make server auto::Connection use hyper's IO instead of Tokios (#52)

Author: seanmonstar

src/common/rewind.rs

@@ -2,7 +2,7 @@ use std::marker::Unpin;
 use std::{cmp, io};
 
 use bytes::{Buf, Bytes};
-use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
+use hyper::rt::{Read, ReadBufCursor, Write};
 
 use std::{
     pin::Pin,
@@ -48,21 +48,21 @@ impl<T> Rewind<T> {
     // }
 }
 
-impl<T> AsyncRead for Rewind<T>
+impl<T> Read for Rewind<T>
 where
-    T: AsyncRead + Unpin,
+    T: Read + Unpin,
 {
     fn poll_read(
         mut self: Pin<&mut Self>,
         cx: &mut task::Context<'_>,
-        buf: &mut ReadBuf<'_>,
+        mut buf: ReadBufCursor<'_>,
     ) -> Poll<io::Result<()>> {
         if let Some(mut prefix) = self.pre.take() {
             // If there are no remaining bytes, let the bytes get dropped.
             if !prefix.is_empty() {
-                let copy_len = cmp::min(prefix.len(), buf.remaining());
+                let copy_len = cmp::min(prefix.len(), remaining(&mut buf));
                 // TODO: There should be a way to do following two lines cleaner...
-                buf.put_slice(&prefix[..copy_len]);
+                put_slice(&mut buf, &prefix[..copy_len]);
                 prefix.advance(copy_len);
                 // Put back what's left
                 if !prefix.is_empty() {
@@ -76,9 +76,36 @@ where
     }
 }
 
-impl<T> AsyncWrite for Rewind<T>
+fn remaining(cursor: &mut ReadBufCursor<'_>) -> usize {
+    // SAFETY:
+    // We do not uninitialize any set bytes.
+    unsafe { cursor.as_mut().len() }
+}
+
+// Copied from `ReadBufCursor::put_slice`.
+// If that becomes public, we could ditch this.
+fn put_slice(cursor: &mut ReadBufCursor<'_>, slice: &[u8]) {
+    assert!(
+        remaining(cursor) >= slice.len(),
+        "buf.len() must fit in remaining()"
+    );
+
+    let amt = slice.len();
+
+    // SAFETY:
+    // the length is asserted above
+    unsafe {
+        cursor.as_mut()[..amt]
+            .as_mut_ptr()
+            .cast::<u8>()
+            .copy_from_nonoverlapping(slice.as_ptr(), amt);
+        cursor.advance(amt);
+    }
+}
+
+impl<T> Write for Rewind<T>
 where
-    T: AsyncWrite + Unpin,
+    T: Write + Unpin,
 {
     fn poll_write(
         mut self: Pin<&mut Self>,
@@ -109,10 +136,9 @@ where
     }
 }
 
+/*
 #[cfg(test)]
 mod tests {
-    // FIXME: re-implement tests with `async/await`, this import should
-    // trigger a warning to remind us
     use super::Rewind;
     use bytes::Bytes;
     use tokio::io::AsyncReadExt;
@@ -159,3 +185,4 @@ mod tests {
         stream.read_exact(&mut buf).await.expect("read1");
     }
 }
+*/

src/server/conn/auto.rs

@@ -13,14 +13,13 @@ use http::{Request, Response};
 use http_body::Body;
 use hyper::{
     body::Incoming,
-    rt::{bounds::Http2ServerConnExec, Timer},
+    rt::{bounds::Http2ServerConnExec, Read, ReadBuf, Timer, Write},
     server::conn::{http1, http2},
     service::Service,
 };
 use pin_project_lite::pin_project;
-use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
 
-use crate::{common::rewind::Rewind, rt::TokioIo};
+use crate::common::rewind::Rewind;
 
 type Result<T> = std::result::Result<T, Box<dyn std::error::Error + Send + Sync>>;
 
