1pub mod action;
   2mod callback_collection;
   3mod menu;
   4pub(crate) mod ref_counts;
   5#[cfg(any(test, feature = "test-support"))]
   6pub mod test_app_context;
   7pub(crate) mod window;
   8mod window_input_handler;
   9
  10use std::{
  11    any::{type_name, Any, TypeId},
  12    cell::RefCell,
  13    fmt::{self, Debug},
  14    hash::{Hash, Hasher},
  15    marker::PhantomData,
  16    mem,
  17    ops::{Deref, DerefMut, Range},
  18    path::{Path, PathBuf},
  19    pin::Pin,
  20    rc::{self, Rc},
  21    sync::{Arc, Weak},
  22    time::Duration,
  23};
  24
  25use anyhow::{anyhow, Context, Result};
  26use parking_lot::Mutex;
  27use postage::oneshot;
  28use smallvec::SmallVec;
  29use smol::prelude::*;
  30use util::ResultExt;
  31use uuid::Uuid;
  32
  33pub use action::*;
  34use callback_collection::CallbackCollection;
  35use collections::{hash_map::Entry, BTreeMap, HashMap, HashSet, VecDeque};
  36pub use menu::*;
  37use platform::Event;
  38#[cfg(any(test, feature = "test-support"))]
  39use ref_counts::LeakDetector;
  40#[cfg(any(test, feature = "test-support"))]
  41pub use test_app_context::{ContextHandle, TestAppContext};
  42use window_input_handler::WindowInputHandler;
  43
  44use crate::{
  45    elements::{AnyElement, AnyRootElement, RootElement},
  46    executor::{self, Task},
  47    json,
  48    keymap_matcher::{self, Binding, KeymapContext, KeymapMatcher, Keystroke, MatchResult},
  49    platform::{
  50        self, FontSystem, KeyDownEvent, KeyUpEvent, ModifiersChangedEvent, MouseButton,
  51        PathPromptOptions, Platform, PromptLevel, WindowBounds, WindowOptions,
  52    },
  53    util::post_inc,
  54    window::{Window, WindowContext},
  55    AssetCache, AssetSource, ClipboardItem, FontCache, MouseRegionId,
  56};
  57
  58use self::ref_counts::RefCounts;
  59
  60pub trait Entity: 'static {
  61    type Event;
  62
  63    fn release(&mut self, _: &mut AppContext) {}
  64    fn app_will_quit(
  65        &mut self,
  66        _: &mut AppContext,
  67    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
  68        None
  69    }
  70}
  71
  72pub trait View: Entity + Sized {
  73    fn ui_name() -> &'static str;
  74    fn render(&mut self, cx: &mut ViewContext<'_, '_, Self>) -> AnyElement<Self>;
  75    fn focus_in(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  76    fn focus_out(&mut self, _: AnyViewHandle, _: &mut ViewContext<Self>) {}
  77    fn key_down(&mut self, _: &KeyDownEvent, _: &mut ViewContext<Self>) -> bool {
  78        false
  79    }
  80    fn key_up(&mut self, _: &KeyUpEvent, _: &mut ViewContext<Self>) -> bool {
  81        false
  82    }
  83    fn modifiers_changed(&mut self, _: &ModifiersChangedEvent, _: &mut ViewContext<Self>) -> bool {
  84        false
  85    }
  86
  87    fn update_keymap_context(&self, keymap: &mut keymap_matcher::KeymapContext, _: &AppContext) {
  88        Self::reset_to_default_keymap_context(keymap);
  89    }
  90
  91    fn reset_to_default_keymap_context(keymap: &mut keymap_matcher::KeymapContext) {
  92        keymap.clear();
  93        keymap.add_identifier(Self::ui_name());
  94    }
  95
  96    fn debug_json(&self, _: &AppContext) -> serde_json::Value {
  97        serde_json::Value::Null
  98    }
  99
 100    fn text_for_range(&self, _: Range<usize>, _: &AppContext) -> Option<String> {
 101        None
 102    }
 103    fn selected_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
 104        None
 105    }
 106    fn marked_text_range(&self, _: &AppContext) -> Option<Range<usize>> {
 107        None
 108    }
 109    fn unmark_text(&mut self, _: &mut ViewContext<Self>) {}
 110    fn replace_text_in_range(
 111        &mut self,
 112        _: Option<Range<usize>>,
 113        _: &str,
 114        _: &mut ViewContext<Self>,
 115    ) {
 116    }
 117    fn replace_and_mark_text_in_range(
 118        &mut self,
 119        _: Option<Range<usize>>,
 120        _: &str,
 121        _: Option<Range<usize>>,
 122        _: &mut ViewContext<Self>,
 123    ) {
 124    }
 125}
 126
 127pub trait BorrowAppContext {
 128    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T;
 129    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T;
 130}
 131
 132pub trait BorrowWindowContext {
 133    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T;
 134    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T;
 135}
 136
 137#[derive(Clone)]
 138pub struct App(Rc<RefCell<AppContext>>);
 139
 140impl App {
 141    pub fn new(asset_source: impl AssetSource) -> Result<Self> {
 142        let platform = platform::current::platform();
 143        let foreground = Rc::new(executor::Foreground::platform(platform.dispatcher())?);
 144        let foreground_platform = platform::current::foreground_platform(foreground.clone());
 145        let app = Self(Rc::new(RefCell::new(AppContext::new(
 146            foreground,
 147            Arc::new(executor::Background::new()),
 148            platform.clone(),
 149            foreground_platform.clone(),
 150            Arc::new(FontCache::new(platform.fonts())),
 151            Default::default(),
 152            asset_source,
 153        ))));
 154
 155        foreground_platform.on_quit(Box::new({
 156            let cx = app.0.clone();
 157            move || {
 158                cx.borrow_mut().quit();
 159            }
 160        }));
 161        setup_menu_handlers(foreground_platform.as_ref(), &app);
 162
 163        app.0.borrow_mut().weak_self = Some(Rc::downgrade(&app.0));
 164        Ok(app)
 165    }
 166
 167    pub fn background(&self) -> Arc<executor::Background> {
 168        self.0.borrow().background().clone()
 169    }
 170
 171    pub fn on_become_active<F>(self, mut callback: F) -> Self
 172    where
 173        F: 'static + FnMut(&mut AppContext),
 174    {
 175        let cx = self.0.clone();
 176        self.0
 177            .borrow_mut()
 178            .foreground_platform
 179            .on_become_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 180        self
 181    }
 182
 183    pub fn on_resign_active<F>(self, mut callback: F) -> Self
 184    where
 185        F: 'static + FnMut(&mut AppContext),
 186    {
 187        let cx = self.0.clone();
 188        self.0
 189            .borrow_mut()
 190            .foreground_platform
 191            .on_resign_active(Box::new(move || callback(&mut *cx.borrow_mut())));
 192        self
 193    }
 194
 195    pub fn on_quit<F>(&mut self, mut callback: F) -> &mut Self
 196    where
 197        F: 'static + FnMut(&mut AppContext),
 198    {
 199        let cx = self.0.clone();
 200        self.0
 201            .borrow_mut()
 202            .foreground_platform
 203            .on_quit(Box::new(move || callback(&mut *cx.borrow_mut())));
 204        self
 205    }
 206
 207    /// Handle the application being re-activated when no windows are open.
 208    pub fn on_reopen<F>(&mut self, mut callback: F) -> &mut Self
 209    where
 210        F: 'static + FnMut(&mut AppContext),
 211    {
 212        let cx = self.0.clone();
 213        self.0
 214            .borrow_mut()
 215            .foreground_platform
 216            .on_reopen(Box::new(move || callback(&mut *cx.borrow_mut())));
 217        self
 218    }
 219
 220    pub fn on_event<F>(&mut self, mut callback: F) -> &mut Self
 221    where
 222        F: 'static + FnMut(Event, &mut AppContext) -> bool,
 223    {
 224        let cx = self.0.clone();
 225        self.0
 226            .borrow_mut()
 227            .foreground_platform
 228            .on_event(Box::new(move |event| {
 229                callback(event, &mut *cx.borrow_mut())
 230            }));
 231        self
 232    }
 233
 234    pub fn on_open_urls<F>(&mut self, mut callback: F) -> &mut Self
 235    where
 236        F: 'static + FnMut(Vec<String>, &mut AppContext),
 237    {
 238        let cx = self.0.clone();
 239        self.0
 240            .borrow_mut()
 241            .foreground_platform
 242            .on_open_urls(Box::new(move |urls| callback(urls, &mut *cx.borrow_mut())));
 243        self
 244    }
 245
 246    pub fn run<F>(self, on_finish_launching: F)
 247    where
 248        F: 'static + FnOnce(&mut AppContext),
 249    {
 250        let platform = self.0.borrow().foreground_platform.clone();
 251        platform.run(Box::new(move || {
 252            let mut cx = self.0.borrow_mut();
 253            let cx = &mut *cx;
 254            crate::views::init(cx);
 255            on_finish_launching(cx);
 256        }))
 257    }
 258
 259    pub fn platform(&self) -> Arc<dyn Platform> {
 260        self.0.borrow().platform.clone()
 261    }
 262
 263    pub fn font_cache(&self) -> Arc<FontCache> {
 264        self.0.borrow().font_cache.clone()
 265    }
 266
 267    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, callback: F) -> T {
 268        let mut state = self.0.borrow_mut();
 269        let result = state.update(callback);
 270        state.pending_notifications.clear();
 271        result
 272    }
 273
 274    fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 275        &mut self,
 276        window_id: usize,
 277        callback: F,
 278    ) -> Option<T> {
 279        let mut state = self.0.borrow_mut();
 280        let result = state.update_window(window_id, callback);
 281        state.pending_notifications.clear();
 282        result
 283    }
 284}
 285
 286#[derive(Clone)]
 287pub struct AsyncAppContext(Rc<RefCell<AppContext>>);
 288
 289impl AsyncAppContext {
 290    pub fn spawn<F, Fut, T>(&self, f: F) -> Task<T>
 291    where
 292        F: FnOnce(AsyncAppContext) -> Fut,
 293        Fut: 'static + Future<Output = T>,
 294        T: 'static,
 295    {
 296        self.0.borrow().foreground.spawn(f(self.clone()))
 297    }
 298
 299    pub fn read<T, F: FnOnce(&AppContext) -> T>(&self, callback: F) -> T {
 300        callback(&*self.0.borrow())
 301    }
 302
 303    pub fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, callback: F) -> T {
 304        self.0.borrow_mut().update(callback)
 305    }
 306
 307    pub fn read_window<T, F: FnOnce(&WindowContext) -> T>(
 308        &self,
 309        window_id: usize,
 310        callback: F,
 311    ) -> Option<T> {
 312        self.0.borrow_mut().read_window(window_id, callback)
 313    }
 314
 315    pub fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 316        &mut self,
 317        window_id: usize,
 318        callback: F,
 319    ) -> Option<T> {
 320        self.0.borrow_mut().update_window(window_id, callback)
 321    }
 322
 323    pub fn debug_elements(&self, window_id: usize) -> Option<json::Value> {
 324        self.0.borrow().read_window(window_id, |cx| {
 325            let root_view = cx.window.root_view();
 326            let root_element = cx.window.rendered_views.get(&root_view.id())?;
 327            root_element.debug(cx).log_err()
 328        })?
 329    }
 330
 331    pub fn dispatch_action(
 332        &mut self,
 333        window_id: usize,
 334        view_id: usize,
 335        action: &dyn Action,
 336    ) -> Result<()> {
 337        self.0
 338            .borrow_mut()
 339            .update_window(window_id, |window| {
 340                window.dispatch_action(Some(view_id), action);
 341            })
 342            .ok_or_else(|| anyhow!("window not found"))
 343    }
 344
 345    pub fn available_actions(
 346        &self,
 347        window_id: usize,
 348        view_id: usize,
 349    ) -> Vec<(&'static str, Box<dyn Action>, SmallVec<[Binding; 1]>)> {
 350        self.read_window(window_id, |cx| cx.available_actions(view_id))
 351            .unwrap_or_default()
 352    }
 353
 354    pub fn has_window(&self, window_id: usize) -> bool {
 355        self.read(|cx| cx.windows.contains_key(&window_id))
 356    }
 357
 358    pub fn window_is_active(&self, window_id: usize) -> bool {
 359        self.read(|cx| cx.windows.get(&window_id).map_or(false, |w| w.is_active))
 360    }
 361
 362    pub fn root_view(&self, window_id: usize) -> Option<AnyViewHandle> {
 363        self.read(|cx| cx.windows.get(&window_id).map(|w| w.root_view().clone()))
 364    }
 365
 366    pub fn window_ids(&self) -> Vec<usize> {
 367        self.read(|cx| cx.windows.keys().copied().collect())
 368    }
 369
 370    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
 371    where
 372        T: Entity,
 373        F: FnOnce(&mut ModelContext<T>) -> T,
 374    {
 375        self.update(|cx| cx.add_model(build_model))
 376    }
 377
 378    pub fn add_window<T, F>(
 379        &mut self,
 380        window_options: WindowOptions,
 381        build_root_view: F,
 382    ) -> (usize, ViewHandle<T>)
 383    where
 384        T: View,
 385        F: FnOnce(&mut ViewContext<T>) -> T,
 386    {
 387        self.update(|cx| cx.add_window(window_options, build_root_view))
 388    }
 389
 390    pub fn remove_window(&mut self, window_id: usize) {
 391        self.update_window(window_id, |cx| cx.remove_window());
 392    }
 393
 394    pub fn activate_window(&mut self, window_id: usize) {
 395        self.update_window(window_id, |cx| cx.activate_window());
 396    }
 397
 398    // TODO: Can we eliminate this method and move it to WindowContext then call it with update_window?s
 399    pub fn prompt(
 400        &mut self,
 401        window_id: usize,
 402        level: PromptLevel,
 403        msg: &str,
 404        answers: &[&str],
 405    ) -> Option<oneshot::Receiver<usize>> {
 406        self.update_window(window_id, |cx| cx.prompt(level, msg, answers))
 407    }
 408
 409    pub fn platform(&self) -> Arc<dyn Platform> {
 410        self.0.borrow().platform().clone()
 411    }
 412
 413    pub fn foreground(&self) -> Rc<executor::Foreground> {
 414        self.0.borrow().foreground.clone()
 415    }
 416
 417    pub fn background(&self) -> Arc<executor::Background> {
 418        self.0.borrow().background.clone()
 419    }
 420}
 421
 422impl BorrowAppContext for AsyncAppContext {
 423    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
 424        self.0.borrow().read_with(f)
 425    }
 426
 427    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
 428        self.0.borrow_mut().update(f)
 429    }
 430}
 431
 432type ActionCallback = dyn FnMut(&mut dyn AnyView, &dyn Action, &mut WindowContext, usize);
 433type GlobalActionCallback = dyn FnMut(&dyn Action, &mut AppContext);
 434
 435type SubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool>;
 436type GlobalSubscriptionCallback = Box<dyn FnMut(&dyn Any, &mut AppContext)>;
 437type ObservationCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 438type GlobalObservationCallback = Box<dyn FnMut(&mut AppContext)>;
 439type FocusObservationCallback = Box<dyn FnMut(bool, &mut WindowContext) -> bool>;
 440type ReleaseObservationCallback = Box<dyn FnMut(&dyn Any, &mut AppContext)>;
 441type ActionObservationCallback = Box<dyn FnMut(TypeId, &mut AppContext)>;
 442type WindowActivationCallback = Box<dyn FnMut(bool, &mut WindowContext) -> bool>;
 443type WindowFullscreenCallback = Box<dyn FnMut(bool, &mut WindowContext) -> bool>;
 444type WindowBoundsCallback = Box<dyn FnMut(WindowBounds, Uuid, &mut WindowContext) -> bool>;
 445type KeystrokeCallback =
 446    Box<dyn FnMut(&Keystroke, &MatchResult, Option<&Box<dyn Action>>, &mut WindowContext) -> bool>;
 447type ActiveLabeledTasksCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 448type DeserializeActionCallback = fn(json: &str) -> anyhow::Result<Box<dyn Action>>;
 449type WindowShouldCloseSubscriptionCallback = Box<dyn FnMut(&mut AppContext) -> bool>;
 450
 451pub struct AppContext {
 452    models: HashMap<usize, Box<dyn AnyModel>>,
 453    views: HashMap<(usize, usize), Box<dyn AnyView>>,
 454    views_metadata: HashMap<(usize, usize), ViewMetadata>,
 455    windows: HashMap<usize, Window>,
 456    globals: HashMap<TypeId, Box<dyn Any>>,
 457    element_states: HashMap<ElementStateId, Box<dyn Any>>,
 458    background: Arc<executor::Background>,
 459    ref_counts: Arc<Mutex<RefCounts>>,
 460
 461    weak_self: Option<rc::Weak<RefCell<Self>>>,
 462    platform: Arc<dyn Platform>,
 463    foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 464    pub asset_cache: Arc<AssetCache>,
 465    font_system: Arc<dyn FontSystem>,
 466    pub font_cache: Arc<FontCache>,
 467    action_deserializers: HashMap<&'static str, (TypeId, DeserializeActionCallback)>,
 468    capture_actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 469    // Entity Types -> { Action Types -> Action Handlers }
 470    actions: HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>>,
 471    // Action Types -> Action Handlers
 472    global_actions: HashMap<TypeId, Box<GlobalActionCallback>>,
 473    keystroke_matcher: KeymapMatcher,
 474    next_entity_id: usize,
 475    next_window_id: usize,
 476    next_subscription_id: usize,
 477    frame_count: usize,
 478
 479    subscriptions: CallbackCollection<usize, SubscriptionCallback>,
 480    global_subscriptions: CallbackCollection<TypeId, GlobalSubscriptionCallback>,
 481    observations: CallbackCollection<usize, ObservationCallback>,
 482    global_observations: CallbackCollection<TypeId, GlobalObservationCallback>,
 483    focus_observations: CallbackCollection<usize, FocusObservationCallback>,
 484    release_observations: CallbackCollection<usize, ReleaseObservationCallback>,
 485    action_dispatch_observations: CallbackCollection<(), ActionObservationCallback>,
 486    window_activation_observations: CallbackCollection<usize, WindowActivationCallback>,
 487    window_fullscreen_observations: CallbackCollection<usize, WindowFullscreenCallback>,
 488    window_bounds_observations: CallbackCollection<usize, WindowBoundsCallback>,
 489    keystroke_observations: CallbackCollection<usize, KeystrokeCallback>,
 490    active_labeled_task_observations: CallbackCollection<(), ActiveLabeledTasksCallback>,
 491
 492    foreground: Rc<executor::Foreground>,
 493    pending_effects: VecDeque<Effect>,
 494    pending_notifications: HashSet<usize>,
 495    pending_global_notifications: HashSet<TypeId>,
 496    pending_flushes: usize,
 497    flushing_effects: bool,
 498    halt_action_dispatch: bool,
 499    next_labeled_task_id: usize,
 500    active_labeled_tasks: BTreeMap<usize, &'static str>,
 501}
 502
 503impl AppContext {
 504    fn new(
 505        foreground: Rc<executor::Foreground>,
 506        background: Arc<executor::Background>,
 507        platform: Arc<dyn platform::Platform>,
 508        foreground_platform: Rc<dyn platform::ForegroundPlatform>,
 509        font_cache: Arc<FontCache>,
 510        ref_counts: RefCounts,
 511        asset_source: impl AssetSource,
 512    ) -> Self {
 513        Self {
 514            models: Default::default(),
 515            views: Default::default(),
 516            views_metadata: Default::default(),
 517            windows: Default::default(),
 518            globals: Default::default(),
 519            element_states: Default::default(),
 520            ref_counts: Arc::new(Mutex::new(ref_counts)),
 521            background,
 522
 523            weak_self: None,
 524            font_system: platform.fonts(),
 525            platform,
 526            foreground_platform,
 527            font_cache,
 528            asset_cache: Arc::new(AssetCache::new(asset_source)),
 529            action_deserializers: Default::default(),
 530            capture_actions: Default::default(),
 531            actions: Default::default(),
 532            global_actions: Default::default(),
 533            keystroke_matcher: KeymapMatcher::default(),
 534            next_entity_id: 0,
 535            next_window_id: 0,
 536            next_subscription_id: 0,
 537            frame_count: 0,
 538            subscriptions: Default::default(),
 539            global_subscriptions: Default::default(),
 540            observations: Default::default(),
 541            focus_observations: Default::default(),
 542            release_observations: Default::default(),
 543            global_observations: Default::default(),
 544            window_activation_observations: Default::default(),
 545            window_fullscreen_observations: Default::default(),
 546            window_bounds_observations: Default::default(),
 547            keystroke_observations: Default::default(),
 548            action_dispatch_observations: Default::default(),
 549            active_labeled_task_observations: Default::default(),
 550            foreground,
 551            pending_effects: VecDeque::new(),
 552            pending_notifications: Default::default(),
 553            pending_global_notifications: Default::default(),
 554            pending_flushes: 0,
 555            flushing_effects: false,
 556            halt_action_dispatch: false,
 557            next_labeled_task_id: 0,
 558            active_labeled_tasks: Default::default(),
 559        }
 560    }
 561
 562    pub fn background(&self) -> &Arc<executor::Background> {
 563        &self.background
 564    }
 565
 566    pub fn font_cache(&self) -> &Arc<FontCache> {
 567        &self.font_cache
 568    }
 569
 570    pub fn platform(&self) -> &Arc<dyn Platform> {
 571        &self.platform
 572    }
 573
 574    pub fn has_global<T: 'static>(&self) -> bool {
 575        self.globals.contains_key(&TypeId::of::<T>())
 576    }
 577
 578    pub fn global<T: 'static>(&self) -> &T {
 579        if let Some(global) = self.globals.get(&TypeId::of::<T>()) {
 580            global.downcast_ref().unwrap()
 581        } else {
 582            panic!("no global has been added for {}", type_name::<T>());
 583        }
 584    }
 585
 586    pub fn upgrade(&self) -> App {
 587        App(self.weak_self.as_ref().unwrap().upgrade().unwrap())
 588    }
 589
 590    fn quit(&mut self) {
 591        let mut futures = Vec::new();
 592
 593        self.update(|cx| {
 594            for model_id in cx.models.keys().copied().collect::<Vec<_>>() {
 595                let mut model = cx.models.remove(&model_id).unwrap();
 596                futures.extend(model.app_will_quit(cx));
 597                cx.models.insert(model_id, model);
 598            }
 599
 600            for view_id in cx.views.keys().copied().collect::<Vec<_>>() {
 601                let mut view = cx.views.remove(&view_id).unwrap();
 602                futures.extend(view.app_will_quit(cx));
 603                cx.views.insert(view_id, view);
 604            }
 605        });
 606
 607        self.windows.clear();
 608        self.flush_effects();
 609
 610        let futures = futures::future::join_all(futures);
 611        if self
 612            .background
 613            .block_with_timeout(Duration::from_millis(100), futures)
 614            .is_err()
 615        {
 616            log::error!("timed out waiting on app_will_quit");
 617        }
 618    }
 619
 620    pub fn foreground(&self) -> &Rc<executor::Foreground> {
 621        &self.foreground
 622    }
 623
 624    pub fn deserialize_action(
 625        &self,
 626        name: &str,
 627        argument: Option<&str>,
 628    ) -> Result<Box<dyn Action>> {
 629        let callback = self
 630            .action_deserializers
 631            .get(name)
 632            .ok_or_else(|| anyhow!("unknown action {}", name))?
