app.rs

   1use std::{
   2    any::{type_name, TypeId},
   3    cell::{Ref, RefCell, RefMut},
   4    marker::PhantomData,
   5    mem,
   6    ops::{Deref, DerefMut},
   7    path::{Path, PathBuf},
   8    rc::{Rc, Weak},
   9    sync::{atomic::Ordering::SeqCst, Arc},
  10    time::Duration,
  11};
  12
  13use anyhow::{anyhow, Result};
  14use derive_more::{Deref, DerefMut};
  15use futures::{
  16    channel::oneshot,
  17    future::{LocalBoxFuture, Shared},
  18    Future, FutureExt,
  19};
  20use parking_lot::RwLock;
  21use slotmap::SlotMap;
  22
  23pub use async_context::*;
  24use collections::{FxHashMap, FxHashSet, HashMap, VecDeque};
  25pub use context::*;
  26pub use entity_map::*;
  27use http_client::HttpClient;
  28#[cfg(any(test, feature = "test-support"))]
  29pub use test_context::*;
  30use util::ResultExt;
  31
  32use crate::{
  33    current_platform, hash, init_app_menus, Action, ActionBuildError, ActionRegistry, Any, AnyView,
  34    AnyWindowHandle, AppContext, Asset, AssetSource, BackgroundExecutor, Bounds, ClipboardItem,
  35    DispatchPhase, DisplayId, EventEmitter, FocusHandle, FocusMap, ForegroundExecutor, Global,
  36    KeyBinding, Keymap, Keystroke, LayoutId, Menu, MenuItem, OwnedMenu, PathPromptOptions, Pixels,
  37    Platform, PlatformDisplay, Point, PromptBuilder, PromptHandle, PromptLevel, Render,
  38    RenderablePromptHandle, Reservation, ScreenCaptureSource, SharedString, SubscriberSet,
  39    Subscription, SvgRenderer, Task, TextSystem, Window, WindowAppearance, WindowHandle, WindowId,
  40    WindowInvalidator,
  41};
  42
  43mod async_context;
  44mod context;
  45mod entity_map;
  46#[cfg(any(test, feature = "test-support"))]
  47mod test_context;
  48
  49/// The duration for which futures returned from [Context::on_app_quit] can run before the application fully quits.
  50pub const SHUTDOWN_TIMEOUT: Duration = Duration::from_millis(100);
  51
  52/// Temporary(?) wrapper around [`RefCell<App>`] to help us debug any double borrows.
  53/// Strongly consider removing after stabilization.
  54#[doc(hidden)]
  55pub struct AppCell {
  56    app: RefCell<App>,
  57}
  58
  59impl AppCell {
  60    #[doc(hidden)]
  61    #[track_caller]
  62    pub fn borrow(&self) -> AppRef {
  63        if option_env!("TRACK_THREAD_BORROWS").is_some() {
  64            let thread_id = std::thread::current().id();
  65            eprintln!("borrowed {thread_id:?}");
  66        }
  67        AppRef(self.app.borrow())
  68    }
  69
  70    #[doc(hidden)]
  71    #[track_caller]
  72    pub fn borrow_mut(&self) -> AppRefMut {
  73        if option_env!("TRACK_THREAD_BORROWS").is_some() {
  74            let thread_id = std::thread::current().id();
  75            eprintln!("borrowed {thread_id:?}");
  76        }
  77        AppRefMut(self.app.borrow_mut())
  78    }
  79}
  80
  81#[doc(hidden)]
  82#[derive(Deref, DerefMut)]
  83pub struct AppRef<'a>(Ref<'a, App>);
  84
  85impl Drop for AppRef<'_> {
  86    fn drop(&mut self) {
  87        if option_env!("TRACK_THREAD_BORROWS").is_some() {
  88            let thread_id = std::thread::current().id();
  89            eprintln!("dropped borrow from {thread_id:?}");
  90        }
  91    }
  92}
  93
  94#[doc(hidden)]
  95#[derive(Deref, DerefMut)]
  96pub struct AppRefMut<'a>(RefMut<'a, App>);
  97
  98impl Drop for AppRefMut<'_> {
  99    fn drop(&mut self) {
 100        if option_env!("TRACK_THREAD_BORROWS").is_some() {
 101            let thread_id = std::thread::current().id();
 102            eprintln!("dropped {thread_id:?}");
 103        }
 104    }
 105}
 106
 107/// A reference to a GPUI application, typically constructed in the `main` function of your app.
 108/// You won't interact with this type much outside of initial configuration and startup.
 109pub struct Application(Rc<AppCell>);
 110
 111/// Represents an application before it is fully launched. Once your app is
 112/// configured, you'll start the app with `App::run`.
 113impl Application {
 114    /// Builds an app with the given asset source.
 115    #[allow(clippy::new_without_default)]
 116    pub fn new() -> Self {
 117        #[cfg(any(test, feature = "test-support"))]
 118        log::info!("GPUI was compiled in test mode");
 119
 120        Self(App::new_app(
 121            current_platform(false),
 122            Arc::new(()),
 123            Arc::new(NullHttpClient),
 124        ))
 125    }
 126
 127    /// Build an app in headless mode. This prevents opening windows,
 128    /// but makes it possible to run an application in an context like
 129    /// SSH, where GUI applications are not allowed.
 130    pub fn headless() -> Self {
 131        Self(App::new_app(
 132            current_platform(true),
 133            Arc::new(()),
 134            Arc::new(NullHttpClient),
 135        ))
 136    }
 137
 138    /// Assign
 139    pub fn with_assets(self, asset_source: impl AssetSource) -> Self {
 140        let mut context_lock = self.0.borrow_mut();
 141        let asset_source = Arc::new(asset_source);
 142        context_lock.asset_source = asset_source.clone();
 143        context_lock.svg_renderer = SvgRenderer::new(asset_source);
 144        drop(context_lock);
 145        self
 146    }
 147
 148    /// Sets the HTTP client for the application.
 149    pub fn with_http_client(self, http_client: Arc<dyn HttpClient>) -> Self {
 150        let mut context_lock = self.0.borrow_mut();
 151        context_lock.http_client = http_client;
 152        drop(context_lock);
 153        self
 154    }
 155
 156    /// Start the application. The provided callback will be called once the
 157    /// app is fully launched.
 158    pub fn run<F>(self, on_finish_launching: F)
 159    where
 160        F: 'static + FnOnce(&mut App),
 161    {
 162        let this = self.0.clone();
 163        let platform = self.0.borrow().platform.clone();
 164        platform.run(Box::new(move || {
 165            let cx = &mut *this.borrow_mut();
 166            on_finish_launching(cx);
 167        }));
 168    }
 169
 170    /// Register a handler to be invoked when the platform instructs the application
 171    /// to open one or more URLs.
 172    pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
 173    where
 174        F: 'static + FnMut(Vec<String>),
 175    {
 176        self.0.borrow().platform.on_open_urls(Box::new(callback));
 177        self
 178    }
 179
 180    /// Invokes a handler when an already-running application is launched.
 181    /// On macOS, this can occur when the application icon is double-clicked or the app is launched via the dock.
 182    pub fn on_reopen<F>(&self, mut callback: F) -> &Self
 183    where
 184        F: 'static + FnMut(&mut App),
 185    {
 186        let this = Rc::downgrade(&self.0);
 187        self.0.borrow_mut().platform.on_reopen(Box::new(move || {
 188            if let Some(app) = this.upgrade() {
 189                callback(&mut app.borrow_mut());
 190            }
 191        }));
 192        self
 193    }
 194
 195    /// Returns a handle to the [`BackgroundExecutor`] associated with this app, which can be used to spawn futures in the background.
 196    pub fn background_executor(&self) -> BackgroundExecutor {
 197        self.0.borrow().background_executor.clone()
 198    }
 199
 200    /// Returns a handle to the [`ForegroundExecutor`] associated with this app, which can be used to spawn futures in the foreground.
 201    pub fn foreground_executor(&self) -> ForegroundExecutor {
 202        self.0.borrow().foreground_executor.clone()
 203    }
 204
 205    /// Returns a reference to the [`TextSystem`] associated with this app.
