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;
   7pub(crate) mod window;
   8mod window_input_handler;
   9
  10use std::{
  11    any::{type_name, Any, TypeId},
  12    cell::RefCell,
  13    fmt::{self, Debug},
  14    hash::{Hash, Hasher},
  15    marker::PhantomData,
  16    mem,
  17    ops::{Deref, DerefMut, Range},
  18    path::{Path, PathBuf},
  19    pin::Pin,
  20    rc::{self, Rc},
  21    sync::{Arc, Weak},
  22    time::Duration,
  23};
  24
  25use anyhow::{anyhow, Context, Result};
  26use parking_lot::Mutex;
  27use postage::oneshot;
  28use smol::prelude::*;
  29use util::ResultExt;
  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::{AnyElement, AnyRootElement, RootElement},
  45    executor::{self, Task},
  46    json,
  47    keymap_matcher::{self, Binding, KeymapContext, KeymapMatcher, Keystroke, MatchResult},
  48    platform::{
  49        self, FontSystem, KeyDownEvent, KeyUpEvent, ModifiersChangedEvent, MouseButton,
  50        PathPromptOptions, Platform, PromptLevel, WindowBounds, WindowOptions,
  51    },
  52    util::post_inc,
  53    window::{Window, WindowContext},
  54    AssetCache, AssetSource, ClipboardItem, FontCache, MouseRegionId,
  55};
  56
  57use self::ref_counts::RefCounts;
  58
  59pub trait Entity: 'static {
  60    type Event;
  61
  62    fn release(&mut self, _: &mut AppContext) {}
  63    fn app_will_quit(
  64        &mut self,
  65        _: &mut AppContext,
  66    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
  67        None
  68    }
  69}
  70
  71pub trait View: Entity + Sized {
  72    fn ui_name() -> &'static str;
  73    fn render(&mut self, cx: &mut ViewContext<'_, '_, Self>) -> AnyElement<Self>;
  74    fn focus_in(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  75    fn focus_out(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  76    fn key_down(&mut self, _: &KeyDownEvent, _: &mut ViewContext<Self>) -> bool {
  77        false
  78    }
  79    fn key_up(&mut self, _: &KeyUpEvent, _: &mut ViewContext<Self>) -> bool {
  80        false
  81    }
  82    fn modifiers_changed(&mut self, _: &ModifiersChangedEvent, _: &mut ViewContext<Self>) -> bool {
  83        false
  84    }
  85
  86    fn keymap_context(&self, _: &AppContext) -> keymap_matcher::KeymapContext {
  87        Self::default_keymap_context()
  88    }
  89    fn default_keymap_context() -> keymap_matcher::KeymapContext {
  90        let mut cx = keymap_matcher::KeymapContext::default();
  91        cx.add_identifier(Self::ui_name());
  92        cx
  93    }
  94    fn debug_json(&self, _: &AppContext) -> serde_json::Value {
  95        serde_json::Value::Null
  96    }
  97
  98    fn text_for_range(&self, _: Range<usize>, _: &AppContext) -> Option<String> {
  99        None
 100    }
 101    fn selected_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
 102        None
 103    }
 104    fn marked_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
 105        None
 106    }
 107    fn unmark_text(&mut self, _: &mut ViewContext<Self>) {}
 108    fn replace_text_in_range(
 109        &mut self,
 110        _: Option<Range<usize>>,
 111        _: &str,
 112        _: &mut ViewContext<Self>,
 113    ) {
 114    }
 115    fn replace_and_mark_text_in_range(
 116        &mut self,
 117        _: Option<Range<usize>>,
 118        _: &str,
 119        _: Option<Range<usize>>,
 120        _: &mut ViewContext<Self>,
 121    ) {
 122    }
 123}
 124
 125pub trait BorrowAppContext {
 126    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T;
 127    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T;
 128}
 129
 130pub trait BorrowWindowContext {
 131    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T;
 132    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T;
 133}
 134
 135#[derive(Clone)]
 136pub struct App(Rc<RefCell<AppContext>>);
 137
 138impl App {
 139    pub fn new(asset_source: impl AssetSource) -> Result<Self> {
 140        let platform = platform::current::platform();
 141        let foreground = Rc::new(executor::Foreground::platform(platform.dispatcher())?);
 142        let foreground_platform = platform::current::foreground_platform(foreground.clone());
 143        let app = Self(Rc::new(RefCell::new(AppContext::new(
 144            foreground,
 145            Arc::new(executor::Background::new()),
 146            platform.clone(),
 147            foreground_platform.clone(),
 148            Arc::new(FontCache::new(platform.fonts())),
 149            Default::default(),
 150            asset_source,
 151        ))));
 152
 153        foreground_platform.on_quit(Box::new({
 154            let cx = app.0.clone();
 155            move || {
 156                cx.borrow_mut().quit();
 157            }
 158        }));
 159        setup_menu_handlers(foreground_platform.as_ref(), &app);
 160
 161        app.0.borrow_mut().weak_self = Some(Rc::downgrade(&app.0));
 162        Ok(app)
 163    }
 164
 165    pub fn background(&self) -> Arc<executor::Background> {
 166        self.0.borrow().background().clone()
 167    }
 168
 169    pub fn on_become_active<F>(self, mut callback: F) -> Self
 170    where
 171        F: 'static + FnMut(&mut AppContext),
 172    {
 173        let cx = self.0.clone();
 174        self.0
 175            .borrow_mut()
 176            .foreground_platform
 177            .on_become_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 178        self
 179    }
 180
 181    pub fn on_resign_active<F>(self, mut callback: F) -> Self
 182    where
 183        F: 'static + FnMut(&mut AppContext),
 184    {
 185        let cx = self.0.clone();
 186        self.0
 187            .borrow_mut()
 188            .foreground_platform
 189            .on_resign_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 190        self
 191    }
 192
 193    pub fn on_quit<F>(&mut self, mut callback: F) -> &mut Self
 194    where
 195        F: 'static + FnMut(&mut AppContext),
 196    {
 197        let cx = self.0.clone();
 198        self.0
 199            .borrow_mut()
 200            .foreground_platform
 201            .on_quit(Box::new(move || callback(&mut *cx.borrow_mut())));
 202        self
 203    }
 204
 205    /// Handle the application being re-activated when no windows are open.
 206    pub fn on_reopen<F>(&mut self, mut callback: F) -> &mut Self
 207    where
 208        F: 'static + FnMut(&mut AppContext),
 209    {
 210        let cx = self.0.clone();
 211        self.0
 212            .borrow_mut()
 213            .foreground_platform
 214            .on_reopen(Box::new(move || callback(&mut *cx.borrow_mut())));
 215        self
 216    }
 217
 218    pub fn on_event<F>(&mut self, mut callback: F) -> &mut Self
 219    where
 220        F: 'static + FnMut(Event, &mut AppContext) -> bool,
 221    {
 222        let cx = self.0.clone();
 223        self.0
 224            .borrow_mut()
 225            .foreground_platform
 226            .on_event(Box::new(move |event| {
 227                callback(event, &mut *cx.borrow_mut())
 228            }));
 229        self
 230    }
 231
 232    pub fn on_open_urls<F>(&mut self, mut callback: F) -> &mut Self
 233    where
 234        F: 'static + FnMut(Vec<String>, &mut AppContext),
 235    {
 236        let cx = self.0.clone();
 237        self.0
 238            .borrow_mut()
 239            .foreground_platform
 240            .on_open_urls(Box::new(move |urls| callback(urls, &mut *cx.borrow_mut())));
 241        self
 242    }
 243
 244    pub fn run<F>(self, on_finish_launching: F)
 245    where
 246        F: 'static + FnOnce(&mut AppContext),
 247    {
 248        let platform = self.0.borrow().foreground_platform.clone();
 249        platform.run(Box::new(move || {
 250            let mut cx = self.0.borrow_mut();
 251            let cx = &mut *cx;
 252            crate::views::init(cx);
 253            on_finish_launching(cx);
 254        }))
 255    }
 256
 257    pub fn platform(&self) -> Arc<dyn Platform> {
 258        self.0.borrow().platform.clone()
 259    }
 260
 261    pub fn font_cache(&self) -> Arc<FontCache> {
 262        self.0.borrow().font_cache.clone()
 263    }
 264
 265    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, callback: F) -> T {
 266        let mut state = self.0.borrow_mut();
 267        let result = state.update(callback);
 268        state.pending_notifications.clear();
 269        result
 270    }
 271
 272    fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 273        &mut self,
 274        window_id: usize,
 275        callback: F,
 276    ) -> Option<T> {
 277        let mut state = self.0.borrow_mut();
 278        let result = state.update_window(window_id, callback);
 279        state.pending_notifications.clear();
 280        result
 281    }
 282}
 283
 284#[derive(Clone)]
 285pub struct AsyncAppContext(Rc<RefCell<AppContext>>);
 286
 287impl AsyncAppContext {
 288    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
 289    where
 290        F: FnOnce(AsyncAppContext) -> Fut,
 291        Fut: 'static + Future<Output = T>,
 292        T: 'static,
 293    {
 294        self.0.borrow().foreground.spawn(f(self.clone()))
 295    }
 296
 297    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 298        callback(&*self.0.borrow())
 299    }
 300
 301    pub fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, callback: F) -> T {
 302        self.0.borrow_mut().update(callback)
 303    }
 304
 305    pub fn read_window<T, F: FnOnce(&WindowContext) -> T>(
 306        &self,
 307        window_id: usize,
 308        callback: F,
 309    ) -> Option<T> {
 310        self.0.borrow_mut().read_window(window_id, callback)
 311    }
 312
 313    pub fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 314        &mut self,
 315        window_id: usize,
 316        callback: F,
 317    ) -> Option<T> {
 318        self.0.borrow_mut().update_window(window_id, callback)
 319    }
 320
 321    pub fn debug_elements(&self, window_id: usize) -> Option<json::Value> {
 322        self.0.borrow().read_window(window_id, |cx| {
 323            let root_view = cx.window.root_view();
 324            let root_element = cx.window.rendered_views.get(&root_view.id())?;
 325            root_element.debug(cx).log_err()
 326        })?
 327    }
 328
 329    pub fn dispatch_action(
 330        &mut self,
 331        window_id: usize,
 332        view_id: usize,
 333        action: &dyn Action,
 334    ) -> Result<()> {
 335        self.0
 336            .borrow_mut()
 337            .update_window(window_id, |window| {
 338                window.dispatch_action(Some(view_id), action);
 339            })
 340            .ok_or_else(|| anyhow!("window not found"))
 341    }
 342
 343    pub fn has_window(&self, window_id: usize) -> bool {
 344        self.read(|cx| cx.windows.contains_key(&window_id))
 345    }
 346
 347    pub fn window_is_active(&self, window_id: usize) -> bool {
 348        self.read(|cx| cx.windows.get(&window_id).map_or(false, |w| w.is_active))
 349    }
 350
 351    pub fn root_view(&self, window_id: usize) -> Option<AnyViewHandle> {
 352        self.read(|cx| cx.windows.get(&window_id).map(|w| w.root_view().clone()))
 353    }
 354
 355    pub fn window_ids(&self) -> Vec<usize> {
 356        self.read(|cx| cx.windows.keys().copied().collect())
 357    }
 358
 359    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 360    where
 361        T: Entity,
 362        F: FnOnce(&mut ModelContext<T>) -> T,
 363    {
 364        self.update(|cx| cx.add_model(build_model))
 365    }
 366
 367    pub fn add_window<T, F>(
 368        &mut self,
 369        window_options: WindowOptions,
 370        build_root_view: F,
 371    ) -> (usize, ViewHandle<T>)
 372    where
 373        T: View,
 374        F: FnOnce(&mut ViewContext<T>) -> T,
 375    {
 376        self.update(|cx| cx.add_window(window_options, build_root_view))
 377    }
 378
 379    pub fn remove_window(&mut self, window_id: usize) {
 380        self.update_window(window_id, |cx| cx.remove_window());
 381    }
 382
 383    pub fn activate_window(&mut self, window_id: usize) {
 384        self.update_window(window_id, |cx| cx.activate_window());
 385    }
 386
 387    // TODO: Can we eliminate this method and move it to WindowContext then call it with update_window?s
 388    pub fn prompt(
 389        &mut self,
 390        window_id: usize,
 391        level: PromptLevel,
 392        msg: &str,
 393        answers: &[&str],
 394    ) -> Option<oneshot::Receiver<usize>> {
 395        self.update_window(window_id, |cx| cx.prompt(level, msg, answers))
 396    }
 397
 398    pub fn platform(&self) -> Arc<dyn Platform> {
 399        self.0.borrow().platform().clone()
 400    }
 401
 402    pub fn foreground(&self) -> Rc<executor::Foreground> {
 403        self.0.borrow().foreground.clone()
 404    }
 405
 406    pub fn background(&self) -> Arc<executor::Background> {
 407        self.0.borrow().background.clone()
 408    }
 409}
 410
 411impl BorrowAppContext for AsyncAppContext {
 412    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
 413        self.0.borrow().read_with(f)
 414    }
 415
 416    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
 417        self.0.borrow_mut().update(f)
 418    }
 419}
 420
 421type ActionCallback = dyn FnMut(&mut dyn AnyView, &dyn Action, &mut WindowContext, usize);
 422type GlobalActionCallback = dyn FnMut(&dyn Action, &mut AppContext);
 423
 424type SubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool>;
 425type GlobalSubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut AppContext)>;
 426type ObservationCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 427type GlobalObservationCallback = Box<dyn FnMut(&mut AppContext)>;
 428type FocusObservationCallback = Box<dyn FnMut(bool, &mut WindowContext) -> bool>;
 429type ReleaseObservationCallback = Box<dyn FnMut(&dyn Any, &mut AppContext)>;
 430type ActionObservationCallback = Box<dyn FnMut(TypeId, &mut AppContext)>;
 431type WindowActivationCallback = Box<dyn FnMut(bool, &mut WindowContext) -> bool>;
 432type WindowFullscreenCallback = Box<dyn FnMut(bool, &mut WindowContext) -> bool>;
 433type WindowBoundsCallback = Box<dyn FnMut(WindowBounds, Uuid, &mut WindowContext) -> bool>;
 434type KeystrokeCallback =
 435    Box<dyn FnMut(&Keystroke, &MatchResult, Option<&Box<dyn Action>>, &mut WindowContext) -> bool>;
 436type ActiveLabeledTasksCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 437type DeserializeActionCallback = fn(json: &str) -> anyhow::Result<Box<dyn Action>>;
 438type WindowShouldCloseSubscriptionCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 439
 440pub struct AppContext {
 441    models: HashMap<usize, Box<dyn AnyModel>>,
 442    views: HashMap<(usize, usize), Box<dyn AnyView>>,
 443    windows: HashMap<usize, Window>,
 444    globals: HashMap<TypeId, Box<dyn Any>>,
 445    element_states: HashMap<ElementStateId, Box<dyn Any>>,
 446    background: Arc<executor::Background>,
 447    ref_counts: Arc<Mutex<RefCounts>>,
 448
 449    weak_self: Option<rc::Weak<RefCell<Self>>>,
 450    platform: Arc<dyn Platform>,
 451    foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 452    pub asset_cache: Arc<AssetCache>,
 453    font_system: Arc<dyn FontSystem>,
 454    pub font_cache: Arc<FontCache>,
 455    action_deserializers: HashMap<&'static str, (TypeId, DeserializeActionCallback)>,
 456    capture_actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 457    // Entity Types -> { Action Types -> Action Handlers }
 458    actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 459    // Action Types -> Action Handlers
 460    global_actions: HashMap<TypeId, Box<GlobalActionCallback>>,
 461    keystroke_matcher: KeymapMatcher,
 462    next_entity_id: usize,
 463    next_window_id: usize,
 464    next_subscription_id: usize,
 465    frame_count: usize,
 466
 467    subscriptions: CallbackCollection<usize, SubscriptionCallback>,
 468    global_subscriptions: CallbackCollection<TypeId, GlobalSubscriptionCallback>,
 469    observations: CallbackCollection<usize, ObservationCallback>,
 470    global_observations: CallbackCollection<TypeId, GlobalObservationCallback>,
 471    focus_observations: CallbackCollection<usize, FocusObservationCallback>,
 472    release_observations: CallbackCollection<usize, ReleaseObservationCallback>,
 473    action_dispatch_observations: CallbackCollection<(), ActionObservationCallback>,
 474    window_activation_observations: CallbackCollection<usize, WindowActivationCallback>,
 475    window_fullscreen_observations: CallbackCollection<usize, WindowFullscreenCallback>,
 476    window_bounds_observations: CallbackCollection<usize, WindowBoundsCallback>,
 477    keystroke_observations: CallbackCollection<usize, KeystrokeCallback>,
 478    active_labeled_task_observations: CallbackCollection<(), ActiveLabeledTasksCallback>,
 479
 480    foreground: Rc<executor::Foreground>,
 481    pending_effects: VecDeque<Effect>,
 482    pending_notifications: HashSet<usize>,
 483    pending_global_notifications: HashSet<TypeId>,
 484    pending_flushes: usize,
 485    flushing_effects: bool,
 486    halt_action_dispatch: bool,
 487    next_labeled_task_id: usize,
 488    active_labeled_tasks: BTreeMap<usize, &'static str>,
 489}
 490
 491impl AppContext {
 492    fn new(
 493        foreground: Rc<executor::Foreground>,
 494        background: Arc<executor::Background>,
 495        platform: Arc<dyn platform::Platform>,
 496        foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 497        font_cache: Arc<FontCache>,
 498        ref_counts: RefCounts,
 499        asset_source: impl AssetSource,
 500    ) -> Self {
 501        Self {
 502            models: Default::default(),
 503            views: Default::default(),
 504            windows: Default::default(),
 505            globals: Default::default(),
 506            element_states: Default::default(),
 507            ref_counts: Arc::new(Mutex::new(ref_counts)),
 508            background,
 509
 510            weak_self: None,
 511            font_system: platform.fonts(),
 512            platform,
 513            foreground_platform,
 514            font_cache,
 515            asset_cache: Arc::new(AssetCache::new(asset_source)),
 516            action_deserializers: Default::default(),
 517            capture_actions: Default::default(),
 518            actions: Default::default(),
 519            global_actions: Default::default(),
 520            keystroke_matcher: KeymapMatcher::default(),
 521            next_entity_id: 0,
 522            next_window_id: 0,
 523            next_subscription_id: 0,
 524            frame_count: 0,
 525            subscriptions: Default::default(),
 526            global_subscriptions: Default::default(),
 527            observations: Default::default(),
 528            focus_observations: Default::default(),
 529            release_observations: Default::default(),
 530            global_observations: Default::default(),
 531            window_activation_observations: Default::default(),
 532            window_fullscreen_observations: Default::default(),
 533            window_bounds_observations: Default::default(),
 534            keystroke_observations: Default::default(),
 535            action_dispatch_observations: Default::default(),
 536            active_labeled_task_observations: Default::default(),
 537            foreground,
 538            pending_effects: VecDeque::new(),
 539            pending_notifications: Default::default(),
 540            pending_global_notifications: Default::default(),
 541            pending_flushes: 0,
 542            flushing_effects: false,
 543            halt_action_dispatch: false,
 544            next_labeled_task_id: 0,
 545            active_labeled_tasks: Default::default(),
 546        }
 547    }
 548
 549    pub fn background(&self) -> &Arc<executor::Background> {
 550        &self.background
 551    }
 552
 553    pub fn font_cache(&self) -> &Arc<FontCache> {
 554        &self.font_cache
 555    }
 556
 557    pub fn platform(&self) -> &Arc<dyn Platform> {
 558        &self.platform
 559    }
 560
 561    pub fn has_global<T: 'static>(&self) -> bool {
 562        self.globals.contains_key(&TypeId::of::<T>())
 563    }
 564
 565    pub fn global<T: 'static>(&self) -> &T {
 566        if let Some(global) = self.globals.get(&TypeId::of::<T>()) {
 567            global.downcast_ref().unwrap()
 568        } else {
 569            panic!("no global has been added for {}", type_name::<T>());
 570        }
 571    }
 572
 573    pub fn upgrade(&self) -> App {
 574        App(self.weak_self.as_ref().unwrap().upgrade().unwrap())
 575    }
 576
 577    fn quit(&mut self) {
 578        let mut futures = Vec::new();
 579
 580        self.update(|cx| {
 581            for model_id in cx.models.keys().copied().collect::<Vec<_>>() {
 582                let mut model = cx.models.remove(&model_id).unwrap();
 583                futures.extend(model.app_will_quit(cx));
 584                cx.models.insert(model_id, model);
 585            }
 586
 587            for view_id in cx.views.keys().copied().collect::<Vec<_>>() {
 588                let mut view = cx.views.remove(&view_id).unwrap();
 589                futures.extend(view.app_will_quit(cx));
 590                cx.views.insert(view_id, view);
 591            }
 592        });
 593
 594        self.windows.clear();
 595        self.flush_effects();
 596
 597        let futures = futures::future::join_all(futures);
 598        if self
 599            .background
 600            .block_with_timeout(Duration::from_millis(100), futures)
 601            .is_err()
 602        {
 603            log::error!("timed out waiting on app_will_quit");
 604        }
 605    }
 606
 607    pub fn foreground(&self) -> &Rc<executor::Foreground> {
 608        &self.foreground
 609    }
 610
 611    pub fn deserialize_action(
 612        &self,
 613        name: &str,
 614        argument: Option<&str>,
 615    ) -> Result<Box<dyn Action>> {
 616        let callback = self
 617            .action_deserializers
 618            .get(name)
 619            .ok_or_else(|| anyhow!("unknown action {}", name))?