 633            .1;
 634        callback(argument.unwrap_or("{}"))
 635            .with_context(|| format!("invalid data for action {}", name))
 636    }
 637
 638    pub fn add_action<A, V, F, R>(&mut self, handler: F)
 639    where
 640        A: Action,
 641        V: View,
 642        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> R,
 643    {
 644        self.add_action_internal(handler, false)
 645    }
 646
 647    pub fn capture_action<A, V, F>(&mut self, handler: F)
 648    where
 649        A: Action,
 650        V: View,
 651        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>),
 652    {
 653        self.add_action_internal(handler, true)
 654    }
 655
 656    fn add_action_internal<A, V, F, R>(&mut self, mut handler: F, capture: bool)
 657    where
 658        A: Action,
 659        V: View,
 660        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> R,
 661    {
 662        let handler = Box::new(
 663            move |view: &mut dyn AnyView,
 664                  action: &dyn Action,
 665                  cx: &mut WindowContext,
 666                  view_id: usize| {
 667                let action = action.as_any().downcast_ref().unwrap();
 668                let mut cx = ViewContext::mutable(cx, view_id);
 669                handler(
 670                    view.as_any_mut()
 671                        .downcast_mut()
 672                        .expect("downcast is type safe"),
 673                    action,
 674                    &mut cx,
 675                );
 676            },
 677        );
 678
 679        self.action_deserializers
 680            .entry(A::qualified_name())
 681            .or_insert((TypeId::of::<A>(), A::from_json_str));
 682
 683        let actions = if capture {
 684            &mut self.capture_actions
 685        } else {
 686            &mut self.actions
 687        };
 688
 689        actions
 690            .entry(TypeId::of::<V>())
 691            .or_default()
 692            .entry(TypeId::of::<A>())
 693            .or_default()
 694            .push(handler);
 695    }
 696
 697    pub fn add_async_action<A, V, F>(&mut self, mut handler: F)
 698    where
 699        A: Action,
 700        V: View,
 701        F: 'static + FnMut(&mut V, &A, &mut ViewContext<V>) -> Option<Task<Result<()>>>,
 702    {
 703        self.add_action(move |view, action, cx| {
 704            if let Some(task) = handler(view, action, cx) {
 705                task.detach_and_log_err(cx);
 706            }
 707        })
 708    }
 709
 710    pub fn add_global_action<A, F>(&mut self, mut handler: F)
 711    where
 712        A: Action,
 713        F: 'static + FnMut(&A, &mut AppContext),
 714    {
 715        let handler = Box::new(move |action: &dyn Action, cx: &mut AppContext| {
 716            let action = action.as_any().downcast_ref().unwrap();
 717            handler(action, cx);
 718        });
 719
 720        self.action_deserializers
 721            .entry(A::qualified_name())
 722            .or_insert((TypeId::of::<A>(), A::from_json_str));
 723
 724        if self
 725            .global_actions
 726            .insert(TypeId::of::<A>(), handler)
 727            .is_some()
 728        {
 729            panic!(
 730                "registered multiple global handlers for {}",
 731                type_name::<A>()
 732            );
 733        }
 734    }
 735
 736    pub fn view_ui_name(&self, window_id: usize, view_id: usize) -> Option<&'static str> {
 737        Some(self.views.get(&(window_id, view_id))?.ui_name())
 738    }
 739
 740    pub fn view_type_id(&self, window_id: usize, view_id: usize) -> Option<TypeId> {
 741        self.views_metadata
 742            .get(&(window_id, view_id))
 743            .map(|metadata| metadata.type_id)
 744    }
 745
 746    pub fn active_labeled_tasks<'a>(
 747        &'a self,
 748    ) -> impl DoubleEndedIterator<Item = &'static str> + 'a {
 749        self.active_labeled_tasks.values().cloned()
 750    }
 751
 752    pub(crate) fn start_frame(&mut self) {
 753        self.frame_count += 1;
 754    }
 755
 756    pub fn update<T, F: FnOnce(&mut Self) -> T>(&mut self, callback: F) -> T {
 757        self.pending_flushes += 1;
 758        let result = callback(self);
 759        self.flush_effects();
 760        result
 761    }
 762
 763    pub fn read_window<T, F: FnOnce(&WindowContext) -> T>(
 764        &self,
 765        window_id: usize,
 766        callback: F,
 767    ) -> Option<T> {
 768        let window = self.windows.get(&window_id)?;
 769        let window_context = WindowContext::immutable(self, &window, window_id);
 770        Some(callback(&window_context))
 771    }
 772
 773    pub fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 774        &mut self,
 775        window_id: usize,
 776        callback: F,
 777    ) -> Option<T> {
 778        self.update(|app_context| {
 779            let mut window = app_context.windows.remove(&window_id)?;
 780            let mut window_context = WindowContext::mutable(app_context, &mut window, window_id);
 781            let result = callback(&mut window_context);
 782            if !window_context.removed {
 783                app_context.windows.insert(window_id, window);
 784            }
 785            Some(result)
 786        })
 787    }
 788
 789    pub fn update_active_window<T, F: FnOnce(&mut WindowContext) -> T>(
 790        &mut self,
 791        callback: F,
 792    ) -> Option<T> {
 793        self.platform
 794            .main_window_id()
 795            .and_then(|id| self.update_window(id, callback))
 796    }
 797
 798    pub fn prompt_for_paths(
 799        &self,
 800        options: PathPromptOptions,
 801    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
 802        self.foreground_platform.prompt_for_paths(options)
 803    }
 804
 805    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
 806        self.foreground_platform.prompt_for_new_path(directory)
 807    }
 808
 809    pub fn reveal_path(&self, path: &Path) {
 810        self.foreground_platform.reveal_path(path)
 811    }
 812
 813    pub fn emit_global<E: Any>(&mut self, payload: E) {
 814        self.pending_effects.push_back(Effect::GlobalEvent {
 815            payload: Box::new(payload),
 816        });
 817    }
 818
 819    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 820    where
 821        E: Entity,
 822        E::Event: 'static,
 823        H: Handle<E>,
 824        F: 'static + FnMut(H, &E::Event, &mut Self),
 825    {
 826        self.subscribe_internal(handle, move |handle, event, cx| {
 827            callback(handle, event, cx);
 828            true
 829        })
 830    }
 831
 832    pub fn subscribe_global<E, F>(&mut self, mut callback: F) -> Subscription
 833    where
 834        E: Any,
 835        F: 'static + FnMut(&E, &mut Self),
 836    {
 837        let subscription_id = post_inc(&mut self.next_subscription_id);
 838        let type_id = TypeId::of::<E>();
 839        self.pending_effects.push_back(Effect::GlobalSubscription {
 840            type_id,
 841            subscription_id,
 842            callback: Box::new(move |payload, cx| {
 843                let payload = payload.downcast_ref().expect("downcast is type safe");
 844                callback(payload, cx)
 845            }),
 846        });
 847        Subscription::GlobalSubscription(
 848            self.global_subscriptions
 849                .subscribe(type_id, subscription_id),
 850        )
 851    }
 852
 853    pub fn observe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 854    where
 855        E: Entity,
 856        E::Event: 'static,
 857        H: Handle<E>,
 858        F: 'static + FnMut(H, &mut Self),
 859    {
 860        self.observe_internal(handle, move |handle, cx| {
 861            callback(handle, cx);
 862            true
 863        })
 864    }
 865
 866    fn subscribe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 867    where
 868        E: Entity,
 869        E::Event: 'static,
 870        H: Handle<E>,
 871        F: 'static + FnMut(H, &E::Event, &mut Self) -> bool,
 872    {
 873        let subscription_id = post_inc(&mut self.next_subscription_id);
 874        let emitter = handle.downgrade();
 875        self.pending_effects.push_back(Effect::Subscription {
 876            entity_id: handle.id(),
 877            subscription_id,
 878            callback: Box::new(move |payload, cx| {
 879                if let Some(emitter) = H::upgrade_from(&emitter, cx) {
 880                    let payload = payload.downcast_ref().expect("downcast is type safe");
 881                    callback(emitter, payload, cx)
 882                } else {
 883                    false
 884                }
 885            }),
 886        });
 887        Subscription::Subscription(self.subscriptions.subscribe(handle.id(), subscription_id))
 888    }
 889
 890    fn observe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 891    where
 892        E: Entity,
 893        E::Event: 'static,
 894        H: Handle<E>,
 895        F: 'static + FnMut(H, &mut Self) -> bool,
 896    {
 897        let subscription_id = post_inc(&mut self.next_subscription_id);
 898        let observed = handle.downgrade();
 899        let entity_id = handle.id();
 900        self.pending_effects.push_back(Effect::Observation {
 901            entity_id,
 902            subscription_id,
 903            callback: Box::new(move |cx| {
 904                if let Some(observed) = H::upgrade_from(&observed, cx) {
 905                    callback(observed, cx)
 906                } else {
 907                    false
 908                }
 909            }),
 910        });
 911        Subscription::Observation(self.observations.subscribe(entity_id, subscription_id))
 912    }
 913
 914    fn observe_focus<F, V>(&mut self, handle: &ViewHandle<V>, mut callback: F) -> Subscription
 915    where
 916        F: 'static + FnMut(ViewHandle<V>, bool, &mut WindowContext) -> bool,
 917        V: View,
 918    {
 919        let subscription_id = post_inc(&mut self.next_subscription_id);
 920        let observed = handle.downgrade();
 921        let view_id = handle.id();
 922
 923        self.pending_effects.push_back(Effect::FocusObservation {
 924            view_id,
 925            subscription_id,
 926            callback: Box::new(move |focused, cx| {
 927                if let Some(observed) = observed.upgrade(cx) {
 928                    callback(observed, focused, cx)
 929                } else {
 930                    false
 931                }
 932            }),
 933        });
 934        Subscription::FocusObservation(self.focus_observations.subscribe(view_id, subscription_id))
 935    }
 936
 937    pub fn observe_global<G, F>(&mut self, mut observe: F) -> Subscription
 938    where
 939        G: Any,
 940        F: 'static + FnMut(&mut AppContext),
 941    {
 942        let type_id = TypeId::of::<G>();
 943        let id = post_inc(&mut self.next_subscription_id);
 944
 945        self.global_observations.add_callback(
 946            type_id,
 947            id,
 948            Box::new(move |cx: &mut AppContext| observe(cx)),
 949        );
 950        Subscription::GlobalObservation(self.global_observations.subscribe(type_id, id))
 951    }
 952
 953    pub fn observe_default_global<G, F>(&mut self, observe: F) -> Subscription
 954    where
 955        G: Any + Default,
 956        F: 'static + FnMut(&mut AppContext),
 957    {
 958        if !self.has_global::<G>() {
 959            self.set_global(G::default());
 960        }
 961        self.observe_global::<G, F>(observe)
 962    }
 963
 964    pub fn observe_release<E, H, F>(&mut self, handle: &H, callback: F) -> Subscription
 965    where
 966        E: Entity,
 967        E::Event: 'static,
 968        H: Handle<E>,
 969        F: 'static + FnOnce(&E, &mut Self),
 970    {
 971        let id = post_inc(&mut self.next_subscription_id);
 972        let mut callback = Some(callback);
 973        self.release_observations.add_callback(
 974            handle.id(),
 975            id,
 976            Box::new(move |released, cx| {
 977                let released = released.downcast_ref().unwrap();
 978                if let Some(callback) = callback.take() {
 979                    callback(released, cx)
 980                }
 981            }),
 982        );
 983        Subscription::ReleaseObservation(self.release_observations.subscribe(handle.id(), id))
 984    }
 985
 986    pub fn observe_actions<F>(&mut self, callback: F) -> Subscription
 987    where
 988        F: 'static + FnMut(TypeId, &mut AppContext),
 989    {
 990        let subscription_id = post_inc(&mut self.next_subscription_id);
 991        self.action_dispatch_observations
 992            .add_callback((), subscription_id, Box::new(callback));
 993        Subscription::ActionObservation(
 994            self.action_dispatch_observations
 995                .subscribe((), subscription_id),
 996        )
 997    }
 998
 999    fn observe_active_labeled_tasks<F>(&mut self, callback: F) -> Subscription
1000    where
1001        F: 'static + FnMut(&mut AppContext) -> bool,
1002    {
1003        let subscription_id = post_inc(&mut self.next_subscription_id);
1004        self.active_labeled_task_observations
1005            .add_callback((), subscription_id, Box::new(callback));
1006        Subscription::ActiveLabeledTasksObservation(
1007            self.active_labeled_task_observations
1008                .subscribe((), subscription_id),
1009        )
1010    }
1011
1012    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut AppContext)) {
1013        self.pending_effects.push_back(Effect::Deferred {
1014            callback: Box::new(callback),
1015            after_window_update: false,
1016        })
1017    }
1018
1019    pub fn after_window_update(&mut self, callback: impl 'static + FnOnce(&mut AppContext)) {
1020        self.pending_effects.push_back(Effect::Deferred {
1021            callback: Box::new(callback),
1022            after_window_update: true,
1023        })
1024    }
1025
1026    fn notify_model(&mut self, model_id: usize) {
1027        if self.pending_notifications.insert(model_id) {
1028            self.pending_effects
1029                .push_back(Effect::ModelNotification { model_id });
1030        }
1031    }
1032
1033    fn notify_view(&mut self, window_id: usize, view_id: usize) {
1034        if self.pending_notifications.insert(view_id) {
1035            self.pending_effects
1036                .push_back(Effect::ViewNotification { window_id, view_id });
1037        }
1038    }
1039
1040    fn notify_global(&mut self, type_id: TypeId) {
1041        if self.pending_global_notifications.insert(type_id) {
1042            self.pending_effects
1043                .push_back(Effect::GlobalNotification { type_id });
1044        }
1045    }
1046
1047    pub fn all_action_names<'a>(&'a self) -> impl Iterator<Item = &'static str> + 'a {
1048        self.action_deserializers.keys().copied()
1049    }
1050
1051    pub fn is_action_available(&self, action: &dyn Action) -> bool {
1052        let mut available_in_window = false;
1053        let action_type = action.as_any().type_id();
1054        if let Some(window_id) = self.platform.main_window_id() {
1055            available_in_window = self
1056                .read_window(window_id, |cx| {
1057                    if let Some(focused_view_id) = cx.focused_view_id() {
1058                        for view_id in cx.ancestors(focused_view_id) {
1059                            if let Some(view_metadata) =
1060                                cx.views_metadata.get(&(window_id, view_id))
1061                            {
1062                                if let Some(actions) = cx.actions.get(&view_metadata.type_id) {
1063                                    if actions.contains_key(&action_type) {
1064                                        return true;
1065                                    }
1066                                }
1067                            }
1068                        }
1069                    }
1070                    false
1071                })
1072                .unwrap_or(false);
1073        }
1074        available_in_window || self.global_actions.contains_key(&action_type)
1075    }
1076
1077    fn actions_mut(
1078        &mut self,
1079        capture_phase: bool,
1080    ) -> &mut HashMap<TypeId, HashMap<TypeId, Vec<Box<ActionCallback>>>> {
1081        if capture_phase {
1082            &mut self.capture_actions
1083        } else {
1084            &mut self.actions
1085        }
1086    }
1087
1088    fn dispatch_global_action_any(&mut self, action: &dyn Action) -> bool {
1089        self.update(|this| {
1090            if let Some((name, mut handler)) = this.global_actions.remove_entry(&action.id()) {
1091                handler(action, this);
1092                this.global_actions.insert(name, handler);
1093                true
1094            } else {
1095                false
1096            }
1097        })
1098    }
1099
1100    pub fn add_bindings<T: IntoIterator<Item = Binding>>(&mut self, bindings: T) {
1101        self.keystroke_matcher.add_bindings(bindings);
1102    }
1103
1104    pub fn clear_bindings(&mut self) {
1105        self.keystroke_matcher.clear_bindings();
1106    }
1107
1108    pub fn default_global<T: 'static + Default>(&mut self) -> &T {
1109        let type_id = TypeId::of::<T>();
1110        self.update(|this| {
1111            if let Entry::Vacant(entry) = this.globals.entry(type_id) {
1112                entry.insert(Box::new(T::default()));
1113                this.notify_global(type_id);
1114            }
1115        });
1116        self.globals.get(&type_id).unwrap().downcast_ref().unwrap()
1117    }
1118
1119    pub fn set_global<T: 'static>(&mut self, state: T) {
1120        self.update(|this| {
1121            let type_id = TypeId::of::<T>();
1122            this.globals.insert(type_id, Box::new(state));
1123            this.notify_global(type_id);
1124        });
1125    }
1126
1127    pub fn update_default_global<T, F, U>(&mut self, update: F) -> U
1128    where
1129        T: 'static + Default,
1130        F: FnOnce(&mut T, &mut AppContext) -> U,
1131    {
1132        self.update(|mut this| {
1133            Self::update_default_global_internal(&mut this, |global, cx| update(global, cx))
1134        })
1135    }
1136
1137    fn update_default_global_internal<C, T, F, U>(this: &mut C, update: F) -> U
1138    where
1139        C: DerefMut<Target = AppContext>,
1140        T: 'static + Default,
1141        F: FnOnce(&mut T, &mut C) -> U,
1142    {
1143        let type_id = TypeId::of::<T>();
1144        let mut state = this
1145            .globals
1146            .remove(&type_id)
1147            .unwrap_or_else(|| Box::new(T::default()));
1148        let result = update(state.downcast_mut().unwrap(), this);
1149        this.globals.insert(type_id, state);
1150        this.notify_global(type_id);
1151        result
1152    }
1153
1154    pub fn update_global<T, F, U>(&mut self, update: F) -> U
1155    where
1156        T: 'static,
1157        F: FnOnce(&mut T, &mut AppContext) -> U,
1158    {
1159        self.update(|mut this| {
1160            Self::update_global_internal(&mut this, |global, cx| update(global, cx))
1161        })
1162    }
1163
1164    fn update_global_internal<C, T, F, U>(this: &mut C, update: F) -> U
1165    where
1166        C: DerefMut<Target = AppContext>,
1167        T: 'static,
1168        F: FnOnce(&mut T, &mut C) -> U,
1169    {
1170        let type_id = TypeId::of::<T>();
1171        if let Some(mut state) = this.globals.remove(&type_id) {
1172            let result = update(state.downcast_mut().unwrap(), this);
1173            this.globals.insert(type_id, state);
1174            this.notify_global(type_id);
1175            result
1176        } else {
1177            panic!("No global added for {}", std::any::type_name::<T>());
1178        }
1179    }
1180
1181    pub fn clear_globals(&mut self) {
1182        self.globals.clear();
1183    }
1184
1185    pub fn add_model<T, F>(&mut self, build_model: F) -> ModelHandle<T>
1186    where
1187        T: Entity,
1188        F: FnOnce(&mut ModelContext<T>) -> T,
1189    {
1190        self.update(|this| {
1191            let model_id = post_inc(&mut this.next_entity_id);
1192            let handle = ModelHandle::new(model_id, &this.ref_counts);
1193            let mut cx = ModelContext::new(this, model_id);
1194            let model = build_model(&mut cx);
1195            this.models.insert(model_id, Box::new(model));
1196            handle
1197        })
1198    }
1199
1200    pub fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
1201        if let Some(model) = self.models.get(&handle.model_id) {
1202            model
1203                .as_any()
1204                .downcast_ref()
1205                .expect("downcast is type safe")
1206        } else {
1207            panic!("circular model reference");
1208        }
1209    }
1210
1211    fn update_model<T: Entity, V>(
1212        &mut self,
1213        handle: &ModelHandle<T>,
1214        update: &mut dyn FnMut(&mut T, &mut ModelContext<T>) -> V,
1215    ) -> V {
1216        if let Some(mut model) = self.models.remove(&handle.model_id) {
1217            self.update(|this| {
1218                let mut cx = ModelContext::new(this, handle.model_id);
1219                let result = update(
1220                    model
1221                        .as_any_mut()
1222                        .downcast_mut()
1223                        .expect("downcast is type safe"),
1224                    &mut cx,
1225                );
1226                this.models.insert(handle.model_id, model);
1227                result
1228            })
1229        } else {
1230            panic!("circular model update");
1231        }
1232    }
1233
1234    fn upgrade_model_handle<T: Entity>(
1235        &self,
1236        handle: &WeakModelHandle<T>,
1237    ) -> Option<ModelHandle<T>> {
1238        if self.ref_counts.lock().is_entity_alive(handle.model_id) {
1239            Some(ModelHandle::new(handle.model_id, &self.ref_counts))
1240        } else {
1241            None
1242        }
1243    }
1244
1245    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
1246        self.ref_counts.lock().is_entity_alive(handle.model_id)
1247    }
1248
1249    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
1250        if self.ref_counts.lock().is_entity_alive(handle.model_id) {
1251            Some(AnyModelHandle::new(
1252                handle.model_id,
1253                handle.model_type,
1254                self.ref_counts.clone(),
1255            ))
1256        } else {
1257            None
1258        }
1259    }
1260
1261    pub fn add_window<V, F>(
1262        &mut self,
1263        window_options: WindowOptions,
1264        build_root_view: F,
1265    ) -> (usize, ViewHandle<V>)
1266    where
1267        V: View,
1268        F: FnOnce(&mut ViewContext<V>) -> V,
1269    {
1270        self.update(|this| {
1271            let window_id = post_inc(&mut this.next_window_id);
1272            let platform_window =
1273                this.platform
1274                    .open_window(window_id, window_options, this.foreground.clone());
1275            let window = this.build_window(window_id, platform_window, build_root_view);
1276            let root_view = window.root_view().clone().downcast::<V>().unwrap();
1277            this.windows.insert(window_id, window);
1278            (window_id, root_view)
1279        })
1280    }
1281
1282    pub fn add_status_bar_item<V, F>(&mut self, build_root_view: F) -> (usize, ViewHandle<V>)
1283    where
1284        V: View,
1285        F: FnOnce(&mut ViewContext<V>) -> V,
1286    {
1287        self.update(|this| {
1288            let window_id = post_inc(&mut this.next_window_id);
1289            let platform_window = this.platform.add_status_item(window_id);
1290            let window = this.build_window(window_id, platform_window, build_root_view);
1291            let root_view = window.root_view().clone().downcast::<V>().unwrap();
1292
1293            this.windows.insert(window_id, window);
1294            this.update_window(window_id, |cx| {
1295                root_view.update(cx, |view, cx| view.focus_in(cx.handle().into_any(), cx))
1296            });
1297
1298            (window_id, root_view)
1299        })
1300    }
1301
1302    pub fn build_window<V, F>(
1303        &mut self,
1304        window_id: usize,
1305        mut platform_window: Box<dyn platform::Window>,
1306        build_root_view: F,
1307    ) -> Window
1308    where
1309        V: View,
1310        F: FnOnce(&mut ViewContext<V>) -> V,
1311    {
1312        {
1313            let mut app = self.upgrade();
1314
1315            platform_window.on_event(Box::new(move |event| {
1316                app.update_window(window_id, |cx| {
1317                    if let Event::KeyDown(KeyDownEvent { keystroke, .. }) = &event {
1318                        if cx.dispatch_keystroke(keystroke) {
1319                            return true;
1320                        }
1321                    }
1322
1323                    cx.dispatch_event(event, false)
1324                })
1325                .unwrap_or(false)
1326            }));
1327        }
1328
1329        {
1330            let mut app = self.upgrade();
1331            platform_window.on_active_status_change(Box::new(move |is_active| {
1332                app.update(|cx| cx.window_changed_active_status(window_id, is_active))
1333            }));
1334        }
1335
1336        {
1337            let mut app = self.upgrade();
1338            platform_window.on_resize(Box::new(move || {
1339                app.update(|cx| cx.window_was_resized(window_id))
1340            }));
1341        }
1342
1343        {
1344            let mut app = self.upgrade();
1345            platform_window.on_moved(Box::new(move || {
1346                app.update(|cx| cx.window_was_moved(window_id))
1347            }));
1348        }
1349
1350        {
1351            let mut app = self.upgrade();
1352            platform_window.on_fullscreen(Box::new(move |is_fullscreen| {
1353                app.update(|cx| cx.window_was_fullscreen_changed(window_id, is_fullscreen))
1354            }));
1355        }
1356
1357        {
1358            let mut app = self.upgrade();
1359            platform_window.on_close(Box::new(move || {
1360                app.update(|cx| cx.update_window(window_id, |cx| cx.remove_window()));
1361            }));
1362        }
1363
1364        {
1365            let mut app = self.upgrade();
1366            platform_window
1367                .on_appearance_changed(Box::new(move || app.update(|cx| cx.refresh_windows())));
1368        }
1369
1370        platform_window.set_input_handler(Box::new(WindowInputHandler {
1371            app: self.upgrade().0,
1372            window_id,
1373        }));
1374
1375        let mut window = Window::new(window_id, platform_window, self, build_root_view);
1376        let mut cx = WindowContext::mutable(self, &mut window, window_id);
1377        cx.layout(false).expect("initial layout should not error");
1378        let scene = cx.paint().expect("initial paint should not error");
1379        window.platform_window.present_scene(scene);
1380        window
1381    }
1382
1383    pub fn replace_root_view<V, F>(
1384        &mut self,
1385        window_id: usize,
1386        build_root_view: F,
1387    ) -> Option<ViewHandle<V>>
1388    where
1389        V: View,
1390        F: FnOnce(&mut ViewContext<V>) -> V,
1391    {
1392        self.update_window(window_id, |cx| cx.replace_root_view(build_root_view))
1393    }
1394
1395    pub fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
1396        if let Some(view) = self.views.get(&(handle.window_id, handle.view_id)) {
1397            view.as_any().downcast_ref().expect("downcast is type safe")
1398        } else {
1399            panic!("circular view reference for type {}", type_name::<T>());
1400        }
1401    }
1402
1403    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
1404        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
1405            Some(ViewHandle::new(
1406                handle.window_id,
1407                handle.view_id,
1408                &self.ref_counts,
1409            ))
1410        } else {
1411            None
1412        }
1413    }
1414
1415    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
1416        if self.ref_counts.lock().is_entity_alive(handle.view_id) {
1417            Some(AnyViewHandle::new(
1418                handle.window_id,
1419                handle.view_id,
1420                handle.view_type,
1421                self.ref_counts.clone(),
1422            ))
1423        } else {
1424            None
1425        }
1426    }
1427
1428    fn remove_dropped_entities(&mut self) {
1429        loop {
1430            let (dropped_models, dropped_views, dropped_element_states) =
1431                self.ref_counts.lock().take_dropped();
1432            if dropped_models.is_empty()
1433                && dropped_views.is_empty()
1434                && dropped_element_states.is_empty()
1435            {
1436                break;
1437            }
1438
1439            for model_id in dropped_models {
1440                self.subscriptions.remove(model_id);
1441                self.observations.remove(model_id);
1442                let mut model = self.models.remove(&model_id).unwrap();
1443                model.release(self);
1444                self.pending_effects
1445                    .push_back(Effect::ModelRelease { model_id, model });
1446            }
1447
1448            for (window_id, view_id) in dropped_views {
1449                self.subscriptions.remove(view_id);
1450                self.observations.remove(view_id);
1451                self.views_metadata.remove(&(window_id, view_id));
1452                let mut view = self.views.remove(&(window_id, view_id)).unwrap();
1453                view.release(self);
1454                if let Some(window) = self.windows.get_mut(&window_id) {
1455                    window.parents.remove(&view_id);
1456                    window
1457                        .invalidation
1458                        .get_or_insert_with(Default::default)
1459                        .removed
1460                        .push(view_id);
1461                }
1462
1463                self.pending_effects
1464                    .push_back(Effect::ViewRelease { view_id, view });
1465            }
1466
1467            for key in dropped_element_states {
1468                self.element_states.remove(&key);
1469            }
1470        }
1471    }
1472
1473    fn flush_effects(&mut self) {
1474        self.pending_flushes = self.pending_flushes.saturating_sub(1);
1475        let mut after_window_update_callbacks = Vec::new();
1476
1477        if !self.flushing_effects && self.pending_flushes == 0 {
1478            self.flushing_effects = true;
1479
1480            let mut refreshing = false;
1481            let mut updated_windows = HashSet::default();
1482            let mut focus_effects = HashMap::<usize, FocusEffect>::default();
1483            loop {
1484                self.remove_dropped_entities();
1485                if let Some(effect) = self.pending_effects.pop_front() {
1486                    match effect {
1487                        Effect::Subscription {
1488                            entity_id,
1489                            subscription_id,
1490                            callback,
1491                        } => self
1492                            .subscriptions
1493                            .add_callback(entity_id, subscription_id, callback),
1494
1495                        Effect::Event { entity_id, payload } => {
1496                            let mut subscriptions = self.subscriptions.clone();
1497                            subscriptions
1498                                .emit(entity_id, |callback| callback(payload.as_ref(), self))
1499                        }
1500
1501                        Effect::GlobalSubscription {
1502                            type_id,
1503                            subscription_id,
1504                            callback,
1505                        } => self.global_subscriptions.add_callback(
1506                            type_id,
1507                            subscription_id,
1508                            callback,
1509                        ),
1510
1511                        Effect::GlobalEvent { payload } => self.emit_global_event(payload),
1512
1513                        Effect::Observation {
1514                            entity_id,
1515                            subscription_id,
1516                            callback,
1517                        } => self
1518                            .observations
1519                            .add_callback(entity_id, subscription_id, callback),
1520
1521                        Effect::ModelNotification { model_id } => {
1522                            let mut observations = self.observations.clone();
1523                            observations.emit(model_id, |callback| callback(self));
1524                        }
1525
1526                        Effect::ViewNotification { window_id, view_id } => {
1527                            self.handle_view_notification_effect(window_id, view_id)
1528                        }
1529
1530                        Effect::GlobalNotification { type_id } => {
1531                            let mut subscriptions = self.global_observations.clone();
1532                            subscriptions.emit(type_id, |callback| {
1533                                callback(self);
1534                                true
1535                            });
1536                        }
1537
1538                        Effect::Deferred {
1539                            callback,
1540                            after_window_update,
1541                        } => {
1542                            if after_window_update {
1543                                after_window_update_callbacks.push(callback);
1544                            } else {
1545                                callback(self)
1546                            }
1547                        }
1548
1549                        Effect::ModelRelease { model_id, model } => {
1550                            self.handle_entity_release_effect(model_id, model.as_any())
1551                        }
1552
1553                        Effect::ViewRelease { view_id, view } => {
1554                            self.handle_entity_release_effect(view_id, view.as_any())
1555                        }
1556
1557                        Effect::Focus(mut effect) => {
1558                            if focus_effects
1559                                .get(&effect.window_id())
1560                                .map_or(false, |prev_effect| prev_effect.is_forced())
1561                            {
1562                                effect.force();
1563                            }
1564
1565                            focus_effects.insert(effect.window_id(), effect);
1566                        }
1567
1568                        Effect::FocusObservation {
1569                            view_id,
1570                            subscription_id,
1571                            callback,
1572                        } => {
1573                            self.focus_observations.add_callback(
1574                                view_id,
1575                                subscription_id,
1576                                callback,
1577                            );
1578                        }
1579
1580                        Effect::ResizeWindow { window_id } => {
1581                            if let Some(window) = self.windows.get_mut(&window_id) {
1582                                window
1583                                    .invalidation
1584                                    .get_or_insert(WindowInvalidation::default());
1585                            }
1586                            self.handle_window_moved(window_id);
1587                        }
1588
1589                        Effect::MoveWindow { window_id } => {
1590                            self.handle_window_moved(window_id);
1591                        }
1592
1593                        Effect::WindowActivationObservation {
1594                            window_id,
1595                            subscription_id,
1596                            callback,
1597                        } => self.window_activation_observations.add_callback(
1598                            window_id,
1599                            subscription_id,
1600                            callback,
1601                        ),
1602
1603                        Effect::ActivateWindow {
1604                            window_id,
1605                            is_active,
1606                        } => {
1607                            if self.handle_window_activation_effect(window_id, is_active)
1608                                && is_active
1609                            {
1610                                focus_effects
1611                                    .entry(window_id)
1612                                    .or_insert_with(|| FocusEffect::View {
1613                                        window_id,
1614                                        view_id: self
1615                                            .read_window(window_id, |cx| cx.focused_view_id())
1616                                            .flatten(),
1617                                        is_forced: true,
1618                                    })
1619                                    .force();
1620                            }
1621                        }
1622
1623                        Effect::WindowFullscreenObservation {
1624                            window_id,
1625                            subscription_id,
1626                            callback,
1627                        } => self.window_fullscreen_observations.add_callback(
1628                            window_id,
1629                            subscription_id,
1630                            callback,
1631                        ),
1632
1633                        Effect::FullscreenWindow {
1634                            window_id,
1635                            is_fullscreen,
1636                        } => self.handle_fullscreen_effect(window_id, is_fullscreen),
1637
1638                        Effect::WindowBoundsObservation {
1639                            window_id,
1640                            subscription_id,
1641                            callback,
1642                        } => self.window_bounds_observations.add_callback(
1643                            window_id,
1644                            subscription_id,
1645                            callback,
1646                        ),
1647
1648                        Effect::RefreshWindows => {
1649                            refreshing = true;
1650                        }
1651
1652                        Effect::ActionDispatchNotification { action_id } => {
1653                            self.handle_action_dispatch_notification_effect(action_id)
1654                        }
1655                        Effect::WindowShouldCloseSubscription {
1656                            window_id,
1657                            callback,
1658                        } => {
1659                            self.handle_window_should_close_subscription_effect(window_id, callback)
1660                        }
1661                        Effect::Keystroke {
1662                            window_id,
1663                            keystroke,
1664                            handled_by,
1665                            result,
1666                        } => self.handle_keystroke_effect(window_id, keystroke, handled_by, result),
1667                        Effect::ActiveLabeledTasksChanged => {
1668                            self.handle_active_labeled_tasks_changed_effect()
1669                        }
1670                        Effect::ActiveLabeledTasksObservation {
1671                            subscription_id,
1672                            callback,
1673                        } => self.active_labeled_task_observations.add_callback(
1674                            (),
1675                            subscription_id,
1676                            callback,
1677                        ),
1678                    }
1679                    self.pending_notifications.clear();
1680                } else {
1681                    for window_id in self.windows.keys().cloned().collect::<Vec<_>>() {
1682                        self.update_window(window_id, |cx| {
1683                            let invalidation = if refreshing {
1684                                let mut invalidation =
1685                                    cx.window.invalidation.take().unwrap_or_default();
1686                                invalidation
1687                                    .updated
1688                                    .extend(cx.window.rendered_views.keys().copied());
1689                                Some(invalidation)
1690                            } else {
1691                                cx.window.invalidation.take()
1692                            };
1693
1694                            if let Some(invalidation) = invalidation {
1695                                let appearance = cx.window.platform_window.appearance();
1696                                cx.invalidate(invalidation, appearance);
1697                                if cx.layout(refreshing).log_err().is_some() {
1698                                    updated_windows.insert(window_id);
1699
1700                                    // When the previously-focused view isn't rendered and
1701                                    // there isn't any pending focus, focus the root view.
