app.rs

   1use crate::{
   2    elements::ElementBox,
   3    executor,
   4    keymap::{self, Keystroke},
   5    platform::{self, Platform, PromptLevel, WindowOptions},
   6    presenter::Presenter,
   7    util::{post_inc, timeout},
   8    AssetCache, AssetSource, ClipboardItem, EventContext, FontCache, PathPromptOptions,
   9    TextLayoutCache,
  10};
  11use anyhow::{anyhow, Result};
  12use async_task::Task;
  13use keymap::MatchResult;
  14use parking_lot::{Mutex, RwLock};
  15use pathfinder_geometry::{rect::RectF, vector::vec2f};
  16use platform::Event;
  17use postage::{mpsc, sink::Sink as _, stream::Stream as _};
  18use smol::prelude::*;
  19use std::{
  20    any::{type_name, Any, TypeId},
  21    cell::RefCell,
  22    collections::{hash_map::Entry, HashMap, HashSet, VecDeque},
  23    fmt::{self, Debug},
  24    hash::{Hash, Hasher},
  25    marker::PhantomData,
  26    ops::{Deref, DerefMut},
  27    path::{Path, PathBuf},
  28    rc::{self, Rc},
  29    sync::{Arc, Weak},
  30    time::Duration,
  31};
  32
  33pub trait Entity: 'static + Send + Sync {
  34    type Event;
  35
  36    fn release(&mut self, _: &mut MutableAppContext) {}
  37}
  38
  39pub trait View: Entity {
  40    fn ui_name() -> &'static str;
  41    fn render<'a>(&self, cx: &AppContext) -> ElementBox;
  42    fn on_focus(&mut self, _: &mut ViewContext<Self>) {}
  43    fn on_blur(&mut self, _: &mut ViewContext<Self>) {}
  44    fn keymap_context(&self, _: &AppContext) -> keymap::Context {
  45        Self::default_keymap_context()
  46    }
  47    fn default_keymap_context() -> keymap::Context {
  48        let mut cx = keymap::Context::default();
  49        cx.set.insert(Self::ui_name().into());
  50        cx
  51    }
  52}
  53
  54pub trait ReadModel {
  55    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T;
  56}
  57
  58pub trait ReadModelWith {
  59    fn read_model_with<E: Entity, F: FnOnce(&E, &AppContext) -> T, T>(
  60        &self,
  61        handle: &ModelHandle<E>,
  62        read: F,
  63    ) -> T;
  64}
  65
  66pub trait UpdateModel {
  67    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
  68    where
  69        T: Entity,
  70        F: FnOnce(&mut T, &mut ModelContext<T>) -> S;
  71}
  72
  73pub trait ReadView {
  74    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T;
  75}
  76
  77pub trait ReadViewWith {
  78    fn read_view_with<V, F, T>(&self, handle: &ViewHandle<V>, read: F) -> T
  79    where
  80        V: View,
  81        F: FnOnce(&V, &AppContext) -> T;
  82}
  83
  84pub trait UpdateView {
  85    fn update_view<T, F, S>(&mut self, handle: &ViewHandle<T>, update: F) -> S
  86    where
  87        T: View,
  88        F: FnOnce(&mut T, &mut ViewContext<T>) -> S;
  89}
  90
  91pub struct Menu<'a> {
  92    pub name: &'a str,
  93    pub items: Vec<MenuItem<'a>>,
  94}
  95
  96pub enum MenuItem<'a> {
  97    Action {
  98        name: &'a str,
  99        keystroke: Option<&'a str>,
 100        action: &'a str,
 101        arg: Option<Box<dyn Any + 'static>>,
 102    },
 103    Separator,
 104}
 105
 106#[derive(Clone)]
 107pub struct App(Rc<RefCell<MutableAppContext>>);
 108
 109#[derive(Clone)]
 110pub struct AsyncAppContext(Rc<RefCell<MutableAppContext>>);
 111
 112pub struct BackgroundAppContext(*const RefCell<MutableAppContext>);
 113
 114#[derive(Clone)]
 115pub struct TestAppContext {
 116    cx: Rc<RefCell<MutableAppContext>>,
 117    foreground_platform: Rc<platform::test::ForegroundPlatform>,
 118}
 119
 120impl App {
 121    pub fn test<T, F: FnOnce(&mut MutableAppContext) -> T>(f: F) -> T {
 122        let foreground_platform = platform::test::foreground_platform();
 123        let platform = platform::test::platform();
 124        let foreground = Rc::new(executor::Foreground::test());
 125        let cx = Rc::new(RefCell::new(MutableAppContext::new(
 126            foreground,
 127            Arc::new(executor::Background::new()),
 128            Arc::new(platform),
 129            Rc::new(foreground_platform),
 130            (),
 131        )));
 132        cx.borrow_mut().weak_self = Some(Rc::downgrade(&cx));
 133        let mut cx = cx.borrow_mut();
 134        f(&mut *cx)
 135    }
 136
 137    pub fn new(asset_source: impl AssetSource) -> Result<Self> {
 138        let platform = platform::current::platform();
 139        let foreground_platform = platform::current::foreground_platform();
 140        let foreground = Rc::new(executor::Foreground::platform(platform.dispatcher())?);
 141        let app = Self(Rc::new(RefCell::new(MutableAppContext::new(
 142            foreground,
 143            Arc::new(executor::Background::new()),
 144            platform.clone(),
 145            foreground_platform.clone(),
 146            asset_source,
 147        ))));
 148
 149        let cx = app.0.clone();
 150        foreground_platform.on_menu_command(Box::new(move |command, arg| {
 151            let mut cx = cx.borrow_mut();
 152            if let Some(key_window_id) = cx.cx.platform.key_window_id() {
 153                if let Some((presenter, _)) = cx.presenters_and_platform_windows.get(&key_window_id)
 154                {
 155                    let presenter = presenter.clone();
 156                    let path = presenter.borrow().dispatch_path(cx.as_ref());
 157                    cx.dispatch_action_any(key_window_id, &path, command, arg.unwrap_or(&()));
 158                } else {
 159                    cx.dispatch_global_action_any(command, arg.unwrap_or(&()));
 160                }
 161            } else {
 162                cx.dispatch_global_action_any(command, arg.unwrap_or(&()));
 163            }
 164        }));
 165
 166        app.0.borrow_mut().weak_self = Some(Rc::downgrade(&app.0));
 167        Ok(app)
 168    }
 169
 170    pub fn on_become_active<F>(self, mut callback: F) -> Self
 171    where
 172        F: 'static + FnMut(&mut MutableAppContext),
 173    {
 174        let cx = self.0.clone();
 175        self.0
 176            .borrow_mut()
 177            .foreground_platform
 178            .on_become_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 179        self
 180    }
 181
 182    pub fn on_resign_active<F>(self, mut callback: F) -> Self
 183    where
 184        F: 'static + FnMut(&mut MutableAppContext),
 185    {
 186        let cx = self.0.clone();
 187        self.0
 188            .borrow_mut()
 189            .foreground_platform
 190            .on_resign_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 191        self
 192    }
 193
 194    pub fn on_event<F>(self, mut callback: F) -> Self
 195    where
 196        F: 'static + FnMut(Event, &mut MutableAppContext) -> bool,
 197    {
 198        let cx = self.0.clone();
 199        self.0
 200            .borrow_mut()
 201            .foreground_platform
 202            .on_event(Box::new(move |event| {
 203                callback(event, &mut *cx.borrow_mut())
 204            }));
 205        self
 206    }
 207
 208    pub fn on_open_files<F>(self, mut callback: F) -> Self
 209    where
 210        F: 'static + FnMut(Vec<PathBuf>, &mut MutableAppContext),
 211    {
 212        let cx = self.0.clone();
 213        self.0
 214            .borrow_mut()
 215            .foreground_platform
 216            .on_open_files(Box::new(move |paths| {
 217                callback(paths, &mut *cx.borrow_mut())
 218            }));
 219        self
 220    }
 221
 222    pub fn run<F>(self, on_finish_launching: F)
 223    where
 224        F: 'static + FnOnce(&mut MutableAppContext),
 225    {
 226        let platform = self.0.borrow().foreground_platform.clone();
 227        platform.run(Box::new(move || {
 228            let mut cx = self.0.borrow_mut();
 229            on_finish_launching(&mut *cx);
 230        }))
 231    }
 232
 233    pub fn font_cache(&self) -> Arc<FontCache> {
 234        self.0.borrow().cx.font_cache.clone()
 235    }
 236
 237    fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 238        let mut state = self.0.borrow_mut();
 239        state.pending_flushes += 1;
 240        let result = callback(&mut *state);
 241        state.flush_effects();
 242        result
 243    }
 244}
 245
 246impl TestAppContext {
 247    pub fn new(
 248        foreground: Rc<executor::Foreground>,
 249        background: Arc<executor::Background>,
 250        first_entity_id: usize,
 251    ) -> Self {
 252        let platform = Arc::new(platform::test::platform());
 253        let foreground_platform = Rc::new(platform::test::foreground_platform());
 254        let mut cx = MutableAppContext::new(
 255            foreground.clone(),
 256            background,
 257            platform,
 258            foreground_platform.clone(),
 259            (),
 260        );
 261        cx.next_entity_id = first_entity_id;
 262        let cx = TestAppContext {
 263            cx: Rc::new(RefCell::new(cx)),
 264            foreground_platform,
 265        };
 266        cx.cx.borrow_mut().weak_self = Some(Rc::downgrade(&cx.cx));
 267        cx
 268    }
 269
 270    pub fn dispatch_action<T: 'static + Any>(
 271        &self,
 272        window_id: usize,
 273        responder_chain: Vec<usize>,
 274        name: &str,
 275        arg: T,
 276    ) {
 277        self.cx.borrow_mut().dispatch_action_any(
 278            window_id,
 279            &responder_chain,
 280            name,
 281            Box::new(arg).as_ref(),
 282        );
 283    }
 284
 285    pub fn dispatch_global_action<T: 'static + Any>(&self, name: &str, arg: T) {
 286        self.cx.borrow_mut().dispatch_global_action(name, arg);
 287    }
 288
 289    pub fn dispatch_keystroke(
 290        &self,
 291        window_id: usize,
 292        responder_chain: Vec<usize>,
 293        keystroke: &Keystroke,
 294    ) -> Result<bool> {
 295        let mut state = self.cx.borrow_mut();
 296        state.dispatch_keystroke(window_id, responder_chain, keystroke)
 297    }
 298
 299    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 300    where
 301        T: Entity,
 302        F: FnOnce(&mut ModelContext<T>) -> T,
 303    {
 304        let mut state = self.cx.borrow_mut();
 305        state.pending_flushes += 1;
 306        let handle = state.add_model(build_model);
 307        state.flush_effects();
 308        handle
 309    }
 310
 311    pub fn add_window<T, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<T>)
 312    where
 313        T: View,
 314        F: FnOnce(&mut ViewContext<T>) -> T,
 315    {
 316        self.cx.borrow_mut().add_window(build_root_view)
 317    }
 318
 319    pub fn window_ids(&self) -> Vec<usize> {
 320        self.cx.borrow().window_ids().collect()
 321    }
 322
 323    pub fn root_view<T: View>(&self, window_id: usize) -> Option<ViewHandle<T>> {
 324        self.cx.borrow().root_view(window_id)
 325    }
 326
 327    pub fn add_view<T, F>(&mut self, window_id: usize, build_view: F) -> ViewHandle<T>
 328    where
 329        T: View,
 330        F: FnOnce(&mut ViewContext<T>) -> T,
 331    {
 332        let mut state = self.cx.borrow_mut();
 333        state.pending_flushes += 1;
 334        let handle = state.add_view(window_id, build_view);
 335        state.flush_effects();
 336        handle
 337    }
 338
 339    pub fn add_option_view<T, F>(
 340        &mut self,
 341        window_id: usize,
 342        build_view: F,
 343    ) -> Option<ViewHandle<T>>
 344    where
 345        T: View,
 346        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
 347    {
 348        let mut state = self.cx.borrow_mut();
 349        state.pending_flushes += 1;
 350        let handle = state.add_option_view(window_id, build_view);
 351        state.flush_effects();
 352        handle
 353    }
 354
 355    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 356        callback(self.cx.borrow().as_ref())
 357    }
 358
 359    pub fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 360        let mut state = self.cx.borrow_mut();
 361        // Don't increment pending flushes in order to effects to be flushed before the callback
 362        // completes, which is helpful in tests.
 363        let result = callback(&mut *state);
 364        // Flush effects after the callback just in case there are any. This can happen in edge
 365        // cases such as the closure dropping handles.
