app.rs

   1pub mod action;
   2mod callback_collection;
   3mod menu;
   4pub(crate) mod ref_counts;
   5#[cfg(any(test, feature = "test-support"))]
   6pub mod test_app_context;
   7pub(crate) mod window;
   8mod window_input_handler;
   9
  10use std::{
  11    any::{type_name, Any, TypeId},
  12    cell::RefCell,
  13    fmt::{self, Debug},
  14    hash::{Hash, Hasher},
  15    marker::PhantomData,
  16    mem,
  17    ops::{Deref, DerefMut, Range},
  18    path::{Path, PathBuf},
  19    pin::Pin,
  20    rc::{self, Rc},
  21    sync::{Arc, Weak},
  22    time::Duration,
  23};
  24
  25use anyhow::{anyhow, Context, Result};
  26use parking_lot::Mutex;
  27use postage::oneshot;
  28use smol::prelude::*;
  29use util::ResultExt;
  30use uuid::Uuid;
  31
  32pub use action::*;
  33use callback_collection::CallbackCollection;
  34use collections::{hash_map::Entry, BTreeMap, HashMap, HashSet, VecDeque};
  35pub use menu::*;
  36use platform::Event;
  37#[cfg(any(test, feature = "test-support"))]
  38use ref_counts::LeakDetector;
  39#[cfg(any(test, feature = "test-support"))]
  40pub use test_app_context::{ContextHandle, TestAppContext};
  41use window_input_handler::WindowInputHandler;
  42
  43use crate::{
  44    elements::{AnyElement, AnyRootElement, RootElement},
  45    executor::{self, Task},
  46    json,
  47    keymap_matcher::{self, Binding, KeymapContext, KeymapMatcher, Keystroke, MatchResult},
  48    platform::{
  49        self, FontSystem, KeyDownEvent, KeyUpEvent, ModifiersChangedEvent, MouseButton,
  50        PathPromptOptions, Platform, PromptLevel, WindowBounds, WindowOptions,
  51    },
  52    util::post_inc,
  53    window::{Window, WindowContext},
  54    AssetCache, AssetSource, ClipboardItem, FontCache, MouseRegionId,
  55};
  56
  57use self::ref_counts::RefCounts;
  58
  59pub trait Entity: 'static {
  60    type Event;
  61
  62    fn release(&mut self, _: &mut AppContext) {}
  63    fn app_will_quit(
  64        &mut self,
  65        _: &mut AppContext,
  66    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
  67        None
  68    }
  69}
  70
  71pub trait View: Entity + Sized {
  72    fn ui_name() -> &'static str;
  73    fn render(&mut self, cx: &mut ViewContext<'_, '_, Self>) -> AnyElement<Self>;
  74    fn focus_in(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  75    fn focus_out(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  76    fn key_down(&mut self, _: &KeyDownEvent, _: &mut ViewContext<Self>) -> bool {
  77        false
  78    }
  79    fn key_up(&mut self, _: &KeyUpEvent, _: &mut ViewContext<Self>) -> bool {
  80        false
  81    }
  82    fn modifiers_changed(&mut self, _: &ModifiersChangedEvent, _: &mut ViewContext<Self>) -> bool {
  83        false
  84    }
  85
  86    fn keymap_context(&self, _: &AppContext) -> keymap_matcher::KeymapContext {
  87        Self::default_keymap_context()
  88    }
  89    fn default_keymap_context() -> keymap_matcher::KeymapContext {
  90        let mut cx = keymap_matcher::KeymapContext::default();
  91        cx.add_identifier(Self::ui_name());
  92        cx
  93    }
  94    fn debug_json(&self, _: &AppContext) -> serde_json::Value {
  95        serde_json::Value::Null
  96    }
  97
  98    fn text_for_range(&self, _: Range<usize>, _: &AppContext) -> Option<String> {
  99        None
 100    }
 101    fn selected_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
 102        None
 103    }
 104    fn marked_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
 105        None
 106    }
 107    fn unmark_text(&mut self, _: &mut ViewContext<Self>) {}
 108    fn replace_text_in_range(
 109        &mut self,
 110        _: Option<Range<usize>>,
 111        _: &str,
 112        _: &mut ViewContext<Self>,
 113    ) {
 114    }
 115    fn replace_and_mark_text_in_range(
 116        &mut self,
 117        _: Option<Range<usize>>,
 118        _: &str,
 119        _: Option<Range<usize>>,
 120        _: &mut ViewContext<Self>,
 121    ) {
 122    }
 123}
 124
 125pub trait BorrowAppContext {
 126    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T;
 127    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T;
 128}
 129
 130pub trait BorrowWindowContext {
 131    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T;
 132    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T;
 133}
 134
 135#[derive(Clone)]
 136pub struct App(Rc<RefCell<AppContext>>);
 137
 138impl App {
 139    pub fn new(asset_source: impl AssetSource) -> Result<Self> {
 140        let platform = platform::current::platform();
 141        let foreground = Rc::new(executor::Foreground::platform(platform.dispatcher())?);
 142        let foreground_platform = platform::current::foreground_platform(foreground.clone());
 143        let app = Self(Rc::new(RefCell::new(AppContext::new(
 144            foreground,
 145            Arc::new(executor::Background::new()),
 146            platform.clone(),
 147            foreground_platform.clone(),
 148            Arc::new(FontCache::new(platform.fonts())),
 149            Default::default(),
 150            asset_source,
 151        ))));
 152
 153        foreground_platform.on_quit(Box::new({
 154            let cx = app.0.clone();
 155            move || {
 156                cx.borrow_mut().quit();
 157            }
 158        }));
 159        setup_menu_handlers(foreground_platform.as_ref(), &app);
 160
 161        app.0.borrow_mut().weak_self = Some(Rc::downgrade(&app.0));
 162        Ok(app)
 163    }
 164
 165    pub fn background(&self) -> Arc<executor::Background> {
 166        self.0.borrow().background().clone()
 167    }
 168
 169    pub fn on_become_active<F>(self, mut callback: F) -> Self
 170    where
 171        F: 'static + FnMut(&mut AppContext),
 172    {
 173        let cx = self.0.clone();
 174        self.0
 175            .borrow_mut()
 176            .foreground_platform
 177            .on_become_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 178        self
 179    }
 180
 181    pub fn on_resign_active<F>(self, mut callback: F) -> Self
 182    where
 183        F: 'static + FnMut(&mut AppContext),
 184    {
 185        let cx = self.0.clone();
 186        self.0
 187            .borrow_mut()
 188            .foreground_platform
 189            .on_resign_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 190        self
 191    }
 192
 193    pub fn on_quit<F>(&mut self, mut callback: F) -> &mut Self
 194    where
 195        F: 'static + FnMut(&mut AppContext),
 196    {
 197        let cx = self.0.clone();
 198        self.0
 199            .borrow_mut()
 200            .foreground_platform
 201            .on_quit(Box::new(move || callback(&mut *cx.borrow_mut())));
 202        self
 203    }
 204
 205    /// Handle the application being re-activated when no windows are open.
 206    pub fn on_reopen<F>(&mut self, mut callback: F) -> &mut Self
 207    where
 208        F: 'static + FnMut(&mut AppContext),
 209    {
 210        let cx = self.0.clone();
 211        self.0
 212            .borrow_mut()
 213            .foreground_platform
 214            .on_reopen(Box::new(move || callback(&mut *cx.borrow_mut())));
 215        self
 216    }
 217
 218    pub fn on_event<F>(&mut self, mut callback: F) -> &mut Self
 219    where
 220        F: 'static + FnMut(Event, &mut AppContext) -> bool,
 221    {
 222        let cx = self.0.clone();
 223        self.0
 224            .borrow_mut()
 225            .foreground_platform
 226            .on_event(Box::new(move |event| {
 227                callback(event, &mut *cx.borrow_mut())
 228            }));
 229        self
 230    }
 231
 232    pub fn on_open_urls<F>(&mut self, mut callback: F) -> &mut Self
 233    where
 234        F: 'static + FnMut(Vec<String>, &mut AppContext),
 235    {
 236        let cx = self.0.clone();
 237        self.0
 238            .borrow_mut()
 239            .foreground_platform
 240            .on_open_urls(Box::new(move |urls| callback(urls, &mut *cx.borrow_mut())));
 241        self
 242    }
 243
 244    pub fn run<F>(self, on_finish_launching: F)
 245    where
 246        F: 'static + FnOnce(&mut AppContext),
 247    {
 248        let platform = self.0.borrow().foreground_platform.clone();
 249        platform.run(Box::new(move || {
 250            let mut cx = self.0.borrow_mut();
 251            let cx = &mut *cx;
 252            crate::views::init(cx);
 253            on_finish_launching(cx);
 254        }))
 255    }
 256
 257    pub fn platform(&self) -> Arc<dyn Platform> {
 258        self.0.borrow().platform.clone()
 259    }
 260
 261    pub fn font_cache(&self) -> Arc<FontCache> {
 262        self.0.borrow().font_cache.clone()
 263    }
 264
 265    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, callback: F) -> T {
 266        let mut state = self.0.borrow_mut();
 267        let result = state.update(callback);
 268        state.pending_notifications.clear();
 269        result
 270    }
 271
 272    fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 273        &mut self,
 274        window_id: usize,
 275        callback: F,
 276    ) -> Option<T> {
 277        let mut state = self.0.borrow_mut();
 278        let result = state.update_window(window_id, callback);
 279        state.pending_notifications.clear();
 280        result
 281    }
 282}
 283
 284#[derive(Clone)]
 285pub struct AsyncAppContext(Rc<RefCell<AppContext>>);
 286
 287impl AsyncAppContext {
 288    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
 289    where
 290        F: FnOnce(AsyncAppContext) -> Fut,
 291        Fut: 'static + Future<Output = T>,
 292        T: 'static,
 293    {
 294        self.0.borrow().foreground.spawn(f(self.clone()))
 295    }
 296
 297    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 298        callback(&*self.0.borrow())
 299    }
 300
 301    pub fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, callback: F) -> T {
 302        self.0.borrow_mut().update(callback)
 303    }
 304
 305    pub fn read_window<T, F: FnOnce(&WindowContext) -> T>(
 306        &self,
 307        window_id: usize,
 308        callback: F,
 309    ) -> Option<T> {
 310        self.0.borrow_mut().read_window(window_id, callback)
 311    }
 312
 313    pub fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 314        &mut self,
 315        window_id: usize,
 316        callback: F,
 317    ) -> Option<T> {
 318        self.0.borrow_mut().update_window(window_id, callback)
 319    }
 320
 321    pub fn debug_elements(&self, window_id: usize) -> Option<json::Value> {
 322        self.0.borrow().read_window(window_id, |cx| {
 323            let root_view = cx.window.root_view();
 324            let root_element = cx.window.rendered_views.get(&root_view.id())?;
 325            root_element.debug(cx).log_err()
 326        })?
 327    }
 328
 329    pub fn dispatch_action(
 330        &mut self,
 331        window_id: usize,
 332        view_id: usize,
 333        action: &dyn Action,
 334    ) -> Result<()> {
 335        self.0
 336            .borrow_mut()
 337            .update_window(window_id, |window| {
 338                window.dispatch_action(Some(view_id), action);
 339            })
 340            .ok_or_else(|| anyhow!("window not found"))
 341    }
 342
 343    pub fn has_window(&self, window_id: usize) -> bool {
 344        self.read(|cx| cx.windows.contains_key(&window_id))
 345    }
 346
 347    pub fn window_is_active(&self, window_id: usize) -> bool {
 348        self.read(|cx| cx.windows.get(&window_id).map_or(false, |w| w.is_active))
 349    }
 350
 351    pub fn root_view(&self, window_id: usize) -> Option<AnyViewHandle> {
 352        self.read(|cx| cx.windows.get(&window_id).map(|w| w.root_view().clone()))
 353    }
 354
 355    pub fn window_ids(&self) -> Vec<usize> {
 356        self.read(|cx| cx.windows.keys().copied().collect())
 357    }
 358
 359    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 360    where
 361        T: Entity,
 362        F: FnOnce(&mut ModelContext<T>) -> T,
 363    {
 364        self.update(|cx| cx.add_model(build_model))
 365    }
 366
 367    pub fn add_window<T, F>(
 368        &mut self,
 369        window_options: WindowOptions,
 370        build_root_view: F,
 371    ) -> (usize, ViewHandle<T>)
 372    where
 373        T: View,
 374        F: FnOnce(&mut ViewContext<T>) -> T,
 375    {
 376        self.update(|cx| cx.add_window(window_options, build_root_view))
 377    }
 378
 379    pub fn remove_window(&mut self, window_id: usize) {
 380        self.update_window(window_id, |cx| cx.remove_window());
 381    }
 382
 383    pub fn activate_window(&mut self, window_id: usize) {
 384        self.update_window(window_id, |cx| cx.activate_window());
 385    }
 386
 387    // TODO: Can we eliminate this method and move it to WindowContext then call it with update_window?s
 388    pub fn prompt(
 389        &mut self,
 390        window_id: usize,
 391        level: PromptLevel,
 392        msg: &str,
 393        answers: &[&str],
 394    ) -> Option<oneshot::Receiver<usize>> {
 395        self.update_window(window_id, |cx| cx.prompt(level, msg, answers))
 396    }
 397
 398    pub fn platform(&self) -> Arc<dyn Platform> {
 399        self.0.borrow().platform().clone()
 400    }
 401
 402    pub fn foreground(&self) -> Rc<executor::Foreground> {
 403        self.0.borrow().foreground.clone()
 404    }
 405
 406    pub fn background(&self) -> Arc<executor::Background> {
 407        self.0.borrow().background.clone()
 408    }
 409}
 410
 411impl BorrowAppContext for AsyncAppContext {
 412    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
 413        self.0.borrow().read_with(f)
 414    }
 415
 416    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
 417        self.0.borrow_mut().update(f)
 418    }
 419}
 420
 421type ActionCallback = dyn FnMut(&mut dyn AnyView, &dyn Action, &mut WindowContext, usize);
 422type GlobalActionCallback = dyn FnMut(&dyn Action, &mut AppContext);
 423
 424type SubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool>;
 425type GlobalSubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut AppContext)>;
 426type ObservationCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 427type GlobalObservationCallback = Box<dyn FnMut(&mut AppContext)>;
 428type FocusObservationCallback = Box<dyn FnMut(bool, &mut WindowContext) -> bool>;
 429type ReleaseObservationCallback = Box<dyn FnMut(&dyn Any, &mut AppContext)>;
 430type ActionObservationCallback = Box<dyn FnMut(TypeId, &mut AppContext)>;
 431type WindowActivationCallback = Box<dyn FnMut(bool, &mut WindowContext) -> bool>;
 432type WindowFullscreenCallback = Box<dyn FnMut(bool, &mut WindowContext) -> bool>;
 433type WindowBoundsCallback = Box<dyn FnMut(WindowBounds, Uuid, &mut WindowContext) -> bool>;
 434type KeystrokeCallback =
 435    Box<dyn FnMut(&Keystroke, &MatchResult, Option<&Box<dyn Action>>, &mut WindowContext) -> bool>;
 436type ActiveLabeledTasksCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 437type DeserializeActionCallback = fn(json: &str) -> anyhow::Result<Box<dyn Action>>;
 438type WindowShouldCloseSubscriptionCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 439
 440pub struct AppContext {
 441    models: HashMap<usize, Box<dyn AnyModel>>,
 442    views: HashMap<(usize, usize), Box<dyn AnyView>>,
 443    windows: HashMap<usize, Window>,
 444    globals: HashMap<TypeId, Box<dyn Any>>,
 445    element_states: HashMap<ElementStateId, Box<dyn Any>>,
 446    background: Arc<executor::Background>,
 447    ref_counts: Arc<Mutex<RefCounts>>,
 448
 449    weak_self: Option<rc::Weak<RefCell<Self>>>,
 450    platform: Arc<dyn Platform>,
 451    foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 452    pub asset_cache: Arc<AssetCache>,
 453    font_system: Arc<dyn FontSystem>,
 454    pub font_cache: Arc<FontCache>,
 455    action_deserializers: HashMap<&'static str, (TypeId, DeserializeActionCallback)>,
 456    capture_actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 457    // Entity Types -> { Action Types -> Action Handlers }
 458    actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 459    // Action Types -> Action Handlers
 460    global_actions: HashMap<TypeId, Box<GlobalActionCallback>>,
 461    keystroke_matcher: KeymapMatcher,
 462    next_entity_id: usize,
 463    next_window_id: usize,
 464    next_subscription_id: usize,
 465    frame_count: usize,
 466
 467    subscriptions: CallbackCollection<usize, SubscriptionCallback>,
 468    global_subscriptions: CallbackCollection<TypeId, GlobalSubscriptionCallback>,
 469    observations: CallbackCollection<usize, ObservationCallback>,
 470    global_observations: CallbackCollection<TypeId, GlobalObservationCallback>,
 471    focus_observations: CallbackCollection<usize, FocusObservationCallback>,
 472    release_observations: CallbackCollection<usize, ReleaseObservationCallback>,
 473    action_dispatch_observations: CallbackCollection<(), ActionObservationCallback>,
 474    window_activation_observations: CallbackCollection<usize, WindowActivationCallback>,
 475    window_fullscreen_observations: CallbackCollection<usize, WindowFullscreenCallback>,
 476    window_bounds_observations: CallbackCollection<usize, WindowBoundsCallback>,
 477    keystroke_observations: CallbackCollection<usize, KeystrokeCallback>,
 478    active_labeled_task_observations: CallbackCollection<(), ActiveLabeledTasksCallback>,
 479
 480    foreground: Rc<executor::Foreground>,
 481    pending_effects: VecDeque<Effect>,
 482    pending_notifications: HashSet<usize>,
 483    pending_global_notifications: HashSet<TypeId>,
 484    pending_flushes: usize,
 485    flushing_effects: bool,
 486    halt_action_dispatch: bool,
 487    next_labeled_task_id: usize,
 488    active_labeled_tasks: BTreeMap<usize, &'static str>,
 489}
 490
 491impl AppContext {
 492    fn new(
 493        foreground: Rc<executor::Foreground>,
 494        background: Arc<executor::Background>,
 495        platform: Arc<dyn platform::Platform>,
 496        foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 497        font_cache: Arc<FontCache>,
 498        ref_counts: RefCounts,
 499        asset_source: impl AssetSource,
 500    ) -> Self {
 501        Self {
 502            models: Default::default(),
 503            views: Default::default(),
 504            windows: Default::default(),
 505            globals: Default::default(),
 506            element_states: Default::default(),
 507            ref_counts: Arc::new(Mutex::new(ref_counts)),
 508            background,
 509
 510            weak_self: None,
 511            font_system: platform.fonts(),
 512            platform,
 513            foreground_platform,
 514            font_cache,
 515            asset_cache: Arc::new(AssetCache::new(asset_source)),
 516            action_deserializers: Default::default(),
 517            capture_actions: Default::default(),
 518            actions: Default::default(),
 519            global_actions: Default::default(),
 520            keystroke_matcher: KeymapMatcher::default(),
 521            next_entity_id: 0,
 522            next_window_id: 0,
 523            next_subscription_id: 0,
 524            frame_count: 0,
 525            subscriptions: Default::default(),
 526            global_subscriptions: Default::default(),
 527            observations: Default::default(),
 528            focus_observations: Default::default(),
 529            release_observations: Default::default(),
 530            global_observations: Default::default(),
 531            window_activation_observations: Default::default(),
 532            window_fullscreen_observations: Default::default(),
 533            window_bounds_observations: Default::default(),
 534            keystroke_observations: Default::default(),
 535            action_dispatch_observations: Default::default(),
 536            active_labeled_task_observations: Default::default(),
 537            foreground,
 538            pending_effects: VecDeque::new(),
 539            pending_notifications: Default::default(),
 540            pending_global_notifications: Default::default(),
 541            pending_flushes: 0,
 542            flushing_effects: false,
 543            halt_action_dispatch: false,
 544            next_labeled_task_id: 0,
 545            active_labeled_tasks: Default::default(),
 546        }
 547    }
 548
 549    pub fn background(&self) -> &Arc<executor::Background> {
 550        &self.background
 551    }
 552
 553    pub fn font_cache(&self) -> &Arc<FontCache> {
 554        &self.font_cache
 555    }
 556
 557    pub fn platform(&self) -> &Arc<dyn Platform> {
 558        &self.platform
 559    }
 560
 561    pub fn has_global<T: 'static>(&self) -> bool {
 562        self.globals.contains_key(&TypeId::of::<T>())
 563    }
 564
 565    pub fn global<T: 'static>(&self) -> &T {
 566        if let Some(global) = self.globals.get(&TypeId::of::<T>()) {
 567            global.downcast_ref().unwrap()
 568        } else {
 569            panic!("no global has been added for {}", type_name::<T>());
 570        }
 571    }
 572
 573    pub fn upgrade(&self) -> App {
 574        App(self.weak_self.as_ref().unwrap().upgrade().unwrap())
 575    }
 576
 577    fn quit(&mut self) {
 578        let mut futures = Vec::new();
 579
 580        self.update(|cx| {
 581            for model_id in cx.models.keys().copied().collect::<Vec<_>>() {
 582                let mut model = cx.models.remove(&model_id).unwrap();
 583                futures.extend(model.app_will_quit(cx));
 584                cx.models.insert(model_id, model);
 585            }
 586
 587            for view_id in cx.views.keys().copied().collect::<Vec<_>>() {
 588                let mut view = cx.views.remove(&view_id).unwrap();
 589                futures.extend(view.app_will_quit(cx));
 590                cx.views.insert(view_id, view);
 591            }
 592        });
 593
 594        self.windows.clear();
 595        self.flush_effects();
 596
 597        let futures = futures::future::join_all(futures);
 598        if self
 599            .background
 600            .block_with_timeout(Duration::from_millis(100), futures)
 601            .is_err()
 602        {
 603            log::error!("timed out waiting on app_will_quit");
 604        }
 605    }
 606
 607    pub fn foreground(&self) -> &Rc<executor::Foreground> {
 608        &self.foreground
 609    }
 610
 611    pub fn deserialize_action(
 612        &self,
 613        name: &str,
 614        argument: Option<&str>,
 615    ) -> Result<Box<dyn Action>> {
 616        let callback = self
 617            .action_deserializers
 618            .get(name)
 619            .ok_or_else(|| anyhow!("unknown action {}", name))?
