app.rs

   1pub mod action;
   2
   3use crate::{
   4    elements::ElementBox,
   5    executor::{self, Task},
   6    geometry::rect::RectF,
   7    keymap::{self, Binding, Keystroke},
   8    platform::{self, KeyDownEvent, Platform, PromptLevel, WindowOptions},
   9    presenter::Presenter,
  10    util::post_inc,
  11    AssetCache, AssetSource, ClipboardItem, FontCache, InputHandler, MouseRegionId,
  12    PathPromptOptions, TextLayoutCache,
  13};
  14pub use action::*;
  15use anyhow::{anyhow, Context, Result};
  16use collections::btree_map;
  17use keymap::MatchResult;
  18use lazy_static::lazy_static;
  19use parking_lot::Mutex;
  20use platform::Event;
  21use postage::oneshot;
  22use smallvec::SmallVec;
  23use smol::prelude::*;
  24use std::{
  25    any::{type_name, Any, TypeId},
  26    cell::RefCell,
  27    collections::{hash_map::Entry, BTreeMap, HashMap, HashSet, VecDeque},
  28    fmt::{self, Debug},
  29    hash::{Hash, Hasher},
  30    marker::PhantomData,
  31    mem,
  32    ops::{Deref, DerefMut, Range},
  33    path::{Path, PathBuf},
  34    pin::Pin,
  35    rc::{self, Rc},
  36    sync::{Arc, Weak},
  37    time::Duration,
  38};
  39
  40pub trait Entity: 'static {
  41    type Event;
  42
  43    fn release(&mut self, _: &mut MutableAppContext) {}
  44    fn app_will_quit(
  45        &mut self,
  46        _: &mut MutableAppContext,
  47    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
  48        None
  49    }
  50}
  51
  52pub trait View: Entity + Sized {
  53    fn ui_name() -> &'static str;
  54    fn render(&mut self, cx: &mut RenderContext<'_, Self>) -> ElementBox;
  55    fn on_focus(&mut self, _: &mut ViewContext<Self>) {}
  56    fn on_blur(&mut self, _: &mut ViewContext<Self>) {}
  57    fn keymap_context(&self, _: &AppContext) -> keymap::Context {
  58        Self::default_keymap_context()
  59    }
  60    fn default_keymap_context() -> keymap::Context {
  61        let mut cx = keymap::Context::default();
  62        cx.set.insert(Self::ui_name().into());
  63        cx
  64    }
  65    fn debug_json(&self, _: &AppContext) -> serde_json::Value {
  66        serde_json::Value::Null
  67    }
  68
  69    fn text_for_range(&self, _: Range<usize>, _: &AppContext) -> Option<String> {
  70        None
  71    }
  72    fn selected_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
  73        None
  74    }
  75    fn marked_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
  76        None
  77    }
  78    fn unmark_text(&mut self, _: &mut ViewContext<Self>) {}
  79    fn replace_text_in_range(
  80        &mut self,
  81        _: Option<Range<usize>>,
  82        _: &str,
  83        _: &mut ViewContext<Self>,
  84    ) {
  85    }
  86    fn replace_and_mark_text_in_range(
  87        &mut self,
  88        _: Option<Range<usize>>,
  89        _: &str,
  90        _: Option<Range<usize>>,
  91        _: &mut ViewContext<Self>,
  92    ) {
  93    }
  94}
  95
  96pub trait ReadModel {
  97    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T;
  98}
  99
 100pub trait ReadModelWith {
 101    fn read_model_with<E: Entity, T>(
 102        &self,
 103        handle: &ModelHandle<E>,
 104        read: &mut dyn FnMut(&E, &AppContext) -> T,
 105    ) -> T;
 106}
 107
 108pub trait UpdateModel {
 109    fn update_model<T: Entity, O>(
 110        &mut self,
 111        handle: &ModelHandle<T>,
 112        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
 113    ) -> O;
 114}
 115
 116pub trait UpgradeModelHandle {
 117    fn upgrade_model_handle<T: Entity>(
 118        &self,
 119        handle: &WeakModelHandle<T>,
 120    ) -> Option<ModelHandle<T>>;
 121
 122    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool;
 123
 124    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle>;
 125}
 126
 127pub trait UpgradeViewHandle {
 128    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>>;
 129
 130    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle>;
 131}
 132
 133pub trait ReadView {
 134    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T;
 135}
 136
 137pub trait ReadViewWith {
 138    fn read_view_with<V, T>(
 139        &self,
 140        handle: &ViewHandle<V>,
 141        read: &mut dyn FnMut(&V, &AppContext) -> T,
 142    ) -> T
 143    where
 144        V: View;
 145}
 146
 147pub trait UpdateView {
 148    fn update_view<T, S>(
 149        &mut self,
 150        handle: &ViewHandle<T>,
 151        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
 152    ) -> S
 153    where
 154        T: View;
 155}
 156
 157pub struct Menu<'a> {
 158    pub name: &'a str,
 159    pub items: Vec<MenuItem<'a>>,
 160}
 161
 162pub enum MenuItem<'a> {
 163    Separator,
 164    Submenu(Menu<'a>),
 165    Action {
 166        name: &'a str,
 167        action: Box<dyn Action>,
 168    },
 169}
 170
 171#[derive(Clone)]
 172pub struct App(Rc<RefCell<MutableAppContext>>);
 173
 174#[derive(Clone)]
 175pub struct AsyncAppContext(Rc<RefCell<MutableAppContext>>);
 176
 177#[cfg(any(test, feature = "test-support"))]
 178pub struct TestAppContext {
 179    cx: Rc<RefCell<MutableAppContext>>,
 180    foreground_platform: Rc<platform::test::ForegroundPlatform>,
 181    condition_duration: Option<Duration>,
 182}
 183
 184pub struct WindowInputHandler {
 185    app: Rc<RefCell<MutableAppContext>>,
 186    window_id: usize,
 187}
 188
 189impl App {
 190    pub fn new(asset_source: impl AssetSource) -> Result<Self> {
 191        let platform = platform::current::platform();
 192        let foreground_platform = platform::current::foreground_platform();
 193        let foreground = Rc::new(executor::Foreground::platform(platform.dispatcher())?);
 194        let app = Self(Rc::new(RefCell::new(MutableAppContext::new(
 195            foreground,
 196            Arc::new(executor::Background::new()),
 197            platform.clone(),
 198            foreground_platform.clone(),
 199            Arc::new(FontCache::new(platform.fonts())),
 200            Default::default(),
 201            asset_source,
 202        ))));
 203
 204        foreground_platform.on_quit(Box::new({
 205            let cx = app.0.clone();
 206            move || {
 207                cx.borrow_mut().quit();
 208            }
 209        }));
 210        foreground_platform.on_will_open_menu(Box::new({
 211            let cx = app.0.clone();
 212            move || {
 213                let mut cx = cx.borrow_mut();
 214                cx.keystroke_matcher.clear_pending();
 215            }
 216        }));
 217        foreground_platform.on_validate_menu_command(Box::new({
 218            let cx = app.0.clone();
 219            move |action| {
 220                let cx = cx.borrow_mut();
 221                !cx.keystroke_matcher.has_pending_keystrokes() && cx.is_action_available(action)
 222            }
 223        }));
 224        foreground_platform.on_menu_command(Box::new({
 225            let cx = app.0.clone();
 226            move |action| {
 227                let mut cx = cx.borrow_mut();
 228                if let Some(key_window_id) = cx.cx.platform.key_window_id() {
 229                    if let Some((presenter, _)) =
 230                        cx.presenters_and_platform_windows.get(&key_window_id)
 231                    {
 232                        let presenter = presenter.clone();
 233                        let path = presenter.borrow().dispatch_path(cx.as_ref());
 234                        cx.dispatch_action_any(key_window_id, &path, action);
 235                    } else {
 236                        cx.dispatch_global_action_any(action);
 237                    }
 238                } else {
 239                    cx.dispatch_global_action_any(action);
 240                }
 241            }
 242        }));
 243
 244        app.0.borrow_mut().weak_self = Some(Rc::downgrade(&app.0));
 245        Ok(app)
 246    }
 247
 248    pub fn background(&self) -> Arc<executor::Background> {
 249        self.0.borrow().background().clone()
 250    }
 251
 252    pub fn on_become_active<F>(self, mut callback: F) -> Self
 253    where
 254        F: 'static + FnMut(&mut MutableAppContext),
 255    {
 256        let cx = self.0.clone();
 257        self.0
 258            .borrow_mut()
 259            .foreground_platform
 260            .on_become_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 261        self
 262    }
 263
 264    pub fn on_resign_active<F>(self, mut callback: F) -> Self
 265    where
 266        F: 'static + FnMut(&mut MutableAppContext),
 267    {
 268        let cx = self.0.clone();
 269        self.0
 270            .borrow_mut()
 271            .foreground_platform
 272            .on_resign_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 273        self
 274    }
 275
 276    pub fn on_quit<F>(&mut self, mut callback: F) -> &mut Self
 277    where
 278        F: 'static + FnMut(&mut MutableAppContext),
 279    {
 280        let cx = self.0.clone();
 281        self.0
 282            .borrow_mut()
 283            .foreground_platform
 284            .on_quit(Box::new(move || callback(&mut *cx.borrow_mut())));
 285        self
 286    }
 287
 288    pub fn on_event<F>(&mut self, mut callback: F) -> &mut Self
 289    where
 290        F: 'static + FnMut(Event, &mut MutableAppContext) -> bool,
 291    {
 292        let cx = self.0.clone();
 293        self.0
 294            .borrow_mut()
 295            .foreground_platform
 296            .on_event(Box::new(move |event| {
 297                callback(event, &mut *cx.borrow_mut())
 298            }));
 299        self
 300    }
 301
 302    pub fn on_open_urls<F>(&mut self, mut callback: F) -> &mut Self
 303    where
 304        F: 'static + FnMut(Vec<String>, &mut MutableAppContext),
 305    {
 306        let cx = self.0.clone();
 307        self.0
 308            .borrow_mut()
 309            .foreground_platform
 310            .on_open_urls(Box::new(move |paths| {
 311                callback(paths, &mut *cx.borrow_mut())
 312            }));
 313        self
 314    }
 315
 316    pub fn run<F>(self, on_finish_launching: F)
 317    where
 318        F: 'static + FnOnce(&mut MutableAppContext),
 319    {
 320        let platform = self.0.borrow().foreground_platform.clone();
 321        platform.run(Box::new(move || {
 322            let mut cx = self.0.borrow_mut();
 323            let cx = &mut *cx;
 324            crate::views::init(cx);
 325            on_finish_launching(cx);
 326        }))
 327    }
 328
 329    pub fn platform(&self) -> Arc<dyn Platform> {
 330        self.0.borrow().platform()
 331    }
 332
 333    pub fn font_cache(&self) -> Arc<FontCache> {
 334        self.0.borrow().cx.font_cache.clone()
 335    }
 336
 337    fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 338        let mut state = self.0.borrow_mut();
 339        let result = state.update(callback);
 340        state.pending_notifications.clear();
 341        result
 342    }
 343}
 344
 345impl WindowInputHandler {
 346    fn read_focused_view<T, F>(&self, f: F) -> Option<T>
 347    where
 348        F: FnOnce(&dyn AnyView, &AppContext) -> T,
 349    {
 350        let app = self.app.borrow();
 351        let view_id = app.focused_view_id(self.window_id)?;
 352        let view = app.cx.views.get(&(self.window_id, view_id))?;
 353        let result = f(view.as_ref(), &app);
 354        Some(result)
 355    }
 356
 357    fn update_focused_view<T, F>(&mut self, f: F) -> Option<T>
 358    where
 359        F: FnOnce(usize, usize, &mut dyn AnyView, &mut MutableAppContext) -> T,
 360    {
 361        let mut app = self.app.borrow_mut();
 362        app.update(|app| {
 363            let view_id = app.focused_view_id(self.window_id)?;
 364            let mut view = app.cx.views.remove(&(self.window_id, view_id))?;
 365            let result = f(self.window_id, view_id, view.as_mut(), &mut *app);
 366            app.cx.views.insert((self.window_id, view_id), view);
 367            Some(result)
 368        })
 369    }
 370}
 371
 372impl InputHandler for WindowInputHandler {
 373    fn text_for_range(&self, range: Range<usize>) -> Option<String> {
 374        self.read_focused_view(|view, cx| view.text_for_range(range.clone(), cx))
 375            .flatten()
 376    }
 377
 378    fn selected_text_range(&self) -> Option<Range<usize>> {
 379        self.read_focused_view(|view, cx| view.selected_text_range(cx))
 380            .flatten()
 381    }
 382
 383    fn replace_text_in_range(&mut self, range: Option<Range<usize>>, text: &str) {
 384        self.update_focused_view(|window_id, view_id, view, cx| {
 385            view.replace_text_in_range(range, text, cx, window_id, view_id);
 386        });
 387    }
 388
 389    fn marked_text_range(&self) -> Option<Range<usize>> {
 390        self.read_focused_view(|view, cx| view.marked_text_range(cx))
 391            .flatten()
 392    }
 393
 394    fn unmark_text(&mut self) {
 395        self.update_focused_view(|window_id, view_id, view, cx| {
 396            view.unmark_text(cx, window_id, view_id);
 397        });
 398    }
 399
 400    fn replace_and_mark_text_in_range(
 401        &mut self,
 402        range: Option<Range<usize>>,
 403        new_text: &str,
 404        new_selected_range: Option<Range<usize>>,
 405    ) {
 406        self.update_focused_view(|window_id, view_id, view, cx| {
 407            view.replace_and_mark_text_in_range(
 408                range,
 409                new_text,
 410                new_selected_range,
 411                cx,
 412                window_id,
 413                view_id,
 414            );
 415        });
 416    }
 417
 418    fn rect_for_range(&self, range_utf16: Range<usize>) -> Option<RectF> {
 419        let app = self.app.borrow();
 420        let (presenter, _) = app.presenters_and_platform_windows.get(&self.window_id)?;
 421        let presenter = presenter.borrow();
 422        presenter.rect_for_text_range(range_utf16, &app)
 423    }
 424}
 425
 426#[cfg(any(test, feature = "test-support"))]
 427impl TestAppContext {
 428    pub fn new(
 429        foreground_platform: Rc<platform::test::ForegroundPlatform>,
 430        platform: Arc<dyn Platform>,
 431        foreground: Rc<executor::Foreground>,
 432        background: Arc<executor::Background>,
 433        font_cache: Arc<FontCache>,
 434        leak_detector: Arc<Mutex<LeakDetector>>,
 435        first_entity_id: usize,
 436    ) -> Self {
 437        let mut cx = MutableAppContext::new(
 438            foreground.clone(),
 439            background,
 440            platform,
 441            foreground_platform.clone(),
 442            font_cache,
 443            RefCounts {
 444                #[cfg(any(test, feature = "test-support"))]
 445                leak_detector,
 446                ..Default::default()
 447            },
 448            (),
 449        );
 450        cx.next_entity_id = first_entity_id;
 451        let cx = TestAppContext {
 452            cx: Rc::new(RefCell::new(cx)),
 453            foreground_platform,
 454            condition_duration: None,
 455        };
 456        cx.cx.borrow_mut().weak_self = Some(Rc::downgrade(&cx.cx));
 457        cx
 458    }
 459
 460    pub fn dispatch_action<A: Action>(&self, window_id: usize, action: A) {
 461        let mut cx = self.cx.borrow_mut();
 462        let dispatch_path = cx
 463            .presenters_and_platform_windows
 464            .get(&window_id)
 465            .unwrap()
 466            .0
 467            .borrow()
 468            .dispatch_path(cx.as_ref());
 469
 470        cx.dispatch_action_any(window_id, &dispatch_path, &action);
 471    }
 472
 473    pub fn dispatch_global_action<A: Action>(&self, action: A) {
 474        self.cx.borrow_mut().dispatch_global_action(action);
 475    }
 476
 477    pub fn dispatch_keystroke(&mut self, window_id: usize, keystroke: Keystroke, is_held: bool) {
 478        let handled = self.cx.borrow_mut().update(|cx| {
 479            let presenter = cx
 480                .presenters_and_platform_windows
 481                .get(&window_id)
 482                .unwrap()
 483                .0
 484                .clone();
 485            let dispatch_path = presenter.borrow().dispatch_path(cx.as_ref());
 486
 487            if cx.dispatch_keystroke(window_id, dispatch_path, &keystroke) {
 488                return true;
 489            }
 490            if presenter.borrow_mut().dispatch_event(
 491                Event::KeyDown(KeyDownEvent {
 492                    keystroke: keystroke.clone(),
 493                    is_held,
 494                }),
 495                cx,
 496            ) {
 497                return true;
 498            }
 499
 500            false
 501        });
 502
 503        if !handled && !keystroke.cmd && !keystroke.ctrl {
 504            WindowInputHandler {
 505                app: self.cx.clone(),
 506                window_id,
 507            }
 508            .replace_text_in_range(None, &keystroke.key)
 509        }
 510    }
 511
 512    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 513    where
 514        T: Entity,
 515        F: FnOnce(&mut ModelContext<T>) -> T,
 516    {
 517        self.cx.borrow_mut().add_model(build_model)
 518    }
 519
 520    pub fn add_window<T, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<T>)
 521    where
 522        T: View,
 523        F: FnOnce(&mut ViewContext<T>) -> T,
 524    {
 525        let (window_id, view) = self
 526            .cx
 527            .borrow_mut()
 528            .add_window(Default::default(), build_root_view);
 529        self.simulate_window_activation(Some(window_id));
 530        (window_id, view)
 531    }
 532
 533    pub fn window_ids(&self) -> Vec<usize> {
 534        self.cx.borrow().window_ids().collect()
 535    }
 536
 537    pub fn root_view<T: View>(&self, window_id: usize) -> Option<ViewHandle<T>> {
 538        self.cx.borrow().root_view(window_id)
 539    }
 540
 541    pub fn add_view<T, F>(&mut self, window_id: usize, build_view: F) -> ViewHandle<T>
 542    where
 543        T: View,
 544        F: FnOnce(&mut ViewContext<T>) -> T,
 545    {
 546        self.cx.borrow_mut().add_view(window_id, build_view)
 547    }
 548
 549    pub fn add_option_view<T, F>(
 550        &mut self,
 551        window_id: usize,
 552        build_view: F,
 553    ) -> Option<ViewHandle<T>>
 554    where
 555        T: View,
 556        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
 557    {
 558        self.cx.borrow_mut().add_option_view(window_id, build_view)
 559    }
 560
 561    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 562        callback(self.cx.borrow().as_ref())
 563    }
 564
 565    pub fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 566        let mut state = self.cx.borrow_mut();
 567        // Don't increment pending flushes in order for effects to be flushed before the callback
 568        // completes, which is helpful in tests.
 569        let result = callback(&mut *state);
 570        // Flush effects after the callback just in case there are any. This can happen in edge
 571        // cases such as the closure dropping handles.
 572        state.flush_effects();
 573        result
 574    }
 575
 576    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
 577    where
 578        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
 579        V: View,
 580    {
 581        handle.update(&mut *self.cx.borrow_mut(), |view, cx| {
 582            let mut render_cx = RenderContext {
 583                app: cx,
 584                window_id: handle.window_id(),
 585                view_id: handle.id(),
 586                view_type: PhantomData,
 587                titlebar_height: 0.,
 588                hovered_region_ids: Default::default(),
 589                clicked_region_id: None,
 590                right_clicked_region_id: None,
 591                refreshing: false,
 592            };
 593            f(view, &mut render_cx)
 594        })
 595    }
 596
 597    pub fn to_async(&self) -> AsyncAppContext {
 598        AsyncAppContext(self.cx.clone())
 599    }
 600
 601    pub fn font_cache(&self) -> Arc<FontCache> {
 602        self.cx.borrow().cx.font_cache.clone()
 603    }
 604
 605    pub fn foreground_platform(&self) -> Rc<platform::test::ForegroundPlatform> {
 606        self.foreground_platform.clone()
 607    }
 608
 609    pub fn platform(&self) -> Arc<dyn platform::Platform> {
 610        self.cx.borrow().cx.platform.clone()
 611    }
 612
 613    pub fn foreground(&self) -> Rc<executor::Foreground> {
 614        self.cx.borrow().foreground().clone()
 615    }
 616
 617    pub fn background(&self) -> Arc<executor::Background> {
 618        self.cx.borrow().background().clone()
 619    }
 620
 621    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
 622    where
 623        F: FnOnce(AsyncAppContext) -> Fut,
 624        Fut: 'static + Future<Output = T>,
 625        T: 'static,
 626    {
 627        let foreground = self.foreground();
 628        let future = f(self.to_async());
 629        let cx = self.to_async();
 630        foreground.spawn(async move {
 631            let result = future.await;
 632            cx.0.borrow_mut().flush_effects();
 633            result
 634        })
 635    }
 636
 637    pub fn simulate_new_path_selection(&self, result: impl FnOnce(PathBuf) -> Option<PathBuf>) {
 638        self.foreground_platform.simulate_new_path_selection(result);
 639    }
 640
 641    pub fn did_prompt_for_new_path(&self) -> bool {
 642        self.foreground_platform.as_ref().did_prompt_for_new_path()
 643    }
 644
 645    pub fn simulate_prompt_answer(&self, window_id: usize, answer: usize) {
 646        use postage::prelude::Sink as _;
 647
 648        let mut done_tx = self
 649            .window_mut(window_id)
 650            .pending_prompts
 651            .borrow_mut()
 652            .pop_front()
 653            .expect("prompt was not called");
 654        let _ = done_tx.try_send(answer);
 655    }
 656
 657    pub fn has_pending_prompt(&self, window_id: usize) -> bool {
 658        let window = self.window_mut(window_id);
 659        let prompts = window.pending_prompts.borrow_mut();
 660        !prompts.is_empty()
 661    }
 662
 663    pub fn current_window_title(&self, window_id: usize) -> Option<String> {
 664        self.window_mut(window_id).title.clone()
 665    }
 666
 667    pub fn simulate_window_close(&self, window_id: usize) -> bool {
 668        let handler = self.window_mut(window_id).should_close_handler.take();
 669        if let Some(mut handler) = handler {
 670            let should_close = handler();
 671            self.window_mut(window_id).should_close_handler = Some(handler);
 672            should_close
 673        } else {
 674            false
 675        }
 676    }
 677
 678    pub fn simulate_window_activation(&self, to_activate: Option<usize>) {
 679        let mut handlers = BTreeMap::new();
 680        {
 681            let mut cx = self.cx.borrow_mut();
 682            for (window_id, (_, window)) in &mut cx.presenters_and_platform_windows {
 683                let window = window
 684                    .as_any_mut()
 685                    .downcast_mut::<platform::test::Window>()
 686                    .unwrap();
 687                handlers.insert(
 688                    *window_id,
 689                    mem::take(&mut window.active_status_change_handlers),
 690                );
 691            }
 692        };
 693        let mut handlers = handlers.into_iter().collect::<Vec<_>>();
 694        handlers.sort_unstable_by_key(|(window_id, _)| Some(*window_id) == to_activate);
 695
 696        for (window_id, mut window_handlers) in handlers {
 697            for window_handler in &mut window_handlers {
 698                window_handler(Some(window_id) == to_activate);
 699            }
 700
 701            self.window_mut(window_id)
 702                .active_status_change_handlers
 703                .extend(window_handlers);
 704        }
 705    }
 706
 707    pub fn is_window_edited(&self, window_id: usize) -> bool {
 708        self.window_mut(window_id).edited
 709    }
 710
 711    pub fn leak_detector(&self) -> Arc<Mutex<LeakDetector>> {
 712        self.cx.borrow().leak_detector()
 713    }
 714
 715    pub fn assert_dropped(&self, handle: impl WeakHandle) {
 716        self.cx
 717            .borrow()
 718            .leak_detector()
 719            .lock()
 720            .assert_dropped(handle.id())
 721    }
 722
 723    fn window_mut(&self, window_id: usize) -> std::cell::RefMut<platform::test::Window> {
 724        std::cell::RefMut::map(self.cx.borrow_mut(), |state| {
 725            let (_, window) = state
 726                .presenters_and_platform_windows
 727                .get_mut(&window_id)
 728                .unwrap();
 729            let test_window = window
 730                .as_any_mut()
 731                .downcast_mut::<platform::test::Window>()
 732                .unwrap();
 733            test_window
 734        })
 735    }
 736
 737    pub fn set_condition_duration(&mut self, duration: Option<Duration>) {
 738        self.condition_duration = duration;
 739    }
 740
 741    pub fn condition_duration(&self) -> Duration {
 742        self.condition_duration.unwrap_or_else(|| {
 743            if std::env::var("CI").is_ok() {
 744                Duration::from_secs(2)
 745            } else {
 746                Duration::from_millis(500)
 747            }
 748        })
 749    }
 750
 751    pub fn assert_clipboard_content(&mut self, expected_content: Option<&str>) {
 752        self.update(|cx| {
 753            let actual_content = cx.read_from_clipboard().map(|item| item.text().to_owned());
 754            let expected_content = expected_content.map(|content| content.to_owned());
 755            assert_eq!(actual_content, expected_content);
 756        })
 757    }
 758}
 759
 760impl AsyncAppContext {
 761    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
 762    where
 763        F: FnOnce(AsyncAppContext) -> Fut,
 764        Fut: 'static + Future<Output = T>,
 765        T: 'static,
 766    {
 767        self.0.borrow().foreground.spawn(f(self.clone()))
 768    }
 769
 770    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 771        callback(self.0.borrow().as_ref())
 772    }
 773
 774    pub fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 775        self.0.borrow_mut().update(callback)
 776    }
 777
 778    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 779    where
 780        T: Entity,
 781        F: FnOnce(&mut ModelContext<T>) -> T,
 782    {
 783        self.update(|cx| cx.add_model(build_model))
 784    }
 785
 786    pub fn add_view<T, F>(&mut self, window_id: usize, build_view: F) -> ViewHandle<T>
 787    where
 788        T: View,
 789        F: FnOnce(&mut ViewContext<T>) -> T,
 790    {
 791        self.update(|cx| cx.add_view(window_id, build_view))
 792    }
 793
 794    pub fn add_window<T, F>(
 795        &mut self,
 796        window_options: WindowOptions,
 797        build_root_view: F,
 798    ) -> (usize, ViewHandle<T>)
 799    where
 800        T: View,
 801        F: FnOnce(&mut ViewContext<T>) -> T,
 802    {
 803        self.update(|cx| cx.add_window(window_options, build_root_view))
 804    }
 805
 806    pub fn platform(&self) -> Arc<dyn Platform> {
 807        self.0.borrow().platform()
 808    }
 809
 810    pub fn foreground(&self) -> Rc<executor::Foreground> {
 811        self.0.borrow().foreground.clone()
 812    }
 813
 814    pub fn background(&self) -> Arc<executor::Background> {
 815        self.0.borrow().cx.background.clone()
 816    }
 817}
 818
 819impl UpdateModel for AsyncAppContext {
 820    fn update_model<E: Entity, O>(
 821        &mut self,
 822        handle: &ModelHandle<E>,
 823        update: &mut dyn FnMut(&mut E, &mut ModelContext<E>) -> O,
 824    ) -> O {
 825        self.0.borrow_mut().update_model(handle, update)
 826    }
 827}
 828
 829impl UpgradeModelHandle for AsyncAppContext {
 830    fn upgrade_model_handle<T: Entity>(
 831        &self,
 832        handle: &WeakModelHandle<T>,
 833    ) -> Option<ModelHandle<T>> {
 834        self.0.borrow().upgrade_model_handle(handle)
 835    }
 836
 837    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
 838        self.0.borrow().model_handle_is_upgradable(handle)
 839    }
 840
 841    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
 842        self.0.borrow().upgrade_any_model_handle(handle)
 843    }
 844}
 845
 846impl UpgradeViewHandle for AsyncAppContext {
 847    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
 848        self.0.borrow_mut().upgrade_view_handle(handle)
 849    }
 850
 851    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
 852        self.0.borrow_mut().upgrade_any_view_handle(handle)
 853    }
 854}
 855
 856impl ReadModelWith for AsyncAppContext {
 857    fn read_model_with<E: Entity, T>(
 858        &self,
 859        handle: &ModelHandle<E>,
 860        read: &mut dyn FnMut(&E, &AppContext) -> T,
 861    ) -> T {
 862        let cx = self.0.borrow();
 863        let cx = cx.as_ref();
 864        read(handle.read(cx), cx)
 865    }
 866}
 867
 868impl UpdateView for AsyncAppContext {
 869    fn update_view<T, S>(
 870        &mut self,
 871        handle: &ViewHandle<T>,
 872        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
 873    ) -> S
 874    where
 875        T: View,
 876    {
 877        self.0.borrow_mut().update_view(handle, update)
 878    }
 879}
 880
 881impl ReadViewWith for AsyncAppContext {
