refactor(net): clarify io_util code a bit

Author: CBenoit

crates/net/src/websocket/io_util.rs

@@ -22,6 +22,19 @@ impl WebSocket {
     }
 }
 
+macro_rules! try_in_poll_io {
+    ($expr:expr) => {{
+        match $expr {
+            Ok(o) => o,
+            // WebSocket is closed, nothing more to read or write
+            Err(WebSocketError::ConnectionClose(event)) if event.was_clean => {
+                return Poll::Ready(Ok(0));
+            }
+            Err(e) => return Poll::Ready(Err(io::Error::new(io::ErrorKind::Other, e))),
+        }
+    }};
+}
+
 #[cfg_attr(docsrs, doc(cfg(feature = "io-util")))]
 impl AsyncRead for WebSocket {
     fn poll_read(
@@ -33,14 +46,10 @@ impl AsyncRead for WebSocket {
             data
         } else {
             match ready!(self.as_mut().poll_next(cx)) {
-                Some(Ok(m)) => match m {
+                Some(item) => match try_in_poll_io!(item) {
                     WebSocketMessage::Text(s) => s.into_bytes(),
                     WebSocketMessage::Bytes(data) => data,
                 },
-                Some(Err(WebSocketError::ConnectionClose(event))) if event.was_clean == true => {
-                    return Poll::Ready(Ok(0));
-                }
-                Some(Err(e)) => return Poll::Ready(Err(io::Error::new(io::ErrorKind::Other, e))),
                 None => return Poll::Ready(Ok(0)),
             }
         };
@@ -64,26 +73,14 @@ impl AsyncWrite for WebSocket {
         cx: &mut Context<'_>,
         buf: &[u8],
     ) -> Poll<io::Result<usize>> {
-        macro_rules! try_in_poll {
-            ($expr:expr) => {{
-                match $expr {
-                    Ok(o) => o,
-                    // When using `AsyncWriteExt::write_all`, `io::ErrorKind::WriteZero` will be raised.
-                    // In this case it means "attempted to write on a closed socket".
-                    Err(WebSocketError::ConnectionClose(_)) => return Poll::Ready(Ok(0)),
-                    Err(e) => return Poll::Ready(Err(io::Error::new(io::ErrorKind::Other, e))),
-                }
-            }};
-        }
-
         // try flushing preemptively
         let _ = AsyncWrite::poll_flush(self.as_mut(), cx);
 
         // make sure sink is ready to send
-        try_in_poll!(ready!(self.as_mut().poll_ready(cx)));
+        try_in_poll_io!(ready!(self.as_mut().poll_ready(cx)));
 
         // actually submit new item
-        try_in_poll!(self.start_send(WebSocketMessage::Bytes(buf.to_vec())));
+        try_in_poll_io!(self.start_send(WebSocketMessage::Bytes(buf.to_vec())));
         // ^ if no error occurred, message is accepted and queued when calling `start_send`
         // (i.e.: `to_vec` is called only once)