app.rs

   1pub mod action;
   2mod callback_collection;
   3mod menu;
   4pub(crate) mod ref_counts;
   5#[cfg(any(test, feature = "test-support"))]
   6pub mod test_app_context;
   7mod window_input_handler;
   8
   9use std::{
  10    any::{type_name, Any, TypeId},
  11    cell::RefCell,
  12    fmt::{self, Debug},
  13    hash::{Hash, Hasher},
  14    marker::PhantomData,
  15    mem,
  16    ops::{Deref, DerefMut, Range},
  17    path::{Path, PathBuf},
  18    pin::Pin,
  19    rc::{self, Rc},
  20    sync::{Arc, Weak},
  21    time::Duration,
  22};
  23
  24use anyhow::{anyhow, Context, Result};
  25use parking_lot::Mutex;
  26use pathfinder_geometry::vector::Vector2F;
  27use postage::oneshot;
  28use smallvec::SmallVec;
  29use smol::prelude::*;
  30use uuid::Uuid;
  31
  32pub use action::*;
  33use callback_collection::CallbackCollection;
  34use collections::{hash_map::Entry, BTreeMap, HashMap, HashSet, VecDeque};
  35pub use menu::*;
  36use platform::Event;
  37#[cfg(any(test, feature = "test-support"))]
  38use ref_counts::LeakDetector;
  39#[cfg(any(test, feature = "test-support"))]
  40pub use test_app_context::{ContextHandle, TestAppContext};
  41use window_input_handler::WindowInputHandler;
  42
  43use crate::{
  44    elements::ElementBox,
  45    executor::{self, Task},
  46    keymap_matcher::{self, Binding, KeymapContext, KeymapMatcher, Keystroke, MatchResult},
  47    platform::{self, KeyDownEvent, Platform, PromptLevel, WindowOptions},
  48    presenter::Presenter,
  49    util::post_inc,
  50    Appearance, AssetCache, AssetSource, ClipboardItem, FontCache, KeyUpEvent,
  51    ModifiersChangedEvent, MouseButton, MouseRegionId, PathPromptOptions, TextLayoutCache,
  52    WindowBounds,
  53};
  54
  55use self::ref_counts::RefCounts;
  56
  57pub trait Entity: 'static {
  58    type Event;
  59
  60    fn release(&mut self, _: &mut AppContext) {}
  61    fn app_will_quit(
  62        &mut self,
  63        _: &mut AppContext,
  64    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
  65        None
  66    }
  67}
  68
  69pub trait View: Entity + Sized {
  70    fn ui_name() -> &'static str;
  71    fn render(&mut self, cx: &mut RenderContext<'_, Self>) -> ElementBox;
  72    fn focus_in(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  73    fn focus_out(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  74    fn key_down(&mut self, _: &KeyDownEvent, _: &mut ViewContext<Self>) -> bool {
  75        false
  76    }
  77    fn key_up(&mut self, _: &KeyUpEvent, _: &mut ViewContext<Self>) -> bool {
  78        false
  79    }
  80    fn modifiers_changed(&mut self, _: &ModifiersChangedEvent, _: &mut ViewContext<Self>) -> bool {
  81        false
  82    }
  83
  84    fn keymap_context(&self, _: &AppContext) -> keymap_matcher::KeymapContext {
  85        Self::default_keymap_context()
  86    }
  87    fn default_keymap_context() -> keymap_matcher::KeymapContext {
  88        let mut cx = keymap_matcher::KeymapContext::default();
  89        cx.add_identifier(Self::ui_name());
  90        cx
  91    }
  92    fn debug_json(&self, _: &AppContext) -> serde_json::Value {
  93        serde_json::Value::Null
  94    }
  95
  96    fn text_for_range(&self, _: Range<usize>, _: &AppContext) -> Option<String> {
  97        None
  98    }
  99    fn selected_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
 100        None
 101    }
 102    fn marked_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
 103        None
 104    }
 105    fn unmark_text(&mut self, _: &mut ViewContext<Self>) {}
 106    fn replace_text_in_range(
 107        &mut self,
 108        _: Option<Range<usize>>,
 109        _: &str,
 110        _: &mut ViewContext<Self>,
 111    ) {
 112    }
 113    fn replace_and_mark_text_in_range(
 114        &mut self,
 115        _: Option<Range<usize>>,
 116        _: &str,
 117        _: Option<Range<usize>>,
 118        _: &mut ViewContext<Self>,
 119    ) {
 120    }
 121}
 122
 123pub trait ReadModel {
 124    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T;
 125}
 126
 127pub trait ReadModelWith {
 128    fn read_model_with<E: Entity, T>(
 129        &self,
 130        handle: &ModelHandle<E>,
 131        read: &mut dyn FnMut(&E, &AppContext) -> T,
 132    ) -> T;
 133}
 134
 135pub trait UpdateModel {
 136    fn update_model<T: Entity, O>(
 137        &mut self,
 138        handle: &ModelHandle<T>,
 139        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
 140    ) -> O;
 141}
 142
 143pub trait UpgradeModelHandle {
 144    fn upgrade_model_handle<T: Entity>(
 145        &self,
 146        handle: &WeakModelHandle<T>,
 147    ) -> Option<ModelHandle<T>>;
 148
 149    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool;
 150
 151    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle>;
 152}
 153
 154pub trait UpgradeViewHandle {
 155    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>>;
 156
 157    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle>;
 158}
 159
 160pub trait ReadView {
 161    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T;
 162}
 163
 164pub trait ReadViewWith {
 165    fn read_view_with<V, T>(
 166        &self,
 167        handle: &ViewHandle<V>,
 168        read: &mut dyn FnMut(&V, &AppContext) -> T,
 169    ) -> T
 170    where
 171        V: View;
 172}
 173
 174pub trait UpdateView {
 175    fn update_view<T, S>(
 176        &mut self,
 177        handle: &ViewHandle<T>,
 178        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
 179    ) -> S
 180    where
 181        T: View;
 182}
 183
 184#[derive(Clone)]
 185pub struct App(Rc<RefCell<AppContext>>);
 186
 187#[derive(Clone)]
 188pub struct AsyncAppContext(Rc<RefCell<AppContext>>);
 189
 190impl App {
 191    pub fn new(asset_source: impl AssetSource) -> Result<Self> {
 192        let platform = platform::current::platform();
 193        let foreground = Rc::new(executor::Foreground::platform(platform.dispatcher())?);
 194        let foreground_platform = platform::current::foreground_platform(foreground.clone());
 195        let app = Self(Rc::new(RefCell::new(AppContext::new(
 196            foreground,
 197            Arc::new(executor::Background::new()),
 198            platform.clone(),
 199            foreground_platform.clone(),
 200            Arc::new(FontCache::new(platform.fonts())),
 201            Default::default(),
 202            asset_source,
 203        ))));
 204
 205        foreground_platform.on_quit(Box::new({
 206            let cx = app.0.clone();
 207            move || {
 208                cx.borrow_mut().quit();
 209            }
 210        }));
 211        setup_menu_handlers(foreground_platform.as_ref(), &app);
 212
 213        app.0.borrow_mut().weak_self = Some(Rc::downgrade(&app.0));
 214        Ok(app)
 215    }
 216
 217    pub fn background(&self) -> Arc<executor::Background> {
 218        self.0.borrow().background().clone()
 219    }
 220
 221    pub fn on_become_active<F>(self, mut callback: F) -> Self
 222    where
 223        F: 'static + FnMut(&mut AppContext),
 224    {
 225        let cx = self.0.clone();
 226        self.0
 227            .borrow_mut()
 228            .foreground_platform
 229            .on_become_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 230        self
 231    }
 232
 233    pub fn on_resign_active<F>(self, mut callback: F) -> Self
 234    where
 235        F: 'static + FnMut(&mut AppContext),
 236    {
 237        let cx = self.0.clone();
 238        self.0
 239            .borrow_mut()
 240            .foreground_platform
 241            .on_resign_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 242        self
 243    }
 244
 245    pub fn on_quit<F>(&mut self, mut callback: F) -> &mut Self
 246    where
 247        F: 'static + FnMut(&mut AppContext),
 248    {
 249        let cx = self.0.clone();
 250        self.0
 251            .borrow_mut()
 252            .foreground_platform
 253            .on_quit(Box::new(move || callback(&mut *cx.borrow_mut())));
 254        self
 255    }
 256
 257    /// Handle the application being re-activated when no windows are open.
 258    pub fn on_reopen<F>(&mut self, mut callback: F) -> &mut Self
 259    where
 260        F: 'static + FnMut(&mut AppContext),
 261    {
 262        let cx = self.0.clone();
 263        self.0
 264            .borrow_mut()
 265            .foreground_platform
 266            .on_reopen(Box::new(move || callback(&mut *cx.borrow_mut())));
 267        self
 268    }
 269
 270    pub fn on_event<F>(&mut self, mut callback: F) -> &mut Self
 271    where
 272        F: 'static + FnMut(Event, &mut AppContext) -> bool,
 273    {
 274        let cx = self.0.clone();
 275        self.0
 276            .borrow_mut()
 277            .foreground_platform
 278            .on_event(Box::new(move |event| {
 279                callback(event, &mut *cx.borrow_mut())
 280            }));
 281        self
 282    }
 283
 284    pub fn on_open_urls<F>(&mut self, mut callback: F) -> &mut Self
 285    where
 286        F: 'static + FnMut(Vec<String>, &mut AppContext),
 287    {
 288        let cx = self.0.clone();
 289        self.0
 290            .borrow_mut()
 291            .foreground_platform
 292            .on_open_urls(Box::new(move |urls| callback(urls, &mut *cx.borrow_mut())));
 293        self
 294    }
 295
 296    pub fn run<F>(self, on_finish_launching: F)
 297    where
 298        F: 'static + FnOnce(&mut AppContext),
 299    {
 300        let platform = self.0.borrow().foreground_platform.clone();
 301        platform.run(Box::new(move || {
 302            let mut cx = self.0.borrow_mut();
 303            let cx = &mut *cx;
 304            crate::views::init(cx);
 305            on_finish_launching(cx);
 306        }))
 307    }
 308
 309    pub fn platform(&self) -> Arc<dyn Platform> {
 310        self.0.borrow().platform.clone()
 311    }
 312
 313    pub fn font_cache(&self) -> Arc<FontCache> {
 314        self.0.borrow().font_cache.clone()
 315    }
 316
 317    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, callback: F) -> T {
 318        let mut state = self.0.borrow_mut();
 319        let result = state.update(callback);
 320        state.pending_notifications.clear();
 321        result
 322    }
 323}
 324
 325impl AsyncAppContext {
 326    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
 327    where
 328        F: FnOnce(AsyncAppContext) -> Fut,
 329        Fut: 'static + Future<Output = T>,
 330        T: 'static,
 331    {
 332        self.0.borrow().foreground.spawn(f(self.clone()))
 333    }
 334
 335    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 336        callback(&*self.0.borrow())
 337    }
 338
 339    pub fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, callback: F) -> T {
 340        self.0.borrow_mut().update(callback)
 341    }
 342
 343    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 344    where
 345        T: Entity,
 346        F: FnOnce(&mut ModelContext<T>) -> T,
 347    {
 348        self.update(|cx| cx.add_model(build_model))
 349    }
 350
 351    pub fn add_window<T, F>(
 352        &mut self,
 353        window_options: WindowOptions,
 354        build_root_view: F,
 355    ) -> (usize, ViewHandle<T>)
 356    where
 357        T: View,
 358        F: FnOnce(&mut ViewContext<T>) -> T,
 359    {
 360        self.update(|cx| cx.add_window(window_options, build_root_view))
 361    }
 362
 363    pub fn remove_window(&mut self, window_id: usize) {
 364        self.update(|cx| cx.remove_window(window_id))
 365    }
 366
 367    pub fn activate_window(&mut self, window_id: usize) {
 368        self.update(|cx| cx.activate_window(window_id))
 369    }
 370
 371    pub fn prompt(
 372        &mut self,
 373        window_id: usize,
 374        level: PromptLevel,
 375        msg: &str,
 376        answers: &[&str],
 377    ) -> oneshot::Receiver<usize> {
 378        self.update(|cx| cx.prompt(window_id, level, msg, answers))
 379    }
 380
 381    pub fn platform(&self) -> Arc<dyn Platform> {
 382        self.0.borrow().platform().clone()
 383    }
 384
 385    pub fn foreground(&self) -> Rc<executor::Foreground> {
 386        self.0.borrow().foreground.clone()
 387    }
 388
 389    pub fn background(&self) -> Arc<executor::Background> {
 390        self.0.borrow().background.clone()
 391    }
 392}
 393
 394impl UpdateModel for AsyncAppContext {
 395    fn update_model<E: Entity, O>(
 396        &mut self,
 397        handle: &ModelHandle<E>,
 398        update: &mut dyn FnMut(&mut E, &mut ModelContext<E>) -> O,
 399    ) -> O {
 400        self.0.borrow_mut().update_model(handle, update)
 401    }
 402}
 403
 404impl UpgradeModelHandle for AsyncAppContext {
 405    fn upgrade_model_handle<T: Entity>(
 406        &self,
 407        handle: &WeakModelHandle<T>,
 408    ) -> Option<ModelHandle<T>> {
 409        self.0.borrow().upgrade_model_handle(handle)
 410    }
 411
 412    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
 413        self.0.borrow().model_handle_is_upgradable(handle)
 414    }
 415
 416    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
 417        self.0.borrow().upgrade_any_model_handle(handle)
 418    }
 419}
 420
 421impl UpgradeViewHandle for AsyncAppContext {
 422    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
 423        self.0.borrow_mut().upgrade_view_handle(handle)
 424    }
 425
 426    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
 427        self.0.borrow_mut().upgrade_any_view_handle(handle)
 428    }
 429}
 430
 431impl ReadModelWith for AsyncAppContext {
 432    fn read_model_with<E: Entity, T>(
 433        &self,
 434        handle: &ModelHandle<E>,
 435        read: &mut dyn FnMut(&E, &AppContext) -> T,
 436    ) -> T {
 437        let cx = self.0.borrow();
 438        let cx = &*cx;
 439        read(handle.read(cx), cx)
 440    }
 441}
 442
 443impl UpdateView for AsyncAppContext {
 444    fn update_view<T, S>(
 445        &mut self,
 446        handle: &ViewHandle<T>,
 447        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
 448    ) -> S
 449    where
 450        T: View,
 451    {
 452        self.0.borrow_mut().update_view(handle, update)
 453    }
 454}
 455
 456impl ReadViewWith for AsyncAppContext {
 457    fn read_view_with<V, T>(
 458        &self,
 459        handle: &ViewHandle<V>,
 460        read: &mut dyn FnMut(&V, &AppContext) -> T,
 461    ) -> T
 462    where
 463        V: View,
 464    {
 465        let cx = self.0.borrow();
 466        let cx = &*cx;
 467        read(handle.read(cx), cx)
 468    }
 469}
 470
 471type ActionCallback = dyn FnMut(&mut dyn AnyView, &dyn Action, &mut AppContext, usize, usize);
 472type GlobalActionCallback = dyn FnMut(&dyn Action, &mut AppContext);
 473
 474type SubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool>;
 475type GlobalSubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut AppContext)>;
 476type ObservationCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 477type GlobalObservationCallback = Box<dyn FnMut(&mut AppContext)>;
 478type FocusObservationCallback = Box<dyn FnMut(bool, &mut AppContext) -> bool>;
 479type ReleaseObservationCallback = Box<dyn FnMut(&dyn Any, &mut AppContext)>;
 480type ActionObservationCallback = Box<dyn FnMut(TypeId, &mut AppContext)>;
 481type WindowActivationCallback = Box<dyn FnMut(bool, &mut AppContext) -> bool>;
 482type WindowFullscreenCallback = Box<dyn FnMut(bool, &mut AppContext) -> bool>;
 483type WindowBoundsCallback = Box<dyn FnMut(WindowBounds, Uuid, &mut AppContext) -> bool>;
 484type KeystrokeCallback =
 485    Box<dyn FnMut(&Keystroke, &MatchResult, Option<&Box<dyn Action>>, &mut AppContext) -> bool>;
 486type ActiveLabeledTasksCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 487type DeserializeActionCallback = fn(json: &str) -> anyhow::Result<Box<dyn Action>>;
 488type WindowShouldCloseSubscriptionCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 489
 490pub struct AppContext {
 491    models: HashMap<usize, Box<dyn AnyModel>>,
 492    views: HashMap<(usize, usize), Box<dyn AnyView>>,
 493    pub(crate) parents: HashMap<(usize, usize), ParentId>,
 494    windows: HashMap<usize, Window>,
 495    globals: HashMap<TypeId, Box<dyn Any>>,
 496    element_states: HashMap<ElementStateId, Box<dyn Any>>,
 497    background: Arc<executor::Background>,
 498    ref_counts: Arc<Mutex<RefCounts>>,
 499    font_cache: Arc<FontCache>,
 500    platform: Arc<dyn Platform>,
 501
 502    weak_self: Option<rc::Weak<RefCell<Self>>>,
 503    foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 504    assets: Arc<AssetCache>,
 505    action_deserializers: HashMap<&'static str, (TypeId, DeserializeActionCallback)>,
 506    capture_actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 507    // Entity Types -> { Action Types -> Action Handlers }
 508    actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 509    // Action Types -> Action Handlers
 510    global_actions: HashMap<TypeId, Box<GlobalActionCallback>>,
 511    keystroke_matcher: KeymapMatcher,
 512    next_entity_id: usize,
 513    next_window_id: usize,
 514    next_subscription_id: usize,
 515    frame_count: usize,
 516
 517    subscriptions: CallbackCollection<usize, SubscriptionCallback>,
 518    global_subscriptions: CallbackCollection<TypeId, GlobalSubscriptionCallback>,
 519    observations: CallbackCollection<usize, ObservationCallback>,
 520    global_observations: CallbackCollection<TypeId, GlobalObservationCallback>,
 521    focus_observations: CallbackCollection<usize, FocusObservationCallback>,
 522    release_observations: CallbackCollection<usize, ReleaseObservationCallback>,
 523    action_dispatch_observations: CallbackCollection<(), ActionObservationCallback>,
 524    window_activation_observations: CallbackCollection<usize, WindowActivationCallback>,
 525    window_fullscreen_observations: CallbackCollection<usize, WindowFullscreenCallback>,
 526    window_bounds_observations: CallbackCollection<usize, WindowBoundsCallback>,
 527    keystroke_observations: CallbackCollection<usize, KeystrokeCallback>,
 528    active_labeled_task_observations: CallbackCollection<(), ActiveLabeledTasksCallback>,
 529
 530    #[allow(clippy::type_complexity)]
 531    presenters_and_platform_windows:
 532        HashMap<usize, (Rc<RefCell<Presenter>>, Box<dyn platform::Window>)>,
 533    foreground: Rc<executor::Foreground>,
 534    pending_effects: VecDeque<Effect>,
 535    pending_notifications: HashSet<usize>,
 536    pending_global_notifications: HashSet<TypeId>,
 537    pending_flushes: usize,
 538    flushing_effects: bool,
 539    halt_action_dispatch: bool,
 540    next_labeled_task_id: usize,
 541    active_labeled_tasks: BTreeMap<usize, &'static str>,
 542}
 543
 544impl AppContext {
 545    fn new(
 546        foreground: Rc<executor::Foreground>,
 547        background: Arc<executor::Background>,
 548        platform: Arc<dyn platform::Platform>,
 549        foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 550        font_cache: Arc<FontCache>,
 551        ref_counts: RefCounts,
 552        asset_source: impl AssetSource,
 553    ) -> Self {
 554        Self {
 555            models: Default::default(),
 556            views: Default::default(),
 557            parents: Default::default(),
 558            windows: Default::default(),
 559            globals: Default::default(),
 560            element_states: Default::default(),
 561            ref_counts: Arc::new(Mutex::new(ref_counts)),
 562            background,
 563            font_cache,
 564            platform,
 565
 566            weak_self: None,
 567            foreground_platform,
 568            assets: Arc::new(AssetCache::new(asset_source)),
 569            action_deserializers: Default::default(),
 570            capture_actions: Default::default(),
 571            actions: Default::default(),
 572            global_actions: Default::default(),
 573            keystroke_matcher: KeymapMatcher::default(),
 574            next_entity_id: 0,
 575            next_window_id: 0,
 576            next_subscription_id: 0,
 577            frame_count: 0,
 578            subscriptions: Default::default(),
 579            global_subscriptions: Default::default(),
 580            observations: Default::default(),
 581            focus_observations: Default::default(),
 582            release_observations: Default::default(),
 583            global_observations: Default::default(),
 584            window_activation_observations: Default::default(),
 585            window_fullscreen_observations: Default::default(),
 586            window_bounds_observations: Default::default(),
 587            keystroke_observations: Default::default(),
 588            action_dispatch_observations: Default::default(),
 589            active_labeled_task_observations: Default::default(),
 590            presenters_and_platform_windows: Default::default(),
 591            foreground,
 592            pending_effects: VecDeque::new(),
 593            pending_notifications: Default::default(),
 594            pending_global_notifications: Default::default(),
 595            pending_flushes: 0,
 596            flushing_effects: false,
 597            halt_action_dispatch: false,
 598            next_labeled_task_id: 0,
 599            active_labeled_tasks: Default::default(),
 600        }
 601    }
 602
 603    pub fn upgrade(&self) -> App {
 604        App(self.weak_self.as_ref().unwrap().upgrade().unwrap())
 605    }
 606
 607    pub fn quit(&mut self) {
 608        let mut futures = Vec::new();
 609
 610        self.update(|cx| {
 611            for model_id in cx.models.keys().copied().collect::<Vec<_>>() {
 612                let mut model = cx.models.remove(&model_id).unwrap();
 613                futures.extend(model.app_will_quit(cx));
 614                cx.models.insert(model_id, model);
 615            }
 616
 617            for view_id in cx.views.keys().copied().collect::<Vec<_>>() {
 618                let mut view = cx.views.remove(&view_id).unwrap();
 619                futures.extend(view.app_will_quit(cx));
 620                cx.views.insert(view_id, view);
 621            }
 622        });
 623
 624        self.remove_all_windows();
 625
 626        let futures = futures::future::join_all(futures);
 627        if self
 628            .background
 629            .block_with_timeout(Duration::from_millis(100), futures)
 630            .is_err()
 631        {
 632            log::error!("timed out waiting on app_will_quit");
 633        }
 634    }
 635
 636    pub fn remove_all_windows(&mut self) {
 637        for (window_id, _) in self.windows.drain() {
 638            self.presenters_and_platform_windows.remove(&window_id);
 639        }
 640        self.flush_effects();
 641    }
 642
 643    pub fn foreground(&self) -> &Rc<executor::Foreground> {
 644        &self.foreground
 645    }
 646
 647    pub fn debug_elements(&self, window_id: usize) -> Option<crate::json::Value> {
 648        self.presenters_and_platform_windows
 649            .get(&window_id)
 650            .and_then(|(presenter, _)| presenter.borrow().debug_elements(self))
 651    }
 652
 653    pub fn deserialize_action(
 654        &self,
 655        name: &str,
 656        argument: Option<&str>,
 657    ) -> Result<Box<dyn Action>> {
 658        let callback = self
 659            .action_deserializers
 660            .get(name)
 661            .ok_or_else(|| anyhow!("unknown action {}", name))?
