 		pool.import(1, Transaction {
-			ex: vec![2u8],
+			data: vec![2u8],
 			hash: 2,
 			priority: 5u64,
 			longevity: 64u64,
@@ -442,7 +483,7 @@ mod tests {

 		// then
 		{
-			let mut it = pool.ready().into_iter().map(|tx| tx.ex[0]);
+			let mut it = pool.ready().into_iter().map(|tx| tx.data[0]);
 			assert_eq!(it.next(), None);
 		}
 		// all transactions occupy the Future queue - it's fine
@@ -450,14 +491,14 @@ mod tests {

 		// let's close the cycle with one additional transaction
 		let res = pool.import(1, Transaction {
-			ex: vec![4u8],
+			data: vec![4u8],
 			hash: 4,
 			priority: 50u64,
 			longevity: 64u64,
 			requires: vec![],
 			provides: vec![vec![0]],
 		}).unwrap();
-		let mut it = pool.ready().into_iter().map(|tx| tx.ex[0]);
+		let mut it = pool.ready().into_iter().map(|tx| tx.data[0]);
 		assert_eq!(it.next(), Some(4));
 		assert_eq!(it.next(), Some(1));
 		assert_eq!(it.next(), Some(3));
@@ -477,7 +518,7 @@ mod tests {
 		// given
 		let mut pool = pool();
 		pool.import(1, Transaction {
-			ex: vec![1u8],
+			data: vec![1u8],
 			hash: 1,
 			priority: 5u64,
 			longevity: 64u64,
@@ -485,7 +526,7 @@ mod tests {
 			provides: vec![vec![1]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![3u8],
+			data: vec![3u8],
 			hash: 3,
 			priority: 5u64,
 			longevity: 64u64,
@@ -497,7 +538,7 @@ mod tests {

 		// when
 		pool.import(1, Transaction {
-			ex: vec![2u8],
+			data: vec![2u8],
 			hash: 2,
 			priority: 5u64,
 			longevity: 64u64,
@@ -507,7 +548,7 @@ mod tests {

 		// then
 		{
-			let mut it = pool.ready().into_iter().map(|tx| tx.ex[0]);
+			let mut it = pool.ready().into_iter().map(|tx| tx.data[0]);
 			assert_eq!(it.next(), None);
 		}
 		// all transactions occupy the Future queue - it's fine
@@ -515,14 +556,14 @@ mod tests {

 		// let's close the cycle with one additional transaction
 		let err = pool.import(1, Transaction {
-			ex: vec![4u8],
+			data: vec![4u8],
 			hash: 4,
 			priority: 1u64, // lower priority than Tx(2)
 			longevity: 64u64,
 			requires: vec![],
 			provides: vec![vec![0]],
 		}).unwrap_err();
-		let mut it = pool.ready().into_iter().map(|tx| tx.ex[0]);
+		let mut it = pool.ready().into_iter().map(|tx| tx.data[0]);
 		assert_eq!(it.next(), None);
 		assert_eq!(pool.ready.len(), 0);
 		assert_eq!(pool.future.len(), 0);
@@ -537,7 +578,7 @@ mod tests {
 		// given
 		let mut pool = pool();
 		pool.import(1, Transaction {
-			ex: vec![5u8],
+			data: vec![5u8],
 			hash: 5,
 			priority: 5u64,
 			longevity: 64u64,
@@ -545,7 +586,7 @@ mod tests {
 			provides: vec![vec![0], vec![4]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![1u8],
+			data: vec![1u8],
 			hash: 1,
 			priority: 5u64,
 			longevity: 64u64,
@@ -553,7 +594,7 @@ mod tests {
 			provides: vec![vec![1]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![3u8],
+			data: vec![3u8],
 			hash: 3,
 			priority: 5u64,
 			longevity: 64u64,
@@ -561,7 +602,7 @@ mod tests {
 			provides: vec![],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![2u8],
+			data: vec![2u8],
 			hash: 2,
 			priority: 5u64,
 			longevity: 64u64,
@@ -569,7 +610,7 @@ mod tests {
 			provides: vec![vec![3], vec![2]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![4u8],
+			data: vec![4u8],
 			hash: 4,
 			priority: 1_000u64,
 			longevity: 64u64,
@@ -578,7 +619,7 @@ mod tests {
 		}).unwrap();
 		// future
 		pool.import(1, Transaction {
-			ex: vec![6u8],
+			data: vec![6u8],
 			hash: 6,
 			priority: 1_000u64,
 			longevity: 64u64,
@@ -603,7 +644,7 @@ mod tests {
 		let mut pool = pool();
 		// future (waiting for 0)
 		pool.import(1, Transaction {
-			ex: vec![5u8],
+			data: vec![5u8],
 			hash: 5,
 			priority: 5u64,
 			longevity: 64u64,
@@ -612,7 +653,7 @@ mod tests {
 		}).unwrap();
 		// ready
 		pool.import(1, Transaction {
-			ex: vec![1u8],
+			data: vec![1u8],
 			hash: 1,
 			priority: 5u64,
 			longevity: 64u64,
@@ -620,7 +661,7 @@ mod tests {
 			provides: vec![vec![1]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![2u8],
+			data: vec![2u8],
 			hash: 2,
 			priority: 5u64,
 			longevity: 64u64,
@@ -628,7 +669,7 @@ mod tests {
 			provides: vec![vec![3]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![3u8],
+			data: vec![3u8],
 			hash: 3,
 			priority: 5u64,
 			longevity: 64u64,
@@ -636,7 +677,7 @@ mod tests {
 			provides: vec![vec![2]],
 		}).unwrap();
 		pool.import(1, Transaction {
-			ex: vec![4u8],
+			data: vec![4u8],
 			hash: 4,
 			priority: 1_000u64,
 			longevity: 64u64,
@@ -14,10 +14,27 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

+//! Transaction pool errors.
+
 use sr_primitives::transaction_validity::TransactionPriority as Priority;

 error_chain! {
 	errors {
+		/// Transaction is not verifiable yet, but might be in the future.
+		UnknownTransactionValidity {
+			description("Runtime cannot determine validity of the transaction yet."),
+			display("Unkown Transaction Validity"),
+		}
+		/// Transaction is invalid
+		InvalidTransaction {
+			description("Runtime check for the transaction failed."),
+			display("Invalid Transaction"),
+		}
+		/// The transaction is temporarily baned
+		TemporarilyBanned {
+			description("Transaction is temporarily banned from importing to the pool."),
+			display("Temporarily Banned"),
+		}
 		/// The transaction is already in the pool.
 		AlreadyImported {
 			description("Transaction is already in the pool."),
@@ -35,3 +52,17 @@ error_chain! {
 		}
 	}
 }
+
+/// Transaction pool error conversion.
+pub trait IntoPoolError: ::std::error::Error + Send + Sized {
+	/// Try to extract original `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) -> ::std::result::Result<Error, Self> { Err(self) }
+}
+
+impl IntoPoolError for Error {
+	fn into_pool_error(self) -> ::std::result::Result<Error, Self> { Ok(self) }
+}
@@ -23,23 +23,23 @@ use sr_primitives::transaction_validity::{
 	TransactionTag as Tag,
 };

-use pool::Transaction;
+use base_pool::Transaction;

 /// Transaction with partially satisfied dependencies.
 #[derive(Debug)]
-pub struct WaitingTransaction<Hash> {
+pub struct WaitingTransaction<Hash, Ex> {
 	/// Transaction details.
-	pub transaction: Transaction<Hash>,
+	pub transaction: Transaction<Hash, Ex>,
 	/// Tags that are required and have not been satisfied yet by other transactions in the pool.
 	pub missing_tags: HashSet<Tag>,
 }

-impl<Hash> WaitingTransaction<Hash> {
+impl<Hash, Ex> WaitingTransaction<Hash, Ex> {
 	/// Creates a new `WaitingTransaction`.
 	///
 	/// Computes the set of missing tags based on the requirements and tags that
 	/// are provided by all transactions in the ready queue.
-	pub fn new(transaction: Transaction<Hash>, provided: &HashMap<Tag, Hash>) -> Self {
+	pub fn new(transaction: Transaction<Hash, Ex>, provided: &HashMap<Tag, Hash>) -> Self {
 		let missing_tags = transaction.requires
 			.iter()
 			.filter(|tag| !provided.contains_key(&**tag))
@@ -68,14 +68,14 @@ impl<Hash> WaitingTransaction<Hash> {
 /// Contains transactions that are still awaiting for some other transactions that
 /// could provide a tag that they require.
 #[derive(Debug)]
-pub struct FutureTransactions<Hash: hash::Hash + Eq> {
+pub struct FutureTransactions<Hash: hash::Hash + Eq, Ex> {
 	/// tags that are not yet provided by any transaction and we await for them
 	wanted_tags: HashMap<Tag, HashSet<Hash>>,
 	/// Transactions waiting for a particular other transaction
-	waiting: HashMap<Hash, WaitingTransaction<Hash>>,
+	waiting: HashMap<Hash, WaitingTransaction<Hash, Ex>>,
 }

-impl<Hash: hash::Hash + Eq> Default for FutureTransactions<Hash> {
+impl<Hash: hash::Hash + Eq, Ex> Default for FutureTransactions<Hash, Ex> {
 	fn default() -> Self {
 		FutureTransactions {
 			wanted_tags: Default::default(),
@@ -91,14 +91,14 @@ every hash from `wanted_tags` is always present in `waiting`;
 qed
 #";

-impl<Hash: hash::Hash + Eq + Clone> FutureTransactions<Hash> {
+impl<Hash: hash::Hash + Eq + Clone, Ex> FutureTransactions<Hash, Ex> {
 	/// Import transaction to Future queue.
 	///
 	/// Only transactions that don't have all their tags satisfied should occupy
 	/// the Future queue.
 	/// As soon as required tags are provided by some other transactions that are ready
 	/// we should remove the transactions from here and move them to the Ready queue.
-	pub fn import(&mut self, tx: WaitingTransaction<Hash>) {
+	pub fn import(&mut self, tx: WaitingTransaction<Hash, Ex>) {
 		assert!(!tx.is_ready(), "Transaction is ready.");
 		assert!(!self.waiting.contains_key(&tx.transaction.hash), "Transaction is already imported.");

@@ -121,7 +121,7 @@ impl<Hash: hash::Hash + Eq + Clone> FutureTransactions<Hash> {
 	///
 	/// Returns (and removes) transactions that became ready after their last tag got
 	/// satisfied and now we can remove them from Future and move to Ready queue.
-	pub fn satisfy_tags<T: AsRef<Tag>>(&mut self, tags: impl IntoIterator<Item=T>) -> Vec<WaitingTransaction<Hash>> {
+	pub fn satisfy_tags<T: AsRef<Tag>>(&mut self, tags: impl IntoIterator<Item=T>) -> Vec<WaitingTransaction<Hash, Ex>> {
 		let mut became_ready = vec![];

 		for tag in tags {
@@ -148,7 +148,7 @@ impl<Hash: hash::Hash + Eq + Clone> FutureTransactions<Hash> {
 	/// Removes transactions for given list of hashes.
 	///
 	/// Returns a list of actually removed transactions.
-	pub fn remove(&mut self, hashes: &[Hash]) -> Vec<Transaction<Hash>> {
+	pub fn remove(&mut self, hashes: &[Hash]) -> Vec<Transaction<Hash, Ex>> {
 		let mut removed = vec![];
 		for hash in hashes {
 			if let Some(waiting_tx) = self.waiting.remove(hash) {
@@ -170,7 +170,6 @@ impl<Hash: hash::Hash + Eq + Clone> FutureTransactions<Hash> {
 	}

 	/// Returns number of transactions in the Future queue.
-	#[cfg(test)]
 	pub fn len(&self) -> usize {
 		self.waiting.len()
 	}
@@ -14,6 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

+// tag::description[]
 //! Generic Transaction Pool
 //!
 //! The pool is based on dependency graph between transactions
@@ -23,23 +24,30 @@
 //!
 //! TODO [ToDr]
 //! - [ ] Longevity handling (remove obsolete transactions periodically)
-//! - [ ] Banning / Future-rotation (once rejected (as invalid) should not be accepted for some time)
 //! - [ ] Multi-threading (getting ready transactions should not block the pool)
+// end::description[]

 #![warn(missing_docs)]
 #![warn(unused_extern_crates)]

+extern crate futures;
+extern crate parking_lot;
 extern crate sr_primitives;

-#[macro_use]
-extern crate error_chain;
+#[macro_use] extern crate error_chain;
+#[macro_use] extern crate log;
+#[macro_use] extern crate serde_derive;

-#[macro_use]
-extern crate log;
-
-mod error;
 mod future;
+mod listener;
 mod pool;
 mod ready;
+mod rotator;

-pub use self::pool::{Transaction, Pool};
+pub mod base_pool;
+pub mod error;
+pub mod watcher;
+
+pub use self::error::IntoPoolError;
+pub use self::base_pool::{Transaction, Status};
+pub use self::pool::{Pool, Options, ChainApi, EventStream, ExtrinsicFor, BlockHash, ExHash, NumberFor, TransactionFor};
@@ -1,3 +1,4 @@
+
 // Copyright 2018 Parity Technologies (UK) Ltd.
 // This file is part of Substrate.

