Function spawn_sync_server

atomic-cli/tests/clone_sidecar_integration_test.rs:125–173

Serve the `/code` sync protocol: any GET whose path ends in `/code` gets the canned `SyncPack`; everything else is a 404. One request per connection (`Connection: close`), which is all reqwest needs.

(pack: SyncPack)

/// the canned `SyncPack`; everything else is a 404. One request per
/// connection (`Connection: close`), which is all reqwest needs.
fn spawn_sync_server(pack: SyncPack) -> String {
    let listener = TcpListener::bind("127.0.0.1:0").expect("bind test server");
    let addr = listener.local_addr().expect("local addr");
    let pack_bytes = pack.encode().expect("encode sync pack");

    std::thread::spawn(move || {
        for stream in listener.incoming().flatten() {
            let mut stream = stream;
            let mut buf = Vec::new();
            let mut tmp = [0u8; 4096];
            // Read the request head + body (Content-Length bounded).
            loop {
                let n = match stream.read(&mut tmp) {
                    Ok(0) | Err(_) => break,
                    Ok(n) => n,
                };
                buf.extend_from_slice(&tmp[..n]);
                if let Some(head_end) = find_head_end(&buf) {
                    let head = String::from_utf8_lossy(&buf[..head_end]).to_string();
                    if let Some(len) = content_length(&head) {
                        if buf.len() >= head_end + 4 + len {
                            break;
                        }
                    } else {
                        break;
                    }
                }
            }
            let head = String::from_utf8_lossy(&buf).to_string();
            let path = head.split_whitespace().nth(1).unwrap_or("");

            let (status, body) = if path.ends_with("/code") {
                ("200 OK", pack_bytes.clone())
            } else {
                ("404 Not Found", b"not found".to_vec())
            };
            let response = format!(
                "HTTP/1.1 {status}\r\nContent-Type: application/octet-stream\r\n\
                 X-Atomic-Min-Version: 0.16.2\r\nContent-Length: {}\r\nConnection: close\r\n\r\n",
                body.len()
            );
            let _ = stream.write_all(response.as_bytes());
            let _ = stream.write_all(&body);
            let _ = stream.flush();
        }
    });

    format!("http://{}", addr)
}

fn find_head_end(buf: &[u8]) -> Option<usize> {
    buf.windows(4).position(|w| w == b"\r\n\r\n")