Implement AsyncBufRead (#100)

* Implement AsyncBufRead for TlsStream types & Stream

* Implement AsyncRead using AsyncBufRead

* Reimplement AsyncRead for {server,client}::TlsStream in terms of AsyncBufRead

Cargo.toml

@@ -13,7 +13,7 @@ rust-version = "1.71"
 exclude = ["/.github", "/examples", "/scripts"]
 
 [dependencies]
-rustls = { version = "0.23.15", default-features = false, features = ["std"] }
+rustls = { version = "0.23.22", default-features = false, features = ["std"] }
 tokio = "1.0"
 
 [features]

src/client.rs

@@ -1,4 +1,4 @@
-use std::io;
+use std::io::{self, BufRead as _};
 #[cfg(unix)]
 use std::os::unix::io::{AsRawFd, RawFd};
 #[cfg(windows)]
@@ -9,7 +9,7 @@ use std::task::Waker;
 use std::task::{Context, Poll};
 
 use rustls::ClientConnection;
-use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
+use tokio::io::{AsyncBufRead, AsyncRead, AsyncWrite, ReadBuf};
 
 use crate::common::{IoSession, Stream, TlsState};
 
@@ -82,50 +82,69 @@ impl<IO> IoSession for TlsStream<IO> {
     }
 }
 
+#[cfg(feature = "early-data")]
+impl<IO> TlsStream<IO>
+where
+    IO: AsyncRead + AsyncWrite + Unpin,
+{
+    fn poll_early_data(&mut self, cx: &mut Context<'_>) {
+        // In the EarlyData state, we have not really established a Tls connection.
+        // Before writing data through `AsyncWrite` and completing the tls handshake,
+        // we ignore read readiness and return to pending.
+        //
+        // In order to avoid event loss,
+        // we need to register a waker and wake it up after tls is connected.
+        if self
+            .early_waker
+            .as_ref()
+            .filter(|waker| cx.waker().will_wake(waker))
+            .is_none()
+        {
+            self.early_waker = Some(cx.waker().clone());
+        }
+    }
+}
+
 impl<IO> AsyncRead for TlsStream<IO>
 where
     IO: AsyncRead + AsyncWrite + Unpin,
 {
     fn poll_read(
-        self: Pin<&mut Self>,
+        mut self: Pin<&mut Self>,
         cx: &mut Context<'_>,
         buf: &mut ReadBuf<'_>,
     ) -> Poll<io::Result<()>> {
+        let data = ready!(self.as_mut().poll_fill_buf(cx))?;
+        let len = data.len().min(buf.remaining());
+        buf.put_slice(&data[..len]);
+        self.consume(len);
+        Poll::Ready(Ok(()))
+    }
+}
+
+impl<IO> AsyncBufRead for TlsStream<IO>
+where
+    IO: AsyncRead + AsyncWrite + Unpin,
+{
+    fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
         match self.state {
             #[cfg(feature = "early-data")]
             TlsState::EarlyData(..) => {
-                let this = self.get_mut();
-
-                // In the EarlyData state, we have not really established a Tls connection.
-                // Before writing data through `AsyncWrite` and completing the tls handshake,
-                // we ignore read readiness and return to pending.
-                //
-                // In order to avoid event loss,
-                // we need to register a waker and wake it up after tls is connected.
-                if this
-                    .early_waker
-                    .as_ref()
-                    .filter(|waker| cx.waker().will_wake(waker))
-                    .is_none()
-                {
-                    this.early_waker = Some(cx.waker().clone());
-                }
-
+                self.get_mut().poll_early_data(cx);
                 Poll::Pending
             }
             TlsState::Stream | TlsState::WriteShutdown => {
                 let this = self.get_mut();
-                let mut stream =
+                let stream =
                     Stream::new(&mut this.io, &mut this.session).set_eof(!this.state.readable());
-                let prev = buf.remaining();
 