 662            .1;
 663        callback(argument.unwrap_or("{}"))
 664            .with_context(|| format!("invalid data for action {}", name))
 665    }
 666
 667    pub fn add_action<A, V, F, R>(&mut self, handler: F)
 668    where
 669        A: Action,
 670        V: View,
 671        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> R,
 672    {
 673        self.add_action_internal(handler, false)
 674    }
 675
 676    pub fn capture_action<A, V, F>(&mut self, handler: F)
 677    where
 678        A: Action,
 679        V: View,
 680        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
 681    {
 682        self.add_action_internal(handler, true)
 683    }
 684
 685    fn add_action_internal<A, V, F, R>(&mut self, mut handler: F, capture: bool)
 686    where
 687        A: Action,
 688        V: View,
 689        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> R,
 690    {
 691        let handler = Box::new(
 692            move |view: &mut dyn AnyView,
 693                  action: &dyn Action,
 694                  cx: &mut AppContext,
 695                  window_id: usize,
 696                  view_id: usize| {
 697                let action = action.as_any().downcast_ref().unwrap();
 698                let mut cx = ViewContext::new(cx, window_id, view_id);
 699                handler(
 700                    view.as_any_mut()
 701                        .downcast_mut()
 702                        .expect("downcast is type safe"),
 703                    action,
 704                    &mut cx,
 705                );
 706            },
 707        );
 708
 709        self.action_deserializers
 710            .entry(A::qualified_name())
 711            .or_insert((TypeId::of::<A>(), A::from_json_str));
 712
 713        let actions = if capture {
 714            &mut self.capture_actions
 715        } else {
 716            &mut self.actions
 717        };
 718
 719        actions
 720            .entry(TypeId::of::<V>())
 721            .or_default()
 722            .entry(TypeId::of::<A>())
 723            .or_default()
 724            .push(handler);
 725    }
 726
 727    pub fn add_async_action<A, V, F>(&mut self, mut handler: F)
 728    where
 729        A: Action,
 730        V: View,
 731        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> Option<Task<Result<()>>>,
 732    {
 733        self.add_action(move |view, action, cx| {
 734            if let Some(task) = handler(view, action, cx) {
 735                task.detach_and_log_err(cx);
 736            }
 737        })
 738    }
 739
 740    pub fn add_global_action<A, F>(&mut self, mut handler: F)
 741    where
 742        A: Action,
 743        F: 'static + FnMut(&A, &mut AppContext),
 744    {
 745        let handler = Box::new(move |action: &dyn Action, cx: &mut AppContext| {
 746            let action = action.as_any().downcast_ref().unwrap();
 747            handler(action, cx);
 748        });
 749
 750        self.action_deserializers
 751            .entry(A::qualified_name())
 752            .or_insert((TypeId::of::<A>(), A::from_json_str));
 753
 754        if self
 755            .global_actions
 756            .insert(TypeId::of::<A>(), handler)
 757            .is_some()
 758        {
 759            panic!(
 760                "registered multiple global handlers for {}",
 761                type_name::<A>()
 762            );
 763        }
 764    }
 765
 766    pub fn is_topmost_window_for_position(&self, window_id: usize, position: Vector2F) -> bool {
 767        self.presenters_and_platform_windows
 768            .get(&window_id)
 769            .map_or(false, |(_, window)| {
 770                window.is_topmost_for_position(position)
 771            })
 772    }
 773
 774    pub fn has_window(&self, window_id: usize) -> bool {
 775        self.window_ids()
 776            .find(|window| window == &window_id)
 777            .is_some()
 778    }
 779
 780    pub fn window_ids(&self) -> impl Iterator<Item = usize> + '_ {
 781        self.windows.keys().copied()
 782    }
 783
 784    pub fn activate_window(&self, window_id: usize) {
 785        if let Some((_, window)) = self.presenters_and_platform_windows.get(&window_id) {
 786            window.activate()
 787        }
 788    }
 789
 790    pub fn window_is_active(&self, window_id: usize) -> bool {
 791        self.windows
 792            .get(&window_id)
 793            .map_or(false, |window| window.is_active)
 794    }
 795
 796    pub fn window_is_fullscreen(&self, window_id: usize) -> bool {
 797        self.windows
 798            .get(&window_id)
 799            .map_or(false, |window| window.is_fullscreen)
 800    }
 801
 802    pub fn window_bounds(&self, window_id: usize) -> Option<WindowBounds> {
 803        let (_, window) = self.presenters_and_platform_windows.get(&window_id)?;
 804        Some(window.bounds())
 805    }
 806
 807    pub fn window_display_uuid(&self, window_id: usize) -> Option<Uuid> {
 808        let (_, window) = self.presenters_and_platform_windows.get(&window_id)?;
 809        window.screen().display_uuid()
 810    }
 811
 812    pub fn active_labeled_tasks<'a>(
 813        &'a self,
 814    ) -> impl DoubleEndedIterator<Item = &'static str> + 'a {
 815        self.active_labeled_tasks.values().cloned()
 816    }
 817
 818    pub fn render_view(&mut self, params: RenderParams) -> Result<ElementBox> {
 819        let window_id = params.window_id;
 820        let view_id = params.view_id;
 821        let mut view = self
 822            .views
 823            .remove(&(window_id, view_id))
 824            .ok_or_else(|| anyhow!("view not found"))?;
 825        let element = view.render(params, self);
 826        self.views.insert((window_id, view_id), view);
 827        Ok(element)
 828    }
 829
 830    pub fn render_views(
 831        &mut self,
 832        window_id: usize,
 833        titlebar_height: f32,
 834        appearance: Appearance,
 835    ) -> HashMap<usize, ElementBox> {
 836        self.start_frame();
 837        #[allow(clippy::needless_collect)]
 838        let view_ids = self
 839            .views
 840            .keys()
 841            .filter_map(|(win_id, view_id)| {
 842                if *win_id == window_id {
 843                    Some(*view_id)
 844                } else {
 845                    None
 846                }
 847            })
 848            .collect::<Vec<_>>();
 849
 850        view_ids
 851            .into_iter()
 852            .map(|view_id| {
 853                (
 854                    view_id,
 855                    self.render_view(RenderParams {
 856                        window_id,
 857                        view_id,
 858                        titlebar_height,
 859                        hovered_region_ids: Default::default(),
 860                        clicked_region_ids: None,
 861                        refreshing: false,
 862                        appearance,
 863                    })
 864                    .unwrap(),
 865                )
 866            })
 867            .collect()
 868    }
 869
 870    pub(crate) fn start_frame(&mut self) {
 871        self.frame_count += 1;
 872    }
 873
 874    pub fn update<T, F: FnOnce(&mut Self) -> T>(&mut self, callback: F) -> T {
 875        self.pending_flushes += 1;
 876        let result = callback(self);
 877        self.flush_effects();
 878        result
 879    }
 880
 881    fn show_character_palette(&self, window_id: usize) {
 882        let (_, window) = &self.presenters_and_platform_windows[&window_id];
 883        window.show_character_palette();
 884    }
 885
 886    pub fn minimize_window(&self, window_id: usize) {
 887        let (_, window) = &self.presenters_and_platform_windows[&window_id];
 888        window.minimize();
 889    }
 890
 891    pub fn zoom_window(&self, window_id: usize) {
 892        let (_, window) = &self.presenters_and_platform_windows[&window_id];
 893        window.zoom();
 894    }
 895
 896    pub fn toggle_window_full_screen(&self, window_id: usize) {
 897        let (_, window) = &self.presenters_and_platform_windows[&window_id];
 898        window.toggle_full_screen();
 899    }
 900
 901    pub fn prompt(
 902        &self,
 903        window_id: usize,
 904        level: PromptLevel,
 905        msg: &str,
 906        answers: &[&str],
 907    ) -> oneshot::Receiver<usize> {
 908        let (_, window) = &self.presenters_and_platform_windows[&window_id];
 909        window.prompt(level, msg, answers)
 910    }
 911
 912    pub fn prompt_for_paths(
 913        &self,
 914        options: PathPromptOptions,
 915    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
 916        self.foreground_platform.prompt_for_paths(options)
 917    }
 918
 919    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
 920        self.foreground_platform.prompt_for_new_path(directory)
 921    }
 922
 923    pub fn reveal_path(&self, path: &Path) {
 924        self.foreground_platform.reveal_path(path)
 925    }
 926
 927    pub fn emit_global<E: Any>(&mut self, payload: E) {
 928        self.pending_effects.push_back(Effect::GlobalEvent {
 929            payload: Box::new(payload),
 930        });
 931    }
 932
 933    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 934    where
 935        E: Entity,
 936        E::Event: 'static,
 937        H: Handle<E>,
 938        F: 'static + FnMut(H, &E::Event, &mut Self),
 939    {
 940        self.subscribe_internal(handle, move |handle, event, cx| {
 941            callback(handle, event, cx);
 942            true
 943        })
 944    }
 945
 946    pub fn subscribe_global<E, F>(&mut self, mut callback: F) -> Subscription
 947    where
 948        E: Any,
 949        F: 'static + FnMut(&E, &mut Self),
 950    {
 951        let subscription_id = post_inc(&mut self.next_subscription_id);
 952        let type_id = TypeId::of::<E>();
 953        self.pending_effects.push_back(Effect::GlobalSubscription {
 954            type_id,
 955            subscription_id,
 956            callback: Box::new(move |payload, cx| {
 957                let payload = payload.downcast_ref().expect("downcast is type safe");
 958                callback(payload, cx)
 959            }),
 960        });
 961        Subscription::GlobalSubscription(
 962            self.global_subscriptions
 963                .subscribe(type_id, subscription_id),
 964        )
 965    }
 966
 967    pub fn observe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 968    where
 969        E: Entity,
 970        E::Event: 'static,
 971        H: Handle<E>,
 972        F: 'static + FnMut(H, &mut Self),
 973    {
 974        self.observe_internal(handle, move |handle, cx| {
 975            callback(handle, cx);
 976            true
 977        })
 978    }
 979
 980    pub fn subscribe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 981    where
 982        E: Entity,
 983        E::Event: 'static,
 984        H: Handle<E>,
 985        F: 'static + FnMut(H, &E::Event, &mut Self) -> bool,
 986    {
 987        let subscription_id = post_inc(&mut self.next_subscription_id);
 988        let emitter = handle.downgrade();
 989        self.pending_effects.push_back(Effect::Subscription {
 990            entity_id: handle.id(),
 991            subscription_id,
 992            callback: Box::new(move |payload, cx| {
 993                if let Some(emitter) = H::upgrade_from(&emitter, cx) {
 994                    let payload = payload.downcast_ref().expect("downcast is type safe");
 995                    callback(emitter, payload, cx)
 996                } else {
 997                    false
 998                }
 999            }),
1000        });
1001        Subscription::Subscription(self.subscriptions.subscribe(handle.id(), subscription_id))
1002    }
1003
1004    fn observe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
1005    where
1006        E: Entity,
1007        E::Event: 'static,
1008        H: Handle<E>,
1009        F: 'static + FnMut(H, &mut Self) -> bool,
1010    {
1011        let subscription_id = post_inc(&mut self.next_subscription_id);
1012        let observed = handle.downgrade();
1013        let entity_id = handle.id();
1014        self.pending_effects.push_back(Effect::Observation {
1015            entity_id,
1016            subscription_id,
1017            callback: Box::new(move |cx| {
1018                if let Some(observed) = H::upgrade_from(&observed, cx) {
1019                    callback(observed, cx)
1020                } else {
1021                    false
1022                }
1023            }),
1024        });
1025        Subscription::Observation(self.observations.subscribe(entity_id, subscription_id))
1026    }
1027
1028    fn observe_focus<F, V>(&mut self, handle: &ViewHandle<V>, mut callback: F) -> Subscription
1029    where
1030        F: 'static + FnMut(ViewHandle<V>, bool, &mut AppContext) -> bool,
1031        V: View,
1032    {
1033        let subscription_id = post_inc(&mut self.next_subscription_id);
1034        let observed = handle.downgrade();
1035        let view_id = handle.id();
1036
1037        self.pending_effects.push_back(Effect::FocusObservation {
1038            view_id,
1039            subscription_id,
1040            callback: Box::new(move |focused, cx| {
1041                if let Some(observed) = observed.upgrade(cx) {
1042                    callback(observed, focused, cx)
1043                } else {
1044                    false
1045                }
1046            }),
1047        });
1048        Subscription::FocusObservation(self.focus_observations.subscribe(view_id, subscription_id))
1049    }
1050
1051    pub fn observe_global<G, F>(&mut self, mut observe: F) -> Subscription
1052    where
1053        G: Any,
1054        F: 'static + FnMut(&mut AppContext),
1055    {
1056        let type_id = TypeId::of::<G>();
1057        let id = post_inc(&mut self.next_subscription_id);
1058
1059        self.global_observations.add_callback(
1060            type_id,
1061            id,
1062            Box::new(move |cx: &mut AppContext| observe(cx)),
1063        );
1064        Subscription::GlobalObservation(self.global_observations.subscribe(type_id, id))
1065    }
1066
1067    pub fn observe_default_global<G, F>(&mut self, observe: F) -> Subscription
1068    where
1069        G: Any + Default,
1070        F: 'static + FnMut(&mut AppContext),
1071    {
1072        if !self.has_global::<G>() {
1073            self.set_global(G::default());
1074        }
1075        self.observe_global::<G, F>(observe)
1076    }
1077
1078    pub fn observe_release<E, H, F>(&mut self, handle: &H, callback: F) -> Subscription
1079    where
1080        E: Entity,
1081        E::Event: 'static,
1082        H: Handle<E>,
1083        F: 'static + FnOnce(&E, &mut Self),
1084    {
1085        let id = post_inc(&mut self.next_subscription_id);
1086        let mut callback = Some(callback);
1087        self.release_observations.add_callback(
1088            handle.id(),
1089            id,
1090            Box::new(move |released, cx| {
1091                let released = released.downcast_ref().unwrap();
1092                if let Some(callback) = callback.take() {
1093                    callback(released, cx)
1094                }
1095            }),
1096        );
1097        Subscription::ReleaseObservation(self.release_observations.subscribe(handle.id(), id))
1098    }
1099
1100    pub fn observe_actions<F>(&mut self, callback: F) -> Subscription
1101    where
1102        F: 'static + FnMut(TypeId, &mut AppContext),
1103    {
1104        let subscription_id = post_inc(&mut self.next_subscription_id);
1105        self.action_dispatch_observations
1106            .add_callback((), subscription_id, Box::new(callback));
1107        Subscription::ActionObservation(
1108            self.action_dispatch_observations
1109                .subscribe((), subscription_id),
1110        )
1111    }
1112
1113    fn observe_window_activation<F>(&mut self, window_id: usize, callback: F) -> Subscription
1114    where
1115        F: 'static + FnMut(bool, &mut AppContext) -> bool,
1116    {
1117        let subscription_id = post_inc(&mut self.next_subscription_id);
1118        self.pending_effects
1119            .push_back(Effect::WindowActivationObservation {
1120                window_id,
1121                subscription_id,
1122                callback: Box::new(callback),
1123            });
1124        Subscription::WindowActivationObservation(
1125            self.window_activation_observations
1126                .subscribe(window_id, subscription_id),
1127        )
1128    }
1129
1130    fn observe_fullscreen<F>(&mut self, window_id: usize, callback: F) -> Subscription
1131    where
1132        F: 'static + FnMut(bool, &mut AppContext) -> bool,
1133    {
1134        let subscription_id = post_inc(&mut self.next_subscription_id);
1135        self.pending_effects
1136            .push_back(Effect::WindowFullscreenObservation {
1137                window_id,
1138                subscription_id,
1139                callback: Box::new(callback),
1140            });
1141        Subscription::WindowActivationObservation(
1142            self.window_activation_observations
1143                .subscribe(window_id, subscription_id),
1144        )
1145    }
1146
1147    fn observe_window_bounds<F>(&mut self, window_id: usize, callback: F) -> Subscription
1148    where
1149        F: 'static + FnMut(WindowBounds, Uuid, &mut AppContext) -> bool,
1150    {
1151        let subscription_id = post_inc(&mut self.next_subscription_id);
1152        self.pending_effects
1153            .push_back(Effect::WindowBoundsObservation {
1154                window_id,
1155                subscription_id,
1156                callback: Box::new(callback),
1157            });
1158        Subscription::WindowBoundsObservation(
1159            self.window_bounds_observations
1160                .subscribe(window_id, subscription_id),
1161        )
1162    }
1163
1164    pub fn observe_keystrokes<F>(&mut self, window_id: usize, callback: F) -> Subscription
1165    where
1166        F: 'static
1167            + FnMut(&Keystroke, &MatchResult, Option<&Box<dyn Action>>, &mut AppContext) -> bool,
1168    {
1169        let subscription_id = post_inc(&mut self.next_subscription_id);
1170        self.keystroke_observations
1171            .add_callback(window_id, subscription_id, Box::new(callback));
1172        Subscription::KeystrokeObservation(
1173            self.keystroke_observations
1174                .subscribe(window_id, subscription_id),
1175        )
1176    }
1177
1178    pub fn observe_active_labeled_tasks<F>(&mut self, callback: F) -> Subscription
1179    where
1180        F: 'static + FnMut(&mut AppContext) -> bool,
1181    {
1182        let subscription_id = post_inc(&mut self.next_subscription_id);
1183        self.active_labeled_task_observations
1184            .add_callback((), subscription_id, Box::new(callback));
1185        Subscription::ActiveLabeledTasksObservation(
1186            self.active_labeled_task_observations
1187                .subscribe((), subscription_id),
1188        )
1189    }
1190
1191    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut AppContext)) {
1192        self.pending_effects.push_back(Effect::Deferred {
1193            callback: Box::new(callback),
1194            after_window_update: false,
1195        })
1196    }
1197
1198    pub fn after_window_update(&mut self, callback: impl 'static + FnOnce(&mut AppContext)) {
1199        self.pending_effects.push_back(Effect::Deferred {
1200            callback: Box::new(callback),
1201            after_window_update: true,
1202        })
1203    }
1204
1205    pub(crate) fn notify_model(&mut self, model_id: usize) {
1206        if self.pending_notifications.insert(model_id) {
1207            self.pending_effects
1208                .push_back(Effect::ModelNotification { model_id });
1209        }
1210    }
1211
1212    pub(crate) fn notify_view(&mut self, window_id: usize, view_id: usize) {
1213        if self.pending_notifications.insert(view_id) {
1214            self.pending_effects
1215                .push_back(Effect::ViewNotification { window_id, view_id });
1216        }
1217    }
1218
1219    pub(crate) fn notify_global(&mut self, type_id: TypeId) {
1220        if self.pending_global_notifications.insert(type_id) {
1221            self.pending_effects
1222                .push_back(Effect::GlobalNotification { type_id });
1223        }
1224    }
1225
1226    pub(crate) fn name_for_view(&self, window_id: usize, view_id: usize) -> Option<&str> {
1227        self.views
1228            .get(&(window_id, view_id))
1229            .map(|view| view.ui_name())
1230    }
1231
1232    pub fn all_action_names<'a>(&'a self) -> impl Iterator<Item = &'static str> + 'a {
1233        self.action_deserializers.keys().copied()
1234    }
1235
1236    /// Return keystrokes that would dispatch the given action on the given view.
1237    pub(crate) fn keystrokes_for_action(
1238        &mut self,
1239        window_id: usize,
1240        view_id: usize,
1241        action: &dyn Action,
1242    ) -> Option<SmallVec<[Keystroke; 2]>> {
1243        let mut contexts = Vec::new();
1244        let mut handler_depth = None;
1245        for (i, view_id) in self.ancestors(window_id, view_id).enumerate() {
1246            if let Some(view) = self.views.get(&(window_id, view_id)) {
1247                if let Some(actions) = self.actions.get(&view.as_any().type_id()) {
1248                    if actions.contains_key(&action.as_any().type_id()) {
1249                        handler_depth = Some(i);
1250                    }
1251                }
1252                contexts.push(view.keymap_context(self));
1253            }
1254        }
1255
1256        if self.global_actions.contains_key(&action.as_any().type_id()) {
1257            handler_depth = Some(contexts.len())
1258        }
1259
1260        self.keystroke_matcher
1261            .bindings_for_action_type(action.as_any().type_id())
1262            .find_map(|b| {
1263                handler_depth
1264                    .map(|highest_handler| {
1265                        if (0..=highest_handler).any(|depth| b.match_context(&contexts[depth..])) {
1266                            Some(b.keystrokes().into())
1267                        } else {
1268                            None
1269                        }
1270                    })
1271                    .flatten()
1272            })
1273    }
1274
1275    pub fn available_actions(
1276        &self,
1277        window_id: usize,
1278        view_id: usize,
1279    ) -> impl Iterator<Item = (&'static str, Box<dyn Action>, SmallVec<[&Binding; 1]>)> {
1280        let mut contexts = Vec::new();
1281        let mut handler_depths_by_action_type = HashMap::<TypeId, usize>::default();
1282        for (depth, view_id) in self.ancestors(window_id, view_id).enumerate() {
1283            if let Some(view) = self.views.get(&(window_id, view_id)) {
1284                contexts.push(view.keymap_context(self));
1285                let view_type = view.as_any().type_id();
1286                if let Some(actions) = self.actions.get(&view_type) {
1287                    handler_depths_by_action_type.extend(
1288                        actions
1289                            .keys()
1290                            .copied()
1291                            .map(|action_type| (action_type, depth)),
1292                    );
1293                }
1294            }
1295        }
1296
1297        handler_depths_by_action_type.extend(
1298            self.global_actions
1299                .keys()
1300                .copied()
1301                .map(|action_type| (action_type, contexts.len())),
1302        );
1303
1304        self.action_deserializers
1305            .iter()
1306            .filter_map(move |(name, (type_id, deserialize))| {
1307                if let Some(action_depth) = handler_depths_by_action_type.get(type_id).copied() {
1308                    Some((
1309                        *name,
1310                        deserialize("{}").ok()?,
1311                        self.keystroke_matcher
1312                            .bindings_for_action_type(*type_id)
1313                            .filter(|b| {
1314                                (0..=action_depth).any(|depth| b.match_context(&contexts[depth..]))
1315                            })
1316                            .collect(),
1317                    ))
1318                } else {
1319                    None
1320                }
1321            })
1322    }
1323
1324    pub fn is_action_available(&self, action: &dyn Action) -> bool {
1325        let action_type = action.as_any().type_id();
1326        if let Some(window_id) = self.platform.main_window_id() {
1327            if let Some(focused_view_id) = self.focused_view_id(window_id) {
1328                for view_id in self.ancestors(window_id, focused_view_id) {
1329                    if let Some(view) = self.views.get(&(window_id, view_id)) {
1330                        let view_type = view.as_any().type_id();
1331                        if let Some(actions) = self.actions.get(&view_type) {
1332                            if actions.contains_key(&action_type) {
1333                                return true;
1334                            }
1335                        }
1336                    }
1337                }
1338            }
1339        }
1340        self.global_actions.contains_key(&action_type)
1341    }
1342
1343    // Traverses the parent tree. Walks down the tree toward the passed
1344    // view calling visit with true. Then walks back up the tree calling visit with false.
1345    // If `visit` returns false this function will immediately return.
1346    // Returns a bool indicating if the traversal was completed early.
1347    fn visit_dispatch_path(
1348        &mut self,
1349        window_id: usize,
1350        view_id: usize,
1351        mut visit: impl FnMut(usize, bool, &mut AppContext) -> bool,
1352    ) -> bool {
1353        // List of view ids from the leaf to the root of the window
1354        let path = self.ancestors(window_id, view_id).collect::<Vec<_>>();
1355
1356        // Walk down from the root to the leaf calling visit with capture_phase = true
1357        for view_id in path.iter().rev() {
1358            if !visit(*view_id, true, self) {
1359                return false;
1360            }
1361        }
1362
1363        // Walk up from the leaf to the root calling visit with capture_phase = false
1364        for view_id in path.iter() {
1365            if !visit(*view_id, false, self) {
1366                return false;
1367            }
1368        }
1369
1370        true
1371    }
1372
1373    fn actions_mut(
1374        &mut self,
1375        capture_phase: bool,
1376    ) -> &mut HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>> {
1377        if capture_phase {
1378            &mut self.capture_actions
1379        } else {
1380            &mut self.actions
1381        }
1382    }
1383
1384    pub fn dispatch_global_action<A: Action>(&mut self, action: A) {
1385        self.dispatch_global_action_any(&action);
1386    }
1387
1388    fn dispatch_global_action_any(&mut self, action: &dyn Action) -> bool {
1389        self.update(|this| {
1390            if let Some((name, mut handler)) = this.global_actions.remove_entry(&action.id()) {
1391                handler(action, this);
1392                this.global_actions.insert(name, handler);
1393                true
1394            } else {
1395                false
1396            }
1397        })
1398    }
1399
1400    pub fn add_bindings<T: IntoIterator<Item = Binding>>(&mut self, bindings: T) {
1401        self.keystroke_matcher.add_bindings(bindings);
1402    }
1403
1404    pub fn clear_bindings(&mut self) {
1405        self.keystroke_matcher.clear_bindings();
1406    }
1407
1408    pub fn dispatch_key_down(&mut self, window_id: usize, event: &KeyDownEvent) -> bool {
1409        if let Some(focused_view_id) = self.focused_view_id(window_id) {
1410            for view_id in self
1411                .ancestors(window_id, focused_view_id)
1412                .collect::<Vec<_>>()
1413            {
1414                if let Some(mut view) = self.views.remove(&(window_id, view_id)) {
1415                    let handled = view.key_down(event, self, window_id, view_id);
1416                    self.views.insert((window_id, view_id), view);
1417                    if handled {
1418                        return true;
1419                    }
1420                } else {
1421                    log::error!("view {} does not exist", view_id)
1422                }
1423            }
1424        }
1425
1426        false
1427    }
1428
1429    pub fn dispatch_key_up(&mut self, window_id: usize, event: &KeyUpEvent) -> bool {
1430        if let Some(focused_view_id) = self.focused_view_id(window_id) {
1431            for view_id in self
1432                .ancestors(window_id, focused_view_id)
1433                .collect::<Vec<_>>()
1434            {
1435                if let Some(mut view) = self.views.remove(&(window_id, view_id)) {
1436                    let handled = view.key_up(event, self, window_id, view_id);
1437                    self.views.insert((window_id, view_id), view);
1438                    if handled {
1439                        return true;
1440                    }
1441                } else {
1442                    log::error!("view {} does not exist", view_id)
1443                }
1444            }
1445        }
1446
1447        false
1448    }
1449
1450    pub fn dispatch_modifiers_changed(
1451        &mut self,
1452        window_id: usize,
1453        event: &ModifiersChangedEvent,
1454    ) -> bool {
1455        if let Some(focused_view_id) = self.focused_view_id(window_id) {
1456            for view_id in self
1457                .ancestors(window_id, focused_view_id)
1458                .collect::<Vec<_>>()
1459            {
1460                if let Some(mut view) = self.views.remove(&(window_id, view_id)) {
1461                    let handled = view.modifiers_changed(event, self, window_id, view_id);
1462                    self.views.insert((window_id, view_id), view);
1463                    if handled {
1464                        return true;
1465                    }
1466                } else {
1467                    log::error!("view {} does not exist", view_id)
1468                }
1469            }
1470        }
1471
1472        false
1473    }
1474
1475    pub fn dispatch_keystroke(&mut self, window_id: usize, keystroke: &Keystroke) -> bool {
1476        if let Some(focused_view_id) = self.focused_view_id(window_id) {
1477            let dispatch_path = self
1478                .ancestors(window_id, focused_view_id)
1479                .filter_map(|view_id| {
1480                    self.views
1481                        .get(&(window_id, view_id))
1482                        .map(|view| (view_id, view.keymap_context(self)))
1483                })
1484                .collect();
1485
1486            let match_result = self
1487                .keystroke_matcher
1488                .push_keystroke(keystroke.clone(), dispatch_path);
1489            let mut handled_by = None;
1490
1491            let keystroke_handled = match &match_result {
1492                MatchResult::None => false,
1493                MatchResult::Pending => true,
1494                MatchResult::Matches(matches) => {
1495                    for (view_id, action) in matches {
1496                        if self.handle_dispatch_action_from_effect(
1497                            window_id,
1498                            Some(*view_id),
1499                            action.as_ref(),
1500                        ) {
1501                            self.keystroke_matcher.clear_pending();
1502                            handled_by = Some(action.boxed_clone());
1503                            break;
1504                        }
1505                    }
1506                    handled_by.is_some()
1507                }
1508            };
1509
1510            self.keystroke(
1511                window_id,
1512                keystroke.clone(),
1513                handled_by,
1514                match_result.clone(),
1515            );
1516            keystroke_handled
1517        } else {
1518            self.keystroke(window_id, keystroke.clone(), None, MatchResult::None);
1519            false
1520        }
1521    }
1522
1523    pub fn default_global<T: 'static + Default>(&mut self) -> &T {
1524        let type_id = TypeId::of::<T>();
1525        self.update(|this| {
1526            if let Entry::Vacant(entry) = this.globals.entry(type_id) {
1527                entry.insert(Box::new(T::default()));
1528                this.notify_global(type_id);
1529            }
1530        });
1531        self.globals.get(&type_id).unwrap().downcast_ref().unwrap()
1532    }
1533
1534    pub fn set_global<T: 'static>(&mut self, state: T) {
1535        self.update(|this| {
1536            let type_id = TypeId::of::<T>();
1537            this.globals.insert(type_id, Box::new(state));
1538            this.notify_global(type_id);
1539        });
1540    }
1541
1542    pub fn update_default_global<T, F, U>(&mut self, update: F) -> U
1543    where
1544        T: 'static + Default,
1545        F: FnOnce(&mut T, &mut AppContext) -> U,
1546    {
1547        self.update(|this| {
1548            let type_id = TypeId::of::<T>();
1549            let mut state = this
1550                .globals
1551                .remove(&type_id)
1552                .unwrap_or_else(|| Box::new(T::default()));
1553            let result = update(state.downcast_mut().unwrap(), this);
1554            this.globals.insert(type_id, state);
1555            this.notify_global(type_id);
1556            result
1557        })
1558    }
1559
1560    pub fn update_global<T, F, U>(&mut self, update: F) -> U
1561    where
1562        T: 'static,
1563        F: FnOnce(&mut T, &mut AppContext) -> U,
1564    {
1565        self.update(|this| {
1566            let type_id = TypeId::of::<T>();
1567            if let Some(mut state) = this.globals.remove(&type_id) {
1568                let result = update(state.downcast_mut().unwrap(), this);
1569                this.globals.insert(type_id, state);
1570                this.notify_global(type_id);
1571                result
1572            } else {
1573                panic!("No global added for {}", std::any::type_name::<T>());
1574            }
1575        })
1576    }
1577
1578    pub fn clear_globals(&mut self) {
1579        self.globals.clear();
1580    }
1581
1582    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
1583    where
1584        T: Entity,
1585        F: FnOnce(&mut ModelContext<T>) -> T,
1586    {
1587        self.update(|this| {
1588            let model_id = post_inc(&mut this.next_entity_id);
1589            let handle = ModelHandle::new(model_id, &this.ref_counts);
1590            let mut cx = ModelContext::new(this, model_id);
1591            let model = build_model(&mut cx);
1592            this.models.insert(model_id, Box::new(model));
1593            handle
1594        })
1595    }
1596
1597    pub fn add_window<T, F>(
1598        &mut self,
1599        window_options: WindowOptions,
1600        build_root_view: F,
1601    ) -> (usize, ViewHandle<T>)
1602    where
1603        T: View,
1604        F: FnOnce(&mut ViewContext<T>) -> T,
1605    {
1606        self.update(|this| {
1607            let window_id = post_inc(&mut this.next_window_id);
1608            let root_view = this
1609                .build_and_insert_view(window_id, ParentId::Root, |cx| Some(build_root_view(cx)))
1610                .unwrap();
1611            this.windows.insert(
1612                window_id,
1613                Window {
1614                    root_view: root_view.clone().into_any(),
1615                    focused_view_id: Some(root_view.id()),
1616                    is_active: false,
1617                    invalidation: None,
1618                    is_fullscreen: false,
1619                },
1620            );
1621            root_view.update(this, |view, cx| view.focus_in(cx.handle().into_any(), cx));
1622
1623            let window =
1624                this.platform
1625                    .open_window(window_id, window_options, this.foreground.clone());
1626            this.register_platform_window(window_id, window);
1627
1628            (window_id, root_view)
1629        })
1630    }
1631
1632    pub fn add_status_bar_item<T, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<T>)
1633    where
1634        T: View,
1635        F: FnOnce(&mut ViewContext<T>) -> T,
1636    {
1637        self.update(|this| {
1638            let window_id = post_inc(&mut this.next_window_id);
1639            let root_view = this
1640                .build_and_insert_view(window_id, ParentId::Root, |cx| Some(build_root_view(cx)))
1641                .unwrap();
1642            let focused_view_id = root_view.id();
1643            this.windows.insert(
1644                window_id,
1645                Window {
1646                    root_view: root_view.clone().into_any(),
1647                    focused_view_id: Some(focused_view_id),
1648                    is_active: false,
1649                    invalidation: None,
1650                    is_fullscreen: false,
1651                },
1652            );
1653            root_view.update(this, |view, cx| view.focus_in(cx.handle().into_any(), cx));
1654
1655            let status_item = this.platform.add_status_item();
1656            this.register_platform_window(window_id, status_item);
1657
1658            (window_id, root_view)
1659        })
1660    }
1661
1662    pub fn remove_status_bar_item(&mut self, id: usize) {
1663        self.remove_window(id);
1664    }
1665
1666    fn register_platform_window(
1667        &mut self,
1668        window_id: usize,
1669        mut window: Box<dyn platform::Window>,
1670    ) {
1671        let presenter = Rc::new(RefCell::new(self.build_presenter(
1672            window_id,
1673            window.titlebar_height(),
1674            window.appearance(),
1675        )));
1676
1677        {
1678            let mut app = self.upgrade();
1679            let presenter = Rc::downgrade(&presenter);
1680
1681            window.on_event(Box::new(move |event| {
1682                app.update(|cx| {
1683                    if let Some(presenter) = presenter.upgrade() {
1684                        if let Event::KeyDown(KeyDownEvent { keystroke, .. }) = &event {
1685                            if cx.dispatch_keystroke(window_id, keystroke) {
1686                                return true;
1687                            }
1688                        }
1689
1690                        presenter.borrow_mut().dispatch_event(event, false, cx)
1691                    } else {
1692                        false
1693                    }
1694                })
1695            }));
1696        }
1697
1698        {
1699            let mut app = self.upgrade();
1700            window.on_active_status_change(Box::new(move |is_active| {
1701                app.update(|cx| cx.window_changed_active_status(window_id, is_active))
1702            }));
1703        }
1704
1705        {
1706            let mut app = self.upgrade();
1707            window.on_resize(Box::new(move || {
1708                app.update(|cx| cx.window_was_resized(window_id))
1709            }));
1710        }
1711
1712        {
1713            let mut app = self.upgrade();
1714            window.on_moved(Box::new(move || {
1715                app.update(|cx| cx.window_was_moved(window_id))
1716            }));
1717        }
1718
1719        {
1720            let mut app = self.upgrade();
1721            window.on_fullscreen(Box::new(move |is_fullscreen| {
1722                app.update(|cx| cx.window_was_fullscreen_changed(window_id, is_fullscreen))
1723            }));
1724        }
1725
1726        {
1727            let mut app = self.upgrade();
1728            window.on_close(Box::new(move || {
1729                app.update(|cx| cx.remove_window(window_id));
1730            }));
1731        }
1732
1733        {
1734            let mut app = self.upgrade();
1735            window.on_appearance_changed(Box::new(move || app.update(|cx| cx.refresh_windows())));
1736        }
1737
1738        window.set_input_handler(Box::new(WindowInputHandler {
1739            app: self.upgrade().0,
1740            window_id,
1741        }));
1742
