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 = Rc::downgrade(&app);
 748            move || {
 749                if let Some(cx) = cx.upgrade() {
 750                    cx.borrow_mut().shutdown();
 751                }
 752            }
 753        }));
 754
 755        app
 756    }
 757
 758    #[doc(hidden)]
 759    pub fn ref_counts_drop_handle(&self) -> impl Sized + use<> {
 760        self.entities.ref_counts_drop_handle()
 761    }
 762
 763    /// Captures a snapshot of all entities that currently have alive handles.
 764    ///
 765    /// The returned [`LeakDetectorSnapshot`] can later be passed to
 766    /// [`assert_no_new_leaks`](Self::assert_no_new_leaks) to verify that no
 767    /// entities created after the snapshot are still alive.
 768    #[cfg(any(test, feature = "leak-detection"))]
 769    pub fn leak_detector_snapshot(&self) -> LeakDetectorSnapshot {
 770        self.entities.leak_detector_snapshot()
 771    }
 772
 773    /// Asserts that no entities created after `snapshot` still have alive handles.
 774    ///
 775    /// Entities that were already tracked at the time of the snapshot are ignored,
 776    /// even if they still have handles. Only *new* entities (those whose
 777    /// `EntityId` was not present in the snapshot) are considered leaks.
 778    ///
 779    /// # Panics
 780    ///
 781    /// Panics if any new entity handles exist. The panic message lists every
 782    /// leaked entity with its type name, and includes allocation-site backtraces
 783    /// when `LEAK_BACKTRACE` is set.
 784    #[cfg(any(test, feature = "leak-detection"))]
 785    pub fn assert_no_new_leaks(&self, snapshot: &LeakDetectorSnapshot) {
 786        self.entities.assert_no_new_leaks(snapshot)
 787    }
 788
 789    /// Quit the application gracefully. Handlers registered with [`Context::on_app_quit`]
 790    /// will be given 100ms to complete before exiting.
 791    pub fn shutdown(&mut self) {
 792        let mut futures = Vec::new();
 793
 794        for observer in self.quit_observers.remove(&()) {
 795            futures.push(observer(self));
 796        }
 797
 798        self.windows.clear();
 799        self.window_handles.clear();
 800        self.flush_effects();
 801        self.quitting = true;
 802
 803        let futures = futures::future::join_all(futures);
 804        if self
 805            .foreground_executor
 806            .block_with_timeout(SHUTDOWN_TIMEOUT, futures)
 807            .is_err()
 808        {
 809            log::error!("timed out waiting on app_will_quit");
 810        }
 811
 812        self.quitting = false;
 813    }
 814
 815    /// Get the id of the current keyboard layout
 816    pub fn keyboard_layout(&self) -> &dyn PlatformKeyboardLayout {
 817        self.keyboard_layout.as_ref()
 818    }
 819
 820    /// Get the current keyboard mapper.
 821    pub fn keyboard_mapper(&self) -> &Rc<dyn PlatformKeyboardMapper> {
 822        &self.keyboard_mapper
 823    }
 824
 825    /// Invokes a handler when the current keyboard layout changes
 826    pub fn on_keyboard_layout_change<F>(&self, mut callback: F) -> Subscription
 827    where
 828        F: 'static + FnMut(&mut App),
 829    {
 830        let (subscription, activate) = self.keyboard_layout_observers.insert(
 831            (),
 832            Box::new(move |cx| {
 833                callback(cx);
 834                true
 835            }),
 836        );
 837        activate();
 838        subscription
 839    }
 840
 841    /// Gracefully quit the application via the platform's standard routine.
 842    pub fn quit(&self) {
 843        self.platform.quit();
 844    }
 845
 846    /// Schedules all windows in the application to be redrawn. This can be called
 847    /// multiple times in an update cycle and still result in a single redraw.
 848    pub fn refresh_windows(&mut self) {
 849        self.pending_effects.push_back(Effect::RefreshWindows);
 850    }
 851
 852    pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
 853        self.start_update();
 854        let result = update(self);
 855        self.finish_update();
 856        result
 857    }
 858
 859    pub(crate) fn start_update(&mut self) {
 860        self.pending_updates += 1;
 861    }
 862
 863    pub(crate) fn finish_update(&mut self) {
 864        if !self.flushing_effects && self.pending_updates == 1 {
 865            self.flushing_effects = true;
 866            self.flush_effects();
 867            self.flushing_effects = false;
 868        }
 869        self.pending_updates -= 1;
 870    }
 871
 872    /// Arrange a callback to be invoked when the given entity calls `notify` on its respective context.
 873    pub fn observe<W>(
 874        &mut self,
 875        entity: &Entity<W>,
 876        mut on_notify: impl FnMut(Entity<W>, &mut App) + 'static,
 877    ) -> Subscription
 878    where
 879        W: 'static,
 880    {
 881        self.observe_internal(entity, move |e, cx| {
 882            on_notify(e, cx);
 883            true
 884        })
 885    }
 886
 887    pub(crate) fn detect_accessed_entities<R>(
 888        &mut self,
 889        callback: impl FnOnce(&mut App) -> R,
 890    ) -> (R, FxHashSet<EntityId>) {
 891        let accessed_entities_start = self.entities.accessed_entities.get_mut().clone();
 892        let result = callback(self);
 893        let entities_accessed_in_callback = self
 894            .entities
 895            .accessed_entities
 896            .get_mut()
 897            .difference(&accessed_entities_start)
 898            .copied()
 899            .collect::<FxHashSet<EntityId>>();
 900        (result, entities_accessed_in_callback)
 901    }
 902
 903    pub(crate) fn record_entities_accessed(
 904        &mut self,
 905        window_handle: AnyWindowHandle,
 906        invalidator: WindowInvalidator,
 907        entities: &FxHashSet<EntityId>,
 908    ) {
 909        let mut tracked_entities =
 910            std::mem::take(self.tracked_entities.entry(window_handle.id).or_default());
 911        for entity in tracked_entities.iter() {
 912            self.window_invalidators_by_entity
 913                .entry(*entity)
 914                .and_modify(|windows| {
 915                    windows.remove(&window_handle.id);
 916                });
 917        }
 918        for entity in entities.iter() {
 919            self.window_invalidators_by_entity
 920                .entry(*entity)
 921                .or_default()
 922                .insert(window_handle.id, invalidator.clone());
 923        }
 924        tracked_entities.clear();
 925        tracked_entities.extend(entities.iter().copied());
 926        self.tracked_entities
 927            .insert(window_handle.id, tracked_entities);
 928    }
 929
 930    pub(crate) fn new_observer(&mut self, key: EntityId, value: Handler) -> Subscription {
 931        let (subscription, activate) = self.observers.insert(key, value);
 932        self.defer(move |_| activate());
 933        subscription
 934    }
 935
 936    pub(crate) fn observe_internal<W>(
 937        &mut self,
 938        entity: &Entity<W>,
 939        mut on_notify: impl FnMut(Entity<W>, &mut App) -> bool + 'static,
 940    ) -> Subscription
 941    where
 942        W: 'static,
 943    {
 944        let entity_id = entity.entity_id();
 945        let handle = entity.downgrade();
 946        self.new_observer(
 947            entity_id,
 948            Box::new(move |cx| {
 949                if let Some(entity) = handle.upgrade() {
 950                    on_notify(entity, cx)
 951                } else {
 952                    false
 953                }
 954            }),
 955        )
 956    }
 957
 958    /// Arrange for the given callback to be invoked whenever the given entity emits an event of a given type.
 959    /// The callback is provided a handle to the emitting entity and a reference to the emitted event.
 960    pub fn subscribe<T, Event>(
 961        &mut self,
 962        entity: &Entity<T>,
 963        mut on_event: impl FnMut(Entity<T>, &Event, &mut App) + 'static,
 964    ) -> Subscription
 965    where
 966        T: 'static + EventEmitter<Event>,
 967        Event: 'static,
 968    {
 969        self.subscribe_internal(entity, move |entity, event, cx| {
 970            on_event(entity, event, cx);
 971            true
 972        })
 973    }
 974
 975    pub(crate) fn new_subscription(
 976        &mut self,
 977        key: EntityId,
 978        value: (TypeId, Listener),
 979    ) -> Subscription {
 980        let (subscription, activate) = self.event_listeners.insert(key, value);
 981        self.defer(move |_| activate());
 982        subscription
 983    }
 984    pub(crate) fn subscribe_internal<T, Evt>(
 985        &mut self,
 986        entity: &Entity<T>,
 987        mut on_event: impl FnMut(Entity<T>, &Evt, &mut App) -> bool + 'static,
 988    ) -> Subscription
 989    where
 990        T: 'static + EventEmitter<Evt>,
 991        Evt: 'static,
 992    {
 993        let entity_id = entity.entity_id();
 994        let handle = entity.downgrade();
 995        self.new_subscription(
 996            entity_id,
 997            (
 998                TypeId::of::<Evt>(),
 999                Box::new(move |event, cx| {
1000                    let event: &Evt = event.downcast_ref().expect("invalid event type");
1001                    if let Some(entity) = handle.upgrade() {
1002                        on_event(entity, event, cx)
1003                    } else {
1004                        false
1005                    }
1006                }),
1007            ),
1008        )
1009    }
1010
1011    /// Returns handles to all open windows in the application.