 206    pub fn text_system(&self) -> Arc<TextSystem> {
 207        self.0.borrow().text_system.clone()
 208    }
 209
 210    /// Returns the file URL of the executable with the specified name in the application bundle
 211    pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
 212        self.0.borrow().path_for_auxiliary_executable(name)
 213    }
 214}
 215
 216type Handler = Box<dyn FnMut(&mut App) -> bool + 'static>;
 217type Listener = Box<dyn FnMut(&dyn Any, &mut App) -> bool + 'static>;
 218pub(crate) type KeystrokeObserver =
 219    Box<dyn FnMut(&KeystrokeEvent, &mut Window, &mut App) -> bool + 'static>;
 220type QuitHandler = Box<dyn FnOnce(&mut App) -> LocalBoxFuture<'static, ()> + 'static>;
 221type WindowClosedHandler = Box<dyn FnMut(&mut App)>;
 222type ReleaseListener = Box<dyn FnOnce(&mut dyn Any, &mut App) + 'static>;
 223type NewEntityListener = Box<dyn FnMut(AnyEntity, &mut Option<&mut Window>, &mut App) + 'static>;
 224
 225/// Contains the state of the full application, and passed as a reference to a variety of callbacks.
 226/// Other [Context] derefs to this type.
 227/// You need a reference to an `App` to access the state of a [Entity].
 228pub struct App {
 229    pub(crate) this: Weak<AppCell>,
 230    pub(crate) platform: Rc<dyn Platform>,
 231    text_system: Arc<TextSystem>,
 232    flushing_effects: bool,
 233    pending_updates: usize,
 234    pub(crate) actions: Rc<ActionRegistry>,
 235    pub(crate) active_drag: Option<AnyDrag>,
 236    pub(crate) background_executor: BackgroundExecutor,
 237    pub(crate) foreground_executor: ForegroundExecutor,
 238    pub(crate) loading_assets: FxHashMap<(TypeId, u64), Box<dyn Any>>,
 239    asset_source: Arc<dyn AssetSource>,
 240    pub(crate) svg_renderer: SvgRenderer,
 241    http_client: Arc<dyn HttpClient>,
 242    pub(crate) globals_by_type: FxHashMap<TypeId, Box<dyn Any>>,
 243    pub(crate) entities: EntityMap,
 244    pub(crate) window_update_stack: Vec<WindowId>,
 245    pub(crate) new_entity_observers: SubscriberSet<TypeId, NewEntityListener>,
 246    pub(crate) windows: SlotMap<WindowId, Option<Window>>,
 247    pub(crate) window_handles: FxHashMap<WindowId, AnyWindowHandle>,
 248    pub(crate) focus_handles: Arc<FocusMap>,
 249    pub(crate) keymap: Rc<RefCell<Keymap>>,
 250    pub(crate) keyboard_layout: SharedString,
 251    pub(crate) global_action_listeners:
 252        FxHashMap<TypeId, Vec<Rc<dyn Fn(&dyn Any, DispatchPhase, &mut Self)>>>,
 253    pending_effects: VecDeque<Effect>,
 254    pub(crate) pending_notifications: FxHashSet<EntityId>,
 255    pub(crate) pending_global_notifications: FxHashSet<TypeId>,
 256    pub(crate) observers: SubscriberSet<EntityId, Handler>,
 257    // TypeId is the type of the event that the listener callback expects
 258    pub(crate) event_listeners: SubscriberSet<EntityId, (TypeId, Listener)>,
 259    pub(crate) keystroke_observers: SubscriberSet<(), KeystrokeObserver>,
 260    pub(crate) keyboard_layout_observers: SubscriberSet<(), Handler>,
 261    pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
 262    pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
 263    pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
 264    pub(crate) window_closed_observers: SubscriberSet<(), WindowClosedHandler>,
 265    pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
 266    pub(crate) propagate_event: bool,
 267    pub(crate) prompt_builder: Option<PromptBuilder>,
 268    pub(crate) window_invalidators_by_entity:
 269        FxHashMap<EntityId, FxHashMap<WindowId, WindowInvalidator>>,
 270    pub(crate) tracked_entities: FxHashMap<WindowId, FxHashSet<EntityId>>,
 271    #[cfg(any(test, feature = "test-support", debug_assertions))]
 272    pub(crate) name: Option<&'static str>,
 273}
 274
 275impl App {
 276    #[allow(clippy::new_ret_no_self)]
 277    pub(crate) fn new_app(
 278        platform: Rc<dyn Platform>,
 279        asset_source: Arc<dyn AssetSource>,
 280        http_client: Arc<dyn HttpClient>,
 281    ) -> Rc<AppCell> {
 282        let executor = platform.background_executor();
 283        let foreground_executor = platform.foreground_executor();
 284        assert!(
 285            executor.is_main_thread(),
 286            "must construct App on main thread"
 287        );
 288
 289        let text_system = Arc::new(TextSystem::new(platform.text_system()));
 290        let entities = EntityMap::new();
 291        let keyboard_layout = SharedString::from(platform.keyboard_layout());
 292
 293        let app = Rc::new_cyclic(|this| AppCell {
 294            app: RefCell::new(App {
 295                this: this.clone(),
 296                platform: platform.clone(),
 297                text_system,
 298                actions: Rc::new(ActionRegistry::default()),
 299                flushing_effects: false,
 300                pending_updates: 0,
 301                active_drag: None,
 302                background_executor: executor,
 303                foreground_executor,
 304                svg_renderer: SvgRenderer::new(asset_source.clone()),
 305                loading_assets: Default::default(),
 306                asset_source,
 307                http_client,
 308                globals_by_type: FxHashMap::default(),
 309                entities,
 310                new_entity_observers: SubscriberSet::new(),
 311                windows: SlotMap::with_key(),
 312                window_update_stack: Vec::new(),
 313                window_handles: FxHashMap::default(),
 314                focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
 315                keymap: Rc::new(RefCell::new(Keymap::default())),
 316                keyboard_layout,
 317                global_action_listeners: FxHashMap::default(),
 318                pending_effects: VecDeque::new(),
 319                pending_notifications: FxHashSet::default(),
 320                pending_global_notifications: FxHashSet::default(),
 321                observers: SubscriberSet::new(),
 322                tracked_entities: FxHashMap::default(),
 323                window_invalidators_by_entity: FxHashMap::default(),
 324                event_listeners: SubscriberSet::new(),
 325                release_listeners: SubscriberSet::new(),
 326                keystroke_observers: SubscriberSet::new(),
 327                keyboard_layout_observers: SubscriberSet::new(),
 328                global_observers: SubscriberSet::new(),
 329                quit_observers: SubscriberSet::new(),
 330                window_closed_observers: SubscriberSet::new(),
 331                layout_id_buffer: Default::default(),
 332                propagate_event: true,
 333                prompt_builder: Some(PromptBuilder::Default),
 334
 335                #[cfg(any(test, feature = "test-support", debug_assertions))]
 336                name: None,
 337            }),
 338        });
 339
 340        init_app_menus(platform.as_ref(), &mut app.borrow_mut());
 341
 342        platform.on_keyboard_layout_change(Box::new({
 343            let app = Rc::downgrade(&app);
 344            move || {
 345                if let Some(app) = app.upgrade() {
 346                    let cx = &mut app.borrow_mut();
 347                    cx.keyboard_layout = SharedString::from(cx.platform.keyboard_layout());
 348                    cx.keyboard_layout_observers
 349                        .clone()
 350                        .retain(&(), move |callback| (callback)(cx));
 351                }
 352            }
 353        }));
 354
 355        platform.on_quit(Box::new({
 356            let cx = app.clone();
 357            move || {
 358                cx.borrow_mut().shutdown();
 359            }
 360        }));
 361
 362        app
 363    }
 364
 365    /// Quit the application gracefully. Handlers registered with [`Context::on_app_quit`]
 366    /// will be given 100ms to complete before exiting.
 367    pub fn shutdown(&mut self) {
 368        let mut futures = Vec::new();
 369
 370        for observer in self.quit_observers.remove(&()) {
 371            futures.push(observer(self));
 372        }
 373
 374        self.windows.clear();
 375        self.window_handles.clear();
 376        self.flush_effects();
 377
 378        let futures = futures::future::join_all(futures);
 379        if self
 380            .background_executor
 381            .block_with_timeout(SHUTDOWN_TIMEOUT, futures)
 382            .is_err()
 383        {
 384            log::error!("timed out waiting on app_will_quit");
 385        }
 386    }
 387
 388    /// Get the id of the current keyboard layout
 389    pub fn keyboard_layout(&self) -> &SharedString {
 390        &self.keyboard_layout
 391    }
 392
 393    /// Invokes a handler when the current keyboard layout changes
 394    pub fn on_keyboard_layout_change<F>(&self, mut callback: F) -> Subscription
 395    where
 396        F: 'static + FnMut(&mut App),
 397    {
 398        let (subscription, activate) = self.keyboard_layout_observers.insert(
 399            (),
 400            Box::new(move |cx| {
 401                callback(cx);
 402                true
 403            }),
 404        );
 405        activate();
 406        subscription
 407    }
 408
 409    /// Gracefully quit the application via the platform's standard routine.