 366        state.flush_effects();
 367        result
 368    }
 369
 370    pub fn to_async(&self) -> AsyncAppContext {
 371        AsyncAppContext(self.cx.clone())
 372    }
 373
 374    pub fn font_cache(&self) -> Arc<FontCache> {
 375        self.cx.borrow().cx.font_cache.clone()
 376    }
 377
 378    pub fn platform(&self) -> Arc<dyn platform::Platform> {
 379        self.cx.borrow().cx.platform.clone()
 380    }
 381
 382    pub fn foreground(&self) -> Rc<executor::Foreground> {
 383        self.cx.borrow().foreground().clone()
 384    }
 385
 386    pub fn background(&self) -> Arc<executor::Background> {
 387        self.cx.borrow().background().clone()
 388    }
 389
 390    pub fn simulate_new_path_selection(&self, result: impl FnOnce(PathBuf) -> Option<PathBuf>) {
 391        self.foreground_platform.simulate_new_path_selection(result);
 392    }
 393
 394    pub fn did_prompt_for_new_path(&self) -> bool {
 395        self.foreground_platform.as_ref().did_prompt_for_new_path()
 396    }
 397
 398    pub fn simulate_prompt_answer(&self, window_id: usize, answer: usize) {
 399        let mut state = self.cx.borrow_mut();
 400        let (_, window) = state
 401            .presenters_and_platform_windows
 402            .get_mut(&window_id)
 403            .unwrap();
 404        let test_window = window
 405            .as_any_mut()
 406            .downcast_mut::<platform::test::Window>()
 407            .unwrap();
 408        let callback = test_window
 409            .last_prompt
 410            .take()
 411            .expect("prompt was not called");
 412        (callback)(answer);
 413    }
 414}
 415
 416impl AsyncAppContext {
 417    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
 418    where
 419        F: FnOnce(AsyncAppContext) -> Fut,
 420        Fut: 'static + Future<Output = T>,
 421        T: 'static,
 422    {
 423        self.0.borrow().foreground.spawn(f(self.clone()))
 424    }
 425
 426    pub fn read<T, F: FnOnce(&AppContext) -> T>(&mut self, callback: F) -> T {
 427        callback(self.0.borrow().as_ref())
 428    }
 429
 430    pub fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 431        let mut state = self.0.borrow_mut();
 432        state.pending_flushes += 1;
 433        let result = callback(&mut *state);
 434        state.flush_effects();
 435        result
 436    }
 437
 438    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 439    where
 440        T: Entity,
 441        F: FnOnce(&mut ModelContext<T>) -> T,
 442    {
 443        self.update(|cx| cx.add_model(build_model))
 444    }
 445
 446    pub fn platform(&self) -> Arc<dyn Platform> {
 447        self.0.borrow().platform()
 448    }
 449
 450    pub fn foreground(&self) -> Rc<executor::Foreground> {
 451        self.0.borrow().foreground.clone()
 452    }
 453
 454    pub fn background(&self) -> Arc<executor::Background> {
 455        self.0.borrow().cx.background.clone()
 456    }
 457}
 458
 459impl UpdateModel for AsyncAppContext {
 460    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
 461    where
 462        T: Entity,
 463        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
 464    {
 465        let mut state = self.0.borrow_mut();
 466        state.pending_flushes += 1;
 467        let result = state.update_model(handle, update);
 468        state.flush_effects();
 469        result
 470    }
 471}
 472
 473impl ReadModelWith for AsyncAppContext {
 474    fn read_model_with<E: Entity, F: FnOnce(&E, &AppContext) -> T, T>(
 475        &self,
 476        handle: &ModelHandle<E>,
 477        read: F,
 478    ) -> T {
 479        let cx = self.0.borrow();
 480        let cx = cx.as_ref();
 481        read(handle.read(cx), cx)
 482    }
 483}
 484
 485impl UpdateView for AsyncAppContext {
 486    fn update_view<T, F, S>(&mut self, handle: &ViewHandle<T>, update: F) -> S
 487    where
 488        T: View,
 489        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
 490    {
 491        let mut state = self.0.borrow_mut();
 492        state.pending_flushes += 1;
 493        let result = state.update_view(handle, update);
 494        state.flush_effects();
 495        result
 496    }
 497}
 498
 499impl ReadViewWith for AsyncAppContext {
 500    fn read_view_with<V, F, T>(&self, handle: &ViewHandle<V>, read: F) -> T
 501    where
 502        V: View,
 503        F: FnOnce(&V, &AppContext) -> T,
 504    {
 505        let cx = self.0.borrow();
 506        let cx = cx.as_ref();
 507        read(handle.read(cx), cx)
 508    }
 509}
 510
 511impl UpdateModel for TestAppContext {
 512    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
 513    where
 514        T: Entity,
 515        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
 516    {
 517        let mut state = self.cx.borrow_mut();
 518        state.pending_flushes += 1;
 519        let result = state.update_model(handle, update);
 520        state.flush_effects();
 521        result
 522    }
 523}
 524
 525impl ReadModelWith for TestAppContext {
 526    fn read_model_with<E: Entity, F: FnOnce(&E, &AppContext) -> T, T>(
 527        &self,
 528        handle: &ModelHandle<E>,
 529        read: F,
 530    ) -> T {
 531        let cx = self.cx.borrow();
 532        let cx = cx.as_ref();
 533        read(handle.read(cx), cx)
 534    }
 535}
 536
 537impl UpdateView for TestAppContext {
 538    fn update_view<T, F, S>(&mut self, handle: &ViewHandle<T>, update: F) -> S
 539    where
 540        T: View,
 541        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
 542    {
 543        let mut state = self.cx.borrow_mut();
 544        state.pending_flushes += 1;
 545        let result = state.update_view(handle, update);
 546        state.flush_effects();
 547        result
 548    }
 549}
 550
 551impl ReadViewWith for TestAppContext {
 552    fn read_view_with<V, F, T>(&self, handle: &ViewHandle<V>, read: F) -> T
 553    where
 554        V: View,
 555        F: FnOnce(&V, &AppContext) -> T,
 556    {
 557        let cx = self.cx.borrow();
 558        let cx = cx.as_ref();
 559        read(handle.read(cx), cx)
 560    }
 561}
 562
 563type ActionCallback =
 564    dyn FnMut(&mut dyn AnyView, &dyn Any, &mut MutableAppContext, usize, usize) -> bool;
 565
 566type GlobalActionCallback = dyn FnMut(&dyn Any, &mut MutableAppContext);
 567
 568pub struct MutableAppContext {
 569    weak_self: Option<rc::Weak<RefCell<Self>>>,
 570    foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 571    assets: Arc<AssetCache>,
 572    cx: AppContext,
 573    actions: HashMap<TypeId, HashMap<String, Vec<Box<ActionCallback>>>>,
 574    global_actions: HashMap<String, Vec<Box<GlobalActionCallback>>>,
 575    keystroke_matcher: keymap::Matcher,
 576    next_entity_id: usize,
 577    next_window_id: usize,
 578    subscriptions: HashMap<usize, Vec<Subscription>>,
 579    model_observations: HashMap<usize, Vec<ModelObservation>>,
 580    view_observations: HashMap<usize, Vec<ViewObservation>>,
 581    presenters_and_platform_windows:
 582        HashMap<usize, (Rc<RefCell<Presenter>>, Box<dyn platform::Window>)>,
 583    debug_elements_callbacks: HashMap<usize, Box<dyn Fn(&AppContext) -> crate::json::Value>>,
 584    foreground: Rc<executor::Foreground>,
 585    pending_effects: VecDeque<Effect>,
 586    pending_flushes: usize,
 587    flushing_effects: bool,
 588}
 589
 590impl MutableAppContext {
 591    fn new(
 592        foreground: Rc<executor::Foreground>,
 593        background: Arc<executor::Background>,
 594        platform: Arc<dyn platform::Platform>,
 595        foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 596        asset_source: impl AssetSource,
 597    ) -> Self {
 598        let fonts = platform.fonts();
 599        Self {
 600            weak_self: None,
 601            foreground_platform,
 602            assets: Arc::new(AssetCache::new(asset_source)),
 603            cx: AppContext {
 604                models: Default::default(),
 605                views: Default::default(),
 606                windows: Default::default(),
 607                values: Default::default(),
 608                ref_counts: Arc::new(Mutex::new(RefCounts::default())),
 609                background,
 610                font_cache: Arc::new(FontCache::new(fonts)),
 611                platform,
 612            },
 613            actions: HashMap::new(),
 614            global_actions: HashMap::new(),
 615            keystroke_matcher: keymap::Matcher::default(),
 616            next_entity_id: 0,
 617            next_window_id: 0,
 618            subscriptions: HashMap::new(),
 619            model_observations: HashMap::new(),
 620            view_observations: HashMap::new(),
 621            presenters_and_platform_windows: HashMap::new(),
 622            debug_elements_callbacks: HashMap::new(),
 623            foreground,
 624            pending_effects: VecDeque::new(),
 625            pending_flushes: 0,
 626            flushing_effects: false,
 627        }
 628    }
 629
 630    pub fn upgrade(&self) -> App {
 631        App(self.weak_self.as_ref().unwrap().upgrade().unwrap())
 632    }
 633
 634    pub fn platform(&self) -> Arc<dyn platform::Platform> {
 635        self.cx.platform.clone()
 636    }
 637
 638    pub fn font_cache(&self) -> &Arc<FontCache> {
 639        &self.cx.font_cache
 640    }
 641
 642    pub fn foreground(&self) -> &Rc<executor::Foreground> {
 643        &self.foreground
 644    }
 645
 646    pub fn background(&self) -> &Arc<executor::Background> {
 647        &self.cx.background
 648    }
 649
 650    pub fn on_debug_elements<F>(&mut self, window_id: usize, callback: F)
 651    where
 652        F: 'static + Fn(&AppContext) -> crate::json::Value,
 653    {
 654        self.debug_elements_callbacks
 655            .insert(window_id, Box::new(callback));
 656    }
 657
 658    pub fn debug_elements(&self, window_id: usize) -> Option<crate::json::Value> {
 659        self.debug_elements_callbacks
 660            .get(&window_id)
 661            .map(|debug_elements| debug_elements(&self.cx))
 662    }
 663
 664    pub fn add_action<S, V, T, F>(&mut self, name: S, mut handler: F)
 665    where
 666        S: Into<String>,
 667        V: View,
 668        T: Any,
 669        F: 'static + FnMut(&mut V, &T, &mut ViewContext<V>),
 670    {
 671        let name = name.into();
 672        let name_clone = name.clone();
 673        let handler = Box::new(
 674            move |view: &mut dyn AnyView,
 675                  arg: &dyn Any,
 676                  cx: &mut MutableAppContext,
 677                  window_id: usize,
 678                  view_id: usize| {
 679                match arg.downcast_ref() {
 680                    Some(arg) => {
 681                        let mut cx = ViewContext::new(cx, window_id, view_id);
 682                        handler(
 683                            view.as_any_mut()
 684                                .downcast_mut()
 685                                .expect("downcast is type safe"),
 686                            arg,
 687                            &mut cx,
 688                        );
 689                        cx.halt_action_dispatch
 690                    }
 691                    None => {
 692                        log::error!("Could not downcast argument for action {}", name_clone);
 693                        false
 694                    }
 695                }
 696            },
 697        );
 698
 699        self.actions
 700            .entry(TypeId::of::<V>())
 701            .or_default()
 702            .entry(name)
 703            .or_default()
 704            .push(handler);
 705    }
 706
 707    pub fn add_global_action<S, T, F>(&mut self, name: S, mut handler: F)
 708    where
 709        S: Into<String>,
 710        T: 'static + Any,
 711        F: 'static + FnMut(&T, &mut MutableAppContext),
 712    {
 713        let name = name.into();
 714        let name_clone = name.clone();
 715        let handler = Box::new(move |arg: &dyn Any, cx: &mut MutableAppContext| {
 716            if let Some(arg) = arg.downcast_ref() {
 717                handler(arg, cx);
 718            } else {
 719                log::error!("Could not downcast argument for action {}", name_clone);
 720            }
 721        });
 722
 723        self.global_actions.entry(name).or_default().push(handler);
 724    }
 725
 726    pub fn window_ids(&self) -> impl Iterator<Item = usize> + '_ {
 727        self.cx.windows.keys().cloned()
 728    }
 729
 730    pub fn root_view<T: View>(&self, window_id: usize) -> Option<ViewHandle<T>> {
 731        self.cx
 732            .windows
 733            .get(&window_id)
 734            .and_then(|window| window.root_view.clone().downcast::<T>())
 735    }
 736
 737    pub fn root_view_id(&self, window_id: usize) -> Option<usize> {
 738        self.cx.root_view_id(window_id)
 739    }
 740
 741    pub fn focused_view_id(&self, window_id: usize) -> Option<usize> {
 742        self.cx.focused_view_id(window_id)
 743    }
 744
 745    pub fn render_view(&self, window_id: usize, view_id: usize) -> Result<ElementBox> {
 746        self.cx.render_view(window_id, view_id)
 747    }
 748
 749    pub fn render_views(&self, window_id: usize) -> HashMap<usize, ElementBox> {
 750        self.cx.render_views(window_id)
 751    }
 752
 753    pub fn update<T, F: FnOnce() -> T>(&mut self, callback: F) -> T {
 754        self.pending_flushes += 1;
 755        let result = callback();
 756        self.flush_effects();
 757        result
 758    }
 759
 760    pub fn set_menus(&mut self, menus: Vec<Menu>) {
 761        self.foreground_platform.set_menus(menus);
 762    }
 763
 764    fn prompt<F>(
 765        &self,
 766        window_id: usize,
 767        level: PromptLevel,
 768        msg: &str,
 769        answers: &[&str],
 770        done_fn: F,
 771    ) where
 772        F: 'static + FnOnce(usize, &mut MutableAppContext),
 773    {
 774        let app = self.weak_self.as_ref().unwrap().upgrade().unwrap();
 775        let foreground = self.foreground.clone();
 776        let (_, window) = &self.presenters_and_platform_windows[&window_id];
 777        window.prompt(
 778            level,
 779            msg,
 780            answers,
 781            Box::new(move |answer| {
 782                foreground
 783                    .spawn(async move { (done_fn)(answer, &mut *app.borrow_mut()) })
 784                    .detach();
 785            }),
 786        );
 787    }
 788
 789    pub fn prompt_for_paths<F>(&self, options: PathPromptOptions, done_fn: F)
 790    where
 791        F: 'static + FnOnce(Option<Vec<PathBuf>>, &mut MutableAppContext),
 792    {
 793        let app = self.weak_self.as_ref().unwrap().upgrade().unwrap();
 794        let foreground = self.foreground.clone();
 795        self.foreground_platform.prompt_for_paths(
 796            options,
 797            Box::new(move |paths| {
 798                foreground
 799                    .spawn(async move { (done_fn)(paths, &mut *app.borrow_mut()) })
 800                    .detach();
 801            }),
 802        );
 803    }
 804
 805    pub fn prompt_for_new_path<F>(&self, directory: &Path, done_fn: F)
 806    where
 807        F: 'static + FnOnce(Option<PathBuf>, &mut MutableAppContext),
 808    {
 809        let app = self.weak_self.as_ref().unwrap().upgrade().unwrap();
 810        let foreground = self.foreground.clone();
 811        self.foreground_platform.prompt_for_new_path(
 812            directory,
 813            Box::new(move |path| {
 814                foreground
 815                    .spawn(async move { (done_fn)(path, &mut *app.borrow_mut()) })
 816                    .detach();
 817            }),
 818        );
 819    }
 820
 821    pub(crate) fn notify_view(&mut self, window_id: usize, view_id: usize) {
 822        self.pending_effects
 823            .push_back(Effect::ViewNotification { window_id, view_id });
 824    }
 825
 826    pub fn dispatch_action<T: 'static + Any>(
 827        &mut self,
 828        window_id: usize,
 829        responder_chain: Vec<usize>,
 830        name: &str,
 831        arg: T,
 832    ) {
 833        self.dispatch_action_any(window_id, &responder_chain, name, Box::new(arg).as_ref());
 834    }
 835
 836    pub(crate) fn dispatch_action_any(