1012    /// Each handle could be downcast to a handle typed for the root view of that window.
1013    /// To find all windows of a given type, you could filter on
1014    pub fn windows(&self) -> Vec<AnyWindowHandle> {
1015        self.windows
1016            .keys()
1017            .flat_map(|window_id| self.window_handles.get(&window_id).copied())
1018            .collect()
1019    }
1020
1021    /// Returns the window handles ordered by their appearance on screen, front to back.
1022    ///
1023    /// The first window in the returned list is the active/topmost window of the application.
1024    ///
1025    /// This method returns None if the platform doesn't implement the method yet.
1026    pub fn window_stack(&self) -> Option<Vec<AnyWindowHandle>> {
1027        self.platform.window_stack()
1028    }
1029
1030    /// Returns a handle to the window that is currently focused at the platform level, if one exists.
1031    pub fn active_window(&self) -> Option<AnyWindowHandle> {
1032        self.platform.active_window()
1033    }
1034
1035    /// Opens a new window with the given option and the root view returned by the given function.
1036    /// The function is invoked with a `Window`, which can be used to interact with window-specific
1037    /// functionality.
1038    pub fn open_window<V: 'static + Render>(
1039        &mut self,
1040        options: crate::WindowOptions,
1041        build_root_view: impl FnOnce(&mut Window, &mut App) -> Entity<V>,
1042    ) -> anyhow::Result<WindowHandle<V>> {
1043        self.update(|cx| {
1044            let id = cx.windows.insert(None);
1045            let handle = WindowHandle::new(id);
1046            match Window::new(handle.into(), options, cx) {
1047                Ok(mut window) => {
1048                    cx.window_update_stack.push(id);
1049                    let root_view = build_root_view(&mut window, cx);
1050                    cx.window_update_stack.pop();
1051                    window.root.replace(root_view.into());
1052                    window.defer(cx, |window: &mut Window, cx| window.appearance_changed(cx));
1053
1054                    // allow a window to draw at least once before returning
1055                    // this didn't cause any issues on non windows platforms as it seems we always won the race to on_request_frame
1056                    // on windows we quite frequently lose the race and return a window that has never rendered, which leads to a crash
1057                    // where DispatchTree::root_node_id asserts on empty nodes
1058                    let clear = window.draw(cx);
1059                    clear.clear();
1060
1061                    cx.window_handles.insert(id, window.handle);
1062                    cx.windows.get_mut(id).unwrap().replace(Box::new(window));
1063                    Ok(handle)
1064                }
1065                Err(e) => {
1066                    cx.windows.remove(id);
1067                    Err(e)
1068                }
1069            }
1070        })
1071    }
1072
1073    /// Instructs the platform to activate the application by bringing it to the foreground.
1074    pub fn activate(&self, ignoring_other_apps: bool) {
1075        self.platform.activate(ignoring_other_apps);
1076    }
1077
1078    /// Hide the application at the platform level.
1079    pub fn hide(&self) {
1080        self.platform.hide();
1081    }
1082
1083    /// Hide other applications at the platform level.
1084    pub fn hide_other_apps(&self) {
1085        self.platform.hide_other_apps();
1086    }
1087
1088    /// Unhide other applications at the platform level.
1089    pub fn unhide_other_apps(&self) {
1090        self.platform.unhide_other_apps();
1091    }
1092
1093    /// Returns the list of currently active displays.
1094    pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
1095        self.platform.displays()
1096    }
1097
1098    /// Returns the primary display that will be used for new windows.
1099    pub fn primary_display(&self) -> Option<Rc<dyn PlatformDisplay>> {
1100        self.platform.primary_display()
1101    }
1102
1103    /// Returns whether `screen_capture_sources` may work.
1104    pub fn is_screen_capture_supported(&self) -> bool {
1105        self.platform.is_screen_capture_supported()
1106    }
1107
1108    /// Returns a list of available screen capture sources.
1109    pub fn screen_capture_sources(
1110        &self,
1111    ) -> oneshot::Receiver<Result<Vec<Rc<dyn ScreenCaptureSource>>>> {
1112        self.platform.screen_capture_sources()
1113    }
1114
1115    /// Returns the display with the given ID, if one exists.
1116    pub fn find_display(&self, id: DisplayId) -> Option<Rc<dyn PlatformDisplay>> {
1117        self.displays()
1118            .iter()
1119            .find(|display| display.id() == id)
1120            .cloned()
1121    }
1122
1123    /// Returns the current thermal state of the system.
1124    pub fn thermal_state(&self) -> ThermalState {
1125        self.platform.thermal_state()
1126    }
1127
1128    /// Invokes a handler when the thermal state changes
1129    pub fn on_thermal_state_change<F>(&self, mut callback: F) -> Subscription
1130    where
1131        F: 'static + FnMut(&mut App),
1132    {
1133        let (subscription, activate) = self.thermal_state_observers.insert(
1134            (),
1135            Box::new(move |cx| {
1136                callback(cx);
1137                true
1138            }),
1139        );
1140        activate();
1141        subscription
1142    }
1143
1144    /// Returns the appearance of the application's windows.
1145    pub fn window_appearance(&self) -> WindowAppearance {
1146        self.platform.window_appearance()
1147    }
1148
1149    /// Reads data from the platform clipboard.
1150    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
1151        self.platform.read_from_clipboard()
1152    }
1153
1154    /// Sets the text rendering mode for the application.
1155    pub fn set_text_rendering_mode(&mut self, mode: TextRenderingMode) {
1156        self.text_rendering_mode.set(mode);
1157    }
1158
1159    /// Returns the current text rendering mode for the application.
1160    pub fn text_rendering_mode(&self) -> TextRenderingMode {
1161        self.text_rendering_mode.get()
1162    }
1163
1164    /// Writes data to the platform clipboard.
1165    pub fn write_to_clipboard(&self, item: ClipboardItem) {
1166        self.platform.write_to_clipboard(item)
1167    }
1168
1169    /// Reads data from the primary selection buffer.
1170    /// Only available on Linux.
1171    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
1172    pub fn read_from_primary(&self) -> Option<ClipboardItem> {
1173        self.platform.read_from_primary()
1174    }
1175
1176    /// Writes data to the primary selection buffer.
1177    /// Only available on Linux.
1178    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
1179    pub fn write_to_primary(&self, item: ClipboardItem) {
1180        self.platform.write_to_primary(item)
1181    }
1182
1183    /// Reads data from macOS's "Find" pasteboard.
1184    ///
1185    /// Used to share the current search string between apps.
1186    ///
1187    /// https://developer.apple.com/documentation/appkit/nspasteboard/name-swift.struct/find
1188    #[cfg(target_os = "macos")]
1189    pub fn read_from_find_pasteboard(&self) -> Option<ClipboardItem> {
1190        self.platform.read_from_find_pasteboard()
1191    }
1192
1193    /// Writes data to macOS's "Find" pasteboard.
1194    ///
1195    /// Used to share the current search string between apps.
1196    ///
1197    /// https://developer.apple.com/documentation/appkit/nspasteboard/name-swift.struct/find
1198    #[cfg(target_os = "macos")]
1199    pub fn write_to_find_pasteboard(&self, item: ClipboardItem) {
1200        self.platform.write_to_find_pasteboard(item)
1201    }
1202
1203    /// Writes credentials to the platform keychain.
1204    pub fn write_credentials(
1205        &self,
1206        url: &str,
1207        username: &str,
1208        password: &[u8],
1209    ) -> Task<Result<()>> {
1210        self.platform.write_credentials(url, username, password)
1211    }
1212
1213    /// Reads credentials from the platform keychain.
1214    pub fn read_credentials(&self, url: &str) -> Task<Result<Option<(String, Vec<u8>)>>> {
1215        self.platform.read_credentials(url)
1216    }
1217
1218    /// Deletes credentials from the platform keychain.
