app.rs

   1use scheduler::Instant;
   2use std::{
   3    any::{TypeId, type_name},
   4    cell::{BorrowMutError, Cell, Ref, RefCell, RefMut},
   5    marker::PhantomData,
   6    mem,
   7    ops::{Deref, DerefMut},
   8    path::{Path, PathBuf},
   9    rc::{Rc, Weak},
  10    sync::{Arc, atomic::Ordering::SeqCst},
  11    time::Duration,
  12};
  13
  14use anyhow::{Context as _, Result, anyhow};
  15use derive_more::{Deref, DerefMut};
  16use futures::{
  17    Future, FutureExt,
  18    channel::oneshot,
  19    future::{LocalBoxFuture, Shared},
  20};
  21use itertools::Itertools;
  22use parking_lot::RwLock;
  23use slotmap::SlotMap;
  24
  25pub use async_context::*;
  26use collections::{FxHashMap, FxHashSet, HashMap, VecDeque};
  27pub use context::*;
  28pub use entity_map::*;
  29use gpui_util::{ResultExt, debug_panic};
  30use http_client::{HttpClient, Url};
  31use smallvec::SmallVec;
  32#[cfg(any(test, feature = "test-support"))]
  33pub use test_context::*;
  34#[cfg(all(target_os = "macos", any(test, feature = "test-support")))]
  35pub use visual_test_context::*;
  36
  37#[cfg(any(feature = "inspector", debug_assertions))]
  38use crate::InspectorElementRegistry;
  39use crate::{
  40    Action, ActionBuildError, ActionRegistry, Any, AnyView, AnyWindowHandle, AppContext, Arena,
  41    ArenaBox, Asset, AssetSource, BackgroundExecutor, Bounds, ClipboardItem, CursorStyle,
  42    DispatchPhase, DisplayId, EventEmitter, FocusHandle, FocusMap, ForegroundExecutor, Global,
  43    KeyBinding, KeyContext, Keymap, Keystroke, LayoutId, Menu, MenuItem, OwnedMenu,
  44    PathPromptOptions, Pixels, Platform, PlatformDisplay, PlatformKeyboardLayout,
  45    PlatformKeyboardMapper, Point, Priority, PromptBuilder, PromptButton, PromptHandle,
  46    PromptLevel, Render, RenderImage, RenderablePromptHandle, Reservation, ScreenCaptureSource,
  47    SharedString, SubscriberSet, Subscription, SvgRenderer, Task, TextRenderingMode, TextSystem,
  48    ThermalState, Window, WindowAppearance, WindowHandle, WindowId, WindowInvalidator,
  49    colors::{Colors, GlobalColors},
  50    hash, init_app_menus,
  51};
  52
  53mod async_context;
  54mod context;
  55mod entity_map;
  56#[cfg(any(test, feature = "test-support"))]
  57mod test_context;
  58#[cfg(all(target_os = "macos", any(test, feature = "test-support")))]
  59mod visual_test_context;
  60
  61/// The duration for which futures returned from [Context::on_app_quit] can run before the application fully quits.
  62pub const SHUTDOWN_TIMEOUT: Duration = Duration::from_millis(100);
  63
  64/// Temporary(?) wrapper around [`RefCell<App>`] to help us debug any double borrows.
  65/// Strongly consider removing after stabilization.
  66#[doc(hidden)]
  67pub struct AppCell {
  68    app: RefCell<App>,
  69}
  70
  71impl AppCell {
  72    #[doc(hidden)]
  73    #[track_caller]
  74    pub fn borrow(&self) -> AppRef<'_> {
  75        if option_env!("TRACK_THREAD_BORROWS").is_some() {
  76            let thread_id = std::thread::current().id();
  77            eprintln!("borrowed {thread_id:?}");
  78        }
  79        AppRef(self.app.borrow())
  80    }
  81
  82    #[doc(hidden)]
  83    #[track_caller]
  84    pub fn borrow_mut(&self) -> AppRefMut<'_> {
  85        if option_env!("TRACK_THREAD_BORROWS").is_some() {
  86            let thread_id = std::thread::current().id();
  87            eprintln!("borrowed {thread_id:?}");
  88        }
  89        AppRefMut(self.app.borrow_mut())
  90    }
  91
  92    #[doc(hidden)]
  93    #[track_caller]
  94    pub fn try_borrow_mut(&self) -> Result<AppRefMut<'_>, BorrowMutError> {
  95        if option_env!("TRACK_THREAD_BORROWS").is_some() {
  96            let thread_id = std::thread::current().id();
  97            eprintln!("borrowed {thread_id:?}");
  98        }
  99        Ok(AppRefMut(self.app.try_borrow_mut()?))
 100    }
 101}
 102
 103#[doc(hidden)]
 104#[derive(Deref, DerefMut)]
 105pub struct AppRef<'a>(Ref<'a, App>);
 106
 107impl Drop for AppRef<'_> {
 108    fn drop(&mut self) {
 109        if option_env!("TRACK_THREAD_BORROWS").is_some() {
 110            let thread_id = std::thread::current().id();
 111            eprintln!("dropped borrow from {thread_id:?}");
 112        }
 113    }
 114}
 115
 116#[doc(hidden)]
 117#[derive(Deref, DerefMut)]
 118pub struct AppRefMut<'a>(RefMut<'a, App>);
 119
 120impl Drop for AppRefMut<'_> {
 121    fn drop(&mut self) {
 122        if option_env!("TRACK_THREAD_BORROWS").is_some() {
 123            let thread_id = std::thread::current().id();
 124            eprintln!("dropped {thread_id:?}");
 125        }
 126    }
 127}
 128
 129/// A reference to a GPUI application, typically constructed in the `main` function of your app.
 130/// You won't interact with this type much outside of initial configuration and startup.
 131pub struct Application(Rc<AppCell>);
 132
 133/// Represents an application before it is fully launched. Once your app is
 134/// configured, you'll start the app with `App::run`.
 135impl Application {
 136    /// Builds an app with a caller-provided platform implementation.
 137    pub fn with_platform(platform: Rc<dyn Platform>) -> Self {
 138        Self(App::new_app(
 139            platform,
 140            Arc::new(()),
 141            Arc::new(NullHttpClient),
 142        ))
 143    }
 144
 145    /// Assigns the source of assets for the application.
 146    pub fn with_assets(self, asset_source: impl AssetSource) -> Self {
 147        let mut context_lock = self.0.borrow_mut();
 148        let asset_source = Arc::new(asset_source);
 149        context_lock.asset_source = asset_source.clone();
 150        context_lock.svg_renderer = SvgRenderer::new(asset_source);
 151        drop(context_lock);
 152        self
 153    }
 154
 155    /// Sets the HTTP client for the application.
 156    pub fn with_http_client(self, http_client: Arc<dyn HttpClient>) -> Self {
 157        let mut context_lock = self.0.borrow_mut();
 158        context_lock.http_client = http_client;
 159        drop(context_lock);
 160        self
 161    }
 162
 163    /// Configures when the application should automatically quit.
 164    /// By default, [`QuitMode::Default`] is used.
 165    pub fn with_quit_mode(self, mode: QuitMode) -> Self {
 166        self.0.borrow_mut().quit_mode = mode;
 167        self
 168    }
 169
 170    /// Start the application. The provided callback will be called once the
 171    /// app is fully launched.
 172    pub fn run<F>(self, on_finish_launching: F)
 173    where
 174        F: 'static + FnOnce(&mut App),
 175    {
 176        let this = self.0.clone();
 177        let platform = self.0.borrow().platform.clone();
 178        platform.run(Box::new(move || {
 179            let cx = &mut *this.borrow_mut();
 180            on_finish_launching(cx);
 181        }));
 182    }
 183
 184    /// Register a handler to be invoked when the platform instructs the application
 185    /// to open one or more URLs.
 186    pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
 187    where
 188        F: 'static + FnMut(Vec<String>),
 189    {
 190        self.0.borrow().platform.on_open_urls(Box::new(callback));
 191        self
 192    }
 193
 194    /// Invokes a handler when an already-running application is launched.
 195    /// On macOS, this can occur when the application icon is double-clicked or the app is launched via the dock.
 196    pub fn on_reopen<F>(&self, mut callback: F) -> &Self
 197    where
 198        F: 'static + FnMut(&mut App),
 199    {
 200        let this = Rc::downgrade(&self.0);
 201        self.0.borrow_mut().platform.on_reopen(Box::new(move || {
 202            if let Some(app) = this.upgrade() {
 203                callback(&mut app.borrow_mut());
 204            }
 205        }));
 206        self
 207    }
 208
 209    /// Returns a handle to the [`BackgroundExecutor`] associated with this app, which can be used to spawn futures in the background.
 210    pub fn background_executor(&self) -> BackgroundExecutor {
 211        self.0.borrow().background_executor.clone()
 212    }
 213
 214    /// Returns a handle to the [`ForegroundExecutor`] associated with this app, which can be used to spawn futures in the foreground.
 215    pub fn foreground_executor(&self) -> ForegroundExecutor {
 216        self.0.borrow().foreground_executor.clone()
 217    }
 218
 219    /// Returns a reference to the [`TextSystem`] associated with this app.
 220    pub fn text_system(&self) -> Arc<TextSystem> {
 221        self.0.borrow().text_system.clone()
 222    }
 223
 224    /// Returns the file URL of the executable with the specified name in the application bundle
 225    pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
 226        self.0.borrow().path_for_auxiliary_executable(name)
 227    }
 228}
 229
 230type Handler = Box<dyn FnMut(&mut App) -> bool + 'static>;
 231type Listener = Box<dyn FnMut(&dyn Any, &mut App) -> bool + 'static>;
 232pub(crate) type KeystrokeObserver =
 233    Box<dyn FnMut(&KeystrokeEvent, &mut Window, &mut App) -> bool + 'static>;
 234type QuitHandler = Box<dyn FnOnce(&mut App) -> LocalBoxFuture<'static, ()> + 'static>;
 235type WindowClosedHandler = Box<dyn FnMut(&mut App)>;
 236type ReleaseListener = Box<dyn FnOnce(&mut dyn Any, &mut App) + 'static>;
 237type NewEntityListener = Box<dyn FnMut(AnyEntity, &mut Option<&mut Window>, &mut App) + 'static>;
 238
 239/// Defines when the application should automatically quit.
 240#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
 241pub enum QuitMode {
 242    /// Use [`QuitMode::Explicit`] on macOS and [`QuitMode::LastWindowClosed`] on other platforms.
 243    #[default]
 244    Default,
 245    /// Quit automatically when the last window is closed.
 246    LastWindowClosed,
 247    /// Quit only when requested via [`App::quit`].
 248    Explicit,
 249}
 250
 251#[doc(hidden)]
 252#[derive(Clone, PartialEq, Eq)]
 253pub struct SystemWindowTab {
 254    pub id: WindowId,
 255    pub title: SharedString,
 256    pub handle: AnyWindowHandle,
 257    pub last_active_at: Instant,
 258}
 259
 260impl SystemWindowTab {
 261    /// Create a new instance of the window tab.
 262    pub fn new(title: SharedString, handle: AnyWindowHandle) -> Self {
 263        Self {
 264            id: handle.id,
 265            title,
 266            handle,
 267            last_active_at: Instant::now(),
 268        }
 269    }
 270}
 271
 272/// A controller for managing window tabs.
 273#[derive(Default)]
 274pub struct SystemWindowTabController {
 275    visible: Option<bool>,
 276    tab_groups: FxHashMap<usize, Vec<SystemWindowTab>>,
 277}
 278
 279impl Global for SystemWindowTabController {}
 280
 281impl SystemWindowTabController {
 282    /// Create a new instance of the window tab controller.
 283    pub fn new() -> Self {
 284        Self {
 285            visible: None,
 286            tab_groups: FxHashMap::default(),
 287        }
 288    }
 289
 290    /// Initialize the global window tab controller.
 291    pub fn init(cx: &mut App) {
 292        cx.set_global(SystemWindowTabController::new());
 293    }
 294
 295    /// Get all tab groups.
 296    pub fn tab_groups(&self) -> &FxHashMap<usize, Vec<SystemWindowTab>> {
 297        &self.tab_groups
 298    }
 299
 300    /// Get the next tab group window handle.
