From: Simon Tatham <anakin@pobox.com>
Date: Fri, 5 Jan 2024 22:55:13 +0000 (+0000)
Subject: Fix that horrible loop in the streaming subthread.
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=67b2627c0b5d67820b8e96043930aaf550d82330;p=mastodonochrome.git

Fix that horrible loop in the streaming subthread.

Clippy complained about it at fatal-error level because it never loops
more than once. I only wrote that loop so I could break it in multiple
places with different return values.

But I've had a better idea for how to write the fiddly bit, thanks to
remembering that Peekable is a thing. This is nicer.
---

diff --git a/src/client.rs b/src/client.rs
index e6700ea..a223af8 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -910,33 +910,35 @@ impl Client {
             while let Ok(sz) = rsp.read(&mut buf) {
                 let read = &buf[..sz];
                 vec.extend_from_slice(read);
-                vec = 'outer: loop {
-                    for line in vec.split_inclusive(|c| *c == 10) {
-                        if !line.ends_with(&[10]) {
-                            let mut newvec = Vec::new();
-                            newvec.extend_from_slice(line);
-                            break 'outer newvec;
-                        } else if line.starts_with(&[':' as u8]) {
-                            // Ignore lines starting with ':': in the
-                            // Mastodon streaming APIs those are
-                            // heartbeat events whose sole purpose is
-                            // to avoid the connection timing out. We
-                            // don't communicate them back to the main
-                            // thread.
-                        } else {
-                            let rsp = match std::str::from_utf8(&line) {
-                                Err(_) => StreamResponse::BadUTF8,
-                                Ok(d) => StreamResponse::Line(d.to_owned()),
-                            };
-                            receiver(StreamUpdate {
-                                id: id.clone(),
-                                response: rsp
-                            });
-                        }
+                let mut lines_iter = vec.split_inclusive(|c| *c == b'\n')
+                    .peekable();
+                while let Some(line) = lines_iter.next_if(
+                    |line| line.ends_with(b"\n"))
+                {
+                    if line.starts_with(b":") {
+                        // Ignore lines starting with ':': in the
+                        // Mastodon streaming APIs those are heartbeat
+                        // events whose sole purpose is to avoid the
+                        // connection timing out. We don't communicate
+                        // them back to the main thread.
+                    } else {
+                        let rsp = match std::str::from_utf8(&line) {
+                            Err(_) => StreamResponse::BadUTF8,
+                            Ok(d) => StreamResponse::Line(d.to_owned()),
+                        };
+                        receiver(StreamUpdate {
+                            id: id.clone(),
+                            response: rsp
+                        });
                     }
-                    // If we didn't get a partial line inside the loop, then
-                    // we must have an empty buffer here
-                    break Vec::new();
+                }
+
+                // We've consumed all the complete lines in the
+                // vector. Reinitialise the vector to whatever is
+                // left.
+                vec = match lines_iter.next() {
+                    Some(rest) => rest.into(),
+                    None => Vec::new(),
                 };
             }