 410    pub fn quit(&self) {
 411        self.platform.quit();
 412    }
 413
 414    /// Schedules all windows in the application to be redrawn. This can be called
 415    /// multiple times in an update cycle and still result in a single redraw.
 416    pub fn refresh_windows(&mut self) {
 417        self.pending_effects.push_back(Effect::RefreshWindows);
 418    }
 419
 420    pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
 421        self.pending_updates += 1;
 422        let result = update(self);
 423        if !self.flushing_effects && self.pending_updates == 1 {
 424            self.flushing_effects = true;
 425            self.flush_effects();
 426            self.flushing_effects = false;
 427        }
 428        self.pending_updates -= 1;
 429        result
 430    }
 431
 432    /// Arrange a callback to be invoked when the given entity calls `notify` on its respective context.
 433    pub fn observe<W>(
 434        &mut self,
 435        entity: &Entity<W>,
 436        mut on_notify: impl FnMut(Entity<W>, &mut App) + 'static,
 437    ) -> Subscription
 438    where
 439        W: 'static,
 440    {
 441        self.observe_internal(entity, move |e, cx| {
 442            on_notify(e, cx);
 443            true
 444        })
 445    }
 446
 447    pub(crate) fn detect_accessed_entities<R>(
 448        &mut self,
 449        callback: impl FnOnce(&mut App) -> R,
 450    ) -> (R, FxHashSet<EntityId>) {
 451        let accessed_entities_start = self.entities.accessed_entities.borrow().clone();
 452        let result = callback(self);
 453        let accessed_entities_end = self.entities.accessed_entities.borrow().clone();
 454        let entities_accessed_in_callback = accessed_entities_end
 455            .difference(&accessed_entities_start)
 456            .copied()
 457            .collect::<FxHashSet<EntityId>>();
 458        (result, entities_accessed_in_callback)
 459    }
 460
 461    pub(crate) fn record_entities_accessed(
 462        &mut self,
 463        window_handle: AnyWindowHandle,
 464        invalidator: WindowInvalidator,
 465        entities: &FxHashSet<EntityId>,
 466    ) {
 467        let mut tracked_entities =
 468            std::mem::take(self.tracked_entities.entry(window_handle.id).or_default());
 469        for entity in tracked_entities.iter() {
 470            self.window_invalidators_by_entity
 471                .entry(*entity)
 472                .and_modify(|windows| {
 473                    windows.remove(&window_handle.id);
 474                });
 475        }
 476        for entity in entities.iter() {
 477            self.window_invalidators_by_entity
 478                .entry(*entity)
 479                .or_default()
 480                .insert(window_handle.id, invalidator.clone());
 481        }
 482        tracked_entities.clear();
 483        tracked_entities.extend(entities.iter().copied());
 484        self.tracked_entities
 485            .insert(window_handle.id, tracked_entities);
 486    }
 487
 488    pub(crate) fn new_observer(&mut self, key: EntityId, value: Handler) -> Subscription {
 489        let (subscription, activate) = self.observers.insert(key, value);
 490        self.defer(move |_| activate());
 491        subscription
 492    }
 493
 494    pub(crate) fn observe_internal<W>(
 495        &mut self,
 496        entity: &Entity<W>,
 497        mut on_notify: impl FnMut(Entity<W>, &mut App) -> bool + 'static,
 498    ) -> Subscription
 499    where
 500        W: 'static,
 501    {
 502        let entity_id = entity.entity_id();
 503        let handle = entity.downgrade();
 504        self.new_observer(
 505            entity_id,
 506            Box::new(move |cx| {
 507                if let Some(handle) = Entity::<W>::upgrade_from(&handle) {
 508                    on_notify(handle, cx)
 509                } else {
 510                    false
 511                }
 512            }),
 513        )
 514    }
 515
 516    /// Arrange for the given callback to be invoked whenever the given entity emits an event of a given type.
 517    /// The callback is provided a handle to the emitting entity and a reference to the emitted event.
 518    pub fn subscribe<T, Event>(
 519        &mut self,
 520        entity: &Entity<T>,
 521        mut on_event: impl FnMut(Entity<T>, &Event, &mut App) + 'static,
 522    ) -> Subscription
 523    where
 524        T: 'static + EventEmitter<Event>,
 525        Event: 'static,
 526    {
 527        self.subscribe_internal(entity, move |entity, event, cx| {
 528            on_event(entity, event, cx);
 529            true
 530        })
 531    }
 532
 533    pub(crate) fn new_subscription(
 534        &mut self,
 535        key: EntityId,
 536        value: (TypeId, Listener),
 537    ) -> Subscription {
 538        let (subscription, activate) = self.event_listeners.insert(key, value);
 539        self.defer(move |_| activate());
 540        subscription
 541    }
 542    pub(crate) fn subscribe_internal<T, Evt>(
 543        &mut self,
 544        entity: &Entity<T>,
 545        mut on_event: impl FnMut(Entity<T>, &Evt, &mut App) -> bool + 'static,
 546    ) -> Subscription
 547    where
 548        T: 'static + EventEmitter<Evt>,
 549        Evt: 'static,
 550    {
 551        let entity_id = entity.entity_id();
 552        let entity = entity.downgrade();
 553        self.new_subscription(
 554            entity_id,
 555            (
 556                TypeId::of::<Evt>(),
 557                Box::new(move |event, cx| {
 558                    let event: &Evt = event.downcast_ref().expect("invalid event type");
 559                    if let Some(handle) = Entity::<T>::upgrade_from(&entity) {
 560                        on_event(handle, event, cx)
 561                    } else {
 562                        false
 563                    }
 564                }),
 565            ),
 566        )
 567    }
 568
 569    /// Returns handles to all open windows in the application.
 570    /// Each handle could be downcast to a handle typed for the root view of that window.
 571    /// To find all windows of a given type, you could filter on
 572    pub fn windows(&self) -> Vec<AnyWindowHandle> {
 573        self.windows
 574            .keys()
 575            .flat_map(|window_id| self.window_handles.get(&window_id).copied())
 576            .collect()
 577    }
 578
 579    /// Returns the window handles ordered by their appearance on screen, front to back.
 580    ///
 581    /// The first window in the returned list is the active/topmost window of the application.
 582    ///
 583    /// This method returns None if the platform doesn't implement the method yet.
 584    pub fn window_stack(&self) -> Option<Vec<AnyWindowHandle>> {
 585        self.platform.window_stack()
 586    }
 587
 588    /// Returns a handle to the window that is currently focused at the platform level, if one exists.
 589    pub fn active_window(&self) -> Option<AnyWindowHandle> {
 590        self.platform.active_window()
 591    }
 592
 593    /// Opens a new window with the given option and the root view returned by the given function.
 594    /// The function is invoked with a `Window`, which can be used to interact with window-specific
 595    /// functionality.
 596    pub fn open_window<V: 'static + Render>(
 597        &mut self,
 598        options: crate::WindowOptions,
 599        build_root_view: impl FnOnce(&mut Window, &mut App) -> Entity<V>,
 600    ) -> anyhow::Result<WindowHandle<V>> {
 601        self.update(|cx| {
 602            let id = cx.windows.insert(None);
 603            let handle = WindowHandle::new(id);
 604            match Window::new(handle.into(), options, cx) {
 605                Ok(mut window) => {
 606                    cx.window_update_stack.push(id);
 607                    let root_view = build_root_view(&mut window, cx);
 608                    cx.window_update_stack.pop();
 609                    window.root.replace(root_view.into());
 610                    window.defer(cx, |window: &mut Window, cx| window.appearance_changed(cx));
 611                    cx.window_handles.insert(id, window.handle);
 612                    cx.windows.get_mut(id).unwrap().replace(window);
 613                    Ok(handle)
 614                }
 615                Err(e) => {
 616                    cx.windows.remove(id);
 617                    Err(e)
 618                }
 619            }
 620        })
 621    }
 622
 623    /// Instructs the platform to activate the application by bringing it to the foreground.
 624    pub fn activate(&self, ignoring_other_apps: bool) {
 625        self.platform.activate(ignoring_other_apps);
 626    }
 627
 628    /// Hide the application at the platform level.
 629    pub fn hide(&self) {
 630        self.platform.hide();
 631    }
 632
 633    /// Hide other applications at the platform level.
 634    pub fn hide_other_apps(&self) {
 635        self.platform.hide_other_apps();
 636    }
 637
 638    /// Unhide other applications at the platform level.
