app.rs

   1use crate::{
   2    elements::ElementBox,
   3    executor,
   4    keymap::{self, Keystroke},
   5    platform::{self, WindowOptions},
   6    presenter::Presenter,
   7    util::{post_inc, timeout},
   8    AssetCache, AssetSource, ClipboardItem, FontCache, PathPromptOptions, TextLayoutCache,
   9};
  10use anyhow::{anyhow, Result};
  11use keymap::MatchResult;
  12use parking_lot::{Mutex, RwLock};
  13use pathfinder_geometry::{rect::RectF, vector::vec2f};
  14use platform::Event;
  15use postage::{sink::Sink as _, stream::Stream as _};
  16use smol::prelude::*;
  17use std::{
  18    any::{type_name, Any, TypeId},
  19    cell::RefCell,
  20    collections::{hash_map::Entry, HashMap, HashSet, VecDeque},
  21    fmt::{self, Debug},
  22    hash::{Hash, Hasher},
  23    marker::PhantomData,
  24    path::PathBuf,
  25    rc::{self, Rc},
  26    sync::{Arc, Weak},
  27    time::Duration,
  28};
  29
  30pub trait Entity: 'static + Send + Sync {
  31    type Event;
  32}
  33
  34pub trait View: Entity {
  35    fn ui_name() -> &'static str;
  36    fn render<'a>(&self, app: &AppContext) -> ElementBox;
  37    fn on_focus(&mut self, _ctx: &mut ViewContext<Self>) {}
  38    fn on_blur(&mut self, _ctx: &mut ViewContext<Self>) {}
  39    fn keymap_context(&self, _: &AppContext) -> keymap::Context {
  40        Self::default_keymap_context()
  41    }
  42    fn default_keymap_context() -> keymap::Context {
  43        let mut ctx = keymap::Context::default();
  44        ctx.set.insert(Self::ui_name().into());
  45        ctx
  46    }
  47}
  48
  49pub trait ReadModel {
  50    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T;
  51}
  52
  53pub trait UpdateModel {
  54    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
  55    where
  56        T: Entity,
  57        F: FnOnce(&mut T, &mut ModelContext<T>) -> S;
  58}
  59
  60pub trait ReadView {
  61    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T;
  62}
  63
  64pub trait UpdateView {
  65    fn update_view<T, F, S>(&mut self, handle: &ViewHandle<T>, update: F) -> S
  66    where
  67        T: View,
  68        F: FnOnce(&mut T, &mut ViewContext<T>) -> S;
  69}
  70
  71pub struct Menu<'a> {
  72    pub name: &'a str,
  73    pub items: Vec<MenuItem<'a>>,
  74}
  75
  76pub enum MenuItem<'a> {
  77    Action {
  78        name: &'a str,
  79        keystroke: Option<&'a str>,
  80        action: &'a str,
  81        arg: Option<Box<dyn Any + 'static>>,
  82    },
  83    Separator,
  84}
  85
  86#[derive(Clone)]
  87pub struct App(Rc<RefCell<MutableAppContext>>);
  88
  89#[derive(Clone)]
  90pub struct TestAppContext(Rc<RefCell<MutableAppContext>>);
  91
  92impl App {
  93    pub fn test<T, A: AssetSource, F: FnOnce(&mut MutableAppContext) -> T>(
  94        asset_source: A,
  95        f: F,
  96    ) -> T {
  97        let platform = platform::test::platform();
  98        let foreground = Rc::new(executor::Foreground::test());
  99        let ctx = Rc::new(RefCell::new(MutableAppContext::new(
 100            foreground,
 101            Rc::new(platform),
 102            asset_source,
 103        )));
 104        ctx.borrow_mut().weak_self = Some(Rc::downgrade(&ctx));
 105        let mut ctx = ctx.borrow_mut();
 106        f(&mut *ctx)
 107    }
 108
 109    pub fn test_async<T, F, A: AssetSource, Fn>(asset_source: A, f: Fn) -> T
 110    where
 111        Fn: FnOnce(TestAppContext) -> F,
 112        F: Future<Output = T>,
 113    {
 114        let platform = platform::test::platform();
 115        let foreground = Rc::new(executor::Foreground::test());
 116        let ctx = TestAppContext(Rc::new(RefCell::new(MutableAppContext::new(
 117            foreground.clone(),
 118            Rc::new(platform),
 119            asset_source,
 120        ))));
 121        ctx.0.borrow_mut().weak_self = Some(Rc::downgrade(&ctx.0));
 122
 123        let future = f(ctx);
 124        smol::block_on(foreground.run(future))
 125    }
 126
 127    pub fn new(asset_source: impl AssetSource) -> Result<Self> {
 128        let platform = platform::current::platform();
 129        let foreground = Rc::new(executor::Foreground::platform(platform.dispatcher())?);
 130        let app = Self(Rc::new(RefCell::new(MutableAppContext::new(
 131            foreground,
 132            platform.clone(),
 133            asset_source,
 134        ))));
 135
 136        let ctx = app.0.clone();
 137        platform.on_menu_command(Box::new(move |command, arg| {
 138            let mut ctx = ctx.borrow_mut();
 139            if let Some(key_window_id) = ctx.platform.key_window_id() {
 140                if let Some((presenter, _)) =
 141                    ctx.presenters_and_platform_windows.get(&key_window_id)
 142                {
 143                    let presenter = presenter.clone();
 144                    let path = presenter.borrow().dispatch_path(ctx.as_ref());
 145                    ctx.dispatch_action_any(key_window_id, &path, command, arg.unwrap_or(&()));
 146                } else {
 147                    ctx.dispatch_global_action_any(command, arg.unwrap_or(&()));
 148                }
 149            } else {
 150                ctx.dispatch_global_action_any(command, arg.unwrap_or(&()));
 151            }
 152        }));
 153
 154        app.0.borrow_mut().weak_self = Some(Rc::downgrade(&app.0));
 155        Ok(app)
 156    }
 157
 158    pub fn on_become_active<F>(self, mut callback: F) -> Self
 159    where
 160        F: 'static + FnMut(&mut MutableAppContext),
 161    {
 162        let ctx = self.0.clone();
 163        self.0
 164            .borrow()
 165            .platform
 166            .on_become_active(Box::new(move || callback(&mut *ctx.borrow_mut())));
 167        self
 168    }
 169
 170    pub fn on_resign_active<F>(self, mut callback: F) -> Self
 171    where
 172        F: 'static + FnMut(&mut MutableAppContext),
 173    {
 174        let ctx = self.0.clone();
 175        self.0
 176            .borrow()
 177            .platform
 178            .on_resign_active(Box::new(move || callback(&mut *ctx.borrow_mut())));
 179        self
 180    }
 181
 182    pub fn on_event<F>(self, mut callback: F) -> Self
 183    where
 184        F: 'static + FnMut(Event, &mut MutableAppContext) -> bool,
 185    {
 186        let ctx = self.0.clone();
 187        self.0.borrow().platform.on_event(Box::new(move |event| {
 188            callback(event, &mut *ctx.borrow_mut())
 189        }));
 190        self
 191    }
 192
 193    pub fn on_open_files<F>(self, mut callback: F) -> Self
 194    where
 195        F: 'static + FnMut(Vec<PathBuf>, &mut MutableAppContext),
 196    {
 197        let ctx = self.0.clone();
 198        self.0
 199            .borrow()
 200            .platform
 201            .on_open_files(Box::new(move |paths| {
 202                callback(paths, &mut *ctx.borrow_mut())
 203            }));
 204        self
 205    }
 206
 207    pub fn run<F>(self, on_finish_launching: F)
 208    where
 209        F: 'static + FnOnce(&mut MutableAppContext),
 210    {
 211        let platform = self.0.borrow().platform.clone();
 212        platform.run(Box::new(move || {
 213            let mut ctx = self.0.borrow_mut();
 214            on_finish_launching(&mut *ctx);
 215        }))
 216    }
 217
 218    pub fn font_cache(&self) -> Arc<FontCache> {
 219        self.0.borrow().ctx.font_cache.clone()
 220    }
 221
 222    fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 223        let mut state = self.0.borrow_mut();
 224        state.pending_flushes += 1;
 225        let result = callback(&mut *state);
 226        state.flush_effects();
 227        result
 228    }
 229}
 230
 231impl TestAppContext {
 232    pub fn dispatch_action<T: 'static + Any>(
 233        &self,
 234        window_id: usize,
 235        responder_chain: Vec<usize>,
 236        name: &str,
 237        arg: T,
 238    ) {
 239        self.0.borrow_mut().dispatch_action_any(
 240            window_id,
 241            &responder_chain,
 242            name,
 243            Box::new(arg).as_ref(),
 244        );
 245    }
 246
 247    pub fn dispatch_keystroke(
 248        &self,
 249        window_id: usize,
 250        responder_chain: Vec<usize>,
 251        keystroke: &Keystroke,
 252    ) -> Result<bool> {
 253        let mut state = self.0.borrow_mut();
 254        state.dispatch_keystroke(window_id, responder_chain, keystroke)
 255    }
 256
 257    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 258    where
 259        T: Entity,
 260        F: FnOnce(&mut ModelContext<T>) -> T,
 261    {
 262        let mut state = self.0.borrow_mut();
 263        state.pending_flushes += 1;
 264        let handle = state.add_model(build_model);
 265        state.flush_effects();
 266        handle
 267    }
 268
 269    pub fn add_window<T, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<T>)
 270    where
 271        T: View,
 272        F: FnOnce(&mut ViewContext<T>) -> T,
 273    {
 274        self.0.borrow_mut().add_window(build_root_view)
 275    }
 276
 277    pub fn window_ids(&self) -> Vec<usize> {
 278        self.0.borrow().window_ids().collect()
 279    }
 280
 281    pub fn root_view<T: View>(&self, window_id: usize) -> Option<ViewHandle<T>> {
 282        self.0.borrow().root_view(window_id)
 283    }
 284
 285    pub fn add_view<T, F>(&mut self, window_id: usize, build_view: F) -> ViewHandle<T>
 286    where
 287        T: View,
 288        F: FnOnce(&mut ViewContext<T>) -> T,
 289    {
 290        let mut state = self.0.borrow_mut();
 291        state.pending_flushes += 1;
 292        let handle = state.add_view(window_id, build_view);
 293        state.flush_effects();
 294        handle
 295    }
 296
 297    pub fn add_option_view<T, F>(
 298        &mut self,
 299        window_id: usize,
 300        build_view: F,
 301    ) -> Option<ViewHandle<T>>
 302    where
 303        T: View,
 304        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
 305    {
 306        let mut state = self.0.borrow_mut();
 307        state.pending_flushes += 1;
 308        let handle = state.add_option_view(window_id, build_view);
 309        state.flush_effects();
 310        handle
 311    }
 312
 313    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 314        callback(self.0.borrow().as_ref())
 315    }
 316
 317    pub fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 318        let mut state = self.0.borrow_mut();
 319        // Don't increment pending flushes in order to effects to be flushed before the callback
 320        // completes, which is helpful in tests.
 321        let result = callback(&mut *state);
 322        // Flush effects after the callback just in case there are any. This can happen in edge
 323        // cases such as the closure dropping handles.
