app.rs

   1pub mod action;
   2mod callback_collection;
   3
   4use crate::{
   5    elements::ElementBox,
   6    executor::{self, Task},
   7    geometry::rect::RectF,
   8    keymap::{self, Binding, Keystroke},
   9    platform::{self, KeyDownEvent, Platform, PromptLevel, WindowOptions},
  10    presenter::Presenter,
  11    util::post_inc,
  12    AssetCache, AssetSource, ClipboardItem, FontCache, InputHandler, MouseButton, MouseRegionId,
  13    PathPromptOptions, TextLayoutCache,
  14};
  15pub use action::*;
  16use anyhow::{anyhow, Context, Result};
  17use callback_collection::CallbackCollection;
  18use collections::{btree_map, hash_map::Entry, BTreeMap, HashMap, HashSet, VecDeque};
  19use keymap::MatchResult;
  20use lazy_static::lazy_static;
  21use parking_lot::Mutex;
  22use platform::Event;
  23use postage::oneshot;
  24use smallvec::SmallVec;
  25use smol::prelude::*;
  26use std::{
  27    any::{type_name, Any, TypeId},
  28    cell::RefCell,
  29    fmt::{self, Debug},
  30    hash::{Hash, Hasher},
  31    marker::PhantomData,
  32    mem,
  33    ops::{Deref, DerefMut, Range},
  34    path::{Path, PathBuf},
  35    pin::Pin,
  36    rc::{self, Rc},
  37    sync::{Arc, Weak},
  38    time::Duration,
  39};
  40
  41use self::callback_collection::Mapping;
  42
  43pub trait Entity: 'static {
  44    type Event;
  45
  46    fn release(&mut self, _: &mut MutableAppContext) {}
  47    fn app_will_quit(
  48        &mut self,
  49        _: &mut MutableAppContext,
  50    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
  51        None
  52    }
  53}
  54
  55pub trait View: Entity + Sized {
  56    fn ui_name() -> &'static str;
  57    fn render(&mut self, cx: &mut RenderContext<'_, Self>) -> ElementBox;
  58    fn on_focus_in(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  59    fn on_focus_out(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  60    fn keymap_context(&self, _: &AppContext) -> keymap::Context {
  61        Self::default_keymap_context()
  62    }
  63    fn default_keymap_context() -> keymap::Context {
  64        let mut cx = keymap::Context::default();
  65        cx.set.insert(Self::ui_name().into());
  66        cx
  67    }
  68    fn debug_json(&self, _: &AppContext) -> serde_json::Value {
  69        serde_json::Value::Null
  70    }
  71
  72    fn text_for_range(&self, _: Range<usize>, _: &AppContext) -> Option<String> {
  73        None
  74    }
  75    fn selected_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
  76        None
  77    }
  78    fn marked_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
  79        None
  80    }
  81    fn unmark_text(&mut self, _: &mut ViewContext<Self>) {}
  82    fn replace_text_in_range(
  83        &mut self,
  84        _: Option<Range<usize>>,
  85        _: &str,
  86        _: &mut ViewContext<Self>,
  87    ) {
  88    }
  89    fn replace_and_mark_text_in_range(
  90        &mut self,
  91        _: Option<Range<usize>>,
  92        _: &str,
  93        _: Option<Range<usize>>,
  94        _: &mut ViewContext<Self>,
  95    ) {
  96    }
  97}
  98
  99pub trait ReadModel {
 100    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T;
 101}
 102
 103pub trait ReadModelWith {
 104    fn read_model_with<E: Entity, T>(
 105        &self,
 106        handle: &ModelHandle<E>,
 107        read: &mut dyn FnMut(&E, &AppContext) -> T,
 108    ) -> T;
 109}
 110
 111pub trait UpdateModel {
 112    fn update_model<T: Entity, O>(
 113        &mut self,
 114        handle: &ModelHandle<T>,
 115        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
 116    ) -> O;
 117}
 118
 119pub trait UpgradeModelHandle {
 120    fn upgrade_model_handle<T: Entity>(
 121        &self,
 122        handle: &WeakModelHandle<T>,
 123    ) -> Option<ModelHandle<T>>;
 124
 125    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool;
 126
 127    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle>;
 128}
 129
 130pub trait UpgradeViewHandle {
 131    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>>;
 132
 133    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle>;
 134}
 135
 136pub trait ReadView {
 137    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T;
 138}
 139
 140pub trait ReadViewWith {
 141    fn read_view_with<V, T>(
 142        &self,
 143        handle: &ViewHandle<V>,
 144        read: &mut dyn FnMut(&V, &AppContext) -> T,
 145    ) -> T
 146    where
 147        V: View;
 148}
 149
 150pub trait UpdateView {
 151    fn update_view<T, S>(
 152        &mut self,
 153        handle: &ViewHandle<T>,
 154        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
 155    ) -> S
 156    where
 157        T: View;
 158}
 159
 160pub struct Menu<'a> {
 161    pub name: &'a str,
 162    pub items: Vec<MenuItem<'a>>,
 163}
 164
 165pub enum MenuItem<'a> {
 166    Separator,
 167    Submenu(Menu<'a>),
 168    Action {
 169        name: &'a str,
 170        action: Box<dyn Action>,
 171    },
 172}
 173
 174#[derive(Clone)]
 175pub struct App(Rc<RefCell<MutableAppContext>>);
 176
 177#[derive(Clone)]
 178pub struct AsyncAppContext(Rc<RefCell<MutableAppContext>>);
 179
 180#[cfg(any(test, feature = "test-support"))]
 181pub struct TestAppContext {
 182    cx: Rc<RefCell<MutableAppContext>>,
 183    foreground_platform: Rc<platform::test::ForegroundPlatform>,
 184    condition_duration: Option<Duration>,
 185}
 186
 187pub struct WindowInputHandler {
 188    app: Rc<RefCell<MutableAppContext>>,
 189    window_id: usize,
 190}
 191
 192impl App {
 193    pub fn new(asset_source: impl AssetSource) -> Result<Self> {
 194        let platform = platform::current::platform();
 195        let foreground_platform = platform::current::foreground_platform();
 196        let foreground = Rc::new(executor::Foreground::platform(platform.dispatcher())?);
 197        let app = Self(Rc::new(RefCell::new(MutableAppContext::new(
 198            foreground,
 199            Arc::new(executor::Background::new()),
 200            platform.clone(),
 201            foreground_platform.clone(),
 202            Arc::new(FontCache::new(platform.fonts())),
 203            Default::default(),
 204            asset_source,
 205        ))));
 206
 207        foreground_platform.on_quit(Box::new({
 208            let cx = app.0.clone();
 209            move || {
 210                cx.borrow_mut().quit();
 211            }
 212        }));
 213        foreground_platform.on_will_open_menu(Box::new({
 214            let cx = app.0.clone();
 215            move || {
 216                let mut cx = cx.borrow_mut();
 217                cx.keystroke_matcher.clear_pending();
 218            }
 219        }));
 220        foreground_platform.on_validate_menu_command(Box::new({
 221            let cx = app.0.clone();
 222            move |action| {
 223                let cx = cx.borrow_mut();
 224                !cx.keystroke_matcher.has_pending_keystrokes() && cx.is_action_available(action)
 225            }
 226        }));
 227        foreground_platform.on_menu_command(Box::new({
 228            let cx = app.0.clone();
 229            move |action| {
 230                let mut cx = cx.borrow_mut();
 231                if let Some(key_window_id) = cx.cx.platform.key_window_id() {
 232                    if let Some(view_id) = cx.focused_view_id(key_window_id) {
 233                        cx.handle_dispatch_action_from_effect(key_window_id, Some(view_id), action);
 234                        return;
 235                    }
 236                }
 237                cx.dispatch_global_action_any(action);
 238            }
 239        }));
 240
 241        app.0.borrow_mut().weak_self = Some(Rc::downgrade(&app.0));
 242        Ok(app)
 243    }
 244
 245    pub fn background(&self) -> Arc<executor::Background> {
 246        self.0.borrow().background().clone()
 247    }
 248
 249    pub fn on_become_active<F>(self, mut callback: F) -> Self
 250    where
 251        F: 'static + FnMut(&mut MutableAppContext),
 252    {
 253        let cx = self.0.clone();
 254        self.0
 255            .borrow_mut()
 256            .foreground_platform
 257            .on_become_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 258        self
 259    }
 260
 261    pub fn on_resign_active<F>(self, mut callback: F) -> Self
 262    where
 263        F: 'static + FnMut(&mut MutableAppContext),
 264    {
 265        let cx = self.0.clone();
 266        self.0
 267            .borrow_mut()
 268            .foreground_platform
 269            .on_resign_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 270        self
 271    }
 272
 273    pub fn on_quit<F>(&mut self, mut callback: F) -> &mut Self
 274    where
 275        F: 'static + FnMut(&mut MutableAppContext),
 276    {
 277        let cx = self.0.clone();
 278        self.0
 279            .borrow_mut()
 280            .foreground_platform
 281            .on_quit(Box::new(move || callback(&mut *cx.borrow_mut())));
 282        self
 283    }
 284
 285    pub fn on_event<F>(&mut self, mut callback: F) -> &mut Self
 286    where
 287        F: 'static + FnMut(Event, &mut MutableAppContext) -> bool,
 288    {
 289        let cx = self.0.clone();
 290        self.0
 291            .borrow_mut()
 292            .foreground_platform
 293            .on_event(Box::new(move |event| {
 294                callback(event, &mut *cx.borrow_mut())
 295            }));
 296        self
 297    }
 298
 299    pub fn on_open_urls<F>(&mut self, mut callback: F) -> &mut Self
 300    where
 301        F: 'static + FnMut(Vec<String>, &mut MutableAppContext),
 302    {
 303        let cx = self.0.clone();
 304        self.0
 305            .borrow_mut()
 306            .foreground_platform
 307            .on_open_urls(Box::new(move |paths| {
 308                callback(paths, &mut *cx.borrow_mut())
 309            }));
 310        self
 311    }
 312
 313    pub fn run<F>(self, on_finish_launching: F)
 314    where
 315        F: 'static + FnOnce(&mut MutableAppContext),
 316    {
 317        let platform = self.0.borrow().foreground_platform.clone();
 318        platform.run(Box::new(move || {
 319            let mut cx = self.0.borrow_mut();
 320            let cx = &mut *cx;
 321            crate::views::init(cx);
 322            on_finish_launching(cx);
 323        }))
 324    }
 325
 326    pub fn platform(&self) -> Arc<dyn Platform> {
 327        self.0.borrow().platform()
 328    }
 329
 330    pub fn font_cache(&self) -> Arc<FontCache> {
 331        self.0.borrow().cx.font_cache.clone()
 332    }
 333
 334    fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 335        let mut state = self.0.borrow_mut();
 336        let result = state.update(callback);
 337        state.pending_notifications.clear();
 338        result
 339    }
 340}
 341
 342impl WindowInputHandler {
 343    fn read_focused_view<T, F>(&self, f: F) -> Option<T>
 344    where
 345        F: FnOnce(&dyn AnyView, &AppContext) -> T,
 346    {
 347        // Input-related application hooks are sometimes called by the OS during
 348        // a call to a window-manipulation API, like prompting the user for file
 349        // paths. In that case, the AppContext will already be borrowed, so any
 350        // InputHandler methods need to fail gracefully.
 351        //
 352        // See https://github.com/zed-industries/feedback/issues/444
 353        let app = self.app.try_borrow().ok()?;
 354
 355        let view_id = app.focused_view_id(self.window_id)?;
 356        let view = app.cx.views.get(&(self.window_id, view_id))?;
 357        let result = f(view.as_ref(), &app);
 358        Some(result)
 359    }
 360
 361    fn update_focused_view<T, F>(&mut self, f: F) -> Option<T>
 362    where
 363        F: FnOnce(usize, usize, &mut dyn AnyView, &mut MutableAppContext) -> T,
 364    {
 365        let mut app = self.app.try_borrow_mut().ok()?;
 366        app.update(|app| {
 367            let view_id = app.focused_view_id(self.window_id)?;
 368            let mut view = app.cx.views.remove(&(self.window_id, view_id))?;
 369            let result = f(self.window_id, view_id, view.as_mut(), &mut *app);
 370            app.cx.views.insert((self.window_id, view_id), view);
 371            Some(result)
 372        })
 373    }
 374}
 375
 376impl InputHandler for WindowInputHandler {
 377    fn text_for_range(&self, range: Range<usize>) -> Option<String> {
 378        self.read_focused_view(|view, cx| view.text_for_range(range.clone(), cx))
 379            .flatten()
 380    }
 381
 382    fn selected_text_range(&self) -> Option<Range<usize>> {
 383        self.read_focused_view(|view, cx| view.selected_text_range(cx))
 384            .flatten()
 385    }
 386
 387    fn replace_text_in_range(&mut self, range: Option<Range<usize>>, text: &str) {
 388        self.update_focused_view(|window_id, view_id, view, cx| {
 389            view.replace_text_in_range(range, text, cx, window_id, view_id);
 390        });
 391    }
 392
 393    fn marked_text_range(&self) -> Option<Range<usize>> {
 394        self.read_focused_view(|view, cx| view.marked_text_range(cx))
 395            .flatten()
 396    }
 397
 398    fn unmark_text(&mut self) {
 399        self.update_focused_view(|window_id, view_id, view, cx| {
 400            view.unmark_text(cx, window_id, view_id);
 401        });
 402    }
 403
 404    fn replace_and_mark_text_in_range(
 405        &mut self,
 406        range: Option<Range<usize>>,
 407        new_text: &str,
 408        new_selected_range: Option<Range<usize>>,
 409    ) {
 410        self.update_focused_view(|window_id, view_id, view, cx| {
 411            view.replace_and_mark_text_in_range(
 412                range,
 413                new_text,
 414                new_selected_range,
 415                cx,
 416                window_id,
 417                view_id,
 418            );
 419        });
 420    }
 421
 422    fn rect_for_range(&self, range_utf16: Range<usize>) -> Option<RectF> {
 423        let app = self.app.borrow();
 424        let (presenter, _) = app.presenters_and_platform_windows.get(&self.window_id)?;
 425        let presenter = presenter.borrow();
 426        presenter.rect_for_text_range(range_utf16, &app)
 427    }
 428}
 429
 430#[cfg(any(test, feature = "test-support"))]
 431impl TestAppContext {
 432    pub fn new(
 433        foreground_platform: Rc<platform::test::ForegroundPlatform>,
 434        platform: Arc<dyn Platform>,
 435        foreground: Rc<executor::Foreground>,
 436        background: Arc<executor::Background>,
 437        font_cache: Arc<FontCache>,
 438        leak_detector: Arc<Mutex<LeakDetector>>,
 439        first_entity_id: usize,
 440    ) -> Self {
 441        let mut cx = MutableAppContext::new(
 442            foreground,
 443            background,
 444            platform,
 445            foreground_platform.clone(),
 446            font_cache,
 447            RefCounts {
 448                #[cfg(any(test, feature = "test-support"))]
 449                leak_detector,
 450                ..Default::default()
 451            },
 452            (),
 453        );
 454        cx.next_entity_id = first_entity_id;
 455        let cx = TestAppContext {
 456            cx: Rc::new(RefCell::new(cx)),
 457            foreground_platform,
 458            condition_duration: None,
 459        };
 460        cx.cx.borrow_mut().weak_self = Some(Rc::downgrade(&cx.cx));
 461        cx
 462    }
 463
 464    pub fn dispatch_action<A: Action>(&self, window_id: usize, action: A) {
 465        let mut cx = self.cx.borrow_mut();
 466        if let Some(view_id) = cx.focused_view_id(window_id) {
 467            cx.handle_dispatch_action_from_effect(window_id, Some(view_id), &action);
 468        }
 469    }
 470
 471    pub fn dispatch_global_action<A: Action>(&self, action: A) {
 472        self.cx.borrow_mut().dispatch_global_action(action);
 473    }
 474
 475    pub fn dispatch_keystroke(&mut self, window_id: usize, keystroke: Keystroke, is_held: bool) {
 476        let handled = self.cx.borrow_mut().update(|cx| {
 477            let presenter = cx
 478                .presenters_and_platform_windows
 479                .get(&window_id)
 480                .unwrap()
 481                .0
 482                .clone();
 483
 484            if cx.dispatch_keystroke(window_id, &keystroke) {
 485                return true;
 486            }
 487
 488            if presenter.borrow_mut().dispatch_event(
 489                Event::KeyDown(KeyDownEvent {
 490                    keystroke: keystroke.clone(),
 491                    is_held,
 492                }),
 493                false,
 494                cx,
 495            ) {
 496                return true;
 497            }
 498
 499            false
 500        });
 501
 502        if !handled && !keystroke.cmd && !keystroke.ctrl {
 503            WindowInputHandler {
 504                app: self.cx.clone(),
 505                window_id,
 506            }
 507            .replace_text_in_range(None, &keystroke.key)
 508        }
 509    }
 510
 511    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 512    where
 513        T: Entity,
 514        F: FnOnce(&mut ModelContext<T>) -> T,
 515    {
 516        self.cx.borrow_mut().add_model(build_model)
 517    }
 518
 519    pub fn add_window<T, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<T>)
 520    where
 521        T: View,
 522        F: FnOnce(&mut ViewContext<T>) -> T,
 523    {
 524        let (window_id, view) = self
 525            .cx
 526            .borrow_mut()
 527            .add_window(Default::default(), build_root_view);
 528        self.simulate_window_activation(Some(window_id));
 529        (window_id, view)
 530    }
 531
 532    pub fn add_view<T, F>(
 533        &mut self,
 534        parent_handle: impl Into<AnyViewHandle>,
 535        build_view: F,
 536    ) -> ViewHandle<T>
 537    where
 538        T: View,
 539        F: FnOnce(&mut ViewContext<T>) -> T,
 540    {
 541        self.cx.borrow_mut().add_view(parent_handle, build_view)
 542    }
 543
 544    pub fn window_ids(&self) -> Vec<usize> {
 545        self.cx.borrow().window_ids().collect()
 546    }
 547
 548    pub fn root_view<T: View>(&self, window_id: usize) -> Option<ViewHandle<T>> {
 549        self.cx.borrow().root_view(window_id)
 550    }
 551
 552    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 553        callback(self.cx.borrow().as_ref())
 554    }
 555
 556    pub fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 557        let mut state = self.cx.borrow_mut();
 558        // Don't increment pending flushes in order for effects to be flushed before the callback
 559        // completes, which is helpful in tests.
 560        let result = callback(&mut *state);
 561        // Flush effects after the callback just in case there are any. This can happen in edge
 562        // cases such as the closure dropping handles.
 563        state.flush_effects();
 564        result
 565    }
 566
 567    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
 568    where
 569        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
 570        V: View,
 571    {
 572        handle.update(&mut *self.cx.borrow_mut(), |view, cx| {
 573            let mut render_cx = RenderContext {
 574                app: cx,
 575                window_id: handle.window_id(),
 576                view_id: handle.id(),
 577                view_type: PhantomData,
 578                titlebar_height: 0.,
 579                hovered_region_ids: Default::default(),
 580                clicked_region_ids: None,
 581                refreshing: false,
 582            };
 583            f(view, &mut render_cx)
 584        })
 585    }
 586
 587    pub fn to_async(&self) -> AsyncAppContext {
 588        AsyncAppContext(self.cx.clone())
 589    }
 590
 591    pub fn font_cache(&self) -> Arc<FontCache> {
 592        self.cx.borrow().cx.font_cache.clone()
 593    }
 594
 595    pub fn foreground_platform(&self) -> Rc<platform::test::ForegroundPlatform> {
 596        self.foreground_platform.clone()
 597    }
 598
 599    pub fn platform(&self) -> Arc<dyn platform::Platform> {
 600        self.cx.borrow().cx.platform.clone()
 601    }
 602
 603    pub fn foreground(&self) -> Rc<executor::Foreground> {
 604        self.cx.borrow().foreground().clone()
 605    }
 606
 607    pub fn background(&self) -> Arc<executor::Background> {
 608        self.cx.borrow().background().clone()
 609    }
 610
 611    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
 612    where
 613        F: FnOnce(AsyncAppContext) -> Fut,
 614        Fut: 'static + Future<Output = T>,
 615        T: 'static,
 616    {
 617        let foreground = self.foreground();
 618        let future = f(self.to_async());
 619        let cx = self.to_async();
 620        foreground.spawn(async move {
 621            let result = future.await;
 622            cx.0.borrow_mut().flush_effects();
 623            result
 624        })
 625    }
 626
 627    pub fn simulate_new_path_selection(&self, result: impl FnOnce(PathBuf) -> Option<PathBuf>) {
 628        self.foreground_platform.simulate_new_path_selection(result);
 629    }
 630
 631    pub fn did_prompt_for_new_path(&self) -> bool {
 632        self.foreground_platform.as_ref().did_prompt_for_new_path()
 633    }
 634
 635    pub fn simulate_prompt_answer(&self, window_id: usize, answer: usize) {
 636        use postage::prelude::Sink as _;
 637
 638        let mut done_tx = self
 639            .window_mut(window_id)
 640            .pending_prompts
 641            .borrow_mut()
 642            .pop_front()
 643            .expect("prompt was not called");
 644        let _ = done_tx.try_send(answer);
 645    }
 646
 647    pub fn has_pending_prompt(&self, window_id: usize) -> bool {
 648        let window = self.window_mut(window_id);
 649        let prompts = window.pending_prompts.borrow_mut();
 650        !prompts.is_empty()
 651    }
 652
 653    pub fn current_window_title(&self, window_id: usize) -> Option<String> {
 654        self.window_mut(window_id).title.clone()
 655    }
 656
 657    pub fn simulate_window_close(&self, window_id: usize) -> bool {
 658        let handler = self.window_mut(window_id).should_close_handler.take();
 659        if let Some(mut handler) = handler {
 660            let should_close = handler();
 661            self.window_mut(window_id).should_close_handler = Some(handler);
 662            should_close
 663        } else {
 664            false
 665        }
 666    }
 667
 668    pub fn simulate_window_activation(&self, to_activate: Option<usize>) {
 669        let mut handlers = BTreeMap::new();
 670        {
 671            let mut cx = self.cx.borrow_mut();
 672            for (window_id, (_, window)) in &mut cx.presenters_and_platform_windows {
 673                let window = window
 674                    .as_any_mut()
 675                    .downcast_mut::<platform::test::Window>()
 676                    .unwrap();
 677                handlers.insert(
 678                    *window_id,
 679                    mem::take(&mut window.active_status_change_handlers),
 680                );
 681            }
 682        };
 683        let mut handlers = handlers.into_iter().collect::<Vec<_>>();
 684        handlers.sort_unstable_by_key(|(window_id, _)| Some(*window_id) == to_activate);
 685
 686        for (window_id, mut window_handlers) in handlers {
 687            for window_handler in &mut window_handlers {
 688                window_handler(Some(window_id) == to_activate);
 689            }
 690
 691            self.window_mut(window_id)
 692                .active_status_change_handlers
 693                .extend(window_handlers);
 694        }
 695    }
 696
 697    pub fn is_window_edited(&self, window_id: usize) -> bool {
 698        self.window_mut(window_id).edited
 699    }
 700
 701    pub fn leak_detector(&self) -> Arc<Mutex<LeakDetector>> {
 702        self.cx.borrow().leak_detector()
 703    }
 704
 705    pub fn assert_dropped(&self, handle: impl WeakHandle) {
 706        self.cx
 707            .borrow()
 708            .leak_detector()
 709            .lock()
 710            .assert_dropped(handle.id())
 711    }
 712
 713    fn window_mut(&self, window_id: usize) -> std::cell::RefMut<platform::test::Window> {
 714        std::cell::RefMut::map(self.cx.borrow_mut(), |state| {
 715            let (_, window) = state
 716                .presenters_and_platform_windows
 717                .get_mut(&window_id)
 718                .unwrap();
 719            let test_window = window
 720                .as_any_mut()
 721                .downcast_mut::<platform::test::Window>()
 722                .unwrap();
 723            test_window
 724        })
 725    }
 726
 727    pub fn set_condition_duration(&mut self, duration: Option<Duration>) {
 728        self.condition_duration = duration;
 729    }
 730
 731    pub fn condition_duration(&self) -> Duration {
 732        self.condition_duration.unwrap_or_else(|| {
 733            if std::env::var("CI").is_ok() {
 734                Duration::from_secs(2)
 735            } else {
 736                Duration::from_millis(500)
 737            }
 738        })
 739    }
 740
 741    pub fn assert_clipboard_content(&mut self, expected_content: Option<&str>) {
 742        self.update(|cx| {
 743            let actual_content = cx.read_from_clipboard().map(|item| item.text().to_owned());
 744            let expected_content = expected_content.map(|content| content.to_owned());
 745            assert_eq!(actual_content, expected_content);
 746        })
 747    }
 748}
 749
 750impl AsyncAppContext {
 751    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
 752    where
 753        F: FnOnce(AsyncAppContext) -> Fut,
 754        Fut: 'static + Future<Output = T>,
 755        T: 'static,
 756    {
 757        self.0.borrow().foreground.spawn(f(self.clone()))
 758    }
 759
 760    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 761        callback(self.0.borrow().as_ref())
 762    }
 763
 764    pub fn update<T, F: FnOnce(&mut MutableAppContext) -> T>(&mut self, callback: F) -> T {
 765        self.0.borrow_mut().update(callback)
 766    }
 767
 768    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 769    where
 770        T: Entity,
 771        F: FnOnce(&mut ModelContext<T>) -> T,
 772    {
 773        self.update(|cx| cx.add_model(build_model))
 774    }
 775
 776    pub fn add_window<T, F>(
 777        &mut self,
 778        window_options: WindowOptions,
 779        build_root_view: F,
 780    ) -> (usize, ViewHandle<T>)
 781    where
 782        T: View,
 783        F: FnOnce(&mut ViewContext<T>) -> T,
 784    {
 785        self.update(|cx| cx.add_window(window_options, build_root_view))
 786    }
 787
 788    pub fn platform(&self) -> Arc<dyn Platform> {
 789        self.0.borrow().platform()
 790    }
 791
 792    pub fn foreground(&self) -> Rc<executor::Foreground> {
 793        self.0.borrow().foreground.clone()
 794    }
 795
 796    pub fn background(&self) -> Arc<executor::Background> {
 797        self.0.borrow().cx.background.clone()
 798    }
 799}
 800
 801impl UpdateModel for AsyncAppContext {
 802    fn update_model<E: Entity, O>(
 803        &mut self,
 804        handle: &ModelHandle<E>,
 805        update: &mut dyn FnMut(&mut E, &mut ModelContext<E>) -> O,
 806    ) -> O {
 807        self.0.borrow_mut().update_model(handle, update)
 808    }
 809}
 810
 811impl UpgradeModelHandle for AsyncAppContext {
 812    fn upgrade_model_handle<T: Entity>(
 813        &self,
 814        handle: &WeakModelHandle<T>,
 815    ) -> Option<ModelHandle<T>> {
 816        self.0.borrow().upgrade_model_handle(handle)
 817    }
 818
 819    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
 820        self.0.borrow().model_handle_is_upgradable(handle)
 821    }
 822
 823    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
 824        self.0.borrow().upgrade_any_model_handle(handle)
 825    }
 826}
 827
 828impl UpgradeViewHandle for AsyncAppContext {
 829    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
 830        self.0.borrow_mut().upgrade_view_handle(handle)
 831    }
 832
 833    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
 834        self.0.borrow_mut().upgrade_any_view_handle(handle)
 835    }
 836}
 837
 838impl ReadModelWith for AsyncAppContext {
 839    fn read_model_with<E: Entity, T>(
 840        &self,
 841        handle: &ModelHandle<E>,
 842        read: &mut dyn FnMut(&E, &AppContext) -> T,
 843    ) -> T {
 844        let cx = self.0.borrow();
 845        let cx = cx.as_ref();
 846        read(handle.read(cx), cx)
 847    }
 848}
 849
 850impl UpdateView for AsyncAppContext {
 851    fn update_view<T, S>(
 852        &mut self,
 853        handle: &ViewHandle<T>,
 854        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
 855    ) -> S
 856    where
 857        T: View,
 858    {
 859        self.0.borrow_mut().update_view(handle, update)
 860    }
 861}
 862
 863impl ReadViewWith for AsyncAppContext {
 864    fn read_view_with<V, T>(
 865        &self,
 866        handle: &ViewHandle<V>,
 867        read: &mut dyn FnMut(&V, &AppContext) -> T,
 868    ) -> T
 869    where
 870        V: View,
 871    {
 872        let cx = self.0.borrow();
 873        let cx = cx.as_ref();
 874        read(handle.read(cx), cx)
 875    }
 876}
 877
 878#[cfg(any(test, feature = "test-support"))]
 879impl UpdateModel for TestAppContext {
 880    fn update_model<T: Entity, O>(
 881        &mut self,
 882        handle: &ModelHandle<T>,
 883        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
 884    ) -> O {
 885        self.cx.borrow_mut().update_model(handle, update)
 886    }
 887}
 888
 889#[cfg(any(test, feature = "test-support"))]
 890impl ReadModelWith for TestAppContext {
 891    fn read_model_with<E: Entity, T>(
 892        &self,
 893        handle: &ModelHandle<E>,
 894        read: &mut dyn FnMut(&E, &AppContext) -> T,
 895    ) -> T {
 896        let cx = self.cx.borrow();
 897        let cx = cx.as_ref();
 898        read(handle.read(cx), cx)
 899    }
 900}
 901
 902#[cfg(any(test, feature = "test-support"))]
 903impl UpdateView for TestAppContext {
 904    fn update_view<T, S>(
 905        &mut self,
 906        handle: &ViewHandle<T>,
 907        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
 908    ) -> S
 909    where
 910        T: View,
 911    {
 912        self.cx.borrow_mut().update_view(handle, update)
 913    }
 914}
 915
 916#[cfg(any(test, feature = "test-support"))]
 917impl ReadViewWith for TestAppContext {
 918    fn read_view_with<V, T>(
 919        &self,
 920        handle: &ViewHandle<V>,
 921        read: &mut dyn FnMut(&V, &AppContext) -> T,
 922    ) -> T
 923    where
 924        V: View,
 925    {
 926        let cx = self.cx.borrow();
 927        let cx = cx.as_ref();
 928        read(handle.read(cx), cx)
 929    }
 930}
 931
 932type ActionCallback =
 933    dyn FnMut(&mut dyn AnyView, &dyn Action, &mut MutableAppContext, usize, usize);
 934type GlobalActionCallback = dyn FnMut(&dyn Action, &mut MutableAppContext);
 935
 936type SubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut MutableAppContext) -> bool>;
 937type GlobalSubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut MutableAppContext)>;
 938type ObservationCallback = Box<dyn FnMut(&mut MutableAppContext) -> bool>;
 939type FocusObservationCallback = Box<dyn FnMut(bool, &mut MutableAppContext) -> bool>;
 940type GlobalObservationCallback = Box<dyn FnMut(&mut MutableAppContext)>;
 941type ReleaseObservationCallback = Box<dyn FnOnce(&dyn Any, &mut MutableAppContext)>;
 942type ActionObservationCallback = Box<dyn FnMut(TypeId, &mut MutableAppContext)>;
 943type WindowActivationCallback = Box<dyn FnMut(bool, &mut MutableAppContext) -> bool>;
 944type WindowFullscreenCallback = Box<dyn FnMut(bool, &mut MutableAppContext) -> bool>;
 945type DeserializeActionCallback = fn(json: &str) -> anyhow::Result<Box<dyn Action>>;
 946type WindowShouldCloseSubscriptionCallback = Box<dyn FnMut(&mut MutableAppContext) -> bool>;
 947
 948pub struct MutableAppContext {
 949    weak_self: Option<rc::Weak<RefCell<Self>>>,
 950    foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 951    assets: Arc<AssetCache>,
 952    cx: AppContext,
 953    action_deserializers: HashMap<&'static str, (TypeId, DeserializeActionCallback)>,
 954    capture_actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 955    actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 956    global_actions: HashMap<TypeId, Box<GlobalActionCallback>>,
 957    keystroke_matcher: keymap::Matcher,
 958    next_entity_id: usize,
 959    next_window_id: usize,
 960    next_subscription_id: usize,
 961    frame_count: usize,
 962
 963    focus_observations: CallbackCollection<usize, FocusObservationCallback>,
 964    global_subscriptions: CallbackCollection<TypeId, GlobalSubscriptionCallback>,
 965    global_observations: CallbackCollection<TypeId, GlobalObservationCallback>,
 966    subscriptions: CallbackCollection<usize, SubscriptionCallback>,
 967    observations: CallbackCollection<usize, ObservationCallback>,
 968    window_activation_observations: CallbackCollection<usize, WindowActivationCallback>,
 969    window_fullscreen_observations: CallbackCollection<usize, WindowFullscreenCallback>,
 970
 971    release_observations: Arc<Mutex<HashMap<usize, BTreeMap<usize, ReleaseObservationCallback>>>>,
 972    action_dispatch_observations: Arc<Mutex<BTreeMap<usize, ActionObservationCallback>>>,
 973
 974    #[allow(clippy::type_complexity)]
 975    presenters_and_platform_windows:
 976        HashMap<usize, (Rc<RefCell<Presenter>>, Box<dyn platform::Window>)>,
 977    foreground: Rc<executor::Foreground>,
 978    pending_effects: VecDeque<Effect>,
 979    pending_focus_index: Option<usize>,
 980    pending_notifications: HashSet<usize>,
 981    pending_global_notifications: HashSet<TypeId>,
 982    pending_flushes: usize,
 983    flushing_effects: bool,
 984    halt_action_dispatch: bool,
 985}
 986
 987impl MutableAppContext {
 988    fn new(
 989        foreground: Rc<executor::Foreground>,
 990        background: Arc<executor::Background>,
 991        platform: Arc<dyn platform::Platform>,
 992        foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 993        font_cache: Arc<FontCache>,
 994        ref_counts: RefCounts,
 995        asset_source: impl AssetSource,
 996    ) -> Self {
 997        Self {
 998            weak_self: None,
 999            foreground_platform,
1000            assets: Arc::new(AssetCache::new(asset_source)),
1001            cx: AppContext {
1002                models: Default::default(),
1003                views: Default::default(),
1004                parents: Default::default(),
1005                windows: Default::default(),
1006                globals: Default::default(),
1007                element_states: Default::default(),
1008                ref_counts: Arc::new(Mutex::new(ref_counts)),
1009                background,
1010                font_cache,
1011                platform,
1012            },
1013            action_deserializers: Default::default(),
1014            capture_actions: Default::default(),
1015            actions: Default::default(),
1016            global_actions: Default::default(),
1017            keystroke_matcher: keymap::Matcher::default(),
1018            next_entity_id: 0,
1019            next_window_id: 0,
1020            next_subscription_id: 0,
1021            frame_count: 0,
1022            subscriptions: Default::default(),
1023            global_subscriptions: Default::default(),
1024            observations: Default::default(),
1025            focus_observations: Default::default(),
1026            release_observations: Default::default(),
1027            global_observations: Default::default(),
1028            window_activation_observations: Default::default(),
1029            window_fullscreen_observations: Default::default(),
1030            action_dispatch_observations: Default::default(),
1031            presenters_and_platform_windows: Default::default(),
1032            foreground,
1033            pending_effects: VecDeque::new(),
1034            pending_focus_index: None,
1035            pending_notifications: Default::default(),
1036            pending_global_notifications: Default::default(),
1037            pending_flushes: 0,
1038            flushing_effects: false,
1039            halt_action_dispatch: false,
1040        }
1041    }
1042
1043    pub fn upgrade(&self) -> App {
1044        App(self.weak_self.as_ref().unwrap().upgrade().unwrap())
1045    }
1046
1047    pub fn quit(&mut self) {
1048        let mut futures = Vec::new();
1049        for model_id in self.cx.models.keys().copied().collect::<Vec<_>>() {
1050            let mut model = self.cx.models.remove(&model_id).unwrap();
1051            futures.extend(model.app_will_quit(self));
1052            self.cx.models.insert(model_id, model);
1053        }
1054
1055        for view_id in self.cx.views.keys().copied().collect::<Vec<_>>() {
1056            let mut view = self.cx.views.remove(&view_id).unwrap();
1057            futures.extend(view.app_will_quit(self));
1058            self.cx.views.insert(view_id, view);
1059        }
1060
1061        self.remove_all_windows();
1062
1063        let futures = futures::future::join_all(futures);
1064        if self
1065            .background
1066            .block_with_timeout(Duration::from_millis(100), futures)
1067            .is_err()
1068        {
1069            log::error!("timed out waiting on app_will_quit");
1070        }
1071    }
1072
1073    pub fn remove_all_windows(&mut self) {
1074        for (window_id, _) in self.cx.windows.drain() {
1075            self.presenters_and_platform_windows.remove(&window_id);
1076        }
1077        self.flush_effects();
1078    }
1079
1080    pub fn platform(&self) -> Arc<dyn platform::Platform> {
1081        self.cx.platform.clone()
1082    }
1083
1084    pub fn font_cache(&self) -> &Arc<FontCache> {
1085        &self.cx.font_cache
1086    }
1087
1088    pub fn foreground(&self) -> &Rc<executor::Foreground> {
1089        &self.foreground
1090    }
1091
1092    pub fn background(&self) -> &Arc<executor::Background> {
1093        &self.cx.background
1094    }
1095
1096    pub fn debug_elements(&self, window_id: usize) -> Option<crate::json::Value> {
1097        self.presenters_and_platform_windows
1098            .get(&window_id)
1099            .and_then(|(presenter, _)| presenter.borrow().debug_elements(self))
1100    }
1101
1102    pub fn deserialize_action(
1103        &self,
1104        name: &str,
1105        argument: Option<&str>,
1106    ) -> Result<Box<dyn Action>> {
1107        let callback = self
1108            .action_deserializers
1109            .get(name)
1110            .ok_or_else(|| anyhow!("unknown action {}", name))?
