From af636a85be5d166e7d153ff7ab04b1ac0ae6286c Mon Sep 17 00:00:00 2001
From: tottoto <tottotodev@gmail.com>
Date: Sat, 28 Sep 2024 08:15:51 +0900
Subject: [PATCH] feat(web): Add CorsGrpcWebResponseFuture to make tower-http
 internal dependency

---
 tonic-web/Cargo.toml |  1 -
 tonic-web/src/lib.rs | 42 ++++++++++++++++++++++++++++++++++--------
 2 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/tonic-web/Cargo.toml b/tonic-web/Cargo.toml
index 85e5ccb9c..c8cf054d4 100644
--- a/tonic-web/Cargo.toml
+++ b/tonic-web/Cargo.toml
@@ -43,7 +43,6 @@ allowed_external_types = [
   # not major released
   "futures_core::stream::Stream",
   "http_body_util::combinators::box_body::UnsyncBoxBody",
-  "tower_http::cors::Cors",
   "tower_layer::Layer",
   "tower_service::Service",
 ]
diff --git a/tonic-web/src/lib.rs b/tonic-web/src/lib.rs
index d768a7005..2648e06a5 100644
--- a/tonic-web/src/lib.rs
+++ b/tonic-web/src/lib.rs
@@ -108,7 +108,14 @@ mod layer;
 mod service;
 
 use http::header::HeaderName;
-use std::time::Duration;
+use pin_project::pin_project;
+use std::{
+    fmt,
+    future::Future,
+    pin::Pin,
+    task::{Context, Poll},
+    time::Duration,
+};
 use tonic::{body::BoxBody, server::NamedService, Status};
 use tower_http::cors::{AllowOrigin, CorsLayer};
 use tower_layer::Layer;
@@ -155,18 +162,37 @@ where
 {
     type Response = S::Response;
     type Error = S::Error;
-    type Future =
-        <tower_http::cors::Cors<GrpcWebService<S>> as Service<http::Request<BoxBody>>>::Future;
+    type Future = CorsGrpcWebResponseFuture<S::Future>;
 
-    fn poll_ready(
-        &mut self,
-        cx: &mut std::task::Context<'_>,
-    ) -> std::task::Poll<Result<(), Self::Error>> {
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
         self.0.poll_ready(cx)
     }
 
     fn call(&mut self, req: http::Request<BoxBody>) -> Self::Future {
-        self.0.call(req)
+        CorsGrpcWebResponseFuture(self.0.call(req))
+    }
+}
+
+/// Response Future for the [`CorsGrpcWeb`].
+#[pin_project]
+pub struct CorsGrpcWebResponseFuture<F>(
+    #[pin] tower_http::cors::ResponseFuture<service::ResponseFuture<F>>,
+);
+
+impl<F, E> Future for CorsGrpcWebResponseFuture<F>
+where
+    F: Future<Output = Result<http::Response<BoxBody>, E>>,
+{
+    type Output = Result<http::Response<BoxBody>, E>;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        self.project().0.poll(cx)
+    }
+}
+
+impl<F> fmt::Debug for CorsGrpcWebResponseFuture<F> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("CorsGrpcWebResponseFuture").finish()
     }
 }