1219    pub fn delete_credentials(&self, url: &str) -> Task<Result<()>> {
1220        self.platform.delete_credentials(url)
1221    }
1222
1223    /// Directs the platform's default browser to open the given URL.
1224    pub fn open_url(&self, url: &str) {
1225        self.platform.open_url(url);
1226    }
1227
1228    /// Registers the given URL scheme (e.g. `zed` for `zed://` urls) to be
1229    /// opened by the current app.
1230    ///
1231    /// On some platforms (e.g. macOS) you may be able to register URL schemes
1232    /// as part of app distribution, but this method exists to let you register
1233    /// schemes at runtime.
1234    pub fn register_url_scheme(&self, scheme: &str) -> Task<Result<()>> {
1235        self.platform.register_url_scheme(scheme)
1236    }
1237
1238    /// Returns the full pathname of the current app bundle.
1239    ///
1240    /// Returns an error if the app is not being run from a bundle.
1241    pub fn app_path(&self) -> Result<PathBuf> {
1242        self.platform.app_path()
1243    }
1244
1245    /// On Linux, returns the name of the compositor in use.
1246    ///
1247    /// Returns an empty string on other platforms.
1248    pub fn compositor_name(&self) -> &'static str {
1249        self.platform.compositor_name()
1250    }
1251
1252    /// Returns the file URL of the executable with the specified name in the application bundle
1253    pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
1254        self.platform.path_for_auxiliary_executable(name)
1255    }
1256
1257    /// Displays a platform modal for selecting paths.
1258    ///
1259    /// When one or more paths are selected, they'll be relayed asynchronously via the returned oneshot channel.
1260    /// If cancelled, a `None` will be relayed instead.
1261    /// May return an error on Linux if the file picker couldn't be opened.
1262    pub fn prompt_for_paths(
1263        &self,
1264        options: PathPromptOptions,
1265    ) -> oneshot::Receiver<Result<Option<Vec<PathBuf>>>> {
1266        self.platform.prompt_for_paths(options)
1267    }
1268
1269    /// Displays a platform modal for selecting a new path where a file can be saved.
1270    ///
1271    /// The provided directory will be used to set the initial location.
1272    /// When a path is selected, it is relayed asynchronously via the returned oneshot channel.
1273    /// If cancelled, a `None` will be relayed instead.
1274    /// May return an error on Linux if the file picker couldn't be opened.
1275    pub fn prompt_for_new_path(
1276        &self,
1277        directory: &Path,
1278        suggested_name: Option<&str>,
1279    ) -> oneshot::Receiver<Result<Option<PathBuf>>> {
1280        self.platform.prompt_for_new_path(directory, suggested_name)
1281    }
1282
1283    /// Reveals the specified path at the platform level, such as in Finder on macOS.
1284    pub fn reveal_path(&self, path: &Path) {
1285        self.platform.reveal_path(path)
1286    }
1287
1288    /// Opens the specified path with the system's default application.
1289    pub fn open_with_system(&self, path: &Path) {
1290        self.platform.open_with_system(path)
1291    }
1292
1293    /// Returns whether the user has configured scrollbars to auto-hide at the platform level.
1294    pub fn should_auto_hide_scrollbars(&self) -> bool {
1295        self.platform.should_auto_hide_scrollbars()
1296    }
1297
1298    /// Restarts the application.
1299    pub fn restart(&mut self) {
1300        self.restart_observers
1301            .clone()
1302            .retain(&(), |observer| observer(self));
1303        self.platform.restart(self.restart_path.take())
1304    }
1305
1306    /// Sets the path to use when restarting the application.
1307    pub fn set_restart_path(&mut self, path: PathBuf) {
1308        self.restart_path = Some(path);
1309    }
1310
1311    /// Returns the HTTP client for the application.
1312    pub fn http_client(&self) -> Arc<dyn HttpClient> {
1313        self.http_client.clone()
1314    }
1315
1316    /// Sets the HTTP client for the application.
1317    pub fn set_http_client(&mut self, new_client: Arc<dyn HttpClient>) {
1318        self.http_client = new_client;
1319    }
1320
1321    /// Configures when the application should automatically quit.
1322    /// By default, [`QuitMode::Default`] is used.
1323    pub fn set_quit_mode(&mut self, mode: QuitMode) {
1324        self.quit_mode = mode;
1325    }
1326
1327    /// Returns the SVG renderer used by the application.
1328    pub fn svg_renderer(&self) -> SvgRenderer {
1329        self.svg_renderer.clone()
1330    }
1331
1332    pub(crate) fn push_effect(&mut self, effect: Effect) {
1333        match &effect {
1334            Effect::Notify { emitter } => {
1335                if !self.pending_notifications.insert(*emitter) {
1336                    return;
1337                }
1338            }
1339            Effect::NotifyGlobalObservers { global_type } => {
1340                if !self.pending_global_notifications.insert(*global_type) {
1341                    return;
1342                }
1343            }
1344            _ => {}
1345        };
1346
1347        self.pending_effects.push_back(effect);
1348    }
1349
1350    /// Called at the end of [`App::update`] to complete any side effects
1351    /// such as notifying observers, emitting events, etc. Effects can themselves
1352    /// cause effects, so we continue looping until all effects are processed.
1353    fn flush_effects(&mut self) {
1354        loop {
1355            self.release_dropped_entities();
1356            self.release_dropped_focus_handles();
1357            if let Some(effect) = self.pending_effects.pop_front() {
1358                match effect {
1359                    Effect::Notify { emitter } => {
1360                        self.apply_notify_effect(emitter);
1361                    }
1362
1363                    Effect::Emit {
1364                        emitter,
1365                        event_type,
1366                        event,
1367                    } => self.apply_emit_effect(emitter, event_type, &*event),
1368
1369                    Effect::RefreshWindows => {
1370                        self.apply_refresh_effect();
1371                    }
1372
1373                    Effect::NotifyGlobalObservers { global_type } => {
1374                        self.apply_notify_global_observers_effect(global_type);
1375                    }
1376
1377                    Effect::Defer { callback } => {
1378                        self.apply_defer_effect(callback);
1379                    }
1380                    Effect::EntityCreated {
1381                        entity,
1382                        tid,
1383                        window,
1384                    } => {
1385                        self.apply_entity_created_effect(entity, tid, window);
1386                    }
1387                }
1388            } else {
1389                #[cfg(any(test, feature = "test-support"))]
1390                for window in self
1391                    .windows
1392                    .values()
1393                    .filter_map(|window| {
1394                        let window = window.as_deref()?;
1395                        window.invalidator.is_dirty().then_some(window.handle)
1396                    })
1397                    .collect::<Vec<_>>()
1398                {
1399                    self.update_window(window, |_, window, cx| window.draw(cx).clear())
1400                        .unwrap();
1401                }
1402
1403                if self.pending_effects.is_empty() {
1404                    self.event_arena.clear();
1405                    break;
1406                }
1407            }
1408        }
1409    }
1410
1411    /// Repeatedly called during `flush_effects` to release any entities whose
1412    /// reference count has become zero. We invoke any release observers before dropping
1413    /// each entity.