1702                                    if let Some(focused_view_id) = cx.focused_view_id() {
1703                                        let root_view_id = cx.window.root_view().id();
1704                                        if focused_view_id != root_view_id
1705                                            && !cx.window.parents.contains_key(&focused_view_id)
1706                                            && !focus_effects.contains_key(&window_id)
1707                                        {
1708                                            focus_effects.insert(
1709                                                window_id,
1710                                                FocusEffect::View {
1711                                                    window_id,
1712                                                    view_id: Some(root_view_id),
1713                                                    is_forced: false,
1714                                                },
1715                                            );
1716                                        }
1717                                    }
1718                                }
1719                            }
1720                        });
1721                    }
1722
1723                    for (_, effect) in focus_effects.drain() {
1724                        self.handle_focus_effect(effect);
1725                    }
1726
1727                    if self.pending_effects.is_empty() {
1728                        for callback in after_window_update_callbacks.drain(..) {
1729                            callback(self);
1730                        }
1731
1732                        for window_id in updated_windows.drain() {
1733                            self.update_window(window_id, |cx| {
1734                                if let Some(scene) = cx.paint().log_err() {
1735                                    cx.window.platform_window.present_scene(scene);
1736                                }
1737                            });
1738                        }
1739
1740                        if self.pending_effects.is_empty() {
1741                            self.flushing_effects = false;
1742                            self.pending_notifications.clear();
1743                            self.pending_global_notifications.clear();
1744                            break;
1745                        }
1746                    }
1747
1748                    refreshing = false;
1749                }
1750            }
1751        }
1752    }
1753
1754    fn window_was_resized(&mut self, window_id: usize) {
1755        self.pending_effects
1756            .push_back(Effect::ResizeWindow { window_id });
1757    }
1758
1759    fn window_was_moved(&mut self, window_id: usize) {
1760        self.pending_effects
1761            .push_back(Effect::MoveWindow { window_id });
1762    }
1763
1764    fn window_was_fullscreen_changed(&mut self, window_id: usize, is_fullscreen: bool) {
1765        self.pending_effects.push_back(Effect::FullscreenWindow {
1766            window_id,
1767            is_fullscreen,
1768        });
1769    }
1770
1771    fn window_changed_active_status(&mut self, window_id: usize, is_active: bool) {
1772        self.pending_effects.push_back(Effect::ActivateWindow {
1773            window_id,
1774            is_active,
1775        });
1776    }
1777
1778    fn keystroke(
1779        &mut self,
1780        window_id: usize,
1781        keystroke: Keystroke,
1782        handled_by: Option<Box<dyn Action>>,
1783        result: MatchResult,
1784    ) {
1785        self.pending_effects.push_back(Effect::Keystroke {
1786            window_id,
1787            keystroke,
1788            handled_by,
1789            result,
1790        });
1791    }
1792
1793    pub fn refresh_windows(&mut self) {
1794        self.pending_effects.push_back(Effect::RefreshWindows);
1795    }
1796
1797    fn emit_global_event(&mut self, payload: Box<dyn Any>) {
1798        let type_id = (&*payload).type_id();
1799
1800        let mut subscriptions = self.global_subscriptions.clone();
1801        subscriptions.emit(type_id, |callback| {
1802            callback(payload.as_ref(), self);
1803            true //Always alive
1804        });
1805    }
1806
1807    fn handle_view_notification_effect(
1808        &mut self,
1809        observed_window_id: usize,
1810        observed_view_id: usize,
1811    ) {
1812        let view_key = (observed_window_id, observed_view_id);
1813        if let Some((view, mut view_metadata)) = self
1814            .views
1815            .remove(&view_key)
1816            .zip(self.views_metadata.remove(&view_key))
1817        {
1818            if let Some(window) = self.windows.get_mut(&observed_window_id) {
1819                window
1820                    .invalidation
1821                    .get_or_insert_with(Default::default)
1822                    .updated
1823                    .insert(observed_view_id);
1824            }
1825
1826            view.update_keymap_context(&mut view_metadata.keymap_context, self);
1827            self.views.insert(view_key, view);
1828            self.views_metadata.insert(view_key, view_metadata);
1829
1830            let mut observations = self.observations.clone();
1831            observations.emit(observed_view_id, |callback| callback(self));
1832        }
1833    }
1834
1835    fn handle_entity_release_effect(&mut self, entity_id: usize, entity: &dyn Any) {
1836        self.release_observations
1837            .clone()
1838            .emit(entity_id, |callback| {
1839                callback(entity, self);
1840                // Release observations happen one time. So clear the callback by returning false
1841                false
1842            })
1843    }
1844
1845    fn handle_fullscreen_effect(&mut self, window_id: usize, is_fullscreen: bool) {
1846        self.update_window(window_id, |cx| {
1847            cx.window.is_fullscreen = is_fullscreen;
1848
1849            let mut fullscreen_observations = cx.window_fullscreen_observations.clone();
1850            fullscreen_observations.emit(window_id, |callback| callback(is_fullscreen, cx));
1851
1852            if let Some(uuid) = cx.window_display_uuid() {
1853                let bounds = cx.window_bounds();
1854                let mut bounds_observations = cx.window_bounds_observations.clone();
1855                bounds_observations.emit(window_id, |callback| callback(bounds, uuid, cx));
1856            }
1857
1858            Some(())
1859        });
1860    }
1861
1862    fn handle_keystroke_effect(
1863        &mut self,
1864        window_id: usize,
1865        keystroke: Keystroke,
1866        handled_by: Option<Box<dyn Action>>,
1867        result: MatchResult,
1868    ) {
1869        self.update_window(window_id, |cx| {
1870            let mut observations = cx.keystroke_observations.clone();
1871            observations.emit(window_id, move |callback| {
1872                callback(&keystroke, &result, handled_by.as_ref(), cx)
1873            });
1874        });
1875    }
1876
1877    fn handle_window_activation_effect(&mut self, window_id: usize, active: bool) -> bool {
1878        self.update_window(window_id, |cx| {
1879            if cx.window.is_active == active {
1880                return false;
1881            }
1882            cx.window.is_active = active;
1883
1884            let mut observations = cx.window_activation_observations.clone();
1885            observations.emit(window_id, |callback| callback(active, cx));
1886            true
1887        })
1888        .unwrap_or(false)
1889    }
1890
1891    fn handle_focus_effect(&mut self, effect: FocusEffect) {
1892        let window_id = effect.window_id();
1893        self.update_window(window_id, |cx| {
1894            // Ensure the newly-focused view has been rendered, otherwise focus
1895            // the root view instead.
1896            let focused_id = match effect {
1897                FocusEffect::View { view_id, .. } => {
1898                    if let Some(view_id) = view_id {
1899                        if cx.window.parents.contains_key(&view_id) {
1900                            Some(view_id)
1901                        } else {
1902                            Some(cx.root_view().id())
1903                        }
1904                    } else {
1905                        None
1906                    }
1907                }
1908                FocusEffect::ViewParent { view_id, .. } => Some(
1909                    cx.window
1910                        .parents
1911                        .get(&view_id)
1912                        .copied()
1913                        .unwrap_or(cx.root_view().id()),
1914                ),
1915            };
1916
1917            let focus_changed = cx.window.focused_view_id != focused_id;
1918            let blurred_id = cx.window.focused_view_id;
1919            cx.window.focused_view_id = focused_id;
1920
1921            if focus_changed {
1922                if let Some(blurred_id) = blurred_id {
1923                    for view_id in cx.ancestors(blurred_id).collect::<Vec<_>>() {
1924                        if let Some(mut view) = cx.views.remove(&(window_id, view_id)) {
1925                            view.focus_out(blurred_id, cx, view_id);
1926                            cx.views.insert((window_id, view_id), view);
1927                        }
1928                    }
1929
1930                    let mut subscriptions = cx.focus_observations.clone();
1931                    subscriptions.emit(blurred_id, |callback| callback(false, cx));
1932                }
1933            }
1934
1935            if focus_changed || effect.is_forced() {
1936                if let Some(focused_id) = focused_id {
1937                    for view_id in cx.ancestors(focused_id).collect::<Vec<_>>() {
1938                        if let Some(mut view) = cx.views.remove(&(window_id, view_id)) {
1939                            view.focus_in(focused_id, cx, view_id);
1940                            cx.views.insert((window_id, view_id), view);
1941                        }
1942                    }
1943
1944                    let mut subscriptions = cx.focus_observations.clone();
1945                    subscriptions.emit(focused_id, |callback| callback(true, cx));
1946                }
1947            }
1948        });
1949    }
1950
1951    fn handle_action_dispatch_notification_effect(&mut self, action_id: TypeId) {
1952        self.action_dispatch_observations
1953            .clone()
1954            .emit((), |callback| {
1955                callback(action_id, self);
1956                true
1957            });
1958    }
1959
1960    fn handle_window_should_close_subscription_effect(
1961        &mut self,
1962        window_id: usize,
1963        mut callback: WindowShouldCloseSubscriptionCallback,
1964    ) {
1965        let mut app = self.upgrade();
1966        if let Some(window) = self.windows.get_mut(&window_id) {
1967            window
1968                .platform_window
1969                .on_should_close(Box::new(move || app.update(|cx| callback(cx))))
1970        }
1971    }
1972
1973    fn handle_window_moved(&mut self, window_id: usize) {
1974        self.update_window(window_id, |cx| {
1975            if let Some(display) = cx.window_display_uuid() {
1976                let bounds = cx.window_bounds();
1977                cx.window_bounds_observations
1978                    .clone()
1979                    .emit(window_id, move |callback| {
1980                        callback(bounds, display, cx);
1981                        true
1982                    });
1983            }
1984        });
1985    }
1986
1987    fn handle_active_labeled_tasks_changed_effect(&mut self) {
1988        self.active_labeled_task_observations
1989            .clone()
1990            .emit((), move |callback| {
1991                callback(self);
1992                true
1993            });
1994    }
1995
1996    pub fn focus(&mut self, window_id: usize, view_id: Option<usize>) {
1997        self.pending_effects
1998            .push_back(Effect::Focus(FocusEffect::View {
1999                window_id,
2000                view_id,
2001                is_forced: false,
2002            }));
2003    }
2004
2005    fn spawn_internal<F, Fut, T>(&mut self, task_name: Option<&'static str>, f: F) -> Task<T>
2006    where
2007        F: FnOnce(AsyncAppContext) -> Fut,
2008        Fut: 'static + Future<Output = T>,
2009        T: 'static,
2010    {
2011        let label_id = task_name.map(|task_name| {
2012            let id = post_inc(&mut self.next_labeled_task_id);
2013            self.active_labeled_tasks.insert(id, task_name);
2014            self.pending_effects
2015                .push_back(Effect::ActiveLabeledTasksChanged);
2016            id
2017        });
2018
2019        let future = f(self.to_async());
2020        let cx = self.to_async();
2021        self.foreground.spawn(async move {
2022            let result = future.await;
2023            let mut cx = cx.0.borrow_mut();
2024
2025            if let Some(completed_label_id) = label_id {
2026                cx.active_labeled_tasks.remove(&completed_label_id);
2027                cx.pending_effects
2028                    .push_back(Effect::ActiveLabeledTasksChanged);
2029            }
2030            cx.flush_effects();
2031            result
2032        })
2033    }
2034
2035    pub fn spawn_labeled<F, Fut, T>(&mut self, task_name: &'static str, f: F) -> Task<T>
2036    where
2037        F: FnOnce(AsyncAppContext) -> Fut,
2038        Fut: 'static + Future<Output = T>,
2039        T: 'static,
2040    {
2041        self.spawn_internal(Some(task_name), f)
2042    }
2043
2044    pub fn spawn<F, Fut, T>(&mut self, f: F) -> Task<T>
2045    where
2046        F: FnOnce(AsyncAppContext) -> Fut,
2047        Fut: 'static + Future<Output = T>,
2048        T: 'static,
2049    {
2050        self.spawn_internal(None, f)
2051    }
2052
2053    pub fn to_async(&self) -> AsyncAppContext {
2054        AsyncAppContext(self.weak_self.as_ref().unwrap().upgrade().unwrap())
2055    }
2056
2057    pub fn write_to_clipboard(&self, item: ClipboardItem) {
2058        self.platform.write_to_clipboard(item);
2059    }
2060
2061    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
2062        self.platform.read_from_clipboard()
2063    }
2064
2065    #[cfg(any(test, feature = "test-support"))]
2066    pub fn leak_detector(&self) -> Arc<Mutex<LeakDetector>> {
2067        self.ref_counts.lock().leak_detector.clone()
2068    }
2069}
2070
2071impl BorrowAppContext for AppContext {
2072    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
2073        f(self)
2074    }
2075
2076    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
2077        f(self)
2078    }
2079}
2080
2081#[derive(Debug)]
2082pub enum ParentId {
2083    View(usize),
2084    Root,
2085}
2086
2087struct ViewMetadata {
2088    type_id: TypeId,
2089    keymap_context: KeymapContext,
2090}
2091
2092#[derive(Default, Clone)]
2093pub struct WindowInvalidation {
2094    pub updated: HashSet<usize>,
2095    pub removed: Vec<usize>,
2096}
2097
2098#[derive(Debug)]
2099pub enum FocusEffect {
2100    View {
2101        window_id: usize,
2102        view_id: Option<usize>,
2103        is_forced: bool,
2104    },
2105    ViewParent {
2106        window_id: usize,
2107        view_id: usize,
2108        is_forced: bool,
2109    },
2110}
2111
2112impl FocusEffect {
2113    fn window_id(&self) -> usize {
2114        match self {
2115            FocusEffect::View { window_id, .. } => *window_id,
2116            FocusEffect::ViewParent { window_id, .. } => *window_id,
2117        }
2118    }
2119
2120    fn is_forced(&self) -> bool {
2121        match self {
2122            FocusEffect::View { is_forced, .. } => *is_forced,
2123            FocusEffect::ViewParent { is_forced, .. } => *is_forced,
2124        }
2125    }
2126
2127    fn force(&mut self) {
2128        match self {
2129            FocusEffect::View { is_forced, .. } => *is_forced = true,
2130            FocusEffect::ViewParent { is_forced, .. } => *is_forced = true,
2131        }
2132    }
2133}
2134
2135pub enum Effect {
2136    Subscription {
2137        entity_id: usize,
2138        subscription_id: usize,
2139        callback: SubscriptionCallback,
2140    },
2141    Event {
2142        entity_id: usize,
2143        payload: Box<dyn Any>,
2144    },
2145    GlobalSubscription {
2146        type_id: TypeId,
2147        subscription_id: usize,
2148        callback: GlobalSubscriptionCallback,
2149    },
2150    GlobalEvent {
2151        payload: Box<dyn Any>,
2152    },
2153    Observation {
2154        entity_id: usize,
2155        subscription_id: usize,
2156        callback: ObservationCallback,
2157    },
2158    ModelNotification {
2159        model_id: usize,
2160    },
2161    ViewNotification {
2162        window_id: usize,
2163        view_id: usize,
2164    },
2165    Deferred {
2166        callback: Box<dyn FnOnce(&mut AppContext)>,
2167        after_window_update: bool,
2168    },
2169    GlobalNotification {
2170        type_id: TypeId,
2171    },
2172    ModelRelease {
2173        model_id: usize,
2174        model: Box<dyn AnyModel>,
2175    },
2176    ViewRelease {
2177        view_id: usize,
2178        view: Box<dyn AnyView>,
2179    },
2180    Focus(FocusEffect),
2181    FocusObservation {
2182        view_id: usize,
2183        subscription_id: usize,
2184        callback: FocusObservationCallback,
2185    },
2186    ResizeWindow {
2187        window_id: usize,
2188    },
2189    MoveWindow {
2190        window_id: usize,
2191    },
2192    ActivateWindow {
2193        window_id: usize,
2194        is_active: bool,
2195    },
2196    WindowActivationObservation {
2197        window_id: usize,
2198        subscription_id: usize,
2199        callback: WindowActivationCallback,
2200    },
2201    FullscreenWindow {
2202        window_id: usize,
2203        is_fullscreen: bool,
2204    },
2205    WindowFullscreenObservation {
2206        window_id: usize,
2207        subscription_id: usize,
2208        callback: WindowFullscreenCallback,
2209    },
2210    WindowBoundsObservation {
2211        window_id: usize,
2212        subscription_id: usize,
2213        callback: WindowBoundsCallback,
2214    },
2215    Keystroke {
2216        window_id: usize,
2217        keystroke: Keystroke,
2218        handled_by: Option<Box<dyn Action>>,
2219        result: MatchResult,
2220    },
2221    RefreshWindows,
2222    ActionDispatchNotification {
2223        action_id: TypeId,
2224    },
2225    WindowShouldCloseSubscription {
2226        window_id: usize,
2227        callback: WindowShouldCloseSubscriptionCallback,
2228    },
2229    ActiveLabeledTasksChanged,
2230    ActiveLabeledTasksObservation {
2231        subscription_id: usize,
2232        callback: ActiveLabeledTasksCallback,
2233    },
2234}
2235
2236impl Debug for Effect {
2237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2238        match self {
2239            Effect::Subscription {
2240                entity_id,
2241                subscription_id,
2242                ..
2243            } => f
2244                .debug_struct("Effect::Subscribe")
2245                .field("entity_id", entity_id)
2246                .field("subscription_id", subscription_id)
2247                .finish(),
2248            Effect::Event { entity_id, .. } => f
2249                .debug_struct("Effect::Event")
2250                .field("entity_id", entity_id)
2251                .finish(),
2252            Effect::GlobalSubscription {
2253                type_id,
2254                subscription_id,
2255                ..
2256            } => f
2257                .debug_struct("Effect::Subscribe")
2258                .field("type_id", type_id)
2259                .field("subscription_id", subscription_id)
2260                .finish(),
2261            Effect::GlobalEvent { payload, .. } => f
2262                .debug_struct("Effect::GlobalEvent")
2263                .field("type_id", &(&*payload).type_id())
2264                .finish(),
2265            Effect::Observation {
2266                entity_id,
2267                subscription_id,
2268                ..
2269            } => f
2270                .debug_struct("Effect::Observation")
2271                .field("entity_id", entity_id)
2272                .field("subscription_id", subscription_id)
2273                .finish(),
2274            Effect::ModelNotification { model_id } => f
2275                .debug_struct("Effect::ModelNotification")
2276                .field("model_id", model_id)
2277                .finish(),
2278            Effect::ViewNotification { window_id, view_id } => f
2279                .debug_struct("Effect::ViewNotification")
2280                .field("window_id", window_id)
2281                .field("view_id", view_id)
2282                .finish(),
2283            Effect::GlobalNotification { type_id } => f
2284                .debug_struct("Effect::GlobalNotification")
2285                .field("type_id", type_id)
2286                .finish(),
2287            Effect::Deferred { .. } => f.debug_struct("Effect::Deferred").finish(),
2288            Effect::ModelRelease { model_id, .. } => f
2289                .debug_struct("Effect::ModelRelease")
2290                .field("model_id", model_id)
2291                .finish(),
2292            Effect::ViewRelease { view_id, .. } => f
2293                .debug_struct("Effect::ViewRelease")
2294                .field("view_id", view_id)
2295                .finish(),
2296            Effect::Focus(focus) => f.debug_tuple("Effect::Focus").field(focus).finish(),
2297            Effect::FocusObservation {
2298                view_id,
2299                subscription_id,
2300                ..
2301            } => f
2302                .debug_struct("Effect::FocusObservation")
2303                .field("view_id", view_id)
2304                .field("subscription_id", subscription_id)
2305                .finish(),
2306            Effect::ActionDispatchNotification { action_id, .. } => f
2307                .debug_struct("Effect::ActionDispatchNotification")
2308                .field("action_id", action_id)
2309                .finish(),
2310            Effect::ResizeWindow { window_id } => f
2311                .debug_struct("Effect::RefreshWindow")
2312                .field("window_id", window_id)
2313                .finish(),
2314            Effect::MoveWindow { window_id } => f
2315                .debug_struct("Effect::MoveWindow")
2316                .field("window_id", window_id)
2317                .finish(),
2318            Effect::WindowActivationObservation {
2319                window_id,
2320                subscription_id,
2321                ..
