testing clippy's disallowed-types

axum/src/box_clone_service.rs

@@ -0,0 +1,89 @@
+use futures_util::future::BoxFuture;
+use std::{
+    fmt,
+    task::{Context, Poll},
+};
+use tower::ServiceExt;
+use tower_layer::{layer_fn, LayerFn};
+use tower_service::Service;
+
+/// Like `tower::BoxCloneService` but `Sync`
+pub(crate) struct BoxCloneService<T, U, E>(
+    Box<
+        dyn CloneService<T, Response = U, Error = E, Future = BoxFuture<'static, Result<U, E>>>
+            + Send
+            + Sync,
+    >,
+);
+
+impl<T, U, E> BoxCloneService<T, U, E> {
+    pub(crate) fn new<S>(inner: S) -> Self
+    where
+        S: Service<T, Response = U, Error = E> + Clone + Send + Sync + 'static,
+        S::Future: Send + 'static,
+    {
+        let inner = inner.map_future(|f| Box::pin(f) as _);
+        BoxCloneService(Box::new(inner))
+    }
+
+    pub(crate) fn layer<S>() -> LayerFn<fn(S) -> Self>
+    where
+        S: Service<T, Response = U, Error = E> + Clone + Send + Sync + 'static,
+        S::Future: Send + 'static,
+    {
+        layer_fn(Self::new)
+    }
+}
+
+impl<T, U, E> Service<T> for BoxCloneService<T, U, E> {
+    type Response = U;
+    type Error = E;
+    type Future = BoxFuture<'static, Result<U, E>>;
+
+    #[inline]
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), E>> {
+        self.0.poll_ready(cx)
+    }
+
+    #[inline]
+    fn call(&mut self, request: T) -> Self::Future {
+        self.0.call(request)
+    }
+}
+
+impl<T, U, E> Clone for BoxCloneService<T, U, E> {
+    fn clone(&self) -> Self {
+        Self(self.0.clone_box())
+    }
+}
+
+trait CloneService<R>: Service<R> {
+    fn clone_box(
+        &self,
+    ) -> Box<
+        dyn CloneService<R, Response = Self::Response, Error = Self::Error, Future = Self::Future>
+            + Send
+            + Sync,
+    >;
+}
+
+impl<R, T> CloneService<R> for T
+where
+    T: Service<R> + Send + Sync + Clone + 'static,
+{
+    fn clone_box(
+        &self,
+    ) -> Box<
+        dyn CloneService<R, Response = T::Response, Error = T::Error, Future = T::Future>
+            + Send
+            + Sync,
+    > {
+        Box::new(self.clone())
+    }
+}
+
+impl<T, U, E> fmt::Debug for BoxCloneService<T, U, E> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BoxCloneService").finish()
+    }
+}

axum/src/lib.rs

@@ -421,6 +421,7 @@
 #[macro_use]
 pub(crate) mod macros;
 
+mod box_clone_service;
 mod boxed;
 mod extension;
 #[cfg(feature = "form")]

clippy.toml

@@ -0,0 +1,3 @@
+disallowed-types = [
+    { path = "tower::util::BoxCloneService", reason = "Use our internal BoxCloneService which is Sync" },
+]