1111            .1;
1112        callback(argument.unwrap_or("{}"))
1113            .with_context(|| format!("invalid data for action {}", name))
1114    }
1115
1116    pub fn add_action<A, V, F>(&mut self, handler: F)
1117    where
1118        A: Action,
1119        V: View,
1120        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
1121    {
1122        self.add_action_internal(handler, false)
1123    }
1124
1125    pub fn capture_action<A, V, F>(&mut self, handler: F)
1126    where
1127        A: Action,
1128        V: View,
1129        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
1130    {
1131        self.add_action_internal(handler, true)
1132    }
1133
1134    fn add_action_internal<A, V, F>(&mut self, mut handler: F, capture: bool)
1135    where
1136        A: Action,
1137        V: View,
1138        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
1139    {
1140        let handler = Box::new(
1141            move |view: &mut dyn AnyView,
1142                  action: &dyn Action,
1143                  cx: &mut MutableAppContext,
1144                  window_id: usize,
1145                  view_id: usize| {
1146                let action = action.as_any().downcast_ref().unwrap();
1147                let mut cx = ViewContext::new(cx, window_id, view_id);
1148                handler(
1149                    view.as_any_mut()
1150                        .downcast_mut()
1151                        .expect("downcast is type safe"),
1152                    action,
1153                    &mut cx,
1154                );
1155            },
1156        );
1157
1158        self.action_deserializers
1159            .entry(A::qualified_name())
1160            .or_insert((TypeId::of::<A>(), A::from_json_str));
1161
1162        let actions = if capture {
1163            &mut self.capture_actions
1164        } else {
1165            &mut self.actions
1166        };
1167
1168        actions
1169            .entry(TypeId::of::<V>())
1170            .or_default()
1171            .entry(TypeId::of::<A>())
1172            .or_default()
1173            .push(handler);
1174    }
1175
1176    pub fn add_async_action<A, V, F>(&mut self, mut handler: F)
1177    where
1178        A: Action,
1179        V: View,
1180        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> Option<Task<Result<()>>>,
1181    {
1182        self.add_action(move |view, action, cx| {
1183            if let Some(task) = handler(view, action, cx) {
1184                task.detach_and_log_err(cx);
1185            }
1186        })
1187    }
1188
1189    pub fn add_global_action<A, F>(&mut self, mut handler: F)
1190    where
1191        A: Action,
1192        F: 'static + FnMut(&A, &mut MutableAppContext),
1193    {
1194        let handler = Box::new(move |action: &dyn Action, cx: &mut MutableAppContext| {
1195            let action = action.as_any().downcast_ref().unwrap();
1196            handler(action, cx);
1197        });
1198
1199        self.action_deserializers
1200            .entry(A::qualified_name())
1201            .or_insert((TypeId::of::<A>(), A::from_json_str));
1202
1203        if self
1204            .global_actions
1205            .insert(TypeId::of::<A>(), handler)
1206            .is_some()
1207        {
1208            panic!(
1209                "registered multiple global handlers for {}",
1210                type_name::<A>()
1211            );
1212        }
1213    }
1214
1215    pub fn window_ids(&self) -> impl Iterator<Item = usize> + '_ {
1216        self.cx.windows.keys().cloned()
1217    }
1218
1219    pub fn activate_window(&self, window_id: usize) {
1220        if let Some((_, window)) = self.presenters_and_platform_windows.get(&window_id) {
1221            window.activate()
1222        }
1223    }
1224
1225    pub fn root_view<T: View>(&self, window_id: usize) -> Option<ViewHandle<T>> {
1226        self.cx
1227            .windows
1228            .get(&window_id)
1229            .and_then(|window| window.root_view.clone().downcast::<T>())
1230    }
1231
1232    pub fn window_is_active(&self, window_id: usize) -> bool {
1233        self.cx
1234            .windows
1235            .get(&window_id)
1236            .map_or(false, |window| window.is_active)
1237    }
1238
1239    pub fn window_is_fullscreen(&self, window_id: usize) -> bool {
1240        self.cx
1241            .windows
1242            .get(&window_id)
1243            .map_or(false, |window| window.is_fullscreen)
1244    }
1245
1246    pub fn render_view(&mut self, params: RenderParams) -> Result<ElementBox> {
1247        let window_id = params.window_id;
1248        let view_id = params.view_id;
1249        let mut view = self
1250            .cx
1251            .views
1252            .remove(&(window_id, view_id))
1253            .ok_or_else(|| anyhow!("view not found"))?;
1254        let element = view.render(params, self);
1255        self.cx.views.insert((window_id, view_id), view);
1256        Ok(element)
1257    }
1258
1259    pub fn render_views(
1260        &mut self,
1261        window_id: usize,
1262        titlebar_height: f32,
1263    ) -> HashMap<usize, ElementBox> {
1264        self.start_frame();
1265        #[allow(clippy::needless_collect)]
1266        let view_ids = self
1267            .views
1268            .keys()
1269            .filter_map(|(win_id, view_id)| {
1270                if *win_id == window_id {
1271                    Some(*view_id)
1272                } else {
1273                    None
1274                }
1275            })
1276            .collect::<Vec<_>>();
1277
1278        view_ids
1279            .into_iter()
1280            .map(|view_id| {
1281                (
1282                    view_id,
1283                    self.render_view(RenderParams {
1284                        window_id,
1285                        view_id,
1286                        titlebar_height,
1287                        hovered_region_ids: Default::default(),
1288                        clicked_region_ids: None,
1289                        refreshing: false,
1290                    })
1291                    .unwrap(),
1292                )
1293            })
1294            .collect()
1295    }
1296
1297    pub(crate) fn start_frame(&mut self) {
1298        self.frame_count += 1;
1299    }
1300
1301    pub fn update<T, F: FnOnce(&mut Self) -> T>(&mut self, callback: F) -> T {
1302        self.pending_flushes += 1;
1303        let result = callback(self);
1304        self.flush_effects();
1305        result
1306    }
1307
1308    pub fn set_menus(&mut self, menus: Vec<Menu>) {
1309        self.foreground_platform
1310            .set_menus(menus, &self.keystroke_matcher);
1311    }
1312
1313    fn show_character_palette(&self, window_id: usize) {
1314        let (_, window) = &self.presenters_and_platform_windows[&window_id];
1315        window.show_character_palette();
1316    }
1317
1318    pub fn minimize_window(&self, window_id: usize) {
1319        let (_, window) = &self.presenters_and_platform_windows[&window_id];
1320        window.minimize();
1321    }
1322
1323    pub fn zoom_window(&self, window_id: usize) {
1324        let (_, window) = &self.presenters_and_platform_windows[&window_id];
1325        window.zoom();
1326    }
1327
1328    pub fn toggle_window_full_screen(&self, window_id: usize) {
1329        let (_, window) = &self.presenters_and_platform_windows[&window_id];
1330        window.toggle_full_screen();
1331    }
1332
1333    fn prompt(
1334        &self,
1335        window_id: usize,
1336        level: PromptLevel,
1337        msg: &str,
1338        answers: &[&str],
1339    ) -> oneshot::Receiver<usize> {
1340        let (_, window) = &self.presenters_and_platform_windows[&window_id];
1341        window.prompt(level, msg, answers)
1342    }
1343
1344    pub fn prompt_for_paths(
1345        &self,
1346        options: PathPromptOptions,
1347    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
1348        self.foreground_platform.prompt_for_paths(options)
1349    }
1350
1351    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
1352        self.foreground_platform.prompt_for_new_path(directory)
1353    }
1354
1355    pub fn emit_global<E: Any>(&mut self, payload: E) {
1356        self.pending_effects.push_back(Effect::GlobalEvent {
1357            payload: Box::new(payload),
1358        });
1359    }
1360
1361    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
1362    where
1363        E: Entity,
1364        E::Event: 'static,
1365        H: Handle<E>,
1366        F: 'static + FnMut(H, &E::Event, &mut Self),
1367    {
1368        self.subscribe_internal(handle, move |handle, event, cx| {
1369            callback(handle, event, cx);
1370            true
1371        })
1372    }
1373
1374    pub fn subscribe_global<E, F>(&mut self, mut callback: F) -> Subscription
1375    where
1376        E: Any,
1377        F: 'static + FnMut(&E, &mut Self),
1378    {
1379        let subscription_id = post_inc(&mut self.next_subscription_id);
1380        let type_id = TypeId::of::<E>();
1381        self.pending_effects.push_back(Effect::GlobalSubscription {
1382            type_id,
1383            subscription_id,
1384            callback: Box::new(move |payload, cx| {
1385                let payload = payload.downcast_ref().expect("downcast is type safe");
1386                callback(payload, cx)
1387            }),
1388        });
1389
1390        Subscription::GlobalSubscription {
1391            id: subscription_id,
1392            type_id,
1393            subscriptions: Some(self.global_subscriptions.downgrade()),
1394        }
1395    }
1396
1397    pub fn observe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
1398    where
1399        E: Entity,
1400        E::Event: 'static,
1401        H: Handle<E>,
1402        F: 'static + FnMut(H, &mut Self),
1403    {
1404        self.observe_internal(handle, move |handle, cx| {
1405            callback(handle, cx);
1406            true
1407        })
1408    }
1409
1410    pub fn subscribe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
1411    where
1412        E: Entity,
1413        E::Event: 'static,
1414        H: Handle<E>,
1415        F: 'static + FnMut(H, &E::Event, &mut Self) -> bool,
1416    {
1417        let subscription_id = post_inc(&mut self.next_subscription_id);
1418        let emitter = handle.downgrade();
1419        self.pending_effects.push_back(Effect::Subscription {
1420            entity_id: handle.id(),
1421            subscription_id,
1422            callback: Box::new(move |payload, cx| {
1423                if let Some(emitter) = H::upgrade_from(&emitter, cx.as_ref()) {
1424                    let payload = payload.downcast_ref().expect("downcast is type safe");
1425                    callback(emitter, payload, cx)
1426                } else {
1427                    false
1428                }
1429            }),
1430        });
1431        Subscription::Subscription {
1432            id: subscription_id,
1433            entity_id: handle.id(),
1434            subscriptions: Some(self.subscriptions.downgrade()),
1435        }
1436    }
1437
1438    fn observe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
1439    where
1440        E: Entity,
1441        E::Event: 'static,
1442        H: Handle<E>,
1443        F: 'static + FnMut(H, &mut Self) -> bool,
1444    {
1445        let subscription_id = post_inc(&mut self.next_subscription_id);
1446        let observed = handle.downgrade();
1447        let entity_id = handle.id();
1448        self.pending_effects.push_back(Effect::Observation {
1449            entity_id,
1450            subscription_id,
1451            callback: Box::new(move |cx| {
1452                if let Some(observed) = H::upgrade_from(&observed, cx) {
1453                    callback(observed, cx)
1454                } else {
1455                    false
1456                }
1457            }),
1458        });
1459        Subscription::Observation {
1460            id: subscription_id,
1461            entity_id,
1462            observations: Some(self.observations.downgrade()),
1463        }
1464    }
1465
1466    fn observe_focus<F, V>(&mut self, handle: &ViewHandle<V>, mut callback: F) -> Subscription
1467    where
1468        F: 'static + FnMut(ViewHandle<V>, bool, &mut MutableAppContext) -> bool,
1469        V: View,
1470    {
1471        let subscription_id = post_inc(&mut self.next_subscription_id);
1472        let observed = handle.downgrade();
1473        let view_id = handle.id();
1474
1475        self.pending_effects.push_back(Effect::FocusObservation {
1476            view_id,
1477            subscription_id,
1478            callback: Box::new(move |focused, cx| {
1479                if let Some(observed) = observed.upgrade(cx) {
1480                    callback(observed, focused, cx)
1481                } else {
1482                    false
1483                }
1484            }),
1485        });
1486
1487        Subscription::FocusObservation {
1488            id: subscription_id,
1489            view_id,
1490            observations: Some(self.focus_observations.downgrade()),
1491        }
1492    }
1493
1494    pub fn observe_global<G, F>(&mut self, mut observe: F) -> Subscription
1495    where
1496        G: Any,
1497        F: 'static + FnMut(&mut MutableAppContext),
1498    {
1499        let type_id = TypeId::of::<G>();
1500        let id = post_inc(&mut self.next_subscription_id);
1501
1502        self.global_observations.add_callback(
1503            type_id,
1504            id,
1505            Box::new(move |cx: &mut MutableAppContext| observe(cx)),
1506        );
1507
1508        Subscription::GlobalObservation {
1509            id,
1510            type_id,
1511            observations: Some(self.global_observations.downgrade()),
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(self.window_activation_observations.downgrade()),
1570        }
1571    }
1572
1573    fn observe_fullscreen<F>(&mut self, window_id: usize, callback: F) -> Subscription
1574    where
1575        F: 'static + FnMut(bool, &mut MutableAppContext) -> bool,
1576    {
1577        let subscription_id = post_inc(&mut self.next_subscription_id);
1578        self.pending_effects
1579            .push_back(Effect::WindowFullscreenObservation {
1580                window_id,
1581                subscription_id,
1582                callback: Box::new(callback),
1583            });
1584        Subscription::WindowFullscreenObservation {
1585            id: subscription_id,
1586            window_id,
1587            observations: Some(self.window_activation_observations.downgrade()),
1588        }
1589    }
1590
1591    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut MutableAppContext)) {
1592        self.pending_effects.push_back(Effect::Deferred {
1593            callback: Box::new(callback),
1594            after_window_update: false,
1595        })
1596    }
1597
1598    pub fn after_window_update(&mut self, callback: impl 'static + FnOnce(&mut MutableAppContext)) {
1599        self.pending_effects.push_back(Effect::Deferred {
1600            callback: Box::new(callback),
1601            after_window_update: true,
1602        })
1603    }
1604
1605    pub(crate) fn notify_model(&mut self, model_id: usize) {
1606        if self.pending_notifications.insert(model_id) {
1607            self.pending_effects
1608                .push_back(Effect::ModelNotification { model_id });
1609        }
1610    }
1611
1612    pub(crate) fn notify_view(&mut self, window_id: usize, view_id: usize) {
1613        if self.pending_notifications.insert(view_id) {
1614            self.pending_effects
1615                .push_back(Effect::ViewNotification { window_id, view_id });
1616        }
1617    }
1618
1619    pub(crate) fn notify_global(&mut self, type_id: TypeId) {
1620        if self.pending_global_notifications.insert(type_id) {
1621            self.pending_effects
1622                .push_back(Effect::GlobalNotification { type_id });
1623        }
1624    }
1625
1626    pub(crate) fn name_for_view(&self, window_id: usize, view_id: usize) -> Option<&str> {
1627        self.views
1628            .get(&(window_id, view_id))
1629            .map(|view| view.ui_name())
1630    }
1631
1632    pub fn all_action_names<'a>(&'a self) -> impl Iterator<Item = &'static str> + 'a {
1633        self.action_deserializers.keys().copied()
1634    }
1635
1636    pub fn available_actions(
1637        &self,
1638        window_id: usize,
1639        view_id: usize,
1640    ) -> impl Iterator<Item = (&'static str, Box<dyn Action>, SmallVec<[&Binding; 1]>)> {
1641        let mut action_types: HashSet<_> = self.global_actions.keys().copied().collect();
1642
1643        for view_id in self.parents(window_id, view_id) {
1644            if let Some(view) = self.views.get(&(window_id, view_id)) {
1645                let view_type = view.as_any().type_id();
1646                if let Some(actions) = self.actions.get(&view_type) {
1647                    action_types.extend(actions.keys().copied());
1648                }
1649            }
1650        }
1651
1652        self.action_deserializers
1653            .iter()
1654            .filter_map(move |(name, (type_id, deserialize))| {
1655                if action_types.contains(type_id) {
1656                    Some((
1657                        *name,
1658                        deserialize("{}").ok()?,
1659                        self.keystroke_matcher
1660                            .bindings_for_action_type(*type_id)
1661                            .collect(),
1662                    ))
1663                } else {
1664                    None
1665                }
1666            })
1667    }
1668
1669    pub fn is_action_available(&self, action: &dyn Action) -> bool {
1670        let action_type = action.as_any().type_id();
1671        if let Some(window_id) = self.cx.platform.key_window_id() {
1672            if let Some(focused_view_id) = self.focused_view_id(window_id) {
1673                for view_id in self.parents(window_id, focused_view_id) {
1674                    if let Some(view) = self.views.get(&(window_id, view_id)) {
1675                        let view_type = view.as_any().type_id();
1676                        if let Some(actions) = self.actions.get(&view_type) {
1677                            if actions.contains_key(&action_type) {
1678                                return true;
1679                            }
1680                        }
1681                    }
1682                }
1683            }
1684        }
1685        self.global_actions.contains_key(&action_type)
1686    }
1687
1688    /// Return keystrokes that would dispatch the given action closest to the focused view, if there are any.
1689    pub(crate) fn keystrokes_for_action(
1690        &self,
1691        window_id: usize,
1692        dispatch_path: &[usize],
1693        action: &dyn Action,
1694    ) -> Option<SmallVec<[Keystroke; 2]>> {
1695        for view_id in dispatch_path.iter().rev() {
1696            let view = self
1697                .cx
1698                .views
1699                .get(&(window_id, *view_id))
1700                .expect("view in responder chain does not exist");
1701            let cx = view.keymap_context(self.as_ref());
1702            let keystrokes = self.keystroke_matcher.keystrokes_for_action(action, &cx);
1703            if keystrokes.is_some() {
1704                return keystrokes;
1705            }
1706        }
1707
1708        None
1709    }
1710
1711    // Traverses the parent tree. Walks down the tree toward the passed
1712    // view calling visit with true. Then walks back up the tree calling visit with false.
1713    // If `visit` returns false this function will immediately return.
1714    // Returns a bool indicating if the traversal was completed early.
