Begin with something

Cargo.toml

@@ -1,5 +1,6 @@
 [workspace]
 members = [
+	"client/consensus/aura",
 	"client/consensus/common",
 	"client/consensus/relay-chain",
 	"client/network",

client/consensus/aura/Cargo.toml

@@ -0,0 +1,37 @@
+[package]
+name = "cumulus-client-consensus-aura"
+description = "AURA consensus algorithm for parachains"
+version = "0.1.0"
+authors = ["Parity Technologies <[email protected]>"]
+edition = "2018"
+
+[dependencies]
+# Substrate dependencies
+sp-consensus = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-inherents = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-blockchain = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-block-builder = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-consensus-aura = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-client-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-consensus-aura = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-consensus-slots = { git = "https://github.com/paritytech/substrate", branch = "master" }
+substrate-prometheus-endpoint = { git = "https://github.com/paritytech/substrate", branch = "master" }
+
+# Polkadot dependencies
+polkadot-service = { git = "https://github.com/paritytech/polkadot", branch = "master", features = [ "real-overseer" ] }
+
+# Cumulus dependencies
+cumulus-client-consensus-common = { path = "../common" }
+cumulus-primitives-core = { path = "../../../primitives/core" }
+cumulus-primitives-parachain-inherent = { path = "../../../primitives/parachain-inherent" }
+
+# Other deps
+futures = { version = "0.3.8", features = ["compat"] }
+codec = { package = "parity-scale-codec", version = "2.0.0", features = [ "derive" ] }
+tracing = "0.1.22"
+async-trait = "0.1.42"
+parking_lot = "0.9"

client/consensus/aura/src/import_queue.rs

@@ -0,0 +1,144 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Cumulus.
+
+// Cumulus 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.
+
+// Cumulus 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 Cumulus.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::{marker::PhantomData, sync::Arc};
+
+use sp_api::ProvideRuntimeApi;
+use sp_block_builder::BlockBuilder as BlockBuilderApi;
+use sp_blockchain::Result as ClientResult;
+use sp_consensus::{
+	error::Error as ConsensusError,
+	import_queue::{BasicQueue, CacheKeyId, Verifier as VerifierT},
+	BlockImport, BlockImportParams, BlockOrigin, ForkChoiceStrategy,
+};
+use sp_inherents::{CreateInherentDataProviders, InherentDataProvider};
+use sp_runtime::{
+	generic::BlockId,
+	traits::{Block as BlockT, Header as HeaderT},
+	Justification,
+};
+
+/// A verifier that just checks the inherents.
+struct Verifier<Client, Block, IDP> {
+	client: Arc<Client>,
+	inherent_data_providers: IDP,
+	_marker: PhantomData<Block>,
+}
+
+#[async_trait::async_trait]
+impl<Client, Block, IDP> VerifierT<Block> for Verifier<Client, Block, IDP>
+where
+	Block: BlockT,
+	Client: ProvideRuntimeApi<Block> + Send + Sync,
+	<Client as ProvideRuntimeApi<Block>>::Api: BlockBuilderApi<Block>,
+	IDP: CreateInherentDataProviders<Block, ()> + Send + Sync,
+	IDP::InherentDataProviders: Send + Sync,
+{
+	async fn verify(
+		&mut self,
+		origin: BlockOrigin,
+		header: Block::Header,
+		justification: Option<Justification>,
+		mut body: Option<Vec<Block::Extrinsic>>,
+	) -> Result<
+		(
+			BlockImportParams<Block, ()>,
+			Option<Vec<(CacheKeyId, Vec<u8>)>>,
+		),
+		String,
+	> {
+		if let Some(inner_body) = body.take() {
+			let inherent_data_providers = self
+				.inherent_data_providers
+				.create_inherent_data_providers(*header.parent_hash(), ())
+				.await
+				.map_err(|e| e.to_string())?;
+
+			let inherent_data = inherent_data_providers
+				.create_inherent_data()
+				.map_err(|e| e.into_string())?;
+
+			let block = Block::new(header.clone(), inner_body);
+
+			let inherent_res = self
+				.client
+				.runtime_api()
+				.check_inherents(
+					&BlockId::Hash(*header.parent_hash()),
+					block.clone(),
+					inherent_data,
+				)
+				.map_err(|e| format!("{:?}", e))?;
+
+			if !inherent_res.ok() {
+				for (i, e) in inherent_res.into_errors() {
+					match inherent_data_providers.try_handle_error(&i, &e) {
+						Some(r) => r.await.map_err(|e| e.to_string())?,
+						None => todo!(),
+					}
+				}
+			}
+
+			let (_, inner_body) = block.deconstruct();
+			body = Some(inner_body);
+		}
+
+		let post_hash = Some(header.hash());
+		let mut block_import_params = BlockImportParams::new(origin, header);
+		block_import_params.body = body;
+		block_import_params.justification = justification;
+
+		// Best block is determined by the relay chain, or if we are doing the intial sync
+		// we import all blocks as new best.
+		block_import_params.fork_choice = Some(ForkChoiceStrategy::Custom(
+			origin == BlockOrigin::NetworkInitialSync,
+		));
+		block_import_params.post_hash = post_hash;
+
+		Ok((block_import_params, None))
+	}
+}
+
+/// Start an import queue for a Cumulus collator that does not uses any special authoring logic.
+pub fn import_queue<Client, Block: BlockT, I, IDP>(
+	client: Arc<Client>,
+	block_import: I,
+	inherent_data_providers: IDP,
+	spawner: &impl sp_core::traits::SpawnNamed,
+	registry: Option<&substrate_prometheus_endpoint::Registry>,
+) -> ClientResult<BasicQueue<Block, I::Transaction>>
+where
+	I: BlockImport<Block, Error = ConsensusError> + Send + Sync + 'static,
+	I::Transaction: Send,
+	Client: ProvideRuntimeApi<Block> + Send + Sync + 'static,
+	<Client as ProvideRuntimeApi<Block>>::Api: BlockBuilderApi<Block>,
+	IDP: CreateInherentDataProviders<Block, ()> + Send + Sync + 'static,
+	IDP::InherentDataProviders: Send + Sync,
+{
+	let verifier = Verifier {
+		client,
+		inherent_data_providers,
+		_marker: PhantomData,
+	};
+
+	Ok(BasicQueue::new(
+		verifier,
+		Box::new(block_import),
+		None,
+		spawner,
+		registry,
+	))
+}