-                match stream.as_mut_pin().poll_read(cx, buf) {
-                    Poll::Ready(Ok(())) => {
-                        if prev == buf.remaining() || stream.eof {
+                match stream.poll_fill_buf(cx) {
+                    Poll::Ready(Ok(buf)) => {
+                        if buf.is_empty() {
                             this.state.shutdown_read();
                         }
 
-                        Poll::Ready(Ok(()))
+                        Poll::Ready(Ok(buf))
                     }
                     Poll::Ready(Err(err)) if err.kind() == io::ErrorKind::ConnectionAborted => {
                         this.state.shutdown_read();
@@ -134,9 +153,13 @@ where
                     output => output,
                 }
             }
-            TlsState::ReadShutdown | TlsState::FullyShutdown => Poll::Ready(Ok(())),
+            TlsState::ReadShutdown | TlsState::FullyShutdown => Poll::Ready(Ok(&[])),
         }
     }
+
+    fn consume(mut self: Pin<&mut Self>, amt: usize) {
+        self.session.reader().consume(amt);
+    }
 }
 
 impl<IO> AsyncWrite for TlsStream<IO>

src/common/mod.rs

@@ -1,10 +1,10 @@
-use std::io::{self, IoSlice, Read, Write};
+use std::io::{self, BufRead as _, IoSlice, Read, Write};
 use std::ops::{Deref, DerefMut};
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
 use rustls::{ConnectionCommon, SideData};
-use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
+use tokio::io::{AsyncBufRead, AsyncRead, AsyncWrite, ReadBuf};
 
 mod handshake;
 pub(crate) use handshake::{IoSession, MidHandshake};
@@ -180,18 +180,11 @@ where
             };
         }
     }
-}
 
-impl<IO: AsyncRead + AsyncWrite + Unpin, C, SD> AsyncRead for Stream<'_, IO, C>
-where
-    C: DerefMut + Deref<Target = ConnectionCommon<SD>>,
-    SD: SideData,
-{
-    fn poll_read(
-        mut self: Pin<&mut Self>,
-        cx: &mut Context<'_>,
-        buf: &mut ReadBuf<'_>,
-    ) -> Poll<io::Result<()>> {
+    pub(crate) fn poll_fill_buf(mut self, cx: &mut Context<'_>) -> Poll<io::Result<&'a [u8]>>
+    where
+        SD: 'a,
+    {
         let mut io_pending = false;
 
         // read a packet
@@ -209,22 +202,13 @@ where
             }
         }
 
-        match self.session.reader().read(buf.initialize_unfilled()) {
-            // If Rustls returns `Ok(0)` (while `buf` is non-empty), the peer closed the
-            // connection with a `CloseNotify` message and no more data will be forthcoming.
-            //
-            // Rustls yielded more data: advance the buffer, then see if more data is coming.
-            //
-            // We don't need to modify `self.eof` here, because it is only a temporary mark.
-            // rustls will only return 0 if is has received `CloseNotify`,
-            // in which case no additional processing is required.
-            Ok(n) => {
-                buf.advance(n);
-                Poll::Ready(Ok(()))
+        match self.session.reader().into_first_chunk() {
+            Ok(buf) => {
+                // Note that this could be empty (i.e. EOF) if a `CloseNotify` has been
+                // received and there is no more buffered data.
+                Poll::Ready(Ok(buf))
             }
-
-            // Rustls doesn't have more data to yield, but it believes the connection is open.
-            Err(ref err) if err.kind() == io::ErrorKind::WouldBlock => {
+            Err(e) if e.kind() == io::ErrorKind::WouldBlock => {
                 if !io_pending {
                     // If `wants_read()` is satisfied, rustls will not return `WouldBlock`.
                     // but if it does, we can try again.
@@ -236,9 +220,47 @@ where
 
                 Poll::Pending
             }
+            Err(e) => Poll::Ready(Err(e)),
+        }
+    }
+}
 