 301    pub fn get_next_tab_group_window(cx: &mut App, id: WindowId) -> Option<&AnyWindowHandle> {
 302        let controller = cx.global::<SystemWindowTabController>();
 303        let current_group = controller
 304            .tab_groups
 305            .iter()
 306            .find_map(|(group, tabs)| tabs.iter().find(|tab| tab.id == id).map(|_| group));
 307
 308        let current_group = current_group?;
 309        // TODO: `.keys()` returns arbitrary order, what does "next" mean?
 310        let mut group_ids: Vec<_> = controller.tab_groups.keys().collect();
 311        let idx = group_ids.iter().position(|g| *g == current_group)?;
 312        let next_idx = (idx + 1) % group_ids.len();
 313
 314        controller
 315            .tab_groups
 316            .get(group_ids[next_idx])
 317            .and_then(|tabs| {
 318                tabs.iter()
 319                    .max_by_key(|tab| tab.last_active_at)
 320                    .or_else(|| tabs.first())
 321                    .map(|tab| &tab.handle)
 322            })
 323    }
 324
 325    /// Get the previous tab group window handle.
 326    pub fn get_prev_tab_group_window(cx: &mut App, id: WindowId) -> Option<&AnyWindowHandle> {
 327        let controller = cx.global::<SystemWindowTabController>();
 328        let current_group = controller
 329            .tab_groups
 330            .iter()
 331            .find_map(|(group, tabs)| tabs.iter().find(|tab| tab.id == id).map(|_| group));
 332
 333        let current_group = current_group?;
 334        // TODO: `.keys()` returns arbitrary order, what does "previous" mean?
 335        let mut group_ids: Vec<_> = controller.tab_groups.keys().collect();
 336        let idx = group_ids.iter().position(|g| *g == current_group)?;
 337        let prev_idx = if idx == 0 {
 338            group_ids.len() - 1
 339        } else {
 340            idx - 1
 341        };
 342
 343        controller
 344            .tab_groups
 345            .get(group_ids[prev_idx])
 346            .and_then(|tabs| {
 347                tabs.iter()
 348                    .max_by_key(|tab| tab.last_active_at)
 349                    .or_else(|| tabs.first())
 350                    .map(|tab| &tab.handle)
 351            })
 352    }
 353
 354    /// Get all tabs in the same window.
 355    pub fn tabs(&self, id: WindowId) -> Option<&Vec<SystemWindowTab>> {
 356        self.tab_groups
 357            .values()
 358            .find(|tabs| tabs.iter().any(|tab| tab.id == id))
 359    }
 360
 361    /// Initialize the visibility of the system window tab controller.
 362    pub fn init_visible(cx: &mut App, visible: bool) {
 363        let mut controller = cx.global_mut::<SystemWindowTabController>();
 364        if controller.visible.is_none() {
 365            controller.visible = Some(visible);
 366        }
 367    }
 368
 369    /// Get the visibility of the system window tab controller.
 370    pub fn is_visible(&self) -> bool {
 371        self.visible.unwrap_or(false)
 372    }
 373
 374    /// Set the visibility of the system window tab controller.
 375    pub fn set_visible(cx: &mut App, visible: bool) {
 376        let mut controller = cx.global_mut::<SystemWindowTabController>();
 377        controller.visible = Some(visible);
 378    }
 379
 380    /// Update the last active of a window.
 381    pub fn update_last_active(cx: &mut App, id: WindowId) {
 382        let mut controller = cx.global_mut::<SystemWindowTabController>();
 383        for windows in controller.tab_groups.values_mut() {
 384            for tab in windows.iter_mut() {
 385                if tab.id == id {
 386                    tab.last_active_at = Instant::now();
 387                }
 388            }
 389        }
 390    }
 391
 392    /// Update the position of a tab within its group.
 393    pub fn update_tab_position(cx: &mut App, id: WindowId, ix: usize) {
 394        let mut controller = cx.global_mut::<SystemWindowTabController>();
 395        for (_, windows) in controller.tab_groups.iter_mut() {
 396            if let Some(current_pos) = windows.iter().position(|tab| tab.id == id) {
 397                if ix < windows.len() && current_pos != ix {
 398                    let window_tab = windows.remove(current_pos);
 399                    windows.insert(ix, window_tab);
 400                }
 401                break;
 402            }
 403        }
 404    }
 405
 406    /// Update the title of a tab.
 407    pub fn update_tab_title(cx: &mut App, id: WindowId, title: SharedString) {
 408        let controller = cx.global::<SystemWindowTabController>();
 409        let tab = controller
 410            .tab_groups
 411            .values()
 412            .flat_map(|windows| windows.iter())
 413            .find(|tab| tab.id == id);
 414
 415        if tab.map_or(true, |t| t.title == title) {
 416            return;
 417        }
 418
 419        let mut controller = cx.global_mut::<SystemWindowTabController>();
 420        for windows in controller.tab_groups.values_mut() {
 421            for tab in windows.iter_mut() {
 422                if tab.id == id {
 423                    tab.title = title;
 424                    return;
 425                }
 426            }
 427        }
 428    }
 429
 430    /// Insert a tab into a tab group.
 431    pub fn add_tab(cx: &mut App, id: WindowId, tabs: Vec<SystemWindowTab>) {
 432        let mut controller = cx.global_mut::<SystemWindowTabController>();
 433        let Some(tab) = tabs.iter().find(|tab| tab.id == id).cloned() else {
 434            return;
 435        };
 436
 437        let mut expected_tab_ids: Vec<_> = tabs
 438            .iter()
 439            .filter(|tab| tab.id != id)
 440            .map(|tab| tab.id)
 441            .sorted()
 442            .collect();
 443
 444        let mut tab_group_id = None;
 445        for (group_id, group_tabs) in &controller.tab_groups {
 446            let tab_ids: Vec<_> = group_tabs.iter().map(|tab| tab.id).sorted().collect();
 447            if tab_ids == expected_tab_ids {
 448                tab_group_id = Some(*group_id);
 449                break;
 450            }
 451        }
 452
 453        if let Some(tab_group_id) = tab_group_id {
 454            if let Some(tabs) = controller.tab_groups.get_mut(&tab_group_id) {
 455                tabs.push(tab);
 456            }
 457        } else {
 458            let new_group_id = controller.tab_groups.len();
 459            controller.tab_groups.insert(new_group_id, tabs);
 460        }
 461    }
 462
 463    /// Remove a tab from a tab group.
 464    pub fn remove_tab(cx: &mut App, id: WindowId) -> Option<SystemWindowTab> {
 465        let mut controller = cx.global_mut::<SystemWindowTabController>();
 466        let mut removed_tab = None;
 467
 468        controller.tab_groups.retain(|_, tabs| {
 469            if let Some(pos) = tabs.iter().position(|tab| tab.id == id) {
 470                removed_tab = Some(tabs.remove(pos));
 471            }
 472            !tabs.is_empty()
 473        });
 474
 475        removed_tab
 476    }
 477
 478    /// Move a tab to a new tab group.
 479    pub fn move_tab_to_new_window(cx: &mut App, id: WindowId) {
 480        let mut removed_tab = Self::remove_tab(cx, id);
 481        let mut controller = cx.global_mut::<SystemWindowTabController>();
 482
 483        if let Some(tab) = removed_tab {
 484            let new_group_id = controller.tab_groups.keys().max().map_or(0, |k| k + 1);
 485            controller.tab_groups.insert(new_group_id, vec![tab]);
 486        }
 487    }
 488
 489    /// Merge all tab groups into a single group.
 490    pub fn merge_all_windows(cx: &mut App, id: WindowId) {
 491        let mut controller = cx.global_mut::<SystemWindowTabController>();
 492        let Some(initial_tabs) = controller.tabs(id) else {
 493            return;
 494        };
 495
 496        let initial_tabs_len = initial_tabs.len();
 497        let mut all_tabs = initial_tabs.clone();
 498
 499        for (_, mut tabs) in controller.tab_groups.drain() {
 500            tabs.retain(|tab| !all_tabs[..initial_tabs_len].contains(tab));
 501            all_tabs.extend(tabs);
 502        }
 503
 504        controller.tab_groups.insert(0, all_tabs);
 505    }
 506
 507    /// Selects the next tab in the tab group in the trailing direction.
 508    pub fn select_next_tab(cx: &mut App, id: WindowId) {
 509        let mut controller = cx.global_mut::<SystemWindowTabController>();
 510        let Some(tabs) = controller.tabs(id) else {
 511            return;
 512        };
 513
 514        let current_index = tabs.iter().position(|tab| tab.id == id).unwrap();
 515        let next_index = (current_index + 1) % tabs.len();
 516
 517        let _ = &tabs[next_index].handle.update(cx, |_, window, _| {
 518            window.activate_window();
 519        });
 520    }
 521
 522    /// Selects the previous tab in the tab group in the leading direction.
 523    pub fn select_previous_tab(cx: &mut App, id: WindowId) {
 524        let mut controller = cx.global_mut::<SystemWindowTabController>();
 525        let Some(tabs) = controller.tabs(id) else {
 526            return;
 527        };
 528
 529        let current_index = tabs.iter().position(|tab| tab.id == id).unwrap();
 530        let previous_index = if current_index == 0 {
 531            tabs.len() - 1
 532        } else {
 533            current_index - 1
 534        };
 535
 536        let _ = &tabs[previous_index].handle.update(cx, |_, window, _| {
 537            window.activate_window();
 538        });
 539    }
 540}
 541
 542pub(crate) enum GpuiMode {
 543    #[cfg(any(test, feature = "test-support"))]
 544    Test {
 545        skip_drawing: bool,
 546    },
 547    Production,
 548}
 549
 550impl GpuiMode {
 551    #[cfg(any(test, feature = "test-support"))]
 552    pub fn test() -> Self {
 553        GpuiMode::Test {
 554            skip_drawing: false,
 555        }
 556    }
 557
 558    #[inline]
 559    pub(crate) fn skip_drawing(&self) -> bool {
 560        match self {
 561            #[cfg(any(test, feature = "test-support"))]
 562            GpuiMode::Test { skip_drawing } => *skip_drawing,
 563            GpuiMode::Production => false,
 564        }
 565    }
 566}
 567
 568/// Contains the state of the full application, and passed as a reference to a variety of callbacks.
 569/// Other [Context] derefs to this type.
 570/// You need a reference to an `App` to access the state of a [Entity].
 571pub struct App {
 572    pub(crate) this: Weak<AppCell>,
 573    pub(crate) platform: Rc<dyn Platform>,
 574    pub(crate) mode: GpuiMode,
 575    text_system: Arc<TextSystem>,
 576    flushing_effects: bool,
 577    pending_updates: usize,
 578    pub(crate) actions: Rc<ActionRegistry>,
 579    pub(crate) active_drag: Option<AnyDrag>,
 580    pub(crate) background_executor: BackgroundExecutor,
 581    pub(crate) foreground_executor: ForegroundExecutor,
 582    pub(crate) loading_assets: FxHashMap<(TypeId, u64), Box<dyn Any>>,
 583    asset_source: Arc<dyn AssetSource>,
 584    pub(crate) svg_renderer: SvgRenderer,
 585    http_client: Arc<dyn HttpClient>,
 586    pub(crate) globals_by_type: FxHashMap<TypeId, Box<dyn Any>>,
 587    pub(crate) entities: EntityMap,
 588    pub(crate) window_update_stack: Vec<WindowId>,
 589    pub(crate) new_entity_observers: SubscriberSet<TypeId, NewEntityListener>,
 590    pub(crate) windows: SlotMap<WindowId, Option<Box<Window>>>,
 591    pub(crate) window_handles: FxHashMap<WindowId, AnyWindowHandle>,
 592    pub(crate) focus_handles: Arc<FocusMap>,
 593    pub(crate) keymap: Rc<RefCell<Keymap>>,
 594    pub(crate) keyboard_layout: Box<dyn PlatformKeyboardLayout>,
 595    pub(crate) keyboard_mapper: Rc<dyn PlatformKeyboardMapper>,
 596    pub(crate) global_action_listeners:
 597        FxHashMap<TypeId, Vec<Rc<dyn Fn(&dyn Any, DispatchPhase, &mut Self)>>>,
 598    pending_effects: VecDeque<Effect>,
 599    pub(crate) pending_notifications: FxHashSet<EntityId>,
 600    pub(crate) pending_global_notifications: FxHashSet<TypeId>,
 601    pub(crate) observers: SubscriberSet<EntityId, Handler>,
 602    // TypeId is the type of the event that the listener callback expects
 603    pub(crate) event_listeners: SubscriberSet<EntityId, (TypeId, Listener)>,
 604    pub(crate) keystroke_observers: SubscriberSet<(), KeystrokeObserver>,
 605    pub(crate) keystroke_interceptors: SubscriberSet<(), KeystrokeObserver>,
 606    pub(crate) keyboard_layout_observers: SubscriberSet<(), Handler>,
 607    pub(crate) thermal_state_observers: SubscriberSet<(), Handler>,
 608    pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
 609    pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
 610    pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
 611    pub(crate) restart_observers: SubscriberSet<(), Handler>,
 612    pub(crate) restart_path: Option<PathBuf>,
 613    pub(crate) window_closed_observers: SubscriberSet<(), WindowClosedHandler>,
 614    pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
 615    pub(crate) propagate_event: bool,
 616    pub(crate) prompt_builder: Option<PromptBuilder>,
 617    pub(crate) window_invalidators_by_entity:
 618        FxHashMap<EntityId, FxHashMap<WindowId, WindowInvalidator>>,
 619    pub(crate) tracked_entities: FxHashMap<WindowId, FxHashSet<EntityId>>,
 620    #[cfg(any(feature = "inspector", debug_assertions))]
 621    pub(crate) inspector_renderer: Option<crate::InspectorRenderer>,
 622    #[cfg(any(feature = "inspector", debug_assertions))]
 623    pub(crate) inspector_element_registry: InspectorElementRegistry,
 624    #[cfg(any(test, feature = "test-support", debug_assertions))]
 625    pub(crate) name: Option<&'static str>,
 626    pub(crate) text_rendering_mode: Rc<Cell<TextRenderingMode>>,
 627    quit_mode: QuitMode,
 628    quitting: bool,
 629    /// Per-App element arena. This isolates element allocations between different
 630    /// App instances (important for tests where multiple Apps run concurrently).