 837        &mut self,
 838        window_id: usize,
 839        path: &[usize],
 840        name: &str,
 841        arg: &dyn Any,
 842    ) -> bool {
 843        self.pending_flushes += 1;
 844        let mut halted_dispatch = false;
 845
 846        for view_id in path.iter().rev() {
 847            if let Some(mut view) = self.cx.views.remove(&(window_id, *view_id)) {
 848                let type_id = view.as_any().type_id();
 849
 850                if let Some((name, mut handlers)) = self
 851                    .actions
 852                    .get_mut(&type_id)
 853                    .and_then(|h| h.remove_entry(name))
 854                {
 855                    for handler in handlers.iter_mut().rev() {
 856                        let halt_dispatch = handler(view.as_mut(), arg, self, window_id, *view_id);
 857                        if halt_dispatch {
 858                            halted_dispatch = true;
 859                            break;
 860                        }
 861                    }
 862                    self.actions
 863                        .get_mut(&type_id)
 864                        .unwrap()
 865                        .insert(name, handlers);
 866                }
 867
 868                self.cx.views.insert((window_id, *view_id), view);
 869
 870                if halted_dispatch {
 871                    break;
 872                }
 873            }
 874        }
 875
 876        if !halted_dispatch {
 877            self.dispatch_global_action_any(name, arg);
 878        }
 879
 880        self.flush_effects();
 881        halted_dispatch
 882    }
 883
 884    pub fn dispatch_global_action<T: 'static + Any>(&mut self, name: &str, arg: T) {
 885        self.dispatch_global_action_any(name, Box::new(arg).as_ref());
 886    }
 887
 888    fn dispatch_global_action_any(&mut self, name: &str, arg: &dyn Any) {
 889        if let Some((name, mut handlers)) = self.global_actions.remove_entry(name) {
 890            self.pending_flushes += 1;
 891            for handler in handlers.iter_mut().rev() {
 892                handler(arg, self);
 893            }
 894            self.global_actions.insert(name, handlers);
 895            self.flush_effects();
 896        }
 897    }
 898
 899    pub fn add_bindings<T: IntoIterator<Item = keymap::Binding>>(&mut self, bindings: T) {
 900        self.keystroke_matcher.add_bindings(bindings);
 901    }
 902
 903    pub fn dispatch_keystroke(
 904        &mut self,
 905        window_id: usize,
 906        responder_chain: Vec<usize>,
 907        keystroke: &Keystroke,
 908    ) -> Result<bool> {
 909        let mut context_chain = Vec::new();
 910        let mut context = keymap::Context::default();
 911        for view_id in &responder_chain {
 912            if let Some(view) = self.cx.views.get(&(window_id, *view_id)) {
 913                context.extend(view.keymap_context(self.as_ref()));
 914                context_chain.push(context.clone());
 915            } else {
 916                return Err(anyhow!(
 917                    "View {} in responder chain does not exist",
 918                    view_id
 919                ));
 920            }
 921        }
 922
 923        let mut pending = false;
 924        for (i, cx) in context_chain.iter().enumerate().rev() {
 925            match self
 926                .keystroke_matcher
 927                .push_keystroke(keystroke.clone(), responder_chain[i], cx)
 928            {
 929                MatchResult::None => {}
 930                MatchResult::Pending => pending = true,
 931                MatchResult::Action { name, arg } => {
 932                    if self.dispatch_action_any(
 933                        window_id,
 934                        &responder_chain[0..=i],
 935                        &name,
 936                        arg.as_ref().map(|arg| arg.as_ref()).unwrap_or(&()),
 937                    ) {
 938                        return Ok(true);
 939                    }
 940                }
 941            }
 942        }
 943
 944        Ok(pending)
 945    }
 946
 947    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 948    where
 949        T: Entity,
 950        F: FnOnce(&mut ModelContext<T>) -> T,
 951    {
 952        self.pending_flushes += 1;
 953        let model_id = post_inc(&mut self.next_entity_id);
 954        let handle = ModelHandle::new(model_id, &self.cx.ref_counts);
 955        let mut cx = ModelContext::new(self, model_id);
 956        let model = build_model(&mut cx);
 957        self.cx.models.insert(model_id, Box::new(model));
 958        self.flush_effects();
 959        handle
 960    }
 961
 962    pub fn add_window<T, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<T>)
 963    where
 964        T: View,
 965        F: FnOnce(&mut ViewContext<T>) -> T,
 966    {
 967        self.pending_flushes += 1;
 968        let window_id = post_inc(&mut self.next_window_id);
 969        let root_view = self.add_view(window_id, build_root_view);
 970
 971        self.cx.windows.insert(
 972            window_id,
 973            Window {
 974                root_view: root_view.clone().into(),
 975                focused_view_id: root_view.id(),
 976                invalidation: None,
 977            },
 978        );
 979        self.open_platform_window(window_id);
 980        root_view.update(self, |view, cx| {
 981            view.on_focus(cx);
 982            cx.notify();
 983        });
 984        self.flush_effects();
 985
 986        (window_id, root_view)
 987    }
 988
 989    pub fn remove_window(&mut self, window_id: usize) {
 990        self.cx.windows.remove(&window_id);
 991        self.presenters_and_platform_windows.remove(&window_id);
 992        self.remove_dropped_entities();
 993    }
 994
 995    fn open_platform_window(&mut self, window_id: usize) {
 996        let mut window = self.cx.platform.open_window(
 997            window_id,
 998            WindowOptions {
 999                bounds: RectF::new(vec2f(0., 0.), vec2f(1024., 768.)),
1000                title: "Zed".into(),
1001            },
1002            self.foreground.clone(),
1003        );
1004        let text_layout_cache = TextLayoutCache::new(self.cx.platform.fonts());
1005        let presenter = Rc::new(RefCell::new(Presenter::new(
1006            window_id,
1007            self.cx.font_cache.clone(),
1008            text_layout_cache,
1009            self.assets.clone(),
1010            self,
1011        )));
1012
1013        {
1014            let mut app = self.upgrade();
1015            let presenter = presenter.clone();
1016            window.on_event(Box::new(move |event| {
1017                app.update(|cx| {
1018                    if let Event::KeyDown { keystroke, .. } = &event {
1019                        if cx
1020                            .dispatch_keystroke(
1021                                window_id,
1022                                presenter.borrow().dispatch_path(cx.as_ref()),
1023                                keystroke,
1024                            )
1025                            .unwrap()
1026                        {
1027                            return;
1028                        }
1029                    }
1030
1031                    presenter.borrow_mut().dispatch_event(event, cx);
1032                })
1033            }));
1034        }
1035
1036        {
1037            let mut app = self.upgrade();
1038            let presenter = presenter.clone();
1039            window.on_resize(Box::new(move |window| {
1040                app.update(|cx| {
1041                    let scene = presenter.borrow_mut().build_scene(
1042                        window.size(),
1043                        window.scale_factor(),
1044                        cx,
1045                    );
1046                    window.present_scene(scene);
1047                })
1048            }));
1049        }
1050
1051        {
1052            let mut app = self.upgrade();
1053            window.on_close(Box::new(move || {
1054                app.update(|cx| cx.remove_window(window_id));
1055            }));
1056        }
1057
1058        self.presenters_and_platform_windows
1059            .insert(window_id, (presenter.clone(), window));
1060
1061        self.on_debug_elements(window_id, move |cx| {
1062            presenter.borrow().debug_elements(cx).unwrap()
1063        });
1064    }
1065
1066    pub fn add_view<T, F>(&mut self, window_id: usize, build_view: F) -> ViewHandle<T>
1067    where
1068        T: View,
1069        F: FnOnce(&mut ViewContext<T>) -> T,
1070    {
1071        self.add_option_view(window_id, |cx| Some(build_view(cx)))
1072            .unwrap()
1073    }
1074
1075    pub fn add_option_view<T, F>(
1076        &mut self,
1077        window_id: usize,
1078        build_view: F,
1079    ) -> Option<ViewHandle<T>>
1080    where
1081        T: View,
1082        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
1083    {
1084        let view_id = post_inc(&mut self.next_entity_id);
1085        self.pending_flushes += 1;
1086        let handle = ViewHandle::new(window_id, view_id, &self.cx.ref_counts);
1087        let mut cx = ViewContext::new(self, window_id, view_id);
1088        let handle = if let Some(view) = build_view(&mut cx) {
1089            self.cx.views.insert((window_id, view_id), Box::new(view));
1090            if let Some(window) = self.cx.windows.get_mut(&window_id) {
1091                window
1092                    .invalidation
1093                    .get_or_insert_with(Default::default)
1094                    .updated
1095                    .insert(view_id);
1096            }
1097            Some(handle)
1098        } else {
1099            None
1100        };
1101        self.flush_effects();
1102        handle
1103    }
1104
1105    fn remove_dropped_entities(&mut self) {
1106        loop {
1107            let (dropped_models, dropped_views, dropped_values) =
1108                self.cx.ref_counts.lock().take_dropped();
1109            if dropped_models.is_empty() && dropped_views.is_empty() && dropped_values.is_empty() {
1110                break;
1111            }
1112
1113            for model_id in dropped_models {
1114                self.subscriptions.remove(&model_id);
1115                self.model_observations.remove(&model_id);
1116                let mut model = self.cx.models.remove(&model_id).unwrap();
1117                model.release(self);
1118            }
1119
1120            for (window_id, view_id) in dropped_views {
1121                self.subscriptions.remove(&view_id);
1122                self.model_observations.remove(&view_id);
1123                let mut view = self.cx.views.remove(&(window_id, view_id)).unwrap();
1124                view.release(self);
1125                let change_focus_to = self.cx.windows.get_mut(&window_id).and_then(|window| {
1126                    window
1127                        .invalidation
1128                        .get_or_insert_with(Default::default)
1129                        .removed
1130                        .push(view_id);
1131                    if window.focused_view_id == view_id {
1132                        Some(window.root_view.id())
1133                    } else {
1134                        None
1135                    }
1136                });
1137
1138                if let Some(view_id) = change_focus_to {
1139                    self.focus(window_id, view_id);
1140                }
1141            }
1142
1143            let mut values = self.cx.values.write();
1144            for key in dropped_values {
1145                values.remove(&key);
1146            }
1147        }
1148    }
1149
1150    fn flush_effects(&mut self) {
1151        self.pending_flushes = self.pending_flushes.saturating_sub(1);
1152
1153        if !self.flushing_effects && self.pending_flushes == 0 {
1154            self.flushing_effects = true;
1155
1156            loop {
1157                if let Some(effect) = self.pending_effects.pop_front() {
1158                    match effect {
1159                        Effect::Event { entity_id, payload } => self.emit_event(entity_id, payload),
1160                        Effect::ModelNotification { model_id } => {
1161                            self.notify_model_observers(model_id)
1162                        }
1163                        Effect::ViewNotification { window_id, view_id } => {
1164                            self.notify_view_observers(window_id, view_id)
1165                        }
1166                        Effect::Focus { window_id, view_id } => {
1167                            self.focus(window_id, view_id);
1168                        }
1169                    }
1170                    self.remove_dropped_entities();
1171                } else {
1172                    self.remove_dropped_entities();
1173                    self.update_windows();
1174
1175                    if self.pending_effects.is_empty() {
1176                        self.flushing_effects = false;
1177                        break;
1178                    }
1179                }
1180            }
1181        }
1182    }
1183
1184    fn update_windows(&mut self) {
1185        let mut invalidations = HashMap::new();
1186        for (window_id, window) in &mut self.cx.windows {
1187            if let Some(invalidation) = window.invalidation.take() {
1188                invalidations.insert(*window_id, invalidation);
1189            }
1190        }
1191
1192        for (window_id, invalidation) in invalidations {
1193            if let Some((presenter, mut window)) =
1194                self.presenters_and_platform_windows.remove(&window_id)
1195            {
1196                {
1197                    let mut presenter = presenter.borrow_mut();
1198                    presenter.invalidate(invalidation, self.as_ref());
1199                    let scene = presenter.build_scene(window.size(), window.scale_factor(), self);
1200                    window.present_scene(scene);
1201                }
1202                self.presenters_and_platform_windows
1203                    .insert(window_id, (presenter, window));
1204            }
1205        }
1206    }
1207
1208    fn emit_event(&mut self, entity_id: usize, payload: Box<dyn Any>) {
1209        if let Some(subscriptions) = self.subscriptions.remove(&entity_id) {
1210            for mut subscription in subscriptions {
1211                let alive = match &mut subscription {
1212                    Subscription::FromModel { model_id, callback } => {
1213                        if let Some(mut model) = self.cx.models.remove(model_id) {
1214                            callback(model.as_any_mut(), payload.as_ref(), self, *model_id);
1215                            self.cx.models.insert(*model_id, model);
1216                            true
1217                        } else {
1218                            false
1219                        }
1220                    }
1221                    Subscription::FromView {
1222                        window_id,
1223                        view_id,
1224                        callback,
1225                    } => {
1226                        if let Some(mut view) = self.cx.views.remove(&(*window_id, *view_id)) {
1227                            callback(
1228                                view.as_any_mut(),
1229                                payload.as_ref(),
1230                                self,
1231                                *window_id,
1232                                *view_id,
1233                            );
1234                            self.cx.views.insert((*window_id, *view_id), view);
1235                            true
1236                        } else {
1237                            false
1238                        }
1239                    }
1240                };
1241
1242                if alive {
1243                    self.subscriptions
1244                        .entry(entity_id)
1245                        .or_default()
1246                        .push(subscription);
1247                }
1248            }
1249        }
1250    }
1251
1252    fn notify_model_observers(&mut self, observed_id: usize) {
1253        if let Some(observations) = self.model_observations.remove(&observed_id) {
