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.
48#[doc(hidden)]
49pub struct AppCell {
50 app: RefCell<AppContext>,
51}
52
53impl AppCell {
54 #[doc(hidden)]
55 #[track_caller]
56 pub fn borrow(&self) -> AppRef {
57 if option_env!("TRACK_THREAD_BORROWS").is_some() {
58 let thread_id = std::thread::current().id();
59 eprintln!("borrowed {thread_id:?}");
60 }
61 AppRef(self.app.borrow())
62 }
63
64 #[doc(hidden)]
65 #[track_caller]
66 pub fn borrow_mut(&self) -> AppRefMut {
67 if option_env!("TRACK_THREAD_BORROWS").is_some() {
68 let thread_id = std::thread::current().id();
69 eprintln!("borrowed {thread_id:?}");
70 }
71 AppRefMut(self.app.borrow_mut())
72 }
73}
74
75#[doc(hidden)]
76#[derive(Deref, DerefMut)]
77pub struct AppRef<'a>(Ref<'a, AppContext>);
78
79impl<'a> Drop for AppRef<'a> {
80 fn drop(&mut self) {
81 if option_env!("TRACK_THREAD_BORROWS").is_some() {
82 let thread_id = std::thread::current().id();
83 eprintln!("dropped borrow from {thread_id:?}");
84 }
85 }
86}
87
88#[doc(hidden)]
89#[derive(Deref, DerefMut)]
90pub struct AppRefMut<'a>(RefMut<'a, AppContext>);
91
92impl<'a> Drop for AppRefMut<'a> {
93 fn drop(&mut self) {
94 if option_env!("TRACK_THREAD_BORROWS").is_some() {
95 let thread_id = std::thread::current().id();
96 eprintln!("dropped {thread_id:?}");
97 }
98 }
99}
100
101/// A reference to a GPUI application, typically constructed in the `main` function of your app.
102/// You won't interact with this type much outside of initial configuration and startup.
103pub struct App(Rc<AppCell>);
104
105/// Represents an application before it is fully launched. Once your app is
106/// configured, you'll start the app with `App::run`.
107impl App {
108 /// Builds an app with the given asset source.
109 pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
110 Self(AppContext::new(
111 current_platform(),
112 asset_source,
113 http::client(),
114 ))
115 }
116
117 /// Start the application. The provided callback will be called once the
118 /// app is fully launched.
119 pub fn run<F>(self, on_finish_launching: F)
120 where
121 F: 'static + FnOnce(&mut AppContext),
122 {
123 let this = self.0.clone();
124 let platform = self.0.borrow().platform.clone();
125 platform.run(Box::new(move || {
126 let cx = &mut *this.borrow_mut();
127 on_finish_launching(cx);
128 }));
129 }
130
131 /// Register a handler to be invoked when the platform instructs the application
132 /// to open one or more URLs.
133 pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
134 where
135 F: 'static + FnMut(Vec<String>, &mut AppContext),
136 {
137 let this = Rc::downgrade(&self.0);
138 self.0.borrow().platform.on_open_urls(Box::new(move |urls| {
139 if let Some(app) = this.upgrade() {
140 callback(urls, &mut app.borrow_mut());
141 }
142 }));
143 self
144 }
145
146 /// Invokes a handler when an already-running application is launched.
147 /// On macOS, this can occur when the application icon is double-clicked or the app is launched via the dock.
148 pub fn on_reopen<F>(&self, mut callback: F) -> &Self
149 where
150 F: 'static + FnMut(&mut AppContext),
151 {
152 let this = Rc::downgrade(&self.0);
153 self.0.borrow_mut().platform.on_reopen(Box::new(move || {
154 if let Some(app) = this.upgrade() {
155 callback(&mut app.borrow_mut());
156 }
157 }));
158 self
159 }
160
161 /// Returns metadata associated with the application
162 pub fn metadata(&self) -> AppMetadata {
163 self.0.borrow().app_metadata.clone()
164 }
165
166 /// Returns a handle to the [`BackgroundExecutor`] associated with this app, which can be used to spawn futures in the background.
167 pub fn background_executor(&self) -> BackgroundExecutor {
168 self.0.borrow().background_executor.clone()
169 }
170
171 /// Returns a handle to the [`ForegroundExecutor`] associated with this app, which can be used to spawn futures in the foreground.
172 pub fn foreground_executor(&self) -> ForegroundExecutor {
173 self.0.borrow().foreground_executor.clone()
174 }
175
176 /// Returns a reference to the [`TextSystem`] associated with this app.