 620            .1;
 621        callback(argument.unwrap_or("{}"))
 622            .with_context(|| format!("invalid data for action {}", name))
 623    }
 624
 625    pub fn add_action<A, V, F, R>(&mut self, handler: F)
 626    where
 627        A: Action,
 628        V: View,
 629        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> R,
 630    {
 631        self.add_action_internal(handler, false)
 632    }
 633
 634    pub fn capture_action<A, V, F>(&mut self, handler: F)
 635    where
 636        A: Action,
 637        V: View,
 638        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
 639    {
 640        self.add_action_internal(handler, true)
 641    }
 642
 643    fn add_action_internal<A, V, F, R>(&mut self, mut handler: F, capture: bool)
 644    where
 645        A: Action,
 646        V: View,
 647        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> R,
 648    {
 649        let handler = Box::new(
 650            move |view: &mut dyn AnyView,
 651                  action: &dyn Action,
 652                  cx: &mut WindowContext,
 653                  view_id: usize| {
 654                let action = action.as_any().downcast_ref().unwrap();
 655                let mut cx = ViewContext::mutable(cx, view_id);
 656                handler(
 657                    view.as_any_mut()
 658                        .downcast_mut()
 659                        .expect("downcast is type safe"),
 660                    action,
 661                    &mut cx,
 662                );
 663            },
 664        );
 665
 666        self.action_deserializers
 667            .entry(A::qualified_name())
 668            .or_insert((TypeId::of::<A>(), A::from_json_str));
 669
 670        let actions = if capture {
 671            &mut self.capture_actions
 672        } else {
 673            &mut self.actions
 674        };
 675
 676        actions
 677            .entry(TypeId::of::<V>())
 678            .or_default()
 679            .entry(TypeId::of::<A>())
 680            .or_default()
 681            .push(handler);
 682    }
 683
 684    pub fn add_async_action<A, V, F>(&mut self, mut handler: F)
 685    where
 686        A: Action,
 687        V: View,
 688        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> Option<Task<Result<()>>>,
 689    {
 690        self.add_action(move |view, action, cx| {
 691            if let Some(task) = handler(view, action, cx) {
 692                task.detach_and_log_err(cx);
 693            }
 694        })
 695    }
 696
 697    pub fn add_global_action<A, F>(&mut self, mut handler: F)
 698    where
 699        A: Action,
 700        F: 'static + FnMut(&A, &mut AppContext),
 701    {
 702        let handler = Box::new(move |action: &dyn Action, cx: &mut AppContext| {
 703            let action = action.as_any().downcast_ref().unwrap();
 704            handler(action, cx);
 705        });
 706
 707        self.action_deserializers
 708            .entry(A::qualified_name())
 709            .or_insert((TypeId::of::<A>(), A::from_json_str));
 710
 711        if self
 712            .global_actions
 713            .insert(TypeId::of::<A>(), handler)
 714            .is_some()
 715        {
 716            panic!(
 717                "registered multiple global handlers for {}",
 718                type_name::<A>()
 719            );
 720        }
 721    }
 722
 723    pub fn view_ui_name(&self, window_id: usize, view_id: usize) -> Option<&'static str> {
 724        Some(self.views.get(&(window_id, view_id))?.ui_name())
 725    }
 726
 727    pub fn view_type_id(&self, window_id: usize, view_id: usize) -> Option<TypeId> {
 728        self.views
 729            .get(&(window_id, view_id))
 730            .map(|view| view.as_any().type_id())
 731    }
 732
 733    pub fn active_labeled_tasks<'a>(
 734        &'a self,
 735    ) -> impl DoubleEndedIterator<Item = &'static str> + 'a {
 736        self.active_labeled_tasks.values().cloned()
 737    }
 738
 739    pub(crate) fn start_frame(&mut self) {
 740        self.frame_count += 1;
 741    }
 742
 743    pub fn update<T, F: FnOnce(&mut Self) -> T>(&mut self, callback: F) -> T {
 744        self.pending_flushes += 1;
 745        let result = callback(self);
 746        self.flush_effects();
 747        result
 748    }
 749
 750    pub fn read_window<T, F: FnOnce(&WindowContext) -> T>(
 751        &self,
 752        window_id: usize,
 753        callback: F,
 754    ) -> Option<T> {
 755        let window = self.windows.get(&window_id)?;
 756        let window_context = WindowContext::immutable(self, &window, window_id);
 757        Some(callback(&window_context))
 758    }
 759
 760    pub fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 761        &mut self,
 762        window_id: usize,
 763        callback: F,
 764    ) -> Option<T> {
 765        self.update(|app_context| {
 766            let mut window = app_context.windows.remove(&window_id)?;
 767            let mut window_context = WindowContext::mutable(app_context, &mut window, window_id);
 768            let result = callback(&mut window_context);
 769            if !window_context.removed {
 770                app_context.windows.insert(window_id, window);
 771            }
 772            Some(result)
 773        })
 774    }
 775
 776    pub fn update_active_window<T, F: FnOnce(&mut WindowContext) -> T>(
 777        &mut self,
 778        callback: F,
 779    ) -> Option<T> {
 780        self.platform
 781            .main_window_id()
 782            .and_then(|id| self.update_window(id, callback))
 783    }
 784
 785    pub fn prompt_for_paths(
 786        &self,
 787        options: PathPromptOptions,
 788    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
 789        self.foreground_platform.prompt_for_paths(options)
 790    }
 791
 792    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
 793        self.foreground_platform.prompt_for_new_path(directory)
 794    }
 795
 796    pub fn reveal_path(&self, path: &Path) {
 797        self.foreground_platform.reveal_path(path)
 798    }
 799
 800    pub fn emit_global<E: Any>(&mut self, payload: E) {
 801        self.pending_effects.push_back(Effect::GlobalEvent {
 802            payload: Box::new(payload),
 803        });
 804    }
 805
 806    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 807    where
 808        E: Entity,
 809        E::Event: 'static,
 810        H: Handle<E>,
 811        F: 'static + FnMut(H, &E::Event, &mut Self),
 812    {
 813        self.subscribe_internal(handle, move |handle, event, cx| {
 814            callback(handle, event, cx);
 815            true
 816        })
 817    }
 818
 819    pub fn subscribe_global<E, F>(&mut self, mut callback: F) -> Subscription
 820    where
 821        E: Any,
 822        F: 'static + FnMut(&E, &mut Self),
 823    {
 824        let subscription_id = post_inc(&mut self.next_subscription_id);
 825        let type_id = TypeId::of::<E>();
 826        self.pending_effects.push_back(Effect::GlobalSubscription {
 827            type_id,
 828            subscription_id,
 829            callback: Box::new(move |payload, cx| {
 830                let payload = payload.downcast_ref().expect("downcast is type safe");
 831                callback(payload, cx)
 832            }),
 833        });
 834        Subscription::GlobalSubscription(
 835            self.global_subscriptions
 836                .subscribe(type_id, subscription_id),
 837        )
 838    }
 839
 840    pub fn observe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 841    where
 842        E: Entity,
 843        E::Event: 'static,
 844        H: Handle<E>,
 845        F: 'static + FnMut(H, &mut Self),
 846    {
 847        self.observe_internal(handle, move |handle, cx| {
 848            callback(handle, cx);
 849            true
 850        })
 851    }
 852
 853    fn subscribe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 854    where
 855        E: Entity,
 856        E::Event: 'static,
 857        H: Handle<E>,
 858        F: 'static + FnMut(H, &E::Event, &mut Self) -> bool,
 859    {
 860        let subscription_id = post_inc(&mut self.next_subscription_id);
 861        let emitter = handle.downgrade();
 862        self.pending_effects.push_back(Effect::Subscription {
 863            entity_id: handle.id(),
 864            subscription_id,
 865            callback: Box::new(move |payload, cx| {
 866                if let Some(emitter) = H::upgrade_from(&emitter, cx) {
 867                    let payload = payload.downcast_ref().expect("downcast is type safe");
 868                    callback(emitter, payload, cx)
 869                } else {
 870                    false
 871                }
 872            }),
 873        });
 874        Subscription::Subscription(self.subscriptions.subscribe(handle.id(), subscription_id))
 875    }
 876
 877    fn observe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 878    where
 879        E: Entity,
 880        E::Event: 'static,
 881        H: Handle<E>,
 882        F: 'static + FnMut(H, &mut Self) -> bool,
 883    {
 884        let subscription_id = post_inc(&mut self.next_subscription_id);
 885        let observed = handle.downgrade();
 886        let entity_id = handle.id();
 887        self.pending_effects.push_back(Effect::Observation {
 888            entity_id,
 889            subscription_id,
 890            callback: Box::new(move |cx| {
 891                if let Some(observed) = H::upgrade_from(&observed, cx) {
 892                    callback(observed, cx)
 893                } else {
 894                    false
 895                }
 896            }),
 897        });
 898        Subscription::Observation(self.observations.subscribe(entity_id, subscription_id))
 899    }
 900
 901    fn observe_focus<F, V>(&mut self, handle: &ViewHandle<V>, mut callback: F) -> Subscription
 902    where
 903        F: 'static + FnMut(ViewHandle<V>, bool, &mut WindowContext) -> bool,
 904        V: View,
 905    {
 906        let subscription_id = post_inc(&mut self.next_subscription_id);
 907        let observed = handle.downgrade();
 908        let view_id = handle.id();
 909
 910        self.pending_effects.push_back(Effect::FocusObservation {
 911            view_id,
 912            subscription_id,
 913            callback: Box::new(move |focused, cx| {
 914                if let Some(observed) = observed.upgrade(cx) {
 915                    callback(observed, focused, cx)
 916                } else {
 917                    false
 918                }
 919            }),
 920        });
 921        Subscription::FocusObservation(self.focus_observations.subscribe(view_id, subscription_id))
 922    }
 923
 924    pub fn observe_global<G, F>(&mut self, mut observe: F) -> Subscription
 925    where
 926        G: Any,
 927        F: 'static + FnMut(&mut AppContext),
 928    {
 929        let type_id = TypeId::of::<G>();
 930        let id = post_inc(&mut self.next_subscription_id);
 931
 932        self.global_observations.add_callback(
 933            type_id,
 934            id,
 935            Box::new(move |cx: &mut AppContext| observe(cx)),
 936        );
 937        Subscription::GlobalObservation(self.global_observations.subscribe(type_id, id))
 938    }
 939
 940    pub fn observe_default_global<G, F>(&mut self, observe: F) -> Subscription
 941    where
 942        G: Any + Default,
 943        F: 'static + FnMut(&mut AppContext),
 944    {
 945        if !self.has_global::<G>() {
 946            self.set_global(G::default());
 947        }
 948        self.observe_global::<G, F>(observe)
 949    }
 950
 951    pub fn observe_release<E, H, F>(&mut self, handle: &H, callback: F) -> Subscription
 952    where
 953        E: Entity,
 954        E::Event: 'static,
 955        H: Handle<E>,
 956        F: 'static + FnOnce(&E, &mut Self),
 957    {
 958        let id = post_inc(&mut self.next_subscription_id);
 959        let mut callback = Some(callback);
 960        self.release_observations.add_callback(
 961            handle.id(),
 962            id,
 963            Box::new(move |released, cx| {
 964                let released = released.downcast_ref().unwrap();
 965                if let Some(callback) = callback.take() {
 966                    callback(released, cx)
 967                }
 968            }),
 969        );
 970        Subscription::ReleaseObservation(self.release_observations.subscribe(handle.id(), id))
 971    }
 972
 973    pub fn observe_actions<F>(&mut self, callback: F) -> Subscription
 974    where
 975        F: 'static + FnMut(TypeId, &mut AppContext),
 976    {
 977        let subscription_id = post_inc(&mut self.next_subscription_id);
 978        self.action_dispatch_observations
 979            .add_callback((), subscription_id, Box::new(callback));
 980        Subscription::ActionObservation(
 981            self.action_dispatch_observations
 982                .subscribe((), subscription_id),
 983        )
 984    }
 985
 986    fn observe_active_labeled_tasks<F>(&mut self, callback: F) -> Subscription
 987    where
 988        F: 'static + FnMut(&mut AppContext) -> bool,
 989    {
 990        let subscription_id = post_inc(&mut self.next_subscription_id);
 991        self.active_labeled_task_observations
 992            .add_callback((), subscription_id, Box::new(callback));
 993        Subscription::ActiveLabeledTasksObservation(
 994            self.active_labeled_task_observations
 995                .subscribe((), subscription_id),
 996        )
 997    }
 998
 999    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut AppContext)) {
1000        self.pending_effects.push_back(Effect::Deferred {
1001            callback: Box::new(callback),
1002            after_window_update: false,
1003        })
1004    }
1005
1006    pub fn after_window_update(&mut self, callback: impl 'static + FnOnce(&mut AppContext)) {
1007        self.pending_effects.push_back(Effect::Deferred {
1008            callback: Box::new(callback),
1009            after_window_update: true,
1010        })
1011    }
1012
1013    fn notify_model(&mut self, model_id: usize) {
1014        if self.pending_notifications.insert(model_id) {
1015            self.pending_effects
1016                .push_back(Effect::ModelNotification { model_id });
1017        }
1018    }
1019
1020    fn notify_view(&mut self, window_id: usize, view_id: usize) {
1021        if self.pending_notifications.insert(view_id) {
1022            self.pending_effects
1023                .push_back(Effect::ViewNotification { window_id, view_id });
1024        }
1025    }
1026
1027    fn notify_global(&mut self, type_id: TypeId) {
1028        if self.pending_global_notifications.insert(type_id) {
1029            self.pending_effects
1030                .push_back(Effect::GlobalNotification { type_id });
1031        }
1032    }
1033
1034    pub fn all_action_names<'a>(&'a self) -> impl Iterator<Item = &'static str> + 'a {
1035        self.action_deserializers.keys().copied()
1036    }
1037
1038    pub fn is_action_available(&self, action: &dyn Action) -> bool {
1039        let mut available_in_window = false;
1040        let action_type = action.as_any().type_id();
1041        if let Some(window_id) = self.platform.main_window_id() {
1042            available_in_window = self
1043                .read_window(window_id, |cx| {
1044                    if let Some(focused_view_id) = cx.focused_view_id() {
1045                        for view_id in cx.ancestors(focused_view_id) {
1046                            if let Some(view) = cx.views.get(&(window_id, view_id)) {
1047                                let view_type = view.as_any().type_id();
1048                                if let Some(actions) = cx.actions.get(&view_type) {
1049                                    if actions.contains_key(&action_type) {
1050                                        return true;
1051                                    }
1052                                }
1053                            }
1054                        }
1055                    }
1056                    false
1057                })
1058                .unwrap_or(false);
1059        }
1060        available_in_window || self.global_actions.contains_key(&action_type)
1061    }
1062
1063    fn actions_mut(
1064        &mut self,
1065        capture_phase: bool,
1066    ) -> &mut HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>> {
1067        if capture_phase {
1068            &mut self.capture_actions
1069        } else {
1070            &mut self.actions
1071        }
1072    }
1073
1074    fn dispatch_global_action_any(&mut self, action: &dyn Action) -> bool {
1075        self.update(|this| {
1076            if let Some((name, mut handler)) = this.global_actions.remove_entry(&action.id()) {
1077                handler(action, this);
1078                this.global_actions.insert(name, handler);
1079                true
1080            } else {
1081                false
1082            }
1083        })
1084    }
1085
1086    pub fn add_bindings<T: IntoIterator<Item = Binding>>(&mut self, bindings: T) {
1087        self.keystroke_matcher.add_bindings(bindings);
1088    }
1089
1090    pub fn clear_bindings(&mut self) {
1091        self.keystroke_matcher.clear_bindings();
1092    }
1093
1094    pub fn default_global<T: 'static + Default>(&mut self) -> &T {
1095        let type_id = TypeId::of::<T>();
1096        self.update(|this| {
1097            if let Entry::Vacant(entry) = this.globals.entry(type_id) {
1098                entry.insert(Box::new(T::default()));
1099                this.notify_global(type_id);
1100            }
1101        });
1102        self.globals.get(&type_id).unwrap().downcast_ref().unwrap()
1103    }
1104
1105    pub fn set_global<T: 'static>(&mut self, state: T) {
1106        self.update(|this| {
1107            let type_id = TypeId::of::<T>();
1108            this.globals.insert(type_id, Box::new(state));
1109            this.notify_global(type_id);
1110        });
1111    }
1112
1113    pub fn update_default_global<T, F, U>(&mut self, update: F) -> U
1114    where
1115        T: 'static + Default,
1116        F: FnOnce(&mut T, &mut AppContext) -> U,
1117    {
1118        self.update(|mut this| {
1119            Self::update_default_global_internal(&mut this, |global, cx| update(global, cx))
1120        })
1121    }
1122
1123    fn update_default_global_internal<C, T, F, U>(this: &mut C, update: F) -> U
1124    where
1125        C: DerefMut<Target = AppContext>,
1126        T: 'static + Default,
1127        F: FnOnce(&mut T, &mut C) -> U,
1128    {
1129        let type_id = TypeId::of::<T>();
1130        let mut state = this
1131            .globals
1132            .remove(&type_id)
1133            .unwrap_or_else(|| Box::new(T::default()));
1134        let result = update(state.downcast_mut().unwrap(), this);
1135        this.globals.insert(type_id, state);
1136        this.notify_global(type_id);
1137        result
1138    }
1139
1140    pub fn update_global<T, F, U>(&mut self, update: F) -> U
1141    where
1142        T: 'static,
1143        F: FnOnce(&mut T, &mut AppContext) -> U,
1144    {
1145        self.update(|mut this| {
1146            Self::update_global_internal(&mut this, |global, cx| update(global, cx))
1147        })
1148    }
1149
1150    fn update_global_internal<C, T, F, U>(this: &mut C, update: F) -> U
1151    where
1152        C: DerefMut<Target = AppContext>,
1153        T: 'static,
1154        F: FnOnce(&mut T, &mut C) -> U,
1155    {
1156        let type_id = TypeId::of::<T>();
1157        if let Some(mut state) = this.globals.remove(&type_id) {
1158            let result = update(state.downcast_mut().unwrap(), this);
1159            this.globals.insert(type_id, state);
1160            this.notify_global(type_id);
1161            result
1162        } else {
1163            panic!("No global added for {}", std::any::type_name::<T>());
1164        }
1165    }
1166
1167    pub fn clear_globals(&mut self) {
1168        self.globals.clear();
1169    }
1170
1171    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
1172    where
1173        T: Entity,
1174        F: FnOnce(&mut ModelContext<T>) -> T,
1175    {
1176        self.update(|this| {
1177            let model_id = post_inc(&mut this.next_entity_id);
1178            let handle = ModelHandle::new(model_id, &this.ref_counts);
1179            let mut cx = ModelContext::new(this, model_id);
1180            let model = build_model(&mut cx);
1181            this.models.insert(model_id, Box::new(model));
1182            handle
1183        })
1184    }
1185
1186    pub fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
1187        if let Some(model) = self.models.get(&handle.model_id) {
1188            model
1189                .as_any()
1190                .downcast_ref()
1191                .expect("downcast is type safe")
1192        } else {
1193            panic!("circular model reference");
1194        }
1195    }
1196
1197    fn update_model<T: Entity, V>(
1198        &mut self,
1199        handle: &ModelHandle<T>,
1200        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> V,
1201    ) -> V {
1202        if let Some(mut model) = self.models.remove(&handle.model_id) {
1203            self.update(|this| {
1204                let mut cx = ModelContext::new(this, handle.model_id);
1205                let result = update(
1206                    model
1207                        .as_any_mut()
1208                        .downcast_mut()
1209                        .expect("downcast is type safe"),
1210                    &mut cx,
1211                );
1212                this.models.insert(handle.model_id, model);
1213                result
1214            })
1215        } else {
1216            panic!("circular model update");
1217        }
1218    }
1219
1220    fn upgrade_model_handle<T: Entity>(
1221        &self,
1222        handle: &WeakModelHandle<T>,
1223    ) -> Option<ModelHandle<T>> {
1224        if self.ref_counts.lock().is_entity_alive(handle.model_id) {
1225            Some(ModelHandle::new(handle.model_id, &self.ref_counts))
1226        } else {
1227            None
1228        }
1229    }
1230
1231    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
1232        self.ref_counts.lock().is_entity_alive(handle.model_id)
1233    }
1234
1235    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
1236        if self.ref_counts.lock().is_entity_alive(handle.model_id) {
1237            Some(AnyModelHandle::new(
1238                handle.model_id,
1239                handle.model_type,
1240                self.ref_counts.clone(),
1241            ))
1242        } else {
1243            None
1244        }
1245    }
1246
1247    pub fn add_window<V, F>(
1248        &mut self,
1249        window_options: WindowOptions,
1250        build_root_view: F,
1251    ) -> (usize, ViewHandle<V>)
1252    where
1253        V: View,
1254        F: FnOnce(&mut ViewContext<V>) -> V,
1255    {
1256        self.update(|this| {
1257            let window_id = post_inc(&mut this.next_window_id);
1258            let platform_window =
1259                this.platform
1260                    .open_window(window_id, window_options, this.foreground.clone());
1261            let window = this.build_window(window_id, platform_window, build_root_view);
1262            let root_view = window.root_view().clone().downcast::<V>().unwrap();
1263            this.windows.insert(window_id, window);
1264            (window_id, root_view)
1265        })
1266    }
1267
1268    pub fn add_status_bar_item<V, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<V>)
1269    where
1270        V: View,
1271        F: FnOnce(&mut ViewContext<V>) -> V,
1272    {
1273        self.update(|this| {
1274            let window_id = post_inc(&mut this.next_window_id);
1275            let platform_window = this.platform.add_status_item(window_id);
1276            let window = this.build_window(window_id, platform_window, build_root_view);
1277            let root_view = window.root_view().clone().downcast::<V>().unwrap();
1278
1279            this.windows.insert(window_id, window);
1280            this.update_window(window_id, |cx| {
1281                root_view.update(cx, |view, cx| view.focus_in(cx.handle().into_any(), cx))
1282            });
1283
1284            (window_id, root_view)
1285        })
1286    }
1287
1288    pub fn build_window<V, F>(
1289        &mut self,
1290        window_id: usize,
1291        mut platform_window: Box<dyn platform::Window>,
1292        build_root_view: F,
1293    ) -> Window
1294    where
1295        V: View,
1296        F: FnOnce(&mut ViewContext<V>) -> V,
1297    {
1298        {
1299            let mut app = self.upgrade();
1300
1301            platform_window.on_event(Box::new(move |event| {
1302                app.update_window(window_id, |cx| {
1303                    if let Event::KeyDown(KeyDownEvent { keystroke, .. }) = &event {
1304                        if cx.dispatch_keystroke(keystroke) {
1305                            return true;
1306                        }
1307                    }
1308
1309                    cx.dispatch_event(event, false)
1310                })
1311                .unwrap_or(false)
1312            }));
1313        }
1314
1315        {
1316            let mut app = self.upgrade();
1317            platform_window.on_active_status_change(Box::new(move |is_active| {
1318                app.update(|cx| cx.window_changed_active_status(window_id, is_active))
1319            }));
1320        }
1321
1322        {
1323            let mut app = self.upgrade();
1324            platform_window.on_resize(Box::new(move || {
1325                app.update(|cx| cx.window_was_resized(window_id))
1326            }));
1327        }
1328
1329        {
1330            let mut app = self.upgrade();
1331            platform_window.on_moved(Box::new(move || {
1332                app.update(|cx| cx.window_was_moved(window_id))
1333            }));
1334        }
1335
1336        {
1337            let mut app = self.upgrade();
1338            platform_window.on_fullscreen(Box::new(move |is_fullscreen| {
1339                app.update(|cx| cx.window_was_fullscreen_changed(window_id, is_fullscreen))
1340            }));
1341        }
1342
1343        {
1344            let mut app = self.upgrade();
1345            platform_window.on_close(Box::new(move || {
1346                app.update(|cx| cx.update_window(window_id, |cx| cx.remove_window()));
1347            }));
1348        }
1349
1350        {
1351            let mut app = self.upgrade();
1352            platform_window
1353                .on_appearance_changed(Box::new(move || app.update(|cx| cx.refresh_windows())));
1354        }
1355
1356        platform_window.set_input_handler(Box::new(WindowInputHandler {
1357            app: self.upgrade().0,
1358            window_id,
1359        }));
1360
1361        let mut window = Window::new(window_id, platform_window, self, build_root_view);
1362        let mut cx = WindowContext::mutable(self, &mut window, window_id);
1363        cx.layout(false).expect("initial layout should not error");
1364        let scene = cx.paint().expect("initial paint should not error");
1365        window.platform_window.present_scene(scene);
1366        window
1367    }
1368
1369    pub fn replace_root_view<V, F>(
1370        &mut self,
1371        window_id: usize,
1372        build_root_view: F,
1373    ) -> Option<ViewHandle<V>>
1374    where
1375        V: View,
1376        F: FnOnce(&mut ViewContext<V>) -> V,
1377    {
1378        self.update_window(window_id, |cx| cx.replace_root_view(build_root_view))
1379    }
1380
1381    pub fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
1382        if let Some(view) = self.views.get(&(handle.window_id, handle.view_id)) {
1383            view.as_any().downcast_ref().expect("downcast is type safe")
1384        } else {
1385            panic!("circular view reference for type {}", type_name::<T>());
1386        }
1387    }
1388
1389    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
1390        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
1391            Some(ViewHandle::new(
1392                handle.window_id,
1393                handle.view_id,
1394                &self.ref_counts,
1395            ))
1396        } else {
1397            None
1398        }
1399    }
1400
1401    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
1402        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
1403            Some(AnyViewHandle::new(
1404                handle.window_id,
1405                handle.view_id,
1406                handle.view_type,
1407                self.ref_counts.clone(),
1408            ))
1409        } else {
1410            None
1411        }
1412    }
1413
1414    fn remove_dropped_entities(&mut self) {
1415        loop {
1416            let (dropped_models, dropped_views, dropped_element_states) =
1417                self.ref_counts.lock().take_dropped();
1418            if dropped_models.is_empty()
1419                && dropped_views.is_empty()
1420                && dropped_element_states.is_empty()
1421            {
1422                break;
1423            }
1424
1425            for model_id in dropped_models {
1426                self.subscriptions.remove(model_id);
1427                self.observations.remove(model_id);
1428                let mut model = self.models.remove(&model_id).unwrap();
1429                model.release(self);
1430                self.pending_effects
1431                    .push_back(Effect::ModelRelease { model_id, model });
1432            }
1433
1434            for (window_id, view_id) in dropped_views {
1435                self.subscriptions.remove(view_id);
1436                self.observations.remove(view_id);
1437                let mut view = self.views.remove(&(window_id, view_id)).unwrap();
1438                view.release(self);
1439                let change_focus_to = self.windows.get_mut(&window_id).and_then(|window| {
1440                    window.parents.remove(&view_id);
1441                    window
1442                        .invalidation
1443                        .get_or_insert_with(Default::default)
1444                        .removed
1445                        .push(view_id);
1446                    if window.focused_view_id == Some(view_id) {
1447                        Some(window.root_view().id())
1448                    } else {
1449                        None
1450                    }
1451                });