@@ -74,11 +73,10 @@ impl<E> Builder<E> {
         B: Body + Send + 'static,
         B::Data: Send,
         B::Error: Into<Box<dyn StdError + Send + Sync>>,
-        I: AsyncRead + AsyncWrite + Unpin + 'static,
+        I: Read + Write + Unpin + 'static,
         E: Http2ServerConnExec<S::Future, B>,
     {
         let (version, io) = read_version(io).await?;
-        let io = TokioIo::new(io);
         match version {
             Version::H1 => self.http1.serve_connection(io, service).await?,
             Version::H2 => self.http2.serve_connection(io, service).await?,
@@ -98,11 +96,10 @@ impl<E> Builder<E> {
         B: Body + Send + 'static,
         B::Data: Send,
         B::Error: Into<Box<dyn StdError + Send + Sync>>,
-        I: AsyncRead + AsyncWrite + Unpin + Send + 'static,
+        I: Read + Write + Unpin + Send + 'static,
         E: Http2ServerConnExec<S::Future, B>,
     {
         let (version, io) = read_version(io).await?;
-        let io = TokioIo::new(io);
         match version {
             Version::H1 => {
                 self.http1
@@ -123,12 +120,14 @@ enum Version {
 }
 async fn read_version<'a, A>(mut reader: A) -> IoResult<(Version, Rewind<A>)>
 where
-    A: AsyncRead + Unpin,
+    A: Read + Unpin,
 {
-    let mut buf = [0; 24];
+    use std::mem::MaybeUninit;
+
+    let mut buf = [MaybeUninit::uninit(); 24];
     let (version, buf) = ReadVersion {
         reader: &mut reader,
-        buf: ReadBuf::new(&mut buf),
+        buf: ReadBuf::uninit(&mut buf),
         version: Version::H1,
         _pin: PhantomPinned,
     }
@@ -148,21 +147,21 @@ pin_project! {
 
 impl<A> Future for ReadVersion<'_, A>
 where
-    A: AsyncRead + Unpin + ?Sized,
+    A: Read + Unpin + ?Sized,
 {
     type Output = IoResult<(Version, Vec<u8>)>;
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<IoResult<(Version, Vec<u8>)>> {
         let this = self.project();
 
-        while this.buf.remaining() != 0 {
+        while this.buf.filled().len() < H2_PREFACE.len() {
             if this.buf.filled() != &H2_PREFACE[0..this.buf.filled().len()] {
                 return Poll::Ready(Ok((*this.version, this.buf.filled().to_vec())));
             }
             // if our buffer is empty, then we need to read some data to continue.
-            let rem = this.buf.remaining();
-            ready!(Pin::new(&mut *this.reader).poll_read(cx, this.buf))?;
-            if this.buf.remaining() == rem {
+            let len = this.buf.filled().len();
+            ready!(Pin::new(&mut *this.reader).poll_read(cx, this.buf.unfilled()))?;
+            if this.buf.filled().len() == len {
                 return Err(IoError::new(ErrorKind::UnexpectedEof, "early eof")).into();
             }
         }
@@ -302,7 +301,7 @@ impl<E> Http1Builder<'_, E> {
         B: Body + Send + 'static,
         B::Data: Send,
         B::Error: Into<Box<dyn StdError + Send + Sync>>,
-        I: AsyncRead + AsyncWrite + Unpin + 'static,
+        I: Read + Write + Unpin + 'static,
         E: Http2ServerConnExec<S::Future, B>,
     {
         self.inner.serve_connection(io, service).await
@@ -450,7 +449,7 @@ impl<E> Http2Builder<'_, E> {
         B: Body + Send + 'static,
         B::Data: Send,
         B::Error: Into<Box<dyn StdError + Send + Sync>>,
-        I: AsyncRead + AsyncWrite + Unpin + 'static,
+        I: Read + Write + Unpin + 'static,
         E: Http2ServerConnExec<S::Future, B>,
     {
         self.inner.serve_connection(io, service).await
@@ -562,6 +561,7 @@ mod tests {
         tokio::spawn(async move {
             loop {
                 let (stream, _) = listener.accept().await.unwrap();
+                let stream = TokioIo::new(stream);
                 tokio::task::spawn(async move {
                     let _ = auto::Builder::new(TokioExecutor::new())
                         .serve_connection(stream, service_fn(hello))