1715    fn visit_dispatch_path(
1716        &mut self,
1717        window_id: usize,
1718        view_id: usize,
1719        mut visit: impl FnMut(usize, bool, &mut MutableAppContext) -> bool,
1720    ) -> bool {
1721        // List of view ids from the leaf to the root of the window
1722        let path = self.parents(window_id, view_id).collect::<Vec<_>>();
1723
1724        // Walk down from the root to the leaf calling visit with capture_phase = true
1725        for view_id in path.iter().rev() {
1726            if !visit(*view_id, true, self) {
1727                return false;
1728            }
1729        }
1730
1731        // Walk up from the leaf to the root calling visit with capture_phase = false
1732        for view_id in path.iter() {
1733            if !visit(*view_id, false, self) {
1734                return false;
1735            }
1736        }
1737
1738        true
1739    }
1740
1741    // Returns an iterator over all of the view ids from the passed view up to the root of the window
1742    // Includes the passed view itself
1743    fn parents(&self, window_id: usize, mut view_id: usize) -> impl Iterator<Item = usize> + '_ {
1744        std::iter::once(view_id)
1745            .into_iter()
1746            .chain(std::iter::from_fn(move || {
1747                if let Some(ParentId::View(parent_id)) = self.parents.get(&(window_id, view_id)) {
1748                    view_id = *parent_id;
1749                    Some(view_id)
1750                } else {
1751                    None
1752                }
1753            }))
1754    }
1755
1756    fn actions_mut(
1757        &mut self,
1758        capture_phase: bool,
1759    ) -> &mut HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>> {
1760        if capture_phase {
1761            &mut self.capture_actions
1762        } else {
1763            &mut self.actions
1764        }
1765    }
1766
1767    pub fn dispatch_global_action<A: Action>(&mut self, action: A) {
1768        self.dispatch_global_action_any(&action);
1769    }
1770
1771    fn dispatch_global_action_any(&mut self, action: &dyn Action) -> bool {
1772        self.update(|this| {
1773            if let Some((name, mut handler)) = this.global_actions.remove_entry(&action.id()) {
1774                handler(action, this);
1775                this.global_actions.insert(name, handler);
1776                true
1777            } else {
1778                false
1779            }
1780        })
1781    }
1782
1783    pub fn add_bindings<T: IntoIterator<Item = keymap::Binding>>(&mut self, bindings: T) {
1784        self.keystroke_matcher.add_bindings(bindings);
1785    }
1786
1787    pub fn clear_bindings(&mut self) {
1788        self.keystroke_matcher.clear_bindings();
1789    }
1790
1791    pub fn dispatch_keystroke(&mut self, window_id: usize, keystroke: &Keystroke) -> bool {
1792        let mut pending = false;
1793
1794        if let Some(focused_view_id) = self.focused_view_id(window_id) {
1795            for view_id in self.parents(window_id, focused_view_id).collect::<Vec<_>>() {
1796                let keymap_context = self
1797                    .cx
1798                    .views
1799                    .get(&(window_id, view_id))
1800                    .unwrap()
1801                    .keymap_context(self.as_ref());
1802
1803                match self.keystroke_matcher.push_keystroke(
1804                    keystroke.clone(),
1805                    view_id,
1806                    &keymap_context,
1807                ) {
1808                    MatchResult::None => {}
1809                    MatchResult::Pending => pending = true,
1810                    MatchResult::Action(action) => {
1811                        if self.handle_dispatch_action_from_effect(
1812                            window_id,
1813                            Some(view_id),
1814                            action.as_ref(),
1815                        ) {
1816                            self.keystroke_matcher.clear_pending();
1817                            return true;
1818                        }
1819                    }
1820                }
1821            }
1822        }
1823
1824        pending
1825    }
1826
1827    pub fn default_global<T: 'static + Default>(&mut self) -> &T {
1828        let type_id = TypeId::of::<T>();
1829        self.update(|this| {
1830            if let Entry::Vacant(entry) = this.cx.globals.entry(type_id) {
1831                entry.insert(Box::new(T::default()));
1832                this.notify_global(type_id);
1833            }
1834        });
1835        self.globals.get(&type_id).unwrap().downcast_ref().unwrap()
1836    }
1837
1838    pub fn set_global<T: 'static>(&mut self, state: T) {
1839        self.update(|this| {
1840            let type_id = TypeId::of::<T>();
1841            this.cx.globals.insert(type_id, Box::new(state));
1842            this.notify_global(type_id);
1843        });
1844    }
1845
1846    pub fn update_default_global<T, F, U>(&mut self, update: F) -> U
1847    where
1848        T: 'static + Default,
1849        F: FnOnce(&mut T, &mut MutableAppContext) -> U,
1850    {
1851        self.update(|this| {
1852            let type_id = TypeId::of::<T>();
1853            let mut state = this
1854                .cx
1855                .globals
1856                .remove(&type_id)
1857                .unwrap_or_else(|| Box::new(T::default()));
1858            let result = update(state.downcast_mut().unwrap(), this);
1859            this.cx.globals.insert(type_id, state);
1860            this.notify_global(type_id);
1861            result
1862        })
1863    }
1864
1865    pub fn update_global<T, F, U>(&mut self, update: F) -> U
1866    where
1867        T: 'static,
1868        F: FnOnce(&mut T, &mut MutableAppContext) -> U,
1869    {
1870        self.update(|this| {
1871            let type_id = TypeId::of::<T>();
1872            if let Some(mut state) = this.cx.globals.remove(&type_id) {
1873                let result = update(state.downcast_mut().unwrap(), this);
1874                this.cx.globals.insert(type_id, state);
1875                this.notify_global(type_id);
1876                result
1877            } else {
1878                panic!("No global added for {}", std::any::type_name::<T>());
1879            }
1880        })
1881    }
1882
1883    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
1884    where
1885        T: Entity,
1886        F: FnOnce(&mut ModelContext<T>) -> T,
1887    {
1888        self.update(|this| {
1889            let model_id = post_inc(&mut this.next_entity_id);
1890            let handle = ModelHandle::new(model_id, &this.cx.ref_counts);
1891            let mut cx = ModelContext::new(this, model_id);
1892            let model = build_model(&mut cx);
1893            this.cx.models.insert(model_id, Box::new(model));
1894            handle
1895        })
1896    }
1897
1898    pub fn add_window<T, F>(
1899        &mut self,
1900        window_options: WindowOptions,
1901        build_root_view: F,
1902    ) -> (usize, ViewHandle<T>)
1903    where
1904        T: View,
1905        F: FnOnce(&mut ViewContext<T>) -> T,
1906    {
1907        self.update(|this| {
1908            let window_id = post_inc(&mut this.next_window_id);
1909            let root_view = this
1910                .build_and_insert_view(window_id, ParentId::Root, |cx| Some(build_root_view(cx)))
1911                .unwrap();
1912            this.cx.windows.insert(
1913                window_id,
1914                Window {
1915                    root_view: root_view.clone().into(),
1916                    focused_view_id: Some(root_view.id()),
1917                    is_active: false,
1918                    invalidation: None,
1919                    is_fullscreen: false,
1920                },
1921            );
1922            root_view.update(this, |view, cx| view.on_focus_in(cx.handle().into(), cx));
1923            this.open_platform_window(window_id, window_options);
1924
1925            (window_id, root_view)
1926        })
1927    }
1928
1929    pub fn replace_root_view<T, F>(&mut self, window_id: usize, build_root_view: F) -> ViewHandle<T>
1930    where
1931        T: View,
1932        F: FnOnce(&mut ViewContext<T>) -> T,
1933    {
1934        self.update(|this| {
1935            let root_view = this
1936                .build_and_insert_view(window_id, ParentId::Root, |cx| Some(build_root_view(cx)))
1937                .unwrap();
1938            let window = this.cx.windows.get_mut(&window_id).unwrap();
1939            window.root_view = root_view.clone().into();
1940            window.focused_view_id = Some(root_view.id());
1941            root_view
1942        })
1943    }
1944
1945    pub fn remove_window(&mut self, window_id: usize) {
1946        self.cx.windows.remove(&window_id);
1947        self.presenters_and_platform_windows.remove(&window_id);
1948        self.flush_effects();
1949    }
1950
1951    fn open_platform_window(&mut self, window_id: usize, window_options: WindowOptions) {
1952        let mut window =
1953            self.cx
1954                .platform
1955                .open_window(window_id, window_options, self.foreground.clone());
1956        let presenter = Rc::new(RefCell::new(
1957            self.build_presenter(window_id, window.titlebar_height()),
1958        ));
1959
1960        {
1961            let mut app = self.upgrade();
1962            let presenter = Rc::downgrade(&presenter);
1963            window.on_event(Box::new(move |event| {
1964                app.update(|cx| {
1965                    if let Some(presenter) = presenter.upgrade() {
1966                        if let Event::KeyDown(KeyDownEvent { keystroke, .. }) = &event {
1967                            if cx.dispatch_keystroke(window_id, keystroke) {
1968                                return true;
1969                            }
1970                        }
1971
1972                        presenter.borrow_mut().dispatch_event(event, false, cx)
1973                    } else {
1974                        false
1975                    }
1976                })
1977            }));
1978        }
1979
1980        {
1981            let mut app = self.upgrade();
1982            window.on_active_status_change(Box::new(move |is_active| {
1983                app.update(|cx| cx.window_changed_active_status(window_id, is_active))
1984            }));
1985        }
1986
1987        {
1988            let mut app = self.upgrade();
1989            window.on_resize(Box::new(move || {
1990                app.update(|cx| cx.window_was_resized(window_id))
1991            }));
1992        }
1993
1994        {
1995            let mut app = self.upgrade();
1996            window.on_fullscreen(Box::new(move |is_fullscreen| {
1997                app.update(|cx| cx.window_was_fullscreen_changed(window_id, is_fullscreen))
1998            }));
1999        }
2000
2001        {
2002            let mut app = self.upgrade();
2003            window.on_close(Box::new(move || {
2004                app.update(|cx| cx.remove_window(window_id));
2005            }));
2006        }
2007
2008        window.set_input_handler(Box::new(WindowInputHandler {
2009            app: self.upgrade().0,
2010            window_id,
2011        }));
2012
2013        let scene =
2014            presenter
2015                .borrow_mut()
2016                .build_scene(window.size(), window.scale_factor(), false, self);
2017        window.present_scene(scene);
2018        self.presenters_and_platform_windows
2019            .insert(window_id, (presenter.clone(), window));
2020    }
2021
2022    pub fn build_presenter(&mut self, window_id: usize, titlebar_height: f32) -> Presenter {
2023        Presenter::new(
2024            window_id,
2025            titlebar_height,
2026            self.cx.font_cache.clone(),
2027            TextLayoutCache::new(self.cx.platform.fonts()),
2028            self.assets.clone(),
2029            self,
2030        )
2031    }
2032
2033    pub fn add_view<T, F>(
2034        &mut self,
2035        parent_handle: impl Into<AnyViewHandle>,
2036        build_view: F,
2037    ) -> ViewHandle<T>
2038    where
2039        T: View,
2040        F: FnOnce(&mut ViewContext<T>) -> T,
2041    {
2042        let parent_handle = parent_handle.into();
2043        self.build_and_insert_view(
2044            parent_handle.window_id,
2045            ParentId::View(parent_handle.view_id),
2046            |cx| Some(build_view(cx)),
2047        )
2048        .unwrap()
2049    }
2050
2051    pub fn add_option_view<T, F>(
2052        &mut self,
2053        parent_handle: impl Into<AnyViewHandle>,
2054        build_view: F,
2055    ) -> Option<ViewHandle<T>>
2056    where
2057        T: View,
2058        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
2059    {
2060        let parent_handle = parent_handle.into();
2061        self.build_and_insert_view(
2062            parent_handle.window_id,
2063            ParentId::View(parent_handle.view_id),
2064            build_view,
2065        )
2066    }
2067
2068    pub(crate) fn build_and_insert_view<T, F>(
2069        &mut self,
2070        window_id: usize,
2071        parent_id: ParentId,
2072        build_view: F,
2073    ) -> Option<ViewHandle<T>>
2074    where
2075        T: View,
2076        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
2077    {
2078        self.update(|this| {
2079            let view_id = post_inc(&mut this.next_entity_id);
2080            let mut cx = ViewContext::new(this, window_id, view_id);
2081            let handle = if let Some(view) = build_view(&mut cx) {
2082                this.cx.views.insert((window_id, view_id), Box::new(view));
2083                this.cx.parents.insert((window_id, view_id), parent_id);
2084                if let Some(window) = this.cx.windows.get_mut(&window_id) {
2085                    window
2086                        .invalidation
2087                        .get_or_insert_with(Default::default)
2088                        .updated
2089                        .insert(view_id);
2090                }
2091                Some(ViewHandle::new(window_id, view_id, &this.cx.ref_counts))
2092            } else {
2093                None
2094            };
2095            handle
2096        })
2097    }
2098
2099    fn remove_dropped_entities(&mut self) {
2100        loop {
2101            let (dropped_models, dropped_views, dropped_element_states) =
2102                self.cx.ref_counts.lock().take_dropped();
2103            if dropped_models.is_empty()
2104                && dropped_views.is_empty()
2105                && dropped_element_states.is_empty()
2106            {
2107                break;
2108            }
2109
2110            for model_id in dropped_models {
2111                self.subscriptions.remove(model_id);
2112                self.observations.remove(model_id);
2113                let mut model = self.cx.models.remove(&model_id).unwrap();
2114                model.release(self);
2115                self.pending_effects
2116                    .push_back(Effect::ModelRelease { model_id, model });
2117            }
2118
2119            for (window_id, view_id) in dropped_views {
2120                self.subscriptions.remove(view_id);
2121                self.observations.remove(view_id);
2122                let mut view = self.cx.views.remove(&(window_id, view_id)).unwrap();
2123                view.release(self);
2124                let change_focus_to = self.cx.windows.get_mut(&window_id).and_then(|window| {
2125                    window
2126                        .invalidation
2127                        .get_or_insert_with(Default::default)
2128                        .removed
2129                        .push(view_id);
2130                    if window.focused_view_id == Some(view_id) {
2131                        Some(window.root_view.id())
2132                    } else {
2133                        None
2134                    }
2135                });
2136                self.cx.parents.remove(&(window_id, view_id));
2137
2138                if let Some(view_id) = change_focus_to {
2139                    self.handle_focus_effect(window_id, Some(view_id));
2140                }
2141
2142                self.pending_effects
2143                    .push_back(Effect::ViewRelease { view_id, view });
2144            }
2145
2146            for key in dropped_element_states {
2147                self.cx.element_states.remove(&key);
2148            }
2149        }
2150    }
2151
2152    fn flush_effects(&mut self) {
2153        self.pending_flushes = self.pending_flushes.saturating_sub(1);
2154        let mut after_window_update_callbacks = Vec::new();
2155
2156        if !self.flushing_effects && self.pending_flushes == 0 {
2157            self.flushing_effects = true;
2158
2159            let mut refreshing = false;
2160            loop {
2161                if let Some(effect) = self.pending_effects.pop_front() {
2162                    if let Some(pending_focus_index) = self.pending_focus_index.as_mut() {
2163                        *pending_focus_index = pending_focus_index.saturating_sub(1);
2164                    }
2165                    match effect {
2166                        Effect::Subscription {
2167                            entity_id,
2168                            subscription_id,
2169                            callback,
2170                        } => self.subscriptions.add_or_remove_callback(
2171                            entity_id,
2172                            subscription_id,
2173                            callback,
2174                        ),
2175
2176                        Effect::Event { entity_id, payload } => {
2177                            let mut subscriptions = self.subscriptions.clone();
2178                            subscriptions.emit_and_cleanup(entity_id, self, |callback, this| {
2179                                callback(payload.as_ref(), this)
2180                            })
2181                        }
2182
2183                        Effect::GlobalSubscription {
2184                            type_id,
2185                            subscription_id,
2186                            callback,
2187                        } => self.global_subscriptions.add_or_remove_callback(
2188                            type_id,
2189                            subscription_id,
2190                            callback,
2191                        ),
2192
2193                        Effect::GlobalEvent { payload } => self.emit_global_event(payload),
2194
2195                        Effect::Observation {
2196                            entity_id,
2197                            subscription_id,
2198                            callback,
2199                        } => self.observations.add_or_remove_callback(
2200                            entity_id,
2201                            subscription_id,
2202                            callback,
2203                        ),
2204
2205                        Effect::ModelNotification { model_id } => {
2206                            let mut observations = self.observations.clone();
2207                            observations
2208                                .emit_and_cleanup(model_id, self, |callback, this| callback(this));
2209                        }
2210
2211                        Effect::ViewNotification { window_id, view_id } => {
2212                            self.handle_view_notification_effect(window_id, view_id)
2213                        }
2214
2215                        Effect::GlobalNotification { type_id } => {
2216                            let mut subscriptions = self.global_observations.clone();
2217                            subscriptions.emit_and_cleanup(type_id, self, |callback, this| {
2218                                callback(this);
2219                                true
2220                            });
2221                        }
2222
2223                        Effect::Deferred {
2224                            callback,
2225                            after_window_update,
2226                        } => {
2227                            if after_window_update {
2228                                after_window_update_callbacks.push(callback);
2229                            } else {
2230                                callback(self)
2231                            }
2232                        }
2233
2234                        Effect::ModelRelease { model_id, model } => {
2235                            self.handle_entity_release_effect(model_id, model.as_any())
2236                        }
2237
2238                        Effect::ViewRelease { view_id, view } => {
2239                            self.handle_entity_release_effect(view_id, view.as_any())
2240                        }
2241
2242                        Effect::Focus { window_id, view_id } => {
2243                            self.handle_focus_effect(window_id, view_id);
2244                        }
2245
2246                        Effect::FocusObservation {
2247                            view_id,
2248                            subscription_id,
2249                            callback,
2250                        } => {
2251                            self.focus_observations.add_or_remove_callback(
2252                                view_id,
2253                                subscription_id,
2254                                callback,
2255                            );
2256                        }
2257
2258                        Effect::ResizeWindow { window_id } => {
2259                            if let Some(window) = self.cx.windows.get_mut(&window_id) {
2260                                window
2261                                    .invalidation
2262                                    .get_or_insert(WindowInvalidation::default());
2263                            }
2264                        }
2265
2266                        Effect::WindowActivationObservation {
2267                            window_id,
2268                            subscription_id,
2269                            callback,
2270                        } => self.window_activation_observations.add_or_remove_callback(
2271                            window_id,
2272                            subscription_id,
2273                            callback,
2274                        ),
2275
2276                        Effect::ActivateWindow {
2277                            window_id,
2278                            is_active,
2279                        } => self.handle_window_activation_effect(window_id, is_active),
2280
2281                        Effect::WindowFullscreenObservation {
2282                            window_id,
2283                            subscription_id,
2284                            callback,
2285                        } => self.window_fullscreen_observations.add_or_remove_callback(
2286                            window_id,
2287                            subscription_id,
2288                            callback,
2289                        ),
2290
2291                        Effect::FullscreenWindow {
2292                            window_id,
2293                            is_fullscreen,
2294                        } => self.handle_fullscreen_effect(window_id, is_fullscreen),
2295
2296                        Effect::RefreshWindows => {
2297                            refreshing = true;
2298                        }
2299                        Effect::DispatchActionFrom {
2300                            window_id,
2301                            view_id,
2302                            action,
2303                        } => {
2304                            self.handle_dispatch_action_from_effect(
2305                                window_id,
2306                                Some(view_id),
2307                                action.as_ref(),
2308                            );
2309                        }
2310                        Effect::ActionDispatchNotification { action_id } => {
2311                            self.handle_action_dispatch_notification_effect(action_id)
2312                        }
2313                        Effect::WindowShouldCloseSubscription {
2314                            window_id,
2315                            callback,
2316                        } => {
2317                            self.handle_window_should_close_subscription_effect(window_id, callback)
2318                        }
2319                    }
2320                    self.pending_notifications.clear();
2321                    self.remove_dropped_entities();
2322                } else {
2323                    self.remove_dropped_entities();
2324                    if refreshing {
2325                        self.perform_window_refresh();
2326                    } else {
2327                        self.update_windows();
2328                    }
2329
2330                    if self.pending_effects.is_empty() {
2331                        for callback in after_window_update_callbacks.drain(..) {
2332                            callback(self);
2333                        }
2334
2335                        if self.pending_effects.is_empty() {
2336                            self.flushing_effects = false;
2337                            self.pending_notifications.clear();
2338                            self.pending_global_notifications.clear();
2339                            break;
2340                        }
2341                    }
2342
2343                    refreshing = false;
2344                }
2345            }
2346        }
2347    }
2348
2349    fn update_windows(&mut self) {
2350        let mut invalidations: HashMap<_, _> = Default::default();
2351        for (window_id, window) in &mut self.cx.windows {
2352            if let Some(invalidation) = window.invalidation.take() {
2353                invalidations.insert(*window_id, invalidation);
2354            }
2355        }
2356
2357        for (window_id, mut invalidation) in invalidations {
2358            if let Some((presenter, mut window)) =
2359                self.presenters_and_platform_windows.remove(&window_id)
2360            {
2361                {
2362                    let mut presenter = presenter.borrow_mut();
2363                    presenter.invalidate(&mut invalidation, self);
2364                    let scene =
2365                        presenter.build_scene(window.size(), window.scale_factor(), false, self);
2366                    window.present_scene(scene);
2367                }
2368                self.presenters_and_platform_windows
2369                    .insert(window_id, (presenter, window));
2370            }
2371        }
2372    }
2373
2374    fn window_was_resized(&mut self, window_id: usize) {
2375        self.pending_effects
2376            .push_back(Effect::ResizeWindow { window_id });
2377    }
2378
2379    fn window_was_fullscreen_changed(&mut self, window_id: usize, is_fullscreen: bool) {
2380        self.pending_effects.push_back(Effect::FullscreenWindow {
2381            window_id,
2382            is_fullscreen,
2383        });
2384    }
2385
2386    fn window_changed_active_status(&mut self, window_id: usize, is_active: bool) {
2387        self.pending_effects.push_back(Effect::ActivateWindow {
2388            window_id,
2389            is_active,
2390        });
2391    }
2392
2393    pub fn refresh_windows(&mut self) {
2394        self.pending_effects.push_back(Effect::RefreshWindows);
2395    }
2396
2397    pub fn dispatch_action_at(&mut self, window_id: usize, view_id: usize, action: impl Action) {
2398        self.dispatch_any_action_at(window_id, view_id, Box::new(action));
2399    }
2400
2401    pub fn dispatch_any_action_at(
2402        &mut self,
2403        window_id: usize,
2404        view_id: usize,
2405        action: Box<dyn Action>,
2406    ) {
2407        self.pending_effects.push_back(Effect::DispatchActionFrom {
2408            window_id,
2409            view_id,
2410            action,
2411        });
2412    }
2413
2414    fn perform_window_refresh(&mut self) {
2415        let mut presenters = mem::take(&mut self.presenters_and_platform_windows);
2416        for (window_id, (presenter, window)) in &mut presenters {
2417            let mut invalidation = self
2418                .cx
2419                .windows
2420                .get_mut(window_id)
2421                .unwrap()
2422                .invalidation
2423                .take();
2424            let mut presenter = presenter.borrow_mut();
2425            presenter.refresh(
2426                invalidation.as_mut().unwrap_or(&mut Default::default()),
2427                self,
2428            );
2429            let scene = presenter.build_scene(window.size(), window.scale_factor(), true, self);
2430            window.present_scene(scene);
2431        }
2432        self.presenters_and_platform_windows = presenters;
2433    }
2434
2435    fn emit_global_event(&mut self, payload: Box<dyn Any>) {
2436        let type_id = (&*payload).type_id();
2437
2438        let mut subscriptions = self.global_subscriptions.clone();
2439        subscriptions.emit_and_cleanup(type_id, self, |callback, this| {
2440            callback(payload.as_ref(), this);
2441            true //Always alive
2442        });
2443    }
2444
2445    fn handle_view_notification_effect(
2446        &mut self,
2447        observed_window_id: usize,
2448        observed_view_id: usize,
2449    ) {
2450        if self
2451            .cx
2452            .views
2453            .contains_key(&(observed_window_id, observed_view_id))
2454        {
2455            if let Some(window) = self.cx.windows.get_mut(&observed_window_id) {
2456                window
2457                    .invalidation
2458                    .get_or_insert_with(Default::default)
2459                    .updated
2460                    .insert(observed_view_id);
2461            }
2462
2463            let mut observations = self.observations.clone();
2464            observations.emit_and_cleanup(observed_view_id, self, |callback, this| callback(this));
2465        }
2466    }
2467
2468    fn handle_entity_release_effect(&mut self, entity_id: usize, entity: &dyn Any) {
2469        let callbacks = self.release_observations.lock().remove(&entity_id);
2470        if let Some(callbacks) = callbacks {
2471            for (_, callback) in callbacks {
2472                callback(entity, self);
2473            }
2474        }
2475    }
2476
2477    fn handle_fullscreen_effect(&mut self, window_id: usize, is_fullscreen: bool) {
2478        //Short circuit evaluation if we're already g2g
2479        if self
2480            .cx
2481            .windows
2482            .get(&window_id)
2483            .map(|w| w.is_fullscreen == is_fullscreen)
2484            .unwrap_or(false)
2485        {
2486            return;
2487        }
2488
2489        self.update(|this| {
2490            let window = this.cx.windows.get_mut(&window_id)?;
2491            window.is_fullscreen = is_fullscreen;
2492
2493            let mut observations = this.window_fullscreen_observations.clone();
2494            observations.emit_and_cleanup(window_id, this, |callback, this| {
2495                callback(is_fullscreen, this)
2496            });
2497
2498            Some(())
2499        });
2500    }
2501
2502    fn handle_window_activation_effect(&mut self, window_id: usize, active: bool) {
2503        //Short circuit evaluation if we're already g2g
2504        if self
2505            .cx
2506            .windows
2507            .get(&window_id)
2508            .map(|w| w.is_active == active)
2509            .unwrap_or(false)
2510        {
2511            return;
2512        }
2513
2514        self.update(|this| {
2515            let window = this.cx.windows.get_mut(&window_id)?;
2516            window.is_active = active;
2517
2518            //Handle focus
2519            let focused_id = window.focused_view_id?;
2520            for view_id in this.parents(window_id, focused_id).collect::<Vec<_>>() {
2521                if let Some(mut view) = this.cx.views.remove(&(window_id, view_id)) {
2522                    if active {
2523                        view.on_focus_in(this, window_id, view_id, focused_id);
2524                    } else {
2525                        view.on_focus_out(this, window_id, view_id, focused_id);
2526                    }
2527                    this.cx.views.insert((window_id, view_id), view);
2528                }
2529            }
2530
2531            let mut observations = this.window_activation_observations.clone();
2532            observations.emit_and_cleanup(window_id, this, |callback, this| callback(active, this));
2533
2534            Some(())
2535        });
2536    }
2537
2538    fn handle_focus_effect(&mut self, window_id: usize, focused_id: Option<usize>) {
2539        self.pending_focus_index.take();
2540
2541        if self
2542            .cx
2543            .windows
2544            .get(&window_id)
