1mod async_context;
2mod entity_map;
3mod model_context;
4#[cfg(any(test, feature = "test-support"))]
5mod test_context;
6
7pub use async_context::*;
8use derive_more::{Deref, DerefMut};
9pub use entity_map::*;
10pub use model_context::*;
11use refineable::Refineable;
12use smol::future::FutureExt;
13#[cfg(any(test, feature = "test-support"))]
14pub use test_context::*;
15use time::UtcOffset;
16
17use crate::{
18 current_platform, image_cache::ImageCache, init_app_menus, Action, ActionRegistry, Any,
19 AnyView, AnyWindowHandle, AppMetadata, AssetSource, BackgroundExecutor, ClipboardItem, Context,
20 DispatchPhase, DisplayId, Entity, EventEmitter, ForegroundExecutor, KeyBinding, Keymap,
21 Keystroke, LayoutId, Menu, PathPromptOptions, Pixels, Platform, PlatformDisplay, Point, Render,
22 SharedString, SubscriberSet, Subscription, SvgRenderer, Task, TextStyle, TextStyleRefinement,
23 TextSystem, View, ViewContext, Window, WindowContext, WindowHandle, WindowId,
24};
25use anyhow::{anyhow, Result};
26use collections::{FxHashMap, FxHashSet, VecDeque};
27use futures::{channel::oneshot, future::LocalBoxFuture, Future};
28use parking_lot::Mutex;
29use slotmap::SlotMap;
30use std::{
31 any::{type_name, TypeId},
32 cell::{Ref, RefCell, RefMut},
33 marker::PhantomData,
34 mem,
35 ops::{Deref, DerefMut},
36 path::{Path, PathBuf},
37 rc::{Rc, Weak},
38 sync::{atomic::Ordering::SeqCst, Arc},
39 time::Duration,
40};
41use util::{
42 http::{self, HttpClient},
43 ResultExt,
44};
45
46/// Temporary(?) wrapper around [`RefCell<AppContext>`] to help us debug any double borrows.
47/// Strongly consider removing after stabilization.
48pub struct AppCell {
49 app: RefCell<AppContext>,
50}
51
52impl AppCell {
53 #[track_caller]
54 pub fn borrow(&self) -> AppRef {
55 if option_env!("TRACK_THREAD_BORROWS").is_some() {
56 let thread_id = std::thread::current().id();
57 eprintln!("borrowed {thread_id:?}");
58 }
59 AppRef(self.app.borrow())
60 }
61
62 #[track_caller]
63 pub fn borrow_mut(&self) -> AppRefMut {
64 if option_env!("TRACK_THREAD_BORROWS").is_some() {
65 let thread_id = std::thread::current().id();
66 eprintln!("borrowed {thread_id:?}");
67 }
68 AppRefMut(self.app.borrow_mut())
69 }
70}
71
72#[derive(Deref, DerefMut)]
73pub struct AppRef<'a>(Ref<'a, AppContext>);
74
75impl<'a> Drop for AppRef<'a> {
76 fn drop(&mut self) {
77 if option_env!("TRACK_THREAD_BORROWS").is_some() {
78 let thread_id = std::thread::current().id();
79 eprintln!("dropped borrow from {thread_id:?}");
80 }
81 }
82}
83
84#[derive(Deref, DerefMut)]
85pub struct AppRefMut<'a>(RefMut<'a, AppContext>);
86
87impl<'a> Drop for AppRefMut<'a> {
88 fn drop(&mut self) {
89 if option_env!("TRACK_THREAD_BORROWS").is_some() {
90 let thread_id = std::thread::current().id();
91 eprintln!("dropped {thread_id:?}");
92 }
93 }
94}
95
96pub struct App(Rc<AppCell>);
97
98/// Represents an application before it is fully launched. Once your app is
99/// configured, you'll start the app with `App::run`.
100impl App {
101 /// Builds an app with the given asset source.
102 pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
103 Self(AppContext::new(
104 current_platform(),
105 asset_source,
106 http::client(),
107 ))
108 }
109
110 /// Start the application. The provided callback will be called once the
111 /// app is fully launched.
112 pub fn run<F>(self, on_finish_launching: F)
113 where
114 F: 'static + FnOnce(&mut AppContext),
115 {
116 let this = self.0.clone();
117 let platform = self.0.borrow().platform.clone();
118 platform.run(Box::new(move || {
119 let cx = &mut *this.borrow_mut();
120 on_finish_launching(cx);
121 }));
122 }
123
124 /// Register a handler to be invoked when the platform instructs the application
125 /// to open one or more URLs.
