app.rs

  1mod async_context;
  2mod entity_map;
  3mod model_context;
  4
  5pub use async_context::*;
  6pub use entity_map::*;
  7pub use model_context::*;
  8use refineable::Refineable;
  9use smallvec::SmallVec;
 10
 11use crate::{
 12    current_platform, image_cache::ImageCache, Action, AnyBox, AnyView, AppMetadata, AssetSource,
 13    ClipboardItem, Context, DispatchPhase, DisplayId, Executor, FocusEvent, FocusHandle, FocusId,
 14    KeyBinding, Keymap, LayoutId, MainThread, MainThreadOnly, Pixels, Platform, Point,
 15    SharedString, SubscriberSet, Subscription, SvgRenderer, Task, TextStyle, TextStyleRefinement,
 16    TextSystem, View, Window, WindowContext, WindowHandle, WindowId,
 17};
 18use anyhow::{anyhow, Result};
 19use collections::{HashMap, HashSet, VecDeque};
 20use futures::{future::BoxFuture, Future};
 21use parking_lot::{Mutex, RwLock};
 22use slotmap::SlotMap;
 23use std::{
 24    any::{type_name, Any, TypeId},
 25    borrow::Borrow,
 26    mem,
 27    sync::{atomic::Ordering::SeqCst, Arc, Weak},
 28    time::Duration,
 29};
 30use util::http::{self, HttpClient};
 31
 32pub struct App(Arc<Mutex<AppContext>>);
 33
 34impl App {
 35    pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
 36        let http_client = http::client();
 37        Self::new(current_platform(), asset_source, http_client)
 38    }
 39
 40    #[cfg(any(test, feature = "test"))]
 41    pub fn test() -> Self {
 42        let platform = Arc::new(super::TestPlatform::new());
 43        let asset_source = Arc::new(());
 44        let http_client = util::http::FakeHttpClient::with_404_response();
 45        Self::new(platform, asset_source, http_client)
 46    }
 47
 48    fn new(
 49        platform: Arc<dyn Platform>,
 50        asset_source: Arc<dyn AssetSource>,
 51        http_client: Arc<dyn HttpClient>,
 52    ) -> Self {
 53        let executor = platform.executor();
 54        assert!(
 55            executor.is_main_thread(),
 56            "must construct App on main thread"
 57        );
 58
 59        let text_system = Arc::new(TextSystem::new(platform.text_system()));
 60        let mut entities = EntityMap::new();
 61        let unit_entity = entities.insert(entities.reserve(), ());
 62        let app_metadata = AppMetadata {
 63            os_name: platform.os_name(),
 64            os_version: platform.os_version().ok(),
 65            app_version: platform.app_version().ok(),
 66        };
 67        Self(Arc::new_cyclic(|this| {
 68            Mutex::new(AppContext {
 69                this: this.clone(),
 70                text_system,
 71                platform: MainThreadOnly::new(platform, executor.clone()),
 72                app_metadata,
 73                flushing_effects: false,
 74                pending_updates: 0,
 75                next_frame_callbacks: Default::default(),
 76                executor,
 77                svg_renderer: SvgRenderer::new(asset_source),
 78                image_cache: ImageCache::new(http_client),
 79                text_style_stack: Vec::new(),
 80                globals_by_type: HashMap::default(),
 81                unit_entity,
 82                entities,
 83                windows: SlotMap::with_key(),
 84                keymap: Arc::new(RwLock::new(Keymap::default())),
 85                global_action_listeners: HashMap::default(),
 86                action_builders: HashMap::default(),
 87                pending_effects: VecDeque::new(),
 88                pending_notifications: HashSet::default(),
 89                pending_global_notifications: HashSet::default(),
 90                observers: SubscriberSet::new(),
 91                event_listeners: SubscriberSet::new(),
 92                release_listeners: SubscriberSet::new(),
 93                global_observers: SubscriberSet::new(),
 94                quit_observers: SubscriberSet::new(),
 95                layout_id_buffer: Default::default(),
 96                propagate_event: true,
 97                active_drag: None,
 98            })
 99        }))
100    }
101
102    pub fn run<F>(self, on_finish_launching: F)
103    where
104        F: 'static + FnOnce(&mut MainThread<AppContext>),
105    {
106        let this = self.0.clone();
107        let platform = self.0.lock().platform.clone();
108        platform.borrow_on_main_thread().run(Box::new(move || {
109            let cx = &mut *this.lock();
110            let cx = unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) };
111            on_finish_launching(cx);
112        }));
113    }
114
115    pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
116    where
117        F: 'static + FnMut(Vec<String>, &mut AppContext),
118    {
119        let this = Arc::downgrade(&self.0);
120        self.0
121            .lock()
122            .platform
