app.rs

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