asyncify the big collator future (#40)

* Rewrite collator future

* Add future to tests

cumulus/collator/src/lib.rs

@@ -41,9 +41,9 @@ use codec::{Decode, Encode};
 
 use log::{error, trace};
 
-use futures::{future, task::Spawn, Future, FutureExt, TryFutureExt};
+use futures::{task::Spawn, Future};
 
-use std::{fmt::Debug, marker::PhantomData, sync::Arc, time::Duration};
+use std::{fmt::Debug, marker::PhantomData, sync::Arc, time::Duration, pin::Pin};
 
 use parking_lot::Mutex;
 
@@ -105,34 +105,33 @@ where
 		+ Sync
 		+ 'static,
 {
-	type ProduceCandidate = Box<
-		dyn Future<Output = Result<(BlockData, parachain::HeadData, OutgoingMessages), InvalidHead>>
-			+ Send
-			+ Unpin,
-	>;
+	type ProduceCandidate = Pin<Box<
+		dyn Future<Output=Result<(BlockData, parachain::HeadData, OutgoingMessages), InvalidHead>>
+		+ Send,
+	>>;
 
-	fn produce_candidate<I: IntoIterator<Item = (ParaId, Message)>>(
+	fn produce_candidate<I: IntoIterator<Item=(ParaId, Message)>>(
 		&mut self,
 		_relay_chain_parent: PHash,
 		status: ParachainStatus,
 		_: I,
 	) -> Self::ProduceCandidate {
-		trace!(target: "cumulus-collator", "Producing candidate");
-
 		let factory = self.proposer_factory.clone();
 		let inherent_providers = self.inherent_data_providers.clone();
 		let block_import = self.block_import.clone();
 
-		let res = future::ready(
-			HeadData::<Block>::decode(&mut &status.head_data.0[..]).map_err(|e| {
+		Box::pin(async move {
+			trace!(target: "cumulus-collator", "Producing candidate");
+
+			let last_head = HeadData::<Block>::decode(&mut &status.head_data.0[..]).map_err(|e| {
 				error!(target: "cumulus-collator", "Could not decode the head data: {:?}", e);
 				InvalidHead
-			}),
-		)
-		.and_then(move |last_head| {
+			})?;
+
+
 			let parent_state_root = *last_head.header.state_root();
 
-			let proposer_inherent_data = factory
+			let mut proposer = factory
 				.lock()
 				.init(&last_head.header)
 				.map_err(|e| {
@@ -142,73 +141,60 @@ where
 						e,
 					);
 					InvalidHead
-				})
-				.and_then(|proposer| {
-					inherent_providers
-						.create_inherent_data()
-						.map_err(|e| {
-							error!(
-							target: "cumulus-collator",
-								"Failed to create inherent data: {:?}",
-								e,
-							);
-							InvalidHead
-						})
-						.map(move |inherent_data| (proposer, inherent_data))
-				});
+				})?;
 
-			future::ready(proposer_inherent_data).and_then(move |(mut proposer, inherent_data)| {
-				proposer
-					.propose(
-						inherent_data,
-						Default::default(),
-						//TODO: Fix this.
-						Duration::from_secs(6),
-						RecordProof::Yes,
-					)
-					.map_err(|e| {
-						error!(
-							target: "cumulus-collator",
-							"Proposing failed: {:?}",
-							e,
-						);
-						InvalidHead
-					})
-					.and_then(move |proposal| {
-						let Proposal {
-							block,
-							storage_changes,
-							proof,
-						} = proposal;
-						let res = match proof {
-							Some(proof) => {
-								let (header, extrinsics) = block.deconstruct();
+			let inherent_data = inherent_providers
+				.create_inherent_data()
+				.map_err(|e| {
+					error!(
+						target: "cumulus-collator",
+						"Failed to create inherent data: {:?}",
+						e,
+					);
+					InvalidHead
+				})?;
 
-								// Create the parachain block data for the validators.
-								Ok((
-									ParachainBlockData::<Block>::new(
-										header,
-										extrinsics,
-										proof.iter_nodes().collect(),
-										parent_state_root,
-									),
-									storage_changes,
-								))
-							}
-							None => {
-								error!(
-									target: "cumulus-collator",
-									"Proposer did not return the requested proof.",
-								);
-								Err(InvalidHead)
-							}
-						};
+			let Proposal {
+				block,
+				storage_changes,
+				proof,
+			} = proposer
+				.propose(
+					inherent_data,
+					Default::default(),
+					//TODO: Fix this.
+					Duration::from_secs(6),
+					RecordProof::Yes,
+				)
+				.await
+				.map_err(|e| {
+					error!(
+						target: "cumulus-collator",
+						"Proposing failed: {:?}",
+						e,
+					);
+					InvalidHead
+				})?;
+
+			let proof = proof
+				.ok_or_else(|| {
+					error!(
+						target: "cumulus-collator",
+						"Proposer did not return the requested proof.",
+					);
+					InvalidHead
+				})?;
+
+			let (header, extrinsics) = block.deconstruct();
+
+			// Create the parachain block data for the validators.
+			let b = ParachainBlockData::<Block>::new(
+				header,
+				extrinsics,
+				proof.iter_nodes().collect(),
+				parent_state_root,
+			);
 
-						future::ready(res)
-					})
-			})
-		})
-		.and_then(move |(b, storage_changes)| {
 			let block_import_params = BlockImportParams {
 				origin: BlockOrigin::Own,
 				header: b.header().clone(),
@@ -226,7 +212,7 @@ where
 				storage_changes: Some(storage_changes),
 			};
 
-			let res = if let Err(err) = block_import
+			if let Err(err) = block_import
 				.lock()
 				.import_block(block_import_params, Default::default())
 			{
@@ -236,14 +222,9 @@ where
 					b.header().parent_hash(),
 					err,
 				);
-				Err(InvalidHead)
-			} else {
-				Ok(b)
-			};
+				return Err(InvalidHead);
+			}
 
-			future::ready(res)
-		})
-		.map_ok(|b| {
 			let block_data = BlockData(b.encode());
 			let head_data = HeadData::<Block> {
 				header: b.into_header(),
@@ -252,18 +233,16 @@ where
 				outgoing_messages: Vec::new(),
 			};
 
-			(
+			let candidate = (
 				block_data,
 				parachain::HeadData(head_data.encode()),
 				messages,
-			)
-		})
-		.then(|r| {
-			trace!(target: "cumulus-collator", "Produced candidate: {:?}", r);
-			future::ready(r)
-		});
+			);
 
-		Box::new(res)
+			trace!(target: "cumulus-collator", "Produced candidate: {:?}", candidate);
+
+			Ok(candidate)
+		})
 	}
 }
 
@@ -398,7 +377,7 @@ mod tests {
 	};
 	use test_runtime::{Block, Header};
 
-	use futures::Stream;
+	use futures::{Stream, future};
 
 	#[derive(Debug)]
 	struct Error;