From 7b0590e4308c3072b96a82ad47504af0ba326e0c Mon Sep 17 00:00:00 2001
From: Cecile Tonglet <cecile@parity.io>
Date: Thu, 18 Jun 2020 12:08:26 +0200
Subject: [PATCH] impl From<Fn> for TaskExecutor

---
 client/cli/src/runner.rs       | 28 ++++++++++++----------------
 client/service/src/config.rs   | 21 ++++++---------------
 client/service/test/src/lib.rs | 10 ++++------
 utils/browser/src/lib.rs       |  4 ++--
 4 files changed, 24 insertions(+), 39 deletions(-)

diff --git a/client/cli/src/runner.rs b/client/cli/src/runner.rs
index 7aa5a99a7bb42..2aa649ff9746a 100644
--- a/client/cli/src/runner.rs
+++ b/client/cli/src/runner.rs
@@ -25,9 +25,7 @@ use futures::pin_mut;
 use futures::select;
 use futures::{future, future::FutureExt, Future};
 use log::info;
-use sc_service::{
-	AbstractService, Configuration, Role, ServiceBuilderCommand, TaskType, config::TaskExecutor,
-};
+use sc_service::{AbstractService, Configuration, Role, ServiceBuilderCommand, TaskType};
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT};
 use sp_utils::metrics::{TOKIO_THREADS_ALIVE, TOKIO_THREADS_TOTAL};
 use sp_version::RuntimeVersion;
@@ -121,23 +119,21 @@ impl<C: SubstrateCli> Runner<C> {
 		let tokio_runtime = build_runtime()?;
 		let runtime_handle = tokio_runtime.handle().clone();
 
-		let task_executor = TaskExecutor::from_fn(
-			move |fut, task_type| {
-				match task_type {
-					TaskType::Async => { runtime_handle.spawn(fut); }
-					TaskType::Blocking => {
-						runtime_handle.spawn( async move {
-							// `spawn_blocking` is looking for the current runtime, and as such has to be called
-							// from within `spawn`.
-							tokio::task::spawn_blocking(move || futures::executor::block_on(fut))
-						});
-					}
+		let task_executor = move |fut, task_type| {
+			match task_type {
+				TaskType::Async => { runtime_handle.spawn(fut); }
+				TaskType::Blocking => {
+					runtime_handle.spawn( async move {
+						// `spawn_blocking` is looking for the current runtime, and as such has to
+						// be called from within `spawn`.
+						tokio::task::spawn_blocking(move || futures::executor::block_on(fut))
+					});
 				}
 			}
-		);
+		};
 
 		Ok(Runner {
-			config: command.create_configuration(cli, task_executor)?,
+			config: command.create_configuration(cli, task_executor.into())?,
 			tokio_runtime,
 			phantom: PhantomData,
 		})
diff --git a/client/service/src/config.rs b/client/service/src/config.rs
index 0eb62c55a3e74..2f54f84f717d4 100644
--- a/client/service/src/config.rs
+++ b/client/service/src/config.rs
@@ -266,14 +266,14 @@ impl std::fmt::Debug for TaskExecutor {
 	}
 }
 
-/*
-impl std::convert::From<TaskExecutorInner> for TaskExecutor {
-	fn from(x: TaskExecutorInner)
-	-> Self {
-		Self(x)
+impl<F> std::convert::From<F> for TaskExecutor
+where
+	F: Fn(Pin<Box<dyn Future<Output = ()> + Send>>, TaskType) + Send + Sync + 'static,
+{
+	fn from(x: F) -> Self {
+		Self(Arc::new(x))
 	}
 }
-*/
 
 impl std::ops::Deref for TaskExecutor {
 	type Target = TaskExecutorInner;
@@ -282,12 +282,3 @@ impl std::ops::Deref for TaskExecutor {
 		&self.0
 	}
 }
-
-impl TaskExecutor {
-	/// Create a `TaskExecutor` from a function
-	pub fn from_fn(
-		f: impl Fn(Pin<Box<dyn Future<Output = ()> + Send>>, TaskType) + Send + Sync + 'static,
-	) -> Self {
-		Self(Arc::new(f))
-	}
-}
diff --git a/client/service/test/src/lib.rs b/client/service/test/src/lib.rs
index 0f1dd0f2d64de..932de27c0ed15 100644
--- a/client/service/test/src/lib.rs
+++ b/client/service/test/src/lib.rs
@@ -255,13 +255,11 @@ impl<G, E, F, L, U> TestNet<G, E, F, L, U> where
 		authorities: impl Iterator<Item = (String, impl FnOnce(Configuration) -> Result<(F, U), Error>)>
 	) {
 		let executor = self.runtime.executor();
-		let task_executor = {
+		let task_executor: TaskExecutor = {
 			let executor = executor.clone();
-			TaskExecutor::from_fn(
-				move |fut: Pin<Box<dyn futures::Future<Output = ()> + Send>>, _| {
-					executor.spawn(fut.unit_error().compat());
-				},
-			)
+			(move |fut: Pin<Box<dyn futures::Future<Output = ()> + Send>>, _| {
+				executor.spawn(fut.unit_error().compat());
+			}).into()
 		};
 
 		for (key, authority) in authorities {
diff --git a/utils/browser/src/lib.rs b/utils/browser/src/lib.rs
index 8776033acacd9..3e66321a22c76 100644
--- a/utils/browser/src/lib.rs
+++ b/utils/browser/src/lib.rs
@@ -20,7 +20,7 @@ use log::{debug, info};
 use sc_network::config::TransportConfig;
 use sc_service::{
 	AbstractService, RpcSession, Role, Configuration,
-	config::{DatabaseConfig, KeystoreConfig, NetworkConfiguration, TaskExecutor},
+	config::{DatabaseConfig, KeystoreConfig, NetworkConfiguration},
 	GenericChainSpec, RuntimeGenesis
 };
 use wasm_bindgen::prelude::*;
@@ -63,7 +63,7 @@ where
 		network,
 		telemetry_endpoints: chain_spec.telemetry_endpoints().clone(),
 		chain_spec: Box::new(chain_spec),
-		task_executor: TaskExecutor::from_fn(|fut, _| wasm_bindgen_futures::spawn_local(fut)),
+		task_executor: (|fut, _| wasm_bindgen_futures::spawn_local(fut)).into(),
 		telemetry_external_transport: Some(transport),
 		role: Role::Light,
 		database: {