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