1743        let scene = presenter.borrow_mut().build_scene(
1744            window.content_size(),
1745            window.scale_factor(),
1746            false,
1747            self,
1748        );
1749        window.present_scene(scene);
1750        self.presenters_and_platform_windows
1751            .insert(window_id, (presenter.clone(), window));
1752    }
1753
1754    pub fn replace_root_view<T, F>(&mut self, window_id: usize, build_root_view: F) -> ViewHandle<T>
1755    where
1756        T: View,
1757        F: FnOnce(&mut ViewContext<T>) -> T,
1758    {
1759        self.update(|this| {
1760            let root_view = this
1761                .build_and_insert_view(window_id, ParentId::Root, |cx| Some(build_root_view(cx)))
1762                .unwrap();
1763            let window = this.windows.get_mut(&window_id).unwrap();
1764            window.root_view = root_view.clone().into_any();
1765            window.focused_view_id = Some(root_view.id());
1766            root_view
1767        })
1768    }
1769
1770    pub fn remove_window(&mut self, window_id: usize) {
1771        self.windows.remove(&window_id);
1772        self.presenters_and_platform_windows.remove(&window_id);
1773        self.flush_effects();
1774    }
1775
1776    pub fn build_presenter(
1777        &mut self,
1778        window_id: usize,
1779        titlebar_height: f32,
1780        appearance: Appearance,
1781    ) -> Presenter {
1782        Presenter::new(
1783            window_id,
1784            titlebar_height,
1785            appearance,
1786            self.font_cache.clone(),
1787            TextLayoutCache::new(self.platform.fonts()),
1788            self.assets.clone(),
1789            self,
1790        )
1791    }
1792
1793    pub fn add_view<T, F>(&mut self, parent_handle: &AnyViewHandle, build_view: F) -> ViewHandle<T>
1794    where
1795        T: View,
1796        F: FnOnce(&mut ViewContext<T>) -> T,
1797    {
1798        self.build_and_insert_view(
1799            parent_handle.window_id,
1800            ParentId::View(parent_handle.view_id),
1801            |cx| Some(build_view(cx)),
1802        )
1803        .unwrap()
1804    }
1805
1806    pub fn add_option_view<T, F>(
1807        &mut self,
1808        parent_handle: impl Into<AnyViewHandle>,
1809        build_view: F,
1810    ) -> Option<ViewHandle<T>>
1811    where
1812        T: View,
1813        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
1814    {
1815        let parent_handle = parent_handle.into();
1816        self.build_and_insert_view(
1817            parent_handle.window_id,
1818            ParentId::View(parent_handle.view_id),
1819            build_view,
1820        )
1821    }
1822
1823    pub(crate) fn build_and_insert_view<T, F>(
1824        &mut self,
1825        window_id: usize,
1826        parent_id: ParentId,
1827        build_view: F,
1828    ) -> Option<ViewHandle<T>>
1829    where
1830        T: View,
1831        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
1832    {
1833        self.update(|this| {
1834            let view_id = post_inc(&mut this.next_entity_id);
1835            // Make sure we can tell child views about their parent
1836            this.parents.insert((window_id, view_id), parent_id);
1837            let mut cx = ViewContext::new(this, window_id, view_id);
1838            let handle = if let Some(view) = build_view(&mut cx) {
1839                this.views.insert((window_id, view_id), Box::new(view));
1840                if let Some(window) = this.windows.get_mut(&window_id) {
1841                    window
1842                        .invalidation
1843                        .get_or_insert_with(Default::default)
1844                        .updated
1845                        .insert(view_id);
1846                }
1847                Some(ViewHandle::new(window_id, view_id, &this.ref_counts))
1848            } else {
1849                this.parents.remove(&(window_id, view_id));
1850                None
1851            };
1852            handle
1853        })
1854    }
1855
1856    fn remove_dropped_entities(&mut self) {
1857        loop {
1858            let (dropped_models, dropped_views, dropped_element_states) =
1859                self.ref_counts.lock().take_dropped();
1860            if dropped_models.is_empty()
1861                && dropped_views.is_empty()
1862                && dropped_element_states.is_empty()
1863            {
1864                break;
1865            }
1866
1867            for model_id in dropped_models {
1868                self.subscriptions.remove(model_id);
1869                self.observations.remove(model_id);
1870                let mut model = self.models.remove(&model_id).unwrap();
1871                model.release(self);
1872                self.pending_effects
1873                    .push_back(Effect::ModelRelease { model_id, model });
1874            }
1875
1876            for (window_id, view_id) in dropped_views {
1877                self.subscriptions.remove(view_id);
1878                self.observations.remove(view_id);
1879                let mut view = self.views.remove(&(window_id, view_id)).unwrap();
1880                view.release(self);
1881                let change_focus_to = self.windows.get_mut(&window_id).and_then(|window| {
1882                    window
1883                        .invalidation
1884                        .get_or_insert_with(Default::default)
1885                        .removed
1886                        .push(view_id);
1887                    if window.focused_view_id == Some(view_id) {
1888                        Some(window.root_view.id())
1889                    } else {
1890                        None
1891                    }
1892                });
1893                self.parents.remove(&(window_id, view_id));
1894
1895                if let Some(view_id) = change_focus_to {
1896                    self.handle_focus_effect(window_id, Some(view_id));
1897                }
1898
1899                self.pending_effects
1900                    .push_back(Effect::ViewRelease { view_id, view });
1901            }
1902
1903            for key in dropped_element_states {
1904                self.element_states.remove(&key);
1905            }
1906        }
1907    }
1908
1909    fn flush_effects(&mut self) {
1910        self.pending_flushes = self.pending_flushes.saturating_sub(1);
1911        let mut after_window_update_callbacks = Vec::new();
1912
1913        if !self.flushing_effects && self.pending_flushes == 0 {
1914            self.flushing_effects = true;
1915
1916            let mut refreshing = false;
1917            loop {
1918                if let Some(effect) = self.pending_effects.pop_front() {
1919                    match effect {
1920                        Effect::Subscription {
1921                            entity_id,
1922                            subscription_id,
1923                            callback,
1924                        } => self
1925                            .subscriptions
1926                            .add_callback(entity_id, subscription_id, callback),
1927
1928                        Effect::Event { entity_id, payload } => {
1929                            let mut subscriptions = self.subscriptions.clone();
1930                            subscriptions.emit(entity_id, self, |callback, this| {
1931                                callback(payload.as_ref(), this)
1932                            })
1933                        }
1934
1935                        Effect::GlobalSubscription {
1936                            type_id,
1937                            subscription_id,
1938                            callback,
1939                        } => self.global_subscriptions.add_callback(
1940                            type_id,
1941                            subscription_id,
1942                            callback,
1943                        ),
1944
1945                        Effect::GlobalEvent { payload } => self.emit_global_event(payload),
1946
1947                        Effect::Observation {
1948                            entity_id,
1949                            subscription_id,
1950                            callback,
1951                        } => self
1952                            .observations
1953                            .add_callback(entity_id, subscription_id, callback),
1954
1955                        Effect::ModelNotification { model_id } => {
1956                            let mut observations = self.observations.clone();
1957                            observations.emit(model_id, self, |callback, this| callback(this));
1958                        }
1959
1960                        Effect::ViewNotification { window_id, view_id } => {
1961                            self.handle_view_notification_effect(window_id, view_id)
1962                        }
1963
1964                        Effect::GlobalNotification { type_id } => {
1965                            let mut subscriptions = self.global_observations.clone();
1966                            subscriptions.emit(type_id, self, |callback, this| {
1967                                callback(this);
1968                                true
1969                            });
1970                        }
1971
1972                        Effect::Deferred {
1973                            callback,
1974                            after_window_update,
1975                        } => {
1976                            if after_window_update {
1977                                after_window_update_callbacks.push(callback);
1978                            } else {
1979                                callback(self)
1980                            }
1981                        }
1982
1983                        Effect::ModelRelease { model_id, model } => {
1984                            self.handle_entity_release_effect(model_id, model.as_any())
1985                        }
1986
1987                        Effect::ViewRelease { view_id, view } => {
1988                            self.handle_entity_release_effect(view_id, view.as_any())
1989                        }
1990
1991                        Effect::Focus { window_id, view_id } => {
1992                            self.handle_focus_effect(window_id, view_id);
1993                        }
1994
1995                        Effect::FocusObservation {
1996                            view_id,
1997                            subscription_id,
1998                            callback,
1999                        } => {
2000                            self.focus_observations.add_callback(
2001                                view_id,
2002                                subscription_id,
2003                                callback,
2004                            );
2005                        }
2006
2007                        Effect::ResizeWindow { window_id } => {
2008                            if let Some(window) = self.windows.get_mut(&window_id) {
2009                                window
2010                                    .invalidation
2011                                    .get_or_insert(WindowInvalidation::default());
2012                            }
2013                            self.handle_window_moved(window_id);
2014                        }
2015
2016                        Effect::MoveWindow { window_id } => {
2017                            self.handle_window_moved(window_id);
2018                        }
2019
2020                        Effect::WindowActivationObservation {
2021                            window_id,
2022                            subscription_id,
2023                            callback,
2024                        } => self.window_activation_observations.add_callback(
2025                            window_id,
2026                            subscription_id,
2027                            callback,
2028                        ),
2029
2030                        Effect::ActivateWindow {
2031                            window_id,
2032                            is_active,
2033                        } => self.handle_window_activation_effect(window_id, is_active),
2034
2035                        Effect::WindowFullscreenObservation {
2036                            window_id,
2037                            subscription_id,
2038                            callback,
2039                        } => self.window_fullscreen_observations.add_callback(
2040                            window_id,
2041                            subscription_id,
2042                            callback,
2043                        ),
2044
2045                        Effect::FullscreenWindow {
2046                            window_id,
2047                            is_fullscreen,
2048                        } => self.handle_fullscreen_effect(window_id, is_fullscreen),
2049
2050                        Effect::WindowBoundsObservation {
2051                            window_id,
2052                            subscription_id,
2053                            callback,
2054                        } => self.window_bounds_observations.add_callback(
2055                            window_id,
2056                            subscription_id,
2057                            callback,
2058                        ),
2059
2060                        Effect::RefreshWindows => {
2061                            refreshing = true;
2062                        }
2063                        Effect::DispatchActionFrom {
2064                            window_id,
2065                            view_id,
2066                            action,
2067                        } => {
2068                            self.handle_dispatch_action_from_effect(
2069                                window_id,
2070                                Some(view_id),
2071                                action.as_ref(),
2072                            );
2073                        }
2074                        Effect::ActionDispatchNotification { action_id } => {
2075                            self.handle_action_dispatch_notification_effect(action_id)
2076                        }
2077                        Effect::WindowShouldCloseSubscription {
2078                            window_id,
2079                            callback,
2080                        } => {
2081                            self.handle_window_should_close_subscription_effect(window_id, callback)
2082                        }
2083                        Effect::Keystroke {
2084                            window_id,
2085                            keystroke,
2086                            handled_by,
2087                            result,
2088                        } => self.handle_keystroke_effect(window_id, keystroke, handled_by, result),
2089                        Effect::ActiveLabeledTasksChanged => {
2090                            self.handle_active_labeled_tasks_changed_effect()
2091                        }
2092                        Effect::ActiveLabeledTasksObservation {
2093                            subscription_id,
2094                            callback,
2095                        } => self.active_labeled_task_observations.add_callback(
2096                            (),
2097                            subscription_id,
2098                            callback,
2099                        ),
2100                    }
2101                    self.pending_notifications.clear();
2102                    self.remove_dropped_entities();
2103                } else {
2104                    self.remove_dropped_entities();
2105
2106                    if refreshing {
2107                        self.perform_window_refresh();
2108                    } else {
2109                        self.update_windows();
2110                    }
2111
2112                    if self.pending_effects.is_empty() {
2113                        for callback in after_window_update_callbacks.drain(..) {
2114                            callback(self);
2115                        }
2116
2117                        if self.pending_effects.is_empty() {
2118                            self.flushing_effects = false;
2119                            self.pending_notifications.clear();
2120                            self.pending_global_notifications.clear();
2121                            break;
2122                        }
2123                    }
2124
2125                    refreshing = false;
2126                }
2127            }
2128        }
2129    }
2130
2131    fn update_windows(&mut self) {
2132        let mut invalidations: HashMap<_, _> = Default::default();
2133        for (window_id, window) in &mut self.windows {
2134            if let Some(invalidation) = window.invalidation.take() {
2135                invalidations.insert(*window_id, invalidation);
2136            }
2137        }
2138
2139        for (window_id, mut invalidation) in invalidations {
2140            if let Some((presenter, mut window)) =
2141                self.presenters_and_platform_windows.remove(&window_id)
2142            {
2143                {
2144                    let mut presenter = presenter.borrow_mut();
2145                    presenter.invalidate(&mut invalidation, window.appearance(), self);
2146                    let scene = presenter.build_scene(
2147                        window.content_size(),
2148                        window.scale_factor(),
2149                        false,
2150                        self,
2151                    );
2152                    window.present_scene(scene);
2153                }
2154                self.presenters_and_platform_windows
2155                    .insert(window_id, (presenter, window));
2156            }
2157        }
2158    }
2159
2160    fn window_was_resized(&mut self, window_id: usize) {
2161        self.pending_effects
2162            .push_back(Effect::ResizeWindow { window_id });
2163    }
2164
2165    fn window_was_moved(&mut self, window_id: usize) {
2166        self.pending_effects
2167            .push_back(Effect::MoveWindow { window_id });
2168    }
2169
2170    fn window_was_fullscreen_changed(&mut self, window_id: usize, is_fullscreen: bool) {
2171        self.pending_effects.push_back(Effect::FullscreenWindow {
2172            window_id,
2173            is_fullscreen,
2174        });
2175    }
2176
2177    fn window_changed_active_status(&mut self, window_id: usize, is_active: bool) {
2178        self.pending_effects.push_back(Effect::ActivateWindow {
2179            window_id,
2180            is_active,
2181        });
2182    }
2183
2184    fn keystroke(
2185        &mut self,
2186        window_id: usize,
2187        keystroke: Keystroke,
2188        handled_by: Option<Box<dyn Action>>,
2189        result: MatchResult,
2190    ) {
2191        self.pending_effects.push_back(Effect::Keystroke {
2192            window_id,
2193            keystroke,
2194            handled_by,
2195            result,
2196        });
2197    }
2198
2199    pub fn refresh_windows(&mut self) {
2200        self.pending_effects.push_back(Effect::RefreshWindows);
2201    }
2202
2203    pub fn dispatch_action_at(&mut self, window_id: usize, view_id: usize, action: impl Action) {
2204        self.dispatch_any_action_at(window_id, view_id, Box::new(action));
2205    }
2206
2207    pub fn dispatch_any_action_at(
2208        &mut self,
2209        window_id: usize,
2210        view_id: usize,
2211        action: Box<dyn Action>,
2212    ) {
2213        self.pending_effects.push_back(Effect::DispatchActionFrom {
2214            window_id,
2215            view_id,
2216            action,
2217        });
2218    }
2219
2220    fn perform_window_refresh(&mut self) {
2221        let mut presenters = mem::take(&mut self.presenters_and_platform_windows);
2222        for (window_id, (presenter, window)) in &mut presenters {
2223            let mut invalidation = self.windows.get_mut(window_id).unwrap().invalidation.take();
2224            let mut presenter = presenter.borrow_mut();
2225            presenter.refresh(
2226                invalidation.as_mut().unwrap_or(&mut Default::default()),
2227                window.appearance(),
2228                self,
2229            );
2230            let scene =
2231                presenter.build_scene(window.content_size(), window.scale_factor(), true, self);
2232            window.present_scene(scene);
2233        }
2234        self.presenters_and_platform_windows = presenters;
2235    }
2236
2237    fn emit_global_event(&mut self, payload: Box<dyn Any>) {
2238        let type_id = (&*payload).type_id();
2239
2240        let mut subscriptions = self.global_subscriptions.clone();
2241        subscriptions.emit(type_id, self, |callback, this| {
2242            callback(payload.as_ref(), this);
2243            true //Always alive
2244        });
2245    }
2246
2247    fn handle_view_notification_effect(
2248        &mut self,
2249        observed_window_id: usize,
2250        observed_view_id: usize,
2251    ) {
2252        if self
2253            .views
2254            .contains_key(&(observed_window_id, observed_view_id))
2255        {
2256            if let Some(window) = self.windows.get_mut(&observed_window_id) {
2257                window
2258                    .invalidation
2259                    .get_or_insert_with(Default::default)
2260                    .updated
2261                    .insert(observed_view_id);
2262            }
2263
2264            let mut observations = self.observations.clone();
2265            observations.emit(observed_view_id, self, |callback, this| callback(this));
2266        }
2267    }
2268
2269    fn handle_entity_release_effect(&mut self, entity_id: usize, entity: &dyn Any) {
2270        self.release_observations
2271            .clone()
2272            .emit(entity_id, self, |callback, this| {
2273                callback(entity, this);
2274                // Release observations happen one time. So clear the callback by returning false
2275                false
2276            })
2277    }
2278
2279    fn handle_fullscreen_effect(&mut self, window_id: usize, is_fullscreen: bool) {
2280        //Short circuit evaluation if we're already g2g
2281        if self
2282            .windows
2283            .get(&window_id)
2284            .map(|w| w.is_fullscreen == is_fullscreen)
2285            .unwrap_or(false)
2286        {
2287            return;
2288        }
2289
2290        self.update(|this| {
2291            let window = this.windows.get_mut(&window_id)?;
2292            window.is_fullscreen = is_fullscreen;
2293
2294            let mut fullscreen_observations = this.window_fullscreen_observations.clone();
2295            fullscreen_observations.emit(window_id, this, |callback, this| {
2296                callback(is_fullscreen, this)
2297            });
2298
2299            if let Some((uuid, bounds)) = this
2300                .window_display_uuid(window_id)
2301                .zip(this.window_bounds(window_id))
2302            {
2303                let mut bounds_observations = this.window_bounds_observations.clone();
2304                bounds_observations.emit(window_id, this, |callback, this| {
2305                    callback(bounds, uuid, this)
2306                });
2307            }
2308
2309            Some(())
2310        });
2311    }
2312
2313    fn handle_keystroke_effect(
2314        &mut self,
2315        window_id: usize,
2316        keystroke: Keystroke,
2317        handled_by: Option<Box<dyn Action>>,
2318        result: MatchResult,
2319    ) {
2320        self.update(|this| {
2321            let mut observations = this.keystroke_observations.clone();
2322            observations.emit(window_id, this, {
2323                move |callback, this| callback(&keystroke, &result, handled_by.as_ref(), this)
2324            });
2325        });
2326    }
2327
2328    fn handle_window_activation_effect(&mut self, window_id: usize, active: bool) {
2329        //Short circuit evaluation if we're already g2g
2330        if self
2331            .windows
2332            .get(&window_id)
2333            .map(|w| w.is_active == active)
2334            .unwrap_or(false)
2335        {
2336            return;
2337        }
2338
2339        self.update(|this| {
2340            let window = this.windows.get_mut(&window_id)?;
2341            window.is_active = active;
2342
2343            //Handle focus
2344            let focused_id = window.focused_view_id?;
2345            for view_id in this.ancestors(window_id, focused_id).collect::<Vec<_>>() {
2346                if let Some(mut view) = this.views.remove(&(window_id, view_id)) {
2347                    if active {
2348                        view.focus_in(this, window_id, view_id, focused_id);
2349                    } else {
2350                        view.focus_out(this, window_id, view_id, focused_id);
2351                    }
2352                    this.views.insert((window_id, view_id), view);
2353                }
2354            }
2355
2356            let mut observations = this.window_activation_observations.clone();
2357            observations.emit(window_id, this, |callback, this| callback(active, this));
2358
2359            Some(())
2360        });
2361    }
2362
2363    fn handle_focus_effect(&mut self, window_id: usize, focused_id: Option<usize>) {
2364        if self
2365            .windows
2366            .get(&window_id)
2367            .map(|w| w.focused_view_id)
2368            .map_or(false, |cur_focused| cur_focused == focused_id)
2369        {
2370            return;
2371        }
2372
2373        self.update(|this| {
2374            let blurred_id = this.windows.get_mut(&window_id).and_then(|window| {
2375                let blurred_id = window.focused_view_id;
2376                window.focused_view_id = focused_id;
2377                blurred_id
2378            });
2379
2380            let blurred_parents = blurred_id
2381                .map(|blurred_id| this.ancestors(window_id, blurred_id).collect::<Vec<_>>())
2382                .unwrap_or_default();
2383            let focused_parents = focused_id
2384                .map(|focused_id| this.ancestors(window_id, focused_id).collect::<Vec<_>>())
2385                .unwrap_or_default();
2386
2387            if let Some(blurred_id) = blurred_id {
2388                for view_id in blurred_parents.iter().copied() {
2389                    if let Some(mut view) = this.views.remove(&(window_id, view_id)) {
2390                        view.focus_out(this, window_id, view_id, blurred_id);
2391                        this.views.insert((window_id, view_id), view);
2392                    }
2393                }
2394
2395                let mut subscriptions = this.focus_observations.clone();
2396                subscriptions.emit(blurred_id, this, |callback, this| callback(false, this));
2397            }
2398
2399            if let Some(focused_id) = focused_id {
2400                for view_id in focused_parents {
2401                    if let Some(mut view) = this.views.remove(&(window_id, view_id)) {
2402                        view.focus_in(this, window_id, view_id, focused_id);
2403                        this.views.insert((window_id, view_id), view);
2404                    }
2405                }
2406
2407                let mut subscriptions = this.focus_observations.clone();
2408                subscriptions.emit(focused_id, this, |callback, this| callback(true, this));
2409            }
2410        })
2411    }
2412
2413    fn handle_dispatch_action_from_effect(
2414        &mut self,
2415        window_id: usize,
2416        view_id: Option<usize>,
2417        action: &dyn Action,
2418    ) -> bool {
2419        self.update(|this| {
2420            if let Some(view_id) = view_id {
2421                this.halt_action_dispatch = false;
2422                this.visit_dispatch_path(window_id, view_id, |view_id, capture_phase, this| {
2423                    if let Some(mut view) = this.views.remove(&(window_id, view_id)) {
2424                        let type_id = view.as_any().type_id();
2425
2426                        if let Some((name, mut handlers)) = this
2427                            .actions_mut(capture_phase)
2428                            .get_mut(&type_id)
2429                            .and_then(|h| h.remove_entry(&action.id()))
2430                        {
2431                            for handler in handlers.iter_mut().rev() {
2432                                this.halt_action_dispatch = true;
2433                                handler(view.as_mut(), action, this, window_id, view_id);
2434                                if this.halt_action_dispatch {
2435                                    break;
2436                                }
2437                            }
2438                            this.actions_mut(capture_phase)
2439                                .get_mut(&type_id)
2440                                .unwrap()
2441                                .insert(name, handlers);
2442                        }
2443
2444                        this.views.insert((window_id, view_id), view);
2445                    }
2446
2447                    !this.halt_action_dispatch
2448                });
2449            }
2450
2451            if !this.halt_action_dispatch {
2452                this.halt_action_dispatch = this.dispatch_global_action_any(action);
2453            }
2454
2455            this.pending_effects
2456                .push_back(Effect::ActionDispatchNotification {
2457                    action_id: action.id(),
2458                });
2459            this.halt_action_dispatch
2460        })
2461    }
2462
2463    fn handle_action_dispatch_notification_effect(&mut self, action_id: TypeId) {
2464        self.action_dispatch_observations
2465            .clone()
2466            .emit((), self, |callback, this| {
2467                callback(action_id, this);
2468                true
2469            });
2470    }
2471
2472    fn handle_window_should_close_subscription_effect(
2473        &mut self,
2474        window_id: usize,
2475        mut callback: WindowShouldCloseSubscriptionCallback,
2476    ) {
2477        let mut app = self.upgrade();
2478        if let Some((_, window)) = self.presenters_and_platform_windows.get_mut(&window_id) {
2479            window.on_should_close(Box::new(move || app.update(|cx| callback(cx))))
2480        }
2481    }
2482
2483    fn handle_window_moved(&mut self, window_id: usize) {
2484        if let Some((display, bounds)) = self
2485            .window_display_uuid(window_id)
2486            .zip(self.window_bounds(window_id))
2487        {
2488            self.window_bounds_observations
2489                .clone()
2490                .emit(window_id, self, move |callback, this| {
2491                    callback(bounds, display, this);
2492                    true
2493                });
2494        }
2495    }
2496
2497    fn handle_active_labeled_tasks_changed_effect(&mut self) {
2498        self.active_labeled_task_observations
2499            .clone()
2500            .emit((), self, move |callback, this| {
2501                callback(this);
2502                true
2503            });
2504    }
2505
2506    pub fn focus(&mut self, window_id: usize, view_id: Option<usize>) {
2507        self.pending_effects
2508            .push_back(Effect::Focus { window_id, view_id });
2509    }
2510
2511    fn spawn_internal<F, Fut, T>(&mut self, task_name: Option<&'static str>, f: F) -> Task<T>
2512    where
2513        F: FnOnce(AsyncAppContext) -> Fut,
2514        Fut: 'static + Future<Output = T>,
2515        T: 'static,
2516    {
2517        let label_id = task_name.map(|task_name| {
2518            let id = post_inc(&mut self.next_labeled_task_id);
2519            self.active_labeled_tasks.insert(id, task_name);
2520            self.pending_effects
2521                .push_back(Effect::ActiveLabeledTasksChanged);
2522            id
2523        });
2524
2525        let future = f(self.to_async());
2526        let cx = self.to_async();
2527        self.foreground.spawn(async move {
2528            let result = future.await;
2529            let mut cx = cx.0.borrow_mut();
2530
2531            if let Some(completed_label_id) = label_id {
2532                cx.active_labeled_tasks.remove(&completed_label_id);
2533                cx.pending_effects
2534                    .push_back(Effect::ActiveLabeledTasksChanged);
2535            }
2536            cx.flush_effects();
2537            result
2538        })
2539    }
2540
2541    pub fn spawn_labeled<F, Fut, T>(&mut self, task_name: &'static str, f: F) -> Task<T>
2542    where
2543        F: FnOnce(AsyncAppContext) -> Fut,
2544        Fut: 'static + Future<Output = T>,
2545        T: 'static,
2546    {
2547        self.spawn_internal(Some(task_name), f)
2548    }
2549
2550    pub fn spawn<F, Fut, T>(&mut self, f: F) -> Task<T>
2551    where
2552        F: FnOnce(AsyncAppContext) -> Fut,
2553        Fut: 'static + Future<Output = T>,
2554        T: 'static,
2555    {
2556        self.spawn_internal(None, f)
2557    }
2558
2559    pub fn to_async(&self) -> AsyncAppContext {
2560        AsyncAppContext(self.weak_self.as_ref().unwrap().upgrade().unwrap())
2561    }
2562
2563    pub fn write_to_clipboard(&self, item: ClipboardItem) {
2564        self.platform.write_to_clipboard(item);
2565    }
2566
2567    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
2568        self.platform.read_from_clipboard()
2569    }
2570
2571    #[cfg(any(test, feature = "test-support"))]
2572    pub fn leak_detector(&self) -> Arc<Mutex<LeakDetector>> {
2573        self.ref_counts.lock().leak_detector.clone()
2574    }
2575}
2576
2577impl ReadModel for AppContext {
2578    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
2579        if let Some(model) = self.models.get(&handle.model_id) {
2580            model
2581                .as_any()
2582                .downcast_ref()
2583                .expect("downcast is type safe")
2584        } else {
2585            panic!("circular model reference");
2586        }
2587    }
2588}
2589
2590impl UpdateModel for AppContext {
2591    fn update_model<T: Entity, V>(
2592        &mut self,
2593        handle: &ModelHandle<T>,
2594        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> V,
2595    ) -> V {
2596        if let Some(mut model) = self.models.remove(&handle.model_id) {
2597            self.update(|this| {
2598                let mut cx = ModelContext::new(this, handle.model_id);
2599                let result = update(
2600                    model
2601                        .as_any_mut()
2602                        .downcast_mut()
2603                        .expect("downcast is type safe"),
2604                    &mut cx,
2605                );
2606                this.models.insert(handle.model_id, model);
2607                result
2608            })
2609        } else {
2610            panic!("circular model update");
2611        }
2612    }
2613}
2614
2615impl UpgradeModelHandle for AppContext {
2616    fn upgrade_model_handle<T: Entity>(
2617        &self,
2618        handle: &WeakModelHandle<T>,
2619    ) -> Option<ModelHandle<T>> {
2620        if self.models.contains_key(&handle.model_id) {
2621            Some(ModelHandle::new(handle.model_id, &self.ref_counts))
2622        } else {
2623            None
2624        }
2625    }
2626
2627    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
2628        self.models.contains_key(&handle.model_id)
2629    }
2630
2631    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
2632        if self.models.contains_key(&handle.model_id) {
2633            Some(AnyModelHandle::new(
2634                handle.model_id,
2635                handle.model_type,
2636                self.ref_counts.clone(),
2637            ))
2638        } else {
2639            None
2640        }
2641    }
2642}
2643
2644impl UpgradeViewHandle for AppContext {
2645    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
2646        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
2647            Some(ViewHandle::new(
2648                handle.window_id,
2649                handle.view_id,
2650                &self.ref_counts,
2651            ))
2652        } else {
2653            None
2654        }
2655    }
2656
2657    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
2658        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
2659            Some(AnyViewHandle::new(
2660                handle.window_id,
2661                handle.view_id,
2662                handle.view_type,
2663                self.ref_counts.clone(),
2664            ))
2665        } else {
2666            None
2667        }
2668    }
2669}
2670
2671impl ReadView for AppContext {
2672    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
2673        if let Some(view) = self.views.get(&(handle.window_id, handle.view_id)) {
2674            view.as_any().downcast_ref().expect("downcast is type safe")
2675        } else {
2676            panic!("circular view reference for type {}", type_name::<T>());
2677        }
2678    }
2679}
2680
2681impl UpdateView for AppContext {
2682    fn update_view<T, S>(
2683        &mut self,
2684        handle: &ViewHandle<T>,
2685        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
2686    ) -> S
2687    where
2688        T: View,
2689    {
2690        self.update(|this| {
2691            let mut view = this
2692                .views
2693                .remove(&(handle.window_id, handle.view_id))
2694                .expect("circular view update");
2695
2696            let mut cx = ViewContext::new(this, handle.window_id, handle.view_id);
2697            let result = update(
2698                view.as_any_mut()
2699                    .downcast_mut()
2700                    .expect("downcast is type safe"),
2701                &mut cx,
2702            );
2703            this.views.insert((handle.window_id, handle.view_id), view);
2704            result
2705        })
2706    }
2707}
2708
2709#[derive(Debug)]
2710pub enum ParentId {
2711    View(usize),
2712    Root,
2713}
2714
2715impl AppContext {
2716    pub fn root_view(&self, window_id: usize) -> Option<AnyViewHandle> {
2717        self.windows
2718            .get(&window_id)
2719            .map(|window| window.root_view.clone())
2720    }
2721
2722    pub fn root_view_id(&self, window_id: usize) -> Option<usize> {
2723        self.windows
2724            .get(&window_id)
2725            .map(|window| window.root_view.id())
2726    }
2727
2728    pub fn focused_view_id(&self, window_id: usize) -> Option<usize> {
2729        self.windows
2730            .get(&window_id)
2731            .and_then(|window| window.focused_view_id)
2732    }
2733
2734    pub fn view_ui_name(&self, window_id: usize, view_id: usize) -> Option<&'static str> {
2735        Some(self.views.get(&(window_id, view_id))?.ui_name())
2736    }
2737
2738    pub fn view_type_id(&self, window_id: usize, view_id: usize) -> Option<TypeId> {
2739        self.views
2740            .get(&(window_id, view_id))
2741            .map(|view| view.as_any().type_id())
2742    }
2743
2744    pub fn background(&self) -> &Arc<executor::Background> {
2745        &self.background
2746    }
2747
2748    pub fn font_cache(&self) -> &Arc<FontCache> {
2749        &self.font_cache
2750    }
2751
2752    pub fn platform(&self) -> &Arc<dyn Platform> {
2753        &self.platform
2754    }
2755
2756    pub fn has_global<T: 'static>(&self) -> bool {
2757        self.globals.contains_key(&TypeId::of::<T>())
2758    }
2759
2760    pub fn global<T: 'static>(&self) -> &T {
2761        if let Some(global) = self.globals.get(&TypeId::of::<T>()) {
2762            global.downcast_ref().unwrap()
2763        } else {
2764            panic!("no global has been added for {}", type_name::<T>());
2765        }
2766    }
2767
2768    /// Returns an iterator over all of the view ids from the passed view up to the root of the window
2769    /// Includes the passed view itself
2770    fn ancestors(&self, window_id: usize, mut view_id: usize) -> impl Iterator<Item = usize> + '_ {
2771        std::iter::once(view_id)
2772            .into_iter()
2773            .chain(std::iter::from_fn(move || {
2774                if let Some(ParentId::View(parent_id)) = self.parents.get(&(window_id, view_id)) {
2775                    view_id = *parent_id;
2776                    Some(view_id)
2777                } else {
2778                    None
2779                }
2780            }))
2781    }
2782
2783    /// Returns the id of the parent of the given view, or none if the given
2784    /// view is the root.