2545            .map(|w| w.focused_view_id)
2546            .map_or(false, |cur_focused| cur_focused == focused_id)
2547        {
2548            return;
2549        }
2550
2551        self.update(|this| {
2552            let blurred_id = this.cx.windows.get_mut(&window_id).and_then(|window| {
2553                let blurred_id = window.focused_view_id;
2554                window.focused_view_id = focused_id;
2555                blurred_id
2556            });
2557
2558            let blurred_parents = blurred_id
2559                .map(|blurred_id| this.parents(window_id, blurred_id).collect::<Vec<_>>())
2560                .unwrap_or_default();
2561            let focused_parents = focused_id
2562                .map(|focused_id| this.parents(window_id, focused_id).collect::<Vec<_>>())
2563                .unwrap_or_default();
2564
2565            if let Some(blurred_id) = blurred_id {
2566                for view_id in blurred_parents.iter().copied() {
2567                    if let Some(mut view) = this.cx.views.remove(&(window_id, view_id)) {
2568                        view.on_focus_out(this, window_id, view_id, blurred_id);
2569                        this.cx.views.insert((window_id, view_id), view);
2570                    }
2571                }
2572
2573                let mut subscriptions = this.focus_observations.clone();
2574                subscriptions
2575                    .emit_and_cleanup(blurred_id, this, |callback, this| callback(false, this));
2576            }
2577
2578            if let Some(focused_id) = focused_id {
2579                for view_id in focused_parents {
2580                    if let Some(mut view) = this.cx.views.remove(&(window_id, view_id)) {
2581                        view.on_focus_in(this, window_id, view_id, focused_id);
2582                        this.cx.views.insert((window_id, view_id), view);
2583                    }
2584                }
2585
2586                let mut subscriptions = this.focus_observations.clone();
2587                subscriptions
2588                    .emit_and_cleanup(focused_id, this, |callback, this| callback(true, this));
2589            }
2590        })
2591    }
2592
2593    fn handle_dispatch_action_from_effect(
2594        &mut self,
2595        window_id: usize,
2596        view_id: Option<usize>,
2597        action: &dyn Action,
2598    ) -> bool {
2599        self.update(|this| {
2600            if let Some(view_id) = view_id {
2601                this.halt_action_dispatch = false;
2602                this.visit_dispatch_path(window_id, view_id, |view_id, capture_phase, this| {
2603                    if let Some(mut view) = this.cx.views.remove(&(window_id, view_id)) {
2604                        let type_id = view.as_any().type_id();
2605
2606                        if let Some((name, mut handlers)) = this
2607                            .actions_mut(capture_phase)
2608                            .get_mut(&type_id)
2609                            .and_then(|h| h.remove_entry(&action.id()))
2610                        {
2611                            for handler in handlers.iter_mut().rev() {
2612                                this.halt_action_dispatch = true;
2613                                handler(view.as_mut(), action, this, window_id, view_id);
2614                                if this.halt_action_dispatch {
2615                                    break;
2616                                }
2617                            }
2618                            this.actions_mut(capture_phase)
2619                                .get_mut(&type_id)
2620                                .unwrap()
2621                                .insert(name, handlers);
2622                        }
2623
2624                        this.cx.views.insert((window_id, view_id), view);
2625                    }
2626
2627                    !this.halt_action_dispatch
2628                });
2629            }
2630
2631            if !this.halt_action_dispatch {
2632                this.halt_action_dispatch = this.dispatch_global_action_any(action);
2633            }
2634
2635            this.pending_effects
2636                .push_back(Effect::ActionDispatchNotification {
2637                    action_id: action.id(),
2638                });
2639            this.halt_action_dispatch
2640        })
2641    }
2642
2643    fn handle_action_dispatch_notification_effect(&mut self, action_id: TypeId) {
2644        let mut callbacks = mem::take(&mut *self.action_dispatch_observations.lock());
2645        for callback in callbacks.values_mut() {
2646            callback(action_id, self);
2647        }
2648        self.action_dispatch_observations.lock().extend(callbacks);
2649    }
2650
2651    fn handle_window_should_close_subscription_effect(
2652        &mut self,
2653        window_id: usize,
2654        mut callback: WindowShouldCloseSubscriptionCallback,
2655    ) {
2656        let mut app = self.upgrade();
2657        if let Some((_, window)) = self.presenters_and_platform_windows.get_mut(&window_id) {
2658            window.on_should_close(Box::new(move || app.update(|cx| callback(cx))))
2659        }
2660    }
2661
2662    pub fn focus(&mut self, window_id: usize, view_id: Option<usize>) {
2663        if let Some(pending_focus_index) = self.pending_focus_index {
2664            self.pending_effects.remove(pending_focus_index);
2665        }
2666        self.pending_focus_index = Some(self.pending_effects.len());
2667        self.pending_effects
2668            .push_back(Effect::Focus { window_id, view_id });
2669    }
2670
2671    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
2672    where
2673        F: FnOnce(AsyncAppContext) -> Fut,
2674        Fut: 'static + Future<Output = T>,
2675        T: 'static,
2676    {
2677        let future = f(self.to_async());
2678        let cx = self.to_async();
2679        self.foreground.spawn(async move {
2680            let result = future.await;
2681            cx.0.borrow_mut().flush_effects();
2682            result
2683        })
2684    }
2685
2686    pub fn to_async(&self) -> AsyncAppContext {
2687        AsyncAppContext(self.weak_self.as_ref().unwrap().upgrade().unwrap())
2688    }
2689
2690    pub fn write_to_clipboard(&self, item: ClipboardItem) {
2691        self.cx.platform.write_to_clipboard(item);
2692    }
2693
2694    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
2695        self.cx.platform.read_from_clipboard()
2696    }
2697
2698    #[cfg(any(test, feature = "test-support"))]
2699    pub fn leak_detector(&self) -> Arc<Mutex<LeakDetector>> {
2700        self.cx.ref_counts.lock().leak_detector.clone()
2701    }
2702}
2703
2704impl ReadModel for MutableAppContext {
2705    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
2706        if let Some(model) = self.cx.models.get(&handle.model_id) {
2707            model
2708                .as_any()
2709                .downcast_ref()
2710                .expect("downcast is type safe")
2711        } else {
2712            panic!("circular model reference");
2713        }
2714    }
2715}
2716
2717impl UpdateModel for MutableAppContext {
2718    fn update_model<T: Entity, V>(
2719        &mut self,
2720        handle: &ModelHandle<T>,
2721        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> V,
2722    ) -> V {
2723        if let Some(mut model) = self.cx.models.remove(&handle.model_id) {
2724            self.update(|this| {
2725                let mut cx = ModelContext::new(this, handle.model_id);
2726                let result = update(
2727                    model
2728                        .as_any_mut()
2729                        .downcast_mut()
2730                        .expect("downcast is type safe"),
2731                    &mut cx,
2732                );
2733                this.cx.models.insert(handle.model_id, model);
2734                result
2735            })
2736        } else {
2737            panic!("circular model update");
2738        }
2739    }
2740}
2741
2742impl UpgradeModelHandle for MutableAppContext {
2743    fn upgrade_model_handle<T: Entity>(
2744        &self,
2745        handle: &WeakModelHandle<T>,
2746    ) -> Option<ModelHandle<T>> {
2747        self.cx.upgrade_model_handle(handle)
2748    }
2749
2750    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
2751        self.cx.model_handle_is_upgradable(handle)
2752    }
2753
2754    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
2755        self.cx.upgrade_any_model_handle(handle)
2756    }
2757}
2758
2759impl UpgradeViewHandle for MutableAppContext {
2760    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
2761        self.cx.upgrade_view_handle(handle)
2762    }
2763
2764    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
2765        self.cx.upgrade_any_view_handle(handle)
2766    }
2767}
2768
2769impl ReadView for MutableAppContext {
2770    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
2771        if let Some(view) = self.cx.views.get(&(handle.window_id, handle.view_id)) {
2772            view.as_any().downcast_ref().expect("downcast is type safe")
2773        } else {
2774            panic!("circular view reference for type {}", type_name::<T>());
2775        }
2776    }
2777}
2778
2779impl UpdateView for MutableAppContext {
2780    fn update_view<T, S>(
2781        &mut self,
2782        handle: &ViewHandle<T>,
2783        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
2784    ) -> S
2785    where
2786        T: View,
2787    {
2788        self.update(|this| {
2789            let mut view = this
2790                .cx
2791                .views
2792                .remove(&(handle.window_id, handle.view_id))
2793                .expect("circular view update");
2794
2795            let mut cx = ViewContext::new(this, handle.window_id, handle.view_id);
2796            let result = update(
2797                view.as_any_mut()
2798                    .downcast_mut()
2799                    .expect("downcast is type safe"),
2800                &mut cx,
2801            );
2802            this.cx
2803                .views
2804                .insert((handle.window_id, handle.view_id), view);
2805            result
2806        })
2807    }
2808}
2809
2810impl AsRef<AppContext> for MutableAppContext {
2811    fn as_ref(&self) -> &AppContext {
2812        &self.cx
2813    }
2814}
2815
2816impl Deref for MutableAppContext {
2817    type Target = AppContext;
2818
2819    fn deref(&self) -> &Self::Target {
2820        &self.cx
2821    }
2822}
2823
2824#[derive(Debug)]
2825pub enum ParentId {
2826    View(usize),
2827    Root,
2828}
2829
2830pub struct AppContext {
2831    models: HashMap<usize, Box<dyn AnyModel>>,
2832    views: HashMap<(usize, usize), Box<dyn AnyView>>,
2833    pub(crate) parents: HashMap<(usize, usize), ParentId>,
2834    windows: HashMap<usize, Window>,
2835    globals: HashMap<TypeId, Box<dyn Any>>,
2836    element_states: HashMap<ElementStateId, Box<dyn Any>>,
2837    background: Arc<executor::Background>,
2838    ref_counts: Arc<Mutex<RefCounts>>,
2839    font_cache: Arc<FontCache>,
2840    platform: Arc<dyn Platform>,
2841}
2842
2843impl AppContext {
2844    pub(crate) fn root_view(&self, window_id: usize) -> Option<AnyViewHandle> {
2845        self.windows
2846            .get(&window_id)
2847            .map(|window| window.root_view.clone())
2848    }
2849
2850    pub fn root_view_id(&self, window_id: usize) -> Option<usize> {
2851        self.windows
2852            .get(&window_id)
2853            .map(|window| window.root_view.id())
2854    }
2855
2856    pub fn focused_view_id(&self, window_id: usize) -> Option<usize> {
2857        self.windows
2858            .get(&window_id)
2859            .and_then(|window| window.focused_view_id)
2860    }
2861
2862    pub fn background(&self) -> &Arc<executor::Background> {
2863        &self.background
2864    }
2865
2866    pub fn font_cache(&self) -> &Arc<FontCache> {
2867        &self.font_cache
2868    }
2869
2870    pub fn platform(&self) -> &Arc<dyn Platform> {
2871        &self.platform
2872    }
2873
2874    pub fn has_global<T: 'static>(&self) -> bool {
2875        self.globals.contains_key(&TypeId::of::<T>())
2876    }
2877
2878    pub fn global<T: 'static>(&self) -> &T {
2879        if let Some(global) = self.globals.get(&TypeId::of::<T>()) {
2880            global.downcast_ref().unwrap()
2881        } else {
2882            panic!("no global has been added for {}", type_name::<T>());
2883        }
2884    }
2885}
2886
2887impl ReadModel for AppContext {
2888    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
2889        if let Some(model) = self.models.get(&handle.model_id) {
2890            model
2891                .as_any()
2892                .downcast_ref()
2893                .expect("downcast should be type safe")
2894        } else {
2895            panic!("circular model reference");
2896        }
2897    }
2898}
2899
2900impl UpgradeModelHandle for AppContext {
2901    fn upgrade_model_handle<T: Entity>(
2902        &self,
2903        handle: &WeakModelHandle<T>,
2904    ) -> Option<ModelHandle<T>> {
2905        if self.models.contains_key(&handle.model_id) {
2906            Some(ModelHandle::new(handle.model_id, &self.ref_counts))
2907        } else {
2908            None
2909        }
2910    }
2911
2912    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
2913        self.models.contains_key(&handle.model_id)
2914    }
2915
2916    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
2917        if self.models.contains_key(&handle.model_id) {
2918            Some(AnyModelHandle::new(
2919                handle.model_id,
2920                handle.model_type,
2921                self.ref_counts.clone(),
2922            ))
2923        } else {
2924            None
2925        }
2926    }
2927}
2928
2929impl UpgradeViewHandle for AppContext {
2930    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
2931        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
2932            Some(ViewHandle::new(
2933                handle.window_id,
2934                handle.view_id,
2935                &self.ref_counts,
2936            ))
2937        } else {
2938            None
2939        }
2940    }
2941
2942    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
2943        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
2944            Some(AnyViewHandle::new(
2945                handle.window_id,
2946                handle.view_id,
2947                handle.view_type,
2948                self.ref_counts.clone(),
2949            ))
2950        } else {
2951            None
2952        }
2953    }
2954}
2955
2956impl ReadView for AppContext {
2957    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
2958        if let Some(view) = self.views.get(&(handle.window_id, handle.view_id)) {
2959            view.as_any()
2960                .downcast_ref()
2961                .expect("downcast should be type safe")
2962        } else {
2963            panic!("circular view reference");
2964        }
2965    }
2966}
2967
2968struct Window {
2969    root_view: AnyViewHandle,
2970    focused_view_id: Option<usize>,
2971    is_active: bool,
2972    is_fullscreen: bool,
2973    invalidation: Option<WindowInvalidation>,
2974}
2975
2976#[derive(Default, Clone)]
2977pub struct WindowInvalidation {
2978    pub updated: HashSet<usize>,
2979    pub removed: Vec<usize>,
2980}
2981
2982pub enum Effect {
2983    Subscription {
2984        entity_id: usize,
2985        subscription_id: usize,
2986        callback: SubscriptionCallback,
2987    },
2988    Event {
2989        entity_id: usize,
2990        payload: Box<dyn Any>,
2991    },
2992    GlobalSubscription {
2993        type_id: TypeId,
2994        subscription_id: usize,
2995        callback: GlobalSubscriptionCallback,
2996    },
2997    GlobalEvent {
2998        payload: Box<dyn Any>,
2999    },
3000    Observation {
3001        entity_id: usize,
3002        subscription_id: usize,
3003        callback: ObservationCallback,
3004    },
3005    ModelNotification {
3006        model_id: usize,
3007    },
3008    ViewNotification {
3009        window_id: usize,
3010        view_id: usize,
3011    },
3012    Deferred {
3013        callback: Box<dyn FnOnce(&mut MutableAppContext)>,
3014        after_window_update: bool,
3015    },
3016    GlobalNotification {
3017        type_id: TypeId,
3018    },
3019    ModelRelease {
3020        model_id: usize,
3021        model: Box<dyn AnyModel>,
3022    },
3023    ViewRelease {
3024        view_id: usize,
3025        view: Box<dyn AnyView>,
3026    },
3027    Focus {
3028        window_id: usize,
3029        view_id: Option<usize>,
3030    },
3031    FocusObservation {
3032        view_id: usize,
3033        subscription_id: usize,
3034        callback: FocusObservationCallback,
3035    },
3036    ResizeWindow {
3037        window_id: usize,
3038    },
3039    FullscreenWindow {
3040        window_id: usize,
3041        is_fullscreen: bool,
3042    },
3043    ActivateWindow {
3044        window_id: usize,
3045        is_active: bool,
3046    },
3047    WindowActivationObservation {
3048        window_id: usize,
3049        subscription_id: usize,
3050        callback: WindowActivationCallback,
3051    },
3052    WindowFullscreenObservation {
3053        window_id: usize,
3054        subscription_id: usize,
3055        callback: WindowFullscreenCallback,
3056    },
3057    RefreshWindows,
3058    DispatchActionFrom {
3059        window_id: usize,
3060        view_id: usize,
3061        action: Box<dyn Action>,
3062    },
3063    ActionDispatchNotification {
3064        action_id: TypeId,
3065    },
3066    WindowShouldCloseSubscription {
3067        window_id: usize,
3068        callback: WindowShouldCloseSubscriptionCallback,
3069    },
3070}
3071
3072impl Debug for Effect {
3073    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3074        match self {
3075            Effect::Subscription {
3076                entity_id,
3077                subscription_id,
3078                ..
3079            } => f
3080                .debug_struct("Effect::Subscribe")
3081                .field("entity_id", entity_id)
3082                .field("subscription_id", subscription_id)
3083                .finish(),
3084            Effect::Event { entity_id, .. } => f
3085                .debug_struct("Effect::Event")
3086                .field("entity_id", entity_id)
3087                .finish(),
3088            Effect::GlobalSubscription {
3089                type_id,
3090                subscription_id,
3091                ..
3092            } => f
3093                .debug_struct("Effect::Subscribe")
3094                .field("type_id", type_id)
3095                .field("subscription_id", subscription_id)
3096                .finish(),
3097            Effect::GlobalEvent { payload, .. } => f
3098                .debug_struct("Effect::GlobalEvent")
3099                .field("type_id", &(&*payload).type_id())
3100                .finish(),
3101            Effect::Observation {
3102                entity_id,
3103                subscription_id,
3104                ..
3105            } => f
3106                .debug_struct("Effect::Observation")
3107                .field("entity_id", entity_id)
3108                .field("subscription_id", subscription_id)
3109                .finish(),
3110            Effect::ModelNotification { model_id } => f
3111                .debug_struct("Effect::ModelNotification")
3112                .field("model_id", model_id)
3113                .finish(),
3114            Effect::ViewNotification { window_id, view_id } => f
3115                .debug_struct("Effect::ViewNotification")
3116                .field("window_id", window_id)
3117                .field("view_id", view_id)
3118                .finish(),
3119            Effect::GlobalNotification { type_id } => f
3120                .debug_struct("Effect::GlobalNotification")
3121                .field("type_id", type_id)
3122                .finish(),
3123            Effect::Deferred { .. } => f.debug_struct("Effect::Deferred").finish(),
3124            Effect::ModelRelease { model_id, .. } => f
3125                .debug_struct("Effect::ModelRelease")
3126                .field("model_id", model_id)
3127                .finish(),
3128            Effect::ViewRelease { view_id, .. } => f
3129                .debug_struct("Effect::ViewRelease")
3130                .field("view_id", view_id)
3131                .finish(),
3132            Effect::Focus { window_id, view_id } => f
3133                .debug_struct("Effect::Focus")
3134                .field("window_id", window_id)
3135                .field("view_id", view_id)
3136                .finish(),
3137            Effect::FocusObservation {
3138                view_id,
3139                subscription_id,
3140                ..
3141            } => f
3142                .debug_struct("Effect::FocusObservation")
3143                .field("view_id", view_id)
3144                .field("subscription_id", subscription_id)
3145                .finish(),
3146            Effect::DispatchActionFrom {
3147                window_id, view_id, ..
3148            } => f
3149                .debug_struct("Effect::DispatchActionFrom")
3150                .field("window_id", window_id)
3151                .field("view_id", view_id)
3152                .finish(),
3153            Effect::ActionDispatchNotification { action_id, .. } => f
3154                .debug_struct("Effect::ActionDispatchNotification")
3155                .field("action_id", action_id)
3156                .finish(),
3157            Effect::ResizeWindow { window_id } => f
3158                .debug_struct("Effect::RefreshWindow")
3159                .field("window_id", window_id)
3160                .finish(),
3161            Effect::WindowActivationObservation {
3162                window_id,
3163                subscription_id,
3164                ..
3165            } => f
3166                .debug_struct("Effect::WindowActivationObservation")
3167                .field("window_id", window_id)
3168                .field("subscription_id", subscription_id)
3169                .finish(),
3170            Effect::ActivateWindow {
3171                window_id,
3172                is_active,
3173            } => f
3174                .debug_struct("Effect::ActivateWindow")
3175                .field("window_id", window_id)
3176                .field("is_active", is_active)
3177                .finish(),
3178            Effect::FullscreenWindow {
3179                window_id,
3180                is_fullscreen,
3181            } => f
3182                .debug_struct("Effect::FullscreenWindow")
3183                .field("window_id", window_id)
3184                .field("is_fullscreen", is_fullscreen)
3185                .finish(),
3186            Effect::WindowFullscreenObservation {
3187                window_id,
3188                subscription_id,
3189                callback: _,
3190            } => f
3191                .debug_struct("Effect::WindowFullscreenObservation")
3192                .field("window_id", window_id)
3193                .field("subscription_id", subscription_id)
3194                .finish(),
3195            Effect::RefreshWindows => f.debug_struct("Effect::FullViewRefresh").finish(),
3196            Effect::WindowShouldCloseSubscription { window_id, .. } => f
3197                .debug_struct("Effect::WindowShouldCloseSubscription")
3198                .field("window_id", window_id)
3199                .finish(),
3200        }
3201    }
3202}
3203
3204pub trait AnyModel {
3205    fn as_any(&self) -> &dyn Any;
3206    fn as_any_mut(&mut self) -> &mut dyn Any;
3207    fn release(&mut self, cx: &mut MutableAppContext);
3208    fn app_will_quit(
3209        &mut self,
3210        cx: &mut MutableAppContext,
3211    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
3212}
3213
3214impl<T> AnyModel for T
3215where
3216    T: Entity,
3217{
3218    fn as_any(&self) -> &dyn Any {
3219        self
3220    }
3221
3222    fn as_any_mut(&mut self) -> &mut dyn Any {
3223        self
3224    }
3225
3226    fn release(&mut self, cx: &mut MutableAppContext) {
3227        self.release(cx);
3228    }
3229
3230    fn app_will_quit(
3231        &mut self,
3232        cx: &mut MutableAppContext,
3233    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
3234        self.app_will_quit(cx)
3235    }
3236}
3237
3238pub trait AnyView {
3239    fn as_any(&self) -> &dyn Any;
3240    fn as_any_mut(&mut self) -> &mut dyn Any;
3241    fn release(&mut self, cx: &mut MutableAppContext);
3242    fn app_will_quit(
3243        &mut self,
3244        cx: &mut MutableAppContext,
3245    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
3246    fn ui_name(&self) -> &'static str;
3247    fn render(&mut self, params: RenderParams, cx: &mut MutableAppContext) -> ElementBox;
3248    fn on_focus_in(
3249        &mut self,
3250        cx: &mut MutableAppContext,
3251        window_id: usize,
3252        view_id: usize,
3253        focused_id: usize,
3254    );
3255    fn on_focus_out(
3256        &mut self,
3257        cx: &mut MutableAppContext,
3258        window_id: usize,
3259        view_id: usize,
3260        focused_id: usize,
3261    );
3262    fn keymap_context(&self, cx: &AppContext) -> keymap::Context;
3263    fn debug_json(&self, cx: &AppContext) -> serde_json::Value;
3264
3265    fn text_for_range(&self, range: Range<usize>, cx: &AppContext) -> Option<String>;
3266    fn selected_text_range(&self, cx: &AppContext) -> Option<Range<usize>>;
3267    fn marked_text_range(&self, cx: &AppContext) -> Option<Range<usize>>;
3268    fn unmark_text(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize);
3269    fn replace_text_in_range(
3270        &mut self,
3271        range: Option<Range<usize>>,
3272        text: &str,
3273        cx: &mut MutableAppContext,
3274        window_id: usize,
3275        view_id: usize,
3276    );
3277    fn replace_and_mark_text_in_range(
3278        &mut self,
3279        range: Option<Range<usize>>,
3280        new_text: &str,
3281        new_selected_range: Option<Range<usize>>,
3282        cx: &mut MutableAppContext,
3283        window_id: usize,
3284        view_id: usize,
3285    );
3286    fn any_handle(&self, window_id: usize, view_id: usize, cx: &AppContext) -> AnyViewHandle {
3287        AnyViewHandle::new(
3288            window_id,
3289            view_id,
3290            self.as_any().type_id(),
3291            cx.ref_counts.clone(),
3292        )
3293    }
3294}
3295
3296impl<T> AnyView for T
3297where
3298    T: View,
3299{
3300    fn as_any(&self) -> &dyn Any {
3301        self
3302    }
3303
3304    fn as_any_mut(&mut self) -> &mut dyn Any {
3305        self
3306    }
3307
3308    fn release(&mut self, cx: &mut MutableAppContext) {
3309        self.release(cx);
3310    }
3311
3312    fn app_will_quit(
3313        &mut self,
3314        cx: &mut MutableAppContext,
3315    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
3316        self.app_will_quit(cx)
3317    }
3318
3319    fn ui_name(&self) -> &'static str {
3320        T::ui_name()
3321    }
3322
3323    fn render(&mut self, params: RenderParams, cx: &mut MutableAppContext) -> ElementBox {
3324        View::render(self, &mut RenderContext::new(params, cx))
3325    }
3326
3327    fn on_focus_in(
3328        &mut self,
3329        cx: &mut MutableAppContext,
3330        window_id: usize,
3331        view_id: usize,
3332        focused_id: usize,
3333    ) {
3334        let mut cx = ViewContext::new(cx, window_id, view_id);
3335        let focused_view_handle: AnyViewHandle = if view_id == focused_id {
3336            cx.handle().into()
3337        } else {
3338            let focused_type = cx
3339                .views
3340                .get(&(window_id, focused_id))
3341                .unwrap()
3342                .as_any()
3343                .type_id();
3344            AnyViewHandle::new(window_id, focused_id, focused_type, cx.ref_counts.clone())
3345        };
3346        View::on_focus_in(self, focused_view_handle, &mut cx);
3347    }
3348
3349    fn on_focus_out(
3350        &mut self,
3351        cx: &mut MutableAppContext,
3352        window_id: usize,
3353        view_id: usize,
3354        blurred_id: usize,
3355    ) {
3356        let mut cx = ViewContext::new(cx, window_id, view_id);
3357        let blurred_view_handle: AnyViewHandle = if view_id == blurred_id {
3358            cx.handle().into()
3359        } else {
3360            let blurred_type = cx
3361                .views
3362                .get(&(window_id, blurred_id))
3363                .unwrap()
3364                .as_any()
3365                .type_id();
3366            AnyViewHandle::new(window_id, blurred_id, blurred_type, cx.ref_counts.clone())
3367        };
3368        View::on_focus_out(self, blurred_view_handle, &mut cx);
3369    }
3370
3371    fn keymap_context(&self, cx: &AppContext) -> keymap::Context {
3372        View::keymap_context(self, cx)
3373    }
3374
3375    fn debug_json(&self, cx: &AppContext) -> serde_json::Value {
3376        View::debug_json(self, cx)
3377    }
3378
3379    fn text_for_range(&self, range: Range<usize>, cx: &AppContext) -> Option<String> {
3380        View::text_for_range(self, range, cx)
3381    }
3382
3383    fn selected_text_range(&self, cx: &AppContext) -> Option<Range<usize>> {
3384        View::selected_text_range(self, cx)
3385    }
3386
3387    fn marked_text_range(&self, cx: &AppContext) -> Option<Range<usize>> {
3388        View::marked_text_range(self, cx)
3389    }
3390
3391    fn unmark_text(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize) {
3392        let mut cx = ViewContext::new(cx, window_id, view_id);
3393        View::unmark_text(self, &mut cx)
3394    }
3395
3396    fn replace_text_in_range(
3397        &mut self,
3398        range: Option<Range<usize>>,
3399        text: &str,
3400        cx: &mut MutableAppContext,
3401        window_id: usize,
3402        view_id: usize,
3403    ) {
3404        let mut cx = ViewContext::new(cx, window_id, view_id);
3405        View::replace_text_in_range(self, range, text, &mut cx)
3406    }
3407
3408    fn replace_and_mark_text_in_range(
3409        &mut self,
3410        range: Option<Range<usize>>,
3411        new_text: &str,
3412        new_selected_range: Option<Range<usize>>,
3413        cx: &mut MutableAppContext,
3414        window_id: usize,
3415        view_id: usize,
3416    ) {
3417        let mut cx = ViewContext::new(cx, window_id, view_id);
3418        View::replace_and_mark_text_in_range(self, range, new_text, new_selected_range, &mut cx)
3419    }
3420}
3421
3422pub struct ModelContext<'a, T: ?Sized> {
3423    app: &'a mut MutableAppContext,
3424    model_id: usize,
3425    model_type: PhantomData<T>,
3426    halt_stream: bool,
3427}
3428
3429impl<'a, T: Entity> ModelContext<'a, T> {
3430    fn new(app: &'a mut MutableAppContext, model_id: usize) -> Self {
3431        Self {
3432            app,
3433            model_id,
3434            model_type: PhantomData,
3435            halt_stream: false,
3436        }
3437    }
3438
3439    pub fn background(&self) -> &Arc<executor::Background> {
3440        &self.app.cx.background
3441    }
3442
3443    pub fn halt_stream(&mut self) {
3444        self.halt_stream = true;
3445    }
3446
3447    pub fn model_id(&self) -> usize {
3448        self.model_id
3449    }
3450
3451    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
3452    where
3453        S: Entity,
3454        F: FnOnce(&mut ModelContext<S>) -> S,
3455    {
3456        self.app.add_model(build_model)
3457    }
3458
3459    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut T, &mut ModelContext<T>)) {
3460        let handle = self.handle();
3461        self.app.defer(move |cx| {
3462            handle.update(cx, |model, cx| {
3463                callback(model, cx);
3464            })
3465        })
3466    }
3467
3468    pub fn emit(&mut self, payload: T::Event) {
3469        self.app.pending_effects.push_back(Effect::Event {
3470            entity_id: self.model_id,
3471            payload: Box::new(payload),
3472        });
3473    }
3474
3475    pub fn notify(&mut self) {
3476        self.app.notify_model(self.model_id);
3477    }
3478
3479    pub fn subscribe<S: Entity, F>(
3480        &mut self,
3481        handle: &ModelHandle<S>,
3482        mut callback: F,
3483    ) -> Subscription
3484    where
3485        S::Event: 'static,
3486        F: 'static + FnMut(&mut T, ModelHandle<S>, &S::Event, &mut ModelContext<T>),
3487    {
3488        let subscriber = self.weak_handle();
3489        self.app
3490            .subscribe_internal(handle, move |emitter, event, cx| {
3491                if let Some(subscriber) = subscriber.upgrade(cx) {
3492                    subscriber.update(cx, |subscriber, cx| {
3493                        callback(subscriber, emitter, event, cx);