1414    fn release_dropped_entities(&mut self) {
1415        loop {
1416            let dropped = self.entities.take_dropped();
1417            if dropped.is_empty() {
1418                break;
1419            }
1420
1421            for (entity_id, mut entity) in dropped {
1422                self.observers.remove(&entity_id);
1423                self.event_listeners.remove(&entity_id);
1424                for release_callback in self.release_listeners.remove(&entity_id) {
1425                    release_callback(entity.as_mut(), self);
1426                }
1427            }
1428        }
1429    }
1430
1431    /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
1432    fn release_dropped_focus_handles(&mut self) {
1433        self.focus_handles
1434            .clone()
1435            .write()
1436            .retain(|handle_id, focus| {
1437                if focus.ref_count.load(SeqCst) == 0 {
1438                    for window_handle in self.windows() {
1439                        window_handle
1440                            .update(self, |_, window, _| {
1441                                if window.focus == Some(handle_id) {
1442                                    window.blur();
1443                                }
1444                            })
1445                            .unwrap();
1446                    }
1447                    false
1448                } else {
1449                    true
1450                }
1451            });
1452    }
1453
1454    fn apply_notify_effect(&mut self, emitter: EntityId) {
1455        self.pending_notifications.remove(&emitter);
1456
1457        self.observers
1458            .clone()
1459            .retain(&emitter, |handler| handler(self));
1460    }
1461
1462    fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: &dyn Any) {
1463        self.event_listeners
1464            .clone()
1465            .retain(&emitter, |(stored_type, handler)| {
1466                if *stored_type == event_type {
1467                    handler(event, self)
1468                } else {
1469                    true
1470                }
1471            });
1472    }
1473
1474    fn apply_refresh_effect(&mut self) {
1475        for window in self.windows.values_mut() {
1476            if let Some(window) = window.as_deref_mut() {
1477                window.refreshing = true;
1478                window.invalidator.set_dirty(true);
1479            }
1480        }
1481    }
1482
1483    fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
1484        self.pending_global_notifications.remove(&type_id);
1485        self.global_observers
1486            .clone()
1487            .retain(&type_id, |observer| observer(self));
1488    }
1489
1490    fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
1491        callback(self);
1492    }
1493
1494    fn apply_entity_created_effect(
1495        &mut self,
1496        entity: AnyEntity,
1497        tid: TypeId,
1498        window: Option<WindowId>,
1499    ) {
1500        self.new_entity_observers.clone().retain(&tid, |observer| {
1501            if let Some(id) = window {
1502                self.update_window_id(id, {
1503                    let entity = entity.clone();
1504                    |_, window, cx| (observer)(entity, &mut Some(window), cx)
1505                })
1506                .expect("All windows should be off the stack when flushing effects");
1507            } else {
1508                (observer)(entity.clone(), &mut None, self)
1509            }
1510            true
1511        });
1512    }
1513
1514    fn update_window_id<T, F>(&mut self, id: WindowId, update: F) -> Result<T>
1515    where
1516        F: FnOnce(AnyView, &mut Window, &mut App) -> T,
1517    {
1518        self.update(|cx| {
1519            let mut window = cx.windows.get_mut(id)?.take()?;
1520
1521            let root_view = window.root.clone().unwrap();
1522
1523            cx.window_update_stack.push(window.handle.id);
1524            let result = update(root_view, &mut window, cx);
1525            fn trail(id: WindowId, window: Box<Window>, cx: &mut App) -> Option<()> {
1526                cx.window_update_stack.pop();
1527
1528                if window.removed {
1529                    cx.window_handles.remove(&id);
1530                    cx.windows.remove(id);
1531
1532                    cx.window_closed_observers.clone().retain(&(), |callback| {
1533                        callback(cx);
1534                        true
1535                    });
1536
1537                    let quit_on_empty = match cx.quit_mode {
1538                        QuitMode::Explicit => false,
1539                        QuitMode::LastWindowClosed => true,
1540                        QuitMode::Default => cfg!(not(target_os = "macos")),
1541                    };
1542
1543                    if quit_on_empty && cx.windows.is_empty() {
1544                        cx.quit();
1545                    }
1546                } else {
1547                    cx.windows.get_mut(id)?.replace(window);
1548                }
1549                Some(())
1550            }
1551            trail(id, window, cx)?;
1552
1553            Some(result)
1554        })
1555        .context("window not found")
1556    }
1557
1558    /// Creates an `AsyncApp`, which can be cloned and has a static lifetime
1559    /// so it can be held across `await` points.
1560    pub fn to_async(&self) -> AsyncApp {
1561        AsyncApp {
1562            app: self.this.clone(),
1563            background_executor: self.background_executor.clone(),
1564            foreground_executor: self.foreground_executor.clone(),
1565        }
1566    }
1567
1568    /// Obtains a reference to the executor, which can be used to spawn futures.
1569    pub fn background_executor(&self) -> &BackgroundExecutor {
1570        &self.background_executor
1571    }
1572
1573    /// Obtains a reference to the executor, which can be used to spawn futures.
1574    pub fn foreground_executor(&self) -> &ForegroundExecutor {
1575        if self.quitting {
1576            panic!("Can't spawn on main thread after on_app_quit")
1577        };
1578        &self.foreground_executor
1579    }
1580
1581    /// Spawns the future returned by the given function on the main thread. The closure will be invoked
1582    /// with [AsyncApp], which allows the application state to be accessed across await points.
1583    #[track_caller]
1584    pub fn spawn<AsyncFn, R>(&self, f: AsyncFn) -> Task<R>
1585    where
1586        AsyncFn: AsyncFnOnce(&mut AsyncApp) -> R + 'static,
1587        R: 'static,
1588    {
1589        if self.quitting {
1590            debug_panic!("Can't spawn on main thread after on_app_quit")
1591        };
1592
1593        let mut cx = self.to_async();
1594
1595        self.foreground_executor
1596            .spawn(async move { f(&mut cx).await }.boxed_local())
1597    }
1598
1599    /// Spawns the future returned by the given function on the main thread with
1600    /// the given priority. The closure will be invoked with [AsyncApp], which
1601    /// allows the application state to be accessed across await points.
1602    pub fn spawn_with_priority<AsyncFn, R>(&self, priority: Priority, f: AsyncFn) -> Task<R>
1603    where
1604        AsyncFn: AsyncFnOnce(&mut AsyncApp) -> R + 'static,
1605        R: 'static,
1606    {
1607        if self.quitting {
1608            debug_panic!("Can't spawn on main thread after on_app_quit")
1609        };
1610
1611        let mut cx = self.to_async();
1612
1613        self.foreground_executor
1614            .spawn_with_priority(priority, async move { f(&mut cx).await }.boxed_local())
1615    }
1616
1617    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1618    /// that are currently on the stack to be returned to the app.
1619    pub fn defer(&mut self, f: impl FnOnce(&mut App) + 'static) {
1620        self.push_effect(Effect::Defer {
1621            callback: Box::new(f),
1622        });
1623    }
1624
1625    /// Accessor for the application's asset source, which is provided when constructing the `App`.
1626    pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
1627        &self.asset_source
1628    }
1629
1630    /// Accessor for the text system.
1631    pub fn text_system(&self) -> &Arc<TextSystem> {
1632        &self.text_system
1633    }
1634
1635    /// Check whether a global of the given type has been assigned.
1636    pub fn has_global<G: Global>(&self) -> bool {
1637        self.globals_by_type.contains_key(&TypeId::of::<G>())
1638    }
1639
1640    /// Access the global of the given type. Panics if a global for that type has not been assigned.
1641    #[track_caller]
1642    pub fn global<G: Global>(&self) -> &G {
1643        self.globals_by_type
1644            .get(&TypeId::of::<G>())
1645            .map(|any_state| any_state.downcast_ref::<G>().unwrap())
1646            .with_context(|| format!("no state of type {} exists", type_name::<G>()))
1647            .unwrap()
1648    }
1649
1650    /// Access the global of the given type if a value has been assigned.
1651    pub fn try_global<G: Global>(&self) -> Option<&G> {
1652        self.globals_by_type
1653            .get(&TypeId::of::<G>())
1654            .map(|any_state| any_state.downcast_ref::<G>().unwrap())
1655    }
1656
1657    /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
1658    #[track_caller]
1659    pub fn global_mut<G: Global>(&mut self) -> &mut G {
1660        let global_type = TypeId::of::<G>();
1661        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1662        self.globals_by_type
1663            .get_mut(&global_type)
1664            .and_then(|any_state| any_state.downcast_mut::<G>())
1665            .with_context(|| format!("no state of type {} exists", type_name::<G>()))
1666            .unwrap()
1667    }
1668
1669    /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
1670    /// yet been assigned.
1671    pub fn default_global<G: Global + Default>(&mut self) -> &mut G {
1672        let global_type = TypeId::of::<G>();
1673        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1674        self.globals_by_type
1675            .entry(global_type)
1676            .or_insert_with(|| Box::<G>::default())
1677            .downcast_mut::<G>()
1678            .unwrap()
1679    }
1680
1681    /// Sets the value of the global of the given type.
1682    pub fn set_global<G: Global>(&mut self, global: G) {
1683        let global_type = TypeId::of::<G>();
1684        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1685        self.globals_by_type.insert(global_type, Box::new(global));
1686    }
1687
1688    /// Clear all stored globals. Does not notify global observers.
1689    #[cfg(any(test, feature = "test-support"))]
1690    pub fn clear_globals(&mut self) {
1691        self.globals_by_type.drain();
1692    }
1693
1694    /// Remove the global of the given type from the app context. Does not notify global observers.
1695    pub fn remove_global<G: Global>(&mut self) -> G {
1696        let global_type = TypeId::of::<G>();
1697        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1698        *self
1699            .globals_by_type
1700            .remove(&global_type)
1701            .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
1702            .downcast()
1703            .unwrap()
1704    }
1705
1706    /// Register a callback to be invoked when a global of the given type is updated.