 324        state.flush_effects();
 325        result
 326    }
 327
 328    pub fn font_cache(&self) -> Arc<FontCache> {
 329        self.0.borrow().ctx.font_cache.clone()
 330    }
 331
 332    pub fn platform(&self) -> Rc<dyn platform::Platform> {
 333        self.0.borrow().platform.clone()
 334    }
 335}
 336
 337impl UpdateModel for TestAppContext {
 338    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
 339    where
 340        T: Entity,
 341        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
 342    {
 343        let mut state = self.0.borrow_mut();
 344        state.pending_flushes += 1;
 345        let result = state.update_model(handle, update);
 346        state.flush_effects();
 347        result
 348    }
 349}
 350
 351impl UpdateView for TestAppContext {
 352    fn update_view<T, F, S>(&mut self, handle: &ViewHandle<T>, update: F) -> S
 353    where
 354        T: View,
 355        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
 356    {
 357        let mut state = self.0.borrow_mut();
 358        state.pending_flushes += 1;
 359        let result = state.update_view(handle, update);
 360        state.flush_effects();
 361        result
 362    }
 363}
 364
 365type ActionCallback =
 366    dyn FnMut(&mut dyn AnyView, &dyn Any, &mut MutableAppContext, usize, usize) -> bool;
 367
 368type GlobalActionCallback = dyn FnMut(&dyn Any, &mut MutableAppContext);
 369
 370pub struct MutableAppContext {
 371    weak_self: Option<rc::Weak<RefCell<Self>>>,
 372    platform: Rc<dyn platform::Platform>,
 373    assets: Arc<AssetCache>,
 374    ctx: AppContext,
 375    actions: HashMap<TypeId, HashMap<String, Vec<Box<ActionCallback>>>>,
 376    global_actions: HashMap<String, Vec<Box<GlobalActionCallback>>>,
 377    keystroke_matcher: keymap::Matcher,
 378    next_entity_id: usize,
 379    next_window_id: usize,
 380    next_task_id: usize,
 381    subscriptions: HashMap<usize, Vec<Subscription>>,
 382    model_observations: HashMap<usize, Vec<ModelObservation>>,
 383    view_observations: HashMap<usize, Vec<ViewObservation>>,
 384    async_observations: HashMap<usize, postage::broadcast::Sender<()>>,
 385    presenters_and_platform_windows:
 386        HashMap<usize, (Rc<RefCell<Presenter>>, Box<dyn platform::Window>)>,
 387    debug_elements_callbacks: HashMap<usize, Box<dyn Fn(&AppContext) -> crate::json::Value>>,
 388    foreground: Rc<executor::Foreground>,
 389    future_handlers: Rc<RefCell<HashMap<usize, FutureHandler>>>,
 390    stream_handlers: Rc<RefCell<HashMap<usize, StreamHandler>>>,
 391    pending_effects: VecDeque<Effect>,
 392    pending_flushes: usize,
 393    flushing_effects: bool,
 394}
 395
 396impl MutableAppContext {
 397    pub fn new(
 398        foreground: Rc<executor::Foreground>,
 399        platform: Rc<dyn platform::Platform>,
 400        asset_source: impl AssetSource,
 401    ) -> Self {
 402        let fonts = platform.fonts();
 403        Self {
 404            weak_self: None,
 405            platform,
 406            assets: Arc::new(AssetCache::new(asset_source)),
 407            ctx: AppContext {
 408                models: Default::default(),
 409                views: Default::default(),
 410                windows: Default::default(),
 411                values: Default::default(),
 412                ref_counts: Arc::new(Mutex::new(RefCounts::default())),
 413                background: Arc::new(executor::Background::new()),
 414                thread_pool: scoped_pool::Pool::new(num_cpus::get(), "app"),
 415                font_cache: Arc::new(FontCache::new(fonts)),
 416            },
 417            actions: HashMap::new(),
 418            global_actions: HashMap::new(),
 419            keystroke_matcher: keymap::Matcher::default(),
 420            next_entity_id: 0,
 421            next_window_id: 0,
 422            next_task_id: 0,
 423            subscriptions: HashMap::new(),
 424            model_observations: HashMap::new(),
 425            view_observations: HashMap::new(),
 426            async_observations: HashMap::new(),
 427            presenters_and_platform_windows: HashMap::new(),
 428            debug_elements_callbacks: HashMap::new(),
 429            foreground,
 430            future_handlers: Default::default(),
 431            stream_handlers: Default::default(),
 432            pending_effects: VecDeque::new(),
 433            pending_flushes: 0,
 434            flushing_effects: false,
 435        }
 436    }
 437
 438    pub fn upgrade(&self) -> App {
 439        App(self.weak_self.as_ref().unwrap().upgrade().unwrap())
 440    }
 441
 442    pub fn platform(&self) -> Rc<dyn platform::Platform> {
 443        self.platform.clone()
 444    }
 445
 446    pub fn font_cache(&self) -> &Arc<FontCache> {
 447        &self.ctx.font_cache
 448    }
 449
 450    pub fn foreground_executor(&self) -> &Rc<executor::Foreground> {
 451        &self.foreground
 452    }
 453
 454    pub fn background_executor(&self) -> &Arc<executor::Background> {
 455        &self.ctx.background
 456    }
 457
 458    pub fn on_debug_elements<F>(&mut self, window_id: usize, callback: F)
 459    where
 460        F: 'static + Fn(&AppContext) -> crate::json::Value,
 461    {
 462        self.debug_elements_callbacks
 463            .insert(window_id, Box::new(callback));
 464    }
 465
 466    pub fn debug_elements(&self, window_id: usize) -> Option<crate::json::Value> {
 467        self.debug_elements_callbacks
 468            .get(&window_id)
 469            .map(|debug_elements| debug_elements(&self.ctx))
 470    }
 471
 472    pub fn add_action<S, V, T, F>(&mut self, name: S, mut handler: F)
 473    where
 474        S: Into<String>,
 475        V: View,
 476        T: Any,
 477        F: 'static + FnMut(&mut V, &T, &mut ViewContext<V>),
 478    {
 479        let name = name.into();
 480        let name_clone = name.clone();
 481        let handler = Box::new(
 482            move |view: &mut dyn AnyView,
 483                  arg: &dyn Any,
 484                  app: &mut MutableAppContext,
 485                  window_id: usize,
 486                  view_id: usize| {
 487                match arg.downcast_ref() {
 488                    Some(arg) => {
 489                        let mut ctx = ViewContext::new(app, window_id, view_id);
 490                        handler(
 491                            view.as_any_mut()
 492                                .downcast_mut()
 493                                .expect("downcast is type safe"),
 494                            arg,
 495                            &mut ctx,
 496                        );
 497                        ctx.halt_action_dispatch
 498                    }
 499                    None => {
 500                        log::error!("Could not downcast argument for action {}", name_clone);
 501                        false
 502                    }
 503                }
 504            },
 505        );
 506
 507        self.actions
 508            .entry(TypeId::of::<V>())
 509            .or_default()
 510            .entry(name)
 511            .or_default()
 512            .push(handler);
 513    }
 514
 515    pub fn add_global_action<S, T, F>(&mut self, name: S, mut handler: F)
 516    where
 517        S: Into<String>,
 518        T: 'static + Any,
 519        F: 'static + FnMut(&T, &mut MutableAppContext),
 520    {
 521        let name = name.into();
 522        let name_clone = name.clone();
 523        let handler = Box::new(move |arg: &dyn Any, app: &mut MutableAppContext| {
 524            if let Some(arg) = arg.downcast_ref() {
 525                handler(arg, app);
 526            } else {
 527                log::error!("Could not downcast argument for action {}", name_clone);
 528            }
 529        });
 530
 531        self.global_actions.entry(name).or_default().push(handler);
 532    }
 533
 534    pub fn window_ids(&self) -> impl Iterator<Item = usize> + '_ {
 535        self.ctx.windows.keys().cloned()
 536    }
 537
 538    pub fn root_view<T: View>(&self, window_id: usize) -> Option<ViewHandle<T>> {
 539        self.ctx
 540            .windows
 541            .get(&window_id)
 542            .and_then(|window| window.root_view.clone().downcast::<T>())
 543    }
 544
 545    pub fn root_view_id(&self, window_id: usize) -> Option<usize> {
 546        self.ctx.root_view_id(window_id)
 547    }
 548
 549    pub fn focused_view_id(&self, window_id: usize) -> Option<usize> {
 550        self.ctx.focused_view_id(window_id)
 551    }
 552
 553    pub fn render_view(&self, window_id: usize, view_id: usize) -> Result<ElementBox> {
 554        self.ctx.render_view(window_id, view_id)
 555    }
 556
 557    pub fn render_views(&self, window_id: usize) -> HashMap<usize, ElementBox> {
 558        self.ctx.render_views(window_id)
 559    }
 560
 561    pub fn update<T, F: FnOnce() -> T>(&mut self, callback: F) -> T {
 562        self.pending_flushes += 1;
 563        let result = callback();
 564        self.flush_effects();
 565        result
 566    }
 567
 568    pub fn set_menus(&self, menus: Vec<Menu>) {
 569        self.platform.set_menus(menus);
 570    }
 571
 572    pub fn prompt_for_paths<F>(&self, options: PathPromptOptions, done_fn: F)
 573    where
 574        F: 'static + FnOnce(Option<Vec<PathBuf>>, &mut MutableAppContext),
 575    {
 576        let app = self.weak_self.as_ref().unwrap().upgrade().unwrap();
 577        let foreground = self.foreground.clone();
 578        self.platform().prompt_for_paths(
 579            options,
 580            Box::new(move |paths| {
 581                foreground
 582                    .spawn(async move { (done_fn)(paths, &mut *app.borrow_mut()) })
 583                    .detach();
 584            }),
 585        );
 586    }
 587
 588    pub(crate) fn notify_view(&mut self, window_id: usize, view_id: usize) {
 589        self.pending_effects
 590            .push_back(Effect::ViewNotification { window_id, view_id });
 591    }
 592
 593    pub fn dispatch_action<T: 'static + Any>(
 594        &mut self,
 595        window_id: usize,
 596        responder_chain: Vec<usize>,
 597        name: &str,
 598        arg: T,
 599    ) {
 600        self.dispatch_action_any(window_id, &responder_chain, name, Box::new(arg).as_ref());
 601    }
 602
 603    pub(crate) fn dispatch_action_any(
 604        &mut self,
 605        window_id: usize,
 606        path: &[usize],
 607        name: &str,
 608        arg: &dyn Any,
 609    ) -> bool {
 610        self.pending_flushes += 1;
 611        let mut halted_dispatch = false;
 612
 613        for view_id in path.iter().rev() {
 614            if let Some(mut view) = self.ctx.views.remove(&(window_id, *view_id)) {
 615                let type_id = view.as_any().type_id();
 616
 617                if let Some((name, mut handlers)) = self
 618                    .actions
 619                    .get_mut(&type_id)
 620                    .and_then(|h| h.remove_entry(name))
 621                {
 622                    for handler in handlers.iter_mut().rev() {
 623                        let halt_dispatch = handler(view.as_mut(), arg, self, window_id, *view_id);
 624                        if halt_dispatch {
 625                            halted_dispatch = true;
 626                            break;
 627                        }
 628                    }
 629                    self.actions
 630                        .get_mut(&type_id)
 631                        .unwrap()
 632                        .insert(name, handlers);
 633                }
 634
 635                self.ctx.views.insert((window_id, *view_id), view);
 636
 637                if halted_dispatch {
 638                    break;
 639                }
 640            }
 641        }
 642
 643        if !halted_dispatch {
 644            self.dispatch_global_action_any(name, arg);
 645        }
 646
 647        self.flush_effects();
 648        halted_dispatch
 649    }
 650
 651    pub fn dispatch_global_action<T: 'static + Any>(&mut self, name: &str, arg: T) {
 652        self.dispatch_global_action_any(name, Box::new(arg).as_ref());
 653    }
 654
 655    fn dispatch_global_action_any(&mut self, name: &str, arg: &dyn Any) {
 656        if let Some((name, mut handlers)) = self.global_actions.remove_entry(name) {
 657            self.pending_flushes += 1;
 658            for handler in handlers.iter_mut().rev() {
 659                handler(arg, self);
 660            }
 661            self.global_actions.insert(name, handlers);
 662            self.flush_effects();
 663        }
 664    }
 665
 666    pub fn add_bindings<T: IntoIterator<Item = keymap::Binding>>(&mut self, bindings: T) {
 667        self.keystroke_matcher.add_bindings(bindings);
 668    }
 669
 670    pub fn dispatch_keystroke(
 671        &mut self,
 672        window_id: usize,
 673        responder_chain: Vec<usize>,
 674        keystroke: &Keystroke,
 675    ) -> Result<bool> {
 676        let mut context_chain = Vec::new();
 677        let mut context = keymap::Context::default();
 678        for view_id in &responder_chain {
 679            if let Some(view) = self.ctx.views.get(&(window_id, *view_id)) {
 680                context.extend(view.keymap_context(self.as_ref()));
 681                context_chain.push(context.clone());
 682            } else {
 683                return Err(anyhow!(
 684                    "View {} in responder chain does not exist",
 685                    view_id
 686                ));
 687            }
 688        }
 689
 690        let mut pending = false;
 691        for (i, ctx) in context_chain.iter().enumerate().rev() {
 692            match self
 693                .keystroke_matcher
 694                .push_keystroke(keystroke.clone(), responder_chain[i], ctx)
 695            {
 696                MatchResult::None => {}
 697                MatchResult::Pending => pending = true,
 698                MatchResult::Action { name, arg } => {
 699                    if self.dispatch_action_any(
 700                        window_id,
 701                        &responder_chain[0..=i],
 702                        &name,
 703                        arg.as_ref().map(|arg| arg.as_ref()).unwrap_or(&()),
 704                    ) {
 705                        return Ok(true);
 706                    }
 707                }
 708            }
 709        }
 710
 711        Ok(pending)
 712    }
 713
 714    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 715    where
 716        T: Entity,
 717        F: FnOnce(&mut ModelContext<T>) -> T,
 718    {
 719        self.pending_flushes += 1;
 720        let model_id = post_inc(&mut self.next_entity_id);
 721        let handle = ModelHandle::new(model_id, &self.ctx.ref_counts);
 722        let mut ctx = ModelContext::new(self, model_id);
 723        let model = build_model(&mut ctx);
 724        self.ctx.models.insert(model_id, Box::new(model));
 725        self.flush_effects();
 726        handle
 727    }
 728
 729    pub fn add_window<T, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<T>)
 730    where
 731        T: View,
 732        F: FnOnce(&mut ViewContext<T>) -> T,
 733    {
 734        self.pending_flushes += 1;
 735        let window_id = post_inc(&mut self.next_window_id);
 736        let root_view = self.add_view(window_id, build_root_view);
 737        self.ctx.windows.insert(
 738            window_id,
 739            Window {
 740                root_view: root_view.clone().into(),
 741                focused_view_id: root_view.id(),
 742                invalidation: None,
 743            },
 744        );
 745        self.open_platform_window(window_id);
 746        self.flush_effects();
 747
 748        (window_id, root_view)
 749    }
 750
 751    pub fn remove_window(&mut self, window_id: usize) {
 752        self.ctx.windows.remove(&window_id);
 753        self.presenters_and_platform_windows.remove(&window_id);
 754        self.remove_dropped_entities();
 755    }
 756
 757    fn open_platform_window(&mut self, window_id: usize) {
 758        let mut window = self.platform.open_window(
 759            window_id,
 760            WindowOptions {
 761                bounds: RectF::new(vec2f(0., 0.), vec2f(1024., 768.)),
 762                title: "Zed".into(),
 763            },
 764            self.foreground.clone(),
 765        );
 766        let text_layout_cache = TextLayoutCache::new(self.platform.fonts());
 767        let presenter = Rc::new(RefCell::new(Presenter::new(
 768            window_id,
 769            self.ctx.font_cache.clone(),
 770            text_layout_cache,
 771            self.assets.clone(),
 772            self,
 773        )));
 774
 775        {
 776            let mut app = self.upgrade();
 777            let presenter = presenter.clone();
 778            window.on_event(Box::new(move |event| {
 779                app.update(|ctx| {
 780                    if let Event::KeyDown { keystroke, .. } = &event {
 781                        if ctx
 782                            .dispatch_keystroke(