126 pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
127 where
128 F: 'static + FnMut(Vec<String>, &mut AppContext),
129 {
130 let this = Rc::downgrade(&self.0);
131 self.0.borrow().platform.on_open_urls(Box::new(move |urls| {
132 if let Some(app) = this.upgrade() {
133 callback(urls, &mut app.borrow_mut());
134 }
135 }));
136 self
137 }
138
139 pub fn on_reopen<F>(&self, mut callback: F) -> &Self
140 where
141 F: 'static + FnMut(&mut AppContext),
142 {
143 let this = Rc::downgrade(&self.0);
144 self.0.borrow_mut().platform.on_reopen(Box::new(move || {
145 if let Some(app) = this.upgrade() {
146 callback(&mut app.borrow_mut());
147 }
148 }));
149 self
150 }
151
152 pub fn metadata(&self) -> AppMetadata {
153 self.0.borrow().app_metadata.clone()
154 }
155
156 pub fn background_executor(&self) -> BackgroundExecutor {
157 self.0.borrow().background_executor.clone()
158 }
159
160 pub fn foreground_executor(&self) -> ForegroundExecutor {
161 self.0.borrow().foreground_executor.clone()
162 }
163
164 pub fn text_system(&self) -> Arc<TextSystem> {
165 self.0.borrow().text_system.clone()
166 }
167}
168
169pub(crate) type FrameCallback = Box<dyn FnOnce(&mut AppContext)>;
170type Handler = Box<dyn FnMut(&mut AppContext) -> bool + 'static>;
171type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + 'static>;
172type KeystrokeObserver = Box<dyn FnMut(&KeystrokeEvent, &mut WindowContext) + 'static>;
173type QuitHandler = Box<dyn FnOnce(&mut AppContext) -> LocalBoxFuture<'static, ()> + 'static>;
174type ReleaseListener = Box<dyn FnOnce(&mut dyn Any, &mut AppContext) + 'static>;
175type NewViewListener = Box<dyn FnMut(AnyView, &mut WindowContext) + 'static>;
176
177// struct FrameConsumer {
178// next_frame_callbacks: Vec<FrameCallback>,
179// task: Task<()>,
180// display_linker
181// }
182
183pub struct AppContext {
184 pub(crate) this: Weak<AppCell>,
185 pub(crate) platform: Rc<dyn Platform>,
186 app_metadata: AppMetadata,
187 text_system: Arc<TextSystem>,
188 flushing_effects: bool,
189 pending_updates: usize,
190 pub(crate) actions: Rc<ActionRegistry>,
191 pub(crate) active_drag: Option<AnyDrag>,
192 pub(crate) active_tooltip: Option<AnyTooltip>,
193 pub(crate) next_frame_callbacks: FxHashMap<DisplayId, Vec<FrameCallback>>,
194 pub(crate) frame_consumers: FxHashMap<DisplayId, Task<()>>,
195 pub(crate) background_executor: BackgroundExecutor,
196 pub(crate) foreground_executor: ForegroundExecutor,
197 pub(crate) svg_renderer: SvgRenderer,
198 asset_source: Arc<dyn AssetSource>,
199 pub(crate) image_cache: ImageCache,
200 pub(crate) text_style_stack: Vec<TextStyleRefinement>,
201 pub(crate) globals_by_type: FxHashMap<TypeId, Box<dyn Any>>,
202 pub(crate) entities: EntityMap,
203 pub(crate) new_view_observers: SubscriberSet<TypeId, NewViewListener>,
204 pub(crate) windows: SlotMap<WindowId, Option<Window>>,
205 pub(crate) keymap: Arc<Mutex<Keymap>>,
206 pub(crate) global_action_listeners:
207 FxHashMap<TypeId, Vec<Rc<dyn Fn(&dyn Any, DispatchPhase, &mut Self)>>>,
208 pending_effects: VecDeque<Effect>,
209 pub(crate) pending_notifications: FxHashSet<EntityId>,
210 pub(crate) pending_global_notifications: FxHashSet<TypeId>,
211 pub(crate) observers: SubscriberSet<EntityId, Handler>,
212 // TypeId is the type of the event that the listener callback expects
213 pub(crate) event_listeners: SubscriberSet<EntityId, (TypeId, Listener)>,
214 pub(crate) keystroke_observers: SubscriberSet<(), KeystrokeObserver>,
215 pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
216 pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
217 pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
218 pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
219 pub(crate) propagate_event: bool,
220}
221
222impl AppContext {
223 pub(crate) fn new(
224 platform: Rc<dyn Platform>,
225 asset_source: Arc<dyn AssetSource>,
226 http_client: Arc<dyn HttpClient>,
227 ) -> Rc<AppCell> {
228 let executor = platform.background_executor();
229 let foreground_executor = platform.foreground_executor();
230 assert!(
231 executor.is_main_thread(),
232 "must construct App on main thread"
233 );
234
235 let text_system = Arc::new(TextSystem::new(platform.text_system()));
236 let entities = EntityMap::new();
237
238 let app_metadata = AppMetadata {
239 os_name: platform.os_name(),
240 os_version: platform.os_version().ok(),
241 app_version: platform.app_version().ok(),
242 };
243
244 let app = Rc::new_cyclic(|this| AppCell {
245 app: RefCell::new(AppContext {
246 this: this.clone(),
247 platform: platform.clone(),
248 app_metadata,
249 text_system,
250 actions: Rc::new(ActionRegistry::default()),
251 flushing_effects: false,
252 pending_updates: 0,
253 active_drag: None,
254 active_tooltip: None,
255 next_frame_callbacks: FxHashMap::default(),
256 frame_consumers: FxHashMap::default(),
