From 54bc91581f4c26b1e8f836f3d66bca74c9f14569 Mon Sep 17 00:00:00 2001
From: Thomas Eizinger <thomas@eizinger.io>
Date: Wed, 3 Mar 2021 13:36:37 +1100
Subject: [PATCH] Don't unnecessarily create async blocks

If our expression directly evaluates to a future, we don't need to
create an async block.

This requires us to have `EventLoopRun::run` consume the instance
instead of just taking a mutable reference (otherwise we run into
lifetime issues). However, that is better anyway because `run` is
an endless loop so you never get to use the handle afterwards
anyway.
---
 swap/src/bin/asb.rs                   |  2 +-
 swap/src/bin/swap_cli.rs              |  4 ++--
 swap/src/protocol/alice/event_loop.rs |  2 +-
 swap/tests/testutils/mod.rs           | 10 ++++------
 4 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/swap/src/bin/asb.rs b/swap/src/bin/asb.rs
index 41b6b234..488aade3 100644
--- a/swap/src/bin/asb.rs
+++ b/swap/src/bin/asb.rs
@@ -100,7 +100,7 @@ async fn main() -> Result<()> {
 
             let rate_service = kraken::RateService::new().await?;
 
-            let (mut event_loop, _) = EventLoop::new(
+            let (event_loop, _) = EventLoop::new(
                 config.network.listen,
                 seed,
                 execution_params,
diff --git a/swap/src/bin/swap_cli.rs b/swap/src/bin/swap_cli.rs
index 9fded67e..0e75c214 100644
--- a/swap/src/bin/swap_cli.rs
+++ b/swap/src/bin/swap_cli.rs
@@ -149,7 +149,7 @@ async fn main() -> Result<()> {
             );
             let (swap, event_loop) = bob_factory.with_init_params(send_bitcoin).build().await?;
 
-            let handle = tokio::spawn(async move { event_loop.run().await });
+            let handle = tokio::spawn(event_loop.run());
             let swap = bob::run(swap);
             tokio::select! {
                 event_loop_result = handle => {
@@ -193,7 +193,7 @@ async fn main() -> Result<()> {
                 execution_params,
             );
             let (swap, event_loop) = bob_factory.build().await?;
-            let handle = tokio::spawn(async move { event_loop.run().await });
+            let handle = tokio::spawn(event_loop.run());
             let swap = bob::run(swap);
             tokio::select! {
                 event_loop_result = handle => {
diff --git a/swap/src/protocol/alice/event_loop.rs b/swap/src/protocol/alice/event_loop.rs
index 3716d2cf..a188930f 100644
--- a/swap/src/protocol/alice/event_loop.rs
+++ b/swap/src/protocol/alice/event_loop.rs
@@ -158,7 +158,7 @@ where
         self.peer_id
     }
 
-    pub async fn run(&mut self) {
+    pub async fn run(mut self) {
         loop {
             tokio::select! {
                 swarm_event = self.swarm.next().fuse() => {
diff --git a/swap/tests/testutils/mod.rs b/swap/tests/testutils/mod.rs
index b6494605..844c127e 100644
--- a/swap/tests/testutils/mod.rs
+++ b/swap/tests/testutils/mod.rs
@@ -103,7 +103,7 @@ impl TestContext {
             .await
             .unwrap();
 
-        let join_handle = tokio::spawn(async move { event_loop.run().await });
+        let join_handle = tokio::spawn(event_loop.run());
 
         (swap, BobEventLoopJoinHandle(join_handle))
     }
@@ -116,7 +116,7 @@ impl TestContext {
 
         let (swap, event_loop) = self.bob_params.builder().build().await.unwrap();
 
-        let join_handle = tokio::spawn(async move { event_loop.run().await });
+        let join_handle = tokio::spawn(event_loop.run());
 
         (swap, BobEventLoopJoinHandle(join_handle))
     }
@@ -376,7 +376,7 @@ where
     )
     .await;
 
-    let (mut alice_event_loop, alice_swap_handle) = alice::EventLoop::new(
+    let (alice_event_loop, alice_swap_handle) = alice::EventLoop::new(
         alice_listen_address.clone(),
         alice_seed,
         execution_params,
@@ -390,9 +390,7 @@ where
 
     let alice_peer_id = alice_event_loop.peer_id();
 
-    tokio::spawn(async move {
-        alice_event_loop.run().await;
-    });
+    tokio::spawn(alice_event_loop.run());
 
     let bob_params = BobParams {
         seed: Seed::random().unwrap(),