@@ -15,53 +16,27 @@
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

 use std::{
-	sync::Arc,
-	fmt,
 	collections::HashMap,
+	hash,
 };
-use txpool;
 use watcher;
-
-/// Returns the hash of the latest block.
-pub trait LatestHash {
-	type Hash: Clone;
-
-	/// Hash of the latest block.
-	fn latest_hash(&self) -> Self::Hash;
-}
+use sr_primitives::traits;

 /// Extrinsic pool default listener.
-pub struct Listener<H: ::std::hash::Hash + Eq, C: LatestHash> {
-	watchers: HashMap<H, watcher::Sender<H, C::Hash>>,
-	chain: C,
+pub struct Listener<H: hash::Hash + Eq, H2> {
+	watchers: HashMap<H, watcher::Sender<H, H2>>
 }

-impl<H, C> Listener<H, C> where
-	H: ::std::hash::Hash + Eq + Copy + fmt::Debug + fmt::LowerHex + Default,
-	C: LatestHash,
-{
-	/// Creates a new listener with given latest hash provider.
-	pub fn new(chain: C) -> Self {
+impl<H: hash::Hash + Eq, H2> Default for Listener<H, H2> {
+	fn default() -> Self {
 		Listener {
 			watchers: Default::default(),
-			chain,
 		}
 	}
+}

-	/// Creates a new watcher for given verified extrinsic.
-	///
-	/// The watcher can be used to subscribe to lifecycle events of that extrinsic.
-	pub fn create_watcher<T: txpool::VerifiedTransaction<Hash=H>>(&mut self, xt: Arc<T>) -> watcher::Watcher<H, C::Hash> {
-		let sender = self.watchers.entry(*xt.hash()).or_insert_with(watcher::Sender::default);
-		sender.new_watcher()
-	}
-
-	/// Notify the listeners about extrinsic broadcast.
-	pub fn broadcasted(&mut self, hash: &H, peers: Vec<String>) {
-		self.fire(hash, |watcher| watcher.broadcast(peers));
-	}
-
-	fn fire<F>(&mut self, hash: &H, fun: F) where F: FnOnce(&mut watcher::Sender<H, C::Hash>) {
+impl<H: hash::Hash + traits::Member, H2: Clone> Listener<H, H2> {
+	fn fire<F>(&mut self, hash: &H, fun: F) where F: FnOnce(&mut watcher::Sender<H, H2>) {
 		let clean = if let Some(h) = self.watchers.get_mut(hash) {
 			fun(h);
 			h.is_done()
@@ -73,41 +48,51 @@ impl<H, C> Listener<H, C> where
 			self.watchers.remove(hash);
 		}
 	}
-}

-impl<H, T, C> txpool::Listener<T> for Listener<H, C> where
-	H: ::std::hash::Hash + Eq + Copy + fmt::Debug + fmt::LowerHex + Default,
-	T: txpool::VerifiedTransaction<Hash=H>,
-	C: LatestHash,
-{
-	fn added(&mut self, tx: &Arc<T>, old: Option<&Arc<T>>) {
+	/// Creates a new watcher for given verified extrinsic.
+	///
+	/// The watcher can be used to subscribe to lifecycle events of that extrinsic.
+	pub fn create_watcher(&mut self, hash: H) -> watcher::Watcher<H, H2> {
+		let sender = self.watchers.entry(hash).or_insert_with(watcher::Sender::default);
+		sender.new_watcher()
+	}
+
+	/// Notify the listeners about extrinsic broadcast.
+	pub fn broadcasted(&mut self, hash: &H, peers: Vec<String>) {
+		self.fire(hash, |watcher| watcher.broadcast(peers));
+	}
+
+	/// New transaction was added to the ready pool or promoted from the future pool.
+	pub fn ready(&mut self, tx: &H, old: Option<&H>) {
 		if let Some(old) = old {
-			let hash = tx.hash();
-			self.fire(old.hash(), |watcher| watcher.usurped(*hash));
+			self.fire(old, |watcher| watcher.usurped(tx.clone()));
 		}
 	}

-	fn dropped(&mut self, tx: &Arc<T>, by: Option<&T>) {
-		self.fire(tx.hash(), |watcher| match by {
-			Some(t) => watcher.usurped(*t.hash()),
+	/// New transaction was added to the future pool.
+	pub fn future(&mut self, _tx: &H) {
+	}
+
+	/// Transaction was dropped from the pool because of the limit.
+	pub fn dropped(&mut self, tx: &H, by: Option<&H>) {
+		self.fire(tx, |watcher| match by {
+			Some(t) => watcher.usurped(t.clone()),
 			None => watcher.dropped(),
 		})
 	}

-	fn rejected(&mut self, tx: &Arc<T>, reason: &txpool::ErrorKind) {
-		warn!(target: "transaction-pool", "Extrinsic rejected ({}): {:?}", reason, tx);
+	/// Transaction was rejected from the pool.
+	pub fn rejected(&mut self, tx: &H, is_invalid: bool) {
+		warn!(target: "transaction-pool", "Extrinsic rejected ({}): {:?}", is_invalid, tx);
 	}

-	fn invalid(&mut self, tx: &Arc<T>) {
+	/// Transaction was removed as invalid.
+	pub fn invalid(&mut self, tx: &H) {
 		warn!(target: "transaction-pool", "Extrinsic invalid: {:?}", tx);
 	}

-	fn canceled(&mut self, tx: &Arc<T>) {
-		debug!(target: "transaction-pool", "Extrinsic canceled: {:?}", tx);
-	}
-
-	fn culled(&mut self, tx: &Arc<T>) {
-		let header_hash = self.chain.latest_hash();
-		self.fire(tx.hash(), |watcher| watcher.finalised(header_hash))
+	/// Transaction was pruned from the pool.
+	pub fn pruned(&mut self, header_hash: H2, tx: &H) {
+		self.fire(tx, |watcher| watcher.finalised(header_hash))
 	}
 }
@@ -0,0 +1,333 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate 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.
+
+// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::{
+	collections::HashMap,
+	hash,
+	sync::Arc,
+	time,
+};
+
+use base_pool as base;
+use error;
+use listener::Listener;
+use rotator::PoolRotator;
+use watcher::Watcher;
+
+use futures::sync::mpsc;
+use parking_lot::{Mutex, RwLock};
+use sr_primitives::{
+	generic::BlockId,
+	traits::{self, As},
+	transaction_validity::{TransactionValidity, TransactionTag as Tag},
+};
+
+/// Modification notification event stream type;
+pub type EventStream = mpsc::UnboundedReceiver<()>;
+
+/// Extrinsic hash type for a pool.
+pub type ExHash<A> = <A as ChainApi>::Hash;
+/// Block hash type for a pool.
+pub type BlockHash<A> = <<A as ChainApi>::Block as traits::Block>::Hash;
+/// Extrinsic type for a pool.
+pub type ExtrinsicFor<A> = <<A as ChainApi>::Block as traits::Block>::Extrinsic;
+/// Block number type for the ChainApi
+pub type NumberFor<A> = traits::NumberFor<<A as ChainApi>::Block>;
+/// A type of transaction stored in the pool
+pub type TransactionFor<A> = Arc<base::Transaction<ExHash<A>, TxData<ExtrinsicFor<A>>>>;
+
+/// Concrete extrinsic validation and query logic.
+pub trait ChainApi: Send + Sync {
+	/// Block type.
+	type Block: traits::Block;
+	/// Hash type
+	type Hash: hash::Hash + Eq + traits::Member;
+	/// Error type.
+	type Error: From<error::Error> + error::IntoPoolError;
+
+	/// Verify extrinsic at given block.
+	fn validate_transaction(&self, at: &BlockId<Self::Block>, uxt: &ExtrinsicFor<Self>) -> Result<TransactionValidity, Self::Error>;
+
+	/// Returns a block number given the block id.
+	fn block_id_to_number(&self, at: &BlockId<Self::Block>) -> Result<Option<NumberFor<Self>>, Self::Error>;
+
+	/// Returns a block hash given the block id.
+	fn block_id_to_hash(&self, at: &BlockId<Self::Block>) -> Result<Option<BlockHash<Self>>, Self::Error>;
+
+	/// Hash the extrinsic.
+	fn hash(&self, uxt: &ExtrinsicFor<Self>) -> Self::Hash;
+}
+
+/// Maximum time the transaction will be kept in the pool.
+///
+/// Transactions that don't get included within the limit are removed from the pool.
+const POOL_TIME: time::Duration = time::Duration::from_secs(60 * 5);
+
+/// Additional transaction data
+#[derive(Debug, Serialize, Deserialize)]
+pub struct TxData<Ex> {
+	/// Raw data stored by the user.
+	pub raw: Ex,
+	/// Transaction validity deadline.
+	/// TODO [ToDr] Should we use longevity instead?
+	#[serde(skip)]
+	pub valid_till: Option<time::Instant>,
+}
+
+/// Pool configuration options.
+#[derive(Debug, Clone, Default)]
+pub struct Options;
+
+/// Extrinsics pool.
+pub struct Pool<B: ChainApi> {
+	api: B,
+	listener: RwLock<Listener<ExHash<B>, BlockHash<B>>>,
+	pool: RwLock<base::BasePool<
+		ExHash<B>,
+		TxData<ExtrinsicFor<B>>,
+	>>,
+	import_notification_sinks: Mutex<Vec<mpsc::UnboundedSender<()>>>,
+	rotator: PoolRotator<ExHash<B>>,
+}
+
+impl<B: ChainApi> Pool<B> {
+
+	/// Imports a bunch of unverified extrinsics to the pool
+	pub fn submit_at<T>(&self, at: &BlockId<B::Block>, xts: T) -> Result<Vec<Result<ExHash<B>, B::Error>>, B::Error> where
+		T: IntoIterator<Item=ExtrinsicFor<B>>
+	{
+		let block_number = self.api.block_id_to_number(at)?
+			.ok_or_else(|| error::ErrorKind::Msg(format!("Invalid block id: {:?}", at)).into())?;
+
+		Ok(xts
+			.into_iter()
+			.map(|xt| -> Result<_, B::Error> {
+				let hash = self.api.hash(&xt);
+				if self.rotator.is_banned(&hash) {
+					return Err(error::ErrorKind::TemporarilyBanned.into())?;
+				}
+
+				match self.api.validate_transaction(at, &xt)? {
+					TransactionValidity::Valid(priority, requires, provides, longevity)=> {
+						Ok(base::Transaction {
+							data: TxData {
+								raw: xt,
+								valid_till: Some(time::Instant::now() + POOL_TIME),
+							},
+							hash,
+							priority,
+							requires,
+							provides,
+							longevity,
+						})
+					},
+					TransactionValidity::Invalid => {
+						bail!(error::Error::from(error::ErrorKind::InvalidTransaction))
+					},
+					TransactionValidity::Unknown => {
+						self.listener.write().rejected(&hash, false);
+						bail!(error::Error::from(error::ErrorKind::UnknownTransactionValidity))
+					},
+				}
+			})
+			.map(|tx| {
+				let imported = self.pool.write().import(block_number.as_(), tx?)?;
+
+				self.import_notification_sinks.lock().retain(|sink| sink.unbounded_send(()).is_ok());
+
+				let mut listener = self.listener.write();
+				fire_events(&mut *listener, &imported);
+				Ok(imported.hash().clone())
+			})
+			.collect())
+	}
+
+	/// Imports one unverified extrinsic to the pool
+	pub fn submit_one(&self, at: &BlockId<B::Block>, xt: ExtrinsicFor<B>) -> Result<ExHash<B>, B::Error> {
+		Ok(self.submit_at(at, ::std::iter::once(xt))?.pop().expect("One extrinsic passed; one result returned; qed")?)
+	}
+
+	/// Import a single extrinsic and starts to watch their progress in the pool.
+	pub fn submit_and_watch(&self, at: &BlockId<B::Block>, xt: ExtrinsicFor<B>) -> Result<Watcher<ExHash<B>, BlockHash<B>>, B::Error> {
+		let xt = self.submit_one(at, xt)?;
+		Ok(self.listener.write().create_watcher(xt))
+	}
+
+	/// Prunes ready transactions that provide given list of tags.
+	pub fn prune_tags(&self, at: &BlockId<B::Block>, tags: impl IntoIterator<Item=Tag>) -> Result<(), B::Error> {
+		let block_number = self.api.block_id_to_number(at)?
+			.ok_or_else(|| error::ErrorKind::Msg(format!("Invalid block id: {:?}", at)).into())?;
+
+		let status = self.pool.write().prune_tags(block_number.as_(), tags);
+		{
+			let mut listener = self.listener.write();
+			for promoted in &status.promoted {
+				fire_events(&mut *listener, promoted);
+			}
+			for f in &status.failed {
+				listener.dropped(f, None);
+			}
+		}
+		// try to re-submit pruned transactions since some of them might be still valid.
+		let hashes = status.pruned.iter().map(|tx| tx.hash.clone()).collect::<Vec<_>>();
+		let results = self.submit_at(at, status.pruned.into_iter().map(|tx| tx.data.raw.clone()))?;
+		// Fire mined event for transactions that became invalid.
+		let hashes = results.into_iter().enumerate().filter_map(|(idx, r)| match r.map_err(error::IntoPoolError::into_pool_error) {
+			Err(Ok(err)) => match err.kind() {
+				error::ErrorKind::InvalidTransaction => Some(hashes[idx].clone()),
+				_ => None,
+			},
+			_ => None,
+		});
+		{
+			let header_hash = self.api.block_id_to_hash(at)?
+				.ok_or_else(|| error::ErrorKind::Msg(format!("Invalid block id: {:?}", at)).into())?;
+			let mut listener = self.listener.write();
+			for h in hashes {
+				listener.pruned(header_hash, &h)
+			}
+		}
+		// clear old transactions
+		self.clear_stale(at)?;
+		Ok(())
+	}
+
+	/// Removes stale transactions from the pool.
+	///
+	/// Stale transactions are transaction beyond their longevity period.
+	/// Note this function does not remove transactions that are already included in the chain.
+	/// See `prune_tags` ifyou want this.
+	pub fn clear_stale(&self, _at: &BlockId<B::Block>) -> Result<(), B::Error> {
+		let now = time::Instant::now();
+		let to_remove = self.ready(|pending| pending
+			.filter(|tx| self.rotator.ban_if_stale(&now, &tx))
+			.map(|tx| tx.hash.clone())
+			.collect::<Vec<_>>()
+		);
+		// removing old transactions
+		self.remove_invalid(&to_remove);
+		// clear banned transactions timeouts
+		self.rotator.clear_timeouts(&now);
+
+		Ok(())
+	}
+}
+
+impl<B: ChainApi> Pool<B> {
+	/// Create a new transaction pool.
+	/// TODO [ToDr] Options
+	pub fn new(_options: Options, api: B) -> Self {
+		Pool {
+			api,
+			listener: Default::default(),
+			pool: Default::default(),
+			import_notification_sinks: Default::default(),
+			rotator: Default::default(),
+		}
+	}
+
+	/// Return an event stream of transactions imported to the pool.
+	pub fn import_notification_stream(&self) -> EventStream {
+		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<ExHash<B>, Vec<String>>) {
+		let mut listener = self.listener.write();
+		for (hash, peers) in propagated.into_iter() {
+			listener.broadcasted(&hash, peers);
+		}
+	}
+
+	/// Remove from the pool.
+	pub fn remove_invalid(&self, hashes: &[ExHash<B>]) -> Vec<TransactionFor<B>> {
+		// temporarily ban invalid transactions
+		debug!(target: "txpool", "Banning invalid transactions: {:?}", hashes);
+		self.rotator.ban(&time::Instant::now(), hashes);
+
+		let invalid = self.pool.write().remove_invalid(hashes);
+
+		let mut listener = self.listener.write();
+		for tx in &invalid {
+			listener.invalid(&tx.hash);
+		}
+
+		invalid
+	}
+
+	/// Get ready transactions ordered by priority
+	pub fn ready<F, X>(&self, f: F) -> X where
+		F: FnOnce(&mut Iterator<Item=TransactionFor<B>>) -> X,
+	{
+		let pool = self.pool.read();
+		let mut ready = pool.ready();
+		f(&mut ready)
+	}
+
+	/// Returns all transactions in the pool.
+	///
+	/// Be careful with large limit values, as querying the entire pool might be time consuming.
+	pub fn all(&self, limit: usize) -> Vec<ExtrinsicFor<B>> {
+		self.ready(|it| it.take(limit).map(|ex| ex.data.raw.clone()).collect())
+	}
+
+	/// Returns pool status.
+	pub fn status(&self) -> base::Status {
+		self.pool.read().status()
+	}
+
+	/// Returns transaction hash
+	pub fn hash_of(&self, xt: &ExtrinsicFor<B>) -> ExHash<B> {
+		self.api.hash(xt)
+	}
+}
+
+fn fire_events<H, H2, Ex>(
+	listener: &mut Listener<H, H2>,
+	imported: &base::Imported<H, Ex>,
+) where
+	H: hash::Hash + Eq + traits::Member,
+	H2: Clone,
+{
+	match *imported {
+		base::Imported::Ready { ref promoted, ref failed, ref removed, ref hash } => {
+			listener.ready(hash, None);
+			for f in failed {
+				listener.rejected(f, true);
+			}
+			for r in removed {
+				listener.dropped(&r.hash, Some(hash));
+			}
+			for p in promoted {
+				listener.ready(p, None);
+			}
+		},
+		base::Imported::Future { ref hash } => {
+			listener.future(hash)
+		},
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	#[test]
+	#[ignore]
+	fn should_have_some_basic_tests() {
+		assert_eq!(true, false);
+	}
+}
@@ -28,16 +28,26 @@ use sr_primitives::transaction_validity::{