 620            .1;
 621        callback(argument.unwrap_or("{}"))
 622            .with_context(|| format!("invalid data for action {}", name))
 623    }
 624
 625    pub fn add_action<A, V, F, R>(&mut self, handler: F)
 626    where
 627        A: Action,
 628        V: View,
 629        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> R,
 630    {
 631        self.add_action_internal(handler, false)
 632    }
 633
 634    pub fn capture_action<A, V, F>(&mut self, handler: F)
 635    where
 636        A: Action,
 637        V: View,
 638        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
 639    {
 640        self.add_action_internal(handler, true)
 641    }
 642
 643    fn add_action_internal<A, V, F, R>(&mut self, mut handler: F, capture: bool)
 644    where
 645        A: Action,
 646        V: View,
 647        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> R,
 648    {
 649        let handler = Box::new(
 650            move |view: &mut dyn AnyView,
 651                  action: &dyn Action,
 652                  cx: &mut WindowContext,
 653                  view_id: usize| {
 654                let action = action.as_any().downcast_ref().unwrap();
 655                let mut cx = ViewContext::mutable(cx, view_id);
 656                handler(
 657                    view.as_any_mut()
 658                        .downcast_mut()
 659                        .expect("downcast is type safe"),
 660                    action,
 661                    &mut cx,
 662                );
 663            },
 664        );
 665
 666        self.action_deserializers
 667            .entry(A::qualified_name())
 668            .or_insert((TypeId::of::<A>(), A::from_json_str));
 669
 670        let actions = if capture {
 671            &mut self.capture_actions
 672        } else {
 673            &mut self.actions
 674        };
 675
 676        actions
 677            .entry(TypeId::of::<V>())
 678            .or_default()
 679            .entry(TypeId::of::<A>())
 680            .or_default()
 681            .push(handler);
 682    }
 683
 684    pub fn add_async_action<A, V, F>(&mut self, mut handler: F)
 685    where
 686        A: Action,
 687        V: View,
 688        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> Option<Task<Result<()>>>,
 689    {
 690        self.add_action(move |view, action, cx| {
 691            if let Some(task) = handler(view, action, cx) {
 692                task.detach_and_log_err(cx);
 693            }
 694        })
 695    }
 696
 697    pub fn add_global_action<A, F>(&mut self, mut handler: F)
 698    where
 699        A: Action,
 700        F: 'static + FnMut(&A, &mut AppContext),
 701    {
 702        let handler = Box::new(move |action: &dyn Action, cx: &mut AppContext| {
 703            let action = action.as_any().downcast_ref().unwrap();
 704            handler(action, cx);
 705        });
 706
 707        self.action_deserializers
 708            .entry(A::qualified_name())
 709            .or_insert((TypeId::of::<A>(), A::from_json_str));
 710
 711        if self
 712            .global_actions
 713            .insert(TypeId::of::<A>(), handler)
 714            .is_some()
 715        {
 716            panic!(
 717                "registered multiple global handlers for {}",
 718                type_name::<A>()
 719            );
 720        }
 721    }
 722
 723    pub fn view_ui_name(&self, window_id: usize, view_id: usize) -> Option<&'static str> {
 724        Some(self.views.get(&(window_id, view_id))?.ui_name())
 725    }
 726
 727    pub fn view_type_id(&self, window_id: usize, view_id: usize) -> Option<TypeId> {
 728        self.views
 729            .get(&(window_id, view_id))
 730            .map(|view| view.as_any().type_id())
 731    }
 732
 733    pub fn active_labeled_tasks<'a>(
 734        &'a self,
 735    ) -> impl DoubleEndedIterator<Item = &'static str> + 'a {
 736        self.active_labeled_tasks.values().cloned()
 737    }
 738
 739    pub(crate) fn start_frame(&mut self) {
 740        self.frame_count += 1;
 741    }
 742
 743    pub fn update<T, F: FnOnce(&mut Self) -> T>(&mut self, callback: F) -> T {
 744        self.pending_flushes += 1;
 745        let result = callback(self);
 746        self.flush_effects();
 747        result
 748    }
 749
 750    pub fn read_window<T, F: FnOnce(&WindowContext) -> T>(
 751        &self,
 752        window_id: usize,
 753        callback: F,
 754    ) -> Option<T> {
 755        let window = self.windows.get(&window_id)?;
 756        let window_context = WindowContext::immutable(self, &window, window_id);
 757        Some(callback(&window_context))
 758    }
 759
 760    pub fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 761        &mut self,
 762        window_id: usize,
 763        callback: F,
 764    ) -> Option<T> {
 765        self.update(|app_context| {
 766            let mut window = app_context.windows.remove(&window_id)?;
 767            let mut window_context = WindowContext::mutable(app_context, &mut window, window_id);
 768            let result = callback(&mut window_context);
 769            if !window_context.removed {
 770                app_context.windows.insert(window_id, window);
 771            }
 772            Some(result)
 773        })
 774    }
 775
 776    pub fn update_active_window<T, F: FnOnce(&mut WindowContext) -> T>(
 777        &mut self,
 778        callback: F,
 779    ) -> Option<T> {
 780        self.platform
 781            .main_window_id()
 782            .and_then(|id| self.update_window(id, callback))
 783    }
 784
 785    pub fn prompt_for_paths(
 786        &self,
 787        options: PathPromptOptions,
 788    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
 789        self.foreground_platform.prompt_for_paths(options)
 790    }
 791
 792    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
 793        self.foreground_platform.prompt_for_new_path(directory)
 794    }
 795
 796    pub fn reveal_path(&self, path: &Path) {
 797        self.foreground_platform.reveal_path(path)
 798    }
 799
 800    pub fn emit_global<E: Any>(&mut self, payload: E) {
 801        self.pending_effects.push_back(Effect::GlobalEvent {
 802            payload: Box::new(payload),
 803        });
 804    }
 805
 806    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 807    where
 808        E: Entity,
 809        E::Event: 'static,
 810        H: Handle<E>,
 811        F: 'static + FnMut(H, &E::Event, &mut Self),
 812    {
 813        self.subscribe_internal(handle, move |handle, event, cx| {
 814            callback(handle, event, cx);
 815            true
 816        })
 817    }
 818
 819    pub fn subscribe_global<E, F>(&mut self, mut callback: F) -> Subscription
 820    where
 821        E: Any,
 822        F: 'static + FnMut(&E, &mut Self),
 823    {
 824        let subscription_id = post_inc(&mut self.next_subscription_id);
 825        let type_id = TypeId::of::<E>();
 826        self.pending_effects.push_back(Effect::GlobalSubscription {
 827            type_id,
 828            subscription_id,
 829            callback: Box::new(move |payload, cx| {
 830                let payload = payload.downcast_ref().expect("downcast is type safe");
 831                callback(payload, cx)
 832            }),
 833        });
 834        Subscription::GlobalSubscription(
 835            self.global_subscriptions
 836                .subscribe(type_id, subscription_id),
 837        )
 838    }
 839
 840    pub fn observe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 841    where
 842        E: Entity,
 843        E::Event: 'static,
 844        H: Handle<E>,
 845        F: 'static + FnMut(H, &mut Self),
 846    {
 847        self.observe_internal(handle, move |handle, cx| {
 848            callback(handle, cx);
 849            true
 850        })
 851    }
 852
 853    fn subscribe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 854    where
 855        E: Entity,
 856        E::Event: 'static,
 857        H: Handle<E>,
 858        F: 'static + FnMut(H, &E::Event, &mut Self) -> bool,
 859    {
 860        let subscription_id = post_inc(&mut self.next_subscription_id);
 861        let emitter = handle.downgrade();
 862        self.pending_effects.push_back(Effect::Subscription {
 863            entity_id: handle.id(),
 864            subscription_id,
 865            callback: Box::new(move |payload, cx| {
 866                if let Some(emitter) = H::upgrade_from(&emitter, cx) {
 867                    let payload = payload.downcast_ref().expect("downcast is type safe");
 868                    callback(emitter, payload, cx)
 869                } else {
 870                    false
 871                }
 872            }),
 873        });
 874        Subscription::Subscription(self.subscriptions.subscribe(handle.id(), subscription_id))
 875    }
 876
 877    fn observe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 878    where
 879        E: Entity,
 880        E::Event: 'static,
 881        H: Handle<E>,
 882        F: 'static + FnMut(H, &mut Self) -> bool,
 883    {
 884        let subscription_id = post_inc(&mut self.next_subscription_id);
 885        let observed = handle.downgrade();
 886        let entity_id = handle.id();
 887        self.pending_effects.push_back(Effect::Observation {
 888            entity_id,
 889            subscription_id,
 890            callback: Box::new(move |cx| {
 891                if let Some(observed) = H::upgrade_from(&observed, cx) {
 892                    callback(observed, cx)
 893                } else {
 894                    false
 895                }
 896            }),
 897        });
 898        Subscription::Observation(self.observations.subscribe(entity_id, subscription_id))
 899    }
 900
 901    fn observe_focus<F, V>(&mut self, handle: &ViewHandle<V>, mut callback: F) -> Subscription
 902    where
 903        F: 'static + FnMut(ViewHandle<V>, bool, &mut WindowContext) -> bool,
 904        V: View,
 905    {
 906        let subscription_id = post_inc(&mut self.next_subscription_id);
 907        let observed = handle.downgrade();
 908        let view_id = handle.id();
 909
 910        self.pending_effects.push_back(Effect::FocusObservation {
 911            view_id,
 912            subscription_id,
 913            callback: Box::new(move |focused, cx| {
 914                if let Some(observed) = observed.upgrade(cx) {
 915                    callback(observed, focused, cx)
 916                } else {
 917                    false
 918                }
 919            }),
 920        });
 921        Subscription::FocusObservation(self.focus_observations.subscribe(view_id, subscription_id))
 922    }
 923
 924    pub fn observe_global<G, F>(&mut self, mut observe: F) -> Subscription
 925    where
 926        G: Any,
 927        F: 'static + FnMut(&mut AppContext),
 928    {
 929        let type_id = TypeId::of::<G>();
 930        let id = post_inc(&mut self.next_subscription_id);
 931
 932        self.global_observations.add_callback(
 933            type_id,
 934            id,
 935            Box::new(move |cx: &mut AppContext| observe(cx)),
 936        );
 937        Subscription::GlobalObservation(self.global_observations.subscribe(type_id, id))
 938    }
 939
 940    pub fn observe_default_global<G, F>(&mut self, observe: F) -> Subscription
 941    where
 942        G: Any + Default,
 943        F: 'static + FnMut(&mut AppContext),
 944    {
 945        if !self.has_global::<G>() {
 946            self.set_global(G::default());
 947        }
 948        self.observe_global::<G, F>(observe)
 949    }
 950
 951    pub fn observe_release<E, H, F>(&mut self, handle: &H, callback: F) -> Subscription
 952    where
 953        E: Entity,
 954        E::Event: 'static,
 955        H: Handle<E>,
 956        F: 'static + FnOnce(&E, &mut Self),
 957    {
 958        let id = post_inc(&mut self.next_subscription_id);
 959        let mut callback = Some(callback);
 960        self.release_observations.add_callback(
 961            handle.id(),
 962            id,
 963            Box::new(move |released, cx| {
 964                let released = released.downcast_ref().unwrap();
 965                if let Some(callback) = callback.take() {
 966                    callback(released, cx)
 967                }
 968            }),
 969        );
 970        Subscription::ReleaseObservation(self.release_observations.subscribe(handle.id(), id))
 971    }
 972
 973    pub fn observe_actions<F>(&mut self, callback: F) -> Subscription
 974    where
 975        F: 'static + FnMut(TypeId, &mut AppContext),
 976    {
 977        let subscription_id = post_inc(&mut self.next_subscription_id);
 978        self.action_dispatch_observations
 979            .add_callback((), subscription_id, Box::new(callback));
 980        Subscription::ActionObservation(
 981            self.action_dispatch_observations
 982                .subscribe((), subscription_id),
 983        )
 984    }
 985
 986    fn observe_active_labeled_tasks<F>(&mut self, callback: F) -> Subscription
 987    where
 988        F: 'static + FnMut(&mut AppContext) -> bool,
 989    {
 990        let subscription_id = post_inc(&mut self.next_subscription_id);
 991        self.active_labeled_task_observations
 992            .add_callback((), subscription_id, Box::new(callback));
 993        Subscription::ActiveLabeledTasksObservation(
 994            self.active_labeled_task_observations
 995                .subscribe((), subscription_id),
 996        )
 997    }
 998
 999    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut AppContext)) {
1000        self.pending_effects.push_back(Effect::Deferred {
1001            callback: Box::new(callback),
1002            after_window_update: false,
1003        })
1004    }
1005
1006    pub fn after_window_update(&mut self, callback: impl 'static + FnOnce(&mut AppContext)) {
1007        self.pending_effects.push_back(Effect::Deferred {
1008            callback: Box::new(callback),
1009            after_window_update: true,
1010        })
1011    }
1012
1013    fn notify_model(&mut self, model_id: usize) {
1014        if self.pending_notifications.insert(model_id) {
1015            self.pending_effects
1016                .push_back(Effect::ModelNotification { model_id });
1017        }
1018    }
1019
1020    fn notify_view(&mut self, window_id: usize, view_id: usize) {
1021        if self.pending_notifications.insert(view_id) {
1022            self.pending_effects
1023                .push_back(Effect::ViewNotification { window_id, view_id });
1024        }
1025    }
1026
1027    fn notify_global(&mut self, type_id: TypeId) {
1028        if self.pending_global_notifications.insert(type_id) {
1029            self.pending_effects
1030                .push_back(Effect::GlobalNotification { type_id });
1031        }
1032    }
1033
1034    pub fn all_action_names<'a>(&'a self) -> impl Iterator<Item = &'static str> + 'a {
1035        self.action_deserializers.keys().copied()
1036    }
1037
1038    pub fn is_action_available(&self, action: &dyn Action) -> bool {
1039        let mut available_in_window = false;
1040        let action_type = action.as_any().type_id();
1041        if let Some(window_id) = self.platform.main_window_id() {
1042            available_in_window = self
1043                .read_window(window_id, |cx| {
1044                    if let Some(focused_view_id) = cx.focused_view_id() {
1045                        for view_id in cx.ancestors(focused_view_id) {
1046                            if let Some(view) = cx.views.get(&(window_id, view_id)) {
1047                                let view_type = view.as_any().type_id();
1048                                if let Some(actions) = cx.actions.get(&view_type) {
1049                                    if actions.contains_key(&action_type) {
1050                                        return true;
1051                                    }
1052                                }
1053                            }
1054                        }
1055                    }
1056                    false
1057                })
1058                .unwrap_or(false);
1059        }
1060        available_in_window || self.global_actions.contains_key(&action_type)
1061    }
1062
1063    fn actions_mut(
1064        &mut self,
1065        capture_phase: bool,
1066    ) -> &mut HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>> {
1067        if capture_phase {
1068            &mut self.capture_actions
1069        } else {
1070            &mut self.actions
1071        }
1072    }
1073
1074    fn dispatch_global_action_any(&mut self, action: &dyn Action) -> bool {
1075        self.update(|this| {
1076            if let Some((name, mut handler)) = this.global_actions.remove_entry(&action.id()) {
1077                handler(action, this);
1078                this.global_actions.insert(name, handler);
1079                true
1080            } else {
1081                false
1082            }
1083        })
1084    }
1085
1086    pub fn add_bindings<T: IntoIterator<Item = Binding>>(&mut self, bindings: T) {
1087        self.keystroke_matcher.add_bindings(bindings);
1088    }
1089
1090    pub fn clear_bindings(&mut self) {
1091        self.keystroke_matcher.clear_bindings();
1092    }
1093
1094    pub fn default_global<T: 'static + Default>(&mut self) -> &T {
1095        let type_id = TypeId::of::<T>();
1096        self.update(|this| {
1097            if let Entry::Vacant(entry) = this.globals.entry(type_id) {
1098                entry.insert(Box::new(T::default()));
1099                this.notify_global(type_id);
1100            }
1101        });
1102        self.globals.get(&type_id).unwrap().downcast_ref().unwrap()
1103    }
1104
1105    pub fn set_global<T: 'static>(&mut self, state: T) {
1106        self.update(|this| {
1107            let type_id = TypeId::of::<T>();
1108            this.globals.insert(type_id, Box::new(state));
1109            this.notify_global(type_id);
1110        });
1111    }
1112
1113    pub fn update_default_global<T, F, U>(&mut self, update: F) -> U
1114    where
1115        T: 'static + Default,
1116        F: FnOnce(&mut T, &mut AppContext) -> U,
1117    {
1118        self.update(|mut this| {
1119            Self::update_default_global_internal(&mut this, |global, cx| update(global, cx))
1120        })
1121    }
1122
1123    fn update_default_global_internal<C, T, F, U>(this: &mut C, update: F) -> U
1124    where
1125        C: DerefMut<Target = AppContext>,
1126        T: 'static + Default,
1127        F: FnOnce(&mut T, &mut C) -> U,
1128    {
1129        let type_id = TypeId::of::<T>();
1130        let mut state = this
1131            .globals
1132            .remove(&type_id)
1133            .unwrap_or_else(|| Box::new(T::default()));
1134        let result = update(state.downcast_mut().unwrap(), this);
1135        this.globals.insert(type_id, state);
1136        this.notify_global(type_id);
1137        result
1138    }
1139
1140    pub fn update_global<T, F, U>(&mut self, update: F) -> U
1141    where
1142        T: 'static,
1143        F: FnOnce(&mut T, &mut AppContext) -> U,
1144    {
1145        self.update(|mut this| {
1146            Self::update_global_internal(&mut this, |global, cx| update(global, cx))
1147        })
1148    }
1149
1150    fn update_global_internal<C, T, F, U>(this: &mut C, update: F) -> U
1151    where
1152        C: DerefMut<Target = AppContext>,
1153        T: 'static,
1154        F: FnOnce(&mut T, &mut C) -> U,
1155    {
1156        let type_id = TypeId::of::<T>();
1157        if let Some(mut state) = this.globals.remove(&type_id) {
1158            let result = update(state.downcast_mut().unwrap(), this);
1159            this.globals.insert(type_id, state);
1160            this.notify_global(type_id);
1161            result
1162        } else {
1163            panic!("No global added for {}", std::any::type_name::<T>());
1164        }
1165    }
1166
1167    pub fn clear_globals(&mut self) {
1168        self.globals.clear();
1169    }
1170
1171    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
1172    where
1173        T: Entity,
1174        F: FnOnce(&mut ModelContext<T>) -> T,
1175    {
1176        self.update(|this| {
1177            let model_id = post_inc(&mut this.next_entity_id);
1178            let handle = ModelHandle::new(model_id, &this.ref_counts);
1179            let mut cx = ModelContext::new(this, model_id);
1180            let model = build_model(&mut cx);
1181            this.models.insert(model_id, Box::new(model));
1182            handle
1183        })
1184    }
1185
1186    pub fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
1187        if let Some(model) = self.models.get(&handle.model_id) {
1188            model
1189                .as_any()
1190                .downcast_ref()
1191                .expect("downcast is type safe")
1192        } else {
1193            panic!("circular model reference");
1194        }
1195    }
1196
1197    fn update_model<T: Entity, V>(
1198        &mut self,
1199        handle: &ModelHandle<T>,
1200        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> V,
1201    ) -> V {
1202        if let Some(mut model) = self.models.remove(&handle.model_id) {
1203            self.update(|this| {
1204                let mut cx = ModelContext::new(this, handle.model_id);
1205                let result = update(
1206                    model
1207                        .as_any_mut()
1208                        .downcast_mut()
1209                        .expect("downcast is type safe"),
1210                    &mut cx,
1211                );
1212                this.models.insert(handle.model_id, model);
1213                result
1214            })
1215        } else {
1216            panic!("circular model update");
1217        }
1218    }
1219
1220    fn upgrade_model_handle<T: Entity>(
1221        &self,
1222        handle: &WeakModelHandle<T>,
1223    ) -> Option<ModelHandle<T>> {
1224        if self.ref_counts.lock().is_entity_alive(handle.model_id) {
1225            Some(ModelHandle::new(handle.model_id, &self.ref_counts))
1226        } else {
1227            None
1228        }
1229    }
1230
1231    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
1232        self.ref_counts.lock().is_entity_alive(handle.model_id)
1233    }
1234
1235    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
1236        if self.ref_counts.lock().is_entity_alive(handle.model_id) {
1237            Some(AnyModelHandle::new(
1238                handle.model_id,
1239                handle.model_type,
1240                self.ref_counts.clone(),
1241            ))
1242        } else {
1243            None
1244        }
1245    }
1246
1247    pub fn add_window<V, F>(
1248        &mut self,
1249        window_options: WindowOptions,
1250        build_root_view: F,
1251    ) -> (usize, ViewHandle<V>)
1252    where
1253        V: View,
1254        F: FnOnce(&mut ViewContext<V>) -> V,
1255    {
1256        self.update(|this| {
1257            let window_id = post_inc(&mut this.next_window_id);
1258            let platform_window =
1259                this.platform
1260                    .open_window(window_id, window_options, this.foreground.clone());
1261            let window = this.build_window(window_id, platform_window, build_root_view);
1262            let root_view = window.root_view().clone().downcast::<V>().unwrap();
1263            this.windows.insert(window_id, window);
1264            (window_id, root_view)
1265        })
1266    }
1267
1268    pub fn add_status_bar_item<V, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<V>)
1269    where
1270        V: View,
1271        F: FnOnce(&mut ViewContext<V>) -> V,
1272    {
1273        self.update(|this| {
1274            let window_id = post_inc(&mut this.next_window_id);
1275            let platform_window = this.platform.add_status_item(window_id);
1276            let window = this.build_window(window_id, platform_window, build_root_view);
1277            let root_view = window.root_view().clone().downcast::<V>().unwrap();
1278
1279            this.windows.insert(window_id, window);
1280            this.update_window(window_id, |cx| {
1281                root_view.update(cx, |view, cx| view.focus_in(cx.handle().into_any(), cx))
1282            });
1283
1284            (window_id, root_view)
1285        })
1286    }
1287
1288    pub fn build_window<V, F>(
1289        &mut self,
1290        window_id: usize,
1291        mut platform_window: Box<dyn platform::Window>,
1292        build_root_view: F,
1293    ) -> Window
1294    where
1295        V: View,
1296        F: FnOnce(&mut ViewContext<V>) -> V,
1297    {
1298        {
1299            let mut app = self.upgrade();
1300
1301            platform_window.on_event(Box::new(move |event| {
1302                app.update_window(window_id, |cx| {
1303                    if let Event::KeyDown(KeyDownEvent { keystroke, .. }) = &event {
1304                        if cx.dispatch_keystroke(keystroke) {
1305                            return true;
1306                        }
1307                    }
1308
1309                    cx.dispatch_event(event, false)
1310                })
1311                .unwrap_or(false)
1312            }));
1313        }
1314
1315        {
1316            let mut app = self.upgrade();
1317            platform_window.on_active_status_change(Box::new(move |is_active| {
1318                app.update(|cx| cx.window_changed_active_status(window_id, is_active))
1319            }));
1320        }
1321
1322        {
1323            let mut app = self.upgrade();
1324            platform_window.on_resize(Box::new(move || {
1325                app.update(|cx| cx.window_was_resized(window_id))
1326            }));
1327        }
1328
1329        {
1330            let mut app = self.upgrade();
1331            platform_window.on_moved(Box::new(move || {
1332                app.update(|cx| cx.window_was_moved(window_id))
1333            }));
1334        }
1335
1336        {
1337            let mut app = self.upgrade();
1338            platform_window.on_fullscreen(Box::new(move |is_fullscreen| {
1339                app.update(|cx| cx.window_was_fullscreen_changed(window_id, is_fullscreen))
1340            }));
1341        }
1342
1343        {
1344            let mut app = self.upgrade();
1345            platform_window.on_close(Box::new(move || {
1346                app.update(|cx| cx.update_window(window_id, |cx| cx.remove_window()));
1347            }));
1348        }
1349
1350        {
1351            let mut app = self.upgrade();
1352            platform_window
1353                .on_appearance_changed(Box::new(move || app.update(|cx| cx.refresh_windows())));
1354        }
1355
1356        platform_window.set_input_handler(Box::new(WindowInputHandler {
1357            app: self.upgrade().0,
1358            window_id,
1359        }));
1360
1361        let mut window = Window::new(window_id, platform_window, self, build_root_view);
1362        let mut cx = WindowContext::mutable(self, &mut window, window_id);
1363        cx.layout(false).expect("initial layout should not error");
1364        let scene = cx.paint().expect("initial paint should not error");
1365        window.platform_window.present_scene(scene);
1366        window
1367    }
1368
1369    pub fn replace_root_view<V, F>(
1370        &mut self,
1371        window_id: usize,
1372        build_root_view: F,
1373    ) -> Option<ViewHandle<V>>
1374    where
1375        V: View,
1376        F: FnOnce(&mut ViewContext<V>) -> V,
1377    {
1378        self.update_window(window_id, |cx| cx.replace_root_view(build_root_view))
1379    }
1380
1381    pub fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
1382        if let Some(view) = self.views.get(&(handle.window_id, handle.view_id)) {
1383            view.as_any().downcast_ref().expect("downcast is type safe")
1384        } else {
1385            panic!("circular view reference for type {}", type_name::<T>());
1386        }
1387    }
1388
1389    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
1390        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
1391            Some(ViewHandle::new(
1392                handle.window_id,
1393                handle.view_id,
1394                &self.ref_counts,
1395            ))
1396        } else {
1397            None
1398        }
1399    }
1400
1401    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
1402        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
1403            Some(AnyViewHandle::new(
1404                handle.window_id,
1405                handle.view_id,
1406                handle.view_type,
1407                self.ref_counts.clone(),
1408            ))
1409        } else {
1410            None
1411        }
1412    }
1413
1414    fn remove_dropped_entities(&mut self) {
1415        loop {
1416            let (dropped_models, dropped_views, dropped_element_states) =
1417                self.ref_counts.lock().take_dropped();
1418            if dropped_models.is_empty()
1419                && dropped_views.is_empty()
1420                && dropped_element_states.is_empty()
1421            {
1422                break;
1423            }
1424
1425            for model_id in dropped_models {
1426                self.subscriptions.remove(model_id);
1427                self.observations.remove(model_id);
1428                let mut model = self.models.remove(&model_id).unwrap();
1429                model.release(self);
1430                self.pending_effects
1431                    .push_back(Effect::ModelRelease { model_id, model });
1432            }
1433
1434            for (window_id, view_id) in dropped_views {
1435                self.subscriptions.remove(view_id);
1436                self.observations.remove(view_id);
1437                let mut view = self.views.remove(&(window_id, view_id)).unwrap();
1438                view.release(self);
1439                let change_focus_to = self.windows.get_mut(&window_id).and_then(|window| {
1440                    window.parents.remove(&view_id);
1441                    window
1442                        .invalidation
1443                        .get_or_insert_with(Default::default)
1444                        .removed
1445                        .push(view_id);
1446                    if window.focused_view_id == Some(view_id) {
1447                        Some(window.root_view().id())
1448                    } else {
1449                        None
1450                    }
1451                });