 783                                window_id,
 784                                presenter.borrow().dispatch_path(ctx.as_ref()),
 785                                keystroke,
 786                            )
 787                            .unwrap()
 788                        {
 789                            return;
 790                        }
 791                    }
 792
 793                    presenter.borrow_mut().dispatch_event(event, ctx);
 794                })
 795            }));
 796        }
 797
 798        {
 799            let mut app = self.upgrade();
 800            let presenter = presenter.clone();
 801            window.on_resize(Box::new(move |window| {
 802                app.update(|ctx| {
 803                    let scene = presenter.borrow_mut().build_scene(
 804                        window.size(),
 805                        window.scale_factor(),
 806                        ctx,
 807                    );
 808                    window.present_scene(scene);
 809                })
 810            }));
 811        }
 812
 813        {
 814            let mut app = self.upgrade();
 815            window.on_close(Box::new(move || {
 816                app.update(|ctx| ctx.remove_window(window_id));
 817            }));
 818        }
 819
 820        self.presenters_and_platform_windows
 821            .insert(window_id, (presenter.clone(), window));
 822
 823        self.on_debug_elements(window_id, move |ctx| {
 824            presenter.borrow().debug_elements(ctx).unwrap()
 825        });
 826    }
 827
 828    pub fn add_view<T, F>(&mut self, window_id: usize, build_view: F) -> ViewHandle<T>
 829    where
 830        T: View,
 831        F: FnOnce(&mut ViewContext<T>) -> T,
 832    {
 833        self.add_option_view(window_id, |ctx| Some(build_view(ctx)))
 834            .unwrap()
 835    }
 836
 837    pub fn add_option_view<T, F>(
 838        &mut self,
 839        window_id: usize,
 840        build_view: F,
 841    ) -> Option<ViewHandle<T>>
 842    where
 843        T: View,
 844        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
 845    {
 846        let view_id = post_inc(&mut self.next_entity_id);
 847        self.pending_flushes += 1;
 848        let handle = ViewHandle::new(window_id, view_id, &self.ctx.ref_counts);
 849        let mut ctx = ViewContext::new(self, window_id, view_id);
 850        let handle = if let Some(view) = build_view(&mut ctx) {
 851            self.ctx.views.insert((window_id, view_id), Box::new(view));
 852            if let Some(window) = self.ctx.windows.get_mut(&window_id) {
 853                window
 854                    .invalidation
 855                    .get_or_insert_with(Default::default)
 856                    .updated
 857                    .insert(view_id);
 858            }
 859            Some(handle)
 860        } else {
 861            None
 862        };
 863        self.flush_effects();
 864        handle
 865    }
 866
 867    fn remove_dropped_entities(&mut self) {
 868        loop {
 869            let (dropped_models, dropped_views, dropped_values) =
 870                self.ctx.ref_counts.lock().take_dropped();
 871            if dropped_models.is_empty() && dropped_views.is_empty() && dropped_values.is_empty() {
 872                break;
 873            }
 874
 875            for model_id in dropped_models {
 876                self.ctx.models.remove(&model_id);
 877                self.subscriptions.remove(&model_id);
 878                self.model_observations.remove(&model_id);
 879                self.async_observations.remove(&model_id);
 880            }
 881
 882            for (window_id, view_id) in dropped_views {
 883                self.subscriptions.remove(&view_id);
 884                self.model_observations.remove(&view_id);
 885                self.async_observations.remove(&view_id);
 886                self.ctx.views.remove(&(window_id, view_id));
 887                if let Some(window) = self.ctx.windows.get_mut(&window_id) {
 888                    window
 889                        .invalidation
 890                        .get_or_insert_with(Default::default)
 891                        .removed
 892                        .push(view_id);
 893                }
 894            }
 895
 896            let mut values = self.ctx.values.write();
 897            for key in dropped_values {
 898                values.remove(&key);
 899            }
 900        }
 901    }
 902
 903    fn flush_effects(&mut self) {
 904        self.pending_flushes = self.pending_flushes.saturating_sub(1);
 905
 906        if !self.flushing_effects && self.pending_flushes == 0 {
 907            self.flushing_effects = true;
 908
 909            loop {
 910                if let Some(effect) = self.pending_effects.pop_front() {
 911                    match effect {
 912                        Effect::Event { entity_id, payload } => self.emit_event(entity_id, payload),
 913                        Effect::ModelNotification { model_id } => {
 914                            self.notify_model_observers(model_id)
 915                        }
 916                        Effect::ViewNotification { window_id, view_id } => {
 917                            self.notify_view_observers(window_id, view_id)
 918                        }
 919                        Effect::Focus { window_id, view_id } => {
 920                            self.focus(window_id, view_id);
 921                        }
 922                    }
 923                } else {
 924                    self.remove_dropped_entities();
 925                    self.update_windows();
 926
 927                    if self.pending_effects.is_empty() {
 928                        self.flushing_effects = false;
 929
 930                        for (key, view) in &self.ctx.views {
 931                            log::info!("{:?} {}", key, view.ui_name());
 932                        }
 933
 934                        break;
 935                    }
 936                }
 937            }
 938        }
 939    }
 940
 941    fn update_windows(&mut self) {
 942        let mut invalidations = HashMap::new();
 943        for (window_id, window) in &mut self.ctx.windows {
 944            if let Some(invalidation) = window.invalidation.take() {
 945                invalidations.insert(*window_id, invalidation);
 946            }
 947        }
 948
 949        for (window_id, invalidation) in invalidations {
 950            if let Some((presenter, mut window)) =
 951                self.presenters_and_platform_windows.remove(&window_id)
 952            {
 953                {
 954                    let mut presenter = presenter.borrow_mut();
 955                    presenter.invalidate(invalidation, self.as_ref());
 956                    let scene = presenter.build_scene(window.size(), window.scale_factor(), self);
 957                    window.present_scene(scene);
 958                }
 959                self.presenters_and_platform_windows
 960                    .insert(window_id, (presenter, window));
 961            }
 962        }
 963    }
 964
 965    fn emit_event(&mut self, entity_id: usize, payload: Box<dyn Any>) {
 966        if let Some(subscriptions) = self.subscriptions.remove(&entity_id) {
 967            for mut subscription in subscriptions {
 968                let alive = match &mut subscription {
 969                    Subscription::FromModel { model_id, callback } => {
 970                        if let Some(mut model) = self.ctx.models.remove(model_id) {
 971                            callback(model.as_any_mut(), payload.as_ref(), self, *model_id);
 972                            self.ctx.models.insert(*model_id, model);
 973                            true
 974                        } else {
 975                            false
 976                        }
 977                    }
 978                    Subscription::FromView {
 979                        window_id,
 980                        view_id,
 981                        callback,
 982                    } => {
 983                        if let Some(mut view) = self.ctx.views.remove(&(*window_id, *view_id)) {
 984                            callback(
 985                                view.as_any_mut(),
 986                                payload.as_ref(),
 987                                self,
 988                                *window_id,
 989                                *view_id,
 990                            );
 991                            self.ctx.views.insert((*window_id, *view_id), view);
 992                            true
 993                        } else {
 994                            false
 995                        }
 996                    }
 997                };
 998
 999                if alive {
1000                    self.subscriptions
1001                        .entry(entity_id)
1002                        .or_default()
1003                        .push(subscription);
1004                }
1005            }
1006        }
1007    }
1008
1009    fn notify_model_observers(&mut self, observed_id: usize) {
1010        if let Some(observations) = self.model_observations.remove(&observed_id) {
1011            if self.ctx.models.contains_key(&observed_id) {
1012                for mut observation in observations {
1013                    let alive = match &mut observation {
1014                        ModelObservation::FromModel { model_id, callback } => {
1015                            if let Some(mut model) = self.ctx.models.remove(model_id) {
1016                                callback(model.as_any_mut(), observed_id, self, *model_id);
1017                                self.ctx.models.insert(*model_id, model);
1018                                true
1019                            } else {
1020                                false
1021                            }
1022                        }
1023                        ModelObservation::FromView {
1024                            window_id,
1025                            view_id,
1026                            callback,
1027                        } => {
1028                            if let Some(mut view) = self.ctx.views.remove(&(*window_id, *view_id)) {
1029                                callback(
1030                                    view.as_any_mut(),
1031                                    observed_id,
1032                                    self,
1033                                    *window_id,
1034                                    *view_id,
1035                                );
1036                                self.ctx.views.insert((*window_id, *view_id), view);
1037                                true
1038                            } else {
1039                                false
1040                            }
1041                        }
1042                    };
1043
1044                    if alive {
1045                        self.model_observations
1046                            .entry(observed_id)
1047                            .or_default()
1048                            .push(observation);
1049                    }
1050                }
1051            }
1052        }
1053
1054        if let Entry::Occupied(mut entry) = self.async_observations.entry(observed_id) {
1055            if entry.get_mut().blocking_send(()).is_err() {
1056                entry.remove_entry();
1057            }
1058        }
1059    }
1060
1061    fn notify_view_observers(&mut self, window_id: usize, view_id: usize) {
1062        if let Some(window) = self.ctx.windows.get_mut(&window_id) {
1063            window
1064                .invalidation
1065                .get_or_insert_with(Default::default)
1066                .updated
1067                .insert(view_id);
1068        }
1069
1070        if let Some(observations) = self.view_observations.remove(&view_id) {
1071            if self.ctx.models.contains_key(&view_id) {
1072                for mut observation in observations {
1073                    let alive = if let Some(mut view) = self
1074                        .ctx
1075                        .views
1076                        .remove(&(observation.window_id, observation.view_id))
1077                    {
1078                        (observation.callback)(
1079                            view.as_any_mut(),
1080                            view_id,
1081                            window_id,
1082                            self,
1083                            observation.window_id,
1084                            observation.view_id,
1085                        );
1086                        self.ctx
1087                            .views
1088                            .insert((observation.window_id, observation.view_id), view);
1089                        true
1090                    } else {
1091                        false
1092                    };
1093
1094                    if alive {
1095                        self.view_observations
1096                            .entry(view_id)
1097                            .or_default()
1098                            .push(observation);
1099                    }
1100                }
1101            }
1102        }
1103
1104        if let Entry::Occupied(mut entry) = self.async_observations.entry(view_id) {
1105            if entry.get_mut().blocking_send(()).is_err() {
1106                entry.remove_entry();
1107            }
1108        }
1109    }
1110
1111    fn focus(&mut self, window_id: usize, focused_id: usize) {
1112        if self
1113            .ctx
1114            .windows
1115            .get(&window_id)
1116            .map(|w| w.focused_view_id)
1117            .map_or(false, |cur_focused| cur_focused == focused_id)
1118        {
1119            return;
1120        }
1121
1122        self.pending_flushes += 1;
1123
1124        let blurred_id = self.ctx.windows.get_mut(&window_id).map(|window| {
1125            let blurred_id = window.focused_view_id;
1126            window.focused_view_id = focused_id;
1127            blurred_id
1128        });
1129
1130        if let Some(blurred_id) = blurred_id {
1131            if let Some(mut blurred_view) = self.ctx.views.remove(&(window_id, blurred_id)) {
1132                blurred_view.on_blur(self, window_id, blurred_id);
1133                self.ctx.views.insert((window_id, blurred_id), blurred_view);
1134            }
1135        }
1136
1137        if let Some(mut focused_view) = self.ctx.views.remove(&(window_id, focused_id)) {
1138            focused_view.on_focus(self, window_id, focused_id);
1139            self.ctx.views.insert((window_id, focused_id), focused_view);
1140        }
1141
1142        self.flush_effects();
1143    }
1144
1145    fn spawn<F, T>(&mut self, spawner: Spawner, future: F) -> EntityTask<T>
1146    where
1147        F: 'static + Future,
1148        T: 'static,
1149    {
1150        let task_id = post_inc(&mut self.next_task_id);
1151        let app = self.weak_self.as_ref().unwrap().upgrade().unwrap();
1152        let task = {
1153            let app = app.clone();
1154            self.foreground.spawn(async move {
1155                let output = future.await;
1156                app.borrow_mut()
1157                    .handle_future_output(task_id, Box::new(output))
1158                    .map(|output| *output.downcast::<T>().unwrap())
1159            })
1160        };
1161        EntityTask::new(
1162            task_id,
1163            task,
1164            spawner,
1165            TaskHandlerMap::Future(self.future_handlers.clone()),
1166        )
1167    }
1168
1169    fn spawn_stream<F, T>(&mut self, spawner: Spawner, mut stream: F) -> EntityTask<T>
1170    where
1171        F: 'static + Stream + Unpin,
1172        T: 'static,
1173    {
1174        let task_id = post_inc(&mut self.next_task_id);
1175        let app = self.weak_self.as_ref().unwrap().upgrade().unwrap();
1176        let task = self.foreground.spawn(async move {
1177            loop {
1178                match stream.next().await {
1179                    Some(item) => {
1180                        let mut app = app.borrow_mut();
1181                        if app.handle_stream_item(task_id, Box::new(item)) {
1182                            break;
1183                        }
1184                    }
1185                    None => {
1186                        break;
1187                    }
1188                }
1189            }
1190
1191            app.borrow_mut()
1192                .stream_completed(task_id)
1193                .map(|output| *output.downcast::<T>().unwrap())
1194        });
1195
1196        EntityTask::new(
1197            task_id,
1198            task,
1199            spawner,
1200            TaskHandlerMap::Stream(self.stream_handlers.clone()),
1201        )
1202    }
1203
1204    fn handle_future_output(
1205        &mut self,
1206        task_id: usize,
1207        output: Box<dyn Any>,
1208    ) -> Option<Box<dyn Any>> {
1209        self.pending_flushes += 1;
