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