257 background_executor: executor,
258 foreground_executor,
259 svg_renderer: SvgRenderer::new(asset_source.clone()),
260 asset_source,
261 image_cache: ImageCache::new(http_client),
262 text_style_stack: Vec::new(),
263 globals_by_type: FxHashMap::default(),
264 entities,
265 new_view_observers: SubscriberSet::new(),
266 windows: SlotMap::with_key(),
267 keymap: Arc::new(Mutex::new(Keymap::default())),
268 global_action_listeners: FxHashMap::default(),
269 pending_effects: VecDeque::new(),
270 pending_notifications: FxHashSet::default(),
271 pending_global_notifications: FxHashSet::default(),
272 observers: SubscriberSet::new(),
273 event_listeners: SubscriberSet::new(),
274 release_listeners: SubscriberSet::new(),
275 keystroke_observers: SubscriberSet::new(),
276 global_observers: SubscriberSet::new(),
277 quit_observers: SubscriberSet::new(),
278 layout_id_buffer: Default::default(),
279 propagate_event: true,
280 }),
281 });
282
283 init_app_menus(platform.as_ref(), &mut app.borrow_mut());
284
285 platform.on_quit(Box::new({
286 let cx = app.clone();
287 move || {
288 cx.borrow_mut().shutdown();
289 }
290 }));
291
292 app
293 }
294
295 /// Quit the application gracefully. Handlers registered with `ModelContext::on_app_quit`
296 /// will be given 100ms to complete before exiting.
297 pub fn shutdown(&mut self) {
298 let mut futures = Vec::new();
299
300 for observer in self.quit_observers.remove(&()) {
301 futures.push(observer(self));
302 }
303
304 self.windows.clear();
305 self.flush_effects();
306
307 let futures = futures::future::join_all(futures);
308 if self
309 .background_executor
310 .block_with_timeout(Duration::from_millis(100), futures)
311 .is_err()
312 {
313 log::error!("timed out waiting on app_will_quit");
314 }
315 }
316
317 pub fn quit(&mut self) {
318 self.platform.quit();
319 }
320
321 pub fn app_metadata(&self) -> AppMetadata {
322 self.app_metadata.clone()
323 }
324
325 /// Schedules all windows in the application to be redrawn. This can be called
326 /// multiple times in an update cycle and still result in a single redraw.
327 pub fn refresh(&mut self) {
328 self.pending_effects.push_back(Effect::Refresh);
329 }
330
331 pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
332 self.pending_updates += 1;
333 let result = update(self);
334 if !self.flushing_effects && self.pending_updates == 1 {
335 self.flushing_effects = true;
336 self.flush_effects();
337 self.flushing_effects = false;
338 }
339 self.pending_updates -= 1;
340 result
341 }
342
343 pub fn observe<W, E>(
344 &mut self,
345 entity: &E,
346 mut on_notify: impl FnMut(E, &mut AppContext) + 'static,
347 ) -> Subscription
348 where
349 W: 'static,
350 E: Entity<W>,
351 {
352 self.observe_internal(entity, move |e, cx| {
353 on_notify(e, cx);
354 true
355 })
356 }
357
358 pub fn observe_internal<W, E>(
359 &mut self,
360 entity: &E,
361 mut on_notify: impl FnMut(E, &mut AppContext) -> bool + 'static,
362 ) -> Subscription
363 where
364 W: 'static,
365 E: Entity<W>,
366 {
367 let entity_id = entity.entity_id();
368 let handle = entity.downgrade();
369 let (subscription, activate) = self.observers.insert(
370 entity_id,
371 Box::new(move |cx| {
372 if let Some(handle) = E::upgrade_from(&handle) {
373 on_notify(handle, cx)
374 } else {
375 false
376 }
377 }),
378 );
379 self.defer(move |_| activate());
380 subscription
381 }
382
383 pub fn subscribe<T, E, Evt>(
384 &mut self,
385 entity: &E,
386 mut on_event: impl FnMut(E, &Evt, &mut AppContext) + 'static,
387 ) -> Subscription
388 where
389 T: 'static + EventEmitter<Evt>,
390 E: Entity<T>,
391 Evt: 'static,
392 {
393 self.subscribe_internal(entity, move |entity, event, cx| {
394 on_event(entity, event, cx);
395 true
396 })
397 }
398
399 pub(crate) fn subscribe_internal<T, E, Evt>(
400 &mut self,
401 entity: &E,
402 mut on_event: impl FnMut(E, &Evt, &mut AppContext) -> bool + 'static,
403 ) -> Subscription
404 where
405 T: 'static + EventEmitter<Evt>,
406 E: Entity<T>,
407 Evt: 'static,
408 {
409 let entity_id = entity.entity_id();
410 let entity = entity.downgrade();
411 let (subscription, activate) = self.event_listeners.insert(
412 entity_id,
413 (
414 TypeId::of::<Evt>(),
415 Box::new(move |event, cx| {
416 let event: &Evt = event.downcast_ref().expect("invalid event type");
417 if let Some(handle) = E::upgrade_from(&entity) {
418 on_event(handle, event, cx)
419 } else {
420 false
421 }
422 }),
423 ),
424 );
425 self.defer(move |_| activate());
426 subscription
427 }
428
429 pub fn windows(&self) -> Vec<AnyWindowHandle> {
430 self.windows
431 .values()
432 .filter_map(|window| Some(window.as_ref()?.handle))
433 .collect()
434 }
435
436 pub fn active_window(&self) -> Option<AnyWindowHandle> {
437 self.platform.active_window()
438 }
439
440 /// Opens a new window with the given option and the root view returned by the given function.