3494                    });
3495                    true
3496                } else {
3497                    false
3498                }
3499            })
3500    }
3501
3502    pub fn observe<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F) -> Subscription
3503    where
3504        S: Entity,
3505        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ModelContext<T>),
3506    {
3507        let observer = self.weak_handle();
3508        self.app.observe_internal(handle, move |observed, cx| {
3509            if let Some(observer) = observer.upgrade(cx) {
3510                observer.update(cx, |observer, cx| {
3511                    callback(observer, observed, cx);
3512                });
3513                true
3514            } else {
3515                false
3516            }
3517        })
3518    }
3519
3520    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
3521    where
3522        G: Any,
3523        F: 'static + FnMut(&mut T, &mut ModelContext<T>),
3524    {
3525        let observer = self.weak_handle();
3526        self.app.observe_global::<G, _>(move |cx| {
3527            if let Some(observer) = observer.upgrade(cx) {
3528                observer.update(cx, |observer, cx| callback(observer, cx));
3529            }
3530        })
3531    }
3532
3533    pub fn observe_release<S, F>(
3534        &mut self,
3535        handle: &ModelHandle<S>,
3536        mut callback: F,
3537    ) -> Subscription
3538    where
3539        S: Entity,
3540        F: 'static + FnMut(&mut T, &S, &mut ModelContext<T>),
3541    {
3542        let observer = self.weak_handle();
3543        self.app.observe_release(handle, move |released, cx| {
3544            if let Some(observer) = observer.upgrade(cx) {
3545                observer.update(cx, |observer, cx| {
3546                    callback(observer, released, cx);
3547                });
3548            }
3549        })
3550    }
3551
3552    pub fn handle(&self) -> ModelHandle<T> {
3553        ModelHandle::new(self.model_id, &self.app.cx.ref_counts)
3554    }
3555
3556    pub fn weak_handle(&self) -> WeakModelHandle<T> {
3557        WeakModelHandle::new(self.model_id)
3558    }
3559
3560    pub fn spawn<F, Fut, S>(&self, f: F) -> Task<S>
3561    where
3562        F: FnOnce(ModelHandle<T>, AsyncAppContext) -> Fut,
3563        Fut: 'static + Future<Output = S>,
3564        S: 'static,
3565    {
3566        let handle = self.handle();
3567        self.app.spawn(|cx| f(handle, cx))
3568    }
3569
3570    pub fn spawn_weak<F, Fut, S>(&self, f: F) -> Task<S>
3571    where
3572        F: FnOnce(WeakModelHandle<T>, AsyncAppContext) -> Fut,
3573        Fut: 'static + Future<Output = S>,
3574        S: 'static,
3575    {
3576        let handle = self.weak_handle();
3577        self.app.spawn(|cx| f(handle, cx))
3578    }
3579}
3580
3581impl<M> AsRef<AppContext> for ModelContext<'_, M> {
3582    fn as_ref(&self) -> &AppContext {
3583        &self.app.cx
3584    }
3585}
3586
3587impl<M> AsMut<MutableAppContext> for ModelContext<'_, M> {
3588    fn as_mut(&mut self) -> &mut MutableAppContext {
3589        self.app
3590    }
3591}
3592
3593impl<M> ReadModel for ModelContext<'_, M> {
3594    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
3595        self.app.read_model(handle)
3596    }
3597}
3598
3599impl<M> UpdateModel for ModelContext<'_, M> {
3600    fn update_model<T: Entity, V>(
3601        &mut self,
3602        handle: &ModelHandle<T>,
3603        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> V,
3604    ) -> V {
3605        self.app.update_model(handle, update)
3606    }
3607}
3608
3609impl<M> UpgradeModelHandle for ModelContext<'_, M> {
3610    fn upgrade_model_handle<T: Entity>(
3611        &self,
3612        handle: &WeakModelHandle<T>,
3613    ) -> Option<ModelHandle<T>> {
3614        self.cx.upgrade_model_handle(handle)
3615    }
3616
3617    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
3618        self.cx.model_handle_is_upgradable(handle)
3619    }
3620
3621    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
3622        self.cx.upgrade_any_model_handle(handle)
3623    }
3624}
3625
3626impl<M> Deref for ModelContext<'_, M> {
3627    type Target = MutableAppContext;
3628
3629    fn deref(&self) -> &Self::Target {
3630        self.app
3631    }
3632}
3633
3634impl<M> DerefMut for ModelContext<'_, M> {
3635    fn deref_mut(&mut self) -> &mut Self::Target {
3636        &mut self.app
3637    }
3638}
3639
3640pub struct ViewContext<'a, T: ?Sized> {
3641    app: &'a mut MutableAppContext,
3642    window_id: usize,
3643    view_id: usize,
3644    view_type: PhantomData<T>,
3645}
3646
3647impl<'a, T: View> ViewContext<'a, T> {
3648    fn new(app: &'a mut MutableAppContext, window_id: usize, view_id: usize) -> Self {
3649        Self {
3650            app,
3651            window_id,
3652            view_id,
3653            view_type: PhantomData,
3654        }
3655    }
3656
3657    pub fn handle(&self) -> ViewHandle<T> {
3658        ViewHandle::new(self.window_id, self.view_id, &self.app.cx.ref_counts)
3659    }
3660
3661    pub fn weak_handle(&self) -> WeakViewHandle<T> {
3662        WeakViewHandle::new(self.window_id, self.view_id)
3663    }
3664
3665    pub fn window_id(&self) -> usize {
3666        self.window_id
3667    }
3668
3669    pub fn view_id(&self) -> usize {
3670        self.view_id
3671    }
3672
3673    pub fn foreground(&self) -> &Rc<executor::Foreground> {
3674        self.app.foreground()
3675    }
3676
3677    pub fn background_executor(&self) -> &Arc<executor::Background> {
3678        &self.app.cx.background
3679    }
3680
3681    pub fn platform(&self) -> Arc<dyn Platform> {
3682        self.app.platform()
3683    }
3684
3685    pub fn show_character_palette(&self) {
3686        self.app.show_character_palette(self.window_id);
3687    }
3688
3689    pub fn minimize_window(&self) {
3690        self.app.minimize_window(self.window_id)
3691    }
3692
3693    pub fn zoom_window(&self) {
3694        self.app.zoom_window(self.window_id)
3695    }
3696
3697    pub fn toggle_full_screen(&self) {
3698        self.app.toggle_window_full_screen(self.window_id)
3699    }
3700
3701    pub fn prompt(
3702        &self,
3703        level: PromptLevel,
3704        msg: &str,
3705        answers: &[&str],
3706    ) -> oneshot::Receiver<usize> {
3707        self.app.prompt(self.window_id, level, msg, answers)
3708    }
3709
3710    pub fn prompt_for_paths(
3711        &self,
3712        options: PathPromptOptions,
3713    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
3714        self.app.prompt_for_paths(options)
3715    }
3716
3717    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
3718        self.app.prompt_for_new_path(directory)
3719    }
3720
3721    pub fn debug_elements(&self) -> crate::json::Value {
3722        self.app.debug_elements(self.window_id).unwrap()
3723    }
3724
3725    pub fn focus<S>(&mut self, handle: S)
3726    where
3727        S: Into<AnyViewHandle>,
3728    {
3729        let handle = handle.into();
3730        self.app.focus(handle.window_id, Some(handle.view_id));
3731    }
3732
3733    pub fn focus_self(&mut self) {
3734        self.app.focus(self.window_id, Some(self.view_id));
3735    }
3736
3737    pub fn is_self_focused(&self) -> bool {
3738        self.app.focused_view_id(self.window_id) == Some(self.view_id)
3739    }
3740
3741    pub fn blur(&mut self) {
3742        self.app.focus(self.window_id, None);
3743    }
3744
3745    pub fn set_window_title(&mut self, title: &str) {
3746        let window_id = self.window_id();
3747        if let Some((_, window)) = self.presenters_and_platform_windows.get_mut(&window_id) {
3748            window.set_title(title);
3749        }
3750    }
3751
3752    pub fn set_window_edited(&mut self, edited: bool) {
3753        let window_id = self.window_id();
3754        if let Some((_, window)) = self.presenters_and_platform_windows.get_mut(&window_id) {
3755            window.set_edited(edited);
3756        }
3757    }
3758
3759    pub fn on_window_should_close<F>(&mut self, mut callback: F)
3760    where
3761        F: 'static + FnMut(&mut T, &mut ViewContext<T>) -> bool,
3762    {
3763        let window_id = self.window_id();
3764        let view = self.weak_handle();
3765        self.pending_effects
3766            .push_back(Effect::WindowShouldCloseSubscription {
3767                window_id,
3768                callback: Box::new(move |cx| {
3769                    if let Some(view) = view.upgrade(cx) {
3770                        view.update(cx, |view, cx| callback(view, cx))
3771                    } else {
3772                        true
3773                    }
3774                }),
3775            });
3776    }
3777
3778    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
3779    where
3780        S: Entity,
3781        F: FnOnce(&mut ModelContext<S>) -> S,
3782    {
3783        self.app.add_model(build_model)
3784    }
3785
3786    pub fn add_view<S, F>(&mut self, build_view: F) -> ViewHandle<S>
3787    where
3788        S: View,
3789        F: FnOnce(&mut ViewContext<S>) -> S,
3790    {
3791        self.app
3792            .build_and_insert_view(self.window_id, ParentId::View(self.view_id), |cx| {
3793                Some(build_view(cx))
3794            })
3795            .unwrap()
3796    }
3797
3798    pub fn add_option_view<S, F>(&mut self, build_view: F) -> Option<ViewHandle<S>>
3799    where
3800        S: View,
3801        F: FnOnce(&mut ViewContext<S>) -> Option<S>,
3802    {
3803        self.app
3804            .build_and_insert_view(self.window_id, ParentId::View(self.view_id), build_view)
3805    }
3806
3807    pub fn reparent(&mut self, view_handle: impl Into<AnyViewHandle>) {
3808        let view_handle = view_handle.into();
3809        if self.window_id != view_handle.window_id {
3810            panic!("Can't reparent view to a view from a different window");
3811        }
3812        self.cx
3813            .parents
3814            .remove(&(view_handle.window_id, view_handle.view_id));
3815        let new_parent_id = self.view_id;
3816        self.cx.parents.insert(
3817            (view_handle.window_id, view_handle.view_id),
3818            ParentId::View(new_parent_id),
3819        );
3820    }
3821
3822    pub fn replace_root_view<V, F>(&mut self, build_root_view: F) -> ViewHandle<V>
3823    where
3824        V: View,
3825        F: FnOnce(&mut ViewContext<V>) -> V,
3826    {
3827        let window_id = self.window_id;
3828        self.update(|this| {
3829            let root_view = this
3830                .build_and_insert_view(window_id, ParentId::Root, |cx| Some(build_root_view(cx)))
3831                .unwrap();
3832            let window = this.cx.windows.get_mut(&window_id).unwrap();
3833            window.root_view = root_view.clone().into();
3834            window.focused_view_id = Some(root_view.id());
3835            root_view
3836        })
3837    }
3838
3839    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
3840    where
3841        E: Entity,
3842        E::Event: 'static,
3843        H: Handle<E>,
3844        F: 'static + FnMut(&mut T, H, &E::Event, &mut ViewContext<T>),
3845    {
3846        let subscriber = self.weak_handle();
3847        self.app
3848            .subscribe_internal(handle, move |emitter, event, cx| {
3849                if let Some(subscriber) = subscriber.upgrade(cx) {
3850                    subscriber.update(cx, |subscriber, cx| {
3851                        callback(subscriber, emitter, event, cx);
3852                    });
3853                    true
3854                } else {
3855                    false
3856                }
3857            })
3858    }
3859
3860    pub fn observe<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
3861    where
3862        E: Entity,
3863        H: Handle<E>,
3864        F: 'static + FnMut(&mut T, H, &mut ViewContext<T>),
3865    {
3866        let observer = self.weak_handle();
3867        self.app.observe_internal(handle, move |observed, cx| {
3868            if let Some(observer) = observer.upgrade(cx) {
3869                observer.update(cx, |observer, cx| {
3870                    callback(observer, observed, cx);
3871                });
3872                true
3873            } else {
3874                false
3875            }
3876        })
3877    }
3878
3879    pub fn observe_focus<F, V>(&mut self, handle: &ViewHandle<V>, mut callback: F) -> Subscription
3880    where
3881        F: 'static + FnMut(&mut T, ViewHandle<V>, bool, &mut ViewContext<T>),
3882        V: View,
3883    {
3884        let observer = self.weak_handle();
3885        self.app
3886            .observe_focus(handle, move |observed, focused, cx| {
3887                if let Some(observer) = observer.upgrade(cx) {
3888                    observer.update(cx, |observer, cx| {
3889                        callback(observer, observed, focused, cx);
3890                    });
3891                    true
3892                } else {
3893                    false
3894                }
3895            })
3896    }
3897
3898    pub fn observe_release<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
3899    where
3900        E: Entity,
3901        H: Handle<E>,
3902        F: 'static + FnMut(&mut T, &E, &mut ViewContext<T>),
3903    {
3904        let observer = self.weak_handle();
3905        self.app.observe_release(handle, move |released, cx| {
3906            if let Some(observer) = observer.upgrade(cx) {
3907                observer.update(cx, |observer, cx| {
3908                    callback(observer, released, cx);
3909                });
3910            }
3911        })
3912    }
3913
3914    pub fn observe_actions<F>(&mut self, mut callback: F) -> Subscription
3915    where
3916        F: 'static + FnMut(&mut T, TypeId, &mut ViewContext<T>),
3917    {
3918        let observer = self.weak_handle();
3919        self.app.observe_actions(move |action_id, cx| {
3920            if let Some(observer) = observer.upgrade(cx) {
3921                observer.update(cx, |observer, cx| {
3922                    callback(observer, action_id, cx);
3923                });
3924            }
3925        })
3926    }
3927
3928    pub fn observe_window_activation<F>(&mut self, mut callback: F) -> Subscription
3929    where
3930        F: 'static + FnMut(&mut T, bool, &mut ViewContext<T>),
3931    {
3932        let observer = self.weak_handle();
3933        self.app
3934            .observe_window_activation(self.window_id(), move |active, cx| {
3935                if let Some(observer) = observer.upgrade(cx) {
3936                    observer.update(cx, |observer, cx| {
3937                        callback(observer, active, cx);
3938                    });
3939                    true
3940                } else {
3941                    false
3942                }
3943            })
3944    }
3945
3946    pub fn observe_fullscreen<F>(&mut self, mut callback: F) -> Subscription
3947    where
3948        F: 'static + FnMut(&mut T, bool, &mut ViewContext<T>),
3949    {
3950        let observer = self.weak_handle();
3951        self.app
3952            .observe_fullscreen(self.window_id(), move |active, cx| {
3953                if let Some(observer) = observer.upgrade(cx) {
3954                    observer.update(cx, |observer, cx| {
3955                        callback(observer, active, cx);
3956                    });
3957                    true
3958                } else {
3959                    false
3960                }
3961            })
3962    }
3963
3964    pub fn emit(&mut self, payload: T::Event) {
3965        self.app.pending_effects.push_back(Effect::Event {
3966            entity_id: self.view_id,
3967            payload: Box::new(payload),
3968        });
3969    }
3970
3971    pub fn notify(&mut self) {
3972        self.app.notify_view(self.window_id, self.view_id);
3973    }
3974
3975    pub fn dispatch_any_action(&mut self, action: Box<dyn Action>) {
3976        self.app
3977            .dispatch_any_action_at(self.window_id, self.view_id, action)
3978    }
3979
3980    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut T, &mut ViewContext<T>)) {
3981        let handle = self.handle();
3982        self.app.defer(move |cx| {
3983            handle.update(cx, |view, cx| {
3984                callback(view, cx);
3985            })
3986        })
3987    }
3988
3989    pub fn after_window_update(
3990        &mut self,
3991        callback: impl 'static + FnOnce(&mut T, &mut ViewContext<T>),
3992    ) {
3993        let handle = self.handle();
3994        self.app.after_window_update(move |cx| {
3995            handle.update(cx, |view, cx| {
3996                callback(view, cx);
3997            })
3998        })
3999    }
4000
4001    pub fn propagate_action(&mut self) {
4002        self.app.halt_action_dispatch = false;
4003    }
4004
4005    pub fn spawn<F, Fut, S>(&self, f: F) -> Task<S>
4006    where
4007        F: FnOnce(ViewHandle<T>, AsyncAppContext) -> Fut,
4008        Fut: 'static + Future<Output = S>,
4009        S: 'static,
4010    {
4011        let handle = self.handle();
4012        self.app.spawn(|cx| f(handle, cx))
4013    }
4014
4015    pub fn spawn_weak<F, Fut, S>(&self, f: F) -> Task<S>
4016    where
4017        F: FnOnce(WeakViewHandle<T>, AsyncAppContext) -> Fut,
4018        Fut: 'static + Future<Output = S>,
4019        S: 'static,
4020    {
4021        let handle = self.weak_handle();
4022        self.app.spawn(|cx| f(handle, cx))
4023    }
4024}
4025
4026pub struct RenderParams {
4027    pub window_id: usize,
4028    pub view_id: usize,
4029    pub titlebar_height: f32,
4030    pub hovered_region_ids: HashSet<MouseRegionId>,
4031    pub clicked_region_ids: Option<(Vec<MouseRegionId>, MouseButton)>,
4032    pub refreshing: bool,
4033}
4034
4035pub struct RenderContext<'a, T: View> {
4036    pub(crate) window_id: usize,
4037    pub(crate) view_id: usize,
4038    pub(crate) view_type: PhantomData<T>,
4039    pub(crate) hovered_region_ids: HashSet<MouseRegionId>,
4040    pub(crate) clicked_region_ids: Option<(Vec<MouseRegionId>, MouseButton)>,
4041    pub app: &'a mut MutableAppContext,
4042    pub titlebar_height: f32,
4043    pub refreshing: bool,
4044}
4045
4046#[derive(Clone, Copy, Default)]
4047pub struct MouseState {
4048    pub hovered: bool,
4049    pub clicked: Option<MouseButton>,
4050}
4051
4052impl<'a, V: View> RenderContext<'a, V> {
4053    fn new(params: RenderParams, app: &'a mut MutableAppContext) -> Self {
4054        Self {
4055            app,
4056            window_id: params.window_id,
4057            view_id: params.view_id,
4058            view_type: PhantomData,
4059            titlebar_height: params.titlebar_height,
4060            hovered_region_ids: params.hovered_region_ids.clone(),
4061            clicked_region_ids: params.clicked_region_ids.clone(),
4062            refreshing: params.refreshing,
4063        }
4064    }
4065
4066    pub fn handle(&self) -> WeakViewHandle<V> {
4067        WeakViewHandle::new(self.window_id, self.view_id)
4068    }
4069
4070    pub fn window_id(&self) -> usize {
4071        self.window_id
4072    }
4073
4074    pub fn view_id(&self) -> usize {
4075        self.view_id
4076    }
4077
4078    pub fn mouse_state<Tag: 'static>(&self, region_id: usize) -> MouseState {
4079        let region_id = MouseRegionId {
4080            view_id: self.view_id,
4081            discriminant: (TypeId::of::<Tag>(), region_id),
4082        };
4083        MouseState {
4084            hovered: self.hovered_region_ids.contains(&region_id),
4085            clicked: self.clicked_region_ids.as_ref().and_then(|(ids, button)| {
4086                if ids.contains(&region_id) {
4087                    Some(*button)
4088                } else {
4089                    None
4090                }
4091            }),
4092        }
4093    }
4094
4095    pub fn element_state<Tag: 'static, T: 'static + Default>(
4096        &mut self,
4097        element_id: usize,
4098    ) -> ElementStateHandle<T> {
4099        let id = ElementStateId {
4100            view_id: self.view_id(),
4101            element_id,
4102            tag: TypeId::of::<Tag>(),
4103        };
4104        self.cx
4105            .element_states
4106            .entry(id)
4107            .or_insert_with(|| Box::new(T::default()));
4108        ElementStateHandle::new(id, self.frame_count, &self.cx.ref_counts)
4109    }
4110}
4111
4112impl AsRef<AppContext> for &AppContext {
4113    fn as_ref(&self) -> &AppContext {
4114        self
4115    }
4116}
4117
4118impl<V: View> Deref for RenderContext<'_, V> {
4119    type Target = MutableAppContext;
4120
4121    fn deref(&self) -> &Self::Target {
4122        self.app
4123    }
4124}
4125
4126impl<V: View> DerefMut for RenderContext<'_, V> {
4127    fn deref_mut(&mut self) -> &mut Self::Target {
4128        self.app
4129    }
4130}
4131
4132impl<V: View> ReadModel for RenderContext<'_, V> {
4133    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
4134        self.app.read_model(handle)
4135    }
4136}
4137
4138impl<V: View> UpdateModel for RenderContext<'_, V> {
4139    fn update_model<T: Entity, O>(
4140        &mut self,
4141        handle: &ModelHandle<T>,
4142        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
4143    ) -> O {
4144        self.app.update_model(handle, update)
4145    }
4146}
4147
4148impl<V: View> ReadView for RenderContext<'_, V> {
4149    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
4150        self.app.read_view(handle)
4151    }
4152}
4153
4154impl<M> AsRef<AppContext> for ViewContext<'_, M> {
4155    fn as_ref(&self) -> &AppContext {
4156        &self.app.cx
4157    }
4158}
4159
4160impl<M> Deref for ViewContext<'_, M> {
4161    type Target = MutableAppContext;
4162
4163    fn deref(&self) -> &Self::Target {
4164        self.app
4165    }
4166}
4167
4168impl<M> DerefMut for ViewContext<'_, M> {
4169    fn deref_mut(&mut self) -> &mut Self::Target {
4170        &mut self.app
4171    }
4172}
4173
4174impl<M> AsMut<MutableAppContext> for ViewContext<'_, M> {
4175    fn as_mut(&mut self) -> &mut MutableAppContext {
4176        self.app
4177    }
4178}
4179
4180impl<V> ReadModel for ViewContext<'_, V> {
4181    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
4182        self.app.read_model(handle)
4183    }
4184}
4185
4186impl<V> UpgradeModelHandle for ViewContext<'_, V> {
4187    fn upgrade_model_handle<T: Entity>(
4188        &self,
4189        handle: &WeakModelHandle<T>,
4190    ) -> Option<ModelHandle<T>> {
4191        self.cx.upgrade_model_handle(handle)
4192    }
4193
4194    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
4195        self.cx.model_handle_is_upgradable(handle)
4196    }
4197
4198    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
4199        self.cx.upgrade_any_model_handle(handle)
4200    }
4201}
4202
4203impl<V> UpgradeViewHandle for ViewContext<'_, V> {
4204    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
4205        self.cx.upgrade_view_handle(handle)
4206    }
4207
4208    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
4209        self.cx.upgrade_any_view_handle(handle)
4210    }
4211}
4212
4213impl<V: View> UpgradeViewHandle for RenderContext<'_, V> {
4214    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
4215        self.cx.upgrade_view_handle(handle)
4216    }
4217
4218    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
4219        self.cx.upgrade_any_view_handle(handle)
4220    }
4221}
4222
4223impl<V: View> UpdateModel for ViewContext<'_, V> {
4224    fn update_model<T: Entity, O>(
4225        &mut self,
4226        handle: &ModelHandle<T>,
4227        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> O,
4228    ) -> O {
4229        self.app.update_model(handle, update)
4230    }
4231}
4232
4233impl<V: View> ReadView for ViewContext<'_, V> {
4234    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
4235        self.app.read_view(handle)
4236    }
4237}
4238
4239impl<V: View> UpdateView for ViewContext<'_, V> {
4240    fn update_view<T, S>(
4241        &mut self,
4242        handle: &ViewHandle<T>,
4243        update: &mut dyn FnMut(&mut T, &mut ViewContext<T>) -> S,
4244    ) -> S
4245    where
4246        T: View,
4247    {
4248        self.app.update_view(handle, update)
4249    }
4250}
4251
4252pub trait Handle<T> {
4253    type Weak: 'static;
4254    fn id(&self) -> usize;
4255    fn location(&self) -> EntityLocation;
4256    fn downgrade(&self) -> Self::Weak;
4257    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
4258    where
4259        Self: Sized;
4260}
4261
4262pub trait WeakHandle {
4263    fn id(&self) -> usize;
4264}
4265
4266#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
4267pub enum EntityLocation {
4268    Model(usize),
4269    View(usize, usize),
4270}
4271
4272pub struct ModelHandle<T: Entity> {
4273    model_id: usize,
4274    model_type: PhantomData<T>,
4275    ref_counts: Arc<Mutex<RefCounts>>,
4276
4277    #[cfg(any(test, feature = "test-support"))]
4278    handle_id: usize,
4279}
4280
4281impl<T: Entity> ModelHandle<T> {
4282    fn new(model_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
4283        ref_counts.lock().inc_model(model_id);
4284
4285        #[cfg(any(test, feature = "test-support"))]
4286        let handle_id = ref_counts
4287            .lock()
4288            .leak_detector
4289            .lock()
4290            .handle_created(Some(type_name::<T>()), model_id);
4291
4292        Self {
4293            model_id,
4294            model_type: PhantomData,
4295            ref_counts: ref_counts.clone(),
4296
4297            #[cfg(any(test, feature = "test-support"))]
4298            handle_id,
4299        }
4300    }
4301
4302    pub fn downgrade(&self) -> WeakModelHandle<T> {
4303        WeakModelHandle::new(self.model_id)
4304    }
4305
4306    pub fn id(&self) -> usize {
4307        self.model_id
4308    }
4309
4310    pub fn read<'a, C: ReadModel>(&self, cx: &'a C) -> &'a T {
4311        cx.read_model(self)
4312    }
4313
4314    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
4315    where
4316        C: ReadModelWith,
4317        F: FnOnce(&T, &AppContext) -> S,
4318    {
4319        let mut read = Some(read);
4320        cx.read_model_with(self, &mut |model, cx| {
4321            let read = read.take().unwrap();
4322            read(model, cx)
4323        })
4324    }
4325
4326    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
4327    where
4328        C: UpdateModel,
4329        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
4330    {
4331        let mut update = Some(update);
4332        cx.update_model(self, &mut |model, cx| {
4333            let update = update.take().unwrap();
4334            update(model, cx)
4335        })
4336    }
4337
4338    #[cfg(any(test, feature = "test-support"))]
4339    pub fn next_notification(&self, cx: &TestAppContext) -> impl Future<Output = ()> {
4340        let (tx, mut rx) = futures::channel::mpsc::unbounded();
4341        let mut cx = cx.cx.borrow_mut();
4342        let subscription = cx.observe(self, move |_, _| {
4343            tx.unbounded_send(()).ok();
4344        });
4345
4346        let duration = if std::env::var("CI").is_ok() {
4347            Duration::from_secs(5)
4348        } else {
4349            Duration::from_secs(1)
4350        };
4351
4352        async move {
4353            let notification = crate::util::timeout(duration, rx.next())
4354                .await
4355                .expect("next notification timed out");
4356            drop(subscription);
4357            notification.expect("model dropped while test was waiting for its next notification")
4358        }
4359    }
4360
4361    #[cfg(any(test, feature = "test-support"))]
4362    pub fn next_event(&self, cx: &TestAppContext) -> impl Future<Output = T::Event>
4363    where
4364        T::Event: Clone,
4365    {
4366        let (tx, mut rx) = futures::channel::mpsc::unbounded();
4367        let mut cx = cx.cx.borrow_mut();
4368        let subscription = cx.subscribe(self, move |_, event, _| {
4369            tx.unbounded_send(event.clone()).ok();
4370        });
4371
4372        let duration = if std::env::var("CI").is_ok() {
4373            Duration::from_secs(5)
4374        } else {
4375            Duration::from_secs(1)
4376        };
4377
4378        cx.foreground.start_waiting();
4379        async move {
4380            let event = crate::util::timeout(duration, rx.next())
4381                .await
4382                .expect("next event timed out");
4383            drop(subscription);
4384            event.expect("model dropped while test was waiting for its next event")
4385        }
4386    }
4387
4388    #[cfg(any(test, feature = "test-support"))]
4389    pub fn condition(
4390        &self,
4391        cx: &TestAppContext,
4392        mut predicate: impl FnMut(&T, &AppContext) -> bool,
4393    ) -> impl Future<Output = ()> {
4394        let (tx, mut rx) = futures::channel::mpsc::unbounded();
4395
4396        let mut cx = cx.cx.borrow_mut();
4397        let subscriptions = (
4398            cx.observe(self, {
4399                let tx = tx.clone();
4400                move |_, _| {
4401                    tx.unbounded_send(()).ok();
4402                }
4403            }),
4404            cx.subscribe(self, {
4405                move |_, _, _| {
4406                    tx.unbounded_send(()).ok();
4407                }
4408            }),
4409        );
4410
4411        let cx = cx.weak_self.as_ref().unwrap().upgrade().unwrap();
4412        let handle = self.downgrade();
4413        let duration = if std::env::var("CI").is_ok() {
4414            Duration::from_secs(5)
4415        } else {
4416            Duration::from_secs(1)
4417        };
4418
4419        async move {
4420            crate::util::timeout(duration, async move {
4421                loop {
4422                    {
4423                        let cx = cx.borrow();
4424                        let cx = cx.as_ref();
4425                        if predicate(
4426                            handle
4427                                .upgrade(cx)
4428                                .expect("model dropped with pending condition")
4429                                .read(cx),
4430                            cx,
4431                        ) {
4432                            break;
4433                        }
4434                    }
4435
4436                    cx.borrow().foreground().start_waiting();
4437                    rx.next()
4438                        .await
4439                        .expect("model dropped with pending condition");
4440                    cx.borrow().foreground().finish_waiting();
4441                }
4442            })
4443            .await
4444            .expect("condition timed out");
4445            drop(subscriptions);
4446        }
4447    }
4448}
4449
4450impl<T: Entity> Clone for ModelHandle<T> {
4451    fn clone(&self) -> Self {
4452        Self::new(self.model_id, &self.ref_counts)
4453    }
4454}
4455
4456impl<T: Entity> PartialEq for ModelHandle<T> {
4457    fn eq(&self, other: &Self) -> bool {
4458        self.model_id == other.model_id
4459    }
4460}
4461
4462impl<T: Entity> Eq for ModelHandle<T> {}
4463
4464impl<T: Entity> PartialEq<WeakModelHandle<T>> for ModelHandle<T> {
4465    fn eq(&self, other: &WeakModelHandle<T>) -> bool {
4466        self.model_id == other.model_id
4467    }
4468}
4469
4470impl<T: Entity> Hash for ModelHandle<T> {
4471    fn hash<H: Hasher>(&self, state: &mut H) {
4472        self.model_id.hash(state);
4473    }
4474}
4475
4476impl<T: Entity> std::borrow::Borrow<usize> for ModelHandle<T> {
4477    fn borrow(&self) -> &usize {
4478        &self.model_id
4479    }
4480}
4481
4482impl<T: Entity> Debug for ModelHandle<T> {
4483    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
4484        f.debug_tuple(&format!("ModelHandle<{}>", type_name::<T>()))
4485            .field(&self.model_id)
4486            .finish()
4487    }
4488}
4489
4490unsafe impl<T: Entity> Send for ModelHandle<T> {}
4491unsafe impl<T: Entity> Sync for ModelHandle<T> {}
4492
4493impl<T: Entity> Drop for ModelHandle<T> {
4494    fn drop(&mut self) {
4495        let mut ref_counts = self.ref_counts.lock();
4496        ref_counts.dec_model(self.model_id);
4497
4498        #[cfg(any(test, feature = "test-support"))]
4499        ref_counts
4500            .leak_detector
4501            .lock()
4502            .handle_dropped(self.model_id, self.handle_id);
4503    }
4504}
4505
4506impl<T: Entity> Handle<T> for ModelHandle<T> {
4507    type Weak = WeakModelHandle<T>;
4508
4509    fn id(&self) -> usize {
4510        self.model_id
4511    }
4512
4513    fn location(&self) -> EntityLocation {
4514        EntityLocation::Model(self.model_id)
4515    }
4516
4517    fn downgrade(&self) -> Self::Weak {
4518        self.downgrade()
4519    }
4520
4521    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
4522    where