 639    pub fn unhide_other_apps(&self) {
 640        self.platform.unhide_other_apps();
 641    }
 642
 643    /// Returns the list of currently active displays.
 644    pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
 645        self.platform.displays()
 646    }
 647
 648    /// Returns the primary display that will be used for new windows.
 649    pub fn primary_display(&self) -> Option<Rc<dyn PlatformDisplay>> {
 650        self.platform.primary_display()
 651    }
 652
 653    /// Returns a list of available screen capture sources.
 654    pub fn screen_capture_sources(
 655        &self,
 656    ) -> oneshot::Receiver<Result<Vec<Box<dyn ScreenCaptureSource>>>> {
 657        self.platform.screen_capture_sources()
 658    }
 659
 660    /// Returns the display with the given ID, if one exists.
 661    pub fn find_display(&self, id: DisplayId) -> Option<Rc<dyn PlatformDisplay>> {
 662        self.displays()
 663            .iter()
 664            .find(|display| display.id() == id)
 665            .cloned()
 666    }
 667
 668    /// Returns the appearance of the application's windows.
 669    pub fn window_appearance(&self) -> WindowAppearance {
 670        self.platform.window_appearance()
 671    }
 672
 673    /// Writes data to the primary selection buffer.
 674    /// Only available on Linux.
 675    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
 676    pub fn write_to_primary(&self, item: ClipboardItem) {
 677        self.platform.write_to_primary(item)
 678    }
 679
 680    /// Writes data to the platform clipboard.
 681    pub fn write_to_clipboard(&self, item: ClipboardItem) {
 682        self.platform.write_to_clipboard(item)
 683    }
 684
 685    /// Reads data from the primary selection buffer.
 686    /// Only available on Linux.
 687    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
 688    pub fn read_from_primary(&self) -> Option<ClipboardItem> {
 689        self.platform.read_from_primary()
 690    }
 691
 692    /// Reads data from the platform clipboard.
 693    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
 694        self.platform.read_from_clipboard()
 695    }
 696
 697    /// Writes credentials to the platform keychain.
 698    pub fn write_credentials(
 699        &self,
 700        url: &str,
 701        username: &str,
 702        password: &[u8],
 703    ) -> Task<Result<()>> {
 704        self.platform.write_credentials(url, username, password)
 705    }
 706
 707    /// Reads credentials from the platform keychain.
 708    pub fn read_credentials(&self, url: &str) -> Task<Result<Option<(String, Vec<u8>)>>> {
 709        self.platform.read_credentials(url)
 710    }
 711
 712    /// Deletes credentials from the platform keychain.
 713    pub fn delete_credentials(&self, url: &str) -> Task<Result<()>> {
 714        self.platform.delete_credentials(url)
 715    }
 716
 717    /// Directs the platform's default browser to open the given URL.
 718    pub fn open_url(&self, url: &str) {
 719        self.platform.open_url(url);
 720    }
 721
 722    /// Registers the given URL scheme (e.g. `zed` for `zed://` urls) to be
 723    /// opened by the current app.
 724    ///
 725    /// On some platforms (e.g. macOS) you may be able to register URL schemes
 726    /// as part of app distribution, but this method exists to let you register
 727    /// schemes at runtime.
 728    pub fn register_url_scheme(&self, scheme: &str) -> Task<Result<()>> {
 729        self.platform.register_url_scheme(scheme)
 730    }
 731
 732    /// Returns the full pathname of the current app bundle.
 733    ///
 734    /// Returns an error if the app is not being run from a bundle.
 735    pub fn app_path(&self) -> Result<PathBuf> {
 736        self.platform.app_path()
 737    }
 738
 739    /// On Linux, returns the name of the compositor in use.
 740    ///
 741    /// Returns an empty string on other platforms.
 742    pub fn compositor_name(&self) -> &'static str {
 743        self.platform.compositor_name()
 744    }
 745
 746    /// Returns the file URL of the executable with the specified name in the application bundle
 747    pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
 748        self.platform.path_for_auxiliary_executable(name)
 749    }
 750
 751    /// Displays a platform modal for selecting paths.
 752    ///
 753    /// When one or more paths are selected, they'll be relayed asynchronously via the returned oneshot channel.
 754    /// If cancelled, a `None` will be relayed instead.
 755    /// May return an error on Linux if the file picker couldn't be opened.
 756    pub fn prompt_for_paths(
 757        &self,
 758        options: PathPromptOptions,
 759    ) -> oneshot::Receiver<Result<Option<Vec<PathBuf>>>> {
 760        self.platform.prompt_for_paths(options)
 761    }
 762
 763    /// Displays a platform modal for selecting a new path where a file can be saved.
 764    ///
 765    /// The provided directory will be used to set the initial location.
 766    /// When a path is selected, it is relayed asynchronously via the returned oneshot channel.
 767    /// If cancelled, a `None` will be relayed instead.
 768    /// May return an error on Linux if the file picker couldn't be opened.
 769    pub fn prompt_for_new_path(
 770        &self,
 771        directory: &Path,
 772    ) -> oneshot::Receiver<Result<Option<PathBuf>>> {
 773        self.platform.prompt_for_new_path(directory)
 774    }
 775
 776    /// Reveals the specified path at the platform level, such as in Finder on macOS.
 777    pub fn reveal_path(&self, path: &Path) {
 778        self.platform.reveal_path(path)
 779    }
 780
 781    /// Opens the specified path with the system's default application.
 782    pub fn open_with_system(&self, path: &Path) {
 783        self.platform.open_with_system(path)
 784    }
 785
 786    /// Returns whether the user has configured scrollbars to auto-hide at the platform level.
 787    pub fn should_auto_hide_scrollbars(&self) -> bool {
 788        self.platform.should_auto_hide_scrollbars()
 789    }
 790
 791    /// Restarts the application.
 792    pub fn restart(&self, binary_path: Option<PathBuf>) {
 793        self.platform.restart(binary_path)
 794    }
 795
 796    /// Returns the HTTP client for the application.
 797    pub fn http_client(&self) -> Arc<dyn HttpClient> {
 798        self.http_client.clone()
 799    }
 800
 801    /// Sets the HTTP client for the application.
 802    pub fn set_http_client(&mut self, new_client: Arc<dyn HttpClient>) {
 803        self.http_client = new_client;
 804    }
 805
 806    /// Returns the SVG renderer used by the application.
 807    pub fn svg_renderer(&self) -> SvgRenderer {
 808        self.svg_renderer.clone()
 809    }
 810
 811    pub(crate) fn push_effect(&mut self, effect: Effect) {
 812        match &effect {
 813            Effect::Notify { emitter } => {
 814                if !self.pending_notifications.insert(*emitter) {
 815                    return;
 816                }
 817            }
 818            Effect::NotifyGlobalObservers { global_type } => {
 819                if !self.pending_global_notifications.insert(*global_type) {
 820                    return;
 821                }
 822            }
 823            _ => {}
 824        };
 825
 826        self.pending_effects.push_back(effect);
 827    }
 828
 829    /// Called at the end of [`App::update`] to complete any side effects
 830    /// such as notifying observers, emitting events, etc. Effects can themselves
 831    /// cause effects, so we continue looping until all effects are processed.
 832    fn flush_effects(&mut self) {
 833        loop {
 834            self.release_dropped_entities();
 835            self.release_dropped_focus_handles();
 836
 837            if let Some(effect) = self.pending_effects.pop_front() {
 838                match effect {
 839                    Effect::Notify { emitter } => {
 840                        self.apply_notify_effect(emitter);
 841                    }
 842
 843                    Effect::Emit {
 844                        emitter,
 845                        event_type,
 846                        event,
 847                    } => self.apply_emit_effect(emitter, event_type, event),
 848
 849                    Effect::RefreshWindows => {
 850                        self.apply_refresh_effect();
 851                    }
 852
 853                    Effect::NotifyGlobalObservers { global_type } => {
 854                        self.apply_notify_global_observers_effect(global_type);
 855                    }
 856
 857                    Effect::Defer { callback } => {
 858                        self.apply_defer_effect(callback);
 859                    }
 860                    Effect::EntityCreated {
 861                        entity,
 862                        tid,
 863                        window,
 864                    } => {
 865                        self.apply_entity_created_effect(entity, tid, window);
 866                    }
 867                }
 868            } else {
 869                #[cfg(any(test, feature = "test-support"))]
 870                for window in self
 871                    .windows
 872                    .values()
 873                    .filter_map(|window| {
 874                        let window = window.as_ref()?;
 875                        window.invalidator.is_dirty().then_some(window.handle)
 876                    })
 877                    .collect::<Vec<_>>()
 878                {
 879                    self.update_window(window, |_, window, cx| window.draw(cx))
 880                        .unwrap();
 881                }
 882
 883                if self.pending_effects.is_empty() {
 884                    break;
 885                }
 886            }
 887        }
 888    }
 889
 890    /// Repeatedly called during `flush_effects` to release any entities whose
 891    /// reference count has become zero. We invoke any release observers before dropping
 892    /// each entity.
