style: Use tower-provided type-alias when useful

Cargo.toml

@@ -23,3 +23,4 @@ tower = { version = "0.4", features = ["full"] }
 [dev-dependencies]
 eyre = "0.6"
 tracing-subscriber = "0.3"
+console-subscriber = "0.1"

examples/simple.rs

@@ -14,15 +14,18 @@ async fn handle_req(req: Request) -> eyre::Result<Response> {
 
 #[tokio::main]
 async fn main() -> eyre::Result<()> {
-    tracing_subscriber::fmt()
+    setup_logging();
-        .with_max_level(tracing::Level::TRACE)
-        .init();
 
     let incoming = AddrIncoming::new("127.0.0.1:4567").await?;
 
     let make_service = tower::service_fn(|addr: &AddrStream| {
-        tracing::debug!("Accept: {} -> {}", addr.remote_addr, addr.local_addr);
+        tracing::debug!(remote_addr = %addr.remote_addr, local_addr = %addr.local_addr, "accept");
-        futures::future::ok::<_, std::convert::Infallible>(tower::service_fn(handle_req))
+
+        let service = tower::ServiceBuilder::new()
+            .buffer(16)
+            .service_fn(handle_req);
+
+        futures::future::ok::<_, std::convert::Infallible>(service)
     });
 
     let server = Server::new(incoming).serve(make_service);
@@ -30,3 +33,23 @@ async fn main() -> eyre::Result<()> {
 
     Ok(())
 }
+
+// Don't mind this, this is just for debugging.
+fn setup_logging() {
+    use tracing_subscriber::prelude::*;
+
+    tracing_subscriber::registry()
+        .with(console_subscriber::spawn())
+        .with(
+            tracing_subscriber::fmt::layer().with_filter(
+                tracing_subscriber::filter::Targets::new()
+                    .with_default(tracing::Level::DEBUG)
+                    .with_target("boitalettres", tracing::Level::TRACE)
+                    .with_target("simple", tracing::Level::TRACE)
+                    .with_target("tower", tracing::Level::TRACE)
+                    .with_target("tokio_tower", tracing::Level::TRACE)
+                    .with_target("mio", tracing::Level::TRACE),
+            ),
+        )
+        .init();
+}

src/server/mod.rs

@@ -20,7 +20,7 @@ pub enum Error<A> {
     #[error("Error occured when accepting new connections")]
     Accept(#[source] A),
     #[error("Error occured on service creation")]
-    MakeService(#[source] Box<dyn std::error::Error + Send + Sync + 'static>),
+    MakeService(#[source] tower::BoxError),
 }
 
 #[derive(Debug, Default, Clone)]
@@ -51,7 +51,7 @@ where
     I: Accept,
     I::Conn: AsyncRead + AsyncWrite + Unpin + Send + 'static,
     S: MakeServiceRef<I::Conn, Request, Response = Response>,
-    S::MakeError: Into<Box<dyn std::error::Error + Send + Sync + 'static>> + std::fmt::Display,
+    S::MakeError: Into<tower::BoxError> + std::fmt::Display,
     S::Error: std::fmt::Display,
     S::Future: Send + 'static,
     S::Service: Send + 'static,

src/server/pipeline.rs

@@ -8,7 +8,8 @@ use futures::stream::Stream;
 
 use crate::proto::{Request, Response};
 
-type Error = Box<dyn std::error::Error + Send + Sync + 'static>;
+type Error = tower::BoxError;
+type Result<T, E = Error> = std::result::Result<T, E>;
 
 #[pin_project::pin_project]
 pub struct Connection<C> {
@@ -32,7 +33,7 @@ impl<C> Stream for Connection<C>
 where
     C: AsyncRead + Unpin,
 {
-    type Item = Result<Request, Error>;
+    type Item = Result<Request>;
 
     fn poll_next(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Option<Self::Item>> {
         use imap_codec::parse::command::command as parse_command;
@@ -75,7 +76,7 @@ impl<C> Connection<C>
 where
     C: AsyncWrite,
 {
-    fn poll_flush_buffer(self: Pin<&mut Self>, cx: &mut task::Context) -> Poll<Result<(), Error>> {
+    fn poll_flush_buffer(self: Pin<&mut Self>, cx: &mut task::Context) -> Poll<Result<()>> {
         use bytes::Buf;
 
         let mut this = self.project();
@@ -89,7 +90,7 @@ where
         Poll::Ready(Ok(()))
     }
 
-    pub(crate) fn send(&mut self, item: Response) -> Result<(), Error> {
+    pub(crate) fn send(&mut self, item: Response) -> Result<()> {
         use bytes::BufMut;
         use imap_codec::codec::Encode;