Update tokio to 0.2 again and remove TaskExecutors (#786)

* upgrade tokio again

* Remove WrappedExecutor

* switch to spawn_blocking

polkadot/availability-store/Cargo.toml

@@ -12,7 +12,7 @@ parking_lot = "0.9.0"
 derive_more = "0.99"
 log = "0.4.8"
 futures = "0.3.1"
-tokio = { version = "0.2.4", features = ["rt-core"] }
+tokio = { version = "0.2.10", features = ["rt-core"] }
 exit-future = "0.2.0"
 codec = { package = "parity-scale-codec", version = "1.1.0", features = ["derive"] }
 sc-network = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }

polkadot/availability-store/src/lib.rs

@@ -58,9 +58,6 @@ use worker::{
 
 use store::{Store as InnerStore};
 
-/// Abstraction over an executor that lets you spawn tasks in the background.
-pub(crate) type TaskExecutor = Arc<dyn Spawn + Send + Sync>;
-
 const LOG_TARGET: &str = "availability";
 
 /// Configuration for the availability store.
@@ -197,7 +194,7 @@ impl Store {
 		&self,
 		wrapped_block_import: I,
 		client: Arc<P>,
-		thread_pool: TaskExecutor,
+		spawner: impl Spawn,
 		keystore: KeyStorePtr,
 	) -> ClientResult<AvailabilityBlockImport<I, P>>
 	where
@@ -213,7 +210,7 @@ impl Store {
 			self.inner.clone(),
 			client,
 			wrapped_block_import,
-			thread_pool,
+			spawner,
 			keystore,
 			to_worker,
 		);

polkadot/availability-store/src/worker.rs

@@ -37,12 +37,12 @@ use polkadot_primitives::parachain::{
 	CandidateReceipt, ParachainHost, ValidatorId,
 	ValidatorPair, AvailableMessages, BlockData, ErasureChunk,
 };
-use futures::{prelude::*, future::select, channel::{mpsc, oneshot}, task::SpawnExt};
+use futures::{prelude::*, future::select, channel::{mpsc, oneshot}, task::{Spawn, SpawnExt}};
 use keystore::KeyStorePtr;
 
 use tokio::runtime::{Handle, Runtime as LocalRuntime};
 
-use crate::{LOG_TARGET, Data, TaskExecutor, ProvideGossipMessages, erasure_coding_topic};
+use crate::{LOG_TARGET, Data, ProvideGossipMessages, erasure_coding_topic};
 use crate::store::Store;
 
 /// Errors that may occur.
@@ -747,7 +747,7 @@ impl<I, P> AvailabilityBlockImport<I, P> {
 		availability_store: Store,
 		client: Arc<P>,
 		block_import: I,
-		thread_pool: TaskExecutor,
+		spawner: impl Spawn,
 		keystore: KeyStorePtr,
 		to_worker: mpsc::UnboundedSender<WorkerMsg>,
 	) -> Self
@@ -771,7 +771,7 @@ impl<I, P> AvailabilityBlockImport<I, P> {
 			exit.clone()
 		).map(drop);
 
-		if let Err(_) = thread_pool.spawn(Box::new(prune_available)) {
+		if let Err(_) = spawner.spawn(prune_available) {
 			error!(target: LOG_TARGET, "Failed to spawn availability pruning task");
 			exit_signal = None;
 		}