441 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
442 /// functionality.
443 pub fn open_window<V: 'static + Render>(
444 &mut self,
445 options: crate::WindowOptions,
446 build_root_view: impl FnOnce(&mut WindowContext) -> View<V>,
447 ) -> WindowHandle<V> {
448 self.update(|cx| {
449 let id = cx.windows.insert(None);
450 let handle = WindowHandle::new(id);
451 let mut window = Window::new(handle.into(), options, cx);
452 let root_view = build_root_view(&mut WindowContext::new(cx, &mut window));
453 window.root_view.replace(root_view.into());
454 cx.windows.get_mut(id).unwrap().replace(window);
455 handle
456 })
457 }
458
459 /// Instructs the platform to activate the application by bringing it to the foreground.
460 pub fn activate(&self, ignoring_other_apps: bool) {
461 self.platform.activate(ignoring_other_apps);
462 }
463
464 pub fn hide(&self) {
465 self.platform.hide();
466 }
467
468 pub fn hide_other_apps(&self) {
469 self.platform.hide_other_apps();
470 }
471
472 pub fn unhide_other_apps(&self) {
473 self.platform.unhide_other_apps();
474 }
475
476 /// Returns the list of currently active displays.
477 pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
478 self.platform.displays()
479 }
480
481 /// Writes data to the platform clipboard.
482 pub fn write_to_clipboard(&self, item: ClipboardItem) {
483 self.platform.write_to_clipboard(item)
484 }
485
486 /// Reads data from the platform clipboard.
487 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
488 self.platform.read_from_clipboard()
489 }
490
491 /// Writes credentials to the platform keychain.
492 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
493 self.platform.write_credentials(url, username, password)
494 }
495
496 /// Reads credentials from the platform keychain.
497 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
498 self.platform.read_credentials(url)
499 }
500
501 /// Deletes credentials from the platform keychain.
502 pub fn delete_credentials(&self, url: &str) -> Result<()> {
503 self.platform.delete_credentials(url)
504 }
505
506 /// Directs the platform's default browser to open the given URL.
507 pub fn open_url(&self, url: &str) {
508 self.platform.open_url(url);
509 }
510
511 pub fn app_path(&self) -> Result<PathBuf> {
512 self.platform.app_path()
513 }
514
515 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
516 self.platform.path_for_auxiliary_executable(name)
517 }
518
519 pub fn double_click_interval(&self) -> Duration {
520 self.platform.double_click_interval()
521 }
522
523 pub fn prompt_for_paths(
524 &self,
525 options: PathPromptOptions,
526 ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
527 self.platform.prompt_for_paths(options)
528 }
529
530 pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
531 self.platform.prompt_for_new_path(directory)
532 }
533
534 pub fn reveal_path(&self, path: &Path) {
535 self.platform.reveal_path(path)
536 }
537
538 pub fn should_auto_hide_scrollbars(&self) -> bool {
539 self.platform.should_auto_hide_scrollbars()
540 }
541
542 pub fn restart(&self) {
543 self.platform.restart()
544 }
545
546 pub fn local_timezone(&self) -> UtcOffset {
547 self.platform.local_timezone()
548 }
549
550 pub(crate) fn push_effect(&mut self, effect: Effect) {
551 match &effect {
552 Effect::Notify { emitter } => {
553 if !self.pending_notifications.insert(*emitter) {
554 return;
555 }
556 }
557 Effect::NotifyGlobalObservers { global_type } => {
558 if !self.pending_global_notifications.insert(*global_type) {
559 return;
560 }
561 }
562 _ => {}
563 };
564
565 self.pending_effects.push_back(effect);
566 }
567
568 /// Called at the end of AppContext::update to complete any side effects
569 /// such as notifying observers, emitting events, etc. Effects can themselves
570 /// cause effects, so we continue looping until all effects are processed.