 use error;
 use future::WaitingTransaction;
-use pool::{BlockNumber, Transaction};
+use base_pool::{BlockNumber, Transaction};

-#[derive(Debug, Clone)]
-pub struct TransactionRef<Hash> {
-	pub transaction: Arc<Transaction<Hash>>,
+#[derive(Debug)]
+pub struct TransactionRef<Hash, Ex> {
+	pub transaction: Arc<Transaction<Hash, Ex>>,
 	pub valid_till: BlockNumber,
 	pub insertion_id: u64,
 }

-impl<Hash> Ord for TransactionRef<Hash> {
+impl<Hash, Ex> Clone for TransactionRef<Hash, Ex> {
+	fn clone(&self) -> Self {
+		TransactionRef {
+			transaction: self.transaction.clone(),
+			valid_till: self.valid_till,
+			insertion_id: self.insertion_id,
+		}
+	}
+}
+
+impl<Hash, Ex> Ord for TransactionRef<Hash, Ex> {
 	fn cmp(&self, other: &Self) -> cmp::Ordering {
 		self.transaction.priority.cmp(&other.transaction.priority)
 			.then(other.valid_till.cmp(&self.valid_till))
@@ -45,23 +55,23 @@ impl<Hash> Ord for TransactionRef<Hash> {
 	}
 }

-impl<Hash> PartialOrd for TransactionRef<Hash> {
+impl<Hash, Ex> PartialOrd for TransactionRef<Hash, Ex> {
 	fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
 		Some(self.cmp(other))
 	}
 }

-impl<Hash> PartialEq for TransactionRef<Hash> {
+impl<Hash, Ex> PartialEq for TransactionRef<Hash, Ex> {
 	fn eq(&self, other: &Self) -> bool {
 		self.cmp(other) == cmp::Ordering::Equal
 	}
 }
-impl<Hash> Eq for TransactionRef<Hash> {}
+impl<Hash, Ex> Eq for TransactionRef<Hash, Ex> {}

 #[derive(Debug)]
-struct ReadyTx<Hash> {
+struct ReadyTx<Hash, Ex> {
 	/// A reference to a transaction
-	pub transaction: TransactionRef<Hash>,
+	pub transaction: TransactionRef<Hash, Ex>,
 	/// A list of transactions that get unlocked by this one
 	pub unlocks: Vec<Hash>,
 	/// How many required tags are provided inherently
@@ -79,19 +89,19 @@ qed
 "#;

 #[derive(Debug)]
-pub struct ReadyTransactions<Hash: hash::Hash + Eq> {
+pub struct ReadyTransactions<Hash: hash::Hash + Eq, Ex> {
 	/// Insertion id
 	insertion_id: u64,
 	/// tags that are provided by Ready transactions
 	provided_tags: HashMap<Tag, Hash>,
 	/// Transactions that are ready (i.e. don't have any requirements external to the pool)
-	ready: HashMap<Hash, ReadyTx<Hash>>,
+	ready: HashMap<Hash, ReadyTx<Hash, Ex>>,
 	// ^^ TODO [ToDr] Consider wrapping this into `Arc<RwLock<>>` and allow multiple concurrent iterators
 	/// Best transactions that are ready to be included to the block without any other previous transaction.
-	best: BTreeSet<TransactionRef<Hash>>,
+	best: BTreeSet<TransactionRef<Hash, Ex>>,
 }

-impl<Hash: hash::Hash + Eq> Default for ReadyTransactions<Hash> {
+impl<Hash: hash::Hash + Eq, Ex> Default for ReadyTransactions<Hash, Ex> {
 	fn default() -> Self {
 		ReadyTransactions {
 			insertion_id: Default::default(),
@@ -102,7 +112,7 @@ impl<Hash: hash::Hash + Eq> Default for ReadyTransactions<Hash> {
 	}
 }

-impl<Hash: hash::Hash + Member> ReadyTransactions<Hash> {
+impl<Hash: hash::Hash + Member, Ex> ReadyTransactions<Hash, Ex> {
 	/// Borrows a map of tags that are provided by transactions in this queue.
 	pub fn provided_tags(&self) -> &HashMap<Tag, Hash> {
 		&self.provided_tags
@@ -119,7 +129,7 @@ impl<Hash: hash::Hash + Member> ReadyTransactions<Hash> {
 	/// - transactions that are valid for a shorter time go first
 	/// 4. Lastly we sort by the time in the queue
 	/// - transactions that are longer in the queue go first
-	pub fn get<'a>(&'a self) -> impl Iterator<Item=Arc<Transaction<Hash>>> + 'a {
+	pub fn get<'a>(&'a self) -> impl Iterator<Item=Arc<Transaction<Hash, Ex>>> + 'a {
 		BestIterator {
 			all: &self.ready,
 			best: self.best.clone(),
@@ -134,8 +144,8 @@ impl<Hash: hash::Hash + Member> ReadyTransactions<Hash> {
 	pub fn import(
 		&mut self,
 		block_number: BlockNumber,
-		tx: WaitingTransaction<Hash>,
-	) -> error::Result<Vec<Arc<Transaction<Hash>>>> {
+		tx: WaitingTransaction<Hash, Ex>,
+	) -> error::Result<Vec<Arc<Transaction<Hash, Ex>>>> {
 		assert!(tx.is_ready(), "Only ready transactions can be imported.");
 		assert!(!self.ready.contains_key(&tx.transaction.hash), "Transaction is already imported.");

@@ -194,7 +204,7 @@ impl<Hash: hash::Hash + Member> ReadyTransactions<Hash> {
 	/// NOTE removing a transaction will also cause a removal of all transactions that depend on that one
 	/// (i.e. the entire subgraph that this transaction is a start of will be removed).
 	/// All removed transactions are returned.
-	pub fn remove_invalid(&mut self, hashes: &[Hash]) -> Vec<Arc<Transaction<Hash>>> {
+	pub fn remove_invalid(&mut self, hashes: &[Hash]) -> Vec<Arc<Transaction<Hash, Ex>>> {
 		let mut removed = vec![];
 		let mut to_remove = hashes.iter().cloned().collect::<Vec<_>>();

@@ -236,7 +246,7 @@ impl<Hash: hash::Hash + Member> ReadyTransactions<Hash> {
 	/// All transactions that lead to a transaction, which provides this tag
 	/// are going to be removed from the queue, but no other transactions are touched -
 	/// i.e. all other subgraphs starting from given tag are still considered valid & ready.
-	pub fn prune_tags(&mut self, tag: Tag) -> Vec<Arc<Transaction<Hash>>> {
+	pub fn prune_tags(&mut self, tag: Tag) -> Vec<Arc<Transaction<Hash, Ex>>> {
 		let mut removed = vec![];
 		let mut to_remove = vec![tag];

@@ -308,7 +318,7 @@ impl<Hash: hash::Hash + Member> ReadyTransactions<Hash> {
 	/// We remove/replace old transactions in case they have lower priority.
 	///
 	/// In case replacement is succesful returns a list of removed transactions.
-	fn replace_previous(&mut self, tx: &Transaction<Hash>) -> error::Result<Vec<Arc<Transaction<Hash>>>> {
+	fn replace_previous(&mut self, tx: &Transaction<Hash, Ex>) -> error::Result<Vec<Arc<Transaction<Hash, Ex>>>> {
 		let mut to_remove = {
 			// check if we are replacing a transaction
 			let replace_hashes = tx.provides
@@ -364,23 +374,22 @@ impl<Hash: hash::Hash + Member> ReadyTransactions<Hash> {
 	}

 	/// Returns number of transactions in this queue.
-	#[cfg(test)]
 	pub fn len(&self) -> usize {
 		self.ready.len()
 	}

 }

-pub struct BestIterator<'a, Hash: 'a> {
-	all: &'a HashMap<Hash, ReadyTx<Hash>>,
-	awaiting: HashMap<Hash, (usize, TransactionRef<Hash>)>,
-	best: BTreeSet<TransactionRef<Hash>>,
+pub struct BestIterator<'a, Hash: 'a, Ex: 'a> {
+	all: &'a HashMap<Hash, ReadyTx<Hash, Ex>>,
+	awaiting: HashMap<Hash, (usize, TransactionRef<Hash, Ex>)>,
+	best: BTreeSet<TransactionRef<Hash, Ex>>,
 }

-impl<'a, Hash: 'a + hash::Hash + Member> BestIterator<'a, Hash> {
+impl<'a, Hash: 'a + hash::Hash + Member, Ex: 'a> BestIterator<'a, Hash, Ex> {
 	/// Depending on number of satisfied requirements insert given ref
 	/// either to awaiting set or to best set.
-	fn best_or_awaiting(&mut self, satisfied: usize, tx_ref: TransactionRef<Hash>) {
+	fn best_or_awaiting(&mut self, satisfied: usize, tx_ref: TransactionRef<Hash, Ex>) {
 		if satisfied == tx_ref.transaction.requires.len() {
 			// If we have satisfied all deps insert to best
 			self.best.insert(tx_ref);
@@ -392,8 +401,8 @@ impl<'a, Hash: 'a + hash::Hash + Member> BestIterator<'a, Hash> {
 	}
 }

-impl<'a, Hash: 'a + hash::Hash + Member> Iterator for BestIterator<'a, Hash> {
-	type Item = Arc<Transaction<Hash>>;
+impl<'a, Hash: 'a + hash::Hash + Member, Ex: 'a> Iterator for BestIterator<'a, Hash, Ex> {
+	type Item = Arc<Transaction<Hash, Ex>>;

 	fn next(&mut self) -> Option<Self::Item> {
 		let best = self.best.iter().next_back()?.clone();
@@ -432,9 +441,9 @@ fn remove_item<T: PartialEq>(vec: &mut Vec<T>, item: &T) {
 mod tests {
 	use super::*;

-	fn tx(id: u8) -> Transaction<u64> {
+	fn tx(id: u8) -> Transaction<u64, Vec<u8>> {
 		Transaction {
-			ex: vec![id],
+			data: vec![id],
 			hash: id as u64,
 			priority: 1,
 			longevity: 2,
@@ -494,7 +503,7 @@ mod tests {
 		tx4.provides = vec![];
 		let block_number = 1;
 		let tx5 = Transaction {
-			ex: vec![5],
+			data: vec![5],
 			hash: 5,
 			priority: 1,
 			longevity: u64::max_value(),	// use the max_value() here for testing.
@@ -517,7 +526,7 @@ mod tests {
 		// then
 		assert_eq!(ready.best.len(), 1);

-		let mut it = ready.get().map(|tx| tx.ex[0]);
+		let mut it = ready.get().map(|tx| tx.data[0]);

 		assert_eq!(it.next(), Some(1));
 		assert_eq!(it.next(), Some(2));
@@ -21,13 +21,13 @@

 use std::{
 	collections::HashMap,
-	fmt,
 	hash,
 	time::{Duration, Instant},
 };
 use parking_lot::RwLock;
-use txpool::VerifiedTransaction;
-use Verified;
+
+use base_pool::Transaction;
+use pool::TxData;

 /// Expected size of the banned extrinsics cache.
 const EXPECTED_SIZE: usize = 2048;
@@ -75,18 +75,19 @@ impl<Hash: hash::Hash + Eq + Clone> PoolRotator<Hash> {
 		}
 	}

+
 	/// Bans extrinsic if it's stale.
 	///
 	/// Returns `true` if extrinsic is stale and got banned.
-	pub fn ban_if_stale<Ex, VEx>(&self, now: &Instant, xt: &Verified<Ex, VEx>) -> bool where
-		VEx: VerifiedTransaction<Hash=Hash>,
-		Hash: fmt::Debug + fmt::LowerHex,
-	{
-		if &xt.valid_till > now {
-			return false;
+	pub fn ban_if_stale<Ex>(&self, now: &Instant, xt: &Transaction<Hash, TxData<Ex>>) -> bool {
+		match xt.data.valid_till {
+			Some(ref valid_till) if valid_till > now => {
+				return false;
+			}
+			_ => {},
 		}