 631    pub(crate) element_arena: RefCell<Arena>,
 632    /// Per-App event arena.
 633    pub(crate) event_arena: Arena,
 634}
 635
 636impl App {
 637    #[allow(clippy::new_ret_no_self)]
 638    pub(crate) fn new_app(
 639        platform: Rc<dyn Platform>,
 640        asset_source: Arc<dyn AssetSource>,
 641        http_client: Arc<dyn HttpClient>,
 642    ) -> Rc<AppCell> {
 643        let background_executor = platform.background_executor();
 644        let foreground_executor = platform.foreground_executor();
 645        assert!(
 646            background_executor.is_main_thread(),
 647            "must construct App on main thread"
 648        );
 649
 650        let text_system = Arc::new(TextSystem::new(platform.text_system()));
 651        let entities = EntityMap::new();
 652        let keyboard_layout = platform.keyboard_layout();
 653        let keyboard_mapper = platform.keyboard_mapper();
 654
 655        let app = Rc::new_cyclic(|this| AppCell {
 656            app: RefCell::new(App {
 657                this: this.clone(),
 658                platform: platform.clone(),
 659                text_system,
 660                text_rendering_mode: Rc::new(Cell::new(TextRenderingMode::default())),
 661                mode: GpuiMode::Production,
 662                actions: Rc::new(ActionRegistry::default()),
 663                flushing_effects: false,
 664                pending_updates: 0,
 665                active_drag: None,
 666                background_executor,
 667                foreground_executor,
 668                svg_renderer: SvgRenderer::new(asset_source.clone()),
 669                loading_assets: Default::default(),
 670                asset_source,
 671                http_client,
 672                globals_by_type: FxHashMap::default(),
 673                entities,
 674                new_entity_observers: SubscriberSet::new(),
 675                windows: SlotMap::with_key(),
 676                window_update_stack: Vec::new(),
 677                window_handles: FxHashMap::default(),
 678                focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
 679                keymap: Rc::new(RefCell::new(Keymap::default())),
 680                keyboard_layout,
 681                keyboard_mapper,
 682                global_action_listeners: FxHashMap::default(),
 683                pending_effects: VecDeque::new(),
 684                pending_notifications: FxHashSet::default(),
 685                pending_global_notifications: FxHashSet::default(),
 686                observers: SubscriberSet::new(),
 687                tracked_entities: FxHashMap::default(),
 688                window_invalidators_by_entity: FxHashMap::default(),
 689                event_listeners: SubscriberSet::new(),
 690                release_listeners: SubscriberSet::new(),
 691                keystroke_observers: SubscriberSet::new(),
 692                keystroke_interceptors: SubscriberSet::new(),
 693                keyboard_layout_observers: SubscriberSet::new(),
 694                thermal_state_observers: SubscriberSet::new(),
 695                global_observers: SubscriberSet::new(),
 696                quit_observers: SubscriberSet::new(),
 697                restart_observers: SubscriberSet::new(),
 698                restart_path: None,
 699                window_closed_observers: SubscriberSet::new(),
 700                layout_id_buffer: Default::default(),
 701                propagate_event: true,
 702                prompt_builder: Some(PromptBuilder::Default),
 703                #[cfg(any(feature = "inspector", debug_assertions))]
 704                inspector_renderer: None,
 705                #[cfg(any(feature = "inspector", debug_assertions))]
 706                inspector_element_registry: InspectorElementRegistry::default(),
 707                quit_mode: QuitMode::default(),
 708                quitting: false,
 709
 710                #[cfg(any(test, feature = "test-support", debug_assertions))]
 711                name: None,
 712                element_arena: RefCell::new(Arena::new(1024 * 1024)),
 713                event_arena: Arena::new(1024 * 1024),
 714            }),
 715        });
 716
 717        init_app_menus(platform.as_ref(), &app.borrow());
 718        SystemWindowTabController::init(&mut app.borrow_mut());
 719
 720        platform.on_keyboard_layout_change(Box::new({
 721            let app = Rc::downgrade(&app);
 722            move || {
 723                if let Some(app) = app.upgrade() {
 724                    let cx = &mut app.borrow_mut();
 725                    cx.keyboard_layout = cx.platform.keyboard_layout();
 726                    cx.keyboard_mapper = cx.platform.keyboard_mapper();
 727                    cx.keyboard_layout_observers
 728                        .clone()
 729                        .retain(&(), move |callback| (callback)(cx));
 730                }
 731            }
 732        }));
 733
 734        platform.on_thermal_state_change(Box::new({
 735            let app = Rc::downgrade(&app);
 736            move || {
 737                if let Some(app) = app.upgrade() {
 738                    let cx = &mut app.borrow_mut();
 739                    cx.thermal_state_observers
 740                        .clone()
 741                        .retain(&(), move |callback| (callback)(cx));
 742                }
 743            }
 744        }));
 745
 746        platform.on_quit(Box::new({
 747            let cx = app.clone();
 748            move || {
 749                cx.borrow_mut().shutdown();
 750            }
 751        }));
 752
 753        app
 754    }
 755
 756    #[doc(hidden)]
 757    pub fn ref_counts_drop_handle(&self) -> impl Sized + use<> {
 758        self.entities.ref_counts_drop_handle()
 759    }
 760
 761    /// Captures a snapshot of all entities that currently have alive handles.
 762    ///
 763    /// The returned [`LeakDetectorSnapshot`] can later be passed to
 764    /// [`assert_no_new_leaks`](Self::assert_no_new_leaks) to verify that no
 765    /// entities created after the snapshot are still alive.
 766    #[cfg(any(test, feature = "leak-detection"))]
 767    pub fn leak_detector_snapshot(&self) -> LeakDetectorSnapshot {
 768        self.entities.leak_detector_snapshot()
 769    }
 770
 771    /// Asserts that no entities created after `snapshot` still have alive handles.
 772    ///
 773    /// Entities that were already tracked at the time of the snapshot are ignored,
 774    /// even if they still have handles. Only *new* entities (those whose
 775    /// `EntityId` was not present in the snapshot) are considered leaks.
 776    ///
 777    /// # Panics
 778    ///
 779    /// Panics if any new entity handles exist. The panic message lists every
 780    /// leaked entity with its type name, and includes allocation-site backtraces
 781    /// when `LEAK_BACKTRACE` is set.
 782    #[cfg(any(test, feature = "leak-detection"))]
 783    pub fn assert_no_new_leaks(&self, snapshot: &LeakDetectorSnapshot) {
 784        self.entities.assert_no_new_leaks(snapshot)
 785    }
 786
 787    /// Quit the application gracefully. Handlers registered with [`Context::on_app_quit`]
 788    /// will be given 100ms to complete before exiting.
 789    pub fn shutdown(&mut self) {
 790        let mut futures = Vec::new();
 791
 792        for observer in self.quit_observers.remove(&()) {
 793            futures.push(observer(self));
 794        }
 795
 796        self.windows.clear();
 797        self.window_handles.clear();
 798        self.flush_effects();
 799        self.quitting = true;
 800
 801        let futures = futures::future::join_all(futures);
 802        if self
 803            .foreground_executor
 804            .block_with_timeout(SHUTDOWN_TIMEOUT, futures)
 805            .is_err()
 806        {
 807            log::error!("timed out waiting on app_will_quit");
 808        }
 809
 810        self.quitting = false;
 811    }
 812
 813    /// Get the id of the current keyboard layout
 814    pub fn keyboard_layout(&self) -> &dyn PlatformKeyboardLayout {
 815        self.keyboard_layout.as_ref()
 816    }
 817
 818    /// Get the current keyboard mapper.
 819    pub fn keyboard_mapper(&self) -> &Rc<dyn PlatformKeyboardMapper> {
 820        &self.keyboard_mapper
 821    }
 822
 823    /// Invokes a handler when the current keyboard layout changes
 824    pub fn on_keyboard_layout_change<F>(&self, mut callback: F) -> Subscription
 825    where
 826        F: 'static + FnMut(&mut App),
 827    {
 828        let (subscription, activate) = self.keyboard_layout_observers.insert(
 829            (),
 830            Box::new(move |cx| {
 831                callback(cx);
 832                true
 833            }),
 834        );
 835        activate();
 836        subscription
 837    }
 838
 839    /// Gracefully quit the application via the platform's standard routine.
 840    pub fn quit(&self) {
 841        self.platform.quit();
 842    }
 843
 844    /// Schedules all windows in the application to be redrawn. This can be called
 845    /// multiple times in an update cycle and still result in a single redraw.
 846    pub fn refresh_windows(&mut self) {
 847        self.pending_effects.push_back(Effect::RefreshWindows);
 848    }
 849
 850    pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
 851        self.start_update();
 852        let result = update(self);
 853        self.finish_update();
 854        result
 855    }
 856
 857    pub(crate) fn start_update(&mut self) {
 858        self.pending_updates += 1;
 859    }
 860
 861    pub(crate) fn finish_update(&mut self) {
 862        if !self.flushing_effects && self.pending_updates == 1 {
 863            self.flushing_effects = true;
 864            self.flush_effects();
 865            self.flushing_effects = false;
 866        }
 867        self.pending_updates -= 1;
 868    }
 869
 870    /// Arrange a callback to be invoked when the given entity calls `notify` on its respective context.
 871    pub fn observe<W>(
 872        &mut self,
 873        entity: &Entity<W>,
 874        mut on_notify: impl FnMut(Entity<W>, &mut App) + 'static,
 875    ) -> Subscription
 876    where
 877        W: 'static,
 878    {
 879        self.observe_internal(entity, move |e, cx| {
 880            on_notify(e, cx);
 881            true
 882        })
 883    }
 884
 885    pub(crate) fn detect_accessed_entities<R>(
 886        &mut self,
 887        callback: impl FnOnce(&mut App) -> R,
 888    ) -> (R, FxHashSet<EntityId>) {
 889        let accessed_entities_start = self.entities.accessed_entities.get_mut().clone();
 890        let result = callback(self);
 891        let entities_accessed_in_callback = self
 892            .entities
 893            .accessed_entities
 894            .get_mut()
 895            .difference(&accessed_entities_start)
 896            .copied()
 897            .collect::<FxHashSet<EntityId>>();
 898        (result, entities_accessed_in_callback)
 899    }
 900
 901    pub(crate) fn record_entities_accessed(
 902        &mut self,
 903        window_handle: AnyWindowHandle,
 904        invalidator: WindowInvalidator,
 905        entities: &FxHashSet<EntityId>,
 906    ) {
 907        let mut tracked_entities =
 908            std::mem::take(self.tracked_entities.entry(window_handle.id).or_default());
 909        for entity in tracked_entities.iter() {
 910            self.window_invalidators_by_entity
 911                .entry(*entity)
 912                .and_modify(|windows| {
 913                    windows.remove(&window_handle.id);
 914                });
 915        }
 916        for entity in entities.iter() {
 917            self.window_invalidators_by_entity
 918                .entry(*entity)
 919                .or_default()
 920                .insert(window_handle.id, invalidator.clone());
 921        }
 922        tracked_entities.clear();
 923        tracked_entities.extend(entities.iter().copied());
 924        self.tracked_entities
 925            .insert(window_handle.id, tracked_entities);
 926    }
 927
 928    pub(crate) fn new_observer(&mut self, key: EntityId, value: Handler) -> Subscription {
 929        let (subscription, activate) = self.observers.insert(key, value);
 930        self.defer(move |_| activate());
 931        subscription
 932    }
 933
 934    pub(crate) fn observe_internal<W>(
 935        &mut self,
 936        entity: &Entity<W>,
 937        mut on_notify: impl FnMut(Entity<W>, &mut App) -> bool + 'static,
 938    ) -> Subscription
 939    where
 940        W: 'static,
 941    {
 942        let entity_id = entity.entity_id();
 943        let handle = entity.downgrade();
 944        self.new_observer(
 945            entity_id,
 946            Box::new(move |cx| {
 947                if let Some(entity) = handle.upgrade() {
 948                    on_notify(entity, cx)
 949                } else {
 950                    false
 951                }
 952            }),
 953        )
 954    }
 955
 956    /// Arrange for the given callback to be invoked whenever the given entity emits an event of a given type.