 882    fn read_view_with<V, T>(
 883        &self,
 884        handle: &ViewHandle<V>,
 885        read: &mut dyn FnMut(&V, &AppContext) -> T,
 886    ) -> T
 887    where
 888        V: View,
 889    {
 890        let cx = self.0.borrow();
 891        let cx = cx.as_ref();
 892        read(handle.read(cx), cx)
 893    }
 894}
 895
 896#[cfg(any(test, feature = "test-support"))]
 897impl UpdateModel for TestAppContext {
 898    fn update_model<T: Entity, O>(
 899        &mut self,
 900        handle: &ModelHandle<T>,
 901        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
 902    ) -> O {
 903        self.cx.borrow_mut().update_model(handle, update)
 904    }
 905}
 906
 907#[cfg(any(test, feature = "test-support"))]
 908impl ReadModelWith for TestAppContext {
 909    fn read_model_with<E: Entity, T>(
 910        &self,
 911        handle: &ModelHandle<E>,
 912        read: &mut dyn FnMut(&E, &AppContext) -> T,
 913    ) -> T {
 914        let cx = self.cx.borrow();
 915        let cx = cx.as_ref();
 916        read(handle.read(cx), cx)
 917    }
 918}
 919
 920#[cfg(any(test, feature = "test-support"))]
 921impl UpdateView for TestAppContext {
 922    fn update_view<T, S>(
 923        &mut self,
 924        handle: &ViewHandle<T>,
 925        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
 926    ) -> S
 927    where
 928        T: View,
 929    {
 930        self.cx.borrow_mut().update_view(handle, update)
 931    }
 932}
 933
 934#[cfg(any(test, feature = "test-support"))]
 935impl ReadViewWith for TestAppContext {
 936    fn read_view_with<V, T>(
 937        &self,
 938        handle: &ViewHandle<V>,
 939        read: &mut dyn FnMut(&V, &AppContext) -> T,
 940    ) -> T
 941    where
 942        V: View,
 943    {
 944        let cx = self.cx.borrow();
 945        let cx = cx.as_ref();
 946        read(handle.read(cx), cx)
 947    }
 948}
 949
 950type ActionCallback =
 951    dyn FnMut(&mut dyn AnyView, &dyn Action, &mut MutableAppContext, usize, usize);
 952type GlobalActionCallback = dyn FnMut(&dyn Action, &mut MutableAppContext);
 953
 954type SubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut MutableAppContext) -> bool>;
 955type GlobalSubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut MutableAppContext)>;
 956type ObservationCallback = Box<dyn FnMut(&mut MutableAppContext) -> bool>;
 957type FocusObservationCallback = Box<dyn FnMut(bool, &mut MutableAppContext) -> bool>;
 958type GlobalObservationCallback = Box<dyn FnMut(&mut MutableAppContext)>;
 959type ReleaseObservationCallback = Box<dyn FnOnce(&dyn Any, &mut MutableAppContext)>;
 960type ActionObservationCallback = Box<dyn FnMut(TypeId, &mut MutableAppContext)>;
 961type WindowActivationCallback = Box<dyn FnMut(bool, &mut MutableAppContext) -> bool>;
 962type DeserializeActionCallback = fn(json: &str) -> anyhow::Result<Box<dyn Action>>;
 963type WindowShouldCloseSubscriptionCallback = Box<dyn FnMut(&mut MutableAppContext) -> bool>;
 964
 965pub struct MutableAppContext {
 966    weak_self: Option<rc::Weak<RefCell<Self>>>,
 967    foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 968    assets: Arc<AssetCache>,
 969    cx: AppContext,
 970    action_deserializers: HashMap<&'static str, (TypeId, DeserializeActionCallback)>,
 971    capture_actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 972    actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 973    global_actions: HashMap<TypeId, Box<GlobalActionCallback>>,
 974    keystroke_matcher: keymap::Matcher,
 975    next_entity_id: usize,
 976    next_window_id: usize,
 977    next_subscription_id: usize,
 978    frame_count: usize,
 979    subscriptions: Arc<Mutex<HashMap<usize, BTreeMap<usize, Option<SubscriptionCallback>>>>>,
 980    global_subscriptions:
 981        Arc<Mutex<HashMap<TypeId, BTreeMap<usize, Option<GlobalSubscriptionCallback>>>>>,
 982    observations: Arc<Mutex<HashMap<usize, BTreeMap<usize, Option<ObservationCallback>>>>>,
 983    focus_observations:
 984        Arc<Mutex<HashMap<usize, BTreeMap<usize, Option<FocusObservationCallback>>>>>,
 985    global_observations:
 986        Arc<Mutex<HashMap<TypeId, BTreeMap<usize, Option<GlobalObservationCallback>>>>>,
 987    release_observations: Arc<Mutex<HashMap<usize, BTreeMap<usize, ReleaseObservationCallback>>>>,
 988    window_activation_observations:
 989        Arc<Mutex<HashMap<usize, BTreeMap<usize, Option<WindowActivationCallback>>>>>,
 990    action_dispatch_observations: Arc<Mutex<BTreeMap<usize, ActionObservationCallback>>>,
 991    presenters_and_platform_windows:
 992        HashMap<usize, (Rc<RefCell<Presenter>>, Box<dyn platform::Window>)>,
 993    foreground: Rc<executor::Foreground>,
 994    pending_effects: VecDeque<Effect>,
 995    pending_focus_index: Option<usize>,
 996    pending_notifications: HashSet<usize>,
 997    pending_global_notifications: HashSet<TypeId>,
 998    pending_flushes: usize,
 999    flushing_effects: bool,
1000    halt_action_dispatch: bool,
1001}
1002
1003impl MutableAppContext {
1004    fn new(
1005        foreground: Rc<executor::Foreground>,
1006        background: Arc<executor::Background>,
1007        platform: Arc<dyn platform::Platform>,
1008        foreground_platform: Rc<dyn platform::ForegroundPlatform>,
1009        font_cache: Arc<FontCache>,
1010        ref_counts: RefCounts,
1011        asset_source: impl AssetSource,
1012    ) -> Self {
1013        Self {
1014            weak_self: None,
1015            foreground_platform,
1016            assets: Arc::new(AssetCache::new(asset_source)),
1017            cx: AppContext {
1018                models: Default::default(),
1019                views: Default::default(),
1020                windows: Default::default(),
1021                globals: Default::default(),
1022                element_states: Default::default(),
1023                ref_counts: Arc::new(Mutex::new(ref_counts)),
1024                background,
1025                font_cache,
1026                platform,
1027            },
1028            action_deserializers: HashMap::new(),
1029            capture_actions: HashMap::new(),
1030            actions: HashMap::new(),
1031            global_actions: HashMap::new(),
1032            keystroke_matcher: keymap::Matcher::default(),
1033            next_entity_id: 0,
1034            next_window_id: 0,
1035            next_subscription_id: 0,
1036            frame_count: 0,
1037            subscriptions: Default::default(),
1038            global_subscriptions: Default::default(),
1039            observations: Default::default(),
1040            focus_observations: Default::default(),
1041            release_observations: Default::default(),
1042            global_observations: Default::default(),
1043            window_activation_observations: Default::default(),
1044            action_dispatch_observations: Default::default(),
1045            presenters_and_platform_windows: HashMap::new(),
1046            foreground,
1047            pending_effects: VecDeque::new(),
1048            pending_focus_index: None,
1049            pending_notifications: HashSet::new(),
1050            pending_global_notifications: HashSet::new(),
1051            pending_flushes: 0,
1052            flushing_effects: false,
1053            halt_action_dispatch: false,
1054        }
1055    }
1056
1057    pub fn upgrade(&self) -> App {
1058        App(self.weak_self.as_ref().unwrap().upgrade().unwrap())
1059    }
1060
1061    pub fn quit(&mut self) {
1062        let mut futures = Vec::new();
1063        for model_id in self.cx.models.keys().copied().collect::<Vec<_>>() {
1064            let mut model = self.cx.models.remove(&model_id).unwrap();
1065            futures.extend(model.app_will_quit(self));
1066            self.cx.models.insert(model_id, model);
1067        }
1068
1069        for view_id in self.cx.views.keys().copied().collect::<Vec<_>>() {
1070            let mut view = self.cx.views.remove(&view_id).unwrap();
1071            futures.extend(view.app_will_quit(self));
1072            self.cx.views.insert(view_id, view);
1073        }
1074
1075        self.remove_all_windows();
1076
1077        let futures = futures::future::join_all(futures);
1078        if self
1079            .background
1080            .block_with_timeout(Duration::from_millis(100), futures)
1081            .is_err()
1082        {
1083            log::error!("timed out waiting on app_will_quit");
1084        }
1085    }
1086
1087    pub fn remove_all_windows(&mut self) {
1088        for (window_id, _) in self.cx.windows.drain() {
1089            self.presenters_and_platform_windows.remove(&window_id);
1090        }
1091        self.flush_effects();
1092    }
1093
1094    pub fn platform(&self) -> Arc<dyn platform::Platform> {
1095        self.cx.platform.clone()
1096    }
1097
1098    pub fn font_cache(&self) -> &Arc<FontCache> {
1099        &self.cx.font_cache
1100    }
1101
1102    pub fn foreground(&self) -> &Rc<executor::Foreground> {
1103        &self.foreground
1104    }
1105
1106    pub fn background(&self) -> &Arc<executor::Background> {
1107        &self.cx.background
1108    }
1109
1110    pub fn debug_elements(&self, window_id: usize) -> Option<crate::json::Value> {
1111        self.presenters_and_platform_windows
1112            .get(&window_id)
1113            .and_then(|(presenter, _)| presenter.borrow().debug_elements(self))
1114    }
1115
1116    pub fn deserialize_action(
1117        &self,
1118        name: &str,
1119        argument: Option<&str>,
1120    ) -> Result<Box<dyn Action>> {
1121        let callback = self
1122            .action_deserializers
1123            .get(name)
1124            .ok_or_else(|| anyhow!("unknown action {}", name))?
1125            .1;
1126        callback(argument.unwrap_or("{}"))
1127            .with_context(|| format!("invalid data for action {}", name))
1128    }
1129
1130    pub fn add_action<A, V, F>(&mut self, handler: F)
1131    where
1132        A: Action,
1133        V: View,
1134        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
1135    {
1136        self.add_action_internal(handler, false)
1137    }
1138
1139    pub fn capture_action<A, V, F>(&mut self, handler: F)
1140    where
1141        A: Action,
1142        V: View,
1143        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
1144    {
1145        self.add_action_internal(handler, true)
1146    }
1147
1148    fn add_action_internal<A, V, F>(&mut self, mut handler: F, capture: bool)
1149    where
1150        A: Action,
1151        V: View,
1152        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
1153    {
1154        let handler = Box::new(
1155            move |view: &mut dyn AnyView,
1156                  action: &dyn Action,
1157                  cx: &mut MutableAppContext,
1158                  window_id: usize,
1159                  view_id: usize| {
1160                let action = action.as_any().downcast_ref().unwrap();
1161                let mut cx = ViewContext::new(cx, window_id, view_id);
1162                handler(
1163                    view.as_any_mut()
1164                        .downcast_mut()
1165                        .expect("downcast is type safe"),
1166                    action,
1167                    &mut cx,
1168                );
1169            },
1170        );
1171
1172        self.action_deserializers
1173            .entry(A::qualified_name())
1174            .or_insert((TypeId::of::<A>(), A::from_json_str));
1175
1176        let actions = if capture {
1177            &mut self.capture_actions
1178        } else {
1179            &mut self.actions
1180        };
1181
1182        actions
1183            .entry(TypeId::of::<V>())
1184            .or_default()
1185            .entry(TypeId::of::<A>())
1186            .or_default()
1187            .push(handler);
1188    }
1189
1190    pub fn add_async_action<A, V, F>(&mut self, mut handler: F)
1191    where
1192        A: Action,
1193        V: View,
1194        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> Option<Task<Result<()>>>,
1195    {
1196        self.add_action(move |view, action, cx| {
1197            handler(view, action, cx).map(|task| task.detach_and_log_err(cx));
1198        })
1199    }
1200
1201    pub fn add_global_action<A, F>(&mut self, mut handler: F)
1202    where
1203        A: Action,
1204        F: 'static + FnMut(&A, &mut MutableAppContext),
1205    {
1206        let handler = Box::new(move |action: &dyn Action, cx: &mut MutableAppContext| {
1207            let action = action.as_any().downcast_ref().unwrap();
1208            handler(action, cx);
1209        });
1210
1211        self.action_deserializers
1212            .entry(A::qualified_name())
1213            .or_insert((TypeId::of::<A>(), A::from_json_str));
1214
1215        if self
1216            .global_actions
1217            .insert(TypeId::of::<A>(), handler)
1218            .is_some()
1219        {
1220            panic!(
1221                "registered multiple global handlers for {}",
1222                type_name::<A>()
1223            );
1224        }
1225    }
1226
1227    pub fn window_ids(&self) -> impl Iterator<Item = usize> + '_ {
1228        self.cx.windows.keys().cloned()
1229    }
1230
1231    pub fn activate_window(&self, window_id: usize) {
1232        if let Some((_, window)) = self.presenters_and_platform_windows.get(&window_id) {
1233            window.activate()
1234        }
1235    }
1236
1237    pub fn root_view<T: View>(&self, window_id: usize) -> Option<ViewHandle<T>> {
1238        self.cx
1239            .windows
1240            .get(&window_id)
1241            .and_then(|window| window.root_view.clone().downcast::<T>())
1242    }
1243
1244    pub fn window_is_active(&self, window_id: usize) -> bool {
1245        self.cx
1246            .windows
1247            .get(&window_id)
1248            .map_or(false, |window| window.is_active)
1249    }
1250
1251    pub fn render_view(&mut self, params: RenderParams) -> Result<ElementBox> {
1252        let window_id = params.window_id;
1253        let view_id = params.view_id;
1254        let mut view = self
1255            .cx
1256            .views
1257            .remove(&(params.window_id, params.view_id))
1258            .ok_or(anyhow!("view not found"))?;
1259        let element = view.render(params, self);
1260        self.cx.views.insert((window_id, view_id), view);
1261        Ok(element)
1262    }
1263
1264    pub fn render_views(
1265        &mut self,
1266        window_id: usize,
1267        titlebar_height: f32,
1268    ) -> HashMap<usize, ElementBox> {
1269        self.start_frame();
1270        let view_ids = self
1271            .views
1272            .keys()
1273            .filter_map(|(win_id, view_id)| {
1274                if *win_id == window_id {
1275                    Some(*view_id)
1276                } else {
1277                    None
1278                }
1279            })
1280            .collect::<Vec<_>>();
1281        view_ids
1282            .into_iter()
1283            .map(|view_id| {
1284                (
1285                    view_id,
1286                    self.render_view(RenderParams {
1287                        window_id,
1288                        view_id,
1289                        titlebar_height,
1290                        hovered_region_ids: Default::default(),
1291                        clicked_region_id: None,
1292                        right_clicked_region_id: None,
1293                        refreshing: false,
1294                    })
1295                    .unwrap(),
1296                )
1297            })
1298            .collect()
1299    }
1300
1301    pub(crate) fn start_frame(&mut self) {
1302        self.frame_count += 1;
1303    }
1304
1305    pub fn update<T, F: FnOnce(&mut Self) -> T>(&mut self, callback: F) -> T {
1306        self.pending_flushes += 1;
1307        let result = callback(self);
1308        self.flush_effects();
1309        result
1310    }
1311
1312    pub fn set_menus(&mut self, menus: Vec<Menu>) {
1313        self.foreground_platform
1314            .set_menus(menus, &self.keystroke_matcher);
1315    }
1316
1317    fn show_character_palette(&self, window_id: usize) {
1318        let (_, window) = &self.presenters_and_platform_windows[&window_id];
1319        window.show_character_palette();
1320    }
1321
1322    pub fn minimize_window(&self, window_id: usize) {
1323        let (_, window) = &self.presenters_and_platform_windows[&window_id];
1324        window.minimize();
1325    }
1326
1327    pub fn zoom_window(&self, window_id: usize) {
1328        let (_, window) = &self.presenters_and_platform_windows[&window_id];
1329        window.zoom();
1330    }
1331
1332    fn prompt(
1333        &self,
1334        window_id: usize,
1335        level: PromptLevel,
1336        msg: &str,
1337        answers: &[&str],
1338    ) -> oneshot::Receiver<usize> {
1339        let (_, window) = &self.presenters_and_platform_windows[&window_id];
1340        window.prompt(level, msg, answers)
1341    }
1342
1343    pub fn prompt_for_paths(
1344        &self,
1345        options: PathPromptOptions,
1346    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
1347        self.foreground_platform.prompt_for_paths(options)
1348    }
1349
1350    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
1351        self.foreground_platform.prompt_for_new_path(directory)
1352    }
1353
1354    pub fn emit_global<E: Any>(&mut self, payload: E) {
1355        self.pending_effects.push_back(Effect::GlobalEvent {
1356            payload: Box::new(payload),
1357        });
1358    }
1359
1360    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
1361    where
1362        E: Entity,
1363        E::Event: 'static,
1364        H: Handle<E>,
1365        F: 'static + FnMut(H, &E::Event, &mut Self),
1366    {
1367        self.subscribe_internal(handle, move |handle, event, cx| {
1368            callback(handle, event, cx);
1369            true
1370        })
1371    }
1372
1373    pub fn subscribe_global<E, F>(&mut self, mut callback: F) -> Subscription
1374    where
1375        E: Any,
1376        F: 'static + FnMut(&E, &mut Self),
1377    {
1378        let subscription_id = post_inc(&mut self.next_subscription_id);
1379        let type_id = TypeId::of::<E>();
1380        self.pending_effects.push_back(Effect::GlobalSubscription {
1381            type_id,
1382            subscription_id,
1383            callback: Box::new(move |payload, cx| {
1384                let payload = payload.downcast_ref().expect("downcast is type safe");
1385                callback(payload, cx)
1386            }),
1387        });
1388        Subscription::GlobalSubscription {
1389            id: subscription_id,
1390            type_id,
1391            subscriptions: Some(Arc::downgrade(&self.global_subscriptions)),
1392        }
1393    }
1394
1395    pub fn observe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
1396    where
1397        E: Entity,
1398        E::Event: 'static,
1399        H: Handle<E>,
1400        F: 'static + FnMut(H, &mut Self),
1401    {
1402        self.observe_internal(handle, move |handle, cx| {
1403            callback(handle, cx);
1404            true
1405        })
1406    }
1407
1408    pub fn subscribe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
1409    where
1410        E: Entity,
1411        E::Event: 'static,
1412        H: Handle<E>,
1413        F: 'static + FnMut(H, &E::Event, &mut Self) -> bool,
1414    {
1415        let subscription_id = post_inc(&mut self.next_subscription_id);
1416        let emitter = handle.downgrade();
1417        self.pending_effects.push_back(Effect::Subscription {
1418            entity_id: handle.id(),
1419            subscription_id,
1420            callback: Box::new(move |payload, cx| {
1421                if let Some(emitter) = H::upgrade_from(&emitter, cx.as_ref()) {
1422                    let payload = payload.downcast_ref().expect("downcast is type safe");
1423                    callback(emitter, payload, cx)
1424                } else {
1425                    false
1426                }
1427            }),
1428        });
1429        Subscription::Subscription {
1430            id: subscription_id,
1431            entity_id: handle.id(),
1432            subscriptions: Some(Arc::downgrade(&self.subscriptions)),
1433        }
1434    }
1435
1436    fn observe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
1437    where
1438        E: Entity,
1439        E::Event: 'static,
1440        H: Handle<E>,
1441        F: 'static + FnMut(H, &mut Self) -> bool,
1442    {
1443        let subscription_id = post_inc(&mut self.next_subscription_id);
1444        let observed = handle.downgrade();
1445        let entity_id = handle.id();
1446        self.pending_effects.push_back(Effect::Observation {
1447            entity_id,
1448            subscription_id,
1449            callback: Box::new(move |cx| {
1450                if let Some(observed) = H::upgrade_from(&observed, cx) {
1451                    callback(observed, cx)
1452                } else {
1453                    false
1454                }
1455            }),
1456        });
1457        Subscription::Observation {
1458            id: subscription_id,
1459            entity_id,
1460            observations: Some(Arc::downgrade(&self.observations)),
1461        }
1462    }
1463
1464    fn observe_focus<F, V>(&mut self, handle: &ViewHandle<V>, mut callback: F) -> Subscription
1465    where
1466        F: 'static + FnMut(ViewHandle<V>, bool, &mut MutableAppContext) -> bool,
1467        V: View,
1468    {
1469        let subscription_id = post_inc(&mut self.next_subscription_id);
1470        let observed = handle.downgrade();
1471        let view_id = handle.id();
1472        self.pending_effects.push_back(Effect::FocusObservation {
1473            view_id,
1474            subscription_id,
1475            callback: Box::new(move |focused, cx| {
1476                if let Some(observed) = observed.upgrade(cx) {
1477                    callback(observed, focused, cx)
1478                } else {
1479                    false
1480                }
1481            }),
1482        });
1483        Subscription::FocusObservation {
1484            id: subscription_id,
1485            view_id,
1486            observations: Some(Arc::downgrade(&self.focus_observations)),
1487        }
1488    }
1489
1490    pub fn observe_global<G, F>(&mut self, mut observe: F) -> Subscription
1491    where
1492        G: Any,
1493        F: 'static + FnMut(&mut MutableAppContext),
1494    {
1495        let type_id = TypeId::of::<G>();
1496        let id = post_inc(&mut self.next_subscription_id);
1497
1498        self.global_observations
1499            .lock()
1500            .entry(type_id)
1501            .or_default()
1502            .insert(
1503                id,
1504                Some(Box::new(move |cx: &mut MutableAppContext| observe(cx))
1505                    as GlobalObservationCallback),
1506            );
1507
1508        Subscription::GlobalObservation {
1509            id,
1510            type_id,
1511            observations: Some(Arc::downgrade(&self.global_observations)),
1512        }
1513    }
1514
1515    pub fn observe_release<E, H, F>(&mut self, handle: &H, callback: F) -> Subscription
1516    where
1517        E: Entity,
1518        E::Event: 'static,
1519        H: Handle<E>,
1520        F: 'static + FnOnce(&E, &mut Self),
1521    {
1522        let id = post_inc(&mut self.next_subscription_id);
1523        self.release_observations
1524            .lock()
1525            .entry(handle.id())
1526            .or_default()
1527            .insert(
1528                id,
1529                Box::new(move |released, cx| {
1530                    let released = released.downcast_ref().unwrap();
1531                    callback(released, cx)
1532                }),
1533            );
1534        Subscription::ReleaseObservation {
1535            id,
1536            entity_id: handle.id(),
1537            observations: Some(Arc::downgrade(&self.release_observations)),
1538        }
1539    }
1540
1541    pub fn observe_actions<F>(&mut self, callback: F) -> Subscription
1542    where
1543        F: 'static + FnMut(TypeId, &mut MutableAppContext),
1544    {
1545        let id = post_inc(&mut self.next_subscription_id);
1546        self.action_dispatch_observations
1547            .lock()
1548            .insert(id, Box::new(callback));
1549        Subscription::ActionObservation {
1550            id,
1551            observations: Some(Arc::downgrade(&self.action_dispatch_observations)),
1552        }
1553    }
1554
1555    fn observe_window_activation<F>(&mut self, window_id: usize, callback: F) -> Subscription
1556    where
1557        F: 'static + FnMut(bool, &mut MutableAppContext) -> bool,
1558    {
1559        let subscription_id = post_inc(&mut self.next_subscription_id);
1560        self.pending_effects
1561            .push_back(Effect::WindowActivationObservation {
1562                window_id,
1563                subscription_id,
1564                callback: Box::new(callback),
1565            });
1566        Subscription::WindowActivationObservation {
1567            id: subscription_id,
1568            window_id,
1569            observations: Some(Arc::downgrade(&self.window_activation_observations)),
1570        }
1571    }
1572
1573    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut MutableAppContext)) {
1574        self.pending_effects.push_back(Effect::Deferred {
1575            callback: Box::new(callback),
1576            after_window_update: false,
1577        })
1578    }
1579
1580    pub fn after_window_update(&mut self, callback: impl 'static + FnOnce(&mut MutableAppContext)) {
1581        self.pending_effects.push_back(Effect::Deferred {
1582            callback: Box::new(callback),
1583            after_window_update: true,
1584        })
1585    }
1586
1587    pub(crate) fn notify_model(&mut self, model_id: usize) {
1588        if self.pending_notifications.insert(model_id) {
1589            self.pending_effects
1590                .push_back(Effect::ModelNotification { model_id });
1591        }
1592    }
1593
1594    pub(crate) fn notify_view(&mut self, window_id: usize, view_id: usize) {
1595        if self.pending_notifications.insert(view_id) {
1596            self.pending_effects
1597                .push_back(Effect::ViewNotification { window_id, view_id });
1598        }
1599    }
1600
1601    pub(crate) fn notify_global(&mut self, type_id: TypeId) {
1602        if self.pending_global_notifications.insert(type_id) {
1603            self.pending_effects
1604                .push_back(Effect::GlobalNotification { type_id });
1605        }
1606    }
1607
1608    pub fn all_action_names<'a>(&'a self) -> impl Iterator<Item = &'static str> + 'a {
1609        self.action_deserializers.keys().copied()
1610    }
1611
1612    pub fn available_actions(
1613        &self,
1614        window_id: usize,
1615        view_id: usize,
1616    ) -> impl Iterator<Item = (&'static str, Box<dyn Action>, SmallVec<[&Binding; 1]>)> {
1617        let mut action_types: HashSet<_> = self.global_actions.keys().copied().collect();
1618
1619        let presenter = self
1620            .presenters_and_platform_windows
1621            .get(&window_id)
1622            .unwrap()
1623            .0
1624            .clone();
1625        let mut dispatch_path = Vec::new();
1626        presenter
1627            .borrow()
1628            .compute_dispatch_path_from(view_id, &mut dispatch_path);
1629        for view_id in dispatch_path {
1630            if let Some(view) = self.views.get(&(window_id, view_id)) {
1631                let view_type = view.as_any().type_id();
1632                if let Some(actions) = self.actions.get(&view_type) {
1633                    action_types.extend(actions.keys().copied());
1634                }
1635            }
1636        }
1637
1638        self.action_deserializers
1639            .iter()
1640            .filter_map(move |(name, (type_id, deserialize))| {
1641                if action_types.contains(type_id) {
1642                    Some((
1643                        *name,
1644                        deserialize("{}").ok()?,
1645                        self.keystroke_matcher
1646                            .bindings_for_action_type(*type_id)
1647                            .collect(),
1648                    ))
1649                } else {
1650                    None
1651                }
1652            })
1653    }
1654
1655    pub fn is_action_available(&self, action: &dyn Action) -> bool {
1656        let action_type = action.as_any().type_id();
1657        if let Some(window_id) = self.cx.platform.key_window_id() {
1658            if let Some((presenter, _)) = self.presenters_and_platform_windows.get(&window_id) {
1659                let dispatch_path = presenter.borrow().dispatch_path(&self.cx);
1660                for view_id in dispatch_path {
1661                    if let Some(view) = self.views.get(&(window_id, view_id)) {
1662                        let view_type = view.as_any().type_id();
1663                        if let Some(actions) = self.actions.get(&view_type) {
1664                            if actions.contains_key(&action_type) {
1665                                return true;
1666                            }
1667                        }
1668                    }
1669                }
1670            }
1671        }
1672        self.global_actions.contains_key(&action_type)
1673    }
1674
1675    /// Return keystrokes that would dispatch the given action closest to the focused view, if there are any.