1452
1453                if let Some(view_id) = change_focus_to {
1454                    self.pending_effects.push_back(Effect::Focus {
1455                        window_id,
1456                        view_id: Some(view_id),
1457                    });
1458                }
1459
1460                self.pending_effects
1461                    .push_back(Effect::ViewRelease { view_id, view });
1462            }
1463
1464            for key in dropped_element_states {
1465                self.element_states.remove(&key);
1466            }
1467        }
1468    }
1469
1470    fn flush_effects(&mut self) {
1471        self.pending_flushes = self.pending_flushes.saturating_sub(1);
1472        let mut after_window_update_callbacks = Vec::new();
1473
1474        if !self.flushing_effects && self.pending_flushes == 0 {
1475            self.flushing_effects = true;
1476
1477            let mut refreshing = false;
1478            let mut updated_windows = HashSet::default();
1479            let mut focused_views = HashMap::default();
1480            loop {
1481                self.remove_dropped_entities();
1482                if let Some(effect) = self.pending_effects.pop_front() {
1483                    match effect {
1484                        Effect::Subscription {
1485                            entity_id,
1486                            subscription_id,
1487                            callback,
1488                        } => self
1489                            .subscriptions
1490                            .add_callback(entity_id, subscription_id, callback),
1491
1492                        Effect::Event { entity_id, payload } => {
1493                            let mut subscriptions = self.subscriptions.clone();
1494                            subscriptions
1495                                .emit(entity_id, |callback| callback(payload.as_ref(), self))
1496                        }
1497
1498                        Effect::GlobalSubscription {
1499                            type_id,
1500                            subscription_id,
1501                            callback,
1502                        } => self.global_subscriptions.add_callback(
1503                            type_id,
1504                            subscription_id,
1505                            callback,
1506                        ),
1507
1508                        Effect::GlobalEvent { payload } => self.emit_global_event(payload),
1509
1510                        Effect::Observation {
1511                            entity_id,
1512                            subscription_id,
1513                            callback,
1514                        } => self
1515                            .observations
1516                            .add_callback(entity_id, subscription_id, callback),
1517
1518                        Effect::ModelNotification { model_id } => {
1519                            let mut observations = self.observations.clone();
1520                            observations.emit(model_id, |callback| callback(self));
1521                        }
1522
1523                        Effect::ViewNotification { window_id, view_id } => {
1524                            self.handle_view_notification_effect(window_id, view_id)
1525                        }
1526
1527                        Effect::GlobalNotification { type_id } => {
1528                            let mut subscriptions = self.global_observations.clone();
1529                            subscriptions.emit(type_id, |callback| {
1530                                callback(self);
1531                                true
1532                            });
1533                        }
1534
1535                        Effect::Deferred {
1536                            callback,
1537                            after_window_update,
1538                        } => {
1539                            if after_window_update {
1540                                after_window_update_callbacks.push(callback);
1541                            } else {
1542                                callback(self)
1543                            }
1544                        }
1545
1546                        Effect::ModelRelease { model_id, model } => {
1547                            self.handle_entity_release_effect(model_id, model.as_any())
1548                        }
1549
1550                        Effect::ViewRelease { view_id, view } => {
1551                            self.handle_entity_release_effect(view_id, view.as_any())
1552                        }
1553
1554                        Effect::Focus { window_id, view_id } => {
1555                            focused_views.insert(window_id, view_id);
1556                        }
1557
1558                        Effect::FocusObservation {
1559                            view_id,
1560                            subscription_id,
1561                            callback,
1562                        } => {
1563                            self.focus_observations.add_callback(
1564                                view_id,
1565                                subscription_id,
1566                                callback,
1567                            );
1568                        }
1569
1570                        Effect::ResizeWindow { window_id } => {
1571                            if let Some(window) = self.windows.get_mut(&window_id) {
1572                                window
1573                                    .invalidation
1574                                    .get_or_insert(WindowInvalidation::default());
1575                            }
1576                            self.handle_window_moved(window_id);
1577                        }
1578
1579                        Effect::MoveWindow { window_id } => {
1580                            self.handle_window_moved(window_id);
1581                        }
1582
1583                        Effect::WindowActivationObservation {
1584                            window_id,
1585                            subscription_id,
1586                            callback,
1587                        } => self.window_activation_observations.add_callback(
1588                            window_id,
1589                            subscription_id,
1590                            callback,
1591                        ),
1592
1593                        Effect::ActivateWindow {
1594                            window_id,
1595                            is_active,
1596                        } => self.handle_window_activation_effect(window_id, is_active),
1597
1598                        Effect::WindowFullscreenObservation {
1599                            window_id,
1600                            subscription_id,
1601                            callback,
1602                        } => self.window_fullscreen_observations.add_callback(
1603                            window_id,
1604                            subscription_id,
1605                            callback,
1606                        ),
1607
1608                        Effect::FullscreenWindow {
1609                            window_id,
1610                            is_fullscreen,
1611                        } => self.handle_fullscreen_effect(window_id, is_fullscreen),
1612
1613                        Effect::WindowBoundsObservation {
1614                            window_id,
1615                            subscription_id,
1616                            callback,
1617                        } => self.window_bounds_observations.add_callback(
1618                            window_id,
1619                            subscription_id,
1620                            callback,
1621                        ),
1622
1623                        Effect::RefreshWindows => {
1624                            refreshing = true;
1625                        }
1626
1627                        Effect::ActionDispatchNotification { action_id } => {
1628                            self.handle_action_dispatch_notification_effect(action_id)
1629                        }
1630                        Effect::WindowShouldCloseSubscription {
1631                            window_id,
1632                            callback,
1633                        } => {
1634                            self.handle_window_should_close_subscription_effect(window_id, callback)
1635                        }
1636                        Effect::Keystroke {
1637                            window_id,
1638                            keystroke,
1639                            handled_by,
1640                            result,
1641                        } => self.handle_keystroke_effect(window_id, keystroke, handled_by, result),
1642                        Effect::ActiveLabeledTasksChanged => {
1643                            self.handle_active_labeled_tasks_changed_effect()
1644                        }
1645                        Effect::ActiveLabeledTasksObservation {
1646                            subscription_id,
1647                            callback,
1648                        } => self.active_labeled_task_observations.add_callback(
1649                            (),
1650                            subscription_id,
1651                            callback,
1652                        ),
1653                    }
1654                    self.pending_notifications.clear();
1655                } else {
1656                    for window_id in self.windows.keys().cloned().collect::<Vec<_>>() {
1657                        self.update_window(window_id, |cx| {
1658                            let invalidation = if refreshing {
1659                                let mut invalidation =
1660                                    cx.window.invalidation.take().unwrap_or_default();
1661                                invalidation
1662                                    .updated
1663                                    .extend(cx.window.rendered_views.keys().copied());
1664                                Some(invalidation)
1665                            } else {
1666                                cx.window.invalidation.take()
1667                            };
1668
1669                            if let Some(invalidation) = invalidation {
1670                                let appearance = cx.window.platform_window.appearance();
1671                                cx.invalidate(invalidation, appearance);
1672                                if cx.layout(refreshing).log_err().is_some() {
1673                                    updated_windows.insert(window_id);
1674                                }
1675                            }
1676                        });
1677                    }
1678
1679                    for (window_id, view_id) in focused_views.drain() {
1680                        self.handle_focus_effect(window_id, view_id);
1681                    }
1682
1683                    if self.pending_effects.is_empty() {
1684                        for callback in after_window_update_callbacks.drain(..) {
1685                            callback(self);
1686                        }
1687
1688                        for window_id in updated_windows.drain() {
1689                            self.update_window(window_id, |cx| {
1690                                if let Some(scene) = cx.paint().log_err() {
1691                                    cx.window.platform_window.present_scene(scene);
1692                                }
1693                            });
1694                        }
1695
1696                        if self.pending_effects.is_empty() {
1697                            self.flushing_effects = false;
1698                            self.pending_notifications.clear();
1699                            self.pending_global_notifications.clear();
1700                            break;
1701                        }
1702                    }
1703
1704                    refreshing = false;
1705                }
1706            }
1707        }
1708    }
1709
1710    fn window_was_resized(&mut self, window_id: usize) {
1711        self.pending_effects
1712            .push_back(Effect::ResizeWindow { window_id });
1713    }
1714
1715    fn window_was_moved(&mut self, window_id: usize) {
1716        self.pending_effects
1717            .push_back(Effect::MoveWindow { window_id });
1718    }
1719
1720    fn window_was_fullscreen_changed(&mut self, window_id: usize, is_fullscreen: bool) {
1721        self.pending_effects.push_back(Effect::FullscreenWindow {
1722            window_id,
1723            is_fullscreen,
1724        });
1725    }
1726
1727    fn window_changed_active_status(&mut self, window_id: usize, is_active: bool) {
1728        self.pending_effects.push_back(Effect::ActivateWindow {
1729            window_id,
1730            is_active,
1731        });
1732    }
1733
1734    fn keystroke(
1735        &mut self,
1736        window_id: usize,
1737        keystroke: Keystroke,
1738        handled_by: Option<Box<dyn Action>>,
1739        result: MatchResult,
1740    ) {
1741        self.pending_effects.push_back(Effect::Keystroke {
1742            window_id,
1743            keystroke,
1744            handled_by,
1745            result,
1746        });
1747    }
1748
1749    pub fn refresh_windows(&mut self) {
1750        self.pending_effects.push_back(Effect::RefreshWindows);
1751    }
1752
1753    fn emit_global_event(&mut self, payload: Box<dyn Any>) {
1754        let type_id = (&*payload).type_id();
1755
1756        let mut subscriptions = self.global_subscriptions.clone();
1757        subscriptions.emit(type_id, |callback| {
1758            callback(payload.as_ref(), self);
1759            true //Always alive
1760        });
1761    }
1762
1763    fn handle_view_notification_effect(
1764        &mut self,
1765        observed_window_id: usize,
1766        observed_view_id: usize,
1767    ) {
1768        if self
1769            .views
1770            .contains_key(&(observed_window_id, observed_view_id))
1771        {
1772            if let Some(window) = self.windows.get_mut(&observed_window_id) {
1773                window
1774                    .invalidation
1775                    .get_or_insert_with(Default::default)
1776                    .updated
1777                    .insert(observed_view_id);
1778            }
1779
1780            let mut observations = self.observations.clone();
1781            observations.emit(observed_view_id, |callback| callback(self));
1782        }
1783    }
1784
1785    fn handle_entity_release_effect(&mut self, entity_id: usize, entity: &dyn Any) {
1786        self.release_observations
1787            .clone()
1788            .emit(entity_id, |callback| {
1789                callback(entity, self);
1790                // Release observations happen one time. So clear the callback by returning false
1791                false
1792            })
1793    }
1794
1795    fn handle_fullscreen_effect(&mut self, window_id: usize, is_fullscreen: bool) {
1796        self.update_window(window_id, |cx| {
1797            cx.window.is_fullscreen = is_fullscreen;
1798
1799            let mut fullscreen_observations = cx.window_fullscreen_observations.clone();
1800            fullscreen_observations.emit(window_id, |callback| callback(is_fullscreen, cx));
1801
1802            if let Some(uuid) = cx.window_display_uuid() {
1803                let bounds = cx.window_bounds();
1804                let mut bounds_observations = cx.window_bounds_observations.clone();
1805                bounds_observations.emit(window_id, |callback| callback(bounds, uuid, cx));
1806            }
1807
1808            Some(())
1809        });
1810    }
1811
1812    fn handle_keystroke_effect(
1813        &mut self,
1814        window_id: usize,
1815        keystroke: Keystroke,
1816        handled_by: Option<Box<dyn Action>>,
1817        result: MatchResult,
1818    ) {
1819        self.update_window(window_id, |cx| {
1820            let mut observations = cx.keystroke_observations.clone();
1821            observations.emit(window_id, move |callback| {
1822                callback(&keystroke, &result, handled_by.as_ref(), cx)
1823            });
1824        });
1825    }
1826
1827    fn handle_window_activation_effect(&mut self, window_id: usize, active: bool) {
1828        self.update_window(window_id, |cx| {
1829            if cx.window.is_active == active {
1830                return;
1831            }
1832            cx.window.is_active = active;
1833
1834            if let Some(focused_id) = cx.window.focused_view_id {
1835                for view_id in cx.ancestors(focused_id).collect::<Vec<_>>() {
1836                    cx.update_any_view(view_id, |view, cx| {
1837                        if active {
1838                            view.focus_in(focused_id, cx, view_id);
1839                        } else {
1840                            view.focus_out(focused_id, cx, view_id);
1841                        }
1842                    });
1843                }
1844            }
1845
1846            let mut observations = cx.window_activation_observations.clone();
1847            observations.emit(window_id, |callback| callback(active, cx));
1848        });
1849    }
1850
1851    fn handle_focus_effect(&mut self, window_id: usize, mut focused_id: Option<usize>) {
1852        let mut blurred_id = None;
1853        self.update_window(window_id, |cx| {
1854            if cx.window.focused_view_id == focused_id {
1855                focused_id = None;
1856                return;
1857            }
1858            blurred_id = cx.window.focused_view_id;
1859            cx.window.focused_view_id = focused_id;
1860
1861            let blurred_parents = blurred_id
1862                .map(|blurred_id| cx.ancestors(blurred_id).collect::<Vec<_>>())
1863                .unwrap_or_default();
1864            let focused_parents = focused_id
1865                .map(|focused_id| cx.ancestors(focused_id).collect::<Vec<_>>())
1866                .unwrap_or_default();
1867
1868            if let Some(blurred_id) = blurred_id {
1869                for view_id in blurred_parents.iter().copied() {
1870                    if let Some(mut view) = cx.views.remove(&(window_id, view_id)) {
1871                        view.focus_out(blurred_id, cx, view_id);
1872                        cx.views.insert((window_id, view_id), view);
1873                    }
1874                }
1875
1876                let mut subscriptions = cx.focus_observations.clone();
1877                subscriptions.emit(blurred_id, |callback| callback(false, cx));
1878            }
1879
1880            if let Some(focused_id) = focused_id {
1881                for view_id in focused_parents {
1882                    if let Some(mut view) = cx.views.remove(&(window_id, view_id)) {
1883                        view.focus_in(focused_id, cx, view_id);
1884                        cx.views.insert((window_id, view_id), view);
1885                    }
1886                }
1887
1888                let mut subscriptions = cx.focus_observations.clone();
1889                subscriptions.emit(focused_id, |callback| callback(true, cx));
1890            }
1891        });
1892    }
1893
1894    fn handle_action_dispatch_notification_effect(&mut self, action_id: TypeId) {
1895        self.action_dispatch_observations
1896            .clone()
1897            .emit((), |callback| {
1898                callback(action_id, self);
1899                true
1900            });
1901    }
1902
1903    fn handle_window_should_close_subscription_effect(
1904        &mut self,
1905        window_id: usize,
1906        mut callback: WindowShouldCloseSubscriptionCallback,
1907    ) {
1908        let mut app = self.upgrade();
1909        if let Some(window) = self.windows.get_mut(&window_id) {
1910            window
1911                .platform_window
1912                .on_should_close(Box::new(move || app.update(|cx| callback(cx))))
1913        }
1914    }
1915
1916    fn handle_window_moved(&mut self, window_id: usize) {
1917        self.update_window(window_id, |cx| {
1918            if let Some(display) = cx.window_display_uuid() {
1919                let bounds = cx.window_bounds();
1920                cx.window_bounds_observations
1921                    .clone()
1922                    .emit(window_id, move |callback| {
1923                        callback(bounds, display, cx);
1924                        true
1925                    });
1926            }
1927        });
1928    }
1929
1930    fn handle_active_labeled_tasks_changed_effect(&mut self) {
1931        self.active_labeled_task_observations
1932            .clone()
1933            .emit((), move |callback| {
1934                callback(self);
1935                true
1936            });
1937    }
1938
1939    pub fn focus(&mut self, window_id: usize, view_id: Option<usize>) {
1940        self.pending_effects
1941            .push_back(Effect::Focus { window_id, view_id });
1942    }
1943
1944    fn spawn_internal<F, Fut, T>(&mut self, task_name: Option<&'static str>, f: F) -> Task<T>
1945    where
1946        F: FnOnce(AsyncAppContext) -> Fut,
1947        Fut: 'static + Future<Output = T>,
1948        T: 'static,
1949    {
1950        let label_id = task_name.map(|task_name| {
1951            let id = post_inc(&mut self.next_labeled_task_id);
1952            self.active_labeled_tasks.insert(id, task_name);
1953            self.pending_effects
1954                .push_back(Effect::ActiveLabeledTasksChanged);
1955            id
1956        });
1957
1958        let future = f(self.to_async());
1959        let cx = self.to_async();
1960        self.foreground.spawn(async move {
1961            let result = future.await;
1962            let mut cx = cx.0.borrow_mut();
1963
1964            if let Some(completed_label_id) = label_id {
1965                cx.active_labeled_tasks.remove(&completed_label_id);
1966                cx.pending_effects
1967                    .push_back(Effect::ActiveLabeledTasksChanged);
1968            }
1969            cx.flush_effects();
1970            result
1971        })
1972    }
1973
1974    pub fn spawn_labeled<F, Fut, T>(&mut self, task_name: &'static str, f: F) -> Task<T>
1975    where
1976        F: FnOnce(AsyncAppContext) -> Fut,
1977        Fut: 'static + Future<Output = T>,
1978        T: 'static,
1979    {
1980        self.spawn_internal(Some(task_name), f)
1981    }
1982
1983    pub fn spawn<F, Fut, T>(&mut self, f: F) -> Task<T>
1984    where
1985        F: FnOnce(AsyncAppContext) -> Fut,
1986        Fut: 'static + Future<Output = T>,
1987        T: 'static,
1988    {
1989        self.spawn_internal(None, f)
1990    }
1991
1992    pub fn to_async(&self) -> AsyncAppContext {
1993        AsyncAppContext(self.weak_self.as_ref().unwrap().upgrade().unwrap())
1994    }
1995
1996    pub fn write_to_clipboard(&self, item: ClipboardItem) {
1997        self.platform.write_to_clipboard(item);
1998    }
1999
2000    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
2001        self.platform.read_from_clipboard()
2002    }
2003
2004    #[cfg(any(test, feature = "test-support"))]
2005    pub fn leak_detector(&self) -> Arc<Mutex<LeakDetector>> {
2006        self.ref_counts.lock().leak_detector.clone()
2007    }
2008}
2009
2010impl BorrowAppContext for AppContext {
2011    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
2012        f(self)
2013    }
2014
2015    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
2016        f(self)
2017    }
2018}
2019
2020#[derive(Debug)]
2021pub enum ParentId {
2022    View(usize),
2023    Root,
2024}
2025
2026#[derive(Default, Clone)]
2027pub struct WindowInvalidation {
2028    pub updated: HashSet<usize>,
2029    pub removed: Vec<usize>,
2030}
2031
2032pub enum Effect {
2033    Subscription {
2034        entity_id: usize,
2035        subscription_id: usize,
2036        callback: SubscriptionCallback,
2037    },
2038    Event {
2039        entity_id: usize,
2040        payload: Box<dyn Any>,
2041    },
2042    GlobalSubscription {
2043        type_id: TypeId,
2044        subscription_id: usize,
2045        callback: GlobalSubscriptionCallback,
2046    },
2047    GlobalEvent {
2048        payload: Box<dyn Any>,
2049    },
2050    Observation {
2051        entity_id: usize,
2052        subscription_id: usize,
2053        callback: ObservationCallback,
2054    },
2055    ModelNotification {
2056        model_id: usize,
2057    },
2058    ViewNotification {
2059        window_id: usize,
2060        view_id: usize,
2061    },
2062    Deferred {
2063        callback: Box<dyn FnOnce(&mut AppContext)>,
2064        after_window_update: bool,
2065    },
2066    GlobalNotification {
2067        type_id: TypeId,
2068    },
2069    ModelRelease {
2070        model_id: usize,
2071        model: Box<dyn AnyModel>,
2072    },
2073    ViewRelease {
2074        view_id: usize,
2075        view: Box<dyn AnyView>,
2076    },
2077    Focus {
2078        window_id: usize,
2079        view_id: Option<usize>,
2080    },
2081    FocusObservation {
2082        view_id: usize,
2083        subscription_id: usize,
2084        callback: FocusObservationCallback,
2085    },
2086    ResizeWindow {
2087        window_id: usize,
2088    },
2089    MoveWindow {
2090        window_id: usize,
2091    },
2092    ActivateWindow {
2093        window_id: usize,
2094        is_active: bool,
2095    },
2096    WindowActivationObservation {
2097        window_id: usize,
2098        subscription_id: usize,
2099        callback: WindowActivationCallback,
2100    },
2101    FullscreenWindow {
2102        window_id: usize,
2103        is_fullscreen: bool,
2104    },
2105    WindowFullscreenObservation {
2106        window_id: usize,
2107        subscription_id: usize,
2108        callback: WindowFullscreenCallback,
2109    },
2110    WindowBoundsObservation {
2111        window_id: usize,
2112        subscription_id: usize,
2113        callback: WindowBoundsCallback,
2114    },
2115    Keystroke {
2116        window_id: usize,
2117        keystroke: Keystroke,
2118        handled_by: Option<Box<dyn Action>>,
2119        result: MatchResult,
2120    },
2121    RefreshWindows,
2122    ActionDispatchNotification {
2123        action_id: TypeId,
2124    },
2125    WindowShouldCloseSubscription {
2126        window_id: usize,
2127        callback: WindowShouldCloseSubscriptionCallback,
2128    },
2129    ActiveLabeledTasksChanged,
2130    ActiveLabeledTasksObservation {
2131        subscription_id: usize,
2132        callback: ActiveLabeledTasksCallback,
2133    },
2134}
2135
2136impl Debug for Effect {
2137    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2138        match self {
2139            Effect::Subscription {
2140                entity_id,
2141                subscription_id,
2142                ..
2143            } => f
2144                .debug_struct("Effect::Subscribe")
2145                .field("entity_id", entity_id)
2146                .field("subscription_id", subscription_id)
2147                .finish(),
2148            Effect::Event { entity_id, .. } => f
2149                .debug_struct("Effect::Event")
2150                .field("entity_id", entity_id)
2151                .finish(),
2152            Effect::GlobalSubscription {
2153                type_id,
2154                subscription_id,
2155                ..
2156            } => f
2157                .debug_struct("Effect::Subscribe")
2158                .field("type_id", type_id)
2159                .field("subscription_id", subscription_id)
2160                .finish(),
2161            Effect::GlobalEvent { payload, .. } => f
2162                .debug_struct("Effect::GlobalEvent")
2163                .field("type_id", &(&*payload).type_id())
2164                .finish(),
2165            Effect::Observation {
2166                entity_id,
2167                subscription_id,
2168                ..
2169            } => f
2170                .debug_struct("Effect::Observation")
2171                .field("entity_id", entity_id)
2172                .field("subscription_id", subscription_id)
2173                .finish(),
2174            Effect::ModelNotification { model_id } => f
2175                .debug_struct("Effect::ModelNotification")
2176                .field("model_id", model_id)
2177                .finish(),
2178            Effect::ViewNotification { window_id, view_id } => f
2179                .debug_struct("Effect::ViewNotification")
2180                .field("window_id", window_id)
2181                .field("view_id", view_id)
2182                .finish(),
2183            Effect::GlobalNotification { type_id } => f
2184                .debug_struct("Effect::GlobalNotification")
2185                .field("type_id", type_id)
2186                .finish(),
2187            Effect::Deferred { .. } => f.debug_struct("Effect::Deferred").finish(),
2188            Effect::ModelRelease { model_id, .. } => f
2189                .debug_struct("Effect::ModelRelease")
2190                .field("model_id", model_id)
2191                .finish(),
2192            Effect::ViewRelease { view_id, .. } => f
2193                .debug_struct("Effect::ViewRelease")
2194                .field("view_id", view_id)
2195                .finish(),
2196            Effect::Focus { window_id, view_id } => f
2197                .debug_struct("Effect::Focus")
2198                .field("window_id", window_id)
2199                .field("view_id", view_id)
2200                .finish(),
2201            Effect::FocusObservation {
2202                view_id,
2203                subscription_id,
2204                ..
2205            } => f
2206                .debug_struct("Effect::FocusObservation")
2207                .field("view_id", view_id)
2208                .field("subscription_id", subscription_id)
2209                .finish(),
2210            Effect::ActionDispatchNotification { action_id, .. } => f
2211                .debug_struct("Effect::ActionDispatchNotification")
2212                .field("action_id", action_id)
2213                .finish(),
2214            Effect::ResizeWindow { window_id } => f
2215                .debug_struct("Effect::RefreshWindow")
2216                .field("window_id", window_id)
2217                .finish(),
2218            Effect::MoveWindow { window_id } => f
2219                .debug_struct("Effect::MoveWindow")
2220                .field("window_id", window_id)
2221                .finish(),
2222            Effect::WindowActivationObservation {
2223                window_id,
2224                subscription_id,
2225                ..
