Re-add markdown streaming (#2029)

Wait for newlines, then render markdown on a line by line basis. Word wrap it for the current terminal size and then spit it out line by line into the UI. Also adds tests and fixes some UI regressions.

codex-rs/tui/src/app.rs

@@ -31,7 +31,7 @@ use std::thread;
 use std::time::Duration;
 
 /// Time window for debouncing redraw requests.
-const REDRAW_DEBOUNCE: Duration = Duration::from_millis(10);
+const REDRAW_DEBOUNCE: Duration = Duration::from_millis(1);
 
 /// Top-level application state: which full-screen view is currently active.
 #[allow(clippy::large_enum_variant)]
@@ -63,6 +63,9 @@ pub(crate) struct App<'a> {
     pending_history_lines: Vec<Line<'static>>,
 
     enhanced_keys_supported: bool,
+
+    /// Controls the animation thread that sends CommitTick events.
+    commit_anim_running: Arc<AtomicBool>,
 }
 
 /// Aggregate parameters needed to create a `ChatWidget`, as creation may be
@@ -110,10 +113,8 @@ impl App<'_> {
                                     app_event_tx.send(AppEvent::RequestRedraw);
                                 }
                                 crossterm::event::Event::Paste(pasted) => {
-                                    // Many terminals convert newlines to \r when
-                                    // pasting, e.g. [iTerm2][]. But [tui-textarea
-                                    // expects \n][tui-textarea]. This seems like a bug
-                                    // in tui-textarea IMO, but work around it for now.
+                                    // Many terminals convert newlines to \r when pasting (e.g., iTerm2),
+                                    // but tui-textarea expects \n. Normalize CR to LF.
                                     // [tui-textarea]: https://github.com/rhysd/tui-textarea/blob/4d18622eeac13b309e0ff6a55a46ac6706da68cf/src/textarea.rs#L782-L783
                                     // [iTerm2]: https://github.com/gnachman/iTerm2/blob/5d0c0d9f68523cbd0494dad5422998964a2ecd8d/sources/iTermPasteHelper.m#L206-L216
                                     let pasted = pasted.replace("\r", "\n");
@@ -172,6 +173,7 @@ impl App<'_> {
             file_search,
             pending_redraw,
             enhanced_keys_supported,
+            commit_anim_running: Arc::new(AtomicBool::new(false)),
         }
     }
 
@@ -188,7 +190,7 @@ impl App<'_> {
         // redraw is already pending so we can return early.
         if self
             .pending_redraw
-            .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst)
+            .compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
             .is_err()
         {
             return;
@@ -199,7 +201,7 @@ impl App<'_> {
         thread::spawn(move || {
             thread::sleep(REDRAW_DEBOUNCE);
             tx.send(AppEvent::Redraw);
-            pending_redraw.store(false, Ordering::SeqCst);
+            pending_redraw.store(false, Ordering::Release);
         });
     }
 
@@ -220,6 +222,30 @@ impl App<'_> {
                 AppEvent::Redraw => {
                     std::io::stdout().sync_update(|_| self.draw_next_frame(terminal))??;
                 }
+                AppEvent::StartCommitAnimation => {
+                    if self
+                        .commit_anim_running
+                        .compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
+                        .is_ok()
+                    {
+                        let tx = self.app_event_tx.clone();
+                        let running = self.commit_anim_running.clone();
+                        thread::spawn(move || {
+                            while running.load(Ordering::Relaxed) {
+                                thread::sleep(Duration::from_millis(50));
+                                tx.send(AppEvent::CommitTick);
+                            }
+                        });
+                    }
+                }
+                AppEvent::StopCommitAnimation => {
+                    self.commit_anim_running.store(false, Ordering::Release);
+                }
+                AppEvent::CommitTick => {
+                    if let AppState::Chat { widget } = &mut self.app_state {
+                        widget.on_commit_tick();
+                    }
+                }
                 AppEvent::KeyEvent(key_event) => {
                     match key_event {
                         KeyEvent {
@@ -276,7 +302,7 @@ impl App<'_> {
                             self.dispatch_key_event(key_event);
                         }
                         _ => {
-                            // Ignore Release key events for now.
+                            // Ignore Release key events.
                         }
                     };
                 }