feat(tui2): copy tui crate and normalize snapshots (#7833)

Introduce a full codex-tui source snapshot under the new codex-tui2
crate so viewport work can be replayed in isolation.

This change copies the entire codex-rs/tui/src tree into
codex-rs/tui2/src in one atomic step, rather than piecemeal, to keep
future diffs vs the original viewport bookmark easy to reason about.

The goal is for codex-tui2 to render identically to the existing TUI
behind the `features.tui2` flag while we gradually port the
viewport/history commits from the joshka/viewport bookmark onto this
forked tree.

While on this baseline change, we also ran the codex-tui2 snapshot test
suite and accepted all insta snapshots for the new crate, so the
snapshot files now use the codex-tui2 naming scheme and encode the
unmodified legacy TUI behavior. This keeps later viewport commits
focused on intentional behavior changes (and their snapshots) rather
than on mechanical snapshot renames.

codex-rs/tui2/src/tui.rs

@@ -0,0 +1,441 @@
+use std::fmt;
+use std::io::IsTerminal;
+use std::io::Result;
+use std::io::Stdout;
+use std::io::stdin;
+use std::io::stdout;
+use std::panic;
+use std::pin::Pin;
+use std::sync::Arc;
+use std::sync::atomic::AtomicBool;
+use std::sync::atomic::Ordering;
+
+use crossterm::Command;
+use crossterm::SynchronizedUpdate;
+use crossterm::event::DisableBracketedPaste;
+use crossterm::event::DisableFocusChange;
+use crossterm::event::EnableBracketedPaste;
+use crossterm::event::EnableFocusChange;
+use crossterm::event::Event;
+use crossterm::event::KeyEvent;
+use crossterm::event::KeyboardEnhancementFlags;
+use crossterm::event::PopKeyboardEnhancementFlags;
+use crossterm::event::PushKeyboardEnhancementFlags;
+use crossterm::terminal::EnterAlternateScreen;
+use crossterm::terminal::LeaveAlternateScreen;
+use crossterm::terminal::supports_keyboard_enhancement;
+use ratatui::backend::Backend;
+use ratatui::backend::CrosstermBackend;
+use ratatui::crossterm::execute;
+use ratatui::crossterm::terminal::disable_raw_mode;
+use ratatui::crossterm::terminal::enable_raw_mode;
+use ratatui::layout::Offset;
+use ratatui::layout::Rect;
+use ratatui::text::Line;
+use tokio::select;
+use tokio::sync::broadcast;
+use tokio_stream::Stream;
+
+pub use self::frame_requester::FrameRequester;
+use crate::custom_terminal;
+use crate::custom_terminal::Terminal as CustomTerminal;
+#[cfg(unix)]
+use crate::tui::job_control::SUSPEND_KEY;
+#[cfg(unix)]
+use crate::tui::job_control::SuspendContext;
+
+mod frame_requester;
+#[cfg(unix)]
+mod job_control;
+
+/// A type alias for the terminal type used in this application
+pub type Terminal = CustomTerminal<CrosstermBackend<Stdout>>;
+
+pub fn set_modes() -> Result<()> {
+    execute!(stdout(), EnableBracketedPaste)?;
+
+    enable_raw_mode()?;
+    // Enable keyboard enhancement flags so modifiers for keys like Enter are disambiguated.
+    // chat_composer.rs is using a keyboard event listener to enter for any modified keys
+    // to create a new line that require this.
+    // Some terminals (notably legacy Windows consoles) do not support
+    // keyboard enhancement flags. Attempt to enable them, but continue
+    // gracefully if unsupported.