1452
1453                if let Some(view_id) = change_focus_to {
1454                    self.pending_effects.push_back(Effect::Focus {
1455                        window_id,
1456                        view_id: Some(view_id),
1457                    });
1458                }
1459
1460                self.pending_effects
1461                    .push_back(Effect::ViewRelease { view_id, view });
1462            }
1463
1464            for key in dropped_element_states {
1465                self.element_states.remove(&key);
1466            }
1467        }
1468    }
1469
1470    fn flush_effects(&mut self) {
1471        self.pending_flushes = self.pending_flushes.saturating_sub(1);
1472        let mut after_window_update_callbacks = Vec::new();
1473
1474        if !self.flushing_effects && self.pending_flushes == 0 {
1475            self.flushing_effects = true;
1476
1477            let mut refreshing = false;
1478            let mut updated_windows = HashSet::default();
1479            let mut focused_views = HashMap::default();
1480            loop {
1481                self.remove_dropped_entities();
1482                if let Some(effect) = self.pending_effects.pop_front() {
1483                    match effect {
1484                        Effect::Subscription {
1485                            entity_id,
1486                            subscription_id,
1487                            callback,
1488                        } => self
1489                            .subscriptions
1490                            .add_callback(entity_id, subscription_id, callback),
1491
1492                        Effect::Event { entity_id, payload } => {
1493                            let mut subscriptions = self.subscriptions.clone();
1494                            subscriptions
1495                                .emit(entity_id, |callback| callback(payload.as_ref(), self))
1496                        }
1497
1498                        Effect::GlobalSubscription {
1499                            type_id,
1500                            subscription_id,
1501                            callback,
1502                        } => self.global_subscriptions.add_callback(
1503                            type_id,
1504                            subscription_id,
1505                            callback,
1506                        ),
1507
1508                        Effect::GlobalEvent { payload } => self.emit_global_event(payload),
1509
1510                        Effect::Observation {
1511                            entity_id,
1512                            subscription_id,
1513                            callback,
1514                        } => self
1515                            .observations
1516                            .add_callback(entity_id, subscription_id, callback),
1517
1518                        Effect::ModelNotification { model_id } => {
1519                            let mut observations = self.observations.clone();
1520                            observations.emit(model_id, |callback| callback(self));
1521                        }
1522
1523                        Effect::ViewNotification { window_id, view_id } => {
1524                            self.handle_view_notification_effect(window_id, view_id)
1525                        }
1526
1527                        Effect::GlobalNotification { type_id } => {
1528                            let mut subscriptions = self.global_observations.clone();
1529                            subscriptions.emit(type_id, |callback| {
1530                                callback(self);
1531                                true
1532                            });
1533                        }
1534
1535                        Effect::Deferred {
1536                            callback,
1537                            after_window_update,
1538                        } => {
1539                            if after_window_update {
1540                                after_window_update_callbacks.push(callback);
1541                            } else {
1542                                callback(self)
1543                            }
1544                        }
1545
1546                        Effect::ModelRelease { model_id, model } => {
1547                            self.handle_entity_release_effect(model_id, model.as_any())
1548                        }
1549
1550                        Effect::ViewRelease { view_id, view } => {
1551                            self.handle_entity_release_effect(view_id, view.as_any())
1552                        }
1553
1554                        Effect::Focus { window_id, view_id } => {
1555                            focused_views.insert(window_id, view_id);
1556                        }
1557
1558                        Effect::FocusObservation {
1559                            view_id,
1560                            subscription_id,
1561                            callback,
1562                        } => {
1563                            self.focus_observations.add_callback(
1564                                view_id,
1565                                subscription_id,
1566                                callback,
1567                            );
1568                        }
1569
1570                        Effect::ResizeWindow { window_id } => {
1571                            if let Some(window) = self.windows.get_mut(&window_id) {
1572                                window
1573                                    .invalidation
1574                                    .get_or_insert(WindowInvalidation::default());
1575                            }
1576                            self.handle_window_moved(window_id);
1577                        }
1578
1579                        Effect::MoveWindow { window_id } => {
1580                            self.handle_window_moved(window_id);
1581                        }
1582
1583                        Effect::WindowActivationObservation {
1584                            window_id,
1585                            subscription_id,
1586                            callback,
1587                        } => self.window_activation_observations.add_callback(
1588                            window_id,
1589                            subscription_id,
1590                            callback,
1591                        ),
1592
1593                        Effect::ActivateWindow {
1594                            window_id,
1595                            is_active,
1596                        } => self.handle_window_activation_effect(window_id, is_active),
1597
1598                        Effect::WindowFullscreenObservation {
1599                            window_id,
1600                            subscription_id,
1601                            callback,
1602                        } => self.window_fullscreen_observations.add_callback(
1603                            window_id,
1604                            subscription_id,
1605                            callback,
1606                        ),
1607
1608                        Effect::FullscreenWindow {
1609                            window_id,
1610                            is_fullscreen,
1611                        } => self.handle_fullscreen_effect(window_id, is_fullscreen),
1612
1613                        Effect::WindowBoundsObservation {
1614                            window_id,
1615                            subscription_id,
1616                            callback,
1617                        } => self.window_bounds_observations.add_callback(
1618                            window_id,
1619                            subscription_id,
1620                            callback,
1621                        ),
1622
1623                        Effect::RefreshWindows => {
1624                            refreshing = true;
1625                        }
1626
1627                        Effect::ActionDispatchNotification { action_id } => {
1628                            self.handle_action_dispatch_notification_effect(action_id)
1629                        }
1630                        Effect::WindowShouldCloseSubscription {
1631                            window_id,
1632                            callback,
1633                        } => {
1634                            self.handle_window_should_close_subscription_effect(window_id, callback)
1635                        }
1636                        Effect::Keystroke {
1637                            window_id,
1638                            keystroke,
1639                            handled_by,
1640                            result,
1641                        } => self.handle_keystroke_effect(window_id, keystroke, handled_by, result),
1642                        Effect::ActiveLabeledTasksChanged => {
1643                            self.handle_active_labeled_tasks_changed_effect()
1644                        }
1645                        Effect::ActiveLabeledTasksObservation {
1646                            subscription_id,
1647                            callback,
1648                        } => self.active_labeled_task_observations.add_callback(
1649                            (),
1650                            subscription_id,
1651                            callback,
1652                        ),
1653                    }
1654                    self.pending_notifications.clear();
1655                } else {
1656                    for window_id in self.windows.keys().cloned().collect::<Vec<_>>() {
1657                        self.update_window(window_id, |cx| {
1658                            let invalidation = if refreshing {
1659                                let mut invalidation =
1660                                    cx.window.invalidation.take().unwrap_or_default();
1661                                invalidation
1662                                    .updated
1663                                    .extend(cx.window.rendered_views.keys().copied());
1664                                Some(invalidation)
1665                            } else {
1666                                cx.window.invalidation.take()
1667                            };
1668
1669                            if let Some(invalidation) = invalidation {
1670                                let appearance = cx.window.platform_window.appearance();
1671                                cx.invalidate(invalidation, appearance);
1672                                if cx.layout(refreshing).log_err().is_some() {
1673                                    updated_windows.insert(window_id);
1674                                }
1675                            }
1676                        });
1677                    }
1678
1679                    for (window_id, view_id) in focused_views.drain() {
1680                        self.handle_focus_effect(window_id, view_id);
1681                    }
1682
1683                    if self.pending_effects.is_empty() {
1684                        for callback in after_window_update_callbacks.drain(..) {
1685                            callback(self);
1686                        }
1687
1688                        for window_id in updated_windows.drain() {
1689                            self.update_window(window_id, |cx| {
1690                                if let Some(scene) = cx.paint().log_err() {
1691                                    cx.window.platform_window.present_scene(scene);
1692                                }
1693                            });
1694                        }
1695
1696                        if self.pending_effects.is_empty() {
1697                            self.flushing_effects = false;
1698                            self.pending_notifications.clear();
1699                            self.pending_global_notifications.clear();
1700                            break;
1701                        }
1702                    }
1703
1704                    refreshing = false;
1705                }
1706            }
1707        }
1708    }
1709
1710    fn window_was_resized(&mut self, window_id: usize) {
1711        self.pending_effects
1712            .push_back(Effect::ResizeWindow { window_id });
1713    }
1714
1715    fn window_was_moved(&mut self, window_id: usize) {
1716        self.pending_effects
1717            .push_back(Effect::MoveWindow { window_id });
1718    }
1719
1720    fn window_was_fullscreen_changed(&mut self, window_id: usize, is_fullscreen: bool) {
1721        self.pending_effects.push_back(Effect::FullscreenWindow {
1722            window_id,
1723            is_fullscreen,
1724        });
1725    }
1726
1727    fn window_changed_active_status(&mut self, window_id: usize, is_active: bool) {
1728        self.pending_effects.push_back(Effect::ActivateWindow {
1729            window_id,
1730            is_active,
1731        });
1732    }
1733
1734    fn keystroke(
1735        &mut self,
1736        window_id: usize,
1737        keystroke: Keystroke,
1738        handled_by: Option<Box<dyn Action>>,
1739        result: MatchResult,
1740    ) {
1741        self.pending_effects.push_back(Effect::Keystroke {
1742            window_id,
1743            keystroke,
1744            handled_by,
1745            result,
1746        });
1747    }
1748
1749    pub fn refresh_windows(&mut self) {
1750        self.pending_effects.push_back(Effect::RefreshWindows);
1751    }
1752
1753    fn emit_global_event(&mut self, payload: Box<dyn Any>) {
1754        let type_id = (&*payload).type_id();
1755
1756        let mut subscriptions = self.global_subscriptions.clone();
1757        subscriptions.emit(type_id, |callback| {
1758            callback(payload.as_ref(), self);
1759            true //Always alive
1760        });
1761    }
1762
1763    fn handle_view_notification_effect(
1764        &mut self,
1765        observed_window_id: usize,
1766        observed_view_id: usize,
1767    ) {
1768        if self
1769            .views
1770            .contains_key(&(observed_window_id, observed_view_id))
1771        {
1772            if let Some(window) = self.windows.get_mut(&observed_window_id) {
1773                window
1774                    .invalidation
1775                    .get_or_insert_with(Default::default)
1776                    .updated
1777                    .insert(observed_view_id);
1778            }
1779
1780            let mut observations = self.observations.clone();
1781            observations.emit(observed_view_id, |callback| callback(self));
1782        }
1783    }
1784
1785    fn handle_entity_release_effect(&mut self, entity_id: usize, entity: &dyn Any) {
1786        self.release_observations
1787            .clone()
1788            .emit(entity_id, |callback| {
1789                callback(entity, self);
1790                // Release observations happen one time. So clear the callback by returning false
1791                false
1792            })
1793    }
1794
1795    fn handle_fullscreen_effect(&mut self, window_id: usize, is_fullscreen: bool) {
1796        self.update_window(window_id, |cx| {
1797            cx.window.is_fullscreen = is_fullscreen;
1798
1799            let mut fullscreen_observations = cx.window_fullscreen_observations.clone();
1800            fullscreen_observations.emit(window_id, |callback| callback(is_fullscreen, cx));
1801
1802            if let Some(uuid) = cx.window_display_uuid() {
1803                let bounds = cx.window_bounds();
1804                let mut bounds_observations = cx.window_bounds_observations.clone();
1805                bounds_observations.emit(window_id, |callback| callback(bounds, uuid, cx));
1806            }
1807
1808            Some(())
1809        });
1810    }
1811
1812    fn handle_keystroke_effect(
1813        &mut self,
1814        window_id: usize,
1815        keystroke: Keystroke,
1816        handled_by: Option<Box<dyn Action>>,
1817        result: MatchResult,
1818    ) {
1819        self.update_window(window_id, |cx| {
1820            let mut observations = cx.keystroke_observations.clone();
1821            observations.emit(window_id, move |callback| {
1822                callback(&keystroke, &result, handled_by.as_ref(), cx)
1823            });
1824        });
1825    }
1826
1827    fn handle_window_activation_effect(&mut self, window_id: usize, active: bool) {
1828        self.update_window(window_id, |cx| {
1829            if cx.window.is_active == active {
1830                return;
1831            }
1832            cx.window.is_active = active;
1833
1834            if let Some(focused_id) = cx.window.focused_view_id {
1835                for view_id in cx.ancestors(focused_id).collect::<Vec<_>>() {
1836                    cx.update_any_view(view_id, |view, cx| {
1837                        if active {
1838                            view.focus_in(focused_id, cx, view_id);
1839                        } else {
1840                            view.focus_out(focused_id, cx, view_id);
1841                        }
1842                    });
1843                }
1844            }
1845
1846            let mut observations = cx.window_activation_observations.clone();
1847            observations.emit(window_id, |callback| callback(active, cx));
1848        });
1849    }
1850
1851    fn handle_focus_effect(&mut self, window_id: usize, mut focused_id: Option<usize>) {
1852        let mut blurred_id = None;
1853        self.update_window(window_id, |cx| {
1854            if cx.window.focused_view_id == focused_id {
1855                focused_id = None;
1856                return;
1857            }
1858            blurred_id = cx.window.focused_view_id;
1859            cx.window.focused_view_id = focused_id;
1860
1861            let blurred_parents = blurred_id
1862                .map(|blurred_id| cx.ancestors(blurred_id).collect::<Vec<_>>())
1863                .unwrap_or_default();
1864            let focused_parents = focused_id
1865                .map(|focused_id| cx.ancestors(focused_id).collect::<Vec<_>>())
1866                .unwrap_or_default();
1867
1868            if let Some(blurred_id) = blurred_id {
1869                for view_id in blurred_parents.iter().copied() {
1870                    if let Some(mut view) = cx.views.remove(&(window_id, view_id)) {
1871                        view.focus_out(blurred_id, cx, view_id);
1872                        cx.views.insert((window_id, view_id), view);
1873                    }
1874                }
1875
1876                let mut subscriptions = cx.focus_observations.clone();
1877                subscriptions.emit(blurred_id, |callback| callback(false, cx));
1878            }
1879
1880            if let Some(focused_id) = focused_id {
1881                for view_id in focused_parents {
1882                    if let Some(mut view) = cx.views.remove(&(window_id, view_id)) {
1883                        view.focus_in(focused_id, cx, view_id);
1884                        cx.views.insert((window_id, view_id), view);
1885                    }
1886                }
1887
1888                let mut subscriptions = cx.focus_observations.clone();
1889                subscriptions.emit(focused_id, |callback| callback(true, cx));
1890            }
1891        });
1892    }
1893
1894    fn handle_action_dispatch_notification_effect(&mut self, action_id: TypeId) {
1895        self.action_dispatch_observations
1896            .clone()
1897            .emit((), |callback| {
1898                callback(action_id, self);
1899                true
1900            });
1901    }
1902
1903    fn handle_window_should_close_subscription_effect(
1904        &mut self,
1905        window_id: usize,
1906        mut callback: WindowShouldCloseSubscriptionCallback,
1907    ) {
1908        let mut app = self.upgrade();
1909        if let Some(window) = self.windows.get_mut(&window_id) {
1910            window
1911                .platform_window
1912                .on_should_close(Box::new(move || app.update(|cx| callback(cx))))
1913        }
1914    }
1915
1916    fn handle_window_moved(&mut self, window_id: usize) {
1917        self.update_window(window_id, |cx| {
1918            if let Some(display) = cx.window_display_uuid() {
1919                let bounds = cx.window_bounds();
1920                cx.window_bounds_observations
1921                    .clone()
1922                    .emit(window_id, move |callback| {
1923                        callback(bounds, display, cx);
1924                        true
1925                    });
1926            }
1927        });
1928    }
1929
1930    fn handle_active_labeled_tasks_changed_effect(&mut self) {
1931        self.active_labeled_task_observations
1932            .clone()
1933            .emit((), move |callback| {
1934                callback(self);
1935                true
1936            });
1937    }
1938
1939    pub fn focus(&mut self, window_id: usize, view_id: Option<usize>) {
1940        self.pending_effects
1941            .push_back(Effect::Focus { window_id, view_id });
1942    }
1943
1944    fn spawn_internal<F, Fut, T>(&mut self, task_name: Option<&'static str>, f: F) -> Task<T>
1945    where
1946        F: FnOnce(AsyncAppContext) -> Fut,
1947        Fut: 'static + Future<Output = T>,
1948        T: 'static,
1949    {
1950        let label_id = task_name.map(|task_name| {
1951            let id = post_inc(&mut self.next_labeled_task_id);
1952            self.active_labeled_tasks.insert(id, task_name);
1953            self.pending_effects
1954                .push_back(Effect::ActiveLabeledTasksChanged);
1955            id
1956        });
1957
1958        let future = f(self.to_async());
1959        let cx = self.to_async();
1960        self.foreground.spawn(async move {
1961            let result = future.await;
1962            let mut cx = cx.0.borrow_mut();
1963
1964            if let Some(completed_label_id) = label_id {
1965                cx.active_labeled_tasks.remove(&completed_label_id);
1966                cx.pending_effects
1967                    .push_back(Effect::ActiveLabeledTasksChanged);
1968            }
1969            cx.flush_effects();
1970            result
1971        })
1972    }
1973
1974    pub fn spawn_labeled<F, Fut, T>(&mut self, task_name: &'static str, f: F) -> Task<T>
1975    where
1976        F: FnOnce(AsyncAppContext) -> Fut,
1977        Fut: 'static + Future<Output = T>,
1978        T: 'static,
1979    {
1980        self.spawn_internal(Some(task_name), f)
1981    }
1982
1983    pub fn spawn<F, Fut, T>(&mut self, f: F) -> Task<T>
1984    where
1985        F: FnOnce(AsyncAppContext) -> Fut,
1986        Fut: 'static + Future<Output = T>,
1987        T: 'static,
1988    {
1989        self.spawn_internal(None, f)
1990    }
1991
1992    pub fn to_async(&self) -> AsyncAppContext {
1993        AsyncAppContext(self.weak_self.as_ref().unwrap().upgrade().unwrap())
1994    }
1995
1996    pub fn write_to_clipboard(&self, item: ClipboardItem) {
1997        self.platform.write_to_clipboard(item);
1998    }
1999
2000    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
2001        self.platform.read_from_clipboard()
2002    }
2003
2004    #[cfg(any(test, feature = "test-support"))]
2005    pub fn leak_detector(&self) -> Arc<Mutex<LeakDetector>> {
2006        self.ref_counts.lock().leak_detector.clone()
2007    }
2008}
2009
2010impl BorrowAppContext for AppContext {
2011    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
2012        f(self)
2013    }
2014
2015    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
2016        f(self)
2017    }
2018}
2019
2020#[derive(Debug)]
2021pub enum ParentId {
2022    View(usize),
2023    Root,
2024}
2025
2026#[derive(Default, Clone)]
2027pub struct WindowInvalidation {
2028    pub updated: HashSet<usize>,
2029    pub removed: Vec<usize>,
2030}
2031
2032pub enum Effect {
2033    Subscription {
2034        entity_id: usize,
2035        subscription_id: usize,
2036        callback: SubscriptionCallback,
2037    },
2038    Event {
2039        entity_id: usize,
2040        payload: Box<dyn Any>,
2041    },
2042    GlobalSubscription {
2043        type_id: TypeId,
2044        subscription_id: usize,
2045        callback: GlobalSubscriptionCallback,
2046    },
2047    GlobalEvent {
2048        payload: Box<dyn Any>,
2049    },
2050    Observation {
2051        entity_id: usize,
2052        subscription_id: usize,
2053        callback: ObservationCallback,
2054    },
2055    ModelNotification {
2056        model_id: usize,
2057    },
2058    ViewNotification {
2059        window_id: usize,
2060        view_id: usize,
2061    },
2062    Deferred {
2063        callback: Box<dyn FnOnce(&mut AppContext)>,
2064        after_window_update: bool,
2065    },
2066    GlobalNotification {
2067        type_id: TypeId,
2068    },
2069    ModelRelease {
2070        model_id: usize,
2071        model: Box<dyn AnyModel>,
2072    },
2073    ViewRelease {
2074        view_id: usize,
2075        view: Box<dyn AnyView>,
2076    },
2077    Focus {
2078        window_id: usize,
2079        view_id: Option<usize>,
2080    },
2081    FocusObservation {
2082        view_id: usize,
2083        subscription_id: usize,
2084        callback: FocusObservationCallback,
2085    },
2086    ResizeWindow {
2087        window_id: usize,
2088    },
2089    MoveWindow {
2090        window_id: usize,
2091    },
2092    ActivateWindow {
2093        window_id: usize,
2094        is_active: bool,
2095    },
2096    WindowActivationObservation {
2097        window_id: usize,
2098        subscription_id: usize,
2099        callback: WindowActivationCallback,
2100    },
2101    FullscreenWindow {
2102        window_id: usize,
2103        is_fullscreen: bool,
2104    },
2105    WindowFullscreenObservation {
2106        window_id: usize,
2107        subscription_id: usize,
2108        callback: WindowFullscreenCallback,
2109    },
2110    WindowBoundsObservation {
2111        window_id: usize,
2112        subscription_id: usize,
2113        callback: WindowBoundsCallback,
2114    },
2115    Keystroke {
2116        window_id: usize,
2117        keystroke: Keystroke,
2118        handled_by: Option<Box<dyn Action>>,
2119        result: MatchResult,
2120    },
2121    RefreshWindows,
2122    ActionDispatchNotification {
2123        action_id: TypeId,
2124    },
2125    WindowShouldCloseSubscription {
2126        window_id: usize,
2127        callback: WindowShouldCloseSubscriptionCallback,
2128    },
2129    ActiveLabeledTasksChanged,
2130    ActiveLabeledTasksObservation {
2131        subscription_id: usize,
2132        callback: ActiveLabeledTasksCallback,
2133    },
2134}
2135
2136impl Debug for Effect {
2137    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2138        match self {
2139            Effect::Subscription {
2140                entity_id,
2141                subscription_id,
2142                ..
2143            } => f
2144                .debug_struct("Effect::Subscribe")
2145                .field("entity_id", entity_id)
2146                .field("subscription_id", subscription_id)
2147                .finish(),
2148            Effect::Event { entity_id, .. } => f
2149                .debug_struct("Effect::Event")
2150                .field("entity_id", entity_id)
2151                .finish(),
2152            Effect::GlobalSubscription {
2153                type_id,
2154                subscription_id,
2155                ..
2156            } => f
2157                .debug_struct("Effect::Subscribe")
2158                .field("type_id", type_id)
2159                .field("subscription_id", subscription_id)
2160                .finish(),
2161            Effect::GlobalEvent { payload, .. } => f
2162                .debug_struct("Effect::GlobalEvent")
2163                .field("type_id", &(&*payload).type_id())
2164                .finish(),
2165            Effect::Observation {
2166                entity_id,
2167                subscription_id,
2168                ..
2169            } => f
2170                .debug_struct("Effect::Observation")
2171                .field("entity_id", entity_id)
2172                .field("subscription_id", subscription_id)
2173                .finish(),
2174            Effect::ModelNotification { model_id } => f
2175                .debug_struct("Effect::ModelNotification")
2176                .field("model_id", model_id)
2177                .finish(),
2178            Effect::ViewNotification { window_id, view_id } => f
2179                .debug_struct("Effect::ViewNotification")
2180                .field("window_id", window_id)
2181                .field("view_id", view_id)
2182                .finish(),
2183            Effect::GlobalNotification { type_id } => f
2184                .debug_struct("Effect::GlobalNotification")
2185                .field("type_id", type_id)
2186                .finish(),
2187            Effect::Deferred { .. } => f.debug_struct("Effect::Deferred").finish(),
2188            Effect::ModelRelease { model_id, .. } => f
2189                .debug_struct("Effect::ModelRelease")
2190                .field("model_id", model_id)
2191                .finish(),
2192            Effect::ViewRelease { view_id, .. } => f
2193                .debug_struct("Effect::ViewRelease")
2194                .field("view_id", view_id)
2195                .finish(),
2196            Effect::Focus { window_id, view_id } => f
2197                .debug_struct("Effect::Focus")
2198                .field("window_id", window_id)
2199                .field("view_id", view_id)
2200                .finish(),
2201            Effect::FocusObservation {
2202                view_id,
2203                subscription_id,
2204                ..
2205            } => f
2206                .debug_struct("Effect::FocusObservation")
2207                .field("view_id", view_id)
2208                .field("subscription_id", subscription_id)
2209                .finish(),
2210            Effect::ActionDispatchNotification { action_id, .. } => f
2211                .debug_struct("Effect::ActionDispatchNotification")
2212                .field("action_id", action_id)
2213                .finish(),
2214            Effect::ResizeWindow { window_id } => f
2215                .debug_struct("Effect::RefreshWindow")
2216                .field("window_id", window_id)
2217                .finish(),
2218            Effect::MoveWindow { window_id } => f
2219                .debug_struct("Effect::MoveWindow")
2220                .field("window_id", window_id)
2221                .finish(),
2222            Effect::WindowActivationObservation {
2223                window_id,
2224                subscription_id,
2225                ..