2785    pub fn parent(&self, window_id: usize, view_id: usize) -> Option<usize> {
2786        if let Some(ParentId::View(view_id)) = self.parents.get(&(window_id, view_id)) {
2787            Some(*view_id)
2788        } else {
2789            None
2790        }
2791    }
2792
2793    pub fn is_child_focused(&self, view: &AnyViewHandle) -> bool {
2794        if let Some(focused_view_id) = self.focused_view_id(view.window_id) {
2795            self.ancestors(view.window_id, focused_view_id)
2796                .skip(1) // Skip self id
2797                .any(|parent| parent == view.view_id)
2798        } else {
2799            false
2800        }
2801    }
2802}
2803
2804struct Window {
2805    root_view: AnyViewHandle,
2806    focused_view_id: Option<usize>,
2807    is_active: bool,
2808    is_fullscreen: bool,
2809    invalidation: Option<WindowInvalidation>,
2810}
2811
2812#[derive(Default, Clone)]
2813pub struct WindowInvalidation {
2814    pub updated: HashSet<usize>,
2815    pub removed: Vec<usize>,
2816}
2817
2818pub enum Effect {
2819    Subscription {
2820        entity_id: usize,
2821        subscription_id: usize,
2822        callback: SubscriptionCallback,
2823    },
2824    Event {
2825        entity_id: usize,
2826        payload: Box<dyn Any>,
2827    },
2828    GlobalSubscription {
2829        type_id: TypeId,
2830        subscription_id: usize,
2831        callback: GlobalSubscriptionCallback,
2832    },
2833    GlobalEvent {
2834        payload: Box<dyn Any>,
2835    },
2836    Observation {
2837        entity_id: usize,
2838        subscription_id: usize,
2839        callback: ObservationCallback,
2840    },
2841    ModelNotification {
2842        model_id: usize,
2843    },
2844    ViewNotification {
2845        window_id: usize,
2846        view_id: usize,
2847    },
2848    Deferred {
2849        callback: Box<dyn FnOnce(&mut AppContext)>,
2850        after_window_update: bool,
2851    },
2852    GlobalNotification {
2853        type_id: TypeId,
2854    },
2855    ModelRelease {
2856        model_id: usize,
2857        model: Box<dyn AnyModel>,
2858    },
2859    ViewRelease {
2860        view_id: usize,
2861        view: Box<dyn AnyView>,
2862    },
2863    Focus {
2864        window_id: usize,
2865        view_id: Option<usize>,
2866    },
2867    FocusObservation {
2868        view_id: usize,
2869        subscription_id: usize,
2870        callback: FocusObservationCallback,
2871    },
2872    ResizeWindow {
2873        window_id: usize,
2874    },
2875    MoveWindow {
2876        window_id: usize,
2877    },
2878    ActivateWindow {
2879        window_id: usize,
2880        is_active: bool,
2881    },
2882    WindowActivationObservation {
2883        window_id: usize,
2884        subscription_id: usize,
2885        callback: WindowActivationCallback,
2886    },
2887    FullscreenWindow {
2888        window_id: usize,
2889        is_fullscreen: bool,
2890    },
2891    WindowFullscreenObservation {
2892        window_id: usize,
2893        subscription_id: usize,
2894        callback: WindowFullscreenCallback,
2895    },
2896    WindowBoundsObservation {
2897        window_id: usize,
2898        subscription_id: usize,
2899        callback: WindowBoundsCallback,
2900    },
2901    Keystroke {
2902        window_id: usize,
2903        keystroke: Keystroke,
2904        handled_by: Option<Box<dyn Action>>,
2905        result: MatchResult,
2906    },
2907    RefreshWindows,
2908    DispatchActionFrom {
2909        window_id: usize,
2910        view_id: usize,
2911        action: Box<dyn Action>,
2912    },
2913    ActionDispatchNotification {
2914        action_id: TypeId,
2915    },
2916    WindowShouldCloseSubscription {
2917        window_id: usize,
2918        callback: WindowShouldCloseSubscriptionCallback,
2919    },
2920    ActiveLabeledTasksChanged,
2921    ActiveLabeledTasksObservation {
2922        subscription_id: usize,
2923        callback: ActiveLabeledTasksCallback,
2924    },
2925}
2926
2927impl Debug for Effect {
2928    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2929        match self {
2930            Effect::Subscription {
2931                entity_id,
2932                subscription_id,
2933                ..
2934            } => f
2935                .debug_struct("Effect::Subscribe")
2936                .field("entity_id", entity_id)
2937                .field("subscription_id", subscription_id)
2938                .finish(),
2939            Effect::Event { entity_id, .. } => f
2940                .debug_struct("Effect::Event")
2941                .field("entity_id", entity_id)
2942                .finish(),
2943            Effect::GlobalSubscription {
2944                type_id,
2945                subscription_id,
2946                ..
2947            } => f
2948                .debug_struct("Effect::Subscribe")
2949                .field("type_id", type_id)
2950                .field("subscription_id", subscription_id)
2951                .finish(),
2952            Effect::GlobalEvent { payload, .. } => f
2953                .debug_struct("Effect::GlobalEvent")
2954                .field("type_id", &(&*payload).type_id())
2955                .finish(),
2956            Effect::Observation {
2957                entity_id,
2958                subscription_id,
2959                ..
2960            } => f
2961                .debug_struct("Effect::Observation")
2962                .field("entity_id", entity_id)
2963                .field("subscription_id", subscription_id)
2964                .finish(),
2965            Effect::ModelNotification { model_id } => f
2966                .debug_struct("Effect::ModelNotification")
2967                .field("model_id", model_id)
2968                .finish(),
2969            Effect::ViewNotification { window_id, view_id } => f
2970                .debug_struct("Effect::ViewNotification")
2971                .field("window_id", window_id)
2972                .field("view_id", view_id)
2973                .finish(),
2974            Effect::GlobalNotification { type_id } => f
2975                .debug_struct("Effect::GlobalNotification")
2976                .field("type_id", type_id)
2977                .finish(),
2978            Effect::Deferred { .. } => f.debug_struct("Effect::Deferred").finish(),
2979            Effect::ModelRelease { model_id, .. } => f
2980                .debug_struct("Effect::ModelRelease")
2981                .field("model_id", model_id)
2982                .finish(),
2983            Effect::ViewRelease { view_id, .. } => f
2984                .debug_struct("Effect::ViewRelease")
2985                .field("view_id", view_id)
2986                .finish(),
2987            Effect::Focus { window_id, view_id } => f
2988                .debug_struct("Effect::Focus")
2989                .field("window_id", window_id)
2990                .field("view_id", view_id)
2991                .finish(),
2992            Effect::FocusObservation {
2993                view_id,
2994                subscription_id,
2995                ..
2996            } => f
2997                .debug_struct("Effect::FocusObservation")
2998                .field("view_id", view_id)
2999                .field("subscription_id", subscription_id)
3000                .finish(),
3001            Effect::DispatchActionFrom {
3002                window_id, view_id, ..
3003            } => f
3004                .debug_struct("Effect::DispatchActionFrom")
3005                .field("window_id", window_id)
3006                .field("view_id", view_id)
3007                .finish(),
3008            Effect::ActionDispatchNotification { action_id, .. } => f
3009                .debug_struct("Effect::ActionDispatchNotification")
3010                .field("action_id", action_id)
3011                .finish(),
3012            Effect::ResizeWindow { window_id } => f
3013                .debug_struct("Effect::RefreshWindow")
3014                .field("window_id", window_id)
3015                .finish(),
3016            Effect::MoveWindow { window_id } => f
3017                .debug_struct("Effect::MoveWindow")
3018                .field("window_id", window_id)
3019                .finish(),
3020            Effect::WindowActivationObservation {
3021                window_id,
3022                subscription_id,
3023                ..
3024            } => f
3025                .debug_struct("Effect::WindowActivationObservation")
3026                .field("window_id", window_id)
3027                .field("subscription_id", subscription_id)
3028                .finish(),
3029            Effect::ActivateWindow {
3030                window_id,
3031                is_active,
3032            } => f
3033                .debug_struct("Effect::ActivateWindow")
3034                .field("window_id", window_id)
3035                .field("is_active", is_active)
3036                .finish(),
3037            Effect::FullscreenWindow {
3038                window_id,
3039                is_fullscreen,
3040            } => f
3041                .debug_struct("Effect::FullscreenWindow")
3042                .field("window_id", window_id)
3043                .field("is_fullscreen", is_fullscreen)
3044                .finish(),
3045            Effect::WindowFullscreenObservation {
3046                window_id,
3047                subscription_id,
3048                callback: _,
3049            } => f
3050                .debug_struct("Effect::WindowFullscreenObservation")
3051                .field("window_id", window_id)
3052                .field("subscription_id", subscription_id)
3053                .finish(),
3054
3055            Effect::WindowBoundsObservation {
3056                window_id,
3057                subscription_id,
3058                callback: _,
3059            } => f
3060                .debug_struct("Effect::WindowBoundsObservation")
3061                .field("window_id", window_id)
3062                .field("subscription_id", subscription_id)
3063                .finish(),
3064            Effect::RefreshWindows => f.debug_struct("Effect::FullViewRefresh").finish(),
3065            Effect::WindowShouldCloseSubscription { window_id, .. } => f
3066                .debug_struct("Effect::WindowShouldCloseSubscription")
3067                .field("window_id", window_id)
3068                .finish(),
3069            Effect::Keystroke {
3070                window_id,
3071                keystroke,
3072                handled_by,
3073                result,
3074            } => f
3075                .debug_struct("Effect::Keystroke")
3076                .field("window_id", window_id)
3077                .field("keystroke", keystroke)
3078                .field(
3079                    "keystroke",
3080                    &handled_by.as_ref().map(|handled_by| handled_by.name()),
3081                )
3082                .field("result", result)
3083                .finish(),
3084            Effect::ActiveLabeledTasksChanged => {
3085                f.debug_struct("Effect::ActiveLabeledTasksChanged").finish()
3086            }
3087            Effect::ActiveLabeledTasksObservation {
3088                subscription_id,
3089                callback: _,
3090            } => f
3091                .debug_struct("Effect::ActiveLabeledTasksObservation")
3092                .field("subscription_id", subscription_id)
3093                .finish(),
3094        }
3095    }
3096}
3097
3098pub trait AnyModel {
3099    fn as_any(&self) -> &dyn Any;
3100    fn as_any_mut(&mut self) -> &mut dyn Any;
3101    fn release(&mut self, cx: &mut AppContext);
3102    fn app_will_quit(
3103        &mut self,
3104        cx: &mut AppContext,
3105    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
3106}
3107
3108impl<T> AnyModel for T
3109where
3110    T: Entity,
3111{
3112    fn as_any(&self) -> &dyn Any {
3113        self
3114    }
3115
3116    fn as_any_mut(&mut self) -> &mut dyn Any {
3117        self
3118    }
3119
3120    fn release(&mut self, cx: &mut AppContext) {
3121        self.release(cx);
3122    }
3123
3124    fn app_will_quit(
3125        &mut self,
3126        cx: &mut AppContext,
3127    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
3128        self.app_will_quit(cx)
3129    }
3130}
3131
3132pub trait AnyView {
3133    fn as_any(&self) -> &dyn Any;
3134    fn as_any_mut(&mut self) -> &mut dyn Any;
3135    fn release(&mut self, cx: &mut AppContext);
3136    fn app_will_quit(
3137        &mut self,
3138        cx: &mut AppContext,
3139    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
3140    fn ui_name(&self) -> &'static str;
3141    fn render(&mut self, params: RenderParams, cx: &mut AppContext) -> ElementBox;
3142    fn focus_in(
3143        &mut self,
3144        cx: &mut AppContext,
3145        window_id: usize,
3146        view_id: usize,
3147        focused_id: usize,
3148    );
3149    fn focus_out(
3150        &mut self,
3151        cx: &mut AppContext,
3152        window_id: usize,
3153        view_id: usize,
3154        focused_id: usize,
3155    );
3156    fn key_down(
3157        &mut self,
3158        event: &KeyDownEvent,
3159        cx: &mut AppContext,
3160        window_id: usize,
3161        view_id: usize,
3162    ) -> bool;
3163    fn key_up(
3164        &mut self,
3165        event: &KeyUpEvent,
3166        cx: &mut AppContext,
3167        window_id: usize,
3168        view_id: usize,
3169    ) -> bool;
3170    fn modifiers_changed(
3171        &mut self,
3172        event: &ModifiersChangedEvent,
3173        cx: &mut AppContext,
3174        window_id: usize,
3175        view_id: usize,
3176    ) -> bool;
3177    fn keymap_context(&self, cx: &AppContext) -> KeymapContext;
3178    fn debug_json(&self, cx: &AppContext) -> serde_json::Value;
3179
3180    fn text_for_range(&self, range: Range<usize>, cx: &AppContext) -> Option<String>;
3181    fn selected_text_range(&self, cx: &AppContext) -> Option<Range<usize>>;
3182    fn marked_text_range(&self, cx: &AppContext) -> Option<Range<usize>>;
3183    fn unmark_text(&mut self, cx: &mut AppContext, window_id: usize, view_id: usize);
3184    fn replace_text_in_range(
3185        &mut self,
3186        range: Option<Range<usize>>,
3187        text: &str,
3188        cx: &mut AppContext,
3189        window_id: usize,
3190        view_id: usize,
3191    );
3192    fn replace_and_mark_text_in_range(
3193        &mut self,
3194        range: Option<Range<usize>>,
3195        new_text: &str,
3196        new_selected_range: Option<Range<usize>>,
3197        cx: &mut AppContext,
3198        window_id: usize,
3199        view_id: usize,
3200    );
3201    fn any_handle(&self, window_id: usize, view_id: usize, cx: &AppContext) -> AnyViewHandle {
3202        AnyViewHandle::new(
3203            window_id,
3204            view_id,
3205            self.as_any().type_id(),
3206            cx.ref_counts.clone(),
3207        )
3208    }
3209}
3210
3211impl<T> AnyView for T
3212where
3213    T: View,
3214{
3215    fn as_any(&self) -> &dyn Any {
3216        self
3217    }
3218
3219    fn as_any_mut(&mut self) -> &mut dyn Any {
3220        self
3221    }
3222
3223    fn release(&mut self, cx: &mut AppContext) {
3224        self.release(cx);
3225    }
3226
3227    fn app_will_quit(
3228        &mut self,
3229        cx: &mut AppContext,
3230    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
3231        self.app_will_quit(cx)
3232    }
3233
3234    fn ui_name(&self) -> &'static str {
3235        T::ui_name()
3236    }
3237
3238    fn render(&mut self, params: RenderParams, cx: &mut AppContext) -> ElementBox {
3239        View::render(self, &mut RenderContext::new(params, cx))
3240    }
3241
3242    fn focus_in(
3243        &mut self,
3244        cx: &mut AppContext,
3245        window_id: usize,
3246        view_id: usize,
3247        focused_id: usize,
3248    ) {
3249        let mut cx = ViewContext::new(cx, window_id, view_id);
3250        let focused_view_handle: AnyViewHandle = if view_id == focused_id {
3251            cx.handle().into_any()
3252        } else {
3253            let focused_type = cx
3254                .views
3255                .get(&(window_id, focused_id))
3256                .unwrap()
3257                .as_any()
3258                .type_id();
3259            AnyViewHandle::new(window_id, focused_id, focused_type, cx.ref_counts.clone())
3260        };
3261        View::focus_in(self, focused_view_handle, &mut cx);
3262    }
3263
3264    fn focus_out(
3265        &mut self,
3266        cx: &mut AppContext,
3267        window_id: usize,
3268        view_id: usize,
3269        blurred_id: usize,
3270    ) {
3271        let mut cx = ViewContext::new(cx, window_id, view_id);
3272        let blurred_view_handle: AnyViewHandle = if view_id == blurred_id {
3273            cx.handle().into_any()
3274        } else {
3275            let blurred_type = cx
3276                .views
3277                .get(&(window_id, blurred_id))
3278                .unwrap()
3279                .as_any()
3280                .type_id();
3281            AnyViewHandle::new(window_id, blurred_id, blurred_type, cx.ref_counts.clone())
3282        };
3283        View::focus_out(self, blurred_view_handle, &mut cx);
3284    }
3285
3286    fn key_down(
3287        &mut self,
3288        event: &KeyDownEvent,
3289        cx: &mut AppContext,
3290        window_id: usize,
3291        view_id: usize,
3292    ) -> bool {
3293        let mut cx = ViewContext::new(cx, window_id, view_id);
3294        View::key_down(self, event, &mut cx)
3295    }
3296
3297    fn key_up(
3298        &mut self,
3299        event: &KeyUpEvent,
3300        cx: &mut AppContext,
3301        window_id: usize,
3302        view_id: usize,
3303    ) -> bool {
3304        let mut cx = ViewContext::new(cx, window_id, view_id);
3305        View::key_up(self, event, &mut cx)
3306    }
3307
3308    fn modifiers_changed(
3309        &mut self,
3310        event: &ModifiersChangedEvent,
3311        cx: &mut AppContext,
3312        window_id: usize,
3313        view_id: usize,
3314    ) -> bool {
3315        let mut cx = ViewContext::new(cx, window_id, view_id);
3316        View::modifiers_changed(self, event, &mut cx)
3317    }
3318
3319    fn keymap_context(&self, cx: &AppContext) -> KeymapContext {
3320        View::keymap_context(self, cx)
3321    }
3322
3323    fn debug_json(&self, cx: &AppContext) -> serde_json::Value {
3324        View::debug_json(self, cx)
3325    }
3326
3327    fn text_for_range(&self, range: Range<usize>, cx: &AppContext) -> Option<String> {
3328        View::text_for_range(self, range, cx)
3329    }
3330
3331    fn selected_text_range(&self, cx: &AppContext) -> Option<Range<usize>> {
3332        View::selected_text_range(self, cx)
3333    }
3334
3335    fn marked_text_range(&self, cx: &AppContext) -> Option<Range<usize>> {
3336        View::marked_text_range(self, cx)
3337    }
3338
3339    fn unmark_text(&mut self, cx: &mut AppContext, window_id: usize, view_id: usize) {
3340        let mut cx = ViewContext::new(cx, window_id, view_id);
3341        View::unmark_text(self, &mut cx)
3342    }
3343
3344    fn replace_text_in_range(
3345        &mut self,
3346        range: Option<Range<usize>>,
3347        text: &str,
3348        cx: &mut AppContext,
3349        window_id: usize,
3350        view_id: usize,
3351    ) {
3352        let mut cx = ViewContext::new(cx, window_id, view_id);
3353        View::replace_text_in_range(self, range, text, &mut cx)
3354    }
3355
3356    fn replace_and_mark_text_in_range(
3357        &mut self,
3358        range: Option<Range<usize>>,
3359        new_text: &str,
3360        new_selected_range: Option<Range<usize>>,
3361        cx: &mut AppContext,
3362        window_id: usize,
3363        view_id: usize,
3364    ) {
3365        let mut cx = ViewContext::new(cx, window_id, view_id);
3366        View::replace_and_mark_text_in_range(self, range, new_text, new_selected_range, &mut cx)
3367    }
3368}
3369
3370pub struct ModelContext<'a, T: ?Sized> {
3371    app: &'a mut AppContext,
3372    model_id: usize,
3373    model_type: PhantomData<T>,
3374    halt_stream: bool,
3375}
3376
3377impl<'a, T: Entity> ModelContext<'a, T> {
3378    fn new(app: &'a mut AppContext, model_id: usize) -> Self {
3379        Self {
3380            app,
3381            model_id,
3382            model_type: PhantomData,
3383            halt_stream: false,
3384        }
3385    }
3386
3387    pub fn background(&self) -> &Arc<executor::Background> {
3388        &self.app.background
3389    }
3390
3391    pub fn halt_stream(&mut self) {
3392        self.halt_stream = true;
3393    }
3394
3395    pub fn model_id(&self) -> usize {
3396        self.model_id
3397    }
3398
3399    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
3400    where
3401        S: Entity,
3402        F: FnOnce(&mut ModelContext<S>) -> S,
3403    {
3404        self.app.add_model(build_model)
3405    }
3406
3407    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut T, &mut ModelContext<T>)) {
3408        let handle = self.handle();
3409        self.app.defer(move |cx| {
3410            handle.update(cx, |model, cx| {
3411                callback(model, cx);
3412            })
3413        })
3414    }
3415
3416    pub fn emit(&mut self, payload: T::Event) {
3417        self.app.pending_effects.push_back(Effect::Event {
3418            entity_id: self.model_id,
3419            payload: Box::new(payload),
3420        });
3421    }
3422
3423    pub fn notify(&mut self) {
3424        self.app.notify_model(self.model_id);
3425    }
3426
3427    pub fn subscribe<S: Entity, F>(
3428        &mut self,
3429        handle: &ModelHandle<S>,
3430        mut callback: F,
3431    ) -> Subscription
3432    where
3433        S::Event: 'static,
3434        F: 'static + FnMut(&mut T, ModelHandle<S>, &S::Event, &mut ModelContext<T>),
3435    {
3436        let subscriber = self.weak_handle();
3437        self.app
3438            .subscribe_internal(handle, move |emitter, event, cx| {
3439                if let Some(subscriber) = subscriber.upgrade(cx) {
3440                    subscriber.update(cx, |subscriber, cx| {
3441                        callback(subscriber, emitter, event, cx);
3442                    });
3443                    true
3444                } else {
3445                    false
3446                }
3447            })
3448    }
3449
3450    pub fn observe<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F) -> Subscription
3451    where
3452        S: Entity,
3453        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ModelContext<T>),
3454    {
3455        let observer = self.weak_handle();
3456        self.app.observe_internal(handle, move |observed, cx| {
3457            if let Some(observer) = observer.upgrade(cx) {
3458                observer.update(cx, |observer, cx| {
3459                    callback(observer, observed, cx);
3460                });
3461                true
3462            } else {
3463                false
3464            }
3465        })
3466    }
3467
3468    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
3469    where
3470        G: Any,
3471        F: 'static + FnMut(&mut T, &mut ModelContext<T>),
3472    {
3473        let observer = self.weak_handle();
3474        self.app.observe_global::<G, _>(move |cx| {
3475            if let Some(observer) = observer.upgrade(cx) {
3476                observer.update(cx, |observer, cx| callback(observer, cx));
3477            }
3478        })
3479    }
3480
3481    pub fn observe_release<S, F>(
3482        &mut self,
3483        handle: &ModelHandle<S>,
3484        mut callback: F,
3485    ) -> Subscription
3486    where
3487        S: Entity,
3488        F: 'static + FnMut(&mut T, &S, &mut ModelContext<T>),
3489    {
3490        let observer = self.weak_handle();
3491        self.app.observe_release(handle, move |released, cx| {
3492            if let Some(observer) = observer.upgrade(cx) {
3493                observer.update(cx, |observer, cx| {
3494                    callback(observer, released, cx);
3495                });
3496            }
3497        })
3498    }
3499
3500    pub fn handle(&self) -> ModelHandle<T> {
3501        ModelHandle::new(self.model_id, &self.app.ref_counts)
3502    }
3503
3504    pub fn weak_handle(&self) -> WeakModelHandle<T> {
3505        WeakModelHandle::new(self.model_id)
3506    }
3507
3508    pub fn spawn<F, Fut, S>(&mut self, f: F) -> Task<S>
3509    where
3510        F: FnOnce(ModelHandle<T>, AsyncAppContext) -> Fut,
3511        Fut: 'static + Future<Output = S>,
3512        S: 'static,
3513    {
3514        let handle = self.handle();
3515        self.app.spawn(|cx| f(handle, cx))
3516    }
3517
3518    pub fn spawn_weak<F, Fut, S>(&mut self, f: F) -> Task<S>
3519    where
3520        F: FnOnce(WeakModelHandle<T>, AsyncAppContext) -> Fut,
3521        Fut: 'static + Future<Output = S>,
3522        S: 'static,
3523    {
3524        let handle = self.weak_handle();
3525        self.app.spawn(|cx| f(handle, cx))
3526    }
3527}
3528
3529impl<M> AsRef<AppContext> for ModelContext<'_, M> {
3530    fn as_ref(&self) -> &AppContext {
3531        &self.app
3532    }
3533}
3534
3535impl<M> AsMut<AppContext> for ModelContext<'_, M> {
3536    fn as_mut(&mut self) -> &mut AppContext {
3537        self.app
3538    }
3539}
3540
3541impl<M> ReadModel for ModelContext<'_, M> {
3542    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
3543        self.app.read_model(handle)
3544    }
3545}
3546
3547impl<M> UpdateModel for ModelContext<'_, M> {
3548    fn update_model<T: Entity, V>(
3549        &mut self,
3550        handle: &ModelHandle<T>,
3551        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> V,
3552    ) -> V {
3553        self.app.update_model(handle, update)
3554    }
3555}
3556
3557impl<M> UpgradeModelHandle for ModelContext<'_, M> {
3558    fn upgrade_model_handle<T: Entity>(
3559        &self,
3560        handle: &WeakModelHandle<T>,
3561    ) -> Option<ModelHandle<T>> {
3562        self.app.upgrade_model_handle(handle)
3563    }
3564
3565    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
3566        self.app.model_handle_is_upgradable(handle)
3567    }
3568
3569    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
3570        self.app.upgrade_any_model_handle(handle)
3571    }
3572}
3573
3574impl<M> Deref for ModelContext<'_, M> {
3575    type Target = AppContext;
3576
3577    fn deref(&self) -> &Self::Target {
3578        self.app
3579    }
3580}
3581
3582impl<M> DerefMut for ModelContext<'_, M> {
3583    fn deref_mut(&mut self) -> &mut Self::Target {
3584        &mut self.app
3585    }
3586}
3587
3588pub struct ViewContext<'a, T: ?Sized> {
3589    app: &'a mut AppContext,
3590    window_id: usize,
3591    view_id: usize,
3592    view_type: PhantomData<T>,
3593}
3594
3595impl<'a, T: View> ViewContext<'a, T> {
3596    fn new(app: &'a mut AppContext, window_id: usize, view_id: usize) -> Self {
3597        Self {
3598            app,
3599            window_id,
3600            view_id,
3601            view_type: PhantomData,
3602        }
3603    }
3604
3605    pub fn handle(&self) -> ViewHandle<T> {
3606        ViewHandle::new(self.window_id, self.view_id, &self.app.ref_counts)
3607    }
3608
3609    pub fn weak_handle(&self) -> WeakViewHandle<T> {
3610        WeakViewHandle::new(self.window_id, self.view_id)
3611    }
3612
3613    pub fn parent(&self) -> Option<usize> {
3614        self.app.parent(self.window_id, self.view_id)
3615    }
3616
3617    pub fn window_id(&self) -> usize {
3618        self.window_id
3619    }
3620
3621    pub fn view_id(&self) -> usize {
3622        self.view_id
3623    }
3624
3625    pub fn foreground(&self) -> &Rc<executor::Foreground> {
3626        self.app.foreground()
3627    }
3628
3629    pub fn background_executor(&self) -> &Arc<executor::Background> {
3630        &self.app.background
3631    }
3632
3633    pub fn platform(&self) -> &Arc<dyn Platform> {
3634        self.app.platform()
3635    }
3636
3637    pub fn show_character_palette(&self) {
3638        self.app.show_character_palette(self.window_id);
3639    }
3640
3641    pub fn minimize_window(&self) {
3642        self.app.minimize_window(self.window_id)
3643    }
3644
3645    pub fn zoom_window(&self) {
3646        self.app.zoom_window(self.window_id)
3647    }
3648
3649    pub fn toggle_full_screen(&self) {
3650        self.app.toggle_window_full_screen(self.window_id)
3651    }
3652
3653    pub fn prompt(
3654        &self,
3655        level: PromptLevel,
3656        msg: &str,
3657        answers: &[&str],
3658    ) -> oneshot::Receiver<usize> {
3659        self.app.prompt(self.window_id, level, msg, answers)
3660    }
3661
3662    pub fn prompt_for_paths(
3663        &self,
3664        options: PathPromptOptions,
3665    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
3666        self.app.prompt_for_paths(options)
3667    }
3668
3669    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
3670        self.app.prompt_for_new_path(directory)
3671    }
3672
3673    pub fn reveal_path(&self, path: &Path) {
3674        self.app.reveal_path(path)
3675    }
3676
3677    pub fn debug_elements(&self) -> crate::json::Value {
3678        self.app.debug_elements(self.window_id).unwrap()
3679    }
3680
3681    pub fn focus(&mut self, handle: &AnyViewHandle) {