2226            } => f
2227                .debug_struct("Effect::WindowActivationObservation")
2228                .field("window_id", window_id)
2229                .field("subscription_id", subscription_id)
2230                .finish(),
2231            Effect::ActivateWindow {
2232                window_id,
2233                is_active,
2234            } => f
2235                .debug_struct("Effect::ActivateWindow")
2236                .field("window_id", window_id)
2237                .field("is_active", is_active)
2238                .finish(),
2239            Effect::FullscreenWindow {
2240                window_id,
2241                is_fullscreen,
2242            } => f
2243                .debug_struct("Effect::FullscreenWindow")
2244                .field("window_id", window_id)
2245                .field("is_fullscreen", is_fullscreen)
2246                .finish(),
2247            Effect::WindowFullscreenObservation {
2248                window_id,
2249                subscription_id,
2250                callback: _,
2251            } => f
2252                .debug_struct("Effect::WindowFullscreenObservation")
2253                .field("window_id", window_id)
2254                .field("subscription_id", subscription_id)
2255                .finish(),
2256
2257            Effect::WindowBoundsObservation {
2258                window_id,
2259                subscription_id,
2260                callback: _,
2261            } => f
2262                .debug_struct("Effect::WindowBoundsObservation")
2263                .field("window_id", window_id)
2264                .field("subscription_id", subscription_id)
2265                .finish(),
2266            Effect::RefreshWindows => f.debug_struct("Effect::FullViewRefresh").finish(),
2267            Effect::WindowShouldCloseSubscription { window_id, .. } => f
2268                .debug_struct("Effect::WindowShouldCloseSubscription")
2269                .field("window_id", window_id)
2270                .finish(),
2271            Effect::Keystroke {
2272                window_id,
2273                keystroke,
2274                handled_by,
2275                result,
2276            } => f
2277                .debug_struct("Effect::Keystroke")
2278                .field("window_id", window_id)
2279                .field("keystroke", keystroke)
2280                .field(
2281                    "keystroke",
2282                    &handled_by.as_ref().map(|handled_by| handled_by.name()),
2283                )
2284                .field("result", result)
2285                .finish(),
2286            Effect::ActiveLabeledTasksChanged => {
2287                f.debug_struct("Effect::ActiveLabeledTasksChanged").finish()
2288            }
2289            Effect::ActiveLabeledTasksObservation {
2290                subscription_id,
2291                callback: _,
2292            } => f
2293                .debug_struct("Effect::ActiveLabeledTasksObservation")
2294                .field("subscription_id", subscription_id)
2295                .finish(),
2296        }
2297    }
2298}
2299
2300pub trait AnyModel {
2301    fn as_any(&self) -> &dyn Any;
2302    fn as_any_mut(&mut self) -> &mut dyn Any;
2303    fn release(&mut self, cx: &mut AppContext);
2304    fn app_will_quit(
2305        &mut self,
2306        cx: &mut AppContext,
2307    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
2308}
2309
2310impl<T> AnyModel for T
2311where
2312    T: Entity,
2313{
2314    fn as_any(&self) -> &dyn Any {
2315        self
2316    }
2317
2318    fn as_any_mut(&mut self) -> &mut dyn Any {
2319        self
2320    }
2321
2322    fn release(&mut self, cx: &mut AppContext) {
2323        self.release(cx);
2324    }
2325
2326    fn app_will_quit(
2327        &mut self,
2328        cx: &mut AppContext,
2329    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
2330        self.app_will_quit(cx)
2331    }
2332}
2333
2334pub trait AnyView {
2335    fn as_any(&self) -> &dyn Any;
2336    fn as_any_mut(&mut self) -> &mut dyn Any;
2337    fn release(&mut self, cx: &mut AppContext);
2338    fn app_will_quit(
2339        &mut self,
2340        cx: &mut AppContext,
2341    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
2342    fn ui_name(&self) -> &'static str;
2343    fn render(&mut self, cx: &mut WindowContext, view_id: usize) -> Box<dyn AnyRootElement>;
2344    fn focus_in<'a, 'b>(&mut self, focused_id: usize, cx: &mut WindowContext<'a>, view_id: usize);
2345    fn focus_out(&mut self, focused_id: usize, cx: &mut WindowContext, view_id: usize);
2346    fn key_down(&mut self, event: &KeyDownEvent, cx: &mut WindowContext, view_id: usize) -> bool;
2347    fn key_up(&mut self, event: &KeyUpEvent, cx: &mut WindowContext, view_id: usize) -> bool;
2348    fn modifiers_changed(
2349        &mut self,
2350        event: &ModifiersChangedEvent,
2351        cx: &mut WindowContext,
2352        view_id: usize,
2353    ) -> bool;
2354    fn keymap_context(&self, cx: &AppContext) -> KeymapContext;
2355    fn debug_json(&self, cx: &WindowContext) -> serde_json::Value;
2356
2357    fn text_for_range(&self, range: Range<usize>, cx: &WindowContext) -> Option<String>;
2358    fn selected_text_range(&self, cx: &WindowContext) -> Option<Range<usize>>;
2359    fn marked_text_range(&self, cx: &WindowContext) -> Option<Range<usize>>;
2360    fn unmark_text(&mut self, cx: &mut WindowContext, view_id: usize);
2361    fn replace_text_in_range(
2362        &mut self,
2363        range: Option<Range<usize>>,
2364        text: &str,
2365        cx: &mut WindowContext,
2366        view_id: usize,
2367    );
2368    fn replace_and_mark_text_in_range(
2369        &mut self,
2370        range: Option<Range<usize>>,
2371        new_text: &str,
2372        new_selected_range: Option<Range<usize>>,
2373        cx: &mut WindowContext,
2374        view_id: usize,
2375    );
2376    fn any_handle(&self, window_id: usize, view_id: usize, cx: &AppContext) -> AnyViewHandle {
2377        AnyViewHandle::new(
2378            window_id,
2379            view_id,
2380            self.as_any().type_id(),
2381            cx.ref_counts.clone(),
2382        )
2383    }
2384}
2385
2386impl<V> AnyView for V
2387where
2388    V: View,
2389{
2390    fn as_any(&self) -> &dyn Any {
2391        self
2392    }
2393
2394    fn as_any_mut(&mut self) -> &mut dyn Any {
2395        self
2396    }
2397
2398    fn release(&mut self, cx: &mut AppContext) {
2399        self.release(cx);
2400    }
2401
2402    fn app_will_quit(
2403        &mut self,
2404        cx: &mut AppContext,
2405    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
2406        self.app_will_quit(cx)
2407    }
2408
2409    fn ui_name(&self) -> &'static str {
2410        V::ui_name()
2411    }
2412
2413    fn render(&mut self, cx: &mut WindowContext, view_id: usize) -> Box<dyn AnyRootElement> {
2414        let mut view_context = ViewContext::mutable(cx, view_id);
2415        let element = V::render(self, &mut view_context);
2416        let view = WeakViewHandle::new(cx.window_id, view_id);
2417        Box::new(RootElement::new(element, view))
2418    }
2419
2420    fn focus_in(&mut self, focused_id: usize, cx: &mut WindowContext, view_id: usize) {
2421        let mut cx = ViewContext::mutable(cx, view_id);
2422        let focused_view_handle: AnyViewHandle = if view_id == focused_id {
2423            cx.handle().into_any()
2424        } else {
2425            let focused_type = cx
2426                .views
2427                .get(&(cx.window_id, focused_id))
2428                .unwrap()
2429                .as_any()
2430                .type_id();
2431            AnyViewHandle::new(
2432                cx.window_id,
2433                focused_id,
2434                focused_type,
2435                cx.ref_counts.clone(),
2436            )
2437        };
2438        View::focus_in(self, focused_view_handle, &mut cx);
2439    }
2440
2441    fn focus_out(&mut self, blurred_id: usize, cx: &mut WindowContext, view_id: usize) {
2442        let mut cx = ViewContext::mutable(cx, view_id);
2443        let blurred_view_handle: AnyViewHandle = if view_id == blurred_id {
2444            cx.handle().into_any()
2445        } else {
2446            let blurred_type = cx
2447                .views
2448                .get(&(cx.window_id, blurred_id))
2449                .unwrap()
2450                .as_any()
2451                .type_id();
2452            AnyViewHandle::new(
2453                cx.window_id,
2454                blurred_id,
2455                blurred_type,
2456                cx.ref_counts.clone(),
2457            )
2458        };
2459        View::focus_out(self, blurred_view_handle, &mut cx);
2460    }
2461
2462    fn key_down(&mut self, event: &KeyDownEvent, cx: &mut WindowContext, view_id: usize) -> bool {
2463        let mut cx = ViewContext::mutable(cx, view_id);
2464        View::key_down(self, event, &mut cx)
2465    }
2466
2467    fn key_up(&mut self, event: &KeyUpEvent, cx: &mut WindowContext, view_id: usize) -> bool {
2468        let mut cx = ViewContext::mutable(cx, view_id);
2469        View::key_up(self, event, &mut cx)
2470    }
2471
2472    fn modifiers_changed(
2473        &mut self,
2474        event: &ModifiersChangedEvent,
2475        cx: &mut WindowContext,
2476        view_id: usize,
2477    ) -> bool {
2478        let mut cx = ViewContext::mutable(cx, view_id);
2479        View::modifiers_changed(self, event, &mut cx)
2480    }
2481
2482    fn keymap_context(&self, cx: &AppContext) -> KeymapContext {
2483        View::keymap_context(self, cx)
2484    }
2485
2486    fn debug_json(&self, cx: &WindowContext) -> serde_json::Value {
2487        View::debug_json(self, cx)
2488    }
2489
2490    fn text_for_range(&self, range: Range<usize>, cx: &WindowContext) -> Option<String> {
2491        View::text_for_range(self, range, cx)
2492    }
2493
2494    fn selected_text_range(&self, cx: &WindowContext) -> Option<Range<usize>> {
2495        View::selected_text_range(self, cx)
2496    }
2497
2498    fn marked_text_range(&self, cx: &WindowContext) -> Option<Range<usize>> {
2499        View::marked_text_range(self, cx)
2500    }
2501
2502    fn unmark_text(&mut self, cx: &mut WindowContext, view_id: usize) {
2503        let mut cx = ViewContext::mutable(cx, view_id);
2504        View::unmark_text(self, &mut cx)
2505    }
2506
2507    fn replace_text_in_range(
2508        &mut self,
2509        range: Option<Range<usize>>,
2510        text: &str,
2511        cx: &mut WindowContext,
2512        view_id: usize,
2513    ) {
2514        let mut cx = ViewContext::mutable(cx, view_id);
2515        View::replace_text_in_range(self, range, text, &mut cx)
2516    }
2517
2518    fn replace_and_mark_text_in_range(
2519        &mut self,
2520        range: Option<Range<usize>>,
2521        new_text: &str,
2522        new_selected_range: Option<Range<usize>>,
2523        cx: &mut WindowContext,
2524        view_id: usize,
2525    ) {
2526        let mut cx = ViewContext::mutable(cx, view_id);
2527        View::replace_and_mark_text_in_range(self, range, new_text, new_selected_range, &mut cx)
2528    }
2529}
2530
2531pub struct ModelContext<'a, T: ?Sized> {
2532    app: &'a mut AppContext,
2533    model_id: usize,
2534    model_type: PhantomData<T>,
2535    halt_stream: bool,
2536}
2537
2538impl<'a, T: Entity> ModelContext<'a, T> {
2539    fn new(app: &'a mut AppContext, model_id: usize) -> Self {
2540        Self {
2541            app,
2542            model_id,
2543            model_type: PhantomData,
2544            halt_stream: false,
2545        }
2546    }
2547
2548    pub fn background(&self) -> &Arc<executor::Background> {
2549        &self.app.background
2550    }
2551
2552    pub fn halt_stream(&mut self) {
2553        self.halt_stream = true;
2554    }
2555
2556    pub fn model_id(&self) -> usize {
2557        self.model_id
2558    }
2559
2560    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
2561    where
2562        S: Entity,
2563        F: FnOnce(&mut ModelContext<S>) -> S,
2564    {
2565        self.app.add_model(build_model)
2566    }
2567
2568    pub fn emit(&mut self, payload: T::Event) {
2569        self.app.pending_effects.push_back(Effect::Event {
2570            entity_id: self.model_id,
2571            payload: Box::new(payload),
2572        });
2573    }
2574
2575    pub fn notify(&mut self) {
2576        self.app.notify_model(self.model_id);
2577    }
2578
2579    pub fn subscribe<S: Entity, F>(
2580        &mut self,
2581        handle: &ModelHandle<S>,
2582        mut callback: F,
2583    ) -> Subscription
2584    where
2585        S::Event: 'static,
2586        F: 'static + FnMut(&mut T, ModelHandle<S>, &S::Event, &mut ModelContext<T>),
2587    {
2588        let subscriber = self.weak_handle();
2589        self.app
2590            .subscribe_internal(handle, move |emitter, event, cx| {
2591                if let Some(subscriber) = subscriber.upgrade(cx) {
2592                    subscriber.update(cx, |subscriber, cx| {
2593                        callback(subscriber, emitter, event, cx);
2594                    });
2595                    true
2596                } else {
2597                    false
2598                }
2599            })
2600    }
2601
2602    pub fn observe<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F) -> Subscription
2603    where
2604        S: Entity,
2605        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ModelContext<T>),
2606    {
2607        let observer = self.weak_handle();
2608        self.app.observe_internal(handle, move |observed, cx| {
2609            if let Some(observer) = observer.upgrade(cx) {
2610                observer.update(cx, |observer, cx| {
2611                    callback(observer, observed, cx);
2612                });
2613                true
2614            } else {
2615                false
2616            }
2617        })
2618    }
2619
2620    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
2621    where
2622        G: Any,
2623        F: 'static + FnMut(&mut T, &mut ModelContext<T>),
2624    {
2625        let observer = self.weak_handle();
2626        self.app.observe_global::<G, _>(move |cx| {
2627            if let Some(observer) = observer.upgrade(cx) {
2628                observer.update(cx, |observer, cx| callback(observer, cx));
2629            }
2630        })
2631    }
2632
2633    pub fn observe_release<S, F>(
2634        &mut self,
2635        handle: &ModelHandle<S>,
2636        mut callback: F,
2637    ) -> Subscription
2638    where
2639        S: Entity,
2640        F: 'static + FnMut(&mut T, &S, &mut ModelContext<T>),
2641    {
2642        let observer = self.weak_handle();
2643        self.app.observe_release(handle, move |released, cx| {
2644            if let Some(observer) = observer.upgrade(cx) {
2645                observer.update(cx, |observer, cx| {
2646                    callback(observer, released, cx);
2647                });
2648            }
2649        })
2650    }
2651
2652    pub fn handle(&self) -> ModelHandle<T> {
2653        ModelHandle::new(self.model_id, &self.app.ref_counts)
2654    }
2655
2656    pub fn weak_handle(&self) -> WeakModelHandle<T> {
2657        WeakModelHandle::new(self.model_id)
2658    }
2659
2660    pub fn spawn<F, Fut, S>(&mut self, f: F) -> Task<S>
2661    where
2662        F: FnOnce(ModelHandle<T>, AsyncAppContext) -> Fut,
2663        Fut: 'static + Future<Output = S>,
2664        S: 'static,
2665    {
2666        let handle = self.handle();
2667        self.app.spawn(|cx| f(handle, cx))
2668    }
2669
2670    pub fn spawn_weak<F, Fut, S>(&mut self, f: F) -> Task<S>
2671    where
2672        F: FnOnce(WeakModelHandle<T>, AsyncAppContext) -> Fut,
2673        Fut: 'static + Future<Output = S>,
2674        S: 'static,
2675    {
2676        let handle = self.weak_handle();
2677        self.app.spawn(|cx| f(handle, cx))
2678    }
2679}
2680
2681impl<M> AsRef<AppContext> for ModelContext<'_, M> {
2682    fn as_ref(&self) -> &AppContext {
2683        &self.app
2684    }
2685}
2686
2687impl<M> AsMut<AppContext> for ModelContext<'_, M> {
2688    fn as_mut(&mut self) -> &mut AppContext {
2689        self.app
2690    }
2691}
2692
2693impl<M> BorrowAppContext for ModelContext<'_, M> {
2694    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
2695        self.app.read_with(f)
2696    }
2697
2698    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
2699        self.app.update(f)
2700    }
2701}
2702
2703impl<M> Deref for ModelContext<'_, M> {
2704    type Target = AppContext;
2705
2706    fn deref(&self) -> &Self::Target {
2707        self.app
2708    }
2709}
2710
2711impl<M> DerefMut for ModelContext<'_, M> {
2712    fn deref_mut(&mut self) -> &mut Self::Target {
2713        &mut self.app
2714    }
2715}
2716
2717pub struct ViewContext<'a, 'b, T: ?Sized> {
2718    window_context: Reference<'b, WindowContext<'a>>,
2719    view_id: usize,
2720    view_type: PhantomData<T>,
2721}
2722
2723impl<'a, 'b, T: View> Deref for ViewContext<'a, 'b, T> {
2724    type Target = WindowContext<'a>;
2725
2726    fn deref(&self) -> &Self::Target {
2727        &self.window_context
2728    }
2729}
2730
2731impl<T: View> DerefMut for ViewContext<'_, '_, T> {
2732    fn deref_mut(&mut self) -> &mut Self::Target {
2733        &mut self.window_context
2734    }
2735}
2736
2737impl<'a, 'b, V: View> ViewContext<'a, 'b, V> {
2738    pub(crate) fn mutable(window_context: &'b mut WindowContext<'a>, view_id: usize) -> Self {
2739        Self {
2740            window_context: Reference::Mutable(window_context),
2741            view_id,
2742            view_type: PhantomData,
2743        }
2744    }
2745
2746    pub(crate) fn immutable(window_context: &'b WindowContext<'a>, view_id: usize) -> Self {
2747        Self {
2748            window_context: Reference::Immutable(window_context),
2749            view_id,
2750            view_type: PhantomData,
2751        }
2752    }
2753
2754    pub fn window_context(&mut self) -> &mut WindowContext<'a> {
2755        &mut self.window_context
2756    }
2757
2758    pub fn handle(&self) -> ViewHandle<V> {
2759        ViewHandle::new(
2760            self.window_id,
2761            self.view_id,
2762            &self.window_context.ref_counts,
2763        )
2764    }
2765
2766    pub fn weak_handle(&self) -> WeakViewHandle<V> {
2767        WeakViewHandle::new(self.window_id, self.view_id)
2768    }
2769
2770    pub fn parent(&self) -> Option<usize> {
2771        self.window_context.parent(self.view_id)
2772    }
2773
2774    pub fn window_id(&self) -> usize {
2775        self.window_id
2776    }
2777
2778    pub fn view_id(&self) -> usize {
2779        self.view_id
2780    }
2781
2782    pub fn foreground(&self) -> &Rc<executor::Foreground> {
2783        self.window_context.foreground()
2784    }
2785
2786    pub fn background_executor(&self) -> &Arc<executor::Background> {
2787        &self.window_context.background
2788    }
2789
2790    pub fn platform(&self) -> &Arc<dyn Platform> {
2791        self.window_context.platform()
2792    }
2793
2794    pub fn prompt_for_paths(
2795        &self,
2796        options: PathPromptOptions,
2797    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
2798        self.window_context.prompt_for_paths(options)
2799    }
2800
2801    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
2802        self.window_context.prompt_for_new_path(directory)
2803    }
2804
2805    pub fn reveal_path(&self, path: &Path) {
2806        self.window_context.reveal_path(path)
2807    }
2808
2809    pub fn focus(&mut self, handle: &AnyViewHandle) {
2810        self.window_context
2811            .focus(handle.window_id, Some(handle.view_id));
2812    }
2813
2814    pub fn focus_self(&mut self) {
2815        let window_id = self.window_id;
2816        let view_id = self.view_id;
2817        self.window_context.focus(window_id, Some(view_id));
2818    }
2819
2820    pub fn is_self_focused(&self) -> bool {
2821        self.window.focused_view_id == Some(self.view_id)
2822    }
2823
2824    pub fn is_parent_view_focused(&self) -> bool {
2825        if let Some(parent_view_id) = self.ancestors(self.view_id).next().clone() {
2826            self.focused_view_id() == Some(parent_view_id)
2827        } else {
2828            false
2829        }
2830    }
2831
2832    pub fn focus_parent_view(&mut self) {
2833        let next = self.ancestors(self.view_id).next().clone();
2834        if let Some(parent_view_id) = next {
2835            let window_id = self.window_id;
2836            self.window_context.focus(window_id, Some(parent_view_id));
2837        }
2838    }
2839
2840    pub fn is_child(&self, view: impl Into<AnyViewHandle>) -> bool {
2841        let view = view.into();
2842        if self.window_id != view.window_id {
2843            return false;
2844        }
2845        self.ancestors(view.view_id)
2846            .skip(1) // Skip self id
2847            .any(|parent| parent == self.view_id)
2848    }
2849
2850    pub fn blur(&mut self) {
2851        let window_id = self.window_id;
2852        self.window_context.focus(window_id, None);
2853    }
2854
2855    pub fn on_window_should_close<F>(&mut self, mut callback: F)
2856    where
2857        F: 'static + FnMut(&mut V, &mut ViewContext<V>) -> bool,
2858    {
2859        let window_id = self.window_id;
2860        let view = self.weak_handle();
2861        self.pending_effects
2862            .push_back(Effect::WindowShouldCloseSubscription {
2863                window_id,
2864                callback: Box::new(move |cx| {
2865                    cx.update_window(window_id, |cx| {
2866                        if let Some(view) = view.upgrade(cx) {
2867                            view.update(cx, |view, cx| callback(view, cx))
2868                        } else {
2869                            true
2870                        }
2871                    })
2872                    .unwrap_or(true)
2873                }),
2874            });
2875    }
2876
2877    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
2878    where
2879        E: Entity,
2880        E::Event: 'static,
2881        H: Handle<E>,
2882        F: 'static + FnMut(&mut V, H, &E::Event, &mut ViewContext<V>),
2883    {
2884        let subscriber = self.weak_handle();
2885        self.window_context
2886            .subscribe_internal(handle, move |emitter, event, cx| {
2887                if let Some(subscriber) = subscriber.upgrade(cx) {
2888                    subscriber.update(cx, |subscriber, cx| {
2889                        callback(subscriber, emitter, event, cx);
2890                    });
2891                    true
2892                } else {
2893                    false
2894                }
2895            })
2896    }
2897
2898    pub fn observe<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
2899    where
2900        E: Entity,
2901        H: Handle<E>,
2902        F: 'static + FnMut(&mut V, H, &mut ViewContext<V>),
2903    {
2904        let window_id = self.window_id;
2905        let observer = self.weak_handle();
2906        self.window_context
2907            .observe_internal(handle, move |observed, cx| {
2908                cx.update_window(window_id, |cx| {
2909                    if let Some(observer) = observer.upgrade(cx) {
2910                        observer.update(cx, |observer, cx| {
2911                            callback(observer, observed, cx);
2912                        });
2913                        true
2914                    } else {
2915                        false
2916                    }
2917                })
2918                .unwrap_or(false)
2919            })
2920    }
2921
2922    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
2923    where
2924        G: Any,
2925        F: 'static + FnMut(&mut V, &mut ViewContext<V>),
2926    {
2927        let window_id = self.window_id;
2928        let observer = self.weak_handle();
2929        self.window_context.observe_global::<G, _>(move |cx| {
2930            cx.update_window(window_id, |cx| {
2931                if let Some(observer) = observer.upgrade(cx) {
2932                    observer.update(cx, |observer, cx| callback(observer, cx));
2933                }
2934            });
2935        })
2936    }
2937
2938    pub fn observe_focus<F, W>(&mut self, handle: &ViewHandle<W>, mut callback: F) -> Subscription
2939    where
2940        F: 'static + FnMut(&mut V, ViewHandle<W>, bool, &mut ViewContext<V>),
2941        W: View,
2942    {
2943        let observer = self.weak_handle();
2944        self.window_context
2945            .observe_focus(handle, move |observed, focused, cx| {
2946                if let Some(observer) = observer.upgrade(cx) {
2947                    observer.update(cx, |observer, cx| {
2948                        callback(observer, observed, focused, cx);
2949                    });
2950                    true
2951                } else {
2952                    false
2953                }
2954            })
2955    }
2956
2957    pub fn observe_release<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
2958    where
2959        E: Entity,
2960        H: Handle<E>,
2961        F: 'static + FnMut(&mut V, &E, &mut ViewContext<V>),
2962    {
2963        let window_id = self.window_id;
2964        let observer = self.weak_handle();
2965        self.window_context
2966            .observe_release(handle, move |released, cx| {
2967                cx.update_window(window_id, |cx| {
2968                    if let Some(observer) = observer.upgrade(cx) {
2969                        observer.update(cx, |observer, cx| {
2970                            callback(observer, released, cx);
2971                        });
2972                    }
2973                });
2974            })
2975    }
2976
2977    pub fn observe_actions<F>(&mut self, mut callback: F) -> Subscription
2978    where
2979        F: 'static + FnMut(&mut V, TypeId, &mut ViewContext<V>),
2980    {