2226            } => f
2227                .debug_struct("Effect::WindowActivationObservation")
2228                .field("window_id", window_id)
2229                .field("subscription_id", subscription_id)
2230                .finish(),
2231            Effect::ActivateWindow {
2232                window_id,
2233                is_active,
2234            } => f
2235                .debug_struct("Effect::ActivateWindow")
2236                .field("window_id", window_id)
2237                .field("is_active", is_active)
2238                .finish(),
2239            Effect::FullscreenWindow {
2240                window_id,
2241                is_fullscreen,
2242            } => f
2243                .debug_struct("Effect::FullscreenWindow")
2244                .field("window_id", window_id)
2245                .field("is_fullscreen", is_fullscreen)
2246                .finish(),
2247            Effect::WindowFullscreenObservation {
2248                window_id,
2249                subscription_id,
2250                callback: _,
2251            } => f
2252                .debug_struct("Effect::WindowFullscreenObservation")
2253                .field("window_id", window_id)
2254                .field("subscription_id", subscription_id)
2255                .finish(),
2256
2257            Effect::WindowBoundsObservation {
2258                window_id,
2259                subscription_id,
2260                callback: _,
2261            } => f
2262                .debug_struct("Effect::WindowBoundsObservation")
2263                .field("window_id", window_id)
2264                .field("subscription_id", subscription_id)
2265                .finish(),
2266            Effect::RefreshWindows => f.debug_struct("Effect::FullViewRefresh").finish(),
2267            Effect::WindowShouldCloseSubscription { window_id, .. } => f
2268                .debug_struct("Effect::WindowShouldCloseSubscription")
2269                .field("window_id", window_id)
2270                .finish(),
2271            Effect::Keystroke {
2272                window_id,
2273                keystroke,
2274                handled_by,
2275                result,
2276            } => f
2277                .debug_struct("Effect::Keystroke")
2278                .field("window_id", window_id)
2279                .field("keystroke", keystroke)
2280                .field(
2281                    "keystroke",
2282                    &handled_by.as_ref().map(|handled_by| handled_by.name()),
2283                )
2284                .field("result", result)
2285                .finish(),
2286            Effect::ActiveLabeledTasksChanged => {
2287                f.debug_struct("Effect::ActiveLabeledTasksChanged").finish()
2288            }
2289            Effect::ActiveLabeledTasksObservation {
2290                subscription_id,
2291                callback: _,
2292            } => f
2293                .debug_struct("Effect::ActiveLabeledTasksObservation")
2294                .field("subscription_id", subscription_id)
2295                .finish(),
2296        }
2297    }
2298}
2299
2300pub trait AnyModel {
2301    fn as_any(&self) -> &dyn Any;
2302    fn as_any_mut(&mut self) -> &mut dyn Any;
2303    fn release(&mut self, cx: &mut AppContext);
2304    fn app_will_quit(
2305        &mut self,
2306        cx: &mut AppContext,
2307    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
2308}
2309
2310impl<T> AnyModel for T
2311where
2312    T: Entity,
2313{
2314    fn as_any(&self) -> &dyn Any {
2315        self
2316    }
2317
2318    fn as_any_mut(&mut self) -> &mut dyn Any {
2319        self
2320    }
2321
2322    fn release(&mut self, cx: &mut AppContext) {
2323        self.release(cx);
2324    }
2325
2326    fn app_will_quit(
2327        &mut self,
2328        cx: &mut AppContext,
2329    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
2330        self.app_will_quit(cx)
2331    }
2332}
2333
2334pub trait AnyView {
2335    fn as_any(&self) -> &dyn Any;
2336    fn as_any_mut(&mut self) -> &mut dyn Any;
2337    fn release(&mut self, cx: &mut AppContext);
2338    fn app_will_quit(
2339        &mut self,
2340        cx: &mut AppContext,
2341    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
2342    fn ui_name(&self) -> &'static str;
2343    fn render(&mut self, cx: &mut WindowContext, view_id: usize) -> Box<dyn AnyRootElement>;
2344    fn focus_in<'a, 'b>(&mut self, focused_id: usize, cx: &mut WindowContext<'a>, view_id: usize);
2345    fn focus_out(&mut self, focused_id: usize, cx: &mut WindowContext, view_id: usize);
2346    fn key_down(&mut self, event: &KeyDownEvent, cx: &mut WindowContext, view_id: usize) -> bool;
2347    fn key_up(&mut self, event: &KeyUpEvent, cx: &mut WindowContext, view_id: usize) -> bool;
2348    fn modifiers_changed(
2349        &mut self,
2350        event: &ModifiersChangedEvent,
2351        cx: &mut WindowContext,
2352        view_id: usize,
2353    ) -> bool;
2354    fn keymap_context(&self, cx: &AppContext) -> KeymapContext;
2355    fn debug_json(&self, cx: &WindowContext) -> serde_json::Value;
2356
2357    fn text_for_range(&self, range: Range<usize>, cx: &WindowContext) -> Option<String>;
2358    fn selected_text_range(&self, cx: &WindowContext) -> Option<Range<usize>>;
2359    fn marked_text_range(&self, cx: &WindowContext) -> Option<Range<usize>>;
2360    fn unmark_text(&mut self, cx: &mut WindowContext, view_id: usize);
2361    fn replace_text_in_range(
2362        &mut self,
2363        range: Option<Range<usize>>,
2364        text: &str,
2365        cx: &mut WindowContext,
2366        view_id: usize,
2367    );
2368    fn replace_and_mark_text_in_range(
2369        &mut self,
2370        range: Option<Range<usize>>,
2371        new_text: &str,
2372        new_selected_range: Option<Range<usize>>,
2373        cx: &mut WindowContext,
2374        view_id: usize,
2375    );
2376    fn any_handle(&self, window_id: usize, view_id: usize, cx: &AppContext) -> AnyViewHandle {
2377        AnyViewHandle::new(
2378            window_id,
2379            view_id,
2380            self.as_any().type_id(),
2381            cx.ref_counts.clone(),
2382        )
2383    }
2384}
2385
2386impl<V> AnyView for V
2387where
2388    V: View,
2389{
2390    fn as_any(&self) -> &dyn Any {
2391        self
2392    }
2393
2394    fn as_any_mut(&mut self) -> &mut dyn Any {
2395        self
2396    }
2397
2398    fn release(&mut self, cx: &mut AppContext) {
2399        self.release(cx);
2400    }
2401
2402    fn app_will_quit(
2403        &mut self,
2404        cx: &mut AppContext,
2405    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
2406        self.app_will_quit(cx)
2407    }
2408
2409    fn ui_name(&self) -> &'static str {
2410        V::ui_name()
2411    }
2412
2413    fn render(&mut self, cx: &mut WindowContext, view_id: usize) -> Box<dyn AnyRootElement> {
2414        let mut view_context = ViewContext::mutable(cx, view_id);
2415        let element = V::render(self, &mut view_context);
2416        let view = WeakViewHandle::new(cx.window_id, view_id);
2417        Box::new(RootElement::new(element, view))
2418    }
2419
2420    fn focus_in(&mut self, focused_id: usize, cx: &mut WindowContext, view_id: usize) {
2421        let mut cx = ViewContext::mutable(cx, view_id);
2422        let focused_view_handle: AnyViewHandle = if view_id == focused_id {
2423            cx.handle().into_any()
2424        } else {
2425            let focused_type = cx
2426                .views
2427                .get(&(cx.window_id, focused_id))
2428                .unwrap()
2429                .as_any()
2430                .type_id();
2431            AnyViewHandle::new(
2432                cx.window_id,
2433                focused_id,
2434                focused_type,
2435                cx.ref_counts.clone(),
2436            )
2437        };
2438        View::focus_in(self, focused_view_handle, &mut cx);
2439    }
2440
2441    fn focus_out(&mut self, blurred_id: usize, cx: &mut WindowContext, view_id: usize) {
2442        let mut cx = ViewContext::mutable(cx, view_id);
2443        let blurred_view_handle: AnyViewHandle = if view_id == blurred_id {
2444            cx.handle().into_any()
2445        } else {
2446            let blurred_type = cx
2447                .views
2448                .get(&(cx.window_id, blurred_id))
2449                .unwrap()
2450                .as_any()
2451                .type_id();
2452            AnyViewHandle::new(
2453                cx.window_id,
2454                blurred_id,
2455                blurred_type,
2456                cx.ref_counts.clone(),
2457            )
2458        };
2459        View::focus_out(self, blurred_view_handle, &mut cx);
2460    }
2461
2462    fn key_down(&mut self, event: &KeyDownEvent, cx: &mut WindowContext, view_id: usize) -> bool {
2463        let mut cx = ViewContext::mutable(cx, view_id);
2464        View::key_down(self, event, &mut cx)
2465    }
2466
2467    fn key_up(&mut self, event: &KeyUpEvent, cx: &mut WindowContext, view_id: usize) -> bool {
2468        let mut cx = ViewContext::mutable(cx, view_id);
2469        View::key_up(self, event, &mut cx)
2470    }
2471
2472    fn modifiers_changed(
2473        &mut self,
2474        event: &ModifiersChangedEvent,
2475        cx: &mut WindowContext,
2476        view_id: usize,
2477    ) -> bool {
2478        let mut cx = ViewContext::mutable(cx, view_id);
2479        View::modifiers_changed(self, event, &mut cx)
2480    }
2481
2482    fn keymap_context(&self, cx: &AppContext) -> KeymapContext {
2483        View::keymap_context(self, cx)
2484    }
2485
2486    fn debug_json(&self, cx: &WindowContext) -> serde_json::Value {
2487        View::debug_json(self, cx)
2488    }
2489
2490    fn text_for_range(&self, range: Range<usize>, cx: &WindowContext) -> Option<String> {
2491        View::text_for_range(self, range, cx)
2492    }
2493
2494    fn selected_text_range(&self, cx: &WindowContext) -> Option<Range<usize>> {
2495        View::selected_text_range(self, cx)
2496    }
2497
2498    fn marked_text_range(&self, cx: &WindowContext) -> Option<Range<usize>> {
2499        View::marked_text_range(self, cx)
2500    }
2501
2502    fn unmark_text(&mut self, cx: &mut WindowContext, view_id: usize) {
2503        let mut cx = ViewContext::mutable(cx, view_id);
2504        View::unmark_text(self, &mut cx)
2505    }
2506
2507    fn replace_text_in_range(
2508        &mut self,
2509        range: Option<Range<usize>>,
2510        text: &str,
2511        cx: &mut WindowContext,
2512        view_id: usize,
2513    ) {
2514        let mut cx = ViewContext::mutable(cx, view_id);
2515        View::replace_text_in_range(self, range, text, &mut cx)
2516    }
2517
2518    fn replace_and_mark_text_in_range(
2519        &mut self,
2520        range: Option<Range<usize>>,
2521        new_text: &str,
2522        new_selected_range: Option<Range<usize>>,
2523        cx: &mut WindowContext,
2524        view_id: usize,
2525    ) {
2526        let mut cx = ViewContext::mutable(cx, view_id);
2527        View::replace_and_mark_text_in_range(self, range, new_text, new_selected_range, &mut cx)
2528    }
2529}
2530
2531pub struct ModelContext<'a, T: ?Sized> {
2532    app: &'a mut AppContext,
2533    model_id: usize,
2534    model_type: PhantomData<T>,
2535    halt_stream: bool,
2536}
2537
2538impl<'a, T: Entity> ModelContext<'a, T> {
2539    fn new(app: &'a mut AppContext, model_id: usize) -> Self {
2540        Self {
2541            app,
2542            model_id,
2543            model_type: PhantomData,
2544            halt_stream: false,
2545        }
2546    }
2547
2548    pub fn background(&self) -> &Arc<executor::Background> {
2549        &self.app.background
2550    }
2551
2552    pub fn halt_stream(&mut self) {
2553        self.halt_stream = true;
2554    }
2555
2556    pub fn model_id(&self) -> usize {
2557        self.model_id
2558    }
2559
2560    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
2561    where
2562        S: Entity,
2563        F: FnOnce(&mut ModelContext<S>) -> S,
2564    {
2565        self.app.add_model(build_model)
2566    }
2567
2568    pub fn emit(&mut self, payload: T::Event) {
2569        self.app.pending_effects.push_back(Effect::Event {
2570            entity_id: self.model_id,
2571            payload: Box::new(payload),
2572        });
2573    }
2574
2575    pub fn notify(&mut self) {
2576        self.app.notify_model(self.model_id);
2577    }
2578
2579    pub fn subscribe<S: Entity, F>(
2580        &mut self,
2581        handle: &ModelHandle<S>,
2582        mut callback: F,
2583    ) -> Subscription
2584    where
2585        S::Event: 'static,
2586        F: 'static + FnMut(&mut T, ModelHandle<S>, &S::Event, &mut ModelContext<T>),
2587    {
2588        let subscriber = self.weak_handle();
2589        self.app
2590            .subscribe_internal(handle, move |emitter, event, cx| {
2591                if let Some(subscriber) = subscriber.upgrade(cx) {
2592                    subscriber.update(cx, |subscriber, cx| {
2593                        callback(subscriber, emitter, event, cx);
2594                    });
2595                    true
2596                } else {
2597                    false
2598                }
2599            })
2600    }
2601
2602    pub fn observe<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F) -> Subscription
2603    where
2604        S: Entity,
2605        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ModelContext<T>),
2606    {
2607        let observer = self.weak_handle();
2608        self.app.observe_internal(handle, move |observed, cx| {
2609            if let Some(observer) = observer.upgrade(cx) {
2610                observer.update(cx, |observer, cx| {
2611                    callback(observer, observed, cx);
2612                });
2613                true
2614            } else {
2615                false
2616            }
2617        })
2618    }
2619
2620    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
2621    where
2622        G: Any,
2623        F: 'static + FnMut(&mut T, &mut ModelContext<T>),
2624    {
2625        let observer = self.weak_handle();
2626        self.app.observe_global::<G, _>(move |cx| {
2627            if let Some(observer) = observer.upgrade(cx) {
2628                observer.update(cx, |observer, cx| callback(observer, cx));
2629            }
2630        })
2631    }
2632
2633    pub fn observe_release<S, F>(
2634        &mut self,
2635        handle: &ModelHandle<S>,
2636        mut callback: F,
2637    ) -> Subscription
2638    where
2639        S: Entity,
2640        F: 'static + FnMut(&mut T, &S, &mut ModelContext<T>),
2641    {
2642        let observer = self.weak_handle();
2643        self.app.observe_release(handle, move |released, cx| {
2644            if let Some(observer) = observer.upgrade(cx) {
2645                observer.update(cx, |observer, cx| {
2646                    callback(observer, released, cx);
2647                });
2648            }
2649        })
2650    }
2651
2652    pub fn handle(&self) -> ModelHandle<T> {
2653        ModelHandle::new(self.model_id, &self.app.ref_counts)
2654    }
2655
2656    pub fn weak_handle(&self) -> WeakModelHandle<T> {
2657        WeakModelHandle::new(self.model_id)
2658    }
2659
2660    pub fn spawn<F, Fut, S>(&mut self, f: F) -> Task<S>
2661    where
2662        F: FnOnce(ModelHandle<T>, AsyncAppContext) -> Fut,
2663        Fut: 'static + Future<Output = S>,
2664        S: 'static,
2665    {
2666        let handle = self.handle();
2667        self.app.spawn(|cx| f(handle, cx))
2668    }
2669
2670    pub fn spawn_weak<F, Fut, S>(&mut self, f: F) -> Task<S>
2671    where
2672        F: FnOnce(WeakModelHandle<T>, AsyncAppContext) -> Fut,
2673        Fut: 'static + Future<Output = S>,
2674        S: 'static,
2675    {
2676        let handle = self.weak_handle();
2677        self.app.spawn(|cx| f(handle, cx))
2678    }
2679}
2680
2681impl<M> AsRef<AppContext> for ModelContext<'_, M> {
2682    fn as_ref(&self) -> &AppContext {
2683        &self.app
2684    }
2685}
2686
2687impl<M> AsMut<AppContext> for ModelContext<'_, M> {
2688    fn as_mut(&mut self) -> &mut AppContext {
2689        self.app
2690    }
2691}
2692
2693impl<M> BorrowAppContext for ModelContext<'_, M> {
2694    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
2695        self.app.read_with(f)
2696    }
2697
2698    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
2699        self.app.update(f)
2700    }
2701}
2702
2703impl<M> Deref for ModelContext<'_, M> {
2704    type Target = AppContext;
2705
2706    fn deref(&self) -> &Self::Target {
2707        self.app
2708    }
2709}
2710
2711impl<M> DerefMut for ModelContext<'_, M> {
2712    fn deref_mut(&mut self) -> &mut Self::Target {
2713        &mut self.app
2714    }
2715}
2716
2717pub struct ViewContext<'a, 'b, T: ?Sized> {
2718    window_context: Reference<'b, WindowContext<'a>>,
2719    view_id: usize,
2720    view_type: PhantomData<T>,
2721}
2722
2723impl<'a, 'b, T: View> Deref for ViewContext<'a, 'b, T> {
2724    type Target = WindowContext<'a>;
2725
2726    fn deref(&self) -> &Self::Target {
2727        &self.window_context
2728    }
2729}
2730
2731impl<T: View> DerefMut for ViewContext<'_, '_, T> {
2732    fn deref_mut(&mut self) -> &mut Self::Target {
2733        &mut self.window_context
2734    }
2735}
2736
2737impl<'a, 'b, V: View> ViewContext<'a, 'b, V> {
2738    pub(crate) fn mutable(window_context: &'b mut WindowContext<'a>, view_id: usize) -> Self {
2739        Self {
2740            window_context: Reference::Mutable(window_context),
2741            view_id,
2742            view_type: PhantomData,
2743        }
2744    }
2745
2746    pub(crate) fn immutable(window_context: &'b WindowContext<'a>, view_id: usize) -> Self {
2747        Self {
2748            window_context: Reference::Immutable(window_context),
2749            view_id,
2750            view_type: PhantomData,
2751        }
2752    }
2753
2754    pub fn window_context(&mut self) -> &mut WindowContext<'a> {
2755        &mut self.window_context
2756    }
2757
2758    pub fn handle(&self) -> ViewHandle<V> {
2759        ViewHandle::new(
2760            self.window_id,
2761            self.view_id,
2762            &self.window_context.ref_counts,
2763        )
2764    }
2765
2766    pub fn weak_handle(&self) -> WeakViewHandle<V> {
2767        WeakViewHandle::new(self.window_id, self.view_id)
2768    }
2769
2770    pub fn window_id(&self) -> usize {
2771        self.window_id
2772    }
2773
2774    pub fn view_id(&self) -> usize {
2775        self.view_id
2776    }
2777
2778    pub fn foreground(&self) -> &Rc<executor::Foreground> {
2779        self.window_context.foreground()
2780    }
2781
2782    pub fn background_executor(&self) -> &Arc<executor::Background> {
2783        &self.window_context.background
2784    }
2785
2786    pub fn platform(&self) -> &Arc<dyn Platform> {
2787        self.window_context.platform()
2788    }
2789
2790    pub fn prompt_for_paths(
2791        &self,
2792        options: PathPromptOptions,
2793    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
2794        self.window_context.prompt_for_paths(options)
2795    }
2796
2797    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
2798        self.window_context.prompt_for_new_path(directory)
2799    }
2800
2801    pub fn reveal_path(&self, path: &Path) {
2802        self.window_context.reveal_path(path)
2803    }
2804
2805    pub fn focus(&mut self, handle: &AnyViewHandle) {
2806        self.window_context
2807            .focus(handle.window_id, Some(handle.view_id));
2808    }
2809
2810    pub fn focus_self(&mut self) {
2811        let window_id = self.window_id;
2812        let view_id = self.view_id;
2813        self.window_context.focus(window_id, Some(view_id));
2814    }
2815
2816    pub fn is_self_focused(&self) -> bool {
2817        self.window.focused_view_id == Some(self.view_id)
2818    }
2819
2820    pub fn is_parent_view_focused(&self) -> bool {
2821        if let Some(parent_view_id) = self.ancestors(self.view_id).next().clone() {
2822            self.focused_view_id() == Some(parent_view_id)
2823        } else {
2824            false
2825        }
2826    }
2827
2828    pub fn focus_parent_view(&mut self) {
2829        let next = self.ancestors(self.view_id).next().clone();
2830        if let Some(parent_view_id) = next {
2831            let window_id = self.window_id;
2832            self.window_context.focus(window_id, Some(parent_view_id));
2833        }
2834    }
2835
2836    pub fn is_child(&self, view: impl Into<AnyViewHandle>) -> bool {
2837        let view = view.into();
2838        if self.window_id != view.window_id {
2839            return false;
2840        }
2841        self.ancestors(view.view_id)
2842            .skip(1) // Skip self id
2843            .any(|parent| parent == self.view_id)
2844    }
2845
2846    pub fn blur(&mut self) {
2847        let window_id = self.window_id;
2848        self.window_context.focus(window_id, None);
2849    }
2850
2851    pub fn on_window_should_close<F>(&mut self, mut callback: F)
2852    where
2853        F: 'static + FnMut(&mut V, &mut ViewContext<V>) -> bool,
2854    {
2855        let window_id = self.window_id;
2856        let view = self.weak_handle();
2857        self.pending_effects
2858            .push_back(Effect::WindowShouldCloseSubscription {
2859                window_id,
2860                callback: Box::new(move |cx| {
2861                    cx.update_window(window_id, |cx| {
2862                        if let Some(view) = view.upgrade(cx) {
2863                            view.update(cx, |view, cx| callback(view, cx))
2864                        } else {
2865                            true
2866                        }
2867                    })
2868                    .unwrap_or(true)
2869                }),
2870            });
2871    }
2872
2873    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
2874    where
2875        E: Entity,
2876        E::Event: 'static,
2877        H: Handle<E>,
2878        F: 'static + FnMut(&mut V, H, &E::Event, &mut ViewContext<V>),
2879    {
2880        let subscriber = self.weak_handle();
2881        self.window_context
2882            .subscribe_internal(handle, move |emitter, event, cx| {
2883                if let Some(subscriber) = subscriber.upgrade(cx) {
2884                    subscriber.update(cx, |subscriber, cx| {
2885                        callback(subscriber, emitter, event, cx);
2886                    });
2887                    true
2888                } else {
2889                    false
2890                }
2891            })
2892    }
2893
2894    pub fn observe<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
2895    where
2896        E: Entity,
2897        H: Handle<E>,
2898        F: 'static + FnMut(&mut V, H, &mut ViewContext<V>),
2899    {
2900        let window_id = self.window_id;
2901        let observer = self.weak_handle();
2902        self.window_context
2903            .observe_internal(handle, move |observed, cx| {
2904                cx.update_window(window_id, |cx| {
2905                    if let Some(observer) = observer.upgrade(cx) {
2906                        observer.update(cx, |observer, cx| {
2907                            callback(observer, observed, cx);
2908                        });
2909                        true
2910                    } else {
2911                        false
2912                    }
2913                })
2914                .unwrap_or(false)
2915            })
2916    }
2917
2918    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
2919    where
2920        G: Any,
2921        F: 'static + FnMut(&mut V, &mut ViewContext<V>),
2922    {
2923        let window_id = self.window_id;
2924        let observer = self.weak_handle();
2925        self.window_context.observe_global::<G, _>(move |cx| {
2926            cx.update_window(window_id, |cx| {
2927                if let Some(observer) = observer.upgrade(cx) {
2928                    observer.update(cx, |observer, cx| callback(observer, cx));
2929                }
2930            });
2931        })
2932    }
2933
2934    pub fn observe_focus<F, W>(&mut self, handle: &ViewHandle<W>, mut callback: F) -> Subscription
2935    where
2936        F: 'static + FnMut(&mut V, ViewHandle<W>, bool, &mut ViewContext<V>),
2937        W: View,
2938    {
2939        let observer = self.weak_handle();
2940        self.window_context
2941            .observe_focus(handle, move |observed, focused, cx| {
2942                if let Some(observer) = observer.upgrade(cx) {
2943                    observer.update(cx, |observer, cx| {
2944                        callback(observer, observed, focused, cx);
2945                    });
2946                    true
2947                } else {
2948                    false
2949                }
2950            })
2951    }
2952
2953    pub fn observe_release<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
2954    where
2955        E: Entity,
2956        H: Handle<E>,
2957        F: 'static + FnMut(&mut V, &E, &mut ViewContext<V>),
2958    {
2959        let window_id = self.window_id;
2960        let observer = self.weak_handle();
2961        self.window_context
2962            .observe_release(handle, move |released, cx| {
2963                cx.update_window(window_id, |cx| {
2964                    if let Some(observer) = observer.upgrade(cx) {
2965                        observer.update(cx, |observer, cx| {
2966                            callback(observer, released, cx);
2967                        });
2968                    }
2969                });
2970            })
2971    }
2972
2973    pub fn observe_actions<F>(&mut self, mut callback: F) -> Subscription
2974    where
2975        F: 'static + FnMut(&mut V, TypeId, &mut ViewContext<V>),
2976    {
2977        let window_id = self.window_id;
2978        let observer = self.weak_handle();
2979        self.window_context.observe_actions(move |action_id, cx| {