 893    fn release_dropped_entities(&mut self) {
 894        loop {
 895            let dropped = self.entities.take_dropped();
 896            if dropped.is_empty() {
 897                break;
 898            }
 899
 900            for (entity_id, mut entity) in dropped {
 901                self.observers.remove(&entity_id);
 902                self.event_listeners.remove(&entity_id);
 903                for release_callback in self.release_listeners.remove(&entity_id) {
 904                    release_callback(entity.as_mut(), self);
 905                }
 906            }
 907        }
 908    }
 909
 910    /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
 911    fn release_dropped_focus_handles(&mut self) {
 912        self.focus_handles
 913            .clone()
 914            .write()
 915            .retain(|handle_id, count| {
 916                if count.load(SeqCst) == 0 {
 917                    for window_handle in self.windows() {
 918                        window_handle
 919                            .update(self, |_, window, _| {
 920                                if window.focus == Some(handle_id) {
 921                                    window.blur();
 922                                }
 923                            })
 924                            .unwrap();
 925                    }
 926                    false
 927                } else {
 928                    true
 929                }
 930            });
 931    }
 932
 933    fn apply_notify_effect(&mut self, emitter: EntityId) {
 934        self.pending_notifications.remove(&emitter);
 935
 936        self.observers
 937            .clone()
 938            .retain(&emitter, |handler| handler(self));
 939    }
 940
 941    fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: Box<dyn Any>) {
 942        self.event_listeners
 943            .clone()
 944            .retain(&emitter, |(stored_type, handler)| {
 945                if *stored_type == event_type {
 946                    handler(event.as_ref(), self)
 947                } else {
 948                    true
 949                }
 950            });
 951    }
 952
 953    fn apply_refresh_effect(&mut self) {
 954        for window in self.windows.values_mut() {
 955            if let Some(window) = window.as_mut() {
 956                window.refreshing = true;
 957                window.invalidator.set_dirty(true);
 958            }
 959        }
 960    }
 961
 962    fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
 963        self.pending_global_notifications.remove(&type_id);
 964        self.global_observers
 965            .clone()
 966            .retain(&type_id, |observer| observer(self));
 967    }
 968
 969    fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
 970        callback(self);
 971    }
 972
 973    fn apply_entity_created_effect(
 974        &mut self,
 975        entity: AnyEntity,
 976        tid: TypeId,
 977        window: Option<WindowId>,
 978    ) {
 979        self.new_entity_observers.clone().retain(&tid, |observer| {
 980            if let Some(id) = window {
 981                self.update_window_id(id, {
 982                    let entity = entity.clone();
 983                    |_, window, cx| (observer)(entity, &mut Some(window), cx)
 984                })
 985                .expect("All windows should be off the stack when flushing effects");
 986            } else {
 987                (observer)(entity.clone(), &mut None, self)
 988            }
 989            true
 990        });
 991    }
 992
 993    fn update_window_id<T, F>(&mut self, id: WindowId, update: F) -> Result<T>
 994    where
 995        F: FnOnce(AnyView, &mut Window, &mut App) -> T,
 996    {
 997        self.update(|cx| {
 998            let mut window = cx
 999                .windows
1000                .get_mut(id)
1001                .ok_or_else(|| anyhow!("window not found"))?
1002                .take()
1003                .ok_or_else(|| anyhow!("window not found"))?;
1004
1005            let root_view = window.root.clone().unwrap();
1006
1007            cx.window_update_stack.push(window.handle.id);
1008            let result = update(root_view, &mut window, cx);
1009            cx.window_update_stack.pop();
1010
1011            if window.removed {
1012                cx.window_handles.remove(&id);
1013                cx.windows.remove(id);
1014
1015                cx.window_closed_observers.clone().retain(&(), |callback| {
1016                    callback(cx);
1017                    true
1018                });
1019            } else {
1020                cx.windows
1021                    .get_mut(id)
1022                    .ok_or_else(|| anyhow!("window not found"))?
1023                    .replace(window);
1024            }
1025
1026            Ok(result)
1027        })
1028    }
1029    /// Creates an `AsyncApp`, which can be cloned and has a static lifetime
1030    /// so it can be held across `await` points.
1031    pub fn to_async(&self) -> AsyncApp {
1032        AsyncApp {
1033            app: self.this.clone(),
1034            background_executor: self.background_executor.clone(),
1035            foreground_executor: self.foreground_executor.clone(),
1036        }
1037    }
1038
1039    /// Obtains a reference to the executor, which can be used to spawn futures.
1040    pub fn background_executor(&self) -> &BackgroundExecutor {
1041        &self.background_executor
1042    }
1043
1044    /// Obtains a reference to the executor, which can be used to spawn futures.
1045    pub fn foreground_executor(&self) -> &ForegroundExecutor {
1046        &self.foreground_executor
1047    }
1048
1049    /// Spawns the future returned by the given function on the main thread. The closure will be invoked
1050    /// with [AsyncApp], which allows the application state to be accessed across await points.
1051    #[track_caller]
1052    pub fn spawn<AsyncFn, R>(&self, f: AsyncFn) -> Task<R>
1053    where
1054        AsyncFn: AsyncFnOnce(&mut AsyncApp) -> R + 'static,
1055        R: 'static,
1056    {
1057        let mut cx = self.to_async();
1058        self.foreground_executor
1059            .spawn(async move { f(&mut cx).await })
1060    }
1061
1062    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1063    /// that are currently on the stack to be returned to the app.
1064    pub fn defer(&mut self, f: impl FnOnce(&mut App) + 'static) {
1065        self.push_effect(Effect::Defer {
1066            callback: Box::new(f),
1067        });
1068    }
1069
1070    /// Accessor for the application's asset source, which is provided when constructing the `App`.
1071    pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
1072        &self.asset_source
1073    }
1074
1075    /// Accessor for the text system.
1076    pub fn text_system(&self) -> &Arc<TextSystem> {
1077        &self.text_system
1078    }
1079
1080    /// Check whether a global of the given type has been assigned.
1081    pub fn has_global<G: Global>(&self) -> bool {
1082        self.globals_by_type.contains_key(&TypeId::of::<G>())
1083    }
1084
1085    /// Access the global of the given type. Panics if a global for that type has not been assigned.
1086    #[track_caller]
1087    pub fn global<G: Global>(&self) -> &G {
1088        self.globals_by_type
1089            .get(&TypeId::of::<G>())
1090            .map(|any_state| any_state.downcast_ref::<G>().unwrap())
1091            .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
1092            .unwrap()
1093    }
1094
1095    /// Access the global of the given type if a value has been assigned.
1096    pub fn try_global<G: Global>(&self) -> Option<&G> {
1097        self.globals_by_type
1098            .get(&TypeId::of::<G>())
1099            .map(|any_state| any_state.downcast_ref::<G>().unwrap())
1100    }
1101
1102    /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
1103    #[track_caller]
1104    pub fn global_mut<G: Global>(&mut self) -> &mut G {
1105        let global_type = TypeId::of::<G>();
1106        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1107        self.globals_by_type
1108            .get_mut(&global_type)
1109            .and_then(|any_state| any_state.downcast_mut::<G>())
1110            .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
1111            .unwrap()
1112    }
1113
1114    /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
1115    /// yet been assigned.
1116    pub fn default_global<G: Global + Default>(&mut self) -> &mut G {
1117        let global_type = TypeId::of::<G>();
1118        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1119        self.globals_by_type
1120            .entry(global_type)
1121            .or_insert_with(|| Box::<G>::default())
1122            .downcast_mut::<G>()
1123            .unwrap()
1124    }
1125
1126    /// Sets the value of the global of the given type.
1127    pub fn set_global<G: Global>(&mut self, global: G) {
1128        let global_type = TypeId::of::<G>();
1129        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1130        self.globals_by_type.insert(global_type, Box::new(global));
1131    }
1132
1133    /// Clear all stored globals. Does not notify global observers.
1134    #[cfg(any(test, feature = "test-support"))]
1135    pub fn clear_globals(&mut self) {
1136        self.globals_by_type.drain();
1137    }
1138
1139    /// Remove the global of the given type from the app context. Does not notify global observers.