177 pub fn text_system(&self) -> Arc<TextSystem> {
178 self.0.borrow().text_system.clone()
179 }
180}
181
182pub(crate) type FrameCallback = Box<dyn FnOnce(&mut AppContext)>;
183type Handler = Box<dyn FnMut(&mut AppContext) -> bool + 'static>;
184type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + 'static>;
185type KeystrokeObserver = Box<dyn FnMut(&KeystrokeEvent, &mut WindowContext) + 'static>;
186type QuitHandler = Box<dyn FnOnce(&mut AppContext) -> LocalBoxFuture<'static, ()> + 'static>;
187type ReleaseListener = Box<dyn FnOnce(&mut dyn Any, &mut AppContext) + 'static>;
188type NewViewListener = Box<dyn FnMut(AnyView, &mut WindowContext) + 'static>;
189
190pub struct AppContext {
191 pub(crate) this: Weak<AppCell>,
192 pub(crate) platform: Rc<dyn Platform>,
193 app_metadata: AppMetadata,
194 text_system: Arc<TextSystem>,
195 flushing_effects: bool,
196 pending_updates: usize,
197 pub(crate) actions: Rc<ActionRegistry>,
198 pub(crate) active_drag: Option<AnyDrag>,
199 pub(crate) next_frame_callbacks: FxHashMap<DisplayId, Vec<FrameCallback>>,
200 pub(crate) frame_consumers: FxHashMap<DisplayId, Task<()>>,
201 pub(crate) background_executor: BackgroundExecutor,
202 pub(crate) foreground_executor: ForegroundExecutor,
203 pub(crate) svg_renderer: SvgRenderer,
204 asset_source: Arc<dyn AssetSource>,
205 pub(crate) image_cache: ImageCache,
206 pub(crate) text_style_stack: Vec<TextStyleRefinement>,
207 pub(crate) globals_by_type: FxHashMap<TypeId, Box<dyn Any>>,
208 pub(crate) entities: EntityMap,
209 pub(crate) new_view_observers: SubscriberSet<TypeId, NewViewListener>,
210 pub(crate) windows: SlotMap<WindowId, Option<Window>>,
211 pub(crate) keymap: Arc<Mutex<Keymap>>,
212 pub(crate) global_action_listeners:
213 FxHashMap<TypeId, Vec<Rc<dyn Fn(&dyn Any, DispatchPhase, &mut Self)>>>,
214 pending_effects: VecDeque<Effect>,
215 pub(crate) pending_notifications: FxHashSet<EntityId>,
216 pub(crate) pending_global_notifications: FxHashSet<TypeId>,
217 pub(crate) observers: SubscriberSet<EntityId, Handler>,
218 // TypeId is the type of the event that the listener callback expects
219 pub(crate) event_listeners: SubscriberSet<EntityId, (TypeId, Listener)>,
220 pub(crate) keystroke_observers: SubscriberSet<(), KeystrokeObserver>,
221 pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
222 pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
223 pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
224 pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
225 pub(crate) propagate_event: bool,
226}
227
228impl AppContext {
229 pub(crate) fn new(
230 platform: Rc<dyn Platform>,
231 asset_source: Arc<dyn AssetSource>,
232 http_client: Arc<dyn HttpClient>,
233 ) -> Rc<AppCell> {
234 let executor = platform.background_executor();
235 let foreground_executor = platform.foreground_executor();
236 assert!(
237 executor.is_main_thread(),
238 "must construct App on main thread"
239 );
240
241 let text_system = Arc::new(TextSystem::new(platform.text_system()));
242 let entities = EntityMap::new();
243
244 let app_metadata = AppMetadata {
245 os_name: platform.os_name(),
246 os_version: platform.os_version().ok(),
247 app_version: platform.app_version().ok(),
248 };
249
250 let app = Rc::new_cyclic(|this| AppCell {
251 app: RefCell::new(AppContext {
252 this: this.clone(),
253 platform: platform.clone(),
254 app_metadata,
255 text_system,
256 actions: Rc::new(ActionRegistry::default()),
257 flushing_effects: false,
258 pending_updates: 0,
259 active_drag: None,
260 next_frame_callbacks: FxHashMap::default(),
261 frame_consumers: FxHashMap::default(),
262 background_executor: executor,
263 foreground_executor,
264 svg_renderer: SvgRenderer::new(asset_source.clone()),
265 asset_source,
266 image_cache: ImageCache::new(http_client),
267 text_style_stack: Vec::new(),
268 globals_by_type: FxHashMap::default(),
269 entities,
270 new_view_observers: SubscriberSet::new(),
271 windows: SlotMap::with_key(),
272 keymap: Arc::new(Mutex::new(Keymap::default())),
273 global_action_listeners: FxHashMap::default(),
274 pending_effects: VecDeque::new(),
275 pending_notifications: FxHashSet::default(),
276 pending_global_notifications: FxHashSet::default(),
277 observers: SubscriberSet::new(),
278 event_listeners: SubscriberSet::new(),
279 release_listeners: SubscriberSet::new(),
280 keystroke_observers: SubscriberSet::new(),
281 global_observers: SubscriberSet::new(),
282 quit_observers: SubscriberSet::new(),
283 layout_id_buffer: Default::default(),
284 propagate_event: true,
285 }),
286 });
287
288 init_app_menus(platform.as_ref(), &mut app.borrow_mut());
289
290 platform.on_quit(Box::new({
291 let cx = app.clone();
292 move || {
293 cx.borrow_mut().shutdown();
294 }
295 }));
296
297 app
298 }
299
300 /// Quit the application gracefully. Handlers registered with [`ModelContext::on_app_quit`]
301 /// will be given 100ms to complete before exiting.