4523        Self: Sized,
4524    {
4525        weak.upgrade(cx)
4526    }
4527}
4528
4529pub struct WeakModelHandle<T> {
4530    model_id: usize,
4531    model_type: PhantomData<T>,
4532}
4533
4534impl<T> WeakHandle for WeakModelHandle<T> {
4535    fn id(&self) -> usize {
4536        self.model_id
4537    }
4538}
4539
4540unsafe impl<T> Send for WeakModelHandle<T> {}
4541unsafe impl<T> Sync for WeakModelHandle<T> {}
4542
4543impl<T: Entity> WeakModelHandle<T> {
4544    fn new(model_id: usize) -> Self {
4545        Self {
4546            model_id,
4547            model_type: PhantomData,
4548        }
4549    }
4550
4551    pub fn id(&self) -> usize {
4552        self.model_id
4553    }
4554
4555    pub fn is_upgradable(&self, cx: &impl UpgradeModelHandle) -> bool {
4556        cx.model_handle_is_upgradable(self)
4557    }
4558
4559    pub fn upgrade(&self, cx: &impl UpgradeModelHandle) -> Option<ModelHandle<T>> {
4560        cx.upgrade_model_handle(self)
4561    }
4562}
4563
4564impl<T> Hash for WeakModelHandle<T> {
4565    fn hash<H: Hasher>(&self, state: &mut H) {
4566        self.model_id.hash(state)
4567    }
4568}
4569
4570impl<T> PartialEq for WeakModelHandle<T> {
4571    fn eq(&self, other: &Self) -> bool {
4572        self.model_id == other.model_id
4573    }
4574}
4575
4576impl<T> Eq for WeakModelHandle<T> {}
4577
4578impl<T> Clone for WeakModelHandle<T> {
4579    fn clone(&self) -> Self {
4580        Self {
4581            model_id: self.model_id,
4582            model_type: PhantomData,
4583        }
4584    }
4585}
4586
4587impl<T> Copy for WeakModelHandle<T> {}
4588
4589pub struct ViewHandle<T> {
4590    window_id: usize,
4591    view_id: usize,
4592    view_type: PhantomData<T>,
4593    ref_counts: Arc<Mutex<RefCounts>>,
4594    #[cfg(any(test, feature = "test-support"))]
4595    handle_id: usize,
4596}
4597
4598impl<T: View> ViewHandle<T> {
4599    fn new(window_id: usize, view_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
4600        ref_counts.lock().inc_view(window_id, view_id);
4601        #[cfg(any(test, feature = "test-support"))]
4602        let handle_id = ref_counts
4603            .lock()
4604            .leak_detector
4605            .lock()
4606            .handle_created(Some(type_name::<T>()), view_id);
4607
4608        Self {
4609            window_id,
4610            view_id,
4611            view_type: PhantomData,
4612            ref_counts: ref_counts.clone(),
4613
4614            #[cfg(any(test, feature = "test-support"))]
4615            handle_id,
4616        }
4617    }
4618
4619    pub fn downgrade(&self) -> WeakViewHandle<T> {
4620        WeakViewHandle::new(self.window_id, self.view_id)
4621    }
4622
4623    pub fn window_id(&self) -> usize {
4624        self.window_id
4625    }
4626
4627    pub fn id(&self) -> usize {
4628        self.view_id
4629    }
4630
4631    pub fn read<'a, C: ReadView>(&self, cx: &'a C) -> &'a T {
4632        cx.read_view(self)
4633    }
4634
4635    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
4636    where
4637        C: ReadViewWith,
4638        F: FnOnce(&T, &AppContext) -> S,
4639    {
4640        let mut read = Some(read);
4641        cx.read_view_with(self, &mut |view, cx| {
4642            let read = read.take().unwrap();
4643            read(view, cx)
4644        })
4645    }
4646
4647    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
4648    where
4649        C: UpdateView,
4650        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
4651    {
4652        let mut update = Some(update);
4653        cx.update_view(self, &mut |view, cx| {
4654            let update = update.take().unwrap();
4655            update(view, cx)
4656        })
4657    }
4658
4659    pub fn defer<C, F>(&self, cx: &mut C, update: F)
4660    where
4661        C: AsMut<MutableAppContext>,
4662        F: 'static + FnOnce(&mut T, &mut ViewContext<T>),
4663    {
4664        let this = self.clone();
4665        cx.as_mut().defer(move |cx| {
4666            this.update(cx, |view, cx| update(view, cx));
4667        });
4668    }
4669
4670    pub fn is_focused(&self, cx: &AppContext) -> bool {
4671        cx.focused_view_id(self.window_id)
4672            .map_or(false, |focused_id| focused_id == self.view_id)
4673    }
4674
4675    #[cfg(any(test, feature = "test-support"))]
4676    pub fn next_notification(&self, cx: &TestAppContext) -> impl Future<Output = ()> {
4677        use postage::prelude::{Sink as _, Stream as _};
4678
4679        let (mut tx, mut rx) = postage::mpsc::channel(1);
4680        let mut cx = cx.cx.borrow_mut();
4681        let subscription = cx.observe(self, move |_, _| {
4682            tx.try_send(()).ok();
4683        });
4684
4685        let duration = if std::env::var("CI").is_ok() {
4686            Duration::from_secs(5)
4687        } else {
4688            Duration::from_secs(1)
4689        };
4690
4691        async move {
4692            let notification = crate::util::timeout(duration, rx.recv())
4693                .await
4694                .expect("next notification timed out");
4695            drop(subscription);
4696            notification.expect("model dropped while test was waiting for its next notification")
4697        }
4698    }
4699
4700    #[cfg(any(test, feature = "test-support"))]
4701    pub fn condition(
4702        &self,
4703        cx: &TestAppContext,
4704        mut predicate: impl FnMut(&T, &AppContext) -> bool,
4705    ) -> impl Future<Output = ()> {
4706        use postage::prelude::{Sink as _, Stream as _};
4707
4708        let (tx, mut rx) = postage::mpsc::channel(1024);
4709        let timeout_duration = cx.condition_duration();
4710
4711        let mut cx = cx.cx.borrow_mut();
4712        let subscriptions = self.update(&mut *cx, |_, cx| {
4713            (
4714                cx.observe(self, {
4715                    let mut tx = tx.clone();
4716                    move |_, _, _| {
4717                        tx.blocking_send(()).ok();
4718                    }
4719                }),
4720                cx.subscribe(self, {
4721                    let mut tx = tx.clone();
4722                    move |_, _, _, _| {
4723                        tx.blocking_send(()).ok();
4724                    }
4725                }),
4726            )
4727        });
4728
4729        let cx = cx.weak_self.as_ref().unwrap().upgrade().unwrap();
4730        let handle = self.downgrade();
4731
4732        async move {
4733            crate::util::timeout(timeout_duration, async move {
4734                loop {
4735                    {
4736                        let cx = cx.borrow();
4737                        let cx = cx.as_ref();
4738                        if predicate(
4739                            handle
4740                                .upgrade(cx)
4741                                .expect("view dropped with pending condition")
4742                                .read(cx),
4743                            cx,
4744                        ) {
4745                            break;
4746                        }
4747                    }
4748
4749                    cx.borrow().foreground().start_waiting();
4750                    rx.recv()
4751                        .await
4752                        .expect("view dropped with pending condition");
4753                    cx.borrow().foreground().finish_waiting();
4754                }
4755            })
4756            .await
4757            .expect("condition timed out");
4758            drop(subscriptions);
4759        }
4760    }
4761}
4762
4763impl<T: View> Clone for ViewHandle<T> {
4764    fn clone(&self) -> Self {
4765        ViewHandle::new(self.window_id, self.view_id, &self.ref_counts)
4766    }
4767}
4768
4769impl<T> PartialEq for ViewHandle<T> {
4770    fn eq(&self, other: &Self) -> bool {
4771        self.window_id == other.window_id && self.view_id == other.view_id
4772    }
4773}
4774
4775impl<T> PartialEq<WeakViewHandle<T>> for ViewHandle<T> {
4776    fn eq(&self, other: &WeakViewHandle<T>) -> bool {
4777        self.window_id == other.window_id && self.view_id == other.view_id
4778    }
4779}
4780
4781impl<T> PartialEq<ViewHandle<T>> for WeakViewHandle<T> {
4782    fn eq(&self, other: &ViewHandle<T>) -> bool {
4783        self.window_id == other.window_id && self.view_id == other.view_id
4784    }
4785}
4786
4787impl<T> Eq for ViewHandle<T> {}
4788
4789impl<T> Hash for ViewHandle<T> {
4790    fn hash<H: Hasher>(&self, state: &mut H) {
4791        self.window_id.hash(state);
4792        self.view_id.hash(state);
4793    }
4794}
4795
4796impl<T> Debug for ViewHandle<T> {
4797    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
4798        f.debug_struct(&format!("ViewHandle<{}>", type_name::<T>()))
4799            .field("window_id", &self.window_id)
4800            .field("view_id", &self.view_id)
4801            .finish()
4802    }
4803}
4804
4805impl<T> Drop for ViewHandle<T> {
4806    fn drop(&mut self) {
4807        self.ref_counts
4808            .lock()
4809            .dec_view(self.window_id, self.view_id);
4810        #[cfg(any(test, feature = "test-support"))]
4811        self.ref_counts
4812            .lock()
4813            .leak_detector
4814            .lock()
4815            .handle_dropped(self.view_id, self.handle_id);
4816    }
4817}
4818
4819impl<T: View> Handle<T> for ViewHandle<T> {
4820    type Weak = WeakViewHandle<T>;
4821
4822    fn id(&self) -> usize {
4823        self.view_id
4824    }
4825
4826    fn location(&self) -> EntityLocation {
4827        EntityLocation::View(self.window_id, self.view_id)
4828    }
4829
4830    fn downgrade(&self) -> Self::Weak {
4831        self.downgrade()
4832    }
4833
4834    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
4835    where
4836        Self: Sized,
4837    {
4838        weak.upgrade(cx)
4839    }
4840}
4841
4842pub struct AnyViewHandle {
4843    window_id: usize,
4844    view_id: usize,
4845    view_type: TypeId,
4846    ref_counts: Arc<Mutex<RefCounts>>,
4847
4848    #[cfg(any(test, feature = "test-support"))]
4849    handle_id: usize,
4850}
4851
4852impl AnyViewHandle {
4853    fn new(
4854        window_id: usize,
4855        view_id: usize,
4856        view_type: TypeId,
4857        ref_counts: Arc<Mutex<RefCounts>>,
4858    ) -> Self {
4859        ref_counts.lock().inc_view(window_id, view_id);
4860
4861        #[cfg(any(test, feature = "test-support"))]
4862        let handle_id = ref_counts
4863            .lock()
4864            .leak_detector
4865            .lock()
4866            .handle_created(None, view_id);
4867
4868        Self {
4869            window_id,
4870            view_id,
4871            view_type,
4872            ref_counts,
4873            #[cfg(any(test, feature = "test-support"))]
4874            handle_id,
4875        }
4876    }
4877
4878    pub fn id(&self) -> usize {
4879        self.view_id
4880    }
4881
4882    pub fn is<T: 'static>(&self) -> bool {
4883        TypeId::of::<T>() == self.view_type
4884    }
4885
4886    pub fn is_focused(&self, cx: &AppContext) -> bool {
4887        cx.focused_view_id(self.window_id)
4888            .map_or(false, |focused_id| focused_id == self.view_id)
4889    }
4890
4891    pub fn downcast<T: View>(self) -> Option<ViewHandle<T>> {
4892        if self.is::<T>() {
4893            let result = Some(ViewHandle {
4894                window_id: self.window_id,
4895                view_id: self.view_id,
4896                ref_counts: self.ref_counts.clone(),
4897                view_type: PhantomData,
4898                #[cfg(any(test, feature = "test-support"))]
4899                handle_id: self.handle_id,
4900            });
4901            unsafe {
4902                Arc::decrement_strong_count(Arc::as_ptr(&self.ref_counts));
4903            }
4904            std::mem::forget(self);
4905            result
4906        } else {
4907            None
4908        }
4909    }
4910
4911    pub fn downgrade(&self) -> AnyWeakViewHandle {
4912        AnyWeakViewHandle {
4913            window_id: self.window_id,
4914            view_id: self.view_id,
4915            view_type: self.view_type,
4916        }
4917    }
4918
4919    pub fn view_type(&self) -> TypeId {
4920        self.view_type
4921    }
4922
4923    pub fn debug_json(&self, cx: &AppContext) -> serde_json::Value {
4924        cx.views
4925            .get(&(self.window_id, self.view_id))
4926            .map_or_else(|| serde_json::Value::Null, |view| view.debug_json(cx))
4927    }
4928}
4929
4930impl Clone for AnyViewHandle {
4931    fn clone(&self) -> Self {
4932        Self::new(
4933            self.window_id,
4934            self.view_id,
4935            self.view_type,
4936            self.ref_counts.clone(),
4937        )
4938    }
4939}
4940
4941impl From<&AnyViewHandle> for AnyViewHandle {
4942    fn from(handle: &AnyViewHandle) -> Self {
4943        handle.clone()
4944    }
4945}
4946
4947impl<T: View> From<&ViewHandle<T>> for AnyViewHandle {
4948    fn from(handle: &ViewHandle<T>) -> Self {
4949        Self::new(
4950            handle.window_id,
4951            handle.view_id,
4952            TypeId::of::<T>(),
4953            handle.ref_counts.clone(),
4954        )
4955    }
4956}
4957
4958impl<T: View> From<ViewHandle<T>> for AnyViewHandle {
4959    fn from(handle: ViewHandle<T>) -> Self {
4960        let any_handle = AnyViewHandle {
4961            window_id: handle.window_id,
4962            view_id: handle.view_id,
4963            view_type: TypeId::of::<T>(),
4964            ref_counts: handle.ref_counts.clone(),
4965            #[cfg(any(test, feature = "test-support"))]
4966            handle_id: handle.handle_id,
4967        };
4968
4969        unsafe {
4970            Arc::decrement_strong_count(Arc::as_ptr(&handle.ref_counts));
4971        }
4972        std::mem::forget(handle);
4973        any_handle
4974    }
4975}
4976
4977impl Drop for AnyViewHandle {
4978    fn drop(&mut self) {
4979        self.ref_counts
4980            .lock()
4981            .dec_view(self.window_id, self.view_id);
4982        #[cfg(any(test, feature = "test-support"))]
4983        self.ref_counts
4984            .lock()
4985            .leak_detector
4986            .lock()
4987            .handle_dropped(self.view_id, self.handle_id);
4988    }
4989}
4990
4991pub struct AnyModelHandle {
4992    model_id: usize,
4993    model_type: TypeId,
4994    ref_counts: Arc<Mutex<RefCounts>>,
4995
4996    #[cfg(any(test, feature = "test-support"))]
4997    handle_id: usize,
4998}
4999
5000impl AnyModelHandle {
5001    fn new(model_id: usize, model_type: TypeId, ref_counts: Arc<Mutex<RefCounts>>) -> Self {
5002        ref_counts.lock().inc_model(model_id);
5003
5004        #[cfg(any(test, feature = "test-support"))]
5005        let handle_id = ref_counts
5006            .lock()
5007            .leak_detector
5008            .lock()
5009            .handle_created(None, model_id);
5010
5011        Self {
5012            model_id,
5013            model_type,
5014            ref_counts,
5015
5016            #[cfg(any(test, feature = "test-support"))]
5017            handle_id,
5018        }
5019    }
5020
5021    pub fn downcast<T: Entity>(self) -> Option<ModelHandle<T>> {
5022        if self.is::<T>() {
5023            let result = Some(ModelHandle {
5024                model_id: self.model_id,
5025                model_type: PhantomData,
5026                ref_counts: self.ref_counts.clone(),
5027
5028                #[cfg(any(test, feature = "test-support"))]
5029                handle_id: self.handle_id,
5030            });
5031            unsafe {
5032                Arc::decrement_strong_count(Arc::as_ptr(&self.ref_counts));
5033            }
5034            std::mem::forget(self);
5035            result
5036        } else {
5037            None
5038        }
5039    }
5040
5041    pub fn downgrade(&self) -> AnyWeakModelHandle {
5042        AnyWeakModelHandle {
5043            model_id: self.model_id,
5044            model_type: self.model_type,
5045        }
5046    }
5047
5048    pub fn is<T: Entity>(&self) -> bool {
5049        self.model_type == TypeId::of::<T>()
5050    }
5051
5052    pub fn model_type(&self) -> TypeId {
5053        self.model_type
5054    }
5055}
5056
5057impl<T: Entity> From<ModelHandle<T>> for AnyModelHandle {
5058    fn from(handle: ModelHandle<T>) -> Self {
5059        Self::new(
5060            handle.model_id,
5061            TypeId::of::<T>(),
5062            handle.ref_counts.clone(),
5063        )
5064    }
5065}
5066
5067impl Clone for AnyModelHandle {
5068    fn clone(&self) -> Self {
5069        Self::new(self.model_id, self.model_type, self.ref_counts.clone())
5070    }
5071}
5072
5073impl Drop for AnyModelHandle {
5074    fn drop(&mut self) {
5075        let mut ref_counts = self.ref_counts.lock();
5076        ref_counts.dec_model(self.model_id);
5077
5078        #[cfg(any(test, feature = "test-support"))]
5079        ref_counts
5080            .leak_detector
5081            .lock()
5082            .handle_dropped(self.model_id, self.handle_id);
5083    }
5084}
5085
5086#[derive(Hash, PartialEq, Eq, Debug)]
5087pub struct AnyWeakModelHandle {
5088    model_id: usize,
5089    model_type: TypeId,
5090}
5091
5092impl AnyWeakModelHandle {
5093    pub fn upgrade(&self, cx: &impl UpgradeModelHandle) -> Option<AnyModelHandle> {
5094        cx.upgrade_any_model_handle(self)
5095    }
5096    pub fn model_type(&self) -> TypeId {
5097        self.model_type
5098    }
5099
5100    fn is<T: 'static>(&self) -> bool {
5101        TypeId::of::<T>() == self.model_type
5102    }
5103
5104    pub fn downcast<T: Entity>(&self) -> Option<WeakModelHandle<T>> {
5105        if self.is::<T>() {
5106            let result = Some(WeakModelHandle {
5107                model_id: self.model_id,
5108                model_type: PhantomData,
5109            });
5110
5111            result
5112        } else {
5113            None
5114        }
5115    }
5116}
5117
5118impl<T: Entity> From<WeakModelHandle<T>> for AnyWeakModelHandle {
5119    fn from(handle: WeakModelHandle<T>) -> Self {
5120        AnyWeakModelHandle {
5121            model_id: handle.model_id,
5122            model_type: TypeId::of::<T>(),
5123        }
5124    }
5125}
5126
5127#[derive(Debug)]
5128pub struct WeakViewHandle<T> {
5129    window_id: usize,
5130    view_id: usize,
5131    view_type: PhantomData<T>,
5132}
5133
5134impl<T> WeakHandle for WeakViewHandle<T> {
5135    fn id(&self) -> usize {
5136        self.view_id
5137    }
5138}
5139
5140impl<T: View> WeakViewHandle<T> {
5141    fn new(window_id: usize, view_id: usize) -> Self {
5142        Self {
5143            window_id,
5144            view_id,
5145            view_type: PhantomData,
5146        }
5147    }
5148
5149    pub fn id(&self) -> usize {
5150        self.view_id
5151    }
5152
5153    pub fn window_id(&self) -> usize {
5154        self.window_id
5155    }
5156
5157    pub fn upgrade(&self, cx: &impl UpgradeViewHandle) -> Option<ViewHandle<T>> {
5158        cx.upgrade_view_handle(self)
5159    }
5160}
5161
5162impl<T> Clone for WeakViewHandle<T> {
5163    fn clone(&self) -> Self {
5164        Self {
5165            window_id: self.window_id,
5166            view_id: self.view_id,
5167            view_type: PhantomData,
5168        }
5169    }
5170}
5171
5172impl<T> PartialEq for WeakViewHandle<T> {
5173    fn eq(&self, other: &Self) -> bool {
5174        self.window_id == other.window_id && self.view_id == other.view_id
5175    }
5176}
5177
5178impl<T> Eq for WeakViewHandle<T> {}
5179
5180impl<T> Hash for WeakViewHandle<T> {
5181    fn hash<H: Hasher>(&self, state: &mut H) {
5182        self.window_id.hash(state);
5183        self.view_id.hash(state);
5184    }
5185}
5186
5187pub struct AnyWeakViewHandle {
5188    window_id: usize,
5189    view_id: usize,
5190    view_type: TypeId,
5191}
5192
5193impl AnyWeakViewHandle {
5194    pub fn upgrade(&self, cx: &impl UpgradeViewHandle) -> Option<AnyViewHandle> {
5195        cx.upgrade_any_view_handle(self)
5196    }
5197}
5198
5199impl<T: View> From<WeakViewHandle<T>> for AnyWeakViewHandle {
5200    fn from(handle: WeakViewHandle<T>) -> Self {
5201        AnyWeakViewHandle {
5202            window_id: handle.window_id,
5203            view_id: handle.view_id,
5204            view_type: TypeId::of::<T>(),
5205        }
5206    }
5207}
5208
5209#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
5210pub struct ElementStateId {
5211    view_id: usize,
5212    element_id: usize,
5213    tag: TypeId,
5214}
5215
5216pub struct ElementStateHandle<T> {
5217    value_type: PhantomData<T>,
5218    id: ElementStateId,
5219    ref_counts: Weak<Mutex<RefCounts>>,
5220}
5221
5222impl<T: 'static> ElementStateHandle<T> {
5223    fn new(id: ElementStateId, frame_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
5224        ref_counts.lock().inc_element_state(id, frame_id);
5225        Self {
5226            value_type: PhantomData,
5227            id,
5228            ref_counts: Arc::downgrade(ref_counts),
5229        }
5230    }
5231
5232    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
5233        cx.element_states
5234            .get(&self.id)
5235            .unwrap()
5236            .downcast_ref()
5237            .unwrap()
5238    }
5239
5240    pub fn update<C, R>(&self, cx: &mut C, f: impl FnOnce(&mut T, &mut C) -> R) -> R
5241    where
5242        C: DerefMut<Target = MutableAppContext>,
5243    {
5244        let mut element_state = cx.deref_mut().cx.element_states.remove(&self.id).unwrap();
5245        let result = f(element_state.downcast_mut().unwrap(), cx);
5246        cx.deref_mut()
5247            .cx
5248            .element_states
5249            .insert(self.id, element_state);
5250        result
5251    }
5252}
5253
5254impl<T> Drop for ElementStateHandle<T> {
5255    fn drop(&mut self) {
5256        if let Some(ref_counts) = self.ref_counts.upgrade() {
5257            ref_counts.lock().dec_element_state(self.id);
5258        }
5259    }
5260}
5261
5262#[must_use]
5263pub enum Subscription {
5264    Subscription {
5265        id: usize,
5266        entity_id: usize,
5267        subscriptions: Option<Weak<Mapping<usize, SubscriptionCallback>>>,
5268    },
5269    GlobalSubscription {
5270        id: usize,
5271        type_id: TypeId,
5272        subscriptions: Option<Weak<Mapping<TypeId, GlobalSubscriptionCallback>>>,
5273    },
5274    Observation {
5275        id: usize,
5276        entity_id: usize,
5277        observations: Option<Weak<Mapping<usize, ObservationCallback>>>,
5278    },
5279    GlobalObservation {
5280        id: usize,
5281        type_id: TypeId,
5282        observations: Option<Weak<Mapping<TypeId, GlobalObservationCallback>>>,
5283    },
5284    FocusObservation {
5285        id: usize,
5286        view_id: usize,
5287        observations: Option<Weak<Mapping<usize, FocusObservationCallback>>>,
5288    },
5289    WindowActivationObservation {
5290        id: usize,
5291        window_id: usize,
5292        observations: Option<Weak<Mapping<usize, WindowActivationCallback>>>,
5293    },
5294    WindowFullscreenObservation {
5295        id: usize,
5296        window_id: usize,
5297        observations: Option<Weak<Mapping<usize, WindowFullscreenCallback>>>,
5298    },
5299
5300    ReleaseObservation {
5301        id: usize,
5302        entity_id: usize,
5303        #[allow(clippy::type_complexity)]
5304        observations:
5305            Option<Weak<Mutex<HashMap<usize, BTreeMap<usize, ReleaseObservationCallback>>>>>,
5306    },
5307    ActionObservation {
5308        id: usize,
5309        observations: Option<Weak<Mutex<BTreeMap<usize, ActionObservationCallback>>>>,
5310    },
5311}
5312
5313impl Subscription {
5314    pub fn detach(&mut self) {
5315        match self {
5316            Subscription::Subscription { subscriptions, .. } => {
5317                subscriptions.take();
5318            }
5319            Subscription::GlobalSubscription { subscriptions, .. } => {
5320                subscriptions.take();
5321            }
5322            Subscription::Observation { observations, .. } => {
5323                observations.take();
5324            }
5325            Subscription::GlobalObservation { observations, .. } => {
5326                observations.take();
5327            }
5328            Subscription::ReleaseObservation { observations, .. } => {
5329                observations.take();
5330            }
5331            Subscription::FocusObservation { observations, .. } => {
5332                observations.take();
5333            }
5334            Subscription::ActionObservation { observations, .. } => {
5335                observations.take();
5336            }
5337            Subscription::WindowActivationObservation { observations, .. } => {
5338                observations.take();
5339            }
5340            Subscription::WindowFullscreenObservation { observations, .. } => {
5341                observations.take();
5342            }
5343        }
5344    }
5345}
5346
5347impl Drop for Subscription {
5348    fn drop(&mut self) {
5349        match self {
5350            Subscription::Subscription {
5351                id,
5352                entity_id,
5353                subscriptions,
5354            } => {
5355                if let Some(subscriptions) = subscriptions.as_ref().and_then(Weak::upgrade) {
5356                    match subscriptions
5357                        .lock()
5358                        .entry(*entity_id)
5359                        .or_default()
5360                        .entry(*id)
5361                    {
5362                        btree_map::Entry::Vacant(entry) => {
5363                            entry.insert(None);
5364                        }
5365                        btree_map::Entry::Occupied(entry) => {
5366                            entry.remove();
5367                        }
5368                    }
5369                }
5370            }
5371            Subscription::GlobalSubscription {
5372                id,
5373                type_id,
5374                subscriptions,
5375            } => {
5376                if let Some(subscriptions) = subscriptions.as_ref().and_then(Weak::upgrade) {
5377                    match subscriptions.lock().entry(*type_id).or_default().entry(*id) {
5378                        btree_map::Entry::Vacant(entry) => {
5379                            entry.insert(None);
5380                        }
5381                        btree_map::Entry::Occupied(entry) => {
5382                            entry.remove();
5383                        }
5384                    }
5385                }
5386            }
5387            Subscription::Observation {
5388                id,
5389                entity_id,
5390                observations,
5391            } => {
5392                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5393                    match observations
5394                        .lock()
5395                        .entry(*entity_id)
5396                        .or_default()
5397                        .entry(*id)
5398                    {
5399                        btree_map::Entry::Vacant(entry) => {
5400                            entry.insert(None);
5401                        }
5402                        btree_map::Entry::Occupied(entry) => {
5403                            entry.remove();
5404                        }
5405                    }
5406                }
5407            }
5408            Subscription::GlobalObservation {
5409                id,
5410                type_id,
5411                observations,
5412            } => {
5413                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5414                    match observations.lock().entry(*type_id).or_default().entry(*id) {
5415                        collections::btree_map::Entry::Vacant(entry) => {
5416                            entry.insert(None);
5417                        }
5418                        collections::btree_map::Entry::Occupied(entry) => {
5419                            entry.remove();
5420                        }
5421                    }
5422                }
5423            }
5424            Subscription::ReleaseObservation {
5425                id,
5426                entity_id,
5427                observations,
5428            } => {
5429                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5430                    if let Some(observations) = observations.lock().get_mut(entity_id) {
5431                        observations.remove(id);
5432                    }
5433                }
5434            }
5435            Subscription::FocusObservation {
5436                id,
5437                view_id,
5438                observations,
5439            } => {
5440                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5441                    match observations.lock().entry(*view_id).or_default().entry(*id) {
5442                        btree_map::Entry::Vacant(entry) => {
5443                            entry.insert(None);
5444                        }
5445                        btree_map::Entry::Occupied(entry) => {
5446                            entry.remove();
5447                        }
5448                    }
5449                }
5450            }
5451            Subscription::ActionObservation { id, observations } => {
5452                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5453                    observations.lock().remove(id);
5454                }
5455            }
5456            Subscription::WindowActivationObservation {
5457                id,
5458                window_id,
5459                observations,
5460            } => {
5461                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5462                    match observations
5463                        .lock()
5464                        .entry(*window_id)
5465                        .or_default()
5466                        .entry(*id)
5467                    {
5468                        btree_map::Entry::Vacant(entry) => {
5469                            entry.insert(None);
5470                        }
5471                        btree_map::Entry::Occupied(entry) => {
5472                            entry.remove();
5473                        }
5474                    }
5475                }
5476            }
5477            Subscription::WindowFullscreenObservation {
5478                id,
5479                window_id,
5480                observations,
5481            } => {
5482                if let Some(observations) = observations.as_ref().and_then(Weak::upgrade) {
5483                    match observations
5484                        .lock()
5485                        .entry(*window_id)
5486                        .or_default()
5487                        .entry(*id)
5488                    {
5489                        btree_map::Entry::Vacant(entry) => {
5490                            entry.insert(None);
5491                        }
5492                        btree_map::Entry::Occupied(entry) => {
5493                            entry.remove();
5494                        }
5495                    }
5496                }
5497            }
5498        }
5499    }
5500}
5501
5502lazy_static! {
5503    static ref LEAK_BACKTRACE: bool =
5504        std::env::var("LEAK_BACKTRACE").map_or(false, |b| !b.is_empty());
5505}
5506
5507#[cfg(any(test, feature = "test-support"))]
5508#[derive(Default)]
5509pub struct LeakDetector {
5510    next_handle_id: usize,
5511    #[allow(clippy::type_complexity)]
5512    handle_backtraces: HashMap<
5513        usize,
5514        (
5515            Option<&'static str>,
5516            HashMap<usize, Option<backtrace::Backtrace>>,
5517        ),
5518    >,
5519}
5520
5521#[cfg(any(test, feature = "test-support"))]
5522impl LeakDetector {
5523    fn handle_created(&mut self, type_name: Option<&'static str>, entity_id: usize) -> usize {
5524        let handle_id = post_inc(&mut self.next_handle_id);
5525        let entry = self.handle_backtraces.entry(entity_id).or_default();
5526        let backtrace = if *LEAK_BACKTRACE {
5527            Some(backtrace::Backtrace::new_unresolved())
5528        } else {
5529            None
5530        };
5531        if let Some(type_name) = type_name {
5532            entry.0.get_or_insert(type_name);
5533        }
5534        entry.1.insert(handle_id, backtrace);
5535        handle_id
5536    }
5537
5538    fn handle_dropped(&mut self, entity_id: usize, handle_id: usize) {
5539        if let Some((_, backtraces)) = self.handle_backtraces.get_mut(&entity_id) {
5540            assert!(backtraces.remove(&handle_id).is_some());
5541            if backtraces.is_empty() {
5542                self.handle_backtraces.remove(&entity_id);
5543            }
5544        }
5545    }
5546
5547    pub fn assert_dropped(&mut self, entity_id: usize) {
5548        if let Some((type_name, backtraces)) = self.handle_backtraces.get_mut(&entity_id) {
5549            for trace in backtraces.values_mut().flatten() {