-		self.ban(now, &[xt.verified.hash().clone()]);
+		self.ban(now, &[xt.hash.clone()]);
 		true
 	}

@@ -101,8 +102,9 @@ impl<Hash: hash::Hash + Eq + Clone> PoolRotator<Hash> {
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use pool::tests::VerifiedTransaction;
-	use test_client::runtime::Hash;
+
+	type Hash = u64;
+	type Ex = ();

 	fn rotator() -> PoolRotator<Hash> {
 		PoolRotator {
@@ -111,16 +113,18 @@ mod tests {
 		}
 	}

-	fn tx() -> (Hash, Verified<u64, VerifiedTransaction>) {
-		let hash = 5.into();
-		let tx = Verified {
-			original: 5,
-			verified: VerifiedTransaction {
-				hash,
-				sender: Default::default(),
-				nonce: Default::default(),
+	fn tx() -> (Hash, Transaction<Hash, TxData<Ex>>) {
+		let hash = 5u64;
+		let tx = Transaction {
+			data: TxData {
+				raw: (),
+				valid_till: Some(Instant::now()),
 			},
-			valid_till: Instant::now(),
+			hash: hash.clone(),
+			priority: 5,
+			longevity: 3,
+			requires: vec![],
+			provides: vec![],
 		};

 		(hash, tx)
@@ -175,16 +179,18 @@ mod tests {
 	#[test]
 	fn should_garbage_collect() {
 		// given
-		fn tx_with(i: u64, time: Instant) -> Verified<u64, VerifiedTransaction> {
-			let hash = i.into();
-			Verified {
-				original: i,
-				verified: VerifiedTransaction {
-					hash,
-					sender: Default::default(),
-					nonce: Default::default(),
+		fn tx_with(i: u64, time: Instant) -> Transaction<Hash, TxData<Ex>> {
+			let hash = i;
+			Transaction {
+				data: TxData {
+					raw: (),
+					valid_till: Some(time),
 				},
-				valid_till: time,
+				hash,
+				priority: 5,
+				longevity: 3,
+				requires: vec![],
+				provides: vec![],
 			}
 		}

@@ -25,6 +25,10 @@ use futures::{
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub enum Status<H, H2> {
+	/// Extrinsic is part of the future queue.
+	Future,
+	/// Extrinsic is part of the ready queue.
+	Ready,
 	/// Extrinsic has been finalised in block with given hash.
 	Finalised(H2),
 	/// Some state change (perhaps another extrinsic was included) rendered this extrinsic invalid.
@@ -64,7 +68,7 @@ impl<H, H2> Default for Sender<H, H2> {
 	fn default() -> Self {
 		Sender {
 			receivers: Default::default(),
-			finalised: Default::default(),
+			finalised: false,
 		}
 	}
 }
@@ -0,0 +1,78 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate 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.
+
+// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Chain api required for the transaction pool.
+
+use std::{
+	sync::Arc,
+};
+use client::{self, runtime_api::TaggedTransactionQueue};
+use parity_codec::Encode;
+use txpool;
+use substrate_primitives::{
+	H256,
+	Blake2Hasher,
+	Hasher,
+};
+use sr_primitives::{
+	generic::BlockId,
+	traits,
+	transaction_validity::TransactionValidity,
+};
+
+use error;
+
+/// The transaction pool logic
+pub struct ChainApi<B, E, Block: traits::Block> {
+	client: Arc<client::Client<B, E, Block>>,
+}
+
+impl<B, E, Block: traits::Block> ChainApi<B, E, Block> {
+	/// Create new transaction pool logic.
+	pub fn new(client: Arc<client::Client<B, E, Block>>) -> Self {
+		ChainApi {
+			client,
+		}
+	}
+}
+
+impl<B, E, Block> txpool::ChainApi for ChainApi<B, E, Block> where
+	Block: traits::Block,
+	B: client::backend::Backend<Block, Blake2Hasher> + Send + Sync + 'static,
+	E: client::CallExecutor<Block, Blake2Hasher> + Send + Sync + Clone + 'static,
+{
+	type Block = Block;
+	type Hash = H256;
+	type Error = error::Error;
+
+	fn validate_transaction(&self, at: &BlockId<Self::Block>, uxt: &txpool::ExtrinsicFor<Self>) -> error::Result<TransactionValidity> {
+		Ok(self.client.validate_transaction(at, uxt)?)
+	}
+
+	// TODO [toDr] Use proper lbock number type
+	fn block_id_to_number(&self, at: &BlockId<Self::Block>) -> error::Result<Option<txpool::NumberFor<Self>>> {
+		Ok(self.client.block_number_from_id(at)?)
+	}
+
+	fn block_id_to_hash(&self, at: &BlockId<Self::Block>) -> error::Result<Option<txpool::BlockHash<Self>>> {
+		Ok(self.client.block_hash_from_id(at)?)
+	}
+
+	fn hash(&self, ex: &txpool::ExtrinsicFor<Self>) -> Self::Hash {
+		Blake2Hasher::hash(&ex.encode())
+	}
+}
+
@@ -14,20 +14,23 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

-//! External Error trait for extrinsic pool.
+//! Transaction pool error.

+use client;
 use txpool;

-/// Extrinsic pool error.
-pub trait IntoPoolError: ::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) }
+error_chain! {
+	links {
+		Client(client::error::Error, client::error::ErrorKind) #[doc = "Client error"];
+		Pool(txpool::error::Error, txpool::error::ErrorKind) #[doc = "Pool error"];
+	}
 }

-impl IntoPoolError for txpool::Error {
-	fn into_pool_error(self) -> Result<txpool::Error, Self> { Ok(self) }
+impl txpool::IntoPoolError for Error {
+	fn into_pool_error(self) -> ::std::result::Result<txpool::error::Error, Self> {
+		match self {
+			Error(ErrorKind::Pool(e), c) => Ok(txpool::error::Error(e, c)),
+			e => Err(e),
+		}
+	}
 }
@@ -15,35 +15,31 @@
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

 // tag::description[]
-//! Generic extrinsic pool.
+//! Substrate transaction pool.
 // end::description[]

 #![warn(missing_docs)]
 #![warn(unused_extern_crates)]

-extern crate futures;
-extern crate parking_lot;
-extern crate sr_primitives as runtime_primitives;
+extern crate parity_codec;
+extern crate sr_primitives;
+extern crate substrate_client as client;
+extern crate substrate_primitives;
+
+pub extern crate substrate_transaction_graph as txpool;

 #[macro_use]
-extern crate log;
-extern crate serde;
-#[macro_use]
-extern crate serde_derive;
-extern crate transaction_pool as txpool;
-#[cfg(test)] extern crate substrate_test_client as test_client;
-#[cfg(test)] extern crate substrate_keyring as keyring;
-#[cfg(test)] extern crate parity_codec as codec;
+extern crate error_chain;

-pub mod watcher;
-mod error;
-mod listener;
-mod pool;
-mod rotator;
+#[cfg(test)]
+extern crate substrate_test_client as test_client;
+#[cfg(test)]
+extern crate substrate_keyring as keyring;