302 pub fn shutdown(&mut self) {
303 let mut futures = Vec::new();
304
305 for observer in self.quit_observers.remove(&()) {
306 futures.push(observer(self));
307 }
308
309 self.windows.clear();
310 self.flush_effects();
311
312 let futures = futures::future::join_all(futures);
313 if self
314 .background_executor
315 .block_with_timeout(Duration::from_millis(100), futures)
316 .is_err()
317 {
318 log::error!("timed out waiting on app_will_quit");
319 }
320 }
321
322 /// Gracefully quit the application via the platform's standard routine.
323 pub fn quit(&mut self) {
324 self.platform.quit();
325 }
326
327 /// Get metadata about the app and platform.
328 pub fn app_metadata(&self) -> AppMetadata {
329 self.app_metadata.clone()
330 }
331
332 /// Schedules all windows in the application to be redrawn. This can be called
333 /// multiple times in an update cycle and still result in a single redraw.
334 pub fn refresh(&mut self) {
335 self.pending_effects.push_back(Effect::Refresh);
336 }
337
338 pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
339 self.pending_updates += 1;
340 let result = update(self);
341 if !self.flushing_effects && self.pending_updates == 1 {
342 self.flushing_effects = true;
343 self.flush_effects();
344 self.flushing_effects = false;
345 }
346 self.pending_updates -= 1;
347 result
348 }
349
350 /// Arrange a callback to be invoked when the given model or view calls `notify` on its respective context.
351 pub fn observe<W, E>(
352 &mut self,
353 entity: &E,
354 mut on_notify: impl FnMut(E, &mut AppContext) + 'static,
355 ) -> Subscription
356 where
357 W: 'static,
358 E: Entity<W>,
359 {
360 self.observe_internal(entity, move |e, cx| {
361 on_notify(e, cx);
362 true
363 })
364 }
365
366 pub(crate) fn observe_internal<W, E>(
367 &mut self,
368 entity: &E,
369 mut on_notify: impl FnMut(E, &mut AppContext) -> bool + 'static,
370 ) -> Subscription
371 where
372 W: 'static,
373 E: Entity<W>,
374 {
375 let entity_id = entity.entity_id();
376 let handle = entity.downgrade();
377 let (subscription, activate) = self.observers.insert(
378 entity_id,
379 Box::new(move |cx| {
380 if let Some(handle) = E::upgrade_from(&handle) {
381 on_notify(handle, cx)
382 } else {
383 false
384 }
385 }),
386 );
387 self.defer(move |_| activate());
388 subscription
389 }
390
391 /// Arrange for the given callback to be invoked whenever the given model or view emits an event of a given type.
392 /// The callback is provided a handle to the emitting entity and a reference to the emitted event.
393 pub fn subscribe<T, E, Event>(
394 &mut self,
395 entity: &E,
396 mut on_event: impl FnMut(E, &Event, &mut AppContext) + 'static,
397 ) -> Subscription
398 where
399 T: 'static + EventEmitter<Event>,
400 E: Entity<T>,
401 Event: 'static,
402 {
403 self.subscribe_internal(entity, move |entity, event, cx| {
404 on_event(entity, event, cx);
405 true
406 })
407 }
408
409 pub(crate) fn subscribe_internal<T, E, Evt>(
410 &mut self,
411 entity: &E,
412 mut on_event: impl FnMut(E, &Evt, &mut AppContext) -> bool + 'static,
413 ) -> Subscription
414 where
415 T: 'static + EventEmitter<Evt>,
416 E: Entity<T>,
417 Evt: 'static,
418 {
419 let entity_id = entity.entity_id();
420 let entity = entity.downgrade();
421 let (subscription, activate) = self.event_listeners.insert(
422 entity_id,
423 (
424 TypeId::of::<Evt>(),
425 Box::new(move |event, cx| {
426 let event: &Evt = event.downcast_ref().expect("invalid event type");
427 if let Some(handle) = E::upgrade_from(&entity) {
428 on_event(handle, event, cx)
429 } else {
430 false
431 }
432 }),
433 ),
434 );
435 self.defer(move |_| activate());
436 subscription
437 }
438
439 /// Returns handles to all open windows in the application.
440 /// Each handle could be downcast to a handle typed for the root view of that window.