5550                trace.resolve();
5551                eprintln!("{:?}", crate::util::CwdBacktrace(trace));
5552            }
5553
5554            let hint = if *LEAK_BACKTRACE {
5555                ""
5556            } else {
5557                " – set LEAK_BACKTRACE=1 for more information"
5558            };
5559
5560            panic!(
5561                "{} handles to {} {} still exist{}",
5562                backtraces.len(),
5563                type_name.unwrap_or("entity"),
5564                entity_id,
5565                hint
5566            );
5567        }
5568    }
5569
5570    pub fn detect(&mut self) {
5571        let mut found_leaks = false;
5572        for (id, (type_name, backtraces)) in self.handle_backtraces.iter_mut() {
5573            eprintln!(
5574                "leaked {} handles to {} {}",
5575                backtraces.len(),
5576                type_name.unwrap_or("entity"),
5577                id
5578            );
5579            for trace in backtraces.values_mut().flatten() {
5580                trace.resolve();
5581                eprintln!("{:?}", crate::util::CwdBacktrace(trace));
5582            }
5583            found_leaks = true;
5584        }
5585
5586        let hint = if *LEAK_BACKTRACE {
5587            ""
5588        } else {
5589            " – set LEAK_BACKTRACE=1 for more information"
5590        };
5591        assert!(!found_leaks, "detected leaked handles{}", hint);
5592    }
5593}
5594
5595#[derive(Default)]
5596struct RefCounts {
5597    entity_counts: HashMap<usize, usize>,
5598    element_state_counts: HashMap<ElementStateId, ElementStateRefCount>,
5599    dropped_models: HashSet<usize>,
5600    dropped_views: HashSet<(usize, usize)>,
5601    dropped_element_states: HashSet<ElementStateId>,
5602
5603    #[cfg(any(test, feature = "test-support"))]
5604    leak_detector: Arc<Mutex<LeakDetector>>,
5605}
5606
5607struct ElementStateRefCount {
5608    ref_count: usize,
5609    frame_id: usize,
5610}
5611
5612impl RefCounts {
5613    fn inc_model(&mut self, model_id: usize) {
5614        match self.entity_counts.entry(model_id) {
5615            Entry::Occupied(mut entry) => {
5616                *entry.get_mut() += 1;
5617            }
5618            Entry::Vacant(entry) => {
5619                entry.insert(1);
5620                self.dropped_models.remove(&model_id);
5621            }
5622        }
5623    }
5624
5625    fn inc_view(&mut self, window_id: usize, view_id: usize) {
5626        match self.entity_counts.entry(view_id) {
5627            Entry::Occupied(mut entry) => *entry.get_mut() += 1,
5628            Entry::Vacant(entry) => {
5629                entry.insert(1);
5630                self.dropped_views.remove(&(window_id, view_id));
5631            }
5632        }
5633    }
5634
5635    fn inc_element_state(&mut self, id: ElementStateId, frame_id: usize) {
5636        match self.element_state_counts.entry(id) {
5637            Entry::Occupied(mut entry) => {
5638                let entry = entry.get_mut();
5639                if entry.frame_id == frame_id || entry.ref_count >= 2 {
5640                    panic!("used the same element state more than once in the same frame");
5641                }
5642                entry.ref_count += 1;
5643                entry.frame_id = frame_id;
5644            }
5645            Entry::Vacant(entry) => {
5646                entry.insert(ElementStateRefCount {
5647                    ref_count: 1,
5648                    frame_id,
5649                });
5650                self.dropped_element_states.remove(&id);
5651            }
5652        }
5653    }
5654
5655    fn dec_model(&mut self, model_id: usize) {
5656        let count = self.entity_counts.get_mut(&model_id).unwrap();
5657        *count -= 1;
5658        if *count == 0 {
5659            self.entity_counts.remove(&model_id);
5660            self.dropped_models.insert(model_id);
5661        }
5662    }
5663
5664    fn dec_view(&mut self, window_id: usize, view_id: usize) {
5665        let count = self.entity_counts.get_mut(&view_id).unwrap();
5666        *count -= 1;
5667        if *count == 0 {
5668            self.entity_counts.remove(&view_id);
5669            self.dropped_views.insert((window_id, view_id));
5670        }
5671    }
5672
5673    fn dec_element_state(&mut self, id: ElementStateId) {
5674        let entry = self.element_state_counts.get_mut(&id).unwrap();
5675        entry.ref_count -= 1;
5676        if entry.ref_count == 0 {
5677            self.element_state_counts.remove(&id);
5678            self.dropped_element_states.insert(id);
5679        }
5680    }
5681
5682    fn is_entity_alive(&self, entity_id: usize) -> bool {
5683        self.entity_counts.contains_key(&entity_id)
5684    }
5685
5686    fn take_dropped(
5687        &mut self,
5688    ) -> (
5689        HashSet<usize>,
5690        HashSet<(usize, usize)>,
5691        HashSet<ElementStateId>,
5692    ) {
5693        (
5694            std::mem::take(&mut self.dropped_models),
5695            std::mem::take(&mut self.dropped_views),
5696            std::mem::take(&mut self.dropped_element_states),
5697        )
5698    }
5699}
5700
5701#[cfg(test)]
5702mod tests {
5703    use super::*;
5704    use crate::{actions, elements::*, impl_actions, MouseButton, MouseButtonEvent};
5705    use serde::Deserialize;
5706    use smol::future::poll_once;
5707    use std::{
5708        cell::Cell,
5709        sync::atomic::{AtomicBool, AtomicUsize, Ordering::SeqCst},
5710    };
5711
5712    #[crate::test(self)]
5713    fn test_model_handles(cx: &mut MutableAppContext) {
5714        struct Model {
5715            other: Option<ModelHandle<Model>>,
5716            events: Vec<String>,
5717        }
5718
5719        impl Entity for Model {
5720            type Event = usize;
5721        }
5722
5723        impl Model {
5724            fn new(other: Option<ModelHandle<Self>>, cx: &mut ModelContext<Self>) -> Self {
5725                if let Some(other) = other.as_ref() {
5726                    cx.observe(other, |me, _, _| {
5727                        me.events.push("notified".into());
5728                    })
5729                    .detach();
5730                    cx.subscribe(other, |me, _, event, _| {
5731                        me.events.push(format!("observed event {}", event));
5732                    })
5733                    .detach();
5734                }
5735
5736                Self {
5737                    other,
5738                    events: Vec::new(),
5739                }
5740            }
5741        }
5742
5743        let handle_1 = cx.add_model(|cx| Model::new(None, cx));
5744        let handle_2 = cx.add_model(|cx| Model::new(Some(handle_1.clone()), cx));
5745        assert_eq!(cx.cx.models.len(), 2);
5746
5747        handle_1.update(cx, |model, cx| {
5748            model.events.push("updated".into());
5749            cx.emit(1);
5750            cx.notify();
5751            cx.emit(2);
5752        });
5753        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
5754        assert_eq!(
5755            handle_2.read(cx).events,
5756            vec![
5757                "observed event 1".to_string(),
5758                "notified".to_string(),
5759                "observed event 2".to_string(),
5760            ]
5761        );
5762
5763        handle_2.update(cx, |model, _| {
5764            drop(handle_1);
5765            model.other.take();
5766        });
5767
5768        assert_eq!(cx.cx.models.len(), 1);
5769        assert!(cx.subscriptions.is_empty());
5770        assert!(cx.observations.is_empty());
5771    }
5772
5773    #[crate::test(self)]
5774    fn test_model_events(cx: &mut MutableAppContext) {
5775        #[derive(Default)]
5776        struct Model {
5777            events: Vec<usize>,
5778        }
5779
5780        impl Entity for Model {
5781            type Event = usize;
5782        }
5783
5784        let handle_1 = cx.add_model(|_| Model::default());
5785        let handle_2 = cx.add_model(|_| Model::default());
5786
5787        handle_1.update(cx, |_, cx| {
5788            cx.subscribe(&handle_2, move |model: &mut Model, emitter, event, cx| {
5789                model.events.push(*event);
5790
5791                cx.subscribe(&emitter, |model, _, event, _| {
5792                    model.events.push(*event * 2);
5793                })
5794                .detach();
5795            })
5796            .detach();
5797        });
5798
5799        handle_2.update(cx, |_, c| c.emit(7));
5800        assert_eq!(handle_1.read(cx).events, vec![7]);
5801
5802        handle_2.update(cx, |_, c| c.emit(5));
5803        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10]);
5804    }
5805
5806    #[crate::test(self)]
5807    fn test_model_emit_before_subscribe_in_same_update_cycle(cx: &mut MutableAppContext) {
5808        #[derive(Default)]
5809        struct Model;
5810
5811        impl Entity for Model {
5812            type Event = ();
5813        }
5814
5815        let events = Rc::new(RefCell::new(Vec::new()));
5816        cx.add_model(|cx| {
5817            drop(cx.subscribe(&cx.handle(), {
5818                let events = events.clone();
5819                move |_, _, _, _| events.borrow_mut().push("dropped before flush")
5820            }));
5821            cx.subscribe(&cx.handle(), {
5822                let events = events.clone();
5823                move |_, _, _, _| events.borrow_mut().push("before emit")
5824            })
5825            .detach();
5826            cx.emit(());
5827            cx.subscribe(&cx.handle(), {
5828                let events = events.clone();
5829                move |_, _, _, _| events.borrow_mut().push("after emit")
5830            })
5831            .detach();
5832            Model
5833        });
5834        assert_eq!(*events.borrow(), ["before emit"]);
5835    }
5836
5837    #[crate::test(self)]
5838    fn test_observe_and_notify_from_model(cx: &mut MutableAppContext) {
5839        #[derive(Default)]
5840        struct Model {
5841            count: usize,
5842            events: Vec<usize>,
5843        }
5844
5845        impl Entity for Model {
5846            type Event = ();
5847        }
5848
5849        let handle_1 = cx.add_model(|_| Model::default());
5850        let handle_2 = cx.add_model(|_| Model::default());
5851
5852        handle_1.update(cx, |_, c| {
5853            c.observe(&handle_2, move |model, observed, c| {
5854                model.events.push(observed.read(c).count);
5855                c.observe(&observed, |model, observed, c| {
5856                    model.events.push(observed.read(c).count * 2);
5857                })
5858                .detach();
5859            })
5860            .detach();
5861        });
5862
5863        handle_2.update(cx, |model, c| {
5864            model.count = 7;
5865            c.notify()
5866        });
5867        assert_eq!(handle_1.read(cx).events, vec![7]);
5868
5869        handle_2.update(cx, |model, c| {
5870            model.count = 5;
5871            c.notify()
5872        });
5873        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10])
5874    }
5875
5876    #[crate::test(self)]
5877    fn test_model_notify_before_observe_in_same_update_cycle(cx: &mut MutableAppContext) {
5878        #[derive(Default)]
5879        struct Model;
5880
5881        impl Entity for Model {
5882            type Event = ();
5883        }
5884
5885        let events = Rc::new(RefCell::new(Vec::new()));
5886        cx.add_model(|cx| {
5887            drop(cx.observe(&cx.handle(), {
5888                let events = events.clone();
5889                move |_, _, _| events.borrow_mut().push("dropped before flush")
5890            }));
5891            cx.observe(&cx.handle(), {
5892                let events = events.clone();
5893                move |_, _, _| events.borrow_mut().push("before notify")
5894            })
5895            .detach();
5896            cx.notify();
5897            cx.observe(&cx.handle(), {
5898                let events = events.clone();
5899                move |_, _, _| events.borrow_mut().push("after notify")
5900            })
5901            .detach();
5902            Model
5903        });
5904        assert_eq!(*events.borrow(), ["before notify"]);
5905    }
5906
5907    #[crate::test(self)]
5908    fn test_defer_and_after_window_update(cx: &mut MutableAppContext) {
5909        struct View {
5910            render_count: usize,
5911        }
5912
5913        impl Entity for View {
5914            type Event = usize;
5915        }
5916
5917        impl super::View for View {
5918            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
5919                post_inc(&mut self.render_count);
5920                Empty::new().boxed()
5921            }
5922
5923            fn ui_name() -> &'static str {
5924                "View"
5925            }
5926        }
5927
5928        let (_, view) = cx.add_window(Default::default(), |_| View { render_count: 0 });
5929        let called_defer = Rc::new(AtomicBool::new(false));
5930        let called_after_window_update = Rc::new(AtomicBool::new(false));
5931
5932        view.update(cx, |this, cx| {
5933            assert_eq!(this.render_count, 1);
5934            cx.defer({
5935                let called_defer = called_defer.clone();
5936                move |this, _| {
5937                    assert_eq!(this.render_count, 1);
5938                    called_defer.store(true, SeqCst);
5939                }
5940            });
5941            cx.after_window_update({
5942                let called_after_window_update = called_after_window_update.clone();
5943                move |this, cx| {
5944                    assert_eq!(this.render_count, 2);
5945                    called_after_window_update.store(true, SeqCst);
5946                    cx.notify();
5947                }
5948            });
5949            assert!(!called_defer.load(SeqCst));
5950            assert!(!called_after_window_update.load(SeqCst));
5951            cx.notify();
5952        });
5953
5954        assert!(called_defer.load(SeqCst));
5955        assert!(called_after_window_update.load(SeqCst));
5956        assert_eq!(view.read(cx).render_count, 3);
5957    }
5958
5959    #[crate::test(self)]
5960    fn test_view_handles(cx: &mut MutableAppContext) {
5961        struct View {
5962            other: Option<ViewHandle<View>>,
5963            events: Vec<String>,
5964        }
5965
5966        impl Entity for View {
5967            type Event = usize;
5968        }
5969
5970        impl super::View for View {
5971            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
5972                Empty::new().boxed()
5973            }
5974
5975            fn ui_name() -> &'static str {
5976                "View"
5977            }
5978        }
5979
5980        impl View {
5981            fn new(other: Option<ViewHandle<View>>, cx: &mut ViewContext<Self>) -> Self {
5982                if let Some(other) = other.as_ref() {
5983                    cx.subscribe(other, |me, _, event, _| {
5984                        me.events.push(format!("observed event {}", event));
5985                    })
5986                    .detach();
5987                }
5988                Self {
5989                    other,
5990                    events: Vec::new(),
5991                }
5992            }
5993        }
5994
5995        let (_, root_view) = cx.add_window(Default::default(), |cx| View::new(None, cx));
5996        let handle_1 = cx.add_view(&root_view, |cx| View::new(None, cx));
5997        let handle_2 = cx.add_view(&root_view, |cx| View::new(Some(handle_1.clone()), cx));
5998        assert_eq!(cx.cx.views.len(), 3);
5999
6000        handle_1.update(cx, |view, cx| {
6001            view.events.push("updated".into());
6002            cx.emit(1);
6003            cx.emit(2);
6004        });
6005        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
6006        assert_eq!(
6007            handle_2.read(cx).events,
6008            vec![
6009                "observed event 1".to_string(),
6010                "observed event 2".to_string(),
6011            ]
6012        );
6013
6014        handle_2.update(cx, |view, _| {
6015            drop(handle_1);
6016            view.other.take();
6017        });
6018
6019        assert_eq!(cx.cx.views.len(), 2);
6020        assert!(cx.subscriptions.is_empty());
6021        assert!(cx.observations.is_empty());
6022    }
6023
6024    #[crate::test(self)]
6025    fn test_add_window(cx: &mut MutableAppContext) {
6026        struct View {
6027            mouse_down_count: Arc<AtomicUsize>,
6028        }
6029
6030        impl Entity for View {
6031            type Event = ();
6032        }
6033
6034        impl super::View for View {
6035            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6036                let mouse_down_count = self.mouse_down_count.clone();
6037                EventHandler::new(Empty::new().boxed())
6038                    .on_mouse_down(move |_| {
6039                        mouse_down_count.fetch_add(1, SeqCst);
6040                        true
6041                    })
6042                    .boxed()
6043            }
6044
6045            fn ui_name() -> &'static str {
6046                "View"
6047            }
6048        }
6049
6050        let mouse_down_count = Arc::new(AtomicUsize::new(0));
6051        let (window_id, _) = cx.add_window(Default::default(), |_| View {
6052            mouse_down_count: mouse_down_count.clone(),
6053        });
6054        let presenter = cx.presenters_and_platform_windows[&window_id].0.clone();
6055        // Ensure window's root element is in a valid lifecycle state.
6056        presenter.borrow_mut().dispatch_event(
6057            Event::MouseDown(MouseButtonEvent {
6058                position: Default::default(),
6059                button: MouseButton::Left,
6060                ctrl: false,
6061                alt: false,
6062                shift: false,
6063                cmd: false,
6064                click_count: 1,
6065            }),
6066            false,
6067            cx,
6068        );
6069        assert_eq!(mouse_down_count.load(SeqCst), 1);
6070    }
6071
6072    #[crate::test(self)]
6073    fn test_entity_release_hooks(cx: &mut MutableAppContext) {
6074        struct Model {
6075            released: Rc<Cell<bool>>,
6076        }
6077
6078        struct View {
6079            released: Rc<Cell<bool>>,
6080        }
6081
6082        impl Entity for Model {
6083            type Event = ();
6084
6085            fn release(&mut self, _: &mut MutableAppContext) {
6086                self.released.set(true);
6087            }
6088        }
6089
6090        impl Entity for View {
6091            type Event = ();
6092
6093            fn release(&mut self, _: &mut MutableAppContext) {
6094                self.released.set(true);
6095            }
6096        }
6097
6098        impl super::View for View {
6099            fn ui_name() -> &'static str {
6100                "View"
6101            }
6102
6103            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6104                Empty::new().boxed()
6105            }
6106        }
6107
6108        let model_released = Rc::new(Cell::new(false));
6109        let model_release_observed = Rc::new(Cell::new(false));
6110        let view_released = Rc::new(Cell::new(false));
6111        let view_release_observed = Rc::new(Cell::new(false));
6112
6113        let model = cx.add_model(|_| Model {
6114            released: model_released.clone(),
6115        });
6116        let (window_id, view) = cx.add_window(Default::default(), |_| View {
6117            released: view_released.clone(),
6118        });
6119        assert!(!model_released.get());
6120        assert!(!view_released.get());
6121
6122        cx.observe_release(&model, {
6123            let model_release_observed = model_release_observed.clone();
6124            move |_, _| model_release_observed.set(true)
6125        })
6126        .detach();
6127        cx.observe_release(&view, {
6128            let view_release_observed = view_release_observed.clone();
6129            move |_, _| view_release_observed.set(true)
6130        })
6131        .detach();
6132
6133        cx.update(move |_| {
6134            drop(model);
6135        });
6136        assert!(model_released.get());
6137        assert!(model_release_observed.get());
6138
6139        drop(view);
6140        cx.remove_window(window_id);
6141        assert!(view_released.get());
6142        assert!(view_release_observed.get());
6143    }
6144
6145    #[crate::test(self)]
6146    fn test_view_events(cx: &mut MutableAppContext) {
6147        #[derive(Default)]
6148        struct View {
6149            events: Vec<usize>,
6150        }
6151
6152        impl Entity for View {
6153            type Event = usize;
6154        }
6155
6156        impl super::View for View {
6157            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6158                Empty::new().boxed()
6159            }
6160
6161            fn ui_name() -> &'static str {
6162                "View"
6163            }
6164        }
6165
6166        struct Model;
6167
6168        impl Entity for Model {
6169            type Event = usize;
6170        }
6171
6172        let (_, handle_1) = cx.add_window(Default::default(), |_| View::default());
6173        let handle_2 = cx.add_view(&handle_1, |_| View::default());
6174        let handle_3 = cx.add_model(|_| Model);
6175
6176        handle_1.update(cx, |_, cx| {
6177            cx.subscribe(&handle_2, move |me, emitter, event, cx| {
6178                me.events.push(*event);
6179
6180                cx.subscribe(&emitter, |me, _, event, _| {
6181                    me.events.push(*event * 2);
6182                })
6183                .detach();
6184            })
6185            .detach();
6186
6187            cx.subscribe(&handle_3, |me, _, event, _| {
6188                me.events.push(*event);
6189            })
6190            .detach();
6191        });
6192
6193        handle_2.update(cx, |_, c| c.emit(7));
6194        assert_eq!(handle_1.read(cx).events, vec![7]);
6195
6196        handle_2.update(cx, |_, c| c.emit(5));
6197        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10]);
6198
6199        handle_3.update(cx, |_, c| c.emit(9));
6200        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10, 9]);
6201    }
6202
6203    #[crate::test(self)]
6204    fn test_global_events(cx: &mut MutableAppContext) {
6205        #[derive(Clone, Debug, Eq, PartialEq)]
6206        struct GlobalEvent(u64);
6207
6208        let events = Rc::new(RefCell::new(Vec::new()));
6209        let first_subscription;
6210        let second_subscription;
6211
6212        {
6213            let events = events.clone();
6214            first_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
6215                events.borrow_mut().push(("First", e.clone()));
6216            });
6217        }
6218
6219        {
6220            let events = events.clone();
6221            second_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
6222                events.borrow_mut().push(("Second", e.clone()));
6223            });
6224        }
6225
6226        cx.update(|cx| {
6227            cx.emit_global(GlobalEvent(1));
6228            cx.emit_global(GlobalEvent(2));
6229        });
6230
6231        drop(first_subscription);
6232
6233        cx.update(|cx| {
6234            cx.emit_global(GlobalEvent(3));
6235        });
6236
6237        drop(second_subscription);
6238
6239        cx.update(|cx| {
6240            cx.emit_global(GlobalEvent(4));
6241        });
6242
6243        assert_eq!(
6244            &*events.borrow(),
6245            &[
6246                ("First", GlobalEvent(1)),
6247                ("Second", GlobalEvent(1)),
6248                ("First", GlobalEvent(2)),
6249                ("Second", GlobalEvent(2)),
6250                ("Second", GlobalEvent(3)),
6251            ]
6252        );
6253    }
6254
6255    #[crate::test(self)]
6256    fn test_global_events_emitted_before_subscription_in_same_update_cycle(
6257        cx: &mut MutableAppContext,
6258    ) {
6259        let events = Rc::new(RefCell::new(Vec::new()));
6260        cx.update(|cx| {
6261            {
6262                let events = events.clone();
6263                drop(cx.subscribe_global(move |_: &(), _| {
6264                    events.borrow_mut().push("dropped before emit");
6265                }));
6266            }
6267
6268            {
6269                let events = events.clone();
6270                cx.subscribe_global(move |_: &(), _| {
6271                    events.borrow_mut().push("before emit");
6272                })
6273                .detach();
6274            }
6275
6276            cx.emit_global(());
6277
6278            {
6279                let events = events.clone();
6280                cx.subscribe_global(move |_: &(), _| {
6281                    events.borrow_mut().push("after emit");
6282                })
6283                .detach();
6284            }
6285        });
6286
6287        assert_eq!(*events.borrow(), ["before emit"]);
6288    }
6289
6290    #[crate::test(self)]
6291    fn test_global_nested_events(cx: &mut MutableAppContext) {
6292        #[derive(Clone, Debug, Eq, PartialEq)]
6293        struct GlobalEvent(u64);
6294
6295        let events = Rc::new(RefCell::new(Vec::new()));
6296
6297        {
6298            let events = events.clone();
6299            cx.subscribe_global(move |e: &GlobalEvent, cx| {
6300                events.borrow_mut().push(("Outer", e.clone()));
6301
6302                if e.0 == 1 {
6303                    let events = events.clone();
6304                    cx.subscribe_global(move |e: &GlobalEvent, _| {
6305                        events.borrow_mut().push(("Inner", e.clone()));
6306                    })
6307                    .detach();
6308                }
6309            })
6310            .detach();
6311        }
6312
6313        cx.update(|cx| {
6314            cx.emit_global(GlobalEvent(1));
6315            cx.emit_global(GlobalEvent(2));
6316            cx.emit_global(GlobalEvent(3));
6317        });
6318        cx.update(|cx| {
6319            cx.emit_global(GlobalEvent(4));
6320        });
6321
6322        assert_eq!(
6323            &*events.borrow(),
6324            &[
6325                ("Outer", GlobalEvent(1)),
6326                ("Outer", GlobalEvent(2)),
6327                ("Outer", GlobalEvent(3)),
6328                ("Outer", GlobalEvent(4)),
6329                ("Inner", GlobalEvent(4)),
6330            ]
6331        );
6332    }
6333
6334    #[crate::test(self)]
6335    fn test_global(cx: &mut MutableAppContext) {
6336        type Global = usize;
6337
6338        let observation_count = Rc::new(RefCell::new(0));
6339        let subscription = cx.observe_global::<Global, _>({
6340            let observation_count = observation_count.clone();
6341            move |_| {
6342                *observation_count.borrow_mut() += 1;
6343            }
6344        });
6345
6346        assert!(!cx.has_global::<Global>());
6347        assert_eq!(cx.default_global::<Global>(), &0);
6348        assert_eq!(*observation_count.borrow(), 1);
6349        assert!(cx.has_global::<Global>());
6350        assert_eq!(
6351            cx.update_global::<Global, _, _>(|global, _| {
6352                *global = 1;
6353                "Update Result"
6354            }),
6355            "Update Result"
6356        );
6357        assert_eq!(*observation_count.borrow(), 2);
6358        assert_eq!(cx.global::<Global>(), &1);
6359
6360        drop(subscription);
6361        cx.update_global::<Global, _, _>(|global, _| {
6362            *global = 2;
6363        });
6364        assert_eq!(*observation_count.borrow(), 2);
6365
6366        type OtherGlobal = f32;
6367
6368        let observation_count = Rc::new(RefCell::new(0));
6369        cx.observe_global::<OtherGlobal, _>({
6370            let observation_count = observation_count.clone();
6371            move |_| {
6372                *observation_count.borrow_mut() += 1;
6373            }
6374        })
6375        .detach();
6376
6377        assert_eq!(
6378            cx.update_default_global::<OtherGlobal, _, _>(|global, _| {
6379                assert_eq!(global, &0.0);
6380                *global = 2.0;
6381                "Default update result"
6382            }),
6383            "Default update result"
6384        );
6385        assert_eq!(cx.global::<OtherGlobal>(), &2.0);
6386        assert_eq!(*observation_count.borrow(), 1);
6387    }
6388
6389    #[crate::test(self)]
6390    fn test_dropping_subscribers(cx: &mut MutableAppContext) {
6391        struct View;
6392
6393        impl Entity for View {
6394            type Event = ();
6395        }
6396
6397        impl super::View for View {
6398            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6399                Empty::new().boxed()
6400            }
6401
6402            fn ui_name() -> &'static str {
6403                "View"
6404            }
6405        }
6406
6407        struct Model;
6408
6409        impl Entity for Model {
6410            type Event = ();
6411        }
6412
6413        let (_, root_view) = cx.add_window(Default::default(), |_| View);
6414        let observing_view = cx.add_view(&root_view, |_| View);
6415        let emitting_view = cx.add_view(&root_view, |_| View);
6416        let observing_model = cx.add_model(|_| Model);
6417        let observed_model = cx.add_model(|_| Model);
6418
6419        observing_view.update(cx, |_, cx| {
6420            cx.subscribe(&emitting_view, |_, _, _, _| {}).detach();
6421            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
6422        });
6423        observing_model.update(cx, |_, cx| {
6424            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
6425        });
6426
6427        cx.update(|_| {
6428            drop(observing_view);
6429            drop(observing_model);
6430        });
6431
6432        emitting_view.update(cx, |_, cx| cx.emit(()));
6433        observed_model.update(cx, |_, cx| cx.emit(()));
6434    }
6435
6436    #[crate::test(self)]
6437    fn test_view_emit_before_subscribe_in_same_update_cycle(cx: &mut MutableAppContext) {
6438        #[derive(Default)]
6439        struct TestView;
6440
6441        impl Entity for TestView {
6442            type Event = ();
6443        }
6444
6445        impl View for TestView {
6446            fn ui_name() -> &'static str {
6447                "TestView"
6448            }
6449
6450            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6451                Empty::new().boxed()
6452            }
6453        }
6454
6455        let events = Rc::new(RefCell::new(Vec::new()));
6456        cx.add_window(Default::default(), |cx| {
6457            drop(cx.subscribe(&cx.handle(), {
6458                let events = events.clone();
6459                move |_, _, _, _| events.borrow_mut().push("dropped before flush")
6460            }));
6461            cx.subscribe(&cx.handle(), {
6462                let events = events.clone();
6463                move |_, _, _, _| events.borrow_mut().push("before emit")
6464            })
6465            .detach();
6466            cx.emit(());
6467            cx.subscribe(&cx.handle(), {
6468                let events = events.clone();
6469                move |_, _, _, _| events.borrow_mut().push("after emit")
6470            })
6471            .detach();
6472            TestView
6473        });
6474        assert_eq!(*events.borrow(), ["before emit"]);
6475    }
6476
6477    #[crate::test(self)]
6478    fn test_observe_and_notify_from_view(cx: &mut MutableAppContext) {
6479        #[derive(Default)]
6480        struct View {
6481            events: Vec<usize>,
6482        }
6483
6484        impl Entity for View {
6485            type Event = usize;
6486        }
6487
6488        impl super::View for View {
6489            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6490                Empty::new().boxed()
6491            }
6492
6493            fn ui_name() -> &'static str {
6494                "View"
6495            }
6496        }
6497
6498        #[derive(Default)]
6499        struct Model {
6500            count: usize,
6501        }
6502
6503        impl Entity for Model {
6504            type Event = ();
6505        }
6506
6507        let (_, view) = cx.add_window(Default::default(), |_| View::default());
6508        let model = cx.add_model(|_| Model::default());
6509
6510        view.update(cx, |_, c| {
6511            c.observe(&model, |me, observed, c| {
6512                me.events.push(observed.read(c).count)
6513            })
6514            .detach();
6515        });
6516
6517        model.update(cx, |model, c| {
6518            model.count = 11;
6519            c.notify();
6520        });
6521        assert_eq!(view.read(cx).events, vec![11]);
6522    }
6523
6524    #[crate::test(self)]