1254            if self.cx.models.contains_key(&observed_id) {
1255                for mut observation in observations {
1256                    let alive = match &mut observation {
1257                        ModelObservation::FromModel { model_id, callback } => {
1258                            if let Some(mut model) = self.cx.models.remove(model_id) {
1259                                callback(model.as_any_mut(), observed_id, self, *model_id);
1260                                self.cx.models.insert(*model_id, model);
1261                                true
1262                            } else {
1263                                false
1264                            }
1265                        }
1266                        ModelObservation::FromView {
1267                            window_id,
1268                            view_id,
1269                            callback,
1270                        } => {
1271                            if let Some(mut view) = self.cx.views.remove(&(*window_id, *view_id)) {
1272                                callback(
1273                                    view.as_any_mut(),
1274                                    observed_id,
1275                                    self,
1276                                    *window_id,
1277                                    *view_id,
1278                                );
1279                                self.cx.views.insert((*window_id, *view_id), view);
1280                                true
1281                            } else {
1282                                false
1283                            }
1284                        }
1285                    };
1286
1287                    if alive {
1288                        self.model_observations
1289                            .entry(observed_id)
1290                            .or_default()
1291                            .push(observation);
1292                    }
1293                }
1294            }
1295        }
1296    }
1297
1298    fn notify_view_observers(&mut self, window_id: usize, view_id: usize) {
1299        if let Some(window) = self.cx.windows.get_mut(&window_id) {
1300            window
1301                .invalidation
1302                .get_or_insert_with(Default::default)
1303                .updated
1304                .insert(view_id);
1305        }
1306
1307        if let Some(observations) = self.view_observations.remove(&view_id) {
1308            if self.cx.views.contains_key(&(window_id, view_id)) {
1309                for mut observation in observations {
1310                    let alive = if let Some(mut view) = self
1311                        .cx
1312                        .views
1313                        .remove(&(observation.window_id, observation.view_id))
1314                    {
1315                        (observation.callback)(
1316                            view.as_any_mut(),
1317                            view_id,
1318                            window_id,
1319                            self,
1320                            observation.window_id,
1321                            observation.view_id,
1322                        );
1323                        self.cx
1324                            .views
1325                            .insert((observation.window_id, observation.view_id), view);
1326                        true
1327                    } else {
1328                        false
1329                    };
1330
1331                    if alive {
1332                        self.view_observations
1333                            .entry(view_id)
1334                            .or_default()
1335                            .push(observation);
1336                    }
1337                }
1338            }
1339        }
1340    }
1341
1342    fn focus(&mut self, window_id: usize, focused_id: usize) {
1343        if self
1344            .cx
1345            .windows
1346            .get(&window_id)
1347            .map(|w| w.focused_view_id)
1348            .map_or(false, |cur_focused| cur_focused == focused_id)
1349        {
1350            return;
1351        }
1352
1353        self.pending_flushes += 1;
1354
1355        let blurred_id = self.cx.windows.get_mut(&window_id).map(|window| {
1356            let blurred_id = window.focused_view_id;
1357            window.focused_view_id = focused_id;
1358            blurred_id
1359        });
1360
1361        if let Some(blurred_id) = blurred_id {
1362            if let Some(mut blurred_view) = self.cx.views.remove(&(window_id, blurred_id)) {
1363                blurred_view.on_blur(self, window_id, blurred_id);
1364                self.cx.views.insert((window_id, blurred_id), blurred_view);
1365            }
1366        }
1367
1368        if let Some(mut focused_view) = self.cx.views.remove(&(window_id, focused_id)) {
1369            focused_view.on_focus(self, window_id, focused_id);
1370            self.cx.views.insert((window_id, focused_id), focused_view);
1371        }
1372
1373        self.flush_effects();
1374    }
1375
1376    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
1377    where
1378        F: FnOnce(AsyncAppContext) -> Fut,
1379        Fut: 'static + Future<Output = T>,
1380        T: 'static,
1381    {
1382        let cx = self.to_async();
1383        self.foreground.spawn(f(cx))
1384    }
1385
1386    pub fn to_async(&self) -> AsyncAppContext {
1387        AsyncAppContext(self.weak_self.as_ref().unwrap().upgrade().unwrap())
1388    }
1389
1390    pub fn write_to_clipboard(&self, item: ClipboardItem) {
1391        self.cx.platform.write_to_clipboard(item);
1392    }
1393
1394    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
1395        self.cx.platform.read_from_clipboard()
1396    }
1397}
1398
1399impl ReadModel for MutableAppContext {
1400    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
1401        if let Some(model) = self.cx.models.get(&handle.model_id) {
1402            model
1403                .as_any()
1404                .downcast_ref()
1405                .expect("downcast is type safe")
1406        } else {
1407            panic!("circular model reference");
1408        }
1409    }
1410}
1411
1412impl UpdateModel for MutableAppContext {
1413    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
1414    where
1415        T: Entity,
1416        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
1417    {
1418        if let Some(mut model) = self.cx.models.remove(&handle.model_id) {
1419            self.pending_flushes += 1;
1420            let mut cx = ModelContext::new(self, handle.model_id);
1421            let result = update(
1422                model
1423                    .as_any_mut()
1424                    .downcast_mut()
1425                    .expect("downcast is type safe"),
1426                &mut cx,
1427            );
1428            self.cx.models.insert(handle.model_id, model);
1429            self.flush_effects();
1430            result
1431        } else {
1432            panic!("circular model update");
1433        }
1434    }
1435}
1436
1437impl ReadView for MutableAppContext {
1438    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
1439        if let Some(view) = self.cx.views.get(&(handle.window_id, handle.view_id)) {
1440            view.as_any().downcast_ref().expect("downcast is type safe")
1441        } else {
1442            panic!("circular view reference");
1443        }
1444    }
1445}
1446
1447impl UpdateView for MutableAppContext {
1448    fn update_view<T, F, S>(&mut self, handle: &ViewHandle<T>, update: F) -> S
1449    where
1450        T: View,
1451        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
1452    {
1453        self.pending_flushes += 1;
1454        let mut view = self
1455            .cx
1456            .views
1457            .remove(&(handle.window_id, handle.view_id))
1458            .expect("circular view update");
1459
1460        let mut cx = ViewContext::new(self, handle.window_id, handle.view_id);
1461        let result = update(
1462            view.as_any_mut()
1463                .downcast_mut()
1464                .expect("downcast is type safe"),
1465            &mut cx,
1466        );
1467        self.cx
1468            .views
1469            .insert((handle.window_id, handle.view_id), view);
1470        self.flush_effects();
1471        result
1472    }
1473}
1474
1475impl AsRef<AppContext> for MutableAppContext {
1476    fn as_ref(&self) -> &AppContext {
1477        &self.cx
1478    }
1479}
1480
1481impl Deref for MutableAppContext {
1482    type Target = AppContext;
1483
1484    fn deref(&self) -> &Self::Target {
1485        &self.cx
1486    }
1487}
1488
1489pub struct AppContext {
1490    models: HashMap<usize, Box<dyn AnyModel>>,
1491    views: HashMap<(usize, usize), Box<dyn AnyView>>,
1492    windows: HashMap<usize, Window>,
1493    values: RwLock<HashMap<(TypeId, usize), Box<dyn Any>>>,
1494    background: Arc<executor::Background>,
1495    ref_counts: Arc<Mutex<RefCounts>>,
1496    font_cache: Arc<FontCache>,
1497    platform: Arc<dyn Platform>,
1498}
1499
1500impl AppContext {
1501    pub fn root_view_id(&self, window_id: usize) -> Option<usize> {
1502        self.windows
1503            .get(&window_id)
1504            .map(|window| window.root_view.id())
1505    }
1506
1507    pub fn focused_view_id(&self, window_id: usize) -> Option<usize> {
1508        self.windows
1509            .get(&window_id)
1510            .map(|window| window.focused_view_id)
1511    }
1512
1513    pub fn render_view(&self, window_id: usize, view_id: usize) -> Result<ElementBox> {
1514        self.views
1515            .get(&(window_id, view_id))
1516            .map(|v| v.render(self))
1517            .ok_or(anyhow!("view not found"))
1518    }
1519
1520    pub fn render_views(&self, window_id: usize) -> HashMap<usize, ElementBox> {
1521        self.views
1522            .iter()
1523            .filter_map(|((win_id, view_id), view)| {
1524                if *win_id == window_id {
1525                    Some((*view_id, view.render(self)))
1526                } else {
1527                    None
1528                }
1529            })
1530            .collect::<HashMap<_, ElementBox>>()
1531    }
1532
1533    pub fn background(&self) -> &Arc<executor::Background> {
1534        &self.background
1535    }
1536
1537    pub fn font_cache(&self) -> &Arc<FontCache> {
1538        &self.font_cache
1539    }
1540
1541    pub fn platform(&self) -> &Arc<dyn Platform> {
1542        &self.platform
1543    }
1544
1545    pub fn value<Tag: 'static, T: 'static + Default>(&self, id: usize) -> ValueHandle<T> {
1546        let key = (TypeId::of::<Tag>(), id);
1547        self.values
1548            .write()
1549            .entry(key)
1550            .or_insert_with(|| Box::new(T::default()));
1551        ValueHandle::new(TypeId::of::<Tag>(), id, &self.ref_counts)
1552    }
1553}
1554
1555impl ReadModel for AppContext {
1556    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
1557        if let Some(model) = self.models.get(&handle.model_id) {
1558            model
1559                .as_any()
1560                .downcast_ref()
1561                .expect("downcast should be type safe")
1562        } else {
1563            panic!("circular model reference");
1564        }
1565    }
1566}
1567
1568impl ReadView for AppContext {
1569    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
1570        if let Some(view) = self.views.get(&(handle.window_id, handle.view_id)) {
1571            view.as_any()
1572                .downcast_ref()
1573                .expect("downcast should be type safe")
1574        } else {
1575            panic!("circular view reference");
1576        }
1577    }
1578}
1579
1580struct Window {
1581    root_view: AnyViewHandle,
1582    focused_view_id: usize,
1583    invalidation: Option<WindowInvalidation>,
1584}
1585
1586#[derive(Default, Clone)]
1587pub struct WindowInvalidation {
1588    pub updated: HashSet<usize>,
1589    pub removed: Vec<usize>,
1590}
1591
1592pub enum Effect {
1593    Event {
1594        entity_id: usize,
1595        payload: Box<dyn Any>,
1596    },
1597    ModelNotification {
1598        model_id: usize,
1599    },
1600    ViewNotification {
1601        window_id: usize,
1602        view_id: usize,
1603    },
1604    Focus {
1605        window_id: usize,
1606        view_id: usize,
1607    },
1608}
1609
1610impl Debug for Effect {
1611    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1612        match self {
1613            Effect::Event { entity_id, .. } => f
1614                .debug_struct("Effect::Event")
1615                .field("entity_id", entity_id)
1616                .finish(),
1617            Effect::ModelNotification { model_id } => f
1618                .debug_struct("Effect::ModelNotification")
1619                .field("model_id", model_id)
1620                .finish(),
1621            Effect::ViewNotification { window_id, view_id } => f
1622                .debug_struct("Effect::ViewNotification")
1623                .field("window_id", window_id)
1624                .field("view_id", view_id)
1625                .finish(),
1626            Effect::Focus { window_id, view_id } => f
1627                .debug_struct("Effect::Focus")
1628                .field("window_id", window_id)
1629                .field("view_id", view_id)
1630                .finish(),
1631        }
1632    }
1633}
1634
1635pub trait AnyModel: Send + Sync {
1636    fn as_any(&self) -> &dyn Any;
1637    fn as_any_mut(&mut self) -> &mut dyn Any;
1638    fn release(&mut self, cx: &mut MutableAppContext);
1639}
1640
1641impl<T> AnyModel for T
1642where
1643    T: Entity,
1644{
1645    fn as_any(&self) -> &dyn Any {
1646        self
1647    }
1648
1649    fn as_any_mut(&mut self) -> &mut dyn Any {
1650        self
1651    }
1652
1653    fn release(&mut self, cx: &mut MutableAppContext) {
1654        self.release(cx);
1655    }
1656}
1657
1658pub trait AnyView: Send + Sync {
1659    fn as_any(&self) -> &dyn Any;
1660    fn as_any_mut(&mut self) -> &mut dyn Any;
1661    fn release(&mut self, cx: &mut MutableAppContext);
1662    fn ui_name(&self) -> &'static str;
1663    fn render<'a>(&self, cx: &AppContext) -> ElementBox;
1664    fn on_focus(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize);
1665    fn on_blur(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize);
1666    fn keymap_context(&self, cx: &AppContext) -> keymap::Context;
1667}
1668
1669impl<T> AnyView for T
1670where
1671    T: View,
1672{
1673    fn as_any(&self) -> &dyn Any {
1674        self
1675    }
1676
1677    fn as_any_mut(&mut self) -> &mut dyn Any {
1678        self
1679    }
1680
1681    fn release(&mut self, cx: &mut MutableAppContext) {
1682        self.release(cx);
1683    }
1684
1685    fn ui_name(&self) -> &'static str {
1686        T::ui_name()
1687    }
1688
1689    fn render<'a>(&self, cx: &AppContext) -> ElementBox {
1690        View::render(self, cx)
1691    }
1692
1693    fn on_focus(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize) {
1694        let mut cx = ViewContext::new(cx, window_id, view_id);
1695        View::on_focus(self, &mut cx);
1696    }
1697
1698    fn on_blur(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize) {
1699        let mut cx = ViewContext::new(cx, window_id, view_id);
1700        View::on_blur(self, &mut cx);
1701    }
1702
1703    fn keymap_context(&self, cx: &AppContext) -> keymap::Context {
1704        View::keymap_context(self, cx)
1705    }
1706}
1707
1708pub struct ModelContext<'a, T: ?Sized> {
1709    app: &'a mut MutableAppContext,
1710    model_id: usize,
1711    model_type: PhantomData<T>,
1712    halt_stream: bool,
1713}
1714
1715impl<'a, T: Entity> ModelContext<'a, T> {
1716    fn new(app: &'a mut MutableAppContext, model_id: usize) -> Self {
1717        Self {
1718            app,
1719            model_id,
1720            model_type: PhantomData,
1721            halt_stream: false,
1722        }
1723    }
1724
1725    pub fn background(&self) -> &Arc<executor::Background> {
1726        &self.app.cx.background
1727    }
1728
1729    pub fn halt_stream(&mut self) {
1730        self.halt_stream = true;
1731    }
1732
1733    pub fn model_id(&self) -> usize {
1734        self.model_id
1735    }
1736