1210        let future_callback = self.future_handlers.borrow_mut().remove(&task_id).unwrap();
1211        let result = future_callback(output, self);
1212        self.flush_effects();
1213        result
1214    }
1215
1216    fn handle_stream_item(&mut self, task_id: usize, output: Box<dyn Any>) -> bool {
1217        self.pending_flushes += 1;
1218
1219        let mut handler = self.stream_handlers.borrow_mut().remove(&task_id).unwrap();
1220        let halt = (handler.item_callback)(output, self);
1221        self.stream_handlers.borrow_mut().insert(task_id, handler);
1222
1223        self.flush_effects();
1224        halt
1225    }
1226
1227    fn stream_completed(&mut self, task_id: usize) -> Option<Box<dyn Any>> {
1228        self.pending_flushes += 1;
1229
1230        let handler = self.stream_handlers.borrow_mut().remove(&task_id).unwrap();
1231        let result = (handler.done_callback)(self);
1232
1233        self.flush_effects();
1234        result
1235    }
1236
1237    pub fn write_to_clipboard(&self, item: ClipboardItem) {
1238        self.platform.write_to_clipboard(item);
1239    }
1240
1241    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
1242        self.platform.read_from_clipboard()
1243    }
1244}
1245
1246impl ReadModel for MutableAppContext {
1247    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
1248        if let Some(model) = self.ctx.models.get(&handle.model_id) {
1249            model
1250                .as_any()
1251                .downcast_ref()
1252                .expect("downcast is type safe")
1253        } else {
1254            panic!("circular model reference");
1255        }
1256    }
1257}
1258
1259impl UpdateModel for MutableAppContext {
1260    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
1261    where
1262        T: Entity,
1263        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
1264    {
1265        if let Some(mut model) = self.ctx.models.remove(&handle.model_id) {
1266            self.pending_flushes += 1;
1267            let mut ctx = ModelContext::new(self, handle.model_id);
1268            let result = update(
1269                model
1270                    .as_any_mut()
1271                    .downcast_mut()
1272                    .expect("downcast is type safe"),
1273                &mut ctx,
1274            );
1275            self.ctx.models.insert(handle.model_id, model);
1276            self.flush_effects();
1277            result
1278        } else {
1279            panic!("circular model update");
1280        }
1281    }
1282}
1283
1284impl ReadView for MutableAppContext {
1285    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
1286        if let Some(view) = self.ctx.views.get(&(handle.window_id, handle.view_id)) {
1287            view.as_any().downcast_ref().expect("downcast is type safe")
1288        } else {
1289            panic!("circular view reference");
1290        }
1291    }
1292}
1293
1294impl UpdateView for MutableAppContext {
1295    fn update_view<T, F, S>(&mut self, handle: &ViewHandle<T>, update: F) -> S
1296    where
1297        T: View,
1298        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
1299    {
1300        self.pending_flushes += 1;
1301        let mut view = self
1302            .ctx
1303            .views
1304            .remove(&(handle.window_id, handle.view_id))
1305            .expect("circular view update");
1306
1307        let mut ctx = ViewContext::new(self, handle.window_id, handle.view_id);
1308        let result = update(
1309            view.as_any_mut()
1310                .downcast_mut()
1311                .expect("downcast is type safe"),
1312            &mut ctx,
1313        );
1314        self.ctx
1315            .views
1316            .insert((handle.window_id, handle.view_id), view);
1317        self.flush_effects();
1318        result
1319    }
1320}
1321
1322impl AsRef<AppContext> for MutableAppContext {
1323    fn as_ref(&self) -> &AppContext {
1324        &self.ctx
1325    }
1326}
1327
1328pub struct AppContext {
1329    models: HashMap<usize, Box<dyn AnyModel>>,
1330    views: HashMap<(usize, usize), Box<dyn AnyView>>,
1331    windows: HashMap<usize, Window>,
1332    values: RwLock<HashMap<(TypeId, usize), Box<dyn Any>>>,
1333    background: Arc<executor::Background>,
1334    ref_counts: Arc<Mutex<RefCounts>>,
1335    thread_pool: scoped_pool::Pool,
1336    font_cache: Arc<FontCache>,
1337}
1338
1339impl AppContext {
1340    pub fn root_view_id(&self, window_id: usize) -> Option<usize> {
1341        self.windows
1342            .get(&window_id)
1343            .map(|window| window.root_view.id())
1344    }
1345
1346    pub fn focused_view_id(&self, window_id: usize) -> Option<usize> {
1347        self.windows
1348            .get(&window_id)
1349            .map(|window| window.focused_view_id)
1350    }
1351
1352    pub fn render_view(&self, window_id: usize, view_id: usize) -> Result<ElementBox> {
1353        self.views
1354            .get(&(window_id, view_id))
1355            .map(|v| v.render(self))
1356            .ok_or(anyhow!("view not found"))
1357    }
1358
1359    pub fn render_views(&self, window_id: usize) -> HashMap<usize, ElementBox> {
1360        self.views
1361            .iter()
1362            .filter_map(|((win_id, view_id), view)| {
1363                if *win_id == window_id {
1364                    Some((*view_id, view.render(self)))
1365                } else {
1366                    None
1367                }
1368            })
1369            .collect::<HashMap<_, ElementBox>>()
1370    }
1371
1372    pub fn background_executor(&self) -> &Arc<executor::Background> {
1373        &self.background
1374    }
1375
1376    pub fn font_cache(&self) -> &FontCache {
1377        &self.font_cache
1378    }
1379
1380    pub fn thread_pool(&self) -> &scoped_pool::Pool {
1381        &self.thread_pool
1382    }
1383
1384    pub fn value<Tag: 'static, T: 'static + Default>(&self, id: usize) -> ValueHandle<T> {
1385        let key = (TypeId::of::<Tag>(), id);
1386        let mut values = self.values.write();
1387        values.entry(key).or_insert_with(|| Box::new(T::default()));
1388        ValueHandle::new(TypeId::of::<Tag>(), id, &self.ref_counts)
1389    }
1390}
1391
1392impl ReadModel for AppContext {
1393    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
1394        if let Some(model) = self.models.get(&handle.model_id) {
1395            model
1396                .as_any()
1397                .downcast_ref()
1398                .expect("downcast should be type safe")
1399        } else {
1400            panic!("circular model reference");
1401        }
1402    }
1403}
1404
1405impl ReadView for AppContext {
1406    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
1407        if let Some(view) = self.views.get(&(handle.window_id, handle.view_id)) {
1408            view.as_any()
1409                .downcast_ref()
1410                .expect("downcast should be type safe")
1411        } else {
1412            panic!("circular view reference");
1413        }
1414    }
1415}
1416
1417struct Window {
1418    root_view: AnyViewHandle,
1419    focused_view_id: usize,
1420    invalidation: Option<WindowInvalidation>,
1421}
1422
1423#[derive(Default, Clone)]
1424pub struct WindowInvalidation {
1425    pub updated: HashSet<usize>,
1426    pub removed: Vec<usize>,
1427}
1428
1429pub enum Effect {
1430    Event {
1431        entity_id: usize,
1432        payload: Box<dyn Any>,
1433    },
1434    ModelNotification {
1435        model_id: usize,
1436    },
1437    ViewNotification {
1438        window_id: usize,
1439        view_id: usize,
1440    },
1441    Focus {
1442        window_id: usize,
1443        view_id: usize,
1444    },
1445}
1446
1447pub trait AnyModel: Send + Sync {
1448    fn as_any(&self) -> &dyn Any;
1449    fn as_any_mut(&mut self) -> &mut dyn Any;
1450}
1451
1452impl<T> AnyModel for T
1453where
1454    T: Entity,
1455{
1456    fn as_any(&self) -> &dyn Any {
1457        self
1458    }
1459
1460    fn as_any_mut(&mut self) -> &mut dyn Any {
1461        self
1462    }
1463}
1464
1465pub trait AnyView: Send + Sync {
1466    fn as_any(&self) -> &dyn Any;
1467    fn as_any_mut(&mut self) -> &mut dyn Any;
1468    fn ui_name(&self) -> &'static str;
1469    fn render<'a>(&self, app: &AppContext) -> ElementBox;
1470    fn on_focus(&mut self, app: &mut MutableAppContext, window_id: usize, view_id: usize);
1471    fn on_blur(&mut self, app: &mut MutableAppContext, window_id: usize, view_id: usize);
1472    fn keymap_context(&self, app: &AppContext) -> keymap::Context;
1473}
1474
1475impl<T> AnyView for T
1476where
1477    T: View,
1478{
1479    fn as_any(&self) -> &dyn Any {
1480        self
1481    }
1482
1483    fn as_any_mut(&mut self) -> &mut dyn Any {
1484        self
1485    }
1486
1487    fn ui_name(&self) -> &'static str {
1488        T::ui_name()
1489    }
1490
1491    fn render<'a>(&self, app: &AppContext) -> ElementBox {
1492        View::render(self, app)
1493    }
1494
1495    fn on_focus(&mut self, app: &mut MutableAppContext, window_id: usize, view_id: usize) {
1496        let mut ctx = ViewContext::new(app, window_id, view_id);
1497        View::on_focus(self, &mut ctx);
1498    }
1499
1500    fn on_blur(&mut self, app: &mut MutableAppContext, window_id: usize, view_id: usize) {
1501        let mut ctx = ViewContext::new(app, window_id, view_id);
1502        View::on_blur(self, &mut ctx);
1503    }
1504
1505    fn keymap_context(&self, app: &AppContext) -> keymap::Context {
1506        View::keymap_context(self, app)
1507    }
1508}
1509
1510pub struct ModelContext<'a, T: ?Sized> {
1511    app: &'a mut MutableAppContext,
1512    model_id: usize,
1513    model_type: PhantomData<T>,
1514    halt_stream: bool,
1515}
1516
1517impl<'a, T: Entity> ModelContext<'a, T> {
1518    fn new(app: &'a mut MutableAppContext, model_id: usize) -> Self {
1519        Self {
1520            app,
1521            model_id,
1522            model_type: PhantomData,
1523            halt_stream: false,
1524        }
1525    }
1526
1527    pub fn background_executor(&self) -> &Arc<executor::Background> {
1528        &self.app.ctx.background
1529    }
1530
1531    pub fn thread_pool(&self) -> &scoped_pool::Pool {
1532        &self.app.ctx.thread_pool
1533    }
1534
1535    pub fn halt_stream(&mut self) {
1536        self.halt_stream = true;
1537    }
1538
1539    pub fn model_id(&self) -> usize {
1540        self.model_id
1541    }
1542
1543    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
1544    where
1545        S: Entity,
1546        F: FnOnce(&mut ModelContext<S>) -> S,
1547    {
1548        self.app.add_model(build_model)
1549    }
1550
1551    pub fn subscribe<S: Entity, F>(&mut self, handle: &ModelHandle<S>, mut callback: F)
1552    where
1553        S::Event: 'static,
1554        F: 'static + FnMut(&mut T, &S::Event, &mut ModelContext<T>),
1555    {
1556        self.app
1557            .subscriptions
1558            .entry(handle.model_id)
1559            .or_default()
1560            .push(Subscription::FromModel {
1561                model_id: self.model_id,
1562                callback: Box::new(move |model, payload, app, model_id| {
1563                    let model = model.downcast_mut().expect("downcast is type safe");
1564                    let payload = payload.downcast_ref().expect("downcast is type safe");
1565                    let mut ctx = ModelContext::new(app, model_id);
1566                    callback(model, payload, &mut ctx);
1567                }),
1568            });
1569    }
1570
1571    pub fn emit(&mut self, payload: T::Event) {
1572        self.app.pending_effects.push_back(Effect::Event {
1573            entity_id: self.model_id,
1574            payload: Box::new(payload),
1575        });
1576    }
1577
1578    pub fn observe<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F)
1579    where
1580        S: Entity,
1581        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ModelContext<T>),
1582    {
1583        self.app
1584            .model_observations
1585            .entry(handle.model_id)
1586            .or_default()
1587            .push(ModelObservation::FromModel {
1588                model_id: self.model_id,
1589                callback: Box::new(move |model, observed_id, app, model_id| {
1590                    let model = model.downcast_mut().expect("downcast is type safe");
1591                    let observed = ModelHandle::new(observed_id, &app.ctx.ref_counts);
1592                    let mut ctx = ModelContext::new(app, model_id);
1593                    callback(model, observed, &mut ctx);
1594                }),
1595            });
1596    }
1597
1598    pub fn notify(&mut self) {
1599        self.app
1600            .pending_effects
1601            .push_back(Effect::ModelNotification {
1602                model_id: self.model_id,
1603            });
1604    }
1605
1606    fn handle(&self) -> ModelHandle<T> {
1607        ModelHandle::new(self.model_id, &self.app.ctx.ref_counts)
1608    }
1609
1610    pub fn spawn<S, F, U>(&mut self, future: S, callback: F) -> EntityTask<U>
1611    where
1612        S: 'static + Future,
1613        F: 'static + FnOnce(&mut T, S::Output, &mut ModelContext<T>) -> U,
1614        U: 'static,
1615    {
1616        let handle = self.handle();
1617        let weak_handle = handle.downgrade();
1618        let task = self
1619            .app
1620            .spawn::<S, U>(Spawner::Model(handle.into()), future);
1621
1622        self.app.future_handlers.borrow_mut().insert(
1623            task.id,
1624            Box::new(move |output, ctx| {
1625                weak_handle.upgrade(ctx.as_ref()).map(|handle| {
1626                    let output = *output.downcast().unwrap();
1627                    handle.update(ctx, |model, ctx| {
1628                        Box::new(callback(model, output, ctx)) as Box<dyn Any>
1629                    })
1630                })
1631            }),
1632        );
1633
1634        task
1635    }
1636
1637    pub fn spawn_stream<S, F, G, U>(
1638        &mut self,
1639        stream: S,
1640        mut item_callback: F,
1641        done_callback: G,
1642    ) -> EntityTask<U>
1643    where
1644        S: 'static + Stream + Unpin,
1645        F: 'static + FnMut(&mut T, S::Item, &mut ModelContext<T>),
1646        G: 'static + FnOnce(&mut T, &mut ModelContext<T>) -> U,
1647        U: 'static + Any,
1648    {
1649        let handle = self.handle();
1650        let weak_handle = handle.downgrade();
1651        let task = self.app.spawn_stream(Spawner::Model(handle.into()), stream);
1652
1653        self.app.stream_handlers.borrow_mut().insert(
1654            task.id,
1655            StreamHandler {
1656                item_callback: {
1657                    let weak_handle = weak_handle.clone();
1658                    Box::new(move |output, app| {
1659                        if let Some(handle) = weak_handle.upgrade(app.as_ref()) {
1660                            let output = *output.downcast().unwrap();
1661                            handle.update(app, |model, ctx| {
1662                                item_callback(model, output, ctx);
1663                                ctx.halt_stream
1664                            })
1665                        } else {
1666                            true
1667                        }
1668                    })
1669                },
1670                done_callback: Box::new(move |app| {
1671                    weak_handle.upgrade(app.as_ref()).map(|handle| {
1672                        handle.update(app, |model, ctx| Box::new(done_callback(model, ctx)))
1673                            as Box<dyn Any>
1674                    })
1675                }),
1676            },
1677        );
1678
1679        task
1680    }
1681}
1682
1683impl<M> AsRef<AppContext> for ModelContext<'_, M> {
1684    fn as_ref(&self) -> &AppContext {
1685        &self.app.ctx
1686    }
1687}
1688
1689impl<M> AsMut<MutableAppContext> for ModelContext<'_, M> {
1690    fn as_mut(&mut self) -> &mut MutableAppContext {
1691        self.app
1692    }
1693}
1694
1695impl<M> ReadModel for ModelContext<'_, M> {
1696    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
1697        self.app.read_model(handle)
1698    }
1699}
1700
1701impl<M> UpdateModel for ModelContext<'_, M> {
1702    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
1703    where
1704        T: Entity,
1705        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
1706    {
1707        self.app.update_model(handle, update)
1708    }
1709}
1710
1711pub struct ViewContext<'a, T: ?Sized> {
1712    app: &'a mut MutableAppContext,
1713    window_id: usize,
1714    view_id: usize,
1715    view_type: PhantomData<T>,
1716    halt_action_dispatch: bool,
1717    halt_stream: bool,
1718}
1719
1720impl<'a, T: View> ViewContext<'a, T> {
1721    fn new(app: &'a mut MutableAppContext, window_id: usize, view_id: usize) -> Self {
1722        Self {
1723            app,
1724            window_id,
1725            view_id,
1726            view_type: PhantomData,
1727            halt_action_dispatch: true,