571 fn flush_effects(&mut self) {
572 loop {
573 self.release_dropped_entities();
574 self.release_dropped_focus_handles();
575
576 if let Some(effect) = self.pending_effects.pop_front() {
577 match effect {
578 Effect::Notify { emitter } => {
579 self.apply_notify_effect(emitter);
580 }
581
582 Effect::Emit {
583 emitter,
584 event_type,
585 event,
586 } => self.apply_emit_effect(emitter, event_type, event),
587
588 Effect::Refresh => {
589 self.apply_refresh_effect();
590 }
591
592 Effect::NotifyGlobalObservers { global_type } => {
593 self.apply_notify_global_observers_effect(global_type);
594 }
595
596 Effect::Defer { callback } => {
597 self.apply_defer_effect(callback);
598 }
599 }
600 } else {
601 for window in self.windows.values() {
602 if let Some(window) = window.as_ref() {
603 if window.dirty {
604 window.platform_window.invalidate();
605 }
606 }
607 }
608
609 #[cfg(any(test, feature = "test-support"))]
610 for window in self
611 .windows
612 .values()
613 .filter_map(|window| {
614 let window = window.as_ref()?;
615 (window.dirty || window.focus_invalidated).then_some(window.handle)
616 })
617 .collect::<Vec<_>>()
618 {
619 self.update_window(window, |_, cx| cx.draw()).unwrap();
620 }
621
622 if self.pending_effects.is_empty() {
623 break;
624 }
625 }
626 }
627 }
628
629 /// Repeatedly called during `flush_effects` to release any entities whose
630 /// reference count has become zero. We invoke any release observers before dropping
631 /// each entity.
632 fn release_dropped_entities(&mut self) {
633 loop {
634 let dropped = self.entities.take_dropped();
635 if dropped.is_empty() {
636 break;
637 }
638
639 for (entity_id, mut entity) in dropped {
640 self.observers.remove(&entity_id);
641 self.event_listeners.remove(&entity_id);
642 for release_callback in self.release_listeners.remove(&entity_id) {
643 release_callback(entity.as_mut(), self);
644 }
645 }
646 }
647 }
648
649 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
650 fn release_dropped_focus_handles(&mut self) {
651 for window_handle in self.windows() {
652 window_handle
653 .update(self, |_, cx| {
654 let mut blur_window = false;
655 let focus = cx.window.focus;
656 cx.window.focus_handles.write().retain(|handle_id, count| {
657 if count.load(SeqCst) == 0 {
658 if focus == Some(handle_id) {
659 blur_window = true;
660 }
661 false
662 } else {
663 true
664 }
665 });
666
667 if blur_window {
668 cx.blur();
669 }
670 })
671 .unwrap();
672 }
673 }
674
675 fn apply_notify_effect(&mut self, emitter: EntityId) {
676 self.pending_notifications.remove(&emitter);
677
678 self.observers
679 .clone()
680 .retain(&emitter, |handler| handler(self));
681 }
682
683 fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: Box<dyn Any>) {
684 self.event_listeners
685 .clone()
686 .retain(&emitter, |(stored_type, handler)| {
687 if *stored_type == event_type {
688 handler(event.as_ref(), self)
689 } else {
690 true
691 }
692 });
693 }
694
695 fn apply_refresh_effect(&mut self) {
696 for window in self.windows.values_mut() {
697 if let Some(window) = window.as_mut() {
698 window.dirty = true;
699 }
700 }
701 }
702
703 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
704 self.pending_global_notifications.remove(&type_id);
705 self.global_observers
706 .clone()
707 .retain(&type_id, |observer| observer(self));
708 }
709
710 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
711 callback(self);
712 }
713
714 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
715 /// so it can be held across `await` points.
716 pub fn to_async(&self) -> AsyncAppContext {
717 AsyncAppContext {
718 app: unsafe { mem::transmute(self.this.clone()) },
719 background_executor: self.background_executor.clone(),
720 foreground_executor: self.foreground_executor.clone(),
721 }
722 }
723
724 /// Obtains a reference to the executor, which can be used to spawn futures.
725 pub fn background_executor(&self) -> &BackgroundExecutor {
726 &self.background_executor
727 }
728
729 /// Obtains a reference to the executor, which can be used to spawn futures.
730 pub fn foreground_executor(&self) -> &ForegroundExecutor {
731 &self.foreground_executor
732 }
733
734 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
735 /// with AsyncAppContext, which allows the application state to be accessed across await points.
736 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
737 where
738 Fut: Future<Output = R> + 'static,
739 R: 'static,
740 {
741 self.foreground_executor.spawn(f(self.to_async()))
742 }
743
744 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
745 /// that are currently on the stack to be returned to the app.
746 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
747 self.push_effect(Effect::Defer {
748 callback: Box::new(f),
749 });
750 }
751
752 /// Accessor for the application's asset source, which is provided when constructing the `App`.
753 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
754 &self.asset_source
755 }
756
757 /// Accessor for the text system.
758 pub fn text_system(&self) -> &Arc<TextSystem> {
759 &self.text_system
760 }
761
762 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
763 pub fn text_style(&self) -> TextStyle {
764 let mut style = TextStyle::default();
765 for refinement in &self.text_style_stack {
766 style.refine(refinement);
767 }
768 style
769 }
770
771 /// Check whether a global of the given type has been assigned.