1676    pub(crate) fn keystrokes_for_action(
1677        &self,
1678        window_id: usize,
1679        dispatch_path: &[usize],
1680        action: &dyn Action,
1681    ) -> Option<SmallVec<[Keystroke; 2]>> {
1682        for view_id in dispatch_path.iter().rev() {
1683            let view = self
1684                .cx
1685                .views
1686                .get(&(window_id, *view_id))
1687                .expect("view in responder chain does not exist");
1688            let cx = view.keymap_context(self.as_ref());
1689            let keystrokes = self.keystroke_matcher.keystrokes_for_action(action, &cx);
1690            if keystrokes.is_some() {
1691                return keystrokes;
1692            }
1693        }
1694
1695        None
1696    }
1697
1698    pub fn dispatch_action_at(&mut self, window_id: usize, view_id: usize, action: &dyn Action) {
1699        let presenter = self
1700            .presenters_and_platform_windows
1701            .get(&window_id)
1702            .unwrap()
1703            .0
1704            .clone();
1705        let mut dispatch_path = Vec::new();
1706        presenter
1707            .borrow()
1708            .compute_dispatch_path_from(view_id, &mut dispatch_path);
1709        self.dispatch_action_any(window_id, &dispatch_path, action);
1710    }
1711
1712    pub fn dispatch_action<A: Action>(
1713        &mut self,
1714        window_id: usize,
1715        dispatch_path: Vec<usize>,
1716        action: &A,
1717    ) {
1718        self.dispatch_action_any(window_id, &dispatch_path, action);
1719    }
1720
1721    pub(crate) fn dispatch_action_any(
1722        &mut self,
1723        window_id: usize,
1724        path: &[usize],
1725        action: &dyn Action,
1726    ) -> bool {
1727        self.update(|this| {
1728            this.halt_action_dispatch = false;
1729            for (capture_phase, view_id) in path
1730                .iter()
1731                .map(|view_id| (true, *view_id))
1732                .chain(path.iter().rev().map(|view_id| (false, *view_id)))
1733            {
1734                if let Some(mut view) = this.cx.views.remove(&(window_id, view_id)) {
1735                    let type_id = view.as_any().type_id();
1736
1737                    if let Some((name, mut handlers)) = this
1738                        .actions_mut(capture_phase)
1739                        .get_mut(&type_id)
1740                        .and_then(|h| h.remove_entry(&action.id()))
1741                    {
1742                        for handler in handlers.iter_mut().rev() {
1743                            this.halt_action_dispatch = true;
1744                            handler(view.as_mut(), action, this, window_id, view_id);
1745                            if this.halt_action_dispatch {
1746                                break;
1747                            }
1748                        }
1749                        this.actions_mut(capture_phase)
1750                            .get_mut(&type_id)
1751                            .unwrap()
1752                            .insert(name, handlers);
1753                    }
1754
1755                    this.cx.views.insert((window_id, view_id), view);
1756
1757                    if this.halt_action_dispatch {
1758                        break;
1759                    }
1760                }
1761            }
1762
1763            if !this.halt_action_dispatch {
1764                this.halt_action_dispatch = this.dispatch_global_action_any(action);
1765            }
1766
1767            this.pending_effects
1768                .push_back(Effect::ActionDispatchNotification {
1769                    action_id: action.id(),
1770                });
1771            this.halt_action_dispatch
1772        })
1773    }
1774
1775    fn actions_mut(
1776        &mut self,
1777        capture_phase: bool,
1778    ) -> &mut HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>> {
1779        if capture_phase {
1780            &mut self.capture_actions
1781        } else {
1782            &mut self.actions
1783        }
1784    }
1785
1786    pub fn dispatch_global_action<A: Action>(&mut self, action: A) {
1787        self.dispatch_global_action_any(&action);
1788    }
1789
1790    fn dispatch_global_action_any(&mut self, action: &dyn Action) -> bool {
1791        self.update(|this| {
1792            if let Some((name, mut handler)) = this.global_actions.remove_entry(&action.id()) {
1793                handler(action, this);
1794                this.global_actions.insert(name, handler);
1795                true
1796            } else {
1797                false
1798            }
1799        })
1800    }
1801
1802    pub fn add_bindings<T: IntoIterator<Item = keymap::Binding>>(&mut self, bindings: T) {
1803        self.keystroke_matcher.add_bindings(bindings);
1804    }
1805
1806    pub fn clear_bindings(&mut self) {
1807        self.keystroke_matcher.clear_bindings();
1808    }
1809
1810    pub fn dispatch_keystroke(
1811        &mut self,
1812        window_id: usize,
1813        dispatch_path: Vec<usize>,
1814        keystroke: &Keystroke,
1815    ) -> bool {
1816        let mut context_chain = Vec::new();
1817        for view_id in &dispatch_path {
1818            let view = self
1819                .cx
1820                .views
1821                .get(&(window_id, *view_id))
1822                .expect("view in responder chain does not exist");
1823            context_chain.push(view.keymap_context(self.as_ref()));
1824        }
1825
1826        let mut pending = false;
1827        for (i, cx) in context_chain.iter().enumerate().rev() {
1828            match self
1829                .keystroke_matcher
1830                .push_keystroke(keystroke.clone(), dispatch_path[i], cx)
1831            {
1832                MatchResult::None => {}
1833                MatchResult::Pending => pending = true,
1834                MatchResult::Action(action) => {
1835                    if self.dispatch_action_any(window_id, &dispatch_path[0..=i], action.as_ref()) {
1836                        self.keystroke_matcher.clear_pending();
1837                        return true;
1838                    }
1839                }
1840            }
1841        }
1842
1843        pending
1844    }
1845
1846    pub fn default_global<T: 'static + Default>(&mut self) -> &T {
1847        let type_id = TypeId::of::<T>();
1848        self.update(|this| {
1849            if let Entry::Vacant(entry) = this.cx.globals.entry(type_id) {
1850                entry.insert(Box::new(T::default()));
1851                this.notify_global(type_id);
1852            }
1853        });
1854        self.globals.get(&type_id).unwrap().downcast_ref().unwrap()
1855    }
1856
1857    pub fn set_global<T: 'static>(&mut self, state: T) {
1858        self.update(|this| {
1859            let type_id = TypeId::of::<T>();
1860            this.cx.globals.insert(type_id, Box::new(state));
1861            this.notify_global(type_id);
1862        });
1863    }
1864
1865    pub fn update_default_global<T, F, U>(&mut self, update: F) -> U
1866    where
1867        T: 'static + Default,
1868        F: FnOnce(&mut T, &mut MutableAppContext) -> U,
1869    {
1870        self.update(|this| {
1871            let type_id = TypeId::of::<T>();
1872            let mut state = this
1873                .cx
1874                .globals
1875                .remove(&type_id)
1876                .unwrap_or_else(|| Box::new(T::default()));
1877            let result = update(state.downcast_mut().unwrap(), this);
1878            this.cx.globals.insert(type_id, state);
1879            this.notify_global(type_id);
1880            result
1881        })
1882    }
1883
1884    pub fn update_global<T, F, U>(&mut self, update: F) -> U
1885    where
1886        T: 'static,
1887        F: FnOnce(&mut T, &mut MutableAppContext) -> U,
1888    {
1889        self.update(|this| {
1890            let type_id = TypeId::of::<T>();
1891            let mut state = this
1892                .cx
1893                .globals
1894                .remove(&type_id)
1895                .expect("no global has been added for this type");
1896            let result = update(state.downcast_mut().unwrap(), this);
1897            this.cx.globals.insert(type_id, state);
1898            this.notify_global(type_id);
1899            result
1900        })
1901    }
1902
1903    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
1904    where
1905        T: Entity,
1906        F: FnOnce(&mut ModelContext<T>) -> T,
1907    {
1908        self.update(|this| {
1909            let model_id = post_inc(&mut this.next_entity_id);
1910            let handle = ModelHandle::new(model_id, &this.cx.ref_counts);
1911            let mut cx = ModelContext::new(this, model_id);
1912            let model = build_model(&mut cx);
1913            this.cx.models.insert(model_id, Box::new(model));
1914            handle
1915        })
1916    }
1917
1918    pub fn add_window<T, F>(
1919        &mut self,
1920        window_options: WindowOptions,
1921        build_root_view: F,
1922    ) -> (usize, ViewHandle<T>)
1923    where
1924        T: View,
1925        F: FnOnce(&mut ViewContext<T>) -> T,
1926    {
1927        self.update(|this| {
1928            let window_id = post_inc(&mut this.next_window_id);
1929            let root_view = this.add_view(window_id, build_root_view);
1930            this.cx.windows.insert(
1931                window_id,
1932                Window {
1933                    root_view: root_view.clone().into(),
1934                    focused_view_id: Some(root_view.id()),
1935                    is_active: false,
1936                    invalidation: None,
1937                },
1938            );
1939            root_view.update(this, |view, cx| view.on_focus(cx));
1940            this.open_platform_window(window_id, window_options);
1941
1942            (window_id, root_view)
1943        })
1944    }
1945
1946    pub fn replace_root_view<T, F>(&mut self, window_id: usize, build_root_view: F) -> ViewHandle<T>
1947    where
1948        T: View,
1949        F: FnOnce(&mut ViewContext<T>) -> T,
1950    {
1951        self.update(|this| {
1952            let root_view = this.add_view(window_id, build_root_view);
1953            let window = this.cx.windows.get_mut(&window_id).unwrap();
1954            window.root_view = root_view.clone().into();
1955            window.focused_view_id = Some(root_view.id());
1956            root_view
1957        })
1958    }
1959
1960    pub fn remove_window(&mut self, window_id: usize) {
1961        self.cx.windows.remove(&window_id);
1962        self.presenters_and_platform_windows.remove(&window_id);
1963        self.flush_effects();
1964    }
1965
1966    fn open_platform_window(&mut self, window_id: usize, window_options: WindowOptions) {
1967        let mut window =
1968            self.cx
1969                .platform
1970                .open_window(window_id, window_options, self.foreground.clone());
1971        let presenter = Rc::new(RefCell::new(
1972            self.build_presenter(window_id, window.titlebar_height()),
1973        ));
1974
1975        {
1976            let mut app = self.upgrade();
1977            let presenter = Rc::downgrade(&presenter);
1978            window.on_event(Box::new(move |event| {
1979                app.update(|cx| {
1980                    if let Some(presenter) = presenter.upgrade() {
1981                        if let Event::KeyDown(KeyDownEvent { keystroke, .. }) = &event {
1982                            if cx.dispatch_keystroke(
1983                                window_id,
1984                                presenter.borrow().dispatch_path(cx.as_ref()),
1985                                keystroke,
1986                            ) {
1987                                return true;
1988                            }
1989                        }
1990
1991                        presenter.borrow_mut().dispatch_event(event, cx)
1992                    } else {
1993                        false
1994                    }
1995                })
1996            }));
1997        }
1998
1999        {
2000            let mut app = self.upgrade();
2001            window.on_active_status_change(Box::new(move |is_active| {
2002                app.update(|cx| cx.window_changed_active_status(window_id, is_active))
2003            }));
2004        }
2005
2006        {
2007            let mut app = self.upgrade();
2008            window.on_resize(Box::new(move || {
2009                app.update(|cx| cx.window_was_resized(window_id))
2010            }));
2011        }
2012
2013        {
2014            let mut app = self.upgrade();
2015            window.on_close(Box::new(move || {
2016                app.update(|cx| cx.remove_window(window_id));
2017            }));
2018        }
2019
2020        window.set_input_handler(Box::new(WindowInputHandler {
2021            app: self.upgrade().0,
2022            window_id,
2023        }));
2024
2025        let scene =
2026            presenter
2027                .borrow_mut()
2028                .build_scene(window.size(), window.scale_factor(), false, self);
2029        window.present_scene(scene);
2030        self.presenters_and_platform_windows
2031            .insert(window_id, (presenter.clone(), window));
2032    }
2033
2034    pub fn build_presenter(&mut self, window_id: usize, titlebar_height: f32) -> Presenter {
2035        Presenter::new(
2036            window_id,
2037            titlebar_height,
2038            self.cx.font_cache.clone(),
2039            TextLayoutCache::new(self.cx.platform.fonts()),
2040            self.assets.clone(),
2041            self,
2042        )
2043    }
2044
2045    pub fn add_view<T, F>(&mut self, window_id: usize, build_view: F) -> ViewHandle<T>
2046    where
2047        T: View,
2048        F: FnOnce(&mut ViewContext<T>) -> T,
2049    {
2050        self.add_option_view(window_id, |cx| Some(build_view(cx)))
2051            .unwrap()
2052    }
2053
2054    pub fn add_option_view<T, F>(
2055        &mut self,
2056        window_id: usize,
2057        build_view: F,
2058    ) -> Option<ViewHandle<T>>
2059    where
2060        T: View,
2061        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
2062    {
2063        self.update(|this| {
2064            let view_id = post_inc(&mut this.next_entity_id);
2065            let mut cx = ViewContext::new(this, window_id, view_id);
2066            let handle = if let Some(view) = build_view(&mut cx) {
2067                this.cx.views.insert((window_id, view_id), Box::new(view));
2068                if let Some(window) = this.cx.windows.get_mut(&window_id) {
2069                    window
2070                        .invalidation
2071                        .get_or_insert_with(Default::default)
2072                        .updated
2073                        .insert(view_id);
2074                }
2075                Some(ViewHandle::new(window_id, view_id, &this.cx.ref_counts))
2076            } else {
2077                None
2078            };
2079            handle
2080        })
2081    }
2082
2083    fn remove_dropped_entities(&mut self) {
2084        loop {
2085            let (dropped_models, dropped_views, dropped_element_states) =
2086                self.cx.ref_counts.lock().take_dropped();
2087            if dropped_models.is_empty()
2088                && dropped_views.is_empty()
2089                && dropped_element_states.is_empty()
2090            {
2091                break;
2092            }
2093
2094            for model_id in dropped_models {
2095                self.subscriptions.lock().remove(&model_id);
2096                self.observations.lock().remove(&model_id);
2097                let mut model = self.cx.models.remove(&model_id).unwrap();
2098                model.release(self);
2099                self.pending_effects
2100                    .push_back(Effect::ModelRelease { model_id, model });
2101            }
2102
2103            for (window_id, view_id) in dropped_views {
2104                self.subscriptions.lock().remove(&view_id);
2105                self.observations.lock().remove(&view_id);
2106                let mut view = self.cx.views.remove(&(window_id, view_id)).unwrap();
2107                view.release(self);
2108                let change_focus_to = self.cx.windows.get_mut(&window_id).and_then(|window| {
2109                    window
2110                        .invalidation
2111                        .get_or_insert_with(Default::default)
2112                        .removed
2113                        .push(view_id);
2114                    if window.focused_view_id == Some(view_id) {
2115                        Some(window.root_view.id())
2116                    } else {
2117                        None
2118                    }
2119                });
2120
2121                if let Some(view_id) = change_focus_to {
2122                    self.handle_focus_effect(window_id, Some(view_id));
2123                }
2124
2125                self.pending_effects
2126                    .push_back(Effect::ViewRelease { view_id, view });
2127            }
2128
2129            for key in dropped_element_states {
2130                self.cx.element_states.remove(&key);
2131            }
2132        }
2133    }
2134
2135    fn flush_effects(&mut self) {
2136        self.pending_flushes = self.pending_flushes.saturating_sub(1);
2137        let mut after_window_update_callbacks = Vec::new();
2138
2139        if !self.flushing_effects && self.pending_flushes == 0 {
2140            self.flushing_effects = true;
2141
2142            let mut refreshing = false;
2143            loop {
2144                if let Some(effect) = self.pending_effects.pop_front() {
2145                    if let Some(pending_focus_index) = self.pending_focus_index.as_mut() {
2146                        *pending_focus_index = pending_focus_index.saturating_sub(1);
2147                    }
2148                    match effect {
2149                        Effect::Subscription {
2150                            entity_id,
2151                            subscription_id,
2152                            callback,
2153                        } => self.handle_subscription_effect(entity_id, subscription_id, callback),
2154                        Effect::Event { entity_id, payload } => self.emit_event(entity_id, payload),
2155                        Effect::GlobalSubscription {
2156                            type_id,
2157                            subscription_id,
2158                            callback,
2159                        } => self.handle_global_subscription_effect(
2160                            type_id,
2161                            subscription_id,
2162                            callback,
2163                        ),
2164                        Effect::GlobalEvent { payload } => self.emit_global_event(payload),
2165                        Effect::Observation {
2166                            entity_id,
2167                            subscription_id,
2168                            callback,
2169                        } => self.handle_observation_effect(entity_id, subscription_id, callback),
2170                        Effect::ModelNotification { model_id } => {
2171                            self.handle_model_notification_effect(model_id)
2172                        }
2173                        Effect::ViewNotification { window_id, view_id } => {
2174                            self.handle_view_notification_effect(window_id, view_id)
2175                        }
2176                        Effect::GlobalNotification { type_id } => {
2177                            self.handle_global_notification_effect(type_id)
2178                        }
2179                        Effect::Deferred {
2180                            callback,
2181                            after_window_update,
2182                        } => {
2183                            if after_window_update {
2184                                after_window_update_callbacks.push(callback);
2185                            } else {
2186                                callback(self)
2187                            }
2188                        }
2189                        Effect::ModelRelease { model_id, model } => {
2190                            self.handle_entity_release_effect(model_id, model.as_any())
2191                        }
2192                        Effect::ViewRelease { view_id, view } => {
2193                            self.handle_entity_release_effect(view_id, view.as_any())
2194                        }
2195                        Effect::Focus { window_id, view_id } => {
2196                            self.handle_focus_effect(window_id, view_id);
2197                        }
2198                        Effect::FocusObservation {
2199                            view_id,
2200                            subscription_id,
2201                            callback,
2202                        } => {
2203                            self.handle_focus_observation_effect(view_id, subscription_id, callback)
2204                        }
2205                        Effect::ResizeWindow { window_id } => {
2206                            if let Some(window) = self.cx.windows.get_mut(&window_id) {
2207                                window
2208                                    .invalidation
2209                                    .get_or_insert(WindowInvalidation::default());
2210                            }
2211                        }
2212                        Effect::WindowActivationObservation {
2213                            window_id,
2214                            subscription_id,
2215                            callback,
2216                        } => self.handle_window_activation_observation_effect(
2217                            window_id,
2218                            subscription_id,
2219                            callback,
2220                        ),
2221                        Effect::ActivateWindow {
2222                            window_id,
2223                            is_active,
2224                        } => self.handle_window_activation_effect(window_id, is_active),
2225                        Effect::RefreshWindows => {
2226                            refreshing = true;
2227                        }
2228                        Effect::ActionDispatchNotification { action_id } => {
2229                            self.handle_action_dispatch_notification_effect(action_id)
2230                        }
2231                        Effect::WindowShouldCloseSubscription {
2232                            window_id,
2233                            callback,
2234                        } => {
2235                            self.handle_window_should_close_subscription_effect(window_id, callback)
2236                        }
2237                    }
2238                    self.pending_notifications.clear();
2239                    self.remove_dropped_entities();
2240                } else {
2241                    self.remove_dropped_entities();
2242                    if refreshing {
2243                        self.perform_window_refresh();
2244                    } else {
2245                        self.update_windows();
2246                    }
2247
2248                    if self.pending_effects.is_empty() {
2249                        for callback in after_window_update_callbacks.drain(..) {
2250                            callback(self);
2251                        }
2252
2253                        if self.pending_effects.is_empty() {
2254                            self.flushing_effects = false;
2255                            self.pending_notifications.clear();
2256                            self.pending_global_notifications.clear();
2257                            break;
2258                        }
2259                    }
2260
2261                    refreshing = false;
2262                }
2263            }
2264        }
2265    }
2266
2267    fn update_windows(&mut self) {
2268        let mut invalidations = HashMap::new();
2269        for (window_id, window) in &mut self.cx.windows {
2270            if let Some(invalidation) = window.invalidation.take() {
2271                invalidations.insert(*window_id, invalidation);
2272            }
2273        }
2274
2275        for (window_id, mut invalidation) in invalidations {
2276            if let Some((presenter, mut window)) =
2277                self.presenters_and_platform_windows.remove(&window_id)
2278            {
2279                {
2280                    let mut presenter = presenter.borrow_mut();
2281                    presenter.invalidate(&mut invalidation, self);
2282                    let scene =
2283                        presenter.build_scene(window.size(), window.scale_factor(), false, self);
2284                    window.present_scene(scene);
2285                }
2286                self.presenters_and_platform_windows
2287                    .insert(window_id, (presenter, window));
2288            }
2289        }
2290    }
2291
2292    fn window_was_resized(&mut self, window_id: usize) {
2293        self.pending_effects
2294            .push_back(Effect::ResizeWindow { window_id });
2295    }
2296
2297    fn window_changed_active_status(&mut self, window_id: usize, is_active: bool) {
2298        self.pending_effects.push_back(Effect::ActivateWindow {
2299            window_id,
2300            is_active,
2301        });
2302    }
2303
2304    pub fn refresh_windows(&mut self) {
2305        self.pending_effects.push_back(Effect::RefreshWindows);
2306    }
2307
2308    fn perform_window_refresh(&mut self) {
2309        let mut presenters = mem::take(&mut self.presenters_and_platform_windows);
2310        for (window_id, (presenter, window)) in &mut presenters {
2311            let mut invalidation = self
2312                .cx
2313                .windows
2314                .get_mut(&window_id)
2315                .unwrap()
2316                .invalidation
2317                .take();
2318            let mut presenter = presenter.borrow_mut();
2319            presenter.refresh(
2320                invalidation.as_mut().unwrap_or(&mut Default::default()),
2321                self,
2322            );
2323            let scene = presenter.build_scene(window.size(), window.scale_factor(), true, self);
2324            window.present_scene(scene);
2325        }
2326        self.presenters_and_platform_windows = presenters;
2327    }
2328
2329    fn handle_subscription_effect(
2330        &mut self,
2331        entity_id: usize,
2332        subscription_id: usize,
2333        callback: SubscriptionCallback,
2334    ) {
2335        match self
2336            .subscriptions
2337            .lock()
2338            .entry(entity_id)
2339            .or_default()
2340            .entry(subscription_id)
2341        {
2342            btree_map::Entry::Vacant(entry) => {
2343                entry.insert(Some(callback));
2344            }
2345            // Subscription was dropped before effect was processed
2346            btree_map::Entry::Occupied(entry) => {
2347                debug_assert!(entry.get().is_none());
2348                entry.remove();
2349            }
2350        }
2351    }
2352
2353    fn emit_event(&mut self, entity_id: usize, payload: Box<dyn Any>) {
2354        let callbacks = self.subscriptions.lock().remove(&entity_id);
2355        if let Some(callbacks) = callbacks {
2356            for (id, callback) in callbacks {
2357                if let Some(mut callback) = callback {
2358                    let alive = callback(payload.as_ref(), self);
2359                    if alive {
2360                        match self
2361                            .subscriptions
2362                            .lock()
2363                            .entry(entity_id)
2364                            .or_default()
2365                            .entry(id)
2366                        {
2367                            btree_map::Entry::Vacant(entry) => {
2368                                entry.insert(Some(callback));
2369                            }
2370                            btree_map::Entry::Occupied(entry) => {
2371                                entry.remove();
2372                            }
2373                        }
2374                    }
2375                }
2376            }
2377        }
2378    }
2379
2380    fn handle_global_subscription_effect(
2381        &mut self,
2382        type_id: TypeId,
2383        subscription_id: usize,
2384        callback: GlobalSubscriptionCallback,
2385    ) {
2386        match self
2387            .global_subscriptions
2388            .lock()
2389            .entry(type_id)
2390            .or_default()
2391            .entry(subscription_id)
2392        {
2393            btree_map::Entry::Vacant(entry) => {
2394                entry.insert(Some(callback));
2395            }
2396            // Subscription was dropped before effect was processed
2397            btree_map::Entry::Occupied(entry) => {
2398                debug_assert!(entry.get().is_none());
2399                entry.remove();
2400            }
2401        }
2402    }
2403
2404    fn emit_global_event(&mut self, payload: Box<dyn Any>) {
2405        let type_id = (&*payload).type_id();
2406        let callbacks = self.global_subscriptions.lock().remove(&type_id);
2407        if let Some(callbacks) = callbacks {
2408            for (id, callback) in callbacks {
2409                if let Some(mut callback) = callback {
2410                    callback(payload.as_ref(), self);
2411                    match self
2412                        .global_subscriptions
2413                        .lock()
2414                        .entry(type_id)
2415                        .or_default()
2416                        .entry(id)
2417                    {
2418                        btree_map::Entry::Vacant(entry) => {
2419                            entry.insert(Some(callback));
2420                        }
2421                        btree_map::Entry::Occupied(entry) => {
2422                            entry.remove();
2423                        }
2424                    }
2425                }
2426            }
2427        }
2428    }
2429
2430    fn handle_observation_effect(
2431        &mut self,
2432        entity_id: usize,
2433        subscription_id: usize,
2434        callback: ObservationCallback,
2435    ) {
2436        match self
2437            .observations
2438            .lock()
2439            .entry(entity_id)
2440            .or_default()
2441            .entry(subscription_id)
2442        {
2443            btree_map::Entry::Vacant(entry) => {
2444                entry.insert(Some(callback));
2445            }
2446            // Observation was dropped before effect was processed
2447            btree_map::Entry::Occupied(entry) => {
2448                debug_assert!(entry.get().is_none());
2449                entry.remove();
2450            }
2451        }
2452    }
2453
2454    fn handle_focus_observation_effect(
2455        &mut self,
2456        view_id: usize,
2457        subscription_id: usize,
2458        callback: FocusObservationCallback,
2459    ) {
2460        match self
2461            .focus_observations
2462            .lock()
2463            .entry(view_id)
2464            .or_default()
2465            .entry(subscription_id)
2466        {
2467            btree_map::Entry::Vacant(entry) => {
2468                entry.insert(Some(callback));
2469            }
2470            // Observation was dropped before effect was processed
2471            btree_map::Entry::Occupied(entry) => {
2472                debug_assert!(entry.get().is_none());
2473                entry.remove();
2474            }
2475        }
2476    }
2477
2478    fn handle_model_notification_effect(&mut self, observed_id: usize) {
2479        let callbacks = self.observations.lock().remove(&observed_id);
2480        if let Some(callbacks) = callbacks {
2481            if self.cx.models.contains_key(&observed_id) {
2482                for (id, callback) in callbacks {
2483                    if let Some(mut callback) = callback {
2484                        let alive = callback(self);
2485                        if alive {
2486                            match self
2487                                .observations
2488                                .lock()
2489                                .entry(observed_id)
2490                                .or_default()
2491                                .entry(id)
2492                            {
2493                                btree_map::Entry::Vacant(entry) => {
2494                                    entry.insert(Some(callback));
2495                                }
2496                                btree_map::Entry::Occupied(entry) => {