441 /// To find all windows of a given type, you could filter on
442 pub fn windows(&self) -> Vec<AnyWindowHandle> {
443 self.windows
444 .values()
445 .filter_map(|window| Some(window.as_ref()?.handle))
446 .collect()
447 }
448
449 pub fn active_window(&self) -> Option<AnyWindowHandle> {
450 self.platform.active_window()
451 }
452
453 /// Opens a new window with the given option and the root view returned by the given function.
454 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
455 /// functionality.
456 pub fn open_window<V: 'static + Render>(
457 &mut self,
458 options: crate::WindowOptions,
459 build_root_view: impl FnOnce(&mut WindowContext) -> View<V>,
460 ) -> WindowHandle<V> {
461 self.update(|cx| {
462 let id = cx.windows.insert(None);
463 let handle = WindowHandle::new(id);
464 let mut window = Window::new(handle.into(), options, cx);
465 let root_view = build_root_view(&mut WindowContext::new(cx, &mut window));
466 window.root_view.replace(root_view.into());
467 cx.windows.get_mut(id).unwrap().replace(window);
468 handle
469 })
470 }
471
472 /// Instructs the platform to activate the application by bringing it to the foreground.
473 pub fn activate(&self, ignoring_other_apps: bool) {
474 self.platform.activate(ignoring_other_apps);
475 }
476
477 pub fn hide(&self) {
478 self.platform.hide();
479 }
480
481 pub fn hide_other_apps(&self) {
482 self.platform.hide_other_apps();
483 }
484
485 pub fn unhide_other_apps(&self) {
486 self.platform.unhide_other_apps();
487 }
488
489 /// Returns the list of currently active displays.
490 pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
491 self.platform.displays()
492 }
493
494 /// Writes data to the platform clipboard.
495 pub fn write_to_clipboard(&self, item: ClipboardItem) {
496 self.platform.write_to_clipboard(item)
497 }
498
499 /// Reads data from the platform clipboard.
500 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
501 self.platform.read_from_clipboard()
502 }
503
504 /// Writes credentials to the platform keychain.
505 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
506 self.platform.write_credentials(url, username, password)
507 }
508
509 /// Reads credentials from the platform keychain.
510 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
511 self.platform.read_credentials(url)
512 }
513
514 /// Deletes credentials from the platform keychain.
515 pub fn delete_credentials(&self, url: &str) -> Result<()> {
516 self.platform.delete_credentials(url)
517 }
518
519 /// Directs the platform's default browser to open the given URL.
520 pub fn open_url(&self, url: &str) {
521 self.platform.open_url(url);
522 }
523
524 pub fn app_path(&self) -> Result<PathBuf> {
525 self.platform.app_path()
526 }
527
528 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
529 self.platform.path_for_auxiliary_executable(name)
530 }
531
532 pub fn double_click_interval(&self) -> Duration {
533 self.platform.double_click_interval()
534 }
535
536 pub fn prompt_for_paths(
537 &self,
538 options: PathPromptOptions,
539 ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
540 self.platform.prompt_for_paths(options)
541 }
542
543 pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
544 self.platform.prompt_for_new_path(directory)
545 }
546
547 pub fn reveal_path(&self, path: &Path) {
548 self.platform.reveal_path(path)
549 }
550
551 pub fn should_auto_hide_scrollbars(&self) -> bool {
552 self.platform.should_auto_hide_scrollbars()
553 }
554
555 pub fn restart(&self) {
556 self.platform.restart()
557 }
558
559 pub fn local_timezone(&self) -> UtcOffset {
560 self.platform.local_timezone()
561 }
562
563 pub(crate) fn push_effect(&mut self, effect: Effect) {
564 match &effect {
565 Effect::Notify { emitter } => {
566 if !self.pending_notifications.insert(*emitter) {
567 return;
568 }
569 }
570 Effect::NotifyGlobalObservers { global_type } => {
571 if !self.pending_global_notifications.insert(*global_type) {
572 return;
573 }
574 }
575 _ => {}
576 };
577
578 self.pending_effects.push_back(effect);
579 }
580
581 /// Called at the end of [`AppContext::update`] to complete any side effects
582 /// such as notifying observers, emitting events, etc. Effects can themselves
583 /// cause effects, so we continue looping until all effects are processed.