2322            } => f
2323                .debug_struct("Effect::WindowActivationObservation")
2324                .field("window_id", window_id)
2325                .field("subscription_id", subscription_id)
2326                .finish(),
2327            Effect::ActivateWindow {
2328                window_id,
2329                is_active,
2330            } => f
2331                .debug_struct("Effect::ActivateWindow")
2332                .field("window_id", window_id)
2333                .field("is_active", is_active)
2334                .finish(),
2335            Effect::FullscreenWindow {
2336                window_id,
2337                is_fullscreen,
2338            } => f
2339                .debug_struct("Effect::FullscreenWindow")
2340                .field("window_id", window_id)
2341                .field("is_fullscreen", is_fullscreen)
2342                .finish(),
2343            Effect::WindowFullscreenObservation {
2344                window_id,
2345                subscription_id,
2346                callback: _,
2347            } => f
2348                .debug_struct("Effect::WindowFullscreenObservation")
2349                .field("window_id", window_id)
2350                .field("subscription_id", subscription_id)
2351                .finish(),
2352
2353            Effect::WindowBoundsObservation {
2354                window_id,
2355                subscription_id,
2356                callback: _,
2357            } => f
2358                .debug_struct("Effect::WindowBoundsObservation")
2359                .field("window_id", window_id)
2360                .field("subscription_id", subscription_id)
2361                .finish(),
2362            Effect::RefreshWindows => f.debug_struct("Effect::FullViewRefresh").finish(),
2363            Effect::WindowShouldCloseSubscription { window_id, .. } => f
2364                .debug_struct("Effect::WindowShouldCloseSubscription")
2365                .field("window_id", window_id)
2366                .finish(),
2367            Effect::Keystroke {
2368                window_id,
2369                keystroke,
2370                handled_by,
2371                result,
2372            } => f
2373                .debug_struct("Effect::Keystroke")
2374                .field("window_id", window_id)
2375                .field("keystroke", keystroke)
2376                .field(
2377                    "keystroke",
2378                    &handled_by.as_ref().map(|handled_by| handled_by.name()),
2379                )
2380                .field("result", result)
2381                .finish(),
2382            Effect::ActiveLabeledTasksChanged => {
2383                f.debug_struct("Effect::ActiveLabeledTasksChanged").finish()
2384            }
2385            Effect::ActiveLabeledTasksObservation {
2386                subscription_id,
2387                callback: _,
2388            } => f
2389                .debug_struct("Effect::ActiveLabeledTasksObservation")
2390                .field("subscription_id", subscription_id)
2391                .finish(),
2392        }
2393    }
2394}
2395
2396pub trait AnyModel {
2397    fn as_any(&self) -> &dyn Any;
2398    fn as_any_mut(&mut self) -> &mut dyn Any;
2399    fn release(&mut self, cx: &mut AppContext);
2400    fn app_will_quit(
2401        &mut self,
2402        cx: &mut AppContext,
2403    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
2404}
2405
2406impl<T> AnyModel for T
2407where
2408    T: Entity,
2409{
2410    fn as_any(&self) -> &dyn Any {
2411        self
2412    }
2413
2414    fn as_any_mut(&mut self) -> &mut dyn Any {
2415        self
2416    }
2417
2418    fn release(&mut self, cx: &mut AppContext) {
2419        self.release(cx);
2420    }
2421
2422    fn app_will_quit(
2423        &mut self,
2424        cx: &mut AppContext,
2425    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
2426        self.app_will_quit(cx)
2427    }
2428}
2429
2430pub trait AnyView {
2431    fn as_any(&self) -> &dyn Any;
2432    fn as_any_mut(&mut self) -> &mut dyn Any;
2433    fn release(&mut self, cx: &mut AppContext);
2434    fn app_will_quit(
2435        &mut self,
2436        cx: &mut AppContext,
2437    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
2438    fn ui_name(&self) -> &'static str;
2439    fn render(&mut self, cx: &mut WindowContext, view_id: usize) -> Box<dyn AnyRootElement>;
2440    fn focus_in<'a, 'b>(&mut self, focused_id: usize, cx: &mut WindowContext<'a>, view_id: usize);
2441    fn focus_out(&mut self, focused_id: usize, cx: &mut WindowContext, view_id: usize);
2442    fn key_down(&mut self, event: &KeyDownEvent, cx: &mut WindowContext, view_id: usize) -> bool;
2443    fn key_up(&mut self, event: &KeyUpEvent, cx: &mut WindowContext, view_id: usize) -> bool;
2444    fn modifiers_changed(
2445        &mut self,
2446        event: &ModifiersChangedEvent,
2447        cx: &mut WindowContext,
2448        view_id: usize,
2449    ) -> bool;
2450    fn update_keymap_context(&self, keymap: &mut KeymapContext, cx: &AppContext);
2451    fn debug_json(&self, cx: &WindowContext) -> serde_json::Value;
2452
2453    fn text_for_range(&self, range: Range<usize>, cx: &WindowContext) -> Option<String>;
2454    fn selected_text_range(&self, cx: &WindowContext) -> Option<Range<usize>>;
2455    fn marked_text_range(&self, cx: &WindowContext) -> Option<Range<usize>>;
2456    fn unmark_text(&mut self, cx: &mut WindowContext, view_id: usize);
2457    fn replace_text_in_range(
2458        &mut self,
2459        range: Option<Range<usize>>,
2460        text: &str,
2461        cx: &mut WindowContext,
2462        view_id: usize,
2463    );
2464    fn replace_and_mark_text_in_range(
2465        &mut self,
2466        range: Option<Range<usize>>,
2467        new_text: &str,
2468        new_selected_range: Option<Range<usize>>,
2469        cx: &mut WindowContext,
2470        view_id: usize,
2471    );
2472    fn any_handle(&self, window_id: usize, view_id: usize, cx: &AppContext) -> AnyViewHandle {
2473        AnyViewHandle::new(
2474            window_id,
2475            view_id,
2476            self.as_any().type_id(),
2477            cx.ref_counts.clone(),
2478        )
2479    }
2480}
2481
2482impl<V> AnyView for V
2483where
2484    V: View,
2485{
2486    fn as_any(&self) -> &dyn Any {
2487        self
2488    }
2489
2490    fn as_any_mut(&mut self) -> &mut dyn Any {
2491        self
2492    }
2493
2494    fn release(&mut self, cx: &mut AppContext) {
2495        self.release(cx);
2496    }
2497
2498    fn app_will_quit(
2499        &mut self,
2500        cx: &mut AppContext,
2501    ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>> {
2502        self.app_will_quit(cx)
2503    }
2504
2505    fn ui_name(&self) -> &'static str {
2506        V::ui_name()
2507    }
2508
2509    fn render(&mut self, cx: &mut WindowContext, view_id: usize) -> Box<dyn AnyRootElement> {
2510        let mut view_context = ViewContext::mutable(cx, view_id);
2511        let element = V::render(self, &mut view_context);
2512        let view = WeakViewHandle::new(cx.window_id, view_id);
2513        Box::new(RootElement::new(element, view))
2514    }
2515
2516    fn focus_in(&mut self, focused_id: usize, cx: &mut WindowContext, view_id: usize) {
2517        let mut cx = ViewContext::mutable(cx, view_id);
2518        let focused_view_handle: AnyViewHandle = if view_id == focused_id {
2519            cx.handle().into_any()
2520        } else {
2521            let focused_type = cx
2522                .views_metadata
2523                .get(&(cx.window_id, focused_id))
2524                .unwrap()
2525                .type_id;
2526            AnyViewHandle::new(
2527                cx.window_id,
2528                focused_id,
2529                focused_type,
2530                cx.ref_counts.clone(),
2531            )
2532        };
2533        View::focus_in(self, focused_view_handle, &mut cx);
2534    }
2535
2536    fn focus_out(&mut self, blurred_id: usize, cx: &mut WindowContext, view_id: usize) {
2537        let mut cx = ViewContext::mutable(cx, view_id);
2538        let blurred_view_handle: AnyViewHandle = if view_id == blurred_id {
2539            cx.handle().into_any()
2540        } else {
2541            let blurred_type = cx
2542                .views_metadata
2543                .get(&(cx.window_id, blurred_id))
2544                .unwrap()
2545                .type_id;
2546            AnyViewHandle::new(
2547                cx.window_id,
2548                blurred_id,
2549                blurred_type,
2550                cx.ref_counts.clone(),
2551            )
2552        };
2553        View::focus_out(self, blurred_view_handle, &mut cx);
2554    }
2555
2556    fn key_down(&mut self, event: &KeyDownEvent, cx: &mut WindowContext, view_id: usize) -> bool {
2557        let mut cx = ViewContext::mutable(cx, view_id);
2558        View::key_down(self, event, &mut cx)
2559    }
2560
2561    fn key_up(&mut self, event: &KeyUpEvent, cx: &mut WindowContext, view_id: usize) -> bool {
2562        let mut cx = ViewContext::mutable(cx, view_id);
2563        View::key_up(self, event, &mut cx)
2564    }
2565
2566    fn modifiers_changed(
2567        &mut self,
2568        event: &ModifiersChangedEvent,
2569        cx: &mut WindowContext,
2570        view_id: usize,
2571    ) -> bool {
2572        let mut cx = ViewContext::mutable(cx, view_id);
2573        View::modifiers_changed(self, event, &mut cx)
2574    }
2575
2576    fn update_keymap_context(&self, keymap: &mut KeymapContext, cx: &AppContext) {
2577        View::update_keymap_context(self, keymap, cx)
2578    }
2579
2580    fn debug_json(&self, cx: &WindowContext) -> serde_json::Value {
2581        View::debug_json(self, cx)
2582    }
2583
2584    fn text_for_range(&self, range: Range<usize>, cx: &WindowContext) -> Option<String> {
2585        View::text_for_range(self, range, cx)
2586    }
2587
2588    fn selected_text_range(&self, cx: &WindowContext) -> Option<Range<usize>> {
2589        View::selected_text_range(self, cx)
2590    }
2591
2592    fn marked_text_range(&self, cx: &WindowContext) -> Option<Range<usize>> {
2593        View::marked_text_range(self, cx)
2594    }
2595
2596    fn unmark_text(&mut self, cx: &mut WindowContext, view_id: usize) {
2597        let mut cx = ViewContext::mutable(cx, view_id);
2598        View::unmark_text(self, &mut cx)
2599    }
2600
2601    fn replace_text_in_range(
2602        &mut self,
2603        range: Option<Range<usize>>,
2604        text: &str,
2605        cx: &mut WindowContext,
2606        view_id: usize,
2607    ) {
2608        let mut cx = ViewContext::mutable(cx, view_id);
2609        View::replace_text_in_range(self, range, text, &mut cx)
2610    }
2611
2612    fn replace_and_mark_text_in_range(
2613        &mut self,
2614        range: Option<Range<usize>>,
2615        new_text: &str,
2616        new_selected_range: Option<Range<usize>>,
2617        cx: &mut WindowContext,
2618        view_id: usize,
2619    ) {
2620        let mut cx = ViewContext::mutable(cx, view_id);
2621        View::replace_and_mark_text_in_range(self, range, new_text, new_selected_range, &mut cx)
2622    }
2623}
2624
2625pub struct ModelContext<'a, T: ?Sized> {
2626    app: &'a mut AppContext,
2627    model_id: usize,
2628    model_type: PhantomData<T>,
2629    halt_stream: bool,
2630}
2631
2632impl<'a, T: Entity> ModelContext<'a, T> {
2633    fn new(app: &'a mut AppContext, model_id: usize) -> Self {
2634        Self {
2635            app,
2636            model_id,
2637            model_type: PhantomData,
2638            halt_stream: false,
2639        }
2640    }
2641
2642    pub fn background(&self) -> &Arc<executor::Background> {
2643        &self.app.background
2644    }
2645
2646    pub fn halt_stream(&mut self) {
2647        self.halt_stream = true;
2648    }
2649
2650    pub fn model_id(&self) -> usize {
2651        self.model_id
2652    }
2653
2654    pub fn add_model<S, F>(&mut self, build_model: F) -> ModelHandle<S>
2655    where
2656        S: Entity,
2657        F: FnOnce(&mut ModelContext<S>) -> S,
2658    {
2659        self.app.add_model(build_model)
2660    }
2661
2662    pub fn emit(&mut self, payload: T::Event) {
2663        self.app.pending_effects.push_back(Effect::Event {
2664            entity_id: self.model_id,
2665            payload: Box::new(payload),
2666        });
2667    }
2668
2669    pub fn notify(&mut self) {
2670        self.app.notify_model(self.model_id);
2671    }
2672
2673    pub fn subscribe<S: Entity, F>(
2674        &mut self,
2675        handle: &ModelHandle<S>,
2676        mut callback: F,
2677    ) -> Subscription
2678    where
2679        S::Event: 'static,
2680        F: 'static + FnMut(&mut T, ModelHandle<S>, &S::Event, &mut ModelContext<T>),
2681    {
2682        let subscriber = self.weak_handle();
2683        self.app
2684            .subscribe_internal(handle, move |emitter, event, cx| {
2685                if let Some(subscriber) = subscriber.upgrade(cx) {
2686                    subscriber.update(cx, |subscriber, cx| {
2687                        callback(subscriber, emitter, event, cx);
2688                    });
2689                    true
2690                } else {
2691                    false
2692                }
2693            })
2694    }
2695
2696    pub fn observe<S, F>(&mut self, handle: &ModelHandle<S>, mut callback: F) -> Subscription
2697    where
2698        S: Entity,
2699        F: 'static + FnMut(&mut T, ModelHandle<S>, &mut ModelContext<T>),
2700    {
2701        let observer = self.weak_handle();
2702        self.app.observe_internal(handle, move |observed, cx| {
2703            if let Some(observer) = observer.upgrade(cx) {
2704                observer.update(cx, |observer, cx| {
2705                    callback(observer, observed, cx);
2706                });
2707                true
2708            } else {
2709                false
2710            }
2711        })
2712    }
2713
2714    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
2715    where
2716        G: Any,
2717        F: 'static + FnMut(&mut T, &mut ModelContext<T>),
2718    {
2719        let observer = self.weak_handle();
2720        self.app.observe_global::<G, _>(move |cx| {
2721            if let Some(observer) = observer.upgrade(cx) {
2722                observer.update(cx, |observer, cx| callback(observer, cx));
2723            }
2724        })
2725    }
2726
2727    pub fn observe_release<S, F>(
2728        &mut self,
2729        handle: &ModelHandle<S>,
2730        mut callback: F,
2731    ) -> Subscription
2732    where
2733        S: Entity,
2734        F: 'static + FnMut(&mut T, &S, &mut ModelContext<T>),
2735    {
2736        let observer = self.weak_handle();
2737        self.app.observe_release(handle, move |released, cx| {
2738            if let Some(observer) = observer.upgrade(cx) {
2739                observer.update(cx, |observer, cx| {
2740                    callback(observer, released, cx);
2741                });
2742            }
2743        })
2744    }
2745
2746    pub fn handle(&self) -> ModelHandle<T> {
2747        ModelHandle::new(self.model_id, &self.app.ref_counts)
2748    }
2749
2750    pub fn weak_handle(&self) -> WeakModelHandle<T> {
2751        WeakModelHandle::new(self.model_id)
2752    }
2753
2754    pub fn spawn<F, Fut, S>(&mut self, f: F) -> Task<S>
2755    where
2756        F: FnOnce(ModelHandle<T>, AsyncAppContext) -> Fut,
2757        Fut: 'static + Future<Output = S>,
2758        S: 'static,
2759    {
2760        let handle = self.handle();
2761        self.app.spawn(|cx| f(handle, cx))
2762    }
2763
2764    pub fn spawn_weak<F, Fut, S>(&mut self, f: F) -> Task<S>
2765    where
2766        F: FnOnce(WeakModelHandle<T>, AsyncAppContext) -> Fut,
2767        Fut: 'static + Future<Output = S>,
2768        S: 'static,
2769    {
2770        let handle = self.weak_handle();
2771        self.app.spawn(|cx| f(handle, cx))
2772    }
2773}
2774
2775impl<M> AsRef<AppContext> for ModelContext<'_, M> {
2776    fn as_ref(&self) -> &AppContext {
2777        &self.app
2778    }
2779}
2780
2781impl<M> AsMut<AppContext> for ModelContext<'_, M> {
2782    fn as_mut(&mut self) -> &mut AppContext {
2783        self.app
2784    }
2785}
2786
2787impl<M> BorrowAppContext for ModelContext<'_, M> {
2788    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
2789        self.app.read_with(f)
2790    }
2791
2792    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
2793        self.app.update(f)
2794    }
2795}
2796
2797impl<M> Deref for ModelContext<'_, M> {
2798    type Target = AppContext;
2799
2800    fn deref(&self) -> &Self::Target {
2801        self.app
2802    }
2803}
2804
2805impl<M> DerefMut for ModelContext<'_, M> {
2806    fn deref_mut(&mut self) -> &mut Self::Target {
2807        &mut self.app
2808    }
2809}
2810
2811pub struct ViewContext<'a, 'b, T: ?Sized> {
2812    window_context: Reference<'b, WindowContext<'a>>,
2813    view_id: usize,
2814    view_type: PhantomData<T>,
2815}
2816
2817impl<'a, 'b, T: View> Deref for ViewContext<'a, 'b, T> {
2818    type Target = WindowContext<'a>;
2819
2820    fn deref(&self) -> &Self::Target {
2821        &self.window_context
2822    }
2823}
2824
2825impl<T: View> DerefMut for ViewContext<'_, '_, T> {
2826    fn deref_mut(&mut self) -> &mut Self::Target {
2827        &mut self.window_context
2828    }
2829}
2830
2831impl<'a, 'b, V: View> ViewContext<'a, 'b, V> {
2832    pub(crate) fn mutable(window_context: &'b mut WindowContext<'a>, view_id: usize) -> Self {
2833        Self {
2834            window_context: Reference::Mutable(window_context),
2835            view_id,
2836            view_type: PhantomData,
2837        }
2838    }
2839
2840    pub(crate) fn immutable(window_context: &'b WindowContext<'a>, view_id: usize) -> Self {
2841        Self {
2842            window_context: Reference::Immutable(window_context),
2843            view_id,
2844            view_type: PhantomData,
2845        }
2846    }
2847
2848    pub fn window_context(&mut self) -> &mut WindowContext<'a> {
2849        &mut self.window_context
2850    }
2851
2852    pub fn handle(&self) -> ViewHandle<V> {
2853        ViewHandle::new(
2854            self.window_id,
2855            self.view_id,
2856            &self.window_context.ref_counts,
2857        )
2858    }
2859
2860    pub fn weak_handle(&self) -> WeakViewHandle<V> {
2861        WeakViewHandle::new(self.window_id, self.view_id)
2862    }
2863
2864    pub fn window_id(&self) -> usize {
2865        self.window_id
2866    }
2867
2868    pub fn view_id(&self) -> usize {
2869        self.view_id
2870    }
2871
2872    pub fn foreground(&self) -> &Rc<executor::Foreground> {
2873        self.window_context.foreground()
2874    }
2875
2876    pub fn background_executor(&self) -> &Arc<executor::Background> {
2877        &self.window_context.background
2878    }
2879
2880    pub fn platform(&self) -> &Arc<dyn Platform> {
2881        self.window_context.platform()
2882    }
2883
2884    pub fn prompt_for_paths(
2885        &self,
2886        options: PathPromptOptions,
2887    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
2888        self.window_context.prompt_for_paths(options)
2889    }
2890
2891    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
2892        self.window_context.prompt_for_new_path(directory)
2893    }
2894
2895    pub fn reveal_path(&self, path: &Path) {
2896        self.window_context.reveal_path(path)
2897    }
2898
2899    pub fn focus(&mut self, handle: &AnyViewHandle) {
2900        self.window_context
2901            .focus(handle.window_id, Some(handle.view_id));
2902    }
2903
2904    pub fn focus_self(&mut self) {
2905        let window_id = self.window_id;
2906        let view_id = self.view_id;
2907        self.window_context.focus(window_id, Some(view_id));
2908    }
2909
2910    pub fn is_self_focused(&self) -> bool {
2911        self.window.focused_view_id == Some(self.view_id)
2912    }
2913
2914    pub fn focus_parent(&mut self) {
2915        let window_id = self.window_id;
2916        let view_id = self.view_id;
2917        self.pending_effects
2918            .push_back(Effect::Focus(FocusEffect::ViewParent {
2919                window_id,
2920                view_id,
2921                is_forced: false,
2922            }));
2923    }
2924
2925    pub fn blur(&mut self) {
2926        let window_id = self.window_id;
2927        self.window_context.focus(window_id, None);
2928    }
2929
2930    pub fn on_window_should_close<F>(&mut self, mut callback: F)
2931    where
2932        F: 'static + FnMut(&mut V, &mut ViewContext<V>) -> bool,
2933    {
2934        let window_id = self.window_id;
2935        let view = self.weak_handle();
2936        self.pending_effects
2937            .push_back(Effect::WindowShouldCloseSubscription {
2938                window_id,
2939                callback: Box::new(move |cx| {
2940                    cx.update_window(window_id, |cx| {
2941                        if let Some(view) = view.upgrade(cx) {
2942                            view.update(cx, |view, cx| callback(view, cx))
2943                        } else {
2944                            true
2945                        }
2946                    })
2947                    .unwrap_or(true)
2948                }),
2949            });
2950    }
2951
2952    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
2953    where
2954        E: Entity,
2955        E::Event: 'static,
2956        H: Handle<E>,
2957        F: 'static + FnMut(&mut V, H, &E::Event, &mut ViewContext<V>),
2958    {
2959        let subscriber = self.weak_handle();
2960        self.window_context
2961            .subscribe_internal(handle, move |emitter, event, cx| {
2962                if let Some(subscriber) = subscriber.upgrade(cx) {
2963                    subscriber.update(cx, |subscriber, cx| {
2964                        callback(subscriber, emitter, event, cx);
2965                    });
2966                    true
2967                } else {
2968                    false
2969                }
2970            })
2971    }
2972
2973    pub fn observe<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
2974    where
2975        E: Entity,
2976        H: Handle<E>,
2977        F: 'static + FnMut(&mut V, H, &mut ViewContext<V>),
2978    {
2979        let window_id = self.window_id;
2980        let observer = self.weak_handle();
2981        self.window_context
2982            .observe_internal(handle, move |observed, cx| {
2983                cx.update_window(window_id, |cx| {
2984                    if let Some(observer) = observer.upgrade(cx) {
2985                        observer.update(cx, |observer, cx| {
2986                            callback(observer, observed, cx);
2987                        });
2988                        true
2989                    } else {
2990                        false
2991                    }
2992                })
2993                .unwrap_or(false)
2994            })
2995    }
2996
2997    pub fn observe_global<G, F>(&mut self, mut callback: F) -> Subscription
2998    where
2999        G: Any,
3000        F: 'static + FnMut(&mut V, &mut ViewContext<V>),
3001    {
3002        let window_id = self.window_id;
3003        let observer = self.weak_handle();
3004        self.window_context.observe_global::<G, _>(move |cx| {
3005            cx.update_window(window_id, |cx| {
3006                if let Some(observer) = observer.upgrade(cx) {
3007                    observer.update(cx, |observer, cx| callback(observer, cx));
3008                }
3009            });
3010        })
3011    }
3012
3013    pub fn observe_focus<F, W>(&mut self, handle: &ViewHandle<W>, mut callback: F) -> Subscription
3014    where
3015        F: 'static + FnMut(&mut V, ViewHandle<W>, bool, &mut ViewContext<V>),
3016        W: View,
3017    {
3018        let observer = self.weak_handle();
3019        self.window_context
3020            .observe_focus(handle, move |observed, focused, cx| {
3021                if let Some(observer) = observer.upgrade(cx) {
3022                    observer.update(cx, |observer, cx| {
3023                        callback(observer, observed, focused, cx);
3024                    });
3025                    true
3026                } else {
3027                    false
3028                }
3029            })
3030    }
3031
3032    pub fn observe_release<E, F, H>(&mut self, handle: &H, mut callback: F) -> Subscription
3033    where
3034        E: Entity,
3035        H: Handle<E>,
3036        F: 'static + FnMut(&mut V, &E, &mut ViewContext<V>),
3037    {
3038        let window_id = self.window_id;
3039        let observer = self.weak_handle();
3040        self.window_context
3041            .observe_release(handle, move |released, cx| {
3042                cx.update_window(window_id, |cx| {
3043                    if let Some(observer) = observer.upgrade(cx) {
3044                        observer.update(cx, |observer, cx| {
3045                            callback(observer, released, cx);
3046                        });
3047                    }
3048                });
3049            })
3050    }
3051
3052    pub fn observe_actions<F>(&mut self, mut callback: F) -> Subscription
3053    where
3054        F: 'static + FnMut(&mut V, TypeId, &mut ViewContext<V>),
3055    {
3056        let window_id = self.window_id;
3057        let observer = self.weak_handle();
3058        self.window_context.observe_actions(move |action_id, cx| {
3059            cx.update_window(window_id, |cx| {
3060                if let Some(observer) = observer.upgrade(cx) {
3061                    observer.update(cx, |observer, cx| {
3062                        callback(observer, action_id, cx);
3063                    });
3064                }
3065            });
3066        })
3067    }
3068
3069    pub fn observe_window_activation<F>(&mut self, mut callback: F) -> Subscription
3070    where
3071        F: 'static + FnMut(&mut V, bool, &mut ViewContext<V>),
3072    {
3073        let observer = self.weak_handle();
3074        self.window_context
3075            .observe_window_activation(move |active, cx| {
3076                if let Some(observer) = observer.upgrade(cx) {
3077                    observer.update(cx, |observer, cx| {
3078                        callback(observer, active, cx);
3079                    });
3080                    true
3081                } else {
3082                    false
3083                }
3084            })
3085    }
3086
3087    pub fn observe_fullscreen<F>(&mut self, mut callback: F) -> Subscription
3088    where
3089        F: 'static + FnMut(&mut V, bool, &mut ViewContext<V>),
3090    {
3091        let observer = self.weak_handle();
3092        self.window_context.observe_fullscreen(move |active, cx| {
3093            if let Some(observer) = observer.upgrade(cx) {
3094                observer.update(cx, |observer, cx| {
3095                    callback(observer, active, cx);
3096                });
3097                true
3098            } else {
3099                false
3100            }
3101        })
3102    }
3103
3104    pub fn observe_keystrokes<F>(&mut self, mut callback: F) -> Subscription
3105    where
3106        F: 'static
3107            + FnMut(
3108                &mut V,
3109                &Keystroke,
3110                Option<&Box<dyn Action>>,
3111                &MatchResult,
3112                &mut ViewContext<V>,
3113            ) -> bool,
3114    {
3115        let observer = self.weak_handle();
3116        self.window_context
3117            .observe_keystrokes(move |keystroke, result, handled_by, cx| {
3118                if let Some(observer) = observer.upgrade(cx) {
3119                    observer.update(cx, |observer, cx| {
3120                        callback(observer, keystroke, handled_by, result, cx);
3121                    });
3122                    true
3123                } else {
3124                    false
3125                }
3126            })
3127    }
3128
3129    pub fn observe_window_bounds<F>(&mut self, mut callback: F) -> Subscription
3130    where
3131        F: 'static + FnMut(&mut V, WindowBounds, Uuid, &mut ViewContext<V>),
3132    {
3133        let observer = self.weak_handle();
3134        self.window_context
3135            .observe_window_bounds(move |bounds, display, cx| {
3136                if let Some(observer) = observer.upgrade(cx) {
3137                    observer.update(cx, |observer, cx| {
3138                        callback(observer, bounds, display, cx);
3139                    });
3140                    true
3141                } else {
3142                    false
3143                }
3144            })
3145    }
3146
3147    pub fn observe_active_labeled_tasks<F>(&mut self, mut callback: F) -> Subscription
3148    where
3149        F: 'static + FnMut(&mut V, &mut ViewContext<V>),
3150    {
3151        let window_id = self.window_id;
3152        let observer = self.weak_handle();
3153        self.window_context.observe_active_labeled_tasks(move |cx| {
3154            cx.update_window(window_id, |cx| {
3155                if let Some(observer) = observer.upgrade(cx) {
3156                    observer.update(cx, |observer, cx| {
3157                        callback(observer, cx);
3158                    });
3159                    true
3160                } else {
3161                    false
3162                }
3163            })
3164            .unwrap_or(false)
3165        })
3166    }
3167
3168    pub fn emit(&mut self, payload: V::Event) {
3169        self.window_context
3170            .pending_effects
3171            .push_back(Effect::Event {
3172                entity_id: self.view_id,
3173                payload: Box::new(payload),
3174            });
3175    }
3176
3177    pub fn notify(&mut self) {
3178        let window_id = self.window_id;
3179        let view_id = self.view_id;
3180        self.window_context.notify_view(window_id, view_id);
3181    }
3182
3183    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut V, &mut ViewContext<V>)) {
3184        let handle = self.handle();
3185        self.window_context
3186            .defer(move |cx| handle.update(cx, |view, cx| callback(view, cx)))
3187    }
3188
3189    pub fn after_window_update(
3190        &mut self,
3191        callback: impl 'static + FnOnce(&mut V, &mut ViewContext<V>),
3192    ) {
3193        let window_id = self.window_id;
3194        let handle = self.handle();
3195        self.window_context.after_window_update(move |cx| {
3196            cx.update_window(window_id, |cx| {
3197                handle.update(cx, |view, cx| {
3198                    callback(view, cx);
3199                })
3200            });
3201        })
3202    }
3203
3204    pub fn propagate_action(&mut self) {
3205        self.window_context.halt_action_dispatch = false;
3206    }
3207
3208    pub fn spawn_labeled<F, Fut, S>(&mut self, task_label: &'static str, f: F) -> Task<S>
3209    where
3210        F: FnOnce(WeakViewHandle<V>, AsyncAppContext) -> Fut,
3211        Fut: 'static + Future<Output = S>,
3212        S: 'static,
3213    {
3214        let handle = self.weak_handle();
3215        self.window_context
3216            .spawn_labeled(task_label, |cx| f(handle, cx))
3217    }
3218
3219    pub fn spawn<F, Fut, S>(&mut self, f: F) -> Task<S>
3220    where
3221        F: FnOnce(WeakViewHandle<V>, AsyncAppContext) -> Fut,
3222        Fut: 'static + Future<Output = S>,
3223        S: 'static,
3224    {
3225        let handle = self.weak_handle();
3226        self.window_context.spawn(|cx| f(handle, cx))
3227    }
3228
3229    pub fn mouse_state<Tag: 'static>(&self, region_id: usize) -> MouseState {
3230        let region_id = MouseRegionId::new::<Tag>(self.view_id, region_id);
3231        MouseState {
3232            hovered: self.window.hovered_region_ids.contains(&region_id),
3233            clicked: self
3234                .window
3235                .clicked_region_ids
3236                .get(&region_id)
3237                .and_then(|_| self.window.clicked_button),
3238            accessed_hovered: false,
3239            accessed_clicked: false,
3240        }
3241    }
3242
3243    pub fn element_state<Tag: 'static, T: 'static>(
3244        &mut self,
3245        element_id: usize,
3246        initial: T,
3247    ) -> ElementStateHandle<T> {
3248        let id = ElementStateId {
3249            view_id: self.view_id(),
3250            element_id,
3251            tag: TypeId::of::<Tag>(),
3252        };
3253        self.element_states
3254            .entry(id)
3255            .or_insert_with(|| Box::new(initial));
3256        ElementStateHandle::new(id, self.frame_count, &self.ref_counts)
3257    }
3258
3259    pub fn default_element_state<Tag: 'static, T: 'static + Default>(
3260        &mut self,
3261        element_id: usize,
3262    ) -> ElementStateHandle<T> {
3263        self.element_state::<Tag, T>(element_id, T::default())
3264    }
3265}
3266
3267impl<V> BorrowAppContext for ViewContext<'_, '_, V> {
3268    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
3269        BorrowAppContext::read_with(&*self.window_context, f)
3270    }
3271
3272    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
3273        BorrowAppContext::update(&mut *self.window_context, f)
3274    }
3275}
3276
3277impl<V> BorrowWindowContext for ViewContext<'_, '_, V> {
3278    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T {
3279        BorrowWindowContext::read_with(&*self.window_context, window_id, f)
3280    }
3281
3282    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T {
3283        BorrowWindowContext::update(&mut *self.window_context, window_id, f)
3284    }
3285}
3286
3287pub struct LayoutContext<'a, 'b, 'c, V: View> {
3288    view_context: &'c mut ViewContext<'a, 'b, V>,
3289    new_parents: &'c mut HashMap<usize, usize>,
3290    views_to_notify_if_ancestors_change: &'c mut HashMap<usize, SmallVec<[usize; 2]>>,
3291    pub refreshing: bool,
3292}
3293
3294impl<'a, 'b, 'c, V: View> LayoutContext<'a, 'b, 'c, V> {
3295    pub fn new(
3296        view_context: &'c mut ViewContext<'a, 'b, V>,
3297        new_parents: &'c mut HashMap<usize, usize>,
3298        views_to_notify_if_ancestors_change: &'c mut HashMap<usize, SmallVec<[usize; 2]>>,
3299        refreshing: bool,
3300    ) -> Self {
3301        Self {
3302            view_context,
3303            new_parents,
3304            views_to_notify_if_ancestors_change,
3305            refreshing,
3306        }
3307    }
3308
3309    pub fn view_context(&mut self) -> &mut ViewContext<'a, 'b, V> {
3310        self.view_context
3311    }
3312
3313    /// Return keystrokes that would dispatch the given action on the given view.