2981        let window_id = self.window_id;
2982        let observer = self.weak_handle();
2983        self.window_context.observe_actions(move |action_id, cx| {
2984            cx.update_window(window_id, |cx| {
2985                if let Some(observer) = observer.upgrade(cx) {
2986                    observer.update(cx, |observer, cx| {
2987                        callback(observer, action_id, cx);
2988                    });
2989                }
2990            });
2991        })
2992    }
2993
2994    pub fn observe_window_activation<F>(&mut self, mut callback: F) -> Subscription
2995    where
2996        F: 'static + FnMut(&mut V, bool, &mut ViewContext<V>),
2997    {
2998        let observer = self.weak_handle();
2999        self.window_context
3000            .observe_window_activation(move |active, cx| {
3001                if let Some(observer) = observer.upgrade(cx) {
3002                    observer.update(cx, |observer, cx| {
3003                        callback(observer, active, cx);
3004                    });
3005                    true
3006                } else {
3007                    false
3008                }
3009            })
3010    }
3011
3012    pub fn observe_fullscreen<F>(&mut self, mut callback: F) -> Subscription
3013    where
3014        F: 'static + FnMut(&mut V, bool, &mut ViewContext<V>),
3015    {
3016        let observer = self.weak_handle();
3017        self.window_context.observe_fullscreen(move |active, cx| {
3018            if let Some(observer) = observer.upgrade(cx) {
3019                observer.update(cx, |observer, cx| {
3020                    callback(observer, active, cx);
3021                });
3022                true
3023            } else {
3024                false
3025            }
3026        })
3027    }
3028
3029    pub fn observe_keystrokes<F>(&mut self, mut callback: F) -> Subscription
3030    where
3031        F: 'static
3032            + FnMut(
3033                &mut V,
3034                &Keystroke,
3035                Option<&Box<dyn Action>>,
3036                &MatchResult,
3037                &mut ViewContext<V>,
3038            ) -> bool,
3039    {
3040        let observer = self.weak_handle();
3041        self.window_context
3042            .observe_keystrokes(move |keystroke, result, handled_by, cx| {
3043                if let Some(observer) = observer.upgrade(cx) {
3044                    observer.update(cx, |observer, cx| {
3045                        callback(observer, keystroke, handled_by, result, cx);
3046                    });
3047                    true
3048                } else {
3049                    false
3050                }
3051            })
3052    }
3053
3054    pub fn observe_window_bounds<F>(&mut self, mut callback: F) -> Subscription
3055    where
3056        F: 'static + FnMut(&mut V, WindowBounds, Uuid, &mut ViewContext<V>),
3057    {
3058        let observer = self.weak_handle();
3059        self.window_context
3060            .observe_window_bounds(move |bounds, display, cx| {
3061                if let Some(observer) = observer.upgrade(cx) {
3062                    observer.update(cx, |observer, cx| {
3063                        callback(observer, bounds, display, cx);
3064                    });
3065                    true
3066                } else {
3067                    false
3068                }
3069            })
3070    }
3071
3072    pub fn observe_active_labeled_tasks<F>(&mut self, mut callback: F) -> Subscription
3073    where
3074        F: 'static + FnMut(&mut V, &mut ViewContext<V>),
3075    {
3076        let window_id = self.window_id;
3077        let observer = self.weak_handle();
3078        self.window_context.observe_active_labeled_tasks(move |cx| {
3079            cx.update_window(window_id, |cx| {
3080                if let Some(observer) = observer.upgrade(cx) {
3081                    observer.update(cx, |observer, cx| {
3082                        callback(observer, cx);
3083                    });
3084                    true
3085                } else {
3086                    false
3087                }
3088            })
3089            .unwrap_or(false)
3090        })
3091    }
3092
3093    pub fn emit(&mut self, payload: V::Event) {
3094        self.window_context
3095            .pending_effects
3096            .push_back(Effect::Event {
3097                entity_id: self.view_id,
3098                payload: Box::new(payload),
3099            });
3100    }
3101
3102    pub fn notify(&mut self) {
3103        let window_id = self.window_id;
3104        let view_id = self.view_id;
3105        self.window_context.notify_view(window_id, view_id);
3106    }
3107
3108    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut V, &mut ViewContext<V>)) {
3109        let handle = self.handle();
3110        self.window_context
3111            .defer(move |cx| handle.update(cx, |view, cx| callback(view, cx)))
3112    }
3113
3114    pub fn after_window_update(
3115        &mut self,
3116        callback: impl 'static + FnOnce(&mut V, &mut ViewContext<V>),
3117    ) {
3118        let window_id = self.window_id;
3119        let handle = self.handle();
3120        self.window_context.after_window_update(move |cx| {
3121            cx.update_window(window_id, |cx| {
3122                handle.update(cx, |view, cx| {
3123                    callback(view, cx);
3124                })
3125            });
3126        })
3127    }
3128
3129    pub fn propagate_action(&mut self) {
3130        self.window_context.halt_action_dispatch = false;
3131    }
3132
3133    pub fn spawn_labeled<F, Fut, S>(&mut self, task_label: &'static str, f: F) -> Task<S>
3134    where
3135        F: FnOnce(WeakViewHandle<V>, AsyncAppContext) -> Fut,
3136        Fut: 'static + Future<Output = S>,
3137        S: 'static,
3138    {
3139        let handle = self.weak_handle();
3140        self.window_context
3141            .spawn_labeled(task_label, |cx| f(handle, cx))
3142    }
3143
3144    pub fn spawn<F, Fut, S>(&mut self, f: F) -> Task<S>
3145    where
3146        F: FnOnce(WeakViewHandle<V>, AsyncAppContext) -> Fut,
3147        Fut: 'static + Future<Output = S>,
3148        S: 'static,
3149    {
3150        let handle = self.weak_handle();
3151        self.window_context.spawn(|cx| f(handle, cx))
3152    }
3153
3154    pub fn mouse_state<Tag: 'static>(&self, region_id: usize) -> MouseState {
3155        let region_id = MouseRegionId::new::<Tag>(self.view_id, region_id);
3156        MouseState {
3157            hovered: self.window.hovered_region_ids.contains(&region_id),
3158            clicked: self
3159                .window
3160                .clicked_region_ids
3161                .get(&region_id)
3162                .and_then(|_| self.window.clicked_button),
3163            accessed_hovered: false,
3164            accessed_clicked: false,
3165        }
3166    }
3167
3168    pub fn element_state<Tag: 'static, T: 'static>(
3169        &mut self,
3170        element_id: usize,
3171        initial: T,
3172    ) -> ElementStateHandle<T> {
3173        let id = ElementStateId {
3174            view_id: self.view_id(),
3175            element_id,
3176            tag: TypeId::of::<Tag>(),
3177        };
3178        self.element_states
3179            .entry(id)
3180            .or_insert_with(|| Box::new(initial));
3181        ElementStateHandle::new(id, self.frame_count, &self.ref_counts)
3182    }
3183
3184    pub fn default_element_state<Tag: 'static, T: 'static + Default>(
3185        &mut self,
3186        element_id: usize,
3187    ) -> ElementStateHandle<T> {
3188        self.element_state::<Tag, T>(element_id, T::default())
3189    }
3190}
3191
3192impl<V> BorrowAppContext for ViewContext<'_, '_, V> {
3193    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
3194        BorrowAppContext::read_with(&*self.window_context, f)
3195    }
3196
3197    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
3198        BorrowAppContext::update(&mut *self.window_context, f)
3199    }
3200}
3201
3202impl<V> BorrowWindowContext for ViewContext<'_, '_, V> {
3203    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T {
3204        BorrowWindowContext::read_with(&*self.window_context, window_id, f)
3205    }
3206
3207    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T {
3208        BorrowWindowContext::update(&mut *self.window_context, window_id, f)
3209    }
3210}
3211
3212pub struct LayoutContext<'a, 'b, 'c, V: View> {
3213    view_context: &'c mut ViewContext<'a, 'b, V>,
3214    new_parents: &'c mut HashMap<usize, usize>,
3215    views_to_notify_if_ancestors_change: &'c mut HashSet<usize>,
3216    pub refreshing: bool,
3217}
3218
3219impl<'a, 'b, 'c, V: View> LayoutContext<'a, 'b, 'c, V> {
3220    pub fn new(
3221        view_context: &'c mut ViewContext<'a, 'b, V>,
3222        new_parents: &'c mut HashMap<usize, usize>,
3223        views_to_notify_if_ancestors_change: &'c mut HashSet<usize>,
3224        refreshing: bool,
3225    ) -> Self {
3226        Self {
3227            view_context,
3228            new_parents,
3229            views_to_notify_if_ancestors_change,
3230            refreshing,
3231        }
3232    }
3233
3234    pub fn view_context(&mut self) -> &mut ViewContext<'a, 'b, V> {
3235        self.view_context
3236    }
3237}
3238
3239impl<'a, 'b, 'c, V: View> Deref for LayoutContext<'a, 'b, 'c, V> {
3240    type Target = ViewContext<'a, 'b, V>;
3241
3242    fn deref(&self) -> &Self::Target {
3243        &self.view_context
3244    }
3245}
3246
3247impl<V: View> DerefMut for LayoutContext<'_, '_, '_, V> {
3248    fn deref_mut(&mut self) -> &mut Self::Target {
3249        &mut self.view_context
3250    }
3251}
3252
3253impl<V: View> BorrowAppContext for LayoutContext<'_, '_, '_, V> {
3254    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
3255        BorrowAppContext::read_with(&*self.view_context, f)
3256    }
3257
3258    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
3259        BorrowAppContext::update(&mut *self.view_context, f)
3260    }
3261}
3262
3263impl<V: View> BorrowWindowContext for LayoutContext<'_, '_, '_, V> {
3264    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T {
3265        BorrowWindowContext::read_with(&*self.view_context, window_id, f)
3266    }
3267
3268    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T {
3269        BorrowWindowContext::update(&mut *self.view_context, window_id, f)
3270    }
3271}
3272
3273pub struct EventContext<'a, 'b, 'c, V: View> {
3274    view_context: &'c mut ViewContext<'a, 'b, V>,
3275    pub(crate) handled: bool,
3276}
3277
3278impl<'a, 'b, 'c, V: View> EventContext<'a, 'b, 'c, V> {
3279    pub(crate) fn new(view_context: &'c mut ViewContext<'a, 'b, V>) -> Self {
3280        EventContext {
3281            view_context,
3282            handled: true,
3283        }
3284    }
3285
3286    pub fn propagate_event(&mut self) {
3287        self.handled = false;
3288    }
3289}
3290
3291impl<'a, 'b, 'c, V: View> Deref for EventContext<'a, 'b, 'c, V> {
3292    type Target = ViewContext<'a, 'b, V>;
3293
3294    fn deref(&self) -> &Self::Target {
3295        &self.view_context
3296    }
3297}
3298
3299impl<V: View> DerefMut for EventContext<'_, '_, '_, V> {
3300    fn deref_mut(&mut self) -> &mut Self::Target {
3301        &mut self.view_context
3302    }
3303}
3304
3305impl<V: View> BorrowAppContext for EventContext<'_, '_, '_, V> {
3306    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
3307        BorrowAppContext::read_with(&*self.view_context, f)
3308    }
3309
3310    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
3311        BorrowAppContext::update(&mut *self.view_context, f)
3312    }
3313}
3314
3315impl<V: View> BorrowWindowContext for EventContext<'_, '_, '_, V> {
3316    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T {
3317        BorrowWindowContext::read_with(&*self.view_context, window_id, f)
3318    }
3319
3320    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T {
3321        BorrowWindowContext::update(&mut *self.view_context, window_id, f)
3322    }
3323}
3324
3325pub(crate) enum Reference<'a, T> {
3326    Immutable(&'a T),
3327    Mutable(&'a mut T),
3328}
3329
3330impl<'a, T> Deref for Reference<'a, T> {
3331    type Target = T;
3332
3333    fn deref(&self) -> &Self::Target {
3334        match self {
3335            Reference::Immutable(target) => target,
3336            Reference::Mutable(target) => target,
3337        }
3338    }
3339}
3340
3341impl<'a, T> DerefMut for Reference<'a, T> {
3342    fn deref_mut(&mut self) -> &mut Self::Target {
3343        match self {
3344            Reference::Immutable(_) => {
3345                panic!("cannot mutably deref an immutable reference. this is a bug in GPUI.");
3346            }
3347            Reference::Mutable(target) => target,
3348        }
3349    }
3350}
3351
3352#[derive(Debug, Clone, Default)]
3353pub struct MouseState {
3354    pub(crate) hovered: bool,
3355    pub(crate) clicked: Option<MouseButton>,
3356    pub(crate) accessed_hovered: bool,
3357    pub(crate) accessed_clicked: bool,
3358}
3359
3360impl MouseState {
3361    pub fn hovered(&mut self) -> bool {
3362        self.accessed_hovered = true;
3363        self.hovered
3364    }
3365
3366    pub fn clicked(&mut self) -> Option<MouseButton> {
3367        self.accessed_clicked = true;
3368        self.clicked
3369    }
3370
3371    pub fn accessed_hovered(&self) -> bool {
3372        self.accessed_hovered
3373    }
3374
3375    pub fn accessed_clicked(&self) -> bool {
3376        self.accessed_clicked
3377    }
3378}
3379
3380pub trait Handle<T> {
3381    type Weak: 'static;
3382    fn id(&self) -> usize;
3383    fn location(&self) -> EntityLocation;
3384    fn downgrade(&self) -> Self::Weak;
3385    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
3386    where
3387        Self: Sized;
3388}
3389
3390pub trait WeakHandle {
3391    fn id(&self) -> usize;
3392}
3393
3394#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
3395pub enum EntityLocation {
3396    Model(usize),
3397    View(usize, usize),
3398}
3399
3400pub struct ModelHandle<T: Entity> {
3401    any_handle: AnyModelHandle,
3402    model_type: PhantomData<T>,
3403}
3404
3405impl<T: Entity> Deref for ModelHandle<T> {
3406    type Target = AnyModelHandle;
3407
3408    fn deref(&self) -> &Self::Target {
3409        &self.any_handle
3410    }
3411}
3412
3413impl<T: Entity> ModelHandle<T> {
3414    fn new(model_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
3415        Self {
3416            any_handle: AnyModelHandle::new(model_id, TypeId::of::<T>(), ref_counts.clone()),
3417            model_type: PhantomData,
3418        }
3419    }
3420
3421    pub fn downgrade(&self) -> WeakModelHandle<T> {
3422        WeakModelHandle::new(self.model_id)
3423    }
3424
3425    pub fn id(&self) -> usize {
3426        self.model_id
3427    }
3428
3429    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
3430        cx.read_model(self)
3431    }
3432
3433    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
3434    where
3435        C: BorrowAppContext,
3436        F: FnOnce(&T, &AppContext) -> S,
3437    {
3438        cx.read_with(|cx| read(self.read(cx), cx))
3439    }
3440
3441    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
3442    where
3443        C: BorrowAppContext,
3444        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
3445    {
3446        let mut update = Some(update);
3447        cx.update(|cx| {
3448            cx.update_model(self, &mut |model, cx| {
3449                let update = update.take().unwrap();
3450                update(model, cx)
3451            })
3452        })
3453    }
3454}
3455
3456impl<T: Entity> Clone for ModelHandle<T> {
3457    fn clone(&self) -> Self {
3458        Self::new(self.model_id, &self.ref_counts)
3459    }
3460}
3461
3462impl<T: Entity> PartialEq for ModelHandle<T> {
3463    fn eq(&self, other: &Self) -> bool {
3464        self.model_id == other.model_id
3465    }
3466}
3467
3468impl<T: Entity> Eq for ModelHandle<T> {}
3469
3470impl<T: Entity> PartialEq<WeakModelHandle<T>> for ModelHandle<T> {
3471    fn eq(&self, other: &WeakModelHandle<T>) -> bool {
3472        self.model_id == other.model_id
3473    }
3474}
3475
3476impl<T: Entity> Hash for ModelHandle<T> {
3477    fn hash<H: Hasher>(&self, state: &mut H) {
3478        self.model_id.hash(state);
3479    }
3480}
3481
3482impl<T: Entity> std::borrow::Borrow<usize> for ModelHandle<T> {
3483    fn borrow(&self) -> &usize {
3484        &self.model_id
3485    }
3486}
3487
3488impl<T: Entity> Debug for ModelHandle<T> {
3489    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3490        f.debug_tuple(&format!("ModelHandle<{}>", type_name::<T>()))
3491            .field(&self.model_id)
3492            .finish()
3493    }
3494}
3495
3496unsafe impl<T: Entity> Send for ModelHandle<T> {}
3497unsafe impl<T: Entity> Sync for ModelHandle<T> {}
3498
3499impl<T: Entity> Handle<T> for ModelHandle<T> {
3500    type Weak = WeakModelHandle<T>;
3501
3502    fn id(&self) -> usize {
3503        self.model_id
3504    }
3505
3506    fn location(&self) -> EntityLocation {
3507        EntityLocation::Model(self.model_id)
3508    }
3509
3510    fn downgrade(&self) -> Self::Weak {
3511        self.downgrade()
3512    }
3513
3514    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
3515    where
3516        Self: Sized,
3517    {
3518        weak.upgrade(cx)
3519    }
3520}
3521
3522pub struct WeakModelHandle<T> {
3523    any_handle: AnyWeakModelHandle,
3524    model_type: PhantomData<T>,
3525}
3526
3527impl<T> WeakModelHandle<T> {
3528    pub fn into_any(self) -> AnyWeakModelHandle {
3529        self.any_handle
3530    }
3531}
3532
3533impl<T> Deref for WeakModelHandle<T> {
3534    type Target = AnyWeakModelHandle;
3535
3536    fn deref(&self) -> &Self::Target {
3537        &self.any_handle
3538    }
3539}
3540
3541impl<T> WeakHandle for WeakModelHandle<T> {
3542    fn id(&self) -> usize {
3543        self.model_id
3544    }
3545}
3546
3547unsafe impl<T> Send for WeakModelHandle<T> {}
3548unsafe impl<T> Sync for WeakModelHandle<T> {}
3549
3550impl<T: Entity> WeakModelHandle<T> {
3551    fn new(model_id: usize) -> Self {
3552        Self {
3553            any_handle: AnyWeakModelHandle {
3554                model_id,
3555                model_type: TypeId::of::<T>(),
3556            },
3557            model_type: PhantomData,
3558        }
3559    }
3560
3561    pub fn id(&self) -> usize {
3562        self.model_id
3563    }
3564
3565    pub fn is_upgradable(&self, cx: &impl BorrowAppContext) -> bool {
3566        cx.read_with(|cx| cx.model_handle_is_upgradable(self))
3567    }
3568
3569    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<ModelHandle<T>> {
3570        cx.read_with(|cx| cx.upgrade_model_handle(self))
3571    }
3572}
3573
3574impl<T> Hash for WeakModelHandle<T> {
3575    fn hash<H: Hasher>(&self, state: &mut H) {
3576        self.model_id.hash(state)
3577    }
3578}
3579
3580impl<T> PartialEq for WeakModelHandle<T> {
3581    fn eq(&self, other: &Self) -> bool {
3582        self.model_id == other.model_id
3583    }
3584}
3585
3586impl<T> Eq for WeakModelHandle<T> {}
3587
3588impl<T: Entity> PartialEq<ModelHandle<T>> for WeakModelHandle<T> {
3589    fn eq(&self, other: &ModelHandle<T>) -> bool {
3590        self.model_id == other.model_id
3591    }
3592}
3593
3594impl<T> Clone for WeakModelHandle<T> {
3595    fn clone(&self) -> Self {
3596        Self {
3597            any_handle: self.any_handle.clone(),
3598            model_type: PhantomData,
3599        }
3600    }
3601}
3602
3603impl<T> Copy for WeakModelHandle<T> {}
3604
3605#[repr(transparent)]
3606pub struct ViewHandle<T> {
3607    any_handle: AnyViewHandle,
3608    view_type: PhantomData<T>,
3609}
3610
3611impl<T> Deref for ViewHandle<T> {
3612    type Target = AnyViewHandle;
3613
3614    fn deref(&self) -> &Self::Target {
3615        &self.any_handle
3616    }
3617}
3618
3619impl<T: View> ViewHandle<T> {
3620    fn new(window_id: usize, view_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
3621        Self {
3622            any_handle: AnyViewHandle::new(
3623                window_id,
3624                view_id,
3625                TypeId::of::<T>(),
3626                ref_counts.clone(),
3627            ),
3628            view_type: PhantomData,
3629        }
3630    }
3631
3632    pub fn downgrade(&self) -> WeakViewHandle<T> {
3633        WeakViewHandle::new(self.window_id, self.view_id)
3634    }
3635
3636    pub fn into_any(self) -> AnyViewHandle {
3637        self.any_handle
3638    }
3639
3640    pub fn window_id(&self) -> usize {
3641        self.window_id
3642    }
3643
3644    pub fn id(&self) -> usize {
3645        self.view_id
3646    }
3647
3648    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
3649        cx.read_view(self)
3650    }
3651
3652    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
3653    where
3654        C: BorrowWindowContext,
3655        F: FnOnce(&T, &ViewContext<T>) -> S,
3656    {
3657        cx.read_with(self.window_id, |cx| {
3658            let cx = ViewContext::immutable(cx, self.view_id);
3659            read(cx.read_view(self), &cx)
3660        })
3661    }
3662
3663    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
3664    where
3665        C: BorrowWindowContext,
3666        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
3667    {
3668        let mut update = Some(update);
3669
3670        cx.update(self.window_id, |cx| {
3671            cx.update_view(self, &mut |view, cx| {
3672                let update = update.take().unwrap();
3673                update(view, cx)
3674            })
3675        })
3676    }
3677
3678    pub fn is_focused(&self, cx: &WindowContext) -> bool {
3679        cx.focused_view_id() == Some(self.view_id)
3680    }
3681}
3682
3683impl<T: View> Clone for ViewHandle<T> {
3684    fn clone(&self) -> Self {
3685        ViewHandle::new(self.window_id, self.view_id, &self.ref_counts)
3686    }
3687}
3688
3689impl<T> PartialEq for ViewHandle<T> {
3690    fn eq(&self, other: &Self) -> bool {
3691        self.window_id == other.window_id && self.view_id == other.view_id
3692    }
3693}
3694
3695impl<T> PartialEq<WeakViewHandle<T>> for ViewHandle<T> {
3696    fn eq(&self, other: &WeakViewHandle<T>) -> bool {
3697        self.window_id == other.window_id && self.view_id == other.view_id
3698    }
3699}
3700
3701impl<T> PartialEq<ViewHandle<T>> for WeakViewHandle<T> {
3702    fn eq(&self, other: &ViewHandle<T>) -> bool {
3703        self.window_id == other.window_id && self.view_id == other.view_id
3704    }
3705}
3706
3707impl<T> Eq for ViewHandle<T> {}
3708
3709impl<T> Hash for ViewHandle<T> {
3710    fn hash<H: Hasher>(&self, state: &mut H) {
3711        self.window_id.hash(state);
3712        self.view_id.hash(state);
3713    }
3714}
3715
3716impl<T> Debug for ViewHandle<T> {
3717    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3718        f.debug_struct(&format!("ViewHandle<{}>", type_name::<T>()))
3719            .field("window_id", &self.window_id)
3720            .field("view_id", &self.view_id)
3721            .finish()
3722    }
3723}
3724
3725impl<T: View> Handle<T> for ViewHandle<T> {
3726    type Weak = WeakViewHandle<T>;
3727
3728    fn id(&self) -> usize {
3729        self.view_id
3730    }
3731
3732    fn location(&self) -> EntityLocation {
3733        EntityLocation::View(self.window_id, self.view_id)
3734    }
3735
3736    fn downgrade(&self) -> Self::Weak {
3737        self.downgrade()
3738    }
3739
3740    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
3741    where
3742        Self: Sized,
3743    {
3744        weak.upgrade(cx)
3745    }
3746}
3747
3748pub struct AnyViewHandle {
3749    window_id: usize,
3750    view_id: usize,
3751    view_type: TypeId,
3752    ref_counts: Arc<Mutex<RefCounts>>,
3753
3754    #[cfg(any(test, feature = "test-support"))]
3755    handle_id: usize,
3756}
3757
3758impl AnyViewHandle {
3759    fn new(
3760        window_id: usize,
3761        view_id: usize,
3762        view_type: TypeId,
3763        ref_counts: Arc<Mutex<RefCounts>>,
3764    ) -> Self {
3765        ref_counts.lock().inc_view(window_id, view_id);
3766
3767        #[cfg(any(test, feature = "test-support"))]
3768        let handle_id = ref_counts
3769            .lock()
3770            .leak_detector
3771            .lock()
3772            .handle_created(None, view_id);
3773
3774        Self {
3775            window_id,
3776            view_id,
3777            view_type,
3778            ref_counts,
3779            #[cfg(any(test, feature = "test-support"))]
3780            handle_id,
3781        }
3782    }
3783
3784    pub fn window_id(&self) -> usize {
3785        self.window_id
3786    }
3787
3788    pub fn id(&self) -> usize {
3789        self.view_id
3790    }
3791
3792    pub fn is<T: 'static>(&self) -> bool {
3793        TypeId::of::<T>() == self.view_type
3794    }
3795
3796    pub fn downcast<T: View>(self) -> Option<ViewHandle<T>> {
3797        if self.is::<T>() {
3798            Some(ViewHandle {
3799                any_handle: self,
3800                view_type: PhantomData,
3801            })
3802        } else {
3803            None
3804        }
3805    }
3806
3807    pub fn downcast_ref<T: View>(&self) -> Option<&ViewHandle<T>> {
3808        if self.is::<T>() {
3809            Some(unsafe { mem::transmute(self) })
3810        } else {
3811            None
3812        }
3813    }
3814
3815    pub fn downgrade(&self) -> AnyWeakViewHandle {
3816        AnyWeakViewHandle {
3817            window_id: self.window_id,
3818            view_id: self.view_id,
3819            view_type: self.view_type,
3820        }
3821    }
3822
3823    pub fn view_type(&self) -> TypeId {
3824        self.view_type
3825    }
3826
3827    pub fn debug_json<'a, 'b>(&self, cx: &'b WindowContext<'a>) -> serde_json::Value {
3828        cx.views
3829            .get(&(self.window_id, self.view_id))