1140    pub fn remove_global<G: Global>(&mut self) -> G {
1141        let global_type = TypeId::of::<G>();
1142        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1143        *self
1144            .globals_by_type
1145            .remove(&global_type)
1146            .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
1147            .downcast()
1148            .unwrap()
1149    }
1150
1151    /// Register a callback to be invoked when a global of the given type is updated.
1152    pub fn observe_global<G: Global>(
1153        &mut self,
1154        mut f: impl FnMut(&mut Self) + 'static,
1155    ) -> Subscription {
1156        let (subscription, activate) = self.global_observers.insert(
1157            TypeId::of::<G>(),
1158            Box::new(move |cx| {
1159                f(cx);
1160                true
1161            }),
1162        );
1163        self.defer(move |_| activate());
1164        subscription
1165    }
1166
1167    /// Move the global of the given type to the stack.
1168    #[track_caller]
1169    pub(crate) fn lease_global<G: Global>(&mut self) -> GlobalLease<G> {
1170        GlobalLease::new(
1171            self.globals_by_type
1172                .remove(&TypeId::of::<G>())
1173                .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
1174                .unwrap(),
1175        )
1176    }
1177
1178    /// Restore the global of the given type after it is moved to the stack.
1179    pub(crate) fn end_global_lease<G: Global>(&mut self, lease: GlobalLease<G>) {
1180        let global_type = TypeId::of::<G>();
1181
1182        self.push_effect(Effect::NotifyGlobalObservers { global_type });
1183        self.globals_by_type.insert(global_type, lease.global);
1184    }
1185
1186    pub(crate) fn new_entity_observer(
1187        &self,
1188        key: TypeId,
1189        value: NewEntityListener,
1190    ) -> Subscription {
1191        let (subscription, activate) = self.new_entity_observers.insert(key, value);
1192        activate();
1193        subscription
1194    }
1195
1196    /// Arrange for the given function to be invoked whenever a view of the specified type is created.
1197    /// The function will be passed a mutable reference to the view along with an appropriate context.
1198    pub fn observe_new<T: 'static>(
1199        &self,
1200        on_new: impl 'static + Fn(&mut T, Option<&mut Window>, &mut Context<T>),
1201    ) -> Subscription {
1202        self.new_entity_observer(
1203            TypeId::of::<T>(),
1204            Box::new(
1205                move |any_entity: AnyEntity, window: &mut Option<&mut Window>, cx: &mut App| {
1206                    any_entity
1207                        .downcast::<T>()
1208                        .unwrap()
1209                        .update(cx, |entity_state, cx| {
1210                            if let Some(window) = window {
1211                                on_new(entity_state, Some(window), cx);
1212                            } else {
1213                                on_new(entity_state, None, cx);
1214                            }
1215                        })
1216                },
1217            ),
1218        )
1219    }
1220
1221    /// Observe the release of a entity. The callback is invoked after the entity
1222    /// has no more strong references but before it has been dropped.
1223    pub fn observe_release<T>(
1224        &self,
1225        handle: &Entity<T>,
1226        on_release: impl FnOnce(&mut T, &mut App) + 'static,
1227    ) -> Subscription
1228    where
1229        T: 'static,
1230    {
1231        let (subscription, activate) = self.release_listeners.insert(
1232            handle.entity_id(),
1233            Box::new(move |entity, cx| {
1234                let entity = entity.downcast_mut().expect("invalid entity type");
1235                on_release(entity, cx)
1236            }),
1237        );
1238        activate();
1239        subscription
1240    }
1241
1242    /// Observe the release of a entity. The callback is invoked after the entity
1243    /// has no more strong references but before it has been dropped.
1244    pub fn observe_release_in<T>(
1245        &self,
1246        handle: &Entity<T>,
1247        window: &Window,
1248        on_release: impl FnOnce(&mut T, &mut Window, &mut App) + 'static,
1249    ) -> Subscription
1250    where
1251        T: 'static,
1252    {
1253        let window_handle = window.handle;
1254        self.observe_release(&handle, move |entity, cx| {
1255            let _ = window_handle.update(cx, |_, window, cx| on_release(entity, window, cx));
1256        })
1257    }
1258
1259    /// Register a callback to be invoked when a keystroke is received by the application
1260    /// in any window. Note that this fires after all other action and event mechanisms have resolved
1261    /// and that this API will not be invoked if the event's propagation is stopped.
1262    pub fn observe_keystrokes(
1263        &mut self,
1264        mut f: impl FnMut(&KeystrokeEvent, &mut Window, &mut App) + 'static,
1265    ) -> Subscription {
1266        fn inner(
1267            keystroke_observers: &SubscriberSet<(), KeystrokeObserver>,
1268            handler: KeystrokeObserver,
1269        ) -> Subscription {
1270            let (subscription, activate) = keystroke_observers.insert((), handler);
1271            activate();
1272            subscription
1273        }
1274
1275        inner(
1276            &mut self.keystroke_observers,
1277            Box::new(move |event, window, cx| {
1278                f(event, window, cx);
1279                true
1280            }),
1281        )
1282    }
1283
1284    /// Register key bindings.
1285    pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
1286        self.keymap.borrow_mut().add_bindings(bindings);
1287        self.pending_effects.push_back(Effect::RefreshWindows);
1288    }
1289
1290    /// Clear all key bindings in the app.
1291    pub fn clear_key_bindings(&mut self) {
1292        self.keymap.borrow_mut().clear();
1293        self.pending_effects.push_back(Effect::RefreshWindows);
1294    }
1295
1296    /// Register a global listener for actions invoked via the keyboard.
1297    pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
1298        self.global_action_listeners
1299            .entry(TypeId::of::<A>())
1300            .or_default()
1301            .push(Rc::new(move |action, phase, cx| {
1302                if phase == DispatchPhase::Bubble {
1303                    let action = action.downcast_ref().unwrap();
1304                    listener(action, cx)
1305                }
1306            }));
1307    }
1308
1309    /// Event handlers propagate events by default. Call this method to stop dispatching to
1310    /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
1311    /// the opposite of [`Self::propagate`]. It's also possible to cancel a call to [`Self::propagate`] by
1312    /// calling this method before effects are flushed.
1313    pub fn stop_propagation(&mut self) {
1314        self.propagate_event = false;
1315    }
1316
1317    /// Action handlers stop propagation by default during the bubble phase of action dispatch
1318    /// dispatching to action handlers higher in the element tree. This is the opposite of
1319    /// [`Self::stop_propagation`]. It's also possible to cancel a call to [`Self::stop_propagation`] by calling
1320    /// this method before effects are flushed.
1321    pub fn propagate(&mut self) {
1322        self.propagate_event = true;
1323    }
1324
1325    /// Build an action from some arbitrary data, typically a keymap entry.
1326    pub fn build_action(
1327        &self,
1328        name: &str,
1329        data: Option<serde_json::Value>,
1330    ) -> std::result::Result<Box<dyn Action>, ActionBuildError> {
1331        self.actions.build_action(name, data)
1332    }
1333
1334    /// Get all action names that have been registered. Note that registration only allows for
1335    /// actions to be built dynamically, and is unrelated to binding actions in the element tree.
1336    pub fn all_action_names(&self) -> &[SharedString] {
1337        self.actions.all_action_names()
1338    }
1339
1340    /// Returns key bindings that invoke the given action on the currently focused element, without
1341    /// checking context. Bindings are returned in the order they were added. For display, the last
1342    /// binding should take precedence.
1343    pub fn all_bindings_for_input(&self, input: &[Keystroke]) -> Vec<KeyBinding> {
1344        RefCell::borrow(&self.keymap).all_bindings_for_input(input)
1345    }
1346
1347    /// Get all non-internal actions that have been registered, along with their schemas.
1348    pub fn action_schemas(
1349        &self,
1350        generator: &mut schemars::r#gen::SchemaGenerator,
1351    ) -> Vec<(SharedString, Option<schemars::schema::Schema>)> {
1352        self.actions.action_schemas(generator)
1353    }
1354
1355    /// Get a list of all deprecated action aliases and their canonical names.
1356    pub fn action_deprecations(&self) -> &HashMap<SharedString, SharedString> {
1357        self.actions.action_deprecations()
1358    }
1359
1360    /// Register a callback to be invoked when the application is about to quit.
1361    /// It is not possible to cancel the quit event at this point.