 957    /// The callback is provided a handle to the emitting entity and a reference to the emitted event.
 958    pub fn subscribe<T, Event>(
 959        &mut self,
 960        entity: &Entity<T>,
 961        mut on_event: impl FnMut(Entity<T>, &Event, &mut App) + 'static,
 962    ) -> Subscription
 963    where
 964        T: 'static + EventEmitter<Event>,
 965        Event: 'static,
 966    {
 967        self.subscribe_internal(entity, move |entity, event, cx| {
 968            on_event(entity, event, cx);
 969            true
 970        })
 971    }
 972
 973    pub(crate) fn new_subscription(
 974        &mut self,
 975        key: EntityId,
 976        value: (TypeId, Listener),
 977    ) -> Subscription {
 978        let (subscription, activate) = self.event_listeners.insert(key, value);
 979        self.defer(move |_| activate());
 980        subscription
 981    }
 982    pub(crate) fn subscribe_internal<T, Evt>(
 983        &mut self,
 984        entity: &Entity<T>,
 985        mut on_event: impl FnMut(Entity<T>, &Evt, &mut App) -> bool + 'static,
 986    ) -> Subscription
 987    where
 988        T: 'static + EventEmitter<Evt>,
 989        Evt: 'static,
 990    {
 991        let entity_id = entity.entity_id();
 992        let handle = entity.downgrade();
 993        self.new_subscription(
 994            entity_id,
 995            (
 996                TypeId::of::<Evt>(),
 997                Box::new(move |event, cx| {
 998                    let event: &Evt = event.downcast_ref().expect("invalid event type");
 999                    if let Some(entity) = handle.upgrade() {
1000                        on_event(entity, event, cx)
1001                    } else {
1002                        false
1003                    }
1004                }),
1005            ),
1006        )
1007    }
1008
1009    /// Returns handles to all open windows in the application.
1010    /// Each handle could be downcast to a handle typed for the root view of that window.
1011    /// To find all windows of a given type, you could filter on
1012    pub fn windows(&self) -> Vec<AnyWindowHandle> {
1013        self.windows
1014            .keys()
1015            .flat_map(|window_id| self.window_handles.get(&window_id).copied())
1016            .collect()
1017    }
1018
1019    /// Returns the window handles ordered by their appearance on screen, front to back.
1020    ///
1021    /// The first window in the returned list is the active/topmost window of the application.
1022    ///
1023    /// This method returns None if the platform doesn't implement the method yet.
1024    pub fn window_stack(&self) -> Option<Vec<AnyWindowHandle>> {
1025        self.platform.window_stack()
1026    }
1027
1028    /// Returns a handle to the window that is currently focused at the platform level, if one exists.
1029    pub fn active_window(&self) -> Option<AnyWindowHandle> {
1030        self.platform.active_window()
1031    }
1032
1033    /// Opens a new window with the given option and the root view returned by the given function.
1034    /// The function is invoked with a `Window`, which can be used to interact with window-specific
1035    /// functionality.
1036    pub fn open_window<V: 'static + Render>(
1037        &mut self,
1038        options: crate::WindowOptions,
1039        build_root_view: impl FnOnce(&mut Window, &mut App) -> Entity<V>,
1040    ) -> anyhow::Result<WindowHandle<V>> {
1041        self.update(|cx| {
1042            let id = cx.windows.insert(None);
1043            let handle = WindowHandle::new(id);
1044            match Window::new(handle.into(), options, cx) {
1045                Ok(mut window) => {
1046                    cx.window_update_stack.push(id);
1047                    let root_view = build_root_view(&mut window, cx);
1048                    cx.window_update_stack.pop();
1049                    window.root.replace(root_view.into());
1050                    window.defer(cx, |window: &mut Window, cx| window.appearance_changed(cx));
1051
1052                    // allow a window to draw at least once before returning
1053                    // this didn't cause any issues on non windows platforms as it seems we always won the race to on_request_frame
1054                    // on windows we quite frequently lose the race and return a window that has never rendered, which leads to a crash
1055                    // where DispatchTree::root_node_id asserts on empty nodes
1056                    let clear = window.draw(cx);
1057                    clear.clear();
1058
1059                    cx.window_handles.insert(id, window.handle);
1060                    cx.windows.get_mut(id).unwrap().replace(Box::new(window));
1061                    Ok(handle)
1062                }
1063                Err(e) => {
1064                    cx.windows.remove(id);
1065                    Err(e)
1066                }
1067            }
1068        })
1069    }
1070
1071    /// Instructs the platform to activate the application by bringing it to the foreground.
1072    pub fn activate(&self, ignoring_other_apps: bool) {
1073        self.platform.activate(ignoring_other_apps);
1074    }
1075
1076    /// Hide the application at the platform level.
1077    pub fn hide(&self) {
1078        self.platform.hide();
1079    }
1080
1081    /// Hide other applications at the platform level.
1082    pub fn hide_other_apps(&self) {
1083        self.platform.hide_other_apps();
1084    }
1085
1086    /// Unhide other applications at the platform level.
1087    pub fn unhide_other_apps(&self) {
1088        self.platform.unhide_other_apps();
1089    }
1090
1091    /// Returns the list of currently active displays.
1092    pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
1093        self.platform.displays()
1094    }
1095
1096    /// Returns the primary display that will be used for new windows.
1097    pub fn primary_display(&self) -> Option<Rc<dyn PlatformDisplay>> {
1098        self.platform.primary_display()
1099    }
1100
1101    /// Returns whether `screen_capture_sources` may work.
1102    pub fn is_screen_capture_supported(&self) -> bool {
1103        self.platform.is_screen_capture_supported()
1104    }
1105
1106    /// Returns a list of available screen capture sources.
1107    pub fn screen_capture_sources(
1108        &self,
1109    ) -> oneshot::Receiver<Result<Vec<Rc<dyn ScreenCaptureSource>>>> {
1110        self.platform.screen_capture_sources()
1111    }
1112
1113    /// Returns the display with the given ID, if one exists.
1114    pub fn find_display(&self, id: DisplayId) -> Option<Rc<dyn PlatformDisplay>> {
1115        self.displays()
1116            .iter()
1117            .find(|display| display.id() == id)
1118            .cloned()
1119    }
1120
1121    /// Returns the current thermal state of the system.
1122    pub fn thermal_state(&self) -> ThermalState {
1123        self.platform.thermal_state()
1124    }
1125
1126    /// Invokes a handler when the thermal state changes
1127    pub fn on_thermal_state_change<F>(&self, mut callback: F) -> Subscription
1128    where
1129        F: 'static + FnMut(&mut App),
1130    {
1131        let (subscription, activate) = self.thermal_state_observers.insert(
1132            (),
1133            Box::new(move |cx| {
1134                callback(cx);
1135                true
1136            }),
1137        );
1138        activate();
1139        subscription
1140    }
1141
1142    /// Returns the appearance of the application's windows.
1143    pub fn window_appearance(&self) -> WindowAppearance {
1144        self.platform.window_appearance()
1145    }
1146
1147    /// Reads data from the platform clipboard.
1148    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
1149        self.platform.read_from_clipboard()
1150    }
1151
1152    /// Sets the text rendering mode for the application.
1153    pub fn set_text_rendering_mode(&mut self, mode: TextRenderingMode) {
1154        self.text_rendering_mode.set(mode);
1155    }
1156
1157    /// Returns the current text rendering mode for the application.
1158    pub fn text_rendering_mode(&self) -> TextRenderingMode {
1159        self.text_rendering_mode.get()
1160    }
1161
1162    /// Writes data to the platform clipboard.
1163    pub fn write_to_clipboard(&self, item: ClipboardItem) {
1164        self.platform.write_to_clipboard(item)
1165    }
1166
1167    /// Reads data from the primary selection buffer.
1168    /// Only available on Linux.
1169    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
1170    pub fn read_from_primary(&self) -> Option<ClipboardItem> {
1171        self.platform.read_from_primary()
1172    }
1173
1174    /// Writes data to the primary selection buffer.
1175    /// Only available on Linux.
1176    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
1177    pub fn write_to_primary(&self, item: ClipboardItem) {
1178        self.platform.write_to_primary(item)
1179    }
1180
1181    /// Reads data from macOS's "Find" pasteboard.
1182    ///
1183    /// Used to share the current search string between apps.
1184    ///
1185    /// https://developer.apple.com/documentation/appkit/nspasteboard/name-swift.struct/find
1186    #[cfg(target_os = "macos")]
1187    pub fn read_from_find_pasteboard(&self) -> Option<ClipboardItem> {
1188        self.platform.read_from_find_pasteboard()
1189    }
1190
1191    /// Writes data to macOS's "Find" pasteboard.
1192    ///
1193    /// Used to share the current search string between apps.
1194    ///
1195    /// https://developer.apple.com/documentation/appkit/nspasteboard/name-swift.struct/find
1196    #[cfg(target_os = "macos")]
1197    pub fn write_to_find_pasteboard(&self, item: ClipboardItem) {
1198        self.platform.write_to_find_pasteboard(item)
1199    }
1200
1201    /// Writes credentials to the platform keychain.
1202    pub fn write_credentials(
1203        &self,
1204        url: &str,
1205        username: &str,
1206        password: &[u8],
1207    ) -> Task<Result<()>> {
1208        self.platform.write_credentials(url, username, password)
1209    }
1210
1211    /// Reads credentials from the platform keychain.
1212    pub fn read_credentials(&self, url: &str) -> Task<Result<Option<(String, Vec<u8>)>>> {
1213        self.platform.read_credentials(url)
1214    }
1215
1216    /// Deletes credentials from the platform keychain.
1217    pub fn delete_credentials(&self, url: &str) -> Task<Result<()>> {
1218        self.platform.delete_credentials(url)
1219    }
1220
1221    /// Directs the platform's default browser to open the given URL.
1222    pub fn open_url(&self, url: &str) {
1223        self.platform.open_url(url);
1224    }
1225
1226    /// Registers the given URL scheme (e.g. `zed` for `zed://` urls) to be
1227    /// opened by the current app.
1228    ///
1229    /// On some platforms (e.g. macOS) you may be able to register URL schemes
1230    /// as part of app distribution, but this method exists to let you register
1231    /// schemes at runtime.
1232    pub fn register_url_scheme(&self, scheme: &str) -> Task<Result<()>> {
1233        self.platform.register_url_scheme(scheme)
1234    }
1235
1236    /// Returns the full pathname of the current app bundle.
1237    ///
1238    /// Returns an error if the app is not being run from a bundle.
1239    pub fn app_path(&self) -> Result<PathBuf> {
1240        self.platform.app_path()
1241    }
1242
1243    /// On Linux, returns the name of the compositor in use.
1244    ///
1245    /// Returns an empty string on other platforms.
1246    pub fn compositor_name(&self) -> &'static str {
1247        self.platform.compositor_name()
1248    }
1249
1250    /// Returns the file URL of the executable with the specified name in the application bundle
1251    pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
1252        self.platform.path_for_auxiliary_executable(name)
1253    }
1254
1255    /// Displays a platform modal for selecting paths.