-pub use listener::Listener;
-pub use pool::{Pool, ChainApi, EventStream, Verified, VerifiedFor, ExtrinsicFor, ExHash, AllExtrinsics, HashOf};
-pub use txpool::scoring;
-pub use txpool::{Error, ErrorKind};
-pub use error::IntoPoolError;
-pub use txpool::{Options, Status, LightStatus, VerifiedTransaction, Readiness, Transaction};
+mod api;
+#[cfg(test)]
+mod tests;
+
+pub mod error;
+
+pub use api::ChainApi;
@@ -1,626 +0,0 @@
-// Copyright 2018 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate 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.
-
-// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-use std::{
-	collections::{BTreeMap, HashMap},
-	fmt,
-	sync::Arc,
-	time,
-};
-use futures::sync::mpsc;
-use parking_lot::{Mutex, RwLock};
-use serde::{Serialize, de::DeserializeOwned};
-use txpool::{self, Scoring, Readiness};
-
-use error::IntoPoolError;
-use listener::{self, Listener};
-use rotator::PoolRotator;
-use watcher::Watcher;
-
-use runtime_primitives::{generic::BlockId, traits};
-
-/// Modification notification event stream type;
-pub type EventStream = mpsc::UnboundedReceiver<()>;
-
-/// Extrinsic hash type for a pool.
-pub type ExHash<A> = <A as ChainApi>::Hash;
-/// Extrinsic type for a pool.
-pub type ExtrinsicFor<A> = <<A as ChainApi>::Block as traits::Block>::Extrinsic;
-/// Verified extrinsic data for `ChainApi`.
-pub type VerifiedFor<A> = Verified<ExtrinsicFor<A>, <A as ChainApi>::VEx>;
-/// A collection of all extrinsics.
-pub type AllExtrinsics<A> = BTreeMap<<<A as ChainApi>::VEx as txpool::VerifiedTransaction>::Sender, Vec<ExtrinsicFor<A>>>;
-
-/// Verified extrinsic struct. Wraps original extrinsic and verification info.
-#[derive(Debug)]
-pub struct Verified<Ex, VEx> {
-	/// Original extrinsic.
-	pub original: Ex,
-	/// Verification data.
-	pub verified: VEx,
-	/// Pool deadline, after it's reached we remove the extrinsic from the pool.
-	pub valid_till: time::Instant,
-}
-
-impl<Ex, VEx> txpool::VerifiedTransaction for Verified<Ex, VEx>
-where
-	Ex: fmt::Debug,
-	VEx: txpool::VerifiedTransaction,
-{
-	type Hash = <VEx as txpool::VerifiedTransaction>::Hash;
-	type Sender = <VEx as txpool::VerifiedTransaction>::Sender;
-
-	fn hash(&self) -> &Self::Hash {
-		self.verified.hash()
-	}
-
-	fn sender(&self) -> &Self::Sender {
-		self.verified.sender()
-	}
-
-	fn mem_usage(&self) -> usize {
-		// TODO: add `original` mem usage.
-		self.verified.mem_usage()
-	}
-}
-
-/// Concrete extrinsic validation and query logic.
-pub trait ChainApi: Send + Sync {
-	/// Block type.
-	type Block: traits::Block;
-	/// Extrinsic hash type.
-	type Hash: ::std::hash::Hash + Eq + Copy + fmt::Debug + fmt::LowerHex + Serialize + DeserializeOwned + ::std::str::FromStr + Send + Sync + Default + 'static;
-	/// Extrinsic sender type.
-	type Sender: ::std::hash::Hash + fmt::Debug + Serialize + DeserializeOwned + Eq + Clone + Send + Sync + Ord + Default;
-	/// Unchecked extrinsic type.
-	/// Verified extrinsic type.
-	type VEx: txpool::VerifiedTransaction<Hash=Self::Hash, Sender=Self::Sender> + Send + Sync + Clone;
-	/// Readiness evaluator
-	type Ready;
-	/// Error type.
-	type Error: From<txpool::Error> + IntoPoolError;
-	/// Score type.
-	type Score: ::std::cmp::Ord + Clone + Default + fmt::Debug + Send + Send + Sync + fmt::LowerHex;
-	/// Custom scoring update event type.
-	type Event: ::std::fmt::Debug;
-
-	/// Verify extrinsic at given block.
-	fn verify_transaction(&self, at: &BlockId<Self::Block>, uxt: &ExtrinsicFor<Self>) -> Result<Self::VEx, Self::Error>;
-
-	/// Create new readiness evaluator.
-	fn ready(&self) -> Self::Ready;
-
-	/// Check readiness for verified extrinsic at given block.
-	fn is_ready(&self, at: &BlockId<Self::Block>, context: &mut Self::Ready, xt: &VerifiedFor<Self>) -> Readiness;
-
-	/// Decides on ordering of `T`s from a particular sender.
-	fn compare(old: &VerifiedFor<Self>, other: &VerifiedFor<Self>) -> ::std::cmp::Ordering;
-
-	/// Decides how to deal with two transactions from a sender that seem to occupy the same slot in the queue.
-	fn choose(old: &VerifiedFor<Self>, new: &VerifiedFor<Self>) -> txpool::scoring::Choice;
-
-	/// Updates the transaction scores given a list of transactions and a change to previous scoring.
-	/// NOTE: you can safely assume that both slices have the same length.
-	/// (i.e. score at index `i` represents transaction at the same index)
-	fn update_scores(xts: &[txpool::Transaction<VerifiedFor<Self>>], scores: &mut [Self::Score], change: txpool::scoring::Change<Self::Event>);
-
-	/// Decides if `new` should push out `old` transaction from the pool.
-	///
-	/// NOTE returning `InsertNew` here can lead to some transactions being accepted above pool limits.
-	fn should_replace(old: &VerifiedFor<Self>, new: &VerifiedFor<Self>) -> txpool::scoring::Choice;
-
-	/// Returns hash of the latest block in chain.
-	fn latest_hash(&self) -> HashOf<Self::Block>;
-}
-
-/// Returns block's hash type.
-pub type HashOf<B> = <B as traits::Block>::Hash;
-
-impl<T: ChainApi> listener::LatestHash for Arc<T> {
-	type Hash = HashOf<T::Block>;
-
-	fn latest_hash(&self) -> HashOf<T::Block> {
-		ChainApi::latest_hash(&**self)
-	}
-}
-
-pub struct Ready<'a, 'b, B: 'a + ChainApi> {
-	api: &'a B,
-	at: &'b BlockId<B::Block>,
-	context: B::Ready,
-	rotator: &'a PoolRotator<B::Hash>,
-	now: time::Instant,
-}
-
-impl<'a, 'b, B: ChainApi> txpool::Ready<VerifiedFor<B>> for Ready<'a, 'b, B> {
-	fn is_ready(&mut self, xt: &VerifiedFor<B>) -> Readiness {
-		if self.rotator.ban_if_stale(&self.now, xt) {
-			debug!(target: "transaction-pool", "[{:?}] Banning as stale.", txpool::VerifiedTransaction::hash(xt));
-			return Readiness::Stale;
-		}
-
-		self.api.is_ready(self.at, &mut self.context, xt)
-	}
-}
-
-pub struct ScoringAdapter<T>(::std::marker::PhantomData<T>);
-
-impl<T> ::std::fmt::Debug for ScoringAdapter<T> {
-	fn fmt(&self, _f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
-		Ok(())
-	}
-}
-
-impl<T: ChainApi> Scoring<VerifiedFor<T>> for ScoringAdapter<T> {
-	type Score = <T as ChainApi>::Score;
-	type Event = <T as ChainApi>::Event;
-
-	fn compare(&self, old: &VerifiedFor<T>, other: &VerifiedFor<T>) -> ::std::cmp::Ordering {
-		T::compare(old, other)
-	}
-
-	fn choose(&self, old: &VerifiedFor<T>, new: &VerifiedFor<T>) -> txpool::scoring::Choice {
-		T::choose(old, new)
-	}
-
-	fn update_scores(&self, xts: &[txpool::Transaction<VerifiedFor<T>>], scores: &mut [Self::Score], change: txpool::scoring::Change<Self::Event>) {
-		T::update_scores(xts, scores, change)
-	}
-
-	fn should_replace(&self, old: &VerifiedFor<T>, new: &VerifiedFor<T>) -> txpool::scoring::Choice {
-		T::should_replace(old, new)
-	}
-}
-
-/// Maximum time the transaction will be kept in the pool.
-///
-/// Transactions that don't get included within the limit are removed from the pool.
-const POOL_TIME: time::Duration = time::Duration::from_secs(60 * 5);
-
-/// Extrinsics pool.
-pub struct Pool<B: ChainApi> {
-	api: Arc<B>,
-	pool: RwLock<txpool::Pool<
-		VerifiedFor<B>,
-		ScoringAdapter<B>,
-		Listener<B::Hash, Arc<B>>,
-	>>,
-	import_notification_sinks: Mutex<Vec<mpsc::UnboundedSender<()>>>,
-	rotator: PoolRotator<B::Hash>,
-}
-
-impl<B: ChainApi> Pool<B> {
-	/// Create a new transaction pool.
-	pub fn new(options: txpool::Options, api: B) -> Self {
-		let api = Arc::new(api);
-		Pool {
-			pool: RwLock::new(txpool::Pool::new(Listener::new(api.clone()), ScoringAdapter::<B>(Default::default()), options)),
-			import_notification_sinks: Default::default(),
-			api,
-			rotator: Default::default(),
-		}
-	}
-
-	/// Imports a pre-verified extrinsic to the pool.
-	pub fn import(&self, xt: VerifiedFor<B>) -> Result<Arc<VerifiedFor<B>>, B::Error> {
-		let result = self.pool.write().import(xt)?;
-
-		self.import_notification_sinks.lock()
-			.retain(|sink| sink.unbounded_send(()).is_ok());
-
-		Ok(result)
-	}
-
-	/// Return an event stream of transactions imported to the pool.
-	pub fn import_notification_stream(&self) -> EventStream {
-		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<B::Hash, Vec<String>>) {
-		for (hash, peers) in propagated.into_iter() {
-			self.pool.write().listener_mut().broadcasted(&hash, peers);
-		}
-	}
-
-	/// Imports a bunch of unverified extrinsics to the pool
-	pub fn submit_at<T>(&self, at: &BlockId<B::Block>, xts: T) -> Result<Vec<Arc<VerifiedFor<B>>>, B::Error> where
-		T: IntoIterator<Item=ExtrinsicFor<B>>
-	{
-		xts
-			.into_iter()
-			.map(|xt| {
-				match self.api.verify_transaction(at, &xt) {
-					Ok(ref verified) if self.rotator.is_banned(txpool::VerifiedTransaction::hash(verified)) => {
-						return (Err(txpool::Error::from("Temporarily Banned".to_owned()).into()), xt)
-					},
-					result => (result, xt),
-				}
-			})
-			.map(|(v, xt)| {
-				let xt = Verified {
-					original: xt,
-					verified: v?,
-					valid_till: time::Instant::now() + POOL_TIME,
-				};
-				Ok(self.pool.write().import(xt)?)
-			})
-			.collect()
-	}
-
-	/// Imports one unverified extrinsic to the pool
-	pub fn submit_one(&self, at: &BlockId<B::Block>, xt: ExtrinsicFor<B>) -> Result<Arc<VerifiedFor<B>>, B::Error> {
-		Ok(self.submit_at(at, ::std::iter::once(xt))?.pop().expect("One extrinsic passed; one result returned; qed"))
-	}
-
-	/// Import a single extrinsic and starts to watch their progress in the pool.
-	pub fn submit_and_watch(&self, at: &BlockId<B::Block>, xt: ExtrinsicFor<B>) -> Result<Watcher<B::Hash, HashOf<B::Block>>, B::Error> {
-		let xt = self.submit_at(at, Some(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: &[B::Hash], is_valid: bool) -> Vec<Option<Arc<VerifiedFor<B>>>> {
-		let mut pool = self.pool.write();
-		let mut results = Vec::with_capacity(hashes.len());
-
-		// temporarily ban invalid transactions
-		if !is_valid {
-			debug!(target: "transaction-pool", "Banning invalid transactions: {:?}", hashes);
-			self.rotator.ban(&time::Instant::now(), hashes);
-		}
-
-		for hash in hashes {
-			results.push(pool.remove(hash, is_valid));
-		}
-
-		results
-	}
-
-	/// Cull transactions from the queue.
-	pub fn cull_from(
-		&self,
-		at: &BlockId<B::Block>,
-		senders: Option<&[<B::VEx as txpool::VerifiedTransaction>::Sender]>,
-	) -> usize
-	{
-		self.rotator.clear_timeouts(&time::Instant::now());
-		let ready = self.ready(at);
-		self.pool.write().cull(senders, ready)
-	}
-
-	/// Cull old transactions from the queue.
-	pub fn cull(&self, at: &BlockId<B::Block>) -> Result<usize, B::Error> {
-		Ok(self.cull_from(at, None))
-	}
-
-	/// Cull transactions from the queue and then compute the pending set.
-	pub fn cull_and_get_pending<F, T>(&self, at: &BlockId<B::Block>, f: F) -> Result<T, B::Error> where
-		F: FnOnce(txpool::PendingIterator<VerifiedFor<B>, Ready<B>, ScoringAdapter<B>, Listener<B::Hash, Arc<B>>>) -> T,
-	{
-		self.cull_from(at, None);
-		Ok(self.pending(at, f))
-	}
-
-	/// Get the full status of the queue (including readiness)
-	pub fn status<R: txpool::Ready<VerifiedFor<B>>>(&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()
-	}
-
-	/// Removes all transactions from given sender
-	pub fn remove_sender(&self, sender: <B::VEx as txpool::VerifiedTransaction>::Sender) -> Vec<Arc<VerifiedFor<B>>> {
-		let mut pool = self.pool.write();
-		let pending = pool.pending_from_sender(|_: &VerifiedFor<B>| txpool::Readiness::Ready, &sender).collect();
-		// remove all transactions from this sender
-		pool.cull(Some(&[sender]), |_: &VerifiedFor<B>| txpool::Readiness::Stale);
-		pending
-	}
-
-	/// Retrieve the pending set. Be careful to not leak the pool `ReadGuard` to prevent deadlocks.
-	pub fn pending<F, T>(&self, at: &BlockId<B::Block>, f: F) -> T where
-		F: FnOnce(txpool::PendingIterator<VerifiedFor<B>, Ready<B>, ScoringAdapter<B>, Listener<B::Hash, Arc<B>>>) -> T,
-	{
-		let ready = self.ready(at);
-		f(self.pool.read().pending(ready))
-	}
-
-	/// Retry to import all verified transactions from given sender.
-	pub fn retry_verification(&self, at: &BlockId<B::Block>, sender: <B::VEx as txpool::VerifiedTransaction>::Sender) -> Result<(), B::Error> {
-		let to_reverify = self.remove_sender(sender);
-		self.submit_at(at, to_reverify.into_iter().map(|ex| Arc::try_unwrap(ex).expect("Removed items have no references").original))?;
-		Ok(())
-	}
-
-	/// Reverify transaction that has been reported incorrect.
-	///
-	/// Returns `Ok(None)` in case the hash is missing, `Err(e)` in case of verification error and new transaction
-	/// reference otherwise.
-	///
-	/// TODO [ToDr] That method is currently unused, should be used together with BlockBuilder
-	/// when we detect that particular transaction has failed.
-	/// In such case we will attempt to remove or re-verify it.
-	pub fn reverify_transaction(&self, at: &BlockId<B::Block>, hash: B::Hash) -> Result<Option<Arc<VerifiedFor<B>>>, B::Error> {
-		let result = self.remove(&[hash], false).pop().expect("One hash passed; one result received; qed");
-		if let Some(ex) = result {