2497                                    entry.remove();
2498                                }
2499                            }
2500                        }
2501                    }
2502                }
2503            }
2504        }
2505    }
2506
2507    fn handle_view_notification_effect(
2508        &mut self,
2509        observed_window_id: usize,
2510        observed_view_id: usize,
2511    ) {
2512        let callbacks = self.observations.lock().remove(&observed_view_id);
2513
2514        if self
2515            .cx
2516            .views
2517            .contains_key(&(observed_window_id, observed_view_id))
2518        {
2519            if let Some(window) = self.cx.windows.get_mut(&observed_window_id) {
2520                window
2521                    .invalidation
2522                    .get_or_insert_with(Default::default)
2523                    .updated
2524                    .insert(observed_view_id);
2525            }
2526
2527            if let Some(callbacks) = callbacks {
2528                for (id, callback) in callbacks {
2529                    if let Some(mut callback) = callback {
2530                        let alive = callback(self);
2531                        if alive {
2532                            match self
2533                                .observations
2534                                .lock()
2535                                .entry(observed_view_id)
2536                                .or_default()
2537                                .entry(id)
2538                            {
2539                                btree_map::Entry::Vacant(entry) => {
2540                                    entry.insert(Some(callback));
2541                                }
2542                                btree_map::Entry::Occupied(entry) => {
2543                                    entry.remove();
2544                                }
2545                            }
2546                        }
2547                    }
2548                }
2549            }
2550        }
2551    }
2552
2553    fn handle_global_notification_effect(&mut self, observed_type_id: TypeId) {
2554        let callbacks = self.global_observations.lock().remove(&observed_type_id);
2555        if let Some(callbacks) = callbacks {
2556            for (id, callback) in callbacks {
2557                if let Some(mut callback) = callback {
2558                    callback(self);
2559                    match self
2560                        .global_observations
2561                        .lock()
2562                        .entry(observed_type_id)
2563                        .or_default()
2564                        .entry(id)
2565                    {
2566                        collections::btree_map::Entry::Vacant(entry) => {
2567                            entry.insert(Some(callback));
2568                        }
2569                        collections::btree_map::Entry::Occupied(entry) => {
2570                            entry.remove();
2571                        }
2572                    }
2573                }
2574            }
2575        }
2576    }
2577
2578    fn handle_entity_release_effect(&mut self, entity_id: usize, entity: &dyn Any) {
2579        let callbacks = self.release_observations.lock().remove(&entity_id);
2580        if let Some(callbacks) = callbacks {
2581            for (_, callback) in callbacks {
2582                callback(entity, self);
2583            }
2584        }
2585    }
2586
2587    fn handle_window_activation_observation_effect(
2588        &mut self,
2589        window_id: usize,
2590        subscription_id: usize,
2591        callback: WindowActivationCallback,
2592    ) {
2593        match self
2594            .window_activation_observations
2595            .lock()
2596            .entry(window_id)
2597            .or_default()
2598            .entry(subscription_id)
2599        {
2600            btree_map::Entry::Vacant(entry) => {
2601                entry.insert(Some(callback));
2602            }
2603            // Observation was dropped before effect was processed
2604            btree_map::Entry::Occupied(entry) => {
2605                debug_assert!(entry.get().is_none());
2606                entry.remove();
2607            }
2608        }
2609    }
2610
2611    fn handle_window_activation_effect(&mut self, window_id: usize, active: bool) {
2612        if self
2613            .cx
2614            .windows
2615            .get(&window_id)
2616            .map(|w| w.is_active)
2617            .map_or(false, |cur_active| cur_active == active)
2618        {
2619            return;
2620        }
2621
2622        self.update(|this| {
2623            let window = this.cx.windows.get_mut(&window_id)?;
2624            window.is_active = active;
2625            let view_id = window.focused_view_id?;
2626            if let Some(mut view) = this.cx.views.remove(&(window_id, view_id)) {
2627                if active {
2628                    view.on_focus(this, window_id, view_id);
2629                } else {
2630                    view.on_blur(this, window_id, view_id);
2631                }
2632                this.cx.views.insert((window_id, view_id), view);
2633            }
2634
2635            let callbacks = this
2636                .window_activation_observations
2637                .lock()
2638                .remove(&window_id);
2639            if let Some(callbacks) = callbacks {
2640                for (id, callback) in callbacks {
2641                    if let Some(mut callback) = callback {
2642                        let alive = callback(active, this);
2643                        if alive {
2644                            match this
2645                                .window_activation_observations
2646                                .lock()
2647                                .entry(window_id)
2648                                .or_default()
2649                                .entry(id)
2650                            {
2651                                btree_map::Entry::Vacant(entry) => {
2652                                    entry.insert(Some(callback));
2653                                }
2654                                btree_map::Entry::Occupied(entry) => {
2655                                    entry.remove();
2656                                }
2657                            }
2658                        }
2659                    }
2660                }
2661            }
2662
2663            Some(())
2664        });
2665    }
2666
2667    fn handle_focus_effect(&mut self, window_id: usize, focused_id: Option<usize>) {
2668        self.pending_focus_index.take();
2669
2670        if self
2671            .cx
2672            .windows
2673            .get(&window_id)
2674            .map(|w| w.focused_view_id)
2675            .map_or(false, |cur_focused| cur_focused == focused_id)
2676        {
2677            return;
2678        }
2679
2680        self.update(|this| {
2681            let blurred_id = this.cx.windows.get_mut(&window_id).and_then(|window| {
2682                let blurred_id = window.focused_view_id;
2683                window.focused_view_id = focused_id;
2684                blurred_id
2685            });
2686
2687            if let Some(blurred_id) = blurred_id {
2688                if let Some(mut blurred_view) = this.cx.views.remove(&(window_id, blurred_id)) {
2689                    blurred_view.on_blur(this, window_id, blurred_id);
2690                    this.cx.views.insert((window_id, blurred_id), blurred_view);
2691
2692                    let callbacks = this.focus_observations.lock().remove(&blurred_id);
2693                    if let Some(callbacks) = callbacks {
2694                        for (id, callback) in callbacks {
2695                            if let Some(mut callback) = callback {
2696                                let alive = callback(false, this);
2697                                if alive {
2698                                    match this
2699                                        .focus_observations
2700                                        .lock()
2701                                        .entry(blurred_id)
2702                                        .or_default()
2703                                        .entry(id)
2704                                    {
2705                                        btree_map::Entry::Vacant(entry) => {
2706                                            entry.insert(Some(callback));
2707                                        }
2708                                        btree_map::Entry::Occupied(entry) => {
2709                                            entry.remove();
2710                                        }
2711                                    }
2712                                }
2713                            }
2714                        }
2715                    }
2716                }
2717            }
2718
2719            if let Some(focused_id) = focused_id {
2720                if let Some(mut focused_view) = this.cx.views.remove(&(window_id, focused_id)) {
2721                    focused_view.on_focus(this, window_id, focused_id);
2722                    this.cx.views.insert((window_id, focused_id), focused_view);
2723
2724                    let callbacks = this.focus_observations.lock().remove(&focused_id);
2725                    if let Some(callbacks) = callbacks {
2726                        for (id, callback) in callbacks {
2727                            if let Some(mut callback) = callback {
2728                                let alive = callback(true, this);
2729                                if alive {
2730                                    match this
2731                                        .focus_observations
2732                                        .lock()
2733                                        .entry(focused_id)
2734                                        .or_default()
2735                                        .entry(id)
2736                                    {
2737                                        btree_map::Entry::Vacant(entry) => {
2738                                            entry.insert(Some(callback));
2739                                        }
2740                                        btree_map::Entry::Occupied(entry) => {
2741                                            entry.remove();
2742                                        }
2743                                    }
2744                                }
2745                            }
2746                        }
2747                    }
2748                }
2749            }
2750        })
2751    }
2752
2753    fn handle_action_dispatch_notification_effect(&mut self, action_id: TypeId) {
2754        let mut callbacks = mem::take(&mut *self.action_dispatch_observations.lock());
2755        for (_, callback) in &mut callbacks {
2756            callback(action_id, self);
2757        }
2758        self.action_dispatch_observations.lock().extend(callbacks);
2759    }
2760
2761    fn handle_window_should_close_subscription_effect(
2762        &mut self,
2763        window_id: usize,
2764        mut callback: WindowShouldCloseSubscriptionCallback,
2765    ) {
2766        let mut app = self.upgrade();
2767        if let Some((_, window)) = self.presenters_and_platform_windows.get_mut(&window_id) {
2768            window.on_should_close(Box::new(move || app.update(|cx| callback(cx))))
2769        }
2770    }
2771
2772    pub fn focus(&mut self, window_id: usize, view_id: Option<usize>) {
2773        if let Some(pending_focus_index) = self.pending_focus_index {
2774            self.pending_effects.remove(pending_focus_index);
2775        }
2776        self.pending_focus_index = Some(self.pending_effects.len());
2777        self.pending_effects
2778            .push_back(Effect::Focus { window_id, view_id });
2779    }
2780
2781    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
2782    where
2783        F: FnOnce(AsyncAppContext) -> Fut,
2784        Fut: 'static + Future<Output = T>,
2785        T: 'static,
2786    {
2787        let future = f(self.to_async());
2788        let cx = self.to_async();
2789        self.foreground.spawn(async move {
2790            let result = future.await;
2791            cx.0.borrow_mut().flush_effects();
2792            result
2793        })
2794    }
2795
2796    pub fn to_async(&self) -> AsyncAppContext {
2797        AsyncAppContext(self.weak_self.as_ref().unwrap().upgrade().unwrap())
2798    }
2799
2800    pub fn write_to_clipboard(&self, item: ClipboardItem) {
2801        self.cx.platform.write_to_clipboard(item);
2802    }
2803
2804    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
2805        self.cx.platform.read_from_clipboard()
2806    }
2807
2808    #[cfg(any(test, feature = "test-support"))]
2809    pub fn leak_detector(&self) -> Arc<Mutex<LeakDetector>> {
2810        self.cx.ref_counts.lock().leak_detector.clone()
2811    }
2812}
2813
2814impl ReadModel for MutableAppContext {
2815    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
2816        if let Some(model) = self.cx.models.get(&handle.model_id) {
2817            model
2818                .as_any()
2819                .downcast_ref()
2820                .expect("downcast is type safe")
2821        } else {
2822            panic!("circular model reference");
2823        }
2824    }
2825}
2826
2827impl UpdateModel for MutableAppContext {
2828    fn update_model<T: Entity, V>(
2829        &mut self,
2830        handle: &ModelHandle<T>,
2831        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> V,
2832    ) -> V {
2833        if let Some(mut model) = self.cx.models.remove(&handle.model_id) {
2834            self.update(|this| {
2835                let mut cx = ModelContext::new(this, handle.model_id);
2836                let result = update(
2837                    model
2838                        .as_any_mut()
2839                        .downcast_mut()
2840                        .expect("downcast is type safe"),
2841                    &mut cx,
2842                );
2843                this.cx.models.insert(handle.model_id, model);
2844                result
2845            })
2846        } else {
2847            panic!("circular model update");
2848        }
2849    }
2850}
2851
2852impl UpgradeModelHandle for MutableAppContext {
2853    fn upgrade_model_handle<T: Entity>(
2854        &self,
2855        handle: &WeakModelHandle<T>,
2856    ) -> Option<ModelHandle<T>> {
2857        self.cx.upgrade_model_handle(handle)
2858    }
2859
2860    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
2861        self.cx.model_handle_is_upgradable(handle)
2862    }
2863
2864    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
2865        self.cx.upgrade_any_model_handle(handle)
2866    }
2867}
2868
2869impl UpgradeViewHandle for MutableAppContext {
2870    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
2871        self.cx.upgrade_view_handle(handle)
2872    }
2873
2874    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
2875        self.cx.upgrade_any_view_handle(handle)
2876    }
2877}
2878
2879impl ReadView for MutableAppContext {
2880    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
2881        if let Some(view) = self.cx.views.get(&(handle.window_id, handle.view_id)) {
2882            view.as_any().downcast_ref().expect("downcast is type safe")
2883        } else {
2884            panic!("circular view reference");
2885        }
2886    }
2887}
2888
2889impl UpdateView for MutableAppContext {
2890    fn update_view<T, S>(
2891        &mut self,
2892        handle: &ViewHandle<T>,
2893        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
2894    ) -> S
2895    where
2896        T: View,
2897    {
2898        self.update(|this| {
2899            let mut view = this
2900                .cx
2901                .views
2902                .remove(&(handle.window_id, handle.view_id))
2903                .expect("circular view update");
2904
2905            let mut cx = ViewContext::new(this, handle.window_id, handle.view_id);
2906            let result = update(
2907                view.as_any_mut()
2908                    .downcast_mut()
2909                    .expect("downcast is type safe"),
2910                &mut cx,
2911            );
2912            this.cx
2913                .views
2914                .insert((handle.window_id, handle.view_id), view);
2915            result
2916        })
2917    }
2918}
2919
2920impl AsRef<AppContext> for MutableAppContext {
2921    fn as_ref(&self) -> &AppContext {
2922        &self.cx
2923    }
2924}
2925
2926impl Deref for MutableAppContext {
2927    type Target = AppContext;
2928
2929    fn deref(&self) -> &Self::Target {
2930        &self.cx
2931    }
2932}
2933
2934pub struct AppContext {
2935    models: HashMap<usize, Box<dyn AnyModel>>,
2936    views: HashMap<(usize, usize), Box<dyn AnyView>>,
2937    windows: HashMap<usize, Window>,
2938    globals: HashMap<TypeId, Box<dyn Any>>,
2939    element_states: HashMap<ElementStateId, Box<dyn Any>>,
2940    background: Arc<executor::Background>,
2941    ref_counts: Arc<Mutex<RefCounts>>,
2942    font_cache: Arc<FontCache>,
2943    platform: Arc<dyn Platform>,
2944}
2945
2946impl AppContext {
2947    pub(crate) fn root_view(&self, window_id: usize) -> Option<AnyViewHandle> {
2948        self.windows
2949            .get(&window_id)
2950            .map(|window| window.root_view.clone())
2951    }
2952
2953    pub fn root_view_id(&self, window_id: usize) -> Option<usize> {
2954        self.windows
2955            .get(&window_id)
2956            .map(|window| window.root_view.id())
2957    }
2958
2959    pub fn focused_view_id(&self, window_id: usize) -> Option<usize> {
2960        self.windows
2961            .get(&window_id)
2962            .and_then(|window| window.focused_view_id)
2963    }
2964
2965    pub fn background(&self) -> &Arc<executor::Background> {
2966        &self.background
2967    }
2968
2969    pub fn font_cache(&self) -> &Arc<FontCache> {
2970        &self.font_cache
2971    }
2972
2973    pub fn platform(&self) -> &Arc<dyn Platform> {
2974        &self.platform
2975    }
2976
2977    pub fn has_global<T: 'static>(&self) -> bool {
2978        self.globals.contains_key(&TypeId::of::<T>())
2979    }
2980
2981    pub fn global<T: 'static>(&self) -> &T {
2982        if let Some(global) = self.globals.get(&TypeId::of::<T>()) {
2983            global.downcast_ref().unwrap()
2984        } else {
2985            panic!("no global has been added for {}", type_name::<T>());
2986        }
2987    }
2988}
2989
2990impl ReadModel for AppContext {
2991    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
2992        if let Some(model) = self.models.get(&handle.model_id) {
2993            model
2994                .as_any()
2995                .downcast_ref()
2996                .expect("downcast should be type safe")
2997        } else {
2998            panic!("circular model reference");
2999        }
3000    }
3001}
3002
3003impl UpgradeModelHandle for AppContext {
3004    fn upgrade_model_handle<T: Entity>(
3005        &self,
3006        handle: &WeakModelHandle<T>,
3007    ) -> Option<ModelHandle<T>> {
3008        if self.models.contains_key(&handle.model_id) {
3009            Some(ModelHandle::new(handle.model_id, &self.ref_counts))
3010        } else {
3011            None
3012        }
3013    }
3014
3015    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
3016        self.models.contains_key(&handle.model_id)
3017    }
3018
3019    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
3020        if self.models.contains_key(&handle.model_id) {
3021            Some(AnyModelHandle::new(
3022                handle.model_id,
3023                handle.model_type,
3024                self.ref_counts.clone(),
3025            ))
3026        } else {
3027            None
3028        }
3029    }
3030}
3031
3032impl UpgradeViewHandle for AppContext {
3033    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
3034        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
3035            Some(ViewHandle::new(
3036                handle.window_id,
3037                handle.view_id,
3038                &self.ref_counts,
3039            ))
3040        } else {
3041            None
3042        }
3043    }
3044
3045    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
3046        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
3047            Some(AnyViewHandle::new(
3048                handle.window_id,
3049                handle.view_id,
3050                handle.view_type,
3051                self.ref_counts.clone(),
3052            ))
3053        } else {
3054            None
3055        }
3056    }
3057}
3058
3059impl ReadView for AppContext {
3060    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
3061        if let Some(view) = self.views.get(&(handle.window_id, handle.view_id)) {
3062            view.as_any()
3063                .downcast_ref()
3064                .expect("downcast should be type safe")
3065        } else {
3066            panic!("circular view reference");
3067        }
3068    }
3069}
3070
3071struct Window {
3072    root_view: AnyViewHandle,
3073    focused_view_id: Option<usize>,
3074    is_active: bool,
3075    invalidation: Option<WindowInvalidation>,
3076}
3077
3078#[derive(Default, Clone)]
3079pub struct WindowInvalidation {
3080    pub updated: HashSet<usize>,
3081    pub removed: Vec<usize>,
3082}
3083
3084pub enum Effect {
3085    Subscription {
3086        entity_id: usize,
3087        subscription_id: usize,
3088        callback: SubscriptionCallback,
3089    },
3090    Event {
3091        entity_id: usize,
3092        payload: Box<dyn Any>,
3093    },
3094    GlobalSubscription {
3095        type_id: TypeId,
3096        subscription_id: usize,
3097        callback: GlobalSubscriptionCallback,
3098    },
3099    GlobalEvent {
3100        payload: Box<dyn Any>,
3101    },
3102    Observation {
3103        entity_id: usize,
3104        subscription_id: usize,
3105        callback: ObservationCallback,
3106    },
3107    ModelNotification {
3108        model_id: usize,
3109    },
3110    ViewNotification {
3111        window_id: usize,
3112        view_id: usize,
3113    },
3114    Deferred {
3115        callback: Box<dyn FnOnce(&mut MutableAppContext)>,
3116        after_window_update: bool,
3117    },
3118    GlobalNotification {
3119        type_id: TypeId,
3120    },
3121    ModelRelease {
3122        model_id: usize,
3123        model: Box<dyn AnyModel>,
3124    },
3125    ViewRelease {
3126        view_id: usize,
3127        view: Box<dyn AnyView>,
3128    },
3129    Focus {
3130        window_id: usize,
3131        view_id: Option<usize>,
3132    },
3133    FocusObservation {
3134        view_id: usize,
3135        subscription_id: usize,
3136        callback: FocusObservationCallback,
3137    },
3138    ResizeWindow {
3139        window_id: usize,
3140    },
3141    ActivateWindow {
3142        window_id: usize,
3143        is_active: bool,
3144    },
3145    WindowActivationObservation {
3146        window_id: usize,
3147        subscription_id: usize,
3148        callback: WindowActivationCallback,
3149    },
3150    RefreshWindows,
3151    ActionDispatchNotification {
3152        action_id: TypeId,
3153    },
3154    WindowShouldCloseSubscription {
3155        window_id: usize,
3156        callback: WindowShouldCloseSubscriptionCallback,
3157    },
3158}
3159
3160impl Debug for Effect {
3161    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3162        match self {
3163            Effect::Subscription {
3164                entity_id,
3165                subscription_id,
3166                ..
3167            } => f
3168                .debug_struct("Effect::Subscribe")
3169                .field("entity_id", entity_id)
3170                .field("subscription_id", subscription_id)
3171                .finish(),
3172            Effect::Event { entity_id, .. } => f
3173                .debug_struct("Effect::Event")
3174                .field("entity_id", entity_id)
3175                .finish(),
3176            Effect::GlobalSubscription {
3177                type_id,
3178                subscription_id,
3179                ..
3180            } => f
3181                .debug_struct("Effect::Subscribe")
3182                .field("type_id", type_id)
3183                .field("subscription_id", subscription_id)
3184                .finish(),
3185            Effect::GlobalEvent { payload, .. } => f
3186                .debug_struct("Effect::GlobalEvent")
3187                .field("type_id", &(&*payload).type_id())
3188                .finish(),
3189            Effect::Observation {
3190                entity_id,
3191                subscription_id,
3192                ..
3193            } => f
3194                .debug_struct("Effect::Observation")
3195                .field("entity_id", entity_id)
3196                .field("subscription_id", subscription_id)
3197                .finish(),
3198            Effect::ModelNotification { model_id } => f
3199                .debug_struct("Effect::ModelNotification")
3200                .field("model_id", model_id)
3201                .finish(),
3202            Effect::ViewNotification { window_id, view_id } => f
3203                .debug_struct("Effect::ViewNotification")
3204                .field("window_id", window_id)
3205                .field("view_id", view_id)
3206                .finish(),
3207            Effect::GlobalNotification { type_id } => f
3208                .debug_struct("Effect::GlobalNotification")
3209                .field("type_id", type_id)
3210                .finish(),
3211            Effect::Deferred { .. } => f.debug_struct("Effect::Deferred").finish(),
3212            Effect::ModelRelease { model_id, .. } => f
3213                .debug_struct("Effect::ModelRelease")
3214                .field("model_id", model_id)
3215                .finish(),
3216            Effect::ViewRelease { view_id, .. } => f
3217                .debug_struct("Effect::ViewRelease")
3218                .field("view_id", view_id)
3219                .finish(),
3220            Effect::Focus { window_id, view_id } => f
3221                .debug_struct("Effect::Focus")
3222                .field("window_id", window_id)
3223                .field("view_id", view_id)
3224                .finish(),
3225            Effect::FocusObservation {
3226                view_id,
3227                subscription_id,
3228                ..
3229            } => f
3230                .debug_struct("Effect::FocusObservation")
3231                .field("view_id", view_id)
3232                .field("subscription_id", subscription_id)
3233                .finish(),
3234            Effect::ActionDispatchNotification { action_id, .. } => f
3235                .debug_struct("Effect::ActionDispatchNotification")
3236                .field("action_id", action_id)
3237                .finish(),
3238            Effect::ResizeWindow { window_id } => f
3239                .debug_struct("Effect::RefreshWindow")
3240                .field("window_id", window_id)
3241                .finish(),
3242            Effect::WindowActivationObservation {
3243                window_id,
3244                subscription_id,
3245                ..
3246            } => f
3247                .debug_struct("Effect::WindowActivationObservation")
3248                .field("window_id", window_id)
3249                .field("subscription_id", subscription_id)
3250                .finish(),
3251            Effect::ActivateWindow {
3252                window_id,
3253                is_active,
3254            } => f
3255                .debug_struct("Effect::ActivateWindow")
3256                .field("window_id", window_id)
3257                .field("is_active", is_active)
3258                .finish(),
3259            Effect::RefreshWindows => f.debug_struct("Effect::FullViewRefresh").finish(),
3260            Effect::WindowShouldCloseSubscription { window_id, .. } => f
3261                .debug_struct("Effect::WindowShouldCloseSubscription")
3262                .field("window_id", window_id)
3263                .finish(),
3264        }
3265    }
3266}
3267
3268pub trait AnyModel {
3269    fn as_any(&self) -> &dyn Any;
3270    fn as_any_mut(&mut self) -> &mut dyn Any;
3271    fn release(&mut self, cx: &mut MutableAppContext);
3272    fn app_will_quit(
3273        &mut self,
3274        cx: &mut MutableAppContext,
3275    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
3276}
3277
3278impl<T> AnyModel for T
3279where
3280    T: Entity,
3281{
3282    fn as_any(&self) -> &dyn Any {
3283        self
3284    }
3285
3286    fn as_any_mut(&mut self) -> &mut dyn Any {
3287        self
3288    }
3289
3290    fn release(&mut self, cx: &mut MutableAppContext) {
3291        self.release(cx);
3292    }
3293
3294    fn app_will_quit(
3295        &mut self,
3296        cx: &mut MutableAppContext,
3297    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
3298        self.app_will_quit(cx)
3299    }
3300}
3301
3302pub trait AnyView {
3303    fn as_any(&self) -> &dyn Any;
3304    fn as_any_mut(&mut self) -> &mut dyn Any;
3305    fn release(&mut self, cx: &mut MutableAppContext);
3306    fn app_will_quit(
3307        &mut self,
3308        cx: &mut MutableAppContext,
3309    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
3310    fn ui_name(&self) -> &'static str;
3311    fn render<'a>(&mut self, params: RenderParams, cx: &mut MutableAppContext) -> ElementBox;
3312    fn on_focus(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize);
3313    fn on_blur(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize);
3314    fn keymap_context(&self, cx: &AppContext) -> keymap::Context;
3315    fn debug_json(&self, cx: &AppContext) -> serde_json::Value;
3316
3317    fn text_for_range(&self, range: Range<usize>, cx: &AppContext) -> Option<String>;
3318    fn selected_text_range(&self, cx: &AppContext) -> Option<Range<usize>>;
3319    fn marked_text_range(&self, cx: &AppContext) -> Option<Range<usize>>;
3320    fn unmark_text(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize);
3321    fn replace_text_in_range(
3322        &mut self,
3323        range: Option<Range<usize>>,
3324        text: &str,
3325        cx: &mut MutableAppContext,
3326        window_id: usize,
3327        view_id: usize,
3328    );
3329    fn replace_and_mark_text_in_range(
3330        &mut self,
3331        range: Option<Range<usize>>,
3332        new_text: &str,
3333        new_selected_range: Option<Range<usize>>,
3334        cx: &mut MutableAppContext,
3335        window_id: usize,
3336        view_id: usize,
3337    );
3338}
3339
3340impl<T> AnyView for T
3341where
3342    T: View,
3343{
3344    fn as_any(&self) -> &dyn Any {
3345        self
3346    }
3347
3348    fn as_any_mut(&mut self) -> &mut dyn Any {
3349        self
3350    }
3351
3352    fn release(&mut self, cx: &mut MutableAppContext) {
3353        self.release(cx);
3354    }
3355
3356    fn app_will_quit(
3357        &mut self,
3358        cx: &mut MutableAppContext,
3359    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
3360        self.app_will_quit(cx)
3361    }
3362
3363    fn ui_name(&self) -> &'static str {
3364        T::ui_name()
3365    }
3366
3367    fn render<'a>(&mut self, params: RenderParams, cx: &mut MutableAppContext) -> ElementBox {
3368        View::render(self, &mut RenderContext::new(params, cx))
3369    }
3370
3371    fn on_focus(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize) {
3372        let mut cx = ViewContext::new(cx, window_id, view_id);
3373        View::on_focus(self, &mut cx);
3374    }
3375
3376    fn on_blur(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize) {
3377        let mut cx = ViewContext::new(cx, window_id, view_id);
3378        View::on_blur(self, &mut cx);
3379    }
3380
3381    fn keymap_context(&self, cx: &AppContext) -> keymap::Context {
3382        View::keymap_context(self, cx)
3383    }
3384
3385    fn debug_json(&self, cx: &AppContext) -> serde_json::Value {
3386        View::debug_json(self, cx)
3387    }
3388
3389    fn text_for_range(&self, range: Range<usize>, cx: &AppContext) -> Option<String> {
3390        View::text_for_range(self, range, cx)
3391    }
3392
3393    fn selected_text_range(&self, cx: &AppContext) -> Option<Range<usize>> {
3394        View::selected_text_range(self, cx)
3395    }
3396
3397    fn marked_text_range(&self, cx: &AppContext) -> Option<Range<usize>> {
3398        View::marked_text_range(self, cx)
3399    }
3400
3401    fn unmark_text(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize) {
3402        let mut cx = ViewContext::new(cx, window_id, view_id);
3403        View::unmark_text(self, &mut cx)
3404    }
3405
