1 files changed, 84 insertions, 0 deletions
diff --git a/third_party/rust/hyper/src/service/util.rs b/third_party/rust/hyper/src/service/util.rs
new file mode 100644
index 0000000000..7cba1206f1
--- /dev/null
+++ b/third_party/rust/hyper/src/service/util.rs
@@ -0,0 +1,84 @@
+use std::error::Error as StdError;
+use std::fmt;
+use std::marker::PhantomData;
+
+use crate::body::HttpBody;
+use crate::common::{task, Future, Poll};
+use crate::{Request, Response};
+
+/// Create a `Service` from a function.
+///
+/// # Example
+///
+/// ```
+/// use hyper::{Body, Request, Response, Version};
+/// use hyper::service::service_fn;
+///
+/// let service = service_fn(|req: Request<Body>| async move {
+///     if req.version() == Version::HTTP_11 {
+///         Ok(Response::new(Body::from("Hello World")))
+///     } else {
+///         // Note: it's usually better to return a Response
+///         // with an appropriate StatusCode instead of an Err.
+///         Err("not HTTP/1.1, abort connection")
+///     }
+/// });
+/// ```
+pub fn service_fn<F, R, S>(f: F) -> ServiceFn<F, R>
+where
+    F: FnMut(Request<R>) -> S,
+    S: Future,
+{
+    ServiceFn {
+        f,
+        _req: PhantomData,
+    }
+}
+
+/// Service returned by [`service_fn`]
+pub struct ServiceFn<F, R> {
+    f: F,
+    _req: PhantomData<fn(R)>,
+}
+
+impl<F, ReqBody, Ret, ResBody, E> tower_service::Service<crate::Request<ReqBody>>
+    for ServiceFn<F, ReqBody>
+where
+    F: FnMut(Request<ReqBody>) -> Ret,
+    ReqBody: HttpBody,
+    Ret: Future<Output = Result<Response<ResBody>, E>>,
+    E: Into<Box<dyn StdError + Send + Sync>>,
+    ResBody: HttpBody,
+{
+    type Response = crate::Response<ResBody>;
+    type Error = E;
+    type Future = Ret;
+
+    fn poll_ready(&mut self, _cx: &mut task::Context<'_>) -> Poll<Result<(), Self::Error>> {
+        Poll::Ready(Ok(()))
+    }
+
+    fn call(&mut self, req: Request<ReqBody>) -> Self::Future {
+        (self.f)(req)
+    }
+}
+
+impl<F, R> fmt::Debug for ServiceFn<F, R> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("impl Service").finish()
+    }
+}
+
+impl<F, R> Clone for ServiceFn<F, R>
+where
+    F: Clone,
+{
+    fn clone(&self) -> Self {
+        ServiceFn {
+            f: self.f.clone(),
+            _req: PhantomData,
+        }
+    }
+}
+
+impl<F, R> Copy for ServiceFn<F, R> where F: Copy {}