+    let _ = execute!(
+        stdout(),
+        PushKeyboardEnhancementFlags(
+            KeyboardEnhancementFlags::DISAMBIGUATE_ESCAPE_CODES
+                | KeyboardEnhancementFlags::REPORT_EVENT_TYPES
+                | KeyboardEnhancementFlags::REPORT_ALTERNATE_KEYS
+        )
+    );
+
+    let _ = execute!(stdout(), EnableFocusChange);
+    Ok(())
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+struct EnableAlternateScroll;
+
+impl Command for EnableAlternateScroll {
+    fn write_ansi(&self, f: &mut impl fmt::Write) -> fmt::Result {
+        write!(f, "\x1b[?1007h")
+    }
+
+    #[cfg(windows)]
+    fn execute_winapi(&self) -> Result<()> {
+        Err(std::io::Error::other(
+            "tried to execute EnableAlternateScroll using WinAPI; use ANSI instead",
+        ))
+    }
+
+    #[cfg(windows)]
+    fn is_ansi_code_supported(&self) -> bool {
+        true
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+struct DisableAlternateScroll;
+
+impl Command for DisableAlternateScroll {
+    fn write_ansi(&self, f: &mut impl fmt::Write) -> fmt::Result {
+        write!(f, "\x1b[?1007l")
+    }
+
+    #[cfg(windows)]
+    fn execute_winapi(&self) -> Result<()> {
+        Err(std::io::Error::other(
+            "tried to execute DisableAlternateScroll using WinAPI; use ANSI instead",
+        ))
+    }
+
+    #[cfg(windows)]
+    fn is_ansi_code_supported(&self) -> bool {
+        true
+    }
+}
+
+/// Restore the terminal to its original state.
+/// Inverse of `set_modes`.
+pub fn restore() -> Result<()> {
+    // Pop may fail on platforms that didn't support the push; ignore errors.
+    let _ = execute!(stdout(), PopKeyboardEnhancementFlags);
+    execute!(stdout(), DisableBracketedPaste)?;
+    let _ = execute!(stdout(), DisableFocusChange);
+    disable_raw_mode()?;
+    let _ = execute!(stdout(), crossterm::cursor::Show);
+    Ok(())
+}
+
+/// Initialize the terminal (inline viewport; history stays in normal scrollback)
+pub fn init() -> Result<Terminal> {
+    if !stdin().is_terminal() {
+        return Err(std::io::Error::other("stdin is not a terminal"));
+    }
+    if !stdout().is_terminal() {
+        return Err(std::io::Error::other("stdout is not a terminal"));
+    }
+    set_modes()?;
+
+    set_panic_hook();
+
+    let backend = CrosstermBackend::new(stdout());
+    let tui = CustomTerminal::with_options(backend)?;
+    Ok(tui)
+}
+
+fn set_panic_hook() {
+    let hook = panic::take_hook();
+    panic::set_hook(Box::new(move |panic_info| {
+        let _ = restore(); // ignore any errors as we are already failing
+        hook(panic_info);
+    }));
+}
+
+#[derive(Debug)]
+pub enum TuiEvent {
+    Key(KeyEvent),
+    Paste(String),
+    Draw,
+}
+
+pub struct Tui {
+    frame_requester: FrameRequester,
+    draw_tx: broadcast::Sender<()>,
+    pub(crate) terminal: Terminal,
+    pending_history_lines: Vec<Line<'static>>,
+    alt_saved_viewport: Option<ratatui::layout::Rect>,
+    #[cfg(unix)]
+    suspend_context: SuspendContext,
+    // True when overlay alt-screen UI is active
+    alt_screen_active: Arc<AtomicBool>,
+    // True when terminal/tab is focused; updated internally from crossterm events
+    terminal_focused: Arc<AtomicBool>,
+    enhanced_keys_supported: bool,
+}
+
+impl Tui {
+    pub fn new(terminal: Terminal) -> Self {
+        let (draw_tx, _) = broadcast::channel(1);
+        let frame_requester = FrameRequester::new(draw_tx.clone());
+
+        // Detect keyboard enhancement support before any EventStream is created so the
+        // crossterm poller can acquire its lock without contention.
+        let enhanced_keys_supported = supports_keyboard_enhancement().unwrap_or(false);
+        // Cache this to avoid contention with the event reader.
+        supports_color::on_cached(supports_color::Stream::Stdout);
+        let _ = crate::terminal_palette::default_colors();
+
+        Self {
+            frame_requester,
+            draw_tx,
+            terminal,
+            pending_history_lines: vec![],
+            alt_saved_viewport: None,
+            #[cfg(unix)]
+            suspend_context: SuspendContext::new(),
+            alt_screen_active: Arc::new(AtomicBool::new(false)),
+            terminal_focused: Arc::new(AtomicBool::new(true)),
+            enhanced_keys_supported,
+        }
+    }
+
+    pub fn frame_requester(&self) -> FrameRequester {
+        self.frame_requester.clone()
+    }
+
+    pub fn enhanced_keys_supported(&self) -> bool {
+        self.enhanced_keys_supported
+    }
+
+    /// Emit a desktop notification now if the terminal is unfocused.