772 pub fn has_global<G: 'static>(&self) -> bool {
773 self.globals_by_type.contains_key(&TypeId::of::<G>())
774 }
775
776 /// Access the global of the given type. Panics if a global for that type has not been assigned.
777 #[track_caller]
778 pub fn global<G: 'static>(&self) -> &G {
779 self.globals_by_type
780 .get(&TypeId::of::<G>())
781 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
782 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
783 .unwrap()
784 }
785
786 /// Access the global of the given type if a value has been assigned.
787 pub fn try_global<G: 'static>(&self) -> Option<&G> {
788 self.globals_by_type
789 .get(&TypeId::of::<G>())
790 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
791 }
792
793 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
794 #[track_caller]
795 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
796 let global_type = TypeId::of::<G>();
797 self.push_effect(Effect::NotifyGlobalObservers { global_type });
798 self.globals_by_type
799 .get_mut(&global_type)
800 .and_then(|any_state| any_state.downcast_mut::<G>())
801 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
802 .unwrap()
803 }
804
805 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
806 /// yet been assigned.
807 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
808 let global_type = TypeId::of::<G>();
809 self.push_effect(Effect::NotifyGlobalObservers { global_type });
810 self.globals_by_type
811 .entry(global_type)
812 .or_insert_with(|| Box::<G>::default())
813 .downcast_mut::<G>()
814 .unwrap()
815 }
816
817 /// Set the value of the global of the given type.
818 pub fn set_global<G: Any>(&mut self, global: G) {
819 let global_type = TypeId::of::<G>();
820 self.push_effect(Effect::NotifyGlobalObservers { global_type });
821 self.globals_by_type.insert(global_type, Box::new(global));
822 }
823
824 /// Clear all stored globals. Does not notify global observers.
825 #[cfg(any(test, feature = "test-support"))]
826 pub fn clear_globals(&mut self) {
827 self.globals_by_type.drain();
828 }
829
830 /// Remove the global of the given type from the app context. Does not notify global observers.
831 pub fn remove_global<G: Any>(&mut self) -> G {
832 let global_type = TypeId::of::<G>();
833 *self
834 .globals_by_type
835 .remove(&global_type)
836 .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
837 .downcast()
838 .unwrap()
839 }
840
841 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
842 /// your closure with mutable access to the `AppContext` and the global simultaneously.
843 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
844 self.update(|cx| {
845 let mut global = cx.lease_global::<G>();
846 let result = f(&mut global, cx);
847 cx.end_global_lease(global);
848 result
849 })
850 }
851
852 /// Register a callback to be invoked when a global of the given type is updated.
853 pub fn observe_global<G: 'static>(
854 &mut self,
855 mut f: impl FnMut(&mut Self) + 'static,
856 ) -> Subscription {
857 let (subscription, activate) = self.global_observers.insert(
858 TypeId::of::<G>(),
859 Box::new(move |cx| {
860 f(cx);
861 true
862 }),
863 );
864 self.defer(move |_| activate());
865 subscription
866 }
867
868 /// Move the global of the given type to the stack.
869 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
870 GlobalLease::new(
871 self.globals_by_type
872 .remove(&TypeId::of::<G>())
873 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
874 .unwrap(),
875 )
876 }
877
878 /// Restore the global of the given type after it is moved to the stack.
879 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
880 let global_type = TypeId::of::<G>();
881 self.push_effect(Effect::NotifyGlobalObservers { global_type });
882 self.globals_by_type.insert(global_type, lease.global);
883 }
884
885 pub fn observe_new_views<V: 'static>(
886 &mut self,
887 on_new: impl 'static + Fn(&mut V, &mut ViewContext<V>),
888 ) -> Subscription {
889 let (subscription, activate) = self.new_view_observers.insert(
890 TypeId::of::<V>(),
891 Box::new(move |any_view: AnyView, cx: &mut WindowContext| {
892 any_view
893 .downcast::<V>()
894 .unwrap()
895 .update(cx, |view_state, cx| {
896 on_new(view_state, cx);
897 })
898 }),
899 );
900 activate();
901 subscription
902 }
903
904 pub fn observe_release<E, T>(
905 &mut self,
906 handle: &E,
907 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
908 ) -> Subscription
909 where
910 E: Entity<T>,
911 T: 'static,
912 {
913 let (subscription, activate) = self.release_listeners.insert(
914 handle.entity_id(),
915 Box::new(move |entity, cx| {
916 let entity = entity.downcast_mut().expect("invalid entity type");
917 on_release(entity, cx)
918 }),
919 );
920 activate();
921 subscription
922 }
923
924 pub fn observe_keystrokes(
925 &mut self,
926 f: impl FnMut(&KeystrokeEvent, &mut WindowContext) + 'static,
927 ) -> Subscription {
928 let (subscription, activate) = self.keystroke_observers.insert((), Box::new(f));
929 activate();
930 subscription
931 }
932
933 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
934 self.text_style_stack.push(text_style);
935 }
936
937 pub(crate) fn pop_text_style(&mut self) {
938 self.text_style_stack.pop();
939 }
940
941 /// Register key bindings.