2980            cx.update_window(window_id, |cx| {
2981                if let Some(observer) = observer.upgrade(cx) {
2982                    observer.update(cx, |observer, cx| {
2983                        callback(observer, action_id, cx);
2984                    });
2985                }
2986            });
2987        })
2988    }
2989
2990    pub fn observe_window_activation<F>(&mut self, mut callback: F) -> Subscription
2991    where
2992        F: 'static + FnMut(&mut V, bool, &mut ViewContext<V>),
2993    {
2994        let observer = self.weak_handle();
2995        self.window_context
2996            .observe_window_activation(move |active, cx| {
2997                if let Some(observer) = observer.upgrade(cx) {
2998                    observer.update(cx, |observer, cx| {
2999                        callback(observer, active, cx);
3000                    });
3001                    true
3002                } else {
3003                    false
3004                }
3005            })
3006    }
3007
3008    pub fn observe_fullscreen<F>(&mut self, mut callback: F) -> Subscription
3009    where
3010        F: 'static + FnMut(&mut V, bool, &mut ViewContext<V>),
3011    {
3012        let observer = self.weak_handle();
3013        self.window_context.observe_fullscreen(move |active, cx| {
3014            if let Some(observer) = observer.upgrade(cx) {
3015                observer.update(cx, |observer, cx| {
3016                    callback(observer, active, cx);
3017                });
3018                true
3019            } else {
3020                false
3021            }
3022        })
3023    }
3024
3025    pub fn observe_keystrokes<F>(&mut self, mut callback: F) -> Subscription
3026    where
3027        F: 'static
3028            + FnMut(
3029                &mut V,
3030                &Keystroke,
3031                Option<&Box<dyn Action>>,
3032                &MatchResult,
3033                &mut ViewContext<V>,
3034            ) -> bool,
3035    {
3036        let observer = self.weak_handle();
3037        self.window_context
3038            .observe_keystrokes(move |keystroke, result, handled_by, cx| {
3039                if let Some(observer) = observer.upgrade(cx) {
3040                    observer.update(cx, |observer, cx| {
3041                        callback(observer, keystroke, handled_by, result, cx);
3042                    });
3043                    true
3044                } else {
3045                    false
3046                }
3047            })
3048    }
3049
3050    pub fn observe_window_bounds<F>(&mut self, mut callback: F) -> Subscription
3051    where
3052        F: 'static + FnMut(&mut V, WindowBounds, Uuid, &mut ViewContext<V>),
3053    {
3054        let observer = self.weak_handle();
3055        self.window_context
3056            .observe_window_bounds(move |bounds, display, cx| {
3057                if let Some(observer) = observer.upgrade(cx) {
3058                    observer.update(cx, |observer, cx| {
3059                        callback(observer, bounds, display, cx);
3060                    });
3061                    true
3062                } else {
3063                    false
3064                }
3065            })
3066    }
3067
3068    pub fn observe_active_labeled_tasks<F>(&mut self, mut callback: F) -> Subscription
3069    where
3070        F: 'static + FnMut(&mut V, &mut ViewContext<V>),
3071    {
3072        let window_id = self.window_id;
3073        let observer = self.weak_handle();
3074        self.window_context.observe_active_labeled_tasks(move |cx| {
3075            cx.update_window(window_id, |cx| {
3076                if let Some(observer) = observer.upgrade(cx) {
3077                    observer.update(cx, |observer, cx| {
3078                        callback(observer, cx);
3079                    });
3080                    true
3081                } else {
3082                    false
3083                }
3084            })
3085            .unwrap_or(false)
3086        })
3087    }
3088
3089    pub fn emit(&mut self, payload: V::Event) {
3090        self.window_context
3091            .pending_effects
3092            .push_back(Effect::Event {
3093                entity_id: self.view_id,
3094                payload: Box::new(payload),
3095            });
3096    }
3097
3098    pub fn notify(&mut self) {
3099        let window_id = self.window_id;
3100        let view_id = self.view_id;
3101        self.window_context.notify_view(window_id, view_id);
3102    }
3103
3104    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut V, &mut ViewContext<V>)) {
3105        let handle = self.handle();
3106        self.window_context
3107            .defer(move |cx| handle.update(cx, |view, cx| callback(view, cx)))
3108    }
3109
3110    pub fn after_window_update(
3111        &mut self,
3112        callback: impl 'static + FnOnce(&mut V, &mut ViewContext<V>),
3113    ) {
3114        let window_id = self.window_id;
3115        let handle = self.handle();
3116        self.window_context.after_window_update(move |cx| {
3117            cx.update_window(window_id, |cx| {
3118                handle.update(cx, |view, cx| {
3119                    callback(view, cx);
3120                })
3121            });
3122        })
3123    }
3124
3125    pub fn propagate_action(&mut self) {
3126        self.window_context.halt_action_dispatch = false;
3127    }
3128
3129    pub fn spawn_labeled<F, Fut, S>(&mut self, task_label: &'static str, f: F) -> Task<S>
3130    where
3131        F: FnOnce(WeakViewHandle<V>, AsyncAppContext) -> Fut,
3132        Fut: 'static + Future<Output = S>,
3133        S: 'static,
3134    {
3135        let handle = self.weak_handle();
3136        self.window_context
3137            .spawn_labeled(task_label, |cx| f(handle, cx))
3138    }
3139
3140    pub fn spawn<F, Fut, S>(&mut self, f: F) -> Task<S>
3141    where
3142        F: FnOnce(WeakViewHandle<V>, AsyncAppContext) -> Fut,
3143        Fut: 'static + Future<Output = S>,
3144        S: 'static,
3145    {
3146        let handle = self.weak_handle();
3147        self.window_context.spawn(|cx| f(handle, cx))
3148    }
3149
3150    pub fn mouse_state<Tag: 'static>(&self, region_id: usize) -> MouseState {
3151        let region_id = MouseRegionId::new::<Tag>(self.view_id, region_id);
3152        MouseState {
3153            hovered: self.window.hovered_region_ids.contains(&region_id),
3154            clicked: self
3155                .window
3156                .clicked_region_ids
3157                .get(&region_id)
3158                .and_then(|_| self.window.clicked_button),
3159            accessed_hovered: false,
3160            accessed_clicked: false,
3161        }
3162    }
3163
3164    pub fn element_state<Tag: 'static, T: 'static>(
3165        &mut self,
3166        element_id: usize,
3167        initial: T,
3168    ) -> ElementStateHandle<T> {
3169        let id = ElementStateId {
3170            view_id: self.view_id(),
3171            element_id,
3172            tag: TypeId::of::<Tag>(),
3173        };
3174        self.element_states
3175            .entry(id)
3176            .or_insert_with(|| Box::new(initial));
3177        ElementStateHandle::new(id, self.frame_count, &self.ref_counts)
3178    }
3179
3180    pub fn default_element_state<Tag: 'static, T: 'static + Default>(
3181        &mut self,
3182        element_id: usize,
3183    ) -> ElementStateHandle<T> {
3184        self.element_state::<Tag, T>(element_id, T::default())
3185    }
3186}
3187
3188impl<V> BorrowAppContext for ViewContext<'_, '_, V> {
3189    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
3190        BorrowAppContext::read_with(&*self.window_context, f)
3191    }
3192
3193    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
3194        BorrowAppContext::update(&mut *self.window_context, f)
3195    }
3196}
3197
3198impl<V> BorrowWindowContext for ViewContext<'_, '_, V> {
3199    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T {
3200        BorrowWindowContext::read_with(&*self.window_context, window_id, f)
3201    }
3202
3203    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T {
3204        BorrowWindowContext::update(&mut *self.window_context, window_id, f)
3205    }
3206}
3207
3208pub struct LayoutContext<'a, 'b, 'c, V: View> {
3209    view_context: &'c mut ViewContext<'a, 'b, V>,
3210    new_parents: &'c mut HashMap<usize, usize>,
3211    views_to_notify_if_ancestors_change: &'c mut HashSet<usize>,
3212    pub refreshing: bool,
3213}
3214
3215impl<'a, 'b, 'c, V: View> LayoutContext<'a, 'b, 'c, V> {
3216    pub fn new(
3217        view_context: &'c mut ViewContext<'a, 'b, V>,
3218        new_parents: &'c mut HashMap<usize, usize>,
3219        views_to_notify_if_ancestors_change: &'c mut HashSet<usize>,
3220        refreshing: bool,
3221    ) -> Self {
3222        Self {
3223            view_context,
3224            new_parents,
3225            views_to_notify_if_ancestors_change,
3226            refreshing,
3227        }
3228    }
3229
3230    pub fn view_context(&mut self) -> &mut ViewContext<'a, 'b, V> {
3231        self.view_context
3232    }
3233}
3234
3235impl<'a, 'b, 'c, V: View> Deref for LayoutContext<'a, 'b, 'c, V> {
3236    type Target = ViewContext<'a, 'b, V>;
3237
3238    fn deref(&self) -> &Self::Target {
3239        &self.view_context
3240    }
3241}
3242
3243impl<V: View> DerefMut for LayoutContext<'_, '_, '_, V> {
3244    fn deref_mut(&mut self) -> &mut Self::Target {
3245        &mut self.view_context
3246    }
3247}
3248
3249impl<V: View> BorrowAppContext for LayoutContext<'_, '_, '_, V> {
3250    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
3251        BorrowAppContext::read_with(&*self.view_context, f)
3252    }
3253
3254    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
3255        BorrowAppContext::update(&mut *self.view_context, f)
3256    }
3257}
3258
3259impl<V: View> BorrowWindowContext for LayoutContext<'_, '_, '_, V> {
3260    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T {
3261        BorrowWindowContext::read_with(&*self.view_context, window_id, f)
3262    }
3263
3264    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T {
3265        BorrowWindowContext::update(&mut *self.view_context, window_id, f)
3266    }
3267}
3268
3269pub struct EventContext<'a, 'b, 'c, V: View> {
3270    view_context: &'c mut ViewContext<'a, 'b, V>,
3271    pub(crate) handled: bool,
3272}
3273
3274impl<'a, 'b, 'c, V: View> EventContext<'a, 'b, 'c, V> {
3275    pub(crate) fn new(view_context: &'c mut ViewContext<'a, 'b, V>) -> Self {
3276        EventContext {
3277            view_context,
3278            handled: true,
3279        }
3280    }
3281
3282    pub fn propagate_event(&mut self) {
3283        self.handled = false;
3284    }
3285}
3286
3287impl<'a, 'b, 'c, V: View> Deref for EventContext<'a, 'b, 'c, V> {
3288    type Target = ViewContext<'a, 'b, V>;
3289
3290    fn deref(&self) -> &Self::Target {
3291        &self.view_context
3292    }
3293}
3294
3295impl<V: View> DerefMut for EventContext<'_, '_, '_, V> {
3296    fn deref_mut(&mut self) -> &mut Self::Target {
3297        &mut self.view_context
3298    }
3299}
3300
3301impl<V: View> BorrowAppContext for EventContext<'_, '_, '_, V> {
3302    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
3303        BorrowAppContext::read_with(&*self.view_context, f)
3304    }
3305
3306    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
3307        BorrowAppContext::update(&mut *self.view_context, f)
3308    }
3309}
3310
3311impl<V: View> BorrowWindowContext for EventContext<'_, '_, '_, V> {
3312    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T {
3313        BorrowWindowContext::read_with(&*self.view_context, window_id, f)
3314    }
3315
3316    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T {
3317        BorrowWindowContext::update(&mut *self.view_context, window_id, f)
3318    }
3319}
3320
3321pub(crate) enum Reference<'a, T> {
3322    Immutable(&'a T),
3323    Mutable(&'a mut T),
3324}
3325
3326impl<'a, T> Deref for Reference<'a, T> {
3327    type Target = T;
3328
3329    fn deref(&self) -> &Self::Target {
3330        match self {
3331            Reference::Immutable(target) => target,
3332            Reference::Mutable(target) => target,
3333        }
3334    }
3335}
3336
3337impl<'a, T> DerefMut for Reference<'a, T> {
3338    fn deref_mut(&mut self) -> &mut Self::Target {
3339        match self {
3340            Reference::Immutable(_) => {
3341                panic!("cannot mutably deref an immutable reference. this is a bug in GPUI.");
3342            }
3343            Reference::Mutable(target) => target,
3344        }
3345    }
3346}
3347
3348#[derive(Debug, Clone, Default)]
3349pub struct MouseState {
3350    pub(crate) hovered: bool,
3351    pub(crate) clicked: Option<MouseButton>,
3352    pub(crate) accessed_hovered: bool,
3353    pub(crate) accessed_clicked: bool,
3354}
3355
3356impl MouseState {
3357    pub fn hovered(&mut self) -> bool {
3358        self.accessed_hovered = true;
3359        self.hovered
3360    }
3361
3362    pub fn clicked(&mut self) -> Option<MouseButton> {
3363        self.accessed_clicked = true;
3364        self.clicked
3365    }
3366
3367    pub fn accessed_hovered(&self) -> bool {
3368        self.accessed_hovered
3369    }
3370
3371    pub fn accessed_clicked(&self) -> bool {
3372        self.accessed_clicked
3373    }
3374}
3375
3376pub trait Handle<T> {
3377    type Weak: 'static;
3378    fn id(&self) -> usize;
3379    fn location(&self) -> EntityLocation;
3380    fn downgrade(&self) -> Self::Weak;
3381    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
3382    where
3383        Self: Sized;
3384}
3385
3386pub trait WeakHandle {
3387    fn id(&self) -> usize;
3388}
3389
3390#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
3391pub enum EntityLocation {
3392    Model(usize),
3393    View(usize, usize),
3394}
3395
3396pub struct ModelHandle<T: Entity> {
3397    any_handle: AnyModelHandle,
3398    model_type: PhantomData<T>,
3399}
3400
3401impl<T: Entity> Deref for ModelHandle<T> {
3402    type Target = AnyModelHandle;
3403
3404    fn deref(&self) -> &Self::Target {
3405        &self.any_handle
3406    }
3407}
3408
3409impl<T: Entity> ModelHandle<T> {
3410    fn new(model_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
3411        Self {
3412            any_handle: AnyModelHandle::new(model_id, TypeId::of::<T>(), ref_counts.clone()),
3413            model_type: PhantomData,
3414        }
3415    }
3416
3417    pub fn downgrade(&self) -> WeakModelHandle<T> {
3418        WeakModelHandle::new(self.model_id)
3419    }
3420
3421    pub fn id(&self) -> usize {
3422        self.model_id
3423    }
3424
3425    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
3426        cx.read_model(self)
3427    }
3428
3429    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
3430    where
3431        C: BorrowAppContext,
3432        F: FnOnce(&T, &AppContext) -> S,
3433    {
3434        cx.read_with(|cx| read(self.read(cx), cx))
3435    }
3436
3437    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
3438    where
3439        C: BorrowAppContext,
3440        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
3441    {
3442        let mut update = Some(update);
3443        cx.update(|cx| {
3444            cx.update_model(self, &mut |model, cx| {
3445                let update = update.take().unwrap();
3446                update(model, cx)
3447            })
3448        })
3449    }
3450}
3451
3452impl<T: Entity> Clone for ModelHandle<T> {
3453    fn clone(&self) -> Self {
3454        Self::new(self.model_id, &self.ref_counts)
3455    }
3456}
3457
3458impl<T: Entity> PartialEq for ModelHandle<T> {
3459    fn eq(&self, other: &Self) -> bool {
3460        self.model_id == other.model_id
3461    }
3462}
3463
3464impl<T: Entity> Eq for ModelHandle<T> {}
3465
3466impl<T: Entity> PartialEq<WeakModelHandle<T>> for ModelHandle<T> {
3467    fn eq(&self, other: &WeakModelHandle<T>) -> bool {
3468        self.model_id == other.model_id
3469    }
3470}
3471
3472impl<T: Entity> Hash for ModelHandle<T> {
3473    fn hash<H: Hasher>(&self, state: &mut H) {
3474        self.model_id.hash(state);
3475    }
3476}
3477
3478impl<T: Entity> std::borrow::Borrow<usize> for ModelHandle<T> {
3479    fn borrow(&self) -> &usize {
3480        &self.model_id
3481    }
3482}
3483
3484impl<T: Entity> Debug for ModelHandle<T> {
3485    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3486        f.debug_tuple(&format!("ModelHandle<{}>", type_name::<T>()))
3487            .field(&self.model_id)
3488            .finish()
3489    }
3490}
3491
3492unsafe impl<T: Entity> Send for ModelHandle<T> {}
3493unsafe impl<T: Entity> Sync for ModelHandle<T> {}
3494
3495impl<T: Entity> Handle<T> for ModelHandle<T> {
3496    type Weak = WeakModelHandle<T>;
3497
3498    fn id(&self) -> usize {
3499        self.model_id
3500    }
3501
3502    fn location(&self) -> EntityLocation {
3503        EntityLocation::Model(self.model_id)
3504    }
3505
3506    fn downgrade(&self) -> Self::Weak {
3507        self.downgrade()
3508    }
3509
3510    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
3511    where
3512        Self: Sized,
3513    {
3514        weak.upgrade(cx)
3515    }
3516}
3517
3518pub struct WeakModelHandle<T> {
3519    any_handle: AnyWeakModelHandle,
3520    model_type: PhantomData<T>,
3521}
3522
3523impl<T> WeakModelHandle<T> {
3524    pub fn into_any(self) -> AnyWeakModelHandle {
3525        self.any_handle
3526    }
3527}
3528
3529impl<T> Deref for WeakModelHandle<T> {
3530    type Target = AnyWeakModelHandle;
3531
3532    fn deref(&self) -> &Self::Target {
3533        &self.any_handle
3534    }
3535}
3536
3537impl<T> WeakHandle for WeakModelHandle<T> {
3538    fn id(&self) -> usize {
3539        self.model_id
3540    }
3541}
3542
3543unsafe impl<T> Send for WeakModelHandle<T> {}
3544unsafe impl<T> Sync for WeakModelHandle<T> {}
3545
3546impl<T: Entity> WeakModelHandle<T> {
3547    fn new(model_id: usize) -> Self {
3548        Self {
3549            any_handle: AnyWeakModelHandle {
3550                model_id,
3551                model_type: TypeId::of::<T>(),
3552            },
3553            model_type: PhantomData,
3554        }
3555    }
3556
3557    pub fn id(&self) -> usize {
3558        self.model_id
3559    }
3560
3561    pub fn is_upgradable(&self, cx: &impl BorrowAppContext) -> bool {
3562        cx.read_with(|cx| cx.model_handle_is_upgradable(self))
3563    }
3564
3565    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<ModelHandle<T>> {
3566        cx.read_with(|cx| cx.upgrade_model_handle(self))
3567    }
3568}
3569
3570impl<T> Hash for WeakModelHandle<T> {
3571    fn hash<H: Hasher>(&self, state: &mut H) {
3572        self.model_id.hash(state)
3573    }
3574}
3575
3576impl<T> PartialEq for WeakModelHandle<T> {
3577    fn eq(&self, other: &Self) -> bool {
3578        self.model_id == other.model_id
3579    }
3580}
3581
3582impl<T> Eq for WeakModelHandle<T> {}
3583
3584impl<T: Entity> PartialEq<ModelHandle<T>> for WeakModelHandle<T> {
3585    fn eq(&self, other: &ModelHandle<T>) -> bool {
3586        self.model_id == other.model_id
3587    }
3588}
3589
3590impl<T> Clone for WeakModelHandle<T> {
3591    fn clone(&self) -> Self {
3592        Self {
3593            any_handle: self.any_handle.clone(),
3594            model_type: PhantomData,
3595        }
3596    }
3597}
3598
3599impl<T> Copy for WeakModelHandle<T> {}
3600
3601#[repr(transparent)]
3602pub struct ViewHandle<T> {
3603    any_handle: AnyViewHandle,
3604    view_type: PhantomData<T>,
3605}
3606
3607impl<T> Deref for ViewHandle<T> {
3608    type Target = AnyViewHandle;
3609
3610    fn deref(&self) -> &Self::Target {
3611        &self.any_handle
3612    }
3613}
3614
3615impl<T: View> ViewHandle<T> {
3616    fn new(window_id: usize, view_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
3617        Self {
3618            any_handle: AnyViewHandle::new(
3619                window_id,
3620                view_id,
3621                TypeId::of::<T>(),
3622                ref_counts.clone(),
3623            ),
3624            view_type: PhantomData,
3625        }
3626    }
3627
3628    pub fn downgrade(&self) -> WeakViewHandle<T> {
3629        WeakViewHandle::new(self.window_id, self.view_id)
3630    }
3631
3632    pub fn into_any(self) -> AnyViewHandle {
3633        self.any_handle
3634    }
3635
3636    pub fn window_id(&self) -> usize {
3637        self.window_id
3638    }
3639
3640    pub fn id(&self) -> usize {
3641        self.view_id
3642    }
3643
3644    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
3645        cx.read_view(self)
3646    }
3647
3648    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
3649    where
3650        C: BorrowWindowContext,
3651        F: FnOnce(&T, &ViewContext<T>) -> S,
3652    {
3653        cx.read_with(self.window_id, |cx| {
3654            let cx = ViewContext::immutable(cx, self.view_id);
3655            read(cx.read_view(self), &cx)
3656        })
3657    }
3658
3659    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
3660    where
3661        C: BorrowWindowContext,
3662        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
3663    {
3664        let mut update = Some(update);
3665
3666        cx.update(self.window_id, |cx| {
3667            cx.update_view(self, &mut |view, cx| {
3668                let update = update.take().unwrap();
3669                update(view, cx)
3670            })
3671        })
3672    }
3673
3674    pub fn is_focused(&self, cx: &WindowContext) -> bool {
3675        cx.focused_view_id() == Some(self.view_id)
3676    }
3677}
3678
3679impl<T: View> Clone for ViewHandle<T> {
3680    fn clone(&self) -> Self {
3681        ViewHandle::new(self.window_id, self.view_id, &self.ref_counts)
3682    }
3683}
3684
3685impl<T> PartialEq for ViewHandle<T> {
3686    fn eq(&self, other: &Self) -> bool {
3687        self.window_id == other.window_id && self.view_id == other.view_id
3688    }
3689}
3690
3691impl<T> PartialEq<WeakViewHandle<T>> for ViewHandle<T> {
3692    fn eq(&self, other: &WeakViewHandle<T>) -> bool {
3693        self.window_id == other.window_id && self.view_id == other.view_id
3694    }
3695}
3696
3697impl<T> PartialEq<ViewHandle<T>> for WeakViewHandle<T> {
3698    fn eq(&self, other: &ViewHandle<T>) -> bool {
3699        self.window_id == other.window_id && self.view_id == other.view_id
3700    }
3701}
3702
3703impl<T> Eq for ViewHandle<T> {}
3704
3705impl<T> Hash for ViewHandle<T> {
3706    fn hash<H: Hasher>(&self, state: &mut H) {
3707        self.window_id.hash(state);
3708        self.view_id.hash(state);
3709    }
3710}
3711
3712impl<T> Debug for ViewHandle<T> {
3713    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3714        f.debug_struct(&format!("ViewHandle<{}>", type_name::<T>()))
3715            .field("window_id", &self.window_id)
3716            .field("view_id", &self.view_id)
3717            .finish()
3718    }
3719}
3720
3721impl<T: View> Handle<T> for ViewHandle<T> {
3722    type Weak = WeakViewHandle<T>;
3723
3724    fn id(&self) -> usize {
3725        self.view_id
3726    }
3727
3728    fn location(&self) -> EntityLocation {
3729        EntityLocation::View(self.window_id, self.view_id)
3730    }
3731
3732    fn downgrade(&self) -> Self::Weak {
3733        self.downgrade()
3734    }
3735
3736    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
3737    where
3738        Self: Sized,
3739    {
3740        weak.upgrade(cx)
3741    }
3742}
3743
3744pub struct AnyViewHandle {
3745    window_id: usize,
3746    view_id: usize,
3747    view_type: TypeId,
3748    ref_counts: Arc<Mutex<RefCounts>>,
3749
3750    #[cfg(any(test, feature = "test-support"))]
3751    handle_id: usize,
3752}
3753
3754impl AnyViewHandle {
3755    fn new(
3756        window_id: usize,
3757        view_id: usize,
3758        view_type: TypeId,
3759        ref_counts: Arc<Mutex<RefCounts>>,
3760    ) -> Self {
3761        ref_counts.lock().inc_view(window_id, view_id);
3762
3763        #[cfg(any(test, feature = "test-support"))]
3764        let handle_id = ref_counts
3765            .lock()
3766            .leak_detector
3767            .lock()
3768            .handle_created(None, view_id);
3769
3770        Self {
3771            window_id,
3772            view_id,
3773            view_type,
3774            ref_counts,
3775            #[cfg(any(test, feature = "test-support"))]
3776            handle_id,
3777        }
3778    }
3779
3780    pub fn window_id(&self) -> usize {
3781        self.window_id
3782    }
3783
3784    pub fn id(&self) -> usize {
3785        self.view_id
3786    }
3787
3788    pub fn is<T: 'static>(&self) -> bool {
3789        TypeId::of::<T>() == self.view_type
3790    }
3791
3792    pub fn downcast<T: View>(self) -> Option<ViewHandle<T>> {
3793        if self.is::<T>() {
3794            Some(ViewHandle {
3795                any_handle: self,
3796                view_type: PhantomData,
3797            })
3798        } else {
3799            None
3800        }
3801    }
3802
3803    pub fn downcast_ref<T: View>(&self) -> Option<&ViewHandle<T>> {
3804        if self.is::<T>() {
3805            Some(unsafe { mem::transmute(self) })
3806        } else {
3807            None
3808        }
3809    }
3810
3811    pub fn downgrade(&self) -> AnyWeakViewHandle {
3812        AnyWeakViewHandle {
3813            window_id: self.window_id,
3814            view_id: self.view_id,
3815            view_type: self.view_type,
3816        }
3817    }
3818
3819    pub fn view_type(&self) -> TypeId {
3820        self.view_type
3821    }
3822
3823    pub fn debug_json<'a, 'b>(&self, cx: &'b WindowContext<'a>) -> serde_json::Value {
3824        cx.views
3825            .get(&(self.window_id, self.view_id))
3826            .map_or_else(|| serde_json::Value::Null, |view| view.debug_json(cx))
3827    }
3828}
3829
3830impl Clone for AnyViewHandle {