+    /// Returns true if a notification was posted.
+    pub fn notify(&mut self, message: impl AsRef<str>) -> bool {
+        if !self.terminal_focused.load(Ordering::Relaxed) {
+            let _ = execute!(stdout(), PostNotification(message.as_ref().to_string()));
+            true
+        } else {
+            false
+        }
+    }
+
+    pub fn event_stream(&self) -> Pin<Box<dyn Stream<Item = TuiEvent> + Send + 'static>> {
+        use tokio_stream::StreamExt;
+
+        let mut crossterm_events = crossterm::event::EventStream::new();
+        let mut draw_rx = self.draw_tx.subscribe();
+
+        // State for tracking how we should resume from ^Z suspend.
+        #[cfg(unix)]
+        let suspend_context = self.suspend_context.clone();
+        #[cfg(unix)]
+        let alt_screen_active = self.alt_screen_active.clone();
+
+        let terminal_focused = self.terminal_focused.clone();
+        let event_stream = async_stream::stream! {
+            loop {
+                select! {
+                    Some(Ok(event)) = crossterm_events.next() => {
+                        match event {
+                            Event::Key(key_event) => {
+                                #[cfg(unix)]
+                                if SUSPEND_KEY.is_press(key_event) {
+                                    let _ = suspend_context.suspend(&alt_screen_active);
+                                    // We continue here after resume.
+                                    yield TuiEvent::Draw;
+                                    continue;
+                                }
+                                yield TuiEvent::Key(key_event);
+                            }
+                            Event::Resize(_, _) => {
+                                yield TuiEvent::Draw;
+                            }
+                            Event::Paste(pasted) => {
+                                yield TuiEvent::Paste(pasted);
+                            }
+                            Event::FocusGained => {
+                                terminal_focused.store(true, Ordering::Relaxed);
+                                crate::terminal_palette::requery_default_colors();
+                                yield TuiEvent::Draw;
+                            }
+                            Event::FocusLost => {
+                                terminal_focused.store(false, Ordering::Relaxed);
+                            }
+                            _ => {}
+                        }
+                    }
+                    result = draw_rx.recv() => {
+                        match result {
+                            Ok(_) => {
+                                yield TuiEvent::Draw;
+                            }
+                            Err(tokio::sync::broadcast::error::RecvError::Lagged(_)) => {
+                                // We dropped one or more draw notifications; coalesce to a single draw.
+                                yield TuiEvent::Draw;
+                            }
+                            Err(tokio::sync::broadcast::error::RecvError::Closed) => {
+                                // Sender dropped; stop emitting draws from this source.
+                            }
+                        }
+                    }
+                }
+            }
+        };
+        Box::pin(event_stream)
+    }
+
+    /// Enter alternate screen and expand the viewport to full terminal size, saving the current
+    /// inline viewport for restoration when leaving.
+    pub fn enter_alt_screen(&mut self) -> Result<()> {
+        let _ = execute!(self.terminal.backend_mut(), EnterAlternateScreen);
+        // Enable "alternate scroll" so terminals may translate wheel to arrows
+        let _ = execute!(self.terminal.backend_mut(), EnableAlternateScroll);
+        if let Ok(size) = self.terminal.size() {
+            self.alt_saved_viewport = Some(self.terminal.viewport_area);
+            self.terminal.set_viewport_area(ratatui::layout::Rect::new(
+                0,
+                0,
+                size.width,
+                size.height,
+            ));
+            let _ = self.terminal.clear();
+        }
+        self.alt_screen_active.store(true, Ordering::Relaxed);
+        Ok(())
+    }
+
+    /// Leave alternate screen and restore the previously saved inline viewport, if any.
+    pub fn leave_alt_screen(&mut self) -> Result<()> {
+        // Disable alternate scroll when leaving alt-screen
+        let _ = execute!(self.terminal.backend_mut(), DisableAlternateScroll);
+        let _ = execute!(self.terminal.backend_mut(), LeaveAlternateScreen);
+        if let Some(saved) = self.alt_saved_viewport.take() {
+            self.terminal.set_viewport_area(saved);
+        }
+        self.alt_screen_active.store(false, Ordering::Relaxed);
+        Ok(())
+    }
+
+    pub fn insert_history_lines(&mut self, lines: Vec<Line<'static>>) {
+        self.pending_history_lines.extend(lines);
+        self.frame_requester().schedule_frame();
+    }
+
+    pub fn draw(
+        &mut self,
+        height: u16,
+        draw_fn: impl FnOnce(&mut custom_terminal::Frame),
+    ) -> Result<()> {
+        // If we are resuming from ^Z, we need to prepare the resume action now so we can apply it
+        // in the synchronized update.