-			self.submit_one(at, Arc::try_unwrap(ex).expect("Removed items have no references").original).map(Some)
-		} else {
-			Ok(None)
-		}
-	}
-
-	/// Retrieve all transactions in the pool grouped by sender.
-	pub fn all(&self) -> AllExtrinsics<B> {
-		use txpool::VerifiedTransaction;
-		let pool = self.pool.read();
-		let all = pool.unordered_pending(AlwaysReady);
-		all.fold(Default::default(), |mut map: AllExtrinsics<B>, tx| {
-			// Map with `null` key is not serializable, so we fallback to default accountId.
-			map.entry(tx.verified.sender().clone())
-				.or_insert_with(Vec::new)
-				// use bytes type to make it serialize nicer.
-				.push(tx.original.clone());
-			map
-		})
-	}
-
-	fn ready<'a, 'b>(&'a self, at: &'b BlockId<B::Block>) -> Ready<'a, 'b, B> {
-		Ready {
-			api: &self.api,
-			rotator: &self.rotator,
-			context: self.api.ready(),
-			at,
-			now: time::Instant::now(),
-		}
-	}
-}
-
- /// A Readiness implementation that returns `Ready` for all transactions.
-pub struct AlwaysReady;
-impl<VEx> txpool::Ready<VEx> for AlwaysReady {
-	fn is_ready(&mut self, _tx: &VEx) -> txpool::Readiness {
-		txpool::Readiness::Ready
-	}
-}
-
-#[cfg(test)]
-pub mod tests {
-	use txpool;
-	use super::{VerifiedFor, ExtrinsicFor, HashOf};
-	use std::collections::HashMap;
-	use std::cmp::Ordering;
-	use {Pool, ChainApi, scoring, Readiness};
-	use keyring::Keyring::{self, *};
-	use codec::Encode;
-	use test_client::runtime::{AccountId, Block, Hash, Index, Extrinsic, Transfer};
-	use runtime_primitives::{generic, traits::{Hash as HashT, BlindCheckable, BlakeTwo256}};
-	use VerifiedTransaction as VerifiedExtrinsic;
-
-	type BlockId = generic::BlockId<Block>;
-
-	#[derive(Clone, Debug)]
-	pub struct VerifiedTransaction {
-		pub hash: Hash,
-		pub sender: AccountId,
-		pub nonce: u64,
-	}
-
-	impl txpool::VerifiedTransaction for VerifiedTransaction {
-		type Hash = Hash;
-		type Sender = AccountId;
-
-		fn hash(&self) -> &Self::Hash {
-			&self.hash
-		}
-
-		fn sender(&self) -> &Self::Sender {
-			&self.sender
-		}
-
-		fn mem_usage(&self) -> usize {
-			256
-		}
-	}
-
-	struct TestApi;
-
-	impl TestApi {
-		fn default() -> Self {
-			TestApi
-		}
-	}
-
-	impl ChainApi for TestApi {
-		type Block = Block;
-		type Hash = Hash;
-		type Sender = AccountId;
-		type Error = txpool::Error;
-		type VEx = VerifiedTransaction;
-		type Ready = HashMap<AccountId, u64>;
-		type Score = u64;
-		type Event = ();
-
-		fn latest_hash(&self) -> HashOf<Self::Block> {
-			1.into()
-		}
-
-		fn verify_transaction(&self, _at: &BlockId, uxt: &ExtrinsicFor<Self>) -> Result<Self::VEx, Self::Error> {
-			let hash = BlakeTwo256::hash(&uxt.encode());
-			let xt = uxt.clone().check()?;
-			Ok(VerifiedTransaction {
-				hash,
-				sender: xt.transfer.from,
-				nonce: xt.transfer.nonce,
-			})
-		}
-
-		fn is_ready(&self, at: &BlockId, nonce_cache: &mut Self::Ready, xt: &VerifiedFor<Self>) -> Readiness {
-			let sender = xt.verified.sender;
-			let next_index = nonce_cache.entry(sender)
-				.or_insert_with(|| index(at, sender));
-
-			let result = match xt.original.transfer.nonce.cmp(&next_index) {
-				Ordering::Greater => Readiness::Future,
-				Ordering::Equal => Readiness::Ready,
-				Ordering::Less => Readiness::Stale,
-			};
-
-			// remember to increment `next_index`
-			*next_index = next_index.saturating_add(1);
-
-			result
-		}
-
-		fn ready(&self) -> Self::Ready {
-			HashMap::default()
-		}
-
-		fn compare(old: &VerifiedFor<Self>, other: &VerifiedFor<Self>) -> Ordering {
-			old.original.transfer.nonce.cmp(&other.original.transfer.nonce)
-		}
-
-		fn choose(old: &VerifiedFor<Self>, new: &VerifiedFor<Self>) -> scoring::Choice {
-			assert!(new.verified.sender == old.verified.sender, "Scoring::choose called with transactions from different senders");
-			if old.original.transfer.nonce == new.original.transfer.nonce {
-				return scoring::Choice::RejectNew;
-			}
-			scoring::Choice::InsertNew
-		}
-
-		fn update_scores(
-			xts: &[txpool::Transaction<VerifiedFor<Self>>],
-			scores: &mut [Self::Score],
-			_change: scoring::Change<()>
-		) {
-			for i in 0..xts.len() {
-				scores[i] = xts[i].original.transfer.amount;
-			}
-		}
-
-		fn should_replace(_old: &VerifiedFor<Self>, _new: &VerifiedFor<Self>) -> scoring::Choice {
-			scoring::Choice::InsertNew
-		}
-	}
-
-	fn index(at: &BlockId, _account: AccountId) -> u64 {
-		(_account[0] as u64) + number_of(at)
-	}
-
-	fn number_of(at: &BlockId) -> u64 {
-		match at {
-			generic::BlockId::Number(n) => *n as u64,
-			_ => 0,
-		}
-	}
-
-	fn uxt(who: Keyring, nonce: Index) -> Extrinsic {
-		let transfer = Transfer {
-			from: who.to_raw_public().into(),
-			to: AccountId::default(),
-			nonce,
-			amount: 1,
-		};
-		let signature = transfer.using_encoded(|e| who.sign(e));
-		Extrinsic {
-			transfer,
-			signature: signature.into(),
-		}
-	}
-
-	fn pool() -> Pool<TestApi> {
-		Pool::new(Default::default(), TestApi::default())
-	}
-
-	#[test]
-	fn submission_should_work() {
-		let pool = pool();
-		assert_eq!(209, index(&BlockId::number(0), Alice.to_raw_public().into()));
-		pool.submit_one(&BlockId::number(0), uxt(Alice, 209)).unwrap();
-
-		let pending: Vec<_> = pool.cull_and_get_pending(&BlockId::number(0), |p| p.map(|a| (*a.sender(), a.original.transfer.nonce)).collect()).unwrap();
-		assert_eq!(pending, vec![(Alice.to_raw_public().into(), 209)]);
-	}
-
-	#[test]
-	fn multiple_submission_should_work() {
-		let pool = pool();
-		pool.submit_one(&BlockId::number(0), uxt(Alice, 209)).unwrap();
-		pool.submit_one(&BlockId::number(0), uxt(Alice, 210)).unwrap();
-
-		let pending: Vec<_> = pool.cull_and_get_pending(&BlockId::number(0), |p| p.map(|a| (*a.sender(), a.original.transfer.nonce)).collect()).unwrap();
-		assert_eq!(pending, vec![(Alice.to_raw_public().into(), 209), (Alice.to_raw_public().into(), 210)]);
-	}
-
-	#[test]
-	fn early_nonce_should_be_culled() {
-		let pool = pool();
-		pool.submit_one(&BlockId::number(0), uxt(Alice, 208)).unwrap();
-
-		let pending: Vec<_> = pool.cull_and_get_pending(&BlockId::number(0), |p| p.map(|a| (*a.sender(), a.original.transfer.nonce)).collect()).unwrap();
-		assert_eq!(pending, vec![]);
-	}
-
-	#[test]
-	fn late_nonce_should_be_queued() {
-		let pool = pool();
-
-		pool.submit_one(&BlockId::number(0), uxt(Alice, 210)).unwrap();
-		let pending: Vec<_> = pool.cull_and_get_pending(&BlockId::number(0), |p| p.map(|a| (*a.sender(), a.original.transfer.nonce)).collect()).unwrap();
-		assert_eq!(pending, vec![]);
-
-		pool.submit_one(&BlockId::number(0), uxt(Alice, 209)).unwrap();
-		let pending: Vec<_> = pool.cull_and_get_pending(&BlockId::number(0), |p| p.map(|a| (*a.sender(), a.original.transfer.nonce)).collect()).unwrap();
-		assert_eq!(pending, vec![(Alice.to_raw_public().into(), 209), (Alice.to_raw_public().into(), 210)]);
-	}
-
-	#[test]
-	fn retrying_verification_might_not_change_anything() {
-		let pool = pool();
-		pool.submit_one(&BlockId::number(0), uxt(Alice, 209)).unwrap();
-		pool.submit_one(&BlockId::number(0), uxt(Alice, 210)).unwrap();
-
-		let pending: Vec<_> = pool.cull_and_get_pending(&BlockId::number(0), |p| p.map(|a| (*a.sender(), a.original.transfer.nonce)).collect()).unwrap();
-		assert_eq!(pending, vec![(Alice.to_raw_public().into(), 209), (Alice.to_raw_public().into(), 210)]);
-
-		pool.retry_verification(&BlockId::number(1), Alice.to_raw_public().into()).unwrap();
-
-		let pending: Vec<_> = pool.cull_and_get_pending(&BlockId::number(0), |p| p.map(|a| (*a.sender(), a.original.transfer.nonce)).collect()).unwrap();
-		assert_eq!(pending, vec![(Alice.to_raw_public().into(), 209), (Alice.to_raw_public().into(), 210)]);
-	}
-
-	#[test]
-	fn should_ban_invalid_transactions() {
-		let pool = pool();
-		let uxt = uxt(Alice, 209);
-		let hash = *pool.submit_one(&BlockId::number(0), uxt.clone()).unwrap().hash();
-		pool.remove(&[hash], true);
-		pool.submit_one(&BlockId::number(0), uxt.clone()).unwrap();
-
-		// when
-		pool.remove(&[hash], false);
-		let pending: Vec<AccountId> = pool.cull_and_get_pending(&BlockId::number(0), |p| p.map(|a| *a.sender()).collect()).unwrap();
-		assert_eq!(pending, vec![]);
-
-		// then
-		pool.submit_one(&BlockId::number(0), uxt.clone()).unwrap_err();
-	}
-}
@@ -0,0 +1,177 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate 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.
+
+// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+
+use super::*;
+
+use keyring::Keyring::{self, *};
+use parity_codec::Encode;
+use txpool::{self, Pool};
+use test_client::runtime::{AccountId, Block, Hash, Index, Extrinsic, Transfer};
+use sr_primitives::{
+	generic::{self, BlockId},
+	traits::{Hash as HashT, BlakeTwo256},
+	transaction_validity::TransactionValidity,
+};
+
+struct TestApi;
+
+impl TestApi {
+	fn default() -> Self {
+		TestApi
+	}
+}
+
+impl txpool::ChainApi for TestApi {
+	type Block = Block;
+	type Hash = Hash;
+	type Error = error::Error;
+
+	fn validate_transaction(&self, at: &BlockId<Self::Block>, uxt: &txpool::ExtrinsicFor<Self>) -> error::Result<TransactionValidity> {
+		let expected = index(at);
+		let requires = if expected == uxt.transfer.nonce {
+			vec![]
+		} else {
+			vec![vec![uxt.transfer.nonce as u8 - 1]]
+		};
+		let provides = vec![vec![uxt.transfer.nonce as u8]];
+
+		Ok(TransactionValidity::Valid(
+			/* priority: */1,
+			requires,
+			provides,
+			/* longevity: */64
+		))
+	}
+
+	fn block_id_to_number(&self, at: &BlockId<Self::Block>) -> error::Result<Option<txpool::NumberFor<Self>>> {
+		Ok(Some(number_of(at)))
+	}
+
+	fn block_id_to_hash(&self, at: &BlockId<Self::Block>) -> error::Result<Option<txpool::BlockHash<Self>>> {
+		Ok(match at {
+			generic::BlockId::Hash(x) => Some(x.clone()),
+			_ => Some(Default::default()),
+		})
+	}
+
+	fn hash(&self, ex: &txpool::ExtrinsicFor<Self>) -> Self::Hash {
+		BlakeTwo256::hash(&ex.encode())
+	}
+
+}
+
+fn index(at: &BlockId<Block>) -> u64 {
+	209 + number_of(at)
+}
+
+fn number_of(at: &BlockId<Block>) -> u64 {
+	match at {
+		generic::BlockId::Number(n) => *n as u64,
+		_ => 0,
+	}
+}
+
+fn uxt(who: Keyring, nonce: Index) -> Extrinsic {
+	let transfer = Transfer {
+		from: who.to_raw_public().into(),
+		to: AccountId::default(),
+		nonce,
+		amount: 1,
+	};
+	let signature = transfer.using_encoded(|e| who.sign(e));
+	Extrinsic {
+		transfer,
+		signature: signature.into(),
+	}
+}
+
+fn pool() -> Pool<TestApi> {
+	Pool::new(Default::default(), TestApi::default())
+}
+
+#[test]
+fn submission_should_work() {
+	let pool = pool();
+	assert_eq!(209, index(&BlockId::number(0)));
+	pool.submit_one(&BlockId::number(0), uxt(Alice, 209)).unwrap();
+
+	let pending: Vec<_> = pool.ready(|p| p.map(|a| a.data.raw.transfer.nonce).collect());
+	assert_eq!(pending, vec![209]);
+}
+
+#[test]
+fn multiple_submission_should_work() {
+	let pool = pool();
+	pool.submit_one(&BlockId::number(0), uxt(Alice, 209)).unwrap();
+	pool.submit_one(&BlockId::number(0), uxt(Alice, 210)).unwrap();
+
+	let pending: Vec<_> = pool.ready(|p| p.map(|a| a.data.raw.transfer.nonce).collect());
+	assert_eq!(pending, vec![209, 210]);
+}
+
+#[test]
+fn early_nonce_should_be_culled() {
+	let pool = pool();
+	pool.submit_one(&BlockId::number(0), uxt(Alice, 208)).unwrap();
+
+	let pending: Vec<_> = pool.ready(|p| p.map(|a| a.data.raw.transfer.nonce).collect());
+	assert_eq!(pending, Vec::<Index>::new());
+}
+
+#[test]
+fn late_nonce_should_be_queued() {
+	let pool = pool();
+
+	pool.submit_one(&BlockId::number(0), uxt(Alice, 210)).unwrap();
+	let pending: Vec<_> = pool.ready(|p| p.map(|a| a.data.raw.transfer.nonce).collect());
+	assert_eq!(pending, Vec::<Index>::new());
+
+	pool.submit_one(&BlockId::number(0), uxt(Alice, 209)).unwrap();
+	let pending: Vec<_> = pool.ready(|p| p.map(|a| a.data.raw.transfer.nonce).collect());
+	assert_eq!(pending, vec![209, 210]);
+}
+
+#[test]
+fn prune_tags_should_work() {
+	let pool = pool();
+	pool.submit_one(&BlockId::number(0), uxt(Alice, 209)).unwrap();
+	pool.submit_one(&BlockId::number(0), uxt(Alice, 210)).unwrap();
+
+	let pending: Vec<_> = pool.ready(|p| p.map(|a| a.data.raw.transfer.nonce).collect());
+	assert_eq!(pending, vec![209, 210]);
+
+	pool.prune_tags(&BlockId::number(1), vec![vec![209]]).unwrap();
+
+	let pending: Vec<_> = pool.ready(|p| p.map(|a| a.data.raw.transfer.nonce).collect());
+	assert_eq!(pending, vec![210]);
+}
+
+#[test]
+fn should_ban_invalid_transactions() {
+	let pool = pool();
+	let uxt = uxt(Alice, 209);
+	let hash = pool.submit_one(&BlockId::number(0), uxt.clone()).unwrap();
+	pool.remove_invalid(&[hash]);
+	pool.submit_one(&BlockId::number(0), uxt.clone()).unwrap_err();
+
+	// when
+	let pending: Vec<_> = pool.ready(|p| p.map(|a| a.data.raw.transfer.nonce).collect());
+	assert_eq!(pending, Vec::<Index>::new());
+
+	// then
+	pool.submit_one(&BlockId::number(0), uxt.clone()).unwrap_err();
+}
@@ -4,22 +4,22 @@ version = "0.1.0"
 authors = ["Parity Technologies <admin@parity.io>"]