3831    fn clone(&self) -> Self {
3832        Self::new(
3833            self.window_id,
3834            self.view_id,
3835            self.view_type,
3836            self.ref_counts.clone(),
3837        )
3838    }
3839}
3840
3841impl<T> PartialEq<ViewHandle<T>> for AnyViewHandle {
3842    fn eq(&self, other: &ViewHandle<T>) -> bool {
3843        self.window_id == other.window_id && self.view_id == other.view_id
3844    }
3845}
3846
3847impl Drop for AnyViewHandle {
3848    fn drop(&mut self) {
3849        self.ref_counts
3850            .lock()
3851            .dec_view(self.window_id, self.view_id);
3852        #[cfg(any(test, feature = "test-support"))]
3853        self.ref_counts
3854            .lock()
3855            .leak_detector
3856            .lock()
3857            .handle_dropped(self.view_id, self.handle_id);
3858    }
3859}
3860
3861pub struct AnyModelHandle {
3862    model_id: usize,
3863    model_type: TypeId,
3864    ref_counts: Arc<Mutex<RefCounts>>,
3865
3866    #[cfg(any(test, feature = "test-support"))]
3867    handle_id: usize,
3868}
3869
3870impl AnyModelHandle {
3871    fn new(model_id: usize, model_type: TypeId, ref_counts: Arc<Mutex<RefCounts>>) -> Self {
3872        ref_counts.lock().inc_model(model_id);
3873
3874        #[cfg(any(test, feature = "test-support"))]
3875        let handle_id = ref_counts
3876            .lock()
3877            .leak_detector
3878            .lock()
3879            .handle_created(None, model_id);
3880
3881        Self {
3882            model_id,
3883            model_type,
3884            ref_counts,
3885
3886            #[cfg(any(test, feature = "test-support"))]
3887            handle_id,
3888        }
3889    }
3890
3891    pub fn downcast<T: Entity>(self) -> Option<ModelHandle<T>> {
3892        if self.is::<T>() {
3893            Some(ModelHandle {
3894                any_handle: self,
3895                model_type: PhantomData,
3896            })
3897        } else {
3898            None
3899        }
3900    }
3901
3902    pub fn downgrade(&self) -> AnyWeakModelHandle {
3903        AnyWeakModelHandle {
3904            model_id: self.model_id,
3905            model_type: self.model_type,
3906        }
3907    }
3908
3909    pub fn is<T: Entity>(&self) -> bool {
3910        self.model_type == TypeId::of::<T>()
3911    }
3912
3913    pub fn model_type(&self) -> TypeId {
3914        self.model_type
3915    }
3916}
3917
3918impl Clone for AnyModelHandle {
3919    fn clone(&self) -> Self {
3920        Self::new(self.model_id, self.model_type, self.ref_counts.clone())
3921    }
3922}
3923
3924impl Drop for AnyModelHandle {
3925    fn drop(&mut self) {
3926        let mut ref_counts = self.ref_counts.lock();
3927        ref_counts.dec_model(self.model_id);
3928
3929        #[cfg(any(test, feature = "test-support"))]
3930        ref_counts
3931            .leak_detector
3932            .lock()
3933            .handle_dropped(self.model_id, self.handle_id);
3934    }
3935}
3936
3937#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy)]
3938pub struct AnyWeakModelHandle {
3939    model_id: usize,
3940    model_type: TypeId,
3941}
3942
3943impl AnyWeakModelHandle {
3944    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<AnyModelHandle> {
3945        cx.read_with(|cx| cx.upgrade_any_model_handle(self))
3946    }
3947
3948    pub fn model_type(&self) -> TypeId {
3949        self.model_type
3950    }
3951
3952    fn is<T: 'static>(&self) -> bool {
3953        TypeId::of::<T>() == self.model_type
3954    }
3955
3956    pub fn downcast<T: Entity>(self) -> Option<WeakModelHandle<T>> {
3957        if self.is::<T>() {
3958            let result = Some(WeakModelHandle {
3959                any_handle: self,
3960                model_type: PhantomData,
3961            });
3962
3963            result
3964        } else {
3965            None
3966        }
3967    }
3968}
3969
3970#[derive(Debug, Copy)]
3971pub struct WeakViewHandle<T> {
3972    any_handle: AnyWeakViewHandle,
3973    view_type: PhantomData<T>,
3974}
3975
3976impl<T> WeakHandle for WeakViewHandle<T> {
3977    fn id(&self) -> usize {
3978        self.view_id
3979    }
3980}
3981
3982impl<V: View> WeakViewHandle<V> {
3983    fn new(window_id: usize, view_id: usize) -> Self {
3984        Self {
3985            any_handle: AnyWeakViewHandle {
3986                window_id,
3987                view_id,
3988                view_type: TypeId::of::<V>(),
3989            },
3990            view_type: PhantomData,
3991        }
3992    }
3993
3994    pub fn id(&self) -> usize {
3995        self.view_id
3996    }
3997
3998    pub fn window_id(&self) -> usize {
3999        self.window_id
4000    }
4001
4002    pub fn into_any(self) -> AnyWeakViewHandle {
4003        self.any_handle
4004    }
4005
4006    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<ViewHandle<V>> {
4007        cx.read_with(|cx| cx.upgrade_view_handle(self))
4008    }
4009
4010    pub fn read_with<T>(
4011        &self,
4012        cx: &AsyncAppContext,
4013        read: impl FnOnce(&V, &ViewContext<V>) -> T,
4014    ) -> Result<T> {
4015        cx.read(|cx| {
4016            let handle = cx
4017                .upgrade_view_handle(self)
4018                .ok_or_else(|| anyhow!("view {} was dropped", V::ui_name()))?;
4019            cx.read_window(self.window_id, |cx| handle.read_with(cx, read))
4020                .ok_or_else(|| anyhow!("window was removed"))
4021        })
4022    }
4023
4024    pub fn update<T>(
4025        &self,
4026        cx: &mut AsyncAppContext,
4027        update: impl FnOnce(&mut V, &mut ViewContext<V>) -> T,
4028    ) -> Result<T> {
4029        cx.update(|cx| {
4030            let handle = cx
4031                .upgrade_view_handle(self)
4032                .ok_or_else(|| anyhow!("view {} was dropped", V::ui_name()))?;
4033            cx.update_window(self.window_id, |cx| handle.update(cx, update))
4034                .ok_or_else(|| anyhow!("window was removed"))
4035        })
4036    }
4037}
4038
4039impl<T> Deref for WeakViewHandle<T> {
4040    type Target = AnyWeakViewHandle;
4041
4042    fn deref(&self) -> &Self::Target {
4043        &self.any_handle
4044    }
4045}
4046
4047impl<T> Clone for WeakViewHandle<T> {
4048    fn clone(&self) -> Self {
4049        Self {
4050            any_handle: self.any_handle.clone(),
4051            view_type: PhantomData,
4052        }
4053    }
4054}
4055
4056impl<T> PartialEq for WeakViewHandle<T> {
4057    fn eq(&self, other: &Self) -> bool {
4058        self.window_id == other.window_id && self.view_id == other.view_id
4059    }
4060}
4061
4062impl<T> Eq for WeakViewHandle<T> {}
4063
4064impl<T> Hash for WeakViewHandle<T> {
4065    fn hash<H: Hasher>(&self, state: &mut H) {
4066        self.any_handle.hash(state);
4067    }
4068}
4069
4070#[derive(Debug, Clone, Copy)]
4071pub struct AnyWeakViewHandle {
4072    window_id: usize,
4073    view_id: usize,
4074    view_type: TypeId,
4075}
4076
4077impl AnyWeakViewHandle {
4078    pub fn id(&self) -> usize {
4079        self.view_id
4080    }
4081
4082    fn is<T: 'static>(&self) -> bool {
4083        TypeId::of::<T>() == self.view_type
4084    }
4085
4086    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<AnyViewHandle> {
4087        cx.read_with(|cx| cx.upgrade_any_view_handle(self))
4088    }
4089
4090    pub fn downcast<T: View>(self) -> Option<WeakViewHandle<T>> {
4091        if self.is::<T>() {
4092            Some(WeakViewHandle {
4093                any_handle: self,
4094                view_type: PhantomData,
4095            })
4096        } else {
4097            None
4098        }
4099    }
4100}
4101
4102impl Hash for AnyWeakViewHandle {
4103    fn hash<H: Hasher>(&self, state: &mut H) {
4104        self.window_id.hash(state);
4105        self.view_id.hash(state);
4106        self.view_type.hash(state);
4107    }
4108}
4109
4110#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
4111pub struct ElementStateId {
4112    view_id: usize,
4113    element_id: usize,
4114    tag: TypeId,
4115}
4116
4117pub struct ElementStateHandle<T> {
4118    value_type: PhantomData<T>,
4119    id: ElementStateId,
4120    ref_counts: Weak<Mutex<RefCounts>>,
4121}
4122
4123impl<T: 'static> ElementStateHandle<T> {
4124    fn new(id: ElementStateId, frame_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
4125        ref_counts.lock().inc_element_state(id, frame_id);
4126        Self {
4127            value_type: PhantomData,
4128            id,
4129            ref_counts: Arc::downgrade(ref_counts),
4130        }
4131    }
4132
4133    pub fn id(&self) -> ElementStateId {
4134        self.id
4135    }
4136
4137    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
4138        cx.element_states
4139            .get(&self.id)
4140            .unwrap()
4141            .downcast_ref()
4142            .unwrap()
4143    }
4144
4145    pub fn update<C, D, R>(&self, cx: &mut C, f: impl FnOnce(&mut T, &mut C) -> R) -> R
4146    where
4147        C: DerefMut<Target = D>,
4148        D: DerefMut<Target = AppContext>,
4149    {
4150        let mut element_state = cx.deref_mut().element_states.remove(&self.id).unwrap();
4151        let result = f(element_state.downcast_mut().unwrap(), cx);
4152        cx.deref_mut().element_states.insert(self.id, element_state);
4153        result
4154    }
4155}
4156
4157impl<T> Drop for ElementStateHandle<T> {
4158    fn drop(&mut self) {
4159        if let Some(ref_counts) = self.ref_counts.upgrade() {
4160            ref_counts.lock().dec_element_state(self.id);
4161        }
4162    }
4163}
4164
4165#[must_use]
4166pub enum Subscription {
4167    Subscription(callback_collection::Subscription<usize, SubscriptionCallback>),
4168    Observation(callback_collection::Subscription<usize, ObservationCallback>),
4169    GlobalSubscription(callback_collection::Subscription<TypeId, GlobalSubscriptionCallback>),
4170    GlobalObservation(callback_collection::Subscription<TypeId, GlobalObservationCallback>),
4171    FocusObservation(callback_collection::Subscription<usize, FocusObservationCallback>),
4172    WindowActivationObservation(callback_collection::Subscription<usize, WindowActivationCallback>),
4173    WindowFullscreenObservation(callback_collection::Subscription<usize, WindowFullscreenCallback>),
4174    WindowBoundsObservation(callback_collection::Subscription<usize, WindowBoundsCallback>),
4175    KeystrokeObservation(callback_collection::Subscription<usize, KeystrokeCallback>),
4176    ReleaseObservation(callback_collection::Subscription<usize, ReleaseObservationCallback>),
4177    ActionObservation(callback_collection::Subscription<(), ActionObservationCallback>),
4178    ActiveLabeledTasksObservation(
4179        callback_collection::Subscription<(), ActiveLabeledTasksCallback>,
4180    ),
4181}
4182
4183impl Subscription {
4184    pub fn id(&self) -> usize {
4185        match self {
4186            Subscription::Subscription(subscription) => subscription.id(),
4187            Subscription::Observation(subscription) => subscription.id(),
4188            Subscription::GlobalSubscription(subscription) => subscription.id(),
4189            Subscription::GlobalObservation(subscription) => subscription.id(),
4190            Subscription::FocusObservation(subscription) => subscription.id(),
4191            Subscription::WindowActivationObservation(subscription) => subscription.id(),
4192            Subscription::WindowFullscreenObservation(subscription) => subscription.id(),
4193            Subscription::WindowBoundsObservation(subscription) => subscription.id(),
4194            Subscription::KeystrokeObservation(subscription) => subscription.id(),
4195            Subscription::ReleaseObservation(subscription) => subscription.id(),
4196            Subscription::ActionObservation(subscription) => subscription.id(),
4197            Subscription::ActiveLabeledTasksObservation(subscription) => subscription.id(),
4198        }
4199    }
4200
4201    pub fn detach(&mut self) {
4202        match self {
4203            Subscription::Subscription(subscription) => subscription.detach(),
4204            Subscription::GlobalSubscription(subscription) => subscription.detach(),
4205            Subscription::Observation(subscription) => subscription.detach(),
4206            Subscription::GlobalObservation(subscription) => subscription.detach(),
4207            Subscription::FocusObservation(subscription) => subscription.detach(),
4208            Subscription::KeystrokeObservation(subscription) => subscription.detach(),
4209            Subscription::WindowActivationObservation(subscription) => subscription.detach(),
4210            Subscription::WindowFullscreenObservation(subscription) => subscription.detach(),
4211            Subscription::WindowBoundsObservation(subscription) => subscription.detach(),
4212            Subscription::ReleaseObservation(subscription) => subscription.detach(),
4213            Subscription::ActionObservation(subscription) => subscription.detach(),
4214            Subscription::ActiveLabeledTasksObservation(subscription) => subscription.detach(),
4215        }
4216    }
4217}
4218
4219#[cfg(test)]
4220mod tests {
4221    use super::*;
4222    use crate::{
4223        actions,
4224        elements::*,
4225        impl_actions,
4226        platform::{MouseButton, MouseButtonEvent},
4227        window::ChildView,
4228    };
4229    use itertools::Itertools;
4230    use postage::{sink::Sink, stream::Stream};
4231    use serde::Deserialize;
4232    use smol::future::poll_once;
4233    use std::{
4234        cell::Cell,
4235        sync::atomic::{AtomicBool, AtomicUsize, Ordering::SeqCst},
4236    };
4237
4238    #[crate::test(self)]
4239    fn test_model_handles(cx: &mut AppContext) {
4240        struct Model {
4241            other: Option<ModelHandle<Model>>,
4242            events: Vec<String>,
4243        }
4244
4245        impl Entity for Model {
4246            type Event = usize;
4247        }
4248
4249        impl Model {
4250            fn new(other: Option<ModelHandle<Self>>, cx: &mut ModelContext<Self>) -> Self {
4251                if let Some(other) = other.as_ref() {
4252                    cx.observe(other, |me, _, _| {
4253                        me.events.push("notified".into());
4254                    })
4255                    .detach();
4256                    cx.subscribe(other, |me, _, event, _| {
4257                        me.events.push(format!("observed event {}", event));
4258                    })
4259                    .detach();
4260                }
4261
4262                Self {
4263                    other,
4264                    events: Vec::new(),
4265                }
4266            }
4267        }
4268
4269        let handle_1 = cx.add_model(|cx| Model::new(None, cx));
4270        let handle_2 = cx.add_model(|cx| Model::new(Some(handle_1.clone()), cx));
4271        assert_eq!(cx.models.len(), 2);
4272
4273        handle_1.update(cx, |model, cx| {
4274            model.events.push("updated".into());
4275            cx.emit(1);
4276            cx.notify();
4277            cx.emit(2);
4278        });
4279        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
4280        assert_eq!(
4281            handle_2.read(cx).events,
4282            vec![
4283                "observed event 1".to_string(),
4284                "notified".to_string(),
4285                "observed event 2".to_string(),
4286            ]
4287        );
4288
4289        handle_2.update(cx, |model, _| {
4290            drop(handle_1);
4291            model.other.take();
4292        });
4293
4294        assert_eq!(cx.models.len(), 1);
4295        assert!(cx.subscriptions.is_empty());
4296        assert!(cx.observations.is_empty());
4297    }
4298
4299    #[crate::test(self)]
4300    fn test_model_events(cx: &mut AppContext) {
4301        #[derive(Default)]
4302        struct Model {
4303            events: Vec<usize>,
4304        }
4305
4306        impl Entity for Model {
4307            type Event = usize;
4308        }
4309
4310        let handle_1 = cx.add_model(|_| Model::default());
4311        let handle_2 = cx.add_model(|_| Model::default());
4312
4313        handle_1.update(cx, |_, cx| {
4314            cx.subscribe(&handle_2, move |model: &mut Model, emitter, event, cx| {
4315                model.events.push(*event);
4316
4317                cx.subscribe(&emitter, |model, _, event, _| {
4318                    model.events.push(*event * 2);
4319                })
4320                .detach();
4321            })
4322            .detach();
4323        });
4324
4325        handle_2.update(cx, |_, c| c.emit(7));
4326        assert_eq!(handle_1.read(cx).events, vec![7]);
4327
4328        handle_2.update(cx, |_, c| c.emit(5));
4329        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10]);
4330    }
4331
4332    #[crate::test(self)]
4333    fn test_model_emit_before_subscribe_in_same_update_cycle(cx: &mut AppContext) {
4334        #[derive(Default)]
4335        struct Model;
4336
4337        impl Entity for Model {
4338            type Event = ();
4339        }
4340
4341        let events = Rc::new(RefCell::new(Vec::new()));
4342        cx.add_model(|cx| {
4343            drop(cx.subscribe(&cx.handle(), {
4344                let events = events.clone();
4345                move |_, _, _, _| events.borrow_mut().push("dropped before flush")
4346            }));
4347            cx.subscribe(&cx.handle(), {
4348                let events = events.clone();
4349                move |_, _, _, _| events.borrow_mut().push("before emit")
4350            })
4351            .detach();
4352            cx.emit(());
4353            cx.subscribe(&cx.handle(), {
4354                let events = events.clone();
4355                move |_, _, _, _| events.borrow_mut().push("after emit")
4356            })
4357            .detach();
4358            Model
4359        });
4360        assert_eq!(*events.borrow(), ["before emit"]);
4361    }
4362
4363    #[crate::test(self)]
4364    fn test_observe_and_notify_from_model(cx: &mut AppContext) {
4365        #[derive(Default)]
4366        struct Model {
4367            count: usize,
4368            events: Vec<usize>,
4369        }
4370
4371        impl Entity for Model {
4372            type Event = ();
4373        }
4374
4375        let handle_1 = cx.add_model(|_| Model::default());
4376        let handle_2 = cx.add_model(|_| Model::default());
4377
4378        handle_1.update(cx, |_, c| {
4379            c.observe(&handle_2, move |model, observed, c| {
4380                model.events.push(observed.read(c).count);
4381                c.observe(&observed, |model, observed, c| {
4382                    model.events.push(observed.read(c).count * 2);
4383                })
4384                .detach();
4385            })
4386            .detach();
4387        });
4388
4389        handle_2.update(cx, |model, c| {
4390            model.count = 7;
4391            c.notify()
4392        });
4393        assert_eq!(handle_1.read(cx).events, vec![7]);
4394
4395        handle_2.update(cx, |model, c| {
4396            model.count = 5;
4397            c.notify()
4398        });
4399        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10])
4400    }
4401
4402    #[crate::test(self)]
4403    fn test_model_notify_before_observe_in_same_update_cycle(cx: &mut AppContext) {
4404        #[derive(Default)]
4405        struct Model;
4406
4407        impl Entity for Model {
4408            type Event = ();
4409        }
4410
4411        let events = Rc::new(RefCell::new(Vec::new()));
4412        cx.add_model(|cx| {
4413            drop(cx.observe(&cx.handle(), {
4414                let events = events.clone();
4415                move |_, _, _| events.borrow_mut().push("dropped before flush")
4416            }));
4417            cx.observe(&cx.handle(), {
4418                let events = events.clone();
4419                move |_, _, _| events.borrow_mut().push("before notify")
4420            })
4421            .detach();
4422            cx.notify();
4423            cx.observe(&cx.handle(), {
4424                let events = events.clone();
4425                move |_, _, _| events.borrow_mut().push("after notify")
4426            })
4427            .detach();
4428            Model
4429        });
4430        assert_eq!(*events.borrow(), ["before notify"]);
4431    }
4432
4433    #[crate::test(self)]
4434    fn test_defer_and_after_window_update(cx: &mut TestAppContext) {
4435        struct View {
4436            render_count: usize,
4437        }
4438
4439        impl Entity for View {
4440            type Event = usize;
4441        }
4442
4443        impl super::View for View {
4444            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
4445                post_inc(&mut self.render_count);
4446                Empty::new().into_any()
4447            }
4448
4449            fn ui_name() -> &'static str {
4450                "View"
4451            }
4452        }
4453
4454        let (_, view) = cx.add_window(|_| View { render_count: 0 });
4455        let called_defer = Rc::new(AtomicBool::new(false));
4456        let called_after_window_update = Rc::new(AtomicBool::new(false));
4457
4458        view.update(cx, |this, cx| {
4459            assert_eq!(this.render_count, 1);
4460            cx.defer({
4461                let called_defer = called_defer.clone();
4462                move |this, _| {
4463                    assert_eq!(this.render_count, 1);
4464                    called_defer.store(true, SeqCst);
4465                }
4466            });
4467            cx.after_window_update({
4468                let called_after_window_update = called_after_window_update.clone();
4469                move |this, cx| {
4470                    assert_eq!(this.render_count, 2);
4471                    called_after_window_update.store(true, SeqCst);
4472                    cx.notify();
4473                }
4474            });
4475            assert!(!called_defer.load(SeqCst));
4476            assert!(!called_after_window_update.load(SeqCst));
4477            cx.notify();
4478        });
4479
4480        assert!(called_defer.load(SeqCst));
4481        assert!(called_after_window_update.load(SeqCst));
4482        assert_eq!(view.read_with(cx, |view, _| view.render_count), 3);
4483    }
4484
4485    #[crate::test(self)]
4486    fn test_view_handles(cx: &mut TestAppContext) {
4487        struct View {
4488            other: Option<ViewHandle<View>>,
4489            events: Vec<String>,
4490        }
4491
4492        impl Entity for View {
4493            type Event = usize;
4494        }
4495
4496        impl super::View for View {
4497            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
4498                Empty::new().into_any()
4499            }
4500
4501            fn ui_name() -> &'static str {
4502                "View"
4503            }
4504        }
4505
4506        impl View {
4507            fn new(other: Option<ViewHandle<View>>, cx: &mut ViewContext<Self>) -> Self {
4508                if let Some(other) = other.as_ref() {
4509                    cx.subscribe(other, |me, _, event, _| {
4510                        me.events.push(format!("observed event {}", event));
4511                    })
4512                    .detach();
4513                }
4514                Self {
4515                    other,
4516                    events: Vec::new(),
4517                }
4518            }
4519        }
4520
4521        let (window_id, _root_view) = cx.add_window(|cx| View::new(None, cx));
4522        let handle_1 = cx.add_view(window_id, |cx| View::new(None, cx));
4523        let handle_2 = cx.add_view(window_id, |cx| View::new(Some(handle_1.clone()), cx));
4524        assert_eq!(cx.read(|cx| cx.views.len()), 3);
4525
4526        handle_1.update(cx, |view, cx| {
4527            view.events.push("updated".into());
4528            cx.emit(1);
4529            cx.emit(2);
4530        });
4531        handle_1.read_with(cx, |view, _| {
4532            assert_eq!(view.events, vec!["updated".to_string()]);
4533        });
4534        handle_2.read_with(cx, |view, _| {
4535            assert_eq!(
4536                view.events,
4537                vec![
4538                    "observed event 1".to_string(),
4539                    "observed event 2".to_string(),
4540                ]
4541            );
4542        });
4543
4544        handle_2.update(cx, |view, _| {
4545            drop(handle_1);
4546            view.other.take();
4547        });
4548
4549        cx.read(|cx| {
4550            assert_eq!(cx.views.len(), 2);
4551            assert!(cx.subscriptions.is_empty());
4552            assert!(cx.observations.is_empty());
4553        });
4554    }
4555
4556    #[crate::test(self)]
4557    fn test_add_window(cx: &mut AppContext) {
4558        struct View {
4559            mouse_down_count: Arc<AtomicUsize>,
4560        }
4561
4562        impl Entity for View {
4563            type Event = ();
4564        }
4565
4566        impl super::View for View {
4567            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
4568                enum Handler {}
4569                let mouse_down_count = self.mouse_down_count.clone();
4570                MouseEventHandler::<Handler, _>::new(0, cx, |_, _| Empty::new())
4571                    .on_down(MouseButton::Left, move |_, _, _| {
4572                        mouse_down_count.fetch_add(1, SeqCst);
4573                    })
4574                    .into_any()
4575            }
4576
4577            fn ui_name() -> &'static str {
4578                "View"
4579            }
4580        }
4581
4582        let mouse_down_count = Arc::new(AtomicUsize::new(0));
4583        let (window_id, _) = cx.add_window(Default::default(), |_| View {
4584            mouse_down_count: mouse_down_count.clone(),
4585        });
4586
4587        cx.update_window(window_id, |cx| {
4588            // Ensure window's root element is in a valid lifecycle state.