+        #[cfg(unix)]
+        let mut prepared_resume = self
+            .suspend_context
+            .prepare_resume_action(&mut self.terminal, &mut self.alt_saved_viewport);
+
+        // Precompute any viewport updates that need a cursor-position query before entering
+        // the synchronized update, to avoid racing with the event reader.
+        let mut pending_viewport_area = self.pending_viewport_area()?;
+
+        stdout().sync_update(|_| {
+            #[cfg(unix)]
+            if let Some(prepared) = prepared_resume.take() {
+                prepared.apply(&mut self.terminal)?;
+            }
+
+            let terminal = &mut self.terminal;
+            if let Some(new_area) = pending_viewport_area.take() {
+                terminal.set_viewport_area(new_area);
+                terminal.clear()?;
+            }
+
+            let size = terminal.size()?;
+
+            let mut area = terminal.viewport_area;
+            area.height = height.min(size.height);
+            area.width = size.width;
+            // If the viewport has expanded, scroll everything else up to make room.
+            if area.bottom() > size.height {
+                terminal
+                    .backend_mut()
+                    .scroll_region_up(0..area.top(), area.bottom() - size.height)?;
+                area.y = size.height - area.height;
+            }
+            if area != terminal.viewport_area {
+                // TODO(nornagon): probably this could be collapsed with the clear + set_viewport_area above.
+                terminal.clear()?;
+                terminal.set_viewport_area(area);
+            }
+
+            if !self.pending_history_lines.is_empty() {
+                crate::insert_history::insert_history_lines(
+                    terminal,
+                    self.pending_history_lines.clone(),
+                )?;
+                self.pending_history_lines.clear();
+            }
+
+            // Update the y position for suspending so Ctrl-Z can place the cursor correctly.
+            #[cfg(unix)]
+            {
+                let inline_area_bottom = if self.alt_screen_active.load(Ordering::Relaxed) {
+                    self.alt_saved_viewport
+                        .map(|r| r.bottom().saturating_sub(1))
+                        .unwrap_or_else(|| area.bottom().saturating_sub(1))
+                } else {
+                    area.bottom().saturating_sub(1)
+                };
+                self.suspend_context.set_cursor_y(inline_area_bottom);
+            }
+
+            terminal.draw(|frame| {
+                draw_fn(frame);
+            })
+        })?
+    }
+
+    fn pending_viewport_area(&mut self) -> Result<Option<Rect>> {
+        let terminal = &mut self.terminal;
+        let screen_size = terminal.size()?;
+        let last_known_screen_size = terminal.last_known_screen_size;
+        if screen_size != last_known_screen_size
+            && let Ok(cursor_pos) = terminal.get_cursor_position()
+        {
+            let last_known_cursor_pos = terminal.last_known_cursor_pos;
+            // If we resized AND the cursor moved, we adjust the viewport area to keep the
+            // cursor in the same position. This is a heuristic that seems to work well
+            // at least in iTerm2.
+            if cursor_pos.y != last_known_cursor_pos.y {
+                let offset = Offset {
+                    x: 0,
+                    y: cursor_pos.y as i32 - last_known_cursor_pos.y as i32,
+                };
+                return Ok(Some(terminal.viewport_area.offset(offset)));
+            }
+        }
+        Ok(None)
+    }
+}
+
+/// Command that emits an OSC 9 desktop notification with a message.
+#[derive(Debug, Clone)]
+pub struct PostNotification(pub String);
+
+impl Command for PostNotification {
+    fn write_ansi(&self, f: &mut impl fmt::Write) -> fmt::Result {
+        write!(f, "\x1b]9;{}\x07", self.0)
+    }
+
+    #[cfg(windows)]
+    fn execute_winapi(&self) -> Result<()> {
+        Err(std::io::Error::other(
+            "tried to execute PostNotification using WinAPI; use ANSI instead",
+        ))
+    }
+
+    #[cfg(windows)]
+    fn is_ansi_code_supported(&self) -> bool {
+        true
+    }
+}