3314    pub(crate) fn keystrokes_for_action(
3315        &mut self,
3316        view_id: usize,
3317        action: &dyn Action,
3318    ) -> Option<SmallVec<[Keystroke; 2]>> {
3319        self.notify_if_view_ancestors_change(view_id);
3320
3321        let window_id = self.window_id;
3322        let mut contexts = Vec::new();
3323        let mut handler_depth = None;
3324        for (i, view_id) in self.ancestors(view_id).enumerate() {
3325            if let Some(view_metadata) = self.views_metadata.get(&(window_id, view_id)) {
3326                if let Some(actions) = self.actions.get(&view_metadata.type_id) {
3327                    if actions.contains_key(&action.as_any().type_id()) {
3328                        handler_depth = Some(i);
3329                    }
3330                }
3331                contexts.push(view_metadata.keymap_context.clone());
3332            }
3333        }
3334
3335        if self.global_actions.contains_key(&action.as_any().type_id()) {
3336            handler_depth = Some(contexts.len())
3337        }
3338
3339        self.keystroke_matcher
3340            .bindings_for_action_type(action.as_any().type_id())
3341            .find_map(|b| {
3342                handler_depth
3343                    .map(|highest_handler| {
3344                        if (0..=highest_handler).any(|depth| b.match_context(&contexts[depth..])) {
3345                            Some(b.keystrokes().into())
3346                        } else {
3347                            None
3348                        }
3349                    })
3350                    .flatten()
3351            })
3352    }
3353
3354    fn notify_if_view_ancestors_change(&mut self, view_id: usize) {
3355        let self_view_id = self.view_id;
3356        self.views_to_notify_if_ancestors_change
3357            .entry(view_id)
3358            .or_default()
3359            .push(self_view_id);
3360    }
3361}
3362
3363impl<'a, 'b, 'c, V: View> Deref for LayoutContext<'a, 'b, 'c, V> {
3364    type Target = ViewContext<'a, 'b, V>;
3365
3366    fn deref(&self) -> &Self::Target {
3367        &self.view_context
3368    }
3369}
3370
3371impl<V: View> DerefMut for LayoutContext<'_, '_, '_, V> {
3372    fn deref_mut(&mut self) -> &mut Self::Target {
3373        &mut self.view_context
3374    }
3375}
3376
3377impl<V: View> BorrowAppContext for LayoutContext<'_, '_, '_, V> {
3378    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
3379        BorrowAppContext::read_with(&*self.view_context, f)
3380    }
3381
3382    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
3383        BorrowAppContext::update(&mut *self.view_context, f)
3384    }
3385}
3386
3387impl<V: View> BorrowWindowContext for LayoutContext<'_, '_, '_, V> {
3388    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T {
3389        BorrowWindowContext::read_with(&*self.view_context, window_id, f)
3390    }
3391
3392    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T {
3393        BorrowWindowContext::update(&mut *self.view_context, window_id, f)
3394    }
3395}
3396
3397pub struct EventContext<'a, 'b, 'c, V: View> {
3398    view_context: &'c mut ViewContext<'a, 'b, V>,
3399    pub(crate) handled: bool,
3400}
3401
3402impl<'a, 'b, 'c, V: View> EventContext<'a, 'b, 'c, V> {
3403    pub(crate) fn new(view_context: &'c mut ViewContext<'a, 'b, V>) -> Self {
3404        EventContext {
3405            view_context,
3406            handled: true,
3407        }
3408    }
3409
3410    pub fn propagate_event(&mut self) {
3411        self.handled = false;
3412    }
3413}
3414
3415impl<'a, 'b, 'c, V: View> Deref for EventContext<'a, 'b, 'c, V> {
3416    type Target = ViewContext<'a, 'b, V>;
3417
3418    fn deref(&self) -> &Self::Target {
3419        &self.view_context
3420    }
3421}
3422
3423impl<V: View> DerefMut for EventContext<'_, '_, '_, V> {
3424    fn deref_mut(&mut self) -> &mut Self::Target {
3425        &mut self.view_context
3426    }
3427}
3428
3429impl<V: View> BorrowAppContext for EventContext<'_, '_, '_, V> {
3430    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
3431        BorrowAppContext::read_with(&*self.view_context, f)
3432    }
3433
3434    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
3435        BorrowAppContext::update(&mut *self.view_context, f)
3436    }
3437}
3438
3439impl<V: View> BorrowWindowContext for EventContext<'_, '_, '_, V> {
3440    fn read_with<T, F: FnOnce(&WindowContext) -> T>(&self, window_id: usize, f: F) -> T {
3441        BorrowWindowContext::read_with(&*self.view_context, window_id, f)
3442    }
3443
3444    fn update<T, F: FnOnce(&mut WindowContext) -> T>(&mut self, window_id: usize, f: F) -> T {
3445        BorrowWindowContext::update(&mut *self.view_context, window_id, f)
3446    }
3447}
3448
3449pub(crate) enum Reference<'a, T> {
3450    Immutable(&'a T),
3451    Mutable(&'a mut T),
3452}
3453
3454impl<'a, T> Deref for Reference<'a, T> {
3455    type Target = T;
3456
3457    fn deref(&self) -> &Self::Target {
3458        match self {
3459            Reference::Immutable(target) => target,
3460            Reference::Mutable(target) => target,
3461        }
3462    }
3463}
3464
3465impl<'a, T> DerefMut for Reference<'a, T> {
3466    fn deref_mut(&mut self) -> &mut Self::Target {
3467        match self {
3468            Reference::Immutable(_) => {
3469                panic!("cannot mutably deref an immutable reference. this is a bug in GPUI.");
3470            }
3471            Reference::Mutable(target) => target,
3472        }
3473    }
3474}
3475
3476#[derive(Debug, Clone, Default)]
3477pub struct MouseState {
3478    pub(crate) hovered: bool,
3479    pub(crate) clicked: Option<MouseButton>,
3480    pub(crate) accessed_hovered: bool,
3481    pub(crate) accessed_clicked: bool,
3482}
3483
3484impl MouseState {
3485    pub fn hovered(&mut self) -> bool {
3486        self.accessed_hovered = true;
3487        self.hovered
3488    }
3489
3490    pub fn clicked(&mut self) -> Option<MouseButton> {
3491        self.accessed_clicked = true;
3492        self.clicked
3493    }
3494
3495    pub fn accessed_hovered(&self) -> bool {
3496        self.accessed_hovered
3497    }
3498
3499    pub fn accessed_clicked(&self) -> bool {
3500        self.accessed_clicked
3501    }
3502}
3503
3504pub trait Handle<T> {
3505    type Weak: 'static;
3506    fn id(&self) -> usize;
3507    fn location(&self) -> EntityLocation;
3508    fn downgrade(&self) -> Self::Weak;
3509    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
3510    where
3511        Self: Sized;
3512}
3513
3514pub trait WeakHandle {
3515    fn id(&self) -> usize;
3516}
3517
3518#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
3519pub enum EntityLocation {
3520    Model(usize),
3521    View(usize, usize),
3522}
3523
3524pub struct ModelHandle<T: Entity> {
3525    any_handle: AnyModelHandle,
3526    model_type: PhantomData<T>,
3527}
3528
3529impl<T: Entity> Deref for ModelHandle<T> {
3530    type Target = AnyModelHandle;
3531
3532    fn deref(&self) -> &Self::Target {
3533        &self.any_handle
3534    }
3535}
3536
3537impl<T: Entity> ModelHandle<T> {
3538    fn new(model_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
3539        Self {
3540            any_handle: AnyModelHandle::new(model_id, TypeId::of::<T>(), ref_counts.clone()),
3541            model_type: PhantomData,
3542        }
3543    }
3544
3545    pub fn downgrade(&self) -> WeakModelHandle<T> {
3546        WeakModelHandle::new(self.model_id)
3547    }
3548
3549    pub fn id(&self) -> usize {
3550        self.model_id
3551    }
3552
3553    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
3554        cx.read_model(self)
3555    }
3556
3557    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
3558    where
3559        C: BorrowAppContext,
3560        F: FnOnce(&T, &AppContext) -> S,
3561    {
3562        cx.read_with(|cx| read(self.read(cx), cx))
3563    }
3564
3565    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
3566    where
3567        C: BorrowAppContext,
3568        F: FnOnce(&mut T, &mut ModelContext<T>) -> S,
3569    {
3570        let mut update = Some(update);
3571        cx.update(|cx| {
3572            cx.update_model(self, &mut |model, cx| {
3573                let update = update.take().unwrap();
3574                update(model, cx)
3575            })
3576        })
3577    }
3578}
3579
3580impl<T: Entity> Clone for ModelHandle<T> {
3581    fn clone(&self) -> Self {
3582        Self::new(self.model_id, &self.ref_counts)
3583    }
3584}
3585
3586impl<T: Entity> PartialEq for ModelHandle<T> {
3587    fn eq(&self, other: &Self) -> bool {
3588        self.model_id == other.model_id
3589    }
3590}
3591
3592impl<T: Entity> Eq for ModelHandle<T> {}
3593
3594impl<T: Entity> PartialEq<WeakModelHandle<T>> for ModelHandle<T> {
3595    fn eq(&self, other: &WeakModelHandle<T>) -> bool {
3596        self.model_id == other.model_id
3597    }
3598}
3599
3600impl<T: Entity> Hash for ModelHandle<T> {
3601    fn hash<H: Hasher>(&self, state: &mut H) {
3602        self.model_id.hash(state);
3603    }
3604}
3605
3606impl<T: Entity> std::borrow::Borrow<usize> for ModelHandle<T> {
3607    fn borrow(&self) -> &usize {
3608        &self.model_id
3609    }
3610}
3611
3612impl<T: Entity> Debug for ModelHandle<T> {
3613    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3614        f.debug_tuple(&format!("ModelHandle<{}>", type_name::<T>()))
3615            .field(&self.model_id)
3616            .finish()
3617    }
3618}
3619
3620unsafe impl<T: Entity> Send for ModelHandle<T> {}
3621unsafe impl<T: Entity> Sync for ModelHandle<T> {}
3622
3623impl<T: Entity> Handle<T> for ModelHandle<T> {
3624    type Weak = WeakModelHandle<T>;
3625
3626    fn id(&self) -> usize {
3627        self.model_id
3628    }
3629
3630    fn location(&self) -> EntityLocation {
3631        EntityLocation::Model(self.model_id)
3632    }
3633
3634    fn downgrade(&self) -> Self::Weak {
3635        self.downgrade()
3636    }
3637
3638    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
3639    where
3640        Self: Sized,
3641    {
3642        weak.upgrade(cx)
3643    }
3644}
3645
3646pub struct WeakModelHandle<T> {
3647    any_handle: AnyWeakModelHandle,
3648    model_type: PhantomData<T>,
3649}
3650
3651impl<T> WeakModelHandle<T> {
3652    pub fn into_any(self) -> AnyWeakModelHandle {
3653        self.any_handle
3654    }
3655}
3656
3657impl<T> Deref for WeakModelHandle<T> {
3658    type Target = AnyWeakModelHandle;
3659
3660    fn deref(&self) -> &Self::Target {
3661        &self.any_handle
3662    }
3663}
3664
3665impl<T> WeakHandle for WeakModelHandle<T> {
3666    fn id(&self) -> usize {
3667        self.model_id
3668    }
3669}
3670
3671unsafe impl<T> Send for WeakModelHandle<T> {}
3672unsafe impl<T> Sync for WeakModelHandle<T> {}
3673
3674impl<T: Entity> WeakModelHandle<T> {
3675    fn new(model_id: usize) -> Self {
3676        Self {
3677            any_handle: AnyWeakModelHandle {
3678                model_id,
3679                model_type: TypeId::of::<T>(),
3680            },
3681            model_type: PhantomData,
3682        }
3683    }
3684
3685    pub fn id(&self) -> usize {
3686        self.model_id
3687    }
3688
3689    pub fn is_upgradable(&self, cx: &impl BorrowAppContext) -> bool {
3690        cx.read_with(|cx| cx.model_handle_is_upgradable(self))
3691    }
3692
3693    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<ModelHandle<T>> {
3694        cx.read_with(|cx| cx.upgrade_model_handle(self))
3695    }
3696}
3697
3698impl<T> Hash for WeakModelHandle<T> {
3699    fn hash<H: Hasher>(&self, state: &mut H) {
3700        self.model_id.hash(state)
3701    }
3702}
3703
3704impl<T> PartialEq for WeakModelHandle<T> {
3705    fn eq(&self, other: &Self) -> bool {
3706        self.model_id == other.model_id
3707    }
3708}
3709
3710impl<T> Eq for WeakModelHandle<T> {}
3711
3712impl<T: Entity> PartialEq<ModelHandle<T>> for WeakModelHandle<T> {
3713    fn eq(&self, other: &ModelHandle<T>) -> bool {
3714        self.model_id == other.model_id
3715    }
3716}
3717
3718impl<T> Clone for WeakModelHandle<T> {
3719    fn clone(&self) -> Self {
3720        Self {
3721            any_handle: self.any_handle.clone(),
3722            model_type: PhantomData,
3723        }
3724    }
3725}
3726
3727impl<T> Copy for WeakModelHandle<T> {}
3728
3729#[repr(transparent)]
3730pub struct ViewHandle<T> {
3731    any_handle: AnyViewHandle,
3732    view_type: PhantomData<T>,
3733}
3734
3735impl<T> Deref for ViewHandle<T> {
3736    type Target = AnyViewHandle;
3737
3738    fn deref(&self) -> &Self::Target {
3739        &self.any_handle
3740    }
3741}
3742
3743impl<T: View> ViewHandle<T> {
3744    fn new(window_id: usize, view_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
3745        Self {
3746            any_handle: AnyViewHandle::new(
3747                window_id,
3748                view_id,
3749                TypeId::of::<T>(),
3750                ref_counts.clone(),
3751            ),
3752            view_type: PhantomData,
3753        }
3754    }
3755
3756    pub fn downgrade(&self) -> WeakViewHandle<T> {
3757        WeakViewHandle::new(self.window_id, self.view_id)
3758    }
3759
3760    pub fn into_any(self) -> AnyViewHandle {
3761        self.any_handle
3762    }
3763
3764    pub fn window_id(&self) -> usize {
3765        self.window_id
3766    }
3767
3768    pub fn id(&self) -> usize {
3769        self.view_id
3770    }
3771
3772    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
3773        cx.read_view(self)
3774    }
3775
3776    pub fn read_with<C, F, S>(&self, cx: &C, read: F) -> S
3777    where
3778        C: BorrowWindowContext,
3779        F: FnOnce(&T, &ViewContext<T>) -> S,
3780    {
3781        cx.read_with(self.window_id, |cx| {
3782            let cx = ViewContext::immutable(cx, self.view_id);
3783            read(cx.read_view(self), &cx)
3784        })
3785    }
3786
3787    pub fn update<C, F, S>(&self, cx: &mut C, update: F) -> S
3788    where
3789        C: BorrowWindowContext,
3790        F: FnOnce(&mut T, &mut ViewContext<T>) -> S,
3791    {
3792        let mut update = Some(update);
3793
3794        cx.update(self.window_id, |cx| {
3795            cx.update_view(self, &mut |view, cx| {
3796                let update = update.take().unwrap();
3797                update(view, cx)
3798            })
3799        })
3800    }
3801
3802    pub fn is_focused(&self, cx: &WindowContext) -> bool {
3803        cx.focused_view_id() == Some(self.view_id)
3804    }
3805}
3806
3807impl<T: View> Clone for ViewHandle<T> {
3808    fn clone(&self) -> Self {
3809        ViewHandle::new(self.window_id, self.view_id, &self.ref_counts)
3810    }
3811}
3812
3813impl<T> PartialEq for ViewHandle<T> {
3814    fn eq(&self, other: &Self) -> bool {
3815        self.window_id == other.window_id && self.view_id == other.view_id
3816    }
3817}
3818
3819impl<T> PartialEq<WeakViewHandle<T>> for ViewHandle<T> {
3820    fn eq(&self, other: &WeakViewHandle<T>) -> bool {
3821        self.window_id == other.window_id && self.view_id == other.view_id
3822    }
3823}
3824
3825impl<T> PartialEq<ViewHandle<T>> for WeakViewHandle<T> {
3826    fn eq(&self, other: &ViewHandle<T>) -> bool {
3827        self.window_id == other.window_id && self.view_id == other.view_id
3828    }
3829}
3830
3831impl<T> Eq for ViewHandle<T> {}
3832
3833impl<T> Hash for ViewHandle<T> {
3834    fn hash<H: Hasher>(&self, state: &mut H) {
3835        self.window_id.hash(state);
3836        self.view_id.hash(state);
3837    }
3838}
3839
3840impl<T> Debug for ViewHandle<T> {
3841    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3842        f.debug_struct(&format!("ViewHandle<{}>", type_name::<T>()))
3843            .field("window_id", &self.window_id)
3844            .field("view_id", &self.view_id)
3845            .finish()
3846    }
3847}
3848
3849impl<T: View> Handle<T> for ViewHandle<T> {
3850    type Weak = WeakViewHandle<T>;
3851
3852    fn id(&self) -> usize {
3853        self.view_id
3854    }
3855
3856    fn location(&self) -> EntityLocation {
3857        EntityLocation::View(self.window_id, self.view_id)
3858    }
3859
3860    fn downgrade(&self) -> Self::Weak {
3861        self.downgrade()
3862    }
3863
3864    fn upgrade_from(weak: &Self::Weak, cx: &AppContext) -> Option<Self>
3865    where
3866        Self: Sized,
3867    {
3868        weak.upgrade(cx)
3869    }
3870}
3871
3872pub struct AnyViewHandle {
3873    window_id: usize,
3874    view_id: usize,
3875    view_type: TypeId,
3876    ref_counts: Arc<Mutex<RefCounts>>,
3877
3878    #[cfg(any(test, feature = "test-support"))]
3879    handle_id: usize,
3880}
3881
3882impl AnyViewHandle {
3883    fn new(
3884        window_id: usize,
3885        view_id: usize,
3886        view_type: TypeId,
3887        ref_counts: Arc<Mutex<RefCounts>>,
3888    ) -> Self {
3889        ref_counts.lock().inc_view(window_id, view_id);
3890
3891        #[cfg(any(test, feature = "test-support"))]
3892        let handle_id = ref_counts
3893            .lock()
3894            .leak_detector
3895            .lock()
3896            .handle_created(None, view_id);
3897
3898        Self {
3899            window_id,
3900            view_id,
3901            view_type,
3902            ref_counts,
3903            #[cfg(any(test, feature = "test-support"))]
3904            handle_id,
3905        }
3906    }
3907
3908    pub fn window_id(&self) -> usize {
3909        self.window_id
3910    }
3911
3912    pub fn id(&self) -> usize {
3913        self.view_id
3914    }
3915
3916    pub fn is<T: 'static>(&self) -> bool {
3917        TypeId::of::<T>() == self.view_type
3918    }
3919
3920    pub fn downcast<T: View>(self) -> Option<ViewHandle<T>> {
3921        if self.is::<T>() {
3922            Some(ViewHandle {
3923                any_handle: self,
3924                view_type: PhantomData,
3925            })
3926        } else {
3927            None
3928        }
3929    }
3930
3931    pub fn downcast_ref<T: View>(&self) -> Option<&ViewHandle<T>> {
3932        if self.is::<T>() {
3933            Some(unsafe { mem::transmute(self) })
3934        } else {
3935            None
3936        }
3937    }
3938
3939    pub fn downgrade(&self) -> AnyWeakViewHandle {
3940        AnyWeakViewHandle {
3941            window_id: self.window_id,
3942            view_id: self.view_id,
3943            view_type: self.view_type,
3944        }
3945    }
3946
3947    pub fn view_type(&self) -> TypeId {
3948        self.view_type
3949    }
3950
3951    pub fn debug_json<'a, 'b>(&self, cx: &'b WindowContext<'a>) -> serde_json::Value {
3952        cx.views
3953            .get(&(self.window_id, self.view_id))
3954            .map_or_else(|| serde_json::Value::Null, |view| view.debug_json(cx))
3955    }
3956}
3957
3958impl Clone for AnyViewHandle {
3959    fn clone(&self) -> Self {
3960        Self::new(
3961            self.window_id,
3962            self.view_id,
3963            self.view_type,
3964            self.ref_counts.clone(),
3965        )
3966    }
3967}
3968
3969impl<T> PartialEq<ViewHandle<T>> for AnyViewHandle {
3970    fn eq(&self, other: &ViewHandle<T>) -> bool {
3971        self.window_id == other.window_id && self.view_id == other.view_id
3972    }
3973}
3974
3975impl Drop for AnyViewHandle {
3976    fn drop(&mut self) {
3977        self.ref_counts
3978            .lock()
3979            .dec_view(self.window_id, self.view_id);
3980        #[cfg(any(test, feature = "test-support"))]
3981        self.ref_counts
3982            .lock()
3983            .leak_detector
3984            .lock()
3985            .handle_dropped(self.view_id, self.handle_id);
3986    }
3987}
3988
3989impl Debug for AnyViewHandle {
3990    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3991        f.debug_struct("AnyViewHandle")
3992            .field("window_id", &self.window_id)
3993            .field("view_id", &self.view_id)
3994            .finish()
3995    }
3996}
3997
3998pub struct AnyModelHandle {
3999    model_id: usize,
4000    model_type: TypeId,
4001    ref_counts: Arc<Mutex<RefCounts>>,
4002
4003    #[cfg(any(test, feature = "test-support"))]
4004    handle_id: usize,
4005}
4006
4007impl AnyModelHandle {
4008    fn new(model_id: usize, model_type: TypeId, ref_counts: Arc<Mutex<RefCounts>>) -> Self {
4009        ref_counts.lock().inc_model(model_id);
4010
4011        #[cfg(any(test, feature = "test-support"))]
4012        let handle_id = ref_counts
4013            .lock()
4014            .leak_detector
4015            .lock()
4016            .handle_created(None, model_id);
4017
4018        Self {
4019            model_id,
4020            model_type,
4021            ref_counts,
4022
4023            #[cfg(any(test, feature = "test-support"))]
4024            handle_id,
4025        }
4026    }
4027
4028    pub fn downcast<T: Entity>(self) -> Option<ModelHandle<T>> {
4029        if self.is::<T>() {
4030            Some(ModelHandle {
4031                any_handle: self,
4032                model_type: PhantomData,
4033            })
4034        } else {
4035            None
4036        }
4037    }
4038
4039    pub fn downgrade(&self) -> AnyWeakModelHandle {
4040        AnyWeakModelHandle {
4041            model_id: self.model_id,
4042            model_type: self.model_type,
4043        }
4044    }
4045
4046    pub fn is<T: Entity>(&self) -> bool {
4047        self.model_type == TypeId::of::<T>()
4048    }
4049
4050    pub fn model_type(&self) -> TypeId {
4051        self.model_type
4052    }
4053}
4054
4055impl Clone for AnyModelHandle {
4056    fn clone(&self) -> Self {
4057        Self::new(self.model_id, self.model_type, self.ref_counts.clone())
4058    }
4059}
4060
4061impl Drop for AnyModelHandle {
4062    fn drop(&mut self) {
4063        let mut ref_counts = self.ref_counts.lock();
4064        ref_counts.dec_model(self.model_id);
4065
4066        #[cfg(any(test, feature = "test-support"))]
4067        ref_counts
4068            .leak_detector
4069            .lock()
4070            .handle_dropped(self.model_id, self.handle_id);
4071    }
4072}
4073
4074#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy)]
4075pub struct AnyWeakModelHandle {
4076    model_id: usize,
4077    model_type: TypeId,
4078}
4079
4080impl AnyWeakModelHandle {
4081    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<AnyModelHandle> {
4082        cx.read_with(|cx| cx.upgrade_any_model_handle(self))
4083    }
4084
4085    pub fn model_type(&self) -> TypeId {
4086        self.model_type
4087    }
4088
4089    fn is<T: 'static>(&self) -> bool {
4090        TypeId::of::<T>() == self.model_type
4091    }
4092
4093    pub fn downcast<T: Entity>(self) -> Option<WeakModelHandle<T>> {