3406    fn replace_text_in_range(
3407        &mut self,
3408        range: Option<Range<usize>>,
3409        text: &str,
3410        cx: &mut MutableAppContext,
3411        window_id: usize,
3412        view_id: usize,
3413    ) {
3414        let mut cx = ViewContext::new(cx, window_id, view_id);
3415        View::replace_text_in_range(self, range, text, &mut cx)
3416    }
3417
3418    fn replace_and_mark_text_in_range(
3419        &mut self,
3420        range: Option<Range<usize>>,
3421        new_text: &str,
3422        new_selected_range: Option<Range<usize>>,
3423        cx: &mut MutableAppContext,
3424        window_id: usize,
3425        view_id: usize,
3426    ) {
3427        let mut cx = ViewContext::new(cx, window_id, view_id);
3428        View::replace_and_mark_text_in_range(self, range, new_text, new_selected_range, &mut cx)
3429    }
3430}
3431
3432pub struct ModelContext<'a, T: ?Sized> {
3433    app: &'a mut MutableAppContext,
3434    model_id: usize,
3435    model_type: PhantomData<T>,
3436    halt_stream: bool,
3437}
3438
3439impl<'a, T: Entity> ModelContext<'a, T> {
3440    fn new(app: &'a mut MutableAppContext, model_id: usize) -> Self {
3441        Self {
3442            app,
3443            model_id,
3444            model_type: PhantomData,
3445            halt_stream: false,
3446        }
3447    }
3448
3449    pub fn background(&self) -> &Arc<executor::Background> {
3450        &self.app.cx.background
3451    }
3452
3453    pub fn halt_stream(&mut self) {
3454        self.halt_stream = true;
3455    }
3456
3457    pub fn model_id(&self) -> usize {
3458        self.model_id
3459    }
3460
3461    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
3462    where
3463        S: Entity,
3464        F: FnOnce(&mut ModelContext<S>) -> S,
3465    {
3466        self.app.add_model(build_model)
3467    }
3468
3469    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut T, &mut ModelContext<T>)) {
3470        let handle = self.handle();
3471        self.app.defer(move |cx| {
3472            handle.update(cx, |model, cx| {
3473                callback(model, cx);
3474            })
3475        })
3476    }
3477
3478    pub fn emit(&mut self, payload: T::Event) {
3479        self.app.pending_effects.push_back(Effect::Event {
3480            entity_id: self.model_id,
3481            payload: Box::new(payload),
3482        });
3483    }
3484
3485    pub fn notify(&mut self) {
3486        self.app.notify_model(self.model_id);
3487    }
3488
3489    pub fn subscribe<S: Entity, F>(
3490        &mut self,
3491        handle: &ModelHandle<S>,
3492        mut callback: F,
3493    ) -> Subscription
3494    where
3495        S::Event: 'static,
3496        F: 'static + FnMut(&mut T, ModelHandle<S>, &S::Event, &mut ModelContext<T>),
3497    {
3498        let subscriber = self.weak_handle();
3499        self.app
3500            .subscribe_internal(handle, move |emitter, event, cx| {
3501                if let Some(subscriber) = subscriber.upgrade(cx) {
3502                    subscriber.update(cx, |subscriber, cx| {
3503                        callback(subscriber, emitter, event, cx);
3504                    });
3505                    true
3506                } else {
3507                    false
3508                }
3509            })
3510    }
3511
3512    pub fn observe<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F) -> Subscription
3513    where
3514        S: Entity,
3515        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ModelContext<T>),
3516    {
3517        let observer = self.weak_handle();
3518        self.app.observe_internal(handle, move |observed, cx| {
3519            if let Some(observer) = observer.upgrade(cx) {
3520                observer.update(cx, |observer, cx| {
3521                    callback(observer, observed, cx);
3522                });
3523                true
3524            } else {
3525                false
3526            }
3527        })
3528    }
3529
3530    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
3531    where
3532        G: Any,
3533        F: 'static + FnMut(&mut T, &mut ModelContext<T>),
3534    {
3535        let observer = self.weak_handle();
3536        self.app.observe_global::<G, _>(move |cx| {
3537            if let Some(observer) = observer.upgrade(cx) {
3538                observer.update(cx, |observer, cx| callback(observer, cx));
3539            }
3540        })
3541    }
3542
3543    pub fn observe_release<S, F>(
3544        &mut self,
3545        handle: &ModelHandle<S>,
3546        mut callback: F,
3547    ) -> Subscription
3548    where
3549        S: Entity,
3550        F: 'static + FnMut(&mut T, &S, &mut ModelContext<T>),
3551    {
3552        let observer = self.weak_handle();
3553        self.app.observe_release(handle, move |released, cx| {
3554            if let Some(observer) = observer.upgrade(cx) {
3555                observer.update(cx, |observer, cx| {
3556                    callback(observer, released, cx);
3557                });
3558            }
3559        })
3560    }
3561
3562    pub fn handle(&self) -> ModelHandle<T> {
3563        ModelHandle::new(self.model_id, &self.app.cx.ref_counts)
3564    }
3565
3566    pub fn weak_handle(&self) -> WeakModelHandle<T> {
3567        WeakModelHandle::new(self.model_id)
3568    }
3569
3570    pub fn spawn<F, Fut, S>(&self, f: F) -> Task<S>
3571    where
3572        F: FnOnce(ModelHandle<T>, AsyncAppContext) -> Fut,
3573        Fut: 'static + Future<Output = S>,
3574        S: 'static,
3575    {
3576        let handle = self.handle();
3577        self.app.spawn(|cx| f(handle, cx))
3578    }
3579
3580    pub fn spawn_weak<F, Fut, S>(&self, f: F) -> Task<S>
3581    where
3582        F: FnOnce(WeakModelHandle<T>, AsyncAppContext) -> Fut,
3583        Fut: 'static + Future<Output = S>,
3584        S: 'static,
3585    {
3586        let handle = self.weak_handle();
3587        self.app.spawn(|cx| f(handle, cx))
3588    }
3589}
3590
3591impl<M> AsRef<AppContext> for ModelContext<'_, M> {
3592    fn as_ref(&self) -> &AppContext {
3593        &self.app.cx
3594    }
3595}
3596
3597impl<M> AsMut<MutableAppContext> for ModelContext<'_, M> {
3598    fn as_mut(&mut self) -> &mut MutableAppContext {
3599        self.app
3600    }
3601}
3602
3603impl<M> ReadModel for ModelContext<'_, M> {
3604    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
3605        self.app.read_model(handle)
3606    }
3607}
3608
3609impl<M> UpdateModel for ModelContext<'_, M> {
3610    fn update_model<T: Entity, V>(
3611        &mut self,
3612        handle: &ModelHandle<T>,
3613        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> V,
3614    ) -> V {
3615        self.app.update_model(handle, update)
3616    }
3617}
3618
3619impl<M> UpgradeModelHandle for ModelContext<'_, M> {
3620    fn upgrade_model_handle<T: Entity>(
3621        &self,
3622        handle: &WeakModelHandle<T>,
3623    ) -> Option<ModelHandle<T>> {
3624        self.cx.upgrade_model_handle(handle)
3625    }
3626
3627    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
3628        self.cx.model_handle_is_upgradable(handle)
3629    }
3630
3631    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
3632        self.cx.upgrade_any_model_handle(handle)
3633    }
3634}
3635
3636impl<M> Deref for ModelContext<'_, M> {
3637    type Target = MutableAppContext;
3638
3639    fn deref(&self) -> &Self::Target {
3640        &self.app
3641    }
3642}
3643
3644impl<M> DerefMut for ModelContext<'_, M> {
3645    fn deref_mut(&mut self) -> &mut Self::Target {
3646        &mut self.app
3647    }
3648}
3649
3650pub struct ViewContext<'a, T: ?Sized> {
3651    app: &'a mut MutableAppContext,
3652    window_id: usize,
3653    view_id: usize,
3654    view_type: PhantomData<T>,
3655}
3656
3657impl<'a, T: View> ViewContext<'a, T> {
3658    fn new(app: &'a mut MutableAppContext, window_id: usize, view_id: usize) -> Self {
3659        Self {
3660            app,
3661            window_id,
3662            view_id,
3663            view_type: PhantomData,
3664        }
3665    }
3666
3667    pub fn handle(&self) -> ViewHandle<T> {
3668        ViewHandle::new(self.window_id, self.view_id, &self.app.cx.ref_counts)
3669    }
3670
3671    pub fn weak_handle(&self) -> WeakViewHandle<T> {
3672        WeakViewHandle::new(self.window_id, self.view_id)
3673    }
3674
3675    pub fn window_id(&self) -> usize {
3676        self.window_id
3677    }
3678
3679    pub fn view_id(&self) -> usize {
3680        self.view_id
3681    }
3682
3683    pub fn foreground(&self) -> &Rc<executor::Foreground> {
3684        self.app.foreground()
3685    }
3686
3687    pub fn background_executor(&self) -> &Arc<executor::Background> {
3688        &self.app.cx.background
3689    }
3690
3691    pub fn platform(&self) -> Arc<dyn Platform> {
3692        self.app.platform()
3693    }
3694
3695    pub fn show_character_palette(&self) {
3696        self.app.show_character_palette(self.window_id);
3697    }
3698
3699    pub fn minimize_window(&self) {
3700        self.app.minimize_window(self.window_id)
3701    }
3702
3703    pub fn zoom_window(&self) {
3704        self.app.zoom_window(self.window_id)
3705    }
3706
3707    pub fn prompt(
3708        &self,
3709        level: PromptLevel,
3710        msg: &str,
3711        answers: &[&str],
3712    ) -> oneshot::Receiver<usize> {
3713        self.app.prompt(self.window_id, level, msg, answers)
3714    }
3715
3716    pub fn prompt_for_paths(
3717        &self,
3718        options: PathPromptOptions,
3719    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
3720        self.app.prompt_for_paths(options)
3721    }
3722
3723    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
3724        self.app.prompt_for_new_path(directory)
3725    }
3726
3727    pub fn debug_elements(&self) -> crate::json::Value {
3728        self.app.debug_elements(self.window_id).unwrap()
3729    }
3730
3731    pub fn focus<S>(&mut self, handle: S)
3732    where
3733        S: Into<AnyViewHandle>,
3734    {
3735        let handle = handle.into();
3736        self.app.focus(handle.window_id, Some(handle.view_id));
3737    }
3738
3739    pub fn focus_self(&mut self) {
3740        self.app.focus(self.window_id, Some(self.view_id));
3741    }
3742
3743    pub fn is_self_focused(&self) -> bool {
3744        self.app.focused_view_id(self.window_id) == Some(self.view_id)
3745    }
3746
3747    pub fn blur(&mut self) {
3748        self.app.focus(self.window_id, None);
3749    }
3750
3751    pub fn set_window_title(&mut self, title: &str) {
3752        let window_id = self.window_id();
3753        if let Some((_, window)) = self.presenters_and_platform_windows.get_mut(&window_id) {
3754            window.set_title(title);
3755        }
3756    }
3757
3758    pub fn set_window_edited(&mut self, edited: bool) {
3759        let window_id = self.window_id();
3760        if let Some((_, window)) = self.presenters_and_platform_windows.get_mut(&window_id) {
3761            window.set_edited(edited);
3762        }
3763    }
3764
3765    pub fn on_window_should_close<F>(&mut self, mut callback: F)
3766    where
3767        F: 'static + FnMut(&mut T, &mut ViewContext<T>) -> bool,
3768    {
3769        let window_id = self.window_id();
3770        let view = self.weak_handle();
3771        self.pending_effects
3772            .push_back(Effect::WindowShouldCloseSubscription {
3773                window_id,
3774                callback: Box::new(move |cx| {
3775                    if let Some(view) = view.upgrade(cx) {
3776                        view.update(cx, |view, cx| callback(view, cx))
3777                    } else {
3778                        true
3779                    }
3780                }),
3781            });
3782    }
3783
3784    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
3785    where
3786        S: Entity,
3787        F: FnOnce(&mut ModelContext<S>) -> S,
3788    {
3789        self.app.add_model(build_model)
3790    }
3791
3792    pub fn add_view<S, F>(&mut self, build_view: F) -> ViewHandle<S>
3793    where
3794        S: View,
3795        F: FnOnce(&mut ViewContext<S>) -> S,
3796    {
3797        self.app.add_view(self.window_id, build_view)
3798    }
3799
3800    pub fn add_option_view<S, F>(&mut self, build_view: F) -> Option<ViewHandle<S>>
3801    where
3802        S: View,
3803        F: FnOnce(&mut ViewContext<S>) -> Option<S>,
3804    {
3805        self.app.add_option_view(self.window_id, build_view)
3806    }
3807
3808    pub fn replace_root_view<V, F>(&mut self, build_root_view: F) -> ViewHandle<V>
3809    where
3810        V: View,
3811        F: FnOnce(&mut ViewContext<V>) -> V,
3812    {
3813        let window_id = self.window_id;
3814        self.update(|this| {
3815            let root_view = this.add_view(window_id, build_root_view);
3816            let window = this.cx.windows.get_mut(&window_id).unwrap();
3817            window.root_view = root_view.clone().into();
3818            window.focused_view_id = Some(root_view.id());
3819            root_view
3820        })
3821    }
3822
3823    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
3824    where
3825        E: Entity,
3826        E::Event: 'static,
3827        H: Handle<E>,
3828        F: 'static + FnMut(&mut T, H, &E::Event, &mut ViewContext<T>),
3829    {
3830        let subscriber = self.weak_handle();
3831        self.app
3832            .subscribe_internal(handle, move |emitter, event, cx| {
3833                if let Some(subscriber) = subscriber.upgrade(cx) {
3834                    subscriber.update(cx, |subscriber, cx| {
3835                        callback(subscriber, emitter, event, cx);
3836                    });
3837                    true
3838                } else {
3839                    false
3840                }
3841            })
3842    }
3843
3844    pub fn observe<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
3845    where
3846        E: Entity,
3847        H: Handle<E>,
3848        F: 'static + FnMut(&mut T, H, &mut ViewContext<T>),
3849    {
3850        let observer = self.weak_handle();
3851        self.app.observe_internal(handle, move |observed, cx| {
3852            if let Some(observer) = observer.upgrade(cx) {
3853                observer.update(cx, |observer, cx| {
3854                    callback(observer, observed, cx);
3855                });
3856                true
3857            } else {
3858                false
3859            }
3860        })
3861    }
3862
3863    pub fn observe_focus<F, V>(&mut self, handle: &ViewHandle<V>, mut callback: F) -> Subscription
3864    where
3865        F: 'static + FnMut(&mut T, ViewHandle<V>, bool, &mut ViewContext<T>),
3866        V: View,
3867    {
3868        let observer = self.weak_handle();
3869        self.app
3870            .observe_focus(handle, move |observed, focused, cx| {
3871                if let Some(observer) = observer.upgrade(cx) {
3872                    observer.update(cx, |observer, cx| {
3873                        callback(observer, observed, focused, cx);
3874                    });
3875                    true
3876                } else {
3877                    false
3878                }
3879            })
3880    }
3881
3882    pub fn observe_release<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
3883    where
3884        E: Entity,
3885        H: Handle<E>,
3886        F: 'static + FnMut(&mut T, &E, &mut ViewContext<T>),
3887    {
3888        let observer = self.weak_handle();
3889        self.app.observe_release(handle, move |released, cx| {
3890            if let Some(observer) = observer.upgrade(cx) {
3891                observer.update(cx, |observer, cx| {
3892                    callback(observer, released, cx);
3893                });
3894            }
3895        })
3896    }
3897
3898    pub fn observe_actions<F>(&mut self, mut callback: F) -> Subscription
3899    where
3900        F: 'static + FnMut(&mut T, TypeId, &mut ViewContext<T>),
3901    {
3902        let observer = self.weak_handle();
3903        self.app.observe_actions(move |action_id, cx| {
3904            if let Some(observer) = observer.upgrade(cx) {
3905                observer.update(cx, |observer, cx| {
3906                    callback(observer, action_id, cx);
3907                });
3908            }
3909        })
3910    }
3911
3912    pub fn observe_window_activation<F>(&mut self, mut callback: F) -> Subscription
3913    where
3914        F: 'static + FnMut(&mut T, bool, &mut ViewContext<T>),
3915    {
3916        let observer = self.weak_handle();
3917        self.app
3918            .observe_window_activation(self.window_id(), move |active, cx| {
3919                if let Some(observer) = observer.upgrade(cx) {
3920                    observer.update(cx, |observer, cx| {
3921                        callback(observer, active, cx);
3922                    });
3923                    true
3924                } else {
3925                    false
3926                }
3927            })
3928    }
3929
3930    pub fn emit(&mut self, payload: T::Event) {
3931        self.app.pending_effects.push_back(Effect::Event {
3932            entity_id: self.view_id,
3933            payload: Box::new(payload),
3934        });
3935    }
3936
3937    pub fn notify(&mut self) {
3938        self.app.notify_view(self.window_id, self.view_id);
3939    }
3940
3941    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut T, &mut ViewContext<T>)) {
3942        let handle = self.handle();
3943        self.app.defer(move |cx| {
3944            handle.update(cx, |view, cx| {
3945                callback(view, cx);
3946            })
3947        })
3948    }
3949
3950    pub fn after_window_update(
3951        &mut self,
3952        callback: impl 'static + FnOnce(&mut T, &mut ViewContext<T>),
3953    ) {
3954        let handle = self.handle();
3955        self.app.after_window_update(move |cx| {
3956            handle.update(cx, |view, cx| {
3957                callback(view, cx);
3958            })
3959        })
3960    }
3961
3962    pub fn propagate_action(&mut self) {
3963        self.app.halt_action_dispatch = false;
3964    }
3965
3966    pub fn spawn<F, Fut, S>(&self, f: F) -> Task<S>
3967    where
3968        F: FnOnce(ViewHandle<T>, AsyncAppContext) -> Fut,
3969        Fut: 'static + Future<Output = S>,
3970        S: 'static,
3971    {
3972        let handle = self.handle();
3973        self.app.spawn(|cx| f(handle, cx))
3974    }
3975
3976    pub fn spawn_weak<F, Fut, S>(&self, f: F) -> Task<S>
3977    where
3978        F: FnOnce(WeakViewHandle<T>, AsyncAppContext) -> Fut,
3979        Fut: 'static + Future<Output = S>,
3980        S: 'static,
3981    {
3982        let handle = self.weak_handle();
3983        self.app.spawn(|cx| f(handle, cx))
3984    }
3985}
3986
3987pub struct RenderParams {
3988    pub window_id: usize,
3989    pub view_id: usize,
3990    pub titlebar_height: f32,
3991    pub hovered_region_ids: HashSet<MouseRegionId>,
3992    pub clicked_region_id: Option<MouseRegionId>,
3993    pub right_clicked_region_id: Option<MouseRegionId>,
3994    pub refreshing: bool,
3995}
3996
3997pub struct RenderContext<'a, T: View> {
3998    pub(crate) window_id: usize,
3999    pub(crate) view_id: usize,
4000    pub(crate) view_type: PhantomData<T>,
4001    pub(crate) hovered_region_ids: HashSet<MouseRegionId>,
4002    pub(crate) clicked_region_id: Option<MouseRegionId>,
4003    pub(crate) right_clicked_region_id: Option<MouseRegionId>,
4004    pub app: &'a mut MutableAppContext,
4005    pub titlebar_height: f32,
4006    pub refreshing: bool,
4007}
4008
4009#[derive(Clone, Copy, Default)]
4010pub struct MouseState {
4011    pub hovered: bool,
4012    pub clicked: bool,
4013    pub right_clicked: bool,
4014}
4015
4016impl<'a, V: View> RenderContext<'a, V> {
4017    fn new(params: RenderParams, app: &'a mut MutableAppContext) -> Self {
4018        Self {
4019            app,
4020            window_id: params.window_id,
4021            view_id: params.view_id,
4022            view_type: PhantomData,
4023            titlebar_height: params.titlebar_height,
4024            hovered_region_ids: params.hovered_region_ids.clone(),
4025            clicked_region_id: params.clicked_region_id,
4026            right_clicked_region_id: params.right_clicked_region_id,
4027            refreshing: params.refreshing,
4028        }
4029    }
4030
4031    pub fn handle(&self) -> WeakViewHandle<V> {
4032        WeakViewHandle::new(self.window_id, self.view_id)
4033    }
4034
4035    pub fn view_id(&self) -> usize {
4036        self.view_id
4037    }
4038
4039    pub fn mouse_state<Tag: 'static>(&self, region_id: usize) -> MouseState {
4040        let region_id = MouseRegionId {
4041            view_id: self.view_id,
4042            discriminant: (TypeId::of::<Tag>(), region_id),
4043        };
4044        MouseState {
4045            hovered: self.hovered_region_ids.contains(&region_id),
4046            clicked: self.clicked_region_id == Some(region_id),
4047            right_clicked: self.right_clicked_region_id == Some(region_id),
4048        }
4049    }
4050
4051    pub fn element_state<Tag: 'static, T: 'static + Default>(
4052        &mut self,
4053        element_id: usize,
4054    ) -> ElementStateHandle<T> {
4055        let id = ElementStateId {
4056            view_id: self.view_id(),
4057            element_id,
4058            tag: TypeId::of::<Tag>(),
4059        };
4060        self.cx
4061            .element_states
4062            .entry(id)
4063            .or_insert_with(|| Box::new(T::default()));
4064        ElementStateHandle::new(id, self.frame_count, &self.cx.ref_counts)
4065    }
4066}
4067
4068impl AsRef<AppContext> for &AppContext {
4069    fn as_ref(&self) -> &AppContext {
4070        self
4071    }
4072}
4073
4074impl<V: View> Deref for RenderContext<'_, V> {
4075    type Target = MutableAppContext;
4076
4077    fn deref(&self) -> &Self::Target {
4078        self.app
4079    }
4080}
4081
4082impl<V: View> DerefMut for RenderContext<'_, V> {
4083    fn deref_mut(&mut self) -> &mut Self::Target {
4084        self.app
4085    }
4086}
4087
4088impl<V: View> ReadModel for RenderContext<'_, V> {
4089    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
4090        self.app.read_model(handle)
4091    }
4092}
4093
4094impl<V: View> UpdateModel for RenderContext<'_, V> {
4095    fn update_model<T: Entity, O>(
4096        &mut self,
4097        handle: &ModelHandle<T>,
4098        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
4099    ) -> O {
4100        self.app.update_model(handle, update)
4101    }
4102}
4103
4104impl<V: View> ReadView for RenderContext<'_, V> {
4105    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
4106        self.app.read_view(handle)
4107    }
4108}
4109
4110impl<M> AsRef<AppContext> for ViewContext<'_, M> {
4111    fn as_ref(&self) -> &AppContext {
4112        &self.app.cx
4113    }
4114}
4115
4116impl<M> Deref for ViewContext<'_, M> {
4117    type Target = MutableAppContext;
4118
4119    fn deref(&self) -> &Self::Target {
4120        &self.app
4121    }
4122}
4123
4124impl<M> DerefMut for ViewContext<'_, M> {
4125    fn deref_mut(&mut self) -> &mut Self::Target {
4126        &mut self.app
4127    }
4128}
4129
4130impl<M> AsMut<MutableAppContext> for ViewContext<'_, M> {
4131    fn as_mut(&mut self) -> &mut MutableAppContext {
4132        self.app
4133    }
4134}
4135
4136impl<V> ReadModel for ViewContext<'_, V> {
4137    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
4138        self.app.read_model(handle)
4139    }
4140}
4141
4142impl<V> UpgradeModelHandle for ViewContext<'_, V> {
4143    fn upgrade_model_handle<T: Entity>(
4144        &self,
4145        handle: &WeakModelHandle<T>,
4146    ) -> Option<ModelHandle<T>> {
4147        self.cx.upgrade_model_handle(handle)
4148    }
4149
4150    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
4151        self.cx.model_handle_is_upgradable(handle)
4152    }
4153
4154    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
4155        self.cx.upgrade_any_model_handle(handle)
4156    }
4157}
4158
4159impl<V> UpgradeViewHandle for ViewContext<'_, V> {
4160    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
4161        self.cx.upgrade_view_handle(handle)
4162    }
4163
4164    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
4165        self.cx.upgrade_any_view_handle(handle)
4166    }
4167}
4168
4169impl<V: View> UpgradeViewHandle for RenderContext<'_, V> {
4170    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
4171        self.cx.upgrade_view_handle(handle)
4172    }
4173
4174    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
4175        self.cx.upgrade_any_view_handle(handle)
4176    }
4177}
4178
4179impl<V: View> UpdateModel for ViewContext<'_, V> {
4180    fn update_model<T: Entity, O>(
4181        &mut self,
4182        handle: &ModelHandle<T>,
4183        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
4184    ) -> O {
4185        self.app.update_model(handle, update)
4186    }
4187}
4188
4189impl<V: View> ReadView for ViewContext<'_, V> {
4190    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
4191        self.app.read_view(handle)
4192    }
4193}
4194
4195impl<V: View> UpdateView for ViewContext<'_, V> {
4196    fn update_view<T, S>(
4197        &mut self,
4198        handle: &ViewHandle<T>,
4199        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
4200    ) -> S
4201    where
4202        T: View,
4203    {
4204        self.app.update_view(handle, update)
4205    }
4206}
4207
4208pub trait Handle<T> {
4209    type Weak: 'static;
4210    fn id(&self) -> usize;
4211    fn location(&self) -> EntityLocation;
4212    fn downgrade(&self) -> Self::Weak;
4213    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
4214    where
4215        Self: Sized;
4216}
4217
4218pub trait WeakHandle {
4219    fn id(&self) -> usize;
4220}
4221
4222#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
4223pub enum EntityLocation {
4224    Model(usize),
4225    View(usize, usize),
4226}
4227
4228pub struct ModelHandle<T: Entity> {
4229    model_id: usize,
4230    model_type: PhantomData<T>,
4231    ref_counts: Arc<Mutex<RefCounts>>,
4232
4233    #[cfg(any(test, feature = "test-support"))]
4234    handle_id: usize,
4235}
4236
4237impl<T: Entity> ModelHandle<T> {
4238    fn new(model_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
4239        ref_counts.lock().inc_model(model_id);
4240
4241        #[cfg(any(test, feature = "test-support"))]
4242        let handle_id = ref_counts
4243            .lock()
4244            .leak_detector
4245            .lock()
4246            .handle_created(Some(type_name::<T>()), model_id);
4247
4248        Self {
4249            model_id,
4250            model_type: PhantomData,
4251            ref_counts: ref_counts.clone(),
4252
4253            #[cfg(any(test, feature = "test-support"))]
4254            handle_id,
4255        }
4256    }
4257
4258    pub fn downgrade(&self) -> WeakModelHandle<T> {
4259        WeakModelHandle::new(self.model_id)
4260    }
4261
4262    pub fn id(&self) -> usize {
4263        self.model_id
4264    }
4265
4266    pub fn read<'a, C: ReadModel>(&self, cx: &'a C) -> &'a T {
4267        cx.read_model(self)
4268    }
4269
4270    pub fn read_with<'a, C, F, S>(&self, cx: &C, read: F) -> S
4271    where
4272        C: ReadModelWith,
4273        F: FnOnce(&T, &AppContext) -> S,
4274    {
4275        let mut read = Some(read);
4276        cx.read_model_with(self, &mut |model, cx| {
4277            let read = read.take().unwrap();
4278            read(model, cx)
4279        })
4280    }
4281
4282    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
4283    where
4284        C: UpdateModel,
4285        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
4286    {
4287        let mut update = Some(update);
4288        cx.update_model(self, &mut |model, cx| {
4289            let update = update.take().unwrap();
4290            update(model, cx)
4291        })
4292    }
4293
4294    #[cfg(any(test, feature = "test-support"))]
4295    pub fn next_notification(&self, cx: &TestAppContext) -> impl Future<Output = ()> {
4296        let (tx, mut rx) = futures::channel::mpsc::unbounded();
4297        let mut cx = cx.cx.borrow_mut();
4298        let subscription = cx.observe(self, move |_, _| {
4299            tx.unbounded_send(()).ok();
4300        });
4301
4302        let duration = if std::env::var("CI").is_ok() {
4303            Duration::from_secs(5)
4304        } else {
4305            Duration::from_secs(1)
4306        };
4307
4308        async move {
4309            let notification = crate::util::timeout(duration, rx.next())
4310                .await
4311                .expect("next notification timed out");
4312            drop(subscription);
4313            notification.expect("model dropped while test was waiting for its next notification")
4314        }
4315    }
4316
4317    #[cfg(any(test, feature = "test-support"))]
4318    pub fn next_event(&self, cx: &TestAppContext) -> impl Future<Output = T::Event>
4319    where
4320        T::Event: Clone,
4321    {
4322        let (tx, mut rx) = futures::channel::mpsc::unbounded();
4323        let mut cx = cx.cx.borrow_mut();
4324        let subscription = cx.subscribe(self, move |_, event, _| {
4325            tx.unbounded_send(event.clone()).ok();
4326        });
4327
4328        let duration = if std::env::var("CI").is_ok() {
4329            Duration::from_secs(5)
4330        } else {
4331            Duration::from_secs(1)
4332        };
4333
4334        cx.foreground.start_waiting();
4335        async move {
4336            let event = crate::util::timeout(duration, rx.next())
4337                .await
4338                .expect("next event timed out");
4339            drop(subscription);
4340            event.expect("model dropped while test was waiting for its next event")
4341        }
4342    }
4343
4344    #[cfg(any(test, feature = "test-support"))]
4345    pub fn condition(
4346        &self,
4347        cx: &TestAppContext,
4348        mut predicate: impl FnMut(&T, &AppContext) -> bool,
4349    ) -> impl Future<Output = ()> {
4350        let (tx, mut rx) = futures::channel::mpsc::unbounded();
4351
4352        let mut cx = cx.cx.borrow_mut();
4353        let subscriptions = (
4354            cx.observe(self, {
4355                let tx = tx.clone();
4356                move |_, _| {
4357                    tx.unbounded_send(()).ok();
4358                }
4359            }),
4360            cx.subscribe(self, {
4361                let tx = tx.clone();
4362                move |_, _, _| {
4363                    tx.unbounded_send(()).ok();
4364                }
4365            }),
4366        );
4367
4368        let cx = cx.weak_self.as_ref().unwrap().upgrade().unwrap();
4369        let handle = self.downgrade();
4370        let duration = if std::env::var("CI").is_ok() {
4371            Duration::from_secs(5)
4372        } else {
4373            Duration::from_secs(1)
4374        };
4375
4376        async move {
4377            crate::util::timeout(duration, async move {
4378                loop {
4379                    {
4380                        let cx = cx.borrow();
4381                        let cx = cx.as_ref();
4382                        if predicate(
4383                            handle
4384                                .upgrade(cx)
4385                                .expect("model dropped with pending condition")
4386                                .read(cx),
4387                            cx,
4388                        ) {
4389                            break;
4390                        }
4391                    }
4392
4393                    cx.borrow().foreground().start_waiting();
4394                    rx.next()
4395                        .await
4396                        .expect("model dropped with pending condition");
4397                    cx.borrow().foreground().finish_waiting();
4398                }
4399            })
4400            .await
4401            .expect("condition timed out");
4402            drop(subscriptions);
4403        }
4404    }
4405}
4406
4407impl<T: Entity> Clone for ModelHandle<T> {
4408    fn clone(&self) -> Self {
4409        Self::new(self.model_id, &self.ref_counts)
4410    }
4411}
4412
4413impl<T: Entity> PartialEq for ModelHandle<T> {
4414    fn eq(&self, other: &Self) -> bool {
4415        self.model_id == other.model_id
4416    }
4417}
4418
4419impl<T: Entity> Eq for ModelHandle<T> {}
4420
4421impl<T: Entity> PartialEq<WeakModelHandle<T>> for ModelHandle<T> {
4422    fn eq(&self, other: &WeakModelHandle<T>) -> bool {
4423        self.model_id == other.model_id
4424    }
4425}
4426
4427impl<T: Entity> Hash for ModelHandle<T> {
4428    fn hash<H: Hasher>(&self, state: &mut H) {
4429        self.model_id.hash(state);
4430    }
4431}
4432