123            .borrow_on_main_thread()
124            .on_open_urls(Box::new(move |urls| {
125                if let Some(app) = this.upgrade() {
126                    callback(urls, &mut app.lock());
127                }
128            }));
129        self
130    }
131
132    pub fn on_reopen<F>(&self, mut callback: F) -> &Self
133    where
134        F: 'static + FnMut(&mut AppContext),
135    {
136        let this = Arc::downgrade(&self.0);
137        self.0
138            .lock()
139            .platform
140            .borrow_on_main_thread()
141            .on_reopen(Box::new(move || {
142                if let Some(app) = this.upgrade() {
143                    callback(&mut app.lock());
144                }
145            }));
146        self
147    }
148
149    pub fn metadata(&self) -> AppMetadata {
150        self.0.lock().app_metadata.clone()
151    }
152
153    pub fn executor(&self) -> Executor {
154        self.0.lock().executor.clone()
155    }
156
157    pub fn text_system(&self) -> Arc<TextSystem> {
158        self.0.lock().text_system.clone()
159    }
160}
161
162type ActionBuilder = fn(json: Option<serde_json::Value>) -> anyhow::Result<Box<dyn Action>>;
163type FrameCallback = Box<dyn FnOnce(&mut WindowContext) + Send>;
164type Handler = Box<dyn Fn(&mut AppContext) -> bool + Send + Sync + 'static>;
165type Listener = Box<dyn Fn(&dyn Any, &mut AppContext) -> bool + Send + Sync + 'static>;
166type QuitHandler = Box<dyn Fn(&mut AppContext) -> BoxFuture<'static, ()> + Send + Sync + 'static>;
167type ReleaseListener = Box<dyn Fn(&mut dyn Any, &mut AppContext) + Send + Sync + 'static>;
168
169pub struct AppContext {
170    this: Weak<Mutex<AppContext>>,
171    pub(crate) platform: MainThreadOnly<dyn Platform>,
172    app_metadata: AppMetadata,
173    text_system: Arc<TextSystem>,
174    flushing_effects: bool,
175    pending_updates: usize,
176    pub(crate) active_drag: Option<AnyDrag>,
177    pub(crate) next_frame_callbacks: HashMap<DisplayId, Vec<FrameCallback>>,
178    pub(crate) executor: Executor,
179    pub(crate) svg_renderer: SvgRenderer,
180    pub(crate) image_cache: ImageCache,
181    pub(crate) text_style_stack: Vec<TextStyleRefinement>,
182    pub(crate) globals_by_type: HashMap<TypeId, Box<dyn Any + Send + Sync>>,
183    pub(crate) unit_entity: Handle<()>,
184    pub(crate) entities: EntityMap,
185    pub(crate) windows: SlotMap<WindowId, Option<Window>>,
186    pub(crate) keymap: Arc<RwLock<Keymap>>,
187    pub(crate) global_action_listeners:
188        HashMap<TypeId, Vec<Box<dyn Fn(&dyn Action, DispatchPhase, &mut Self) + Send + Sync>>>,
189    action_builders: HashMap<SharedString, ActionBuilder>,
190    pending_effects: VecDeque<Effect>,
191    pub(crate) pending_notifications: HashSet<EntityId>,
192    pub(crate) pending_global_notifications: HashSet<TypeId>,
193    pub(crate) observers: SubscriberSet<EntityId, Handler>,
194    pub(crate) event_listeners: SubscriberSet<EntityId, Listener>,
195    pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
196    pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
197    pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
198    pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
199    pub(crate) propagate_event: bool,
200}
201
202impl AppContext {
203    pub fn quit(&mut self) {
204        let mut futures = Vec::new();
205
206        self.quit_observers.clone().retain(&(), |observer| {
207            futures.push(observer(self));
208            true
209        });
210
211        self.windows.clear();
212        self.flush_effects();
213
214        let futures = futures::future::join_all(futures);
215        if self
216            .executor
217            .block_with_timeout(Duration::from_millis(100), futures)
218            .is_err()
219        {
220            log::error!("timed out waiting on app_will_quit");
221        }
222    }
223
224    pub fn app_metadata(&self) -> AppMetadata {
225        self.app_metadata.clone()
226    }
227
228    pub fn refresh(&mut self) {
229        self.pending_effects.push_back(Effect::Refresh);
230    }
231
232    pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
233        self.pending_updates += 1;
234        let result = update(self);
235        if !self.flushing_effects && self.pending_updates == 1 {
236            self.flushing_effects = true;
237            self.flush_effects();
238            self.flushing_effects = false;
239        }
240        self.pending_updates -= 1;
241        result
242    }
243
244    pub(crate) fn read_window<R>(
245        &mut self,
246        id: WindowId,
247        read: impl FnOnce(&WindowContext) -> R,
248    ) -> Result<R> {
249        let window = self
250            .windows
251            .get(id)
252            .ok_or_else(|| anyhow!("window not found"))?