1737    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
1738    where
1739        S: Entity,
1740        F: FnOnce(&mut ModelContext<S>) -> S,
1741    {
1742        self.app.add_model(build_model)
1743    }
1744
1745    pub fn subscribe<S: Entity, F>(&mut self, handle: &ModelHandle<S>, mut callback: F)
1746    where
1747        S::Event: 'static,
1748        F: 'static + FnMut(&mut T, &S::Event, &mut ModelContext<T>),
1749    {
1750        self.app
1751            .subscriptions
1752            .entry(handle.model_id)
1753            .or_default()
1754            .push(Subscription::FromModel {
1755                model_id: self.model_id,
1756                callback: Box::new(move |model, payload, app, model_id| {
1757                    let model = model.downcast_mut().expect("downcast is type safe");
1758                    let payload = payload.downcast_ref().expect("downcast is type safe");
1759                    let mut cx = ModelContext::new(app, model_id);
1760                    callback(model, payload, &mut cx);
1761                }),
1762            });
1763    }
1764
1765    pub fn emit(&mut self, payload: T::Event) {
1766        self.app.pending_effects.push_back(Effect::Event {
1767            entity_id: self.model_id,
1768            payload: Box::new(payload),
1769        });
1770    }
1771
1772    pub fn observe<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F)
1773    where
1774        S: Entity,
1775        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ModelContext<T>),
1776    {
1777        self.app
1778            .model_observations
1779            .entry(handle.model_id)
1780            .or_default()
1781            .push(ModelObservation::FromModel {
1782                model_id: self.model_id,
1783                callback: Box::new(move |model, observed_id, app, model_id| {
1784                    let model = model.downcast_mut().expect("downcast is type safe");
1785                    let observed = ModelHandle::new(observed_id, &app.cx.ref_counts);
1786                    let mut cx = ModelContext::new(app, model_id);
1787                    callback(model, observed, &mut cx);
1788                }),
1789            });
1790    }
1791
1792    pub fn notify(&mut self) {
1793        self.app
1794            .pending_effects
1795            .push_back(Effect::ModelNotification {
1796                model_id: self.model_id,
1797            });
1798    }
1799
1800    pub fn handle(&self) -> ModelHandle<T> {
1801        ModelHandle::new(self.model_id, &self.app.cx.ref_counts)
1802    }
1803
1804    pub fn spawn<F, Fut, S>(&self, f: F) -> Task<S>
1805    where
1806        F: FnOnce(ModelHandle<T>, AsyncAppContext) -> Fut,
1807        Fut: 'static + Future<Output = S>,
1808        S: 'static,
1809    {
1810        let handle = self.handle();
1811        self.app.spawn(|cx| f(handle, cx))
1812    }
1813
1814    pub fn spawn_weak<F, Fut, S>(&self, f: F) -> Task<S>
1815    where
1816        F: FnOnce(WeakModelHandle<T>, AsyncAppContext) -> Fut,
1817        Fut: 'static + Future<Output = S>,
1818        S: 'static,
1819    {
1820        let handle = self.handle().downgrade();
1821        self.app.spawn(|cx| f(handle, cx))
1822    }
1823}
1824
1825impl<M> AsRef<AppContext> for ModelContext<'_, M> {
1826    fn as_ref(&self) -> &AppContext {
1827        &self.app.cx
1828    }
1829}
1830
1831impl<M> AsMut<MutableAppContext> for ModelContext<'_, M> {
1832    fn as_mut(&mut self) -> &mut MutableAppContext {
1833        self.app
1834    }
1835}
1836
1837impl<M> ReadModel for ModelContext<'_, M> {
1838    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
1839        self.app.read_model(handle)
1840    }
1841}
1842
1843impl<M> UpdateModel for ModelContext<'_, M> {
1844    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
1845    where
1846        T: Entity,
1847        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
1848    {
1849        self.app.update_model(handle, update)
1850    }
1851}
1852
1853impl<M> Deref for ModelContext<'_, M> {
1854    type Target = MutableAppContext;
1855
1856    fn deref(&self) -> &Self::Target {
1857        &self.app
1858    }
1859}
1860
1861impl<M> DerefMut for ModelContext<'_, M> {
1862    fn deref_mut(&mut self) -> &mut Self::Target {
1863        &mut self.app
1864    }
1865}
1866
1867pub struct ViewContext<'a, T: ?Sized> {
1868    app: &'a mut MutableAppContext,
1869    window_id: usize,
1870    view_id: usize,
1871    view_type: PhantomData<T>,
1872    halt_action_dispatch: bool,
1873}
1874
1875impl<'a, T: View> ViewContext<'a, T> {
1876    fn new(app: &'a mut MutableAppContext, window_id: usize, view_id: usize) -> Self {
1877        Self {
1878            app,
1879            window_id,
1880            view_id,
1881            view_type: PhantomData,
1882            halt_action_dispatch: true,
1883        }
1884    }
1885
1886    pub fn handle(&self) -> ViewHandle<T> {
1887        ViewHandle::new(self.window_id, self.view_id, &self.app.cx.ref_counts)
1888    }
1889
1890    pub fn window_id(&self) -> usize {
1891        self.window_id
1892    }
1893
1894    pub fn view_id(&self) -> usize {
1895        self.view_id
1896    }
1897
1898    pub fn foreground(&self) -> &Rc<executor::Foreground> {
1899        self.app.foreground()
1900    }
1901
1902    pub fn background_executor(&self) -> &Arc<executor::Background> {
1903        &self.app.cx.background
1904    }
1905
1906    pub fn platform(&self) -> Arc<dyn Platform> {
1907        self.app.platform()
1908    }
1909
1910    pub fn prompt<F>(&self, level: PromptLevel, msg: &str, answers: &[&str], done_fn: F)
1911    where
1912        F: 'static + FnOnce(usize, &mut MutableAppContext),
1913    {
1914        self.app
1915            .prompt(self.window_id, level, msg, answers, done_fn)
1916    }
1917
1918    pub fn prompt_for_paths<F>(&self, options: PathPromptOptions, done_fn: F)
1919    where
1920        F: 'static + FnOnce(Option<Vec<PathBuf>>, &mut MutableAppContext),
1921    {
1922        self.app.prompt_for_paths(options, done_fn)
1923    }
1924
1925    pub fn prompt_for_new_path<F>(&self, directory: &Path, done_fn: F)
1926    where
1927        F: 'static + FnOnce(Option<PathBuf>, &mut MutableAppContext),
1928    {
1929        self.app.prompt_for_new_path(directory, done_fn)
1930    }
1931
1932    pub fn debug_elements(&self) -> crate::json::Value {
1933        self.app.debug_elements(self.window_id).unwrap()
1934    }
1935
1936    pub fn focus<S>(&mut self, handle: S)
1937    where
1938        S: Into<AnyViewHandle>,
1939    {
1940        let handle = handle.into();
1941        self.app.pending_effects.push_back(Effect::Focus {
1942            window_id: handle.window_id,
1943            view_id: handle.view_id,
1944        });
1945    }
1946
1947    pub fn focus_self(&mut self) {
1948        self.app.pending_effects.push_back(Effect::Focus {
1949            window_id: self.window_id,
1950            view_id: self.view_id,
1951        });
1952    }
1953
1954    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
1955    where
1956        S: Entity,
1957        F: FnOnce(&mut ModelContext<S>) -> S,
1958    {
1959        self.app.add_model(build_model)
1960    }
1961
1962    pub fn add_view<S, F>(&mut self, build_view: F) -> ViewHandle<S>
1963    where
1964        S: View,
1965        F: FnOnce(&mut ViewContext<S>) -> S,
1966    {
1967        self.app.add_view(self.window_id, build_view)
1968    }
1969
1970    pub fn add_option_view<S, F>(&mut self, build_view: F) -> Option<ViewHandle<S>>
1971    where
1972        S: View,
1973        F: FnOnce(&mut ViewContext<S>) -> Option<S>,
1974    {
1975        self.app.add_option_view(self.window_id, build_view)
1976    }
1977
1978    pub fn subscribe_to_model<E, F>(&mut self, handle: &ModelHandle<E>, mut callback: F)
1979    where
1980        E: Entity,
1981        E::Event: 'static,
1982        F: 'static + FnMut(&mut T, ModelHandle<E>, &E::Event, &mut ViewContext<T>),
1983    {
1984        let emitter_handle = handle.downgrade();
1985        self.subscribe(handle, move |model, payload, cx| {
1986            if let Some(emitter_handle) = emitter_handle.upgrade(cx.as_ref()) {
1987                callback(model, emitter_handle, payload, cx);
1988            }
1989        });
1990    }
1991
1992    pub fn subscribe_to_view<V, F>(&mut self, handle: &ViewHandle<V>, mut callback: F)
1993    where
1994        V: View,
1995        V::Event: 'static,
1996        F: 'static + FnMut(&mut T, ViewHandle<V>, &V::Event, &mut ViewContext<T>),
1997    {
1998        let emitter_handle = handle.downgrade();
1999        self.subscribe(handle, move |view, payload, cx| {
2000            if let Some(emitter_handle) = emitter_handle.upgrade(cx.as_ref()) {
2001                callback(view, emitter_handle, payload, cx);
2002            }
2003        });
2004    }
2005
2006    pub fn subscribe<E, F>(&mut self, handle: &impl Handle<E>, mut callback: F)
2007    where
2008        E: Entity,
2009        E::Event: 'static,
2010        F: 'static + FnMut(&mut T, &E::Event, &mut ViewContext<T>),
2011    {
2012        self.app
2013            .subscriptions
2014            .entry(handle.id())
2015            .or_default()
2016            .push(Subscription::FromView {
2017                window_id: self.window_id,
2018                view_id: self.view_id,
2019                callback: Box::new(move |entity, payload, app, window_id, view_id| {
2020                    let entity = entity.downcast_mut().expect("downcast is type safe");
2021                    let payload = payload.downcast_ref().expect("downcast is type safe");
2022                    let mut cx = ViewContext::new(app, window_id, view_id);
2023                    callback(entity, payload, &mut cx);
2024                }),
2025            });
2026    }
2027
2028    pub fn emit(&mut self, payload: T::Event) {
2029        self.app.pending_effects.push_back(Effect::Event {
2030            entity_id: self.view_id,
2031            payload: Box::new(payload),
2032        });
2033    }
2034
2035    pub fn observe_model<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F)
2036    where
2037        S: Entity,
2038        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ViewContext<T>),
2039    {
2040        self.app
2041            .model_observations
2042            .entry(handle.id())
2043            .or_default()
2044            .push(ModelObservation::FromView {
2045                window_id: self.window_id,
2046                view_id: self.view_id,
2047                callback: Box::new(move |view, observed_id, app, window_id, view_id| {
2048                    let view = view.downcast_mut().expect("downcast is type safe");
2049                    let observed = ModelHandle::new(observed_id, &app.cx.ref_counts);
2050                    let mut cx = ViewContext::new(app, window_id, view_id);
2051                    callback(view, observed, &mut cx);
2052                }),
2053            });
2054    }
2055
2056    pub fn observe_view<S, F>(&mut self, handle: &ViewHandle<S>, mut callback: F)
2057    where
2058        S: View,
2059        F: 'static + FnMut(&mut T, ViewHandle<S>, &mut ViewContext<T>),
2060    {
2061        self.app
2062            .view_observations
2063            .entry(handle.id())
2064            .or_default()
2065            .push(ViewObservation {
2066                window_id: self.window_id,
2067                view_id: self.view_id,
2068                callback: Box::new(
2069                    move |view,
2070                          observed_view_id,
2071                          observed_window_id,
2072                          app,
2073                          observing_window_id,
2074                          observing_view_id| {
2075                        let view = view.downcast_mut().expect("downcast is type safe");
2076                        let observed_handle = ViewHandle::new(
2077                            observed_view_id,
2078                            observed_window_id,
2079                            &app.cx.ref_counts,
2080                        );
2081                        let mut cx = ViewContext::new(app, observing_window_id, observing_view_id);
2082                        callback(view, observed_handle, &mut cx);
2083                    },
2084                ),
2085            });
2086    }
2087
2088    pub fn notify(&mut self) {
2089        self.app.notify_view(self.window_id, self.view_id);
2090    }
2091
2092    pub fn propagate_action(&mut self) {
2093        self.halt_action_dispatch = false;
2094    }
2095
2096    pub fn spawn<F, Fut, S>(&self, f: F) -> Task<S>
2097    where
2098        F: FnOnce(ViewHandle<T>, AsyncAppContext) -> Fut,
2099        Fut: 'static + Future<Output = S>,
2100        S: 'static,
2101    {
2102        let handle = self.handle();
2103        self.app.spawn(|cx| f(handle, cx))
2104    }
2105}
2106
2107impl AsRef<AppContext> for &AppContext {
2108    fn as_ref(&self) -> &AppContext {
2109        self
2110    }
2111}
2112
2113impl<M> AsRef<AppContext> for ViewContext<'_, M> {
2114    fn as_ref(&self) -> &AppContext {
2115        &self.app.cx
2116    }
2117}
2118
2119impl<M> Deref for ViewContext<'_, M> {
2120    type Target = MutableAppContext;
2121
2122    fn deref(&self) -> &Self::Target {
2123        &self.app
2124    }
2125}
2126
2127impl<M> DerefMut for ViewContext<'_, M> {
2128    fn deref_mut(&mut self) -> &mut Self::Target {
2129        &mut self.app
2130    }
2131}
2132
2133impl<M> AsMut<MutableAppContext> for ViewContext<'_, M> {
2134    fn as_mut(&mut self) -> &mut MutableAppContext {
2135        self.app
2136    }
2137}
2138
2139impl<V> ReadModel for ViewContext<'_, V> {
2140    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
2141        self.app.read_model(handle)
2142    }
2143}
2144
2145impl<V: View> UpdateModel for ViewContext<'_, V> {
2146    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
2147    where
2148        T: Entity,
2149        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
2150    {
2151        self.app.update_model(handle, update)
2152    }
2153}
2154
2155impl<V: View> ReadView for ViewContext<'_, V> {
2156    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
2157        self.app.read_view(handle)
2158    }
2159}
2160
2161impl<V: View> UpdateView for ViewContext<'_, V> {
2162    fn update_view<T, F, S>(&mut self, handle: &ViewHandle<T>, update: F) -> S
2163    where
2164        T: View,
2165        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
2166    {
2167        self.app.update_view(handle, update)
2168    }
2169}
2170
2171pub trait Handle<T> {
2172    fn id(&self) -> usize;
2173    fn location(&self) -> EntityLocation;
2174}
2175
2176#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
2177pub enum EntityLocation {
2178    Model(usize),
2179    View(usize, usize),
2180}
2181
2182pub struct ModelHandle<T> {
2183    model_id: usize,
2184    model_type: PhantomData<T>,
2185    ref_counts: Arc<Mutex<RefCounts>>,
2186}
2187
2188impl<T: Entity> ModelHandle<T> {
2189    fn new(model_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
2190        ref_counts.lock().inc_model(model_id);
2191        Self {
2192            model_id,
2193            model_type: PhantomData,
2194            ref_counts: ref_counts.clone(),
2195        }
2196    }
2197
2198    pub fn downgrade(&self) -> WeakModelHandle<T> {
2199        WeakModelHandle::new(self.model_id)
2200    }
2201
2202    pub fn id(&self) -> usize {
2203        self.model_id
2204    }
2205
2206    pub fn read<'a, C: ReadModel>(&self, cx: &'a C) -> &'a T {
2207        cx.read_model(self)
2208    }
2209
2210    pub fn read_with<'a, C, F, S>(&self, cx: &C, read: F) -> S
2211    where
2212        C: ReadModelWith,
2213        F: FnOnce(&T, &AppContext) -> S,
2214    {
2215        cx.read_model_with(self, read)
2216    }
2217
2218    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
2219    where
2220        C: UpdateModel,
2221        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
2222    {
2223        cx.update_model(self, update)
2224    }
2225
2226    pub fn condition(
2227        &self,
2228        cx: &TestAppContext,
2229        mut predicate: impl FnMut(&T, &AppContext) -> bool,
2230    ) -> impl Future<Output = ()> {
2231        let (tx, mut rx) = mpsc::channel(1024);
2232
