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 smallvec::SmallVec;
13use smol::future::FutureExt;
14#[cfg(any(test, feature = "test-support"))]
15pub use test_context::*;
16
17use crate::{
18 current_platform, image_cache::ImageCache, Action, ActionRegistry, Any, AnyView,
19 AnyWindowHandle, AppMetadata, AssetSource, BackgroundExecutor, ClipboardItem, Context,
20 DispatchPhase, DisplayId, Entity, EventEmitter, FocusEvent, FocusHandle, FocusId,
21 ForegroundExecutor, KeyBinding, Keymap, LayoutId, PathPromptOptions, Pixels, Platform,
22 PlatformDisplay, Point, Render, SharedString, SubscriberSet, Subscription, SvgRenderer, Task,
23 TextStyle, TextStyleRefinement, TextSystem, View, ViewContext, Window, WindowContext,
24 WindowHandle, WindowId,
25};
26use anyhow::{anyhow, Result};
27use collections::{HashMap, HashSet, VecDeque};
28use futures::{channel::oneshot, future::LocalBoxFuture, Future};
29use parking_lot::Mutex;
30use slotmap::SlotMap;
31use std::{
32 any::{type_name, TypeId},
33 cell::{Ref, RefCell, RefMut},
34 marker::PhantomData,
35 mem,
36 ops::{Deref, DerefMut},
37 path::{Path, PathBuf},
38 rc::{Rc, Weak},
39 sync::{atomic::Ordering::SeqCst, Arc},
40 time::Duration,
41};
42use util::{
43 http::{self, HttpClient},
44 ResultExt,
45};
46
47/// Temporary(?) wrapper around RefCell<AppContext> to help us debug any double borrows.
48/// Strongly consider removing after stabilization.
49pub struct AppCell {
50 app: RefCell<AppContext>,
51}
52
53impl AppCell {
54 #[track_caller]
55 pub fn borrow(&self) -> AppRef {
56 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
57 let thread_id = std::thread::current().id();
58 eprintln!("borrowed {thread_id:?}");
59 }
60 AppRef(self.app.borrow())
61 }
62
63 #[track_caller]
64 pub fn borrow_mut(&self) -> AppRefMut {
65 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
66 let thread_id = std::thread::current().id();
67 eprintln!("borrowed {thread_id:?}");
68 }
69 AppRefMut(self.app.borrow_mut())
70 }
71}
72
73#[derive(Deref, DerefMut)]
74pub struct AppRef<'a>(Ref<'a, AppContext>);
75
76impl<'a> Drop for AppRef<'a> {
77 fn drop(&mut self) {
78 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
79 let thread_id = std::thread::current().id();
80 eprintln!("dropped borrow from {thread_id:?}");
81 }
82 }
83}
84
85#[derive(Deref, DerefMut)]
86pub struct AppRefMut<'a>(RefMut<'a, AppContext>);
87
88impl<'a> Drop for AppRefMut<'a> {
89 fn drop(&mut self) {
90 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
91 let thread_id = std::thread::current().id();
92 eprintln!("dropped {thread_id:?}");
93 }
94 }
95}
96
97pub struct App(Rc<AppCell>);
98
99/// Represents an application before it is fully launched. Once your app is
100/// configured, you'll start the app with `App::run`.
101impl App {
102 /// Builds an app with the given asset source.
103 pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
104 Self(AppContext::new(
105 current_platform(),
106 asset_source,
107 http::client(),
108 ))
109 }
110
111 /// Start the application. The provided callback will be called once the
112 /// app is fully launched.
113 pub fn run<F>(self, on_finish_launching: F)
114 where
115 F: 'static + FnOnce(&mut AppContext),
116 {
117 let this = self.0.clone();
118 let platform = self.0.borrow().platform.clone();
119 platform.run(Box::new(move || {
120 let cx = &mut *this.borrow_mut();
121 on_finish_launching(cx);
122 }));
123 }
124
125 /// Register a handler to be invoked when the platform instructs the application
126 /// to open one or more URLs.