1707    pub fn observe_global<G: Global>(
1708        &mut self,
1709        mut f: impl FnMut(&mut Self) + 'static,
1710    ) -> Subscription {
1711        let (subscription, activate) = self.global_observers.insert(
1712            TypeId::of::<G>(),
1713            Box::new(move |cx| {
1714                f(cx);
1715                true
1716            }),
1717        );
1718        self.defer(move |_| activate());
1719        subscription
1720    }
1721
1722    /// Move the global of the given type to the stack.
1723    #[track_caller]
1724    pub(crate) fn lease_global<G: Global>(&mut self) -> GlobalLease<G> {
1725        GlobalLease::new(
1726            self.globals_by_type
1727                .remove(&TypeId::of::<G>())
1728                .with_context(|| format!("no global registered of type {}", type_name::<G>()))
1729                .unwrap(),
1730        )
1731    }
1732
1733    /// Restore the global of the given type after it is moved to the stack.
1734    pub(crate) fn end_global_lease<G: Global>(&mut self, lease: GlobalLease<G>) {
1735        let global_type = TypeId::of::<G>();
1736
1737        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1738        self.globals_by_type.insert(global_type, lease.global);
1739    }
1740
1741    pub(crate) fn new_entity_observer(
1742        &self,
1743        key: TypeId,
1744        value: NewEntityListener,
1745    ) -> Subscription {
1746        let (subscription, activate) = self.new_entity_observers.insert(key, value);
1747        activate();
1748        subscription
1749    }
1750
1751    /// Arrange for the given function to be invoked whenever a view of the specified type is created.
1752    /// The function will be passed a mutable reference to the view along with an appropriate context.
1753    pub fn observe_new<T: 'static>(
1754        &self,
1755        on_new: impl 'static + Fn(&mut T, Option<&mut Window>, &mut Context<T>),
1756    ) -> Subscription {
1757        self.new_entity_observer(
1758            TypeId::of::<T>(),
1759            Box::new(
1760                move |any_entity: AnyEntity, window: &mut Option<&mut Window>, cx: &mut App| {
1761                    any_entity
1762                        .downcast::<T>()
1763                        .unwrap()
1764                        .update(cx, |entity_state, cx| {
1765                            on_new(entity_state, window.as_deref_mut(), cx)
1766                        })
1767                },
1768            ),
1769        )
1770    }
1771
1772    /// Observe the release of a entity. The callback is invoked after the entity
1773    /// has no more strong references but before it has been dropped.
1774    pub fn observe_release<T>(
1775        &self,
1776        handle: &Entity<T>,
1777        on_release: impl FnOnce(&mut T, &mut App) + 'static,
1778    ) -> Subscription
1779    where
1780        T: 'static,
1781    {
1782        let (subscription, activate) = self.release_listeners.insert(
1783            handle.entity_id(),
1784            Box::new(move |entity, cx| {
1785                let entity = entity.downcast_mut().expect("invalid entity type");
1786                on_release(entity, cx)
1787            }),
1788        );
1789        activate();
1790        subscription
1791    }
1792
1793    /// Observe the release of a entity. The callback is invoked after the entity
1794    /// has no more strong references but before it has been dropped.
1795    pub fn observe_release_in<T>(
1796        &self,
1797        handle: &Entity<T>,
1798        window: &Window,
1799        on_release: impl FnOnce(&mut T, &mut Window, &mut App) + 'static,
1800    ) -> Subscription
1801    where
1802        T: 'static,
1803    {
1804        let window_handle = window.handle;
1805        self.observe_release(handle, move |entity, cx| {
1806            let _ = window_handle.update(cx, |_, window, cx| on_release(entity, window, cx));
1807        })
1808    }
1809
1810    /// Register a callback to be invoked when a keystroke is received by the application
1811    /// in any window. Note that this fires after all other action and event mechanisms have resolved
1812    /// and that this API will not be invoked if the event's propagation is stopped.
1813    pub fn observe_keystrokes(
1814        &mut self,
1815        mut f: impl FnMut(&KeystrokeEvent, &mut Window, &mut App) + 'static,
1816    ) -> Subscription {
1817        fn inner(
1818            keystroke_observers: &SubscriberSet<(), KeystrokeObserver>,
1819            handler: KeystrokeObserver,
1820        ) -> Subscription {
1821            let (subscription, activate) = keystroke_observers.insert((), handler);
1822            activate();
1823            subscription
1824        }
1825
1826        inner(
1827            &self.keystroke_observers,
1828            Box::new(move |event, window, cx| {
1829                f(event, window, cx);
1830                true
1831            }),
1832        )
1833    }
1834
1835    /// Register a callback to be invoked when a keystroke is received by the application
1836    /// in any window. Note that this fires _before_ all other action and event mechanisms have resolved
1837    /// unlike [`App::observe_keystrokes`] which fires after. This means that `cx.stop_propagation` calls
1838    /// within interceptors will prevent action dispatch
1839    pub fn intercept_keystrokes(
1840        &mut self,
1841        mut f: impl FnMut(&KeystrokeEvent, &mut Window, &mut App) + 'static,
1842    ) -> Subscription {
1843        fn inner(
1844            keystroke_interceptors: &SubscriberSet<(), KeystrokeObserver>,
1845            handler: KeystrokeObserver,
1846        ) -> Subscription {
1847            let (subscription, activate) = keystroke_interceptors.insert((), handler);
1848            activate();
1849            subscription
1850        }
1851
1852        inner(
1853            &self.keystroke_interceptors,
1854            Box::new(move |event, window, cx| {
1855                f(event, window, cx);
1856                true
1857            }),
1858        )
1859    }
1860
1861    /// Register key bindings.
1862    pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
1863        self.keymap.borrow_mut().add_bindings(bindings);
1864        self.pending_effects.push_back(Effect::RefreshWindows);
1865    }
1866
1867    /// Clear all key bindings in the app.
1868    pub fn clear_key_bindings(&mut self) {
1869        self.keymap.borrow_mut().clear();
1870        self.pending_effects.push_back(Effect::RefreshWindows);
1871    }
1872
1873    /// Get all key bindings in the app.
1874    pub fn key_bindings(&self) -> Rc<RefCell<Keymap>> {
1875        self.keymap.clone()
1876    }
1877
1878    /// Register a global handler for actions invoked via the keyboard. These handlers are run at
1879    /// the end of the bubble phase for actions, and so will only be invoked if there are no other
1880    /// handlers or if they called `cx.propagate()`.
1881    pub fn on_action<A: Action>(
1882        &mut self,
1883        listener: impl Fn(&A, &mut Self) + 'static,
1884    ) -> &mut Self {
1885        self.global_action_listeners
1886            .entry(TypeId::of::<A>())
1887            .or_default()
1888            .push(Rc::new(move |action, phase, cx| {
1889                if phase == DispatchPhase::Bubble {
1890                    let action = action.downcast_ref().unwrap();
1891                    listener(action, cx)
1892                }
1893            }));
1894        self
1895    }
1896
1897    /// Event handlers propagate events by default. Call this method to stop dispatching to
1898    /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
1899    /// the opposite of [`Self::propagate`]. It's also possible to cancel a call to [`Self::propagate`] by
1900    /// calling this method before effects are flushed.
1901    pub fn stop_propagation(&mut self) {
1902        self.propagate_event = false;
1903    }
1904
1905    /// Action handlers stop propagation by default during the bubble phase of action dispatch
1906    /// dispatching to action handlers higher in the element tree. This is the opposite of
1907    /// [`Self::stop_propagation`]. It's also possible to cancel a call to [`Self::stop_propagation`] by calling
1908    /// this method before effects are flushed.
1909    pub fn propagate(&mut self) {
1910        self.propagate_event = true;
1911    }
1912
1913    /// Build an action from some arbitrary data, typically a keymap entry.
1914    pub fn build_action(
1915        &self,
1916        name: &str,
1917        data: Option<serde_json::Value>,
1918    ) -> std::result::Result<Box<dyn Action>, ActionBuildError> {
1919        self.actions.build_action(name, data)
1920    }
1921
1922    /// Get all action names that have been registered. Note that registration only allows for
1923    /// actions to be built dynamically, and is unrelated to binding actions in the element tree.
1924    pub fn all_action_names(&self) -> &[&'static str] {
1925        self.actions.all_action_names()
1926    }
1927
1928    /// Returns key bindings that invoke the given action on the currently focused element, without
1929    /// checking context. Bindings are returned in the order they were added. For display, the last
1930    /// binding should take precedence.
1931    pub fn all_bindings_for_input(&self, input: &[Keystroke]) -> Vec<KeyBinding> {
1932        RefCell::borrow(&self.keymap).all_bindings_for_input(input)
1933    }
1934
1935    /// Get all non-internal actions that have been registered, along with their schemas.
