app.rs

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