use tokio_util::codec;
use bytes::{Bytes, Buf};
#[derive(Default)]
pub struct GitCodec;
impl codec::Decoder for GitCodec {
type Item = Bytes;
type Error = anyhow::Error;
fn decode(&mut self, src: &mut bytes::BytesMut) -> Result<Option<Self::Item>, Self::Error> {
if src.len() < 4 {
return Ok(None);
}
let mut length_bytes = [0u8; 4];
length_bytes.copy_from_slice(&src[..4]);
let length = u16::from_str_radix(std::str::from_utf8(&length_bytes)?, 16)? as usize;
if length == 0
|| length == 1
|| length == 2
{
src.advance(4);
return self.decode(src);
}
if length > 65520 || length <= 4 {
return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "protocol abuse").into());
}
if src.len() < length {
src.reserve(length - src.len());
return Ok(None);
}
let mut bytes = src.split_to(length);
bytes.advance(4);
if bytes.ends_with(b"\n") {
bytes.truncate(bytes.len() - 1);
}
Ok(Some(bytes.freeze()))
}
}
#[cfg(test)]
mod test {
use tokio_util::codec::Decoder;
use bytes::BytesMut;
use std::fmt::Write;
#[test]
fn decode() {
let mut codec = super::GitCodec;
let mut bytes = BytesMut::new();
bytes.write_str("0015agent=git/2.32.0").unwrap();
let res = codec.decode(&mut bytes).unwrap();
assert_eq!(res, None);
bytes.write_char('\n').unwrap();
let res = codec.decode(&mut bytes).unwrap();
assert_eq!(res.as_deref(), Some("agent=git/2.32.0".as_bytes()));
}
}