1936    pub fn action_schemas(
1937        &self,
1938        generator: &mut schemars::SchemaGenerator,
1939    ) -> Vec<(&'static str, Option<schemars::Schema>)> {
1940        self.actions.action_schemas(generator)
1941    }
1942
1943    /// Get the schema for a specific action by name.
1944    /// Returns `None` if the action is not found.
1945    /// Returns `Some(None)` if the action exists but has no schema.
1946    /// Returns `Some(Some(schema))` if the action exists and has a schema.
1947    pub fn action_schema_by_name(
1948        &self,
1949        name: &str,
1950        generator: &mut schemars::SchemaGenerator,
1951    ) -> Option<Option<schemars::Schema>> {
1952        self.actions.action_schema_by_name(name, generator)
1953    }
1954
1955    /// Get a map from a deprecated action name to the canonical name.
1956    pub fn deprecated_actions_to_preferred_actions(&self) -> &HashMap<&'static str, &'static str> {
1957        self.actions.deprecated_aliases()
1958    }
1959
1960    /// Get a map from an action name to the deprecation messages.
1961    pub fn action_deprecation_messages(&self) -> &HashMap<&'static str, &'static str> {
1962        self.actions.deprecation_messages()
1963    }
1964
1965    /// Get a map from an action name to the documentation.
1966    pub fn action_documentation(&self) -> &HashMap<&'static str, &'static str> {
1967        self.actions.documentation()
1968    }
1969
1970    /// Register a callback to be invoked when the application is about to quit.
1971    /// It is not possible to cancel the quit event at this point.
1972    pub fn on_app_quit<Fut>(
1973        &self,
1974        mut on_quit: impl FnMut(&mut App) -> Fut + 'static,
1975    ) -> Subscription
1976    where
1977        Fut: 'static + Future<Output = ()>,
1978    {
1979        let (subscription, activate) = self.quit_observers.insert(
1980            (),
1981            Box::new(move |cx| {
1982                let future = on_quit(cx);
1983                future.boxed_local()
1984            }),
1985        );
1986        activate();
1987        subscription
1988    }
1989
1990    /// Register a callback to be invoked when the application is about to restart.
1991    ///
1992    /// These callbacks are called before any `on_app_quit` callbacks.
1993    pub fn on_app_restart(&self, mut on_restart: impl 'static + FnMut(&mut App)) -> Subscription {
1994        let (subscription, activate) = self.restart_observers.insert(
1995            (),
1996            Box::new(move |cx| {
1997                on_restart(cx);
1998                true
1999            }),
2000        );
2001        activate();
2002        subscription
2003    }
2004
2005    /// Register a callback to be invoked when a window is closed
2006    /// The window is no longer accessible at the point this callback is invoked.
2007    pub fn on_window_closed(&self, mut on_closed: impl FnMut(&mut App) + 'static) -> Subscription {
2008        let (subscription, activate) = self.window_closed_observers.insert((), Box::new(on_closed));
2009        activate();
2010        subscription
2011    }
2012
2013    pub(crate) fn clear_pending_keystrokes(&mut self) {
2014        for window in self.windows() {
2015            window
2016                .update(self, |_, window, cx| {
2017                    if window.pending_input_keystrokes().is_some() {
2018                        window.clear_pending_keystrokes();
2019                        window.pending_input_changed(cx);
2020                    }
2021                })
2022                .ok();
2023        }
2024    }
2025
2026    /// Checks if the given action is bound in the current context, as defined by the app's current focus,
2027    /// the bindings in the element tree, and any global action listeners.
2028    pub fn is_action_available(&mut self, action: &dyn Action) -> bool {
2029        let mut action_available = false;
2030        if let Some(window) = self.active_window()
2031            && let Ok(window_action_available) =
2032                window.update(self, |_, window, cx| window.is_action_available(action, cx))
2033        {
2034            action_available = window_action_available;
2035        }
2036
2037        action_available
2038            || self
2039                .global_action_listeners
2040                .contains_key(&action.as_any().type_id())
2041    }
2042
2043    /// Sets the menu bar for this application. This will replace any existing menu bar.
2044    pub fn set_menus(&self, menus: Vec<Menu>) {
2045        self.platform.set_menus(menus, &self.keymap.borrow());
2046    }
2047
2048    /// Gets the menu bar for this application.
2049    pub fn get_menus(&self) -> Option<Vec<OwnedMenu>> {
2050        self.platform.get_menus()
2051    }
2052
2053    /// Sets the right click menu for the app icon in the dock
2054    pub fn set_dock_menu(&self, menus: Vec<MenuItem>) {
2055        self.platform.set_dock_menu(menus, &self.keymap.borrow())
2056    }
2057
2058    /// Performs the action associated with the given dock menu item, only used on Windows for now.
2059    pub fn perform_dock_menu_action(&self, action: usize) {
2060        self.platform.perform_dock_menu_action(action);
2061    }
2062
2063    /// Adds given path to the bottom of the list of recent paths for the application.
2064    /// The list is usually shown on the application icon's context menu in the dock,
2065    /// and allows to open the recent files via that context menu.
2066    /// If the path is already in the list, it will be moved to the bottom of the list.
2067    pub fn add_recent_document(&self, path: &Path) {
2068        self.platform.add_recent_document(path);
2069    }
2070
2071    /// Updates the jump list with the updated list of recent paths for the application, only used on Windows for now.
2072    /// Note that this also sets the dock menu on Windows.
2073    pub fn update_jump_list(
2074        &self,
2075        menus: Vec<MenuItem>,
2076        entries: Vec<SmallVec<[PathBuf; 2]>>,
2077    ) -> Task<Vec<SmallVec<[PathBuf; 2]>>> {
2078        self.platform.update_jump_list(menus, entries)
2079    }
2080
2081    /// Dispatch an action to the currently active window or global action handler
2082    /// See [`crate::Action`] for more information on how actions work
2083    pub fn dispatch_action(&mut self, action: &dyn Action) {
2084        if let Some(active_window) = self.active_window() {
2085            active_window
2086                .update(self, |_, window, cx| {
2087                    window.dispatch_action(action.boxed_clone(), cx)
2088                })
2089                .log_err();
2090        } else {
2091            self.dispatch_global_action(action);
2092        }
2093    }
2094
2095    fn dispatch_global_action(&mut self, action: &dyn Action) {
2096        self.propagate_event = true;
2097
2098        if let Some(mut global_listeners) = self
2099            .global_action_listeners
2100            .remove(&action.as_any().type_id())
2101        {
2102            for listener in &global_listeners {
2103                listener(action.as_any(), DispatchPhase::Capture, self);
2104                if !self.propagate_event {
2105                    break;
2106                }
2107            }
2108
2109            global_listeners.extend(
2110                self.global_action_listeners
2111                    .remove(&action.as_any().type_id())
2112                    .unwrap_or_default(),
2113            );
2114
2115            self.global_action_listeners
2116                .insert(action.as_any().type_id(), global_listeners);
2117        }
2118
2119        if self.propagate_event
2120            && let Some(mut global_listeners) = self
2121                .global_action_listeners
2122                .remove(&action.as_any().type_id())
2123        {
2124            for listener in global_listeners.iter().rev() {
2125                listener(action.as_any(), DispatchPhase::Bubble, self);
2126                if !self.propagate_event {
2127                    break;
2128                }
2129            }
2130
2131            global_listeners.extend(
2132                self.global_action_listeners
2133                    .remove(&action.as_any().type_id())
2134                    .unwrap_or_default(),
2135            );
2136
2137            self.global_action_listeners
2138                .insert(action.as_any().type_id(), global_listeners);
2139        }
2140    }
2141
2142    /// Is there currently something being dragged?
2143    pub fn has_active_drag(&self) -> bool {
2144        self.active_drag.is_some()
2145    }
2146
2147    /// Gets the cursor style of the currently active drag operation.
2148    pub fn active_drag_cursor_style(&self) -> Option<CursorStyle> {
2149        self.active_drag.as_ref().and_then(|drag| drag.cursor_style)
2150    }
2151
2152    /// Stops active drag and clears any related effects.
2153    pub fn stop_active_drag(&mut self, window: &mut Window) -> bool {
2154        if self.active_drag.is_some() {
2155            self.active_drag = None;
2156            window.refresh();
2157            true
2158        } else {
2159            false
2160        }
2161    }
2162
2163    /// Sets the cursor style for the currently active drag operation.