584 fn flush_effects(&mut self) {
585 loop {
586 self.release_dropped_entities();
587 self.release_dropped_focus_handles();
588
589 if let Some(effect) = self.pending_effects.pop_front() {
590 match effect {
591 Effect::Notify { emitter } => {
592 self.apply_notify_effect(emitter);
593 }
594
595 Effect::Emit {
596 emitter,
597 event_type,
598 event,
599 } => self.apply_emit_effect(emitter, event_type, event),
600
601 Effect::Refresh => {
602 self.apply_refresh_effect();
603 }
604
605 Effect::NotifyGlobalObservers { global_type } => {
606 self.apply_notify_global_observers_effect(global_type);
607 }
608
609 Effect::Defer { callback } => {
610 self.apply_defer_effect(callback);
611 }
612 }
613 } else {
614 for window in self.windows.values() {
615 if let Some(window) = window.as_ref() {
616 if window.dirty {
617 window.platform_window.invalidate();
618 }
619 }
620 }
621
622 #[cfg(any(test, feature = "test-support"))]
623 for window in self
624 .windows
625 .values()
626 .filter_map(|window| {
627 let window = window.as_ref()?;
628 (window.dirty || window.focus_invalidated).then_some(window.handle)
629 })
630 .collect::<Vec<_>>()
631 {
632 self.update_window(window, |_, cx| cx.draw()).unwrap();
633 }
634
635 if self.pending_effects.is_empty() {
636 break;
637 }
638 }
639 }
640 }
641
642 /// Repeatedly called during `flush_effects` to release any entities whose
643 /// reference count has become zero. We invoke any release observers before dropping
644 /// each entity.
645 fn release_dropped_entities(&mut self) {
646 loop {
647 let dropped = self.entities.take_dropped();
648 if dropped.is_empty() {
649 break;
650 }
651
652 for (entity_id, mut entity) in dropped {
653 self.observers.remove(&entity_id);
654 self.event_listeners.remove(&entity_id);
655 for release_callback in self.release_listeners.remove(&entity_id) {
656 release_callback(entity.as_mut(), self);
657 }
658 }
659 }
660 }
661
662 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
663 fn release_dropped_focus_handles(&mut self) {
664 for window_handle in self.windows() {
665 window_handle
666 .update(self, |_, cx| {
667 let mut blur_window = false;
668 let focus = cx.window.focus;
669 cx.window.focus_handles.write().retain(|handle_id, count| {
670 if count.load(SeqCst) == 0 {
671 if focus == Some(handle_id) {
672 blur_window = true;
673 }
674 false
675 } else {
676 true
677 }
678 });
679
680 if blur_window {
681 cx.blur();
682 }
683 })
684 .unwrap();
685 }
686 }
687
688 fn apply_notify_effect(&mut self, emitter: EntityId) {
689 self.pending_notifications.remove(&emitter);
690
691 self.observers
692 .clone()
693 .retain(&emitter, |handler| handler(self));
694 }
695
696 fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: Box<dyn Any>) {
697 self.event_listeners
698 .clone()
699 .retain(&emitter, |(stored_type, handler)| {
700 if *stored_type == event_type {
701 handler(event.as_ref(), self)
702 } else {
703 true
704 }
705 });
706 }
707
708 fn apply_refresh_effect(&mut self) {
709 for window in self.windows.values_mut() {
710 if let Some(window) = window.as_mut() {
711 window.dirty = true;
712 }
713 }
714 }
715
716 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
717 self.pending_global_notifications.remove(&type_id);
718 self.global_observers
719 .clone()
720 .retain(&type_id, |observer| observer(self));
721 }
722
723 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
724 callback(self);
725 }
726
727 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
728 /// so it can be held across `await` points.
729 pub fn to_async(&self) -> AsyncAppContext {
730 AsyncAppContext {
731 app: unsafe { mem::transmute(self.this.clone()) },
732 background_executor: self.background_executor.clone(),
733 foreground_executor: self.foreground_executor.clone(),
734 }
735 }
736
737 /// Obtains a reference to the executor, which can be used to spawn futures.
738 pub fn background_executor(&self) -> &BackgroundExecutor {
739 &self.background_executor
740 }
741
742 /// Obtains a reference to the executor, which can be used to spawn futures.
743 pub fn foreground_executor(&self) -> &ForegroundExecutor {
744 &self.foreground_executor
745 }
746
747 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
748 /// with AsyncAppContext, which allows the application state to be accessed across await points.
749 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
750 where
751 Fut: Future<Output = R> + 'static,
752 R: 'static,
753 {
754 self.foreground_executor.spawn(f(self.to_async()))
755 }
756
757 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
758 /// that are currently on the stack to be returned to the app.
759 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
760 self.push_effect(Effect::Defer {
761 callback: Box::new(f),
762 });
763 }
764
765 /// Accessor for the application's asset source, which is provided when constructing the `App`.
766 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
767 &self.asset_source
768 }
769
770 /// Accessor for the text system.
771 pub fn text_system(&self) -> &Arc<TextSystem> {
772 &self.text_system
773 }
774
775 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
776 pub fn text_style(&self) -> TextStyle {
777 let mut style = TextStyle::default();
778 for refinement in &self.text_style_stack {
779 style.refine(refinement);
780 }
781 style
782 }
783
784 /// Check whether a global of the given type has been assigned.
785 pub fn has_global<G: 'static>(&self) -> bool {
786 self.globals_by_type.contains_key(&TypeId::of::<G>())
787 }
788
789 /// Access the global of the given type. Panics if a global for that type has not been assigned.
