make SelectChain async (#9128)

* make SelectChain async

* make JustificationImport async

substrate/client/consensus/babe/rpc/src/lib.rs

@@ -93,11 +93,14 @@ impl<B: BlockT, C, SC> BabeRpcHandler<B, C, SC> {
 }
 
 impl<B, C, SC> BabeApi for BabeRpcHandler<B, C, SC>
-	where
-		B: BlockT,
-		C: ProvideRuntimeApi<B> + HeaderBackend<B> + HeaderMetadata<B, Error=BlockChainError> + 'static,
-		C::Api: BabeRuntimeApi<B>,
-		SC: SelectChain<B> + Clone + 'static,
+where
+	B: BlockT,
+	C: ProvideRuntimeApi<B>
+		+ HeaderBackend<B>
+		+ HeaderMetadata<B, Error = BlockChainError>
+		+ 'static,
+	C::Api: BabeRuntimeApi<B>,
+	SC: SelectChain<B> + Clone + 'static,
 {
 	fn epoch_authorship(&self) -> FutureResult<HashMap<AuthorityId, EpochAuthorship>> {
 		if let Err(err) = self.deny_unsafe.check_if_safe() {
@@ -118,28 +121,33 @@ impl<B, C, SC> BabeApi for BabeRpcHandler<B, C, SC>
 			self.select_chain.clone(),
 		);
 		let future = async move {
-			let header = select_chain.best_chain().map_err(Error::Consensus)?;
-			let epoch_start = client.runtime_api()
+			let header = select_chain.best_chain().map_err(Error::Consensus).await?;
+			let epoch_start = client
+				.runtime_api()
 				.current_epoch_start(&BlockId::Hash(header.hash()))
-				.map_err(|err| {
-					Error::StringError(format!("{:?}", err))
-				})?;
+				.map_err(|err| Error::StringError(format!("{:?}", err)))?;
 			let epoch = epoch_data(
 				&shared_epoch,
 				&client,
 				&babe_config,
 				*epoch_start,
 				&select_chain,
-			)?;
+			)
+			.await?;
 			let (epoch_start, epoch_end) = (epoch.start_slot(), epoch.end_slot());
 
 			let mut claims: HashMap<AuthorityId, EpochAuthorship> = HashMap::new();
 
 			let keys = {
-				epoch.authorities.iter()
+				epoch
+					.authorities
+					.iter()
 					.enumerate()
 					.filter_map(|(i, a)| {
-						if SyncCryptoStore::has_keys(&*keystore, &[(a.0.to_raw_vec(), AuthorityId::ID)]) {
+						if SyncCryptoStore::has_keys(
+							&*keystore,
+							&[(a.0.to_raw_vec(), AuthorityId::ID)],
+						) {
 							Some((a.0.clone(), i))
 						} else {
 							None
@@ -167,7 +175,8 @@ impl<B, C, SC> BabeApi for BabeRpcHandler<B, C, SC>
 			}
 
 			Ok(claims)
-		}.boxed();
+		}
+		.boxed();
 
 		Box::new(future.compat())
 	}
@@ -203,20 +212,20 @@ impl From<Error> for jsonrpc_core::Error {
 	}
 }
 
-/// fetches the epoch data for a given slot.
-fn epoch_data<B, C, SC>(
+/// Fetches the epoch data for a given slot.
+async fn epoch_data<B, C, SC>(
 	epoch_changes: &SharedEpochChanges<B, Epoch>,
 	client: &Arc<C>,
 	babe_config: &Config,
 	slot: u64,
 	select_chain: &SC,
 ) -> Result<Epoch, Error>
-	where
-		B: BlockT,
-		C: HeaderBackend<B> + HeaderMetadata<B, Error=BlockChainError> + 'static,
-		SC: SelectChain<B>,
+where
+	B: BlockT,
+	C: HeaderBackend<B> + HeaderMetadata<B, Error = BlockChainError> + 'static,
+	SC: SelectChain<B>,
 {
-	let parent = select_chain.best_chain()?;
+	let parent = select_chain.best_chain().await?;
 	epoch_changes.shared_data().epoch_data_for_child_of(
 		descendent_query(&**client),
 		&parent.hash(),

substrate/client/consensus/babe/src/lib.rs

@@ -989,7 +989,7 @@ where
 		Ok(())
 	}
 
-	fn check_and_report_equivocation(
+	async fn check_and_report_equivocation(
 		&self,
 		slot_now: Slot,
 		slot: Slot,
@@ -1024,6 +1024,7 @@ where
 		let best_id = self
 			.select_chain
 			.best_chain()
+			.await
 			.map(|h| BlockId::Hash(h.hash()))
 			.map_err(|e| Error::Client(e.into()))?;
 
