app.rs

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