2233        let mut cx = cx.cx.borrow_mut();
2234        self.update(&mut *cx, |_, cx| {
2235            cx.observe(self, {
2236                let mut tx = tx.clone();
2237                move |_, _, _| {
2238                    tx.blocking_send(()).ok();
2239                }
2240            });
2241            cx.subscribe(self, {
2242                let mut tx = tx.clone();
2243                move |_, _, _| {
2244                    tx.blocking_send(()).ok();
2245                }
2246            })
2247        });
2248
2249        let cx = cx.weak_self.as_ref().unwrap().upgrade().unwrap();
2250        let handle = self.downgrade();
2251        let duration = if std::env::var("CI").is_ok() {
2252            Duration::from_secs(5)
2253        } else {
2254            Duration::from_secs(1)
2255        };
2256
2257        async move {
2258            timeout(duration, async move {
2259                loop {
2260                    {
2261                        let cx = cx.borrow();
2262                        let cx = cx.as_ref();
2263                        if predicate(
2264                            handle
2265                                .upgrade(cx)
2266                                .expect("model dropped with pending condition")
2267                                .read(cx),
2268                            cx,
2269                        ) {
2270                            break;
2271                        }
2272                    }
2273
2274                    rx.recv()
2275                        .await
2276                        .expect("model dropped with pending condition");
2277                }
2278            })
2279            .await
2280            .expect("condition timed out");
2281        }
2282    }
2283}
2284
2285impl<T> Clone for ModelHandle<T> {
2286    fn clone(&self) -> Self {
2287        self.ref_counts.lock().inc_model(self.model_id);
2288        Self {
2289            model_id: self.model_id,
2290            model_type: PhantomData,
2291            ref_counts: self.ref_counts.clone(),
2292        }
2293    }
2294}
2295
2296impl<T> PartialEq for ModelHandle<T> {
2297    fn eq(&self, other: &Self) -> bool {
2298        self.model_id == other.model_id
2299    }
2300}
2301
2302impl<T> Eq for ModelHandle<T> {}
2303
2304impl<T> Hash for ModelHandle<T> {
2305    fn hash<H: Hasher>(&self, state: &mut H) {
2306        self.model_id.hash(state);
2307    }
2308}
2309
2310impl<T> std::borrow::Borrow<usize> for ModelHandle<T> {
2311    fn borrow(&self) -> &usize {
2312        &self.model_id
2313    }
2314}
2315
2316impl<T> Debug for ModelHandle<T> {
2317    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2318        f.debug_tuple(&format!("ModelHandle<{}>", type_name::<T>()))
2319            .field(&self.model_id)
2320            .finish()
2321    }
2322}
2323
2324unsafe impl<T> Send for ModelHandle<T> {}
2325unsafe impl<T> Sync for ModelHandle<T> {}
2326
2327impl<T> Drop for ModelHandle<T> {
2328    fn drop(&mut self) {
2329        self.ref_counts.lock().dec_model(self.model_id);
2330    }
2331}
2332
2333impl<T> Handle<T> for ModelHandle<T> {
2334    fn id(&self) -> usize {
2335        self.model_id
2336    }
2337
2338    fn location(&self) -> EntityLocation {
2339        EntityLocation::Model(self.model_id)
2340    }
2341}
2342
2343pub struct WeakModelHandle<T> {
2344    model_id: usize,
2345    model_type: PhantomData<T>,
2346}
2347
2348impl<T: Entity> WeakModelHandle<T> {
2349    fn new(model_id: usize) -> Self {
2350        Self {
2351            model_id,
2352            model_type: PhantomData,
2353        }
2354    }
2355
2356    pub fn upgrade(&self, cx: impl AsRef<AppContext>) -> Option<ModelHandle<T>> {
2357        let cx = cx.as_ref();
2358        if cx.models.contains_key(&self.model_id) {
2359            Some(ModelHandle::new(self.model_id, &cx.ref_counts))
2360        } else {
2361            None
2362        }
2363    }
2364}
2365
2366impl<T> Hash for WeakModelHandle<T> {
2367    fn hash<H: Hasher>(&self, state: &mut H) {
2368        self.model_id.hash(state)
2369    }
2370}
2371
2372impl<T> PartialEq for WeakModelHandle<T> {
2373    fn eq(&self, other: &Self) -> bool {
2374        self.model_id == other.model_id
2375    }
2376}
2377
2378impl<T> Eq for WeakModelHandle<T> {}
2379
2380impl<T> Clone for WeakModelHandle<T> {
2381    fn clone(&self) -> Self {
2382        Self {
2383            model_id: self.model_id,
2384            model_type: PhantomData,
2385        }
2386    }
2387}
2388
2389pub struct ViewHandle<T> {
2390    window_id: usize,
2391    view_id: usize,
2392    view_type: PhantomData<T>,
2393    ref_counts: Arc<Mutex<RefCounts>>,
2394}
2395
2396impl<T: View> ViewHandle<T> {
2397    fn new(window_id: usize, view_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
2398        ref_counts.lock().inc_view(window_id, view_id);
2399        Self {
2400            window_id,
2401            view_id,
2402            view_type: PhantomData,
2403            ref_counts: ref_counts.clone(),
2404        }
2405    }
2406
2407    pub fn downgrade(&self) -> WeakViewHandle<T> {
2408        WeakViewHandle::new(self.window_id, self.view_id)
2409    }
2410
2411    pub fn window_id(&self) -> usize {
2412        self.window_id
2413    }
2414
2415    pub fn id(&self) -> usize {
2416        self.view_id
2417    }
2418
2419    pub fn read<'a, C: ReadView>(&self, cx: &'a C) -> &'a T {
2420        cx.read_view(self)
2421    }
2422
2423    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
2424    where
2425        C: ReadViewWith,
2426        F: FnOnce(&T, &AppContext) -> S,
2427    {
2428        cx.read_view_with(self, read)
2429    }
2430
2431    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
2432    where
2433        C: UpdateView,
2434        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
2435    {
2436        cx.update_view(self, update)
2437    }
2438
2439    pub fn is_focused(&self, cx: &AppContext) -> bool {
2440        cx.focused_view_id(self.window_id)
2441            .map_or(false, |focused_id| focused_id == self.view_id)
2442    }
2443
2444    pub fn condition(
2445        &self,
2446        cx: &TestAppContext,
2447        mut predicate: impl FnMut(&T, &AppContext) -> bool,
2448    ) -> impl Future<Output = ()> {
2449        let (tx, mut rx) = mpsc::channel(1024);
2450
2451        let mut cx = cx.cx.borrow_mut();
2452        self.update(&mut *cx, |_, cx| {
2453            cx.observe_view(self, {
2454                let mut tx = tx.clone();
2455                move |_, _, _| {
2456                    tx.blocking_send(()).ok();
2457                }
2458            });
2459
2460            cx.subscribe(self, {
2461                let mut tx = tx.clone();
2462                move |_, _, _| {
2463                    tx.blocking_send(()).ok();
2464                }
2465            })
2466        });
2467
2468        let cx = cx.weak_self.as_ref().unwrap().upgrade().unwrap();
2469        let handle = self.downgrade();
2470        let duration = if std::env::var("CI").is_ok() {
2471            Duration::from_secs(2)
2472        } else {
2473            Duration::from_millis(500)
2474        };
2475
2476        async move {
2477            timeout(duration, async move {
2478                loop {
2479                    {
2480                        let cx = cx.borrow();
2481                        let cx = cx.as_ref();
2482                        if predicate(
2483                            handle
2484                                .upgrade(cx)
2485                                .expect("view dropped with pending condition")
2486                                .read(cx),
2487                            cx,
2488                        ) {
2489                            break;
2490                        }
2491                    }
2492
2493                    rx.recv()
2494                        .await
2495                        .expect("view dropped with pending condition");
2496                }
2497            })
2498            .await
2499            .expect("condition timed out");
2500        }
2501    }
2502}
2503
2504impl<T> Clone for ViewHandle<T> {
2505    fn clone(&self) -> Self {
2506        self.ref_counts
2507            .lock()
2508            .inc_view(self.window_id, self.view_id);
2509        Self {
2510            window_id: self.window_id,
2511            view_id: self.view_id,
2512            view_type: PhantomData,
2513            ref_counts: self.ref_counts.clone(),
2514        }
2515    }
2516}
2517
2518impl<T> PartialEq for ViewHandle<T> {
2519    fn eq(&self, other: &Self) -> bool {
2520        self.window_id == other.window_id && self.view_id == other.view_id
2521    }
2522}
2523
2524impl<T> Eq for ViewHandle<T> {}
2525
2526impl<T> Debug for ViewHandle<T> {
2527    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2528        f.debug_struct(&format!("ViewHandle<{}>", type_name::<T>()))
2529            .field("window_id", &self.window_id)
2530            .field("view_id", &self.view_id)
2531            .finish()
2532    }
2533}
2534
2535impl<T> Drop for ViewHandle<T> {
2536    fn drop(&mut self) {
2537        self.ref_counts
2538            .lock()
2539            .dec_view(self.window_id, self.view_id);
2540    }
2541}
2542
2543impl<T> Handle<T> for ViewHandle<T> {
2544    fn id(&self) -> usize {
2545        self.view_id
2546    }
2547
2548    fn location(&self) -> EntityLocation {
2549        EntityLocation::View(self.window_id, self.view_id)
2550    }
2551}
2552
2553pub struct AnyViewHandle {
2554    window_id: usize,
2555    view_id: usize,
2556    view_type: TypeId,
2557    ref_counts: Arc<Mutex<RefCounts>>,
2558}
2559
2560impl AnyViewHandle {
2561    pub fn id(&self) -> usize {
2562        self.view_id
2563    }
2564
2565    pub fn is<T: 'static>(&self) -> bool {
2566        TypeId::of::<T>() == self.view_type
2567    }
2568
2569    pub fn downcast<T: View>(self) -> Option<ViewHandle<T>> {
2570        if self.is::<T>() {
2571            let result = Some(ViewHandle {
2572                window_id: self.window_id,
2573                view_id: self.view_id,
2574                ref_counts: self.ref_counts.clone(),
2575                view_type: PhantomData,
2576            });
2577            unsafe {
2578                Arc::decrement_strong_count(&self.ref_counts);
2579            }
2580            std::mem::forget(self);
2581            result
2582        } else {
2583            None
2584        }
2585    }
2586}
2587
2588impl Clone for AnyViewHandle {
2589    fn clone(&self) -> Self {
2590        self.ref_counts
2591            .lock()
2592            .inc_view(self.window_id, self.view_id);
2593        Self {
2594            window_id: self.window_id,
2595            view_id: self.view_id,
2596            view_type: self.view_type,
2597            ref_counts: self.ref_counts.clone(),
2598        }
2599    }
2600}
2601
2602impl<T: View> From<&ViewHandle<T>> for AnyViewHandle {
2603    fn from(handle: &ViewHandle<T>) -> Self {
2604        handle
2605            .ref_counts
2606            .lock()
2607            .inc_view(handle.window_id, handle.view_id);
2608        AnyViewHandle {
2609            window_id: handle.window_id,
2610            view_id: handle.view_id,
2611            view_type: TypeId::of::<T>(),
2612            ref_counts: handle.ref_counts.clone(),
2613        }
2614    }
2615}
2616
2617impl<T: View> From<ViewHandle<T>> for AnyViewHandle {
2618    fn from(handle: ViewHandle<T>) -> Self {
2619        let any_handle = AnyViewHandle {
2620            window_id: handle.window_id,
2621            view_id: handle.view_id,
2622            view_type: TypeId::of::<T>(),
2623            ref_counts: handle.ref_counts.clone(),
2624        };
2625        unsafe {
2626            Arc::decrement_strong_count(&handle.ref_counts);
2627        }
2628        std::mem::forget(handle);
2629        any_handle
2630    }
2631}
2632
2633impl Drop for AnyViewHandle {
2634    fn drop(&mut self) {
2635        self.ref_counts
2636            .lock()
2637            .dec_view(self.window_id, self.view_id);
2638    }
2639}
2640
2641pub struct AnyModelHandle {
2642    model_id: usize,
2643    ref_counts: Arc<Mutex<RefCounts>>,
2644}
2645
2646impl<T: Entity> From<ModelHandle<T>> for AnyModelHandle {
2647    fn from(handle: ModelHandle<T>) -> Self {
2648        handle.ref_counts.lock().inc_model(handle.model_id);
2649        Self {
2650            model_id: handle.model_id,
2651            ref_counts: handle.ref_counts.clone(),
2652        }
2653    }
2654}
2655
2656impl Drop for AnyModelHandle {
2657    fn drop(&mut self) {
2658        self.ref_counts.lock().dec_model(self.model_id);
2659    }
2660}
2661pub struct WeakViewHandle<T> {
2662    window_id: usize,
2663    view_id: usize,
2664    view_type: PhantomData<T>,
2665}
2666
2667impl<T: View> WeakViewHandle<T> {
2668    fn new(window_id: usize, view_id: usize) -> Self {
2669        Self {
2670            window_id,
2671            view_id,
2672            view_type: PhantomData,
2673        }
2674    }
2675
2676    pub fn upgrade(&self, cx: &AppContext) -> Option<ViewHandle<T>> {
2677        if cx.ref_counts.lock().is_entity_alive(self.view_id) {
2678            Some(ViewHandle::new(
2679                self.window_id,
2680                self.view_id,
2681                &cx.ref_counts,
2682            ))
2683        } else {
2684            None
2685        }
2686    }
2687}
2688
2689impl<T> Clone for WeakViewHandle<T> {
2690    fn clone(&self) -> Self {
2691        Self {
2692            window_id: self.window_id,
2693            view_id: self.view_id,
2694            view_type: PhantomData,
2695        }
2696    }
2697}
2698
2699pub struct ValueHandle<T> {
2700    value_type: PhantomData<T>,
2701    tag_type_id: TypeId,
2702    id: usize,
2703    ref_counts: Weak<Mutex<RefCounts>>,
2704}
2705
2706impl<T: 'static> ValueHandle<T> {
2707    fn new(tag_type_id: TypeId, id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
2708        ref_counts.lock().inc_value(tag_type_id, id);
2709        Self {
2710            value_type: PhantomData,
2711            tag_type_id,
2712            id,
2713            ref_counts: Arc::downgrade(ref_counts),
2714        }
2715    }
2716
2717    pub fn read<R>(&self, cx: &AppContext, f: impl FnOnce(&T) -> R) -> R {
2718        f(cx.values
2719            .read()
2720            .get(&(self.tag_type_id, self.id))
2721            .unwrap()
2722            .downcast_ref()
2723            .unwrap())
2724    }
2725
2726    pub fn update<R>(
2727        &self,
2728        cx: &mut EventContext,
2729        f: impl FnOnce(&mut T, &mut EventContext) -> R,
2730    ) -> R {
2731        let mut value = cx
2732            .app
2733            .cx
2734            .values
2735            .write()
2736            .remove(&(self.tag_type_id, self.id))
2737            .unwrap();
2738        let result = f(value.downcast_mut().unwrap(), cx);
2739        cx.app
2740            .cx
2741            .values
2742            .write()
2743            .insert((self.tag_type_id, self.id), value);
2744        result
2745    }
2746}
2747
2748impl<T> Drop for ValueHandle<T> {
2749    fn drop(&mut self) {
2750        if let Some(ref_counts) = self.ref_counts.upgrade() {
2751            ref_counts.lock().dec_value(self.tag_type_id, self.id);
2752        }
2753    }
2754}
2755
2756#[derive(Default)]
2757struct RefCounts {
2758    entity_counts: HashMap<usize, usize>,
2759    value_counts: HashMap<(TypeId, usize), usize>,
2760    dropped_models: HashSet<usize>,
2761    dropped_views: HashSet<(usize, usize)>,
2762    dropped_values: HashSet<(TypeId, usize)>,
2763}
2764
2765impl RefCounts {
2766    fn inc_model(&mut self, model_id: usize) {
2767        match self.entity_counts.entry(model_id) {
2768            Entry::Occupied(mut entry) => *entry.get_mut() += 1,
2769            Entry::Vacant(entry) => {
2770                entry.insert(1);
2771                self.dropped_models.remove(&model_id);
2772            }
2773        }
2774    }
2775
2776    fn inc_view(&mut self, window_id: usize, view_id: usize) {
2777        match self.entity_counts.entry(view_id) {
2778            Entry::Occupied(mut entry) => *entry.get_mut() += 1,
2779            Entry::Vacant(entry) => {
2780                entry.insert(1);
2781                self.dropped_views.remove(&(window_id, view_id));
