Preserve alternate screen snapshots and speed builds

Cargo.toml

@@ -27,6 +27,8 @@ vt100 = "0.15"
 tempfile = "3.14"
 
 [profile.release]
-codegen-units = 1
-lto = "thin"
-strip = true
+opt-level = 2
+codegen-units = 16
+incremental = true
+lto = false
+strip = false

src/bin/dosh-server.rs

@@ -277,7 +277,7 @@ async fn handle_bootstrap_attach(
             session.parser.set_size(req.rows, req.cols);
         }
         let client_id = crypto::random_16();
-        let snapshot = session.parser.screen().state_formatted();
+        let snapshot = screen_snapshot(session.parser.screen());
         let screen = session.parser.screen().clone();
         let output_seq = session.output_seq;
         session.clients.insert(
@@ -385,7 +385,7 @@ async fn handle_ticket_attach(
             session.parser.set_size(req.rows, req.cols);
         }
         let client_id = crypto::random_16();
-        let snapshot = session.parser.screen().state_formatted();
+        let snapshot = screen_snapshot(session.parser.screen());
         let screen = session.parser.screen().clone();
         let output_seq = session.output_seq;
         session.clients.insert(
@@ -491,7 +491,7 @@ async fn handle_resume(
             session.pty.resize(req.cols, req.rows)?;
             session.parser.set_size(req.rows, req.cols);
         }
-        let snapshot = session.parser.screen().state_formatted();
+        let snapshot = screen_snapshot(session.parser.screen());
         client.last_screen = Some(session.parser.screen().clone());
         (client.send_seq, session.output_seq, snapshot)
     };
@@ -675,7 +675,7 @@ async fn broadcast_output(
             let current_screen = session.parser.screen().clone();
             let (bytes, snapshot) = if client.pending.len() >= retransmit_window {
                 client.pending.clear();
-                (current_screen.state_formatted(), true)
+                (screen_snapshot(&current_screen), true)
             } else {
                 (output.bytes.clone(), false)
             };
@@ -758,6 +758,17 @@ async fn broadcast_session_exit(
     Ok(())
 }
 
+fn screen_snapshot(screen: &vt100::Screen) -> Vec<u8> {
+    let mut bytes = Vec::new();
+    if screen.alternate_screen() {
+        bytes.extend_from_slice(b"\x1b[?1049h");
+    } else {
+        bytes.extend_from_slice(b"\x1b[?1049l");
+    }
+    bytes.extend(screen.state_formatted());
+    bytes
+}
+
 async fn retransmit_pending(
     state: &Arc<Mutex<ServerState>>,
     socket: &Arc<UdpSocket>,

tests/integration_smoke.rs

@@ -572,6 +572,63 @@ fn live_output_forwards_terminal_control_sequences() {
     );
 }
 
+#[test]
+fn resume_snapshot_preserves_alternate_screen_mode() {
+    let dir = tempfile::tempdir().unwrap();
+    let port = free_udp_port();
+    let config = write_server_config(&dir, port);
+    let mut server = start_server(&dir, &config);
+    let (socket, bootstrap, ok) = direct_attach(&config, port, "read-write");
+
+    let input = Input {
+        bytes: b"printf '\\033[?1049hALT_SNAPSHOT'\n".to_vec(),
+    };
+    send_encrypted(
+        &socket,
+        port,
+        PacketKind::Input,
+        ok.client_id,
+        2,
+        0,
+        &bootstrap.session_key,
+        &protocol::to_body(&input).unwrap(),
+    );
+    let _ = collect_frame_text(&socket, &bootstrap.session_key, 500);
+    let new_socket = UdpSocket::bind("127.0.0.1:0").unwrap();
+    new_socket
+        .set_read_timeout(Some(Duration::from_secs(2)))
+        .unwrap();
+
+    let resume = ResumeRequest {
+        session: "default".to_string(),
+        last_rendered_seq: ok.initial_seq,
+        cols: 80,
+        rows: 24,
+    };
+    send_encrypted(
+        &new_socket,
+        port,
+        PacketKind::ResumeRequest,
+        ok.client_id,
+        3,
+        0,
+        &bootstrap.session_key,
+        &protocol::to_body(&resume).unwrap(),
+    );
+    let (_header, resume_frame) =
+        recv_frame(&new_socket, &bootstrap.session_key).expect("resume response");
+
+    let _ = server.kill();
+    let _ = server.wait();
+
+    assert!(resume_frame.snapshot);
+    assert!(
+        resume_frame.bytes.starts_with(b"\x1b[?1049h"),
+        "snapshot did not enter alternate screen first: {:?}",
+        String::from_utf8_lossy(&resume_frame.bytes)
+    );
+}
+
 #[test]
 fn resume_updates_udp_endpoint_for_roaming() {
     let dir = tempfile::tempdir().unwrap();