 [dependencies]
-futures = "0.1.17"
-parking_lot = "0.4"
-tokio = "0.1.7"
 error-chain = "0.12"
-log = "0.4"
 exit-future = "0.1"
-rhododendron = "0.3"
+futures = "0.1.17"
+log = "0.4"
 node-primitives = { path = "../primitives" }
 node-runtime = { path = "../runtime" }
-node-transaction-pool = { path = "../transaction-pool" }
-substrate-bft = { path = "../../core/bft" }
 parity-codec = "2.0"
-substrate-primitives = { path = "../../core/primitives" }
-substrate-client = { path = "../../core/client" }
+parking_lot = "0.4"
+rhododendron = "0.3"
 sr-primitives = { path = "../../core/sr-primitives" }
 srml-system = { path = "../../srml/system" }
+substrate-bft = { path = "../../core/bft" }
+substrate-client = { path = "../../core/client" }
+substrate-primitives = { path = "../../core/primitives" }
+substrate-transaction-pool = { path = "../../core/transaction-pool" }
+tokio = "0.1.7"

 [dev-dependencies]
 substrate-keyring = { path = "../../core/keyring" }
@@ -16,25 +16,25 @@

 //! This service uses BFT consensus provided by the substrate.

-extern crate parking_lot;
-extern crate node_transaction_pool as transaction_pool;
 extern crate node_runtime;
 extern crate node_primitives;

-extern crate substrate_bft as bft;
 extern crate parity_codec as codec;
-extern crate substrate_primitives as primitives;
 extern crate sr_primitives as runtime_primitives;
 extern crate srml_system;
+extern crate substrate_bft as bft;
 extern crate substrate_client as client;
+extern crate substrate_primitives as primitives;
+extern crate substrate_transaction_pool as transaction_pool;

 extern crate exit_future;
-extern crate tokio;
+extern crate futures;
+extern crate parking_lot;
 extern crate rhododendron;
+extern crate tokio;

 #[macro_use]
 extern crate error_chain;
-extern crate futures;

 #[macro_use]
 extern crate log;
@@ -51,10 +51,10 @@ use codec::{Decode, Encode};
 use node_primitives::{AccountId, Timestamp, SessionKey, InherentData};
 use node_runtime::Runtime;
 use primitives::{AuthorityId, ed25519, Blake2Hasher};
-use runtime_primitives::traits::{Block as BlockT, Hash as HashT, Header as HeaderT, As};
+use runtime_primitives::traits::{Block as BlockT, Hash as HashT, Header as HeaderT, As, BlockNumberToHash};
 use runtime_primitives::generic::{BlockId, Era};
 use srml_system::Trait as SystemT;
-use transaction_pool::{TransactionPool, Client as TPClient};
+use transaction_pool::txpool::{self, Pool as TransactionPool};
 use tokio::runtime::TaskExecutor;
 use tokio::timer::Delay;

@@ -95,7 +95,7 @@ pub trait AuthoringApi:
 	/// The block used for this API type.
 	type Block: BlockT;
 	/// The error used by this API type.
-	type Error;
+	type Error: std::error::Error;

 	/// Build a block on top of the given, with inherent extrinsics pre-pushed.
 	fn build_block<F: FnMut(&mut BlockBuilder<Self::Block>) -> ()>(
@@ -166,13 +166,14 @@ pub trait Network {
 }

 /// Proposer factory.
-pub struct ProposerFactory<N, C> where
-	C: AuthoringApi + TPClient,
+pub struct ProposerFactory<N, C, A> where
+	C: AuthoringApi,
+	A: txpool::ChainApi,
 {
 	/// The client instance.
 	pub client: Arc<C>,
 	/// The transaction pool.
-	pub transaction_pool: Arc<TransactionPool<C>>,
+	pub transaction_pool: Arc<TransactionPool<A>>,
 	/// The backing network handle.
 	pub network: N,
 	/// handle to remote task executor
@@ -183,14 +184,15 @@ pub struct ProposerFactory<N, C> where
 	pub force_delay: Timestamp,
 }

-impl<N, C> bft::Environment<<C as AuthoringApi>::Block> for ProposerFactory<N, C> where
+impl<N, C, A> bft::Environment<<C as AuthoringApi>::Block> for ProposerFactory<N, C, A> where
 	N: Network<Block=<C as AuthoringApi>::Block>,
-	C: AuthoringApi + TPClient<Block=<C as AuthoringApi>::Block>,
+	C: AuthoringApi + BlockNumberToHash,
+	A: txpool::ChainApi<Block=<C as AuthoringApi>::Block>,
 	<<C as AuthoringApi>::Block as BlockT>::Hash:
 		Into<<Runtime as SystemT>::Hash> + PartialEq<primitives::H256> + Into<primitives::H256>,
 	Error: From<<C as AuthoringApi>::Error>
 {
-	type Proposer = Proposer<C>;
+	type Proposer = Proposer<C, A>;
 	type Input = N::Input;
 	type Output = N::Output;
 	type Error = Error;
@@ -240,7 +242,7 @@ impl<N, C> bft::Environment<<C as AuthoringApi>::Block> for ProposerFactory<N, C
 }

 /// The proposer logic.
-pub struct Proposer<C: AuthoringApi + TPClient> {
+pub struct Proposer<C: AuthoringApi, A: txpool::ChainApi> {
 	client: Arc<C>,
 	start: Instant,
 	local_key: Arc<ed25519::Pair>,
@@ -248,13 +250,13 @@ pub struct Proposer<C: AuthoringApi + TPClient> {
 	parent_id: BlockId<<C as AuthoringApi>::Block>,
 	parent_number: <<<C as AuthoringApi>::Block as BlockT>::Header as HeaderT>::Number,
 	random_seed: <<C as AuthoringApi>::Block as BlockT>::Hash,
-	transaction_pool: Arc<TransactionPool<C>>,
+	transaction_pool: Arc<TransactionPool<A>>,
 	offline: SharedOfflineTracker,
 	validators: Vec<AccountId>,
 	minimum_timestamp: u64,
 }

-impl<C: AuthoringApi + TPClient> Proposer<C> {
+impl<C: AuthoringApi, A: txpool::ChainApi> Proposer<C, A> {
 	fn primary_index(&self, round_number: usize, len: usize) -> usize {
 		use primitives::uint::U256;

@@ -265,8 +267,9 @@ impl<C: AuthoringApi + TPClient> Proposer<C> {
 	}
 }

-impl<C> bft::Proposer<<C as AuthoringApi>::Block> for Proposer<C> where
-	C: AuthoringApi + TPClient<Block=<C as AuthoringApi>::Block>,
+impl<C, A> bft::Proposer<<C as AuthoringApi>::Block> for Proposer<C, A> where
+	C: AuthoringApi + BlockNumberToHash,
+	A: txpool::ChainApi<Block=<C as AuthoringApi>::Block>,
 	<<C as AuthoringApi>::Block as BlockT>::Hash:
 		Into<<Runtime as SystemT>::Hash> + PartialEq<primitives::H256> + Into<primitives::H256>,
 	error::Error: From<<C as AuthoringApi>::Error>
@@ -307,27 +310,26 @@ impl<C> bft::Proposer<<C as AuthoringApi>::Block> for Proposer<C> where
 			inherent_data,
 			|block_builder| {
 				let mut unqueue_invalid = Vec::new();
-				let result = self.transaction_pool.cull_and_get_pending(&BlockId::hash(self.parent_hash), |pending_iterator| {
+				self.transaction_pool.ready(|pending_iterator| {
 					let mut pending_size = 0;
 					for pending in pending_iterator {
-						if pending_size + pending.verified.encoded_size() >= MAX_TRANSACTIONS_SIZE { break }
+						// TODO [ToDr] Probably get rid of it, and validate in runtime.
+						let encoded_size = pending.data.raw.encode().len();
+						if pending_size + encoded_size >= MAX_TRANSACTIONS_SIZE { break }

-						match block_builder.push_extrinsic(pending.original.clone()) {
+						match block_builder.push_extrinsic(pending.data.raw.clone()) {
 							Ok(()) => {
-								pending_size += pending.verified.encoded_size();
+								pending_size += encoded_size;
 							}
 							Err(e) => {
 								trace!(target: "transaction-pool", "Invalid transaction: {}", e);
-								unqueue_invalid.push(pending.verified.hash().clone());
+								unqueue_invalid.push(pending.hash.clone());
 							}
 						}
 					}
 				});
-				if let Err(e) = result {
-					warn!("Unable to get the pending set: {:?}", e);
-				}

-				self.transaction_pool.remove(&unqueue_invalid, false);
+				self.transaction_pool.remove_invalid(&unqueue_invalid);
 			})?;

 		info!("Proposing block [number: {}; hash: {}; parent_hash: {}; extrinsics: [{}]]",
@@ -440,24 +442,22 @@ impl<C> bft::Proposer<<C as AuthoringApi>::Block> for Proposer<C> where
 		use runtime_primitives::bft::{MisbehaviorKind, MisbehaviorReport};
 		use node_runtime::{Call, UncheckedExtrinsic, ConsensusCall};

-		let local_id = self.local_key.public().0.into();
 		let mut next_index = {
-			let cur_index = self.transaction_pool.cull_and_get_pending(&BlockId::hash(self.parent_hash), |pending| pending
-				.filter(|tx| tx.verified.sender == local_id)
-				.last()
-				.map(|tx| Ok(tx.verified.index()))
-				.unwrap_or_else(|| self.client.account_nonce(&self.parent_id, &local_id))
-				.map_err(Error::from)
-			);
+			let local_id = self.local_key.public().0;
+			// let cur_index = self.transaction_pool.cull_and_get_pending(&BlockId::hash(self.parent_hash), |pending| pending
+			// 	.filter(|tx| tx.verified.sender == local_id)
+			// 	.last()
+			// 	.map(|tx| Ok(tx.verified.index()))
+			// 	.unwrap_or_else(|| self.client.account_nonce(&self.parent_id, local_id))
+			// 	.map_err(Error::from)
+			// );
+			// TODO [ToDr] Use pool data
+			let cur_index: Result<u64> = self.client.account_nonce(&self.parent_id, &local_id).map_err(Error::from);

 			match cur_index {
-				Ok(Ok(cur_index)) => cur_index + 1,
-				Ok(Err(e)) => {
-					warn!(target: "consensus", "Error computing next transaction index: {}", e);
-					return;
-				}
+				Ok(cur_index) => cur_index + 1,
 				Err(e) => {
-					warn!(target: "consensus", "Error computing next transaction index: {}", e);
+					warn!(target: "consensus", "Error computing next transaction index: {:?}", e);
 					return;
 				}
 			}
@@ -488,8 +488,9 @@ impl<C> bft::Proposer<<C as AuthoringApi>::Block> for Proposer<C> where
 			};
 			let uxt: <<C as AuthoringApi>::Block as BlockT>::Extrinsic = Decode::decode(&mut extrinsic.encode().as_slice()).expect("Encoded extrinsic is valid");
 			let hash = BlockId::<<C as AuthoringApi>::Block>::hash(self.parent_hash);
-			self.transaction_pool.submit_one(&hash, uxt)
-				.expect("locally signed extrinsic is valid; qed");
+			if let Err(e) = self.transaction_pool.submit_one(&hash, uxt) {
+				warn!("Error importing misbehavior report: {:?}", e);
+			}
 		}
 	}

@@ -26,9 +26,9 @@ use bft::{self, BftService};
 use client::{BlockchainEvents, ChainHead, BlockBody};
 use ed25519;
 use futures::prelude::*;
-use transaction_pool::{TransactionPool, Client as TPClient};
+use transaction_pool::txpool::{Pool as TransactionPool, ChainApi as PoolChainApi};
 use primitives;
-use runtime_primitives::traits::{Block as BlockT, Header as HeaderT};
+use runtime_primitives::traits::{Block as BlockT, Header as HeaderT, BlockNumberToHash};

 use tokio::executor::current_thread::TaskExecutor as LocalThreadHandle;
 use tokio::runtime::TaskExecutor as ThreadPoolHandle;
@@ -72,18 +72,19 @@ pub struct Service {

 impl Service {
 	/// Create and start a new instance.
-	pub fn new<A, C, N>(
+	pub fn new<A, P, C, N>(
 		client: Arc<C>,
 		api: Arc<A>,
 		network: N,
-		transaction_pool: Arc<TransactionPool<A>>,
+		transaction_pool: Arc<TransactionPool<P>>,
 		thread_pool: ThreadPoolHandle,
 		key: ed25519::Pair,
 		block_delay: u64,
 	) -> Service
 		where
-			A: AuthoringApi + TPClient<Block = <A as AuthoringApi>::Block> + 'static,
 			error::Error: From<<A as AuthoringApi>::Error>,
+			A: AuthoringApi + BlockNumberToHash + 'static,
+			P: PoolChainApi<Block = <A as AuthoringApi>::Block> + 'static,
 			C: BlockchainEvents<<A as AuthoringApi>::Block>
 				+ ChainHead<<A as AuthoringApi>::Block>
 				+ BlockBody<<A as AuthoringApi>::Block>,
@@ -4,27 +4,27 @@ version = "0.1.0"
 authors = ["Parity Technologies <admin@parity.io>"]

 [dependencies]
-parking_lot = "0.4"
 error-chain = "0.12"
+hex-literal = "0.1"
 lazy_static = "1.0"
 log = "0.4"
-slog = "^2"
-tokio = "0.1.7"
-hex-literal = "0.1"
-parity-codec = { version = "2.0" }
+node-consensus = { path = "../consensus" }
+node-executor = { path = "../executor" }
+node-network = { path = "../network" }
 node-primitives = { path = "../primitives" }
 node-runtime = { path = "../runtime" }
-node-executor = { path = "../executor" }
-node-consensus = { path = "../consensus" }
-node-network = { path = "../network" }
-node-transaction-pool = { path = "../transaction-pool" }
+parity-codec = { version = "2.0" }
+parking_lot = "0.4"
+slog = "^2"
 sr-io = { path = "../../core/sr-io" }
 sr-primitives = { path = "../../core/sr-primitives" }
-substrate-primitives = { path = "../../core/primitives" }
-substrate-network = { path = "../../core/network" }
 substrate-client = { path = "../../core/client" }
+substrate-network = { path = "../../core/network" }
+substrate-primitives = { path = "../../core/primitives" }
 substrate-service = { path = "../../core/service" }
 substrate-telemetry = { path = "../../core/telemetry" }
+substrate-transaction-pool = { path = "../../core/transaction-pool" }
+tokio = "0.1.7"

 [dev-dependencies]
 substrate-service-test = { path = "../../core/service/test" }
@@ -22,12 +22,12 @@ extern crate node_primitives;
 extern crate node_runtime;
 extern crate node_executor;
 extern crate node_network;
-extern crate node_transaction_pool as transaction_pool;
 extern crate node_consensus as consensus;
-extern crate substrate_primitives as primitives;
-extern crate substrate_network as network;
 extern crate substrate_client as client;
+extern crate substrate_network as network;
+extern crate substrate_primitives as primitives;
 extern crate substrate_service as service;
+extern crate substrate_transaction_pool as transaction_pool;
 extern crate parity_codec as codec;
 extern crate tokio;
 #[cfg(test)]
@@ -51,13 +51,12 @@ pub mod chain_spec;

 use std::sync::Arc;
 use codec::Decode;
-use transaction_pool::TransactionPool;
+use transaction_pool::txpool::{Pool as TransactionPool};
 use node_primitives::{Block, Hash, Timestamp, BlockId};
 use node_runtime::{GenesisConfig, BlockPeriod, StorageValue, Runtime};
 use client::Client;
 use consensus::AuthoringApi;
 use node_network::{Protocol as DemoProtocol, consensus::ConsensusNetwork};
-use transaction_pool::Client as TPApi;
 use tokio::runtime::TaskExecutor;
 use service::FactoryFullConfiguration;
 use primitives::{Blake2Hasher, storage::StorageKey, twox_128};
@@ -75,7 +74,7 @@ pub type NetworkService = network::Service<Block, <Factory as service::ServiceFa
 /// A collection of type to generalise specific components over full / light client.
 pub trait Components: service::Components {
 	/// Demo API.
-	type Api: 'static + AuthoringApi + TPApi + Send + Sync;
+	type Api: 'static + AuthoringApi + Send + Sync;
 	/// Client backend.
 	type Backend: 'static + client::backend::Backend<Block, Blake2Hasher>;
 	/// Client executor.
@@ -109,21 +108,21 @@ impl service::ServiceFactory for Factory {
 	type ExtrinsicHash = Hash;
 	type NetworkProtocol = DemoProtocol;
 	type RuntimeDispatch = node_executor::Executor;
-	type FullTransactionPoolApi = transaction_pool::ChainApi<service::FullClient<Self>>;
-	type LightTransactionPoolApi = transaction_pool::ChainApi<service::LightClient<Self>>;
+	type FullTransactionPoolApi = transaction_pool::ChainApi<service::FullBackend<Self>, service::FullExecutor<Self>, Block>;
+	type LightTransactionPoolApi = transaction_pool::ChainApi<service::LightBackend<Self>, service::LightExecutor<Self>, Block>;
 	type Genesis = GenesisConfig;
 	type Configuration = CustomConfiguration;
 	type FullService = Service<service::FullComponents<Self>>;
 	type LightService = Service<service::LightComponents<Self>>;