253            .as_ref()
254            .unwrap();
255        Ok(read(&WindowContext::immutable(self, &window)))
256    }
257
258    pub(crate) fn update_window<R>(
259        &mut self,
260        id: WindowId,
261        update: impl FnOnce(&mut WindowContext) -> R,
262    ) -> Result<R> {
263        self.update(|cx| {
264            let mut window = cx
265                .windows
266                .get_mut(id)
267                .ok_or_else(|| anyhow!("window not found"))?
268                .take()
269                .unwrap();
270
271            let result = update(&mut WindowContext::mutable(cx, &mut window));
272
273            cx.windows
274                .get_mut(id)
275                .ok_or_else(|| anyhow!("window not found"))?
276                .replace(window);
277
278            Ok(result)
279        })
280    }
281
282    pub(crate) fn push_effect(&mut self, effect: Effect) {
283        match &effect {
284            Effect::Notify { emitter } => {
285                if !self.pending_notifications.insert(*emitter) {
286                    return;
287                }
288            }
289            Effect::NotifyGlobalObservers { global_type } => {
290                if !self.pending_global_notifications.insert(*global_type) {
291                    return;
292                }
293            }
294            _ => {}
295        };
296
297        self.pending_effects.push_back(effect);
298    }
299
300    fn flush_effects(&mut self) {
301        loop {
302            self.release_dropped_entities();
303            self.release_dropped_focus_handles();
304            if let Some(effect) = self.pending_effects.pop_front() {
305                match effect {
306                    Effect::Notify { emitter } => {
307                        self.apply_notify_effect(emitter);
308                    }
309                    Effect::Emit { emitter, event } => self.apply_emit_effect(emitter, event),
310                    Effect::FocusChanged { window_id, focused } => {
311                        self.apply_focus_changed_effect(window_id, focused);
312                    }
313                    Effect::Refresh => {
314                        self.apply_refresh_effect();
315                    }
316                    Effect::NotifyGlobalObservers { global_type } => {
317                        self.apply_notify_global_observers_effect(global_type);
318                    }
319                    Effect::Defer { callback } => {
320                        self.apply_defer_effect(callback);
321                    }
322                }
323            } else {
324                break;
325            }
326        }
327
328        let dirty_window_ids = self
329            .windows
330            .iter()
331            .filter_map(|(window_id, window)| {
332                let window = window.as_ref().unwrap();
333                if window.dirty {
334                    Some(window_id)
335                } else {
336                    None
337                }
338            })
339            .collect::<SmallVec<[_; 8]>>();
340
341        for dirty_window_id in dirty_window_ids {
342            self.update_window(dirty_window_id, |cx| cx.draw()).unwrap();
343        }
344    }
345
346    fn release_dropped_entities(&mut self) {
347        loop {
348            let dropped = self.entities.take_dropped();
349            if dropped.is_empty() {
350                break;
351            }
352
353            for (entity_id, mut entity) in dropped {
354                self.observers.remove(&entity_id);
355                self.event_listeners.remove(&entity_id);
356                for release_callback in self.release_listeners.remove(&entity_id) {
357                    release_callback(&mut entity, self);
358                }
359            }
360        }
361    }
362
363    fn release_dropped_focus_handles(&mut self) {
364        let window_ids = self.windows.keys().collect::<SmallVec<[_; 8]>>();
365        for window_id in window_ids {
366            self.update_window(window_id, |cx| {
367                let mut blur_window = false;
368                let focus = cx.window.focus;
369                cx.window.focus_handles.write().retain(|handle_id, count| {
370                    if count.load(SeqCst) == 0 {
371                        if focus == Some(handle_id) {
372                            blur_window = true;
373                        }
374                        false
375                    } else {
376                        true
377                    }
378                });
379
380                if blur_window {
381                    cx.blur();
382                }
