Review comments

Signed-off-by: John Nunley <[email protected]>

examples/windows-uds.rs

@@ -6,6 +6,122 @@
 //! cargo run --example windows-uds
 //! ```
 
+#[cfg(windows)]
+fn main() -> std::io::Result<()> {
+    use std::ops::Deref;
+    use std::os::windows::io::{AsRawSocket, AsSocket, BorrowedSocket};
+    use std::path::PathBuf;
+
+    use async_io::Async;
+    use blocking::Unblock;
+    use futures_lite::{future, prelude::*};
+    use std::io;
+    use tempfile::tempdir;
+
+    // n.b.: notgull: uds_windows does not support I/O safety uet, hence the wrapper types
+
+    struct UnixListener(uds_windows::UnixListener);
+
+    impl From<uds_windows::UnixListener> for UnixListener {
+        fn from(ul: uds_windows::UnixListener) -> Self {
+            Self(ul)
+        }
+    }
+
+    impl Deref for UnixListener {
+        type Target = uds_windows::UnixListener;
+
+        fn deref(&self) -> &uds_windows::UnixListener {
+            &self.0
+        }
+    }
+
+    impl AsSocket for UnixListener {
+        fn as_socket(&self) -> BorrowedSocket<'_> {
+            unsafe { BorrowedSocket::borrow_raw(self.as_raw_socket()) }
+        }
+    }
+
+    struct UnixStream(uds_windows::UnixStream);
+
+    impl From<uds_windows::UnixStream> for UnixStream {
+        fn from(ul: uds_windows::UnixStream) -> Self {
+            Self(ul)
+        }
+    }
+
+    impl Deref for UnixStream {
+        type Target = uds_windows::UnixStream;
+
+        fn deref(&self) -> &uds_windows::UnixStream {
+            &self.0
+        }
+    }
+
+    impl AsSocket for UnixStream {
+        fn as_socket(&self) -> BorrowedSocket<'_> {
+            unsafe { BorrowedSocket::borrow_raw(self.as_raw_socket()) }
+        }
+    }
+
+    impl io::Read for UnixStream {
+        fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+            io::Read::read(&mut self.0, buf)
+        }
+    }
+
+    impl io::Write for UnixStream {
+        fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+            io::Write::write(&mut self.0, buf)
+        }
+
+        fn flush(&mut self) -> io::Result<()> {
+            io::Write::flush(&mut self.0)
+        }
+    }
+
+    unsafe impl async_io::IoSafe for UnixStream {}
+
+    async fn client(addr: PathBuf) -> io::Result<()> {
+        // Connect to the address.
+        let stream = Async::new(UnixStream::from(uds_windows::UnixStream::connect(addr)?))?;
+        println!("Connected to {:?}", stream.get_ref().peer_addr()?);
+
+        // Pipe the stream to stdout.
+        let mut stdout = Unblock::new(std::io::stdout());
+        futures_lite::io::copy(stream, &mut stdout).await?;
+        Ok(())
+    }
+
+    let dir = tempdir()?;
+    let path = dir.path().join("socket");
+
+    future::block_on(async {
+        // Create a listener.
+        let listener = Async::new(UnixListener::from(uds_windows::UnixListener::bind(&path)?))?;
+        println!("Listening on {:?}", listener.get_ref().local_addr()?);
+
+        future::try_zip(
+            async {
+                // Accept the client.
+                let (stream, _) = listener.read_with(|l| l.accept()).await?;
+                println!("Accepted a client");
+
+                // Send a message, drop the stream, and wait for the client.
+                Async::new(UnixStream::from(stream))?
+                    .write_all(b"Hello!\n")
+                    .await?;
+                Ok(())
+            },
+            client(path),
+        )
+        .await?;
+
+        Ok(())
+    })
+}
+
+#[cfg(not(windows))]
 fn main() {
-    println!("TODO: Restore this example from git once uds_windows implements I/O safety");
+    println!("This example works only on Windows!");
 }

src/lib.rs

@@ -1153,7 +1153,7 @@ impl<T> Drop for Async<T> {
 /// happen if the inner resource (the [`TcpStream`], [`UnixListener`] or other `T`) is moved out
 /// and dropped before the [`Async`]. Because of this, functions that grant mutable access to
 /// the inner type are unsafe, as there is no way to guarantee that the source won't be dropped
-/// and a dangling pointer won't be left behind.
+/// and a dangling handle won't be left behind.
 ///
 /// Unfortunately this extends to implementations of [`Read`] and [`Write`]. Since methods on those
 /// traits take `&mut`, there is no guarantee that the implementor of those traits won't move the
@@ -1205,6 +1205,7 @@ unsafe impl<T: IoSafe + Write> IoSafe for std::io::BufWriter<T> {}
 unsafe impl<T: IoSafe + Write> IoSafe for std::io::LineWriter<T> {}
 unsafe impl<T: IoSafe + ?Sized> IoSafe for &mut T {}
 unsafe impl<T: IoSafe + ?Sized> IoSafe for Box<T> {}
+unsafe impl<T: Clone + IoSafe + ?Sized> IoSafe for std::borrow::Cow<'_, T> {}
 
 impl<T: IoSafe + Read> AsyncRead for Async<T> {
     fn poll_read(