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