From 745c78618479c4177647e4d7fed97d5fd2d00d4f Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Thu, 1 Sep 2022 11:34:53 +0200
Subject: [PATCH] Also encode errorkind in stream

---
 src/error.rs  | 36 ++++++++++++++++++++++++++++++++++++
 src/recv.rs   |  7 ++++---
 src/send.rs   | 23 ++++++++++++++++-------
 src/stream.rs | 36 ------------------------------------
 4 files changed, 56 insertions(+), 46 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index f374341..2fa4594 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -109,3 +109,39 @@ where
 		}
 	}
 }
+
+// ---- Helpers for serializing I/O Errors
+
+pub(crate) fn u8_to_io_errorkind(v: u8) -> std::io::ErrorKind {
+	use std::io::ErrorKind;
+	match v {
+		101 => ErrorKind::ConnectionAborted,
+		102 => ErrorKind::BrokenPipe,
+		103 => ErrorKind::WouldBlock,
+		104 => ErrorKind::InvalidInput,
+		105 => ErrorKind::InvalidData,
+		106 => ErrorKind::TimedOut,
+		107 => ErrorKind::Interrupted,
+		108 => ErrorKind::UnexpectedEof,
+		109 => ErrorKind::OutOfMemory,
+		110 => ErrorKind::ConnectionReset,
+		_ => ErrorKind::Other,
+	}
+}
+
+pub(crate) fn io_errorkind_to_u8(kind: std::io::ErrorKind) -> u8 {
+	use std::io::ErrorKind;
+	match kind {
+		ErrorKind::ConnectionAborted => 101,
+		ErrorKind::BrokenPipe => 102,
+		ErrorKind::WouldBlock => 103,
+		ErrorKind::InvalidInput => 104,
+		ErrorKind::InvalidData => 105,
+		ErrorKind::TimedOut => 106,
+		ErrorKind::Interrupted => 107,
+		ErrorKind::UnexpectedEof => 108,
+		ErrorKind::OutOfMemory => 109,
+		ErrorKind::ConnectionReset => 110,
+		_ => 100,
+	}
+}
diff --git a/src/recv.rs b/src/recv.rs
index f8d68da..f8606f3 100644
--- a/src/recv.rs
+++ b/src/recv.rs
@@ -81,9 +81,10 @@ pub(crate) trait RecvLoop: Sync + 'static {
 			read.read_exact(&mut next_slice[..]).await?;
 
 			let packet = if is_error {
-				let msg = String::from_utf8(next_slice).unwrap_or("<invalid utf8 error message>".into());
-				debug!("recv_loop: got id {}, error: {}", id, msg);
-				Some(Err(std::io::Error::new(std::io::ErrorKind::Other, msg)))
+				let kind = u8_to_io_errorkind(next_slice[0]);
+				let msg = std::str::from_utf8(&next_slice[1..]).unwrap_or("<invalid utf8 error message>");
+				debug!("recv_loop: got id {}, error {:?}: {}", id, kind, msg);
+				Some(Err(std::io::Error::new(kind, msg.to_string())))
 			} else {
 				trace!(
 					"recv_loop: got id {}, size {}, has_cont {}",
diff --git a/src/send.rs b/src/send.rs
index f362962..287fe40 100644
--- a/src/send.rs
+++ b/src/send.rs
@@ -4,7 +4,7 @@ use std::sync::Arc;
 use std::task::{Context, Poll};
 
 use async_trait::async_trait;
-use bytes::Bytes;
+use bytes::{Bytes, BytesMut, BufMut};
 use log::*;
 
 use futures::AsyncWriteExt;
@@ -22,7 +22,11 @@ use crate::stream::*;
 //		CHUNK_HAS_CONTINUATION when this is not the last chunk of the stream
 //		ERROR_MARKER if this chunk denotes an error
 //		(these two flags are exclusive, an error denotes the end of the stream)
-// - [u8; chunk_length] chunk data / error message
+// - [u8; chunk_length], either
+//   - if not error: chunk data
+//   - if error:
+//       - u8: error kind, encoded using error::io_errorkind_to_u8
+//       - rest: error message
 
 pub(crate) type RequestID = u32;
 pub(crate) type ChunkLength = u16;
@@ -136,12 +140,17 @@ impl DataFrame {
 				Self::Data(bytes, has_cont)
 			}
 			Err(e) => {
-				let msg = format!("{}", e);
-				let mut msg = Bytes::from(msg.into_bytes());
-				if msg.len() > MAX_CHUNK_LENGTH as usize {
-					msg = msg.slice(..MAX_CHUNK_LENGTH as usize);
+				let mut buf = BytesMut::new();
+				buf.put_u8(io_errorkind_to_u8(e.kind()));
+
+				let msg = format!("{}", e).into_bytes();
+				if msg.len() > (MAX_CHUNK_LENGTH - 1) as usize {
+					buf.put(&msg[..(MAX_CHUNK_LENGTH - 1) as usize]);
+				} else {
+					buf.put(&msg[..]);
 				}
-				Self::Error(msg)
+
+				Self::Error(buf.freeze())
 			}
 		}
 	}
diff --git a/src/stream.rs b/src/stream.rs
index 3518246..6e00e5f 100644
--- a/src/stream.rs
+++ b/src/stream.rs
@@ -150,42 +150,6 @@ impl<'a> Future for ByteStreamReadExact<'a> {
 
 // ----
 
-/*
-fn u8_to_io_error(v: u8) -> std::io::Error {
-	use std::io::{Error, ErrorKind};
-	let kind = match v {
-		101 => ErrorKind::ConnectionAborted,
-		102 => ErrorKind::BrokenPipe,
-		103 => ErrorKind::WouldBlock,
-		104 => ErrorKind::InvalidInput,
-		105 => ErrorKind::InvalidData,
-		106 => ErrorKind::TimedOut,
-		107 => ErrorKind::Interrupted,
-		108 => ErrorKind::UnexpectedEof,
-		109 => ErrorKind::OutOfMemory,
-		110 => ErrorKind::ConnectionReset,
-		_ => ErrorKind::Other,
-	};
-	Error::new(kind, "(in netapp stream)")
-}
-
-fn io_error_to_u8(e: std::io::Error) -> u8 {
-	use std::io::ErrorKind;
-	match e.kind() {
-		ErrorKind::ConnectionAborted => 101,
-		ErrorKind::BrokenPipe => 102,
-		ErrorKind::WouldBlock => 103,
-		ErrorKind::InvalidInput => 104,
-		ErrorKind::InvalidData => 105,
-		ErrorKind::TimedOut => 106,
-		ErrorKind::Interrupted => 107,
-		ErrorKind::UnexpectedEof => 108,
-		ErrorKind::OutOfMemory => 109,
-		ErrorKind::ConnectionReset => 110,
-		_ => 100,
-	}
-}
-*/
 
 pub fn asyncread_stream<R: AsyncRead + Send + Sync + 'static>(reader: R) -> ByteStream {
 	Box::pin(tokio_util::io::ReaderStream::new(reader))