942 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
943 self.keymap.lock().add_bindings(bindings);
944 self.pending_effects.push_back(Effect::Refresh);
945 }
946
947 pub fn clear_key_bindings(&mut self) {
948 self.keymap.lock().clear();
949 self.pending_effects.push_back(Effect::Refresh);
950 }
951
952 /// Register a global listener for actions invoked via the keyboard.
953 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
954 self.global_action_listeners
955 .entry(TypeId::of::<A>())
956 .or_default()
957 .push(Rc::new(move |action, phase, cx| {
958 if phase == DispatchPhase::Bubble {
959 let action = action.downcast_ref().unwrap();
960 listener(action, cx)
961 }
962 }));
963 }
964
965 /// Event handlers propagate events by default. Call this method to stop dispatching to
966 /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
967 /// the opposite of [`Self::propagate`]. It's also possible to cancel a call to [`Self::propagate`] by
968 /// calling this method before effects are flushed.
969 pub fn stop_propagation(&mut self) {
970 self.propagate_event = false;
971 }
972
973 /// Action handlers stop propagation by default during the bubble phase of action dispatch
974 /// dispatching to action handlers higher in the element tree. This is the opposite of
975 /// [`Self::stop_propagation`]. It's also possible to cancel a call to [`Self::stop_propagation`] by calling
976 /// this method before effects are flushed.
977 pub fn propagate(&mut self) {
978 self.propagate_event = true;
979 }
980
981 pub fn build_action(
982 &self,
983 name: &str,
984 data: Option<serde_json::Value>,
985 ) -> Result<Box<dyn Action>> {
986 self.actions.build_action(name, data)
987 }
988
989 pub fn all_action_names(&self) -> &[SharedString] {
990 self.actions.all_action_names()
991 }
992
993 pub fn on_app_quit<Fut>(
994 &mut self,
995 mut on_quit: impl FnMut(&mut AppContext) -> Fut + 'static,
996 ) -> Subscription
997 where
998 Fut: 'static + Future<Output = ()>,
999 {
1000 let (subscription, activate) = self.quit_observers.insert(
1001 (),
1002 Box::new(move |cx| {
1003 let future = on_quit(cx);
1004 future.boxed_local()
1005 }),
1006 );
1007 activate();
1008 subscription
1009 }
1010
1011 pub(crate) fn clear_pending_keystrokes(&mut self) {
1012 for window in self.windows() {
1013 window
1014 .update(self, |_, cx| {
1015 cx.window
1016 .rendered_frame
1017 .dispatch_tree
1018 .clear_pending_keystrokes();
1019 cx.window
1020 .next_frame
1021 .dispatch_tree
1022 .clear_pending_keystrokes();
1023 })
1024 .ok();
1025 }
1026 }
1027
1028 pub fn is_action_available(&mut self, action: &dyn Action) -> bool {
1029 if let Some(window) = self.active_window() {
1030 if let Ok(window_action_available) =
1031 window.update(self, |_, cx| cx.is_action_available(action))
1032 {
1033 return window_action_available;
1034 }
1035 }
1036
1037 self.global_action_listeners
1038 .contains_key(&action.as_any().type_id())
1039 }
1040
1041 pub fn set_menus(&mut self, menus: Vec<Menu>) {
1042 self.platform.set_menus(menus, &self.keymap.lock());
1043 }
1044
1045 pub fn dispatch_action(&mut self, action: &dyn Action) {
1046 if let Some(active_window) = self.active_window() {
1047 active_window
1048 .update(self, |_, cx| cx.dispatch_action(action.boxed_clone()))
1049 .log_err();
1050 } else {
1051 self.propagate_event = true;
1052
1053 if let Some(mut global_listeners) = self
1054 .global_action_listeners
1055 .remove(&action.as_any().type_id())
1056 {
1057 for listener in &global_listeners {
1058 listener(action.as_any(), DispatchPhase::Capture, self);
1059 if !self.propagate_event {
1060 break;
1061 }
1062 }
1063
1064 global_listeners.extend(
1065 self.global_action_listeners
1066 .remove(&action.as_any().type_id())
1067 .unwrap_or_default(),
1068 );
1069
1070 self.global_action_listeners
1071 .insert(action.as_any().type_id(), global_listeners);
1072 }
1073
1074 if self.propagate_event {
1075 if let Some(mut global_listeners) = self
1076 .global_action_listeners
1077 .remove(&action.as_any().type_id())
1078 {
1079 for listener in global_listeners.iter().rev() {
1080 listener(action.as_any(), DispatchPhase::Bubble, self);
1081 if !self.propagate_event {
1082 break;
1083 }
1084 }
1085
1086 global_listeners.extend(
1087 self.global_action_listeners
1088 .remove(&action.as_any().type_id())
1089 .unwrap_or_default(),
1090 );
1091
1092 self.global_action_listeners
1093 .insert(action.as_any().type_id(), global_listeners);
1094 }
1095 }
1096 }
1097 }
1098
1099 pub fn has_active_drag(&self) -> bool {
1100 self.active_drag.is_some()
1101 }
1102}
1103
1104impl Context for AppContext {
1105 type Result<T> = T;
1106
1107 /// Build an entity that is owned by the application. The given function will be invoked with
1108 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
1109 /// which can be used to access the entity in a context.
