From 2dec3b725f865f9b5959db0ed3712167aeac1194 Mon Sep 17 00:00:00 2001
From: Taiki Endo <te316e89@gmail.com>
Date: Sat, 14 Nov 2020 05:46:10 +0900
Subject: [PATCH] Remove pin-related unsafe code

---
 src/async_impl/body.rs   | 20 +++++++++++---------
 src/async_impl/client.rs | 40 ++++++++++++++++++++++++----------------
 2 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/src/async_impl/body.rs b/src/async_impl/body.rs
index 3e58666..762d70a 100644
--- a/src/async_impl/body.rs
+++ b/src/async_impl/body.rs
@@ -6,6 +6,7 @@ use std::task::{Context, Poll};
 use bytes::Bytes;
 use futures_core::Stream;
 use http_body::Body as HttpBody;
+use pin_project_lite::pin_project;
 use tokio::time::Delay;
 
 /// An asynchronous request body.
@@ -30,7 +31,12 @@ enum Inner {
     },
 }
 
-struct WrapStream<S>(S);
+pin_project! {
+    struct WrapStream<S> {
+        #[pin]
+        inner: S,
+    }
+}
 
 struct WrapHyper(hyper::Body);
 
@@ -86,9 +92,9 @@ impl Body {
     {
         use futures_util::TryStreamExt;
 
-        let body = Box::pin(WrapStream(
-            stream.map_ok(Bytes::from).map_err(Into::into),
-        ));
+        let body = Box::pin(WrapStream {
+            inner: stream.map_ok(Bytes::from).map_err(Into::into),
+        });
         Body {
             inner: Inner::Streaming {
                 body,
@@ -279,11 +285,7 @@ where
         self: Pin<&mut Self>,
         cx: &mut Context,
     ) -> Poll<Option<Result<Self::Data, Self::Error>>> {
-        // safe pin projection
-        let item =
-            futures_core::ready!(
-                unsafe { Pin::new_unchecked(&mut self.get_unchecked_mut().0) }.poll_next(cx)?
-            );
+        let item = futures_core::ready!(self.project().inner.poll_next(cx)?);
 
         Poll::Ready(item.map(|val| Ok(val.into())))
     }
diff --git a/src/async_impl/client.rs b/src/async_impl/client.rs
index ff103f7..15af416 100644
--- a/src/async_impl/client.rs
+++ b/src/async_impl/client.rs
@@ -25,6 +25,7 @@ use std::future::Future;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 use tokio::time::Delay;
+use pin_project_lite::pin_project;
 
 use log::debug;
 
@@ -1265,8 +1266,11 @@ impl ClientRef {
     }
 }
 
-pub(super) struct Pending {
-    inner: PendingInner,
+pin_project! {
+    pub(super) struct Pending {
+        #[pin]
+        inner: PendingInner,
+    }
 }
 
 enum PendingInner {
@@ -1274,35 +1278,39 @@ enum PendingInner {
     Error(Option<crate::Error>),
 }
 
-struct PendingRequest {
-    method: Method,
-    url: Url,
-    headers: HeaderMap,
-    body: Option<Option<Bytes>>,
+pin_project! {
+    struct PendingRequest {
+        method: Method,
+        url: Url,
+        headers: HeaderMap,
+        body: Option<Option<Bytes>>,
 
-    urls: Vec<Url>,
+        urls: Vec<Url>,
 
-    client: Arc<ClientRef>,
+        client: Arc<ClientRef>,
 
-    in_flight: ResponseFuture,
-    timeout: Option<Delay>,
+        #[pin]
+        in_flight: ResponseFuture,
+        #[pin]
+        timeout: Option<Delay>,
+    }
 }
 
 impl PendingRequest {
     fn in_flight(self: Pin<&mut Self>) -> Pin<&mut ResponseFuture> {
-        unsafe { Pin::map_unchecked_mut(self, |x| &mut x.in_flight) }
+        self.project().in_flight
     }
 
     fn timeout(self: Pin<&mut Self>) -> Pin<&mut Option<Delay>> {
-        unsafe { Pin::map_unchecked_mut(self, |x| &mut x.timeout) }
+        self.project().timeout
     }
 
     fn urls(self: Pin<&mut Self>) -> &mut Vec<Url> {
-        unsafe { &mut Pin::get_unchecked_mut(self).urls }
+        self.project().urls
     }
 
     fn headers(self: Pin<&mut Self>) -> &mut HeaderMap {
-        unsafe { &mut Pin::get_unchecked_mut(self).headers }
+        self.project().headers
     }
 }
 
@@ -1314,7 +1322,7 @@ impl Pending {
     }
 
     fn inner(self: Pin<&mut Self>) -> Pin<&mut PendingInner> {
-        unsafe { Pin::map_unchecked_mut(self, |x| &mut x.inner) }
+        self.project().inner
     }
 }