Remove `routing::Layered` (#383)

CHANGELOG.md

@@ -16,6 +16,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **breaking:** Added feature flags for HTTP1 and JSON. This enables removing a
   few dependencies if your app only uses HTTP2 or doesn't use JSON. Its only a
   breaking change if you depend on axum with `default_features = false`. ([#286])
+- **breaking:** Remove `routing::Layered` as it didn't actually do anything and
+  thus wasn't necessary
 
 [#339]: https://github.com/tokio-rs/axum/pull/339
 [#286]: https://github.com/tokio-rs/axum/pull/286

src/handler/mod.rs

@@ -241,7 +241,7 @@ pub trait Handler<B, T>: Clone + Send + Sized + 'static {
     /// This can be used to add additional processing to a request for a single
     /// handler.
     ///
-    /// Note this differs from [`routing::Layered`](crate::routing::Layered)
+    /// Note this differs from [`routing::Router::layer`](crate::routing::Router::layer)
     /// which adds a middleware to a group of routes.
     ///
     /// # Example

src/routing/mod.rs

@@ -260,13 +260,13 @@ impl<S> Router<S> {
         ResBody: http_body::Body<Data = Bytes> + Send + Sync + 'static,
         ResBody::Error: Into<BoxError>,
     {
-        self.map(|svc| {
+        self.layer(
             ServiceBuilder::new()
                 .layer_fn(BoxRoute)
                 .layer_fn(CloneBoxService::new)
                 .layer(MapResponseBodyLayer::new(box_body))
-                .service(svc)
-        })
+                .into_inner(),
+        )
     }
 
     /// Apply a [`tower::Layer`] to the router.
@@ -336,11 +336,11 @@ impl<S> Router<S> {
     /// # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
     /// # };
     /// ```
-    pub fn layer<L>(self, layer: L) -> Router<Layered<L::Service>>
+    pub fn layer<L>(self, layer: L) -> Router<L::Service>
     where
         L: Layer<S>,
     {
-        self.map(|svc| Layered::new(layer.layer(svc)))
+        self.map(|svc| layer.layer(svc))
     }
 
     /// Convert this router into a [`MakeService`], that is a [`Service`] who's
@@ -891,58 +891,6 @@ where
     }
 }
 
-/// A [`Service`] created from a router by applying a Tower middleware.
-///
-/// Created with [`Router::layer`]. See that method for more details.
-pub struct Layered<S> {
-    inner: S,
-}
-
-impl<S> Layered<S> {
-    fn new(inner: S) -> Self {
-        Self { inner }
-    }
-}
-
-impl<S> Clone for Layered<S>
-where
-    S: Clone,
-{
-    fn clone(&self) -> Self {
-        Self::new(self.inner.clone())
-    }
-}
-
-impl<S> fmt::Debug for Layered<S>
-where
-    S: fmt::Debug,
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("Layered")
-            .field("inner", &self.inner)
-            .finish()
-    }
-}
-
-impl<S, R> Service<R> for Layered<S>
-where
-    S: Service<R>,
-{
-    type Response = S::Response;
-    type Error = S::Error;
-    type Future = S::Future;
-
-    #[inline]
-    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        self.inner.poll_ready(cx)
-    }
-
-    #[inline]
-    fn call(&mut self, req: R) -> Self::Future {
-        self.inner.call(req)
-    }
-}
-
 /// A [`Service`] that has been nested inside a router at some path.
 ///
 /// Created with [`Router::nest`].
@@ -1144,9 +1092,6 @@ mod tests {
         assert_send::<BoxRoute<(), ()>>();
         assert_sync::<BoxRoute<(), ()>>();
 
-        assert_send::<Layered<()>>();
-        assert_sync::<Layered<()>>();
-
         assert_send::<Nested<(), ()>>();
         assert_sync::<Nested<(), ()>>();