Compare smol-hyper and hyper-futures for impl Read

Compare smol-hyper and hyper-futures for impl Read

(Jin Qing’s Column, Nov., 2024)

Hyper uses tokio’s AsyncRead/Write trait not the futures-0.3 one.
See: https://github.com/hyperium/hyper/issues/2024

There are at least 3 ways to implement hyper Read/Write for futures_io::AsyncRead/Write:

• smol-hyper: FuturesIo implements hyper I/O traits for futures-io implementors.
  • download: 45K
• hyper-futures: Compatibility layer for futures to use AsyncRead and AsyncWrite traits with hyper
  • download: 1413
• tokio_util::compat + hyper_util::rt::tokio:
  • first use tokio_util to implement tokio IO
  • then use TokioIo to implement hyper’s IO traits

Prefer smol-hyper or hyper-futures because they are directly.
The implementation of smol-hyper and hyper-futures are very similar.
Following is the comparison of impl Read.

smol-hyper

Revision: 4d6916333055d25896ddcd52ef6ff33af717e0e2
Author: Dependency Dog 
Date: 24.10.19 8:15:03
Message:
chore(deps): update rust crate hyper to v1.5.0

impl<T: futures_io::AsyncRead + ?Sized> hyper::rt::Read for FuturesIo<T> {
    #[inline]
    fn poll_read(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        mut buf: ReadBufCursor<'_>,
    ) -> Poll<io::Result<()>> {
        // Fill the read buffer with initialized data.
        let read_slice = unsafe {
            let buffer = buf.as_mut();
            buffer.as_mut_ptr().write_bytes(0, buffer.len());
            slice::from_raw_parts_mut(buffer.as_mut_ptr() as *mut u8, buffer.len())
        };

        // Read bytes from the underlying source.
        let n = match self.get_pin_mut().poll_read(cx, read_slice) {
            Poll::Ready(Ok(n)) => n,
            Poll::Ready(Err(e)) => return Poll::Ready(Err(e)),
            Poll::Pending => return Poll::Pending,
        };

        // Advance the buffer.
        unsafe {
            buf.advance(n);
        }

        Poll::Ready(Ok(()))
    }
}

hyper-futures

Revision: faeab613dc6a30a4439e0e29eedc13cd20693f63
Author: AlexSherb 
Date: 24.1.12 2:08:13
Message:
Removed dbg! calls. Version changed to 0.1.1

impl<T: AsyncRead + AsyncWrite> hyper::rt::Read for AsyncReadWriteCompat<T> {
    fn poll_read(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        mut buf: hyper::rt::ReadBufCursor<'_>,
    ) -> Poll<Result<(), std::io::Error>> {
        let buf_slice: &mut [u8] = unsafe { std::mem::transmute(buf.as_mut()) };
        match self.project().inner.poll_read(cx, buf_slice) {
            Poll::Ready(bytes_read) => {
                let bytes_read = bytes_read?;
                unsafe {
                    buf.advance(bytes_read);
                }
                Poll::Ready(Ok(()))
            }
            Poll::Pending => Poll::Pending,
        }
    }
}