From 9b7f7a02c0d3e1239ef8fbe3eeb1f4779ea31972 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Tue, 26 Nov 2019 22:44:05 +0100
Subject: [PATCH] Use #[pin_project] in stream implementation to get rid of
 remaining unsafe code

Now the whole crate has no unsafe code left.
---
 src/stream.rs | 76 +++++++++++++++++++--------------------------------
 1 file changed, 28 insertions(+), 48 deletions(-)

diff --git a/src/stream.rs b/src/stream.rs
index 424e9d7..9fd9e2a 100644
--- a/src/stream.rs
+++ b/src/stream.rs
@@ -3,85 +3,65 @@
 //!  There is no dependency on actual TLS implementations. Everything like
 //! `native_tls` or `openssl` will work as long as there is a TLS stream supporting standard
 //! `AsyncRead + AsyncWrite` traits.
+use pin_project::{pin_project, project};
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
 use futures::io::{AsyncRead, AsyncWrite};
 
 /// Stream, either plain TCP or TLS.
+#[pin_project]
 pub enum Stream<S, T> {
     /// Unencrypted socket stream.
-    Plain(S),
+    Plain(#[pin] S),
     /// Encrypted socket stream.
-    Tls(T),
+    Tls(#[pin] T),
 }
 
 impl<S: AsyncRead + Unpin, T: AsyncRead + Unpin> AsyncRead for Stream<S, T> {
+    #[project]
     fn poll_read(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context<'_>,
         buf: &mut [u8],
     ) -> Poll<std::io::Result<usize>> {
-        match *self {
-            Stream::Plain(ref mut s) => {
-                let pinned = unsafe { Pin::new_unchecked(s) };
-                pinned.poll_read(cx, buf)
-            }
-            Stream::Tls(ref mut s) => {
-                let pinned = unsafe { Pin::new_unchecked(s) };
-                pinned.poll_read(cx, buf)
-            }
+        #[project]
+        match self.project() {
+            Stream::Plain(ref mut s) => Pin::new(s).poll_read(cx, buf),
+            Stream::Tls(ref mut s) => Pin::new(s).poll_read(cx, buf),
         }
     }
 }
 
 impl<S: AsyncWrite + Unpin, T: AsyncWrite + Unpin> AsyncWrite for Stream<S, T> {
+    #[project]
     fn poll_write(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context<'_>,
         buf: &[u8],
     ) -> Poll<Result<usize, std::io::Error>> {
-        match *self {
-            Stream::Plain(ref mut s) => {
-                let pinned = unsafe { Pin::new_unchecked(s) };
-                pinned.poll_write(cx, buf)
-            }
-            Stream::Tls(ref mut s) => {
-                let pinned = unsafe { Pin::new_unchecked(s) };
-                pinned.poll_write(cx, buf)
-            }
+        #[project]
+        match self.project() {
+            Stream::Plain(ref mut s) => Pin::new(s).poll_write(cx, buf),
+            Stream::Tls(ref mut s) => Pin::new(s).poll_write(cx, buf),
         }
     }
 
-    fn poll_flush(
-        mut self: Pin<&mut Self>,
-        cx: &mut Context<'_>,
-    ) -> Poll<Result<(), std::io::Error>> {
-        match *self {
-            Stream::Plain(ref mut s) => {
-                let pinned = unsafe { Pin::new_unchecked(s) };
-                pinned.poll_flush(cx)
-            }
-            Stream::Tls(ref mut s) => {
-                let pinned = unsafe { Pin::new_unchecked(s) };
-                pinned.poll_flush(cx)
-            }
+    #[project]
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), std::io::Error>> {
+        #[project]
+        match self.project() {
+            Stream::Plain(ref mut s) => Pin::new(s).poll_flush(cx),
+            Stream::Tls(ref mut s) => Pin::new(s).poll_flush(cx),
         }
     }
 
-    fn poll_close(
-        mut self: Pin<&mut Self>,
-        cx: &mut Context<'_>,
-    ) -> Poll<Result<(), std::io::Error>> {
-        match *self {
-            Stream::Plain(ref mut s) => {
-                let pinned = unsafe { Pin::new_unchecked(s) };
-                pinned.poll_close(cx)
-            }
-            Stream::Tls(ref mut s) => {
-                let pinned = unsafe { Pin::new_unchecked(s) };
-                pinned.poll_close(cx)
-            }
+    #[project]
+    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), std::io::Error>> {
+        #[project]
+        match self.project() {
+            Stream::Plain(ref mut s) => Pin::new(s).poll_close(cx),
+            Stream::Tls(ref mut s) => Pin::new(s).poll_close(cx),
         }
     }
 }