383            })
384            .unwrap();
385        }
386    }
387
388    fn apply_notify_effect(&mut self, emitter: EntityId) {
389        self.pending_notifications.remove(&emitter);
390        self.observers
391            .clone()
392            .retain(&emitter, |handler| handler(self));
393    }
394
395    fn apply_emit_effect(&mut self, emitter: EntityId, event: Box<dyn Any>) {
396        self.event_listeners
397            .clone()
398            .retain(&emitter, |handler| handler(&event, self));
399    }
400
401    fn apply_focus_changed_effect(&mut self, window_id: WindowId, focused: Option<FocusId>) {
402        self.update_window(window_id, |cx| {
403            if cx.window.focus == focused {
404                let mut listeners = mem::take(&mut cx.window.focus_listeners);
405                let focused =
406                    focused.map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
407                let blurred = cx
408                    .window
409                    .last_blur
410                    .take()
411                    .unwrap()
412                    .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
413                if focused.is_some() || blurred.is_some() {
414                    let event = FocusEvent { focused, blurred };
415                    for listener in &listeners {
416                        listener(&event, cx);
417                    }
418                }
419
420                listeners.extend(cx.window.focus_listeners.drain(..));
421                cx.window.focus_listeners = listeners;
422            }
423        })
424        .ok();
425    }
426
427    fn apply_refresh_effect(&mut self) {
428        for window in self.windows.values_mut() {
429            if let Some(window) = window.as_mut() {
430                window.dirty = true;
431            }
432        }
433    }
434
435    fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
436        self.pending_global_notifications.remove(&type_id);
437        self.global_observers
438            .clone()
439            .retain(&type_id, |observer| observer(self));
440    }
441
442    fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + Send + Sync + 'static>) {
443        callback(self);
444    }
445
446    pub fn to_async(&self) -> AsyncAppContext {
447        AsyncAppContext {
448            app: unsafe { mem::transmute(self.this.clone()) },
449            executor: self.executor.clone(),
450        }
451    }
452
453    pub fn executor(&self) -> &Executor {
454        &self.executor
455    }
456
457    pub fn run_on_main<R>(
458        &mut self,
459        f: impl FnOnce(&mut MainThread<AppContext>) -> R + Send + 'static,
460    ) -> Task<R>
461    where
462        R: Send + 'static,
463    {
464        if self.executor.is_main_thread() {
465            Task::ready(f(unsafe {
466                mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(self)
467            }))
468        } else {
469            let this = self.this.upgrade().unwrap();
470            self.executor.run_on_main(move || {
471                let cx = &mut *this.lock();
472                cx.update(|cx| f(unsafe { mem::transmute::<&mut Self, &mut MainThread<Self>>(cx) }))
473            })
474        }
475    }
476
477    pub fn spawn_on_main<F, R>(
478        &self,
479        f: impl FnOnce(MainThread<AsyncAppContext>) -> F + Send + 'static,
480    ) -> Task<R>
481    where
482        F: Future<Output = R> + 'static,
483        R: Send + 'static,
484    {
485        let cx = self.to_async();
486        self.executor.spawn_on_main(move || f(MainThread(cx)))
487    }
488
489    pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static) -> Task<R>
490    where
491        Fut: Future<Output = R> + Send + 'static,
492        R: Send + 'static,
493    {
494        let cx = self.to_async();
495        self.executor.spawn(async move {
496            let future = f(cx);
497            future.await
498        })
499    }
500
501    pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static + Send + Sync) {
502        self.push_effect(Effect::Defer {
503            callback: Box::new(f),
504        });
505    }
506
507    pub fn text_system(&self) -> &Arc<TextSystem> {
508        &self.text_system
509    }
510
511    pub fn text_style(&self) -> TextStyle {
512        let mut style = TextStyle::default();
513        for refinement in &self.text_style_stack {
514            style.refine(refinement);
515        }
516        style
517    }
518
519    pub fn has_global<G: 'static>(&self) -> bool {
520        self.globals_by_type.contains_key(&TypeId::of::<G>())
521    }
522
523    pub fn global<G: 'static>(&self) -> &G {