3830            .map_or_else(|| serde_json::Value::Null, |view| view.debug_json(cx))
3831    }
3832}
3833
3834impl Clone for AnyViewHandle {
3835    fn clone(&self) -> Self {
3836        Self::new(
3837            self.window_id,
3838            self.view_id,
3839            self.view_type,
3840            self.ref_counts.clone(),
3841        )
3842    }
3843}
3844
3845impl<T> PartialEq<ViewHandle<T>> for AnyViewHandle {
3846    fn eq(&self, other: &ViewHandle<T>) -> bool {
3847        self.window_id == other.window_id && self.view_id == other.view_id
3848    }
3849}
3850
3851impl Drop for AnyViewHandle {
3852    fn drop(&mut self) {
3853        self.ref_counts
3854            .lock()
3855            .dec_view(self.window_id, self.view_id);
3856        #[cfg(any(test, feature = "test-support"))]
3857        self.ref_counts
3858            .lock()
3859            .leak_detector
3860            .lock()
3861            .handle_dropped(self.view_id, self.handle_id);
3862    }
3863}
3864
3865pub struct AnyModelHandle {
3866    model_id: usize,
3867    model_type: TypeId,
3868    ref_counts: Arc<Mutex<RefCounts>>,
3869
3870    #[cfg(any(test, feature = "test-support"))]
3871    handle_id: usize,
3872}
3873
3874impl AnyModelHandle {
3875    fn new(model_id: usize, model_type: TypeId, ref_counts: Arc<Mutex<RefCounts>>) -> Self {
3876        ref_counts.lock().inc_model(model_id);
3877
3878        #[cfg(any(test, feature = "test-support"))]
3879        let handle_id = ref_counts
3880            .lock()
3881            .leak_detector
3882            .lock()
3883            .handle_created(None, model_id);
3884
3885        Self {
3886            model_id,
3887            model_type,
3888            ref_counts,
3889
3890            #[cfg(any(test, feature = "test-support"))]
3891            handle_id,
3892        }
3893    }
3894
3895    pub fn downcast<T: Entity>(self) -> Option<ModelHandle<T>> {
3896        if self.is::<T>() {
3897            Some(ModelHandle {
3898                any_handle: self,
3899                model_type: PhantomData,
3900            })
3901        } else {
3902            None
3903        }
3904    }
3905
3906    pub fn downgrade(&self) -> AnyWeakModelHandle {
3907        AnyWeakModelHandle {
3908            model_id: self.model_id,
3909            model_type: self.model_type,
3910        }
3911    }
3912
3913    pub fn is<T: Entity>(&self) -> bool {
3914        self.model_type == TypeId::of::<T>()
3915    }
3916
3917    pub fn model_type(&self) -> TypeId {
3918        self.model_type
3919    }
3920}
3921
3922impl Clone for AnyModelHandle {
3923    fn clone(&self) -> Self {
3924        Self::new(self.model_id, self.model_type, self.ref_counts.clone())
3925    }
3926}
3927
3928impl Drop for AnyModelHandle {
3929    fn drop(&mut self) {
3930        let mut ref_counts = self.ref_counts.lock();
3931        ref_counts.dec_model(self.model_id);
3932
3933        #[cfg(any(test, feature = "test-support"))]
3934        ref_counts
3935            .leak_detector
3936            .lock()
3937            .handle_dropped(self.model_id, self.handle_id);
3938    }
3939}
3940
3941#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy)]
3942pub struct AnyWeakModelHandle {
3943    model_id: usize,
3944    model_type: TypeId,
3945}
3946
3947impl AnyWeakModelHandle {
3948    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<AnyModelHandle> {
3949        cx.read_with(|cx| cx.upgrade_any_model_handle(self))
3950    }
3951
3952    pub fn model_type(&self) -> TypeId {
3953        self.model_type
3954    }
3955
3956    fn is<T: 'static>(&self) -> bool {
3957        TypeId::of::<T>() == self.model_type
3958    }
3959
3960    pub fn downcast<T: Entity>(self) -> Option<WeakModelHandle<T>> {
3961        if self.is::<T>() {
3962            let result = Some(WeakModelHandle {
3963                any_handle: self,
3964                model_type: PhantomData,
3965            });
3966
3967            result
3968        } else {
3969            None
3970        }
3971    }
3972}
3973
3974#[derive(Debug, Copy)]
3975pub struct WeakViewHandle<T> {
3976    any_handle: AnyWeakViewHandle,
3977    view_type: PhantomData<T>,
3978}
3979
3980impl<T> WeakHandle for WeakViewHandle<T> {
3981    fn id(&self) -> usize {
3982        self.view_id
3983    }
3984}
3985
3986impl<V: View> WeakViewHandle<V> {
3987    fn new(window_id: usize, view_id: usize) -> Self {
3988        Self {
3989            any_handle: AnyWeakViewHandle {
3990                window_id,
3991                view_id,
3992                view_type: TypeId::of::<V>(),
3993            },
3994            view_type: PhantomData,
3995        }
3996    }
3997
3998    pub fn id(&self) -> usize {
3999        self.view_id
4000    }
4001
4002    pub fn window_id(&self) -> usize {
4003        self.window_id
4004    }
4005
4006    pub fn into_any(self) -> AnyWeakViewHandle {
4007        self.any_handle
4008    }
4009
4010    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<ViewHandle<V>> {
4011        cx.read_with(|cx| cx.upgrade_view_handle(self))
4012    }
4013
4014    pub fn read_with<T>(
4015        &self,
4016        cx: &AsyncAppContext,
4017        read: impl FnOnce(&V, &ViewContext<V>) -> T,
4018    ) -> Result<T> {
4019        cx.read(|cx| {
4020            let handle = cx
4021                .upgrade_view_handle(self)
4022                .ok_or_else(|| anyhow!("view {} was dropped", V::ui_name()))?;
4023            cx.read_window(self.window_id, |cx| handle.read_with(cx, read))
4024                .ok_or_else(|| anyhow!("window was removed"))
4025        })
4026    }
4027
4028    pub fn update<T>(
4029        &self,
4030        cx: &mut AsyncAppContext,
4031        update: impl FnOnce(&mut V, &mut ViewContext<V>) -> T,
4032    ) -> Result<T> {
4033        cx.update(|cx| {
4034            let handle = cx
4035                .upgrade_view_handle(self)
4036                .ok_or_else(|| anyhow!("view {} was dropped", V::ui_name()))?;
4037            cx.update_window(self.window_id, |cx| handle.update(cx, update))
4038                .ok_or_else(|| anyhow!("window was removed"))
4039        })
4040    }
4041}
4042
4043impl<T> Deref for WeakViewHandle<T> {
4044    type Target = AnyWeakViewHandle;
4045
4046    fn deref(&self) -> &Self::Target {
4047        &self.any_handle
4048    }
4049}
4050
4051impl<T> Clone for WeakViewHandle<T> {
4052    fn clone(&self) -> Self {
4053        Self {
4054            any_handle: self.any_handle.clone(),
4055            view_type: PhantomData,
4056        }
4057    }
4058}
4059
4060impl<T> PartialEq for WeakViewHandle<T> {
4061    fn eq(&self, other: &Self) -> bool {
4062        self.window_id == other.window_id && self.view_id == other.view_id
4063    }
4064}
4065
4066impl<T> Eq for WeakViewHandle<T> {}
4067
4068impl<T> Hash for WeakViewHandle<T> {
4069    fn hash<H: Hasher>(&self, state: &mut H) {
4070        self.any_handle.hash(state);
4071    }
4072}
4073
4074#[derive(Debug, Clone, Copy)]
4075pub struct AnyWeakViewHandle {
4076    window_id: usize,
4077    view_id: usize,
4078    view_type: TypeId,
4079}
4080
4081impl AnyWeakViewHandle {
4082    pub fn id(&self) -> usize {
4083        self.view_id
4084    }
4085
4086    fn is<T: 'static>(&self) -> bool {
4087        TypeId::of::<T>() == self.view_type
4088    }
4089
4090    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<AnyViewHandle> {
4091        cx.read_with(|cx| cx.upgrade_any_view_handle(self))
4092    }
4093
4094    pub fn downcast<T: View>(self) -> Option<WeakViewHandle<T>> {
4095        if self.is::<T>() {
4096            Some(WeakViewHandle {
4097                any_handle: self,
4098                view_type: PhantomData,
4099            })
4100        } else {
4101            None
4102        }
4103    }
4104}
4105
4106impl Hash for AnyWeakViewHandle {
4107    fn hash<H: Hasher>(&self, state: &mut H) {
4108        self.window_id.hash(state);
4109        self.view_id.hash(state);
4110        self.view_type.hash(state);
4111    }
4112}
4113
4114#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
4115pub struct ElementStateId {
4116    view_id: usize,
4117    element_id: usize,
4118    tag: TypeId,
4119}
4120
4121pub struct ElementStateHandle<T> {
4122    value_type: PhantomData<T>,
4123    id: ElementStateId,
4124    ref_counts: Weak<Mutex<RefCounts>>,
4125}
4126
4127impl<T: 'static> ElementStateHandle<T> {
4128    fn new(id: ElementStateId, frame_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
4129        ref_counts.lock().inc_element_state(id, frame_id);
4130        Self {
4131            value_type: PhantomData,
4132            id,
4133            ref_counts: Arc::downgrade(ref_counts),
4134        }
4135    }
4136
4137    pub fn id(&self) -> ElementStateId {
4138        self.id
4139    }
4140
4141    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
4142        cx.element_states
4143            .get(&self.id)
4144            .unwrap()
4145            .downcast_ref()
4146            .unwrap()
4147    }
4148
4149    pub fn update<C, D, R>(&self, cx: &mut C, f: impl FnOnce(&mut T, &mut C) -> R) -> R
4150    where
4151        C: DerefMut<Target = D>,
4152        D: DerefMut<Target = AppContext>,
4153    {
4154        let mut element_state = cx.deref_mut().element_states.remove(&self.id).unwrap();
4155        let result = f(element_state.downcast_mut().unwrap(), cx);
4156        cx.deref_mut().element_states.insert(self.id, element_state);
4157        result
4158    }
4159}
4160
4161impl<T> Drop for ElementStateHandle<T> {
4162    fn drop(&mut self) {
4163        if let Some(ref_counts) = self.ref_counts.upgrade() {
4164            ref_counts.lock().dec_element_state(self.id);
4165        }
4166    }
4167}
4168
4169#[must_use]
4170pub enum Subscription {
4171    Subscription(callback_collection::Subscription<usize, SubscriptionCallback>),
4172    Observation(callback_collection::Subscription<usize, ObservationCallback>),
4173    GlobalSubscription(callback_collection::Subscription<TypeId, GlobalSubscriptionCallback>),
4174    GlobalObservation(callback_collection::Subscription<TypeId, GlobalObservationCallback>),
4175    FocusObservation(callback_collection::Subscription<usize, FocusObservationCallback>),
4176    WindowActivationObservation(callback_collection::Subscription<usize, WindowActivationCallback>),
4177    WindowFullscreenObservation(callback_collection::Subscription<usize, WindowFullscreenCallback>),
4178    WindowBoundsObservation(callback_collection::Subscription<usize, WindowBoundsCallback>),
4179    KeystrokeObservation(callback_collection::Subscription<usize, KeystrokeCallback>),
4180    ReleaseObservation(callback_collection::Subscription<usize, ReleaseObservationCallback>),
4181    ActionObservation(callback_collection::Subscription<(), ActionObservationCallback>),
4182    ActiveLabeledTasksObservation(
4183        callback_collection::Subscription<(), ActiveLabeledTasksCallback>,
4184    ),
4185}
4186
4187impl Subscription {
4188    pub fn id(&self) -> usize {
4189        match self {
4190            Subscription::Subscription(subscription) => subscription.id(),
4191            Subscription::Observation(subscription) => subscription.id(),
4192            Subscription::GlobalSubscription(subscription) => subscription.id(),
4193            Subscription::GlobalObservation(subscription) => subscription.id(),
4194            Subscription::FocusObservation(subscription) => subscription.id(),
4195            Subscription::WindowActivationObservation(subscription) => subscription.id(),
4196            Subscription::WindowFullscreenObservation(subscription) => subscription.id(),
4197            Subscription::WindowBoundsObservation(subscription) => subscription.id(),
4198            Subscription::KeystrokeObservation(subscription) => subscription.id(),
4199            Subscription::ReleaseObservation(subscription) => subscription.id(),
4200            Subscription::ActionObservation(subscription) => subscription.id(),
4201            Subscription::ActiveLabeledTasksObservation(subscription) => subscription.id(),
4202        }
4203    }
4204
4205    pub fn detach(&mut self) {
4206        match self {
4207            Subscription::Subscription(subscription) => subscription.detach(),
4208            Subscription::GlobalSubscription(subscription) => subscription.detach(),
4209            Subscription::Observation(subscription) => subscription.detach(),
4210            Subscription::GlobalObservation(subscription) => subscription.detach(),
4211            Subscription::FocusObservation(subscription) => subscription.detach(),
4212            Subscription::KeystrokeObservation(subscription) => subscription.detach(),
4213            Subscription::WindowActivationObservation(subscription) => subscription.detach(),
4214            Subscription::WindowFullscreenObservation(subscription) => subscription.detach(),
4215            Subscription::WindowBoundsObservation(subscription) => subscription.detach(),
4216            Subscription::ReleaseObservation(subscription) => subscription.detach(),
4217            Subscription::ActionObservation(subscription) => subscription.detach(),
4218            Subscription::ActiveLabeledTasksObservation(subscription) => subscription.detach(),
4219        }
4220    }
4221}
4222
4223#[cfg(test)]
4224mod tests {
4225    use super::*;
4226    use crate::{
4227        actions,
4228        elements::*,
4229        impl_actions,
4230        platform::{MouseButton, MouseButtonEvent},
4231        window::ChildView,
4232    };
4233    use itertools::Itertools;
4234    use postage::{sink::Sink, stream::Stream};
4235    use serde::Deserialize;
4236    use smol::future::poll_once;
4237    use std::{
4238        cell::Cell,
4239        sync::atomic::{AtomicBool, AtomicUsize, Ordering::SeqCst},
4240    };
4241
4242    #[crate::test(self)]
4243    fn test_model_handles(cx: &mut AppContext) {
4244        struct Model {
4245            other: Option<ModelHandle<Model>>,
4246            events: Vec<String>,
4247        }
4248
4249        impl Entity for Model {
4250            type Event = usize;
4251        }
4252
4253        impl Model {
4254            fn new(other: Option<ModelHandle<Self>>, cx: &mut ModelContext<Self>) -> Self {
4255                if let Some(other) = other.as_ref() {
4256                    cx.observe(other, |me, _, _| {
4257                        me.events.push("notified".into());
4258                    })
4259                    .detach();
4260                    cx.subscribe(other, |me, _, event, _| {
4261                        me.events.push(format!("observed event {}", event));
4262                    })
4263                    .detach();
4264                }
4265
4266                Self {
4267                    other,
4268                    events: Vec::new(),
4269                }
4270            }
4271        }
4272
4273        let handle_1 = cx.add_model(|cx| Model::new(None, cx));
4274        let handle_2 = cx.add_model(|cx| Model::new(Some(handle_1.clone()), cx));
4275        assert_eq!(cx.models.len(), 2);
4276
4277        handle_1.update(cx, |model, cx| {
4278            model.events.push("updated".into());
4279            cx.emit(1);
4280            cx.notify();
4281            cx.emit(2);
4282        });
4283        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
4284        assert_eq!(
4285            handle_2.read(cx).events,
4286            vec![
4287                "observed event 1".to_string(),
4288                "notified".to_string(),
4289                "observed event 2".to_string(),
4290            ]
4291        );
4292
4293        handle_2.update(cx, |model, _| {
4294            drop(handle_1);
4295            model.other.take();
4296        });
4297
4298        assert_eq!(cx.models.len(), 1);
4299        assert!(cx.subscriptions.is_empty());
4300        assert!(cx.observations.is_empty());
4301    }
4302
4303    #[crate::test(self)]
4304    fn test_model_events(cx: &mut AppContext) {
4305        #[derive(Default)]
4306        struct Model {
4307            events: Vec<usize>,
4308        }
4309
4310        impl Entity for Model {
4311            type Event = usize;
4312        }
4313
4314        let handle_1 = cx.add_model(|_| Model::default());
4315        let handle_2 = cx.add_model(|_| Model::default());
4316
4317        handle_1.update(cx, |_, cx| {
4318            cx.subscribe(&handle_2, move |model: &mut Model, emitter, event, cx| {
4319                model.events.push(*event);
4320
4321                cx.subscribe(&emitter, |model, _, event, _| {
4322                    model.events.push(*event * 2);
4323                })
4324                .detach();
4325            })
4326            .detach();
4327        });
4328
4329        handle_2.update(cx, |_, c| c.emit(7));
4330        assert_eq!(handle_1.read(cx).events, vec![7]);
4331
4332        handle_2.update(cx, |_, c| c.emit(5));
4333        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10]);
4334    }
4335
4336    #[crate::test(self)]
4337    fn test_model_emit_before_subscribe_in_same_update_cycle(cx: &mut AppContext) {
4338        #[derive(Default)]
4339        struct Model;
4340
4341        impl Entity for Model {
4342            type Event = ();
4343        }
4344
4345        let events = Rc::new(RefCell::new(Vec::new()));
4346        cx.add_model(|cx| {
4347            drop(cx.subscribe(&cx.handle(), {
4348                let events = events.clone();
4349                move |_, _, _, _| events.borrow_mut().push("dropped before flush")
4350            }));
4351            cx.subscribe(&cx.handle(), {
4352                let events = events.clone();
4353                move |_, _, _, _| events.borrow_mut().push("before emit")
4354            })
4355            .detach();
4356            cx.emit(());
4357            cx.subscribe(&cx.handle(), {
4358                let events = events.clone();
4359                move |_, _, _, _| events.borrow_mut().push("after emit")
4360            })
4361            .detach();
4362            Model
4363        });
4364        assert_eq!(*events.borrow(), ["before emit"]);
4365    }
4366
4367    #[crate::test(self)]
4368    fn test_observe_and_notify_from_model(cx: &mut AppContext) {
4369        #[derive(Default)]
4370        struct Model {
4371            count: usize,
4372            events: Vec<usize>,
4373        }
4374
4375        impl Entity for Model {
4376            type Event = ();
4377        }
4378
4379        let handle_1 = cx.add_model(|_| Model::default());
4380        let handle_2 = cx.add_model(|_| Model::default());
4381
4382        handle_1.update(cx, |_, c| {
4383            c.observe(&handle_2, move |model, observed, c| {
4384                model.events.push(observed.read(c).count);
4385                c.observe(&observed, |model, observed, c| {
4386                    model.events.push(observed.read(c).count * 2);
4387                })
4388                .detach();
4389            })
4390            .detach();
4391        });
4392
4393        handle_2.update(cx, |model, c| {
4394            model.count = 7;
4395            c.notify()
4396        });
4397        assert_eq!(handle_1.read(cx).events, vec![7]);
4398
4399        handle_2.update(cx, |model, c| {
4400            model.count = 5;
4401            c.notify()
4402        });
4403        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10])
4404    }
4405
4406    #[crate::test(self)]
4407    fn test_model_notify_before_observe_in_same_update_cycle(cx: &mut AppContext) {
4408        #[derive(Default)]
4409        struct Model;
4410
4411        impl Entity for Model {
4412            type Event = ();
4413        }
4414
4415        let events = Rc::new(RefCell::new(Vec::new()));
4416        cx.add_model(|cx| {
4417            drop(cx.observe(&cx.handle(), {
4418                let events = events.clone();
4419                move |_, _, _| events.borrow_mut().push("dropped before flush")
4420            }));
4421            cx.observe(&cx.handle(), {
4422                let events = events.clone();
4423                move |_, _, _| events.borrow_mut().push("before notify")
4424            })
4425            .detach();
4426            cx.notify();
4427            cx.observe(&cx.handle(), {
4428                let events = events.clone();
4429                move |_, _, _| events.borrow_mut().push("after notify")
4430            })
4431            .detach();
4432            Model
4433        });
4434        assert_eq!(*events.borrow(), ["before notify"]);
4435    }
4436
4437    #[crate::test(self)]
4438    fn test_defer_and_after_window_update(cx: &mut TestAppContext) {
4439        struct View {
4440            render_count: usize,
4441        }
4442
4443        impl Entity for View {
4444            type Event = usize;
4445        }
4446
4447        impl super::View for View {
4448            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
4449                post_inc(&mut self.render_count);
4450                Empty::new().into_any()
4451            }
4452
4453            fn ui_name() -> &'static str {
4454                "View"
4455            }
4456        }
4457
4458        let (_, view) = cx.add_window(|_| View { render_count: 0 });
4459        let called_defer = Rc::new(AtomicBool::new(false));
4460        let called_after_window_update = Rc::new(AtomicBool::new(false));
4461
4462        view.update(cx, |this, cx| {
4463            assert_eq!(this.render_count, 1);
4464            cx.defer({
4465                let called_defer = called_defer.clone();
4466                move |this, _| {
4467                    assert_eq!(this.render_count, 1);
4468                    called_defer.store(true, SeqCst);
4469                }
4470            });
4471            cx.after_window_update({
4472                let called_after_window_update = called_after_window_update.clone();
4473                move |this, cx| {
4474                    assert_eq!(this.render_count, 2);
4475                    called_after_window_update.store(true, SeqCst);
4476                    cx.notify();
4477                }
4478            });
4479            assert!(!called_defer.load(SeqCst));
4480            assert!(!called_after_window_update.load(SeqCst));
4481            cx.notify();
4482        });
4483
4484        assert!(called_defer.load(SeqCst));
4485        assert!(called_after_window_update.load(SeqCst));
4486        assert_eq!(view.read_with(cx, |view, _| view.render_count), 3);
4487    }
4488
4489    #[crate::test(self)]
4490    fn test_view_handles(cx: &mut TestAppContext) {
4491        struct View {
4492            other: Option<ViewHandle<View>>,
4493            events: Vec<String>,
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                Empty::new().into_any()
4503            }
4504
4505            fn ui_name() -> &'static str {
4506                "View"
4507            }
4508        }
4509
4510        impl View {
4511            fn new(other: Option<ViewHandle<View>>, cx: &mut ViewContext<Self>) -> Self {
4512                if let Some(other) = other.as_ref() {
4513                    cx.subscribe(other, |me, _, event, _| {
4514                        me.events.push(format!("observed event {}", event));
4515                    })
4516                    .detach();
4517                }
4518                Self {
4519                    other,
4520                    events: Vec::new(),
4521                }
4522            }
4523        }
4524
4525        let (window_id, _root_view) = cx.add_window(|cx| View::new(None, cx));
4526        let handle_1 = cx.add_view(window_id, |cx| View::new(None, cx));
4527        let handle_2 = cx.add_view(window_id, |cx| View::new(Some(handle_1.clone()), cx));
4528        assert_eq!(cx.read(|cx| cx.views.len()), 3);
4529
4530        handle_1.update(cx, |view, cx| {
4531            view.events.push("updated".into());
4532            cx.emit(1);
4533            cx.emit(2);
4534        });
4535        handle_1.read_with(cx, |view, _| {
4536            assert_eq!(view.events, vec!["updated".to_string()]);
4537        });
4538        handle_2.read_with(cx, |view, _| {
4539            assert_eq!(
4540                view.events,
4541                vec![
4542                    "observed event 1".to_string(),
4543                    "observed event 2".to_string(),
4544                ]
4545            );
4546        });
4547
4548        handle_2.update(cx, |view, _| {
4549            drop(handle_1);
4550            view.other.take();
4551        });
4552
4553        cx.read(|cx| {
4554            assert_eq!(cx.views.len(), 2);
4555            assert!(cx.subscriptions.is_empty());
4556            assert!(cx.observations.is_empty());
4557        });
4558    }
4559
4560    #[crate::test(self)]
4561    fn test_add_window(cx: &mut AppContext) {
4562        struct View {
4563            mouse_down_count: Arc<AtomicUsize>,
4564        }
4565
4566        impl Entity for View {
4567            type Event = ();
4568        }
4569
4570        impl super::View for View {
4571            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
4572                enum Handler {}
4573                let mouse_down_count = self.mouse_down_count.clone();
4574                MouseEventHandler::<Handler, _>::new(0, cx, |_, _| Empty::new())
4575                    .on_down(MouseButton::Left, move |_, _, _| {
4576                        mouse_down_count.fetch_add(1, SeqCst);
4577                    })
4578                    .into_any()
4579            }
4580
4581            fn ui_name() -> &'static str {
4582                "View"
4583            }
4584        }
4585
4586        let mouse_down_count = Arc::new(AtomicUsize::new(0));
4587        let (window_id, _) = cx.add_window(Default::default(), |_| View {
4588            mouse_down_count: mouse_down_count.clone(),
4589        });
4590
4591        cx.update_window(window_id, |cx| {
4592            // Ensure window's root element is in a valid lifecycle state.