1256    ///
1257    /// When one or more paths are selected, they'll be relayed asynchronously via the returned oneshot channel.
1258    /// If cancelled, a `None` will be relayed instead.
1259    /// May return an error on Linux if the file picker couldn't be opened.
1260    pub fn prompt_for_paths(
1261        &self,
1262        options: PathPromptOptions,
1263    ) -> oneshot::Receiver<Result<Option<Vec<PathBuf>>>> {
1264        self.platform.prompt_for_paths(options)
1265    }
1266
1267    /// Displays a platform modal for selecting a new path where a file can be saved.
1268    ///
1269    /// The provided directory will be used to set the initial location.
1270    /// When a path is selected, it is relayed asynchronously via the returned oneshot channel.
1271    /// If cancelled, a `None` will be relayed instead.
1272    /// May return an error on Linux if the file picker couldn't be opened.
1273    pub fn prompt_for_new_path(
1274        &self,
1275        directory: &Path,
1276        suggested_name: Option<&str>,
1277    ) -> oneshot::Receiver<Result<Option<PathBuf>>> {
1278        self.platform.prompt_for_new_path(directory, suggested_name)
1279    }
1280
1281    /// Reveals the specified path at the platform level, such as in Finder on macOS.
1282    pub fn reveal_path(&self, path: &Path) {
1283        self.platform.reveal_path(path)
1284    }
1285
1286    /// Opens the specified path with the system's default application.
1287    pub fn open_with_system(&self, path: &Path) {
1288        self.platform.open_with_system(path)
1289    }
1290
1291    /// Returns whether the user has configured scrollbars to auto-hide at the platform level.
1292    pub fn should_auto_hide_scrollbars(&self) -> bool {
1293        self.platform.should_auto_hide_scrollbars()
1294    }
1295
1296    /// Restarts the application.
1297    pub fn restart(&mut self) {
1298        self.restart_observers
1299            .clone()
1300            .retain(&(), |observer| observer(self));
1301        self.platform.restart(self.restart_path.take())
1302    }
1303
1304    /// Sets the path to use when restarting the application.
1305    pub fn set_restart_path(&mut self, path: PathBuf) {
1306        self.restart_path = Some(path);
1307    }
1308
1309    /// Returns the HTTP client for the application.
1310    pub fn http_client(&self) -> Arc<dyn HttpClient> {
1311        self.http_client.clone()
1312    }
1313
1314    /// Sets the HTTP client for the application.
1315    pub fn set_http_client(&mut self, new_client: Arc<dyn HttpClient>) {
1316        self.http_client = new_client;
1317    }
1318
1319    /// Configures when the application should automatically quit.
1320    /// By default, [`QuitMode::Default`] is used.
1321    pub fn set_quit_mode(&mut self, mode: QuitMode) {
1322        self.quit_mode = mode;
1323    }
1324
1325    /// Returns the SVG renderer used by the application.
1326    pub fn svg_renderer(&self) -> SvgRenderer {
1327        self.svg_renderer.clone()
1328    }
1329
1330    pub(crate) fn push_effect(&mut self, effect: Effect) {
1331        match &effect {
1332            Effect::Notify { emitter } => {
1333                if !self.pending_notifications.insert(*emitter) {
1334                    return;
1335                }
1336            }
1337            Effect::NotifyGlobalObservers { global_type } => {
1338                if !self.pending_global_notifications.insert(*global_type) {
1339                    return;
1340                }
1341            }
1342            _ => {}
1343        };
1344
1345        self.pending_effects.push_back(effect);
1346    }
1347
1348    /// Called at the end of [`App::update`] to complete any side effects
1349    /// such as notifying observers, emitting events, etc. Effects can themselves
1350    /// cause effects, so we continue looping until all effects are processed.
1351    fn flush_effects(&mut self) {
1352        loop {
1353            self.release_dropped_entities();
1354            self.release_dropped_focus_handles();
1355            if let Some(effect) = self.pending_effects.pop_front() {
1356                match effect {
1357                    Effect::Notify { emitter } => {
1358                        self.apply_notify_effect(emitter);
1359                    }
1360
1361                    Effect::Emit {
1362                        emitter,
1363                        event_type,
1364                        event,
1365                    } => self.apply_emit_effect(emitter, event_type, &*event),
1366
1367                    Effect::RefreshWindows => {
1368                        self.apply_refresh_effect();
1369                    }
1370
1371                    Effect::NotifyGlobalObservers { global_type } => {
1372                        self.apply_notify_global_observers_effect(global_type);
1373                    }
1374
1375                    Effect::Defer { callback } => {
1376                        self.apply_defer_effect(callback);
1377                    }
1378                    Effect::EntityCreated {
1379                        entity,
1380                        tid,
1381                        window,
1382                    } => {
1383                        self.apply_entity_created_effect(entity, tid, window);
1384                    }
1385                }
1386            } else {
1387                #[cfg(any(test, feature = "test-support"))]
1388                for window in self
1389                    .windows
1390                    .values()
1391                    .filter_map(|window| {
1392                        let window = window.as_deref()?;
1393                        window.invalidator.is_dirty().then_some(window.handle)
1394                    })
1395                    .collect::<Vec<_>>()
1396                {
1397                    self.update_window(window, |_, window, cx| window.draw(cx).clear())
1398                        .unwrap();
1399                }
1400
1401                if self.pending_effects.is_empty() {
1402                    self.event_arena.clear();
1403                    break;
1404                }
1405            }
1406        }
1407    }
1408
1409    /// Repeatedly called during `flush_effects` to release any entities whose
1410    /// reference count has become zero. We invoke any release observers before dropping
1411    /// each entity.
1412    fn release_dropped_entities(&mut self) {
1413        loop {
1414            let dropped = self.entities.take_dropped();
1415            if dropped.is_empty() {
1416                break;
1417            }
1418
1419            for (entity_id, mut entity) in dropped {
1420                self.observers.remove(&entity_id);
1421                self.event_listeners.remove(&entity_id);
1422                for release_callback in self.release_listeners.remove(&entity_id) {
1423                    release_callback(entity.as_mut(), self);
1424                }
1425            }
1426        }
1427    }
1428
1429    /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
1430    fn release_dropped_focus_handles(&mut self) {
1431        self.focus_handles
1432            .clone()
1433            .write()
1434            .retain(|handle_id, focus| {
1435                if focus.ref_count.load(SeqCst) == 0 {
1436                    for window_handle in self.windows() {
1437                        window_handle
1438                            .update(self, |_, window, _| {
1439                                if window.focus == Some(handle_id) {
1440                                    window.blur();
1441                                }
1442                            })
1443                            .unwrap();
1444                    }
1445                    false
1446                } else {
1447                    true
1448                }
1449            });
1450    }
1451
1452    fn apply_notify_effect(&mut self, emitter: EntityId) {
1453        self.pending_notifications.remove(&emitter);
1454
1455        self.observers
1456            .clone()
1457            .retain(&emitter, |handler| handler(self));
1458    }
1459
1460    fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: &dyn Any) {
1461        self.event_listeners
1462            .clone()
1463            .retain(&emitter, |(stored_type, handler)| {
1464                if *stored_type == event_type {
1465                    handler(event, self)
1466                } else {
1467                    true
1468                }
1469            });
1470    }
1471
1472    fn apply_refresh_effect(&mut self) {
1473        for window in self.windows.values_mut() {
1474            if let Some(window) = window.as_deref_mut() {
1475                window.refreshing = true;
1476                window.invalidator.set_dirty(true);
1477            }
1478        }
1479    }
1480
1481    fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
1482        self.pending_global_notifications.remove(&type_id);
1483        self.global_observers
1484            .clone()
1485            .retain(&type_id, |observer| observer(self));
1486    }
1487
1488    fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
1489        callback(self);
1490    }
1491
1492    fn apply_entity_created_effect(
1493        &mut self,
1494        entity: AnyEntity,
1495        tid: TypeId,
1496        window: Option<WindowId>,
1497    ) {
1498        self.new_entity_observers.clone().retain(&tid, |observer| {
1499            if let Some(id) = window {
1500                self.update_window_id(id, {
1501                    let entity = entity.clone();
1502                    |_, window, cx| (observer)(entity, &mut Some(window), cx)
1503                })
1504                .expect("All windows should be off the stack when flushing effects");
1505            } else {
1506                (observer)(entity.clone(), &mut None, self)
1507            }
1508            true
1509        });
1510    }
1511
1512    fn update_window_id<T, F>(&mut self, id: WindowId, update: F) -> Result<T>
1513    where
1514        F: FnOnce(AnyView, &mut Window, &mut App) -> T,
1515    {
1516        self.update(|cx| {
1517            let mut window = cx.windows.get_mut(id)?.take()?;
1518
1519            let root_view = window.root.clone().unwrap();
1520
1521            cx.window_update_stack.push(window.handle.id);
1522            let result = update(root_view, &mut window, cx);
1523            fn trail(id: WindowId, window: Box<Window>, cx: &mut App) -> Option<()> {
1524                cx.window_update_stack.pop();
1525
1526                if window.removed {
1527                    cx.window_handles.remove(&id);
1528                    cx.windows.remove(id);
1529
1530                    cx.window_closed_observers.clone().retain(&(), |callback| {
1531                        callback(cx);
1532                        true
1533                    });
1534
1535                    let quit_on_empty = match cx.quit_mode {
1536                        QuitMode::Explicit => false,
1537                        QuitMode::LastWindowClosed => true,
1538                        QuitMode::Default => cfg!(not(target_os = "macos")),
1539                    };
1540
1541                    if quit_on_empty && cx.windows.is_empty() {
1542                        cx.quit();
1543                    }
1544                } else {
1545                    cx.windows.get_mut(id)?.replace(window);
1546                }
1547                Some(())
1548            }
1549            trail(id, window, cx)?;
1550
1551            Some(result)
1552        })
1553        .context("window not found")
1554    }
1555
1556    /// Creates an `AsyncApp`, which can be cloned and has a static lifetime
1557    /// so it can be held across `await` points.
1558    pub fn to_async(&self) -> AsyncApp {
1559        AsyncApp {
1560            app: self.this.clone(),
1561            background_executor: self.background_executor.clone(),
1562            foreground_executor: self.foreground_executor.clone(),
1563        }
1564    }
1565
1566    /// Obtains a reference to the executor, which can be used to spawn futures.
1567    pub fn background_executor(&self) -> &BackgroundExecutor {
1568        &self.background_executor
1569    }
1570
1571    /// Obtains a reference to the executor, which can be used to spawn futures.
1572    pub fn foreground_executor(&self) -> &ForegroundExecutor {
1573        if self.quitting {
1574            panic!("Can't spawn on main thread after on_app_quit")
1575        };
1576        &self.foreground_executor
1577    }
1578
1579    /// Spawns the future returned by the given function on the main thread. The closure will be invoked
1580    /// with [AsyncApp], which allows the application state to be accessed across await points.
1581    #[track_caller]
1582    pub fn spawn<AsyncFn, R>(&self, f: AsyncFn) -> Task<R>
1583    where
1584        AsyncFn: AsyncFnOnce(&mut AsyncApp) -> R + 'static,
1585        R: 'static,
1586    {
1587        if self.quitting {
1588            debug_panic!("Can't spawn on main thread after on_app_quit")
1589        };
1590
1591        let mut cx = self.to_async();
1592
1593        self.foreground_executor
1594            .spawn(async move { f(&mut cx).await }.boxed_local())
1595    }
1596
1597    /// Spawns the future returned by the given function on the main thread with
1598    /// the given priority. The closure will be invoked with [AsyncApp], which
1599    /// allows the application state to be accessed across await points.
1600    pub fn spawn_with_priority<AsyncFn, R>(&self, priority: Priority, f: AsyncFn) -> Task<R>
1601    where
1602        AsyncFn: AsyncFnOnce(&mut AsyncApp) -> R + 'static,
1603        R: 'static,
1604    {
1605        if self.quitting {
1606            debug_panic!("Can't spawn on main thread after on_app_quit")
1607        };
1608
1609        let mut cx = self.to_async();
1610
1611        self.foreground_executor
1612            .spawn_with_priority(priority, async move { f(&mut cx).await }.boxed_local())
1613    }
1614
1615    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1616    /// that are currently on the stack to be returned to the app.
1617    pub fn defer(&mut self, f: impl FnOnce(&mut App) + 'static) {
1618        self.push_effect(Effect::Defer {
1619            callback: Box::new(f),
1620        });
1621    }
1622
1623    /// Accessor for the application's asset source, which is provided when constructing the `App`.