1362    pub fn on_app_quit<Fut>(
1363        &self,
1364        mut on_quit: impl FnMut(&mut App) -> Fut + 'static,
1365    ) -> Subscription
1366    where
1367        Fut: 'static + Future<Output = ()>,
1368    {
1369        let (subscription, activate) = self.quit_observers.insert(
1370            (),
1371            Box::new(move |cx| {
1372                let future = on_quit(cx);
1373                future.boxed_local()
1374            }),
1375        );
1376        activate();
1377        subscription
1378    }
1379
1380    /// Register a callback to be invoked when a window is closed
1381    /// The window is no longer accessible at the point this callback is invoked.
1382    pub fn on_window_closed(&self, mut on_closed: impl FnMut(&mut App) + 'static) -> Subscription {
1383        let (subscription, activate) = self.window_closed_observers.insert((), Box::new(on_closed));
1384        activate();
1385        subscription
1386    }
1387
1388    pub(crate) fn clear_pending_keystrokes(&mut self) {
1389        for window in self.windows() {
1390            window
1391                .update(self, |_, window, _| {
1392                    window.clear_pending_keystrokes();
1393                })
1394                .ok();
1395        }
1396    }
1397
1398    /// Checks if the given action is bound in the current context, as defined by the app's current focus,
1399    /// the bindings in the element tree, and any global action listeners.
1400    pub fn is_action_available(&mut self, action: &dyn Action) -> bool {
1401        let mut action_available = false;
1402        if let Some(window) = self.active_window() {
1403            if let Ok(window_action_available) =
1404                window.update(self, |_, window, cx| window.is_action_available(action, cx))
1405            {
1406                action_available = window_action_available;
1407            }
1408        }
1409
1410        action_available
1411            || self
1412                .global_action_listeners
1413                .contains_key(&action.as_any().type_id())
1414    }
1415
1416    /// Sets the menu bar for this application. This will replace any existing menu bar.
1417    pub fn set_menus(&self, menus: Vec<Menu>) {
1418        self.platform.set_menus(menus, &self.keymap.borrow());
1419    }
1420
1421    /// Gets the menu bar for this application.
1422    pub fn get_menus(&self) -> Option<Vec<OwnedMenu>> {
1423        self.platform.get_menus()
1424    }
1425
1426    /// Sets the right click menu for the app icon in the dock
1427    pub fn set_dock_menu(&self, menus: Vec<MenuItem>) {
1428        self.platform.set_dock_menu(menus, &self.keymap.borrow());
1429    }
1430
1431    /// Performs the action associated with the given dock menu item, only used on Windows for now.
1432    pub fn perform_dock_menu_action(&self, action: usize) {
1433        self.platform.perform_dock_menu_action(action);
1434    }
1435
1436    /// Adds given path to the bottom of the list of recent paths for the application.
1437    /// The list is usually shown on the application icon's context menu in the dock,
1438    /// and allows to open the recent files via that context menu.
1439    /// If the path is already in the list, it will be moved to the bottom of the list.
1440    pub fn add_recent_document(&self, path: &Path) {
1441        self.platform.add_recent_document(path);
1442    }
1443
1444    /// Dispatch an action to the currently active window or global action handler
1445    /// See [`crate::Action`] for more information on how actions work
1446    pub fn dispatch_action(&mut self, action: &dyn Action) {
1447        if let Some(active_window) = self.active_window() {
1448            active_window
1449                .update(self, |_, window, cx| {
1450                    window.dispatch_action(action.boxed_clone(), cx)
1451                })
1452                .log_err();
1453        } else {
1454            self.dispatch_global_action(action);
1455        }
1456    }
1457
1458    fn dispatch_global_action(&mut self, action: &dyn Action) {
1459        self.propagate_event = true;
1460
1461        if let Some(mut global_listeners) = self
1462            .global_action_listeners
1463            .remove(&action.as_any().type_id())
1464        {
1465            for listener in &global_listeners {
1466                listener(action.as_any(), DispatchPhase::Capture, self);
1467                if !self.propagate_event {
1468                    break;
1469                }
1470            }
1471
1472            global_listeners.extend(
1473                self.global_action_listeners
1474                    .remove(&action.as_any().type_id())
1475                    .unwrap_or_default(),
1476            );
1477
1478            self.global_action_listeners
1479                .insert(action.as_any().type_id(), global_listeners);
1480        }
1481
1482        if self.propagate_event {
1483            if let Some(mut global_listeners) = self
1484                .global_action_listeners
1485                .remove(&action.as_any().type_id())
1486            {
1487                for listener in global_listeners.iter().rev() {
1488                    listener(action.as_any(), DispatchPhase::Bubble, self);
1489                    if !self.propagate_event {
1490                        break;
1491                    }
1492                }
1493
1494                global_listeners.extend(
1495                    self.global_action_listeners
1496                        .remove(&action.as_any().type_id())
1497                        .unwrap_or_default(),
1498                );
1499
1500                self.global_action_listeners
1501                    .insert(action.as_any().type_id(), global_listeners);
1502            }
1503        }
1504    }
1505
1506    /// Is there currently something being dragged?
1507    pub fn has_active_drag(&self) -> bool {
1508        self.active_drag.is_some()
1509    }
1510
1511    /// Set the prompt renderer for GPUI. This will replace the default or platform specific
1512    /// prompts with this custom implementation.
1513    pub fn set_prompt_builder(
1514        &mut self,
1515        renderer: impl Fn(
1516                PromptLevel,
1517                &str,
1518                Option<&str>,
1519                &[&str],
1520                PromptHandle,
1521                &mut Window,
1522                &mut App,
1523            ) -> RenderablePromptHandle
1524            + 'static,
1525    ) {
1526        self.prompt_builder = Some(PromptBuilder::Custom(Box::new(renderer)))
1527    }
1528
1529    /// Reset the prompt builder to the default implementation.
1530    pub fn reset_prompt_builder(&mut self) {
1531        self.prompt_builder = Some(PromptBuilder::Default);
1532    }
1533
1534    /// Remove an asset from GPUI's cache
1535    pub fn remove_asset<A: Asset>(&mut self, source: &A::Source) {
1536        let asset_id = (TypeId::of::<A>(), hash(source));
1537        self.loading_assets.remove(&asset_id);
1538    }
1539
1540    /// Asynchronously load an asset, if the asset hasn't finished loading this will return None.
1541    ///
1542    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
1543    /// time, and the results of this call will be cached
1544    pub fn fetch_asset<A: Asset>(&mut self, source: &A::Source) -> (Shared<Task<A::Output>>, bool) {
1545        let asset_id = (TypeId::of::<A>(), hash(source));
1546        let mut is_first = false;
1547        let task = self
1548            .loading_assets
1549            .remove(&asset_id)
1550            .map(|boxed_task| *boxed_task.downcast::<Shared<Task<A::Output>>>().unwrap())
1551            .unwrap_or_else(|| {
1552                is_first = true;
1553                let future = A::load(source.clone(), self);
1554                let task = self.background_executor().spawn(future).shared();
1555                task
1556            });
1557
1558        self.loading_assets.insert(asset_id, Box::new(task.clone()));
1559
1560        (task, is_first)
1561    }
1562
1563    /// Obtain a new [`FocusHandle`], which allows you to track and manipulate the keyboard focus
1564    /// for elements rendered within this window.
1565    #[track_caller]
1566    pub fn focus_handle(&self) -> FocusHandle {
1567        FocusHandle::new(&self.focus_handles)
1568    }
1569
1570    /// Tell GPUI that an entity has changed and observers of it should be notified.
1571    pub fn notify(&mut self, entity_id: EntityId) {
1572        let window_invalidators = mem::take(
1573            self.window_invalidators_by_entity
1574                .entry(entity_id)
1575                .or_default(),
1576        );
1577
1578        if window_invalidators.is_empty() {
1579            if self.pending_notifications.insert(entity_id) {
1580                self.pending_effects
1581                    .push_back(Effect::Notify { emitter: entity_id });
1582            }
1583        } else {
1584            for invalidator in window_invalidators.values() {
1585                invalidator.invalidate_view(entity_id, self);
1586            }
1587        }
1588
1589        self.window_invalidators_by_entity
1590            .insert(entity_id, window_invalidators);
1591    }
1592
1593    /// Returns the name for this [`App`].
1594    #[cfg(any(test, feature = "test-support", debug_assertions))]
1595    pub fn get_name(&self) -> Option<&'static str> {
1596        self.name
1597    }
1598
1599    /// Returns `true` if the platform file picker supports selecting a mix of files and directories.
1600    pub fn can_select_mixed_files_and_dirs(&self) -> bool {
1601        self.platform.can_select_mixed_files_and_dirs()
1602    }
1603}
1604
1605impl AppContext for App {
1606    type Result<T> = T;
1607
1608    /// Builds an entity that is owned by the application.