790 #[track_caller]
791 pub fn global<G: 'static>(&self) -> &G {
792 self.globals_by_type
793 .get(&TypeId::of::<G>())
794 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
795 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
796 .unwrap()
797 }
798
799 /// Access the global of the given type if a value has been assigned.
800 pub fn try_global<G: 'static>(&self) -> Option<&G> {
801 self.globals_by_type
802 .get(&TypeId::of::<G>())
803 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
804 }
805
806 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
807 #[track_caller]
808 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
809 let global_type = TypeId::of::<G>();
810 self.push_effect(Effect::NotifyGlobalObservers { global_type });
811 self.globals_by_type
812 .get_mut(&global_type)
813 .and_then(|any_state| any_state.downcast_mut::<G>())
814 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
815 .unwrap()
816 }
817
818 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
819 /// yet been assigned.
820 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
821 let global_type = TypeId::of::<G>();
822 self.push_effect(Effect::NotifyGlobalObservers { global_type });
823 self.globals_by_type
824 .entry(global_type)
825 .or_insert_with(|| Box::<G>::default())
826 .downcast_mut::<G>()
827 .unwrap()
828 }
829
830 /// Set the value of the global of the given type.
831 pub fn set_global<G: Any>(&mut self, global: G) {
832 let global_type = TypeId::of::<G>();
833 self.push_effect(Effect::NotifyGlobalObservers { global_type });
834 self.globals_by_type.insert(global_type, Box::new(global));
835 }
836
837 /// Clear all stored globals. Does not notify global observers.
838 #[cfg(any(test, feature = "test-support"))]
839 pub fn clear_globals(&mut self) {
840 self.globals_by_type.drain();
841 }
842
843 /// Remove the global of the given type from the app context. Does not notify global observers.
844 pub fn remove_global<G: Any>(&mut self) -> G {
845 let global_type = TypeId::of::<G>();
846 *self
847 .globals_by_type
848 .remove(&global_type)
849 .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
850 .downcast()
851 .unwrap()
852 }
853
854 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
855 /// your closure with mutable access to the `AppContext` and the global simultaneously.
856 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
857 self.update(|cx| {
858 let mut global = cx.lease_global::<G>();
859 let result = f(&mut global, cx);
860 cx.end_global_lease(global);
861 result
862 })
863 }
864
865 /// Register a callback to be invoked when a global of the given type is updated.
866 pub fn observe_global<G: 'static>(
867 &mut self,
868 mut f: impl FnMut(&mut Self) + 'static,
869 ) -> Subscription {
870 let (subscription, activate) = self.global_observers.insert(
871 TypeId::of::<G>(),
872 Box::new(move |cx| {
873 f(cx);
874 true
875 }),
876 );
877 self.defer(move |_| activate());
878 subscription
879 }
880
881 /// Move the global of the given type to the stack.
882 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
883 GlobalLease::new(
884 self.globals_by_type
885 .remove(&TypeId::of::<G>())
886 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
887 .unwrap(),
888 )
889 }
890
891 /// Restore the global of the given type after it is moved to the stack.
892 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
893 let global_type = TypeId::of::<G>();
894 self.push_effect(Effect::NotifyGlobalObservers { global_type });
895 self.globals_by_type.insert(global_type, lease.global);
896 }
897
898 pub fn observe_new_views<V: 'static>(
899 &mut self,
900 on_new: impl 'static + Fn(&mut V, &mut ViewContext<V>),
901 ) -> Subscription {
902 let (subscription, activate) = self.new_view_observers.insert(
903 TypeId::of::<V>(),
904 Box::new(move |any_view: AnyView, cx: &mut WindowContext| {
905 any_view
906 .downcast::<V>()
907 .unwrap()
908 .update(cx, |view_state, cx| {
909 on_new(view_state, cx);
910 })
911 }),
912 );
913 activate();
914 subscription
915 }
916
917 pub fn observe_release<E, T>(
918 &mut self,
919 handle: &E,
920 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
921 ) -> Subscription
922 where
923 E: Entity<T>,
924 T: 'static,
925 {
926 let (subscription, activate) = self.release_listeners.insert(
927 handle.entity_id(),
928 Box::new(move |entity, cx| {
929 let entity = entity.downcast_mut().expect("invalid entity type");
930 on_release(entity, cx)
931 }),
932 );
933 activate();
934 subscription
935 }
936
937 pub fn observe_keystrokes(
938 &mut self,
939 f: impl FnMut(&KeystrokeEvent, &mut WindowContext) + 'static,
940 ) -> Subscription {
941 let (subscription, activate) = self.keystroke_observers.insert((), Box::new(f));
942 activate();
943 subscription
944 }
945
946 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
947 self.text_style_stack.push(text_style);
948 }
949
950 pub(crate) fn pop_text_style(&mut self) {
951 self.text_style_stack.pop();
952 }
953
954 /// Register key bindings.
