From 8d7d9451d0bfdb2a0df7344b7dc37365ba4195fe Mon Sep 17 00:00:00 2001
From: Benjamin Saunders <ben.e.saunders@gmail.com>
Date: Sun, 19 Dec 2021 14:07:38 -0800
Subject: [PATCH] Make futures-util dependency optional

---
 quinn/Cargo.toml         |  5 +++--
 quinn/src/recv_stream.rs |  4 ++--
 quinn/src/send_stream.rs | 12 ++++++------
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/quinn/Cargo.toml b/quinn/Cargo.toml
index b799e9aa1..5702d11e5 100644
--- a/quinn/Cargo.toml
+++ b/quinn/Cargo.toml
@@ -14,7 +14,7 @@ edition = "2018"
 all-features = true
 
 [features]
-default = ["native-certs", "tls-rustls", "ring"]
+default = ["native-certs", "tls-rustls", "ring", "futures-util"]
 # Records how long locks are held, and warns if they are held >= 1ms
 lock_tracking = []
 # Provides `ClientConfig::with_native_roots()` convenience method
@@ -29,7 +29,8 @@ maintenance = { status = "experimental" }
 
 [dependencies]
 bytes = "1"
-futures-util = { version = "0.3.11", default-features = false, features = ["io"] }
+# Enables futures_util::io::{AsyncRead, AsyncWrite} support for streams
+futures-util = { version = "0.3.11", default-features = false, features = ["io"], optional = true }
 futures-core = "0.3.19"
 futures-channel = "0.3.11"
 rustc-hash = "1.1"
diff --git a/quinn/src/recv_stream.rs b/quinn/src/recv_stream.rs
index 52dff3826..f99b5a22d 100644
--- a/quinn/src/recv_stream.rs
+++ b/quinn/src/recv_stream.rs
@@ -6,7 +6,6 @@ use std::{
 };
 
 use bytes::Bytes;
-use futures_util::io::AsyncRead;
 use proto::{Chunk, Chunks, ConnectionError, ReadableError, StreamId};
 use thiserror::Error;
 use tokio::io::ReadBuf;
@@ -355,7 +354,8 @@ pub enum ReadToEndError {
     TooLong,
 }
 
-impl AsyncRead for RecvStream {
+#[cfg(feature = "futures-util")]
+impl futures_util::io::AsyncRead for RecvStream {
     fn poll_read(
         self: Pin<&mut Self>,
         cx: &mut Context,
diff --git a/quinn/src/send_stream.rs b/quinn/src/send_stream.rs
index c0905f4ae..b979ef559 100644
--- a/quinn/src/send_stream.rs
+++ b/quinn/src/send_stream.rs
@@ -7,7 +7,6 @@ use std::{
 
 use bytes::Bytes;
 use futures_channel::oneshot;
-use futures_util::io::AsyncWrite;
 use proto::{ConnectionError, FinishError, StreamId, Written};
 use thiserror::Error;
 
@@ -220,9 +219,10 @@ impl SendStream {
     }
 }
 
-impl AsyncWrite for SendStream {
+#[cfg(feature = "futures-util")]
+impl futures_util::io::AsyncWrite for SendStream {
     fn poll_write(self: Pin<&mut Self>, cx: &mut Context, buf: &[u8]) -> Poll<io::Result<usize>> {
-        SendStream::execute_poll(self.get_mut(), cx, |stream| stream.write(buf)).map_err(Into::into)
+        tokio::io::AsyncWrite::poll_write(self, cx, buf)
     }
 
     fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context) -> Poll<io::Result<()>> {
@@ -230,7 +230,7 @@ impl AsyncWrite for SendStream {
     }
 
     fn poll_close(self: Pin<&mut Self>, cx: &mut Context) -> Poll<io::Result<()>> {
-        self.get_mut().poll_finish(cx).map_err(Into::into)
+        tokio::io::AsyncWrite::poll_shutdown(self, cx)
     }
 }
 
@@ -240,7 +240,7 @@ impl tokio::io::AsyncWrite for SendStream {
         cx: &mut Context<'_>,
         buf: &[u8],
     ) -> Poll<io::Result<usize>> {
-        AsyncWrite::poll_write(self, cx, buf)
+        SendStream::execute_poll(self.get_mut(), cx, |stream| stream.write(buf)).map_err(Into::into)
     }
 
     fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context) -> Poll<io::Result<()>> {
@@ -248,7 +248,7 @@ impl tokio::io::AsyncWrite for SendStream {
     }
 
     fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context) -> Poll<io::Result<()>> {
-        AsyncWrite::poll_close(self, cx)
+        self.get_mut().poll_finish(cx).map_err(Into::into)
     }
 }