1728            halt_stream: false,
1729        }
1730    }
1731
1732    pub fn handle(&self) -> ViewHandle<T> {
1733        ViewHandle::new(self.window_id, self.view_id, &self.app.ctx.ref_counts)
1734    }
1735
1736    pub fn window_id(&self) -> usize {
1737        self.window_id
1738    }
1739
1740    pub fn foreground(&self) -> &Rc<executor::Foreground> {
1741        self.app.foreground_executor()
1742    }
1743
1744    pub fn background_executor(&self) -> &Arc<executor::Background> {
1745        &self.app.ctx.background
1746    }
1747
1748    pub fn debug_elements(&self) -> crate::json::Value {
1749        self.app.debug_elements(self.window_id).unwrap()
1750    }
1751
1752    pub fn focus<S>(&mut self, handle: S)
1753    where
1754        S: Into<AnyViewHandle>,
1755    {
1756        let handle = handle.into();
1757        self.app.pending_effects.push_back(Effect::Focus {
1758            window_id: handle.window_id,
1759            view_id: handle.view_id,
1760        });
1761    }
1762
1763    pub fn focus_self(&mut self) {
1764        self.app.pending_effects.push_back(Effect::Focus {
1765            window_id: self.window_id,
1766            view_id: self.view_id,
1767        });
1768    }
1769
1770    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
1771    where
1772        S: Entity,
1773        F: FnOnce(&mut ModelContext<S>) -> S,
1774    {
1775        self.app.add_model(build_model)
1776    }
1777
1778    pub fn add_view<S, F>(&mut self, build_view: F) -> ViewHandle<S>
1779    where
1780        S: View,
1781        F: FnOnce(&mut ViewContext<S>) -> S,
1782    {
1783        self.app.add_view(self.window_id, build_view)
1784    }
1785
1786    pub fn add_option_view<S, F>(&mut self, build_view: F) -> Option<ViewHandle<S>>
1787    where
1788        S: View,
1789        F: FnOnce(&mut ViewContext<S>) -> Option<S>,
1790    {
1791        self.app.add_option_view(self.window_id, build_view)
1792    }
1793
1794    pub fn subscribe_to_model<E, F>(&mut self, handle: &ModelHandle<E>, mut callback: F)
1795    where
1796        E: Entity,
1797        E::Event: 'static,
1798        F: 'static + FnMut(&mut T, ModelHandle<E>, &E::Event, &mut ViewContext<T>),
1799    {
1800        let emitter_handle = handle.downgrade();
1801        self.app
1802            .subscriptions
1803            .entry(handle.id())
1804            .or_default()
1805            .push(Subscription::FromView {
1806                window_id: self.window_id,
1807                view_id: self.view_id,
1808                callback: Box::new(move |view, payload, app, window_id, view_id| {
1809                    if let Some(emitter_handle) = emitter_handle.upgrade(app.as_ref()) {
1810                        let model = view.downcast_mut().expect("downcast is type safe");
1811                        let payload = payload.downcast_ref().expect("downcast is type safe");
1812                        let mut ctx = ViewContext::new(app, window_id, view_id);
1813                        callback(model, emitter_handle, payload, &mut ctx);
1814                    }
1815                }),
1816            });
1817    }
1818
1819    pub fn subscribe_to_view<V, F>(&mut self, handle: &ViewHandle<V>, mut callback: F)
1820    where
1821        V: View,
1822        V::Event: 'static,
1823        F: 'static + FnMut(&mut T, ViewHandle<V>, &V::Event, &mut ViewContext<T>),
1824    {
1825        let emitter_handle = handle.downgrade();
1826
1827        self.app
1828            .subscriptions
1829            .entry(handle.id())
1830            .or_default()
1831            .push(Subscription::FromView {
1832                window_id: self.window_id,
1833                view_id: self.view_id,
1834                callback: Box::new(move |view, payload, app, window_id, view_id| {
1835                    if let Some(emitter_handle) = emitter_handle.upgrade(&app) {
1836                        let model = view.downcast_mut().expect("downcast is type safe");
1837                        let payload = payload.downcast_ref().expect("downcast is type safe");
1838                        let mut ctx = ViewContext::new(app, window_id, view_id);
1839                        callback(model, emitter_handle, payload, &mut ctx);
1840                    }
1841                }),
1842            });
1843    }
1844
1845    pub fn emit(&mut self, payload: T::Event) {
1846        self.app.pending_effects.push_back(Effect::Event {
1847            entity_id: self.view_id,
1848            payload: Box::new(payload),
1849        });
1850    }
1851
1852    pub fn observe_model<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F)
1853    where
1854        S: Entity,
1855        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ViewContext<T>),
1856    {
1857        self.app
1858            .model_observations
1859            .entry(handle.id())
1860            .or_default()
1861            .push(ModelObservation::FromView {
1862                window_id: self.window_id,
1863                view_id: self.view_id,
1864                callback: Box::new(move |view, observed_id, app, window_id, view_id| {
1865                    let view = view.downcast_mut().expect("downcast is type safe");
1866                    let observed = ModelHandle::new(observed_id, &app.ctx.ref_counts);
1867                    let mut ctx = ViewContext::new(app, window_id, view_id);
1868                    callback(view, observed, &mut ctx);
1869                }),
1870            });
1871    }
1872
1873    pub fn observe_view<S, F>(&mut self, handle: &ViewHandle<S>, mut callback: F)
1874    where
1875        S: View,
1876        F: 'static + FnMut(&mut T, ViewHandle<S>, &mut ViewContext<T>),
1877    {
1878        self.app
1879            .view_observations
1880            .entry(handle.id())
1881            .or_default()
1882            .push(ViewObservation {
1883                window_id: self.window_id,
1884                view_id: self.view_id,
1885                callback: Box::new(
1886                    move |view,
1887                          observed_view_id,
1888                          observed_window_id,
1889                          app,
1890                          observing_window_id,
1891                          observing_view_id| {
1892                        let view = view.downcast_mut().expect("downcast is type safe");
1893                        let observed_handle = ViewHandle::new(
1894                            observed_view_id,
1895                            observed_window_id,
1896                            &app.ctx.ref_counts,
1897                        );
1898                        let mut ctx = ViewContext::new(app, observing_window_id, observing_view_id);
1899                        callback(view, observed_handle, &mut ctx);
1900                    },
1901                ),
1902            });
1903    }
1904
1905    pub fn notify(&mut self) {
1906        self.app.notify_view(self.window_id, self.view_id);
1907    }
1908
1909    pub fn propagate_action(&mut self) {
1910        self.halt_action_dispatch = false;
1911    }
1912
1913    pub fn halt_stream(&mut self) {
1914        self.halt_stream = true;
1915    }
1916
1917    pub fn spawn<S, F, U>(&mut self, future: S, callback: F) -> EntityTask<U>
1918    where
1919        S: 'static + Future,
1920        F: 'static + FnOnce(&mut T, S::Output, &mut ViewContext<T>) -> U,
1921        U: 'static,
1922    {
1923        let handle = self.handle();
1924        let weak_handle = handle.downgrade();
1925        let task = self.app.spawn(Spawner::View(handle.into()), future);
1926
1927        self.app.future_handlers.borrow_mut().insert(
1928            task.id,
1929            Box::new(move |output, app| {
1930                weak_handle.upgrade(app.as_ref()).map(|handle| {
1931                    let output = *output.downcast().unwrap();
1932                    handle.update(app, |view, ctx| {
1933                        Box::new(callback(view, output, ctx)) as Box<dyn Any>
1934                    })
1935                })
1936            }),
1937        );
1938
1939        task
1940    }
1941
1942    pub fn spawn_stream<S, F, G, U>(
1943        &mut self,
1944        stream: S,
1945        mut item_callback: F,
1946        done_callback: G,
1947    ) -> EntityTask<U>
1948    where
1949        S: 'static + Stream + Unpin,
1950        F: 'static + FnMut(&mut T, S::Item, &mut ViewContext<T>),
1951        G: 'static + FnOnce(&mut T, &mut ViewContext<T>) -> U,
1952        U: 'static + Any,
1953    {
1954        let handle = self.handle();
1955        let weak_handle = handle.downgrade();
1956        let task = self.app.spawn_stream(Spawner::View(handle.into()), stream);
1957        self.app.stream_handlers.borrow_mut().insert(
1958            task.id,
1959            StreamHandler {
1960                item_callback: {
1961                    let weak_handle = weak_handle.clone();
1962                    Box::new(move |output, ctx| {
1963                        if let Some(handle) = weak_handle.upgrade(ctx.as_ref()) {
1964                            let output = *output.downcast().unwrap();
1965                            handle.update(ctx, |view, ctx| {
1966                                item_callback(view, output, ctx);
1967                                ctx.halt_stream
1968                            })
1969                        } else {
1970                            true
1971                        }
1972                    })
1973                },
1974                done_callback: Box::new(move |ctx| {
1975                    weak_handle.upgrade(ctx.as_ref()).map(|handle| {
1976                        handle.update(ctx, |view, ctx| {
1977                            Box::new(done_callback(view, ctx)) as Box<dyn Any>
1978                        })
1979                    })
1980                }),
1981            },
1982        );
1983        task
1984    }
1985}
1986
1987impl AsRef<AppContext> for &AppContext {
1988    fn as_ref(&self) -> &AppContext {
1989        self
1990    }
1991}
1992
1993impl<M> AsRef<AppContext> for ViewContext<'_, M> {
1994    fn as_ref(&self) -> &AppContext {
1995        &self.app.ctx
1996    }
1997}
1998
1999impl<M> AsMut<MutableAppContext> for ViewContext<'_, M> {
2000    fn as_mut(&mut self) -> &mut MutableAppContext {
2001        self.app
2002    }
2003}
2004
2005impl<V> ReadModel for ViewContext<'_, V> {
2006    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
2007        self.app.read_model(handle)
2008    }
2009}
2010
2011impl<V: View> UpdateModel for ViewContext<'_, V> {
2012    fn update_model<T, F, S>(&mut self, handle: &ModelHandle<T>, update: F) -> S
2013    where
2014        T: Entity,
2015        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
2016    {
2017        self.app.update_model(handle, update)
2018    }
2019}
2020
2021impl<V: View> ReadView for ViewContext<'_, V> {
2022    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
2023        self.app.read_view(handle)
2024    }
2025}
2026
2027impl<V: View> UpdateView for ViewContext<'_, V> {
2028    fn update_view<T, F, S>(&mut self, handle: &ViewHandle<T>, update: F) -> S
2029    where
2030        T: View,
2031        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
2032    {
2033        self.app.update_view(handle, update)
2034    }
2035}
2036
2037pub trait Handle<T> {
2038    fn id(&self) -> usize;
2039    fn location(&self) -> EntityLocation;
2040}
2041
2042#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
2043pub enum EntityLocation {
2044    Model(usize),
2045    View(usize, usize),
2046}
2047
2048pub struct ModelHandle<T> {
2049    model_id: usize,
2050    model_type: PhantomData<T>,
2051    ref_counts: Weak<Mutex<RefCounts>>,
2052}
2053
2054impl<T: Entity> ModelHandle<T> {
2055    fn new(model_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
2056        ref_counts.lock().inc_entity(model_id);
2057        Self {
2058            model_id,
2059            model_type: PhantomData,
2060            ref_counts: Arc::downgrade(ref_counts),
2061        }
2062    }
2063
2064    fn downgrade(&self) -> WeakModelHandle<T> {
2065        WeakModelHandle::new(self.model_id)
2066    }
2067
2068    pub fn id(&self) -> usize {
2069        self.model_id
2070    }
2071
2072    pub fn read<'a, A: ReadModel>(&self, app: &'a A) -> &'a T {
2073        app.read_model(self)
2074    }
2075
2076    pub fn update<A, F, S>(&self, app: &mut A, update: F) -> S
2077    where
2078        A: UpdateModel,
2079        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
2080    {
2081        app.update_model(self, update)
2082    }
2083
2084    pub fn condition(
2085        &self,
2086        ctx: &TestAppContext,
2087        predicate: impl FnMut(&T, &AppContext) -> bool,
2088    ) -> impl Future<Output = ()> {
2089        self.condition_with_duration(Duration::from_millis(100), ctx, predicate)
2090    }
2091
2092    pub fn condition_with_duration(
2093        &self,
2094        duration: Duration,
2095        ctx: &TestAppContext,
2096        mut predicate: impl FnMut(&T, &AppContext) -> bool,
2097    ) -> impl Future<Output = ()> {
2098        let mut ctx = ctx.0.borrow_mut();
2099        let tx = ctx
2100            .async_observations
2101            .entry(self.id())
2102            .or_insert_with(|| postage::broadcast::channel(128).0);
2103        let mut rx = tx.subscribe();
2104        let ctx = ctx.weak_self.as_ref().unwrap().upgrade().unwrap();
2105        let handle = self.downgrade();
2106
2107        async move {
2108            timeout(duration, async move {
2109                loop {
2110                    {
2111                        let ctx = ctx.borrow();
2112                        let ctx = ctx.as_ref();
2113                        if predicate(
2114                            handle
2115                                .upgrade(ctx)
2116                                .expect("model dropped with pending condition")
2117                                .read(ctx),
2118                            ctx,
2119                        ) {
2120                            break;
2121                        }
2122                    }
2123
2124                    rx.recv()
2125                        .await
2126                        .expect("model dropped with pending condition");
2127                }
2128            })
2129            .await
2130            .expect("condition timed out");
2131        }
2132    }
2133}
2134
2135impl<T> Clone for ModelHandle<T> {
2136    fn clone(&self) -> Self {
2137        if let Some(ref_counts) = self.ref_counts.upgrade() {
2138            ref_counts.lock().inc_entity(self.model_id);
2139        }
2140
2141        Self {
2142            model_id: self.model_id,
2143            model_type: PhantomData,
2144            ref_counts: self.ref_counts.clone(),
2145        }
2146    }
2147}
2148
2149impl<T> PartialEq for ModelHandle<T> {
2150    fn eq(&self, other: &Self) -> bool {
2151        self.model_id == other.model_id
2152    }
2153}
2154
2155impl<T> Eq for ModelHandle<T> {}
2156
2157impl<T> Hash for ModelHandle<T> {
2158    fn hash<H: Hasher>(&self, state: &mut H) {
2159        self.model_id.hash(state);
2160    }
2161}
2162
2163impl<T> std::borrow::Borrow<usize> for ModelHandle<T> {
2164    fn borrow(&self) -> &usize {
2165        &self.model_id
2166    }
2167}
2168
2169impl<T> Debug for ModelHandle<T> {
2170    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2171        f.debug_tuple(&format!("ModelHandle<{}>", type_name::<T>()))
2172            .field(&self.model_id)
2173            .finish()
2174    }
2175}
2176
2177unsafe impl<T> Send for ModelHandle<T> {}
2178unsafe impl<T> Sync for ModelHandle<T> {}
2179
2180impl<T> Drop for ModelHandle<T> {
2181    fn drop(&mut self) {
2182        if let Some(ref_counts) = self.ref_counts.upgrade() {
2183            ref_counts.lock().dec_model(self.model_id);
2184        }
2185    }
2186}
2187
2188impl<T> Handle<T> for ModelHandle<T> {
2189    fn id(&self) -> usize {
2190        self.model_id
2191    }
2192
2193    fn location(&self) -> EntityLocation {
2194        EntityLocation::Model(self.model_id)
2195    }
2196}
2197
2198pub struct WeakModelHandle<T> {
2199    model_id: usize,
2200    model_type: PhantomData<T>,
2201}
2202
2203impl<T: Entity> WeakModelHandle<T> {
2204    fn new(model_id: usize) -> Self {
2205        Self {
2206            model_id,
2207            model_type: PhantomData,
2208        }
2209    }
2210
2211    pub fn upgrade(&self, app: &AppContext) -> Option<ModelHandle<T>> {
2212        if app.models.contains_key(&self.model_id) {
2213            Some(ModelHandle::new(self.model_id, &app.ref_counts))
2214        } else {
2215            None
2216        }
2217    }
2218}
2219
2220impl<T> Clone for WeakModelHandle<T> {
2221    fn clone(&self) -> Self {
2222        Self {
2223            model_id: self.model_id,
2224            model_type: PhantomData,
2225        }
2226    }
2227}
2228
2229pub struct AnyModelHandle {
2230    model_id: usize,
2231    ref_counts: Weak<Mutex<RefCounts>>,
2232}
2233