3682        self.app.focus(handle.window_id, Some(handle.view_id));
3683    }
3684
3685    pub fn focus_self(&mut self) {
3686        self.app.focus(self.window_id, Some(self.view_id));
3687    }
3688
3689    pub fn is_self_focused(&self) -> bool {
3690        self.app.focused_view_id(self.window_id) == Some(self.view_id)
3691    }
3692
3693    pub fn is_child(&self, view: impl Into<AnyViewHandle>) -> bool {
3694        let view = view.into();
3695        if self.window_id != view.window_id {
3696            return false;
3697        }
3698        self.ancestors(view.window_id, view.view_id)
3699            .skip(1) // Skip self id
3700            .any(|parent| parent == self.view_id)
3701    }
3702
3703    pub fn blur(&mut self) {
3704        self.app.focus(self.window_id, None);
3705    }
3706
3707    pub fn set_window_title(&mut self, title: &str) {
3708        let window_id = self.window_id();
3709        if let Some((_, window)) = self.presenters_and_platform_windows.get_mut(&window_id) {
3710            window.set_title(title);
3711        }
3712    }
3713
3714    pub fn set_window_edited(&mut self, edited: bool) {
3715        let window_id = self.window_id();
3716        if let Some((_, window)) = self.presenters_and_platform_windows.get_mut(&window_id) {
3717            window.set_edited(edited);
3718        }
3719    }
3720
3721    pub fn on_window_should_close<F>(&mut self, mut callback: F)
3722    where
3723        F: 'static + FnMut(&mut T, &mut ViewContext<T>) -> bool,
3724    {
3725        let window_id = self.window_id();
3726        let view = self.weak_handle();
3727        self.pending_effects
3728            .push_back(Effect::WindowShouldCloseSubscription {
3729                window_id,
3730                callback: Box::new(move |cx| {
3731                    if let Some(view) = view.upgrade(cx) {
3732                        view.update(cx, |view, cx| callback(view, cx))
3733                    } else {
3734                        true
3735                    }
3736                }),
3737            });
3738    }
3739
3740    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
3741    where
3742        S: Entity,
3743        F: FnOnce(&mut ModelContext<S>) -> S,
3744    {
3745        self.app.add_model(build_model)
3746    }
3747
3748    pub fn add_view<S, F>(&mut self, build_view: F) -> ViewHandle<S>
3749    where
3750        S: View,
3751        F: FnOnce(&mut ViewContext<S>) -> S,
3752    {
3753        self.app
3754            .build_and_insert_view(self.window_id, ParentId::View(self.view_id), |cx| {
3755                Some(build_view(cx))
3756            })
3757            .unwrap()
3758    }
3759
3760    pub fn add_option_view<S, F>(&mut self, build_view: F) -> Option<ViewHandle<S>>
3761    where
3762        S: View,
3763        F: FnOnce(&mut ViewContext<S>) -> Option<S>,
3764    {
3765        self.app
3766            .build_and_insert_view(self.window_id, ParentId::View(self.view_id), build_view)
3767    }
3768
3769    pub fn reparent(&mut self, view_handle: &AnyViewHandle) {
3770        if self.window_id != view_handle.window_id {
3771            panic!("Can't reparent view to a view from a different window");
3772        }
3773        self.parents
3774            .remove(&(view_handle.window_id, view_handle.view_id));
3775        let new_parent_id = self.view_id;
3776        self.parents.insert(
3777            (view_handle.window_id, view_handle.view_id),
3778            ParentId::View(new_parent_id),
3779        );
3780    }
3781
3782    pub fn replace_root_view<V, F>(&mut self, build_root_view: F) -> ViewHandle<V>
3783    where
3784        V: View,
3785        F: FnOnce(&mut ViewContext<V>) -> V,
3786    {
3787        let window_id = self.window_id;
3788        self.update(|this| {
3789            let root_view = this
3790                .build_and_insert_view(window_id, ParentId::Root, |cx| Some(build_root_view(cx)))
3791                .unwrap();
3792            let window = this.windows.get_mut(&window_id).unwrap();
3793            window.root_view = root_view.clone().into_any();
3794            window.focused_view_id = Some(root_view.id());
3795            root_view
3796        })
3797    }
3798
3799    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
3800    where
3801        E: Entity,
3802        E::Event: 'static,
3803        H: Handle<E>,
3804        F: 'static + FnMut(&mut T, H, &E::Event, &mut ViewContext<T>),
3805    {
3806        let subscriber = self.weak_handle();
3807        self.app
3808            .subscribe_internal(handle, move |emitter, event, cx| {
3809                if let Some(subscriber) = subscriber.upgrade(cx) {
3810                    subscriber.update(cx, |subscriber, cx| {
3811                        callback(subscriber, emitter, event, cx);
3812                    });
3813                    true
3814                } else {
3815                    false
3816                }
3817            })
3818    }
3819
3820    pub fn observe<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
3821    where
3822        E: Entity,
3823        H: Handle<E>,
3824        F: 'static + FnMut(&mut T, H, &mut ViewContext<T>),
3825    {
3826        let observer = self.weak_handle();
3827        self.app.observe_internal(handle, move |observed, cx| {
3828            if let Some(observer) = observer.upgrade(cx) {
3829                observer.update(cx, |observer, cx| {
3830                    callback(observer, observed, cx);
3831                });
3832                true
3833            } else {
3834                false
3835            }
3836        })
3837    }
3838
3839    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
3840    where
3841        G: Any,
3842        F: 'static + FnMut(&mut T, &mut ViewContext<T>),
3843    {
3844        let observer = self.weak_handle();
3845        self.app.observe_global::<G, _>(move |cx| {
3846            if let Some(observer) = observer.upgrade(cx) {
3847                observer.update(cx, |observer, cx| callback(observer, cx));
3848            }
3849        })
3850    }
3851
3852    pub fn observe_focus<F, V>(&mut self, handle: &ViewHandle<V>, mut callback: F) -> Subscription
3853    where
3854        F: 'static + FnMut(&mut T, ViewHandle<V>, bool, &mut ViewContext<T>),
3855        V: View,
3856    {
3857        let observer = self.weak_handle();
3858        self.app
3859            .observe_focus(handle, move |observed, focused, cx| {
3860                if let Some(observer) = observer.upgrade(cx) {
3861                    observer.update(cx, |observer, cx| {
3862                        callback(observer, observed, focused, cx);
3863                    });
3864                    true
3865                } else {
3866                    false
3867                }
3868            })
3869    }
3870
3871    pub fn observe_release<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
3872    where
3873        E: Entity,
3874        H: Handle<E>,
3875        F: 'static + FnMut(&mut T, &E, &mut ViewContext<T>),
3876    {
3877        let observer = self.weak_handle();
3878        self.app.observe_release(handle, move |released, cx| {
3879            if let Some(observer) = observer.upgrade(cx) {
3880                observer.update(cx, |observer, cx| {
3881                    callback(observer, released, cx);
3882                });
3883            }
3884        })
3885    }
3886
3887    pub fn observe_actions<F>(&mut self, mut callback: F) -> Subscription
3888    where
3889        F: 'static + FnMut(&mut T, TypeId, &mut ViewContext<T>),
3890    {
3891        let observer = self.weak_handle();
3892        self.app.observe_actions(move |action_id, cx| {
3893            if let Some(observer) = observer.upgrade(cx) {
3894                observer.update(cx, |observer, cx| {
3895                    callback(observer, action_id, cx);
3896                });
3897            }
3898        })
3899    }
3900
3901    pub fn observe_window_activation<F>(&mut self, mut callback: F) -> Subscription
3902    where
3903        F: 'static + FnMut(&mut T, bool, &mut ViewContext<T>),
3904    {
3905        let observer = self.weak_handle();
3906        self.app
3907            .observe_window_activation(self.window_id(), move |active, cx| {
3908                if let Some(observer) = observer.upgrade(cx) {
3909                    observer.update(cx, |observer, cx| {
3910                        callback(observer, active, cx);
3911                    });
3912                    true
3913                } else {
3914                    false
3915                }
3916            })
3917    }
3918
3919    pub fn observe_fullscreen<F>(&mut self, mut callback: F) -> Subscription
3920    where
3921        F: 'static + FnMut(&mut T, bool, &mut ViewContext<T>),
3922    {
3923        let observer = self.weak_handle();
3924        self.app
3925            .observe_fullscreen(self.window_id(), move |active, cx| {
3926                if let Some(observer) = observer.upgrade(cx) {
3927                    observer.update(cx, |observer, cx| {
3928                        callback(observer, active, cx);
3929                    });
3930                    true
3931                } else {
3932                    false
3933                }
3934            })
3935    }
3936
3937    pub fn observe_keystrokes<F>(&mut self, mut callback: F) -> Subscription
3938    where
3939        F: 'static
3940            + FnMut(
3941                &mut T,
3942                &Keystroke,
3943                Option<&Box<dyn Action>>,
3944                &MatchResult,
3945                &mut ViewContext<T>,
3946            ) -> bool,
3947    {
3948        let observer = self.weak_handle();
3949        self.app.observe_keystrokes(
3950            self.window_id(),
3951            move |keystroke, result, handled_by, cx| {
3952                if let Some(observer) = observer.upgrade(cx) {
3953                    observer.update(cx, |observer, cx| {
3954                        callback(observer, keystroke, handled_by, result, cx);
3955                    });
3956                    true
3957                } else {
3958                    false
3959                }
3960            },
3961        )
3962    }
3963
3964    pub fn observe_window_bounds<F>(&mut self, mut callback: F) -> Subscription
3965    where
3966        F: 'static + FnMut(&mut T, WindowBounds, Uuid, &mut ViewContext<T>),
3967    {
3968        let observer = self.weak_handle();
3969        self.app
3970            .observe_window_bounds(self.window_id(), move |bounds, display, cx| {
3971                if let Some(observer) = observer.upgrade(cx) {
3972                    observer.update(cx, |observer, cx| {
3973                        callback(observer, bounds, display, cx);
3974                    });
3975                    true
3976                } else {
3977                    false
3978                }
3979            })
3980    }
3981
3982    pub fn observe_active_labeled_tasks<F>(&mut self, mut callback: F) -> Subscription
3983    where
3984        F: 'static + FnMut(&mut T, &mut ViewContext<T>),
3985    {
3986        let observer = self.weak_handle();
3987        self.app.observe_active_labeled_tasks(move |cx| {
3988            if let Some(observer) = observer.upgrade(cx) {
3989                observer.update(cx, |observer, cx| {
3990                    callback(observer, cx);
3991                });
3992                true
3993            } else {
3994                false
3995            }
3996        })
3997    }
3998
3999    pub fn emit(&mut self, payload: T::Event) {
4000        self.app.pending_effects.push_back(Effect::Event {
4001            entity_id: self.view_id,
4002            payload: Box::new(payload),
4003        });
4004    }
4005
4006    pub fn notify(&mut self) {
4007        self.app.notify_view(self.window_id, self.view_id);
4008    }
4009
4010    pub fn dispatch_action(&mut self, action: impl Action) {
4011        self.app
4012            .dispatch_action_at(self.window_id, self.view_id, action)
4013    }
4014
4015    pub fn dispatch_any_action(&mut self, action: Box<dyn Action>) {
4016        self.app
4017            .dispatch_any_action_at(self.window_id, self.view_id, action)
4018    }
4019
4020    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut T, &mut ViewContext<T>)) {
4021        let handle = self.handle();
4022        self.app.defer(move |cx| {
4023            handle.update(cx, |view, cx| {
4024                callback(view, cx);
4025            })
4026        })
4027    }
4028
4029    pub fn after_window_update(
4030        &mut self,
4031        callback: impl 'static + FnOnce(&mut T, &mut ViewContext<T>),
4032    ) {
4033        let handle = self.handle();
4034        self.app.after_window_update(move |cx| {
4035            handle.update(cx, |view, cx| {
4036                callback(view, cx);
4037            })
4038        })
4039    }
4040
4041    pub fn propagate_action(&mut self) {
4042        self.app.halt_action_dispatch = false;
4043    }
4044
4045    pub fn spawn_labeled<F, Fut, S>(&mut self, task_label: &'static str, f: F) -> Task<S>
4046    where
4047        F: FnOnce(ViewHandle<T>, AsyncAppContext) -> Fut,
4048        Fut: 'static + Future<Output = S>,
4049        S: 'static,
4050    {
4051        let handle = self.handle();
4052        self.app.spawn_labeled(task_label, |cx| f(handle, cx))
4053    }
4054
4055    pub fn spawn<F, Fut, S>(&mut self, f: F) -> Task<S>
4056    where
4057        F: FnOnce(ViewHandle<T>, AsyncAppContext) -> Fut,
4058        Fut: 'static + Future<Output = S>,
4059        S: 'static,
4060    {
4061        let handle = self.handle();
4062        self.app.spawn(|cx| f(handle, cx))
4063    }
4064
4065    pub fn spawn_weak<F, Fut, S>(&mut self, f: F) -> Task<S>
4066    where
4067        F: FnOnce(WeakViewHandle<T>, AsyncAppContext) -> Fut,
4068        Fut: 'static + Future<Output = S>,
4069        S: 'static,
4070    {
4071        let handle = self.weak_handle();
4072        self.app.spawn(|cx| f(handle, cx))
4073    }
4074}
4075
4076pub struct RenderParams {
4077    pub window_id: usize,
4078    pub view_id: usize,
4079    pub titlebar_height: f32,
4080    pub hovered_region_ids: HashSet<MouseRegionId>,
4081    pub clicked_region_ids: Option<(HashSet<MouseRegionId>, MouseButton)>,
4082    pub refreshing: bool,
4083    pub appearance: Appearance,
4084}
4085
4086pub struct RenderContext<'a, T: View> {
4087    pub(crate) window_id: usize,
4088    pub(crate) view_id: usize,
4089    pub(crate) view_type: PhantomData<T>,
4090    pub(crate) hovered_region_ids: HashSet<MouseRegionId>,
4091    pub(crate) clicked_region_ids: Option<(HashSet<MouseRegionId>, MouseButton)>,
4092    pub app: &'a mut AppContext,
4093    pub titlebar_height: f32,
4094    pub appearance: Appearance,
4095    pub refreshing: bool,
4096}
4097
4098#[derive(Debug, Clone, Default)]
4099pub struct MouseState {
4100    pub(crate) hovered: bool,
4101    pub(crate) clicked: Option<MouseButton>,
4102    pub(crate) accessed_hovered: bool,
4103    pub(crate) accessed_clicked: bool,
4104}
4105
4106impl MouseState {
4107    pub fn hovered(&mut self) -> bool {
4108        self.accessed_hovered = true;
4109        self.hovered
4110    }
4111
4112    pub fn clicked(&mut self) -> Option<MouseButton> {
4113        self.accessed_clicked = true;
4114        self.clicked
4115    }
4116
4117    pub fn accessed_hovered(&self) -> bool {
4118        self.accessed_hovered
4119    }
4120
4121    pub fn accessed_clicked(&self) -> bool {
4122        self.accessed_clicked
4123    }
4124}
4125
4126impl<'a, V: View> RenderContext<'a, V> {
4127    fn new(params: RenderParams, app: &'a mut AppContext) -> Self {
4128        Self {
4129            app,
4130            window_id: params.window_id,
4131            view_id: params.view_id,
4132            view_type: PhantomData,
4133            titlebar_height: params.titlebar_height,
4134            hovered_region_ids: params.hovered_region_ids.clone(),
4135            clicked_region_ids: params.clicked_region_ids.clone(),
4136            refreshing: params.refreshing,
4137            appearance: params.appearance,
4138        }
4139    }
4140
4141    pub fn handle(&self) -> WeakViewHandle<V> {
4142        WeakViewHandle::new(self.window_id, self.view_id)
4143    }
4144
4145    pub fn window_id(&self) -> usize {
4146        self.window_id
4147    }
4148
4149    pub fn view_id(&self) -> usize {
4150        self.view_id
4151    }
4152
4153    pub fn mouse_state<Tag: 'static>(&self, region_id: usize) -> MouseState {
4154        let region_id = MouseRegionId::new::<Tag>(self.view_id, region_id);
4155        MouseState {
4156            hovered: self.hovered_region_ids.contains(&region_id),
4157            clicked: self.clicked_region_ids.as_ref().and_then(|(ids, button)| {
4158                if ids.contains(&region_id) {
4159                    Some(*button)
4160                } else {
4161                    None
4162                }
4163            }),
4164            accessed_hovered: false,
4165            accessed_clicked: false,
4166        }
4167    }
4168
4169    pub fn element_state<Tag: 'static, T: 'static>(
4170        &mut self,
4171        element_id: usize,
4172        initial: T,
4173    ) -> ElementStateHandle<T> {
4174        let id = ElementStateId {
4175            view_id: self.view_id(),
4176            element_id,
4177            tag: TypeId::of::<Tag>(),
4178        };
4179        self.element_states
4180            .entry(id)
4181            .or_insert_with(|| Box::new(initial));
4182        ElementStateHandle::new(id, self.frame_count, &self.ref_counts)
4183    }
4184
4185    pub fn default_element_state<Tag: 'static, T: 'static + Default>(
4186        &mut self,
4187        element_id: usize,
4188    ) -> ElementStateHandle<T> {
4189        self.element_state::<Tag, T>(element_id, T::default())
4190    }
4191}
4192
4193impl<V: View> Deref for RenderContext<'_, V> {
4194    type Target = AppContext;
4195
4196    fn deref(&self) -> &Self::Target {
4197        self.app
4198    }
4199}
4200
4201impl<V: View> DerefMut for RenderContext<'_, V> {
4202    fn deref_mut(&mut self) -> &mut Self::Target {
4203        self.app
4204    }
4205}
4206
4207impl<V: View> ReadModel for RenderContext<'_, V> {
4208    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
4209        self.app.read_model(handle)
4210    }
4211}
4212
4213impl<V: View> UpdateModel for RenderContext<'_, V> {
4214    fn update_model<T: Entity, O>(
4215        &mut self,
4216        handle: &ModelHandle<T>,
4217        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
4218    ) -> O {
4219        self.app.update_model(handle, update)
4220    }
4221}
4222
4223impl<V: View> ReadView for RenderContext<'_, V> {
4224    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
4225        self.app.read_view(handle)
4226    }
4227}
4228
4229impl<M> Deref for ViewContext<'_, M> {
4230    type Target = AppContext;
4231
4232    fn deref(&self) -> &Self::Target {
4233        self.app
4234    }
4235}
4236
4237impl<M> DerefMut for ViewContext<'_, M> {
4238    fn deref_mut(&mut self) -> &mut Self::Target {
4239        &mut self.app
4240    }
4241}
4242
4243impl<M> AsMut<AppContext> for ViewContext<'_, M> {
4244    fn as_mut(&mut self) -> &mut AppContext {
4245        self.app
4246    }
4247}
4248
4249impl<V> ReadModel for ViewContext<'_, V> {
4250    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
4251        self.app.read_model(handle)
4252    }
4253}
4254
4255impl<V> UpgradeModelHandle for ViewContext<'_, V> {
4256    fn upgrade_model_handle<T: Entity>(
4257        &self,
4258        handle: &WeakModelHandle<T>,
4259    ) -> Option<ModelHandle<T>> {
4260        self.app.upgrade_model_handle(handle)
4261    }
4262
4263    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
4264        self.app.model_handle_is_upgradable(handle)
4265    }
4266
4267    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
4268        self.app.upgrade_any_model_handle(handle)
4269    }
4270}
4271
4272impl<V> UpgradeViewHandle for ViewContext<'_, V> {
4273    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
4274        self.app.upgrade_view_handle(handle)
4275    }
4276
4277    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
4278        self.app.upgrade_any_view_handle(handle)
4279    }
4280}
4281
4282impl<V: View> UpgradeViewHandle for RenderContext<'_, V> {
4283    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
4284        self.app.upgrade_view_handle(handle)
4285    }
4286
4287    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
4288        self.app.upgrade_any_view_handle(handle)
4289    }
4290}
4291
4292impl<V: View> UpdateModel for ViewContext<'_, V> {
4293    fn update_model<T: Entity, O>(
4294        &mut self,
4295        handle: &ModelHandle<T>,
4296        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
4297    ) -> O {
4298        self.app.update_model(handle, update)
4299    }
4300}
4301
4302impl<V: View> ReadView for ViewContext<'_, V> {
4303    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
4304        self.app.read_view(handle)
4305    }
4306}
4307
4308impl<V: View> UpdateView for ViewContext<'_, V> {
4309    fn update_view<T, S>(
4310        &mut self,
4311        handle: &ViewHandle<T>,
4312        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
4313    ) -> S
4314    where
4315        T: View,
4316    {
4317        self.app.update_view(handle, update)
4318    }
4319}
4320
4321pub trait Handle<T> {
4322    type Weak: 'static;
4323    fn id(&self) -> usize;
4324    fn location(&self) -> EntityLocation;
4325    fn downgrade(&self) -> Self::Weak;
4326    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
4327    where
4328        Self: Sized;
4329}
4330
4331pub trait WeakHandle {
4332    fn id(&self) -> usize;
4333}
4334
4335#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
4336pub enum EntityLocation {
4337    Model(usize),
4338    View(usize, usize),
4339}
4340
4341pub struct ModelHandle<T: Entity> {
4342    any_handle: AnyModelHandle,
4343    model_type: PhantomData<T>,
4344}
4345
4346impl<T: Entity> Deref for ModelHandle<T> {
4347    type Target = AnyModelHandle;
4348
4349    fn deref(&self) -> &Self::Target {
4350        &self.any_handle
4351    }
4352}
4353
4354impl<T: Entity> ModelHandle<T> {
4355    fn new(model_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
4356        Self {
4357            any_handle: AnyModelHandle::new(model_id, TypeId::of::<T>(), ref_counts.clone()),
4358            model_type: PhantomData,
4359        }
4360    }
4361
4362    pub fn downgrade(&self) -> WeakModelHandle<T> {
4363        WeakModelHandle::new(self.model_id)
4364    }
4365
4366    pub fn id(&self) -> usize {
4367        self.model_id
4368    }
4369
4370    pub fn read<'a, C: ReadModel>(&self, cx: &'a C) -> &'a T {
4371        cx.read_model(self)
4372    }
4373
4374    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
4375    where
4376        C: ReadModelWith,
4377        F: FnOnce(&T, &AppContext) -> S,
4378    {
4379        let mut read = Some(read);
4380        cx.read_model_with(self, &mut |model, cx| {
4381            let read = read.take().unwrap();
4382            read(model, cx)
4383        })
4384    }
4385
4386    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
4387    where
4388        C: UpdateModel,
4389        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
4390    {
4391        let mut update = Some(update);
4392        cx.update_model(self, &mut |model, cx| {
4393            let update = update.take().unwrap();
4394            update(model, cx)
4395        })
4396    }
4397}
4398
4399impl<T: Entity> Clone for ModelHandle<T> {
4400    fn clone(&self) -> Self {
4401        Self::new(self.model_id, &self.ref_counts)
4402    }
4403}
4404
4405impl<T: Entity> PartialEq for ModelHandle<T> {
4406    fn eq(&self, other: &Self) -> bool {
4407        self.model_id == other.model_id
4408    }
4409}
4410
4411impl<T: Entity> Eq for ModelHandle<T> {}
4412
4413impl<T: Entity> PartialEq<WeakModelHandle<T>> for ModelHandle<T> {
4414    fn eq(&self, other: &WeakModelHandle<T>) -> bool {
4415        self.model_id == other.model_id
4416    }
4417}
4418
4419impl<T: Entity> Hash for ModelHandle<T> {
4420    fn hash<H: Hasher>(&self, state: &mut H) {
4421        self.model_id.hash(state);
4422    }
4423}
4424
4425impl<T: Entity> std::borrow::Borrow<usize> for ModelHandle<T> {
4426    fn borrow(&self) -> &usize {
4427        &self.model_id
4428    }
4429}
4430
4431impl<T: Entity> Debug for ModelHandle<T> {
4432    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
4433        f.debug_tuple(&format!("ModelHandle<{}>", type_name::<T>()))
4434            .field(&self.model_id)
4435            .finish()
4436    }
4437}
4438
4439unsafe impl<T: Entity> Send for ModelHandle<T> {}
4440unsafe impl<T: Entity> Sync for ModelHandle<T> {}
4441
4442impl<T: Entity> Handle<T> for ModelHandle<T> {
4443    type Weak = WeakModelHandle<T>;
4444
4445    fn id(&self) -> usize {
4446        self.model_id
4447    }
4448
4449    fn location(&self) -> EntityLocation {
4450        EntityLocation::Model(self.model_id)
4451    }
4452
4453    fn downgrade(&self) -> Self::Weak {
4454        self.downgrade()
4455    }
4456
4457    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
4458    where
4459        Self: Sized,
4460    {
4461        weak.upgrade(cx)
4462    }
4463}
4464
4465pub struct WeakModelHandle<T> {
4466    any_handle: AnyWeakModelHandle,
4467    model_type: PhantomData<T>,
4468}
4469
4470impl<T> WeakModelHandle<T> {
4471    pub fn into_any(self) -> AnyWeakModelHandle {
4472        self.any_handle
4473    }
4474}
4475
4476impl<T> Deref for WeakModelHandle<T> {
4477    type Target = AnyWeakModelHandle;
4478
4479    fn deref(&self) -> &Self::Target {
4480        &self.any_handle
4481    }
4482}
4483
4484impl<T> WeakHandle for WeakModelHandle<T> {
4485    fn id(&self) -> usize {
4486        self.model_id
4487    }
4488}
4489
4490unsafe impl<T> Send for WeakModelHandle<T> {}
4491unsafe impl<T> Sync for WeakModelHandle<T> {}
4492
4493impl<T: Entity> WeakModelHandle<T> {
4494    fn new(model_id: usize) -> Self {
4495        Self {
4496            any_handle: AnyWeakModelHandle {
4497                model_id,
4498                model_type: TypeId::of::<T>(),
4499            },
4500            model_type: PhantomData,
4501        }
4502    }
4503
4504    pub fn id(&self) -> usize {
4505        self.model_id
4506    }
4507
4508    pub fn is_upgradable(&self, cx: &impl UpgradeModelHandle) -> bool {
4509        cx.model_handle_is_upgradable(self)
4510    }
4511
4512    pub fn upgrade(&self, cx: &impl UpgradeModelHandle) -> Option<ModelHandle<T>> {
4513        cx.upgrade_model_handle(self)
4514    }
4515}
4516
4517impl<T> Hash for WeakModelHandle<T> {
4518    fn hash<H: Hasher>(&self, state: &mut H) {
4519        self.model_id.hash(state)
4520    }
4521}
4522
4523impl<T> PartialEq for WeakModelHandle<T> {
4524    fn eq(&self, other: &Self) -> bool {
4525        self.model_id == other.model_id
4526    }
4527}
4528
4529impl<T> Eq for WeakModelHandle<T> {}
4530
4531impl<T: Entity> PartialEq<ModelHandle<T>> for WeakModelHandle<T> {
4532    fn eq(&self, other: &ModelHandle<T>) -> bool {
4533        self.model_id == other.model_id
4534    }
4535}
4536
4537impl<T> Clone for WeakModelHandle<T> {
4538    fn clone(&self) -> Self {
4539        Self {
4540            any_handle: self.any_handle.clone(),
4541            model_type: PhantomData,
4542        }
4543    }
4544}
4545
4546impl<T> Copy for WeakModelHandle<T> {}
4547
4548#[repr(transparent)]
4549pub struct ViewHandle<T> {
4550    any_handle: AnyViewHandle,
4551    view_type: PhantomData<T>,
4552}
4553
4554impl<T> Deref for ViewHandle<T> {
4555    type Target = AnyViewHandle;
4556
4557    fn deref(&self) -> &Self::Target {
4558        &self.any_handle
4559    }
4560}
4561
4562impl<T: View> ViewHandle<T> {
4563    fn new(window_id: usize, view_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
4564        Self {
4565            any_handle: AnyViewHandle::new(
4566                window_id,
4567                view_id,
4568                TypeId::of::<T>(),
4569                ref_counts.clone(),
4570            ),
4571            view_type: PhantomData,
4572        }
4573    }
4574
4575    pub fn downgrade(&self) -> WeakViewHandle<T> {
4576        WeakViewHandle::new(self.window_id, self.view_id)
4577    }
4578
4579    pub fn into_any(self) -> AnyViewHandle {
4580        self.any_handle
4581    }
4582
4583    pub fn window_id(&self) -> usize {
4584        self.window_id
4585    }
4586
4587    pub fn id(&self) -> usize {
4588        self.view_id
4589    }
4590
4591    pub fn read<'a, C: ReadView>(&self, cx: &'a C) -> &'a T {
4592        cx.read_view(self)
4593    }
4594
4595    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
4596    where
4597        C: ReadViewWith,
4598        F: FnOnce(&T, &AppContext) -> S,
4599    {
4600        let mut read = Some(read);
4601        cx.read_view_with(self, &mut |view, cx| {
4602            let read = read.take().unwrap();
4603            read(view, cx)
4604        })
4605    }
4606
4607    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
4608    where
4609        C: UpdateView,
4610        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
4611    {