955 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
956 self.keymap.lock().add_bindings(bindings);
957 self.pending_effects.push_back(Effect::Refresh);
958 }
959
960 pub fn clear_key_bindings(&mut self) {
961 self.keymap.lock().clear();
962 self.pending_effects.push_back(Effect::Refresh);
963 }
964
965 /// Register a global listener for actions invoked via the keyboard.
966 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
967 self.global_action_listeners
968 .entry(TypeId::of::<A>())
969 .or_default()
970 .push(Rc::new(move |action, phase, cx| {
971 if phase == DispatchPhase::Bubble {
972 let action = action.downcast_ref().unwrap();
973 listener(action, cx)
974 }
975 }));
976 }
977
978 /// Event handlers propagate events by default. Call this method to stop dispatching to
979 /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
980 /// the opposite of [`Self::propagate`]. It's also possible to cancel a call to [`Self::propagate`] by
981 /// calling this method before effects are flushed.
982 pub fn stop_propagation(&mut self) {
983 self.propagate_event = false;
984 }
985
986 /// Action handlers stop propagation by default during the bubble phase of action dispatch
987 /// dispatching to action handlers higher in the element tree. This is the opposite of
988 /// [`Self::stop_propagation`]. It's also possible to cancel a call to [`Self::stop_propagation`] by calling
989 /// this method before effects are flushed.
990 pub fn propagate(&mut self) {
991 self.propagate_event = true;
992 }
993
994 pub fn build_action(
995 &self,
996 name: &str,
997 data: Option<serde_json::Value>,
998 ) -> Result<Box<dyn Action>> {
999 self.actions.build_action(name, data)
1000 }
1001
1002 pub fn all_action_names(&self) -> &[SharedString] {
1003 self.actions.all_action_names()
1004 }
1005
1006 pub fn on_app_quit<Fut>(
1007 &mut self,
1008 mut on_quit: impl FnMut(&mut AppContext) -> Fut + 'static,
1009 ) -> Subscription
1010 where
1011 Fut: 'static + Future<Output = ()>,
1012 {
1013 let (subscription, activate) = self.quit_observers.insert(
1014 (),
1015 Box::new(move |cx| {
1016 let future = on_quit(cx);
1017 future.boxed_local()
1018 }),
1019 );
1020 activate();
1021 subscription
1022 }
1023
1024 pub(crate) fn clear_pending_keystrokes(&mut self) {
1025 for window in self.windows() {
1026 window
1027 .update(self, |_, cx| {
1028 cx.window
1029 .rendered_frame
1030 .dispatch_tree
1031 .clear_pending_keystrokes();
1032 cx.window
1033 .next_frame
1034 .dispatch_tree
1035 .clear_pending_keystrokes();
1036 })
1037 .ok();
1038 }
1039 }
1040
1041 pub fn is_action_available(&mut self, action: &dyn Action) -> bool {
1042 if let Some(window) = self.active_window() {
1043 if let Ok(window_action_available) =
1044 window.update(self, |_, cx| cx.is_action_available(action))
1045 {
1046 return window_action_available;
1047 }
1048 }
1049
1050 self.global_action_listeners
1051 .contains_key(&action.as_any().type_id())
1052 }
1053
1054 pub fn set_menus(&mut self, menus: Vec<Menu>) {
1055 self.platform.set_menus(menus, &self.keymap.lock());
1056 }
1057
1058 pub fn dispatch_action(&mut self, action: &dyn Action) {
1059 if let Some(active_window) = self.active_window() {
1060 active_window
1061 .update(self, |_, cx| cx.dispatch_action(action.boxed_clone()))
1062 .log_err();
1063 } else {
1064 self.propagate_event = true;
1065
1066 if let Some(mut global_listeners) = self
1067 .global_action_listeners
1068 .remove(&action.as_any().type_id())
1069 {
1070 for listener in &global_listeners {
1071 listener(action.as_any(), DispatchPhase::Capture, self);
1072 if !self.propagate_event {
1073 break;
1074 }
1075 }
1076
1077 global_listeners.extend(
1078 self.global_action_listeners
1079 .remove(&action.as_any().type_id())
1080 .unwrap_or_default(),
1081 );
1082
1083 self.global_action_listeners
1084 .insert(action.as_any().type_id(), global_listeners);
1085 }
1086
1087 if self.propagate_event {
1088 if let Some(mut global_listeners) = self
1089 .global_action_listeners
1090 .remove(&action.as_any().type_id())
1091 {
1092 for listener in global_listeners.iter().rev() {
1093 listener(action.as_any(), DispatchPhase::Bubble, self);
1094 if !self.propagate_event {
1095 break;
1096 }
1097 }
1098
1099 global_listeners.extend(
1100 self.global_action_listeners
1101 .remove(&action.as_any().type_id())
1102 .unwrap_or_default(),
1103 );
1104
1105 self.global_action_listeners
1106 .insert(action.as_any().type_id(), global_listeners);
1107 }
1108 }
1109 }
1110 }
1111
1112 pub fn has_active_drag(&self) -> bool {
1113 self.active_drag.is_some()
1114 }
1115}
1116
1117impl Context for AppContext {
1118 type Result<T> = T;
1119
1120 /// Build an entity that is owned by the application. The given function will be invoked with
1121 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
1122 /// which can be used to access the entity in a context.