4593            cx.dispatch_event(
4594                Event::MouseDown(MouseButtonEvent {
4595                    position: Default::default(),
4596                    button: MouseButton::Left,
4597                    modifiers: Default::default(),
4598                    click_count: 1,
4599                }),
4600                false,
4601            );
4602            assert_eq!(mouse_down_count.load(SeqCst), 1);
4603        });
4604    }
4605
4606    #[crate::test(self)]
4607    fn test_entity_release_hooks(cx: &mut AppContext) {
4608        struct Model {
4609            released: Rc<Cell<bool>>,
4610        }
4611
4612        struct View {
4613            released: Rc<Cell<bool>>,
4614        }
4615
4616        impl Entity for Model {
4617            type Event = ();
4618
4619            fn release(&mut self, _: &mut AppContext) {
4620                self.released.set(true);
4621            }
4622        }
4623
4624        impl Entity for View {
4625            type Event = ();
4626
4627            fn release(&mut self, _: &mut AppContext) {
4628                self.released.set(true);
4629            }
4630        }
4631
4632        impl super::View for View {
4633            fn ui_name() -> &'static str {
4634                "View"
4635            }
4636
4637            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
4638                Empty::new().into_any()
4639            }
4640        }
4641
4642        let model_released = Rc::new(Cell::new(false));
4643        let model_release_observed = Rc::new(Cell::new(false));
4644        let view_released = Rc::new(Cell::new(false));
4645        let view_release_observed = Rc::new(Cell::new(false));
4646
4647        let model = cx.add_model(|_| Model {
4648            released: model_released.clone(),
4649        });
4650        let (window_id, view) = cx.add_window(Default::default(), |_| View {
4651            released: view_released.clone(),
4652        });
4653        assert!(!model_released.get());
4654        assert!(!view_released.get());
4655
4656        cx.observe_release(&model, {
4657            let model_release_observed = model_release_observed.clone();
4658            move |_, _| model_release_observed.set(true)
4659        })
4660        .detach();
4661        cx.observe_release(&view, {
4662            let view_release_observed = view_release_observed.clone();
4663            move |_, _| view_release_observed.set(true)
4664        })
4665        .detach();
4666
4667        cx.update(move |_| {
4668            drop(model);
4669        });
4670        assert!(model_released.get());
4671        assert!(model_release_observed.get());
4672
4673        drop(view);
4674        cx.update_window(window_id, |cx| cx.remove_window());
4675        assert!(view_released.get());
4676        assert!(view_release_observed.get());
4677    }
4678
4679    #[crate::test(self)]
4680    fn test_view_events(cx: &mut TestAppContext) {
4681        struct Model;
4682
4683        impl Entity for Model {
4684            type Event = String;
4685        }
4686
4687        let (window_id, handle_1) = cx.add_window(|_| TestView::default());
4688        let handle_2 = cx.add_view(window_id, |_| TestView::default());
4689        let handle_3 = cx.add_model(|_| Model);
4690
4691        handle_1.update(cx, |_, cx| {
4692            cx.subscribe(&handle_2, move |me, emitter, event, cx| {
4693                me.events.push(event.clone());
4694
4695                cx.subscribe(&emitter, |me, _, event, _| {
4696                    me.events.push(format!("{event} from inner"));
4697                })
4698                .detach();
4699            })
4700            .detach();
4701
4702            cx.subscribe(&handle_3, |me, _, event, _| {
4703                me.events.push(event.clone());
4704            })
4705            .detach();
4706        });
4707
4708        handle_2.update(cx, |_, c| c.emit("7".into()));
4709        handle_1.read_with(cx, |view, _| assert_eq!(view.events, ["7"]));
4710
4711        handle_2.update(cx, |_, c| c.emit("5".into()));
4712        handle_1.read_with(cx, |view, _| {
4713            assert_eq!(view.events, ["7", "5", "5 from inner"])
4714        });
4715
4716        handle_3.update(cx, |_, c| c.emit("9".into()));
4717        handle_1.read_with(cx, |view, _| {
4718            assert_eq!(view.events, ["7", "5", "5 from inner", "9"])
4719        });
4720    }
4721
4722    #[crate::test(self)]
4723    fn test_global_events(cx: &mut AppContext) {
4724        #[derive(Clone, Debug, Eq, PartialEq)]
4725        struct GlobalEvent(u64);
4726
4727        let events = Rc::new(RefCell::new(Vec::new()));
4728        let first_subscription;
4729        let second_subscription;
4730
4731        {
4732            let events = events.clone();
4733            first_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
4734                events.borrow_mut().push(("First", e.clone()));
4735            });
4736        }
4737
4738        {
4739            let events = events.clone();
4740            second_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
4741                events.borrow_mut().push(("Second", e.clone()));
4742            });
4743        }
4744
4745        cx.update(|cx| {
4746            cx.emit_global(GlobalEvent(1));
4747            cx.emit_global(GlobalEvent(2));
4748        });
4749
4750        drop(first_subscription);
4751
4752        cx.update(|cx| {
4753            cx.emit_global(GlobalEvent(3));
4754        });
4755
4756        drop(second_subscription);
4757
4758        cx.update(|cx| {
4759            cx.emit_global(GlobalEvent(4));
4760        });
4761
4762        assert_eq!(
4763            &*events.borrow(),
4764            &[
4765                ("First", GlobalEvent(1)),
4766                ("Second", GlobalEvent(1)),
4767                ("First", GlobalEvent(2)),
4768                ("Second", GlobalEvent(2)),
4769                ("Second", GlobalEvent(3)),
4770            ]
4771        );
4772    }
4773
4774    #[crate::test(self)]
4775    fn test_global_events_emitted_before_subscription_in_same_update_cycle(cx: &mut AppContext) {
4776        let events = Rc::new(RefCell::new(Vec::new()));
4777        cx.update(|cx| {
4778            {
4779                let events = events.clone();
4780                drop(cx.subscribe_global(move |_: &(), _| {
4781                    events.borrow_mut().push("dropped before emit");
4782                }));
4783            }
4784
4785            {
4786                let events = events.clone();
4787                cx.subscribe_global(move |_: &(), _| {
4788                    events.borrow_mut().push("before emit");
4789                })
4790                .detach();
4791            }
4792
4793            cx.emit_global(());
4794
4795            {
4796                let events = events.clone();
4797                cx.subscribe_global(move |_: &(), _| {
4798                    events.borrow_mut().push("after emit");
4799                })
4800                .detach();
4801            }
4802        });
4803
4804        assert_eq!(*events.borrow(), ["before emit"]);
4805    }
4806
4807    #[crate::test(self)]
4808    fn test_global_nested_events(cx: &mut AppContext) {
4809        #[derive(Clone, Debug, Eq, PartialEq)]
4810        struct GlobalEvent(u64);
4811
4812        let events = Rc::new(RefCell::new(Vec::new()));
4813
4814        {
4815            let events = events.clone();
4816            cx.subscribe_global(move |e: &GlobalEvent, cx| {
4817                events.borrow_mut().push(("Outer", e.clone()));
4818
4819                if e.0 == 1 {
4820                    let events = events.clone();
4821                    cx.subscribe_global(move |e: &GlobalEvent, _| {
4822                        events.borrow_mut().push(("Inner", e.clone()));
4823                    })
4824                    .detach();
4825                }
4826            })
4827            .detach();
4828        }
4829
4830        cx.update(|cx| {
4831            cx.emit_global(GlobalEvent(1));
4832            cx.emit_global(GlobalEvent(2));
4833            cx.emit_global(GlobalEvent(3));
4834        });
4835        cx.update(|cx| {
4836            cx.emit_global(GlobalEvent(4));
4837        });
4838
4839        assert_eq!(
4840            &*events.borrow(),
4841            &[
4842                ("Outer", GlobalEvent(1)),
4843                ("Outer", GlobalEvent(2)),
4844                ("Outer", GlobalEvent(3)),
4845                ("Outer", GlobalEvent(4)),
4846                ("Inner", GlobalEvent(4)),
4847            ]
4848        );
4849    }
4850
4851    #[crate::test(self)]
4852    fn test_global(cx: &mut AppContext) {
4853        type Global = usize;
4854
4855        let observation_count = Rc::new(RefCell::new(0));
4856        let subscription = cx.observe_global::<Global, _>({
4857            let observation_count = observation_count.clone();
4858            move |_| {
4859                *observation_count.borrow_mut() += 1;
4860            }
4861        });
4862
4863        assert!(!cx.has_global::<Global>());
4864        assert_eq!(cx.default_global::<Global>(), &0);
4865        assert_eq!(*observation_count.borrow(), 1);
4866        assert!(cx.has_global::<Global>());
4867        assert_eq!(
4868            cx.update_global::<Global, _, _>(|global, _| {
4869                *global = 1;
4870                "Update Result"
4871            }),
4872            "Update Result"
4873        );
4874        assert_eq!(*observation_count.borrow(), 2);
4875        assert_eq!(cx.global::<Global>(), &1);
4876
4877        drop(subscription);
4878        cx.update_global::<Global, _, _>(|global, _| {
4879            *global = 2;
4880        });
4881        assert_eq!(*observation_count.borrow(), 2);
4882
4883        type OtherGlobal = f32;
4884
4885        let observation_count = Rc::new(RefCell::new(0));
4886        cx.observe_global::<OtherGlobal, _>({
4887            let observation_count = observation_count.clone();
4888            move |_| {
4889                *observation_count.borrow_mut() += 1;
4890            }
4891        })
4892        .detach();
4893
4894        assert_eq!(
4895            cx.update_default_global::<OtherGlobal, _, _>(|global, _| {
4896                assert_eq!(global, &0.0);
4897                *global = 2.0;
4898                "Default update result"
4899            }),
4900            "Default update result"
4901        );
4902        assert_eq!(cx.global::<OtherGlobal>(), &2.0);
4903        assert_eq!(*observation_count.borrow(), 1);
4904    }
4905
4906    #[crate::test(self)]
4907    fn test_dropping_subscribers(cx: &mut TestAppContext) {
4908        struct Model;
4909
4910        impl Entity for Model {
4911            type Event = ();
4912        }
4913
4914        let (window_id, _root_view) = cx.add_window(|_| TestView::default());
4915        let observing_view = cx.add_view(window_id, |_| TestView::default());
4916        let emitting_view = cx.add_view(window_id, |_| TestView::default());
4917        let observing_model = cx.add_model(|_| Model);
4918        let observed_model = cx.add_model(|_| Model);
4919
4920        observing_view.update(cx, |_, cx| {
4921            cx.subscribe(&emitting_view, |_, _, _, _| {}).detach();
4922            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
4923        });
4924        observing_model.update(cx, |_, cx| {
4925            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
4926        });
4927
4928        cx.update(|_| {
4929            drop(observing_view);
4930            drop(observing_model);
4931        });
4932
4933        emitting_view.update(cx, |_, cx| cx.emit(Default::default()));
4934        observed_model.update(cx, |_, cx| cx.emit(()));
4935    }
4936
4937    #[crate::test(self)]
4938    fn test_view_emit_before_subscribe_in_same_update_cycle(cx: &mut AppContext) {
4939        let (_, view) = cx.add_window::<TestView, _>(Default::default(), |cx| {
4940            drop(cx.subscribe(&cx.handle(), {
4941                move |this, _, _, _| this.events.push("dropped before flush".into())
4942            }));
4943            cx.subscribe(&cx.handle(), {
4944                move |this, _, _, _| this.events.push("before emit".into())
4945            })
4946            .detach();
4947            cx.emit("the event".into());
4948            cx.subscribe(&cx.handle(), {
4949                move |this, _, _, _| this.events.push("after emit".into())
4950            })
4951            .detach();
4952            TestView { events: Vec::new() }
4953        });
4954
4955        assert_eq!(view.read(cx).events, ["before emit"]);
4956    }
4957
4958    #[crate::test(self)]
4959    fn test_observe_and_notify_from_view(cx: &mut TestAppContext) {
4960        #[derive(Default)]
4961        struct Model {
4962            state: String,
4963        }
4964
4965        impl Entity for Model {
4966            type Event = ();
4967        }
4968
4969        let (_, view) = cx.add_window(|_| TestView::default());
4970        let model = cx.add_model(|_| Model {
4971            state: "old-state".into(),
4972        });
4973
4974        view.update(cx, |_, c| {
4975            c.observe(&model, |me, observed, cx| {
4976                me.events.push(observed.read(cx).state.clone())
4977            })
4978            .detach();
4979        });
4980
4981        model.update(cx, |model, cx| {
4982            model.state = "new-state".into();
4983            cx.notify();
4984        });
4985        view.read_with(cx, |view, _| assert_eq!(view.events, ["new-state"]));
4986    }
4987
4988    #[crate::test(self)]
4989    fn test_view_notify_before_observe_in_same_update_cycle(cx: &mut AppContext) {
4990        let (_, view) = cx.add_window::<TestView, _>(Default::default(), |cx| {
4991            drop(cx.observe(&cx.handle(), {
4992                move |this, _, _| this.events.push("dropped before flush".into())
4993            }));
4994            cx.observe(&cx.handle(), {
4995                move |this, _, _| this.events.push("before notify".into())
4996            })
4997            .detach();
4998            cx.notify();
4999            cx.observe(&cx.handle(), {
5000                move |this, _, _| this.events.push("after notify".into())
5001            })
5002            .detach();
5003            TestView { events: Vec::new() }
5004        });
5005
5006        assert_eq!(view.read(cx).events, ["before notify"]);
5007    }
5008
5009    #[crate::test(self)]
5010    fn test_notify_and_drop_observe_subscription_in_same_update_cycle(cx: &mut TestAppContext) {
5011        struct Model;
5012        impl Entity for Model {
5013            type Event = ();
5014        }
5015
5016        let model = cx.add_model(|_| Model);
5017        let (_, view) = cx.add_window(|_| TestView::default());
5018
5019        view.update(cx, |_, cx| {
5020            model.update(cx, |_, cx| cx.notify());
5021            drop(cx.observe(&model, move |this, _, _| {
5022                this.events.push("model notified".into());
5023            }));
5024            model.update(cx, |_, cx| cx.notify());
5025        });
5026
5027        for _ in 0..3 {
5028            model.update(cx, |_, cx| cx.notify());
5029        }
5030        view.read_with(cx, |view, _| assert_eq!(view.events, Vec::<&str>::new()));
5031    }
5032
5033    #[crate::test(self)]
5034    fn test_dropping_observers(cx: &mut TestAppContext) {
5035        struct Model;
5036
5037        impl Entity for Model {
5038            type Event = ();
5039        }
5040
5041        let (window_id, _root_view) = cx.add_window(|_| TestView::default());
5042        let observing_view = cx.add_view(window_id, |_| TestView::default());
5043        let observing_model = cx.add_model(|_| Model);
5044        let observed_model = cx.add_model(|_| Model);
5045
5046        observing_view.update(cx, |_, cx| {
5047            cx.observe(&observed_model, |_, _, _| {}).detach();
5048        });
5049        observing_model.update(cx, |_, cx| {
5050            cx.observe(&observed_model, |_, _, _| {}).detach();
5051        });
5052
5053        cx.update(|_| {
5054            drop(observing_view);
5055            drop(observing_model);
5056        });
5057
5058        observed_model.update(cx, |_, cx| cx.notify());
5059    }
5060
5061    #[crate::test(self)]
5062    fn test_dropping_subscriptions_during_callback(cx: &mut TestAppContext) {
5063        struct Model;
5064
5065        impl Entity for Model {
5066            type Event = u64;
5067        }
5068
5069        // Events
5070        let observing_model = cx.add_model(|_| Model);
5071        let observed_model = cx.add_model(|_| Model);
5072
5073        let events = Rc::new(RefCell::new(Vec::new()));
5074
5075        observing_model.update(cx, |_, cx| {
5076            let events = events.clone();
5077            let subscription = Rc::new(RefCell::new(None));
5078            *subscription.borrow_mut() = Some(cx.subscribe(&observed_model, {
5079                let subscription = subscription.clone();
5080                move |_, _, e, _| {
5081                    subscription.borrow_mut().take();
5082                    events.borrow_mut().push(*e);
5083                }
5084            }));
5085        });
5086
5087        observed_model.update(cx, |_, cx| {
5088            cx.emit(1);
5089            cx.emit(2);
5090        });
5091
5092        assert_eq!(*events.borrow(), [1]);
5093
5094        // Global Events
5095        #[derive(Clone, Debug, Eq, PartialEq)]
5096        struct GlobalEvent(u64);
5097
5098        let events = Rc::new(RefCell::new(Vec::new()));
5099
5100        {
5101            let events = events.clone();
5102            let subscription = Rc::new(RefCell::new(None));
5103            *subscription.borrow_mut() = Some(cx.subscribe_global({
5104                let subscription = subscription.clone();
5105                move |e: &GlobalEvent, _| {
5106                    subscription.borrow_mut().take();
5107                    events.borrow_mut().push(e.clone());
5108                }
5109            }));
5110        }
5111
5112        cx.update(|cx| {
5113            cx.emit_global(GlobalEvent(1));
5114            cx.emit_global(GlobalEvent(2));
5115        });
5116
5117        assert_eq!(*events.borrow(), [GlobalEvent(1)]);
5118
5119        // Model Observation
5120        let observing_model = cx.add_model(|_| Model);
5121        let observed_model = cx.add_model(|_| Model);
5122
5123        let observation_count = Rc::new(RefCell::new(0));
5124
5125        observing_model.update(cx, |_, cx| {
5126            let observation_count = observation_count.clone();
5127            let subscription = Rc::new(RefCell::new(None));
5128            *subscription.borrow_mut() = Some(cx.observe(&observed_model, {
5129                let subscription = subscription.clone();
5130                move |_, _, _| {
5131                    subscription.borrow_mut().take();
5132                    *observation_count.borrow_mut() += 1;
5133                }
5134            }));
5135        });
5136
5137        observed_model.update(cx, |_, cx| {
5138            cx.notify();
5139        });
5140
5141        observed_model.update(cx, |_, cx| {
5142            cx.notify();
5143        });
5144
5145        assert_eq!(*observation_count.borrow(), 1);
5146
5147        // View Observation
5148        struct View;
5149
5150        impl Entity for View {
5151            type Event = ();
5152        }
5153
5154        impl super::View for View {
5155            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
5156                Empty::new().into_any()
5157            }
5158
5159            fn ui_name() -> &'static str {
5160                "View"
5161            }
5162        }
5163
5164        let (window_id, _root_view) = cx.add_window(|_| View);
5165        let observing_view = cx.add_view(window_id, |_| View);
5166        let observed_view = cx.add_view(window_id, |_| View);
5167
5168        let observation_count = Rc::new(RefCell::new(0));
5169        observing_view.update(cx, |_, cx| {
5170            let observation_count = observation_count.clone();
5171            let subscription = Rc::new(RefCell::new(None));
5172            *subscription.borrow_mut() = Some(cx.observe(&observed_view, {
5173                let subscription = subscription.clone();
5174                move |_, _, _| {
5175                    subscription.borrow_mut().take();
5176                    *observation_count.borrow_mut() += 1;
5177                }
5178            }));
5179        });
5180
5181        observed_view.update(cx, |_, cx| {
5182            cx.notify();
5183        });
5184
5185        observed_view.update(cx, |_, cx| {
5186            cx.notify();
5187        });
5188
5189        assert_eq!(*observation_count.borrow(), 1);
5190
5191        // Global Observation
5192        let observation_count = Rc::new(RefCell::new(0));
5193        let subscription = Rc::new(RefCell::new(None));
5194        *subscription.borrow_mut() = Some(cx.observe_global::<(), _>({
5195            let observation_count = observation_count.clone();
5196            let subscription = subscription.clone();
5197            move |_| {
5198                subscription.borrow_mut().take();
5199                *observation_count.borrow_mut() += 1;
5200            }
5201        }));
5202
5203        cx.update(|cx| {
5204            cx.default_global::<()>();
5205            cx.set_global(());
5206        });
5207        assert_eq!(*observation_count.borrow(), 1);
5208    }
5209
5210    #[crate::test(self)]
5211    fn test_focus(cx: &mut TestAppContext) {
5212        struct View {
5213            name: String,
5214            events: Arc<Mutex<Vec<String>>>,
5215            child: Option<AnyViewHandle>,
5216        }
5217
5218        impl Entity for View {
5219            type Event = ();
5220        }
5221
5222        impl super::View for View {
5223            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5224                self.child
5225                    .as_ref()
5226                    .map(|child| ChildView::new(child, cx).into_any())
5227                    .unwrap_or(Empty::new().into_any())
5228            }
5229
5230            fn ui_name() -> &'static str {
5231                "View"
5232            }
5233
5234            fn focus_in(&mut self, focused: AnyViewHandle, cx: &mut ViewContext<Self>) {
5235                if cx.handle().id() == focused.id() {
5236                    self.events.lock().push(format!("{} focused", &self.name));
5237                }
5238            }
5239
5240            fn focus_out(&mut self, blurred: AnyViewHandle, cx: &mut ViewContext<Self>) {
5241                if cx.handle().id() == blurred.id() {
5242                    self.events.lock().push(format!("{} blurred", &self.name));
5243                }
5244            }
5245        }
5246
5247        let view_events: Arc<Mutex<Vec<String>>> = Default::default();
5248        let (window_id, view_1) = cx.add_window(|_| View {
5249            events: view_events.clone(),
5250            name: "view 1".to_string(),
5251            child: None,
5252        });
5253        let view_2 = cx
5254            .update_window(window_id, |cx| {
5255                let view_2 = cx.add_view(|_| View {
5256                    events: view_events.clone(),
5257                    name: "view 2".to_string(),
5258                    child: None,
5259                });
5260                view_1.update(cx, |view_1, cx| {
5261                    view_1.child = Some(view_2.clone().into_any());
5262                    cx.notify();
5263                });
5264                view_2
5265            })
5266            .unwrap();
5267
5268        let observed_events: Arc<Mutex<Vec<String>>> = Default::default();
5269        view_1.update(cx, |_, cx| {
5270            cx.observe_focus(&view_2, {
5271                let observed_events = observed_events.clone();
5272                move |this, view, focused, cx| {
5273                    let label = if focused { "focus" } else { "blur" };
5274                    observed_events.lock().push(format!(
5275                        "{} observed {}'s {}",
5276                        this.name,
5277                        view.read(cx).name,
5278                        label
5279                    ))
5280                }
5281            })
5282            .detach();
5283        });
5284        view_2.update(cx, |_, cx| {
5285            cx.observe_focus(&view_1, {
5286                let observed_events = observed_events.clone();
5287                move |this, view, focused, cx| {
5288                    let label = if focused { "focus" } else { "blur" };
5289                    observed_events.lock().push(format!(
5290                        "{} observed {}'s {}",
5291                        this.name,
5292                        view.read(cx).name,
5293                        label
5294                    ))
5295                }
5296            })
5297            .detach();
5298        });
5299        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
5300        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
5301
5302        view_1.update(cx, |_, cx| {
5303            // Ensure only the last focus event is honored.
