Function read_framed

nodedb-cluster/src/mirror/handshake.rs:198–223

Read a framed message: `[discriminant u8][len u32 BE][payload bytes]`.

(reader: &mut R)

/// Read a framed message: `[discriminant u8][len u32 BE][payload bytes]`.
async fn read_framed<R: AsyncRead + Unpin>(reader: &mut R) -> Result<(u8, Vec<u8>), MirrorError> {
    let mut header = [0u8; 5];
    reader
        .read_exact(&mut header)
        .await
        .map_err(|e| MirrorError::Transport {
            detail: format!("read framed header: {e}"),
        })?;
    let discriminant = header[0];
    let len = u32::from_be_bytes([header[1], header[2], header[3], header[4]]) as usize;

    if len > MAX_HANDSHAKE_PAYLOAD {
        return Err(MirrorError::HandshakeCodec {
            detail: format!("handshake payload {len} bytes exceeds max {MAX_HANDSHAKE_PAYLOAD}"),
        });
    }

    let mut payload = vec![0u8; len];
    reader
        .read_exact(&mut payload)
        .await
        .map_err(|e| MirrorError::Transport {
            detail: format!("read framed payload: {e}"),
        })?;
    Ok((discriminant, payload))
}

#[cfg(test)]
mod tests {