 	fn build_full_transaction_pool(config: TransactionPoolOptions, client: Arc<service::FullClient<Self>>)
-		-> Result<TransactionPool<service::FullClient<Self>>, Error>
+		-> Result<TransactionPool<Self::FullTransactionPoolApi>, Error>
 	{
 		Ok(TransactionPool::new(config, transaction_pool::ChainApi::new(client)))
 	}

 	fn build_light_transaction_pool(config: TransactionPoolOptions, client: Arc<service::LightClient<Self>>)
-		-> Result<TransactionPool<service::LightClient<Self>>, Error>
+		-> Result<TransactionPool<Self::LightTransactionPoolApi>, Error>
 	{
 		Ok(TransactionPool::new(config, transaction_pool::ChainApi::new(client)))
 	}
@@ -1,16 +0,0 @@
-[package]
-name = "node-transaction-pool"
-version = "0.1.0"
-authors = ["Parity Technologies <admin@parity.io>"]
-
-[dependencies]
-log = "0.4"
-error-chain = "0.12"
-node-primitives = { path = "../primitives" }
-node-runtime = { path = "../runtime" }
-substrate-client = { path = "../../core/client" }
-parity-codec = "2.0"
-substrate-keyring = { path = "../../core/keyring" }
-substrate-transaction-pool = { path = "../../core/transaction-pool" }
-substrate-primitives = { path = "../../core/primitives" }
-sr-primitives = { path = "../../core/sr-primitives" }
@@ -1,73 +0,0 @@
-// Copyright 2018 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate 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.
-
-// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-use transaction_pool;
-use primitives::Hash;
-use runtime::{Address, UncheckedExtrinsic};
-use client;
-
-error_chain! {
-	links {
-		Client(client::error::Error, client::error::ErrorKind);
-		Pool(transaction_pool::Error, transaction_pool::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("Inherent transactions cannot be queued."),
-		}
-		/// Attempted to queue a transaction with bad signature.
-		BadSignature(e: &'static str) {
-			description("Transaction had bad signature."),
-			display("Transaction had bad signature: {}", e),
-		}
-		/// 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()),
-		}
-		/// Runtime failure.
-		UnrecognisedAddress(who: Address) {
-			description("Unrecognised address in extrinsic"),
-			display("Unrecognised address in extrinsic: {}", who),
-		}
-		/// Extrinsic too large
-		TooLarge(got: usize, max: usize) {
-			description("Extrinsic too large"),
-			display("Extrinsic is too large ({} > {})", got, max),
-		}
-	}
-}
-
-impl transaction_pool::IntoPoolError for Error {
-	fn into_pool_error(self) -> ::std::result::Result<transaction_pool::Error, Self> {
-		match self {
-			Error(ErrorKind::Pool(e), c) => Ok(transaction_pool::Error(e, c)),
-			e => Err(e),
-		}
-	}
-}
@@ -1,275 +0,0 @@
-// Copyright 2018 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate 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.
-
-// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
-extern crate substrate_client as client;
-extern crate parity_codec as codec;
-extern crate substrate_transaction_pool as transaction_pool;
-extern crate substrate_primitives;
-extern crate sr_primitives;
-extern crate node_runtime as runtime;
-extern crate node_primitives as primitives;
-
-#[cfg(test)]
-extern crate substrate_keyring;
-
-#[macro_use]
-extern crate error_chain;
-
-#[macro_use]
-extern crate log;
-
-mod error;
-
-use std::{
-	cmp::Ordering,
-	collections::HashMap,
-	sync::Arc,
-};
-
-use codec::{Decode, Encode};
-use client::{Client as SubstrateClient, CallExecutor};
-use client::runtime_api::OldTxQueue;
-use transaction_pool::{Readiness, scoring::{Change, Choice}, VerifiedFor, ExtrinsicFor};
-use primitives::{AccountId, Hash, Index};
-use runtime::{Address, UncheckedExtrinsic};
-use substrate_primitives::{Blake2Hasher};
-use sr_primitives::generic::BlockId;
-use sr_primitives::traits::{
-	Bounded, Checkable, Block as BlockT, Hash as HashT, Header as HeaderT, BlakeTwo256, Lookup, CurrentHeight,
-	BlockNumberToHash
-};
-
-pub use transaction_pool::{Options, Status, LightStatus, VerifiedTransaction as VerifiedTransactionOps};
-pub use error::{Error, ErrorKind, Result};
-
-/// Maximal size of a single encoded extrinsic.
-const MAX_TRANSACTION_SIZE: usize = 4 * 1024 * 1024;
-
-/// Local client abstraction for the transaction-pool.
-pub trait Client:
-	Send
-	+ Sync
-	+ CurrentHeight<BlockNumber=<<<Self as Client>::Block as BlockT>::Header as HeaderT>::Number>
-	+ BlockNumberToHash<BlockNumber=<<<Self as Client>::Block as BlockT>::Header as HeaderT>::Number, Hash=<<Self as Client>::Block as BlockT>::Hash>
-	+ OldTxQueue<<Self as Client>::Block>
-{
-	/// The block used for this API type.
-	type Block: BlockT;
-}
-
-impl<B, E, Block> Client for SubstrateClient<B, E, Block> where
-	B: client::backend::Backend<Block, Blake2Hasher> + Send + Sync + 'static,
-	E: CallExecutor<Block, Blake2Hasher> + Send + Sync + Clone + 'static,
-	Block: BlockT,
-{
-	type Block = Block;
-}
-
-/// Type alias for the transaction pool.
-pub type TransactionPool<C> = transaction_pool::Pool<ChainApi<C>>;
-
-/// A verified transaction which should be includable and non-inherent.
-#[derive(Clone, Debug)]
-pub struct VerifiedTransaction {
-	/// Transaction hash.
-	pub hash: Hash,
-	/// Transaction sender.
-	pub sender: AccountId,
-	/// Transaction index.
-	pub index: Index,
-	encoded_size: usize,
-}
-
-impl VerifiedTransaction {
-	/// Get the 256-bit hash of this transaction.
-	pub fn hash(&self) -> &Hash {
-		&self.hash
-	}
-
-	/// Get the account ID of the sender of this transaction.
-	pub fn index(&self) -> Index {
-		self.index
-	}
-
-	/// Get encoded size of the transaction.
-	pub fn encoded_size(&self) -> usize {
-		self.encoded_size
-	}
-}
-
-impl transaction_pool::VerifiedTransaction for VerifiedTransaction {
-	type Hash = Hash;
-	type Sender = AccountId;
-
-	fn hash(&self) -> &Self::Hash {
-		&self.hash
-	}
-
-	fn sender(&self) -> &Self::Sender {
-		&self.sender
-	}
-
-	fn mem_usage(&self) -> usize {
-		self.encoded_size // TODO
-	}
-}
-
-/// The transaction pool logic.
-pub struct ChainApi<C: Client> {
-	api: Arc<C>,
-}
-
-impl<C: Client> ChainApi<C> {
-	/// Create a new instance.
-	pub fn new(api: Arc<C>) -> Self {
-		ChainApi {
-			api,
-		}
-	}
-}
-
-/// "Chain" context (used for checking transactions) which uses data local to our node/transaction pool.
-///
-/// This is due for removal when #721 lands
-pub struct LocalContext<'a, A: 'a>(&'a Arc<A>);
-impl<'a, C: 'a + Client> CurrentHeight for LocalContext<'a, C> {
-	type BlockNumber = <C as CurrentHeight>::BlockNumber;
-	fn current_height(&self) -> Self::BlockNumber {
-		self.0.current_height()
-	}
-}
-impl<'a, C: 'a + Client> BlockNumberToHash for LocalContext<'a, C> {
-	type BlockNumber = <C as BlockNumberToHash>::BlockNumber;
-	type Hash = <C as BlockNumberToHash>::Hash;
-	fn block_number_to_hash(&self, n: Self::BlockNumber) -> Option<Self::Hash> {
-		self.0.block_number_to_hash(n)
-	}
-}
-impl<'a, C: 'a + Client> Lookup for LocalContext<'a, C> {
-	type Source = Address;
-	type Target = AccountId;
-	fn lookup(&self, a: Address) -> ::std::result::Result<AccountId, &'static str> {
-		self.0.lookup_address(&BlockId::number(self.current_height()), &a).unwrap_or(None).ok_or("error with lookup")
-	}
-}
-
-impl<C: Client> transaction_pool::ChainApi for ChainApi<C> {
-	type Block = C::Block;
-	type Hash = Hash;
-	type Sender = AccountId;
-	type VEx = VerifiedTransaction;
-	type Ready = HashMap<AccountId, u64>;
-	type Error = Error;
-	type Score = u64;
-	type Event = ();
-
-	fn latest_hash(&self) -> <C::Block as BlockT>::Hash {
-		self.api.block_number_to_hash(self.api.current_height()).expect("Latest block number always has a hash; qed")
-	}
-
-	fn verify_transaction(&self, _at: &BlockId<Self::Block>, xt: &ExtrinsicFor<Self>) -> Result<Self::VEx> {
-		let encoded = xt.encode();
-		let uxt = UncheckedExtrinsic::decode(&mut encoded.as_slice()).ok_or_else(|| ErrorKind::InvalidExtrinsicFormat)?;
-		if !uxt.is_signed() {
-			bail!(ErrorKind::IsInherent(uxt))
-		}
-
-		let (encoded_size, hash) = (encoded.len(), BlakeTwo256::hash(&encoded));
-		if encoded_size > MAX_TRANSACTION_SIZE {
-			bail!(ErrorKind::TooLarge(encoded_size, MAX_TRANSACTION_SIZE));
-		}
-
-		debug!(target: "transaction-pool", "Transaction submitted: {}", ::substrate_primitives::hexdisplay::HexDisplay::from(&encoded));
-		let checked = uxt.clone().check(&LocalContext(&self.api))?;
-		let (sender, index) = checked.signed.expect("function previously bailed unless uxt.is_signed(); qed");
-
-
-		if encoded_size < 1024 {
-			debug!(target: "transaction-pool", "Transaction verified: {} => {:?}", hash, uxt);
-		} else {
-			debug!(target: "transaction-pool", "Transaction verified: {} ({} bytes is too large to display)", hash, encoded_size);
-		}
-
-		Ok(VerifiedTransaction {
-			index,
-			sender,
-			hash,
-			encoded_size,
-		})
-	}
-
-	fn ready(&self) -> Self::Ready {
-		HashMap::default()
-	}
-
-	fn is_ready(&self, at: &BlockId<Self::Block>, known_nonces: &mut Self::Ready, xt: &VerifiedFor<Self>) -> Readiness {
-		let sender = xt.verified.sender().clone();
-		trace!(target: "transaction-pool", "Checking readiness of {} (from {})", xt.verified.hash, sender);
-
-		// TODO: find a way to handle index error properly -- will need changes to
-		// transaction-pool trait.
-		let api = &self.api;
-		let next_index = known_nonces.entry(sender)
-			.or_insert_with(|| api.account_nonce(at, &sender).ok().unwrap_or_else(Bounded::max_value));
-
-		trace!(target: "transaction-pool", "Next index for sender is {}; xt index is {}", next_index, xt.verified.index);
-
-		let result = match xt.verified.index.cmp(&next_index) {
-			// TODO: this won't work perfectly since accounts can now be killed, returning the nonce
-			// to zero.
-			// We should detect if the index was reset and mark all transactions as `Stale` for cull to work correctly.
-			// Otherwise those transactions will keep occupying the queue.
-			// Perhaps we could mark as stale if `index - state_index` > X?
-			Ordering::Greater => Readiness::Future,
-			Ordering::Equal => Readiness::Ready,
-			// TODO [ToDr] Should mark transactions referencing too old blockhash as `Stale` as well.
-			Ordering::Less => Readiness::Stale,
-		};
-
-		// remember to increment `next_index`
-		*next_index = next_index.saturating_add(1);
-
-		result
-	}
-
-	fn compare(old: &VerifiedFor<Self>, other: &VerifiedFor<Self>) -> Ordering {
-		old.verified.index().cmp(&other.verified.index())
-	}
-
-	fn choose(old: &VerifiedFor<Self>, new: &VerifiedFor<Self>) -> Choice {
-		if old.verified.index() == new.verified.index() {
-			return Choice::ReplaceOld;
-		}
-		Choice::InsertNew
-	}
-
-	fn update_scores(
-		xts: &[transaction_pool::Transaction<VerifiedFor<Self>>],
-		scores: &mut [Self::Score],
-		_change: Change<()>
-	) {
-		for i in 0..xts.len() {
-			// all the same score since there are no fees.
-			// TODO: prioritize things like misbehavior or fishermen reports
-			scores[i] = 1;
-		}
-	}
-
-	fn should_replace(_old: &VerifiedFor<Self>, _new: &VerifiedFor<Self>) -> Choice {
-		// Don't allow new transactions if we are reaching the limit.
-		Choice::RejectNew
-	}
-}
@@ -224,11 +224,11 @@ impl<

 	/// Check a given transaction for validity. This doesn't execute any
 	/// side-effects; it merely checks whether the transaction would panic if it were included or not.
-	/// 
+	///
 	/// Changes made to the storage should be discarded.
 	pub fn validate_transaction(uxt: Block::Extrinsic) -> TransactionValidity {
 		let encoded_len = uxt.encode().len();
-		
+
 		let xt = match uxt.check(&Default::default()) {
 			// Checks out. Carry on.
 			Ok(xt) => xt,
@@ -259,8 +259,13 @@ impl<
 				deps.push((sender, expected_index).encode());
 				expected_index = expected_index + One::one();
 			}
-			
-			TransactionValidity::Valid(encoded_len as TransactionPriority, deps, vec![(sender, *index).encode()], TransactionLongevity::max_value())
+
+			TransactionValidity::Valid(
+				/*priority: */encoded_len as TransactionPriority,
+				/*requires: */deps,
+				/*provides: */vec![(sender, *index).encode()],
+				/*longevity: */TransactionLongevity::max_value(),
+			)
 		} else {
 			return TransactionValidity::Invalid
 		}