2164    pub fn set_active_drag_cursor_style(
2165        &mut self,
2166        cursor_style: CursorStyle,
2167        window: &mut Window,
2168    ) -> bool {
2169        if let Some(ref mut drag) = self.active_drag {
2170            drag.cursor_style = Some(cursor_style);
2171            window.refresh();
2172            true
2173        } else {
2174            false
2175        }
2176    }
2177
2178    /// Set the prompt renderer for GPUI. This will replace the default or platform specific
2179    /// prompts with this custom implementation.
2180    pub fn set_prompt_builder(
2181        &mut self,
2182        renderer: impl Fn(
2183            PromptLevel,
2184            &str,
2185            Option<&str>,
2186            &[PromptButton],
2187            PromptHandle,
2188            &mut Window,
2189            &mut App,
2190        ) -> RenderablePromptHandle
2191        + 'static,
2192    ) {
2193        self.prompt_builder = Some(PromptBuilder::Custom(Box::new(renderer)));
2194    }
2195
2196    /// Reset the prompt builder to the default implementation.
2197    pub fn reset_prompt_builder(&mut self) {
2198        self.prompt_builder = Some(PromptBuilder::Default);
2199    }
2200
2201    /// Remove an asset from GPUI's cache
2202    pub fn remove_asset<A: Asset>(&mut self, source: &A::Source) {
2203        let asset_id = (TypeId::of::<A>(), hash(source));
2204        self.loading_assets.remove(&asset_id);
2205    }
2206
2207    /// Asynchronously load an asset, if the asset hasn't finished loading this will return None.
2208    ///
2209    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
2210    /// time, and the results of this call will be cached
2211    pub fn fetch_asset<A: Asset>(&mut self, source: &A::Source) -> (Shared<Task<A::Output>>, bool) {
2212        let asset_id = (TypeId::of::<A>(), hash(source));
2213        let mut is_first = false;
2214        let task = self
2215            .loading_assets
2216            .remove(&asset_id)
2217            .map(|boxed_task| *boxed_task.downcast::<Shared<Task<A::Output>>>().unwrap())
2218            .unwrap_or_else(|| {
2219                is_first = true;
2220                let future = A::load(source.clone(), self);
2221
2222                self.background_executor().spawn(future).shared()
2223            });
2224
2225        self.loading_assets.insert(asset_id, Box::new(task.clone()));
2226
2227        (task, is_first)
2228    }
2229
2230    /// Obtain a new [`FocusHandle`], which allows you to track and manipulate the keyboard focus
2231    /// for elements rendered within this window.
2232    #[track_caller]
2233    pub fn focus_handle(&self) -> FocusHandle {
2234        FocusHandle::new(&self.focus_handles)
2235    }
2236
2237    /// Tell GPUI that an entity has changed and observers of it should be notified.
2238    pub fn notify(&mut self, entity_id: EntityId) {
2239        let window_invalidators = mem::take(
2240            self.window_invalidators_by_entity
2241                .entry(entity_id)
2242                .or_default(),
2243        );
2244
2245        if window_invalidators.is_empty() {
2246            if self.pending_notifications.insert(entity_id) {
2247                self.pending_effects
2248                    .push_back(Effect::Notify { emitter: entity_id });
2249            }
2250        } else {
2251            for invalidator in window_invalidators.values() {
2252                invalidator.invalidate_view(entity_id, self);
2253            }
2254        }
2255
2256        self.window_invalidators_by_entity
2257            .insert(entity_id, window_invalidators);
2258    }
2259
2260    /// Returns the name for this [`App`].
2261    #[cfg(any(test, feature = "test-support", debug_assertions))]
2262    pub fn get_name(&self) -> Option<&'static str> {
2263        self.name
2264    }
2265
2266    /// Returns `true` if the platform file picker supports selecting a mix of files and directories.
2267    pub fn can_select_mixed_files_and_dirs(&self) -> bool {
2268        self.platform.can_select_mixed_files_and_dirs()
2269    }
2270
2271    /// Removes an image from the sprite atlas on all windows.
2272    ///
2273    /// If the current window is being updated, it will be removed from `App.windows`, you can use `current_window` to specify the current window.
2274    /// This is a no-op if the image is not in the sprite atlas.
2275    pub fn drop_image(&mut self, image: Arc<RenderImage>, current_window: Option<&mut Window>) {
2276        // remove the texture from all other windows
2277        for window in self.windows.values_mut().flatten() {
2278            _ = window.drop_image(image.clone());
2279        }
2280
2281        // remove the texture from the current window
2282        if let Some(window) = current_window {
2283            _ = window.drop_image(image);
2284        }
2285    }
2286
2287    /// Sets the renderer for the inspector.
2288    #[cfg(any(feature = "inspector", debug_assertions))]
2289    pub fn set_inspector_renderer(&mut self, f: crate::InspectorRenderer) {
2290        self.inspector_renderer = Some(f);
2291    }
2292
2293    /// Registers a renderer specific to an inspector state.
2294    #[cfg(any(feature = "inspector", debug_assertions))]
2295    pub fn register_inspector_element<T: 'static, R: crate::IntoElement>(
2296        &mut self,
2297        f: impl 'static + Fn(crate::InspectorElementId, &T, &mut Window, &mut App) -> R,
2298    ) {
2299        self.inspector_element_registry.register(f);
2300    }
2301
2302    /// Initializes gpui's default colors for the application.
2303    ///
2304    /// These colors can be accessed through `cx.default_colors()`.
2305    pub fn init_colors(&mut self) {
2306        self.set_global(GlobalColors(Arc::new(Colors::default())));
2307    }
2308}
2309
2310impl AppContext for App {
2311    /// Builds an entity that is owned by the application.
2312    ///
2313    /// The given function will be invoked with a [`Context`] and must return an object representing the entity. An
2314    /// [`Entity`] handle will be returned, which can be used to access the entity in a context.
2315    fn new<T: 'static>(&mut self, build_entity: impl FnOnce(&mut Context<T>) -> T) -> Entity<T> {
2316        self.update(|cx| {
2317            let slot = cx.entities.reserve();
2318            let handle = slot.clone();
2319            let entity = build_entity(&mut Context::new_context(cx, slot.downgrade()));
2320
2321            cx.push_effect(Effect::EntityCreated {
2322                entity: handle.clone().into_any(),
2323                tid: TypeId::of::<T>(),
2324                window: cx.window_update_stack.last().cloned(),
2325            });
2326
2327            cx.entities.insert(slot, entity);
2328            handle
2329        })
2330    }
2331
2332    fn reserve_entity<T: 'static>(&mut self) -> Reservation<T> {
2333        Reservation(self.entities.reserve())
2334    }
2335
2336    fn insert_entity<T: 'static>(
2337        &mut self,
2338        reservation: Reservation<T>,
2339        build_entity: impl FnOnce(&mut Context<T>) -> T,
2340    ) -> Entity<T> {
2341        self.update(|cx| {
2342            let slot = reservation.0;
2343            let entity = build_entity(&mut Context::new_context(cx, slot.downgrade()));
2344            cx.entities.insert(slot, entity)
2345        })
2346    }
2347
2348    /// Updates the entity referenced by the given handle. The function is passed a mutable reference to the
2349    /// entity along with a `Context` for the entity.
2350    fn update_entity<T: 'static, R>(
2351        &mut self,
2352        handle: &Entity<T>,
2353        update: impl FnOnce(&mut T, &mut Context<T>) -> R,
2354    ) -> R {
2355        self.update(|cx| {
2356            let mut entity = cx.entities.lease(handle);
2357            let result = update(
2358                &mut entity,
2359                &mut Context::new_context(cx, handle.downgrade()),
2360            );
2361            cx.entities.end_lease(entity);
2362            result
2363        })
2364    }
2365
2366    fn as_mut<'a, T>(&'a mut self, handle: &Entity<T>) -> GpuiBorrow<'a, T>
2367    where
2368        T: 'static,
2369    {
2370        GpuiBorrow::new(handle.clone(), self)
2371    }
2372
2373    fn read_entity<T, R>(&self, handle: &Entity<T>, read: impl FnOnce(&T, &App) -> R) -> R
2374    where
2375        T: 'static,
2376    {
2377        let entity = self.entities.read(handle);
2378        read(entity, self)
2379    }
2380
2381    fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
2382    where
2383        F: FnOnce(AnyView, &mut Window, &mut App) -> T,
2384    {
2385        self.update_window_id(handle.id, update)
2386    }
2387
2388    fn read_window<T, R>(
2389        &self,
2390        window: &WindowHandle<T>,
2391        read: impl FnOnce(Entity<T>, &App) -> R,
2392    ) -> Result<R>
2393    where
2394        T: 'static,
2395    {
2396        let window = self
2397            .windows
2398            .get(window.id)
2399            .context("window not found")?