@@ -1070,13 +1071,26 @@ where
 	}
 }
 
+type BlockVerificationResult<Block> = Result<
+	(
+		BlockImportParams<Block, ()>,
+		Option<Vec<(CacheKeyId, Vec<u8>)>>,
+	),
+	String,
+>;
+
 #[async_trait::async_trait]
 impl<Block, Client, SelectChain, CAW, CIDP> Verifier<Block>
 	for BabeVerifier<Block, Client, SelectChain, CAW, CIDP>
 where
 	Block: BlockT,
-	Client: HeaderMetadata<Block, Error = sp_blockchain::Error> + HeaderBackend<Block> + ProvideRuntimeApi<Block>
-		+ Send + Sync + AuxStore + ProvideCache<Block>,
+	Client: HeaderMetadata<Block, Error = sp_blockchain::Error>
+		+ HeaderBackend<Block>
+		+ ProvideRuntimeApi<Block>
+		+ Send
+		+ Sync
+		+ AuxStore
+		+ ProvideCache<Block>,
 	Client::Api: BlockBuilderApi<Block> + BabeApi<Block>,
 	SelectChain: sp_consensus::SelectChain<Block>,
 	CAW: CanAuthorWith<Block> + Send + Sync,
@@ -1089,7 +1103,7 @@ where
 		header: Block::Header,
 		justifications: Option<Justifications>,
 		mut body: Option<Vec<Block::Extrinsic>>,
-	) -> Result<(BlockImportParams<Block, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
+	) -> BlockVerificationResult<Block> {
 		trace!(
 			target: "babe",
 			"Verifying origin: {:?} header: {:?} justification(s): {:?} body: {:?}",
@@ -1158,7 +1172,7 @@ where
 					&header,
 					&verified_info.author,
 					&origin,
-				) {
+				).await {
 					warn!(target: "babe", "Error checking/reporting BABE equivocation: {:?}", err);
 				}
 

substrate/client/consensus/common/Cargo.toml

@@ -13,6 +13,7 @@ readme = "README.md"
 targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
+async-trait = "0.1"
 sc-client-api = { version = "3.0.0", path = "../../api" }
 sp-blockchain = { version = "3.0.0", path = "../../../primitives/blockchain" }
 sp-runtime = { version = "3.0.0", path = "../../../primitives/runtime" }

substrate/client/consensus/common/src/longest_chain.rs

@@ -46,15 +46,15 @@ impl<B, Block> Clone for LongestChain<B, Block> {
 }
 
 impl<B, Block> LongestChain<B, Block>
-	where
-		B: backend::Backend<Block>,
-		Block: BlockT,
+where
+	B: backend::Backend<Block>,
+	Block: BlockT,
 {
 	/// Instantiate a new LongestChain for Backend B
 	pub fn new(backend: Arc<B>) -> Self {
 		LongestChain {
 			backend,
-			_phantom: Default::default()
+			_phantom: Default::default(),
 		}
 	}
 
@@ -75,30 +75,30 @@ impl<B, Block> LongestChain<B, Block>
 	}
 }
 
+#[async_trait::async_trait]
 impl<B, Block> SelectChain<Block> for LongestChain<B, Block>
-	where
-		B: backend::Backend<Block>,
-		Block: BlockT,
+where
+	B: backend::Backend<Block>,
+	Block: BlockT,
 {
-
-	fn leaves(&self) -> Result<Vec<<Block as BlockT>::Hash>, ConsensusError> {
-		LongestChain::leaves(self)
-			.map_err(|e| ConsensusError::ChainLookup(e.to_string()).into())
+	async fn leaves(&self) -> Result<Vec<<Block as BlockT>::Hash>, ConsensusError> {
+		LongestChain::leaves(self).map_err(|e| ConsensusError::ChainLookup(e.to_string()).into())
 	}
 
-	fn best_chain(&self) -> Result<<Block as BlockT>::Header, ConsensusError>
-	{
+	async fn best_chain(&self) -> Result<<Block as BlockT>::Header, ConsensusError> {
 		LongestChain::best_block_header(&self)
 			.map_err(|e| ConsensusError::ChainLookup(e.to_string()).into())
 	}
 
-	fn finality_target(
+	async fn finality_target(
 		&self,
 		target_hash: Block::Hash,
-		maybe_max_number: Option<NumberFor<Block>>
+		maybe_max_number: Option<NumberFor<Block>>,
 	) -> Result<Option<Block::Hash>, ConsensusError> {
 		let import_lock = self.backend.get_import_lock();
-		self.backend.blockchain().best_containing(target_hash, maybe_max_number, import_lock)
+		self.backend
+			.blockchain()
+			.best_containing(target_hash, maybe_max_number, import_lock)
 			.map_err(|e| ConsensusError::ChainLookup(e.to_string()).into())
 	}
 }