2234impl<T: Entity> From<ModelHandle<T>> for AnyModelHandle {
2235    fn from(handle: ModelHandle<T>) -> Self {
2236        if let Some(ref_counts) = handle.ref_counts.upgrade() {
2237            ref_counts.lock().inc_entity(handle.model_id);
2238        }
2239        Self {
2240            model_id: handle.model_id,
2241            ref_counts: handle.ref_counts.clone(),
2242        }
2243    }
2244}
2245
2246impl Drop for AnyModelHandle {
2247    fn drop(&mut self) {
2248        if let Some(ref_counts) = self.ref_counts.upgrade() {
2249            ref_counts.lock().dec_model(self.model_id);
2250        }
2251    }
2252}
2253
2254pub struct ViewHandle<T> {
2255    window_id: usize,
2256    view_id: usize,
2257    view_type: PhantomData<T>,
2258    ref_counts: Weak<Mutex<RefCounts>>,
2259}
2260
2261impl<T: View> ViewHandle<T> {
2262    fn new(window_id: usize, view_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
2263        ref_counts.lock().inc_entity(view_id);
2264        Self {
2265            window_id,
2266            view_id,
2267            view_type: PhantomData,
2268            ref_counts: Arc::downgrade(ref_counts),
2269        }
2270    }
2271
2272    pub fn downgrade(&self) -> WeakViewHandle<T> {
2273        WeakViewHandle::new(self.window_id, self.view_id)
2274    }
2275
2276    pub fn window_id(&self) -> usize {
2277        self.window_id
2278    }
2279
2280    pub fn id(&self) -> usize {
2281        self.view_id
2282    }
2283
2284    pub fn read<'a, A: ReadView>(&self, app: &'a A) -> &'a T {
2285        app.read_view(self)
2286    }
2287
2288    pub fn update<A, F, S>(&self, app: &mut A, update: F) -> S
2289    where
2290        A: UpdateView,
2291        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
2292    {
2293        app.update_view(self, update)
2294    }
2295
2296    pub fn is_focused(&self, app: &AppContext) -> bool {
2297        app.focused_view_id(self.window_id)
2298            .map_or(false, |focused_id| focused_id == self.view_id)
2299    }
2300
2301    pub fn condition(
2302        &self,
2303        ctx: &TestAppContext,
2304        mut predicate: impl 'static + FnMut(&T, &AppContext) -> bool,
2305    ) -> impl 'static + Future<Output = ()> {
2306        let mut ctx = ctx.0.borrow_mut();
2307        let tx = ctx
2308            .async_observations
2309            .entry(self.id())
2310            .or_insert_with(|| postage::broadcast::channel(128).0);
2311        let mut rx = tx.subscribe();
2312        let ctx = ctx.weak_self.as_ref().unwrap().upgrade().unwrap();
2313        let handle = self.downgrade();
2314
2315        async move {
2316            timeout(Duration::from_millis(200), async move {
2317                loop {
2318                    {
2319                        let ctx = ctx.borrow();
2320                        let ctx = ctx.as_ref();
2321                        if predicate(
2322                            handle
2323                                .upgrade(ctx)
2324                                .expect("model dropped with pending condition")
2325                                .read(ctx),
2326                            ctx,
2327                        ) {
2328                            break;
2329                        }
2330                    }
2331
2332                    rx.recv()
2333                        .await
2334                        .expect("model dropped with pending condition");
2335                }
2336            })
2337            .await
2338            .expect("condition timed out");
2339        }
2340    }
2341}
2342
2343impl<T> Clone for ViewHandle<T> {
2344    fn clone(&self) -> Self {
2345        if let Some(ref_counts) = self.ref_counts.upgrade() {
2346            ref_counts.lock().inc_entity(self.view_id);
2347        }
2348
2349        Self {
2350            window_id: self.window_id,
2351            view_id: self.view_id,
2352            view_type: PhantomData,
2353            ref_counts: self.ref_counts.clone(),
2354        }
2355    }
2356}
2357
2358impl<T> PartialEq for ViewHandle<T> {
2359    fn eq(&self, other: &Self) -> bool {
2360        self.window_id == other.window_id && self.view_id == other.view_id
2361    }
2362}
2363
2364impl<T> Eq for ViewHandle<T> {}
2365
2366impl<T> Debug for ViewHandle<T> {
2367    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2368        f.debug_struct(&format!("ViewHandle<{}>", type_name::<T>()))
2369            .field("window_id", &self.window_id)
2370            .field("view_id", &self.view_id)
2371            .finish()
2372    }
2373}
2374
2375impl<T> Drop for ViewHandle<T> {
2376    fn drop(&mut self) {
2377        if let Some(ref_counts) = self.ref_counts.upgrade() {
2378            ref_counts.lock().dec_view(self.window_id, self.view_id);
2379        }
2380    }
2381}
2382
2383impl<T> Handle<T> for ViewHandle<T> {
2384    fn id(&self) -> usize {
2385        self.view_id
2386    }
2387
2388    fn location(&self) -> EntityLocation {
2389        EntityLocation::View(self.window_id, self.view_id)
2390    }
2391}
2392
2393#[derive(Clone)]
2394pub struct AnyViewHandle {
2395    window_id: usize,
2396    view_id: usize,
2397    view_type: TypeId,
2398    ref_counts: Weak<Mutex<RefCounts>>,
2399}
2400
2401impl AnyViewHandle {
2402    pub fn id(&self) -> usize {
2403        self.view_id
2404    }
2405
2406    pub fn is<T: 'static>(&self) -> bool {
2407        TypeId::of::<T>() == self.view_type
2408    }
2409
2410    pub fn downcast<T: View>(self) -> Option<ViewHandle<T>> {
2411        if self.is::<T>() {
2412            if let Some(ref_counts) = self.ref_counts.upgrade() {
2413                return Some(ViewHandle::new(self.window_id, self.view_id, &ref_counts));
2414            }
2415        }
2416        None
2417    }
2418}
2419
2420impl<T: View> From<&ViewHandle<T>> for AnyViewHandle {
2421    fn from(handle: &ViewHandle<T>) -> Self {
2422        if let Some(ref_counts) = handle.ref_counts.upgrade() {
2423            ref_counts.lock().inc_entity(handle.view_id);
2424        }
2425        AnyViewHandle {
2426            window_id: handle.window_id,
2427            view_id: handle.view_id,
2428            view_type: TypeId::of::<T>(),
2429            ref_counts: handle.ref_counts.clone(),
2430        }
2431    }
2432}
2433
2434impl<T: View> From<ViewHandle<T>> for AnyViewHandle {
2435    fn from(handle: ViewHandle<T>) -> Self {
2436        (&handle).into()
2437    }
2438}
2439
2440impl Drop for AnyViewHandle {
2441    fn drop(&mut self) {
2442        if let Some(ref_counts) = self.ref_counts.upgrade() {
2443            ref_counts.lock().dec_view(self.window_id, self.view_id);
2444        }
2445    }
2446}
2447
2448pub struct WeakViewHandle<T> {
2449    window_id: usize,
2450    view_id: usize,
2451    view_type: PhantomData<T>,
2452}
2453
2454impl<T: View> WeakViewHandle<T> {
2455    fn new(window_id: usize, view_id: usize) -> Self {
2456        Self {
2457            window_id,
2458            view_id,
2459            view_type: PhantomData,
2460        }
2461    }
2462
2463    pub fn upgrade(&self, ctx: impl AsRef<AppContext>) -> Option<ViewHandle<T>> {
2464        let ctx = ctx.as_ref();
2465        if ctx.views.get(&(self.window_id, self.view_id)).is_some() {
2466            Some(ViewHandle::new(
2467                self.window_id,
2468                self.view_id,
2469                &ctx.ref_counts,
2470            ))
2471        } else {
2472            None
2473        }
2474    }
2475}
2476
2477impl<T> Clone for WeakViewHandle<T> {
2478    fn clone(&self) -> Self {
2479        Self {
2480            window_id: self.window_id,
2481            view_id: self.view_id,
2482            view_type: PhantomData,
2483        }
2484    }
2485}
2486
2487pub struct ValueHandle<T> {
2488    value_type: PhantomData<T>,
2489    tag_type_id: TypeId,
2490    id: usize,
2491    ref_counts: Weak<Mutex<RefCounts>>,
2492}
2493
2494impl<T: 'static> ValueHandle<T> {
2495    fn new(tag_type_id: TypeId, id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
2496        ref_counts.lock().inc_value(tag_type_id, id);
2497        Self {
2498            value_type: PhantomData,
2499            tag_type_id,
2500            id,
2501            ref_counts: Arc::downgrade(ref_counts),
2502        }
2503    }
2504
2505    pub fn read<R>(&self, ctx: &AppContext, f: impl FnOnce(&T) -> R) -> R {
2506        f(ctx
2507            .values
2508            .read()
2509            .get(&(self.tag_type_id, self.id))
2510            .unwrap()
2511            .downcast_ref()
2512            .unwrap())
2513    }
2514
2515    pub fn update<R>(&self, ctx: &AppContext, f: impl FnOnce(&mut T) -> R) -> R {
2516        f(ctx
2517            .values
2518            .write()
2519            .get_mut(&(self.tag_type_id, self.id))
2520            .unwrap()
2521            .downcast_mut()
2522            .unwrap())
2523    }
2524}
2525
2526impl<T> Drop for ValueHandle<T> {
2527    fn drop(&mut self) {
2528        if let Some(ref_counts) = self.ref_counts.upgrade() {
2529            ref_counts.lock().dec_value(self.tag_type_id, self.id);
2530        }
2531    }
2532}
2533
2534#[derive(Default)]
2535struct RefCounts {
2536    entity_counts: HashMap<usize, usize>,
2537    value_counts: HashMap<(TypeId, usize), usize>,
2538    dropped_models: HashSet<usize>,
2539    dropped_views: HashSet<(usize, usize)>,
2540    dropped_values: HashSet<(TypeId, usize)>,
2541}
2542
2543impl RefCounts {
2544    fn inc_entity(&mut self, model_id: usize) {
2545        *self.entity_counts.entry(model_id).or_insert(0) += 1;
2546    }
2547
2548    fn inc_value(&mut self, tag_type_id: TypeId, id: usize) {
2549        *self.value_counts.entry((tag_type_id, id)).or_insert(0) += 1;
2550    }
2551
2552    fn dec_model(&mut self, model_id: usize) {
2553        let count = self.entity_counts.get_mut(&model_id).unwrap();
2554        *count -= 1;
2555        if *count == 0 {
2556            self.entity_counts.remove(&model_id);
2557            self.dropped_models.insert(model_id);
2558        }
2559    }
2560
2561    fn dec_view(&mut self, window_id: usize, view_id: usize) {
2562        let count = self.entity_counts.get_mut(&view_id).unwrap();
2563        *count -= 1;
2564        if *count == 0 {
2565            self.entity_counts.remove(&view_id);
2566            self.dropped_views.insert((window_id, view_id));
2567        }
2568    }
2569
2570    fn dec_value(&mut self, tag_type_id: TypeId, id: usize) {
2571        let key = (tag_type_id, id);
2572        let count = self.value_counts.get_mut(&key).unwrap();
2573        *count -= 1;
2574        if *count == 0 {
2575            self.value_counts.remove(&key);
2576            self.dropped_values.insert(key);
2577        }
2578    }
2579
2580    fn take_dropped(
2581        &mut self,
2582    ) -> (
2583        HashSet<usize>,
2584        HashSet<(usize, usize)>,
2585        HashSet<(TypeId, usize)>,
2586    ) {
2587        let mut dropped_models = HashSet::new();
2588        let mut dropped_views = HashSet::new();
2589        let mut dropped_values = HashSet::new();
2590        std::mem::swap(&mut self.dropped_models, &mut dropped_models);
2591        std::mem::swap(&mut self.dropped_views, &mut dropped_views);
2592        std::mem::swap(&mut self.dropped_values, &mut dropped_values);
2593        (dropped_models, dropped_views, dropped_values)
2594    }
2595}
2596
2597enum Subscription {
2598    FromModel {
2599        model_id: usize,
2600        callback: Box<dyn FnMut(&mut dyn Any, &dyn Any, &mut MutableAppContext, usize)>,
2601    },
2602    FromView {
2603        window_id: usize,
2604        view_id: usize,
2605        callback: Box<dyn FnMut(&mut dyn Any, &dyn Any, &mut MutableAppContext, usize, usize)>,
2606    },
2607}
2608
2609enum ModelObservation {
2610    FromModel {
2611        model_id: usize,
2612        callback: Box<dyn FnMut(&mut dyn Any, usize, &mut MutableAppContext, usize)>,
2613    },
2614    FromView {
2615        window_id: usize,
2616        view_id: usize,
2617        callback: Box<dyn FnMut(&mut dyn Any, usize, &mut MutableAppContext, usize, usize)>,
2618    },
2619}
2620
2621struct ViewObservation {
2622    window_id: usize,
2623    view_id: usize,
2624    callback: Box<dyn FnMut(&mut dyn Any, usize, usize, &mut MutableAppContext, usize, usize)>,
2625}
2626
2627type FutureHandler = Box<dyn FnOnce(Box<dyn Any>, &mut MutableAppContext) -> Option<Box<dyn Any>>>;
2628
2629struct StreamHandler {
2630    item_callback: Box<dyn FnMut(Box<dyn Any>, &mut MutableAppContext) -> bool>,
2631    done_callback: Box<dyn FnOnce(&mut MutableAppContext) -> Option<Box<dyn Any>>>,
2632}
2633
2634#[must_use]
2635pub struct EntityTask<T> {
2636    id: usize,
2637    task: Option<executor::Task<Option<T>>>,
2638    _spawner: Spawner, // Keeps the spawning entity alive for as long as the task exists
2639    handler_map: TaskHandlerMap,
2640}
2641
2642pub enum Spawner {
2643    Model(AnyModelHandle),
2644    View(AnyViewHandle),
2645}
2646
2647enum TaskHandlerMap {
2648    Detached,
2649    Future(Rc<RefCell<HashMap<usize, FutureHandler>>>),
2650    Stream(Rc<RefCell<HashMap<usize, StreamHandler>>>),
2651}
2652
2653impl<T> EntityTask<T> {
2654    fn new(
2655        id: usize,
2656        task: executor::Task<Option<T>>,
2657        spawner: Spawner,
2658        handler_map: TaskHandlerMap,
2659    ) -> Self {
2660        Self {
2661            id,
2662            task: Some(task),
2663            _spawner: spawner,
2664            handler_map,
2665        }
2666    }
2667
2668    pub fn detach(mut self) {
2669        self.handler_map = TaskHandlerMap::Detached;
2670        self.task.take().unwrap().detach();
2671    }
2672
2673    pub async fn cancel(mut self) -> Option<T> {
2674        let task = self.task.take().unwrap();
2675        task.cancel().await.unwrap()
2676    }
2677}
2678
2679impl<T> Future for EntityTask<T> {
2680    type Output = T;
2681
2682    fn poll(
2683        self: std::pin::Pin<&mut Self>,
2684        ctx: &mut std::task::Context<'_>,
2685    ) -> std::task::Poll<Self::Output> {
2686        let task = unsafe { self.map_unchecked_mut(|task| task.task.as_mut().unwrap()) };
2687        task.poll(ctx).map(|output| output.unwrap())
2688    }
2689}
2690
2691impl<T> Drop for EntityTask<T> {
2692    fn drop(self: &mut Self) {
2693        match &self.handler_map {
2694            TaskHandlerMap::Detached => {
2695                return;
2696            }
2697            TaskHandlerMap::Future(map) => {
2698                map.borrow_mut().remove(&self.id);
2699            }
2700            TaskHandlerMap::Stream(map) => {
2701                map.borrow_mut().remove(&self.id);
2702            }
2703        }
2704    }
2705}
2706
2707#[cfg(test)]
2708mod tests {
2709    use super::*;
2710    use crate::elements::*;
2711    use smol::future::poll_once;
2712
2713    #[test]
2714    fn test_model_handles() {
2715        struct Model {
2716            other: Option<ModelHandle<Model>>,
2717            events: Vec<String>,
2718        }
2719
2720        impl Entity for Model {
2721            type Event = usize;
2722        }
2723
2724        impl Model {
2725            fn new(other: Option<ModelHandle<Self>>, ctx: &mut ModelContext<Self>) -> Self {
2726                if let Some(other) = other.as_ref() {
2727                    ctx.observe(other, |me, _, _| {
2728                        me.events.push("notified".into());
2729                    });
2730                    ctx.subscribe(other, |me, event, _| {
2731                        me.events.push(format!("observed event {}", event));
2732                    });
2733                }
2734
2735                Self {
2736                    other,
2737                    events: Vec::new(),
2738                }
2739            }
2740        }
2741
2742        App::test((), |app| {
2743            let handle_1 = app.add_model(|ctx| Model::new(None, ctx));
2744            let handle_2 = app.add_model(|ctx| Model::new(Some(handle_1.clone()), ctx));
2745            assert_eq!(app.ctx.models.len(), 2);
2746
2747            handle_1.update(app, |model, ctx| {
2748                model.events.push("updated".into());
2749                ctx.emit(1);
2750                ctx.notify();
2751                ctx.emit(2);
2752            });
2753            assert_eq!(handle_1.read(app).events, vec!["updated".to_string()]);
2754            assert_eq!(
2755                handle_2.read(app).events,
2756                vec![
2757                    "observed event 1".to_string(),
2758                    "notified".to_string(),
2759                    "observed event 2".to_string(),
2760                ]
2761            );
2762
2763            handle_2.update(app, |model, _| {
2764                drop(handle_1);
2765                model.other.take();
2766            });
2767
2768            assert_eq!(app.ctx.models.len(), 1);
2769            assert!(app.subscriptions.is_empty());
2770            assert!(app.model_observations.is_empty());
2771        });
2772    }
2773
2774    #[test]
2775    fn test_subscribe_and_emit_from_model() {
2776        #[derive(Default)]