1123 fn new_model<T: 'static>(
1124 &mut self,
1125 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1126 ) -> Model<T> {
1127 self.update(|cx| {
1128 let slot = cx.entities.reserve();
1129 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
1130 cx.entities.insert(slot, entity)
1131 })
1132 }
1133
1134 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
1135 /// entity along with a `ModelContext` for the entity.
1136 fn update_model<T: 'static, R>(
1137 &mut self,
1138 model: &Model<T>,
1139 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1140 ) -> R {
1141 self.update(|cx| {
1142 let mut entity = cx.entities.lease(model);
1143 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
1144 cx.entities.end_lease(entity);
1145 result
1146 })
1147 }
1148
1149 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
1150 where
1151 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1152 {
1153 self.update(|cx| {
1154 let mut window = cx
1155 .windows
1156 .get_mut(handle.id)
1157 .ok_or_else(|| anyhow!("window not found"))?
1158 .take()
1159 .unwrap();
1160
1161 let root_view = window.root_view.clone().unwrap();
1162 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
1163
1164 if window.removed {
1165 cx.windows.remove(handle.id);
1166 } else {
1167 cx.windows
1168 .get_mut(handle.id)
1169 .ok_or_else(|| anyhow!("window not found"))?
1170 .replace(window);
1171 }
1172
1173 Ok(result)
1174 })
1175 }
1176
1177 fn read_model<T, R>(
1178 &self,
1179 handle: &Model<T>,
1180 read: impl FnOnce(&T, &AppContext) -> R,
1181 ) -> Self::Result<R>
1182 where
1183 T: 'static,
1184 {
1185 let entity = self.entities.read(handle);
1186 read(entity, self)
1187 }
1188
1189 fn read_window<T, R>(
1190 &self,
1191 window: &WindowHandle<T>,
1192 read: impl FnOnce(View<T>, &AppContext) -> R,
1193 ) -> Result<R>
1194 where
1195 T: 'static,
1196 {
1197 let window = self
1198 .windows
1199 .get(window.id)
1200 .ok_or_else(|| anyhow!("window not found"))?
1201 .as_ref()
1202 .unwrap();
1203
1204 let root_view = window.root_view.clone().unwrap();
1205 let view = root_view
1206 .downcast::<T>()
1207 .map_err(|_| anyhow!("root view's type has changed"))?;
1208
1209 Ok(read(view, self))
1210 }
1211}
1212
1213/// These effects are processed at the end of each application update cycle.
1214pub(crate) enum Effect {
1215 Notify {
1216 emitter: EntityId,
1217 },
1218 Emit {
1219 emitter: EntityId,
1220 event_type: TypeId,
1221 event: Box<dyn Any>,
1222 },
1223 Refresh,
1224 NotifyGlobalObservers {
1225 global_type: TypeId,
1226 },
1227 Defer {
1228 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
1229 },
1230}
1231
1232/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
1233pub(crate) struct GlobalLease<G: 'static> {
1234 global: Box<dyn Any>,
1235 global_type: PhantomData<G>,
1236}
1237
1238impl<G: 'static> GlobalLease<G> {
1239 fn new(global: Box<dyn Any>) -> Self {
1240 GlobalLease {
1241 global,
1242 global_type: PhantomData,
1243 }
1244 }
1245}
1246
1247impl<G: 'static> Deref for GlobalLease<G> {
1248 type Target = G;
1249
1250 fn deref(&self) -> &Self::Target {
1251 self.global.downcast_ref().unwrap()
1252 }
1253}
1254
1255impl<G: 'static> DerefMut for GlobalLease<G> {
1256 fn deref_mut(&mut self) -> &mut Self::Target {
1257 self.global.downcast_mut().unwrap()
1258 }
1259}
1260
1261/// Contains state associated with an active drag operation, started by dragging an element
1262/// within the window or by dragging into the app from the underlying platform.
1263pub struct AnyDrag {
1264 pub view: AnyView,
1265 pub value: Box<dyn Any>,
1266 pub cursor_offset: Point<Pixels>,
1267}
1268
1269/// Contains state associated with a tooltip. You'll only need this struct if you're implementing
1270/// tooltip behavior on a custom element. Otherwise, use [Div::tooltip].
1271#[derive(Clone)]
1272pub struct AnyTooltip {
1273 pub view: AnyView,
1274 pub cursor_offset: Point<Pixels>,
1275}
1276
1277#[derive(Debug)]
1278pub struct KeystrokeEvent {
1279 pub keystroke: Keystroke,
1280 pub action: Option<Box<dyn Action>>,
1281}