4094        if self.is::<T>() {
4095            let result = Some(WeakModelHandle {
4096                any_handle: self,
4097                model_type: PhantomData,
4098            });
4099
4100            result
4101        } else {
4102            None
4103        }
4104    }
4105}
4106
4107#[derive(Copy)]
4108pub struct WeakViewHandle<T> {
4109    any_handle: AnyWeakViewHandle,
4110    view_type: PhantomData<T>,
4111}
4112
4113impl<T> Debug for WeakViewHandle<T> {
4114    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
4115        f.debug_struct(&format!("WeakViewHandle<{}>", type_name::<T>()))
4116            .field("any_handle", &self.any_handle)
4117            .finish()
4118    }
4119}
4120
4121impl<T> WeakHandle for WeakViewHandle<T> {
4122    fn id(&self) -> usize {
4123        self.view_id
4124    }
4125}
4126
4127impl<V: View> WeakViewHandle<V> {
4128    fn new(window_id: usize, view_id: usize) -> Self {
4129        Self {
4130            any_handle: AnyWeakViewHandle {
4131                window_id,
4132                view_id,
4133                view_type: TypeId::of::<V>(),
4134            },
4135            view_type: PhantomData,
4136        }
4137    }
4138
4139    pub fn id(&self) -> usize {
4140        self.view_id
4141    }
4142
4143    pub fn window_id(&self) -> usize {
4144        self.window_id
4145    }
4146
4147    pub fn into_any(self) -> AnyWeakViewHandle {
4148        self.any_handle
4149    }
4150
4151    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<ViewHandle<V>> {
4152        cx.read_with(|cx| cx.upgrade_view_handle(self))
4153    }
4154
4155    pub fn read_with<T>(
4156        &self,
4157        cx: &AsyncAppContext,
4158        read: impl FnOnce(&V, &ViewContext<V>) -> T,
4159    ) -> Result<T> {
4160        cx.read(|cx| {
4161            let handle = cx
4162                .upgrade_view_handle(self)
4163                .ok_or_else(|| anyhow!("view {} was dropped", V::ui_name()))?;
4164            cx.read_window(self.window_id, |cx| handle.read_with(cx, read))
4165                .ok_or_else(|| anyhow!("window was removed"))
4166        })
4167    }
4168
4169    pub fn update<T>(
4170        &self,
4171        cx: &mut AsyncAppContext,
4172        update: impl FnOnce(&mut V, &mut ViewContext<V>) -> T,
4173    ) -> Result<T> {
4174        cx.update(|cx| {
4175            let handle = cx
4176                .upgrade_view_handle(self)
4177                .ok_or_else(|| anyhow!("view {} was dropped", V::ui_name()))?;
4178            cx.update_window(self.window_id, |cx| handle.update(cx, update))
4179                .ok_or_else(|| anyhow!("window was removed"))
4180        })
4181    }
4182}
4183
4184impl<T> Deref for WeakViewHandle<T> {
4185    type Target = AnyWeakViewHandle;
4186
4187    fn deref(&self) -> &Self::Target {
4188        &self.any_handle
4189    }
4190}
4191
4192impl<T> Clone for WeakViewHandle<T> {
4193    fn clone(&self) -> Self {
4194        Self {
4195            any_handle: self.any_handle.clone(),
4196            view_type: PhantomData,
4197        }
4198    }
4199}
4200
4201impl<T> PartialEq for WeakViewHandle<T> {
4202    fn eq(&self, other: &Self) -> bool {
4203        self.window_id == other.window_id && self.view_id == other.view_id
4204    }
4205}
4206
4207impl<T> Eq for WeakViewHandle<T> {}
4208
4209impl<T> Hash for WeakViewHandle<T> {
4210    fn hash<H: Hasher>(&self, state: &mut H) {
4211        self.any_handle.hash(state);
4212    }
4213}
4214
4215#[derive(Debug, Clone, Copy)]
4216pub struct AnyWeakViewHandle {
4217    window_id: usize,
4218    view_id: usize,
4219    view_type: TypeId,
4220}
4221
4222impl AnyWeakViewHandle {
4223    pub fn id(&self) -> usize {
4224        self.view_id
4225    }
4226
4227    fn is<T: 'static>(&self) -> bool {
4228        TypeId::of::<T>() == self.view_type
4229    }
4230
4231    pub fn upgrade(&self, cx: &impl BorrowAppContext) -> Option<AnyViewHandle> {
4232        cx.read_with(|cx| cx.upgrade_any_view_handle(self))
4233    }
4234
4235    pub fn downcast<T: View>(self) -> Option<WeakViewHandle<T>> {
4236        if self.is::<T>() {
4237            Some(WeakViewHandle {
4238                any_handle: self,
4239                view_type: PhantomData,
4240            })
4241        } else {
4242            None
4243        }
4244    }
4245}
4246
4247impl Hash for AnyWeakViewHandle {
4248    fn hash<H: Hasher>(&self, state: &mut H) {
4249        self.window_id.hash(state);
4250        self.view_id.hash(state);
4251        self.view_type.hash(state);
4252    }
4253}
4254
4255#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
4256pub struct ElementStateId {
4257    view_id: usize,
4258    element_id: usize,
4259    tag: TypeId,
4260}
4261
4262pub struct ElementStateHandle<T> {
4263    value_type: PhantomData<T>,
4264    id: ElementStateId,
4265    ref_counts: Weak<Mutex<RefCounts>>,
4266}
4267
4268impl<T: 'static> ElementStateHandle<T> {
4269    fn new(id: ElementStateId, frame_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
4270        ref_counts.lock().inc_element_state(id, frame_id);
4271        Self {
4272            value_type: PhantomData,
4273            id,
4274            ref_counts: Arc::downgrade(ref_counts),
4275        }
4276    }
4277
4278    pub fn id(&self) -> ElementStateId {
4279        self.id
4280    }
4281
4282    pub fn read<'a>(&self, cx: &'a AppContext) -> &'a T {
4283        cx.element_states
4284            .get(&self.id)
4285            .unwrap()
4286            .downcast_ref()
4287            .unwrap()
4288    }
4289
4290    pub fn update<C, D, R>(&self, cx: &mut C, f: impl FnOnce(&mut T, &mut C) -> R) -> R
4291    where
4292        C: DerefMut<Target = D>,
4293        D: DerefMut<Target = AppContext>,
4294    {
4295        let mut element_state = cx.deref_mut().element_states.remove(&self.id).unwrap();
4296        let result = f(element_state.downcast_mut().unwrap(), cx);
4297        cx.deref_mut().element_states.insert(self.id, element_state);
4298        result
4299    }
4300}
4301
4302impl<T> Drop for ElementStateHandle<T> {
4303    fn drop(&mut self) {
4304        if let Some(ref_counts) = self.ref_counts.upgrade() {
4305            ref_counts.lock().dec_element_state(self.id);
4306        }
4307    }
4308}
4309
4310#[must_use]
4311pub enum Subscription {
4312    Subscription(callback_collection::Subscription<usize, SubscriptionCallback>),
4313    Observation(callback_collection::Subscription<usize, ObservationCallback>),
4314    GlobalSubscription(callback_collection::Subscription<TypeId, GlobalSubscriptionCallback>),
4315    GlobalObservation(callback_collection::Subscription<TypeId, GlobalObservationCallback>),
4316    FocusObservation(callback_collection::Subscription<usize, FocusObservationCallback>),
4317    WindowActivationObservation(callback_collection::Subscription<usize, WindowActivationCallback>),
4318    WindowFullscreenObservation(callback_collection::Subscription<usize, WindowFullscreenCallback>),
4319    WindowBoundsObservation(callback_collection::Subscription<usize, WindowBoundsCallback>),
4320    KeystrokeObservation(callback_collection::Subscription<usize, KeystrokeCallback>),
4321    ReleaseObservation(callback_collection::Subscription<usize, ReleaseObservationCallback>),
4322    ActionObservation(callback_collection::Subscription<(), ActionObservationCallback>),
4323    ActiveLabeledTasksObservation(
4324        callback_collection::Subscription<(), ActiveLabeledTasksCallback>,
4325    ),
4326}
4327
4328impl Subscription {
4329    pub fn id(&self) -> usize {
4330        match self {
4331            Subscription::Subscription(subscription) => subscription.id(),
4332            Subscription::Observation(subscription) => subscription.id(),
4333            Subscription::GlobalSubscription(subscription) => subscription.id(),
4334            Subscription::GlobalObservation(subscription) => subscription.id(),
4335            Subscription::FocusObservation(subscription) => subscription.id(),
4336            Subscription::WindowActivationObservation(subscription) => subscription.id(),
4337            Subscription::WindowFullscreenObservation(subscription) => subscription.id(),
4338            Subscription::WindowBoundsObservation(subscription) => subscription.id(),
4339            Subscription::KeystrokeObservation(subscription) => subscription.id(),
4340            Subscription::ReleaseObservation(subscription) => subscription.id(),
4341            Subscription::ActionObservation(subscription) => subscription.id(),
4342            Subscription::ActiveLabeledTasksObservation(subscription) => subscription.id(),
4343        }
4344    }
4345
4346    pub fn detach(&mut self) {
4347        match self {
4348            Subscription::Subscription(subscription) => subscription.detach(),
4349            Subscription::GlobalSubscription(subscription) => subscription.detach(),
4350            Subscription::Observation(subscription) => subscription.detach(),
4351            Subscription::GlobalObservation(subscription) => subscription.detach(),
4352            Subscription::FocusObservation(subscription) => subscription.detach(),
4353            Subscription::KeystrokeObservation(subscription) => subscription.detach(),
4354            Subscription::WindowActivationObservation(subscription) => subscription.detach(),
4355            Subscription::WindowFullscreenObservation(subscription) => subscription.detach(),
4356            Subscription::WindowBoundsObservation(subscription) => subscription.detach(),
4357            Subscription::ReleaseObservation(subscription) => subscription.detach(),
4358            Subscription::ActionObservation(subscription) => subscription.detach(),
4359            Subscription::ActiveLabeledTasksObservation(subscription) => subscription.detach(),
4360        }
4361    }
4362}
4363
4364#[cfg(test)]
4365mod tests {
4366    use super::*;
4367    use crate::{
4368        actions,
4369        elements::*,
4370        impl_actions,
4371        platform::{MouseButton, MouseButtonEvent},
4372        window::ChildView,
4373    };
4374    use itertools::Itertools;
4375    use postage::{sink::Sink, stream::Stream};
4376    use serde::Deserialize;
4377    use smol::future::poll_once;
4378    use std::{
4379        cell::Cell,
4380        sync::atomic::{AtomicBool, AtomicUsize, Ordering::SeqCst},
4381    };
4382
4383    #[crate::test(self)]
4384    fn test_model_handles(cx: &mut AppContext) {
4385        struct Model {
4386            other: Option<ModelHandle<Model>>,
4387            events: Vec<String>,
4388        }
4389
4390        impl Entity for Model {
4391            type Event = usize;
4392        }
4393
4394        impl Model {
4395            fn new(other: Option<ModelHandle<Self>>, cx: &mut ModelContext<Self>) -> Self {
4396                if let Some(other) = other.as_ref() {
4397                    cx.observe(other, |me, _, _| {
4398                        me.events.push("notified".into());
4399                    })
4400                    .detach();
4401                    cx.subscribe(other, |me, _, event, _| {
4402                        me.events.push(format!("observed event {}", event));
4403                    })
4404                    .detach();
4405                }
4406
4407                Self {
4408                    other,
4409                    events: Vec::new(),
4410                }
4411            }
4412        }
4413
4414        let handle_1 = cx.add_model(|cx| Model::new(None, cx));
4415        let handle_2 = cx.add_model(|cx| Model::new(Some(handle_1.clone()), cx));
4416        assert_eq!(cx.models.len(), 2);
4417
4418        handle_1.update(cx, |model, cx| {
4419            model.events.push("updated".into());
4420            cx.emit(1);
4421            cx.notify();
4422            cx.emit(2);
4423        });
4424        assert_eq!(handle_1.read(cx).events, vec!["updated".to_string()]);
4425        assert_eq!(
4426            handle_2.read(cx).events,
4427            vec![
4428                "observed event 1".to_string(),
4429                "notified".to_string(),
4430                "observed event 2".to_string(),
4431            ]
4432        );
4433
4434        handle_2.update(cx, |model, _| {
4435            drop(handle_1);
4436            model.other.take();
4437        });
4438
4439        assert_eq!(cx.models.len(), 1);
4440        assert!(cx.subscriptions.is_empty());
4441        assert!(cx.observations.is_empty());
4442    }
4443
4444    #[crate::test(self)]
4445    fn test_model_events(cx: &mut AppContext) {
4446        #[derive(Default)]
4447        struct Model {
4448            events: Vec<usize>,
4449        }
4450
4451        impl Entity for Model {
4452            type Event = usize;
4453        }
4454
4455        let handle_1 = cx.add_model(|_| Model::default());
4456        let handle_2 = cx.add_model(|_| Model::default());
4457
4458        handle_1.update(cx, |_, cx| {
4459            cx.subscribe(&handle_2, move |model: &mut Model, emitter, event, cx| {
4460                model.events.push(*event);
4461
4462                cx.subscribe(&emitter, |model, _, event, _| {
4463                    model.events.push(*event * 2);
4464                })
4465                .detach();
4466            })
4467            .detach();
4468        });
4469
4470        handle_2.update(cx, |_, c| c.emit(7));
4471        assert_eq!(handle_1.read(cx).events, vec![7]);
4472
4473        handle_2.update(cx, |_, c| c.emit(5));
4474        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10]);
4475    }
4476
4477    #[crate::test(self)]
4478    fn test_model_emit_before_subscribe_in_same_update_cycle(cx: &mut AppContext) {
4479        #[derive(Default)]
4480        struct Model;
4481
4482        impl Entity for Model {
4483            type Event = ();
4484        }
4485
4486        let events = Rc::new(RefCell::new(Vec::new()));
4487        cx.add_model(|cx| {
4488            drop(cx.subscribe(&cx.handle(), {
4489                let events = events.clone();
4490                move |_, _, _, _| events.borrow_mut().push("dropped before flush")
4491            }));
4492            cx.subscribe(&cx.handle(), {
4493                let events = events.clone();
4494                move |_, _, _, _| events.borrow_mut().push("before emit")
4495            })
4496            .detach();
4497            cx.emit(());
4498            cx.subscribe(&cx.handle(), {
4499                let events = events.clone();
4500                move |_, _, _, _| events.borrow_mut().push("after emit")
4501            })
4502            .detach();
4503            Model
4504        });
4505        assert_eq!(*events.borrow(), ["before emit"]);
4506    }
4507
4508    #[crate::test(self)]
4509    fn test_observe_and_notify_from_model(cx: &mut AppContext) {
4510        #[derive(Default)]
4511        struct Model {
4512            count: usize,
4513            events: Vec<usize>,
4514        }
4515
4516        impl Entity for Model {
4517            type Event = ();
4518        }
4519
4520        let handle_1 = cx.add_model(|_| Model::default());
4521        let handle_2 = cx.add_model(|_| Model::default());
4522
4523        handle_1.update(cx, |_, c| {
4524            c.observe(&handle_2, move |model, observed, c| {
4525                model.events.push(observed.read(c).count);
4526                c.observe(&observed, |model, observed, c| {
4527                    model.events.push(observed.read(c).count * 2);
4528                })
4529                .detach();
4530            })
4531            .detach();
4532        });
4533
4534        handle_2.update(cx, |model, c| {
4535            model.count = 7;
4536            c.notify()
4537        });
4538        assert_eq!(handle_1.read(cx).events, vec![7]);
4539
4540        handle_2.update(cx, |model, c| {
4541            model.count = 5;
4542            c.notify()
4543        });
4544        assert_eq!(handle_1.read(cx).events, vec![7, 5, 10])
4545    }
4546
4547    #[crate::test(self)]
4548    fn test_model_notify_before_observe_in_same_update_cycle(cx: &mut AppContext) {
4549        #[derive(Default)]
4550        struct Model;
4551
4552        impl Entity for Model {
4553            type Event = ();
4554        }
4555
4556        let events = Rc::new(RefCell::new(Vec::new()));
4557        cx.add_model(|cx| {
4558            drop(cx.observe(&cx.handle(), {
4559                let events = events.clone();
4560                move |_, _, _| events.borrow_mut().push("dropped before flush")
4561            }));
4562            cx.observe(&cx.handle(), {
4563                let events = events.clone();
4564                move |_, _, _| events.borrow_mut().push("before notify")
4565            })
4566            .detach();
4567            cx.notify();
4568            cx.observe(&cx.handle(), {
4569                let events = events.clone();
4570                move |_, _, _| events.borrow_mut().push("after notify")
4571            })
4572            .detach();
4573            Model
4574        });
4575        assert_eq!(*events.borrow(), ["before notify"]);
4576    }
4577
4578    #[crate::test(self)]
4579    fn test_defer_and_after_window_update(cx: &mut TestAppContext) {
4580        struct View {
4581            render_count: usize,
4582        }
4583
4584        impl Entity for View {
4585            type Event = usize;
4586        }
4587
4588        impl super::View for View {
4589            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
4590                post_inc(&mut self.render_count);
4591                Empty::new().into_any()
4592            }
4593
4594            fn ui_name() -> &'static str {
4595                "View"
4596            }
4597        }
4598
4599        let (_, view) = cx.add_window(|_| View { render_count: 0 });
4600        let called_defer = Rc::new(AtomicBool::new(false));
4601        let called_after_window_update = Rc::new(AtomicBool::new(false));
4602
4603        view.update(cx, |this, cx| {
4604            assert_eq!(this.render_count, 1);
4605            cx.defer({
4606                let called_defer = called_defer.clone();
4607                move |this, _| {
4608                    assert_eq!(this.render_count, 1);
4609                    called_defer.store(true, SeqCst);
4610                }
4611            });
4612            cx.after_window_update({
4613                let called_after_window_update = called_after_window_update.clone();
4614                move |this, cx| {
4615                    assert_eq!(this.render_count, 2);
4616                    called_after_window_update.store(true, SeqCst);
4617                    cx.notify();
4618                }
4619            });
4620            assert!(!called_defer.load(SeqCst));
4621            assert!(!called_after_window_update.load(SeqCst));
4622            cx.notify();
4623        });
4624
4625        assert!(called_defer.load(SeqCst));
4626        assert!(called_after_window_update.load(SeqCst));
4627        assert_eq!(view.read_with(cx, |view, _| view.render_count), 3);
4628    }
4629
4630    #[crate::test(self)]
4631    fn test_view_handles(cx: &mut TestAppContext) {
4632        struct View {
4633            other: Option<ViewHandle<View>>,
4634            events: Vec<String>,
4635        }
4636
4637        impl Entity for View {
4638            type Event = usize;
4639        }
4640
4641        impl super::View for View {
4642            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
4643                Empty::new().into_any()
4644            }
4645
4646            fn ui_name() -> &'static str {
4647                "View"
4648            }
4649        }
4650
4651        impl View {
4652            fn new(other: Option<ViewHandle<View>>, cx: &mut ViewContext<Self>) -> Self {
4653                if let Some(other) = other.as_ref() {
4654                    cx.subscribe(other, |me, _, event, _| {
4655                        me.events.push(format!("observed event {}", event));
4656                    })
4657                    .detach();
4658                }
4659                Self {
4660                    other,
4661                    events: Vec::new(),
4662                }
4663            }
4664        }
4665
4666        let (window_id, _root_view) = cx.add_window(|cx| View::new(None, cx));
4667        let handle_1 = cx.add_view(window_id, |cx| View::new(None, cx));
4668        let handle_2 = cx.add_view(window_id, |cx| View::new(Some(handle_1.clone()), cx));
4669        assert_eq!(cx.read(|cx| cx.views.len()), 3);
4670
4671        handle_1.update(cx, |view, cx| {
4672            view.events.push("updated".into());
4673            cx.emit(1);
4674            cx.emit(2);
4675        });
4676        handle_1.read_with(cx, |view, _| {
4677            assert_eq!(view.events, vec!["updated".to_string()]);
4678        });
4679        handle_2.read_with(cx, |view, _| {
4680            assert_eq!(
4681                view.events,
4682                vec![
4683                    "observed event 1".to_string(),
4684                    "observed event 2".to_string(),
4685                ]
4686            );
4687        });
4688
4689        handle_2.update(cx, |view, _| {
4690            drop(handle_1);
4691            view.other.take();
4692        });
4693
4694        cx.read(|cx| {
4695            assert_eq!(cx.views.len(), 2);
4696            assert!(cx.subscriptions.is_empty());
4697            assert!(cx.observations.is_empty());
4698        });
4699    }
4700
4701    #[crate::test(self)]
4702    fn test_add_window(cx: &mut AppContext) {
4703        struct View {
4704            mouse_down_count: Arc<AtomicUsize>,
4705        }
4706
4707        impl Entity for View {
4708            type Event = ();
4709        }
4710
4711        impl super::View for View {
4712            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
4713                enum Handler {}
4714                let mouse_down_count = self.mouse_down_count.clone();
4715                MouseEventHandler::<Handler, _>::new(0, cx, |_, _| Empty::new())
4716                    .on_down(MouseButton::Left, move |_, _, _| {
4717                        mouse_down_count.fetch_add(1, SeqCst);
4718                    })
4719                    .into_any()
4720            }
4721
4722            fn ui_name() -> &'static str {
4723                "View"
4724            }
4725        }
4726
4727        let mouse_down_count = Arc::new(AtomicUsize::new(0));
4728        let (window_id, _) = cx.add_window(Default::default(), |_| View {
4729            mouse_down_count: mouse_down_count.clone(),
4730        });
4731
4732        cx.update_window(window_id, |cx| {
4733            // Ensure window's root element is in a valid lifecycle state.