127 pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
128 where
129 F: 'static + FnMut(Vec<String>, &mut AppContext),
130 {
131 let this = Rc::downgrade(&self.0);
132 self.0.borrow().platform.on_open_urls(Box::new(move |urls| {
133 if let Some(app) = this.upgrade() {
134 callback(urls, &mut *app.borrow_mut());
135 }
136 }));
137 self
138 }
139
140 pub fn on_reopen<F>(&self, mut callback: F) -> &Self
141 where
142 F: 'static + FnMut(&mut AppContext),
143 {
144 let this = Rc::downgrade(&self.0);
145 self.0.borrow_mut().platform.on_reopen(Box::new(move || {
146 if let Some(app) = this.upgrade() {
147 callback(&mut app.borrow_mut());
148 }
149 }));
150 self
151 }
152
153 pub fn metadata(&self) -> AppMetadata {
154 self.0.borrow().app_metadata.clone()
155 }
156
157 pub fn background_executor(&self) -> BackgroundExecutor {
158 self.0.borrow().background_executor.clone()
159 }
160
161 pub fn foreground_executor(&self) -> ForegroundExecutor {
162 self.0.borrow().foreground_executor.clone()
163 }
164
165 pub fn text_system(&self) -> Arc<TextSystem> {
166 self.0.borrow().text_system.clone()
167 }
168}
169
170pub(crate) type FrameCallback = Box<dyn FnOnce(&mut AppContext)>;
171type Handler = Box<dyn FnMut(&mut AppContext) -> bool + 'static>;
172type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + '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: HashMap<DisplayId, Vec<FrameCallback>>,
194 pub(crate) frame_consumers: HashMap<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: HashMap<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 HashMap<TypeId, Vec<Box<dyn Fn(&dyn Action, DispatchPhase, &mut Self)>>>,
208 pending_effects: VecDeque<Effect>,
209 pub(crate) pending_notifications: HashSet<EntityId>,
210 pub(crate) pending_global_notifications: HashSet<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) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
215 pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
216 pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
217 pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
218 pub(crate) propagate_event: bool,
219}
220
221impl AppContext {
222 pub(crate) fn new(
223 platform: Rc<dyn Platform>,
224 asset_source: Arc<dyn AssetSource>,
225 http_client: Arc<dyn HttpClient>,
226 ) -> Rc<AppCell> {
227 let executor = platform.background_executor();
228 let foreground_executor = platform.foreground_executor();
229 assert!(
230 executor.is_main_thread(),
231 "must construct App on main thread"
232 );
233
234 let text_system = Arc::new(TextSystem::new(platform.text_system()));
235 let entities = EntityMap::new();
236
237 let app_metadata = AppMetadata {
238 os_name: platform.os_name(),
239 os_version: platform.os_version().ok(),
240 app_version: platform.app_version().ok(),
241 };
242
243 let app = Rc::new_cyclic(|this| AppCell {
244 app: RefCell::new(AppContext {
245 this: this.clone(),
246 platform: platform.clone(),
247 app_metadata,
248 text_system,
249 actions: Rc::new(ActionRegistry::default()),
250 flushing_effects: false,
251 pending_updates: 0,
252 active_drag: None,
253 active_tooltip: None,
254 next_frame_callbacks: HashMap::default(),
255 frame_consumers: HashMap::default(),
256 background_executor: executor,
257 foreground_executor,
258 svg_renderer: SvgRenderer::new(asset_source.clone()),
259 asset_source,
260 image_cache: ImageCache::new(http_client),
261 text_style_stack: Vec::new(),
262 globals_by_type: HashMap::default(),
263 entities,
264 new_view_observers: SubscriberSet::new(),
265 windows: SlotMap::with_key(),
266 keymap: Arc::new(Mutex::new(Keymap::default())),
267 global_action_listeners: HashMap::default(),
268 pending_effects: VecDeque::new(),
269 pending_notifications: HashSet::default(),
270 pending_global_notifications: HashSet::default(),
271 observers: SubscriberSet::new(),
272 event_listeners: SubscriberSet::new(),
273 release_listeners: SubscriberSet::new(),
274 global_observers: SubscriberSet::new(),
275 quit_observers: SubscriberSet::new(),
276 layout_id_buffer: Default::default(),
277 propagate_event: true,
278 }),
279 });
280
281 platform.on_quit(Box::new({
282 let cx = app.clone();
283 move || {
284 cx.borrow_mut().shutdown();
285 }
286 }));
287
288 app
289 }
290
291 /// Quit the application gracefully. Handlers registered with `ModelContext::on_app_quit`
292 /// will be given 100ms to complete before exiting.