2782            }
2783        }
2784    }
2785
2786    fn inc_value(&mut self, tag_type_id: TypeId, id: usize) {
2787        *self.value_counts.entry((tag_type_id, id)).or_insert(0) += 1;
2788    }
2789
2790    fn dec_model(&mut self, model_id: usize) {
2791        let count = self.entity_counts.get_mut(&model_id).unwrap();
2792        *count -= 1;
2793        if *count == 0 {
2794            self.entity_counts.remove(&model_id);
2795            self.dropped_models.insert(model_id);
2796        }
2797    }
2798
2799    fn dec_view(&mut self, window_id: usize, view_id: usize) {
2800        let count = self.entity_counts.get_mut(&view_id).unwrap();
2801        *count -= 1;
2802        if *count == 0 {
2803            self.entity_counts.remove(&view_id);
2804            self.dropped_views.insert((window_id, view_id));
2805        }
2806    }
2807
2808    fn dec_value(&mut self, tag_type_id: TypeId, id: usize) {
2809        let key = (tag_type_id, id);
2810        let count = self.value_counts.get_mut(&key).unwrap();
2811        *count -= 1;
2812        if *count == 0 {
2813            self.value_counts.remove(&key);
2814            self.dropped_values.insert(key);
2815        }
2816    }
2817
2818    fn is_entity_alive(&self, entity_id: usize) -> bool {
2819        self.entity_counts.contains_key(&entity_id)
2820    }
2821
2822    fn take_dropped(
2823        &mut self,
2824    ) -> (
2825        HashSet<usize>,
2826        HashSet<(usize, usize)>,
2827        HashSet<(TypeId, usize)>,
2828    ) {
2829        let mut dropped_models = HashSet::new();
2830        let mut dropped_views = HashSet::new();
2831        let mut dropped_values = HashSet::new();
2832        std::mem::swap(&mut self.dropped_models, &mut dropped_models);
2833        std::mem::swap(&mut self.dropped_views, &mut dropped_views);
2834        std::mem::swap(&mut self.dropped_values, &mut dropped_values);
2835        (dropped_models, dropped_views, dropped_values)
2836    }
2837}
2838
2839enum Subscription {
2840    FromModel {
2841        model_id: usize,
2842        callback: Box<dyn FnMut(&mut dyn Any, &dyn Any, &mut MutableAppContext, usize)>,
2843    },
2844    FromView {
2845        window_id: usize,
2846        view_id: usize,
2847        callback: Box<dyn FnMut(&mut dyn Any, &dyn Any, &mut MutableAppContext, usize, usize)>,
2848    },
2849}
2850
2851enum ModelObservation {
2852    FromModel {
2853        model_id: usize,
2854        callback: Box<dyn FnMut(&mut dyn Any, usize, &mut MutableAppContext, usize)>,
2855    },
2856    FromView {
2857        window_id: usize,
2858        view_id: usize,
2859        callback: Box<dyn FnMut(&mut dyn Any, usize, &mut MutableAppContext, usize, usize)>,
2860    },
2861}
2862
2863struct ViewObservation {
2864    window_id: usize,
2865    view_id: usize,
2866    callback: Box<dyn FnMut(&mut dyn Any, usize, usize, &mut MutableAppContext, usize, usize)>,
2867}
2868
2869#[cfg(test)]
2870mod tests {
2871    use super::*;
2872    use crate::elements::*;
2873    use smol::future::poll_once;
2874    use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
2875
2876    #[crate::test(self)]
2877    fn test_model_handles(cx: &mut MutableAppContext) {
2878        struct Model {
2879            other: Option<ModelHandle<Model>>,
2880            events: Vec<String>,
2881        }
2882
2883        impl Entity for Model {
2884            type Event = usize;
2885        }
2886
2887        impl Model {
2888            fn new(other: Option<ModelHandle<Self>>, cx: &mut ModelContext<Self>) -> Self {
2889                if let Some(other) = other.as_ref() {
2890                    cx.observe(other, |me, _, _| {
2891                        me.events.push("notified".into());
2892                    });
2893                    cx.subscribe(other, |me, event, _| {
2894                        me.events.push(format!("observed event {}", event));
2895                    });
2896                }
2897
2898                Self {
2899                    other,
2900                    events: Vec::new(),
2901                }
2902            }
2903        }
2904
2905        let handle_1 = cx.add_model(|cx| Model::new(None, cx));
2906        let handle_2 = cx.add_model(|cx| Model::new(Some(handle_1.clone()), cx));
2907        assert_eq!(cx.cx.models.len(), 2);
2908
2909        handle_1.update(cx, |model, cx| {
2910            model.events.push("updated".into());
2911            cx.emit(1);
2912            cx.notify();
2913            cx.emit(2);
2914        });
2915        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
2916        assert_eq!(
2917            handle_2.read(cx).events,
2918            vec![
2919                "observed event 1".to_string(),
2920                "notified".to_string(),
2921                "observed event 2".to_string(),
2922            ]
2923        );
2924
2925        handle_2.update(cx, |model, _| {
2926            drop(handle_1);
2927            model.other.take();
2928        });
2929
2930        assert_eq!(cx.cx.models.len(), 1);
2931        assert!(cx.subscriptions.is_empty());
2932        assert!(cx.model_observations.is_empty());
2933    }
2934
2935    #[crate::test(self)]
2936    fn test_subscribe_and_emit_from_model(cx: &mut MutableAppContext) {
2937        #[derive(Default)]
2938        struct Model {
2939            events: Vec<usize>,
2940        }
2941
2942        impl Entity for Model {
2943            type Event = usize;
2944        }
2945
2946        let handle_1 = cx.add_model(|_| Model::default());
2947        let handle_2 = cx.add_model(|_| Model::default());
2948        let handle_2b = handle_2.clone();
2949
2950        handle_1.update(cx, |_, c| {
2951            c.subscribe(&handle_2, move |model: &mut Model, event, c| {
2952                model.events.push(*event);
2953
2954                c.subscribe(&handle_2b, |model, event, _| {
2955                    model.events.push(*event * 2);
2956                });
2957            });
2958        });
2959
2960        handle_2.update(cx, |_, c| c.emit(7));
2961        assert_eq!(handle_1.read(cx).events, vec![7]);
2962
2963        handle_2.update(cx, |_, c| c.emit(5));
2964        assert_eq!(handle_1.read(cx).events, vec![7, 10, 5]);
2965    }
2966
2967    #[crate::test(self)]
2968    fn test_observe_and_notify_from_model(cx: &mut MutableAppContext) {
2969        #[derive(Default)]
2970        struct Model {
2971            count: usize,
2972            events: Vec<usize>,
2973        }
2974
2975        impl Entity for Model {
2976            type Event = ();
2977        }
2978
2979        let handle_1 = cx.add_model(|_| Model::default());
2980        let handle_2 = cx.add_model(|_| Model::default());
2981        let handle_2b = handle_2.clone();
2982
2983        handle_1.update(cx, |_, c| {
2984            c.observe(&handle_2, move |model, observed, c| {
2985                model.events.push(observed.read(c).count);
2986                c.observe(&handle_2b, |model, observed, c| {
2987                    model.events.push(observed.read(c).count * 2);
2988                });
2989            });
2990        });
2991
2992        handle_2.update(cx, |model, c| {
2993            model.count = 7;
2994            c.notify()
2995        });
2996        assert_eq!(handle_1.read(cx).events, vec![7]);
2997
2998        handle_2.update(cx, |model, c| {
2999            model.count = 5;
3000            c.notify()
3001        });
3002        assert_eq!(handle_1.read(cx).events, vec![7, 10, 5])
3003    }
3004
3005    #[crate::test(self)]
3006    fn test_view_handles(cx: &mut MutableAppContext) {
3007        struct View {
3008            other: Option<ViewHandle<View>>,
3009            events: Vec<String>,
3010        }
3011
3012        impl Entity for View {
3013            type Event = usize;
3014        }
3015
3016        impl super::View for View {
3017            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3018                Empty::new().boxed()
3019            }
3020
3021            fn ui_name() -> &'static str {
3022                "View"
3023            }
3024        }
3025
3026        impl View {
3027            fn new(other: Option<ViewHandle<View>>, cx: &mut ViewContext<Self>) -> Self {
3028                if let Some(other) = other.as_ref() {
3029                    cx.subscribe_to_view(other, |me, _, event, _| {
3030                        me.events.push(format!("observed event {}", event));
3031                    });
3032                }
3033                Self {
3034                    other,
3035                    events: Vec::new(),
3036                }
3037            }
3038        }
3039
3040        let (window_id, _) = cx.add_window(|cx| View::new(None, cx));
3041        let handle_1 = cx.add_view(window_id, |cx| View::new(None, cx));
3042        let handle_2 = cx.add_view(window_id, |cx| View::new(Some(handle_1.clone()), cx));
3043        assert_eq!(cx.cx.views.len(), 3);
3044
3045        handle_1.update(cx, |view, cx| {
3046            view.events.push("updated".into());
3047            cx.emit(1);
3048            cx.emit(2);
3049        });
3050        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
3051        assert_eq!(
3052            handle_2.read(cx).events,
3053            vec![
3054                "observed event 1".to_string(),
3055                "observed event 2".to_string(),
3056            ]
3057        );
3058
3059        handle_2.update(cx, |view, _| {
3060            drop(handle_1);
3061            view.other.take();
3062        });
3063
3064        assert_eq!(cx.cx.views.len(), 2);
3065        assert!(cx.subscriptions.is_empty());
3066        assert!(cx.model_observations.is_empty());
3067    }
3068
3069    #[crate::test(self)]
3070    fn test_add_window(cx: &mut MutableAppContext) {
3071        struct View {
3072            mouse_down_count: Arc<AtomicUsize>,
3073        }
3074
3075        impl Entity for View {
3076            type Event = ();
3077        }
3078
3079        impl super::View for View {
3080            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3081                let mouse_down_count = self.mouse_down_count.clone();
3082                EventHandler::new(Empty::new().boxed())
3083                    .on_mouse_down(move |_| {
3084                        mouse_down_count.fetch_add(1, SeqCst);
3085                        true
3086                    })
3087                    .boxed()
3088            }
3089
3090            fn ui_name() -> &'static str {
3091                "View"
3092            }
3093        }
3094
3095        let mouse_down_count = Arc::new(AtomicUsize::new(0));
3096        let (window_id, _) = cx.add_window(|_| View {
3097            mouse_down_count: mouse_down_count.clone(),
3098        });
3099        let presenter = cx.presenters_and_platform_windows[&window_id].0.clone();
3100        // Ensure window's root element is in a valid lifecycle state.
3101        presenter.borrow_mut().dispatch_event(
3102            Event::LeftMouseDown {
3103                position: Default::default(),
3104                cmd: false,
3105            },
3106            cx,
3107        );
3108        assert_eq!(mouse_down_count.load(SeqCst), 1);
3109    }
3110
3111    #[crate::test(self)]
3112    fn test_entity_release_hooks(cx: &mut MutableAppContext) {
3113        struct Model {
3114            released: Arc<Mutex<bool>>,
3115        }
3116
3117        struct View {
3118            released: Arc<Mutex<bool>>,
3119        }
3120
3121        impl Entity for Model {
3122            type Event = ();
3123
3124            fn release(&mut self, _: &mut MutableAppContext) {
3125                *self.released.lock() = true;
3126            }
3127        }
3128
3129        impl Entity for View {
3130            type Event = ();
3131
3132            fn release(&mut self, _: &mut MutableAppContext) {
3133                *self.released.lock() = true;
3134            }
3135        }
3136
3137        impl super::View for View {
3138            fn ui_name() -> &'static str {
3139                "View"
3140            }
3141
3142            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3143                Empty::new().boxed()
3144            }
3145        }
3146
3147        let model_released = Arc::new(Mutex::new(false));
3148        let view_released = Arc::new(Mutex::new(false));
3149
3150        let model = cx.add_model(|_| Model {
3151            released: model_released.clone(),
3152        });
3153
3154        let (window_id, _) = cx.add_window(|_| View {
3155            released: view_released.clone(),
3156        });
3157
3158        assert!(!*model_released.lock());
3159        assert!(!*view_released.lock());
3160
3161        cx.update(move || {
3162            drop(model);
3163        });
3164        assert!(*model_released.lock());
3165
3166        drop(cx.remove_window(window_id));
3167        assert!(*view_released.lock());
3168    }
3169
3170    #[crate::test(self)]
3171    fn test_subscribe_and_emit_from_view(cx: &mut MutableAppContext) {
3172        #[derive(Default)]
3173        struct View {
3174            events: Vec<usize>,
3175        }
3176
3177        impl Entity for View {
3178            type Event = usize;
3179        }
3180
3181        impl super::View for View {
3182            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3183                Empty::new().boxed()
3184            }
3185
3186            fn ui_name() -> &'static str {
3187                "View"
3188            }
3189        }
3190
3191        struct Model;
3192
3193        impl Entity for Model {
3194            type Event = usize;
3195        }
3196
3197        let (window_id, handle_1) = cx.add_window(|_| View::default());
3198        let handle_2 = cx.add_view(window_id, |_| View::default());
3199        let handle_2b = handle_2.clone();
3200        let handle_3 = cx.add_model(|_| Model);
3201
3202        handle_1.update(cx, |_, c| {
3203            c.subscribe_to_view(&handle_2, move |me, _, event, c| {
3204                me.events.push(*event);
3205
3206                c.subscribe_to_view(&handle_2b, |me, _, event, _| {
3207                    me.events.push(*event * 2);
3208                });
3209            });
3210
3211            c.subscribe_to_model(&handle_3, |me, _, event, _| {
3212                me.events.push(*event);
3213            })
3214        });
3215
3216        handle_2.update(cx, |_, c| c.emit(7));
3217        assert_eq!(handle_1.read(cx).events, vec![7]);
3218
3219        handle_2.update(cx, |_, c| c.emit(5));
3220        assert_eq!(handle_1.read(cx).events, vec![7, 10, 5]);
3221
3222        handle_3.update(cx, |_, c| c.emit(9));
3223        assert_eq!(handle_1.read(cx).events, vec![7, 10, 5, 9]);
3224    }
3225
3226    #[crate::test(self)]
3227    fn test_dropping_subscribers(cx: &mut MutableAppContext) {
3228        struct View;
3229
3230        impl Entity for View {
3231            type Event = ();
3232        }
3233
3234        impl super::View for View {
3235            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3236                Empty::new().boxed()
3237            }
3238
3239            fn ui_name() -> &'static str {
3240                "View"
3241            }
3242        }
3243
3244        struct Model;
3245
3246        impl Entity for Model {
3247            type Event = ();
3248        }
3249
3250        let (window_id, _) = cx.add_window(|_| View);
3251        let observing_view = cx.add_view(window_id, |_| View);
3252        let emitting_view = cx.add_view(window_id, |_| View);
3253        let observing_model = cx.add_model(|_| Model);
3254        let observed_model = cx.add_model(|_| Model);
3255
3256        observing_view.update(cx, |_, cx| {
3257            cx.subscribe_to_view(&emitting_view, |_, _, _, _| {});
3258            cx.subscribe_to_model(&observed_model, |_, _, _, _| {});
3259        });
3260        observing_model.update(cx, |_, cx| {
3261            cx.subscribe(&observed_model, |_, _, _| {});
3262        });
3263
3264        cx.update(|| {
3265            drop(observing_view);
3266            drop(observing_model);
3267        });
3268
3269        emitting_view.update(cx, |_, cx| cx.emit(()));
3270        observed_model.update(cx, |_, cx| cx.emit(()));
3271    }
3272
3273    #[crate::test(self)]