2400            .as_deref()
2401            .expect("attempted to read a window that is already on the stack");
2402
2403        let root_view = window.root.clone().unwrap();
2404        let view = root_view
2405            .downcast::<T>()
2406            .map_err(|_| anyhow!("root view's type has changed"))?;
2407
2408        Ok(read(view, self))
2409    }
2410
2411    fn background_spawn<R>(&self, future: impl Future<Output = R> + Send + 'static) -> Task<R>
2412    where
2413        R: Send + 'static,
2414    {
2415        self.background_executor.spawn(future)
2416    }
2417
2418    fn read_global<G, R>(&self, callback: impl FnOnce(&G, &App) -> R) -> R
2419    where
2420        G: Global,
2421    {
2422        let mut g = self.global::<G>();
2423        callback(g, self)
2424    }
2425}
2426
2427/// These effects are processed at the end of each application update cycle.
2428pub(crate) enum Effect {
2429    Notify {
2430        emitter: EntityId,
2431    },
2432    Emit {
2433        emitter: EntityId,
2434        event_type: TypeId,
2435        event: ArenaBox<dyn Any>,
2436    },
2437    RefreshWindows,
2438    NotifyGlobalObservers {
2439        global_type: TypeId,
2440    },
2441    Defer {
2442        callback: Box<dyn FnOnce(&mut App) + 'static>,
2443    },
2444    EntityCreated {
2445        entity: AnyEntity,
2446        tid: TypeId,
2447        window: Option<WindowId>,
2448    },
2449}
2450
2451impl std::fmt::Debug for Effect {
2452    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
2453        match self {
2454            Effect::Notify { emitter } => write!(f, "Notify({})", emitter),
2455            Effect::Emit { emitter, .. } => write!(f, "Emit({:?})", emitter),
2456            Effect::RefreshWindows => write!(f, "RefreshWindows"),
2457            Effect::NotifyGlobalObservers { global_type } => {
2458                write!(f, "NotifyGlobalObservers({:?})", global_type)
2459            }
2460            Effect::Defer { .. } => write!(f, "Defer(..)"),
2461            Effect::EntityCreated { entity, .. } => write!(f, "EntityCreated({:?})", entity),
2462        }
2463    }
2464}
2465
2466/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
2467pub(crate) struct GlobalLease<G: Global> {
2468    global: Box<dyn Any>,
2469    global_type: PhantomData<G>,
2470}
2471
2472impl<G: Global> GlobalLease<G> {
2473    fn new(global: Box<dyn Any>) -> Self {
2474        GlobalLease {
2475            global,
2476            global_type: PhantomData,
2477        }
2478    }
2479}
2480
2481impl<G: Global> Deref for GlobalLease<G> {
2482    type Target = G;
2483
2484    fn deref(&self) -> &Self::Target {
2485        self.global.downcast_ref().unwrap()
2486    }
2487}
2488
2489impl<G: Global> DerefMut for GlobalLease<G> {
2490    fn deref_mut(&mut self) -> &mut Self::Target {
2491        self.global.downcast_mut().unwrap()
2492    }
2493}
2494
2495/// Contains state associated with an active drag operation, started by dragging an element
2496/// within the window or by dragging into the app from the underlying platform.
2497pub struct AnyDrag {
2498    /// The view used to render this drag
2499    pub view: AnyView,
2500
2501    /// The value of the dragged item, to be dropped
2502    pub value: Arc<dyn Any>,
2503
2504    /// This is used to render the dragged item in the same place
2505    /// on the original element that the drag was initiated
2506    pub cursor_offset: Point<Pixels>,
2507
2508    /// The cursor style to use while dragging
2509    pub cursor_style: Option<CursorStyle>,
2510}
2511
2512/// Contains state associated with a tooltip. You'll only need this struct if you're implementing
2513/// tooltip behavior on a custom element. Otherwise, use [Div::tooltip](crate::Interactivity::tooltip).
2514#[derive(Clone)]
2515pub struct AnyTooltip {
2516    /// The view used to display the tooltip
2517    pub view: AnyView,
2518
2519    /// The absolute position of the mouse when the tooltip was deployed.
2520    pub mouse_position: Point<Pixels>,
2521
2522    /// Given the bounds of the tooltip, checks whether the tooltip should still be visible and
2523    /// updates its state accordingly. This is needed atop the hovered element's mouse move handler
2524    /// to handle the case where the element is not painted (e.g. via use of `visible_on_hover`).
2525    pub check_visible_and_update: Rc<dyn Fn(Bounds<Pixels>, &mut Window, &mut App) -> bool>,
2526}
2527
2528/// A keystroke event, and potentially the associated action
2529#[derive(Debug)]
2530pub struct KeystrokeEvent {
2531    /// The keystroke that occurred
2532    pub keystroke: Keystroke,
2533
2534    /// The action that was resolved for the keystroke, if any
2535    pub action: Option<Box<dyn Action>>,
2536
2537    /// The context stack at the time
2538    pub context_stack: Vec<KeyContext>,
2539}
2540
2541struct NullHttpClient;
2542
2543impl HttpClient for NullHttpClient {
2544    fn send(
2545        &self,
2546        _req: http_client::Request<http_client::AsyncBody>,
2547    ) -> futures::future::BoxFuture<
2548        'static,
2549        anyhow::Result<http_client::Response<http_client::AsyncBody>>,
2550    > {
2551        async move {
2552            anyhow::bail!("No HttpClient available");
2553        }
2554        .boxed()
2555    }
2556
2557    fn user_agent(&self) -> Option<&http_client::http::HeaderValue> {
2558        None
2559    }
2560
2561    fn proxy(&self) -> Option<&Url> {
2562        None
2563    }
2564}
2565
2566/// A mutable reference to an entity owned by GPUI
2567pub struct GpuiBorrow<'a, T> {
2568    inner: Option<Lease<T>>,
2569    app: &'a mut App,
2570}
2571
2572impl<'a, T: 'static> GpuiBorrow<'a, T> {
2573    fn new(inner: Entity<T>, app: &'a mut App) -> Self {
2574        app.start_update();
2575        let lease = app.entities.lease(&inner);
2576        Self {
2577            inner: Some(lease),
2578            app,
2579        }
2580    }
2581}
2582
2583impl<'a, T: 'static> std::borrow::Borrow<T> for GpuiBorrow<'a, T> {
2584    fn borrow(&self) -> &T {
2585        self.inner.as_ref().unwrap().borrow()
2586    }
2587}
2588
2589impl<'a, T: 'static> std::borrow::BorrowMut<T> for GpuiBorrow<'a, T> {
2590    fn borrow_mut(&mut self) -> &mut T {
2591        self.inner.as_mut().unwrap().borrow_mut()
2592    }
2593}
2594
2595impl<'a, T: 'static> std::ops::Deref for GpuiBorrow<'a, T> {
2596    type Target = T;
2597
2598    fn deref(&self) -> &Self::Target {
2599        self.inner.as_ref().unwrap()
2600    }
2601}
2602
2603impl<'a, T: 'static> std::ops::DerefMut for GpuiBorrow<'a, T> {
2604    fn deref_mut(&mut self) -> &mut T {
2605        self.inner.as_mut().unwrap()
2606    }
2607}
2608
2609impl<'a, T> Drop for GpuiBorrow<'a, T> {
2610    fn drop(&mut self) {
2611        let lease = self.inner.take().unwrap();
2612        self.app.notify(lease.id);
2613        self.app.entities.end_lease(lease);
2614        self.app.finish_update();
2615    }
2616}
2617
2618#[cfg(test)]
2619mod test {
2620    use std::{cell::RefCell, rc::Rc};
2621
2622    use crate::{AppContext, TestAppContext};
2623
2624    #[test]
2625    fn test_gpui_borrow() {
2626        let cx = TestAppContext::single();
2627        let observation_count = Rc::new(RefCell::new(0));
2628
2629        let state = cx.update(|cx| {
2630            let state = cx.new(|_| false);
2631            cx.observe(&state, {
2632                let observation_count = observation_count.clone();
2633                move |_, _| {
2634                    let mut count = observation_count.borrow_mut();
2635                    *count += 1;
2636                }
2637            })
2638            .detach();
2639
2640            state
2641        });
2642
2643        cx.update(|cx| {
2644            // Calling this like this so that we don't clobber the borrow_mut above
2645            *std::borrow::BorrowMut::borrow_mut(&mut state.as_mut(cx)) = true;
2646        });
2647
2648        cx.update(|cx| {
2649            state.write(cx, false);
2650        });
2651
2652        assert_eq!(*observation_count.borrow(), 2);
2653    }
2654}