1624    pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
1625        &self.asset_source
1626    }
1627
1628    /// Accessor for the text system.
1629    pub fn text_system(&self) -> &Arc<TextSystem> {
1630        &self.text_system
1631    }
1632
1633    /// Check whether a global of the given type has been assigned.
1634    pub fn has_global<G: Global>(&self) -> bool {
1635        self.globals_by_type.contains_key(&TypeId::of::<G>())
1636    }
1637
1638    /// Access the global of the given type. Panics if a global for that type has not been assigned.
1639    #[track_caller]
1640    pub fn global<G: Global>(&self) -> &G {
1641        self.globals_by_type
1642            .get(&TypeId::of::<G>())
1643            .map(|any_state| any_state.downcast_ref::<G>().unwrap())
1644            .with_context(|| format!("no state of type {} exists", type_name::<G>()))
1645            .unwrap()
1646    }
1647
1648    /// Access the global of the given type if a value has been assigned.
1649    pub fn try_global<G: Global>(&self) -> Option<&G> {
1650        self.globals_by_type
1651            .get(&TypeId::of::<G>())
1652            .map(|any_state| any_state.downcast_ref::<G>().unwrap())
1653    }
1654
1655    /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
1656    #[track_caller]
1657    pub fn global_mut<G: Global>(&mut self) -> &mut G {
1658        let global_type = TypeId::of::<G>();
1659        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1660        self.globals_by_type
1661            .get_mut(&global_type)
1662            .and_then(|any_state| any_state.downcast_mut::<G>())
1663            .with_context(|| format!("no state of type {} exists", type_name::<G>()))
1664            .unwrap()
1665    }
1666
1667    /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
1668    /// yet been assigned.
1669    pub fn default_global<G: Global + Default>(&mut self) -> &mut G {
1670        let global_type = TypeId::of::<G>();
1671        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1672        self.globals_by_type
1673            .entry(global_type)
1674            .or_insert_with(|| Box::<G>::default())
1675            .downcast_mut::<G>()
1676            .unwrap()
1677    }
1678
1679    /// Sets the value of the global of the given type.
1680    pub fn set_global<G: Global>(&mut self, global: G) {
1681        let global_type = TypeId::of::<G>();
1682        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1683        self.globals_by_type.insert(global_type, Box::new(global));
1684    }
1685
1686    /// Clear all stored globals. Does not notify global observers.
1687    #[cfg(any(test, feature = "test-support"))]
1688    pub fn clear_globals(&mut self) {
1689        self.globals_by_type.drain();
1690    }
1691
1692    /// Remove the global of the given type from the app context. Does not notify global observers.
1693    pub fn remove_global<G: Global>(&mut self) -> G {
1694        let global_type = TypeId::of::<G>();
1695        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1696        *self
1697            .globals_by_type
1698            .remove(&global_type)
1699            .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
1700            .downcast()
1701            .unwrap()
1702    }
1703
1704    /// Register a callback to be invoked when a global of the given type is updated.
1705    pub fn observe_global<G: Global>(
1706        &mut self,
1707        mut f: impl FnMut(&mut Self) + 'static,
1708    ) -> Subscription {
1709        let (subscription, activate) = self.global_observers.insert(
1710            TypeId::of::<G>(),
1711            Box::new(move |cx| {
1712                f(cx);
1713                true
1714            }),
1715        );
1716        self.defer(move |_| activate());
1717        subscription
1718    }
1719
1720    /// Move the global of the given type to the stack.
1721    #[track_caller]
1722    pub(crate) fn lease_global<G: Global>(&mut self) -> GlobalLease<G> {
1723        GlobalLease::new(
1724            self.globals_by_type
1725                .remove(&TypeId::of::<G>())
1726                .with_context(|| format!("no global registered of type {}", type_name::<G>()))
1727                .unwrap(),
1728        )
1729    }
1730
1731    /// Restore the global of the given type after it is moved to the stack.
1732    pub(crate) fn end_global_lease<G: Global>(&mut self, lease: GlobalLease<G>) {
1733        let global_type = TypeId::of::<G>();
1734
1735        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1736        self.globals_by_type.insert(global_type, lease.global);
1737    }
1738
1739    pub(crate) fn new_entity_observer(
1740        &self,
1741        key: TypeId,
1742        value: NewEntityListener,
1743    ) -> Subscription {
1744        let (subscription, activate) = self.new_entity_observers.insert(key, value);
1745        activate();
1746        subscription
1747    }
1748
1749    /// Arrange for the given function to be invoked whenever a view of the specified type is created.
1750    /// The function will be passed a mutable reference to the view along with an appropriate context.
1751    pub fn observe_new<T: 'static>(
1752        &self,
1753        on_new: impl 'static + Fn(&mut T, Option<&mut Window>, &mut Context<T>),
1754    ) -> Subscription {
1755        self.new_entity_observer(
1756            TypeId::of::<T>(),
1757            Box::new(
1758                move |any_entity: AnyEntity, window: &mut Option<&mut Window>, cx: &mut App| {
1759                    any_entity
1760                        .downcast::<T>()
1761                        .unwrap()
1762                        .update(cx, |entity_state, cx| {
1763                            on_new(entity_state, window.as_deref_mut(), cx)
1764                        })
1765                },
1766            ),
1767        )
1768    }
1769
1770    /// Observe the release of a entity. The callback is invoked after the entity
1771    /// has no more strong references but before it has been dropped.
1772    pub fn observe_release<T>(
1773        &self,
1774        handle: &Entity<T>,
1775        on_release: impl FnOnce(&mut T, &mut App) + 'static,
1776    ) -> Subscription
1777    where
1778        T: 'static,
1779    {
1780        let (subscription, activate) = self.release_listeners.insert(
1781            handle.entity_id(),
1782            Box::new(move |entity, cx| {
1783                let entity = entity.downcast_mut().expect("invalid entity type");
1784                on_release(entity, cx)
1785            }),
1786        );
1787        activate();
1788        subscription
1789    }
1790
1791    /// Observe the release of a entity. The callback is invoked after the entity
1792    /// has no more strong references but before it has been dropped.
1793    pub fn observe_release_in<T>(
1794        &self,
1795        handle: &Entity<T>,
1796        window: &Window,
1797        on_release: impl FnOnce(&mut T, &mut Window, &mut App) + 'static,
1798    ) -> Subscription
1799    where
1800        T: 'static,
1801    {
1802        let window_handle = window.handle;
1803        self.observe_release(handle, move |entity, cx| {
1804            let _ = window_handle.update(cx, |_, window, cx| on_release(entity, window, cx));
1805        })
1806    }
1807
1808    /// Register a callback to be invoked when a keystroke is received by the application
1809    /// in any window. Note that this fires after all other action and event mechanisms have resolved
1810    /// and that this API will not be invoked if the event's propagation is stopped.
1811    pub fn observe_keystrokes(
1812        &mut self,
1813        mut f: impl FnMut(&KeystrokeEvent, &mut Window, &mut App) + 'static,
1814    ) -> Subscription {
1815        fn inner(
1816            keystroke_observers: &SubscriberSet<(), KeystrokeObserver>,
1817            handler: KeystrokeObserver,
1818        ) -> Subscription {
1819            let (subscription, activate) = keystroke_observers.insert((), handler);
1820            activate();
1821            subscription
1822        }
1823
1824        inner(
1825            &self.keystroke_observers,
1826            Box::new(move |event, window, cx| {
1827                f(event, window, cx);
1828                true
1829            }),
1830        )
1831    }
1832
1833    /// Register a callback to be invoked when a keystroke is received by the application
1834    /// in any window. Note that this fires _before_ all other action and event mechanisms have resolved
1835    /// unlike [`App::observe_keystrokes`] which fires after. This means that `cx.stop_propagation` calls
1836    /// within interceptors will prevent action dispatch
1837    pub fn intercept_keystrokes(
1838        &mut self,
1839        mut f: impl FnMut(&KeystrokeEvent, &mut Window, &mut App) + 'static,
1840    ) -> Subscription {
1841        fn inner(
1842            keystroke_interceptors: &SubscriberSet<(), KeystrokeObserver>,
1843            handler: KeystrokeObserver,
1844        ) -> Subscription {
1845            let (subscription, activate) = keystroke_interceptors.insert((), handler);
1846            activate();
1847            subscription
1848        }
1849
1850        inner(
1851            &self.keystroke_interceptors,
1852            Box::new(move |event, window, cx| {
1853                f(event, window, cx);
1854                true
1855            }),
1856        )
1857    }
1858
1859    /// Register key bindings.
1860    pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
1861        self.keymap.borrow_mut().add_bindings(bindings);
1862        self.pending_effects.push_back(Effect::RefreshWindows);
1863    }
1864
1865    /// Clear all key bindings in the app.
1866    pub fn clear_key_bindings(&mut self) {
1867        self.keymap.borrow_mut().clear();
1868        self.pending_effects.push_back(Effect::RefreshWindows);
1869    }
1870
1871    /// Get all key bindings in the app.
1872    pub fn key_bindings(&self) -> Rc<RefCell<Keymap>> {
1873        self.keymap.clone()
1874    }
1875
1876    /// Register a global handler for actions invoked via the keyboard. These handlers are run at
1877    /// the end of the bubble phase for actions, and so will only be invoked if there are no other
1878    /// handlers or if they called `cx.propagate()`.
1879    pub fn on_action<A: Action>(
1880        &mut self,
1881        listener: impl Fn(&A, &mut Self) + 'static,
1882    ) -> &mut Self {
1883        self.global_action_listeners
1884            .entry(TypeId::of::<A>())
1885            .or_default()
1886            .push(Rc::new(move |action, phase, cx| {
1887                if phase == DispatchPhase::Bubble {
1888                    let action = action.downcast_ref().unwrap();
1889                    listener(action, cx)
1890                }
1891            }));
1892        self
1893    }
1894
1895    /// Event handlers propagate events by default. Call this method to stop dispatching to
1896    /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
1897    /// the opposite of [`Self::propagate`]. It's also possible to cancel a call to [`Self::propagate`] by
1898    /// calling this method before effects are flushed.
1899    pub fn stop_propagation(&mut self) {
1900        self.propagate_event = false;
1901    }
1902
1903    /// Action handlers stop propagation by default during the bubble phase of action dispatch
1904    /// dispatching to action handlers higher in the element tree. This is the opposite of
1905    /// [`Self::stop_propagation`]. It's also possible to cancel a call to [`Self::stop_propagation`] by calling
1906    /// this method before effects are flushed.
1907    pub fn propagate(&mut self) {
1908        self.propagate_event = true;
1909    }
1910
1911    /// Build an action from some arbitrary data, typically a keymap entry.
1912    pub fn build_action(
1913        &self,
1914        name: &str,
1915        data: Option<serde_json::Value>,
1916    ) -> std::result::Result<Box<dyn Action>, ActionBuildError> {
1917        self.actions.build_action(name, data)
1918    }
1919
1920    /// Get all action names that have been registered. Note that registration only allows for
1921    /// actions to be built dynamically, and is unrelated to binding actions in the element tree.
1922    pub fn all_action_names(&self) -> &[&'static str] {
1923        self.actions.all_action_names()
1924    }
1925
1926    /// Returns key bindings that invoke the given action on the currently focused element, without
1927    /// checking context. Bindings are returned in the order they were added. For display, the last
1928    /// binding should take precedence.
1929    pub fn all_bindings_for_input(&self, input: &[Keystroke]) -> Vec<KeyBinding> {
1930        RefCell::borrow(&self.keymap).all_bindings_for_input(input)
1931    }
1932
1933    /// Get all non-internal actions that have been registered, along with their schemas.
1934    pub fn action_schemas(
1935        &self,
1936        generator: &mut schemars::SchemaGenerator,
1937    ) -> Vec<(&'static str, Option<schemars::Schema>)> {
1938        self.actions.action_schemas(generator)
1939    }
1940
1941    /// Get the schema for a specific action by name.
1942    /// Returns `None` if the action is not found.
1943    /// Returns `Some(None)` if the action exists but has no schema.
1944    /// Returns `Some(Some(schema))` if the action exists and has a schema.
1945    pub fn action_schema_by_name(
1946        &self,
1947        name: &str,
1948        generator: &mut schemars::SchemaGenerator,
1949    ) -> Option<Option<schemars::Schema>> {
1950        self.actions.action_schema_by_name(name, generator)
1951    }
1952
1953    /// Get a map from a deprecated action name to the canonical name.