4734            cx.dispatch_event(
4735                Event::MouseDown(MouseButtonEvent {
4736                    position: Default::default(),
4737                    button: MouseButton::Left,
4738                    modifiers: Default::default(),
4739                    click_count: 1,
4740                }),
4741                false,
4742            );
4743            assert_eq!(mouse_down_count.load(SeqCst), 1);
4744        });
4745    }
4746
4747    #[crate::test(self)]
4748    fn test_entity_release_hooks(cx: &mut AppContext) {
4749        struct Model {
4750            released: Rc<Cell<bool>>,
4751        }
4752
4753        struct View {
4754            released: Rc<Cell<bool>>,
4755        }
4756
4757        impl Entity for Model {
4758            type Event = ();
4759
4760            fn release(&mut self, _: &mut AppContext) {
4761                self.released.set(true);
4762            }
4763        }
4764
4765        impl Entity for View {
4766            type Event = ();
4767
4768            fn release(&mut self, _: &mut AppContext) {
4769                self.released.set(true);
4770            }
4771        }
4772
4773        impl super::View for View {
4774            fn ui_name() -> &'static str {
4775                "View"
4776            }
4777
4778            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
4779                Empty::new().into_any()
4780            }
4781        }
4782
4783        let model_released = Rc::new(Cell::new(false));
4784        let model_release_observed = Rc::new(Cell::new(false));
4785        let view_released = Rc::new(Cell::new(false));
4786        let view_release_observed = Rc::new(Cell::new(false));
4787
4788        let model = cx.add_model(|_| Model {
4789            released: model_released.clone(),
4790        });
4791        let (window_id, view) = cx.add_window(Default::default(), |_| View {
4792            released: view_released.clone(),
4793        });
4794        assert!(!model_released.get());
4795        assert!(!view_released.get());
4796
4797        cx.observe_release(&model, {
4798            let model_release_observed = model_release_observed.clone();
4799            move |_, _| model_release_observed.set(true)
4800        })
4801        .detach();
4802        cx.observe_release(&view, {
4803            let view_release_observed = view_release_observed.clone();
4804            move |_, _| view_release_observed.set(true)
4805        })
4806        .detach();
4807
4808        cx.update(move |_| {
4809            drop(model);
4810        });
4811        assert!(model_released.get());
4812        assert!(model_release_observed.get());
4813
4814        drop(view);
4815        cx.update_window(window_id, |cx| cx.remove_window());
4816        assert!(view_released.get());
4817        assert!(view_release_observed.get());
4818    }
4819
4820    #[crate::test(self)]
4821    fn test_view_events(cx: &mut TestAppContext) {
4822        struct Model;
4823
4824        impl Entity for Model {
4825            type Event = String;
4826        }
4827
4828        let (window_id, handle_1) = cx.add_window(|_| TestView::default());
4829        let handle_2 = cx.add_view(window_id, |_| TestView::default());
4830        let handle_3 = cx.add_model(|_| Model);
4831
4832        handle_1.update(cx, |_, cx| {
4833            cx.subscribe(&handle_2, move |me, emitter, event, cx| {
4834                me.events.push(event.clone());
4835
4836                cx.subscribe(&emitter, |me, _, event, _| {
4837                    me.events.push(format!("{event} from inner"));
4838                })
4839                .detach();
4840            })
4841            .detach();
4842
4843            cx.subscribe(&handle_3, |me, _, event, _| {
4844                me.events.push(event.clone());
4845            })
4846            .detach();
4847        });
4848
4849        handle_2.update(cx, |_, c| c.emit("7".into()));
4850        handle_1.read_with(cx, |view, _| assert_eq!(view.events, ["7"]));
4851
4852        handle_2.update(cx, |_, c| c.emit("5".into()));
4853        handle_1.read_with(cx, |view, _| {
4854            assert_eq!(view.events, ["7", "5", "5 from inner"])
4855        });
4856
4857        handle_3.update(cx, |_, c| c.emit("9".into()));
4858        handle_1.read_with(cx, |view, _| {
4859            assert_eq!(view.events, ["7", "5", "5 from inner", "9"])
4860        });
4861    }
4862
4863    #[crate::test(self)]
4864    fn test_global_events(cx: &mut AppContext) {
4865        #[derive(Clone, Debug, Eq, PartialEq)]
4866        struct GlobalEvent(u64);
4867
4868        let events = Rc::new(RefCell::new(Vec::new()));
4869        let first_subscription;
4870        let second_subscription;
4871
4872        {
4873            let events = events.clone();
4874            first_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
4875                events.borrow_mut().push(("First", e.clone()));
4876            });
4877        }
4878
4879        {
4880            let events = events.clone();
4881            second_subscription = cx.subscribe_global(move |e: &GlobalEvent, _| {
4882                events.borrow_mut().push(("Second", e.clone()));
4883            });
4884        }
4885
4886        cx.update(|cx| {
4887            cx.emit_global(GlobalEvent(1));
4888            cx.emit_global(GlobalEvent(2));
4889        });
4890
4891        drop(first_subscription);
4892
4893        cx.update(|cx| {
4894            cx.emit_global(GlobalEvent(3));
4895        });
4896
4897        drop(second_subscription);
4898
4899        cx.update(|cx| {
4900            cx.emit_global(GlobalEvent(4));
4901        });
4902
4903        assert_eq!(
4904            &*events.borrow(),
4905            &[
4906                ("First", GlobalEvent(1)),
4907                ("Second", GlobalEvent(1)),
4908                ("First", GlobalEvent(2)),
4909                ("Second", GlobalEvent(2)),
4910                ("Second", GlobalEvent(3)),
4911            ]
4912        );
4913    }
4914
4915    #[crate::test(self)]
4916    fn test_global_events_emitted_before_subscription_in_same_update_cycle(cx: &mut AppContext) {
4917        let events = Rc::new(RefCell::new(Vec::new()));
4918        cx.update(|cx| {
4919            {
4920                let events = events.clone();
4921                drop(cx.subscribe_global(move |_: &(), _| {
4922                    events.borrow_mut().push("dropped before emit");
4923                }));
4924            }
4925
4926            {
4927                let events = events.clone();
4928                cx.subscribe_global(move |_: &(), _| {
4929                    events.borrow_mut().push("before emit");
4930                })
4931                .detach();
4932            }
4933
4934            cx.emit_global(());
4935
4936            {
4937                let events = events.clone();
4938                cx.subscribe_global(move |_: &(), _| {
4939                    events.borrow_mut().push("after emit");
4940                })
4941                .detach();
4942            }
4943        });
4944
4945        assert_eq!(*events.borrow(), ["before emit"]);
4946    }
4947
4948    #[crate::test(self)]
4949    fn test_global_nested_events(cx: &mut AppContext) {
4950        #[derive(Clone, Debug, Eq, PartialEq)]
4951        struct GlobalEvent(u64);
4952
4953        let events = Rc::new(RefCell::new(Vec::new()));
4954
4955        {
4956            let events = events.clone();
4957            cx.subscribe_global(move |e: &GlobalEvent, cx| {
4958                events.borrow_mut().push(("Outer", e.clone()));
4959
4960                if e.0 == 1 {
4961                    let events = events.clone();
4962                    cx.subscribe_global(move |e: &GlobalEvent, _| {
4963                        events.borrow_mut().push(("Inner", e.clone()));
4964                    })
4965                    .detach();
4966                }
4967            })
4968            .detach();
4969        }
4970
4971        cx.update(|cx| {
4972            cx.emit_global(GlobalEvent(1));
4973            cx.emit_global(GlobalEvent(2));
4974            cx.emit_global(GlobalEvent(3));
4975        });
4976        cx.update(|cx| {
4977            cx.emit_global(GlobalEvent(4));
4978        });
4979
4980        assert_eq!(
4981            &*events.borrow(),
4982            &[
4983                ("Outer", GlobalEvent(1)),
4984                ("Outer", GlobalEvent(2)),
4985                ("Outer", GlobalEvent(3)),
4986                ("Outer", GlobalEvent(4)),
4987                ("Inner", GlobalEvent(4)),
4988            ]
4989        );
4990    }
4991
4992    #[crate::test(self)]
4993    fn test_global(cx: &mut AppContext) {
4994        type Global = usize;
4995
4996        let observation_count = Rc::new(RefCell::new(0));
4997        let subscription = cx.observe_global::<Global, _>({
4998            let observation_count = observation_count.clone();
4999            move |_| {
5000                *observation_count.borrow_mut() += 1;
5001            }
5002        });
5003
5004        assert!(!cx.has_global::<Global>());
5005        assert_eq!(cx.default_global::<Global>(), &0);
5006        assert_eq!(*observation_count.borrow(), 1);
5007        assert!(cx.has_global::<Global>());
5008        assert_eq!(
5009            cx.update_global::<Global, _, _>(|global, _| {
5010                *global = 1;
5011                "Update Result"
5012            }),
5013            "Update Result"
5014        );
5015        assert_eq!(*observation_count.borrow(), 2);
5016        assert_eq!(cx.global::<Global>(), &1);
5017
5018        drop(subscription);
5019        cx.update_global::<Global, _, _>(|global, _| {
5020            *global = 2;
5021        });
5022        assert_eq!(*observation_count.borrow(), 2);
5023
5024        type OtherGlobal = f32;
5025
5026        let observation_count = Rc::new(RefCell::new(0));
5027        cx.observe_global::<OtherGlobal, _>({
5028            let observation_count = observation_count.clone();
5029            move |_| {
5030                *observation_count.borrow_mut() += 1;
5031            }
5032        })
5033        .detach();
5034
5035        assert_eq!(
5036            cx.update_default_global::<OtherGlobal, _, _>(|global, _| {
5037                assert_eq!(global, &0.0);
5038                *global = 2.0;
5039                "Default update result"
5040            }),
5041            "Default update result"
5042        );
5043        assert_eq!(cx.global::<OtherGlobal>(), &2.0);
5044        assert_eq!(*observation_count.borrow(), 1);
5045    }
5046
5047    #[crate::test(self)]
5048    fn test_dropping_subscribers(cx: &mut TestAppContext) {
5049        struct Model;
5050
5051        impl Entity for Model {
5052            type Event = ();
5053        }
5054
5055        let (window_id, _root_view) = cx.add_window(|_| TestView::default());
5056        let observing_view = cx.add_view(window_id, |_| TestView::default());
5057        let emitting_view = cx.add_view(window_id, |_| TestView::default());
5058        let observing_model = cx.add_model(|_| Model);
5059        let observed_model = cx.add_model(|_| Model);
5060
5061        observing_view.update(cx, |_, cx| {
5062            cx.subscribe(&emitting_view, |_, _, _, _| {}).detach();
5063            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
5064        });
5065        observing_model.update(cx, |_, cx| {
5066            cx.subscribe(&observed_model, |_, _, _, _| {}).detach();
5067        });
5068
5069        cx.update(|_| {
5070            drop(observing_view);
5071            drop(observing_model);
5072        });
5073
5074        emitting_view.update(cx, |_, cx| cx.emit(Default::default()));
5075        observed_model.update(cx, |_, cx| cx.emit(()));
5076    }
5077
5078    #[crate::test(self)]
5079    fn test_view_emit_before_subscribe_in_same_update_cycle(cx: &mut AppContext) {
5080        let (_, view) = cx.add_window::<TestView, _>(Default::default(), |cx| {
5081            drop(cx.subscribe(&cx.handle(), {
5082                move |this, _, _, _| this.events.push("dropped before flush".into())
5083            }));
5084            cx.subscribe(&cx.handle(), {
5085                move |this, _, _, _| this.events.push("before emit".into())
5086            })
5087            .detach();
5088            cx.emit("the event".into());
5089            cx.subscribe(&cx.handle(), {
5090                move |this, _, _, _| this.events.push("after emit".into())
5091            })
5092            .detach();
5093            TestView { events: Vec::new() }
5094        });
5095
5096        assert_eq!(view.read(cx).events, ["before emit"]);
5097    }
5098
5099    #[crate::test(self)]
5100    fn test_observe_and_notify_from_view(cx: &mut TestAppContext) {
5101        #[derive(Default)]
5102        struct Model {
5103            state: String,
5104        }
5105
5106        impl Entity for Model {
5107            type Event = ();
5108        }
5109
5110        let (_, view) = cx.add_window(|_| TestView::default());
5111        let model = cx.add_model(|_| Model {
5112            state: "old-state".into(),
5113        });
5114
5115        view.update(cx, |_, c| {
5116            c.observe(&model, |me, observed, cx| {
5117                me.events.push(observed.read(cx).state.clone())
5118            })
5119            .detach();
5120        });
5121
5122        model.update(cx, |model, cx| {
5123            model.state = "new-state".into();
5124            cx.notify();
5125        });
5126        view.read_with(cx, |view, _| assert_eq!(view.events, ["new-state"]));
5127    }
5128
5129    #[crate::test(self)]
5130    fn test_view_notify_before_observe_in_same_update_cycle(cx: &mut AppContext) {
5131        let (_, view) = cx.add_window::<TestView, _>(Default::default(), |cx| {
5132            drop(cx.observe(&cx.handle(), {
5133                move |this, _, _| this.events.push("dropped before flush".into())
5134            }));
5135            cx.observe(&cx.handle(), {
5136                move |this, _, _| this.events.push("before notify".into())
5137            })
5138            .detach();
5139            cx.notify();
5140            cx.observe(&cx.handle(), {
5141                move |this, _, _| this.events.push("after notify".into())
5142            })
5143            .detach();
5144            TestView { events: Vec::new() }
5145        });
5146
5147        assert_eq!(view.read(cx).events, ["before notify"]);
5148    }
5149
5150    #[crate::test(self)]
5151    fn test_notify_and_drop_observe_subscription_in_same_update_cycle(cx: &mut TestAppContext) {
5152        struct Model;
5153        impl Entity for Model {
5154            type Event = ();
5155        }
5156
5157        let model = cx.add_model(|_| Model);
5158        let (_, view) = cx.add_window(|_| TestView::default());
5159
5160        view.update(cx, |_, cx| {
5161            model.update(cx, |_, cx| cx.notify());
5162            drop(cx.observe(&model, move |this, _, _| {
5163                this.events.push("model notified".into());
5164            }));
5165            model.update(cx, |_, cx| cx.notify());
5166        });
5167
5168        for _ in 0..3 {
5169            model.update(cx, |_, cx| cx.notify());
5170        }
5171        view.read_with(cx, |view, _| assert_eq!(view.events, Vec::<&str>::new()));
5172    }
5173
5174    #[crate::test(self)]
5175    fn test_dropping_observers(cx: &mut TestAppContext) {
5176        struct Model;
5177
5178        impl Entity for Model {
5179            type Event = ();
5180        }
5181
5182        let (window_id, _root_view) = cx.add_window(|_| TestView::default());
5183        let observing_view = cx.add_view(window_id, |_| TestView::default());
5184        let observing_model = cx.add_model(|_| Model);
5185        let observed_model = cx.add_model(|_| Model);
5186
5187        observing_view.update(cx, |_, cx| {
5188            cx.observe(&observed_model, |_, _, _| {}).detach();
5189        });
5190        observing_model.update(cx, |_, cx| {
5191            cx.observe(&observed_model, |_, _, _| {}).detach();
5192        });
5193
5194        cx.update(|_| {
5195            drop(observing_view);
5196            drop(observing_model);
5197        });
5198
5199        observed_model.update(cx, |_, cx| cx.notify());
5200    }
5201
5202    #[crate::test(self)]
5203    fn test_dropping_subscriptions_during_callback(cx: &mut TestAppContext) {
5204        struct Model;
5205
5206        impl Entity for Model {
5207            type Event = u64;
5208        }
5209
5210        // Events
5211        let observing_model = cx.add_model(|_| Model);
5212        let observed_model = cx.add_model(|_| Model);
5213
5214        let events = Rc::new(RefCell::new(Vec::new()));
5215
5216        observing_model.update(cx, |_, cx| {
5217            let events = events.clone();
5218            let subscription = Rc::new(RefCell::new(None));
5219            *subscription.borrow_mut() = Some(cx.subscribe(&observed_model, {
5220                let subscription = subscription.clone();
5221                move |_, _, e, _| {
5222                    subscription.borrow_mut().take();
5223                    events.borrow_mut().push(*e);
5224                }
5225            }));
5226        });
5227
5228        observed_model.update(cx, |_, cx| {
5229            cx.emit(1);
5230            cx.emit(2);
5231        });
5232
5233        assert_eq!(*events.borrow(), [1]);
5234
5235        // Global Events
5236        #[derive(Clone, Debug, Eq, PartialEq)]
5237        struct GlobalEvent(u64);
5238
5239        let events = Rc::new(RefCell::new(Vec::new()));
5240
5241        {
5242            let events = events.clone();
5243            let subscription = Rc::new(RefCell::new(None));
5244            *subscription.borrow_mut() = Some(cx.subscribe_global({
5245                let subscription = subscription.clone();
5246                move |e: &GlobalEvent, _| {
5247                    subscription.borrow_mut().take();
5248                    events.borrow_mut().push(e.clone());
5249                }
5250            }));
5251        }
5252
5253        cx.update(|cx| {
5254            cx.emit_global(GlobalEvent(1));
5255            cx.emit_global(GlobalEvent(2));
5256        });
5257
5258        assert_eq!(*events.borrow(), [GlobalEvent(1)]);
5259
5260        // Model Observation
5261        let observing_model = cx.add_model(|_| Model);
5262        let observed_model = cx.add_model(|_| Model);
5263
5264        let observation_count = Rc::new(RefCell::new(0));
5265
5266        observing_model.update(cx, |_, cx| {
5267            let observation_count = observation_count.clone();
5268            let subscription = Rc::new(RefCell::new(None));
5269            *subscription.borrow_mut() = Some(cx.observe(&observed_model, {
5270                let subscription = subscription.clone();
5271                move |_, _, _| {
5272                    subscription.borrow_mut().take();
5273                    *observation_count.borrow_mut() += 1;
5274                }
5275            }));
5276        });
5277
5278        observed_model.update(cx, |_, cx| {
5279            cx.notify();
5280        });
5281
5282        observed_model.update(cx, |_, cx| {
5283            cx.notify();
5284        });
5285
5286        assert_eq!(*observation_count.borrow(), 1);
5287
5288        // View Observation
5289        struct View;
5290
5291        impl Entity for View {
5292            type Event = ();
5293        }
5294
5295        impl super::View for View {
5296            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
5297                Empty::new().into_any()
5298            }
5299
5300            fn ui_name() -> &'static str {
5301                "View"
5302            }
5303        }
5304
5305        let (window_id, _root_view) = cx.add_window(|_| View);
5306        let observing_view = cx.add_view(window_id, |_| View);
5307        let observed_view = cx.add_view(window_id, |_| View);
5308
5309        let observation_count = Rc::new(RefCell::new(0));
5310        observing_view.update(cx, |_, cx| {
5311            let observation_count = observation_count.clone();
5312            let subscription = Rc::new(RefCell::new(None));
5313            *subscription.borrow_mut() = Some(cx.observe(&observed_view, {
5314                let subscription = subscription.clone();
5315                move |_, _, _| {
5316                    subscription.borrow_mut().take();
5317                    *observation_count.borrow_mut() += 1;
5318                }
5319            }));
5320        });
5321
5322        observed_view.update(cx, |_, cx| {
5323            cx.notify();
5324        });
5325
5326        observed_view.update(cx, |_, cx| {
5327            cx.notify();
5328        });
5329
5330        assert_eq!(*observation_count.borrow(), 1);
5331
5332        // Global Observation
5333        let observation_count = Rc::new(RefCell::new(0));
5334        let subscription = Rc::new(RefCell::new(None));
5335        *subscription.borrow_mut() = Some(cx.observe_global::<(), _>({
5336            let observation_count = observation_count.clone();
5337            let subscription = subscription.clone();
5338            move |_| {
5339                subscription.borrow_mut().take();
5340                *observation_count.borrow_mut() += 1;
5341            }
5342        }));
5343
5344        cx.update(|cx| {
5345            cx.default_global::<()>();
5346            cx.set_global(());
5347        });
5348        assert_eq!(*observation_count.borrow(), 1);
5349    }
5350
5351    #[crate::test(self)]
5352    fn test_focus(cx: &mut TestAppContext) {
5353        struct View {
5354            name: String,
5355            events: Arc<Mutex<Vec<String>>>,
5356            child: Option<AnyViewHandle>,
5357        }
5358
5359        impl Entity for View {
5360            type Event = ();
5361        }
5362
5363        impl super::View for View {
5364            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5365                self.child
5366                    .as_ref()
5367                    .map(|child| ChildView::new(child, cx).into_any())
5368                    .unwrap_or(Empty::new().into_any())
5369            }
5370
5371            fn ui_name() -> &'static str {
5372                "View"
5373            }
5374
5375            fn focus_in(&mut self, focused: AnyViewHandle, cx: &mut ViewContext<Self>) {
5376                if cx.handle().id() == focused.id() {
5377                    self.events.lock().push(format!("{} focused", &self.name));
5378                }
5379            }
5380
5381            fn focus_out(&mut self, blurred: AnyViewHandle, cx: &mut ViewContext<Self>) {
5382                if cx.handle().id() == blurred.id() {
5383                    self.events.lock().push(format!("{} blurred", &self.name));
5384                }
5385            }
5386        }
5387
5388        let view_events: Arc<Mutex<Vec<String>>> = Default::default();
5389        let (window_id, view_1) = cx.add_window(|_| View {
5390            events: view_events.clone(),
5391            name: "view 1".to_string(),
5392            child: None,
5393        });
5394        let view_2 = cx
5395            .update_window(window_id, |cx| {
5396                let view_2 = cx.add_view(|_| View {
5397                    events: view_events.clone(),
5398                    name: "view 2".to_string(),
5399                    child: None,
5400                });
5401                view_1.update(cx, |view_1, cx| {
5402                    view_1.child = Some(view_2.clone().into_any());
5403                    cx.notify();
5404                });
5405                view_2
5406            })
5407            .unwrap();
5408
5409        let observed_events: Arc<Mutex<Vec<String>>> = Default::default();
5410        view_1.update(cx, |_, cx| {
5411            cx.observe_focus(&view_2, {
5412                let observed_events = observed_events.clone();
5413                move |this, view, focused, cx| {
5414                    let label = if focused { "focus" } else { "blur" };
5415                    observed_events.lock().push(format!(
5416                        "{} observed {}'s {}",
5417                        this.name,
5418                        view.read(cx).name,
5419                        label
5420                    ))
5421                }
5422            })
5423            .detach();
5424        });
5425        view_2.update(cx, |_, cx| {
5426            cx.observe_focus(&view_1, {
5427                let observed_events = observed_events.clone();
5428                move |this, view, focused, cx| {
5429                    let label = if focused { "focus" } else { "blur" };
5430                    observed_events.lock().push(format!(
5431                        "{} observed {}'s {}",
5432                        this.name,
5433                        view.read(cx).name,
5434                        label
5435                    ))
5436                }
5437            })
5438            .detach();
5439        });
5440        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
5441        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
5442
5443        view_1.update(cx, |_, cx| {
5444            // Ensure only the last focus event is honored.