2777        struct Model {
2778            events: Vec<usize>,
2779        }
2780
2781        impl Entity for Model {
2782            type Event = usize;
2783        }
2784
2785        App::test((), |app| {
2786            let handle_1 = app.add_model(|_| Model::default());
2787            let handle_2 = app.add_model(|_| Model::default());
2788            let handle_2b = handle_2.clone();
2789
2790            handle_1.update(app, |_, c| {
2791                c.subscribe(&handle_2, move |model: &mut Model, event, c| {
2792                    model.events.push(*event);
2793
2794                    c.subscribe(&handle_2b, |model, event, _| {
2795                        model.events.push(*event * 2);
2796                    });
2797                });
2798            });
2799
2800            handle_2.update(app, |_, c| c.emit(7));
2801            assert_eq!(handle_1.read(app).events, vec![7]);
2802
2803            handle_2.update(app, |_, c| c.emit(5));
2804            assert_eq!(handle_1.read(app).events, vec![7, 10, 5]);
2805        })
2806    }
2807
2808    #[test]
2809    fn test_observe_and_notify_from_model() {
2810        #[derive(Default)]
2811        struct Model {
2812            count: usize,
2813            events: Vec<usize>,
2814        }
2815
2816        impl Entity for Model {
2817            type Event = ();
2818        }
2819
2820        App::test((), |app| {
2821            let handle_1 = app.add_model(|_| Model::default());
2822            let handle_2 = app.add_model(|_| Model::default());
2823            let handle_2b = handle_2.clone();
2824
2825            handle_1.update(app, |_, c| {
2826                c.observe(&handle_2, move |model, observed, c| {
2827                    model.events.push(observed.read(c).count);
2828                    c.observe(&handle_2b, |model, observed, c| {
2829                        model.events.push(observed.read(c).count * 2);
2830                    });
2831                });
2832            });
2833
2834            handle_2.update(app, |model, c| {
2835                model.count = 7;
2836                c.notify()
2837            });
2838            assert_eq!(handle_1.read(app).events, vec![7]);
2839
2840            handle_2.update(app, |model, c| {
2841                model.count = 5;
2842                c.notify()
2843            });
2844            assert_eq!(handle_1.read(app).events, vec![7, 10, 5])
2845        })
2846    }
2847
2848    #[test]
2849    fn test_spawn_from_model() {
2850        #[derive(Default)]
2851        struct Model {
2852            count: usize,
2853        }
2854
2855        impl Entity for Model {
2856            type Event = ();
2857        }
2858
2859        App::test_async((), |mut app| async move {
2860            let handle = app.add_model(|_| Model::default());
2861            handle
2862                .update(&mut app, |_, c| {
2863                    c.spawn(async { 7 }, |model, output, _| {
2864                        model.count = output;
2865                    })
2866                })
2867                .await;
2868            app.read(|ctx| assert_eq!(handle.read(ctx).count, 7));
2869
2870            handle
2871                .update(&mut app, |_, c| {
2872                    c.spawn(async { 14 }, |model, output, _| {
2873                        model.count = output;
2874                    })
2875                })
2876                .await;
2877            app.read(|ctx| assert_eq!(handle.read(ctx).count, 14));
2878        });
2879    }
2880
2881    #[test]
2882    fn test_spawn_stream_local_from_model() {
2883        #[derive(Default)]
2884        struct Model {
2885            events: Vec<Option<usize>>,
2886        }
2887
2888        impl Entity for Model {
2889            type Event = ();
2890        }
2891
2892        App::test_async((), |mut app| async move {
2893            let handle = app.add_model(|_| Model::default());
2894            handle
2895                .update(&mut app, |_, c| {
2896                    c.spawn_stream(
2897                        smol::stream::iter(vec![1, 2, 3]),
2898                        |model, output, _| {
2899                            model.events.push(Some(output));
2900                        },
2901                        |model, _| {
2902                            model.events.push(None);
2903                        },
2904                    )
2905                })
2906                .await;
2907            app.read(|ctx| assert_eq!(handle.read(ctx).events, [Some(1), Some(2), Some(3), None]));
2908        })
2909    }
2910
2911    #[test]
2912    fn test_view_handles() {
2913        struct View {
2914            other: Option<ViewHandle<View>>,
2915            events: Vec<String>,
2916        }
2917
2918        impl Entity for View {
2919            type Event = usize;
2920        }
2921
2922        impl super::View for View {
2923            fn render<'a>(&self, _: &AppContext) -> ElementBox {
2924                Empty::new().boxed()
2925            }
2926
2927            fn ui_name() -> &'static str {
2928                "View"
2929            }
2930        }
2931
2932        impl View {
2933            fn new(other: Option<ViewHandle<View>>, ctx: &mut ViewContext<Self>) -> Self {
2934                if let Some(other) = other.as_ref() {
2935                    ctx.subscribe_to_view(other, |me, _, event, _| {
2936                        me.events.push(format!("observed event {}", event));
2937                    });
2938                }
2939                Self {
2940                    other,
2941                    events: Vec::new(),
2942                }
2943            }
2944        }
2945
2946        App::test((), |app| {
2947            let (window_id, _) = app.add_window(|ctx| View::new(None, ctx));
2948            let handle_1 = app.add_view(window_id, |ctx| View::new(None, ctx));
2949            let handle_2 = app.add_view(window_id, |ctx| View::new(Some(handle_1.clone()), ctx));
2950            assert_eq!(app.ctx.views.len(), 3);
2951
2952            handle_1.update(app, |view, ctx| {
2953                view.events.push("updated".into());
2954                ctx.emit(1);
2955                ctx.emit(2);
2956            });
2957            assert_eq!(handle_1.read(app).events, vec!["updated".to_string()]);
2958            assert_eq!(
2959                handle_2.read(app).events,
2960                vec![
2961                    "observed event 1".to_string(),
2962                    "observed event 2".to_string(),
2963                ]
2964            );
2965
2966            handle_2.update(app, |view, _| {
2967                drop(handle_1);
2968                view.other.take();
2969            });
2970
2971            assert_eq!(app.ctx.views.len(), 2);
2972            assert!(app.subscriptions.is_empty());
2973            assert!(app.model_observations.is_empty());
2974        })
2975    }
2976
2977    #[test]
2978    fn test_subscribe_and_emit_from_view() {
2979        #[derive(Default)]
2980        struct View {
2981            events: Vec<usize>,
2982        }
2983
2984        impl Entity for View {
2985            type Event = usize;
2986        }
2987
2988        impl super::View for View {
2989            fn render<'a>(&self, _: &AppContext) -> ElementBox {
2990                Empty::new().boxed()
2991            }
2992
2993            fn ui_name() -> &'static str {
2994                "View"
2995            }
2996        }
2997
2998        struct Model;
2999
3000        impl Entity for Model {
3001            type Event = usize;
3002        }
3003
3004        App::test((), |app| {
3005            let (window_id, handle_1) = app.add_window(|_| View::default());
3006            let handle_2 = app.add_view(window_id, |_| View::default());
3007            let handle_2b = handle_2.clone();
3008            let handle_3 = app.add_model(|_| Model);
3009
3010            handle_1.update(app, |_, c| {
3011                c.subscribe_to_view(&handle_2, move |me, _, event, c| {
3012                    me.events.push(*event);
3013
3014                    c.subscribe_to_view(&handle_2b, |me, _, event, _| {
3015                        me.events.push(*event * 2);
3016                    });
3017                });
3018
3019                c.subscribe_to_model(&handle_3, |me, _, event, _| {
3020                    me.events.push(*event);
3021                })
3022            });
3023
3024            handle_2.update(app, |_, c| c.emit(7));
3025            assert_eq!(handle_1.read(app).events, vec![7]);
3026
3027            handle_2.update(app, |_, c| c.emit(5));
3028            assert_eq!(handle_1.read(app).events, vec![7, 10, 5]);
3029
3030            handle_3.update(app, |_, c| c.emit(9));
3031            assert_eq!(handle_1.read(app).events, vec![7, 10, 5, 9]);
3032        })
3033    }
3034
3035    #[test]
3036    fn test_dropping_subscribers() {
3037        struct View;
3038
3039        impl Entity for View {
3040            type Event = ();
3041        }
3042
3043        impl super::View for View {
3044            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3045                Empty::new().boxed()
3046            }
3047
3048            fn ui_name() -> &'static str {
3049                "View"
3050            }
3051        }
3052
3053        struct Model;
3054
3055        impl Entity for Model {
3056            type Event = ();
3057        }
3058
3059        App::test((), |app| {
3060            let (window_id, _) = app.add_window(|_| View);
3061            let observing_view = app.add_view(window_id, |_| View);
3062            let emitting_view = app.add_view(window_id, |_| View);
3063            let observing_model = app.add_model(|_| Model);
3064            let observed_model = app.add_model(|_| Model);
3065
3066            observing_view.update(app, |_, ctx| {
3067                ctx.subscribe_to_view(&emitting_view, |_, _, _, _| {});
3068                ctx.subscribe_to_model(&observed_model, |_, _, _, _| {});
3069            });
3070            observing_model.update(app, |_, ctx| {
3071                ctx.subscribe(&observed_model, |_, _, _| {});
3072            });
3073
3074            app.update(|| {
3075                drop(observing_view);
3076                drop(observing_model);
3077            });
3078
3079            emitting_view.update(app, |_, ctx| ctx.emit(()));
3080            observed_model.update(app, |_, ctx| ctx.emit(()));
3081        })
3082    }
3083
3084    #[test]
3085    fn test_observe_and_notify_from_view() {
3086        #[derive(Default)]
3087        struct View {
3088            events: Vec<usize>,
3089        }
3090
3091        impl Entity for View {
3092            type Event = usize;
3093        }
3094
3095        impl super::View for View {
3096            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3097                Empty::new().boxed()
3098            }
3099
3100            fn ui_name() -> &'static str {
3101                "View"
3102            }
3103        }
3104
3105        #[derive(Default)]
3106        struct Model {
3107            count: usize,
3108        }
3109
3110        impl Entity for Model {
3111            type Event = ();
3112        }
3113
3114        App::test((), |app| {
3115            let (_, view) = app.add_window(|_| View::default());
3116            let model = app.add_model(|_| Model::default());
3117
3118            view.update(app, |_, c| {
3119                c.observe_model(&model, |me, observed, c| {
3120                    me.events.push(observed.read(c).count)
3121                });
3122            });
3123
3124            model.update(app, |model, c| {
3125                model.count = 11;
3126                c.notify();
3127            });
3128            assert_eq!(view.read(app).events, vec![11]);
3129        })
3130    }
3131
3132    #[test]
3133    fn test_dropping_observers() {
3134        struct View;
3135
3136        impl Entity for View {
3137            type Event = ();
3138        }
3139
3140        impl super::View for View {
3141            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3142                Empty::new().boxed()
3143            }
3144
3145            fn ui_name() -> &'static str {
3146                "View"
3147            }
3148        }
3149
3150        struct Model;
3151
3152        impl Entity for Model {
3153            type Event = ();
3154        }
3155
3156        App::test((), |app| {
3157            let (window_id, _) = app.add_window(|_| View);
3158            let observing_view = app.add_view(window_id, |_| View);
3159            let observing_model = app.add_model(|_| Model);
3160            let observed_model = app.add_model(|_| Model);
3161
3162            observing_view.update(app, |_, ctx| {
3163                ctx.observe_model(&observed_model, |_, _, _| {});
3164            });
3165            observing_model.update(app, |_, ctx| {
3166                ctx.observe(&observed_model, |_, _, _| {});
3167            });
3168
3169            app.update(|| {
3170                drop(observing_view);
3171                drop(observing_model);
3172            });
3173
3174            observed_model.update(app, |_, ctx| ctx.notify());
3175        })
3176    }
3177
3178    #[test]
3179    fn test_focus() {
3180        #[derive(Default)]
3181        struct View {
3182            events: Vec<String>,
3183        }
3184
3185        impl Entity for View {
3186            type Event = String;
3187        }
3188
3189        impl super::View for View {
3190            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3191                Empty::new().boxed()
3192            }
3193
3194            fn ui_name() -> &'static str {
3195                "View"
3196            }
3197
3198            fn on_focus(&mut self, ctx: &mut ViewContext<Self>) {
3199                self.events.push("self focused".into());
3200                ctx.emit("focused".into());
3201            }
3202
3203            fn on_blur(&mut self, ctx: &mut ViewContext<Self>) {
3204                self.events.push("self blurred".into());
3205                ctx.emit("blurred".into());
3206            }
3207        }
3208
3209        App::test((), |app| {
3210            let (window_id, view_1) = app.add_window(|_| View::default());
3211            let view_2 = app.add_view(window_id, |_| View::default());
3212
3213            view_1.update(app, |_, ctx| {
3214                ctx.subscribe_to_view(&view_2, |view_1, _, event, _| {
3215                    view_1.events.push(format!("view 2 {}", event));
3216                });
3217                ctx.focus(&view_2);
3218            });
3219
3220            view_1.update(app, |_, ctx| {
3221                ctx.focus(&view_1);
3222            });
3223
3224            assert_eq!(
3225                view_1.read(app).events,
3226                [
3227                    "self focused".to_string(),
3228                    "self blurred".to_string(),
3229                    "view 2 focused".to_string(),
3230                    "self focused".to_string(),
3231                    "view 2 blurred".to_string(),
3232                ],
3233            );
3234        })
3235    }
3236
3237    #[test]
3238    fn test_spawn_from_view() {
3239        #[derive(Default)]
3240        struct View {
3241            count: usize,
3242        }
3243
3244        impl Entity for View {
3245            type Event = ();
3246        }
3247
3248        impl super::View for View {
3249            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3250                Empty::new().boxed()
3251            }
3252
3253            fn ui_name() -> &'static str {
3254                "View"
3255            }
3256        }
3257
3258        App::test_async((), |mut app| async move {
3259            let handle = app.add_window(|_| View::default()).1;
3260            handle
3261                .update(&mut app, |_, c| {
3262                    c.spawn(async { 7 }, |me, output, _| {
3263                        me.count = output;
3264                    })
3265                })
3266                .await;
3267            app.read(|ctx| assert_eq!(handle.read(ctx).count, 7));
3268            handle
3269                .update(&mut app, |_, c| {
3270                    c.spawn(async { 14 }, |me, output, _| {
3271                        me.count = output;
3272                    })
3273                })
3274                .await;
3275            app.read(|ctx| assert_eq!(handle.read(ctx).count, 14));
3276        });
3277    }
3278
3279    #[test]
3280    fn test_spawn_stream_local_from_view() {
3281        #[derive(Default)]
3282        struct View {
3283            events: Vec<Option<usize>>,
3284        }
3285
3286        impl Entity for View {
3287            type Event = ();
3288        }
3289
3290        impl super::View for View {
3291            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3292                Empty::new().boxed()
3293            }
3294
3295            fn ui_name() -> &'static str {
3296                "View"
3297            }
3298        }
3299
3300        App::test_async((), |mut app| async move {
