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