4612        let mut update = Some(update);
4613        cx.update_view(self, &mut |view, cx| {
4614            let update = update.take().unwrap();
4615            update(view, cx)
4616        })
4617    }
4618
4619    pub fn defer<C, F>(&self, cx: &mut C, update: F)
4620    where
4621        C: AsMut<AppContext>,
4622        F: 'static + FnOnce(&mut T, &mut ViewContext<T>),
4623    {
4624        let this = self.clone();
4625        cx.as_mut().defer(move |cx| {
4626            this.update(cx, |view, cx| update(view, cx));
4627        });
4628    }
4629
4630    pub fn is_focused(&self, cx: &AppContext) -> bool {
4631        cx.focused_view_id(self.window_id)
4632            .map_or(false, |focused_id| focused_id == self.view_id)
4633    }
4634}
4635
4636impl<T: View> Clone for ViewHandle<T> {
4637    fn clone(&self) -> Self {
4638        ViewHandle::new(self.window_id, self.view_id, &self.ref_counts)
4639    }
4640}
4641
4642impl<T> PartialEq for ViewHandle<T> {
4643    fn eq(&self, other: &Self) -> bool {
4644        self.window_id == other.window_id && self.view_id == other.view_id
4645    }
4646}
4647
4648impl<T> PartialEq<WeakViewHandle<T>> for ViewHandle<T> {
4649    fn eq(&self, other: &WeakViewHandle<T>) -> bool {
4650        self.window_id == other.window_id && self.view_id == other.view_id
4651    }
4652}
4653
4654impl<T> PartialEq<ViewHandle<T>> for WeakViewHandle<T> {
4655    fn eq(&self, other: &ViewHandle<T>) -> bool {
4656        self.window_id == other.window_id && self.view_id == other.view_id
4657    }
4658}
4659
4660impl<T> Eq for ViewHandle<T> {}
4661
4662impl<T> Hash for ViewHandle<T> {
4663    fn hash<H: Hasher>(&self, state: &mut H) {
4664        self.window_id.hash(state);
4665        self.view_id.hash(state);
4666    }
4667}
4668
4669impl<T> Debug for ViewHandle<T> {
4670    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
4671        f.debug_struct(&format!("ViewHandle<{}>", type_name::<T>()))
4672            .field("window_id", &self.window_id)
4673            .field("view_id", &self.view_id)
4674            .finish()
4675    }
4676}
4677
4678impl<T: View> Handle<T> for ViewHandle<T> {
4679    type Weak = WeakViewHandle<T>;
4680
4681    fn id(&self) -> usize {
4682        self.view_id
4683    }
4684
4685    fn location(&self) -> EntityLocation {
4686        EntityLocation::View(self.window_id, self.view_id)
4687    }
4688
4689    fn downgrade(&self) -> Self::Weak {
4690        self.downgrade()
4691    }
4692
4693    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
4694    where
4695        Self: Sized,
4696    {
4697        weak.upgrade(cx)
4698    }
4699}
4700
4701pub struct AnyViewHandle {
4702    window_id: usize,
4703    view_id: usize,
4704    view_type: TypeId,
4705    ref_counts: Arc<Mutex<RefCounts>>,
4706
4707    #[cfg(any(test, feature = "test-support"))]
4708    handle_id: usize,
4709}
4710
4711impl AnyViewHandle {
4712    fn new(
4713        window_id: usize,
4714        view_id: usize,
4715        view_type: TypeId,
4716        ref_counts: Arc<Mutex<RefCounts>>,
4717    ) -> Self {
4718        ref_counts.lock().inc_view(window_id, view_id);
4719
4720        #[cfg(any(test, feature = "test-support"))]
4721        let handle_id = ref_counts
4722            .lock()
4723            .leak_detector
4724            .lock()
4725            .handle_created(None, view_id);
4726
4727        Self {
4728            window_id,
4729            view_id,
4730            view_type,
4731            ref_counts,
4732            #[cfg(any(test, feature = "test-support"))]
4733            handle_id,
4734        }
4735    }
4736
4737    pub fn window_id(&self) -> usize {
4738        self.window_id
4739    }
4740
4741    pub fn id(&self) -> usize {
4742        self.view_id
4743    }
4744
4745    pub fn is<T: 'static>(&self) -> bool {
4746        TypeId::of::<T>() == self.view_type
4747    }
4748
4749    pub fn is_focused(&self, cx: &AppContext) -> bool {
4750        cx.focused_view_id(self.window_id)
4751            .map_or(false, |focused_id| focused_id == self.view_id)
4752    }
4753
4754    pub fn downcast<T: View>(self) -> Option<ViewHandle<T>> {
4755        if self.is::<T>() {
4756            Some(ViewHandle {
4757                any_handle: self,
4758                view_type: PhantomData,
4759            })
4760        } else {
4761            None
4762        }
4763    }
4764
4765    pub fn downcast_ref<T: View>(&self) -> Option<&ViewHandle<T>> {
4766        if self.is::<T>() {
4767            Some(unsafe { mem::transmute(self) })
4768        } else {
4769            None
4770        }
4771    }
4772
4773    pub fn downgrade(&self) -> AnyWeakViewHandle {
4774        AnyWeakViewHandle {
4775            window_id: self.window_id,
4776            view_id: self.view_id,
4777            view_type: self.view_type,
4778        }
4779    }
4780
4781    pub fn view_type(&self) -> TypeId {
4782        self.view_type
4783    }
4784
4785    pub fn debug_json(&self, cx: &AppContext) -> serde_json::Value {
4786        cx.views
4787            .get(&(self.window_id, self.view_id))
4788            .map_or_else(|| serde_json::Value::Null, |view| view.debug_json(cx))
4789    }
4790}
4791
4792impl Clone for AnyViewHandle {
4793    fn clone(&self) -> Self {
4794        Self::new(
4795            self.window_id,
4796            self.view_id,
4797            self.view_type,
4798            self.ref_counts.clone(),
4799        )
4800    }
4801}
4802
4803impl<T> PartialEq<ViewHandle<T>> for AnyViewHandle {
4804    fn eq(&self, other: &ViewHandle<T>) -> bool {
4805        self.window_id == other.window_id && self.view_id == other.view_id
4806    }
4807}
4808
4809impl Drop for AnyViewHandle {
4810    fn drop(&mut self) {
4811        self.ref_counts
4812            .lock()
4813            .dec_view(self.window_id, self.view_id);
4814        #[cfg(any(test, feature = "test-support"))]
4815        self.ref_counts
4816            .lock()
4817            .leak_detector
4818            .lock()
4819            .handle_dropped(self.view_id, self.handle_id);
4820    }
4821}
4822
4823pub struct AnyModelHandle {
4824    model_id: usize,
4825    model_type: TypeId,
4826    ref_counts: Arc<Mutex<RefCounts>>,
4827
4828    #[cfg(any(test, feature = "test-support"))]
4829    handle_id: usize,
4830}
4831
4832impl AnyModelHandle {
4833    fn new(model_id: usize, model_type: TypeId, ref_counts: Arc<Mutex<RefCounts>>) -> Self {
4834        ref_counts.lock().inc_model(model_id);
4835
4836        #[cfg(any(test, feature = "test-support"))]
4837        let handle_id = ref_counts
4838            .lock()
4839            .leak_detector
4840            .lock()
4841            .handle_created(None, model_id);
4842
4843        Self {
4844            model_id,
4845            model_type,
4846            ref_counts,
4847
4848            #[cfg(any(test, feature = "test-support"))]
4849            handle_id,
4850        }
4851    }
4852
4853    pub fn downcast<T: Entity>(self) -> Option<ModelHandle<T>> {
4854        if self.is::<T>() {
4855            Some(ModelHandle {
4856                any_handle: self,
4857                model_type: PhantomData,
4858            })
4859        } else {
4860            None
4861        }
4862    }
4863
4864    pub fn downgrade(&self) -> AnyWeakModelHandle {
4865        AnyWeakModelHandle {
4866            model_id: self.model_id,
4867            model_type: self.model_type,
4868        }
4869    }
4870
4871    pub fn is<T: Entity>(&self) -> bool {
4872        self.model_type == TypeId::of::<T>()
4873    }
4874
4875    pub fn model_type(&self) -> TypeId {
4876        self.model_type
4877    }
4878}
4879
4880impl Clone for AnyModelHandle {
4881    fn clone(&self) -> Self {
4882        Self::new(self.model_id, self.model_type, self.ref_counts.clone())
4883    }
4884}
4885
4886impl Drop for AnyModelHandle {
4887    fn drop(&mut self) {
4888        let mut ref_counts = self.ref_counts.lock();
4889        ref_counts.dec_model(self.model_id);
4890
4891        #[cfg(any(test, feature = "test-support"))]
4892        ref_counts
4893            .leak_detector
4894            .lock()
4895            .handle_dropped(self.model_id, self.handle_id);
4896    }
4897}
4898
4899#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy)]
4900pub struct AnyWeakModelHandle {
4901    model_id: usize,
4902    model_type: TypeId,
4903}
4904
4905impl AnyWeakModelHandle {
4906    pub fn upgrade(&self, cx: &impl UpgradeModelHandle) -> Option<AnyModelHandle> {
4907        cx.upgrade_any_model_handle(self)
4908    }
4909    pub fn model_type(&self) -> TypeId {
4910        self.model_type
4911    }
4912
4913    fn is<T: 'static>(&self) -> bool {
4914        TypeId::of::<T>() == self.model_type
4915    }
4916
4917    pub fn downcast<T: Entity>(self) -> Option<WeakModelHandle<T>> {
4918        if self.is::<T>() {
4919            let result = Some(WeakModelHandle {
4920                any_handle: self,
4921                model_type: PhantomData,
4922            });
4923
4924            result
4925        } else {
4926            None
4927        }
4928    }
4929}
4930
4931#[derive(Debug, Copy)]
4932pub struct WeakViewHandle<T> {
4933    any_handle: AnyWeakViewHandle,
4934    view_type: PhantomData<T>,
4935}
4936
4937impl<T> WeakHandle for WeakViewHandle<T> {
4938    fn id(&self) -> usize {
4939        self.view_id
4940    }
4941}
4942
4943impl<T: View> WeakViewHandle<T> {
4944    fn new(window_id: usize, view_id: usize) -> Self {
4945        Self {
4946            any_handle: AnyWeakViewHandle {
4947                window_id,
4948                view_id,
4949                view_type: TypeId::of::<T>(),
4950            },
4951            view_type: PhantomData,
4952        }
4953    }
4954
4955    pub fn id(&self) -> usize {
4956        self.view_id
4957    }
4958
4959    pub fn window_id(&self) -> usize {
4960        self.window_id
4961    }
4962
4963    pub fn into_any(self) -> AnyWeakViewHandle {
4964        self.any_handle
4965    }
4966
4967    pub fn upgrade(&self, cx: &impl UpgradeViewHandle) -> Option<ViewHandle<T>> {
4968        cx.upgrade_view_handle(self)
4969    }
4970}
4971
4972impl<T> Deref for WeakViewHandle<T> {
4973    type Target = AnyWeakViewHandle;
4974
4975    fn deref(&self) -> &Self::Target {
4976        &self.any_handle
4977    }
4978}
4979
4980impl<T> Clone for WeakViewHandle<T> {
4981    fn clone(&self) -> Self {
4982        Self {
4983            any_handle: self.any_handle.clone(),
4984            view_type: PhantomData,
4985        }
4986    }
4987}
4988
4989impl<T> PartialEq for WeakViewHandle<T> {
4990    fn eq(&self, other: &Self) -> bool {
4991        self.window_id == other.window_id && self.view_id == other.view_id
4992    }
4993}
4994
4995impl<T> Eq for WeakViewHandle<T> {}
4996
4997impl<T> Hash for WeakViewHandle<T> {
4998    fn hash<H: Hasher>(&self, state: &mut H) {
4999        self.any_handle.hash(state);
5000    }
5001}
5002
5003#[derive(Debug, Clone, Copy)]
5004pub struct AnyWeakViewHandle {
5005    window_id: usize,
5006    view_id: usize,
5007    view_type: TypeId,
5008}
5009
5010impl AnyWeakViewHandle {
5011    pub fn id(&self) -> usize {
5012        self.view_id
5013    }
5014
5015    pub fn upgrade(&self, cx: &impl UpgradeViewHandle) -> Option<AnyViewHandle> {
5016        cx.upgrade_any_view_handle(self)
5017    }
5018}
5019
5020impl Hash for AnyWeakViewHandle {
5021    fn hash<H: Hasher>(&self, state: &mut H) {
5022        self.window_id.hash(state);
5023        self.view_id.hash(state);
5024        self.view_type.hash(state);
5025    }
5026}
5027
5028#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
5029pub struct ElementStateId {
5030    view_id: usize,
5031    element_id: usize,
5032    tag: TypeId,
5033}
5034
5035pub struct ElementStateHandle<T> {
5036    value_type: PhantomData<T>,
5037    id: ElementStateId,
5038    ref_counts: Weak<Mutex<RefCounts>>,
5039}
5040
5041impl<T: 'static> ElementStateHandle<T> {
5042    fn new(id: ElementStateId, frame_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
5043        ref_counts.lock().inc_element_state(id, frame_id);
5044        Self {
5045            value_type: PhantomData,
5046            id,
5047            ref_counts: Arc::downgrade(ref_counts),
5048        }
5049    }
5050
5051    pub fn id(&self) -> ElementStateId {
5052        self.id
5053    }
5054
5055    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
5056        cx.element_states
5057            .get(&self.id)
5058            .unwrap()
5059            .downcast_ref()
5060            .unwrap()
5061    }
5062
5063    pub fn update<C, R>(&self, cx: &mut C, f: impl FnOnce(&mut T, &mut C) -> R) -> R
5064    where
5065        C: DerefMut<Target = AppContext>,
5066    {
5067        let mut element_state = cx.deref_mut().element_states.remove(&self.id).unwrap();
5068        let result = f(element_state.downcast_mut().unwrap(), cx);
5069        cx.deref_mut().element_states.insert(self.id, element_state);
5070        result
5071    }
5072}
5073
5074impl<T> Drop for ElementStateHandle<T> {
5075    fn drop(&mut self) {
5076        if let Some(ref_counts) = self.ref_counts.upgrade() {
5077            ref_counts.lock().dec_element_state(self.id);
5078        }
5079    }
5080}
5081
5082#[must_use]
5083pub enum Subscription {
5084    Subscription(callback_collection::Subscription<usize, SubscriptionCallback>),
5085    Observation(callback_collection::Subscription<usize, ObservationCallback>),
5086    GlobalSubscription(callback_collection::Subscription<TypeId, GlobalSubscriptionCallback>),
5087    GlobalObservation(callback_collection::Subscription<TypeId, GlobalObservationCallback>),
5088    FocusObservation(callback_collection::Subscription<usize, FocusObservationCallback>),
5089    WindowActivationObservation(callback_collection::Subscription<usize, WindowActivationCallback>),
5090    WindowFullscreenObservation(callback_collection::Subscription<usize, WindowFullscreenCallback>),
5091    WindowBoundsObservation(callback_collection::Subscription<usize, WindowBoundsCallback>),
5092    KeystrokeObservation(callback_collection::Subscription<usize, KeystrokeCallback>),
5093    ReleaseObservation(callback_collection::Subscription<usize, ReleaseObservationCallback>),
5094    ActionObservation(callback_collection::Subscription<(), ActionObservationCallback>),
5095    ActiveLabeledTasksObservation(
5096        callback_collection::Subscription<(), ActiveLabeledTasksCallback>,
5097    ),
5098}
5099
5100impl Subscription {
5101    pub fn id(&self) -> usize {
5102        match self {
5103            Subscription::Subscription(subscription) => subscription.id(),
5104            Subscription::Observation(subscription) => subscription.id(),
5105            Subscription::GlobalSubscription(subscription) => subscription.id(),
5106            Subscription::GlobalObservation(subscription) => subscription.id(),
5107            Subscription::FocusObservation(subscription) => subscription.id(),
5108            Subscription::WindowActivationObservation(subscription) => subscription.id(),
5109            Subscription::WindowFullscreenObservation(subscription) => subscription.id(),
5110            Subscription::WindowBoundsObservation(subscription) => subscription.id(),
5111            Subscription::KeystrokeObservation(subscription) => subscription.id(),
5112            Subscription::ReleaseObservation(subscription) => subscription.id(),
5113            Subscription::ActionObservation(subscription) => subscription.id(),
5114            Subscription::ActiveLabeledTasksObservation(subscription) => subscription.id(),
5115        }
5116    }
5117
5118    pub fn detach(&mut self) {
5119        match self {
5120            Subscription::Subscription(subscription) => subscription.detach(),
5121            Subscription::GlobalSubscription(subscription) => subscription.detach(),
5122            Subscription::Observation(subscription) => subscription.detach(),
5123            Subscription::GlobalObservation(subscription) => subscription.detach(),
5124            Subscription::FocusObservation(subscription) => subscription.detach(),
5125            Subscription::KeystrokeObservation(subscription) => subscription.detach(),
5126            Subscription::WindowActivationObservation(subscription) => subscription.detach(),
5127            Subscription::WindowFullscreenObservation(subscription) => subscription.detach(),
5128            Subscription::WindowBoundsObservation(subscription) => subscription.detach(),
5129            Subscription::ReleaseObservation(subscription) => subscription.detach(),
5130            Subscription::ActionObservation(subscription) => subscription.detach(),
5131            Subscription::ActiveLabeledTasksObservation(subscription) => subscription.detach(),
5132        }
5133    }
5134}
5135
5136#[cfg(test)]
5137mod tests {
5138    use super::*;
5139    use crate::{actions, elements::*, impl_actions, MouseButton, MouseButtonEvent};
5140    use itertools::Itertools;
5141    use postage::{sink::Sink, stream::Stream};
5142    use serde::Deserialize;
5143    use smol::future::poll_once;
5144    use std::{
5145        cell::Cell,
5146        sync::atomic::{AtomicBool, AtomicUsize, Ordering::SeqCst},
5147    };
5148
5149    #[crate::test(self)]
5150    fn test_model_handles(cx: &mut AppContext) {
5151        struct Model {
5152            other: Option<ModelHandle<Model>>,
5153            events: Vec<String>,
5154        }
5155
5156        impl Entity for Model {
5157            type Event = usize;
5158        }
5159
5160        impl Model {
5161            fn new(other: Option<ModelHandle<Self>>, cx: &mut ModelContext<Self>) -> Self {
5162                if let Some(other) = other.as_ref() {
5163                    cx.observe(other, |me, _, _| {
5164                        me.events.push("notified".into());
5165                    })
5166                    .detach();
5167                    cx.subscribe(other, |me, _, event, _| {
5168                        me.events.push(format!("observed event {}", event));
5169                    })
5170                    .detach();
5171                }
5172
5173                Self {
5174                    other,
5175                    events: Vec::new(),
5176                }
5177            }
5178        }
5179
5180        let handle_1 = cx.add_model(|cx| Model::new(None, cx));
5181        let handle_2 = cx.add_model(|cx| Model::new(Some(handle_1.clone()), cx));
5182        assert_eq!(cx.models.len(), 2);
5183
5184        handle_1.update(cx, |model, cx| {
5185            model.events.push("updated".into());
5186            cx.emit(1);
5187            cx.notify();
5188            cx.emit(2);
5189        });
5190        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
5191        assert_eq!(
5192            handle_2.read(cx).events,
5193            vec![
5194                "observed event 1".to_string(),
5195                "notified".to_string(),
5196                "observed event 2".to_string(),
5197            ]
5198        );
5199
5200        handle_2.update(cx, |model, _| {
5201            drop(handle_1);
5202            model.other.take();
5203        });
5204
5205        assert_eq!(cx.models.len(), 1);
5206        assert!(cx.subscriptions.is_empty());
5207        assert!(cx.observations.is_empty());
5208    }
5209
5210    #[crate::test(self)]
5211    fn test_model_events(cx: &mut AppContext) {
5212        #[derive(Default)]
5213        struct Model {
5214            events: Vec<usize>,
5215        }
5216
5217        impl Entity for Model {
5218            type Event = usize;
5219        }
5220
5221        let handle_1 = cx.add_model(|_| Model::default());
5222        let handle_2 = cx.add_model(|_| Model::default());
5223
5224        handle_1.update(cx, |_, cx| {
5225            cx.subscribe(&handle_2, move |model: &mut Model, emitter, event, cx| {
5226                model.events.push(*event);
5227
5228                cx.subscribe(&emitter, |model, _, event, _| {
5229                    model.events.push(*event * 2);
5230                })
5231                .detach();
5232            })
5233            .detach();
5234        });
5235
5236        handle_2.update(cx, |_, c| c.emit(7));
5237        assert_eq!(handle_1.read(cx).events, vec![7]);
5238
5239        handle_2.update(cx, |_, c| c.emit(5));
5240        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10]);
5241    }
5242
5243    #[crate::test(self)]
5244    fn test_model_emit_before_subscribe_in_same_update_cycle(cx: &mut AppContext) {
5245        #[derive(Default)]
5246        struct Model;
5247
5248        impl Entity for Model {
5249            type Event = ();
5250        }
5251
5252        let events = Rc::new(RefCell::new(Vec::new()));
5253        cx.add_model(|cx| {
5254            drop(cx.subscribe(&cx.handle(), {
5255                let events = events.clone();
5256                move |_, _, _, _| events.borrow_mut().push("dropped before flush")
5257            }));
5258            cx.subscribe(&cx.handle(), {
5259                let events = events.clone();
5260                move |_, _, _, _| events.borrow_mut().push("before emit")
5261            })
5262            .detach();
5263            cx.emit(());
5264            cx.subscribe(&cx.handle(), {
5265                let events = events.clone();
5266                move |_, _, _, _| events.borrow_mut().push("after emit")
5267            })
5268            .detach();
5269            Model
5270        });
5271        assert_eq!(*events.borrow(), ["before emit"]);
5272    }
5273
5274    #[crate::test(self)]
5275    fn test_observe_and_notify_from_model(cx: &mut AppContext) {
5276        #[derive(Default)]
5277        struct Model {
5278            count: usize,
5279            events: Vec<usize>,
5280        }
5281
5282        impl Entity for Model {
5283            type Event = ();
5284        }
5285
5286        let handle_1 = cx.add_model(|_| Model::default());
5287        let handle_2 = cx.add_model(|_| Model::default());
5288
5289        handle_1.update(cx, |_, c| {
5290            c.observe(&handle_2, move |model, observed, c| {
5291                model.events.push(observed.read(c).count);
5292                c.observe(&observed, |model, observed, c| {
5293                    model.events.push(observed.read(c).count * 2);
5294                })
5295                .detach();
5296            })
5297            .detach();
5298        });
5299
5300        handle_2.update(cx, |model, c| {
5301            model.count = 7;
5302            c.notify()
5303        });
5304        assert_eq!(handle_1.read(cx).events, vec![7]);
5305
5306        handle_2.update(cx, |model, c| {
5307            model.count = 5;
5308            c.notify()
5309        });
5310        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10])
5311    }
5312
5313    #[crate::test(self)]
5314    fn test_model_notify_before_observe_in_same_update_cycle(cx: &mut AppContext) {
5315        #[derive(Default)]
5316        struct Model;
5317
5318        impl Entity for Model {
5319            type Event = ();
5320        }
5321
5322        let events = Rc::new(RefCell::new(Vec::new()));
5323        cx.add_model(|cx| {
5324            drop(cx.observe(&cx.handle(), {
5325                let events = events.clone();
5326                move |_, _, _| events.borrow_mut().push("dropped before flush")
5327            }));
5328            cx.observe(&cx.handle(), {
5329                let events = events.clone();
5330                move |_, _, _| events.borrow_mut().push("before notify")
5331            })
5332            .detach();
5333            cx.notify();
5334            cx.observe(&cx.handle(), {
5335                let events = events.clone();
5336                move |_, _, _| events.borrow_mut().push("after notify")
5337            })
5338            .detach();
5339            Model
5340        });
5341        assert_eq!(*events.borrow(), ["before notify"]);
5342    }
5343
5344    #[crate::test(self)]
5345    fn test_defer_and_after_window_update(cx: &mut AppContext) {
5346        struct View {
5347            render_count: usize,
5348        }
5349
5350        impl Entity for View {
5351            type Event = usize;
5352        }
5353
5354        impl super::View for View {
5355            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
5356                post_inc(&mut self.render_count);
5357                Empty::new().boxed()
5358            }
5359
5360            fn ui_name() -> &'static str {
5361                "View"
5362            }
5363        }
5364
5365        let (_, view) = cx.add_window(Default::default(), |_| View { render_count: 0 });
5366        let called_defer = Rc::new(AtomicBool::new(false));
5367        let called_after_window_update = Rc::new(AtomicBool::new(false));
5368
5369        view.update(cx, |this, cx| {
5370            assert_eq!(this.render_count, 1);
5371            cx.defer({
5372                let called_defer = called_defer.clone();
5373                move |this, _| {
5374                    assert_eq!(this.render_count, 1);
5375                    called_defer.store(true, SeqCst);
5376                }
5377            });
5378            cx.after_window_update({
5379                let called_after_window_update = called_after_window_update.clone();
5380                move |this, cx| {
5381                    assert_eq!(this.render_count, 2);
5382                    called_after_window_update.store(true, SeqCst);
5383                    cx.notify();
5384                }
5385            });
5386            assert!(!called_defer.load(SeqCst));
5387            assert!(!called_after_window_update.load(SeqCst));
5388            cx.notify();
5389        });
5390
5391        assert!(called_defer.load(SeqCst));
5392        assert!(called_after_window_update.load(SeqCst));
5393        assert_eq!(view.read(cx).render_count, 3);
5394    }
5395
5396    #[crate::test(self)]
5397    fn test_view_handles(cx: &mut AppContext) {
5398        struct View {
5399            other: Option<ViewHandle<View>>,
5400            events: Vec<String>,
5401        }
5402
5403        impl Entity for View {
5404            type Event = usize;
5405        }
5406
5407        impl super::View for View {
5408            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
5409                Empty::new().boxed()
5410            }
5411
5412            fn ui_name() -> &'static str {
5413                "View"
5414            }
5415        }
5416
5417        impl View {
5418            fn new(other: Option<ViewHandle<View>>, cx: &mut ViewContext<Self>) -> Self {
5419                if let Some(other) = other.as_ref() {
5420                    cx.subscribe(other, |me, _, event, _| {
5421                        me.events.push(format!("observed event {}", event));
5422                    })
5423                    .detach();
5424                }
5425                Self {
5426                    other,
5427                    events: Vec::new(),
5428                }
5429            }
5430        }
5431
5432        let (_, root_view) = cx.add_window(Default::default(), |cx| View::new(None, cx));
5433        let handle_1 = cx.add_view(&root_view, |cx| View::new(None, cx));
5434        let handle_2 = cx.add_view(&root_view, |cx| View::new(Some(handle_1.clone()), cx));
5435        assert_eq!(cx.views.len(), 3);
5436
5437        handle_1.update(cx, |view, cx| {
5438            view.events.push("updated".into());
5439            cx.emit(1);
5440            cx.emit(2);
5441        });
5442        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
5443        assert_eq!(
5444            handle_2.read(cx).events,
5445            vec![
5446                "observed event 1".to_string(),
5447                "observed event 2".to_string(),
5448            ]
5449        );
5450
5451        handle_2.update(cx, |view, _| {
5452            drop(handle_1);
5453            view.other.take();
5454        });
5455
5456        assert_eq!(cx.views.len(), 2);
5457        assert!(cx.subscriptions.is_empty());
5458        assert!(cx.observations.is_empty());
5459    }
5460
5461    #[crate::test(self)]
5462    fn test_add_window(cx: &mut AppContext) {
5463        struct View {
5464            mouse_down_count: Arc<AtomicUsize>,
5465        }
5466
5467        impl Entity for View {
5468            type Event = ();
5469        }
5470
5471        impl super::View for View {
5472            fn render(&mut self, cx: &mut RenderContext<Self>) -> ElementBox {
5473                enum Handler {}
5474                let mouse_down_count = self.mouse_down_count.clone();
5475                MouseEventHandler::<Handler>::new(0, cx, |_, _| Empty::new().boxed())
5476                    .on_down(MouseButton::Left, move |_, _| {
5477                        mouse_down_count.fetch_add(1, SeqCst);
5478                    })
5479                    .boxed()
5480            }
5481
5482            fn ui_name() -> &'static str {
5483                "View"
5484            }
5485        }
5486
5487        let mouse_down_count = Arc::new(AtomicUsize::new(0));
5488        let (window_id, _) = cx.add_window(Default::default(), |_| View {
5489            mouse_down_count: mouse_down_count.clone(),
5490        });
5491        let presenter = cx.presenters_and_platform_windows[&window_id].0.clone();
5492        // Ensure window's root element is in a valid lifecycle state.