4433impl<T: Entity> std::borrow::Borrow<usize> for ModelHandle<T> {
4434    fn borrow(&self) -> &usize {
4435        &self.model_id
4436    }
4437}
4438
4439impl<T: Entity> Debug for ModelHandle<T> {
4440    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
4441        f.debug_tuple(&format!("ModelHandle<{}>", type_name::<T>()))
4442            .field(&self.model_id)
4443            .finish()
4444    }
4445}
4446
4447unsafe impl<T: Entity> Send for ModelHandle<T> {}
4448unsafe impl<T: Entity> Sync for ModelHandle<T> {}
4449
4450impl<T: Entity> Drop for ModelHandle<T> {
4451    fn drop(&mut self) {
4452        let mut ref_counts = self.ref_counts.lock();
4453        ref_counts.dec_model(self.model_id);
4454
4455        #[cfg(any(test, feature = "test-support"))]
4456        ref_counts
4457            .leak_detector
4458            .lock()
4459            .handle_dropped(self.model_id, self.handle_id);
4460    }
4461}
4462
4463impl<T: Entity> Handle<T> for ModelHandle<T> {
4464    type Weak = WeakModelHandle<T>;
4465
4466    fn id(&self) -> usize {
4467        self.model_id
4468    }
4469
4470    fn location(&self) -> EntityLocation {
4471        EntityLocation::Model(self.model_id)
4472    }
4473
4474    fn downgrade(&self) -> Self::Weak {
4475        self.downgrade()
4476    }
4477
4478    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
4479    where
4480        Self: Sized,
4481    {
4482        weak.upgrade(cx)
4483    }
4484}
4485
4486pub struct WeakModelHandle<T> {
4487    model_id: usize,
4488    model_type: PhantomData<T>,
4489}
4490
4491impl<T> WeakHandle for WeakModelHandle<T> {
4492    fn id(&self) -> usize {
4493        self.model_id
4494    }
4495}
4496
4497unsafe impl<T> Send for WeakModelHandle<T> {}
4498unsafe impl<T> Sync for WeakModelHandle<T> {}
4499
4500impl<T: Entity> WeakModelHandle<T> {
4501    fn new(model_id: usize) -> Self {
4502        Self {
4503            model_id,
4504            model_type: PhantomData,
4505        }
4506    }
4507
4508    pub fn id(&self) -> usize {
4509        self.model_id
4510    }
4511
4512    pub fn is_upgradable(&self, cx: &impl UpgradeModelHandle) -> bool {
4513        cx.model_handle_is_upgradable(self)
4514    }
4515
4516    pub fn upgrade(&self, cx: &impl UpgradeModelHandle) -> Option<ModelHandle<T>> {
4517        cx.upgrade_model_handle(self)
4518    }
4519}
4520
4521impl<T> Hash for WeakModelHandle<T> {
4522    fn hash<H: Hasher>(&self, state: &mut H) {
4523        self.model_id.hash(state)
4524    }
4525}
4526
4527impl<T> PartialEq for WeakModelHandle<T> {
4528    fn eq(&self, other: &Self) -> bool {
4529        self.model_id == other.model_id
4530    }
4531}
4532
4533impl<T> Eq for WeakModelHandle<T> {}
4534
4535impl<T> Clone for WeakModelHandle<T> {
4536    fn clone(&self) -> Self {
4537        Self {
4538            model_id: self.model_id,
4539            model_type: PhantomData,
4540        }
4541    }
4542}
4543
4544impl<T> Copy for WeakModelHandle<T> {}
4545
4546pub struct ViewHandle<T> {
4547    window_id: usize,
4548    view_id: usize,
4549    view_type: PhantomData<T>,
4550    ref_counts: Arc<Mutex<RefCounts>>,
4551    #[cfg(any(test, feature = "test-support"))]
4552    handle_id: usize,
4553}
4554
4555impl<T: View> ViewHandle<T> {
4556    fn new(window_id: usize, view_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
4557        ref_counts.lock().inc_view(window_id, view_id);
4558        #[cfg(any(test, feature = "test-support"))]
4559        let handle_id = ref_counts
4560            .lock()
4561            .leak_detector
4562            .lock()
4563            .handle_created(Some(type_name::<T>()), view_id);
4564
4565        Self {
4566            window_id,
4567            view_id,
4568            view_type: PhantomData,
4569            ref_counts: ref_counts.clone(),
4570
4571            #[cfg(any(test, feature = "test-support"))]
4572            handle_id,
4573        }
4574    }
4575
4576    pub fn downgrade(&self) -> WeakViewHandle<T> {
4577        WeakViewHandle::new(self.window_id, self.view_id)
4578    }
4579
4580    pub fn window_id(&self) -> usize {
4581        self.window_id
4582    }
4583
4584    pub fn id(&self) -> usize {
4585        self.view_id
4586    }
4587
4588    pub fn read<'a, C: ReadView>(&self, cx: &'a C) -> &'a T {
4589        cx.read_view(self)
4590    }
4591
4592    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
4593    where
4594        C: ReadViewWith,
4595        F: FnOnce(&T, &AppContext) -> S,
4596    {
4597        let mut read = Some(read);
4598        cx.read_view_with(self, &mut |view, cx| {
4599            let read = read.take().unwrap();
4600            read(view, cx)
4601        })
4602    }
4603
4604    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
4605    where
4606        C: UpdateView,
4607        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
4608    {
4609        let mut update = Some(update);
4610        cx.update_view(self, &mut |view, cx| {
4611            let update = update.take().unwrap();
4612            update(view, cx)
4613        })
4614    }
4615
4616    pub fn defer<C, F>(&self, cx: &mut C, update: F)
4617    where
4618        C: AsMut<MutableAppContext>,
4619        F: 'static + FnOnce(&mut T, &mut ViewContext<T>),
4620    {
4621        let this = self.clone();
4622        cx.as_mut().defer(move |cx| {
4623            this.update(cx, |view, cx| update(view, cx));
4624        });
4625    }
4626
4627    pub fn is_focused(&self, cx: &AppContext) -> bool {
4628        cx.focused_view_id(self.window_id)
4629            .map_or(false, |focused_id| focused_id == self.view_id)
4630    }
4631
4632    #[cfg(any(test, feature = "test-support"))]
4633    pub fn next_notification(&self, cx: &TestAppContext) -> impl Future<Output = ()> {
4634        use postage::prelude::{Sink as _, Stream as _};
4635
4636        let (mut tx, mut rx) = postage::mpsc::channel(1);
4637        let mut cx = cx.cx.borrow_mut();
4638        let subscription = cx.observe(self, move |_, _| {
4639            tx.try_send(()).ok();
4640        });
4641
4642        let duration = if std::env::var("CI").is_ok() {
4643            Duration::from_secs(5)
4644        } else {
4645            Duration::from_secs(1)
4646        };
4647
4648        async move {
4649            let notification = crate::util::timeout(duration, rx.recv())
4650                .await
4651                .expect("next notification timed out");
4652            drop(subscription);
4653            notification.expect("model dropped while test was waiting for its next notification")
4654        }
4655    }
4656
4657    #[cfg(any(test, feature = "test-support"))]
4658    pub fn condition(
4659        &self,
4660        cx: &TestAppContext,
4661        mut predicate: impl FnMut(&T, &AppContext) -> bool,
4662    ) -> impl Future<Output = ()> {
4663        use postage::prelude::{Sink as _, Stream as _};
4664
4665        let (tx, mut rx) = postage::mpsc::channel(1024);
4666        let timeout_duration = cx.condition_duration();
4667
4668        let mut cx = cx.cx.borrow_mut();
4669        let subscriptions = self.update(&mut *cx, |_, cx| {
4670            (
4671                cx.observe(self, {
4672                    let mut tx = tx.clone();
4673                    move |_, _, _| {
4674                        tx.blocking_send(()).ok();
4675                    }
4676                }),
4677                cx.subscribe(self, {
4678                    let mut tx = tx.clone();
4679                    move |_, _, _, _| {
4680                        tx.blocking_send(()).ok();
4681                    }
4682                }),
4683            )
4684        });
4685
4686        let cx = cx.weak_self.as_ref().unwrap().upgrade().unwrap();
4687        let handle = self.downgrade();
4688
4689        async move {
4690            crate::util::timeout(timeout_duration, async move {
4691                loop {
4692                    {
4693                        let cx = cx.borrow();
4694                        let cx = cx.as_ref();
4695                        if predicate(
4696                            handle
4697                                .upgrade(cx)
4698                                .expect("view dropped with pending condition")
4699                                .read(cx),
4700                            cx,
4701                        ) {
4702                            break;
4703                        }
4704                    }
4705
4706                    cx.borrow().foreground().start_waiting();
4707                    rx.recv()
4708                        .await
4709                        .expect("view dropped with pending condition");
4710                    cx.borrow().foreground().finish_waiting();
4711                }
4712            })
4713            .await
4714            .expect("condition timed out");
4715            drop(subscriptions);
4716        }
4717    }
4718}
4719
4720impl<T: View> Clone for ViewHandle<T> {
4721    fn clone(&self) -> Self {
4722        ViewHandle::new(self.window_id, self.view_id, &self.ref_counts)
4723    }
4724}
4725
4726impl<T> PartialEq for ViewHandle<T> {
4727    fn eq(&self, other: &Self) -> bool {
4728        self.window_id == other.window_id && self.view_id == other.view_id
4729    }
4730}
4731
4732impl<T> PartialEq<WeakViewHandle<T>> for ViewHandle<T> {
4733    fn eq(&self, other: &WeakViewHandle<T>) -> bool {
4734        self.window_id == other.window_id && self.view_id == other.view_id
4735    }
4736}
4737
4738impl<T> PartialEq<ViewHandle<T>> for WeakViewHandle<T> {
4739    fn eq(&self, other: &ViewHandle<T>) -> bool {
4740        self.window_id == other.window_id && self.view_id == other.view_id
4741    }
4742}
4743
4744impl<T> Eq for ViewHandle<T> {}
4745
4746impl<T> Hash for ViewHandle<T> {
4747    fn hash<H: Hasher>(&self, state: &mut H) {
4748        self.window_id.hash(state);
4749        self.view_id.hash(state);
4750    }
4751}
4752
4753impl<T> Debug for ViewHandle<T> {
4754    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
4755        f.debug_struct(&format!("ViewHandle<{}>", type_name::<T>()))
4756            .field("window_id", &self.window_id)
4757            .field("view_id", &self.view_id)
4758            .finish()
4759    }
4760}
4761
4762impl<T> Drop for ViewHandle<T> {
4763    fn drop(&mut self) {
4764        self.ref_counts
4765            .lock()
4766            .dec_view(self.window_id, self.view_id);
4767        #[cfg(any(test, feature = "test-support"))]
4768        self.ref_counts
4769            .lock()
4770            .leak_detector
4771            .lock()
4772            .handle_dropped(self.view_id, self.handle_id);
4773    }
4774}
4775
4776impl<T: View> Handle<T> for ViewHandle<T> {
4777    type Weak = WeakViewHandle<T>;
4778
4779    fn id(&self) -> usize {
4780        self.view_id
4781    }
4782
4783    fn location(&self) -> EntityLocation {
4784        EntityLocation::View(self.window_id, self.view_id)
4785    }
4786
4787    fn downgrade(&self) -> Self::Weak {
4788        self.downgrade()
4789    }
4790
4791    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
4792    where
4793        Self: Sized,
4794    {
4795        weak.upgrade(cx)
4796    }
4797}
4798
4799pub struct AnyViewHandle {
4800    window_id: usize,
4801    view_id: usize,
4802    view_type: TypeId,
4803    ref_counts: Arc<Mutex<RefCounts>>,
4804
4805    #[cfg(any(test, feature = "test-support"))]
4806    handle_id: usize,
4807}
4808
4809impl AnyViewHandle {
4810    fn new(
4811        window_id: usize,
4812        view_id: usize,
4813        view_type: TypeId,
4814        ref_counts: Arc<Mutex<RefCounts>>,
4815    ) -> Self {
4816        ref_counts.lock().inc_view(window_id, view_id);
4817
4818        #[cfg(any(test, feature = "test-support"))]
4819        let handle_id = ref_counts
4820            .lock()
4821            .leak_detector
4822            .lock()
4823            .handle_created(None, view_id);
4824
4825        Self {
4826            window_id,
4827            view_id,
4828            view_type,
4829            ref_counts,
4830            #[cfg(any(test, feature = "test-support"))]
4831            handle_id,
4832        }
4833    }
4834
4835    pub fn id(&self) -> usize {
4836        self.view_id
4837    }
4838
4839    pub fn is<T: 'static>(&self) -> bool {
4840        TypeId::of::<T>() == self.view_type
4841    }
4842
4843    pub fn is_focused(&self, cx: &AppContext) -> bool {
4844        cx.focused_view_id(self.window_id)
4845            .map_or(false, |focused_id| focused_id == self.view_id)
4846    }
4847
4848    pub fn downcast<T: View>(self) -> Option<ViewHandle<T>> {
4849        if self.is::<T>() {
4850            let result = Some(ViewHandle {
4851                window_id: self.window_id,
4852                view_id: self.view_id,
4853                ref_counts: self.ref_counts.clone(),
4854                view_type: PhantomData,
4855                #[cfg(any(test, feature = "test-support"))]
4856                handle_id: self.handle_id,
4857            });
4858            unsafe {
4859                Arc::decrement_strong_count(Arc::as_ptr(&self.ref_counts));
4860            }
4861            std::mem::forget(self);
4862            result
4863        } else {
4864            None
4865        }
4866    }
4867
4868    pub fn downgrade(&self) -> AnyWeakViewHandle {
4869        AnyWeakViewHandle {
4870            window_id: self.window_id,
4871            view_id: self.view_id,
4872            view_type: self.view_type,
4873        }
4874    }
4875
4876    pub fn view_type(&self) -> TypeId {
4877        self.view_type
4878    }
4879
4880    pub fn debug_json(&self, cx: &AppContext) -> serde_json::Value {
4881        cx.views
4882            .get(&(self.window_id, self.view_id))
4883            .map_or_else(|| serde_json::Value::Null, |view| view.debug_json(cx))
4884    }
4885}
4886
4887impl Clone for AnyViewHandle {
4888    fn clone(&self) -> Self {
4889        Self::new(
4890            self.window_id,
4891            self.view_id,
4892            self.view_type,
4893            self.ref_counts.clone(),
4894        )
4895    }
4896}
4897
4898impl From<&AnyViewHandle> for AnyViewHandle {
4899    fn from(handle: &AnyViewHandle) -> Self {
4900        handle.clone()
4901    }
4902}
4903
4904impl<T: View> From<&ViewHandle<T>> for AnyViewHandle {
4905    fn from(handle: &ViewHandle<T>) -> Self {
4906        Self::new(
4907            handle.window_id,
4908            handle.view_id,
4909            TypeId::of::<T>(),
4910            handle.ref_counts.clone(),
4911        )
4912    }
4913}
4914
4915impl<T: View> From<ViewHandle<T>> for AnyViewHandle {
4916    fn from(handle: ViewHandle<T>) -> Self {
4917        let any_handle = AnyViewHandle {
4918            window_id: handle.window_id,
4919            view_id: handle.view_id,
4920            view_type: TypeId::of::<T>(),
4921            ref_counts: handle.ref_counts.clone(),
4922            #[cfg(any(test, feature = "test-support"))]
4923            handle_id: handle.handle_id,
4924        };
4925
4926        unsafe {
4927            Arc::decrement_strong_count(Arc::as_ptr(&handle.ref_counts));
4928        }
4929        std::mem::forget(handle);
4930        any_handle
4931    }
4932}
4933
4934impl Drop for AnyViewHandle {
4935    fn drop(&mut self) {
4936        self.ref_counts
4937            .lock()
4938            .dec_view(self.window_id, self.view_id);
4939        #[cfg(any(test, feature = "test-support"))]
4940        self.ref_counts
4941            .lock()
4942            .leak_detector
4943            .lock()
4944            .handle_dropped(self.view_id, self.handle_id);
4945    }
4946}
4947
4948pub struct AnyModelHandle {
4949    model_id: usize,
4950    model_type: TypeId,
4951    ref_counts: Arc<Mutex<RefCounts>>,
4952
4953    #[cfg(any(test, feature = "test-support"))]
4954    handle_id: usize,
4955}
4956
4957impl AnyModelHandle {
4958    fn new(model_id: usize, model_type: TypeId, ref_counts: Arc<Mutex<RefCounts>>) -> Self {
4959        ref_counts.lock().inc_model(model_id);
4960
4961        #[cfg(any(test, feature = "test-support"))]
4962        let handle_id = ref_counts
4963            .lock()
4964            .leak_detector
4965            .lock()
4966            .handle_created(None, model_id);
4967
4968        Self {
4969            model_id,
4970            model_type,
4971            ref_counts,
4972
4973            #[cfg(any(test, feature = "test-support"))]
4974            handle_id,
4975        }
4976    }
4977
4978    pub fn downcast<T: Entity>(self) -> Option<ModelHandle<T>> {
4979        if self.is::<T>() {
4980            let result = Some(ModelHandle {
4981                model_id: self.model_id,
4982                model_type: PhantomData,
4983                ref_counts: self.ref_counts.clone(),
4984
4985                #[cfg(any(test, feature = "test-support"))]
4986                handle_id: self.handle_id,
4987            });
4988            unsafe {
4989                Arc::decrement_strong_count(Arc::as_ptr(&self.ref_counts));
4990            }
4991            std::mem::forget(self);
4992            result
4993        } else {
4994            None
4995        }
4996    }
4997
4998    pub fn downgrade(&self) -> AnyWeakModelHandle {
4999        AnyWeakModelHandle {
5000            model_id: self.model_id,
5001            model_type: self.model_type,
5002        }
5003    }
5004
5005    pub fn is<T: Entity>(&self) -> bool {
5006        self.model_type == TypeId::of::<T>()
5007    }
5008
5009    pub fn model_type(&self) -> TypeId {
5010        self.model_type
5011    }
5012}
5013
5014impl<T: Entity> From<ModelHandle<T>> for AnyModelHandle {
5015    fn from(handle: ModelHandle<T>) -> Self {
5016        Self::new(
5017            handle.model_id,
5018            TypeId::of::<T>(),
5019            handle.ref_counts.clone(),
5020        )
5021    }
5022}
5023
5024impl Clone for AnyModelHandle {
5025    fn clone(&self) -> Self {
5026        Self::new(self.model_id, self.model_type, self.ref_counts.clone())
5027    }
5028}
5029
5030impl Drop for AnyModelHandle {
5031    fn drop(&mut self) {
5032        let mut ref_counts = self.ref_counts.lock();
5033        ref_counts.dec_model(self.model_id);
5034
5035        #[cfg(any(test, feature = "test-support"))]
5036        ref_counts
5037            .leak_detector
5038            .lock()
5039            .handle_dropped(self.model_id, self.handle_id);
5040    }
5041}
5042
5043pub struct AnyWeakModelHandle {
5044    model_id: usize,
5045    model_type: TypeId,
5046}
5047
5048impl AnyWeakModelHandle {
5049    pub fn upgrade(&self, cx: &impl UpgradeModelHandle) -> Option<AnyModelHandle> {
5050        cx.upgrade_any_model_handle(self)
5051    }
5052}
5053
5054impl<T: Entity> From<WeakModelHandle<T>> for AnyWeakModelHandle {
5055    fn from(handle: WeakModelHandle<T>) -> Self {
5056        AnyWeakModelHandle {
5057            model_id: handle.model_id,
5058            model_type: TypeId::of::<T>(),
5059        }
5060    }
5061}
5062
5063pub struct WeakViewHandle<T> {
5064    window_id: usize,
5065    view_id: usize,
5066    view_type: PhantomData<T>,
5067}
5068
5069impl<T> WeakHandle for WeakViewHandle<T> {
5070    fn id(&self) -> usize {
5071        self.view_id
5072    }
5073}
5074
5075impl<T: View> WeakViewHandle<T> {
5076    fn new(window_id: usize, view_id: usize) -> Self {
5077        Self {
5078            window_id,
5079            view_id,
5080            view_type: PhantomData,
5081        }
5082    }
5083
5084    pub fn id(&self) -> usize {
5085        self.view_id
5086    }
5087
5088    pub fn window_id(&self) -> usize {
5089        self.window_id
5090    }
5091
5092    pub fn upgrade(&self, cx: &impl UpgradeViewHandle) -> Option<ViewHandle<T>> {
5093        cx.upgrade_view_handle(self)
5094    }
5095}
5096
5097impl<T> Clone for WeakViewHandle<T> {
5098    fn clone(&self) -> Self {
5099        Self {
5100            window_id: self.window_id,
5101            view_id: self.view_id,
5102            view_type: PhantomData,
5103        }
5104    }
5105}
5106
5107impl<T> PartialEq for WeakViewHandle<T> {
5108    fn eq(&self, other: &Self) -> bool {
5109        self.window_id == other.window_id && self.view_id == other.view_id
5110    }
5111}
5112
5113impl<T> Eq for WeakViewHandle<T> {}
5114
5115impl<T> Hash for WeakViewHandle<T> {
5116    fn hash<H: Hasher>(&self, state: &mut H) {
5117        self.window_id.hash(state);
5118        self.view_id.hash(state);
5119    }
5120}
5121
5122pub struct AnyWeakViewHandle {
5123    window_id: usize,
5124    view_id: usize,
5125    view_type: TypeId,
5126}
5127
5128impl AnyWeakViewHandle {
5129    pub fn upgrade(&self, cx: &impl UpgradeViewHandle) -> Option<AnyViewHandle> {
5130        cx.upgrade_any_view_handle(self)
5131    }
5132}
5133
5134impl<T: View> From<WeakViewHandle<T>> for AnyWeakViewHandle {
5135    fn from(handle: WeakViewHandle<T>) -> Self {
5136        AnyWeakViewHandle {
5137            window_id: handle.window_id,
5138            view_id: handle.view_id,
5139            view_type: TypeId::of::<T>(),
5140        }
5141    }
5142}
5143
5144#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
5145pub struct ElementStateId {
5146    view_id: usize,
5147    element_id: usize,
5148    tag: TypeId,
5149}
5150
5151pub struct ElementStateHandle<T> {
5152    value_type: PhantomData<T>,
5153    id: ElementStateId,
5154    ref_counts: Weak<Mutex<RefCounts>>,
5155}
5156
5157impl<T: 'static> ElementStateHandle<T> {
5158    fn new(id: ElementStateId, frame_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
5159        ref_counts.lock().inc_element_state(id, frame_id);
5160        Self {
5161            value_type: PhantomData,
5162            id,
5163            ref_counts: Arc::downgrade(ref_counts),
5164        }
5165    }
5166
5167    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
5168        cx.element_states
5169            .get(&self.id)
5170            .unwrap()
5171            .downcast_ref()
5172            .unwrap()
5173    }
5174
5175    pub fn update<C, R>(&self, cx: &mut C, f: impl FnOnce(&mut T, &mut C) -> R) -> R
5176    where
5177        C: DerefMut<Target = MutableAppContext>,
5178    {
5179        let mut element_state = cx.deref_mut().cx.element_states.remove(&self.id).unwrap();
5180        let result = f(element_state.downcast_mut().unwrap(), cx);
5181        cx.deref_mut()
5182            .cx
5183            .element_states
5184            .insert(self.id, element_state);
5185        result
5186    }
5187}
5188
5189impl<T> Drop for ElementStateHandle<T> {
5190    fn drop(&mut self) {
5191        if let Some(ref_counts) = self.ref_counts.upgrade() {
5192            ref_counts.lock().dec_element_state(self.id);
5193        }
5194    }
5195}
5196
5197#[must_use]
5198pub enum Subscription {
5199    Subscription {
5200        id: usize,
5201        entity_id: usize,
5202        subscriptions:
5203            Option<Weak<Mutex<HashMap<usize, BTreeMap<usize, Option<SubscriptionCallback>>>>>>,
5204    },
5205    GlobalSubscription {
5206        id: usize,
5207        type_id: TypeId,
5208        subscriptions: Option<
5209            Weak<Mutex<HashMap<TypeId, BTreeMap<usize, Option<GlobalSubscriptionCallback>>>>>,
5210        >,
5211    },
5212    Observation {
5213        id: usize,
5214        entity_id: usize,
5215        observations:
5216            Option<Weak<Mutex<HashMap<usize, BTreeMap<usize, Option<ObservationCallback>>>>>>,
5217    },
5218    GlobalObservation {
5219        id: usize,
5220        type_id: TypeId,
5221        observations: Option<
5222            Weak<Mutex<HashMap<TypeId, BTreeMap<usize, Option<GlobalObservationCallback>>>>>,
5223        >,
5224    },
5225    FocusObservation {
5226        id: usize,
5227        view_id: usize,
5228        observations:
5229            Option<Weak<Mutex<HashMap<usize, BTreeMap<usize, Option<FocusObservationCallback>>>>>>,
5230    },
5231    ReleaseObservation {
5232        id: usize,
5233        entity_id: usize,
5234        observations:
5235            Option<Weak<Mutex<HashMap<usize, BTreeMap<usize, ReleaseObservationCallback>>>>>,
5236    },
5237    ActionObservation {
5238        id: usize,
5239        observations: Option<Weak<Mutex<BTreeMap<usize, ActionObservationCallback>>>>,
5240    },
5241    WindowActivationObservation {
5242        id: usize,
5243        window_id: usize,
5244        observations:
5245            Option<Weak<Mutex<HashMap<usize, BTreeMap<usize, Option<WindowActivationCallback>>>>>>,
5246    },
5247}
5248
5249impl Subscription {
5250    pub fn detach(&mut self) {
5251        match self {
5252            Subscription::Subscription { subscriptions, .. } => {
5253                subscriptions.take();
5254            }
5255            Subscription::GlobalSubscription { subscriptions, .. } => {
5256                subscriptions.take();
5257            }
5258            Subscription::Observation { observations, .. } => {
5259                observations.take();
5260            }
5261            Subscription::GlobalObservation { observations, .. } => {
5262                observations.take();
5263            }
5264            Subscription::ReleaseObservation { observations, .. } => {
5265                observations.take();
5266            }
5267            Subscription::FocusObservation { observations, .. } => {
5268                observations.take();
5269            }
5270            Subscription::ActionObservation { observations, .. } => {
5271                observations.take();
5272            }
5273            Subscription::WindowActivationObservation { observations, .. } => {
5274                observations.take();
5275            }
5276        }
5277    }
5278}
5279
5280impl Drop for Subscription {
5281    fn drop(&mut self) {
5282        match self {
5283            Subscription::Subscription {
5284                id,
5285                entity_id,
5286                subscriptions,
5287            } => {
5288                if let Some(subscriptions) = subscriptions.as_ref().and_then(Weak::upgrade) {
5289                    match subscriptions
5290                        .lock()
5291                        .entry(*entity_id)
5292                        .or_default()
5293                        .entry(*id)
5294                    {
5295                        btree_map::Entry::Vacant(entry) => {
5296                            entry.insert(None);
5297                        }
5298                        btree_map::Entry::Occupied(entry) => {
5299                            entry.remove();
5300                        }
5301                    }
5302                }
5303            }
5304            Subscription::GlobalSubscription {
5305                id,
5306                type_id,
5307                subscriptions,
5308            } => {
5309                if let Some(subscriptions) = subscriptions.as_ref().and_then(Weak::upgrade) {
5310                    match subscriptions.lock().entry(*type_id).or_default().entry(*id) {
5311                        btree_map::Entry::Vacant(entry) => {
5312                            entry.insert(None);
5313                        }
5314                        btree_map::Entry::Occupied(entry) => {
5315                            entry.remove();
5316                        }
5317                    }
5318                }
5319            }
5320            Subscription::Observation {
5321                id,
5322                entity_id,
5323                observations,
5324            } => {
5325                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5326                    match observations
5327                        .lock()
5328                        .entry(*entity_id)
5329                        .or_default()
5330                        .entry(*id)
5331                    {
5332                        btree_map::Entry::Vacant(entry) => {
5333                            entry.insert(None);
5334                        }
5335                        btree_map::Entry::Occupied(entry) => {
5336                            entry.remove();
5337                        }
5338                    }
5339                }
5340            }
5341            Subscription::GlobalObservation {
5342                id,
5343                type_id,
5344                observations,
5345            } => {
5346                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5347                    match observations.lock().entry(*type_id).or_default().entry(*id) {
5348                        collections::btree_map::Entry::Vacant(entry) => {
5349                            entry.insert(None);
5350                        }
5351                        collections::btree_map::Entry::Occupied(entry) => {
5352                            entry.remove();
5353                        }
5354                    }
5355                }
5356            }
5357            Subscription::ReleaseObservation {
5358                id,
5359                entity_id,
5360                observations,
5361            } => {
5362                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5363                    if let Some(observations) = observations.lock().get_mut(entity_id) {
5364                        observations.remove(id);
5365                    }
5366                }
5367            }
5368            Subscription::FocusObservation {
5369                id,
5370                view_id,
5371                observations,
5372            } => {
5373                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5374                    match observations.lock().entry(*view_id).or_default().entry(*id) {
5375                        btree_map::Entry::Vacant(entry) => {
5376                            entry.insert(None);
5377                        }
5378                        btree_map::Entry::Occupied(entry) => {
5379                            entry.remove();
5380                        }
5381                    }
5382                }
5383            }
5384            Subscription::ActionObservation { id, observations } => {
5385                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5386                    observations.lock().remove(&id);
5387                }
5388            }
5389            Subscription::WindowActivationObservation {
5390                id,
5391                window_id,
5392                observations,
5393            } => {
5394                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5395                    match observations
5396                        .lock()
5397                        .entry(*window_id)
5398                        .or_default()
5399                        .entry(*id)
5400                    {
5401                        btree_map::Entry::Vacant(entry) => {
5402                            entry.insert(None);
5403                        }
5404                        btree_map::Entry::Occupied(entry) => {
5405                            entry.remove();
5406                        }
5407                    }
5408                }
5409            }
5410        }
5411    }
5412}
5413
5414lazy_static! {
5415    static ref LEAK_BACKTRACE: bool =
5416        std::env::var("LEAK_BACKTRACE").map_or(false, |b| !b.is_empty());
5417}
5418
5419#[cfg(any(test, feature = "test-support"))]
5420#[derive(Default)]
5421pub struct LeakDetector {
5422    next_handle_id: usize,
5423    handle_backtraces: HashMap<
5424        usize,
5425        (
5426            Option<&'static str>,
5427            HashMap<usize, Option<backtrace::Backtrace>>,
5428        ),
5429    >,
5430}
5431
5432#[cfg(any(test, feature = "test-support"))]
5433impl LeakDetector {
5434    fn handle_created(&mut self, type_name: Option<&'static str>, entity_id: usize) -> usize {
5435        let handle_id = post_inc(&mut self.next_handle_id);
5436        let entry = self.handle_backtraces.entry(entity_id).or_default();
5437        let backtrace = if *LEAK_BACKTRACE {
5438            Some(backtrace::Backtrace::new_unresolved())
5439        } else {
5440            None
5441        };
5442        if let Some(type_name) = type_name {
5443            entry.0.get_or_insert(type_name);
5444        }
5445        entry.1.insert(handle_id, backtrace);
5446        handle_id
5447    }
5448
5449    fn handle_dropped(&mut self, entity_id: usize, handle_id: usize) {
5450        if let Some((_, backtraces)) = self.handle_backtraces.get_mut(&entity_id) {
5451            assert!(backtraces.remove(&handle_id).is_some());
5452            if backtraces.is_empty() {
5453                self.handle_backtraces.remove(&entity_id);
5454            }
5455        }
5456    }
5457
5458    pub fn assert_dropped(&mut self, entity_id: usize) {
5459        if let Some((type_name, backtraces)) = self.handle_backtraces.get_mut(&entity_id) {
5460            for trace in backtraces.values_mut() {
5461                if let Some(trace) = trace {
5462                    trace.resolve();