524        self.globals_by_type
525            .get(&TypeId::of::<G>())
526            .map(|any_state| any_state.downcast_ref::<G>().unwrap())
527            .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
528            .unwrap()
529    }
530
531    pub fn try_global<G: 'static>(&self) -> Option<&G> {
532        self.globals_by_type
533            .get(&TypeId::of::<G>())
534            .map(|any_state| any_state.downcast_ref::<G>().unwrap())
535    }
536
537    pub fn global_mut<G: 'static>(&mut self) -> &mut G {
538        let global_type = TypeId::of::<G>();
539        self.push_effect(Effect::NotifyGlobalObservers { global_type });
540        self.globals_by_type
541            .get_mut(&global_type)
542            .and_then(|any_state| any_state.downcast_mut::<G>())
543            .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
544            .unwrap()
545    }
546
547    pub fn default_global_mut<G: 'static + Default + Sync + Send>(&mut self) -> &mut G {
548        let global_type = TypeId::of::<G>();
549        self.push_effect(Effect::NotifyGlobalObservers { global_type });
550        self.globals_by_type
551            .entry(global_type)
552            .or_insert_with(|| Box::new(G::default()))
553            .downcast_mut::<G>()
554            .unwrap()
555    }
556
557    pub fn set_global<T: Send + Sync + 'static>(&mut self, global: T) {
558        let global_type = TypeId::of::<T>();
559        self.push_effect(Effect::NotifyGlobalObservers { global_type });
560        self.globals_by_type.insert(global_type, Box::new(global));
561    }
562
563    pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
564    where
565        G: 'static + Send + Sync,
566    {
567        let mut global = self.lease_global::<G>();
568        let result = f(global.as_mut(), self);
569        self.restore_global(global);
570        result
571    }
572
573    pub fn observe_global<G: 'static>(
574        &mut self,
575        f: impl Fn(&mut Self) + Send + Sync + 'static,
576    ) -> Subscription {
577        self.global_observers.insert(
578            TypeId::of::<G>(),
579            Box::new(move |cx| {
580                f(cx);
581                true
582            }),
583        )
584    }
585
586    pub(crate) fn lease_global<G: 'static + Send + Sync>(&mut self) -> Box<G> {
587        self.globals_by_type
588            .remove(&TypeId::of::<G>())
589            .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
590            .unwrap()
591            .downcast()
592            .unwrap()
593    }
594
595    pub(crate) fn restore_global<G: 'static + Send + Sync>(&mut self, global: Box<G>) {
596        let global_type = TypeId::of::<G>();
597        self.push_effect(Effect::NotifyGlobalObservers { global_type });
598        self.globals_by_type.insert(global_type, global);
599    }
600
601    pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
602        self.text_style_stack.push(text_style);
603    }
604
605    pub(crate) fn pop_text_style(&mut self) {
606        self.text_style_stack.pop();
607    }
608
609    pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
610        self.keymap.write().add_bindings(bindings);
611        self.pending_effects.push_back(Effect::Refresh);
612    }
613
614    pub fn on_action<A: Action>(
615        &mut self,
616        listener: impl Fn(&A, &mut Self) + Send + Sync + 'static,
617    ) {
618        self.global_action_listeners
619            .entry(TypeId::of::<A>())
620            .or_default()
621            .push(Box::new(move |action, phase, cx| {
622                if phase == DispatchPhase::Bubble {
623                    let action = action.as_any().downcast_ref().unwrap();
624                    listener(action, cx)
625                }
626            }));
627    }
628
629    pub fn register_action_type<A: Action>(&mut self) {
630        self.action_builders.insert(A::qualified_name(), A::build);
631    }
632
633    pub fn build_action(
634        &mut self,
635        name: &str,
636        params: Option<serde_json::Value>,
637    ) -> Result<Box<dyn Action>> {
638        let build = self
639            .action_builders
640            .get(name)
641            .ok_or_else(|| anyhow!("no action type registered for {}", name))?;
642        (build)(params)
643    }
644
645    pub fn stop_propagation(&mut self) {
646        self.propagate_event = false;
647    }
648}
649
650impl Context for AppContext {
651    type EntityContext<'a, 'w, T: Send + Sync + 'static> = ModelContext<'a, T>;
652    type Result<T> = T;
653
654    fn entity<T: Send + Sync + 'static>(
655        &mut self,