5493        presenter.borrow_mut().dispatch_event(
5494            Event::MouseDown(MouseButtonEvent {
5495                position: Default::default(),
5496                button: MouseButton::Left,
5497                modifiers: Default::default(),
5498                click_count: 1,
5499            }),
5500            false,
5501            cx,
5502        );
5503        assert_eq!(mouse_down_count.load(SeqCst), 1);
5504    }
5505
5506    #[crate::test(self)]
5507    fn test_entity_release_hooks(cx: &mut AppContext) {
5508        struct Model {
5509            released: Rc<Cell<bool>>,
5510        }
5511
5512        struct View {
5513            released: Rc<Cell<bool>>,
5514        }
5515
5516        impl Entity for Model {
5517            type Event = ();
5518
5519            fn release(&mut self, _: &mut AppContext) {
5520                self.released.set(true);
5521            }
5522        }
5523
5524        impl Entity for View {
5525            type Event = ();
5526
5527            fn release(&mut self, _: &mut AppContext) {
5528                self.released.set(true);
5529            }
5530        }
5531
5532        impl super::View for View {
5533            fn ui_name() -> &'static str {
5534                "View"
5535            }
5536
5537            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
5538                Empty::new().boxed()
5539            }
5540        }
5541
5542        let model_released = Rc::new(Cell::new(false));
5543        let model_release_observed = Rc::new(Cell::new(false));
5544        let view_released = Rc::new(Cell::new(false));
5545        let view_release_observed = Rc::new(Cell::new(false));
5546
5547        let model = cx.add_model(|_| Model {
5548            released: model_released.clone(),
5549        });
5550        let (window_id, view) = cx.add_window(Default::default(), |_| View {
5551            released: view_released.clone(),
5552        });
5553        assert!(!model_released.get());
5554        assert!(!view_released.get());
5555
5556        cx.observe_release(&model, {
5557            let model_release_observed = model_release_observed.clone();
5558            move |_, _| model_release_observed.set(true)
5559        })
5560        .detach();
5561        cx.observe_release(&view, {
5562            let view_release_observed = view_release_observed.clone();
5563            move |_, _| view_release_observed.set(true)
5564        })
5565        .detach();
5566
5567        cx.update(move |_| {
5568            drop(model);
5569        });
5570        assert!(model_released.get());
5571        assert!(model_release_observed.get());
5572
5573        drop(view);
5574        cx.remove_window(window_id);
5575        assert!(view_released.get());
5576        assert!(view_release_observed.get());
5577    }
5578
5579    #[crate::test(self)]
5580    fn test_view_events(cx: &mut AppContext) {
5581        struct Model;
5582
5583        impl Entity for Model {
5584            type Event = String;
5585        }
5586
5587        let (_, handle_1) = cx.add_window(Default::default(), |_| TestView::default());
5588        let handle_2 = cx.add_view(&handle_1, |_| TestView::default());
5589        let handle_3 = cx.add_model(|_| Model);
5590
5591        handle_1.update(cx, |_, cx| {
5592            cx.subscribe(&handle_2, move |me, emitter, event, cx| {
5593                me.events.push(event.clone());
5594
5595                cx.subscribe(&emitter, |me, _, event, _| {
5596                    me.events.push(format!("{event} from inner"));
5597                })
5598                .detach();
5599            })
5600            .detach();
5601
5602            cx.subscribe(&handle_3, |me, _, event, _| {
5603                me.events.push(event.clone());
5604            })
5605            .detach();
5606        });
5607
5608        handle_2.update(cx, |_, c| c.emit("7".into()));
5609        assert_eq!(handle_1.read(cx).events, vec!["7"]);
5610
5611        handle_2.update(cx, |_, c| c.emit("5".into()));
5612        assert_eq!(handle_1.read(cx).events, vec!["7", "5", "5 from inner"]);
5613
5614        handle_3.update(cx, |_, c| c.emit("9".into()));
5615        assert_eq!(
5616            handle_1.read(cx).events,
5617            vec!["7", "5", "5 from inner", "9"]
5618        );
5619    }
5620
5621    #[crate::test(self)]
5622    fn test_global_events(cx: &mut AppContext) {
5623        #[derive(Clone, Debug, Eq, PartialEq)]
5624        struct GlobalEvent(u64);
5625
5626        let events = Rc::new(RefCell::new(Vec::new()));
5627        let first_subscription;
5628        let second_subscription;
5629
5630        {
5631            let events = events.clone();
5632            first_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
5633                events.borrow_mut().push(("First", e.clone()));
5634            });
5635        }
5636
5637        {
5638            let events = events.clone();
5639            second_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
5640                events.borrow_mut().push(("Second", e.clone()));
5641            });
5642        }
5643
5644        cx.update(|cx| {
5645            cx.emit_global(GlobalEvent(1));
5646            cx.emit_global(GlobalEvent(2));
5647        });
5648
5649        drop(first_subscription);
5650
5651        cx.update(|cx| {
5652            cx.emit_global(GlobalEvent(3));
5653        });
5654
5655        drop(second_subscription);
5656
5657        cx.update(|cx| {
5658            cx.emit_global(GlobalEvent(4));
5659        });
5660
5661        assert_eq!(
5662            &*events.borrow(),
5663            &[
5664                ("First", GlobalEvent(1)),
5665                ("Second", GlobalEvent(1)),
5666                ("First", GlobalEvent(2)),
5667                ("Second", GlobalEvent(2)),
5668                ("Second", GlobalEvent(3)),
5669            ]
5670        );
5671    }
5672
5673    #[crate::test(self)]
5674    fn test_global_events_emitted_before_subscription_in_same_update_cycle(cx: &mut AppContext) {
5675        let events = Rc::new(RefCell::new(Vec::new()));
5676        cx.update(|cx| {
5677            {
5678                let events = events.clone();
5679                drop(cx.subscribe_global(move |_: &(), _| {
5680                    events.borrow_mut().push("dropped before emit");
5681                }));
5682            }
5683
5684            {
5685                let events = events.clone();
5686                cx.subscribe_global(move |_: &(), _| {
5687                    events.borrow_mut().push("before emit");
5688                })
5689                .detach();
5690            }
5691
5692            cx.emit_global(());
5693
5694            {
5695                let events = events.clone();
5696                cx.subscribe_global(move |_: &(), _| {
5697                    events.borrow_mut().push("after emit");
5698                })
5699                .detach();
5700            }
5701        });
5702
5703        assert_eq!(*events.borrow(), ["before emit"]);
5704    }
5705
5706    #[crate::test(self)]
5707    fn test_global_nested_events(cx: &mut AppContext) {
5708        #[derive(Clone, Debug, Eq, PartialEq)]
5709        struct GlobalEvent(u64);
5710
5711        let events = Rc::new(RefCell::new(Vec::new()));
5712
5713        {
5714            let events = events.clone();
5715            cx.subscribe_global(move |e: &GlobalEvent, cx| {
5716                events.borrow_mut().push(("Outer", e.clone()));
5717
5718                if e.0 == 1 {
5719                    let events = events.clone();
5720                    cx.subscribe_global(move |e: &GlobalEvent, _| {
5721                        events.borrow_mut().push(("Inner", e.clone()));
5722                    })
5723                    .detach();
5724                }
5725            })
5726            .detach();
5727        }
5728
5729        cx.update(|cx| {
5730            cx.emit_global(GlobalEvent(1));
5731            cx.emit_global(GlobalEvent(2));
5732            cx.emit_global(GlobalEvent(3));
5733        });
5734        cx.update(|cx| {
5735            cx.emit_global(GlobalEvent(4));
5736        });
5737
5738        assert_eq!(
5739            &*events.borrow(),
5740            &[
5741                ("Outer", GlobalEvent(1)),
5742                ("Outer", GlobalEvent(2)),
5743                ("Outer", GlobalEvent(3)),
5744                ("Outer", GlobalEvent(4)),
5745                ("Inner", GlobalEvent(4)),
5746            ]
5747        );
5748    }
5749
5750    #[crate::test(self)]
5751    fn test_global(cx: &mut AppContext) {
5752        type Global = usize;
5753
5754        let observation_count = Rc::new(RefCell::new(0));
5755        let subscription = cx.observe_global::<Global, _>({
5756            let observation_count = observation_count.clone();
5757            move |_| {
5758                *observation_count.borrow_mut() += 1;
5759            }
5760        });
5761
5762        assert!(!cx.has_global::<Global>());
5763        assert_eq!(cx.default_global::<Global>(), &0);
5764        assert_eq!(*observation_count.borrow(), 1);
5765        assert!(cx.has_global::<Global>());
5766        assert_eq!(
5767            cx.update_global::<Global, _, _>(|global, _| {
5768                *global = 1;
5769                "Update Result"
5770            }),
5771            "Update Result"
5772        );
5773        assert_eq!(*observation_count.borrow(), 2);
5774        assert_eq!(cx.global::<Global>(), &1);
5775
5776        drop(subscription);
5777        cx.update_global::<Global, _, _>(|global, _| {
5778            *global = 2;
5779        });
5780        assert_eq!(*observation_count.borrow(), 2);
5781
5782        type OtherGlobal = f32;
5783
5784        let observation_count = Rc::new(RefCell::new(0));
5785        cx.observe_global::<OtherGlobal, _>({
5786            let observation_count = observation_count.clone();
5787            move |_| {
5788                *observation_count.borrow_mut() += 1;
5789            }
5790        })
5791        .detach();
5792
5793        assert_eq!(
5794            cx.update_default_global::<OtherGlobal, _, _>(|global, _| {
5795                assert_eq!(global, &0.0);
5796                *global = 2.0;
5797                "Default update result"
5798            }),
5799            "Default update result"
5800        );
5801        assert_eq!(cx.global::<OtherGlobal>(), &2.0);
5802        assert_eq!(*observation_count.borrow(), 1);
5803    }
5804
5805    #[crate::test(self)]
5806    fn test_dropping_subscribers(cx: &mut AppContext) {
5807        struct Model;
5808
5809        impl Entity for Model {
5810            type Event = ();
5811        }
5812
5813        let (_, root_view) = cx.add_window(Default::default(), |_| TestView::default());
5814        let observing_view = cx.add_view(&root_view, |_| TestView::default());
5815        let emitting_view = cx.add_view(&root_view, |_| TestView::default());
5816        let observing_model = cx.add_model(|_| Model);
5817        let observed_model = cx.add_model(|_| Model);
5818
5819        observing_view.update(cx, |_, cx| {
5820            cx.subscribe(&emitting_view, |_, _, _, _| {}).detach();
5821            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
5822        });
5823        observing_model.update(cx, |_, cx| {
5824            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
5825        });
5826
5827        cx.update(|_| {
5828            drop(observing_view);
5829            drop(observing_model);
5830        });
5831
5832        emitting_view.update(cx, |_, cx| cx.emit(Default::default()));
5833        observed_model.update(cx, |_, cx| cx.emit(()));
5834    }
5835
5836    #[crate::test(self)]
5837    fn test_view_emit_before_subscribe_in_same_update_cycle(cx: &mut AppContext) {
5838        let (_, view) = cx.add_window::<TestView, _>(Default::default(), |cx| {
5839            drop(cx.subscribe(&cx.handle(), {
5840                move |this, _, _, _| this.events.push("dropped before flush".into())
5841            }));
5842            cx.subscribe(&cx.handle(), {
5843                move |this, _, _, _| this.events.push("before emit".into())
5844            })
5845            .detach();
5846            cx.emit("the event".into());
5847            cx.subscribe(&cx.handle(), {
5848                move |this, _, _, _| this.events.push("after emit".into())
5849            })
5850            .detach();
5851            TestView { events: Vec::new() }
5852        });
5853
5854        assert_eq!(view.read(cx).events, ["before emit"]);
5855    }
5856
5857    #[crate::test(self)]
5858    fn test_observe_and_notify_from_view(cx: &mut AppContext) {
5859        #[derive(Default)]
5860        struct Model {
5861            state: String,
5862        }
5863
5864        impl Entity for Model {
5865            type Event = ();
5866        }
5867
5868        let (_, view) = cx.add_window(Default::default(), |_| TestView::default());
5869        let model = cx.add_model(|_| Model {
5870            state: "old-state".into(),
5871        });
5872
5873        view.update(cx, |_, c| {
5874            c.observe(&model, |me, observed, c| {
5875                me.events.push(observed.read(c).state.clone())
5876            })
5877            .detach();
5878        });
5879
5880        model.update(cx, |model, cx| {
5881            model.state = "new-state".into();
5882            cx.notify();
5883        });
5884        assert_eq!(view.read(cx).events, vec!["new-state"]);
5885    }
5886
5887    #[crate::test(self)]
5888    fn test_view_notify_before_observe_in_same_update_cycle(cx: &mut AppContext) {
5889        let (_, view) = cx.add_window::<TestView, _>(Default::default(), |cx| {
5890            drop(cx.observe(&cx.handle(), {
5891                move |this, _, _| this.events.push("dropped before flush".into())
5892            }));
5893            cx.observe(&cx.handle(), {
5894                move |this, _, _| this.events.push("before notify".into())
5895            })
5896            .detach();
5897            cx.notify();
5898            cx.observe(&cx.handle(), {
5899                move |this, _, _| this.events.push("after notify".into())
5900            })
5901            .detach();
5902            TestView { events: Vec::new() }
5903        });
5904
5905        assert_eq!(view.read(cx).events, ["before notify"]);
5906    }
5907
5908    #[crate::test(self)]
5909    fn test_notify_and_drop_observe_subscription_in_same_update_cycle(cx: &mut AppContext) {
5910        struct Model;
5911        impl Entity for Model {
5912            type Event = ();
5913        }
5914
5915        let model = cx.add_model(|_| Model);
5916        let (_, view) = cx.add_window(Default::default(), |_| TestView::default());
5917
5918        view.update(cx, |_, cx| {
5919            model.update(cx, |_, cx| cx.notify());
5920            drop(cx.observe(&model, move |this, _, _| {
5921                this.events.push("model notified".into());
5922            }));
5923            model.update(cx, |_, cx| cx.notify());
5924        });
5925
5926        for _ in 0..3 {
5927            model.update(cx, |_, cx| cx.notify());
5928        }
5929
5930        assert_eq!(view.read(cx).events, Vec::<String>::new());
5931    }
5932
5933    #[crate::test(self)]
5934    fn test_dropping_observers(cx: &mut AppContext) {
5935        struct Model;
5936
5937        impl Entity for Model {
5938            type Event = ();
5939        }
5940
5941        let (_, root_view) = cx.add_window(Default::default(), |_| TestView::default());
5942        let observing_view = cx.add_view(&root_view, |_| TestView::default());
5943        let observing_model = cx.add_model(|_| Model);
5944        let observed_model = cx.add_model(|_| Model);
5945
5946        observing_view.update(cx, |_, cx| {
5947            cx.observe(&observed_model, |_, _, _| {}).detach();
5948        });
5949        observing_model.update(cx, |_, cx| {
5950            cx.observe(&observed_model, |_, _, _| {}).detach();
5951        });
5952
5953        cx.update(|_| {
5954            drop(observing_view);
5955            drop(observing_model);
5956        });
5957
5958        observed_model.update(cx, |_, cx| cx.notify());
5959    }
5960
5961    #[crate::test(self)]
5962    fn test_dropping_subscriptions_during_callback(cx: &mut AppContext) {
5963        struct Model;
5964
5965        impl Entity for Model {
5966            type Event = u64;
5967        }
5968
5969        // Events
5970        let observing_model = cx.add_model(|_| Model);
5971        let observed_model = cx.add_model(|_| Model);
5972
5973        let events = Rc::new(RefCell::new(Vec::new()));
5974
5975        observing_model.update(cx, |_, cx| {
5976            let events = events.clone();
5977            let subscription = Rc::new(RefCell::new(None));
5978            *subscription.borrow_mut() = Some(cx.subscribe(&observed_model, {
5979                let subscription = subscription.clone();
5980                move |_, _, e, _| {
5981                    subscription.borrow_mut().take();
5982                    events.borrow_mut().push(*e);
5983                }
5984            }));
5985        });
5986
5987        observed_model.update(cx, |_, cx| {
5988            cx.emit(1);
5989            cx.emit(2);
5990        });
5991
5992        assert_eq!(*events.borrow(), [1]);
5993
5994        // Global Events
5995        #[derive(Clone, Debug, Eq, PartialEq)]
5996        struct GlobalEvent(u64);
5997
5998        let events = Rc::new(RefCell::new(Vec::new()));
5999
6000        {
6001            let events = events.clone();
6002            let subscription = Rc::new(RefCell::new(None));
6003            *subscription.borrow_mut() = Some(cx.subscribe_global({
6004                let subscription = subscription.clone();
6005                move |e: &GlobalEvent, _| {
6006                    subscription.borrow_mut().take();
6007                    events.borrow_mut().push(e.clone());
6008                }
6009            }));
6010        }
6011
6012        cx.update(|cx| {
6013            cx.emit_global(GlobalEvent(1));
6014            cx.emit_global(GlobalEvent(2));
6015        });
6016
6017        assert_eq!(*events.borrow(), [GlobalEvent(1)]);
6018
6019        // Model Observation
6020        let observing_model = cx.add_model(|_| Model);
6021        let observed_model = cx.add_model(|_| Model);
6022
6023        let observation_count = Rc::new(RefCell::new(0));
6024
6025        observing_model.update(cx, |_, cx| {
6026            let observation_count = observation_count.clone();
6027            let subscription = Rc::new(RefCell::new(None));
6028            *subscription.borrow_mut() = Some(cx.observe(&observed_model, {
6029                let subscription = subscription.clone();
6030                move |_, _, _| {
6031                    subscription.borrow_mut().take();
6032                    *observation_count.borrow_mut() += 1;
6033                }
6034            }));
6035        });
6036
6037        observed_model.update(cx, |_, cx| {
6038            cx.notify();
6039        });
6040
6041        observed_model.update(cx, |_, cx| {
6042            cx.notify();
6043        });
6044
6045        assert_eq!(*observation_count.borrow(), 1);
6046
6047        // View Observation
6048        struct View;
6049
6050        impl Entity for View {
6051            type Event = ();
6052        }
6053
6054        impl super::View for View {
6055            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6056                Empty::new().boxed()
6057            }
6058
6059            fn ui_name() -> &'static str {
6060                "View"
6061            }
6062        }
6063
6064        let (_, root_view) = cx.add_window(Default::default(), |_| View);
6065        let observing_view = cx.add_view(&root_view, |_| View);
6066        let observed_view = cx.add_view(&root_view, |_| View);
6067
6068        let observation_count = Rc::new(RefCell::new(0));
6069        observing_view.update(cx, |_, cx| {
6070            let observation_count = observation_count.clone();
6071            let subscription = Rc::new(RefCell::new(None));
6072            *subscription.borrow_mut() = Some(cx.observe(&observed_view, {
6073                let subscription = subscription.clone();
6074                move |_, _, _| {
6075                    subscription.borrow_mut().take();
6076                    *observation_count.borrow_mut() += 1;
6077                }
6078            }));
6079        });
6080
6081        observed_view.update(cx, |_, cx| {
6082            cx.notify();
6083        });
6084
6085        observed_view.update(cx, |_, cx| {
6086            cx.notify();
6087        });
6088
6089        assert_eq!(*observation_count.borrow(), 1);
6090
6091        // Global Observation
6092        let observation_count = Rc::new(RefCell::new(0));
6093        let subscription = Rc::new(RefCell::new(None));
6094        *subscription.borrow_mut() = Some(cx.observe_global::<(), _>({
6095            let observation_count = observation_count.clone();
6096            let subscription = subscription.clone();
6097            move |_| {
6098                subscription.borrow_mut().take();
6099                *observation_count.borrow_mut() += 1;
6100            }
6101        }));
6102
6103        cx.default_global::<()>();
6104        cx.set_global(());
6105        assert_eq!(*observation_count.borrow(), 1);
6106    }
6107
6108    #[crate::test(self)]
6109    fn test_focus(cx: &mut AppContext) {
6110        struct View {
6111            name: String,
6112            events: Arc<Mutex<Vec<String>>>,
6113        }
6114
6115        impl Entity for View {
6116            type Event = ();
6117        }
6118
6119        impl super::View for View {
6120            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6121                Empty::new().boxed()
6122            }
6123
6124            fn ui_name() -> &'static str {
6125                "View"
6126            }
6127
6128            fn focus_in(&mut self, focused: AnyViewHandle, cx: &mut ViewContext<Self>) {
6129                if cx.handle().id() == focused.id() {
6130                    self.events.lock().push(format!("{} focused", &self.name));
6131                }
6132            }
6133
6134            fn focus_out(&mut self, blurred: AnyViewHandle, cx: &mut ViewContext<Self>) {
6135                if cx.handle().id() == blurred.id() {
6136                    self.events.lock().push(format!("{} blurred", &self.name));
6137                }
6138            }
6139        }
6140
6141        let view_events: Arc<Mutex<Vec<String>>> = Default::default();
6142        let (_, view_1) = cx.add_window(Default::default(), |_| View {
6143            events: view_events.clone(),
6144            name: "view 1".to_string(),
6145        });
6146        let view_2 = cx.add_view(&view_1, |_| View {
6147            events: view_events.clone(),
6148            name: "view 2".to_string(),
6149        });
6150
6151        let observed_events: Arc<Mutex<Vec<String>>> = Default::default();
6152        view_1.update(cx, |_, cx| {
6153            cx.observe_focus(&view_2, {
6154                let observed_events = observed_events.clone();
6155                move |this, view, focused, cx| {
6156                    let label = if focused { "focus" } else { "blur" };
6157                    observed_events.lock().push(format!(
6158                        "{} observed {}'s {}",
6159                        this.name,
6160                        view.read(cx).name,
6161                        label
6162                    ))
6163                }
6164            })
6165            .detach();
6166        });
6167        view_2.update(cx, |_, cx| {
6168            cx.observe_focus(&view_1, {
6169                let observed_events = observed_events.clone();
6170                move |this, view, focused, cx| {
6171                    let label = if focused { "focus" } else { "blur" };
6172                    observed_events.lock().push(format!(
6173                        "{} observed {}'s {}",
6174                        this.name,
6175                        view.read(cx).name,
6176                        label
6177                    ))
6178                }
6179            })
6180            .detach();
6181        });
6182        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
6183        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
6184
6185        view_1.update(cx, |_, cx| {
6186            // Ensure focus events are sent for all intermediate focuses
6187            cx.focus(&view_2);
6188            cx.focus(&view_1);
6189            cx.focus(&view_2);
6190        });
6191        assert!(cx.is_child_focused(&view_1));
6192        assert!(!cx.is_child_focused(&view_2));
6193        assert_eq!(
6194            mem::take(&mut *view_events.lock()),
6195            [
6196                "view 1 blurred",
6197                "view 2 focused",
6198                "view 2 blurred",
6199                "view 1 focused",
6200                "view 1 blurred",
6201                "view 2 focused"
6202            ],
6203        );
6204        assert_eq!(
6205            mem::take(&mut *observed_events.lock()),
6206            [
6207                "view 2 observed view 1's blur",
6208                "view 1 observed view 2's focus",
6209                "view 1 observed view 2's blur",
6210                "view 2 observed view 1's focus",
6211                "view 2 observed view 1's blur",
6212                "view 1 observed view 2's focus"
6213            ]
6214        );
6215
6216        view_1.update(cx, |_, cx| cx.focus(&view_1));
6217        assert!(!cx.is_child_focused(&view_1));
6218        assert!(!cx.is_child_focused(&view_2));
6219        assert_eq!(
6220            mem::take(&mut *view_events.lock()),
6221            ["view 2 blurred", "view 1 focused"],
6222        );
6223        assert_eq!(
6224            mem::take(&mut *observed_events.lock()),
6225            [
6226                "view 1 observed view 2's blur",
6227                "view 2 observed view 1's focus"
6228            ]
6229        );
6230
6231        view_1.update(cx, |_, cx| cx.focus(&view_2));
6232        assert_eq!(
6233            mem::take(&mut *view_events.lock()),
6234            ["view 1 blurred", "view 2 focused"],
6235        );
6236        assert_eq!(
6237            mem::take(&mut *observed_events.lock()),
6238            [
6239                "view 2 observed view 1's blur",
6240                "view 1 observed view 2's focus"
6241            ]
6242        );
6243
6244        view_1.update(cx, |_, _| drop(view_2));
6245        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
6246        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
6247    }
6248
6249    #[crate::test(self)]
6250    fn test_deserialize_actions(cx: &mut AppContext) {
6251        #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
6252        pub struct ComplexAction {
6253            arg: String,
6254            count: usize,
6255        }
6256
6257        actions!(test::something, [SimpleAction]);
6258        impl_actions!(test::something, [ComplexAction]);
6259
6260        cx.add_global_action(move |_: &SimpleAction, _: &mut AppContext| {});
6261        cx.add_global_action(move |_: &ComplexAction, _: &mut AppContext| {});
6262
6263        let action1 = cx
6264            .deserialize_action(
6265                "test::something::ComplexAction",
6266                Some(r#"{"arg": "a", "count": 5}"#),
6267            )
6268            .unwrap();