1954    pub fn deprecated_actions_to_preferred_actions(&self) -> &HashMap<&'static str, &'static str> {
1955        self.actions.deprecated_aliases()
1956    }
1957
1958    /// Get a map from an action name to the deprecation messages.
1959    pub fn action_deprecation_messages(&self) -> &HashMap<&'static str, &'static str> {
1960        self.actions.deprecation_messages()
1961    }
1962
1963    /// Get a map from an action name to the documentation.
1964    pub fn action_documentation(&self) -> &HashMap<&'static str, &'static str> {
1965        self.actions.documentation()
1966    }
1967
1968    /// Register a callback to be invoked when the application is about to quit.
1969    /// It is not possible to cancel the quit event at this point.
1970    pub fn on_app_quit<Fut>(
1971        &self,
1972        mut on_quit: impl FnMut(&mut App) -> Fut + 'static,
1973    ) -> Subscription
1974    where
1975        Fut: 'static + Future<Output = ()>,
1976    {
1977        let (subscription, activate) = self.quit_observers.insert(
1978            (),
1979            Box::new(move |cx| {
1980                let future = on_quit(cx);
1981                future.boxed_local()
1982            }),
1983        );
1984        activate();
1985        subscription
1986    }
1987
1988    /// Register a callback to be invoked when the application is about to restart.
1989    ///
1990    /// These callbacks are called before any `on_app_quit` callbacks.
1991    pub fn on_app_restart(&self, mut on_restart: impl 'static + FnMut(&mut App)) -> Subscription {
1992        let (subscription, activate) = self.restart_observers.insert(
1993            (),
1994            Box::new(move |cx| {
1995                on_restart(cx);
1996                true
1997            }),
1998        );
1999        activate();
2000        subscription
2001    }
2002
2003    /// Register a callback to be invoked when a window is closed
2004    /// The window is no longer accessible at the point this callback is invoked.
2005    pub fn on_window_closed(&self, mut on_closed: impl FnMut(&mut App) + 'static) -> Subscription {
2006        let (subscription, activate) = self.window_closed_observers.insert((), Box::new(on_closed));
2007        activate();
2008        subscription
2009    }
2010
2011    pub(crate) fn clear_pending_keystrokes(&mut self) {
2012        for window in self.windows() {
2013            window
2014                .update(self, |_, window, cx| {
2015                    if window.pending_input_keystrokes().is_some() {
2016                        window.clear_pending_keystrokes();
2017                        window.pending_input_changed(cx);
2018                    }
2019                })
2020                .ok();
2021        }
2022    }
2023
2024    /// Checks if the given action is bound in the current context, as defined by the app's current focus,
2025    /// the bindings in the element tree, and any global action listeners.
2026    pub fn is_action_available(&mut self, action: &dyn Action) -> bool {
2027        let mut action_available = false;
2028        if let Some(window) = self.active_window()
2029            && let Ok(window_action_available) =
2030                window.update(self, |_, window, cx| window.is_action_available(action, cx))
2031        {
2032            action_available = window_action_available;
2033        }
2034
2035        action_available
2036            || self
2037                .global_action_listeners
2038                .contains_key(&action.as_any().type_id())
2039    }
2040
2041    /// Sets the menu bar for this application. This will replace any existing menu bar.
2042    pub fn set_menus(&self, menus: Vec<Menu>) {
2043        self.platform.set_menus(menus, &self.keymap.borrow());
2044    }
2045
2046    /// Gets the menu bar for this application.
2047    pub fn get_menus(&self) -> Option<Vec<OwnedMenu>> {
2048        self.platform.get_menus()
2049    }
2050
2051    /// Sets the right click menu for the app icon in the dock
2052    pub fn set_dock_menu(&self, menus: Vec<MenuItem>) {
2053        self.platform.set_dock_menu(menus, &self.keymap.borrow())
2054    }
2055
2056    /// Performs the action associated with the given dock menu item, only used on Windows for now.
2057    pub fn perform_dock_menu_action(&self, action: usize) {
2058        self.platform.perform_dock_menu_action(action);
2059    }
2060
2061    /// Adds given path to the bottom of the list of recent paths for the application.
2062    /// The list is usually shown on the application icon's context menu in the dock,
2063    /// and allows to open the recent files via that context menu.
2064    /// If the path is already in the list, it will be moved to the bottom of the list.
2065    pub fn add_recent_document(&self, path: &Path) {
2066        self.platform.add_recent_document(path);
2067    }
2068
2069    /// Updates the jump list with the updated list of recent paths for the application, only used on Windows for now.
2070    /// Note that this also sets the dock menu on Windows.
2071    pub fn update_jump_list(
2072        &self,
2073        menus: Vec<MenuItem>,
2074        entries: Vec<SmallVec<[PathBuf; 2]>>,
2075    ) -> Task<Vec<SmallVec<[PathBuf; 2]>>> {
2076        self.platform.update_jump_list(menus, entries)
2077    }
2078
2079    /// Dispatch an action to the currently active window or global action handler
2080    /// See [`crate::Action`] for more information on how actions work
2081    pub fn dispatch_action(&mut self, action: &dyn Action) {
2082        if let Some(active_window) = self.active_window() {
2083            active_window
2084                .update(self, |_, window, cx| {
2085                    window.dispatch_action(action.boxed_clone(), cx)
2086                })
2087                .log_err();
2088        } else {
2089            self.dispatch_global_action(action);
2090        }
2091    }
2092
2093    fn dispatch_global_action(&mut self, action: &dyn Action) {
2094        self.propagate_event = true;
2095
2096        if let Some(mut global_listeners) = self
2097            .global_action_listeners
2098            .remove(&action.as_any().type_id())
2099        {
2100            for listener in &global_listeners {
2101                listener(action.as_any(), DispatchPhase::Capture, self);
2102                if !self.propagate_event {
2103                    break;
2104                }
2105            }
2106
2107            global_listeners.extend(
2108                self.global_action_listeners
2109                    .remove(&action.as_any().type_id())
2110                    .unwrap_or_default(),
2111            );
2112
2113            self.global_action_listeners
2114                .insert(action.as_any().type_id(), global_listeners);
2115        }
2116
2117        if self.propagate_event
2118            && let Some(mut global_listeners) = self
2119                .global_action_listeners
2120                .remove(&action.as_any().type_id())
2121        {
2122            for listener in global_listeners.iter().rev() {
2123                listener(action.as_any(), DispatchPhase::Bubble, self);
2124                if !self.propagate_event {
2125                    break;
2126                }
2127            }
2128
2129            global_listeners.extend(
2130                self.global_action_listeners
2131                    .remove(&action.as_any().type_id())
2132                    .unwrap_or_default(),
2133            );
2134
2135            self.global_action_listeners
2136                .insert(action.as_any().type_id(), global_listeners);
2137        }
2138    }
2139
2140    /// Is there currently something being dragged?
2141    pub fn has_active_drag(&self) -> bool {
2142        self.active_drag.is_some()
2143    }
2144
2145    /// Gets the cursor style of the currently active drag operation.
2146    pub fn active_drag_cursor_style(&self) -> Option<CursorStyle> {
2147        self.active_drag.as_ref().and_then(|drag| drag.cursor_style)
2148    }
2149
2150    /// Stops active drag and clears any related effects.
2151    pub fn stop_active_drag(&mut self, window: &mut Window) -> bool {
2152        if self.active_drag.is_some() {
2153            self.active_drag = None;
2154            window.refresh();
2155            true
2156        } else {
2157            false
2158        }
2159    }
2160
2161    /// Sets the cursor style for the currently active drag operation.
2162    pub fn set_active_drag_cursor_style(
2163        &mut self,
2164        cursor_style: CursorStyle,
2165        window: &mut Window,
2166    ) -> bool {
2167        if let Some(ref mut drag) = self.active_drag {
2168            drag.cursor_style = Some(cursor_style);
2169            window.refresh();
2170            true
2171        } else {
2172            false
2173        }
2174    }
2175
2176    /// Set the prompt renderer for GPUI. This will replace the default or platform specific
2177    /// prompts with this custom implementation.
2178    pub fn set_prompt_builder(
2179        &mut self,
2180        renderer: impl Fn(
2181            PromptLevel,
2182            &str,
2183            Option<&str>,
2184            &[PromptButton],
2185            PromptHandle,
2186            &mut Window,
2187            &mut App,
2188        ) -> RenderablePromptHandle
2189        + 'static,
2190    ) {
2191        self.prompt_builder = Some(PromptBuilder::Custom(Box::new(renderer)));
2192    }
2193
2194    /// Reset the prompt builder to the default implementation.
2195    pub fn reset_prompt_builder(&mut self) {
2196        self.prompt_builder = Some(PromptBuilder::Default);
2197    }
2198
2199    /// Remove an asset from GPUI's cache
2200    pub fn remove_asset<A: Asset>(&mut self, source: &A::Source) {
2201        let asset_id = (TypeId::of::<A>(), hash(source));
2202        self.loading_assets.remove(&asset_id);
2203    }
2204
2205    /// Asynchronously load an asset, if the asset hasn't finished loading this will return None.
2206    ///
2207    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
2208    /// time, and the results of this call will be cached
2209    pub fn fetch_asset<A: Asset>(&mut self, source: &A::Source) -> (Shared<Task<A::Output>>, bool) {
2210        let asset_id = (TypeId::of::<A>(), hash(source));
2211        let mut is_first = false;
2212        let task = self
2213            .loading_assets
2214            .remove(&asset_id)
2215            .map(|boxed_task| *boxed_task.downcast::<Shared<Task<A::Output>>>().unwrap())
2216            .unwrap_or_else(|| {
2217                is_first = true;
2218                let future = A::load(source.clone(), self);
2219
2220                self.background_executor().spawn(future).shared()
2221            });
2222
2223        self.loading_assets.insert(asset_id, Box::new(task.clone()));
2224
2225        (task, is_first)
2226    }
2227
2228    /// Obtain a new [`FocusHandle`], which allows you to track and manipulate the keyboard focus
2229    /// for elements rendered within this window.
2230    #[track_caller]
2231    pub fn focus_handle(&self) -> FocusHandle {
2232        FocusHandle::new(&self.focus_handles)
2233    }
2234
2235    /// Tell GPUI that an entity has changed and observers of it should be notified.
2236    pub fn notify(&mut self, entity_id: EntityId) {
2237        let window_invalidators = mem::take(
2238            self.window_invalidators_by_entity
2239                .entry(entity_id)
2240                .or_default(),
2241        );
2242
2243        if window_invalidators.is_empty() {
2244            if self.pending_notifications.insert(entity_id) {
2245                self.pending_effects
2246                    .push_back(Effect::Notify { emitter: entity_id });
2247            }
2248        } else {
2249            for invalidator in window_invalidators.values() {
2250                invalidator.invalidate_view(entity_id, self);
2251            }
2252        }
2253
2254        self.window_invalidators_by_entity
2255            .insert(entity_id, window_invalidators);
2256    }
2257
2258    /// Returns the name for this [`App`].
2259    #[cfg(any(test, feature = "test-support", debug_assertions))]
2260    pub fn get_name(&self) -> Option<&'static str> {
2261        self.name
2262    }
2263
2264    /// Returns `true` if the platform file picker supports selecting a mix of files and directories.
2265    pub fn can_select_mixed_files_and_dirs(&self) -> bool {
2266        self.platform.can_select_mixed_files_and_dirs()
2267    }
2268
2269    /// Removes an image from the sprite atlas on all windows.
2270    ///
2271    /// If the current window is being updated, it will be removed from `App.windows`, you can use `current_window` to specify the current window.
2272    /// This is a no-op if the image is not in the sprite atlas.
2273    pub fn drop_image(&mut self, image: Arc<RenderImage>, current_window: Option<&mut Window>) {
2274        // remove the texture from all other windows
2275        for window in self.windows.values_mut().flatten() {
2276            _ = window.drop_image(image.clone());
2277        }
2278
2279        // remove the texture from the current window
2280        if let Some(window) = current_window {
2281            _ = window.drop_image(image);
2282        }
2283    }
2284
2285    /// Sets the renderer for the inspector.
2286    #[cfg(any(feature = "inspector", debug_assertions))]
2287    pub fn set_inspector_renderer(&mut self, f: crate::InspectorRenderer) {
2288        self.inspector_renderer = Some(f);
2289    }
2290
2291    /// Registers a renderer specific to an inspector state.