1110 fn new_model<T: 'static>(
1111 &mut self,
1112 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1113 ) -> Model<T> {
1114 self.update(|cx| {
1115 let slot = cx.entities.reserve();
1116 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
1117 cx.entities.insert(slot, entity)
1118 })
1119 }
1120
1121 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
1122 /// entity along with a `ModelContext` for the entity.
1123 fn update_model<T: 'static, R>(
1124 &mut self,
1125 model: &Model<T>,
1126 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1127 ) -> R {
1128 self.update(|cx| {
1129 let mut entity = cx.entities.lease(model);
1130 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
1131 cx.entities.end_lease(entity);
1132 result
1133 })
1134 }
1135
1136 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
1137 where
1138 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1139 {
1140 self.update(|cx| {
1141 let mut window = cx
1142 .windows
1143 .get_mut(handle.id)
1144 .ok_or_else(|| anyhow!("window not found"))?
1145 .take()
1146 .unwrap();
1147
1148 let root_view = window.root_view.clone().unwrap();
1149 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
1150
1151 if window.removed {
1152 cx.windows.remove(handle.id);
1153 } else {
1154 cx.windows
1155 .get_mut(handle.id)
1156 .ok_or_else(|| anyhow!("window not found"))?
1157 .replace(window);
1158 }
1159
1160 Ok(result)
1161 })
1162 }
1163
1164 fn read_model<T, R>(
1165 &self,
1166 handle: &Model<T>,
1167 read: impl FnOnce(&T, &AppContext) -> R,
1168 ) -> Self::Result<R>
1169 where
1170 T: 'static,
1171 {
1172 let entity = self.entities.read(handle);
1173 read(entity, self)
1174 }
1175
1176 fn read_window<T, R>(
1177 &self,
1178 window: &WindowHandle<T>,
1179 read: impl FnOnce(View<T>, &AppContext) -> R,
1180 ) -> Result<R>
1181 where
1182 T: 'static,
1183 {
1184 let window = self
1185 .windows
1186 .get(window.id)
1187 .ok_or_else(|| anyhow!("window not found"))?
1188 .as_ref()
1189 .unwrap();
1190
1191 let root_view = window.root_view.clone().unwrap();
1192 let view = root_view
1193 .downcast::<T>()
1194 .map_err(|_| anyhow!("root view's type has changed"))?;
1195
1196 Ok(read(view, self))
1197 }
1198}
1199
1200/// These effects are processed at the end of each application update cycle.
1201pub(crate) enum Effect {
1202 Notify {
1203 emitter: EntityId,
1204 },
1205 Emit {
1206 emitter: EntityId,
1207 event_type: TypeId,
1208 event: Box<dyn Any>,
1209 },
1210 Refresh,
1211 NotifyGlobalObservers {
1212 global_type: TypeId,
1213 },
1214 Defer {
1215 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
1216 },
1217}
1218
1219/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
1220pub(crate) struct GlobalLease<G: 'static> {
1221 global: Box<dyn Any>,
1222 global_type: PhantomData<G>,
1223}
1224
1225impl<G: 'static> GlobalLease<G> {
1226 fn new(global: Box<dyn Any>) -> Self {
1227 GlobalLease {
1228 global,
1229 global_type: PhantomData,
1230 }
1231 }
1232}
1233
1234impl<G: 'static> Deref for GlobalLease<G> {
1235 type Target = G;
1236
1237 fn deref(&self) -> &Self::Target {
1238 self.global.downcast_ref().unwrap()
1239 }
1240}
1241
1242impl<G: 'static> DerefMut for GlobalLease<G> {
1243 fn deref_mut(&mut self) -> &mut Self::Target {
1244 self.global.downcast_mut().unwrap()
1245 }
1246}
1247
1248/// Contains state associated with an active drag operation, started by dragging an element
1249/// within the window or by dragging into the app from the underlying platform.
1250pub struct AnyDrag {
1251 pub view: AnyView,
1252 pub value: Box<dyn Any>,
1253 pub cursor_offset: Point<Pixels>,
1254}
1255
1256#[derive(Clone)]
1257pub(crate) struct AnyTooltip {
1258 pub view: AnyView,
1259 pub cursor_offset: Point<Pixels>,
1260}
1261
1262#[derive(Debug)]
1263pub struct KeystrokeEvent {
1264 pub keystroke: Keystroke,
1265 pub action: Option<Box<dyn Action>>,
1266}