Expect the poll_acquire error, not return (#362)

* Expect the poll_acquire error, not return

* Remove Error in tower-limit

tower-limit/src/concurrency/future.rs

@@ -1,6 +1,5 @@
 //! Future types
 //!
-use super::Error;
 use futures_core::ready;
 use pin_project::{pin_project, pinned_drop};
 use std::sync::Arc;
@@ -29,12 +28,11 @@ impl<T> ResponseFuture<T> {
 impl<F, T, E> Future for ResponseFuture<F>
 where
     F: Future<Output = Result<T, E>>,
-    E: Into<Error>,
 {
-    type Output = Result<T, Error>;
+    type Output = Result<T, E>;
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        Poll::Ready(ready!(self.project().inner.poll(cx)).map_err(Into::into))
+        Poll::Ready(ready!(self.project().inner.poll(cx)))
     }
 }
 

tower-limit/src/concurrency/mod.rs

@@ -5,5 +5,3 @@ mod layer;
 mod service;
 
 pub use self::{layer::ConcurrencyLimitLayer, service::ConcurrencyLimit};
-
-type Error = Box<dyn std::error::Error + Send + Sync>;

tower-limit/src/concurrency/service.rs

@@ -1,4 +1,4 @@
-use super::{future::ResponseFuture, Error};
+use super::future::ResponseFuture;
 
 use tower_service::Service;
 
@@ -52,16 +52,16 @@ impl<T> ConcurrencyLimit<T> {
 impl<S, Request> Service<Request> for ConcurrencyLimit<S>
 where
     S: Service<Request>,
-    S::Error: Into<Error>,
 {
     type Response = S::Response;
-    type Error = Error;
+    type Error = S::Error;
     type Future = ResponseFuture<S::Future>;
 
     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        ready!(self.limit.permit.poll_acquire(cx, &self.limit.semaphore))?;
+        ready!(self.limit.permit.poll_acquire(cx, &self.limit.semaphore))
+            .expect("poll_acquire after semaphore closed ");
 
-        Poll::Ready(ready!(self.inner.poll_ready(cx)).map_err(Into::into))
+        Poll::Ready(ready!(self.inner.poll_ready(cx)))
     }
 
     fn call(&mut self, request: Request) -> Self::Future {

tower-limit/src/rate/error.rs

@@ -1,3 +0,0 @@
-use std::error;
-
-pub(crate) type Error = Box<dyn error::Error + Send + Sync>;

tower-limit/src/rate/future.rs

@@ -1,36 +0,0 @@
-//! Future types
-
-use super::error::Error;
-use futures_core::ready;
-use pin_project::pin_project;
-use std::{
-    future::Future,
-    pin::Pin,
-    task::{Context, Poll},
-};
-
-/// Future for the `RateLimit` service.
-#[pin_project]
-#[derive(Debug)]
-pub struct ResponseFuture<T> {
-    #[pin]
-    inner: T,
-}
-
-impl<T> ResponseFuture<T> {
-    pub(crate) fn new(inner: T) -> ResponseFuture<T> {
-        ResponseFuture { inner }
-    }
-}
-
-impl<F, T, E> Future for ResponseFuture<F>
-where
-    F: Future<Output = Result<T, E>>,
-    Error: From<E>,
-{
-    type Output = Result<T, Error>;
-
-    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        Poll::Ready(Ok(ready!(self.project().inner.poll(cx))?))
-    }
-}

tower-limit/src/rate/mod.rs

@@ -1,7 +1,5 @@
 //! Limit the rate at which requests are processed.
 
-mod error;
-pub mod future;
 mod layer;
 mod rate;
 mod service;

tower-limit/src/rate/service.rs

@@ -1,4 +1,4 @@
-use super::{error::Error, future::ResponseFuture, Rate};
+use super::Rate;
 use futures_core::ready;
 use std::{
     future::Future,
@@ -60,17 +60,14 @@ impl<T> RateLimit<T> {
 impl<S, Request> Service<Request> for RateLimit<S>
 where
     S: Service<Request>,
-    Error: From<S::Error>,
 {
     type Response = S::Response;
-    type Error = Error;
-    type Future = ResponseFuture<S::Future>;
+    type Error = S::Error;
+    type Future = S::Future;
 
     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
         match self.state {
-            State::Ready { .. } => {
-                return Poll::Ready(ready!(self.inner.poll_ready(cx)).map_err(Error::from))
-            }
+            State::Ready { .. } => return Poll::Ready(ready!(self.inner.poll_ready(cx))),
             State::Limited(ref mut sleep) => {
                 ready!(Pin::new(sleep).poll(cx));
             }
@@ -81,7 +78,7 @@ where
             rem: self.rate.num(),
         };
 
-        Poll::Ready(ready!(self.inner.poll_ready(cx)).map_err(Error::from))
+        Poll::Ready(ready!(self.inner.poll_ready(cx)))
     }
 
     fn call(&mut self, request: Request) -> Self::Future {
@@ -107,8 +104,7 @@ where
                 }
 
                 // Call the inner future
-                let inner = self.inner.call(request);
-                ResponseFuture::new(inner)
+                self.inner.call(request)
             }
             State::Limited(..) => panic!("service not ready; poll_ready must be called first"),
         }