6269        let action2 = cx
6270            .deserialize_action("test::something::SimpleAction", None)
6271            .unwrap();
6272        assert_eq!(
6273            action1.as_any().downcast_ref::<ComplexAction>().unwrap(),
6274            &ComplexAction {
6275                arg: "a".to_string(),
6276                count: 5,
6277            }
6278        );
6279        assert_eq!(
6280            action2.as_any().downcast_ref::<SimpleAction>().unwrap(),
6281            &SimpleAction
6282        );
6283    }
6284
6285    #[crate::test(self)]
6286    fn test_dispatch_action(cx: &mut AppContext) {
6287        struct ViewA {
6288            id: usize,
6289        }
6290
6291        impl Entity for ViewA {
6292            type Event = ();
6293        }
6294
6295        impl View for ViewA {
6296            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6297                Empty::new().boxed()
6298            }
6299
6300            fn ui_name() -> &'static str {
6301                "View"
6302            }
6303        }
6304
6305        struct ViewB {
6306            id: usize,
6307        }
6308
6309        impl Entity for ViewB {
6310            type Event = ();
6311        }
6312
6313        impl View for ViewB {
6314            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6315                Empty::new().boxed()
6316            }
6317
6318            fn ui_name() -> &'static str {
6319                "View"
6320            }
6321        }
6322
6323        #[derive(Clone, Default, Deserialize, PartialEq)]
6324        pub struct Action(pub String);
6325
6326        impl_actions!(test, [Action]);
6327
6328        let actions = Rc::new(RefCell::new(Vec::new()));
6329
6330        cx.add_global_action({
6331            let actions = actions.clone();
6332            move |_: &Action, _: &mut AppContext| {
6333                actions.borrow_mut().push("global".to_string());
6334            }
6335        });
6336
6337        cx.add_action({
6338            let actions = actions.clone();
6339            move |view: &mut ViewA, action: &Action, cx| {
6340                assert_eq!(action.0, "bar");
6341                cx.propagate_action();
6342                actions.borrow_mut().push(format!("{} a", view.id));
6343            }
6344        });
6345
6346        cx.add_action({
6347            let actions = actions.clone();
6348            move |view: &mut ViewA, _: &Action, cx| {
6349                if view.id != 1 {
6350                    cx.add_view(|cx| {
6351                        cx.propagate_action(); // Still works on a nested ViewContext
6352                        ViewB { id: 5 }
6353                    });
6354                }
6355                actions.borrow_mut().push(format!("{} b", view.id));
6356            }
6357        });
6358
6359        cx.add_action({
6360            let actions = actions.clone();
6361            move |view: &mut ViewB, _: &Action, cx| {
6362                cx.propagate_action();
6363                actions.borrow_mut().push(format!("{} c", view.id));
6364            }
6365        });
6366
6367        cx.add_action({
6368            let actions = actions.clone();
6369            move |view: &mut ViewB, _: &Action, cx| {
6370                cx.propagate_action();
6371                actions.borrow_mut().push(format!("{} d", view.id));
6372            }
6373        });
6374
6375        cx.capture_action({
6376            let actions = actions.clone();
6377            move |view: &mut ViewA, _: &Action, cx| {
6378                cx.propagate_action();
6379                actions.borrow_mut().push(format!("{} capture", view.id));
6380            }
6381        });
6382
6383        let observed_actions = Rc::new(RefCell::new(Vec::new()));
6384        cx.observe_actions({
6385            let observed_actions = observed_actions.clone();
6386            move |action_id, _| observed_actions.borrow_mut().push(action_id)
6387        })
6388        .detach();
6389
6390        let (window_id, view_1) = cx.add_window(Default::default(), |_| ViewA { id: 1 });
6391        let view_2 = cx.add_view(&view_1, |_| ViewB { id: 2 });
6392        let view_3 = cx.add_view(&view_2, |_| ViewA { id: 3 });
6393        let view_4 = cx.add_view(&view_3, |_| ViewB { id: 4 });
6394
6395        cx.handle_dispatch_action_from_effect(
6396            window_id,
6397            Some(view_4.id()),
6398            &Action("bar".to_string()),
6399        );
6400
6401        assert_eq!(
6402            *actions.borrow(),
6403            vec![
6404                "1 capture",
6405                "3 capture",
6406                "4 d",
6407                "4 c",
6408                "3 b",
6409                "3 a",
6410                "2 d",
6411                "2 c",
6412                "1 b"
6413            ]
6414        );
6415        assert_eq!(*observed_actions.borrow(), [Action::default().id()]);
6416
6417        // Remove view_1, which doesn't propagate the action
6418
6419        let (window_id, view_2) = cx.add_window(Default::default(), |_| ViewB { id: 2 });
6420        let view_3 = cx.add_view(&view_2, |_| ViewA { id: 3 });
6421        let view_4 = cx.add_view(&view_3, |_| ViewB { id: 4 });
6422
6423        actions.borrow_mut().clear();
6424        cx.handle_dispatch_action_from_effect(
6425            window_id,
6426            Some(view_4.id()),
6427            &Action("bar".to_string()),
6428        );
6429
6430        assert_eq!(
6431            *actions.borrow(),
6432            vec![
6433                "3 capture",
6434                "4 d",
6435                "4 c",
6436                "3 b",
6437                "3 a",
6438                "2 d",
6439                "2 c",
6440                "global"
6441            ]
6442        );
6443        assert_eq!(
6444            *observed_actions.borrow(),
6445            [Action::default().id(), Action::default().id()]
6446        );
6447    }
6448
6449    #[crate::test(self)]
6450    fn test_dispatch_keystroke(cx: &mut AppContext) {
6451        #[derive(Clone, Deserialize, PartialEq)]
6452        pub struct Action(String);
6453
6454        impl_actions!(test, [Action]);
6455
6456        struct View {
6457            id: usize,
6458            keymap_context: KeymapContext,
6459        }
6460
6461        impl Entity for View {
6462            type Event = ();
6463        }
6464
6465        impl super::View for View {
6466            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6467                Empty::new().boxed()
6468            }
6469
6470            fn ui_name() -> &'static str {
6471                "View"
6472            }
6473
6474            fn keymap_context(&self, _: &AppContext) -> KeymapContext {
6475                self.keymap_context.clone()
6476            }
6477        }
6478
6479        impl View {
6480            fn new(id: usize) -> Self {
6481                View {
6482                    id,
6483                    keymap_context: KeymapContext::default(),
6484                }
6485            }
6486        }
6487
6488        let mut view_1 = View::new(1);
6489        let mut view_2 = View::new(2);
6490        let mut view_3 = View::new(3);
6491        view_1.keymap_context.add_identifier("a");
6492        view_2.keymap_context.add_identifier("a");
6493        view_2.keymap_context.add_identifier("b");
6494        view_3.keymap_context.add_identifier("a");
6495        view_3.keymap_context.add_identifier("b");
6496        view_3.keymap_context.add_identifier("c");
6497
6498        let (window_id, view_1) = cx.add_window(Default::default(), |_| view_1);
6499        let view_2 = cx.add_view(&view_1, |_| view_2);
6500        let _view_3 = cx.add_view(&view_2, |cx| {
6501            cx.focus_self();
6502            view_3
6503        });
6504
6505        // This binding only dispatches an action on view 2 because that view will have
6506        // "a" and "b" in its context, but not "c".
6507        cx.add_bindings(vec![Binding::new(
6508            "a",
6509            Action("a".to_string()),
6510            Some("a && b && !c"),
6511        )]);
6512
6513        cx.add_bindings(vec![Binding::new("b", Action("b".to_string()), None)]);
6514
6515        // This binding only dispatches an action on views 2 and 3, because they have
6516        // a parent view with a in its context
6517        cx.add_bindings(vec![Binding::new(
6518            "c",
6519            Action("c".to_string()),
6520            Some("b > c"),
6521        )]);
6522
6523        // This binding only dispatches an action on view 2, because they have
6524        // a parent view with a in its context
6525        cx.add_bindings(vec![Binding::new(
6526            "d",
6527            Action("d".to_string()),
6528            Some("a && !b > b"),
6529        )]);
6530
6531        let actions = Rc::new(RefCell::new(Vec::new()));
6532        cx.add_action({
6533            let actions = actions.clone();
6534            move |view: &mut View, action: &Action, cx| {
6535                actions
6536                    .borrow_mut()
6537                    .push(format!("{} {}", view.id, action.0));
6538
6539                if action.0 == "b" {
6540                    cx.propagate_action();
6541                }
6542            }
6543        });
6544
6545        cx.add_global_action({
6546            let actions = actions.clone();
6547            move |action: &Action, _| {
6548                actions.borrow_mut().push(format!("global {}", action.0));
6549            }
6550        });
6551
6552        cx.dispatch_keystroke(window_id, &Keystroke::parse("a").unwrap());
6553        assert_eq!(&*actions.borrow(), &["2 a"]);
6554        actions.borrow_mut().clear();
6555
6556        cx.dispatch_keystroke(window_id, &Keystroke::parse("b").unwrap());
6557        assert_eq!(&*actions.borrow(), &["3 b", "2 b", "1 b", "global b"]);
6558        actions.borrow_mut().clear();
6559
6560        cx.dispatch_keystroke(window_id, &Keystroke::parse("c").unwrap());
6561        assert_eq!(&*actions.borrow(), &["3 c"]);
6562        actions.borrow_mut().clear();
6563
6564        cx.dispatch_keystroke(window_id, &Keystroke::parse("d").unwrap());
6565        assert_eq!(&*actions.borrow(), &["2 d"]);
6566        actions.borrow_mut().clear();
6567    }
6568
6569    #[crate::test(self)]
6570    fn test_keystrokes_for_action(cx: &mut AppContext) {
6571        actions!(test, [Action1, Action2, GlobalAction]);
6572
6573        struct View1 {}
6574        struct View2 {}
6575
6576        impl Entity for View1 {
6577            type Event = ();
6578        }
6579        impl Entity for View2 {
6580            type Event = ();
6581        }
6582
6583        impl super::View for View1 {
6584            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6585                Empty::new().boxed()
6586            }
6587            fn ui_name() -> &'static str {
6588                "View1"
6589            }
6590        }
6591        impl super::View for View2 {
6592            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6593                Empty::new().boxed()
6594            }
6595            fn ui_name() -> &'static str {
6596                "View2"
6597            }
6598        }
6599
6600        let (window_id, view_1) = cx.add_window(Default::default(), |_| View1 {});
6601        let view_2 = cx.add_view(&view_1, |cx| {
6602            cx.focus_self();
6603            View2 {}
6604        });
6605
6606        cx.add_action(|_: &mut View1, _: &Action1, _cx| {});
6607        cx.add_action(|_: &mut View2, _: &Action2, _cx| {});
6608        cx.add_global_action(|_: &GlobalAction, _| {});
6609
6610        cx.add_bindings(vec![
6611            Binding::new("a", Action1, Some("View1")),
6612            Binding::new("b", Action2, Some("View1 > View2")),
6613            Binding::new("c", GlobalAction, Some("View3")), // View 3 does not exist
6614        ]);
6615
6616        // Sanity check
6617        assert_eq!(
6618            cx.keystrokes_for_action(window_id, view_1.id(), &Action1)
6619                .unwrap()
6620                .as_slice(),
6621            &[Keystroke::parse("a").unwrap()]
6622        );
6623        assert_eq!(
6624            cx.keystrokes_for_action(window_id, view_2.id(), &Action2)
6625                .unwrap()
6626                .as_slice(),
6627            &[Keystroke::parse("b").unwrap()]
6628        );
6629
6630        // The 'a' keystroke propagates up the view tree from view_2
6631        // to view_1. The action, Action1, is handled by view_1.
6632        assert_eq!(
6633            cx.keystrokes_for_action(window_id, view_2.id(), &Action1)
6634                .unwrap()
6635                .as_slice(),
6636            &[Keystroke::parse("a").unwrap()]
6637        );
6638
6639        // Actions that are handled below the current view don't have bindings
6640        assert_eq!(
6641            cx.keystrokes_for_action(window_id, view_1.id(), &Action2),
6642            None
6643        );
6644
6645        // Actions that are handled in other branches of the tree should not have a binding
6646        assert_eq!(
6647            cx.keystrokes_for_action(window_id, view_2.id(), &GlobalAction),
6648            None
6649        );
6650
6651        // Produces a list of actions and key bindings
6652        fn available_actions(
6653            window_id: usize,
6654            view_id: usize,
6655            cx: &mut AppContext,
6656        ) -> Vec<(&'static str, Vec<Keystroke>)> {
6657            cx.available_actions(window_id, view_id)
6658                .map(|(action_name, _, bindings)| {
6659                    (
6660                        action_name,
6661                        bindings
6662                            .iter()
6663                            .map(|binding| binding.keystrokes()[0].clone())
6664                            .collect::<Vec<_>>(),
6665                    )
6666                })
6667                .sorted_by(|(name1, _), (name2, _)| name1.cmp(name2))
6668                .collect()
6669        }
6670
6671        // Check that global actions do not have a binding, even if a binding does exist in another view
6672        assert_eq!(
6673            &available_actions(window_id, view_1.id(), cx),
6674            &[
6675                ("test::Action1", vec![Keystroke::parse("a").unwrap()]),
6676                ("test::GlobalAction", vec![])
6677            ],
6678        );
6679
6680        // Check that view 1 actions and bindings are available even when called from view 2
6681        assert_eq!(
6682            &available_actions(window_id, view_2.id(), cx),
6683            &[
6684                ("test::Action1", vec![Keystroke::parse("a").unwrap()]),
6685                ("test::Action2", vec![Keystroke::parse("b").unwrap()]),
6686                ("test::GlobalAction", vec![]),
6687            ],
6688        );
6689    }
6690
6691    #[crate::test(self)]
6692    async fn test_model_condition(cx: &mut TestAppContext) {
6693        struct Counter(usize);
6694
6695        impl super::Entity for Counter {
6696            type Event = ();
6697        }
6698
6699        impl Counter {
6700            fn inc(&mut self, cx: &mut ModelContext<Self>) {
6701                self.0 += 1;
6702                cx.notify();
6703            }
6704        }
6705
6706        let model = cx.add_model(|_| Counter(0));
6707
6708        let condition1 = model.condition(cx, |model, _| model.0 == 2);
6709        let condition2 = model.condition(cx, |model, _| model.0 == 3);
6710        smol::pin!(condition1, condition2);
6711
6712        model.update(cx, |model, cx| model.inc(cx));
6713        assert_eq!(poll_once(&mut condition1).await, None);
6714        assert_eq!(poll_once(&mut condition2).await, None);
6715
6716        model.update(cx, |model, cx| model.inc(cx));
6717        assert_eq!(poll_once(&mut condition1).await, Some(()));
6718        assert_eq!(poll_once(&mut condition2).await, None);
6719
6720        model.update(cx, |model, cx| model.inc(cx));
6721        assert_eq!(poll_once(&mut condition2).await, Some(()));
6722
6723        model.update(cx, |_, cx| cx.notify());
6724    }
6725
6726    #[crate::test(self)]
6727    #[should_panic]
6728    async fn test_model_condition_timeout(cx: &mut TestAppContext) {
6729        struct Model;
6730
6731        impl super::Entity for Model {
6732            type Event = ();
6733        }
6734
6735        let model = cx.add_model(|_| Model);
6736        model.condition(cx, |_, _| false).await;
6737    }
6738
6739    #[crate::test(self)]
6740    #[should_panic(expected = "model dropped with pending condition")]
6741    async fn test_model_condition_panic_on_drop(cx: &mut TestAppContext) {
6742        struct Model;
6743
6744        impl super::Entity for Model {
6745            type Event = ();
6746        }
6747
6748        let model = cx.add_model(|_| Model);
6749        let condition = model.condition(cx, |_, _| false);
6750        cx.update(|_| drop(model));
6751        condition.await;
6752    }
6753
6754    #[crate::test(self)]
6755    async fn test_view_condition(cx: &mut TestAppContext) {
6756        struct Counter(usize);
6757
6758        impl super::Entity for Counter {
6759            type Event = ();
6760        }
6761
6762        impl super::View for Counter {
6763            fn ui_name() -> &'static str {
6764                "test view"
6765            }
6766
6767            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6768                Empty::new().boxed()
6769            }
6770        }
6771
6772        impl Counter {
6773            fn inc(&mut self, cx: &mut ViewContext<Self>) {
6774                self.0 += 1;
6775                cx.notify();
6776            }
6777        }
6778
6779        let (_, view) = cx.add_window(|_| Counter(0));
6780
6781        let condition1 = view.condition(cx, |view, _| view.0 == 2);
6782        let condition2 = view.condition(cx, |view, _| view.0 == 3);
6783        smol::pin!(condition1, condition2);
6784
6785        view.update(cx, |view, cx| view.inc(cx));
6786        assert_eq!(poll_once(&mut condition1).await, None);
6787        assert_eq!(poll_once(&mut condition2).await, None);
6788
6789        view.update(cx, |view, cx| view.inc(cx));
6790        assert_eq!(poll_once(&mut condition1).await, Some(()));
6791        assert_eq!(poll_once(&mut condition2).await, None);
6792
6793        view.update(cx, |view, cx| view.inc(cx));
6794        assert_eq!(poll_once(&mut condition2).await, Some(()));
6795        view.update(cx, |_, cx| cx.notify());
6796    }
6797
6798    #[crate::test(self)]
6799    #[should_panic]
6800    async fn test_view_condition_timeout(cx: &mut TestAppContext) {
6801        let (_, view) = cx.add_window(|_| TestView::default());
6802        view.condition(cx, |_, _| false).await;
6803    }
6804
6805    #[crate::test(self)]
6806    #[should_panic(expected = "view dropped with pending condition")]
6807    async fn test_view_condition_panic_on_drop(cx: &mut TestAppContext) {
6808        let (_, root_view) = cx.add_window(|_| TestView::default());
6809        let view = cx.add_view(&root_view, |_| TestView::default());
6810
6811        let condition = view.condition(cx, |_, _| false);
6812        cx.update(|_| drop(view));
6813        condition.await;
6814    }
6815
6816    #[crate::test(self)]
6817    fn test_refresh_windows(cx: &mut AppContext) {
6818        struct View(usize);
6819
6820        impl super::Entity for View {
6821            type Event = ();
6822        }
6823
6824        impl super::View for View {
6825            fn ui_name() -> &'static str {
6826                "test view"
6827            }
6828
6829            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6830                Empty::new().named(format!("render count: {}", post_inc(&mut self.0)))
6831            }
6832        }
6833
6834        let (window_id, root_view) = cx.add_window(Default::default(), |_| View(0));
6835        let presenter = cx.presenters_and_platform_windows[&window_id].0.clone();
6836
6837        assert_eq!(
6838            presenter.borrow().rendered_views[&root_view.id()].name(),
6839            Some("render count: 0")
6840        );
6841
6842        let view = cx.add_view(&root_view, |cx| {
6843            cx.refresh_windows();
6844            View(0)
6845        });
6846
6847        assert_eq!(
6848            presenter.borrow().rendered_views[&root_view.id()].name(),
6849            Some("render count: 1")
6850        );
6851        assert_eq!(
6852            presenter.borrow().rendered_views[&view.id()].name(),
6853            Some("render count: 0")
6854        );
6855
6856        cx.update(|cx| cx.refresh_windows());
6857        assert_eq!(
6858            presenter.borrow().rendered_views[&root_view.id()].name(),
6859            Some("render count: 2")
6860        );
6861        assert_eq!(
6862            presenter.borrow().rendered_views[&view.id()].name(),
6863            Some("render count: 1")
6864        );
6865
6866        cx.update(|cx| {
6867            cx.refresh_windows();
6868            drop(view);
6869        });
6870        assert_eq!(
6871            presenter.borrow().rendered_views[&root_view.id()].name(),
6872            Some("render count: 3")
6873        );
6874        assert_eq!(presenter.borrow().rendered_views.len(), 1);
6875    }
6876
6877    #[crate::test(self)]
6878    async fn test_labeled_tasks(cx: &mut TestAppContext) {
6879        assert_eq!(None, cx.update(|cx| cx.active_labeled_tasks().next()));
6880        let (mut sender, mut reciever) = postage::oneshot::channel::<()>();
6881        let task = cx
6882            .update(|cx| cx.spawn_labeled("Test Label", |_| async move { reciever.recv().await }));
6883
6884        assert_eq!(
6885            Some("Test Label"),
6886            cx.update(|cx| cx.active_labeled_tasks().next())
6887        );
6888        sender
6889            .send(())
6890            .await
6891            .expect("Could not send message to complete task");
6892        task.await;
6893
6894        assert_eq!(None, cx.update(|cx| cx.active_labeled_tasks().next()));
6895    }
6896
6897    #[crate::test(self)]
6898    async fn test_window_activation(cx: &mut TestAppContext) {
6899        struct View(&'static str);
6900
6901        impl super::Entity for View {
6902            type Event = ();
6903        }
6904
6905        impl super::View for View {
6906            fn ui_name() -> &'static str {
6907                "test view"
6908            }
6909
6910            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6911                Empty::new().boxed()
6912            }
6913        }
6914
6915        let events = Rc::new(RefCell::new(Vec::new()));
6916        let (window_1, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6917            cx.observe_window_activation({
6918                let events = events.clone();
6919                move |this, active, _| events.borrow_mut().push((this.0, active))
6920            })
6921            .detach();
6922            View("window 1")
6923        });
6924        assert_eq!(mem::take(&mut *events.borrow_mut()), [("window 1", true)]);
6925
6926        let (window_2, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6927            cx.observe_window_activation({
6928                let events = events.clone();
6929                move |this, active, _| events.borrow_mut().push((this.0, active))
6930            })
6931            .detach();
6932            View("window 2")
6933        });
6934        assert_eq!(
6935            mem::take(&mut *events.borrow_mut()),
6936            [("window 1", false), ("window 2", true)]
6937        );
6938
6939        let (window_3, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6940            cx.observe_window_activation({
6941                let events = events.clone();
6942                move |this, active, _| events.borrow_mut().push((this.0, active))
6943            })
6944            .detach();
6945            View("window 3")
6946        });
6947        assert_eq!(
6948            mem::take(&mut *events.borrow_mut()),
6949            [("window 2", false), ("window 3", true)]
6950        );
6951
6952        cx.simulate_window_activation(Some(window_2));
6953        assert_eq!(
6954            mem::take(&mut *events.borrow_mut()),
6955            [("window 3", false), ("window 2", true)]
6956        );
6957
6958        cx.simulate_window_activation(Some(window_1));
6959        assert_eq!(
6960            mem::take(&mut *events.borrow_mut()),
6961            [("window 2", false), ("window 1", true)]
6962        );
6963
6964        cx.simulate_window_activation(Some(window_3));
6965        assert_eq!(
6966            mem::take(&mut *events.borrow_mut()),
6967            [("window 1", false), ("window 3", true)]
6968        );
6969
6970        cx.simulate_window_activation(Some(window_3));
6971        assert_eq!(mem::take(&mut *events.borrow_mut()), []);
6972    }
6973
6974    #[crate::test(self)]
6975    fn test_child_view(cx: &mut AppContext) {
6976        struct Child {
6977            rendered: Rc<Cell<bool>>,
6978            dropped: Rc<Cell<bool>>,
6979        }
6980
6981        impl super::Entity for Child {
6982            type Event = ();
6983        }
6984
6985        impl super::View for Child {
6986            fn ui_name() -> &'static str {
6987                "child view"
6988            }
6989
6990            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6991                self.rendered.set(true);
6992                Empty::new().boxed()
6993            }
6994        }
6995
6996        impl Drop for Child {
6997            fn drop(&mut self) {
6998                self.dropped.set(true);
6999            }
7000        }
7001
7002        struct Parent {
7003            child: Option<ViewHandle<Child>>,
7004        }
7005
7006        impl super::Entity for Parent {
7007            type Event = ();
7008        }
7009
7010        impl super::View for Parent {
7011            fn ui_name() -> &'static str {
7012                "parent view"
7013            }
7014
7015            fn render(&mut self, cx: &mut RenderContext<Self>) -> ElementBox {
7016                if let Some(child) = self.child.as_ref() {
7017                    ChildView::new(child, cx).boxed()
7018                } else {
7019                    Empty::new().boxed()
7020                }
7021            }
7022        }
7023
7024        let child_rendered = Rc::new(Cell::new(false));
7025        let child_dropped = Rc::new(Cell::new(false));
7026        let (_, root_view) = cx.add_window(Default::default(), |cx| Parent {
7027            child: Some(cx.add_view(|_| Child {
7028                rendered: child_rendered.clone(),
7029                dropped: child_dropped.clone(),
7030            })),
7031        });
7032        assert!(child_rendered.take());
7033        assert!(!child_dropped.take());
7034
7035        root_view.update(cx, |view, cx| {
7036            view.child.take();
7037            cx.notify();
7038        });
7039        assert!(!child_rendered.take());
7040        assert!(child_dropped.take());
7041    }
7042
7043    #[derive(Default)]
7044    struct TestView {
7045        events: Vec<String>,
7046    }
7047
7048    impl Entity for TestView {
7049        type Event = String;
7050    }
7051
7052    impl View for TestView {
7053        fn ui_name() -> &'static str {
7054            "TestView"
7055        }
7056
7057        fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7058            Empty::new().boxed()
7059        }
7060    }
7061}