5304            cx.focus(&view_2);
5305            cx.focus(&view_1);
5306            cx.focus(&view_2);
5307        });
5308
5309        cx.read_window(window_id, |cx| {
5310            assert!(cx.is_child_focused(&view_1));
5311            assert!(!cx.is_child_focused(&view_2));
5312        });
5313        assert_eq!(
5314            mem::take(&mut *view_events.lock()),
5315            ["view 1 blurred", "view 2 focused"],
5316        );
5317        assert_eq!(
5318            mem::take(&mut *observed_events.lock()),
5319            [
5320                "view 2 observed view 1's blur",
5321                "view 1 observed view 2's focus"
5322            ]
5323        );
5324
5325        view_1.update(cx, |_, cx| cx.focus(&view_1));
5326        cx.read_window(window_id, |cx| {
5327            assert!(!cx.is_child_focused(&view_1));
5328            assert!(!cx.is_child_focused(&view_2));
5329        });
5330        assert_eq!(
5331            mem::take(&mut *view_events.lock()),
5332            ["view 2 blurred", "view 1 focused"],
5333        );
5334        assert_eq!(
5335            mem::take(&mut *observed_events.lock()),
5336            [
5337                "view 1 observed view 2's blur",
5338                "view 2 observed view 1's focus"
5339            ]
5340        );
5341
5342        view_1.update(cx, |_, cx| cx.focus(&view_2));
5343        assert_eq!(
5344            mem::take(&mut *view_events.lock()),
5345            ["view 1 blurred", "view 2 focused"],
5346        );
5347        assert_eq!(
5348            mem::take(&mut *observed_events.lock()),
5349            [
5350                "view 2 observed view 1's blur",
5351                "view 1 observed view 2's focus"
5352            ]
5353        );
5354
5355        println!("=====================");
5356        view_1.update(cx, |view, _| {
5357            drop(view_2);
5358            view.child = None;
5359        });
5360        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
5361        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
5362    }
5363
5364    #[crate::test(self)]
5365    fn test_deserialize_actions(cx: &mut AppContext) {
5366        #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
5367        pub struct ComplexAction {
5368            arg: String,
5369            count: usize,
5370        }
5371
5372        actions!(test::something, [SimpleAction]);
5373        impl_actions!(test::something, [ComplexAction]);
5374
5375        cx.add_global_action(move |_: &SimpleAction, _: &mut AppContext| {});
5376        cx.add_global_action(move |_: &ComplexAction, _: &mut AppContext| {});
5377
5378        let action1 = cx
5379            .deserialize_action(
5380                "test::something::ComplexAction",
5381                Some(r#"{"arg": "a", "count": 5}"#),
5382            )
5383            .unwrap();
5384        let action2 = cx
5385            .deserialize_action("test::something::SimpleAction", None)
5386            .unwrap();
5387        assert_eq!(
5388            action1.as_any().downcast_ref::<ComplexAction>().unwrap(),
5389            &ComplexAction {
5390                arg: "a".to_string(),
5391                count: 5,
5392            }
5393        );
5394        assert_eq!(
5395            action2.as_any().downcast_ref::<SimpleAction>().unwrap(),
5396            &SimpleAction
5397        );
5398    }
5399
5400    #[crate::test(self)]
5401    fn test_dispatch_action(cx: &mut AppContext) {
5402        struct ViewA {
5403            id: usize,
5404            child: Option<AnyViewHandle>,
5405        }
5406
5407        impl Entity for ViewA {
5408            type Event = ();
5409        }
5410
5411        impl View for ViewA {
5412            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5413                self.child
5414                    .as_ref()
5415                    .map(|child| ChildView::new(child, cx).into_any())
5416                    .unwrap_or(Empty::new().into_any())
5417            }
5418
5419            fn ui_name() -> &'static str {
5420                "View"
5421            }
5422        }
5423
5424        struct ViewB {
5425            id: usize,
5426            child: Option<AnyViewHandle>,
5427        }
5428
5429        impl Entity for ViewB {
5430            type Event = ();
5431        }
5432
5433        impl View for ViewB {
5434            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5435                self.child
5436                    .as_ref()
5437                    .map(|child| ChildView::new(child, cx).into_any())
5438                    .unwrap_or(Empty::new().into_any())
5439            }
5440
5441            fn ui_name() -> &'static str {
5442                "View"
5443            }
5444        }
5445
5446        #[derive(Clone, Default, Deserialize, PartialEq)]
5447        pub struct Action(pub String);
5448
5449        impl_actions!(test, [Action]);
5450
5451        let actions = Rc::new(RefCell::new(Vec::new()));
5452
5453        cx.add_global_action({
5454            let actions = actions.clone();
5455            move |_: &Action, _: &mut AppContext| {
5456                actions.borrow_mut().push("global".to_string());
5457            }
5458        });
5459
5460        cx.add_action({
5461            let actions = actions.clone();
5462            move |view: &mut ViewA, action: &Action, cx| {
5463                assert_eq!(action.0, "bar");
5464                cx.propagate_action();
5465                actions.borrow_mut().push(format!("{} a", view.id));
5466            }
5467        });
5468
5469        cx.add_action({
5470            let actions = actions.clone();
5471            move |view: &mut ViewA, _: &Action, cx| {
5472                if view.id != 1 {
5473                    cx.add_view(|cx| {
5474                        cx.propagate_action(); // Still works on a nested ViewContext
5475                        ViewB { id: 5, child: None }
5476                    });
5477                }
5478                actions.borrow_mut().push(format!("{} b", view.id));
5479            }
5480        });
5481
5482        cx.add_action({
5483            let actions = actions.clone();
5484            move |view: &mut ViewB, _: &Action, cx| {
5485                cx.propagate_action();
5486                actions.borrow_mut().push(format!("{} c", view.id));
5487            }
5488        });
5489
5490        cx.add_action({
5491            let actions = actions.clone();
5492            move |view: &mut ViewB, _: &Action, cx| {
5493                cx.propagate_action();
5494                actions.borrow_mut().push(format!("{} d", view.id));
5495            }
5496        });
5497
5498        cx.capture_action({
5499            let actions = actions.clone();
5500            move |view: &mut ViewA, _: &Action, cx| {
5501                cx.propagate_action();
5502                actions.borrow_mut().push(format!("{} capture", view.id));
5503            }
5504        });
5505
5506        let observed_actions = Rc::new(RefCell::new(Vec::new()));
5507        cx.observe_actions({
5508            let observed_actions = observed_actions.clone();
5509            move |action_id, _| observed_actions.borrow_mut().push(action_id)
5510        })
5511        .detach();
5512
5513        let (window_id, view_1) =
5514            cx.add_window(Default::default(), |_| ViewA { id: 1, child: None });
5515        let view_2 = cx
5516            .update_window(window_id, |cx| {
5517                let child = cx.add_view(|_| ViewB { id: 2, child: None });
5518                view_1.update(cx, |view, cx| {
5519                    view.child = Some(child.clone().into_any());
5520                    cx.notify();
5521                });
5522                child
5523            })
5524            .unwrap();
5525        let view_3 = cx
5526            .update_window(window_id, |cx| {
5527                let child = cx.add_view(|_| ViewA { id: 3, child: None });
5528                view_2.update(cx, |view, cx| {
5529                    view.child = Some(child.clone().into_any());
5530                    cx.notify();
5531                });
5532                child
5533            })
5534            .unwrap();
5535        let view_4 = cx
5536            .update_window(window_id, |cx| {
5537                let child = cx.add_view(|_| ViewB { id: 4, child: None });
5538                view_3.update(cx, |view, cx| {
5539                    view.child = Some(child.clone().into_any());
5540                    cx.notify();
5541                });
5542                child
5543            })
5544            .unwrap();
5545
5546        cx.update_window(window_id, |cx| {
5547            cx.dispatch_action(Some(view_4.id()), &Action("bar".to_string()))
5548        });
5549
5550        assert_eq!(
5551            *actions.borrow(),
5552            vec![
5553                "1 capture",
5554                "3 capture",
5555                "4 d",
5556                "4 c",
5557                "3 b",
5558                "3 a",
5559                "2 d",
5560                "2 c",
5561                "1 b"
5562            ]
5563        );
5564        assert_eq!(*observed_actions.borrow(), [Action::default().id()]);
5565
5566        // Remove view_1, which doesn't propagate the action
5567
5568        let (window_id, view_2) =
5569            cx.add_window(Default::default(), |_| ViewB { id: 2, child: None });
5570        let view_3 = cx
5571            .update_window(window_id, |cx| {
5572                let child = cx.add_view(|_| ViewA { id: 3, child: None });
5573                view_2.update(cx, |view, cx| {
5574                    view.child = Some(child.clone().into_any());
5575                    cx.notify();
5576                });
5577                child
5578            })
5579            .unwrap();
5580        let view_4 = cx
5581            .update_window(window_id, |cx| {
5582                let child = cx.add_view(|_| ViewB { id: 4, child: None });
5583                view_3.update(cx, |view, cx| {
5584                    view.child = Some(child.clone().into_any());
5585                    cx.notify();
5586                });
5587                child
5588            })
5589            .unwrap();
5590
5591        actions.borrow_mut().clear();
5592        cx.update_window(window_id, |cx| {
5593            cx.dispatch_action(Some(view_4.id()), &Action("bar".to_string()))
5594        });
5595
5596        assert_eq!(
5597            *actions.borrow(),
5598            vec![
5599                "3 capture",
5600                "4 d",
5601                "4 c",
5602                "3 b",
5603                "3 a",
5604                "2 d",
5605                "2 c",
5606                "global"
5607            ]
5608        );
5609        assert_eq!(
5610            *observed_actions.borrow(),
5611            [Action::default().id(), Action::default().id()]
5612        );
5613    }
5614
5615    #[crate::test(self)]
5616    fn test_dispatch_keystroke(cx: &mut AppContext) {
5617        #[derive(Clone, Deserialize, PartialEq)]
5618        pub struct Action(String);
5619
5620        impl_actions!(test, [Action]);
5621
5622        struct View {
5623            id: usize,
5624            keymap_context: KeymapContext,
5625            child: Option<AnyViewHandle>,
5626        }
5627
5628        impl Entity for View {
5629            type Event = ();
5630        }
5631
5632        impl super::View for View {
5633            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5634                self.child
5635                    .as_ref()
5636                    .map(|child| ChildView::new(child, cx).into_any())
5637                    .unwrap_or(Empty::new().into_any())
5638            }
5639
5640            fn ui_name() -> &'static str {
5641                "View"
5642            }
5643
5644            fn keymap_context(&self, _: &AppContext) -> KeymapContext {
5645                self.keymap_context.clone()
5646            }
5647        }
5648
5649        impl View {
5650            fn new(id: usize) -> Self {
5651                View {
5652                    id,
5653                    keymap_context: KeymapContext::default(),
5654                    child: None,
5655                }
5656            }
5657        }
5658
5659        let mut view_1 = View::new(1);
5660        let mut view_2 = View::new(2);
5661        let mut view_3 = View::new(3);
5662        view_1.keymap_context.add_identifier("a");
5663        view_2.keymap_context.add_identifier("a");
5664        view_2.keymap_context.add_identifier("b");
5665        view_3.keymap_context.add_identifier("a");
5666        view_3.keymap_context.add_identifier("b");
5667        view_3.keymap_context.add_identifier("c");
5668
5669        let (window_id, _view_1) = cx.add_window(Default::default(), |cx| {
5670            let view_2 = cx.add_view(|cx| {
5671                let view_3 = cx.add_view(|cx| {
5672                    cx.focus_self();
5673                    view_3
5674                });
5675                view_2.child = Some(view_3.into_any());
5676                view_2
5677            });
5678            view_1.child = Some(view_2.into_any());
5679            view_1
5680        });
5681
5682        // This binding only dispatches an action on view 2 because that view will have
5683        // "a" and "b" in its context, but not "c".
5684        cx.add_bindings(vec![Binding::new(
5685            "a",
5686            Action("a".to_string()),
5687            Some("a && b && !c"),
5688        )]);
5689
5690        cx.add_bindings(vec![Binding::new("b", Action("b".to_string()), None)]);
5691
5692        // This binding only dispatches an action on views 2 and 3, because they have
5693        // a parent view with a in its context
5694        cx.add_bindings(vec![Binding::new(
5695            "c",
5696            Action("c".to_string()),
5697            Some("b > c"),
5698        )]);
5699
5700        // This binding only dispatches an action on view 2, because they have
5701        // a parent view with a in its context
5702        cx.add_bindings(vec![Binding::new(
5703            "d",
5704            Action("d".to_string()),
5705            Some("a && !b > b"),
5706        )]);
5707
5708        let actions = Rc::new(RefCell::new(Vec::new()));
5709        cx.add_action({
5710            let actions = actions.clone();
5711            move |view: &mut View, action: &Action, cx| {
5712                actions
5713                    .borrow_mut()
5714                    .push(format!("{} {}", view.id, action.0));
5715
5716                if action.0 == "b" {
5717                    cx.propagate_action();
5718                }
5719            }
5720        });
5721
5722        cx.add_global_action({
5723            let actions = actions.clone();
5724            move |action: &Action, _| {
5725                actions.borrow_mut().push(format!("global {}", action.0));
5726            }
5727        });
5728
5729        cx.update_window(window_id, |cx| {
5730            cx.dispatch_keystroke(&Keystroke::parse("a").unwrap())
5731        });
5732        assert_eq!(&*actions.borrow(), &["2 a"]);
5733        actions.borrow_mut().clear();
5734
5735        cx.update_window(window_id, |cx| {
5736            cx.dispatch_keystroke(&Keystroke::parse("b").unwrap());
5737        });
5738
5739        assert_eq!(&*actions.borrow(), &["3 b", "2 b", "1 b", "global b"]);
5740        actions.borrow_mut().clear();
5741
5742        cx.update_window(window_id, |cx| {
5743            cx.dispatch_keystroke(&Keystroke::parse("c").unwrap());
5744        });
5745        assert_eq!(&*actions.borrow(), &["3 c"]);
5746        actions.borrow_mut().clear();
5747
5748        cx.update_window(window_id, |cx| {
5749            cx.dispatch_keystroke(&Keystroke::parse("d").unwrap());
5750        });
5751        assert_eq!(&*actions.borrow(), &["2 d"]);
5752        actions.borrow_mut().clear();
5753    }
5754
5755    #[crate::test(self)]
5756    fn test_keystrokes_for_action(cx: &mut AppContext) {
5757        actions!(test, [Action1, Action2, GlobalAction]);
5758
5759        struct View1 {
5760            child: ViewHandle<View2>,
5761        }
5762        struct View2 {}
5763
5764        impl Entity for View1 {
5765            type Event = ();
5766        }
5767        impl Entity for View2 {
5768            type Event = ();
5769        }
5770
5771        impl super::View for View1 {
5772            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5773                ChildView::new(&self.child, cx).into_any()
5774            }
5775            fn ui_name() -> &'static str {
5776                "View1"
5777            }
5778        }
5779        impl super::View for View2 {
5780            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
5781                Empty::new().into_any()
5782            }
5783            fn ui_name() -> &'static str {
5784                "View2"
5785            }
5786        }
5787
5788        let (window_id, view_1) = cx.add_window(Default::default(), |cx| {
5789            let view_2 = cx.add_view(|cx| {
5790                cx.focus_self();
5791                View2 {}
5792            });
5793            View1 { child: view_2 }
5794        });
5795        let view_2 = view_1.read(cx).child.clone();
5796
5797        cx.add_action(|_: &mut View1, _: &Action1, _cx| {});
5798        cx.add_action(|_: &mut View2, _: &Action2, _cx| {});
5799        cx.add_global_action(|_: &GlobalAction, _| {});
5800
5801        cx.add_bindings(vec![
5802            Binding::new("a", Action1, Some("View1")),
5803            Binding::new("b", Action2, Some("View1 > View2")),
5804            Binding::new("c", GlobalAction, Some("View3")), // View 3 does not exist
5805        ]);
5806
5807        cx.update_window(window_id, |cx| {
5808            // Sanity check
5809            assert_eq!(
5810                cx.keystrokes_for_action(view_1.id(), &Action1)
5811                    .unwrap()
5812                    .as_slice(),
5813                &[Keystroke::parse("a").unwrap()]
5814            );
5815            assert_eq!(
5816                cx.keystrokes_for_action(view_2.id(), &Action2)
5817                    .unwrap()
5818                    .as_slice(),
5819                &[Keystroke::parse("b").unwrap()]
5820            );
5821
5822            // The 'a' keystroke propagates up the view tree from view_2
5823            // to view_1. The action, Action1, is handled by view_1.
5824            assert_eq!(
5825                cx.keystrokes_for_action(view_2.id(), &Action1)
5826                    .unwrap()
5827                    .as_slice(),
5828                &[Keystroke::parse("a").unwrap()]
5829            );
5830
5831            // Actions that are handled below the current view don't have bindings
5832            assert_eq!(cx.keystrokes_for_action(view_1.id(), &Action2), None);
5833
5834            // Actions that are handled in other branches of the tree should not have a binding
5835            assert_eq!(cx.keystrokes_for_action(view_2.id(), &GlobalAction), None);
5836
5837            // Check that global actions do not have a binding, even if a binding does exist in another view
5838            assert_eq!(
5839                &available_actions(view_1.id(), cx),
5840                &[
5841                    ("test::Action1", vec![Keystroke::parse("a").unwrap()]),
5842                    ("test::GlobalAction", vec![])
5843                ],
5844            );
5845
5846            // Check that view 1 actions and bindings are available even when called from view 2
5847            assert_eq!(
5848                &available_actions(view_2.id(), cx),
5849                &[
5850                    ("test::Action1", vec![Keystroke::parse("a").unwrap()]),
5851                    ("test::Action2", vec![Keystroke::parse("b").unwrap()]),
5852                    ("test::GlobalAction", vec![]),
5853                ],
5854            );
5855        });
5856
5857        // Produces a list of actions and key bindings
5858        fn available_actions(
5859            view_id: usize,
5860            cx: &WindowContext,
5861        ) -> Vec<(&'static str, Vec<Keystroke>)> {
5862            cx.available_actions(view_id)
5863                .map(|(action_name, _, bindings)| {
5864                    (
5865                        action_name,
5866                        bindings
5867                            .iter()
5868                            .map(|binding| binding.keystrokes()[0].clone())
5869                            .collect::<Vec<_>>(),
5870                    )
5871                })
5872                .sorted_by(|(name1, _), (name2, _)| name1.cmp(name2))
5873                .collect()
5874        }
5875    }
5876
5877    #[crate::test(self)]
5878    async fn test_model_condition(cx: &mut TestAppContext) {
5879        struct Counter(usize);
5880
5881        impl super::Entity for Counter {
5882            type Event = ();
5883        }
5884
5885        impl Counter {
5886            fn inc(&mut self, cx: &mut ModelContext<Self>) {
5887                self.0 += 1;
5888                cx.notify();
5889            }
5890        }
5891
5892        let model = cx.add_model(|_| Counter(0));
5893
5894        let condition1 = model.condition(cx, |model, _| model.0 == 2);
5895        let condition2 = model.condition(cx, |model, _| model.0 == 3);
5896        smol::pin!(condition1, condition2);
5897
5898        model.update(cx, |model, cx| model.inc(cx));
5899        assert_eq!(poll_once(&mut condition1).await, None);
5900        assert_eq!(poll_once(&mut condition2).await, None);
5901
5902        model.update(cx, |model, cx| model.inc(cx));
5903        assert_eq!(poll_once(&mut condition1).await, Some(()));
5904        assert_eq!(poll_once(&mut condition2).await, None);
5905
5906        model.update(cx, |model, cx| model.inc(cx));
5907        assert_eq!(poll_once(&mut condition2).await, Some(()));
5908
5909        model.update(cx, |_, cx| cx.notify());
5910    }
5911
5912    #[crate::test(self)]
5913    #[should_panic]
5914    async fn test_model_condition_timeout(cx: &mut TestAppContext) {
5915        struct Model;
5916
5917        impl super::Entity for Model {
5918            type Event = ();
5919        }
5920
5921        let model = cx.add_model(|_| Model);
5922        model.condition(cx, |_, _| false).await;
5923    }
5924
5925    #[crate::test(self)]
5926    #[should_panic(expected = "model dropped with pending condition")]
5927    async fn test_model_condition_panic_on_drop(cx: &mut TestAppContext) {
5928        struct Model;
5929
5930        impl super::Entity for Model {
5931            type Event = ();
5932        }
5933
5934        let model = cx.add_model(|_| Model);
5935        let condition = model.condition(cx, |_, _| false);
5936        cx.update(|_| drop(model));
5937        condition.await;
5938    }
5939
5940    #[crate::test(self)]
5941    async fn test_view_condition(cx: &mut TestAppContext) {
5942        struct Counter(usize);
5943
5944        impl super::Entity for Counter {
5945            type Event = ();
5946        }
5947
5948        impl super::View for Counter {
5949            fn ui_name() -> &'static str {
5950                "test view"
5951            }
5952
5953            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
5954                Empty::new().into_any()
5955            }
5956        }
5957
5958        impl Counter {
5959            fn inc(&mut self, cx: &mut ViewContext<Self>) {
5960                self.0 += 1;
5961                cx.notify();
5962            }
5963        }
5964
5965        let (_, view) = cx.add_window(|_| Counter(0));
5966
5967        let condition1 = view.condition(cx, |view, _| view.0 == 2);
5968        let condition2 = view.condition(cx, |view, _| view.0 == 3);
5969        smol::pin!(condition1, condition2);
5970
5971        view.update(cx, |view, cx| view.inc(cx));
5972        assert_eq!(poll_once(&mut condition1).await, None);
5973        assert_eq!(poll_once(&mut condition2).await, None);
5974
5975        view.update(cx, |view, cx| view.inc(cx));
5976        assert_eq!(poll_once(&mut condition1).await, Some(()));
5977        assert_eq!(poll_once(&mut condition2).await, None);
5978
5979        view.update(cx, |view, cx| view.inc(cx));
5980        assert_eq!(poll_once(&mut condition2).await, Some(()));
5981        view.update(cx, |_, cx| cx.notify());
5982    }
5983
5984    #[crate::test(self)]
5985    #[should_panic]
5986    async fn test_view_condition_timeout(cx: &mut TestAppContext) {
5987        let (_, view) = cx.add_window(|_| TestView::default());
5988        view.condition(cx, |_, _| false).await;
5989    }
5990
5991    #[crate::test(self)]
5992    #[should_panic(expected = "view dropped with pending condition")]
5993    async fn test_view_condition_panic_on_drop(cx: &mut TestAppContext) {
5994        let (window_id, _root_view) = cx.add_window(|_| TestView::default());
5995        let view = cx.add_view(window_id, |_| TestView::default());
5996
5997        let condition = view.condition(cx, |_, _| false);
5998        cx.update(|_| drop(view));
5999        condition.await;
6000    }
6001
6002    #[crate::test(self)]
6003    fn test_refresh_windows(cx: &mut AppContext) {
6004        struct View(usize);
6005
6006        impl super::Entity for View {
6007            type Event = ();
6008        }
6009
6010        impl super::View for View {
6011            fn ui_name() -> &'static str {
6012                "test view"
6013            }
6014
6015            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6016                Empty::new().into_any_named(format!("render count: {}", post_inc(&mut self.0)))
6017            }
6018        }
6019
6020        let (window_id, root_view) = cx.add_window(Default::default(), |_| View(0));
6021        cx.update_window(window_id, |cx| {
6022            assert_eq!(
6023                cx.window.rendered_views[&root_view.id()].name(),
6024                Some("render count: 0")
6025            );
6026        });
6027
6028        let view = cx
6029            .update_window(window_id, |cx| {
6030                cx.refresh_windows();
6031                cx.add_view(|_| View(0))
6032            })
6033            .unwrap();
6034
6035        cx.update_window(window_id, |cx| {
6036            assert_eq!(
6037                cx.window.rendered_views[&root_view.id()].name(),
6038                Some("render count: 1")
6039            );
6040            assert_eq!(
6041                cx.window.rendered_views[&view.id()].name(),
6042                Some("render count: 0")
6043            );
6044        });
6045
6046        cx.update(|cx| cx.refresh_windows());
6047
6048        cx.update_window(window_id, |cx| {
6049            assert_eq!(
6050                cx.window.rendered_views[&root_view.id()].name(),
6051                Some("render count: 2")
6052            );
6053            assert_eq!(
6054                cx.window.rendered_views[&view.id()].name(),
6055                Some("render count: 1")
6056            );
6057        });
6058
6059        cx.update(|cx| {
6060            cx.refresh_windows();
6061            drop(view);
6062        });
6063
6064        cx.update_window(window_id, |cx| {
6065            assert_eq!(
6066                cx.window.rendered_views[&root_view.id()].name(),
6067                Some("render count: 3")
6068            );
6069            assert_eq!(cx.window.rendered_views.len(), 1);
6070        });
6071    }
6072
6073    #[crate::test(self)]
6074    async fn test_labeled_tasks(cx: &mut TestAppContext) {
6075        assert_eq!(None, cx.update(|cx| cx.active_labeled_tasks().next()));
6076        let (mut sender, mut reciever) = postage::oneshot::channel::<()>();
6077        let task = cx
6078            .update(|cx| cx.spawn_labeled("Test Label", |_| async move { reciever.recv().await }));
6079
6080        assert_eq!(
6081            Some("Test Label"),
6082            cx.update(|cx| cx.active_labeled_tasks().next())
6083        );
6084        sender
6085            .send(())
6086            .await
6087            .expect("Could not send message to complete task");
6088        task.await;
6089
6090        assert_eq!(None, cx.update(|cx| cx.active_labeled_tasks().next()));
6091    }
6092
6093    #[crate::test(self)]
6094    async fn test_window_activation(cx: &mut TestAppContext) {
6095        struct View(&'static str);
6096
6097        impl super::Entity for View {
6098            type Event = ();
6099        }
6100
6101        impl super::View for View {
6102            fn ui_name() -> &'static str {
6103                "test view"
6104            }
6105
6106            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6107                Empty::new().into_any()
6108            }
6109        }
6110
6111        let events = Rc::new(RefCell::new(Vec::new()));
6112        let (window_1, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6113            cx.observe_window_activation({
6114                let events = events.clone();
6115                move |this, active, _| events.borrow_mut().push((this.0, active))
6116            })
6117            .detach();
6118            View("window 1")
6119        });
6120        assert_eq!(mem::take(&mut *events.borrow_mut()), [("window 1", true)]);
6121
6122        let (window_2, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6123            cx.observe_window_activation({
6124                let events = events.clone();
6125                move |this, active, _| events.borrow_mut().push((this.0, active))
6126            })
6127            .detach();
6128            View("window 2")
6129        });
6130        assert_eq!(
6131            mem::take(&mut *events.borrow_mut()),
6132            [("window 1", false), ("window 2", true)]
6133        );
6134
6135        let (window_3, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6136            cx.observe_window_activation({
6137                let events = events.clone();
6138                move |this, active, _| events.borrow_mut().push((this.0, active))
6139            })
6140            .detach();
6141            View("window 3")
6142        });
6143        assert_eq!(
6144            mem::take(&mut *events.borrow_mut()),
6145            [("window 2", false), ("window 3", true)]
6146        );
6147
6148        cx.simulate_window_activation(Some(window_2));
6149        assert_eq!(
6150            mem::take(&mut *events.borrow_mut()),
6151            [("window 3", false), ("window 2", true)]
6152        );
6153
6154        cx.simulate_window_activation(Some(window_1));
6155        assert_eq!(
6156            mem::take(&mut *events.borrow_mut()),
6157            [("window 2", false), ("window 1", true)]
6158        );
6159
6160        cx.simulate_window_activation(Some(window_3));
6161        assert_eq!(
6162            mem::take(&mut *events.borrow_mut()),
6163            [("window 1", false), ("window 3", true)]
6164        );
6165
6166        cx.simulate_window_activation(Some(window_3));
6167        assert_eq!(mem::take(&mut *events.borrow_mut()), []);
6168    }
6169
6170    #[crate::test(self)]
6171    fn test_child_view(cx: &mut TestAppContext) {
6172        struct Child {
6173            rendered: Rc<Cell<bool>>,
6174            dropped: Rc<Cell<bool>>,
6175        }
6176
6177        impl super::Entity for Child {
6178            type Event = ();
6179        }
6180
6181        impl super::View for Child {
6182            fn ui_name() -> &'static str {
6183                "child view"
6184            }
6185
6186            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6187                self.rendered.set(true);
6188                Empty::new().into_any()
6189            }
6190        }
6191
6192        impl Drop for Child {
6193            fn drop(&mut self) {
6194                self.dropped.set(true);
6195            }
6196        }
6197
6198        struct Parent {
6199            child: Option<ViewHandle<Child>>,
6200        }
6201
6202        impl super::Entity for Parent {
6203            type Event = ();
6204        }
6205
6206        impl super::View for Parent {
6207            fn ui_name() -> &'static str {
6208                "parent view"
6209            }
6210
6211            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
6212                if let Some(child) = self.child.as_ref() {
6213                    ChildView::new(child, cx).into_any()
6214                } else {
6215                    Empty::new().into_any()
6216                }
6217            }
6218        }
6219
6220        let child_rendered = Rc::new(Cell::new(false));
6221        let child_dropped = Rc::new(Cell::new(false));
6222        let (_, root_view) = cx.add_window(|cx| Parent {
6223            child: Some(cx.add_view(|_| Child {
6224                rendered: child_rendered.clone(),
6225                dropped: child_dropped.clone(),
6226            })),
6227        });
6228        assert!(child_rendered.take());
6229        assert!(!child_dropped.take());
6230
6231        root_view.update(cx, |view, cx| {
6232            view.child.take();
6233            cx.notify();
6234        });
6235        assert!(!child_rendered.take());
6236        assert!(child_dropped.take());
6237    }
6238
6239    #[derive(Default)]
6240    struct TestView {
6241        events: Vec<String>,
6242    }
6243
6244    impl Entity for TestView {
6245        type Event = String;
6246    }
6247
6248    impl View for TestView {
6249        fn ui_name() -> &'static str {
6250            "TestView"
6251        }
6252
6253        fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6254            Empty::new().into_any()
6255        }
6256    }
6257}