2292    #[cfg(any(feature = "inspector", debug_assertions))]
2293    pub fn register_inspector_element<T: 'static, R: crate::IntoElement>(
2294        &mut self,
2295        f: impl 'static + Fn(crate::InspectorElementId, &T, &mut Window, &mut App) -> R,
2296    ) {
2297        self.inspector_element_registry.register(f);
2298    }
2299
2300    /// Initializes gpui's default colors for the application.
2301    ///
2302    /// These colors can be accessed through `cx.default_colors()`.
2303    pub fn init_colors(&mut self) {
2304        self.set_global(GlobalColors(Arc::new(Colors::default())));
2305    }
2306}
2307
2308impl AppContext for App {
2309    /// Builds an entity that is owned by the application.
2310    ///
2311    /// The given function will be invoked with a [`Context`] and must return an object representing the entity. An
2312    /// [`Entity`] handle will be returned, which can be used to access the entity in a context.
2313    fn new<T: 'static>(&mut self, build_entity: impl FnOnce(&mut Context<T>) -> T) -> Entity<T> {
2314        self.update(|cx| {
2315            let slot = cx.entities.reserve();
2316            let handle = slot.clone();
2317            let entity = build_entity(&mut Context::new_context(cx, slot.downgrade()));
2318
2319            cx.push_effect(Effect::EntityCreated {
2320                entity: handle.clone().into_any(),
2321                tid: TypeId::of::<T>(),
2322                window: cx.window_update_stack.last().cloned(),
2323            });
2324
2325            cx.entities.insert(slot, entity);
2326            handle
2327        })
2328    }
2329
2330    fn reserve_entity<T: 'static>(&mut self) -> Reservation<T> {
2331        Reservation(self.entities.reserve())
2332    }
2333
2334    fn insert_entity<T: 'static>(
2335        &mut self,
2336        reservation: Reservation<T>,
2337        build_entity: impl FnOnce(&mut Context<T>) -> T,
2338    ) -> Entity<T> {
2339        self.update(|cx| {
2340            let slot = reservation.0;
2341            let entity = build_entity(&mut Context::new_context(cx, slot.downgrade()));
2342            cx.entities.insert(slot, entity)
2343        })
2344    }
2345
2346    /// Updates the entity referenced by the given handle. The function is passed a mutable reference to the
2347    /// entity along with a `Context` for the entity.
2348    fn update_entity<T: 'static, R>(
2349        &mut self,
2350        handle: &Entity<T>,
2351        update: impl FnOnce(&mut T, &mut Context<T>) -> R,
2352    ) -> R {
2353        self.update(|cx| {
2354            let mut entity = cx.entities.lease(handle);
2355            let result = update(
2356                &mut entity,
2357                &mut Context::new_context(cx, handle.downgrade()),
2358            );
2359            cx.entities.end_lease(entity);
2360            result
2361        })
2362    }
2363
2364    fn as_mut<'a, T>(&'a mut self, handle: &Entity<T>) -> GpuiBorrow<'a, T>
2365    where
2366        T: 'static,
2367    {
2368        GpuiBorrow::new(handle.clone(), self)
2369    }
2370
2371    fn read_entity<T, R>(&self, handle: &Entity<T>, read: impl FnOnce(&T, &App) -> R) -> R
2372    where
2373        T: 'static,
2374    {
2375        let entity = self.entities.read(handle);
2376        read(entity, self)
2377    }
2378
2379    fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
2380    where
2381        F: FnOnce(AnyView, &mut Window, &mut App) -> T,
2382    {
2383        self.update_window_id(handle.id, update)
2384    }
2385
2386    fn read_window<T, R>(
2387        &self,
2388        window: &WindowHandle<T>,
2389        read: impl FnOnce(Entity<T>, &App) -> R,
2390    ) -> Result<R>
2391    where
2392        T: 'static,
2393    {
2394        let window = self
2395            .windows
2396            .get(window.id)
2397            .context("window not found")?
2398            .as_deref()
2399            .expect("attempted to read a window that is already on the stack");
2400
2401        let root_view = window.root.clone().unwrap();
2402        let view = root_view
2403            .downcast::<T>()
2404            .map_err(|_| anyhow!("root view's type has changed"))?;
2405
2406        Ok(read(view, self))
2407    }
2408
2409    fn background_spawn<R>(&self, future: impl Future<Output = R> + Send + 'static) -> Task<R>
2410    where
2411        R: Send + 'static,
2412    {
2413        self.background_executor.spawn(future)
2414    }
2415
2416    fn read_global<G, R>(&self, callback: impl FnOnce(&G, &App) -> R) -> R
2417    where
2418        G: Global,
2419    {
2420        let mut g = self.global::<G>();
2421        callback(g, self)
2422    }
2423}
2424
2425/// These effects are processed at the end of each application update cycle.
2426pub(crate) enum Effect {
2427    Notify {
2428        emitter: EntityId,
2429    },
2430    Emit {
2431        emitter: EntityId,
2432        event_type: TypeId,
2433        event: ArenaBox<dyn Any>,
2434    },
2435    RefreshWindows,
2436    NotifyGlobalObservers {
2437        global_type: TypeId,
2438    },
2439    Defer {
2440        callback: Box<dyn FnOnce(&mut App) + 'static>,
2441    },
2442    EntityCreated {
2443        entity: AnyEntity,
2444        tid: TypeId,
2445        window: Option<WindowId>,
2446    },
2447}
2448
2449impl std::fmt::Debug for Effect {
2450    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
2451        match self {
2452            Effect::Notify { emitter } => write!(f, "Notify({})", emitter),
2453            Effect::Emit { emitter, .. } => write!(f, "Emit({:?})", emitter),
2454            Effect::RefreshWindows => write!(f, "RefreshWindows"),
2455            Effect::NotifyGlobalObservers { global_type } => {
2456                write!(f, "NotifyGlobalObservers({:?})", global_type)
2457            }
2458            Effect::Defer { .. } => write!(f, "Defer(..)"),
2459            Effect::EntityCreated { entity, .. } => write!(f, "EntityCreated({:?})", entity),
2460        }
2461    }
2462}
2463
2464/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
2465pub(crate) struct GlobalLease<G: Global> {
2466    global: Box<dyn Any>,
2467    global_type: PhantomData<G>,
2468}
2469
2470impl<G: Global> GlobalLease<G> {
2471    fn new(global: Box<dyn Any>) -> Self {
2472        GlobalLease {
2473            global,
2474            global_type: PhantomData,
2475        }
2476    }
2477}
2478
2479impl<G: Global> Deref for GlobalLease<G> {
2480    type Target = G;
2481
2482    fn deref(&self) -> &Self::Target {
2483        self.global.downcast_ref().unwrap()
2484    }
2485}
2486
2487impl<G: Global> DerefMut for GlobalLease<G> {
2488    fn deref_mut(&mut self) -> &mut Self::Target {
2489        self.global.downcast_mut().unwrap()
2490    }
2491}
2492
2493/// Contains state associated with an active drag operation, started by dragging an element
2494/// within the window or by dragging into the app from the underlying platform.
2495pub struct AnyDrag {
2496    /// The view used to render this drag
2497    pub view: AnyView,
2498
2499    /// The value of the dragged item, to be dropped
2500    pub value: Arc<dyn Any>,
2501
2502    /// This is used to render the dragged item in the same place
2503    /// on the original element that the drag was initiated
2504    pub cursor_offset: Point<Pixels>,
2505
2506    /// The cursor style to use while dragging
2507    pub cursor_style: Option<CursorStyle>,
2508}
2509
2510/// Contains state associated with a tooltip. You'll only need this struct if you're implementing
2511/// tooltip behavior on a custom element. Otherwise, use [Div::tooltip](crate::Interactivity::tooltip).
2512#[derive(Clone)]
2513pub struct AnyTooltip {
2514    /// The view used to display the tooltip
2515    pub view: AnyView,
2516
2517    /// The absolute position of the mouse when the tooltip was deployed.
2518    pub mouse_position: Point<Pixels>,
2519
2520    /// Given the bounds of the tooltip, checks whether the tooltip should still be visible and
2521    /// updates its state accordingly. This is needed atop the hovered element's mouse move handler
2522    /// to handle the case where the element is not painted (e.g. via use of `visible_on_hover`).
2523    pub check_visible_and_update: Rc<dyn Fn(Bounds<Pixels>, &mut Window, &mut App) -> bool>,
2524}
2525
2526/// A keystroke event, and potentially the associated action
2527#[derive(Debug)]
2528pub struct KeystrokeEvent {
2529    /// The keystroke that occurred
2530    pub keystroke: Keystroke,
2531
2532    /// The action that was resolved for the keystroke, if any
2533    pub action: Option<Box<dyn Action>>,
2534
2535    /// The context stack at the time
2536    pub context_stack: Vec<KeyContext>,
2537}
2538
2539struct NullHttpClient;
2540
2541impl HttpClient for NullHttpClient {
2542    fn send(
2543        &self,
2544        _req: http_client::Request<http_client::AsyncBody>,
2545    ) -> futures::future::BoxFuture<
2546        'static,
2547        anyhow::Result<http_client::Response<http_client::AsyncBody>>,
2548    > {
2549        async move {
2550            anyhow::bail!("No HttpClient available");
2551        }
2552        .boxed()
2553    }
2554
2555    fn user_agent(&self) -> Option<&http_client::http::HeaderValue> {
2556        None
2557    }
2558
2559    fn proxy(&self) -> Option<&Url> {
2560        None
2561    }
2562}
2563
2564/// A mutable reference to an entity owned by GPUI
2565pub struct GpuiBorrow<'a, T> {
2566    inner: Option<Lease<T>>,
2567    app: &'a mut App,
2568}
2569
2570impl<'a, T: 'static> GpuiBorrow<'a, T> {
2571    fn new(inner: Entity<T>, app: &'a mut App) -> Self {
2572        app.start_update();
2573        let lease = app.entities.lease(&inner);
2574        Self {
2575            inner: Some(lease),
2576            app,
2577        }
2578    }
2579}
2580
2581impl<'a, T: 'static> std::borrow::Borrow<T> for GpuiBorrow<'a, T> {
2582    fn borrow(&self) -> &T {
2583        self.inner.as_ref().unwrap().borrow()
2584    }
2585}
2586
2587impl<'a, T: 'static> std::borrow::BorrowMut<T> for GpuiBorrow<'a, T> {
2588    fn borrow_mut(&mut self) -> &mut T {
2589        self.inner.as_mut().unwrap().borrow_mut()
2590    }
2591}
2592
2593impl<'a, T: 'static> std::ops::Deref for GpuiBorrow<'a, T> {
2594    type Target = T;
2595
2596    fn deref(&self) -> &Self::Target {
2597        self.inner.as_ref().unwrap()
2598    }
2599}
2600
2601impl<'a, T: 'static> std::ops::DerefMut for GpuiBorrow<'a, T> {
2602    fn deref_mut(&mut self) -> &mut T {
2603        self.inner.as_mut().unwrap()
2604    }
2605}
2606
2607impl<'a, T> Drop for GpuiBorrow<'a, T> {
2608    fn drop(&mut self) {
2609        let lease = self.inner.take().unwrap();
2610        self.app.notify(lease.id);
2611        self.app.entities.end_lease(lease);
2612        self.app.finish_update();
2613    }
2614}
2615
2616impl Drop for App {
2617    fn drop(&mut self) {
2618        self.foreground_executor.close();
2619        self.background_executor.close();
2620    }
2621}
2622
2623#[cfg(test)]
2624mod test {
2625    use std::{cell::RefCell, rc::Rc};
2626
2627    use crate::{AppContext, TestAppContext};
2628
2629    #[test]
2630    fn test_gpui_borrow() {
2631        let cx = TestAppContext::single();
2632        let observation_count = Rc::new(RefCell::new(0));
2633
2634        let state = cx.update(|cx| {
2635            let state = cx.new(|_| false);
2636            cx.observe(&state, {
2637                let observation_count = observation_count.clone();
2638                move |_, _| {
2639                    let mut count = observation_count.borrow_mut();
2640                    *count += 1;
2641                }
2642            })
2643            .detach();
2644
2645            state
2646        });
2647
2648        cx.update(|cx| {
2649            // Calling this like this so that we don't clobber the borrow_mut above
2650            *std::borrow::BorrowMut::borrow_mut(&mut state.as_mut(cx)) = true;
2651        });
2652
2653        cx.update(|cx| {
2654            state.write(cx, false);
2655        });
2656
2657        assert_eq!(*observation_count.borrow(), 2);
2658    }
2659}