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