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use bytes::BytesMut;
use futures::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
use std::{convert::TryInto, io::Result};
pub async fn read_u16frame<'stream, 'buf, 'c, TSocket>(
mut stream: &'stream mut TSocket,
buf: &'buf mut BytesMut,
) -> Result<()>
where
'stream: 'c,
'buf: 'c,
TSocket: AsyncRead + Unpin,
{
let len = read_u16frame_len(&mut stream).await?;
buf.resize(len as usize, 0);
stream.read_exact(buf.as_mut()).await?;
Ok(())
}
async fn read_u16frame_len<TSocket>(stream: &mut TSocket) -> Result<u16>
where
TSocket: AsyncRead + Unpin,
{
let mut len_buf = [0, 0];
stream.read_exact(&mut len_buf).await?;
Ok(u16::from_be_bytes(len_buf))
}
pub async fn write_u16frame<'stream, 'buf, 'c, TSocket>(
mut stream: &'stream mut TSocket,
buf: &'buf [u8],
) -> Result<()>
where
'stream: 'c,
'buf: 'c,
TSocket: AsyncWrite + Unpin,
{
let len = buf
.len()
.try_into()
.map_err(|_e| std::io::Error::new(std::io::ErrorKind::Other, "Too big"))?;
write_u16frame_len(&mut stream, len).await?;
stream.write_all(buf).await?;
Ok(())
}
async fn write_u16frame_len<TSocket>(stream: &mut TSocket, len: u16) -> Result<()>
where
TSocket: AsyncWrite + Unpin,
{
let len = u16::to_be_bytes(len);
stream.write_all(&len).await?;
Ok(())
}
#[cfg(test)]
mod test {
use super::{read_u16frame, read_u16frame_len, write_u16frame, write_u16frame_len};
use bytes::BytesMut;
use futures::{executor::block_on, io::AsyncWriteExt};
use memsocket::MemorySocket;
use std::io::Result;
#[test]
fn write_read_u16frame_len() -> Result<()> {
let (mut a, mut b) = MemorySocket::new_pair();
block_on(write_u16frame_len(&mut a, 17))?;
block_on(a.flush())?;
let len = block_on(read_u16frame_len(&mut b))?;
assert_eq!(len, 17);
Ok(())
}
#[test]
fn read_u16frame_len_eof() -> Result<()> {
let (mut a, mut b) = MemorySocket::new_pair();
block_on(a.write_all(&[42]))?;
block_on(a.flush())?;
drop(a);
let result = block_on(read_u16frame_len(&mut b));
assert!(result.is_err());
Ok(())
}
#[test]
fn write_u16frame_len_eof() {
let (mut a, b) = MemorySocket::new_pair();
drop(b);
let result = block_on(a.write_all(&[42]));
assert!(result.is_err());
}
#[test]
fn write_read_u16frame() -> Result<()> {
let (mut a, mut b) = MemorySocket::new_pair();
block_on(write_u16frame(&mut a, b"The Name of the Wind"))?;
block_on(a.flush())?;
let mut buf = BytesMut::new();
block_on(read_u16frame(&mut b, &mut buf))?;
assert_eq!(buf.as_ref(), b"The Name of the Wind");
Ok(())
}
#[test]
fn write_read_multiple_u16frames() -> Result<()> {
let (mut a, mut b) = MemorySocket::new_pair();
block_on(write_u16frame(&mut a, b"The Name of the Wind"))?;
block_on(write_u16frame(&mut b, b"The Wise Man's Fear"))?;
block_on(b.flush())?;
block_on(write_u16frame(&mut a, b"The Doors of Stone"))?;
block_on(a.flush())?;
let mut buf = BytesMut::new();
block_on(read_u16frame(&mut b, &mut buf))?;
assert_eq!(buf.as_ref(), b"The Name of the Wind");
block_on(read_u16frame(&mut b, &mut buf))?;
assert_eq!(buf.as_ref(), b"The Doors of Stone");
block_on(read_u16frame(&mut a, &mut buf))?;
assert_eq!(buf.as_ref(), b"The Wise Man's Fear");
Ok(())
}
#[test]
fn write_large_u16frame() {
let (mut a, _b) = MemorySocket::new_pair();
let mut buf = Vec::new();
buf.resize((u16::max_value() as usize) * 2, 0);
let result = block_on(write_u16frame(&mut a, &buf));
assert!(result.is_err());
}
}