6525    fn test_view_notify_before_observe_in_same_update_cycle(cx: &mut MutableAppContext) {
6526        #[derive(Default)]
6527        struct TestView;
6528
6529        impl Entity for TestView {
6530            type Event = ();
6531        }
6532
6533        impl View for TestView {
6534            fn ui_name() -> &'static str {
6535                "TestView"
6536            }
6537
6538            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6539                Empty::new().boxed()
6540            }
6541        }
6542
6543        let events = Rc::new(RefCell::new(Vec::new()));
6544        cx.add_window(Default::default(), |cx| {
6545            drop(cx.observe(&cx.handle(), {
6546                let events = events.clone();
6547                move |_, _, _| events.borrow_mut().push("dropped before flush")
6548            }));
6549            cx.observe(&cx.handle(), {
6550                let events = events.clone();
6551                move |_, _, _| events.borrow_mut().push("before notify")
6552            })
6553            .detach();
6554            cx.notify();
6555            cx.observe(&cx.handle(), {
6556                let events = events.clone();
6557                move |_, _, _| events.borrow_mut().push("after notify")
6558            })
6559            .detach();
6560            TestView
6561        });
6562        assert_eq!(*events.borrow(), ["before notify"]);
6563    }
6564
6565    #[crate::test(self)]
6566    fn test_dropping_observers(cx: &mut MutableAppContext) {
6567        struct View;
6568
6569        impl Entity for View {
6570            type Event = ();
6571        }
6572
6573        impl super::View for View {
6574            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6575                Empty::new().boxed()
6576            }
6577
6578            fn ui_name() -> &'static str {
6579                "View"
6580            }
6581        }
6582
6583        struct Model;
6584
6585        impl Entity for Model {
6586            type Event = ();
6587        }
6588
6589        let (_, root_view) = cx.add_window(Default::default(), |_| View);
6590        let observing_view = cx.add_view(root_view, |_| View);
6591        let observing_model = cx.add_model(|_| Model);
6592        let observed_model = cx.add_model(|_| Model);
6593
6594        observing_view.update(cx, |_, cx| {
6595            cx.observe(&observed_model, |_, _, _| {}).detach();
6596        });
6597        observing_model.update(cx, |_, cx| {
6598            cx.observe(&observed_model, |_, _, _| {}).detach();
6599        });
6600
6601        cx.update(|_| {
6602            drop(observing_view);
6603            drop(observing_model);
6604        });
6605
6606        observed_model.update(cx, |_, cx| cx.notify());
6607    }
6608
6609    #[crate::test(self)]
6610    fn test_dropping_subscriptions_during_callback(cx: &mut MutableAppContext) {
6611        struct Model;
6612
6613        impl Entity for Model {
6614            type Event = u64;
6615        }
6616
6617        // Events
6618        let observing_model = cx.add_model(|_| Model);
6619        let observed_model = cx.add_model(|_| Model);
6620
6621        let events = Rc::new(RefCell::new(Vec::new()));
6622
6623        observing_model.update(cx, |_, cx| {
6624            let events = events.clone();
6625            let subscription = Rc::new(RefCell::new(None));
6626            *subscription.borrow_mut() = Some(cx.subscribe(&observed_model, {
6627                let subscription = subscription.clone();
6628                move |_, _, e, _| {
6629                    subscription.borrow_mut().take();
6630                    events.borrow_mut().push(*e);
6631                }
6632            }));
6633        });
6634
6635        observed_model.update(cx, |_, cx| {
6636            cx.emit(1);
6637            cx.emit(2);
6638        });
6639
6640        assert_eq!(*events.borrow(), [1]);
6641
6642        // Global Events
6643        #[derive(Clone, Debug, Eq, PartialEq)]
6644        struct GlobalEvent(u64);
6645
6646        let events = Rc::new(RefCell::new(Vec::new()));
6647
6648        {
6649            let events = events.clone();
6650            let subscription = Rc::new(RefCell::new(None));
6651            *subscription.borrow_mut() = Some(cx.subscribe_global({
6652                let subscription = subscription.clone();
6653                move |e: &GlobalEvent, _| {
6654                    subscription.borrow_mut().take();
6655                    events.borrow_mut().push(e.clone());
6656                }
6657            }));
6658        }
6659
6660        cx.update(|cx| {
6661            cx.emit_global(GlobalEvent(1));
6662            cx.emit_global(GlobalEvent(2));
6663        });
6664
6665        assert_eq!(*events.borrow(), [GlobalEvent(1)]);
6666
6667        // Model Observation
6668        let observing_model = cx.add_model(|_| Model);
6669        let observed_model = cx.add_model(|_| Model);
6670
6671        let observation_count = Rc::new(RefCell::new(0));
6672
6673        observing_model.update(cx, |_, cx| {
6674            let observation_count = observation_count.clone();
6675            let subscription = Rc::new(RefCell::new(None));
6676            *subscription.borrow_mut() = Some(cx.observe(&observed_model, {
6677                let subscription = subscription.clone();
6678                move |_, _, _| {
6679                    subscription.borrow_mut().take();
6680                    *observation_count.borrow_mut() += 1;
6681                }
6682            }));
6683        });
6684
6685        observed_model.update(cx, |_, cx| {
6686            cx.notify();
6687        });
6688
6689        observed_model.update(cx, |_, cx| {
6690            cx.notify();
6691        });
6692
6693        assert_eq!(*observation_count.borrow(), 1);
6694
6695        // View Observation
6696        struct View;
6697
6698        impl Entity for View {
6699            type Event = ();
6700        }
6701
6702        impl super::View for View {
6703            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6704                Empty::new().boxed()
6705            }
6706
6707            fn ui_name() -> &'static str {
6708                "View"
6709            }
6710        }
6711
6712        let (_, root_view) = cx.add_window(Default::default(), |_| View);
6713        let observing_view = cx.add_view(&root_view, |_| View);
6714        let observed_view = cx.add_view(&root_view, |_| View);
6715
6716        let observation_count = Rc::new(RefCell::new(0));
6717        observing_view.update(cx, |_, cx| {
6718            let observation_count = observation_count.clone();
6719            let subscription = Rc::new(RefCell::new(None));
6720            *subscription.borrow_mut() = Some(cx.observe(&observed_view, {
6721                let subscription = subscription.clone();
6722                move |_, _, _| {
6723                    subscription.borrow_mut().take();
6724                    *observation_count.borrow_mut() += 1;
6725                }
6726            }));
6727        });
6728
6729        observed_view.update(cx, |_, cx| {
6730            cx.notify();
6731        });
6732
6733        observed_view.update(cx, |_, cx| {
6734            cx.notify();
6735        });
6736
6737        assert_eq!(*observation_count.borrow(), 1);
6738
6739        // Global Observation
6740        let observation_count = Rc::new(RefCell::new(0));
6741        let subscription = Rc::new(RefCell::new(None));
6742        *subscription.borrow_mut() = Some(cx.observe_global::<(), _>({
6743            let observation_count = observation_count.clone();
6744            let subscription = subscription.clone();
6745            move |_| {
6746                subscription.borrow_mut().take();
6747                *observation_count.borrow_mut() += 1;
6748            }
6749        }));
6750
6751        cx.default_global::<()>();
6752        cx.set_global(());
6753        assert_eq!(*observation_count.borrow(), 1);
6754    }
6755
6756    #[crate::test(self)]
6757    fn test_focus(cx: &mut MutableAppContext) {
6758        struct View {
6759            name: String,
6760            events: Arc<Mutex<Vec<String>>>,
6761        }
6762
6763        impl Entity for View {
6764            type Event = ();
6765        }
6766
6767        impl super::View for View {
6768            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6769                Empty::new().boxed()
6770            }
6771
6772            fn ui_name() -> &'static str {
6773                "View"
6774            }
6775
6776            fn on_focus_in(&mut self, focused: AnyViewHandle, cx: &mut ViewContext<Self>) {
6777                if cx.handle().id() == focused.id() {
6778                    self.events.lock().push(format!("{} focused", &self.name));
6779                }
6780            }
6781
6782            fn on_focus_out(&mut self, blurred: AnyViewHandle, cx: &mut ViewContext<Self>) {
6783                if cx.handle().id() == blurred.id() {
6784                    self.events.lock().push(format!("{} blurred", &self.name));
6785                }
6786            }
6787        }
6788
6789        let view_events: Arc<Mutex<Vec<String>>> = Default::default();
6790        let (_, view_1) = cx.add_window(Default::default(), |_| View {
6791            events: view_events.clone(),
6792            name: "view 1".to_string(),
6793        });
6794        let view_2 = cx.add_view(&view_1, |_| View {
6795            events: view_events.clone(),
6796            name: "view 2".to_string(),
6797        });
6798
6799        let observed_events: Arc<Mutex<Vec<String>>> = Default::default();
6800        view_1.update(cx, |_, cx| {
6801            cx.observe_focus(&view_2, {
6802                let observed_events = observed_events.clone();
6803                move |this, view, focused, cx| {
6804                    let label = if focused { "focus" } else { "blur" };
6805                    observed_events.lock().push(format!(
6806                        "{} observed {}'s {}",
6807                        this.name,
6808                        view.read(cx).name,
6809                        label
6810                    ))
6811                }
6812            })
6813            .detach();
6814        });
6815        view_2.update(cx, |_, cx| {
6816            cx.observe_focus(&view_1, {
6817                let observed_events = observed_events.clone();
6818                move |this, view, focused, cx| {
6819                    let label = if focused { "focus" } else { "blur" };
6820                    observed_events.lock().push(format!(
6821                        "{} observed {}'s {}",
6822                        this.name,
6823                        view.read(cx).name,
6824                        label
6825                    ))
6826                }
6827            })
6828            .detach();
6829        });
6830        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
6831        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
6832
6833        view_1.update(cx, |_, cx| {
6834            // Ensure only the latest focus is honored.
6835            cx.focus(&view_2);
6836            cx.focus(&view_1);
6837            cx.focus(&view_2);
6838        });
6839        assert_eq!(
6840            mem::take(&mut *view_events.lock()),
6841            ["view 1 blurred", "view 2 focused"],
6842        );
6843        assert_eq!(
6844            mem::take(&mut *observed_events.lock()),
6845            [
6846                "view 2 observed view 1's blur",
6847                "view 1 observed view 2's focus"
6848            ]
6849        );
6850
6851        view_1.update(cx, |_, cx| cx.focus(&view_1));
6852        assert_eq!(
6853            mem::take(&mut *view_events.lock()),
6854            ["view 2 blurred", "view 1 focused"],
6855        );
6856        assert_eq!(
6857            mem::take(&mut *observed_events.lock()),
6858            [
6859                "view 1 observed view 2's blur",
6860                "view 2 observed view 1's focus"
6861            ]
6862        );
6863
6864        view_1.update(cx, |_, cx| cx.focus(&view_2));
6865        assert_eq!(
6866            mem::take(&mut *view_events.lock()),
6867            ["view 1 blurred", "view 2 focused"],
6868        );
6869        assert_eq!(
6870            mem::take(&mut *observed_events.lock()),
6871            [
6872                "view 2 observed view 1's blur",
6873                "view 1 observed view 2's focus"
6874            ]
6875        );
6876
6877        view_1.update(cx, |_, _| drop(view_2));
6878        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
6879        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
6880    }
6881
6882    #[crate::test(self)]
6883    fn test_deserialize_actions(cx: &mut MutableAppContext) {
6884        #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
6885        pub struct ComplexAction {
6886            arg: String,
6887            count: usize,
6888        }
6889
6890        actions!(test::something, [SimpleAction]);
6891        impl_actions!(test::something, [ComplexAction]);
6892
6893        cx.add_global_action(move |_: &SimpleAction, _: &mut MutableAppContext| {});
6894        cx.add_global_action(move |_: &ComplexAction, _: &mut MutableAppContext| {});
6895
6896        let action1 = cx
6897            .deserialize_action(
6898                "test::something::ComplexAction",
6899                Some(r#"{"arg": "a", "count": 5}"#),
6900            )
6901            .unwrap();
6902        let action2 = cx
6903            .deserialize_action("test::something::SimpleAction", None)
6904            .unwrap();
6905        assert_eq!(
6906            action1.as_any().downcast_ref::<ComplexAction>().unwrap(),
6907            &ComplexAction {
6908                arg: "a".to_string(),
6909                count: 5,
6910            }
6911        );
6912        assert_eq!(
6913            action2.as_any().downcast_ref::<SimpleAction>().unwrap(),
6914            &SimpleAction
6915        );
6916    }
6917
6918    #[crate::test(self)]
6919    fn test_dispatch_action(cx: &mut MutableAppContext) {
6920        struct ViewA {
6921            id: usize,
6922        }
6923
6924        impl Entity for ViewA {
6925            type Event = ();
6926        }
6927
6928        impl View for ViewA {
6929            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6930                Empty::new().boxed()
6931            }
6932
6933            fn ui_name() -> &'static str {
6934                "View"
6935            }
6936        }
6937
6938        struct ViewB {
6939            id: usize,
6940        }
6941
6942        impl Entity for ViewB {
6943            type Event = ();
6944        }
6945
6946        impl View for ViewB {
6947            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
6948                Empty::new().boxed()
6949            }
6950
6951            fn ui_name() -> &'static str {
6952                "View"
6953            }
6954        }
6955
6956        #[derive(Clone, Default, Deserialize, PartialEq)]
6957        pub struct Action(pub String);
6958
6959        impl_actions!(test, [Action]);
6960
6961        let actions = Rc::new(RefCell::new(Vec::new()));
6962
6963        cx.add_global_action({
6964            let actions = actions.clone();
6965            move |_: &Action, _: &mut MutableAppContext| {
6966                actions.borrow_mut().push("global".to_string());
6967            }
6968        });
6969
6970        cx.add_action({
6971            let actions = actions.clone();
6972            move |view: &mut ViewA, action: &Action, cx| {
6973                assert_eq!(action.0, "bar");
6974                cx.propagate_action();
6975                actions.borrow_mut().push(format!("{} a", view.id));
6976            }
6977        });
6978
6979        cx.add_action({
6980            let actions = actions.clone();
6981            move |view: &mut ViewA, _: &Action, cx| {
6982                if view.id != 1 {
6983                    cx.add_view(|cx| {
6984                        cx.propagate_action(); // Still works on a nested ViewContext
6985                        ViewB { id: 5 }
6986                    });
6987                }
6988                actions.borrow_mut().push(format!("{} b", view.id));
6989            }
6990        });
6991
6992        cx.add_action({
6993            let actions = actions.clone();
6994            move |view: &mut ViewB, _: &Action, cx| {
6995                cx.propagate_action();
6996                actions.borrow_mut().push(format!("{} c", view.id));
6997            }
6998        });
6999
7000        cx.add_action({
7001            let actions = actions.clone();
7002            move |view: &mut ViewB, _: &Action, cx| {
7003                cx.propagate_action();
7004                actions.borrow_mut().push(format!("{} d", view.id));
7005            }
7006        });
7007
7008        cx.capture_action({
7009            let actions = actions.clone();
7010            move |view: &mut ViewA, _: &Action, cx| {
7011                cx.propagate_action();
7012                actions.borrow_mut().push(format!("{} capture", view.id));
7013            }
7014        });
7015
7016        let observed_actions = Rc::new(RefCell::new(Vec::new()));
7017        cx.observe_actions({
7018            let observed_actions = observed_actions.clone();
7019            move |action_id, _| observed_actions.borrow_mut().push(action_id)
7020        })
7021        .detach();
7022
7023        let (window_id, view_1) = cx.add_window(Default::default(), |_| ViewA { id: 1 });
7024        let view_2 = cx.add_view(&view_1, |_| ViewB { id: 2 });
7025        let view_3 = cx.add_view(&view_2, |_| ViewA { id: 3 });
7026        let view_4 = cx.add_view(&view_3, |_| ViewB { id: 4 });
7027
7028        cx.handle_dispatch_action_from_effect(
7029            window_id,
7030            Some(view_4.id()),
7031            &Action("bar".to_string()),
7032        );
7033
7034        assert_eq!(
7035            *actions.borrow(),
7036            vec![
7037                "1 capture",
7038                "3 capture",
7039                "4 d",
7040                "4 c",
7041                "3 b",
7042                "3 a",
7043                "2 d",
7044                "2 c",
7045                "1 b"
7046            ]
7047        );
7048        assert_eq!(*observed_actions.borrow(), [Action::default().id()]);
7049
7050        // Remove view_1, which doesn't propagate the action
7051
7052        let (window_id, view_2) = cx.add_window(Default::default(), |_| ViewB { id: 2 });
7053        let view_3 = cx.add_view(&view_2, |_| ViewA { id: 3 });
7054        let view_4 = cx.add_view(&view_3, |_| ViewB { id: 4 });
7055
7056        actions.borrow_mut().clear();
7057        cx.handle_dispatch_action_from_effect(
7058            window_id,
7059            Some(view_4.id()),
7060            &Action("bar".to_string()),
7061        );
7062
7063        assert_eq!(
7064            *actions.borrow(),
7065            vec![
7066                "3 capture",
7067                "4 d",
7068                "4 c",
7069                "3 b",
7070                "3 a",
7071                "2 d",
7072                "2 c",
7073                "global"
7074            ]
7075        );
7076        assert_eq!(
7077            *observed_actions.borrow(),
7078            [Action::default().id(), Action::default().id()]
7079        );
7080    }
7081
7082    #[crate::test(self)]
7083    fn test_dispatch_keystroke(cx: &mut MutableAppContext) {
7084        #[derive(Clone, Deserialize, PartialEq)]
7085        pub struct Action(String);
7086
7087        impl_actions!(test, [Action]);
7088
7089        struct View {
7090            id: usize,
7091            keymap_context: keymap::Context,
7092        }
7093
7094        impl Entity for View {
7095            type Event = ();
7096        }
7097
7098        impl super::View for View {
7099            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7100                Empty::new().boxed()
7101            }
7102
7103            fn ui_name() -> &'static str {
7104                "View"
7105            }
7106
7107            fn keymap_context(&self, _: &AppContext) -> keymap::Context {
7108                self.keymap_context.clone()
7109            }
7110        }
7111
7112        impl View {
7113            fn new(id: usize) -> Self {
7114                View {
7115                    id,
7116                    keymap_context: keymap::Context::default(),
7117                }
7118            }
7119        }
7120
7121        let mut view_1 = View::new(1);
7122        let mut view_2 = View::new(2);
7123        let mut view_3 = View::new(3);
7124        view_1.keymap_context.set.insert("a".into());
7125        view_2.keymap_context.set.insert("a".into());
7126        view_2.keymap_context.set.insert("b".into());
7127        view_3.keymap_context.set.insert("a".into());
7128        view_3.keymap_context.set.insert("b".into());
7129        view_3.keymap_context.set.insert("c".into());
7130
7131        let (window_id, view_1) = cx.add_window(Default::default(), |_| view_1);
7132        let view_2 = cx.add_view(&view_1, |_| view_2);
7133        let _view_3 = cx.add_view(&view_2, |cx| {
7134            cx.focus_self();
7135            view_3
7136        });
7137
7138        // This keymap's only binding dispatches an action on view 2 because that view will have
7139        // "a" and "b" in its context, but not "c".
7140        cx.add_bindings(vec![keymap::Binding::new(
7141            "a",
7142            Action("a".to_string()),
7143            Some("a && b && !c"),
7144        )]);
7145
7146        cx.add_bindings(vec![keymap::Binding::new(
7147            "b",
7148            Action("b".to_string()),
7149            None,
7150        )]);
7151
7152        let actions = Rc::new(RefCell::new(Vec::new()));
7153        cx.add_action({
7154            let actions = actions.clone();
7155            move |view: &mut View, action: &Action, cx| {
7156                if action.0 == "a" {
7157                    actions.borrow_mut().push(format!("{} a", view.id));
7158                } else {
7159                    actions
7160                        .borrow_mut()
7161                        .push(format!("{} {}", view.id, action.0));
7162                    cx.propagate_action();
7163                }
7164            }
7165        });
7166
7167        cx.add_global_action({
7168            let actions = actions.clone();
7169            move |action: &Action, _| {
7170                actions.borrow_mut().push(format!("global {}", action.0));
7171            }
7172        });
7173
7174        cx.dispatch_keystroke(window_id, &Keystroke::parse("a").unwrap());
7175
7176        assert_eq!(&*actions.borrow(), &["2 a"]);
7177
7178        actions.borrow_mut().clear();
7179
7180        cx.dispatch_keystroke(window_id, &Keystroke::parse("b").unwrap());
7181
7182        assert_eq!(&*actions.borrow(), &["3 b", "2 b", "1 b", "global b"]);
7183    }
7184
7185    #[crate::test(self)]
7186    async fn test_model_condition(cx: &mut TestAppContext) {
7187        struct Counter(usize);
7188
7189        impl super::Entity for Counter {
7190            type Event = ();
7191        }
7192
7193        impl Counter {
7194            fn inc(&mut self, cx: &mut ModelContext<Self>) {
7195                self.0 += 1;
7196                cx.notify();
7197            }
7198        }
7199
7200        let model = cx.add_model(|_| Counter(0));
7201
7202        let condition1 = model.condition(cx, |model, _| model.0 == 2);
7203        let condition2 = model.condition(cx, |model, _| model.0 == 3);
7204        smol::pin!(condition1, condition2);
7205
7206        model.update(cx, |model, cx| model.inc(cx));
7207        assert_eq!(poll_once(&mut condition1).await, None);
7208        assert_eq!(poll_once(&mut condition2).await, None);
7209
7210        model.update(cx, |model, cx| model.inc(cx));
7211        assert_eq!(poll_once(&mut condition1).await, Some(()));
7212        assert_eq!(poll_once(&mut condition2).await, None);
7213
7214        model.update(cx, |model, cx| model.inc(cx));
7215        assert_eq!(poll_once(&mut condition2).await, Some(()));
7216
7217        model.update(cx, |_, cx| cx.notify());
7218    }
7219
7220    #[crate::test(self)]
7221    #[should_panic]
7222    async fn test_model_condition_timeout(cx: &mut TestAppContext) {
7223        struct Model;
7224
7225        impl super::Entity for Model {
7226            type Event = ();
7227        }
7228
7229        let model = cx.add_model(|_| Model);
7230        model.condition(cx, |_, _| false).await;
7231    }
7232
7233    #[crate::test(self)]
7234    #[should_panic(expected = "model dropped with pending condition")]
7235    async fn test_model_condition_panic_on_drop(cx: &mut TestAppContext) {
7236        struct Model;
7237
7238        impl super::Entity for Model {
7239            type Event = ();
7240        }
7241
7242        let model = cx.add_model(|_| Model);
7243        let condition = model.condition(cx, |_, _| false);
7244        cx.update(|_| drop(model));
7245        condition.await;
7246    }
7247
7248    #[crate::test(self)]
7249    async fn test_view_condition(cx: &mut TestAppContext) {
7250        struct Counter(usize);
7251
7252        impl super::Entity for Counter {
7253            type Event = ();
7254        }
7255
7256        impl super::View for Counter {
7257            fn ui_name() -> &'static str {
7258                "test view"
7259            }
7260
7261            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7262                Empty::new().boxed()
7263            }
7264        }
7265
7266        impl Counter {
7267            fn inc(&mut self, cx: &mut ViewContext<Self>) {
7268                self.0 += 1;
7269                cx.notify();
7270            }
7271        }
7272
7273        let (_, view) = cx.add_window(|_| Counter(0));
7274
7275        let condition1 = view.condition(cx, |view, _| view.0 == 2);
7276        let condition2 = view.condition(cx, |view, _| view.0 == 3);
7277        smol::pin!(condition1, condition2);
7278
7279        view.update(cx, |view, cx| view.inc(cx));
7280        assert_eq!(poll_once(&mut condition1).await, None);
7281        assert_eq!(poll_once(&mut condition2).await, None);
7282
7283        view.update(cx, |view, cx| view.inc(cx));
7284        assert_eq!(poll_once(&mut condition1).await, Some(()));
7285        assert_eq!(poll_once(&mut condition2).await, None);
7286
7287        view.update(cx, |view, cx| view.inc(cx));
7288        assert_eq!(poll_once(&mut condition2).await, Some(()));
7289        view.update(cx, |_, cx| cx.notify());
7290    }
7291
7292    #[crate::test(self)]
7293    #[should_panic]
7294    async fn test_view_condition_timeout(cx: &mut TestAppContext) {
7295        struct View;
7296
7297        impl super::Entity for View {
7298            type Event = ();
7299        }
7300
7301        impl super::View for View {
7302            fn ui_name() -> &'static str {
7303                "test view"
7304            }
7305
7306            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7307                Empty::new().boxed()
7308            }
7309        }
7310
7311        let (_, view) = cx.add_window(|_| View);
7312        view.condition(cx, |_, _| false).await;
7313    }
7314
7315    #[crate::test(self)]
7316    #[should_panic(expected = "view dropped with pending condition")]
7317    async fn test_view_condition_panic_on_drop(cx: &mut TestAppContext) {
7318        struct View;
7319
7320        impl super::Entity for View {
7321            type Event = ();
7322        }
7323
7324        impl super::View for View {
7325            fn ui_name() -> &'static str {
7326                "test view"
7327            }
7328
7329            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7330                Empty::new().boxed()
7331            }
7332        }
7333
7334        let (_, root_view) = cx.add_window(|_| View);
7335        let view = cx.add_view(&root_view, |_| View);
7336
7337        let condition = view.condition(cx, |_, _| false);
7338        cx.update(|_| drop(view));
7339        condition.await;
7340    }
7341
7342    #[crate::test(self)]
7343    fn test_refresh_windows(cx: &mut MutableAppContext) {
7344        struct View(usize);
7345
7346        impl super::Entity for View {
7347            type Event = ();
7348        }
7349
7350        impl super::View for View {
7351            fn ui_name() -> &'static str {
7352                "test view"
7353            }
7354
7355            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7356                Empty::new().named(format!("render count: {}", post_inc(&mut self.0)))
7357            }
7358        }
7359
7360        let (window_id, root_view) = cx.add_window(Default::default(), |_| View(0));
7361        let presenter = cx.presenters_and_platform_windows[&window_id].0.clone();
7362
7363        assert_eq!(
7364            presenter.borrow().rendered_views[&root_view.id()].name(),
7365            Some("render count: 0")
7366        );
7367
7368        let view = cx.add_view(&root_view, |cx| {
7369            cx.refresh_windows();
7370            View(0)
7371        });
7372
7373        assert_eq!(
7374            presenter.borrow().rendered_views[&root_view.id()].name(),
7375            Some("render count: 1")
7376        );
7377        assert_eq!(
7378            presenter.borrow().rendered_views[&view.id()].name(),
7379            Some("render count: 0")
7380        );
7381
7382        cx.update(|cx| cx.refresh_windows());
7383        assert_eq!(
7384            presenter.borrow().rendered_views[&root_view.id()].name(),
7385            Some("render count: 2")
7386        );
7387        assert_eq!(
7388            presenter.borrow().rendered_views[&view.id()].name(),
7389            Some("render count: 1")
7390        );
7391
7392        cx.update(|cx| {
7393            cx.refresh_windows();
7394            drop(view);
7395        });
7396        assert_eq!(
7397            presenter.borrow().rendered_views[&root_view.id()].name(),
7398            Some("render count: 3")
7399        );
7400        assert_eq!(presenter.borrow().rendered_views.len(), 1);
7401    }
7402
7403    #[crate::test(self)]
7404    async fn test_window_activation(cx: &mut TestAppContext) {
7405        struct View(&'static str);
7406
7407        impl super::Entity for View {
7408            type Event = ();
7409        }
7410
7411        impl super::View for View {
7412            fn ui_name() -> &'static str {
7413                "test view"
7414            }
7415
7416            fn render(&mut self, _: &mut RenderContext<Self>) -> ElementBox {
7417                Empty::new().boxed()
7418            }
7419        }
7420
7421        let events = Rc::new(RefCell::new(Vec::new()));
7422        let (window_1, _) = cx.add_window(|cx: &mut ViewContext<View>| {
7423            cx.observe_window_activation({
7424                let events = events.clone();
7425                move |this, active, _| events.borrow_mut().push((this.0, active))
7426            })
7427            .detach();
7428            View("window 1")
7429        });
7430        assert_eq!(mem::take(&mut *events.borrow_mut()), [("window 1", true)]);
7431
7432        let (window_2, _) = cx.add_window(|cx: &mut ViewContext<View>| {
7433            cx.observe_window_activation({
7434                let events = events.clone();
7435                move |this, active, _| events.borrow_mut().push((this.0, active))
7436            })
7437            .detach();
7438            View("window 2")
7439        });
7440        assert_eq!(
7441            mem::take(&mut *events.borrow_mut()),
7442            [("window 1", false), ("window 2", true)]
7443        );
7444
7445        let (window_3, _) = cx.add_window(|cx: &mut ViewContext<View>| {
7446            cx.observe_window_activation({
7447                let events = events.clone();
7448                move |this, active, _| events.borrow_mut().push((this.0, active))
7449            })
7450            .detach();
7451            View("window 3")
7452        });
7453        assert_eq!(
7454            mem::take(&mut *events.borrow_mut()),
7455            [("window 2", false), ("window 3", true)]
7456        );
7457
7458        cx.simulate_window_activation(Some(window_2));
7459        assert_eq!(
7460            mem::take(&mut *events.borrow_mut()),
7461            [("window 3", false), ("window 2", true)]
7462        );
7463
7464        cx.simulate_window_activation(Some(window_1));
7465        assert_eq!(
7466            mem::take(&mut *events.borrow_mut()),
7467            [("window 2", false), ("window 1", true)]
7468        );
7469
7470        cx.simulate_window_activation(Some(window_3));
7471        assert_eq!(
7472            mem::take(&mut *events.borrow_mut()),
7473            [("window 1", false), ("window 3", true)]
7474        );
7475
7476        cx.simulate_window_activation(Some(window_3));
7477        assert_eq!(mem::take(&mut *events.borrow_mut()), []);
7478    }
7479}