4589            cx.dispatch_event(
4590                Event::MouseDown(MouseButtonEvent {
4591                    position: Default::default(),
4592                    button: MouseButton::Left,
4593                    modifiers: Default::default(),
4594                    click_count: 1,
4595                }),
4596                false,
4597            );
4598            assert_eq!(mouse_down_count.load(SeqCst), 1);
4599        });
4600    }
4601
4602    #[crate::test(self)]
4603    fn test_entity_release_hooks(cx: &mut AppContext) {
4604        struct Model {
4605            released: Rc<Cell<bool>>,
4606        }
4607
4608        struct View {
4609            released: Rc<Cell<bool>>,
4610        }
4611
4612        impl Entity for Model {
4613            type Event = ();
4614
4615            fn release(&mut self, _: &mut AppContext) {
4616                self.released.set(true);
4617            }
4618        }
4619
4620        impl Entity for View {
4621            type Event = ();
4622
4623            fn release(&mut self, _: &mut AppContext) {
4624                self.released.set(true);
4625            }
4626        }
4627
4628        impl super::View for View {
4629            fn ui_name() -> &'static str {
4630                "View"
4631            }
4632
4633            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
4634                Empty::new().into_any()
4635            }
4636        }
4637
4638        let model_released = Rc::new(Cell::new(false));
4639        let model_release_observed = Rc::new(Cell::new(false));
4640        let view_released = Rc::new(Cell::new(false));
4641        let view_release_observed = Rc::new(Cell::new(false));
4642
4643        let model = cx.add_model(|_| Model {
4644            released: model_released.clone(),
4645        });
4646        let (window_id, view) = cx.add_window(Default::default(), |_| View {
4647            released: view_released.clone(),
4648        });
4649        assert!(!model_released.get());
4650        assert!(!view_released.get());
4651
4652        cx.observe_release(&model, {
4653            let model_release_observed = model_release_observed.clone();
4654            move |_, _| model_release_observed.set(true)
4655        })
4656        .detach();
4657        cx.observe_release(&view, {
4658            let view_release_observed = view_release_observed.clone();
4659            move |_, _| view_release_observed.set(true)
4660        })
4661        .detach();
4662
4663        cx.update(move |_| {
4664            drop(model);
4665        });
4666        assert!(model_released.get());
4667        assert!(model_release_observed.get());
4668
4669        drop(view);
4670        cx.update_window(window_id, |cx| cx.remove_window());
4671        assert!(view_released.get());
4672        assert!(view_release_observed.get());
4673    }
4674
4675    #[crate::test(self)]
4676    fn test_view_events(cx: &mut TestAppContext) {
4677        struct Model;
4678
4679        impl Entity for Model {
4680            type Event = String;
4681        }
4682
4683        let (window_id, handle_1) = cx.add_window(|_| TestView::default());
4684        let handle_2 = cx.add_view(window_id, |_| TestView::default());
4685        let handle_3 = cx.add_model(|_| Model);
4686
4687        handle_1.update(cx, |_, cx| {
4688            cx.subscribe(&handle_2, move |me, emitter, event, cx| {
4689                me.events.push(event.clone());
4690
4691                cx.subscribe(&emitter, |me, _, event, _| {
4692                    me.events.push(format!("{event} from inner"));
4693                })
4694                .detach();
4695            })
4696            .detach();
4697
4698            cx.subscribe(&handle_3, |me, _, event, _| {
4699                me.events.push(event.clone());
4700            })
4701            .detach();
4702        });
4703
4704        handle_2.update(cx, |_, c| c.emit("7".into()));
4705        handle_1.read_with(cx, |view, _| assert_eq!(view.events, ["7"]));
4706
4707        handle_2.update(cx, |_, c| c.emit("5".into()));
4708        handle_1.read_with(cx, |view, _| {
4709            assert_eq!(view.events, ["7", "5", "5 from inner"])
4710        });
4711
4712        handle_3.update(cx, |_, c| c.emit("9".into()));
4713        handle_1.read_with(cx, |view, _| {
4714            assert_eq!(view.events, ["7", "5", "5 from inner", "9"])
4715        });
4716    }
4717
4718    #[crate::test(self)]
4719    fn test_global_events(cx: &mut AppContext) {
4720        #[derive(Clone, Debug, Eq, PartialEq)]
4721        struct GlobalEvent(u64);
4722
4723        let events = Rc::new(RefCell::new(Vec::new()));
4724        let first_subscription;
4725        let second_subscription;
4726
4727        {
4728            let events = events.clone();
4729            first_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
4730                events.borrow_mut().push(("First", e.clone()));
4731            });
4732        }
4733
4734        {
4735            let events = events.clone();
4736            second_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
4737                events.borrow_mut().push(("Second", e.clone()));
4738            });
4739        }
4740
4741        cx.update(|cx| {
4742            cx.emit_global(GlobalEvent(1));
4743            cx.emit_global(GlobalEvent(2));
4744        });
4745
4746        drop(first_subscription);
4747
4748        cx.update(|cx| {
4749            cx.emit_global(GlobalEvent(3));
4750        });
4751
4752        drop(second_subscription);
4753
4754        cx.update(|cx| {
4755            cx.emit_global(GlobalEvent(4));
4756        });
4757
4758        assert_eq!(
4759            &*events.borrow(),
4760            &[
4761                ("First", GlobalEvent(1)),
4762                ("Second", GlobalEvent(1)),
4763                ("First", GlobalEvent(2)),
4764                ("Second", GlobalEvent(2)),
4765                ("Second", GlobalEvent(3)),
4766            ]
4767        );
4768    }
4769
4770    #[crate::test(self)]
4771    fn test_global_events_emitted_before_subscription_in_same_update_cycle(cx: &mut AppContext) {
4772        let events = Rc::new(RefCell::new(Vec::new()));
4773        cx.update(|cx| {
4774            {
4775                let events = events.clone();
4776                drop(cx.subscribe_global(move |_: &(), _| {
4777                    events.borrow_mut().push("dropped before emit");
4778                }));
4779            }
4780
4781            {
4782                let events = events.clone();
4783                cx.subscribe_global(move |_: &(), _| {
4784                    events.borrow_mut().push("before emit");
4785                })
4786                .detach();
4787            }
4788
4789            cx.emit_global(());
4790
4791            {
4792                let events = events.clone();
4793                cx.subscribe_global(move |_: &(), _| {
4794                    events.borrow_mut().push("after emit");
4795                })
4796                .detach();
4797            }
4798        });
4799
4800        assert_eq!(*events.borrow(), ["before emit"]);
4801    }
4802
4803    #[crate::test(self)]
4804    fn test_global_nested_events(cx: &mut AppContext) {
4805        #[derive(Clone, Debug, Eq, PartialEq)]
4806        struct GlobalEvent(u64);
4807
4808        let events = Rc::new(RefCell::new(Vec::new()));
4809
4810        {
4811            let events = events.clone();
4812            cx.subscribe_global(move |e: &GlobalEvent, cx| {
4813                events.borrow_mut().push(("Outer", e.clone()));
4814
4815                if e.0 == 1 {
4816                    let events = events.clone();
4817                    cx.subscribe_global(move |e: &GlobalEvent, _| {
4818                        events.borrow_mut().push(("Inner", e.clone()));
4819                    })
4820                    .detach();
4821                }
4822            })
4823            .detach();
4824        }
4825
4826        cx.update(|cx| {
4827            cx.emit_global(GlobalEvent(1));
4828            cx.emit_global(GlobalEvent(2));
4829            cx.emit_global(GlobalEvent(3));
4830        });
4831        cx.update(|cx| {
4832            cx.emit_global(GlobalEvent(4));
4833        });
4834
4835        assert_eq!(
4836            &*events.borrow(),
4837            &[
4838                ("Outer", GlobalEvent(1)),
4839                ("Outer", GlobalEvent(2)),
4840                ("Outer", GlobalEvent(3)),
4841                ("Outer", GlobalEvent(4)),
4842                ("Inner", GlobalEvent(4)),
4843            ]
4844        );
4845    }
4846
4847    #[crate::test(self)]
4848    fn test_global(cx: &mut AppContext) {
4849        type Global = usize;
4850
4851        let observation_count = Rc::new(RefCell::new(0));
4852        let subscription = cx.observe_global::<Global, _>({
4853            let observation_count = observation_count.clone();
4854            move |_| {
4855                *observation_count.borrow_mut() += 1;
4856            }
4857        });
4858
4859        assert!(!cx.has_global::<Global>());
4860        assert_eq!(cx.default_global::<Global>(), &0);
4861        assert_eq!(*observation_count.borrow(), 1);
4862        assert!(cx.has_global::<Global>());
4863        assert_eq!(
4864            cx.update_global::<Global, _, _>(|global, _| {
4865                *global = 1;
4866                "Update Result"
4867            }),
4868            "Update Result"
4869        );
4870        assert_eq!(*observation_count.borrow(), 2);
4871        assert_eq!(cx.global::<Global>(), &1);
4872
4873        drop(subscription);
4874        cx.update_global::<Global, _, _>(|global, _| {
4875            *global = 2;
4876        });
4877        assert_eq!(*observation_count.borrow(), 2);
4878
4879        type OtherGlobal = f32;
4880
4881        let observation_count = Rc::new(RefCell::new(0));
4882        cx.observe_global::<OtherGlobal, _>({
4883            let observation_count = observation_count.clone();
4884            move |_| {
4885                *observation_count.borrow_mut() += 1;
4886            }
4887        })
4888        .detach();
4889
4890        assert_eq!(
4891            cx.update_default_global::<OtherGlobal, _, _>(|global, _| {
4892                assert_eq!(global, &0.0);
4893                *global = 2.0;
4894                "Default update result"
4895            }),
4896            "Default update result"
4897        );
4898        assert_eq!(cx.global::<OtherGlobal>(), &2.0);
4899        assert_eq!(*observation_count.borrow(), 1);
4900    }
4901
4902    #[crate::test(self)]
4903    fn test_dropping_subscribers(cx: &mut TestAppContext) {
4904        struct Model;
4905
4906        impl Entity for Model {
4907            type Event = ();
4908        }
4909
4910        let (window_id, _root_view) = cx.add_window(|_| TestView::default());
4911        let observing_view = cx.add_view(window_id, |_| TestView::default());
4912        let emitting_view = cx.add_view(window_id, |_| TestView::default());
4913        let observing_model = cx.add_model(|_| Model);
4914        let observed_model = cx.add_model(|_| Model);
4915
4916        observing_view.update(cx, |_, cx| {
4917            cx.subscribe(&emitting_view, |_, _, _, _| {}).detach();
4918            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
4919        });
4920        observing_model.update(cx, |_, cx| {
4921            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
4922        });
4923
4924        cx.update(|_| {
4925            drop(observing_view);
4926            drop(observing_model);
4927        });
4928
4929        emitting_view.update(cx, |_, cx| cx.emit(Default::default()));
4930        observed_model.update(cx, |_, cx| cx.emit(()));
4931    }
4932
4933    #[crate::test(self)]
4934    fn test_view_emit_before_subscribe_in_same_update_cycle(cx: &mut AppContext) {
4935        let (_, view) = cx.add_window::<TestView, _>(Default::default(), |cx| {
4936            drop(cx.subscribe(&cx.handle(), {
4937                move |this, _, _, _| this.events.push("dropped before flush".into())
4938            }));
4939            cx.subscribe(&cx.handle(), {
4940                move |this, _, _, _| this.events.push("before emit".into())
4941            })
4942            .detach();
4943            cx.emit("the event".into());
4944            cx.subscribe(&cx.handle(), {
4945                move |this, _, _, _| this.events.push("after emit".into())
4946            })
4947            .detach();
4948            TestView { events: Vec::new() }
4949        });
4950
4951        assert_eq!(view.read(cx).events, ["before emit"]);
4952    }
4953
4954    #[crate::test(self)]
4955    fn test_observe_and_notify_from_view(cx: &mut TestAppContext) {
4956        #[derive(Default)]
4957        struct Model {
4958            state: String,
4959        }
4960
4961        impl Entity for Model {
4962            type Event = ();
4963        }
4964
4965        let (_, view) = cx.add_window(|_| TestView::default());
4966        let model = cx.add_model(|_| Model {
4967            state: "old-state".into(),
4968        });
4969
4970        view.update(cx, |_, c| {
4971            c.observe(&model, |me, observed, cx| {
4972                me.events.push(observed.read(cx).state.clone())
4973            })
4974            .detach();
4975        });
4976
4977        model.update(cx, |model, cx| {
4978            model.state = "new-state".into();
4979            cx.notify();
4980        });
4981        view.read_with(cx, |view, _| assert_eq!(view.events, ["new-state"]));
4982    }
4983
4984    #[crate::test(self)]
4985    fn test_view_notify_before_observe_in_same_update_cycle(cx: &mut AppContext) {
4986        let (_, view) = cx.add_window::<TestView, _>(Default::default(), |cx| {
4987            drop(cx.observe(&cx.handle(), {
4988                move |this, _, _| this.events.push("dropped before flush".into())
4989            }));
4990            cx.observe(&cx.handle(), {
4991                move |this, _, _| this.events.push("before notify".into())
4992            })
4993            .detach();
4994            cx.notify();
4995            cx.observe(&cx.handle(), {
4996                move |this, _, _| this.events.push("after notify".into())
4997            })
4998            .detach();
4999            TestView { events: Vec::new() }
5000        });
5001
5002        assert_eq!(view.read(cx).events, ["before notify"]);
5003    }
5004
5005    #[crate::test(self)]
5006    fn test_notify_and_drop_observe_subscription_in_same_update_cycle(cx: &mut TestAppContext) {
5007        struct Model;
5008        impl Entity for Model {
5009            type Event = ();
5010        }
5011
5012        let model = cx.add_model(|_| Model);
5013        let (_, view) = cx.add_window(|_| TestView::default());
5014
5015        view.update(cx, |_, cx| {
5016            model.update(cx, |_, cx| cx.notify());
5017            drop(cx.observe(&model, move |this, _, _| {
5018                this.events.push("model notified".into());
5019            }));
5020            model.update(cx, |_, cx| cx.notify());
5021        });
5022
5023        for _ in 0..3 {
5024            model.update(cx, |_, cx| cx.notify());
5025        }
5026        view.read_with(cx, |view, _| assert_eq!(view.events, Vec::<&str>::new()));
5027    }
5028
5029    #[crate::test(self)]
5030    fn test_dropping_observers(cx: &mut TestAppContext) {
5031        struct Model;
5032
5033        impl Entity for Model {
5034            type Event = ();
5035        }
5036
5037        let (window_id, _root_view) = cx.add_window(|_| TestView::default());
5038        let observing_view = cx.add_view(window_id, |_| TestView::default());
5039        let observing_model = cx.add_model(|_| Model);
5040        let observed_model = cx.add_model(|_| Model);
5041
5042        observing_view.update(cx, |_, cx| {
5043            cx.observe(&observed_model, |_, _, _| {}).detach();
5044        });
5045        observing_model.update(cx, |_, cx| {
5046            cx.observe(&observed_model, |_, _, _| {}).detach();
5047        });
5048
5049        cx.update(|_| {
5050            drop(observing_view);
5051            drop(observing_model);
5052        });
5053
5054        observed_model.update(cx, |_, cx| cx.notify());
5055    }
5056
5057    #[crate::test(self)]
5058    fn test_dropping_subscriptions_during_callback(cx: &mut TestAppContext) {
5059        struct Model;
5060
5061        impl Entity for Model {
5062            type Event = u64;
5063        }
5064
5065        // Events
5066        let observing_model = cx.add_model(|_| Model);
5067        let observed_model = cx.add_model(|_| Model);
5068
5069        let events = Rc::new(RefCell::new(Vec::new()));
5070
5071        observing_model.update(cx, |_, cx| {
5072            let events = events.clone();
5073            let subscription = Rc::new(RefCell::new(None));
5074            *subscription.borrow_mut() = Some(cx.subscribe(&observed_model, {
5075                let subscription = subscription.clone();
5076                move |_, _, e, _| {
5077                    subscription.borrow_mut().take();
5078                    events.borrow_mut().push(*e);
5079                }
5080            }));
5081        });
5082
5083        observed_model.update(cx, |_, cx| {
5084            cx.emit(1);
5085            cx.emit(2);
5086        });
5087
5088        assert_eq!(*events.borrow(), [1]);
5089
5090        // Global Events
5091        #[derive(Clone, Debug, Eq, PartialEq)]
5092        struct GlobalEvent(u64);
5093
5094        let events = Rc::new(RefCell::new(Vec::new()));
5095
5096        {
5097            let events = events.clone();
5098            let subscription = Rc::new(RefCell::new(None));
5099            *subscription.borrow_mut() = Some(cx.subscribe_global({
5100                let subscription = subscription.clone();
5101                move |e: &GlobalEvent, _| {
5102                    subscription.borrow_mut().take();
5103                    events.borrow_mut().push(e.clone());
5104                }
5105            }));
5106        }
5107
5108        cx.update(|cx| {
5109            cx.emit_global(GlobalEvent(1));
5110            cx.emit_global(GlobalEvent(2));
5111        });
5112
5113        assert_eq!(*events.borrow(), [GlobalEvent(1)]);
5114
5115        // Model Observation
5116        let observing_model = cx.add_model(|_| Model);
5117        let observed_model = cx.add_model(|_| Model);
5118
5119        let observation_count = Rc::new(RefCell::new(0));
5120
5121        observing_model.update(cx, |_, cx| {
5122            let observation_count = observation_count.clone();
5123            let subscription = Rc::new(RefCell::new(None));
5124            *subscription.borrow_mut() = Some(cx.observe(&observed_model, {
5125                let subscription = subscription.clone();
5126                move |_, _, _| {
5127                    subscription.borrow_mut().take();
5128                    *observation_count.borrow_mut() += 1;
5129                }
5130            }));
5131        });
5132
5133        observed_model.update(cx, |_, cx| {
5134            cx.notify();
5135        });
5136
5137        observed_model.update(cx, |_, cx| {
5138            cx.notify();
5139        });
5140
5141        assert_eq!(*observation_count.borrow(), 1);
5142
5143        // View Observation
5144        struct View;
5145
5146        impl Entity for View {
5147            type Event = ();
5148        }
5149
5150        impl super::View for View {
5151            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
5152                Empty::new().into_any()
5153            }
5154
5155            fn ui_name() -> &'static str {
5156                "View"
5157            }
5158        }
5159
5160        let (window_id, _root_view) = cx.add_window(|_| View);
5161        let observing_view = cx.add_view(window_id, |_| View);
5162        let observed_view = cx.add_view(window_id, |_| View);
5163
5164        let observation_count = Rc::new(RefCell::new(0));
5165        observing_view.update(cx, |_, cx| {
5166            let observation_count = observation_count.clone();
5167            let subscription = Rc::new(RefCell::new(None));
5168            *subscription.borrow_mut() = Some(cx.observe(&observed_view, {
5169                let subscription = subscription.clone();
5170                move |_, _, _| {
5171                    subscription.borrow_mut().take();
5172                    *observation_count.borrow_mut() += 1;
5173                }
5174            }));
5175        });
5176
5177        observed_view.update(cx, |_, cx| {
5178            cx.notify();
5179        });
5180
5181        observed_view.update(cx, |_, cx| {
5182            cx.notify();
5183        });
5184
5185        assert_eq!(*observation_count.borrow(), 1);
5186
5187        // Global Observation
5188        let observation_count = Rc::new(RefCell::new(0));
5189        let subscription = Rc::new(RefCell::new(None));
5190        *subscription.borrow_mut() = Some(cx.observe_global::<(), _>({
5191            let observation_count = observation_count.clone();
5192            let subscription = subscription.clone();
5193            move |_| {
5194                subscription.borrow_mut().take();
5195                *observation_count.borrow_mut() += 1;
5196            }
5197        }));
5198
5199        cx.update(|cx| {
5200            cx.default_global::<()>();
5201            cx.set_global(());
5202        });
5203        assert_eq!(*observation_count.borrow(), 1);
5204    }
5205
5206    #[crate::test(self)]
5207    fn test_focus(cx: &mut TestAppContext) {
5208        struct View {
5209            name: String,
5210            events: Arc<Mutex<Vec<String>>>,
5211            child: Option<AnyViewHandle>,
5212        }
5213
5214        impl Entity for View {
5215            type Event = ();
5216        }
5217
5218        impl super::View for View {
5219            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5220                self.child
5221                    .as_ref()
5222                    .map(|child| ChildView::new(child, cx).into_any())
5223                    .unwrap_or(Empty::new().into_any())
5224            }
5225
5226            fn ui_name() -> &'static str {
5227                "View"
5228            }
5229
5230            fn focus_in(&mut self, focused: AnyViewHandle, cx: &mut ViewContext<Self>) {
5231                if cx.handle().id() == focused.id() {
5232                    self.events.lock().push(format!("{} focused", &self.name));
5233                }
5234            }
5235
5236            fn focus_out(&mut self, blurred: AnyViewHandle, cx: &mut ViewContext<Self>) {
5237                if cx.handle().id() == blurred.id() {
5238                    self.events.lock().push(format!("{} blurred", &self.name));
5239                }
5240            }
5241        }
5242
5243        let view_events: Arc<Mutex<Vec<String>>> = Default::default();
5244        let (window_id, view_1) = cx.add_window(|_| View {
5245            events: view_events.clone(),
5246            name: "view 1".to_string(),
5247            child: None,
5248        });
5249        let view_2 = cx
5250            .update_window(window_id, |cx| {
5251                let view_2 = cx.add_view(|_| View {
5252                    events: view_events.clone(),
5253                    name: "view 2".to_string(),
5254                    child: None,
5255                });
5256                view_1.update(cx, |view_1, cx| {
5257                    view_1.child = Some(view_2.clone().into_any());
5258                    cx.notify();
5259                });
5260                view_2
5261            })
5262            .unwrap();
5263
5264        let observed_events: Arc<Mutex<Vec<String>>> = Default::default();
5265        view_1.update(cx, |_, cx| {
5266            cx.observe_focus(&view_2, {
5267                let observed_events = observed_events.clone();
5268                move |this, view, focused, cx| {
5269                    let label = if focused { "focus" } else { "blur" };
5270                    observed_events.lock().push(format!(
5271                        "{} observed {}'s {}",
5272                        this.name,
5273                        view.read(cx).name,
5274                        label
5275                    ))
5276                }
5277            })
5278            .detach();
5279        });
5280        view_2.update(cx, |_, cx| {
5281            cx.observe_focus(&view_1, {
5282                let observed_events = observed_events.clone();
5283                move |this, view, focused, cx| {
5284                    let label = if focused { "focus" } else { "blur" };
5285                    observed_events.lock().push(format!(
5286                        "{} observed {}'s {}",
5287                        this.name,
5288                        view.read(cx).name,
5289                        label
5290                    ))
5291                }
5292            })
5293            .detach();
5294        });
5295        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
5296        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
5297
5298        view_1.update(cx, |_, cx| {
5299            // Ensure only the last focus event is honored.