3301            let (_, handle) = app.add_window(|_| View::default());
3302            handle
3303                .update(&mut app, |_, c| {
3304                    c.spawn_stream(
3305                        smol::stream::iter(vec![1_usize, 2, 3]),
3306                        |me, output, _| {
3307                            me.events.push(Some(output));
3308                        },
3309                        |me, _| {
3310                            me.events.push(None);
3311                        },
3312                    )
3313                })
3314                .await;
3315
3316            app.read(|ctx| assert_eq!(handle.read(ctx).events, [Some(1), Some(2), Some(3), None]))
3317        });
3318    }
3319
3320    #[test]
3321    fn test_dispatch_action() {
3322        struct ViewA {
3323            id: usize,
3324        }
3325
3326        impl Entity for ViewA {
3327            type Event = ();
3328        }
3329
3330        impl View for ViewA {
3331            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3332                Empty::new().boxed()
3333            }
3334
3335            fn ui_name() -> &'static str {
3336                "View"
3337            }
3338        }
3339
3340        struct ViewB {
3341            id: usize,
3342        }
3343
3344        impl Entity for ViewB {
3345            type Event = ();
3346        }
3347
3348        impl View for ViewB {
3349            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3350                Empty::new().boxed()
3351            }
3352
3353            fn ui_name() -> &'static str {
3354                "View"
3355            }
3356        }
3357
3358        struct ActionArg {
3359            foo: String,
3360        }
3361
3362        App::test((), |app| {
3363            let actions = Rc::new(RefCell::new(Vec::new()));
3364
3365            let actions_clone = actions.clone();
3366            app.add_global_action("action", move |_: &ActionArg, _: &mut MutableAppContext| {
3367                actions_clone.borrow_mut().push("global a".to_string());
3368            });
3369
3370            let actions_clone = actions.clone();
3371            app.add_global_action("action", move |_: &ActionArg, _: &mut MutableAppContext| {
3372                actions_clone.borrow_mut().push("global b".to_string());
3373            });
3374
3375            let actions_clone = actions.clone();
3376            app.add_action("action", move |view: &mut ViewA, arg: &ActionArg, ctx| {
3377                assert_eq!(arg.foo, "bar");
3378                ctx.propagate_action();
3379                actions_clone.borrow_mut().push(format!("{} a", view.id));
3380            });
3381
3382            let actions_clone = actions.clone();
3383            app.add_action("action", move |view: &mut ViewA, _: &ActionArg, ctx| {
3384                if view.id != 1 {
3385                    ctx.propagate_action();
3386                }
3387                actions_clone.borrow_mut().push(format!("{} b", view.id));
3388            });
3389
3390            let actions_clone = actions.clone();
3391            app.add_action("action", move |view: &mut ViewB, _: &ActionArg, ctx| {
3392                ctx.propagate_action();
3393                actions_clone.borrow_mut().push(format!("{} c", view.id));
3394            });
3395
3396            let actions_clone = actions.clone();
3397            app.add_action("action", move |view: &mut ViewB, _: &ActionArg, ctx| {
3398                ctx.propagate_action();
3399                actions_clone.borrow_mut().push(format!("{} d", view.id));
3400            });
3401
3402            let (window_id, view_1) = app.add_window(|_| ViewA { id: 1 });
3403            let view_2 = app.add_view(window_id, |_| ViewB { id: 2 });
3404            let view_3 = app.add_view(window_id, |_| ViewA { id: 3 });
3405            let view_4 = app.add_view(window_id, |_| ViewB { id: 4 });
3406
3407            app.dispatch_action(
3408                window_id,
3409                vec![view_1.id(), view_2.id(), view_3.id(), view_4.id()],
3410                "action",
3411                ActionArg { foo: "bar".into() },
3412            );
3413
3414            assert_eq!(
3415                *actions.borrow(),
3416                vec!["4 d", "4 c", "3 b", "3 a", "2 d", "2 c", "1 b"]
3417            );
3418
3419            // Remove view_1, which doesn't propagate the action
3420            actions.borrow_mut().clear();
3421            app.dispatch_action(
3422                window_id,
3423                vec![view_2.id(), view_3.id(), view_4.id()],
3424                "action",
3425                ActionArg { foo: "bar".into() },
3426            );
3427
3428            assert_eq!(
3429                *actions.borrow(),
3430                vec!["4 d", "4 c", "3 b", "3 a", "2 d", "2 c", "global b", "global a"]
3431            );
3432        })
3433    }
3434
3435    #[test]
3436    fn test_dispatch_keystroke() {
3437        use std::cell::Cell;
3438
3439        #[derive(Clone)]
3440        struct ActionArg {
3441            key: String,
3442        }
3443
3444        struct View {
3445            id: usize,
3446            keymap_context: keymap::Context,
3447        }
3448
3449        impl Entity for View {
3450            type Event = ();
3451        }
3452
3453        impl super::View for View {
3454            fn render<'a>(&self, _: &AppContext) -> ElementBox {
3455                Empty::new().boxed()
3456            }
3457
3458            fn ui_name() -> &'static str {
3459                "View"
3460            }
3461
3462            fn keymap_context(&self, _: &AppContext) -> keymap::Context {
3463                self.keymap_context.clone()
3464            }
3465        }
3466
3467        impl View {
3468            fn new(id: usize) -> Self {
3469                View {
3470                    id,
3471                    keymap_context: keymap::Context::default(),
3472                }
3473            }
3474        }
3475
3476        App::test((), |app| {
3477            let mut view_1 = View::new(1);
3478            let mut view_2 = View::new(2);
3479            let mut view_3 = View::new(3);
3480            view_1.keymap_context.set.insert("a".into());
3481            view_2.keymap_context.set.insert("b".into());
3482            view_3.keymap_context.set.insert("c".into());
3483
3484            let (window_id, view_1) = app.add_window(|_| view_1);
3485            let view_2 = app.add_view(window_id, |_| view_2);
3486            let view_3 = app.add_view(window_id, |_| view_3);
3487
3488            // This keymap's only binding dispatches an action on view 2 because that view will have
3489            // "a" and "b" in its context, but not "c".
3490            let binding = keymap::Binding::new("a", "action", Some("a && b && !c"))
3491                .with_arg(ActionArg { key: "a".into() });
3492            app.add_bindings(vec![binding]);
3493
3494            let handled_action = Rc::new(Cell::new(false));
3495            let handled_action_clone = handled_action.clone();
3496            app.add_action("action", move |view: &mut View, arg: &ActionArg, _ctx| {
3497                handled_action_clone.set(true);
3498                assert_eq!(view.id, 2);
3499                assert_eq!(arg.key, "a");
3500            });
3501
3502            app.dispatch_keystroke(
3503                window_id,
3504                vec![view_1.id(), view_2.id(), view_3.id()],
3505                &Keystroke::parse("a").unwrap(),
3506            )
3507            .unwrap();
3508
3509            assert!(handled_action.get());
3510        });
3511    }
3512
3513    #[test]
3514    fn test_model_condition() {
3515        struct Counter(usize);
3516
3517        impl super::Entity for Counter {
3518            type Event = ();
3519        }
3520
3521        impl Counter {
3522            fn inc(&mut self, ctx: &mut ModelContext<Self>) {
3523                self.0 += 1;
3524                ctx.notify();
3525            }
3526        }
3527
3528        App::test_async((), |mut app| async move {
3529            let model = app.add_model(|_| Counter(0));
3530
3531            let condition1 = model.condition(&app, |model, _| model.0 == 2);
3532            let condition2 = model.condition(&app, |model, _| model.0 == 3);
3533            smol::pin!(condition1, condition2);
3534
3535            model.update(&mut app, |model, ctx| model.inc(ctx));
3536            assert_eq!(poll_once(&mut condition1).await, None);
3537            assert_eq!(poll_once(&mut condition2).await, None);
3538
3539            model.update(&mut app, |model, ctx| model.inc(ctx));
3540            assert_eq!(poll_once(&mut condition1).await, Some(()));
3541            assert_eq!(poll_once(&mut condition2).await, None);
3542
3543            model.update(&mut app, |model, ctx| model.inc(ctx));
3544            assert_eq!(poll_once(&mut condition2).await, Some(()));
3545
3546            // Broadcast channel should be removed if no conditions remain on next notification.
3547            model.update(&mut app, |_, ctx| ctx.notify());
3548            app.update(|ctx| assert!(ctx.async_observations.get(&model.id()).is_none()));
3549        });
3550    }
3551
3552    #[test]
3553    #[should_panic]
3554    fn test_model_condition_timeout() {
3555        struct Model;
3556
3557        impl super::Entity for Model {
3558            type Event = ();
3559        }
3560
3561        App::test_async((), |mut app| async move {
3562            let model = app.add_model(|_| Model);
3563            model.condition(&app, |_, _| false).await;
3564        });
3565    }
3566
3567    #[test]
3568    #[should_panic(expected = "model dropped with pending condition")]
3569    fn test_model_condition_panic_on_drop() {
3570        struct Model;
3571
3572        impl super::Entity for Model {
3573            type Event = ();
3574        }
3575
3576        App::test_async((), |mut app| async move {
3577            let model = app.add_model(|_| Model);
3578            let condition = model.condition(&app, |_, _| false);
3579            app.update(|_| drop(model));
3580            condition.await;
3581        });
3582    }
3583
3584    #[test]
3585    fn test_view_condition() {
3586        struct Counter(usize);
3587
3588        impl super::Entity for Counter {
3589            type Event = ();
3590        }
3591
3592        impl super::View for Counter {
3593            fn ui_name() -> &'static str {
3594                "test view"
3595            }
3596
3597            fn render(&self, _: &AppContext) -> ElementBox {
3598                Empty::new().boxed()
3599            }
3600        }
3601
3602        impl Counter {
3603            fn inc(&mut self, ctx: &mut ViewContext<Self>) {
3604                self.0 += 1;
3605                ctx.notify();
3606            }
3607        }
3608
3609        App::test_async((), |mut app| async move {
3610            let (_, view) = app.add_window(|_| Counter(0));
3611
3612            let condition1 = view.condition(&app, |view, _| view.0 == 2);
3613            let condition2 = view.condition(&app, |view, _| view.0 == 3);
3614            smol::pin!(condition1, condition2);
3615
3616            view.update(&mut app, |view, ctx| view.inc(ctx));
3617            assert_eq!(poll_once(&mut condition1).await, None);
3618            assert_eq!(poll_once(&mut condition2).await, None);
3619
3620            view.update(&mut app, |view, ctx| view.inc(ctx));
3621            assert_eq!(poll_once(&mut condition1).await, Some(()));
3622            assert_eq!(poll_once(&mut condition2).await, None);
3623
3624            view.update(&mut app, |view, ctx| view.inc(ctx));
3625            assert_eq!(poll_once(&mut condition2).await, Some(()));
3626
3627            // Broadcast channel should be removed if no conditions remain on next notification.
3628            view.update(&mut app, |_, ctx| ctx.notify());
3629            app.update(|ctx| assert!(ctx.async_observations.get(&view.id()).is_none()));
3630        });
3631    }
3632
3633    #[test]
3634    #[should_panic]
3635    fn test_view_condition_timeout() {
3636        struct View;
3637
3638        impl super::Entity for View {
3639            type Event = ();
3640        }
3641
3642        impl super::View for View {
3643            fn ui_name() -> &'static str {
3644                "test view"
3645            }
3646
3647            fn render(&self, _: &AppContext) -> ElementBox {
3648                Empty::new().boxed()
3649            }
3650        }
3651
3652        App::test_async((), |mut app| async move {
3653            let (_, view) = app.add_window(|_| View);
3654            view.condition(&app, |_, _| false).await;
3655        });
3656    }
3657
3658    #[test]
3659    #[should_panic(expected = "model dropped with pending condition")]
3660    fn test_view_condition_panic_on_drop() {
3661        struct View;
3662
3663        impl super::Entity for View {
3664            type Event = ();
3665        }
3666
3667        impl super::View for View {
3668            fn ui_name() -> &'static str {
3669                "test view"
3670            }
3671
3672            fn render(&self, _: &AppContext) -> ElementBox {
3673                Empty::new().boxed()
3674            }
3675        }
3676
3677        App::test_async((), |mut app| async move {
3678            let window_id = app.add_window(|_| View).0;
3679            let view = app.add_view(window_id, |_| View);
3680
3681            let condition = view.condition(&app, |_, _| false);
3682            app.update(|_| drop(view));
3683            condition.await;
3684        });
3685    }
3686
3687    // #[test]
3688    // fn test_ui_and_window_updates() {
3689    //     struct View {
3690    //         count: usize,
3691    //     }
3692
3693    //     impl Entity for View {
3694    //         type Event = ();
3695    //     }
3696
3697    //     impl super::View for View {
3698    //         fn render<'a>(&self, _: &AppContext) -> ElementBox {
3699    //             Empty::new().boxed()
3700    //         }
3701
3702    //         fn ui_name() -> &'static str {
3703    //             "View"
3704    //         }
3705    //     }
3706
3707    //     App::test(|app| async move {
3708    //         let (window_id, _) = app.add_window(|_| View { count: 3 });
3709    //         let view_1 = app.add_view(window_id, |_| View { count: 1 });
3710    //         let view_2 = app.add_view(window_id, |_| View { count: 2 });
3711
3712    //         // Ensure that registering for UI updates after mutating the app still gives us all the
3713    //         // updates.
3714    //         let ui_updates = Rc::new(RefCell::new(Vec::new()));
3715    //         let ui_updates_ = ui_updates.clone();
3716    //         app.on_ui_update(move |update, _| ui_updates_.borrow_mut().push(update));
3717
3718    //         assert_eq!(
3719    //             ui_updates.borrow_mut().drain(..).collect::<Vec<_>>(),
3720    //             vec![UiUpdate::OpenWindow {
3721    //                 window_id,
3722    //                 width: 1024.0,
3723    //                 height: 768.0,
3724    //             }]
3725    //         );
3726
3727    //         let window_invalidations = Rc::new(RefCell::new(Vec::new()));
3728    //         let window_invalidations_ = window_invalidations.clone();
3729    //         app.on_window_invalidated(window_id, move |update, _| {
3730    //             window_invalidations_.borrow_mut().push(update)
3731    //         });
3732
3733    //         let view_2_id = view_2.id();
3734    //         view_1.update(app, |view, ctx| {
3735    //             view.count = 7;
3736    //             ctx.notify();
3737    //             drop(view_2);
3738    //         });
3739
3740    //         let invalidation = window_invalidations.borrow_mut().drain(..).next().unwrap();
3741    //         assert_eq!(invalidation.updated.len(), 1);
3742    //         assert!(invalidation.updated.contains(&view_1.id()));
3743    //         assert_eq!(invalidation.removed, vec![view_2_id]);
3744
3745    //         let view_3 = view_1.update(app, |_, ctx| ctx.add_view(|_| View { count: 8 }));
3746
3747    //         let invalidation = window_invalidations.borrow_mut().drain(..).next().unwrap();
3748    //         assert_eq!(invalidation.updated.len(), 1);
3749    //         assert!(invalidation.updated.contains(&view_3.id()));
3750    //         assert!(invalidation.removed.is_empty());
3751
3752    //         view_3
3753    //             .update(app, |_, ctx| {
3754    //                 ctx.spawn_local(async { 9 }, |me, output, ctx| {
3755    //                     me.count = output;
3756    //                     ctx.notify();
3757    //                 })
3758    //             })
3759    //             .await;
3760
3761    //         let invalidation = window_invalidations.borrow_mut().drain(..).next().unwrap();
3762    //         assert_eq!(invalidation.updated.len(), 1);
3763    //         assert!(invalidation.updated.contains(&view_3.id()));
3764    //         assert!(invalidation.removed.is_empty());
3765    //     });
3766    // }
3767}