5463                    eprintln!("{:?}", crate::util::CwdBacktrace(trace));
5464                }
5465            }
5466
5467            let hint = if *LEAK_BACKTRACE {
5468                ""
5469            } else {
5470                " – set LEAK_BACKTRACE=1 for more information"
5471            };
5472
5473            panic!(
5474                "{} handles to {} {} still exist{}",
5475                backtraces.len(),
5476                type_name.unwrap_or("entity"),
5477                entity_id,
5478                hint
5479            );
5480        }
5481    }
5482
5483    pub fn detect(&mut self) {
5484        let mut found_leaks = false;
5485        for (id, (type_name, backtraces)) in self.handle_backtraces.iter_mut() {
5486            eprintln!(
5487                "leaked {} handles to {} {}",
5488                backtraces.len(),
5489                type_name.unwrap_or("entity"),
5490                id
5491            );
5492            for trace in backtraces.values_mut() {
5493                if let Some(trace) = trace {
5494                    trace.resolve();
5495                    eprintln!("{:?}", crate::util::CwdBacktrace(trace));
5496                }
5497            }
5498            found_leaks = true;
5499        }
5500
5501        let hint = if *LEAK_BACKTRACE {
5502            ""
5503        } else {
5504            " – set LEAK_BACKTRACE=1 for more information"
5505        };
5506        assert!(!found_leaks, "detected leaked handles{}", hint);
5507    }
5508}
5509
5510#[derive(Default)]
5511struct RefCounts {
5512    entity_counts: HashMap<usize, usize>,
5513    element_state_counts: HashMap<ElementStateId, ElementStateRefCount>,
5514    dropped_models: HashSet<usize>,
5515    dropped_views: HashSet<(usize, usize)>,
5516    dropped_element_states: HashSet<ElementStateId>,
5517
5518    #[cfg(any(test, feature = "test-support"))]
5519    leak_detector: Arc<Mutex<LeakDetector>>,
5520}
5521
5522struct ElementStateRefCount {
5523    ref_count: usize,
5524    frame_id: usize,
5525}
5526
5527impl RefCounts {
5528    fn inc_model(&mut self, model_id: usize) {
5529        match self.entity_counts.entry(model_id) {
5530            Entry::Occupied(mut entry) => {
5531                *entry.get_mut() += 1;
5532            }
5533            Entry::Vacant(entry) => {
5534                entry.insert(1);
5535                self.dropped_models.remove(&model_id);
5536            }
5537        }
5538    }
5539
5540    fn inc_view(&mut self, window_id: usize, view_id: usize) {
5541        match self.entity_counts.entry(view_id) {
5542            Entry::Occupied(mut entry) => *entry.get_mut() += 1,
5543            Entry::Vacant(entry) => {
5544                entry.insert(1);
5545                self.dropped_views.remove(&(window_id, view_id));
5546            }
5547        }
5548    }
5549
5550    fn inc_element_state(&mut self, id: ElementStateId, frame_id: usize) {
5551        match self.element_state_counts.entry(id) {
5552            Entry::Occupied(mut entry) => {
5553                let entry = entry.get_mut();
5554                if entry.frame_id == frame_id || entry.ref_count >= 2 {
5555                    panic!("used the same element state more than once in the same frame");
5556                }
5557                entry.ref_count += 1;
5558                entry.frame_id = frame_id;
5559            }
5560            Entry::Vacant(entry) => {
5561                entry.insert(ElementStateRefCount {
5562                    ref_count: 1,
5563                    frame_id,
5564                });
5565                self.dropped_element_states.remove(&id);
5566            }
5567        }
5568    }
5569
5570    fn dec_model(&mut self, model_id: usize) {
5571        let count = self.entity_counts.get_mut(&model_id).unwrap();
5572        *count -= 1;
5573        if *count == 0 {
5574            self.entity_counts.remove(&model_id);
5575            self.dropped_models.insert(model_id);
5576        }
5577    }
5578
5579    fn dec_view(&mut self, window_id: usize, view_id: usize) {
5580        let count = self.entity_counts.get_mut(&view_id).unwrap();
5581        *count -= 1;
5582        if *count == 0 {
5583            self.entity_counts.remove(&view_id);
5584            self.dropped_views.insert((window_id, view_id));
5585        }
5586    }
5587
5588    fn dec_element_state(&mut self, id: ElementStateId) {
5589        let entry = self.element_state_counts.get_mut(&id).unwrap();
5590        entry.ref_count -= 1;
5591        if entry.ref_count == 0 {
5592            self.element_state_counts.remove(&id);
5593            self.dropped_element_states.insert(id);
5594        }
5595    }
5596
5597    fn is_entity_alive(&self, entity_id: usize) -> bool {
5598        self.entity_counts.contains_key(&entity_id)
5599    }
5600
5601    fn take_dropped(
5602        &mut self,
5603    ) -> (
5604        HashSet<usize>,
5605        HashSet<(usize, usize)>,
5606        HashSet<ElementStateId>,
5607    ) {
5608        (
5609            std::mem::take(&mut self.dropped_models),
5610            std::mem::take(&mut self.dropped_views),
5611            std::mem::take(&mut self.dropped_element_states),
5612        )
5613    }
5614}
5615
5616#[cfg(test)]
5617mod tests {
5618    use super::*;
5619    use crate::{actions, elements::*, impl_actions, MouseButton, MouseButtonEvent};
5620    use serde::Deserialize;
5621    use smol::future::poll_once;
5622    use std::{
5623        cell::Cell,
5624        sync::atomic::{AtomicBool, AtomicUsize, Ordering::SeqCst},
5625    };
5626
5627    #[crate::test(self)]
5628    fn test_model_handles(cx: &mut MutableAppContext) {
5629        struct Model {
5630            other: Option<ModelHandle<Model>>,
5631            events: Vec<String>,
5632        }
5633
5634        impl Entity for Model {
5635            type Event = usize;
5636        }
5637
5638        impl Model {
5639            fn new(other: Option<ModelHandle<Self>>, cx: &mut ModelContext<Self>) -> Self {
5640                if let Some(other) = other.as_ref() {
5641                    cx.observe(other, |me, _, _| {
5642                        me.events.push("notified".into());
5643                    })
5644                    .detach();
5645                    cx.subscribe(other, |me, _, event, _| {
5646                        me.events.push(format!("observed event {}", event));
5647                    })
5648                    .detach();
5649                }
5650
5651                Self {
5652                    other,
5653                    events: Vec::new(),
5654                }
5655            }
5656        }
5657
5658        let handle_1 = cx.add_model(|cx| Model::new(None, cx));
5659        let handle_2 = cx.add_model(|cx| Model::new(Some(handle_1.clone()), cx));
5660        assert_eq!(cx.cx.models.len(), 2);
5661
5662        handle_1.update(cx, |model, cx| {
5663            model.events.push("updated".into());
5664            cx.emit(1);
5665            cx.notify();
5666            cx.emit(2);
5667        });
5668        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
5669        assert_eq!(
5670            handle_2.read(cx).events,
5671            vec![
5672                "observed event 1".to_string(),
5673                "notified".to_string(),
5674                "observed event 2".to_string(),
5675            ]
5676        );
5677
5678        handle_2.update(cx, |model, _| {
5679            drop(handle_1);
5680            model.other.take();
5681        });
5682
5683        assert_eq!(cx.cx.models.len(), 1);
5684        assert!(cx.subscriptions.lock().is_empty());
5685        assert!(cx.observations.lock().is_empty());
5686    }
5687
5688    #[crate::test(self)]
5689    fn test_model_events(cx: &mut MutableAppContext) {
5690        #[derive(Default)]
5691        struct Model {
5692            events: Vec<usize>,
5693        }
5694
5695        impl Entity for Model {
5696            type Event = usize;
5697        }
5698
5699        let handle_1 = cx.add_model(|_| Model::default());
5700        let handle_2 = cx.add_model(|_| Model::default());
5701
5702        handle_1.update(cx, |_, cx| {
5703            cx.subscribe(&handle_2, move |model: &mut Model, emitter, event, cx| {
5704                model.events.push(*event);
5705
5706                cx.subscribe(&emitter, |model, _, event, _| {
5707                    model.events.push(*event * 2);
5708                })
5709                .detach();
5710            })
5711            .detach();
5712        });
5713
5714        handle_2.update(cx, |_, c| c.emit(7));
5715        assert_eq!(handle_1.read(cx).events, vec![7]);
5716
5717        handle_2.update(cx, |_, c| c.emit(5));
5718        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10]);
5719    }
5720
5721    #[crate::test(self)]
5722    fn test_model_emit_before_subscribe_in_same_update_cycle(cx: &mut MutableAppContext) {
5723        #[derive(Default)]
5724        struct Model;
5725
5726        impl Entity for Model {
5727            type Event = ();
5728        }
5729
5730        let events = Rc::new(RefCell::new(Vec::new()));
5731        cx.add_model(|cx| {
5732            drop(cx.subscribe(&cx.handle(), {
5733                let events = events.clone();
5734                move |_, _, _, _| events.borrow_mut().push("dropped before flush")
5735            }));
5736            cx.subscribe(&cx.handle(), {
5737                let events = events.clone();
5738                move |_, _, _, _| events.borrow_mut().push("before emit")
5739            })
5740            .detach();
5741            cx.emit(());
5742            cx.subscribe(&cx.handle(), {
5743                let events = events.clone();
5744                move |_, _, _, _| events.borrow_mut().push("after emit")
5745            })
5746            .detach();
5747            Model
5748        });
5749        assert_eq!(*events.borrow(), ["before emit"]);
5750    }
5751
5752    #[crate::test(self)]
5753    fn test_observe_and_notify_from_model(cx: &mut MutableAppContext) {
5754        #[derive(Default)]
5755        struct Model {
5756            count: usize,
5757            events: Vec<usize>,
5758        }
5759
5760        impl Entity for Model {
5761            type Event = ();
5762        }
5763
5764        let handle_1 = cx.add_model(|_| Model::default());
5765        let handle_2 = cx.add_model(|_| Model::default());
5766
5767        handle_1.update(cx, |_, c| {
5768            c.observe(&handle_2, move |model, observed, c| {
5769                model.events.push(observed.read(c).count);
5770                c.observe(&observed, |model, observed, c| {
5771                    model.events.push(observed.read(c).count * 2);
5772                })
5773                .detach();
5774            })
5775            .detach();
5776        });
5777
5778        handle_2.update(cx, |model, c| {
5779            model.count = 7;
5780            c.notify()
5781        });
5782        assert_eq!(handle_1.read(cx).events, vec![7]);
5783
5784        handle_2.update(cx, |model, c| {
5785            model.count = 5;
5786            c.notify()
5787        });
5788        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10])
5789    }
5790
5791    #[crate::test(self)]
5792    fn test_model_notify_before_observe_in_same_update_cycle(cx: &mut MutableAppContext) {
5793        #[derive(Default)]
5794        struct Model;
5795
5796        impl Entity for Model {
5797            type Event = ();
5798        }
5799
5800        let events = Rc::new(RefCell::new(Vec::new()));
5801        cx.add_model(|cx| {
5802            drop(cx.observe(&cx.handle(), {
5803                let events = events.clone();
5804                move |_, _, _| events.borrow_mut().push("dropped before flush")
5805            }));
5806            cx.observe(&cx.handle(), {
5807                let events = events.clone();
5808                move |_, _, _| events.borrow_mut().push("before notify")
5809            })
5810            .detach();
5811            cx.notify();
5812            cx.observe(&cx.handle(), {
5813                let events = events.clone();
5814                move |_, _, _| events.borrow_mut().push("after notify")
5815            })
5816            .detach();
5817            Model
5818        });
5819        assert_eq!(*events.borrow(), ["before notify"]);
5820    }
5821
5822    #[crate::test(self)]
5823    fn test_defer_and_after_window_update(cx: &mut MutableAppContext) {
5824        struct View {
5825            render_count: usize,
5826        }
5827
5828        impl Entity for View {
5829            type Event = usize;
5830        }
5831
5832        impl super::View for View {
5833            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
5834                post_inc(&mut self.render_count);
5835                Empty::new().boxed()
5836            }
5837
5838            fn ui_name() -> &'static str {
5839                "View"
5840            }
5841        }
5842
5843        let (_, view) = cx.add_window(Default::default(), |_| View { render_count: 0 });
5844        let called_defer = Rc::new(AtomicBool::new(false));
5845        let called_after_window_update = Rc::new(AtomicBool::new(false));
5846
5847        view.update(cx, |this, cx| {
5848            assert_eq!(this.render_count, 1);
5849            cx.defer({
5850                let called_defer = called_defer.clone();
5851                move |this, _| {
5852                    assert_eq!(this.render_count, 1);
5853                    called_defer.store(true, SeqCst);
5854                }
5855            });
5856            cx.after_window_update({
5857                let called_after_window_update = called_after_window_update.clone();
5858                move |this, cx| {
5859                    assert_eq!(this.render_count, 2);
5860                    called_after_window_update.store(true, SeqCst);
5861                    cx.notify();
5862                }
5863            });
5864            assert!(!called_defer.load(SeqCst));
5865            assert!(!called_after_window_update.load(SeqCst));
5866            cx.notify();
5867        });
5868
5869        assert!(called_defer.load(SeqCst));
5870        assert!(called_after_window_update.load(SeqCst));
5871        assert_eq!(view.read(cx).render_count, 3);
5872    }
5873
5874    #[crate::test(self)]
5875    fn test_view_handles(cx: &mut MutableAppContext) {
5876        struct View {
5877            other: Option<ViewHandle<View>>,
5878            events: Vec<String>,
5879        }
5880
5881        impl Entity for View {
5882            type Event = usize;
5883        }
5884
5885        impl super::View for View {
5886            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
5887                Empty::new().boxed()
5888            }
5889
5890            fn ui_name() -> &'static str {
5891                "View"
5892            }
5893        }
5894
5895        impl View {
5896            fn new(other: Option<ViewHandle<View>>, cx: &mut ViewContext<Self>) -> Self {
5897                if let Some(other) = other.as_ref() {
5898                    cx.subscribe(other, |me, _, event, _| {
5899                        me.events.push(format!("observed event {}", event));
5900                    })
5901                    .detach();
5902                }
5903                Self {
5904                    other,
5905                    events: Vec::new(),
5906                }
5907            }
5908        }
5909
5910        let (window_id, _) = cx.add_window(Default::default(), |cx| View::new(None, cx));
5911        let handle_1 = cx.add_view(window_id, |cx| View::new(None, cx));
5912        let handle_2 = cx.add_view(window_id, |cx| View::new(Some(handle_1.clone()), cx));
5913        assert_eq!(cx.cx.views.len(), 3);
5914
5915        handle_1.update(cx, |view, cx| {
5916            view.events.push("updated".into());
5917            cx.emit(1);
5918            cx.emit(2);
5919        });
5920        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
5921        assert_eq!(
5922            handle_2.read(cx).events,
5923            vec![
5924                "observed event 1".to_string(),
5925                "observed event 2".to_string(),
5926            ]
5927        );
5928
5929        handle_2.update(cx, |view, _| {
5930            drop(handle_1);
5931            view.other.take();
5932        });
5933
5934        assert_eq!(cx.cx.views.len(), 2);
5935        assert!(cx.subscriptions.lock().is_empty());
5936        assert!(cx.observations.lock().is_empty());
5937    }
5938
5939    #[crate::test(self)]
5940    fn test_add_window(cx: &mut MutableAppContext) {
5941        struct View {
5942            mouse_down_count: Arc<AtomicUsize>,
5943        }
5944
5945        impl Entity for View {
5946            type Event = ();
5947        }
5948
5949        impl super::View for View {
5950            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
5951                let mouse_down_count = self.mouse_down_count.clone();
5952                EventHandler::new(Empty::new().boxed())
5953                    .on_mouse_down(move |_| {
5954                        mouse_down_count.fetch_add(1, SeqCst);
5955                        true
5956                    })
5957                    .boxed()
5958            }
5959
5960            fn ui_name() -> &'static str {
5961                "View"
5962            }
5963        }
5964
5965        let mouse_down_count = Arc::new(AtomicUsize::new(0));
5966        let (window_id, _) = cx.add_window(Default::default(), |_| View {
5967            mouse_down_count: mouse_down_count.clone(),
5968        });
5969        let presenter = cx.presenters_and_platform_windows[&window_id].0.clone();
5970        // Ensure window's root element is in a valid lifecycle state.
5971        presenter.borrow_mut().dispatch_event(
5972            Event::MouseDown(MouseButtonEvent {
5973                position: Default::default(),
5974                button: MouseButton::Left,
5975                ctrl: false,
5976                alt: false,
5977                shift: false,
5978                cmd: false,
5979                click_count: 1,
5980            }),
5981            cx,
5982        );
5983        assert_eq!(mouse_down_count.load(SeqCst), 1);
5984    }
5985
5986    #[crate::test(self)]
5987    fn test_entity_release_hooks(cx: &mut MutableAppContext) {
5988        struct Model {
5989            released: Rc<Cell<bool>>,
5990        }
5991
5992        struct View {
5993            released: Rc<Cell<bool>>,
5994        }
5995
5996        impl Entity for Model {
5997            type Event = ();
5998
5999            fn release(&mut self, _: &mut MutableAppContext) {
6000                self.released.set(true);
6001            }
6002        }
6003
6004        impl Entity for View {
6005            type Event = ();
6006
6007            fn release(&mut self, _: &mut MutableAppContext) {
6008                self.released.set(true);
6009            }
6010        }
6011
6012        impl super::View for View {
6013            fn ui_name() -> &'static str {
6014                "View"
6015            }
6016
6017            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6018                Empty::new().boxed()
6019            }
6020        }
6021
6022        let model_released = Rc::new(Cell::new(false));
6023        let model_release_observed = Rc::new(Cell::new(false));
6024        let view_released = Rc::new(Cell::new(false));
6025        let view_release_observed = Rc::new(Cell::new(false));
6026
6027        let model = cx.add_model(|_| Model {
6028            released: model_released.clone(),
6029        });
6030        let (window_id, view) = cx.add_window(Default::default(), |_| View {
6031            released: view_released.clone(),
6032        });
6033        assert!(!model_released.get());
6034        assert!(!view_released.get());
6035
6036        cx.observe_release(&model, {
6037            let model_release_observed = model_release_observed.clone();
6038            move |_, _| model_release_observed.set(true)
6039        })
6040        .detach();
6041        cx.observe_release(&view, {
6042            let view_release_observed = view_release_observed.clone();
6043            move |_, _| view_release_observed.set(true)
6044        })
6045        .detach();
6046
6047        cx.update(move |_| {
6048            drop(model);
6049        });
6050        assert!(model_released.get());
6051        assert!(model_release_observed.get());
6052
6053        drop(view);
6054        cx.remove_window(window_id);
6055        assert!(view_released.get());
6056        assert!(view_release_observed.get());
6057    }
6058
6059    #[crate::test(self)]
6060    fn test_view_events(cx: &mut MutableAppContext) {
6061        #[derive(Default)]
6062        struct View {
6063            events: Vec<usize>,
6064        }
6065
6066        impl Entity for View {
6067            type Event = usize;
6068        }
6069
6070        impl super::View for View {
6071            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6072                Empty::new().boxed()
6073            }
6074
6075            fn ui_name() -> &'static str {
6076                "View"
6077            }
6078        }
6079
6080        struct Model;
6081
6082        impl Entity for Model {
6083            type Event = usize;
6084        }
6085
6086        let (window_id, handle_1) = cx.add_window(Default::default(), |_| View::default());
6087        let handle_2 = cx.add_view(window_id, |_| View::default());
6088        let handle_3 = cx.add_model(|_| Model);
6089
6090        handle_1.update(cx, |_, cx| {
6091            cx.subscribe(&handle_2, move |me, emitter, event, cx| {
6092                me.events.push(*event);
6093
6094                cx.subscribe(&emitter, |me, _, event, _| {
6095                    me.events.push(*event * 2);
6096                })
6097                .detach();
6098            })
6099            .detach();
6100
6101            cx.subscribe(&handle_3, |me, _, event, _| {
6102                me.events.push(*event);
6103            })
6104            .detach();
6105        });
6106
6107        handle_2.update(cx, |_, c| c.emit(7));
6108        assert_eq!(handle_1.read(cx).events, vec![7]);
6109
6110        handle_2.update(cx, |_, c| c.emit(5));
6111        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10]);
6112
6113        handle_3.update(cx, |_, c| c.emit(9));
6114        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10, 9]);
6115    }
6116
6117    #[crate::test(self)]
6118    fn test_global_events(cx: &mut MutableAppContext) {
6119        #[derive(Clone, Debug, Eq, PartialEq)]
6120        struct GlobalEvent(u64);
6121
6122        let events = Rc::new(RefCell::new(Vec::new()));
6123        let first_subscription;
6124        let second_subscription;
6125
6126        {
6127            let events = events.clone();
6128            first_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
6129                events.borrow_mut().push(("First", e.clone()));
6130            });
6131        }
6132
6133        {
6134            let events = events.clone();
6135            second_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
6136                events.borrow_mut().push(("Second", e.clone()));
6137            });
6138        }
6139
6140        cx.update(|cx| {
6141            cx.emit_global(GlobalEvent(1));
6142            cx.emit_global(GlobalEvent(2));
6143        });
6144
6145        drop(first_subscription);
6146
6147        cx.update(|cx| {
6148            cx.emit_global(GlobalEvent(3));
6149        });
6150
6151        drop(second_subscription);
6152
6153        cx.update(|cx| {
6154            cx.emit_global(GlobalEvent(4));
6155        });
6156
6157        assert_eq!(
6158            &*events.borrow(),
6159            &[
6160                ("First", GlobalEvent(1)),
6161                ("Second", GlobalEvent(1)),
6162                ("First", GlobalEvent(2)),
6163                ("Second", GlobalEvent(2)),
6164                ("Second", GlobalEvent(3)),
6165            ]
6166        );
6167    }
6168
6169    #[crate::test(self)]
6170    fn test_global_events_emitted_before_subscription_in_same_update_cycle(
6171        cx: &mut MutableAppContext,
6172    ) {
6173        let events = Rc::new(RefCell::new(Vec::new()));
6174        cx.update(|cx| {
6175            {
6176                let events = events.clone();
6177                drop(cx.subscribe_global(move |_: &(), _| {
6178                    events.borrow_mut().push("dropped before emit");
6179                }));
6180            }
6181
6182            {
6183                let events = events.clone();
6184                cx.subscribe_global(move |_: &(), _| {
6185                    events.borrow_mut().push("before emit");
6186                })
6187                .detach();
6188            }
6189
6190            cx.emit_global(());
6191
6192            {
6193                let events = events.clone();
6194                cx.subscribe_global(move |_: &(), _| {
6195                    events.borrow_mut().push("after emit");
6196                })
6197                .detach();
6198            }
6199        });
6200
6201        assert_eq!(*events.borrow(), ["before emit"]);
6202    }
6203
6204    #[crate::test(self)]
6205    fn test_global_nested_events(cx: &mut MutableAppContext) {
6206        #[derive(Clone, Debug, Eq, PartialEq)]
6207        struct GlobalEvent(u64);
6208
6209        let events = Rc::new(RefCell::new(Vec::new()));
6210
6211        {
6212            let events = events.clone();
6213            cx.subscribe_global(move |e: &GlobalEvent, cx| {
6214                events.borrow_mut().push(("Outer", e.clone()));
6215
6216                if e.0 == 1 {
6217                    let events = events.clone();
6218                    cx.subscribe_global(move |e: &GlobalEvent, _| {
6219                        events.borrow_mut().push(("Inner", e.clone()));
6220                    })
6221                    .detach();
6222                }
6223            })
6224            .detach();
6225        }
6226
6227        cx.update(|cx| {
6228            cx.emit_global(GlobalEvent(1));
6229            cx.emit_global(GlobalEvent(2));
6230            cx.emit_global(GlobalEvent(3));
6231        });
6232        cx.update(|cx| {
6233            cx.emit_global(GlobalEvent(4));
6234        });
6235
6236        assert_eq!(
6237            &*events.borrow(),
6238            &[
6239                ("Outer", GlobalEvent(1)),
6240                ("Outer", GlobalEvent(2)),
6241                ("Outer", GlobalEvent(3)),
6242                ("Outer", GlobalEvent(4)),
6243                ("Inner", GlobalEvent(4)),
6244            ]
6245        );
6246    }
6247
6248    #[crate::test(self)]
6249    fn test_global(cx: &mut MutableAppContext) {
6250        type Global = usize;
6251
6252        let observation_count = Rc::new(RefCell::new(0));
6253        let subscription = cx.observe_global::<Global, _>({
6254            let observation_count = observation_count.clone();
6255            move |_| {
6256                *observation_count.borrow_mut() += 1;
6257            }
6258        });
6259
6260        assert!(!cx.has_global::<Global>());
6261        assert_eq!(cx.default_global::<Global>(), &0);
6262        assert_eq!(*observation_count.borrow(), 1);
6263        assert!(cx.has_global::<Global>());
6264        assert_eq!(
6265            cx.update_global::<Global, _, _>(|global, _| {
6266                *global = 1;
6267                "Update Result"
6268            }),
6269            "Update Result"
6270        );
6271        assert_eq!(*observation_count.borrow(), 2);
6272        assert_eq!(cx.global::<Global>(), &1);
6273
6274        drop(subscription);
6275        cx.update_global::<Global, _, _>(|global, _| {
6276            *global = 2;
6277        });
6278        assert_eq!(*observation_count.borrow(), 2);
6279
6280        type OtherGlobal = f32;
6281
6282        let observation_count = Rc::new(RefCell::new(0));
6283        cx.observe_global::<OtherGlobal, _>({
6284            let observation_count = observation_count.clone();
6285            move |_| {
6286                *observation_count.borrow_mut() += 1;
6287            }
6288        })
6289        .detach();
6290
6291        assert_eq!(
6292            cx.update_default_global::<OtherGlobal, _, _>(|global, _| {
6293                assert_eq!(global, &0.0);
6294                *global = 2.0;
6295                "Default update result"
6296            }),
6297            "Default update result"
6298        );
6299        assert_eq!(cx.global::<OtherGlobal>(), &2.0);
6300        assert_eq!(*observation_count.borrow(), 1);
6301    }
6302
6303    #[crate::test(self)]
6304    fn test_dropping_subscribers(cx: &mut MutableAppContext) {
6305        struct View;
6306
6307        impl Entity for View {
6308            type Event = ();
6309        }
6310
6311        impl super::View for View {
6312            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6313                Empty::new().boxed()
6314            }
6315
6316            fn ui_name() -> &'static str {
6317                "View"
6318            }
6319        }
6320
6321        struct Model;
6322
6323        impl Entity for Model {
6324            type Event = ();
6325        }
6326
6327        let (window_id, _) = cx.add_window(Default::default(), |_| View);
6328        let observing_view = cx.add_view(window_id, |_| View);
6329        let emitting_view = cx.add_view(window_id, |_| View);
6330        let observing_model = cx.add_model(|_| Model);
6331        let observed_model = cx.add_model(|_| Model);
6332
6333        observing_view.update(cx, |_, cx| {
6334            cx.subscribe(&emitting_view, |_, _, _, _| {}).detach();
6335            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
6336        });
6337        observing_model.update(cx, |_, cx| {
6338            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
6339        });
6340
6341        cx.update(|_| {
6342            drop(observing_view);
6343            drop(observing_model);
6344        });
6345
6346        emitting_view.update(cx, |_, cx| cx.emit(()));
6347        observed_model.update(cx, |_, cx| cx.emit(()));
6348    }
6349
6350    #[crate::test(self)]
6351    fn test_view_emit_before_subscribe_in_same_update_cycle(cx: &mut MutableAppContext) {
6352        #[derive(Default)]
6353        struct TestView;
6354
6355        impl Entity for TestView {
6356            type Event = ();
6357        }
6358
6359        impl View for TestView {
6360            fn ui_name() -> &'static str {
6361                "TestView"
6362            }
6363
6364            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6365                Empty::new().boxed()
6366            }
6367        }
6368
6369        let events = Rc::new(RefCell::new(Vec::new()));
6370        cx.add_window(Default::default(), |cx| {
6371            drop(cx.subscribe(&cx.handle(), {
6372                let events = events.clone();
6373                move |_, _, _, _| events.borrow_mut().push("dropped before flush")
6374            }));
6375            cx.subscribe(&cx.handle(), {
6376                let events = events.clone();
6377                move |_, _, _, _| events.borrow_mut().push("before emit")
6378            })
6379            .detach();
6380            cx.emit(());
6381            cx.subscribe(&cx.handle(), {
6382                let events = events.clone();
6383                move |_, _, _, _| events.borrow_mut().push("after emit")
6384            })
6385            .detach();
6386            TestView
6387        });
6388        assert_eq!(*events.borrow(), ["before emit"]);
6389    }
6390
6391    #[crate::test(self)]
6392    fn test_observe_and_notify_from_view(cx: &mut MutableAppContext) {
6393        #[derive(Default)]
6394        struct View {
6395            events: Vec<usize>,
6396        }
6397
6398        impl Entity for View {
6399            type Event = usize;
6400        }
6401
6402        impl super::View for View {
6403            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6404                Empty::new().boxed()
6405            }
6406
6407            fn ui_name() -> &'static str {
6408                "View"
6409            }
6410        }
6411
6412        #[derive(Default)]
6413        struct Model {
6414            count: usize,
6415        }
6416
6417        impl Entity for Model {
6418            type Event = ();
6419        }
6420
6421        let (_, view) = cx.add_window(Default::default(), |_| View::default());
6422        let model = cx.add_model(|_| Model::default());
6423
6424        view.update(cx, |_, c| {
6425            c.observe(&model, |me, observed, c| {
6426                me.events.push(observed.read(c).count)
6427            })
6428            .detach();
6429        });
6430
6431        model.update(cx, |model, c| {
6432            model.count = 11;