3274    fn test_observe_and_notify_from_view(cx: &mut MutableAppContext) {
3275        #[derive(Default)]
3276        struct View {
3277            events: Vec<usize>,
3278        }
3279
3280        impl Entity for View {
3281            type Event = usize;
3282        }
3283
3284        impl super::View for View {
3285            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3286                Empty::new().boxed()
3287            }
3288
3289            fn ui_name() -> &'static str {
3290                "View"
3291            }
3292        }
3293
3294        #[derive(Default)]
3295        struct Model {
3296            count: usize,
3297        }
3298
3299        impl Entity for Model {
3300            type Event = ();
3301        }
3302
3303        let (_, view) = cx.add_window(|_| View::default());
3304        let model = cx.add_model(|_| Model::default());
3305
3306        view.update(cx, |_, c| {
3307            c.observe_model(&model, |me, observed, c| {
3308                me.events.push(observed.read(c).count)
3309            });
3310        });
3311
3312        model.update(cx, |model, c| {
3313            model.count = 11;
3314            c.notify();
3315        });
3316        assert_eq!(view.read(cx).events, vec![11]);
3317    }
3318
3319    #[crate::test(self)]
3320    fn test_dropping_observers(cx: &mut MutableAppContext) {
3321        struct View;
3322
3323        impl Entity for View {
3324            type Event = ();
3325        }
3326
3327        impl super::View for View {
3328            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3329                Empty::new().boxed()
3330            }
3331
3332            fn ui_name() -> &'static str {
3333                "View"
3334            }
3335        }
3336
3337        struct Model;
3338
3339        impl Entity for Model {
3340            type Event = ();
3341        }
3342
3343        let (window_id, _) = cx.add_window(|_| View);
3344        let observing_view = cx.add_view(window_id, |_| View);
3345        let observing_model = cx.add_model(|_| Model);
3346        let observed_model = cx.add_model(|_| Model);
3347
3348        observing_view.update(cx, |_, cx| {
3349            cx.observe_model(&observed_model, |_, _, _| {});
3350        });
3351        observing_model.update(cx, |_, cx| {
3352            cx.observe(&observed_model, |_, _, _| {});
3353        });
3354
3355        cx.update(|| {
3356            drop(observing_view);
3357            drop(observing_model);
3358        });
3359
3360        observed_model.update(cx, |_, cx| cx.notify());
3361    }
3362
3363    #[crate::test(self)]
3364    fn test_focus(cx: &mut MutableAppContext) {
3365        struct View {
3366            name: String,
3367            events: Arc<Mutex<Vec<String>>>,
3368        }
3369
3370        impl Entity for View {
3371            type Event = ();
3372        }
3373
3374        impl super::View for View {
3375            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3376                Empty::new().boxed()
3377            }
3378
3379            fn ui_name() -> &'static str {
3380                "View"
3381            }
3382
3383            fn on_focus(&mut self, _: &mut ViewContext<Self>) {
3384                self.events.lock().push(format!("{} focused", &self.name));
3385            }
3386
3387            fn on_blur(&mut self, _: &mut ViewContext<Self>) {
3388                self.events.lock().push(format!("{} blurred", &self.name));
3389            }
3390        }
3391
3392        let events: Arc<Mutex<Vec<String>>> = Default::default();
3393        let (window_id, view_1) = cx.add_window(|_| View {
3394            events: events.clone(),
3395            name: "view 1".to_string(),
3396        });
3397        let view_2 = cx.add_view(window_id, |_| View {
3398            events: events.clone(),
3399            name: "view 2".to_string(),
3400        });
3401
3402        view_1.update(cx, |_, cx| cx.focus(&view_2));
3403        view_1.update(cx, |_, cx| cx.focus(&view_1));
3404        view_1.update(cx, |_, cx| cx.focus(&view_2));
3405        view_1.update(cx, |_, _| drop(view_2));
3406
3407        assert_eq!(
3408            *events.lock(),
3409            [
3410                "view 1 focused".to_string(),
3411                "view 1 blurred".to_string(),
3412                "view 2 focused".to_string(),
3413                "view 2 blurred".to_string(),
3414                "view 1 focused".to_string(),
3415                "view 1 blurred".to_string(),
3416                "view 2 focused".to_string(),
3417                "view 1 focused".to_string(),
3418            ],
3419        );
3420    }
3421
3422    #[crate::test(self)]
3423    fn test_dispatch_action(cx: &mut MutableAppContext) {
3424        struct ViewA {
3425            id: usize,
3426        }
3427
3428        impl Entity for ViewA {
3429            type Event = ();
3430        }
3431
3432        impl View for ViewA {
3433            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3434                Empty::new().boxed()
3435            }
3436
3437            fn ui_name() -> &'static str {
3438                "View"
3439            }
3440        }
3441
3442        struct ViewB {
3443            id: usize,
3444        }
3445
3446        impl Entity for ViewB {
3447            type Event = ();
3448        }
3449
3450        impl View for ViewB {
3451            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3452                Empty::new().boxed()
3453            }
3454
3455            fn ui_name() -> &'static str {
3456                "View"
3457            }
3458        }
3459
3460        struct ActionArg {
3461            foo: String,
3462        }
3463
3464        let actions = Rc::new(RefCell::new(Vec::new()));
3465
3466        let actions_clone = actions.clone();
3467        cx.add_global_action("action", move |_: &ActionArg, _: &mut MutableAppContext| {
3468            actions_clone.borrow_mut().push("global a".to_string());
3469        });
3470
3471        let actions_clone = actions.clone();
3472        cx.add_global_action("action", move |_: &ActionArg, _: &mut MutableAppContext| {
3473            actions_clone.borrow_mut().push("global b".to_string());
3474        });
3475
3476        let actions_clone = actions.clone();
3477        cx.add_action("action", move |view: &mut ViewA, arg: &ActionArg, cx| {
3478            assert_eq!(arg.foo, "bar");
3479            cx.propagate_action();
3480            actions_clone.borrow_mut().push(format!("{} a", view.id));
3481        });
3482
3483        let actions_clone = actions.clone();
3484        cx.add_action("action", move |view: &mut ViewA, _: &ActionArg, cx| {
3485            if view.id != 1 {
3486                cx.propagate_action();
3487            }
3488            actions_clone.borrow_mut().push(format!("{} b", view.id));
3489        });
3490
3491        let actions_clone = actions.clone();
3492        cx.add_action("action", move |view: &mut ViewB, _: &ActionArg, cx| {
3493            cx.propagate_action();
3494            actions_clone.borrow_mut().push(format!("{} c", view.id));
3495        });
3496
3497        let actions_clone = actions.clone();
3498        cx.add_action("action", move |view: &mut ViewB, _: &ActionArg, cx| {
3499            cx.propagate_action();
3500            actions_clone.borrow_mut().push(format!("{} d", view.id));
3501        });
3502
3503        let (window_id, view_1) = cx.add_window(|_| ViewA { id: 1 });
3504        let view_2 = cx.add_view(window_id, |_| ViewB { id: 2 });
3505        let view_3 = cx.add_view(window_id, |_| ViewA { id: 3 });
3506        let view_4 = cx.add_view(window_id, |_| ViewB { id: 4 });
3507
3508        cx.dispatch_action(
3509            window_id,
3510            vec![view_1.id(), view_2.id(), view_3.id(), view_4.id()],
3511            "action",
3512            ActionArg { foo: "bar".into() },
3513        );
3514
3515        assert_eq!(
3516            *actions.borrow(),
3517            vec!["4 d", "4 c", "3 b", "3 a", "2 d", "2 c", "1 b"]
3518        );
3519
3520        // Remove view_1, which doesn't propagate the action
3521        actions.borrow_mut().clear();
3522        cx.dispatch_action(
3523            window_id,
3524            vec![view_2.id(), view_3.id(), view_4.id()],
3525            "action",
3526            ActionArg { foo: "bar".into() },
3527        );
3528
3529        assert_eq!(
3530            *actions.borrow(),
3531            vec!["4 d", "4 c", "3 b", "3 a", "2 d", "2 c", "global b", "global a"]
3532        );
3533    }
3534
3535    #[crate::test(self)]
3536    fn test_dispatch_keystroke(cx: &mut MutableAppContext) {
3537        use std::cell::Cell;
3538
3539        #[derive(Clone)]
3540        struct ActionArg {
3541            key: String,
3542        }
3543
3544        struct View {
3545            id: usize,
3546            keymap_context: keymap::Context,
3547        }
3548
3549        impl Entity for View {
3550            type Event = ();
3551        }
3552
3553        impl super::View for View {
3554            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3555                Empty::new().boxed()
3556            }
3557
3558            fn ui_name() -> &'static str {
3559                "View"
3560            }
3561
3562            fn keymap_context(&self, _: &AppContext) -> keymap::Context {
3563                self.keymap_context.clone()
3564            }
3565        }
3566
3567        impl View {
3568            fn new(id: usize) -> Self {
3569                View {
3570                    id,
3571                    keymap_context: keymap::Context::default(),
3572                }
3573            }
3574        }
3575
3576        let mut view_1 = View::new(1);
3577        let mut view_2 = View::new(2);
3578        let mut view_3 = View::new(3);
3579        view_1.keymap_context.set.insert("a".into());
3580        view_2.keymap_context.set.insert("b".into());
3581        view_3.keymap_context.set.insert("c".into());
3582
3583        let (window_id, view_1) = cx.add_window(|_| view_1);
3584        let view_2 = cx.add_view(window_id, |_| view_2);
3585        let view_3 = cx.add_view(window_id, |_| view_3);
3586
3587        // This keymap's only binding dispatches an action on view 2 because that view will have
3588        // "a" and "b" in its context, but not "c".
3589        let binding = keymap::Binding::new("a", "action", Some("a && b && !c"))
3590            .with_arg(ActionArg { key: "a".into() });
3591        cx.add_bindings(vec![binding]);
3592
3593        let handled_action = Rc::new(Cell::new(false));
3594        let handled_action_clone = handled_action.clone();
3595        cx.add_action("action", move |view: &mut View, arg: &ActionArg, _| {
3596            handled_action_clone.set(true);
3597            assert_eq!(view.id, 2);
3598            assert_eq!(arg.key, "a");
3599        });
3600
3601        cx.dispatch_keystroke(
3602            window_id,
3603            vec![view_1.id(), view_2.id(), view_3.id()],
3604            &Keystroke::parse("a").unwrap(),
3605        )
3606        .unwrap();
3607
3608        assert!(handled_action.get());
3609    }
3610
3611    #[crate::test(self)]
3612    async fn test_model_condition(mut cx: TestAppContext) {
3613        struct Counter(usize);
3614
3615        impl super::Entity for Counter {
3616            type Event = ();
3617        }
3618
3619        impl Counter {
3620            fn inc(&mut self, cx: &mut ModelContext<Self>) {
3621                self.0 += 1;
3622                cx.notify();
3623            }
3624        }
3625
3626        let model = cx.add_model(|_| Counter(0));
3627
3628        let condition1 = model.condition(&cx, |model, _| model.0 == 2);
3629        let condition2 = model.condition(&cx, |model, _| model.0 == 3);
3630        smol::pin!(condition1, condition2);
3631
3632        model.update(&mut cx, |model, cx| model.inc(cx));
3633        assert_eq!(poll_once(&mut condition1).await, None);
3634        assert_eq!(poll_once(&mut condition2).await, None);
3635
3636        model.update(&mut cx, |model, cx| model.inc(cx));
3637        assert_eq!(poll_once(&mut condition1).await, Some(()));
3638        assert_eq!(poll_once(&mut condition2).await, None);
3639
3640        model.update(&mut cx, |model, cx| model.inc(cx));
3641        assert_eq!(poll_once(&mut condition2).await, Some(()));
3642
3643        model.update(&mut cx, |_, cx| cx.notify());
3644    }
3645
3646    #[crate::test(self)]
3647    #[should_panic]
3648    async fn test_model_condition_timeout(mut cx: TestAppContext) {
3649        struct Model;
3650
3651        impl super::Entity for Model {
3652            type Event = ();
3653        }
3654
3655        let model = cx.add_model(|_| Model);
3656        model.condition(&cx, |_, _| false).await;
3657    }
3658
3659    #[crate::test(self)]
3660    #[should_panic(expected = "model dropped with pending condition")]
3661    async fn test_model_condition_panic_on_drop(mut cx: TestAppContext) {
3662        struct Model;
3663
3664        impl super::Entity for Model {
3665            type Event = ();
3666        }
3667
3668        let model = cx.add_model(|_| Model);
3669        let condition = model.condition(&cx, |_, _| false);
3670        cx.update(|_| drop(model));
3671        condition.await;
3672    }
3673
3674    #[crate::test(self)]
3675    async fn test_view_condition(mut cx: TestAppContext) {
3676        struct Counter(usize);
3677
3678        impl super::Entity for Counter {
3679            type Event = ();
3680        }
3681
3682        impl super::View for Counter {
3683            fn ui_name() -> &'static str {
3684                "test view"
3685            }
3686
3687            fn render(&self, _: &AppContext) -> ElementBox {
3688                Empty::new().boxed()
3689            }
3690        }
3691
3692        impl Counter {
3693            fn inc(&mut self, cx: &mut ViewContext<Self>) {
3694                self.0 += 1;
3695                cx.notify();
3696            }
3697        }
3698
3699        let (_, view) = cx.add_window(|_| Counter(0));
3700
3701        let condition1 = view.condition(&cx, |view, _| view.0 == 2);
3702        let condition2 = view.condition(&cx, |view, _| view.0 == 3);
3703        smol::pin!(condition1, condition2);
3704
3705        view.update(&mut cx, |view, cx| view.inc(cx));
3706        assert_eq!(poll_once(&mut condition1).await, None);
3707        assert_eq!(poll_once(&mut condition2).await, None);
3708
3709        view.update(&mut cx, |view, cx| view.inc(cx));
3710        assert_eq!(poll_once(&mut condition1).await, Some(()));
3711        assert_eq!(poll_once(&mut condition2).await, None);
3712
3713        view.update(&mut cx, |view, cx| view.inc(cx));
3714        assert_eq!(poll_once(&mut condition2).await, Some(()));
3715        view.update(&mut cx, |_, cx| cx.notify());
3716    }
3717
3718    #[crate::test(self)]
3719    #[should_panic]
3720    async fn test_view_condition_timeout(mut cx: TestAppContext) {
3721        struct View;
3722
3723        impl super::Entity for View {
3724            type Event = ();
3725        }
3726
3727        impl super::View for View {
3728            fn ui_name() -> &'static str {
3729                "test view"
3730            }
3731
3732            fn render(&self, _: &AppContext) -> ElementBox {
3733                Empty::new().boxed()
3734            }
3735        }
3736
3737        let (_, view) = cx.add_window(|_| View);
3738        view.condition(&cx, |_, _| false).await;
3739    }
3740
3741    #[crate::test(self)]
3742    #[should_panic(expected = "view dropped with pending condition")]
3743    async fn test_view_condition_panic_on_drop(mut cx: TestAppContext) {
3744        struct View;
3745
3746        impl super::Entity for View {
3747            type Event = ();
3748        }
3749
3750        impl super::View for View {
3751            fn ui_name() -> &'static str {
3752                "test view"
3753            }
3754
3755            fn render(&self, _: &AppContext) -> ElementBox {
3756                Empty::new().boxed()
3757            }
3758        }
3759
3760        let window_id = cx.add_window(|_| View).0;
3761        let view = cx.add_view(window_id, |_| View);
3762
3763        let condition = view.condition(&cx, |_, _| false);
3764        cx.update(|_| drop(view));
3765        condition.await;
3766    }
3767}