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