app.rs

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