5300            cx.focus(&view_2);
5301            cx.focus(&view_1);
5302            cx.focus(&view_2);
5303        });
5304
5305        cx.read_window(window_id, |cx| {
5306            assert!(cx.is_child_focused(&view_1));
5307            assert!(!cx.is_child_focused(&view_2));
5308        });
5309        assert_eq!(
5310            mem::take(&mut *view_events.lock()),
5311            ["view 1 blurred", "view 2 focused"],
5312        );
5313        assert_eq!(
5314            mem::take(&mut *observed_events.lock()),
5315            [
5316                "view 2 observed view 1's blur",
5317                "view 1 observed view 2's focus"
5318            ]
5319        );
5320
5321        view_1.update(cx, |_, cx| cx.focus(&view_1));
5322        cx.read_window(window_id, |cx| {
5323            assert!(!cx.is_child_focused(&view_1));
5324            assert!(!cx.is_child_focused(&view_2));
5325        });
5326        assert_eq!(
5327            mem::take(&mut *view_events.lock()),
5328            ["view 2 blurred", "view 1 focused"],
5329        );
5330        assert_eq!(
5331            mem::take(&mut *observed_events.lock()),
5332            [
5333                "view 1 observed view 2's blur",
5334                "view 2 observed view 1's focus"
5335            ]
5336        );
5337
5338        view_1.update(cx, |_, cx| cx.focus(&view_2));
5339        assert_eq!(
5340            mem::take(&mut *view_events.lock()),
5341            ["view 1 blurred", "view 2 focused"],
5342        );
5343        assert_eq!(
5344            mem::take(&mut *observed_events.lock()),
5345            [
5346                "view 2 observed view 1's blur",
5347                "view 1 observed view 2's focus"
5348            ]
5349        );
5350
5351        println!("=====================");
5352        view_1.update(cx, |view, _| {
5353            drop(view_2);
5354            view.child = None;
5355        });
5356        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
5357        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
5358    }
5359
5360    #[crate::test(self)]
5361    fn test_deserialize_actions(cx: &mut AppContext) {
5362        #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
5363        pub struct ComplexAction {
5364            arg: String,
5365            count: usize,
5366        }
5367
5368        actions!(test::something, [SimpleAction]);
5369        impl_actions!(test::something, [ComplexAction]);
5370
5371        cx.add_global_action(move |_: &SimpleAction, _: &mut AppContext| {});
5372        cx.add_global_action(move |_: &ComplexAction, _: &mut AppContext| {});
5373
5374        let action1 = cx
5375            .deserialize_action(
5376                "test::something::ComplexAction",
5377                Some(r#"{"arg": "a", "count": 5}"#),
5378            )
5379            .unwrap();
5380        let action2 = cx
5381            .deserialize_action("test::something::SimpleAction", None)
5382            .unwrap();
5383        assert_eq!(
5384            action1.as_any().downcast_ref::<ComplexAction>().unwrap(),
5385            &ComplexAction {
5386                arg: "a".to_string(),
5387                count: 5,
5388            }
5389        );
5390        assert_eq!(
5391            action2.as_any().downcast_ref::<SimpleAction>().unwrap(),
5392            &SimpleAction
5393        );
5394    }
5395
5396    #[crate::test(self)]
5397    fn test_dispatch_action(cx: &mut AppContext) {
5398        struct ViewA {
5399            id: usize,
5400            child: Option<AnyViewHandle>,
5401        }
5402
5403        impl Entity for ViewA {
5404            type Event = ();
5405        }
5406
5407        impl View for ViewA {
5408            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5409                self.child
5410                    .as_ref()
5411                    .map(|child| ChildView::new(child, cx).into_any())
5412                    .unwrap_or(Empty::new().into_any())
5413            }
5414
5415            fn ui_name() -> &'static str {
5416                "View"
5417            }
5418        }
5419
5420        struct ViewB {
5421            id: usize,
5422            child: Option<AnyViewHandle>,
5423        }
5424
5425        impl Entity for ViewB {
5426            type Event = ();
5427        }
5428
5429        impl View for ViewB {
5430            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5431                self.child
5432                    .as_ref()
5433                    .map(|child| ChildView::new(child, cx).into_any())
5434                    .unwrap_or(Empty::new().into_any())
5435            }
5436
5437            fn ui_name() -> &'static str {
5438                "View"
5439            }
5440        }
5441
5442        #[derive(Clone, Default, Deserialize, PartialEq)]
5443        pub struct Action(pub String);
5444
5445        impl_actions!(test, [Action]);
5446
5447        let actions = Rc::new(RefCell::new(Vec::new()));
5448
5449        cx.add_global_action({
5450            let actions = actions.clone();
5451            move |_: &Action, _: &mut AppContext| {
5452                actions.borrow_mut().push("global".to_string());
5453            }
5454        });
5455
5456        cx.add_action({
5457            let actions = actions.clone();
5458            move |view: &mut ViewA, action: &Action, cx| {
5459                assert_eq!(action.0, "bar");
5460                cx.propagate_action();
5461                actions.borrow_mut().push(format!("{} a", view.id));
5462            }
5463        });
5464
5465        cx.add_action({
5466            let actions = actions.clone();
5467            move |view: &mut ViewA, _: &Action, cx| {
5468                if view.id != 1 {
5469                    cx.add_view(|cx| {
5470                        cx.propagate_action(); // Still works on a nested ViewContext
5471                        ViewB { id: 5, child: None }
5472                    });
5473                }
5474                actions.borrow_mut().push(format!("{} b", view.id));
5475            }
5476        });
5477
5478        cx.add_action({
5479            let actions = actions.clone();
5480            move |view: &mut ViewB, _: &Action, cx| {
5481                cx.propagate_action();
5482                actions.borrow_mut().push(format!("{} c", view.id));
5483            }
5484        });
5485
5486        cx.add_action({
5487            let actions = actions.clone();
5488            move |view: &mut ViewB, _: &Action, cx| {
5489                cx.propagate_action();
5490                actions.borrow_mut().push(format!("{} d", view.id));
5491            }
5492        });
5493
5494        cx.capture_action({
5495            let actions = actions.clone();
5496            move |view: &mut ViewA, _: &Action, cx| {
5497                cx.propagate_action();
5498                actions.borrow_mut().push(format!("{} capture", view.id));
5499            }
5500        });
5501
5502        let observed_actions = Rc::new(RefCell::new(Vec::new()));
5503        cx.observe_actions({
5504            let observed_actions = observed_actions.clone();
5505            move |action_id, _| observed_actions.borrow_mut().push(action_id)
5506        })
5507        .detach();
5508
5509        let (window_id, view_1) =
5510            cx.add_window(Default::default(), |_| ViewA { id: 1, child: None });
5511        let view_2 = cx
5512            .update_window(window_id, |cx| {
5513                let child = cx.add_view(|_| ViewB { id: 2, child: None });
5514                view_1.update(cx, |view, cx| {
5515                    view.child = Some(child.clone().into_any());
5516                    cx.notify();
5517                });
5518                child
5519            })
5520            .unwrap();
5521        let view_3 = cx
5522            .update_window(window_id, |cx| {
5523                let child = cx.add_view(|_| ViewA { id: 3, child: None });
5524                view_2.update(cx, |view, cx| {
5525                    view.child = Some(child.clone().into_any());
5526                    cx.notify();
5527                });
5528                child
5529            })
5530            .unwrap();
5531        let view_4 = cx
5532            .update_window(window_id, |cx| {
5533                let child = cx.add_view(|_| ViewB { id: 4, child: None });
5534                view_3.update(cx, |view, cx| {
5535                    view.child = Some(child.clone().into_any());
5536                    cx.notify();
5537                });
5538                child
5539            })
5540            .unwrap();
5541
5542        cx.update_window(window_id, |cx| {
5543            cx.dispatch_action(Some(view_4.id()), &Action("bar".to_string()))
5544        });
5545
5546        assert_eq!(
5547            *actions.borrow(),
5548            vec![
5549                "1 capture",
5550                "3 capture",
5551                "4 d",
5552                "4 c",
5553                "3 b",
5554                "3 a",
5555                "2 d",
5556                "2 c",
5557                "1 b"
5558            ]
5559        );
5560        assert_eq!(*observed_actions.borrow(), [Action::default().id()]);
5561
5562        // Remove view_1, which doesn't propagate the action
5563
5564        let (window_id, view_2) =
5565            cx.add_window(Default::default(), |_| ViewB { id: 2, child: None });
5566        let view_3 = cx
5567            .update_window(window_id, |cx| {
5568                let child = cx.add_view(|_| ViewA { id: 3, child: None });
5569                view_2.update(cx, |view, cx| {
5570                    view.child = Some(child.clone().into_any());
5571                    cx.notify();
5572                });
5573                child
5574            })
5575            .unwrap();
5576        let view_4 = cx
5577            .update_window(window_id, |cx| {
5578                let child = cx.add_view(|_| ViewB { id: 4, child: None });
5579                view_3.update(cx, |view, cx| {
5580                    view.child = Some(child.clone().into_any());
5581                    cx.notify();
5582                });
5583                child
5584            })
5585            .unwrap();
5586
5587        actions.borrow_mut().clear();
5588        cx.update_window(window_id, |cx| {
5589            cx.dispatch_action(Some(view_4.id()), &Action("bar".to_string()))
5590        });
5591
5592        assert_eq!(
5593            *actions.borrow(),
5594            vec![
5595                "3 capture",
5596                "4 d",
5597                "4 c",
5598                "3 b",
5599                "3 a",
5600                "2 d",
5601                "2 c",
5602                "global"
5603            ]
5604        );
5605        assert_eq!(
5606            *observed_actions.borrow(),
5607            [Action::default().id(), Action::default().id()]
5608        );
5609    }
5610
5611    #[crate::test(self)]
5612    fn test_dispatch_keystroke(cx: &mut AppContext) {
5613        #[derive(Clone, Deserialize, PartialEq)]
5614        pub struct Action(String);
5615
5616        impl_actions!(test, [Action]);
5617
5618        struct View {
5619            id: usize,
5620            keymap_context: KeymapContext,
5621            child: Option<AnyViewHandle>,
5622        }
5623
5624        impl Entity for View {
5625            type Event = ();
5626        }
5627
5628        impl super::View for View {
5629            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5630                self.child
5631                    .as_ref()
5632                    .map(|child| ChildView::new(child, cx).into_any())
5633                    .unwrap_or(Empty::new().into_any())
5634            }
5635
5636            fn ui_name() -> &'static str {
5637                "View"
5638            }
5639
5640            fn keymap_context(&self, _: &AppContext) -> KeymapContext {
5641                self.keymap_context.clone()
5642            }
5643        }
5644
5645        impl View {
5646            fn new(id: usize) -> Self {
5647                View {
5648                    id,
5649                    keymap_context: KeymapContext::default(),
5650                    child: None,
5651                }
5652            }
5653        }
5654
5655        let mut view_1 = View::new(1);
5656        let mut view_2 = View::new(2);
5657        let mut view_3 = View::new(3);
5658        view_1.keymap_context.add_identifier("a");
5659        view_2.keymap_context.add_identifier("a");
5660        view_2.keymap_context.add_identifier("b");
5661        view_3.keymap_context.add_identifier("a");
5662        view_3.keymap_context.add_identifier("b");
5663        view_3.keymap_context.add_identifier("c");
5664
5665        let (window_id, _view_1) = cx.add_window(Default::default(), |cx| {
5666            let view_2 = cx.add_view(|cx| {
5667                let view_3 = cx.add_view(|cx| {
5668                    cx.focus_self();
5669                    view_3
5670                });
5671                view_2.child = Some(view_3.into_any());
5672                view_2
5673            });
5674            view_1.child = Some(view_2.into_any());
5675            view_1
5676        });
5677
5678        // This binding only dispatches an action on view 2 because that view will have
5679        // "a" and "b" in its context, but not "c".
5680        cx.add_bindings(vec![Binding::new(
5681            "a",
5682            Action("a".to_string()),
5683            Some("a && b && !c"),
5684        )]);
5685
5686        cx.add_bindings(vec![Binding::new("b", Action("b".to_string()), None)]);
5687
5688        // This binding only dispatches an action on views 2 and 3, because they have
5689        // a parent view with a in its context
5690        cx.add_bindings(vec![Binding::new(
5691            "c",
5692            Action("c".to_string()),
5693            Some("b > c"),
5694        )]);
5695
5696        // This binding only dispatches an action on view 2, because they have
5697        // a parent view with a in its context
5698        cx.add_bindings(vec![Binding::new(
5699            "d",
5700            Action("d".to_string()),
5701            Some("a && !b > b"),
5702        )]);
5703
5704        let actions = Rc::new(RefCell::new(Vec::new()));
5705        cx.add_action({
5706            let actions = actions.clone();
5707            move |view: &mut View, action: &Action, cx| {
5708                actions
5709                    .borrow_mut()
5710                    .push(format!("{} {}", view.id, action.0));
5711
5712                if action.0 == "b" {
5713                    cx.propagate_action();
5714                }
5715            }
5716        });
5717
5718        cx.add_global_action({
5719            let actions = actions.clone();
5720            move |action: &Action, _| {
5721                actions.borrow_mut().push(format!("global {}", action.0));
5722            }
5723        });
5724
5725        cx.update_window(window_id, |cx| {
5726            cx.dispatch_keystroke(&Keystroke::parse("a").unwrap())
5727        });
5728        assert_eq!(&*actions.borrow(), &["2 a"]);
5729        actions.borrow_mut().clear();
5730
5731        cx.update_window(window_id, |cx| {
5732            cx.dispatch_keystroke(&Keystroke::parse("b").unwrap());
5733        });
5734
5735        assert_eq!(&*actions.borrow(), &["3 b", "2 b", "1 b", "global b"]);
5736        actions.borrow_mut().clear();
5737
5738        cx.update_window(window_id, |cx| {
5739            cx.dispatch_keystroke(&Keystroke::parse("c").unwrap());
5740        });
5741        assert_eq!(&*actions.borrow(), &["3 c"]);
5742        actions.borrow_mut().clear();
5743
5744        cx.update_window(window_id, |cx| {
5745            cx.dispatch_keystroke(&Keystroke::parse("d").unwrap());
5746        });
5747        assert_eq!(&*actions.borrow(), &["2 d"]);
5748        actions.borrow_mut().clear();
5749    }
5750
5751    #[crate::test(self)]
5752    fn test_keystrokes_for_action(cx: &mut AppContext) {
5753        actions!(test, [Action1, Action2, GlobalAction]);
5754
5755        struct View1 {
5756            child: ViewHandle<View2>,
5757        }
5758        struct View2 {}
5759
5760        impl Entity for View1 {
5761            type Event = ();
5762        }
5763        impl Entity for View2 {
5764            type Event = ();
5765        }
5766
5767        impl super::View for View1 {
5768            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5769                ChildView::new(&self.child, cx).into_any()
5770            }
5771            fn ui_name() -> &'static str {
5772                "View1"
5773            }
5774        }
5775        impl super::View for View2 {
5776            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
5777                Empty::new().into_any()
5778            }
5779            fn ui_name() -> &'static str {
5780                "View2"
5781            }
5782        }
5783
5784        let (window_id, view_1) = cx.add_window(Default::default(), |cx| {
5785            let view_2 = cx.add_view(|cx| {
5786                cx.focus_self();
5787                View2 {}
5788            });
5789            View1 { child: view_2 }
5790        });
5791        let view_2 = view_1.read(cx).child.clone();
5792
5793        cx.add_action(|_: &mut View1, _: &Action1, _cx| {});
5794        cx.add_action(|_: &mut View2, _: &Action2, _cx| {});
5795        cx.add_global_action(|_: &GlobalAction, _| {});
5796
5797        cx.add_bindings(vec![
5798            Binding::new("a", Action1, Some("View1")),
5799            Binding::new("b", Action2, Some("View1 > View2")),
5800            Binding::new("c", GlobalAction, Some("View3")), // View 3 does not exist
5801        ]);
5802
5803        cx.update_window(window_id, |cx| {
5804            // Sanity check
5805            assert_eq!(
5806                cx.keystrokes_for_action(view_1.id(), &Action1)
5807                    .unwrap()
5808                    .as_slice(),
5809                &[Keystroke::parse("a").unwrap()]
5810            );
5811            assert_eq!(
5812                cx.keystrokes_for_action(view_2.id(), &Action2)
5813                    .unwrap()
5814                    .as_slice(),
5815                &[Keystroke::parse("b").unwrap()]
5816            );
5817
5818            // The 'a' keystroke propagates up the view tree from view_2
5819            // to view_1. The action, Action1, is handled by view_1.
5820            assert_eq!(
5821                cx.keystrokes_for_action(view_2.id(), &Action1)
5822                    .unwrap()
5823                    .as_slice(),
5824                &[Keystroke::parse("a").unwrap()]
5825            );
5826
5827            // Actions that are handled below the current view don't have bindings
5828            assert_eq!(cx.keystrokes_for_action(view_1.id(), &Action2), None);
5829
5830            // Actions that are handled in other branches of the tree should not have a binding
5831            assert_eq!(cx.keystrokes_for_action(view_2.id(), &GlobalAction), None);
5832
5833            // Check that global actions do not have a binding, even if a binding does exist in another view
5834            assert_eq!(
5835                &available_actions(view_1.id(), cx),
5836                &[
5837                    ("test::Action1", vec![Keystroke::parse("a").unwrap()]),
5838                    ("test::GlobalAction", vec![])
5839                ],
5840            );
5841
5842            // Check that view 1 actions and bindings are available even when called from view 2
5843            assert_eq!(
5844                &available_actions(view_2.id(), cx),
5845                &[
5846                    ("test::Action1", vec![Keystroke::parse("a").unwrap()]),
5847                    ("test::Action2", vec![Keystroke::parse("b").unwrap()]),
5848                    ("test::GlobalAction", vec![]),
5849                ],
5850            );
5851        });
5852
5853        // Produces a list of actions and key bindings
5854        fn available_actions(
5855            view_id: usize,
5856            cx: &WindowContext,
5857        ) -> Vec<(&'static str, Vec<Keystroke>)> {
5858            cx.available_actions(view_id)
5859                .map(|(action_name, _, bindings)| {
5860                    (
5861                        action_name,
5862                        bindings
5863                            .iter()
5864                            .map(|binding| binding.keystrokes()[0].clone())
5865                            .collect::<Vec<_>>(),
5866                    )
5867                })
5868                .sorted_by(|(name1, _), (name2, _)| name1.cmp(name2))
5869                .collect()
5870        }
5871    }
5872
5873    #[crate::test(self)]
5874    async fn test_model_condition(cx: &mut TestAppContext) {
5875        struct Counter(usize);
5876
5877        impl super::Entity for Counter {
5878            type Event = ();
5879        }
5880
5881        impl Counter {
5882            fn inc(&mut self, cx: &mut ModelContext<Self>) {
5883                self.0 += 1;
5884                cx.notify();
5885            }
5886        }
5887
5888        let model = cx.add_model(|_| Counter(0));
5889
5890        let condition1 = model.condition(cx, |model, _| model.0 == 2);
5891        let condition2 = model.condition(cx, |model, _| model.0 == 3);
5892        smol::pin!(condition1, condition2);
5893
5894        model.update(cx, |model, cx| model.inc(cx));
5895        assert_eq!(poll_once(&mut condition1).await, None);
5896        assert_eq!(poll_once(&mut condition2).await, None);
5897
5898        model.update(cx, |model, cx| model.inc(cx));
5899        assert_eq!(poll_once(&mut condition1).await, Some(()));
5900        assert_eq!(poll_once(&mut condition2).await, None);
5901
5902        model.update(cx, |model, cx| model.inc(cx));
5903        assert_eq!(poll_once(&mut condition2).await, Some(()));
5904
5905        model.update(cx, |_, cx| cx.notify());
5906    }
5907
5908    #[crate::test(self)]
5909    #[should_panic]
5910    async fn test_model_condition_timeout(cx: &mut TestAppContext) {
5911        struct Model;
5912
5913        impl super::Entity for Model {
5914            type Event = ();
5915        }
5916
5917        let model = cx.add_model(|_| Model);
5918        model.condition(cx, |_, _| false).await;
5919    }
5920
5921    #[crate::test(self)]
5922    #[should_panic(expected = "model dropped with pending condition")]
5923    async fn test_model_condition_panic_on_drop(cx: &mut TestAppContext) {
5924        struct Model;
5925
5926        impl super::Entity for Model {
5927            type Event = ();
5928        }
5929
5930        let model = cx.add_model(|_| Model);
5931        let condition = model.condition(cx, |_, _| false);
5932        cx.update(|_| drop(model));
5933        condition.await;
5934    }
5935
5936    #[crate::test(self)]
5937    async fn test_view_condition(cx: &mut TestAppContext) {
5938        struct Counter(usize);
5939
5940        impl super::Entity for Counter {
5941            type Event = ();
5942        }
5943
5944        impl super::View for Counter {
5945            fn ui_name() -> &'static str {
5946                "test view"
5947            }
5948
5949            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
5950                Empty::new().into_any()
5951            }
5952        }
5953
5954        impl Counter {
5955            fn inc(&mut self, cx: &mut ViewContext<Self>) {
5956                self.0 += 1;
5957                cx.notify();
5958            }
5959        }
5960
5961        let (_, view) = cx.add_window(|_| Counter(0));
5962
5963        let condition1 = view.condition(cx, |view, _| view.0 == 2);
5964        let condition2 = view.condition(cx, |view, _| view.0 == 3);
5965        smol::pin!(condition1, condition2);
5966
5967        view.update(cx, |view, cx| view.inc(cx));
5968        assert_eq!(poll_once(&mut condition1).await, None);
5969        assert_eq!(poll_once(&mut condition2).await, None);
5970
5971        view.update(cx, |view, cx| view.inc(cx));
5972        assert_eq!(poll_once(&mut condition1).await, Some(()));
5973        assert_eq!(poll_once(&mut condition2).await, None);
5974
5975        view.update(cx, |view, cx| view.inc(cx));
5976        assert_eq!(poll_once(&mut condition2).await, Some(()));
5977        view.update(cx, |_, cx| cx.notify());
5978    }
5979
5980    #[crate::test(self)]
5981    #[should_panic]
5982    async fn test_view_condition_timeout(cx: &mut TestAppContext) {
5983        let (_, view) = cx.add_window(|_| TestView::default());
5984        view.condition(cx, |_, _| false).await;
5985    }
5986
5987    #[crate::test(self)]
5988    #[should_panic(expected = "view dropped with pending condition")]
5989    async fn test_view_condition_panic_on_drop(cx: &mut TestAppContext) {
5990        let (window_id, _root_view) = cx.add_window(|_| TestView::default());
5991        let view = cx.add_view(window_id, |_| TestView::default());
5992
5993        let condition = view.condition(cx, |_, _| false);
5994        cx.update(|_| drop(view));
5995        condition.await;
5996    }
5997
5998    #[crate::test(self)]
5999    fn test_refresh_windows(cx: &mut AppContext) {
6000        struct View(usize);
6001
6002        impl super::Entity for View {
6003            type Event = ();
6004        }
6005
6006        impl super::View for View {
6007            fn ui_name() -> &'static str {
6008                "test view"
6009            }
6010
6011            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6012                Empty::new().into_any_named(format!("render count: {}", post_inc(&mut self.0)))
6013            }
6014        }
6015
6016        let (window_id, root_view) = cx.add_window(Default::default(), |_| View(0));
6017        cx.update_window(window_id, |cx| {
6018            assert_eq!(
6019                cx.window.rendered_views[&root_view.id()].name(),
6020                Some("render count: 0")
6021            );
6022        });
6023
6024        let view = cx
6025            .update_window(window_id, |cx| {
6026                cx.refresh_windows();
6027                cx.add_view(|_| View(0))
6028            })
6029            .unwrap();
6030
6031        cx.update_window(window_id, |cx| {
6032            assert_eq!(
6033                cx.window.rendered_views[&root_view.id()].name(),
6034                Some("render count: 1")
6035            );
6036            assert_eq!(
6037                cx.window.rendered_views[&view.id()].name(),
6038                Some("render count: 0")
6039            );
6040        });
6041
6042        cx.update(|cx| cx.refresh_windows());
6043
6044        cx.update_window(window_id, |cx| {
6045            assert_eq!(
6046                cx.window.rendered_views[&root_view.id()].name(),
6047                Some("render count: 2")
6048            );
6049            assert_eq!(
6050                cx.window.rendered_views[&view.id()].name(),
6051                Some("render count: 1")
6052            );
6053        });
6054
6055        cx.update(|cx| {
6056            cx.refresh_windows();
6057            drop(view);
6058        });
6059
6060        cx.update_window(window_id, |cx| {
6061            assert_eq!(
6062                cx.window.rendered_views[&root_view.id()].name(),
6063                Some("render count: 3")
6064            );
6065            assert_eq!(cx.window.rendered_views.len(), 1);
6066        });
6067    }
6068
6069    #[crate::test(self)]
6070    async fn test_labeled_tasks(cx: &mut TestAppContext) {
6071        assert_eq!(None, cx.update(|cx| cx.active_labeled_tasks().next()));
6072        let (mut sender, mut reciever) = postage::oneshot::channel::<()>();
6073        let task = cx
6074            .update(|cx| cx.spawn_labeled("Test Label", |_| async move { reciever.recv().await }));
6075
6076        assert_eq!(
6077            Some("Test Label"),
6078            cx.update(|cx| cx.active_labeled_tasks().next())
6079        );
6080        sender
6081            .send(())
6082            .await
6083            .expect("Could not send message to complete task");
6084        task.await;
6085
6086        assert_eq!(None, cx.update(|cx| cx.active_labeled_tasks().next()));
6087    }
6088
6089    #[crate::test(self)]
6090    async fn test_window_activation(cx: &mut TestAppContext) {
6091        struct View(&'static str);
6092
6093        impl super::Entity for View {
6094            type Event = ();
6095        }
6096
6097        impl super::View for View {
6098            fn ui_name() -> &'static str {
6099                "test view"
6100            }
6101
6102            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6103                Empty::new().into_any()
6104            }
6105        }
6106
6107        let events = Rc::new(RefCell::new(Vec::new()));
6108        let (window_1, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6109            cx.observe_window_activation({
6110                let events = events.clone();
6111                move |this, active, _| events.borrow_mut().push((this.0, active))
6112            })
6113            .detach();
6114            View("window 1")
6115        });
6116        assert_eq!(mem::take(&mut *events.borrow_mut()), [("window 1", true)]);
6117
6118        let (window_2, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6119            cx.observe_window_activation({
6120                let events = events.clone();
6121                move |this, active, _| events.borrow_mut().push((this.0, active))
6122            })
6123            .detach();
6124            View("window 2")
6125        });
6126        assert_eq!(
6127            mem::take(&mut *events.borrow_mut()),
6128            [("window 1", false), ("window 2", true)]
6129        );
6130
6131        let (window_3, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6132            cx.observe_window_activation({
6133                let events = events.clone();
6134                move |this, active, _| events.borrow_mut().push((this.0, active))
6135            })
6136            .detach();
6137            View("window 3")
6138        });
6139        assert_eq!(
6140            mem::take(&mut *events.borrow_mut()),
6141            [("window 2", false), ("window 3", true)]
6142        );
6143
6144        cx.simulate_window_activation(Some(window_2));
6145        assert_eq!(
6146            mem::take(&mut *events.borrow_mut()),
6147            [("window 3", false), ("window 2", true)]
6148        );
6149
6150        cx.simulate_window_activation(Some(window_1));
6151        assert_eq!(
6152            mem::take(&mut *events.borrow_mut()),
6153            [("window 2", false), ("window 1", true)]
6154        );
6155
6156        cx.simulate_window_activation(Some(window_3));
6157        assert_eq!(
6158            mem::take(&mut *events.borrow_mut()),
6159            [("window 1", false), ("window 3", true)]
6160        );
6161
6162        cx.simulate_window_activation(Some(window_3));
6163        assert_eq!(mem::take(&mut *events.borrow_mut()), []);
6164    }
6165
6166    #[crate::test(self)]
6167    fn test_child_view(cx: &mut TestAppContext) {
6168        struct Child {
6169            rendered: Rc<Cell<bool>>,
6170            dropped: Rc<Cell<bool>>,
6171        }
6172
6173        impl super::Entity for Child {
6174            type Event = ();
6175        }
6176
6177        impl super::View for Child {
6178            fn ui_name() -> &'static str {
6179                "child view"
6180            }
6181
6182            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6183                self.rendered.set(true);
6184                Empty::new().into_any()
6185            }
6186        }
6187
6188        impl Drop for Child {
6189            fn drop(&mut self) {
6190                self.dropped.set(true);
6191            }
6192        }
6193
6194        struct Parent {
6195            child: Option<ViewHandle<Child>>,
6196        }
6197
6198        impl super::Entity for Parent {
6199            type Event = ();
6200        }
6201
6202        impl super::View for Parent {
6203            fn ui_name() -> &'static str {
6204                "parent view"
6205            }
6206
6207            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
6208                if let Some(child) = self.child.as_ref() {
6209                    ChildView::new(child, cx).into_any()
6210                } else {
6211                    Empty::new().into_any()
6212                }
6213            }
6214        }
6215
6216        let child_rendered = Rc::new(Cell::new(false));
6217        let child_dropped = Rc::new(Cell::new(false));
6218        let (_, root_view) = cx.add_window(|cx| Parent {
6219            child: Some(cx.add_view(|_| Child {
6220                rendered: child_rendered.clone(),
6221                dropped: child_dropped.clone(),
6222            })),
6223        });
6224        assert!(child_rendered.take());
6225        assert!(!child_dropped.take());
6226
6227        root_view.update(cx, |view, cx| {
6228            view.child.take();
6229            cx.notify();
6230        });
6231        assert!(!child_rendered.take());
6232        assert!(child_dropped.take());
6233    }
6234
6235    #[derive(Default)]
6236    struct TestView {
6237        events: Vec<String>,
6238    }
6239
6240    impl Entity for TestView {
6241        type Event = String;
6242    }
6243
6244    impl View for TestView {
6245        fn ui_name() -> &'static str {
6246            "TestView"
6247        }
6248
6249        fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6250            Empty::new().into_any()
6251        }
6252    }
6253}