-            Err(err) => Poll::Ready(Err(err)),
+impl<'a, IO: AsyncRead + AsyncWrite + Unpin, C, SD> AsyncRead for Stream<'a, IO, C>
+where
+    C: DerefMut + Deref<Target = ConnectionCommon<SD>>,
+    SD: SideData + 'a,
+{
+    fn poll_read(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+        buf: &mut ReadBuf<'_>,
+    ) -> Poll<io::Result<()>> {
+        let data = ready!(self.as_mut().poll_fill_buf(cx))?;
+        let amount = buf.remaining().min(data.len());
+        buf.put_slice(&data[..amount]);
+        self.session.reader().consume(amount);
+        Poll::Ready(Ok(()))
+    }
+}
+
+impl<'a, IO: AsyncRead + AsyncWrite + Unpin, C, SD> AsyncBufRead for Stream<'a, IO, C>
+where
+    C: DerefMut + Deref<Target = ConnectionCommon<SD>>,
+    SD: SideData + 'a,
+{
+    fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
+        let this = self.get_mut();
+        Stream {
+            // reborrow
+            io: this.io,
+            session: this.session,
+            ..*this
         }
+        .poll_fill_buf(cx)
+    }
+
+    fn consume(mut self: Pin<&mut Self>, amt: usize) {
+        self.session.reader().consume(amt);
     }
 }
 

src/common/test_stream.rs

@@ -154,15 +154,20 @@ impl AsyncWrite for Eof {
 
 #[tokio::test]
 async fn stream_good() -> io::Result<()> {
-    stream_good_impl(false).await
+    stream_good_impl(false, false).await
 }
 
 #[tokio::test]
 async fn stream_good_vectored() -> io::Result<()> {
-    stream_good_impl(true).await
+    stream_good_impl(true, false).await
 }
 
-async fn stream_good_impl(vectored: bool) -> io::Result<()> {
+#[tokio::test]
+async fn stream_good_bufread() -> io::Result<()> {
+    stream_good_impl(false, true).await
+}
+
+async fn stream_good_impl(vectored: bool, bufread: bool) -> io::Result<()> {
     const FILE: &[u8] = include_bytes!("../../README.md");
 
     let (server, mut client) = make_pair();
@@ -177,7 +182,11 @@ async fn stream_good_impl(vectored: bool) -> io::Result<()> {
         let mut stream = Stream::new(&mut good, &mut client);
 
         let mut buf = Vec::new();
-        dbg!(stream.read_to_end(&mut buf).await)?;
+        if bufread {
+            dbg!(tokio::io::copy_buf(&mut stream, &mut buf).await)?;
+        } else {
+            dbg!(stream.read_to_end(&mut buf).await)?;
+        }
         assert_eq!(buf, FILE);
 
         dbg!(utils::write(&mut stream, b"Hello World!", vectored).await)?;

src/lib.rs

@@ -51,7 +51,7 @@ pub use rustls;
 use rustls::pki_types::ServerName;
 use rustls::server::AcceptedAlert;
 use rustls::{ClientConfig, ClientConnection, CommonState, ServerConfig, ServerConnection};
-use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
+use tokio::io::{AsyncBufRead, AsyncRead, AsyncWrite, ReadBuf};
 
 macro_rules! ready {
     ( $e:expr ) => {
@@ -545,6 +545,27 @@ where
     }
 }
 
+impl<T> AsyncBufRead for TlsStream<T>
+where
+    T: AsyncRead + AsyncWrite + Unpin,
+{
+    #[inline]
+    fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
+        match self.get_mut() {
+            TlsStream::Client(x) => Pin::new(x).poll_fill_buf(cx),
+            TlsStream::Server(x) => Pin::new(x).poll_fill_buf(cx),
+        }
+    }
+
+    #[inline]
+    fn consume(self: Pin<&mut Self>, amt: usize) {
+        match self.get_mut() {
+            TlsStream::Client(x) => Pin::new(x).consume(amt),
+            TlsStream::Server(x) => Pin::new(x).consume(amt),
+        }
+    }
+}
+
 impl<T> AsyncWrite for TlsStream<T>
 where
     T: AsyncRead + AsyncWrite + Unpin,