5445            cx.focus(&view_2);
5446            cx.focus(&view_1);
5447            cx.focus(&view_2);
5448        });
5449
5450        assert_eq!(
5451            mem::take(&mut *view_events.lock()),
5452            ["view 1 blurred", "view 2 focused"],
5453        );
5454        assert_eq!(
5455            mem::take(&mut *observed_events.lock()),
5456            [
5457                "view 2 observed view 1's blur",
5458                "view 1 observed view 2's focus"
5459            ]
5460        );
5461
5462        view_1.update(cx, |_, cx| cx.focus(&view_1));
5463        assert_eq!(
5464            mem::take(&mut *view_events.lock()),
5465            ["view 2 blurred", "view 1 focused"],
5466        );
5467        assert_eq!(
5468            mem::take(&mut *observed_events.lock()),
5469            [
5470                "view 1 observed view 2's blur",
5471                "view 2 observed view 1's focus"
5472            ]
5473        );
5474
5475        view_1.update(cx, |_, cx| cx.focus(&view_2));
5476        assert_eq!(
5477            mem::take(&mut *view_events.lock()),
5478            ["view 1 blurred", "view 2 focused"],
5479        );
5480        assert_eq!(
5481            mem::take(&mut *observed_events.lock()),
5482            [
5483                "view 2 observed view 1's blur",
5484                "view 1 observed view 2's focus"
5485            ]
5486        );
5487
5488        println!("=====================");
5489        view_1.update(cx, |view, _| {
5490            drop(view_2);
5491            view.child = None;
5492        });
5493        assert_eq!(mem::take(&mut *view_events.lock()), ["view 1 focused"]);
5494        assert_eq!(mem::take(&mut *observed_events.lock()), Vec::<&str>::new());
5495    }
5496
5497    #[crate::test(self)]
5498    fn test_deserialize_actions(cx: &mut AppContext) {
5499        #[derive(Clone, Debug, Deserialize, PartialEq, Eq)]
5500        pub struct ComplexAction {
5501            arg: String,
5502            count: usize,
5503        }
5504
5505        actions!(test::something, [SimpleAction]);
5506        impl_actions!(test::something, [ComplexAction]);
5507
5508        cx.add_global_action(move |_: &SimpleAction, _: &mut AppContext| {});
5509        cx.add_global_action(move |_: &ComplexAction, _: &mut AppContext| {});
5510
5511        let action1 = cx
5512            .deserialize_action(
5513                "test::something::ComplexAction",
5514                Some(r#"{"arg": "a", "count": 5}"#),
5515            )
5516            .unwrap();
5517        let action2 = cx
5518            .deserialize_action("test::something::SimpleAction", None)
5519            .unwrap();
5520        assert_eq!(
5521            action1.as_any().downcast_ref::<ComplexAction>().unwrap(),
5522            &ComplexAction {
5523                arg: "a".to_string(),
5524                count: 5,
5525            }
5526        );
5527        assert_eq!(
5528            action2.as_any().downcast_ref::<SimpleAction>().unwrap(),
5529            &SimpleAction
5530        );
5531    }
5532
5533    #[crate::test(self)]
5534    fn test_dispatch_action(cx: &mut AppContext) {
5535        struct ViewA {
5536            id: usize,
5537            child: Option<AnyViewHandle>,
5538        }
5539
5540        impl Entity for ViewA {
5541            type Event = ();
5542        }
5543
5544        impl View for ViewA {
5545            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5546                self.child
5547                    .as_ref()
5548                    .map(|child| ChildView::new(child, cx).into_any())
5549                    .unwrap_or(Empty::new().into_any())
5550            }
5551
5552            fn ui_name() -> &'static str {
5553                "View"
5554            }
5555        }
5556
5557        struct ViewB {
5558            id: usize,
5559            child: Option<AnyViewHandle>,
5560        }
5561
5562        impl Entity for ViewB {
5563            type Event = ();
5564        }
5565
5566        impl View for ViewB {
5567            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5568                self.child
5569                    .as_ref()
5570                    .map(|child| ChildView::new(child, cx).into_any())
5571                    .unwrap_or(Empty::new().into_any())
5572            }
5573
5574            fn ui_name() -> &'static str {
5575                "View"
5576            }
5577        }
5578
5579        #[derive(Clone, Default, Deserialize, PartialEq)]
5580        pub struct Action(pub String);
5581
5582        impl_actions!(test, [Action]);
5583
5584        let actions = Rc::new(RefCell::new(Vec::new()));
5585
5586        cx.add_global_action({
5587            let actions = actions.clone();
5588            move |_: &Action, _: &mut AppContext| {
5589                actions.borrow_mut().push("global".to_string());
5590            }
5591        });
5592
5593        cx.add_action({
5594            let actions = actions.clone();
5595            move |view: &mut ViewA, action: &Action, cx| {
5596                assert_eq!(action.0, "bar");
5597                cx.propagate_action();
5598                actions.borrow_mut().push(format!("{} a", view.id));
5599            }
5600        });
5601
5602        cx.add_action({
5603            let actions = actions.clone();
5604            move |view: &mut ViewA, _: &Action, cx| {
5605                if view.id != 1 {
5606                    cx.add_view(|cx| {
5607                        cx.propagate_action(); // Still works on a nested ViewContext
5608                        ViewB { id: 5, child: None }
5609                    });
5610                }
5611                actions.borrow_mut().push(format!("{} b", view.id));
5612            }
5613        });
5614
5615        cx.add_action({
5616            let actions = actions.clone();
5617            move |view: &mut ViewB, _: &Action, cx| {
5618                cx.propagate_action();
5619                actions.borrow_mut().push(format!("{} c", view.id));
5620            }
5621        });
5622
5623        cx.add_action({
5624            let actions = actions.clone();
5625            move |view: &mut ViewB, _: &Action, cx| {
5626                cx.propagate_action();
5627                actions.borrow_mut().push(format!("{} d", view.id));
5628            }
5629        });
5630
5631        cx.capture_action({
5632            let actions = actions.clone();
5633            move |view: &mut ViewA, _: &Action, cx| {
5634                cx.propagate_action();
5635                actions.borrow_mut().push(format!("{} capture", view.id));
5636            }
5637        });
5638
5639        let observed_actions = Rc::new(RefCell::new(Vec::new()));
5640        cx.observe_actions({
5641            let observed_actions = observed_actions.clone();
5642            move |action_id, _| observed_actions.borrow_mut().push(action_id)
5643        })
5644        .detach();
5645
5646        let (window_id, view_1) =
5647            cx.add_window(Default::default(), |_| ViewA { id: 1, child: None });
5648        let view_2 = cx
5649            .update_window(window_id, |cx| {
5650                let child = cx.add_view(|_| ViewB { id: 2, child: None });
5651                view_1.update(cx, |view, cx| {
5652                    view.child = Some(child.clone().into_any());
5653                    cx.notify();
5654                });
5655                child
5656            })
5657            .unwrap();
5658        let view_3 = cx
5659            .update_window(window_id, |cx| {
5660                let child = cx.add_view(|_| ViewA { id: 3, child: None });
5661                view_2.update(cx, |view, cx| {
5662                    view.child = Some(child.clone().into_any());
5663                    cx.notify();
5664                });
5665                child
5666            })
5667            .unwrap();
5668        let view_4 = cx
5669            .update_window(window_id, |cx| {
5670                let child = cx.add_view(|_| ViewB { id: 4, child: None });
5671                view_3.update(cx, |view, cx| {
5672                    view.child = Some(child.clone().into_any());
5673                    cx.notify();
5674                });
5675                child
5676            })
5677            .unwrap();
5678
5679        cx.update_window(window_id, |cx| {
5680            cx.dispatch_action(Some(view_4.id()), &Action("bar".to_string()))
5681        });
5682
5683        assert_eq!(
5684            *actions.borrow(),
5685            vec![
5686                "1 capture",
5687                "3 capture",
5688                "4 d",
5689                "4 c",
5690                "3 b",
5691                "3 a",
5692                "2 d",
5693                "2 c",
5694                "1 b"
5695            ]
5696        );
5697        assert_eq!(*observed_actions.borrow(), [Action::default().id()]);
5698
5699        // Remove view_1, which doesn't propagate the action
5700
5701        let (window_id, view_2) =
5702            cx.add_window(Default::default(), |_| ViewB { id: 2, child: None });
5703        let view_3 = cx
5704            .update_window(window_id, |cx| {
5705                let child = cx.add_view(|_| ViewA { id: 3, child: None });
5706                view_2.update(cx, |view, cx| {
5707                    view.child = Some(child.clone().into_any());
5708                    cx.notify();
5709                });
5710                child
5711            })
5712            .unwrap();
5713        let view_4 = cx
5714            .update_window(window_id, |cx| {
5715                let child = cx.add_view(|_| ViewB { id: 4, child: None });
5716                view_3.update(cx, |view, cx| {
5717                    view.child = Some(child.clone().into_any());
5718                    cx.notify();
5719                });
5720                child
5721            })
5722            .unwrap();
5723
5724        actions.borrow_mut().clear();
5725        cx.update_window(window_id, |cx| {
5726            cx.dispatch_action(Some(view_4.id()), &Action("bar".to_string()))
5727        });
5728
5729        assert_eq!(
5730            *actions.borrow(),
5731            vec![
5732                "3 capture",
5733                "4 d",
5734                "4 c",
5735                "3 b",
5736                "3 a",
5737                "2 d",
5738                "2 c",
5739                "global"
5740            ]
5741        );
5742        assert_eq!(
5743            *observed_actions.borrow(),
5744            [Action::default().id(), Action::default().id()]
5745        );
5746    }
5747
5748    #[crate::test(self)]
5749    fn test_dispatch_keystroke(cx: &mut AppContext) {
5750        #[derive(Clone, Deserialize, PartialEq)]
5751        pub struct Action(String);
5752
5753        impl_actions!(test, [Action]);
5754
5755        struct View {
5756            id: usize,
5757            keymap_context: KeymapContext,
5758            child: Option<AnyViewHandle>,
5759        }
5760
5761        impl Entity for View {
5762            type Event = ();
5763        }
5764
5765        impl super::View for View {
5766            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5767                self.child
5768                    .as_ref()
5769                    .map(|child| ChildView::new(child, cx).into_any())
5770                    .unwrap_or(Empty::new().into_any())
5771            }
5772
5773            fn ui_name() -> &'static str {
5774                "View"
5775            }
5776
5777            fn update_keymap_context(&self, keymap: &mut KeymapContext, _: &AppContext) {
5778                *keymap = self.keymap_context.clone();
5779            }
5780        }
5781
5782        impl View {
5783            fn new(id: usize) -> Self {
5784                View {
5785                    id,
5786                    keymap_context: KeymapContext::default(),
5787                    child: None,
5788                }
5789            }
5790        }
5791
5792        let mut view_1 = View::new(1);
5793        let mut view_2 = View::new(2);
5794        let mut view_3 = View::new(3);
5795        view_1.keymap_context.add_identifier("a");
5796        view_2.keymap_context.add_identifier("a");
5797        view_2.keymap_context.add_identifier("b");
5798        view_3.keymap_context.add_identifier("a");
5799        view_3.keymap_context.add_identifier("b");
5800        view_3.keymap_context.add_identifier("c");
5801
5802        let (window_id, _view_1) = cx.add_window(Default::default(), |cx| {
5803            let view_2 = cx.add_view(|cx| {
5804                let view_3 = cx.add_view(|cx| {
5805                    cx.focus_self();
5806                    view_3
5807                });
5808                view_2.child = Some(view_3.into_any());
5809                view_2
5810            });
5811            view_1.child = Some(view_2.into_any());
5812            view_1
5813        });
5814
5815        // This binding only dispatches an action on view 2 because that view will have
5816        // "a" and "b" in its context, but not "c".
5817        cx.add_bindings(vec![Binding::new(
5818            "a",
5819            Action("a".to_string()),
5820            Some("a && b && !c"),
5821        )]);
5822
5823        cx.add_bindings(vec![Binding::new("b", Action("b".to_string()), None)]);
5824
5825        // This binding only dispatches an action on views 2 and 3, because they have
5826        // a parent view with a in its context
5827        cx.add_bindings(vec![Binding::new(
5828            "c",
5829            Action("c".to_string()),
5830            Some("b > c"),
5831        )]);
5832
5833        // This binding only dispatches an action on view 2, because they have
5834        // a parent view with a in its context
5835        cx.add_bindings(vec![Binding::new(
5836            "d",
5837            Action("d".to_string()),
5838            Some("a && !b > b"),
5839        )]);
5840
5841        let actions = Rc::new(RefCell::new(Vec::new()));
5842        cx.add_action({
5843            let actions = actions.clone();
5844            move |view: &mut View, action: &Action, cx| {
5845                actions
5846                    .borrow_mut()
5847                    .push(format!("{} {}", view.id, action.0));
5848
5849                if action.0 == "b" {
5850                    cx.propagate_action();
5851                }
5852            }
5853        });
5854
5855        cx.add_global_action({
5856            let actions = actions.clone();
5857            move |action: &Action, _| {
5858                actions.borrow_mut().push(format!("global {}", action.0));
5859            }
5860        });
5861
5862        cx.update_window(window_id, |cx| {
5863            cx.dispatch_keystroke(&Keystroke::parse("a").unwrap())
5864        });
5865        assert_eq!(&*actions.borrow(), &["2 a"]);
5866        actions.borrow_mut().clear();
5867
5868        cx.update_window(window_id, |cx| {
5869            cx.dispatch_keystroke(&Keystroke::parse("b").unwrap());
5870        });
5871
5872        assert_eq!(&*actions.borrow(), &["3 b", "2 b", "1 b", "global b"]);
5873        actions.borrow_mut().clear();
5874
5875        cx.update_window(window_id, |cx| {
5876            cx.dispatch_keystroke(&Keystroke::parse("c").unwrap());
5877        });
5878        assert_eq!(&*actions.borrow(), &["3 c"]);
5879        actions.borrow_mut().clear();
5880
5881        cx.update_window(window_id, |cx| {
5882            cx.dispatch_keystroke(&Keystroke::parse("d").unwrap());
5883        });
5884        assert_eq!(&*actions.borrow(), &["2 d"]);
5885        actions.borrow_mut().clear();
5886    }
5887
5888    #[crate::test(self)]
5889    fn test_keystrokes_for_action(cx: &mut TestAppContext) {
5890        actions!(test, [Action1, Action2, GlobalAction]);
5891
5892        struct View1 {
5893            child: ViewHandle<View2>,
5894        }
5895        struct View2 {}
5896
5897        impl Entity for View1 {
5898            type Event = ();
5899        }
5900        impl Entity for View2 {
5901            type Event = ();
5902        }
5903
5904        impl super::View for View1 {
5905            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
5906                ChildView::new(&self.child, cx).into_any()
5907            }
5908            fn ui_name() -> &'static str {
5909                "View1"
5910            }
5911        }
5912        impl super::View for View2 {
5913            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
5914                Empty::new().into_any()
5915            }
5916            fn ui_name() -> &'static str {
5917                "View2"
5918            }
5919        }
5920
5921        let (window_id, view_1) = cx.add_window(|cx| {
5922            let view_2 = cx.add_view(|cx| {
5923                cx.focus_self();
5924                View2 {}
5925            });
5926            View1 { child: view_2 }
5927        });
5928        let view_2 = view_1.read_with(cx, |view, _| view.child.clone());
5929
5930        cx.update(|cx| {
5931            cx.add_action(|_: &mut View1, _: &Action1, _cx| {});
5932            cx.add_action(|_: &mut View2, _: &Action2, _cx| {});
5933            cx.add_global_action(|_: &GlobalAction, _| {});
5934            cx.add_bindings(vec![
5935                Binding::new("a", Action1, Some("View1")),
5936                Binding::new("b", Action2, Some("View1 > View2")),
5937                Binding::new("c", GlobalAction, Some("View3")), // View 3 does not exist
5938            ]);
5939        });
5940
5941        let view_1_id = view_1.id();
5942        view_1.update(cx, |_, cx| {
5943            view_2.update(cx, |_, cx| {
5944                // Sanity check
5945                let mut new_parents = Default::default();
5946                let mut notify_views_if_parents_change = Default::default();
5947                let mut layout_cx = LayoutContext::new(
5948                    cx,
5949                    &mut new_parents,
5950                    &mut notify_views_if_parents_change,
5951                    false,
5952                );
5953                assert_eq!(
5954                    layout_cx
5955                        .keystrokes_for_action(view_1_id, &Action1)
5956                        .unwrap()
5957                        .as_slice(),
5958                    &[Keystroke::parse("a").unwrap()]
5959                );
5960                assert_eq!(
5961                    layout_cx
5962                        .keystrokes_for_action(view_2.id(), &Action2)
5963                        .unwrap()
5964                        .as_slice(),
5965                    &[Keystroke::parse("b").unwrap()]
5966                );
5967
5968                // The 'a' keystroke propagates up the view tree from view_2
5969                // to view_1. The action, Action1, is handled by view_1.
5970                assert_eq!(
5971                    layout_cx
5972                        .keystrokes_for_action(view_2.id(), &Action1)
5973                        .unwrap()
5974                        .as_slice(),
5975                    &[Keystroke::parse("a").unwrap()]
5976                );
5977
5978                // Actions that are handled below the current view don't have bindings
5979                assert_eq!(layout_cx.keystrokes_for_action(view_1_id, &Action2), None);
5980
5981                // Actions that are handled in other branches of the tree should not have a binding
5982                assert_eq!(
5983                    layout_cx.keystrokes_for_action(view_2.id(), &GlobalAction),
5984                    None
5985                );
5986            });
5987        });
5988
5989        // Check that global actions do not have a binding, even if a binding does exist in another view
5990        assert_eq!(
5991            &available_actions(window_id, view_1.id(), cx),
5992            &[
5993                ("test::Action1", vec![Keystroke::parse("a").unwrap()]),
5994                ("test::GlobalAction", vec![])
5995            ],
5996        );
5997
5998        // Check that view 1 actions and bindings are available even when called from view 2
5999        assert_eq!(
6000            &available_actions(window_id, view_2.id(), cx),
6001            &[
6002                ("test::Action1", vec![Keystroke::parse("a").unwrap()]),
6003                ("test::Action2", vec![Keystroke::parse("b").unwrap()]),
6004                ("test::GlobalAction", vec![]),
6005            ],
6006        );
6007
6008        // Produces a list of actions and key bindings
6009        fn available_actions(
6010            window_id: usize,
6011            view_id: usize,
6012            cx: &TestAppContext,
6013        ) -> Vec<(&'static str, Vec<Keystroke>)> {
6014            cx.available_actions(window_id, view_id)
6015                .into_iter()
6016                .map(|(action_name, _, bindings)| {
6017                    (
6018                        action_name,
6019                        bindings
6020                            .iter()
6021                            .map(|binding| binding.keystrokes()[0].clone())
6022                            .collect::<Vec<_>>(),
6023                    )
6024                })
6025                .sorted_by(|(name1, _), (name2, _)| name1.cmp(name2))
6026                .collect()
6027        }
6028    }
6029
6030    #[crate::test(self)]
6031    async fn test_model_condition(cx: &mut TestAppContext) {
6032        struct Counter(usize);
6033
6034        impl super::Entity for Counter {
6035            type Event = ();
6036        }
6037
6038        impl Counter {
6039            fn inc(&mut self, cx: &mut ModelContext<Self>) {
6040                self.0 += 1;
6041                cx.notify();
6042            }
6043        }
6044
6045        let model = cx.add_model(|_| Counter(0));
6046
6047        let condition1 = model.condition(cx, |model, _| model.0 == 2);
6048        let condition2 = model.condition(cx, |model, _| model.0 == 3);
6049        smol::pin!(condition1, condition2);
6050
6051        model.update(cx, |model, cx| model.inc(cx));
6052        assert_eq!(poll_once(&mut condition1).await, None);
6053        assert_eq!(poll_once(&mut condition2).await, None);
6054
6055        model.update(cx, |model, cx| model.inc(cx));
6056        assert_eq!(poll_once(&mut condition1).await, Some(()));
6057        assert_eq!(poll_once(&mut condition2).await, None);
6058
6059        model.update(cx, |model, cx| model.inc(cx));
6060        assert_eq!(poll_once(&mut condition2).await, Some(()));
6061
6062        model.update(cx, |_, cx| cx.notify());
6063    }
6064
6065    #[crate::test(self)]
6066    #[should_panic]
6067    async fn test_model_condition_timeout(cx: &mut TestAppContext) {
6068        struct Model;
6069
6070        impl super::Entity for Model {
6071            type Event = ();
6072        }
6073
6074        let model = cx.add_model(|_| Model);
6075        model.condition(cx, |_, _| false).await;
6076    }
6077
6078    #[crate::test(self)]
6079    #[should_panic(expected = "model dropped with pending condition")]
6080    async fn test_model_condition_panic_on_drop(cx: &mut TestAppContext) {
6081        struct Model;
6082
6083        impl super::Entity for Model {
6084            type Event = ();
6085        }
6086
6087        let model = cx.add_model(|_| Model);
6088        let condition = model.condition(cx, |_, _| false);
6089        cx.update(|_| drop(model));
6090        condition.await;
6091    }
6092
6093    #[crate::test(self)]
6094    async fn test_view_condition(cx: &mut TestAppContext) {
6095        struct Counter(usize);
6096
6097        impl super::Entity for Counter {
6098            type Event = ();
6099        }
6100
6101        impl super::View for Counter {
6102            fn ui_name() -> &'static str {
6103                "test view"
6104            }
6105
6106            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6107                Empty::new().into_any()
6108            }
6109        }
6110
6111        impl Counter {
6112            fn inc(&mut self, cx: &mut ViewContext<Self>) {
6113                self.0 += 1;
6114                cx.notify();
6115            }
6116        }
6117
6118        let (_, view) = cx.add_window(|_| Counter(0));
6119
6120        let condition1 = view.condition(cx, |view, _| view.0 == 2);
6121        let condition2 = view.condition(cx, |view, _| view.0 == 3);
6122        smol::pin!(condition1, condition2);
6123
6124        view.update(cx, |view, cx| view.inc(cx));
6125        assert_eq!(poll_once(&mut condition1).await, None);
6126        assert_eq!(poll_once(&mut condition2).await, None);
6127
6128        view.update(cx, |view, cx| view.inc(cx));
6129        assert_eq!(poll_once(&mut condition1).await, Some(()));
6130        assert_eq!(poll_once(&mut condition2).await, None);
6131
6132        view.update(cx, |view, cx| view.inc(cx));
6133        assert_eq!(poll_once(&mut condition2).await, Some(()));
6134        view.update(cx, |_, cx| cx.notify());
6135    }
6136
6137    #[crate::test(self)]
6138    #[should_panic]
6139    async fn test_view_condition_timeout(cx: &mut TestAppContext) {
6140        let (_, view) = cx.add_window(|_| TestView::default());
6141        view.condition(cx, |_, _| false).await;
6142    }
6143
6144    #[crate::test(self)]
6145    #[should_panic(expected = "view dropped with pending condition")]
6146    async fn test_view_condition_panic_on_drop(cx: &mut TestAppContext) {
6147        let (window_id, _root_view) = cx.add_window(|_| TestView::default());
6148        let view = cx.add_view(window_id, |_| TestView::default());
6149
6150        let condition = view.condition(cx, |_, _| false);
6151        cx.update(|_| drop(view));
6152        condition.await;
6153    }
6154
6155    #[crate::test(self)]
6156    fn test_refresh_windows(cx: &mut AppContext) {
6157        struct View(usize);
6158
6159        impl super::Entity for View {
6160            type Event = ();
6161        }
6162
6163        impl super::View for View {
6164            fn ui_name() -> &'static str {
6165                "test view"
6166            }
6167
6168            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6169                Empty::new().into_any_named(format!("render count: {}", post_inc(&mut self.0)))
6170            }
6171        }
6172
6173        let (window_id, root_view) = cx.add_window(Default::default(), |_| View(0));
6174        cx.update_window(window_id, |cx| {
6175            assert_eq!(
6176                cx.window.rendered_views[&root_view.id()].name(),
6177                Some("render count: 0")
6178            );
6179        });
6180
6181        let view = cx
6182            .update_window(window_id, |cx| {
6183                cx.refresh_windows();
6184                cx.add_view(|_| View(0))
6185            })
6186            .unwrap();
6187
6188        cx.update_window(window_id, |cx| {
6189            assert_eq!(
6190                cx.window.rendered_views[&root_view.id()].name(),
6191                Some("render count: 1")
6192            );
6193            assert_eq!(
6194                cx.window.rendered_views[&view.id()].name(),
6195                Some("render count: 0")
6196            );
6197        });
6198
6199        cx.update(|cx| cx.refresh_windows());
6200
6201        cx.update_window(window_id, |cx| {
6202            assert_eq!(
6203                cx.window.rendered_views[&root_view.id()].name(),
6204                Some("render count: 2")
6205            );
6206            assert_eq!(
6207                cx.window.rendered_views[&view.id()].name(),
6208                Some("render count: 1")
6209            );
6210        });
6211
6212        cx.update(|cx| {
6213            cx.refresh_windows();
6214            drop(view);
6215        });
6216
6217        cx.update_window(window_id, |cx| {
6218            assert_eq!(
6219                cx.window.rendered_views[&root_view.id()].name(),
6220                Some("render count: 3")
6221            );
6222            assert_eq!(cx.window.rendered_views.len(), 1);
6223        });
6224    }
6225
6226    #[crate::test(self)]
6227    async fn test_labeled_tasks(cx: &mut TestAppContext) {
6228        assert_eq!(None, cx.update(|cx| cx.active_labeled_tasks().next()));
6229        let (mut sender, mut reciever) = postage::oneshot::channel::<()>();
6230        let task = cx
6231            .update(|cx| cx.spawn_labeled("Test Label", |_| async move { reciever.recv().await }));
6232
6233        assert_eq!(
6234            Some("Test Label"),
6235            cx.update(|cx| cx.active_labeled_tasks().next())
6236        );
6237        sender
6238            .send(())
6239            .await
6240            .expect("Could not send message to complete task");
6241        task.await;
6242
6243        assert_eq!(None, cx.update(|cx| cx.active_labeled_tasks().next()));
6244    }
6245
6246    #[crate::test(self)]
6247    async fn test_window_activation(cx: &mut TestAppContext) {
6248        struct View(&'static str);
6249
6250        impl super::Entity for View {
6251            type Event = ();
6252        }
6253
6254        impl super::View for View {
6255            fn ui_name() -> &'static str {
6256                "test view"
6257            }
6258
6259            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6260                Empty::new().into_any()
6261            }
6262        }
6263
6264        let events = Rc::new(RefCell::new(Vec::new()));
6265        let (window_1, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6266            cx.observe_window_activation({
6267                let events = events.clone();
6268                move |this, active, _| events.borrow_mut().push((this.0, active))
6269            })
6270            .detach();
6271            View("window 1")
6272        });
6273        assert_eq!(mem::take(&mut *events.borrow_mut()), [("window 1", true)]);
6274
6275        let (window_2, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6276            cx.observe_window_activation({
6277                let events = events.clone();
6278                move |this, active, _| events.borrow_mut().push((this.0, active))
6279            })
6280            .detach();
6281            View("window 2")
6282        });
6283        assert_eq!(
6284            mem::take(&mut *events.borrow_mut()),
6285            [("window 1", false), ("window 2", true)]
6286        );
6287
6288        let (window_3, _) = cx.add_window(|cx: &mut ViewContext<View>| {
6289            cx.observe_window_activation({
6290                let events = events.clone();
6291                move |this, active, _| events.borrow_mut().push((this.0, active))
6292            })
6293            .detach();
6294            View("window 3")
6295        });
6296        assert_eq!(
6297            mem::take(&mut *events.borrow_mut()),
6298            [("window 2", false), ("window 3", true)]
6299        );
6300
6301        cx.simulate_window_activation(Some(window_2));
6302        assert_eq!(
6303            mem::take(&mut *events.borrow_mut()),
6304            [("window 3", false), ("window 2", true)]
6305        );
6306
6307        cx.simulate_window_activation(Some(window_1));
6308        assert_eq!(
6309            mem::take(&mut *events.borrow_mut()),
6310            [("window 2", false), ("window 1", true)]
6311        );
6312
6313        cx.simulate_window_activation(Some(window_3));
6314        assert_eq!(
6315            mem::take(&mut *events.borrow_mut()),
6316            [("window 1", false), ("window 3", true)]
6317        );
6318
6319        cx.simulate_window_activation(Some(window_3));
6320        assert_eq!(mem::take(&mut *events.borrow_mut()), []);
6321    }
6322
6323    #[crate::test(self)]
6324    fn test_child_view(cx: &mut TestAppContext) {
6325        struct Child {
6326            rendered: Rc<Cell<bool>>,
6327            dropped: Rc<Cell<bool>>,
6328        }
6329
6330        impl super::Entity for Child {
6331            type Event = ();
6332        }
6333
6334        impl super::View for Child {
6335            fn ui_name() -> &'static str {
6336                "child view"
6337            }
6338
6339            fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6340                self.rendered.set(true);
6341                Empty::new().into_any()
6342            }
6343        }
6344
6345        impl Drop for Child {
6346            fn drop(&mut self) {
6347                self.dropped.set(true);
6348            }
6349        }
6350
6351        struct Parent {
6352            child: Option<ViewHandle<Child>>,
6353        }
6354
6355        impl super::Entity for Parent {
6356            type Event = ();
6357        }
6358
6359        impl super::View for Parent {
6360            fn ui_name() -> &'static str {
6361                "parent view"
6362            }
6363
6364            fn render(&mut self, cx: &mut ViewContext<Self>) -> AnyElement<Self> {
6365                if let Some(child) = self.child.as_ref() {
6366                    ChildView::new(child, cx).into_any()
6367                } else {
6368                    Empty::new().into_any()
6369                }
6370            }
6371        }
6372
6373        let child_rendered = Rc::new(Cell::new(false));
6374        let child_dropped = Rc::new(Cell::new(false));
6375        let (_, root_view) = cx.add_window(|cx| Parent {
6376            child: Some(cx.add_view(|_| Child {
6377                rendered: child_rendered.clone(),
6378                dropped: child_dropped.clone(),
6379            })),
6380        });
6381        assert!(child_rendered.take());
6382        assert!(!child_dropped.take());
6383
6384        root_view.update(cx, |view, cx| {
6385            view.child.take();
6386            cx.notify();
6387        });
6388        assert!(!child_rendered.take());
6389        assert!(child_dropped.take());
6390    }
6391
6392    #[derive(Default)]
6393    struct TestView {
6394        events: Vec<String>,
6395    }
6396
6397    impl Entity for TestView {
6398        type Event = String;
6399    }
6400
6401    impl View for TestView {
6402        fn ui_name() -> &'static str {
6403            "TestView"
6404        }
6405
6406        fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
6407            Empty::new().into_any()
6408        }
6409    }
6410}