6433            c.notify();
6434        });
6435        assert_eq!(view.read(cx).events, vec![11]);
6436    }
6437
6438    #[crate::test(self)]
6439    fn test_view_notify_before_observe_in_same_update_cycle(cx: &mut MutableAppContext) {
6440        #[derive(Default)]
6441        struct TestView;
6442
6443        impl Entity for TestView {
6444            type Event = ();
6445        }
6446
6447        impl View for TestView {
6448            fn ui_name() -> &'static str {
6449                "TestView"
6450            }
6451
6452            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6453                Empty::new().boxed()
6454            }
6455        }
6456
6457        let events = Rc::new(RefCell::new(Vec::new()));
6458        cx.add_window(Default::default(), |cx| {
6459            drop(cx.observe(&cx.handle(), {
6460                let events = events.clone();
6461                move |_, _, _| events.borrow_mut().push("dropped before flush")
6462            }));
6463            cx.observe(&cx.handle(), {
6464                let events = events.clone();
6465                move |_, _, _| events.borrow_mut().push("before notify")
6466            })
6467            .detach();
6468            cx.notify();
6469            cx.observe(&cx.handle(), {
6470                let events = events.clone();
6471                move |_, _, _| events.borrow_mut().push("after notify")
6472            })
6473            .detach();
6474            TestView
6475        });
6476        assert_eq!(*events.borrow(), ["before notify"]);
6477    }
6478
6479    #[crate::test(self)]
6480    fn test_dropping_observers(cx: &mut MutableAppContext) {
6481        struct View;
6482
6483        impl Entity for View {
6484            type Event = ();
6485        }
6486
6487        impl super::View for View {
6488            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6489                Empty::new().boxed()
6490            }
6491
6492            fn ui_name() -> &'static str {
6493                "View"
6494            }
6495        }
6496
6497        struct Model;
6498
6499        impl Entity for Model {
6500            type Event = ();
6501        }
6502
6503        let (window_id, _) = cx.add_window(Default::default(), |_| View);
6504        let observing_view = cx.add_view(window_id, |_| View);
6505        let observing_model = cx.add_model(|_| Model);
6506        let observed_model = cx.add_model(|_| Model);
6507
6508        observing_view.update(cx, |_, cx| {
6509            cx.observe(&observed_model, |_, _, _| {}).detach();
6510        });
6511        observing_model.update(cx, |_, cx| {
6512            cx.observe(&observed_model, |_, _, _| {}).detach();
6513        });
6514
6515        cx.update(|_| {
6516            drop(observing_view);
6517            drop(observing_model);
6518        });
6519
6520        observed_model.update(cx, |_, cx| cx.notify());
6521    }
6522
6523    #[crate::test(self)]
6524    fn test_dropping_subscriptions_during_callback(cx: &mut MutableAppContext) {
6525        struct Model;
6526
6527        impl Entity for Model {
6528            type Event = u64;
6529        }
6530
6531        // Events
6532        let observing_model = cx.add_model(|_| Model);
6533        let observed_model = cx.add_model(|_| Model);
6534
6535        let events = Rc::new(RefCell::new(Vec::new()));
6536
6537        observing_model.update(cx, |_, cx| {
6538            let events = events.clone();
6539            let subscription = Rc::new(RefCell::new(None));
6540            *subscription.borrow_mut() = Some(cx.subscribe(&observed_model, {
6541                let subscription = subscription.clone();
6542                move |_, _, e, _| {
6543                    subscription.borrow_mut().take();
6544                    events.borrow_mut().push(e.clone());
6545                }
6546            }));
6547        });
6548
6549        observed_model.update(cx, |_, cx| {
6550            cx.emit(1);
6551            cx.emit(2);
6552        });
6553
6554        assert_eq!(*events.borrow(), [1]);
6555
6556        // Global Events
6557        #[derive(Clone, Debug, Eq, PartialEq)]
6558        struct GlobalEvent(u64);
6559
6560        let events = Rc::new(RefCell::new(Vec::new()));
6561
6562        {
6563            let events = events.clone();
6564            let subscription = Rc::new(RefCell::new(None));
6565            *subscription.borrow_mut() = Some(cx.subscribe_global({
6566                let subscription = subscription.clone();
6567                move |e: &GlobalEvent, _| {
6568                    subscription.borrow_mut().take();
6569                    events.borrow_mut().push(e.clone());
6570                }
6571            }));
6572        }
6573
6574        cx.update(|cx| {
6575            cx.emit_global(GlobalEvent(1));
6576            cx.emit_global(GlobalEvent(2));
6577        });
6578
6579        assert_eq!(*events.borrow(), [GlobalEvent(1)]);
6580
6581        // Model Observation
6582        let observing_model = cx.add_model(|_| Model);
6583        let observed_model = cx.add_model(|_| Model);
6584
6585        let observation_count = Rc::new(RefCell::new(0));
6586
6587        observing_model.update(cx, |_, cx| {
6588            let observation_count = observation_count.clone();
6589            let subscription = Rc::new(RefCell::new(None));
6590            *subscription.borrow_mut() = Some(cx.observe(&observed_model, {
6591                let subscription = subscription.clone();
6592                move |_, _, _| {
6593                    subscription.borrow_mut().take();
6594                    *observation_count.borrow_mut() += 1;
6595                }
6596            }));
6597        });
6598
6599        observed_model.update(cx, |_, cx| {
6600            cx.notify();
6601        });
6602
6603        observed_model.update(cx, |_, cx| {
6604            cx.notify();
6605        });
6606
6607        assert_eq!(*observation_count.borrow(), 1);
6608
6609        // View Observation
6610        struct View;
6611
6612        impl Entity for View {
6613            type Event = ();
6614        }
6615
6616        impl super::View for View {
6617            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6618                Empty::new().boxed()
6619            }
6620
6621            fn ui_name() -> &'static str {
6622                "View"
6623            }
6624        }
6625
6626        let (window_id, _) = cx.add_window(Default::default(), |_| View);
6627        let observing_view = cx.add_view(window_id, |_| View);
6628        let observed_view = cx.add_view(window_id, |_| View);
6629
6630        let observation_count = Rc::new(RefCell::new(0));
6631        observing_view.update(cx, |_, cx| {
6632            let observation_count = observation_count.clone();
6633            let subscription = Rc::new(RefCell::new(None));
6634            *subscription.borrow_mut() = Some(cx.observe(&observed_view, {
6635                let subscription = subscription.clone();
6636                move |_, _, _| {
6637                    subscription.borrow_mut().take();
6638                    *observation_count.borrow_mut() += 1;
6639                }
6640            }));
6641        });
6642
6643        observed_view.update(cx, |_, cx| {
6644            cx.notify();
6645        });
6646
6647        observed_view.update(cx, |_, cx| {
6648            cx.notify();
6649        });
6650
6651        assert_eq!(*observation_count.borrow(), 1);
6652
6653        // Global Observation
6654        let observation_count = Rc::new(RefCell::new(0));
6655        let subscription = Rc::new(RefCell::new(None));
6656        *subscription.borrow_mut() = Some(cx.observe_global::<(), _>({
6657            let observation_count = observation_count.clone();
6658            let subscription = subscription.clone();
6659            move |_| {
6660                subscription.borrow_mut().take();
6661                *observation_count.borrow_mut() += 1;
6662            }
6663        }));
6664
6665        cx.default_global::<()>();
6666        cx.set_global(());
6667        assert_eq!(*observation_count.borrow(), 1);
6668    }
6669
6670    #[crate::test(self)]
6671    fn test_focus(cx: &mut MutableAppContext) {
6672        struct View {
6673            name: String,
6674            events: Arc<Mutex<Vec<String>>>,
6675        }
6676
6677        impl Entity for View {
6678            type Event = ();
6679        }
6680
6681        impl super::View for View {
6682            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6683                Empty::new().boxed()
6684            }
6685
6686            fn ui_name() -> &'static str {
6687                "View"
6688            }
6689
6690            fn on_focus(&mut self, _: &mut ViewContext<Self>) {
6691                self.events.lock().push(format!("{} focused", &self.name));
6692            }
6693
6694            fn on_blur(&mut self, _: &mut ViewContext<Self>) {
6695                self.events.lock().push(format!("{} blurred", &self.name));
6696            }
6697        }
6698
6699        let view_events: Arc<Mutex<Vec<String>>> = Default::default();
6700        let (window_id, view_1) = cx.add_window(Default::default(), |_| View {
6701            events: view_events.clone(),
6702            name: "view 1".to_string(),
6703        });
6704        let view_2 = cx.add_view(window_id, |_| View {
6705            events: view_events.clone(),
6706            name: "view 2".to_string(),
6707        });
6708
6709        let observed_events: Arc<Mutex<Vec<String>>> = Default::default();
6710        view_1.update(cx, |_, cx| {
6711            cx.observe_focus(&view_2, {
6712                let observed_events = observed_events.clone();
6713                move |this, view, focused, cx| {
6714                    let label = if focused { "focus" } else { "blur" };
6715                    observed_events.lock().push(format!(
6716                        "{} observed {}'s {}",
6717                        this.name,
6718                        view.read(cx).name,
6719                        label
6720                    ))
6721                }
6722            })
6723            .detach();
6724        });
6725        view_2.update(cx, |_, cx| {
6726            cx.observe_focus(&view_1, {
6727                let observed_events = observed_events.clone();
6728                move |this, view, focused, cx| {
6729                    let label = if focused { "focus" } else { "blur" };
6730                    observed_events.lock().push(format!(
6731                        "{} observed {}'s {}",
6732                        this.name,
6733                        view.read(cx).name,
6734                        label
6735                    ))
6736                }
6737            })
6738            .detach();
6739        });
6740        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
6741        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
6742
6743        view_1.update(cx, |_, cx| {
6744            // Ensure only the latest focus is honored.
6745            cx.focus(&view_2);
6746            cx.focus(&view_1);
6747            cx.focus(&view_2);
6748        });
6749        assert_eq!(
6750            mem::take(&mut *view_events.lock()),
6751            ["view 1 blurred", "view 2 focused"],
6752        );
6753        assert_eq!(
6754            mem::take(&mut *observed_events.lock()),
6755            [
6756                "view 2 observed view 1's blur",
6757                "view 1 observed view 2's focus"
6758            ]
6759        );
6760
6761        view_1.update(cx, |_, cx| cx.focus(&view_1));
6762        assert_eq!(
6763            mem::take(&mut *view_events.lock()),
6764            ["view 2 blurred", "view 1 focused"],
6765        );
6766        assert_eq!(
6767            mem::take(&mut *observed_events.lock()),
6768            [
6769                "view 1 observed view 2's blur",
6770                "view 2 observed view 1's focus"
6771            ]
6772        );
6773
6774        view_1.update(cx, |_, cx| cx.focus(&view_2));
6775        assert_eq!(
6776            mem::take(&mut *view_events.lock()),
6777            ["view 1 blurred", "view 2 focused"],
6778        );
6779        assert_eq!(
6780            mem::take(&mut *observed_events.lock()),
6781            [
6782                "view 2 observed view 1's blur",
6783                "view 1 observed view 2's focus"
6784            ]
6785        );
6786
6787        view_1.update(cx, |_, _| drop(view_2));
6788        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
6789        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
6790    }
6791
6792    #[crate::test(self)]
6793    fn test_deserialize_actions(cx: &mut MutableAppContext) {
6794        #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
6795        pub struct ComplexAction {
6796            arg: String,
6797            count: usize,
6798        }
6799
6800        actions!(test::something, [SimpleAction]);
6801        impl_actions!(test::something, [ComplexAction]);
6802
6803        cx.add_global_action(move |_: &SimpleAction, _: &mut MutableAppContext| {});
6804        cx.add_global_action(move |_: &ComplexAction, _: &mut MutableAppContext| {});
6805
6806        let action1 = cx
6807            .deserialize_action(
6808                "test::something::ComplexAction",
6809                Some(r#"{"arg": "a", "count": 5}"#),
6810            )
6811            .unwrap();
6812        let action2 = cx
6813            .deserialize_action("test::something::SimpleAction", None)
6814            .unwrap();
6815        assert_eq!(
6816            action1.as_any().downcast_ref::<ComplexAction>().unwrap(),
6817            &ComplexAction {
6818                arg: "a".to_string(),
6819                count: 5,
6820            }
6821        );
6822        assert_eq!(
6823            action2.as_any().downcast_ref::<SimpleAction>().unwrap(),
6824            &SimpleAction
6825        );
6826    }
6827
6828    #[crate::test(self)]
6829    fn test_dispatch_action(cx: &mut MutableAppContext) {
6830        struct ViewA {
6831            id: usize,
6832        }
6833
6834        impl Entity for ViewA {
6835            type Event = ();
6836        }
6837
6838        impl View for ViewA {
6839            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6840                Empty::new().boxed()
6841            }
6842
6843            fn ui_name() -> &'static str {
6844                "View"
6845            }
6846        }
6847
6848        struct ViewB {
6849            id: usize,
6850        }
6851
6852        impl Entity for ViewB {
6853            type Event = ();
6854        }
6855
6856        impl View for ViewB {
6857            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6858                Empty::new().boxed()
6859            }
6860
6861            fn ui_name() -> &'static str {
6862                "View"
6863            }
6864        }
6865
6866        #[derive(Clone, Default, Deserialize, PartialEq)]
6867        pub struct Action(pub String);
6868
6869        impl_actions!(test, [Action]);
6870
6871        let actions = Rc::new(RefCell::new(Vec::new()));
6872
6873        cx.add_global_action({
6874            let actions = actions.clone();
6875            move |_: &Action, _: &mut MutableAppContext| {
6876                actions.borrow_mut().push("global".to_string());
6877            }
6878        });
6879
6880        cx.add_action({
6881            let actions = actions.clone();
6882            move |view: &mut ViewA, action: &Action, cx| {
6883                assert_eq!(action.0, "bar");
6884                cx.propagate_action();
6885                actions.borrow_mut().push(format!("{} a", view.id));
6886            }
6887        });
6888
6889        cx.add_action({
6890            let actions = actions.clone();
6891            move |view: &mut ViewA, _: &Action, cx| {
6892                if view.id != 1 {
6893                    cx.add_view(|cx| {
6894                        cx.propagate_action(); // Still works on a nested ViewContext
6895                        ViewB { id: 5 }
6896                    });
6897                }
6898                actions.borrow_mut().push(format!("{} b", view.id));
6899            }
6900        });
6901
6902        cx.add_action({
6903            let actions = actions.clone();
6904            move |view: &mut ViewB, _: &Action, cx| {
6905                cx.propagate_action();
6906                actions.borrow_mut().push(format!("{} c", view.id));
6907            }
6908        });
6909
6910        cx.add_action({
6911            let actions = actions.clone();
6912            move |view: &mut ViewB, _: &Action, cx| {
6913                cx.propagate_action();
6914                actions.borrow_mut().push(format!("{} d", view.id));
6915            }
6916        });
6917
6918        cx.capture_action({
6919            let actions = actions.clone();
6920            move |view: &mut ViewA, _: &Action, cx| {
6921                cx.propagate_action();
6922                actions.borrow_mut().push(format!("{} capture", view.id));
6923            }
6924        });
6925
6926        let (window_id, view_1) = cx.add_window(Default::default(), |_| ViewA { id: 1 });
6927        let view_2 = cx.add_view(window_id, |_| ViewB { id: 2 });
6928        let view_3 = cx.add_view(window_id, |_| ViewA { id: 3 });
6929        let view_4 = cx.add_view(window_id, |_| ViewB { id: 4 });
6930
6931        let observed_actions = Rc::new(RefCell::new(Vec::new()));
6932        cx.observe_actions({
6933            let observed_actions = observed_actions.clone();
6934            move |action_id, _| observed_actions.borrow_mut().push(action_id)
6935        })
6936        .detach();
6937
6938        cx.dispatch_action(
6939            window_id,
6940            vec![view_1.id(), view_2.id(), view_3.id(), view_4.id()],
6941            &Action("bar".to_string()),
6942        );
6943
6944        assert_eq!(
6945            *actions.borrow(),
6946            vec![
6947                "1 capture",
6948                "3 capture",
6949                "4 d",
6950                "4 c",
6951                "3 b",
6952                "3 a",
6953                "2 d",
6954                "2 c",
6955                "1 b"
6956            ]
6957        );
6958        assert_eq!(*observed_actions.borrow(), [Action::default().id()]);
6959
6960        // Remove view_1, which doesn't propagate the action
6961        actions.borrow_mut().clear();
6962        cx.dispatch_action(
6963            window_id,
6964            vec![view_2.id(), view_3.id(), view_4.id()],
6965            &Action("bar".to_string()),
6966        );
6967
6968        assert_eq!(
6969            *actions.borrow(),
6970            vec![
6971                "3 capture",
6972                "4 d",
6973                "4 c",
6974                "3 b",
6975                "3 a",
6976                "2 d",
6977                "2 c",
6978                "global"
6979            ]
6980        );
6981        assert_eq!(
6982            *observed_actions.borrow(),
6983            [Action::default().id(), Action::default().id()]
6984        );
6985    }
6986
6987    #[crate::test(self)]
6988    fn test_dispatch_keystroke(cx: &mut MutableAppContext) {
6989        #[derive(Clone, Deserialize, PartialEq)]
6990        pub struct Action(String);
6991
6992        impl_actions!(test, [Action]);
6993
6994        struct View {
6995            id: usize,
6996            keymap_context: keymap::Context,
6997        }
6998
6999        impl Entity for View {
7000            type Event = ();
7001        }
7002
7003        impl super::View for View {
7004            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7005                Empty::new().boxed()
7006            }
7007
7008            fn ui_name() -> &'static str {
7009                "View"
7010            }
7011
7012            fn keymap_context(&self, _: &AppContext) -> keymap::Context {
7013                self.keymap_context.clone()
7014            }
7015        }
7016
7017        impl View {
7018            fn new(id: usize) -> Self {
7019                View {
7020                    id,
7021                    keymap_context: keymap::Context::default(),
7022                }
7023            }
7024        }
7025
7026        let mut view_1 = View::new(1);
7027        let mut view_2 = View::new(2);
7028        let mut view_3 = View::new(3);
7029        view_1.keymap_context.set.insert("a".into());
7030        view_2.keymap_context.set.insert("a".into());
7031        view_2.keymap_context.set.insert("b".into());
7032        view_3.keymap_context.set.insert("a".into());
7033        view_3.keymap_context.set.insert("b".into());
7034        view_3.keymap_context.set.insert("c".into());
7035
7036        let (window_id, view_1) = cx.add_window(Default::default(), |_| view_1);
7037        let view_2 = cx.add_view(window_id, |_| view_2);
7038        let view_3 = cx.add_view(window_id, |_| view_3);
7039
7040        // This keymap's only binding dispatches an action on view 2 because that view will have
7041        // "a" and "b" in its context, but not "c".
7042        cx.add_bindings(vec![keymap::Binding::new(
7043            "a",
7044            Action("a".to_string()),
7045            Some("a && b && !c"),
7046        )]);
7047
7048        cx.add_bindings(vec![keymap::Binding::new(
7049            "b",
7050            Action("b".to_string()),
7051            None,
7052        )]);
7053
7054        let actions = Rc::new(RefCell::new(Vec::new()));
7055        cx.add_action({
7056            let actions = actions.clone();
7057            move |view: &mut View, action: &Action, cx| {
7058                if action.0 == "a" {
7059                    actions.borrow_mut().push(format!("{} a", view.id));
7060                } else {
7061                    actions
7062                        .borrow_mut()
7063                        .push(format!("{} {}", view.id, action.0));
7064                    cx.propagate_action();
7065                }
7066            }
7067        });
7068
7069        cx.add_global_action({
7070            let actions = actions.clone();
7071            move |action: &Action, _| {
7072                actions.borrow_mut().push(format!("global {}", action.0));
7073            }
7074        });
7075
7076        cx.dispatch_keystroke(
7077            window_id,
7078            vec![view_1.id(), view_2.id(), view_3.id()],
7079            &Keystroke::parse("a").unwrap(),
7080        );
7081
7082        assert_eq!(&*actions.borrow(), &["2 a"]);
7083
7084        actions.borrow_mut().clear();
7085        cx.dispatch_keystroke(
7086            window_id,
7087            vec![view_1.id(), view_2.id(), view_3.id()],
7088            &Keystroke::parse("b").unwrap(),
7089        );
7090
7091        assert_eq!(&*actions.borrow(), &["3 b", "2 b", "1 b", "global b"]);
7092    }
7093
7094    #[crate::test(self)]
7095    async fn test_model_condition(cx: &mut TestAppContext) {
7096        struct Counter(usize);
7097
7098        impl super::Entity for Counter {
7099            type Event = ();
7100        }
7101
7102        impl Counter {
7103            fn inc(&mut self, cx: &mut ModelContext<Self>) {
7104                self.0 += 1;
7105                cx.notify();
7106            }
7107        }
7108
7109        let model = cx.add_model(|_| Counter(0));
7110
7111        let condition1 = model.condition(&cx, |model, _| model.0 == 2);
7112        let condition2 = model.condition(&cx, |model, _| model.0 == 3);
7113        smol::pin!(condition1, condition2);
7114
7115        model.update(cx, |model, cx| model.inc(cx));
7116        assert_eq!(poll_once(&mut condition1).await, None);
7117        assert_eq!(poll_once(&mut condition2).await, None);
7118
7119        model.update(cx, |model, cx| model.inc(cx));
7120        assert_eq!(poll_once(&mut condition1).await, Some(()));
7121        assert_eq!(poll_once(&mut condition2).await, None);
7122
7123        model.update(cx, |model, cx| model.inc(cx));
7124        assert_eq!(poll_once(&mut condition2).await, Some(()));
7125
7126        model.update(cx, |_, cx| cx.notify());
7127    }
7128
7129    #[crate::test(self)]
7130    #[should_panic]
7131    async fn test_model_condition_timeout(cx: &mut TestAppContext) {
7132        struct Model;
7133
7134        impl super::Entity for Model {
7135            type Event = ();
7136        }
7137
7138        let model = cx.add_model(|_| Model);
7139        model.condition(&cx, |_, _| false).await;
7140    }
7141
7142    #[crate::test(self)]
7143    #[should_panic(expected = "model dropped with pending condition")]
7144    async fn test_model_condition_panic_on_drop(cx: &mut TestAppContext) {
7145        struct Model;
7146
7147        impl super::Entity for Model {
7148            type Event = ();
7149        }
7150
7151        let model = cx.add_model(|_| Model);
7152        let condition = model.condition(&cx, |_, _| false);
7153        cx.update(|_| drop(model));
7154        condition.await;
7155    }
7156
7157    #[crate::test(self)]
7158    async fn test_view_condition(cx: &mut TestAppContext) {
7159        struct Counter(usize);
7160
7161        impl super::Entity for Counter {
7162            type Event = ();
7163        }
7164
7165        impl super::View for Counter {
7166            fn ui_name() -> &'static str {
7167                "test view"
7168            }
7169
7170            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7171                Empty::new().boxed()
7172            }
7173        }
7174
7175        impl Counter {
7176            fn inc(&mut self, cx: &mut ViewContext<Self>) {
7177                self.0 += 1;
7178                cx.notify();
7179            }
7180        }
7181
7182        let (_, view) = cx.add_window(|_| Counter(0));
7183
7184        let condition1 = view.condition(&cx, |view, _| view.0 == 2);
7185        let condition2 = view.condition(&cx, |view, _| view.0 == 3);
7186        smol::pin!(condition1, condition2);
7187
7188        view.update(cx, |view, cx| view.inc(cx));
7189        assert_eq!(poll_once(&mut condition1).await, None);
7190        assert_eq!(poll_once(&mut condition2).await, None);
7191
7192        view.update(cx, |view, cx| view.inc(cx));
7193        assert_eq!(poll_once(&mut condition1).await, Some(()));
7194        assert_eq!(poll_once(&mut condition2).await, None);
7195
7196        view.update(cx, |view, cx| view.inc(cx));
7197        assert_eq!(poll_once(&mut condition2).await, Some(()));
7198        view.update(cx, |_, cx| cx.notify());
7199    }
7200
7201    #[crate::test(self)]
7202    #[should_panic]
7203    async fn test_view_condition_timeout(cx: &mut TestAppContext) {
7204        struct View;
7205
7206        impl super::Entity for View {
7207            type Event = ();
7208        }
7209
7210        impl super::View for View {
7211            fn ui_name() -> &'static str {
7212                "test view"
7213            }
7214
7215            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7216                Empty::new().boxed()
7217            }
7218        }
7219
7220        let (_, view) = cx.add_window(|_| View);
7221        view.condition(&cx, |_, _| false).await;
7222    }
7223
7224    #[crate::test(self)]
7225    #[should_panic(expected = "view dropped with pending condition")]
7226    async fn test_view_condition_panic_on_drop(cx: &mut TestAppContext) {
7227        struct View;
7228
7229        impl super::Entity for View {
7230            type Event = ();
7231        }
7232
7233        impl super::View for View {
7234            fn ui_name() -> &'static str {
7235                "test view"
7236            }
7237
7238            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7239                Empty::new().boxed()
7240            }
7241        }
7242
7243        let window_id = cx.add_window(|_| View).0;
7244        let view = cx.add_view(window_id, |_| View);
7245
7246        let condition = view.condition(&cx, |_, _| false);
7247        cx.update(|_| drop(view));
7248        condition.await;
7249    }
7250
7251    #[crate::test(self)]
7252    fn test_refresh_windows(cx: &mut MutableAppContext) {
7253        struct View(usize);
7254
7255        impl super::Entity for View {
7256            type Event = ();
7257        }
7258
7259        impl super::View for View {
7260            fn ui_name() -> &'static str {
7261                "test view"
7262            }
7263
7264            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7265                Empty::new().named(format!("render count: {}", post_inc(&mut self.0)))
7266            }
7267        }
7268
7269        let (window_id, root_view) = cx.add_window(Default::default(), |_| View(0));
7270        let presenter = cx.presenters_and_platform_windows[&window_id].0.clone();
7271
7272        assert_eq!(
7273            presenter.borrow().rendered_views[&root_view.id()].name(),
7274            Some("render count: 0")
7275        );
7276
7277        let view = cx.add_view(window_id, |cx| {
7278            cx.refresh_windows();
7279            View(0)
7280        });
7281
7282        assert_eq!(
7283            presenter.borrow().rendered_views[&root_view.id()].name(),
7284            Some("render count: 1")
7285        );
7286        assert_eq!(
7287            presenter.borrow().rendered_views[&view.id()].name(),
7288            Some("render count: 0")
7289        );
7290
7291        cx.update(|cx| cx.refresh_windows());
7292        assert_eq!(
7293            presenter.borrow().rendered_views[&root_view.id()].name(),
7294            Some("render count: 2")
7295        );
7296        assert_eq!(
7297            presenter.borrow().rendered_views[&view.id()].name(),
7298            Some("render count: 1")
7299        );
7300
7301        cx.update(|cx| {
7302            cx.refresh_windows();
7303            drop(view);
7304        });
7305        assert_eq!(
7306            presenter.borrow().rendered_views[&root_view.id()].name(),
7307            Some("render count: 3")
7308        );
7309        assert_eq!(presenter.borrow().rendered_views.len(), 1);
7310    }
7311
7312    #[crate::test(self)]
7313    async fn test_window_activation(cx: &mut TestAppContext) {
7314        struct View(&'static str);
7315
7316        impl super::Entity for View {
7317            type Event = ();
7318        }
7319
7320        impl super::View for View {
7321            fn ui_name() -> &'static str {
7322                "test view"
7323            }
7324
7325            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7326                Empty::new().boxed()
7327            }
7328        }
7329
7330        let events = Rc::new(RefCell::new(Vec::new()));
7331        let (window_1, _) = cx.add_window(|cx: &mut ViewContext<View>| {
7332            cx.observe_window_activation({
7333                let events = events.clone();
7334                move |this, active, _| events.borrow_mut().push((this.0, active))
7335            })
7336            .detach();
7337            View("window 1")
7338        });
7339        assert_eq!(mem::take(&mut *events.borrow_mut()), [("window 1", true)]);
7340
7341        let (window_2, _) = cx.add_window(|cx: &mut ViewContext<View>| {
7342            cx.observe_window_activation({
7343                let events = events.clone();
7344                move |this, active, _| events.borrow_mut().push((this.0, active))
7345            })
7346            .detach();
7347            View("window 2")
7348        });
7349        assert_eq!(
7350            mem::take(&mut *events.borrow_mut()),
7351            [("window 1", false), ("window 2", true)]
7352        );
7353
7354        let (window_3, _) = cx.add_window(|cx: &mut ViewContext<View>| {
7355            cx.observe_window_activation({
7356                let events = events.clone();
7357                move |this, active, _| events.borrow_mut().push((this.0, active))
7358            })
7359            .detach();
7360            View("window 3")
7361        });
7362        assert_eq!(
7363            mem::take(&mut *events.borrow_mut()),
7364            [("window 2", false), ("window 3", true)]
7365        );
7366
7367        cx.simulate_window_activation(Some(window_2));
7368        assert_eq!(
7369            mem::take(&mut *events.borrow_mut()),
7370            [("window 3", false), ("window 2", true)]
7371        );
7372
7373        cx.simulate_window_activation(Some(window_1));
7374        assert_eq!(
7375            mem::take(&mut *events.borrow_mut()),
7376            [("window 2", false), ("window 1", true)]
7377        );
7378
7379        cx.simulate_window_activation(Some(window_3));
7380        assert_eq!(
7381            mem::take(&mut *events.borrow_mut()),
7382            [("window 1", false), ("window 3", true)]
7383        );
7384
7385        cx.simulate_window_activation(Some(window_3));
7386        assert_eq!(mem::take(&mut *events.borrow_mut()), []);
7387    }
7388}