1609    ///
1610    /// The given function will be invoked with a [`Context`] and must return an object representing the entity. An
1611    /// [`Entity`] handle will be returned, which can be used to access the entity in a context.
1612    fn new<T: 'static>(&mut self, build_entity: impl FnOnce(&mut Context<T>) -> T) -> Entity<T> {
1613        self.update(|cx| {
1614            let slot = cx.entities.reserve();
1615            let handle = slot.clone();
1616            let entity = build_entity(&mut Context::new_context(cx, slot.downgrade()));
1617
1618            cx.push_effect(Effect::EntityCreated {
1619                entity: handle.clone().into_any(),
1620                tid: TypeId::of::<T>(),
1621                window: cx.window_update_stack.last().cloned(),
1622            });
1623
1624            cx.entities.insert(slot, entity);
1625            handle
1626        })
1627    }
1628
1629    fn reserve_entity<T: 'static>(&mut self) -> Self::Result<Reservation<T>> {
1630        Reservation(self.entities.reserve())
1631    }
1632
1633    fn insert_entity<T: 'static>(
1634        &mut self,
1635        reservation: Reservation<T>,
1636        build_entity: impl FnOnce(&mut Context<T>) -> T,
1637    ) -> Self::Result<Entity<T>> {
1638        self.update(|cx| {
1639            let slot = reservation.0;
1640            let entity = build_entity(&mut Context::new_context(cx, slot.downgrade()));
1641            cx.entities.insert(slot, entity)
1642        })
1643    }
1644
1645    /// Updates the entity referenced by the given handle. The function is passed a mutable reference to the
1646    /// entity along with a `Context` for the entity.
1647    fn update_entity<T: 'static, R>(
1648        &mut self,
1649        handle: &Entity<T>,
1650        update: impl FnOnce(&mut T, &mut Context<T>) -> R,
1651    ) -> R {
1652        self.update(|cx| {
1653            let mut entity = cx.entities.lease(handle);
1654            let result = update(
1655                &mut entity,
1656                &mut Context::new_context(cx, handle.downgrade()),
1657            );
1658            cx.entities.end_lease(entity);
1659            result
1660        })
1661    }
1662
1663    fn read_entity<T, R>(
1664        &self,
1665        handle: &Entity<T>,
1666        read: impl FnOnce(&T, &App) -> R,
1667    ) -> Self::Result<R>
1668    where
1669        T: 'static,
1670    {
1671        let entity = self.entities.read(handle);
1672        read(entity, self)
1673    }
1674
1675    fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
1676    where
1677        F: FnOnce(AnyView, &mut Window, &mut App) -> T,
1678    {
1679        self.update_window_id(handle.id, update)
1680    }
1681
1682    fn read_window<T, R>(
1683        &self,
1684        window: &WindowHandle<T>,
1685        read: impl FnOnce(Entity<T>, &App) -> R,
1686    ) -> Result<R>
1687    where
1688        T: 'static,
1689    {
1690        let window = self
1691            .windows
1692            .get(window.id)
1693            .ok_or_else(|| anyhow!("window not found"))?
1694            .as_ref()
1695            .expect("attempted to read a window that is already on the stack");
1696
1697        let root_view = window.root.clone().unwrap();
1698        let view = root_view
1699            .downcast::<T>()
1700            .map_err(|_| anyhow!("root view's type has changed"))?;
1701
1702        Ok(read(view, self))
1703    }
1704
1705    fn background_spawn<R>(&self, future: impl Future<Output = R> + Send + 'static) -> Task<R>
1706    where
1707        R: Send + 'static,
1708    {
1709        self.background_executor.spawn(future)
1710    }
1711
1712    fn read_global<G, R>(&self, callback: impl FnOnce(&G, &App) -> R) -> Self::Result<R>
1713    where
1714        G: Global,
1715    {
1716        let mut g = self.global::<G>();
1717        callback(&g, self)
1718    }
1719}
1720
1721/// These effects are processed at the end of each application update cycle.
1722pub(crate) enum Effect {
1723    Notify {
1724        emitter: EntityId,
1725    },
1726    Emit {
1727        emitter: EntityId,
1728        event_type: TypeId,
1729        event: Box<dyn Any>,
1730    },
1731    RefreshWindows,
1732    NotifyGlobalObservers {
1733        global_type: TypeId,
1734    },
1735    Defer {
1736        callback: Box<dyn FnOnce(&mut App) + 'static>,
1737    },
1738    EntityCreated {
1739        entity: AnyEntity,
1740        tid: TypeId,
1741        window: Option<WindowId>,
1742    },
1743}
1744
1745impl std::fmt::Debug for Effect {
1746    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1747        match self {
1748            Effect::Notify { emitter } => write!(f, "Notify({})", emitter),
1749            Effect::Emit { emitter, .. } => write!(f, "Emit({:?})", emitter),
1750            Effect::RefreshWindows => write!(f, "RefreshWindows"),
1751            Effect::NotifyGlobalObservers { global_type } => {
1752                write!(f, "NotifyGlobalObservers({:?})", global_type)
1753            }
1754            Effect::Defer { .. } => write!(f, "Defer(..)"),
1755            Effect::EntityCreated { entity, .. } => write!(f, "EntityCreated({:?})", entity),
1756        }
1757    }
1758}
1759
1760/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
1761pub(crate) struct GlobalLease<G: Global> {
1762    global: Box<dyn Any>,
1763    global_type: PhantomData<G>,
1764}
1765
1766impl<G: Global> GlobalLease<G> {
1767    fn new(global: Box<dyn Any>) -> Self {
1768        GlobalLease {
1769            global,
1770            global_type: PhantomData,
1771        }
1772    }
1773}
1774
1775impl<G: Global> Deref for GlobalLease<G> {
1776    type Target = G;
1777
1778    fn deref(&self) -> &Self::Target {
1779        self.global.downcast_ref().unwrap()
1780    }
1781}
1782
1783impl<G: Global> DerefMut for GlobalLease<G> {
1784    fn deref_mut(&mut self) -> &mut Self::Target {
1785        self.global.downcast_mut().unwrap()
1786    }
1787}
1788
1789/// Contains state associated with an active drag operation, started by dragging an element
1790/// within the window or by dragging into the app from the underlying platform.
1791pub struct AnyDrag {
1792    /// The view used to render this drag
1793    pub view: AnyView,
1794
1795    /// The value of the dragged item, to be dropped
1796    pub value: Arc<dyn Any>,
1797
1798    /// This is used to render the dragged item in the same place
1799    /// on the original element that the drag was initiated
1800    pub cursor_offset: Point<Pixels>,
1801}
1802
1803/// Contains state associated with a tooltip. You'll only need this struct if you're implementing
1804/// tooltip behavior on a custom element. Otherwise, use [Div::tooltip].
1805#[derive(Clone)]
1806pub struct AnyTooltip {
1807    /// The view used to display the tooltip
1808    pub view: AnyView,
1809
1810    /// The absolute position of the mouse when the tooltip was deployed.
1811    pub mouse_position: Point<Pixels>,
1812
1813    /// Given the bounds of the tooltip, checks whether the tooltip should still be visible and
1814    /// updates its state accordingly. This is needed atop the hovered element's mouse move handler
1815    /// to handle the case where the element is not painted (e.g. via use of `visible_on_hover`).
1816    pub check_visible_and_update: Rc<dyn Fn(Bounds<Pixels>, &mut Window, &mut App) -> bool>,
1817}
1818
1819/// A keystroke event, and potentially the associated action
1820#[derive(Debug)]
1821pub struct KeystrokeEvent {
1822    /// The keystroke that occurred
1823    pub keystroke: Keystroke,
1824
1825    /// The action that was resolved for the keystroke, if any
1826    pub action: Option<Box<dyn Action>>,
1827}
1828
1829struct NullHttpClient;
1830
1831impl HttpClient for NullHttpClient {
1832    fn send(
1833        &self,
1834        _req: http_client::Request<http_client::AsyncBody>,
1835    ) -> futures::future::BoxFuture<
1836        'static,
1837        Result<http_client::Response<http_client::AsyncBody>, anyhow::Error>,
1838    > {
1839        async move { Err(anyhow!("No HttpClient available")) }.boxed()
1840    }
1841
1842    fn proxy(&self) -> Option<&http_client::Uri> {
1843        None
1844    }
1845
1846    fn type_name(&self) -> &'static str {
1847        type_name::<Self>()
1848    }
1849}