substrate/client/consensus/manual-seal/src/seal_block.rs

@@ -80,45 +80,47 @@ pub async fn seal_block<B, BI, SC, C, E, P, CIDP>(
 		create_inherent_data_providers,
 		consensus_data_provider: digest_provider,
 		mut sender,
-	}: SealBlockParams<'_, B, BI, SC, C, E, P, CIDP>
-)
-	where
-		B: BlockT,
-		BI: BlockImport<B, Error = sp_consensus::Error, Transaction = sp_api::TransactionFor<C, B>>
-			+ Send + Sync + 'static,
-		C: HeaderBackend<B> + ProvideRuntimeApi<B>,
-		E: Environment<B>,
-		E::Proposer: Proposer<B, Transaction = TransactionFor<C, B>>,
-		P: txpool::ChainApi<Block=B>,
-		SC: SelectChain<B>,
-		TransactionFor<C, B>: 'static,
-		CIDP: CreateInherentDataProviders<B, ()>,
+	}: SealBlockParams<'_, B, BI, SC, C, E, P, CIDP>,
+) where
+	B: BlockT,
+	BI: BlockImport<B, Error = sp_consensus::Error, Transaction = sp_api::TransactionFor<C, B>>
+		+ Send
+		+ Sync
+		+ 'static,
+	C: HeaderBackend<B> + ProvideRuntimeApi<B>,
+	E: Environment<B>,
+	E::Proposer: Proposer<B, Transaction = TransactionFor<C, B>>,
+	P: txpool::ChainApi<Block = B>,
+	SC: SelectChain<B>,
+	TransactionFor<C, B>: 'static,
+	CIDP: CreateInherentDataProviders<B, ()>,
 {
 	let future = async {
 		if pool.validated_pool().status().ready == 0 && !create_empty {
-			return Err(Error::EmptyTransactionPool)
+			return Err(Error::EmptyTransactionPool);
 		}
 
 		// get the header to build this new block on.
 		// use the parent_hash supplied via `EngineCommand`
 		// or fetch the best_block.
 		let parent = match parent_hash {
-			Some(hash) => {
-				client.header(BlockId::Hash(hash))?.ok_or_else(|| Error::BlockNotFound(format!("{}", hash)))?
-			}
-			None => select_chain.best_chain()?
+			Some(hash) => client
+				.header(BlockId::Hash(hash))?
+				.ok_or_else(|| Error::BlockNotFound(format!("{}", hash)))?,
+			None => select_chain.best_chain().await?,
 		};
 
-		let inherent_data_providers =
-			create_inherent_data_providers
-				.create_inherent_data_providers(parent.hash(), ())
-				.await
-				.map_err(|e| Error::Other(e))?;
+		let inherent_data_providers = create_inherent_data_providers
+			.create_inherent_data_providers(parent.hash(), ())
+			.await
+			.map_err(|e| Error::Other(e))?;
 
 		let inherent_data = inherent_data_providers.create_inherent_data()?;
 
-		let proposer = env.init(&parent)
-			.map_err(|err| Error::StringError(format!("{:?}", err))).await?;
+		let proposer = env
+			.init(&parent)
+			.map_err(|err| Error::StringError(format!("{:?}", err)))
+			.await?;
 		let inherents_len = inherent_data.len();
 
 		let digest = if let Some(digest_provider) = digest_provider {

substrate/client/consensus/pow/src/lib.rs

@@ -341,7 +341,10 @@ where
 		mut block: BlockImportParams<B, Self::Transaction>,
 		new_cache: HashMap<CacheKeyId, Vec<u8>>,
 	) -> Result<ImportResult, Self::Error> {
-		let best_header = self.select_chain.best_chain()
+		let best_header = self
+			.select_chain
+			.best_chain()
+			.await
 			.map_err(|e| format!("Fetch best chain failed via select chain: {:?}", e))?;
 		let best_hash = best_header.hash();
 
@@ -543,7 +546,8 @@ pub fn start_mining_worker<Block, C, S, Algorithm, E, SO, L, CIDP, CAW>(
 ) -> (
 	Arc<Mutex<MiningWorker<Block, Algorithm, C, L, <E::Proposer as Proposer<Block>>::Proof>>>,
 	impl Future<Output = ()>,
-) where
+)
+where
 	Block: BlockT,
 	C: ProvideRuntimeApi<Block> + BlockchainEvents<Block> + 'static,
 	S: SelectChain<Block> + 'static,
@@ -578,7 +582,7 @@ pub fn start_mining_worker<Block, C, S, Algorithm, E, SO, L, CIDP, CAW>(
 				return;
 			}
 
-			let best_header = match select_chain.best_chain() {
+			let best_header = match select_chain.best_chain().await {
 				Ok(x) => x,
 				Err(err) => {
 					warn!(
@@ -588,7 +592,7 @@ pub fn start_mining_worker<Block, C, S, Algorithm, E, SO, L, CIDP, CAW>(
 						err
 					);
 					return;
-				},
+				}
 			};
 			let best_hash = best_header.hash();
 

substrate/client/consensus/slots/src/slots.rs

@@ -151,7 +151,7 @@ where
 
 			let ends_at = Instant::now() + ends_in;
 
-			let chain_head = match self.client.best_chain() {
+			let chain_head = match self.client.best_chain().await {
 				Ok(x) => x,
 				Err(e) => {
 					log::warn!(