656        build_entity: impl FnOnce(&mut Self::EntityContext<'_, '_, T>) -> T,
657    ) -> Handle<T> {
658        self.update(|cx| {
659            let slot = cx.entities.reserve();
660            let entity = build_entity(&mut ModelContext::mutable(cx, slot.entity_id));
661            cx.entities.insert(slot, entity)
662        })
663    }
664
665    fn update_entity<T: Send + Sync + 'static, R>(
666        &mut self,
667        handle: &Handle<T>,
668        update: impl FnOnce(&mut T, &mut Self::EntityContext<'_, '_, T>) -> R,
669    ) -> R {
670        self.update(|cx| {
671            let mut entity = cx.entities.lease(handle);
672            let result = update(
673                &mut entity,
674                &mut ModelContext::mutable(cx, handle.entity_id),
675            );
676            cx.entities.end_lease(entity);
677            result
678        })
679    }
680}
681
682impl<C> MainThread<C>
683where
684    C: Borrow<AppContext>,
685{
686    pub(crate) fn platform(&self) -> &dyn Platform {
687        self.0.borrow().platform.borrow_on_main_thread()
688    }
689
690    pub fn activate(&self, ignoring_other_apps: bool) {
691        self.platform().activate(ignoring_other_apps);
692    }
693
694    pub fn write_to_clipboard(&self, item: ClipboardItem) {
695        self.platform().write_to_clipboard(item)
696    }
697
698    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
699        self.platform().read_from_clipboard()
700    }
701
702    pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
703        self.platform().write_credentials(url, username, password)
704    }
705
706    pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
707        self.platform().read_credentials(url)
708    }
709
710    pub fn delete_credentials(&self, url: &str) -> Result<()> {
711        self.platform().delete_credentials(url)
712    }
713
714    pub fn open_url(&self, url: &str) {
715        self.platform().open_url(url);
716    }
717}
718
719impl MainThread<AppContext> {
720    fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
721        self.0.update(|cx| {
722            update(unsafe {
723                std::mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx)
724            })
725        })
726    }
727
728    pub(crate) fn update_window<R>(
729        &mut self,
730        id: WindowId,
731        update: impl FnOnce(&mut MainThread<WindowContext>) -> R,
732    ) -> Result<R> {
733        self.0.update_window(id, |cx| {
734            update(unsafe {
735                std::mem::transmute::<&mut WindowContext, &mut MainThread<WindowContext>>(cx)
736            })
737        })
738    }
739
740    pub fn open_window<S: 'static + Send + Sync>(
741        &mut self,
742        options: crate::WindowOptions,
743        build_root_view: impl FnOnce(&mut WindowContext) -> View<S> + Send + 'static,
744    ) -> WindowHandle<S> {
745        self.update(|cx| {
746            let id = cx.windows.insert(None);
747            let handle = WindowHandle::new(id);
748            let mut window = Window::new(handle.into(), options, cx);
749            let root_view = build_root_view(&mut WindowContext::mutable(cx, &mut window));
750            window.root_view.replace(root_view.into_any());
751            cx.windows.get_mut(id).unwrap().replace(window);
752            handle
753        })
754    }
755
756    pub fn update_global<G: 'static + Send + Sync, R>(
757        &mut self,
758        update: impl FnOnce(&mut G, &mut MainThread<AppContext>) -> R,
759    ) -> R {
760        self.0.update_global(|global, cx| {
761            let cx = unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) };
762            update(global, cx)
763        })
764    }
765}
766
767pub(crate) enum Effect {
768    Notify {
769        emitter: EntityId,
770    },
771    Emit {
772        emitter: EntityId,
773        event: Box<dyn Any + Send + Sync + 'static>,
774    },
775    FocusChanged {
776        window_id: WindowId,
777        focused: Option<FocusId>,
778    },
779    Refresh,
780    NotifyGlobalObservers {
781        global_type: TypeId,
782    },
783    Defer {
784        callback: Box<dyn FnOnce(&mut AppContext) + Send + Sync + 'static>,
785    },
786}
787
788pub(crate) struct AnyDrag {
789    pub drag_handle_view: AnyView,
790    pub cursor_offset: Point<Pixels>,
791    pub state: AnyBox,
792    pub state_type: TypeId,
793}
794
795#[cfg(test)]
796mod tests {
797    use super::AppContext;
798
799    #[test]
800    fn test_app_context_send_sync() {
801        // This will not compile if `AppContext` does not implement `Send`
802        fn assert_send<T: Send>() {}
803        assert_send::<AppContext>();
804    }
805}