293 pub fn shutdown(&mut self) {
294 let mut futures = Vec::new();
295
296 for observer in self.quit_observers.remove(&()) {
297 futures.push(observer(self));
298 }
299
300 self.windows.clear();
301 self.flush_effects();
302
303 let futures = futures::future::join_all(futures);
304 if self
305 .background_executor
306 .block_with_timeout(Duration::from_millis(100), futures)
307 .is_err()
308 {
309 log::error!("timed out waiting on app_will_quit");
310 }
311 }
312
313 pub fn quit(&mut self) {
314 self.platform.quit();
315 }
316
317 pub fn app_metadata(&self) -> AppMetadata {
318 self.app_metadata.clone()
319 }
320
321 /// Schedules all windows in the application to be redrawn. This can be called
322 /// multiple times in an update cycle and still result in a single redraw.
323 pub fn refresh(&mut self) {
324 self.pending_effects.push_back(Effect::Refresh);
325 }
326 pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
327 self.pending_updates += 1;
328 let result = update(self);
329 if !self.flushing_effects && self.pending_updates == 1 {
330 self.flushing_effects = true;
331 self.flush_effects();
332 self.flushing_effects = false;
333 }
334 self.pending_updates -= 1;
335 result
336 }
337
338 pub fn observe<W, E>(
339 &mut self,
340 entity: &E,
341 mut on_notify: impl FnMut(E, &mut AppContext) + 'static,
342 ) -> Subscription
343 where
344 W: 'static,
345 E: Entity<W>,
346 {
347 self.observe_internal(entity, move |e, cx| {
348 on_notify(e, cx);
349 true
350 })
351 }
352
353 pub fn observe_internal<W, E>(
354 &mut self,
355 entity: &E,
356 mut on_notify: impl FnMut(E, &mut AppContext) -> bool + 'static,
357 ) -> Subscription
358 where
359 W: 'static,
360 E: Entity<W>,
361 {
362 let entity_id = entity.entity_id();
363 let handle = entity.downgrade();
364 let (subscription, activate) = self.observers.insert(
365 entity_id,
366 Box::new(move |cx| {
367 if let Some(handle) = E::upgrade_from(&handle) {
368 on_notify(handle, cx)
369 } else {
370 false
371 }
372 }),
373 );
374 self.defer(move |_| activate());
375 subscription
376 }
377
378 pub fn subscribe<T, E, Evt>(
379 &mut self,
380 entity: &E,
381 mut on_event: impl FnMut(E, &Evt, &mut AppContext) + 'static,
382 ) -> Subscription
383 where
384 T: 'static + EventEmitter<Evt>,
385 E: Entity<T>,
386 Evt: 'static,
387 {
388 self.subscribe_internal(entity, move |entity, event, cx| {
389 on_event(entity, event, cx);
390 true
391 })
392 }
393
394 pub(crate) fn subscribe_internal<T, E, Evt>(
395 &mut self,
396 entity: &E,
397 mut on_event: impl FnMut(E, &Evt, &mut AppContext) -> bool + 'static,
398 ) -> Subscription
399 where
400 T: 'static + EventEmitter<Evt>,
401 E: Entity<T>,
402 Evt: 'static,
403 {
404 let entity_id = entity.entity_id();
405 let entity = entity.downgrade();
406 let (subscription, activate) = self.event_listeners.insert(
407 entity_id,
408 (
409 TypeId::of::<Evt>(),
410 Box::new(move |event, cx| {
411 let event: &Evt = event.downcast_ref().expect("invalid event type");
412 if let Some(handle) = E::upgrade_from(&entity) {
413 on_event(handle, event, cx)
414 } else {
415 false
416 }
417 }),
418 ),
419 );
420 self.defer(move |_| activate());
421 subscription
422 }
423
424 pub fn windows(&self) -> Vec<AnyWindowHandle> {
425 self.windows
426 .values()
427 .filter_map(|window| Some(window.as_ref()?.handle.clone()))
428 .collect()
429 }
430
431 pub fn active_window(&self) -> Option<AnyWindowHandle> {
432 self.platform.active_window()
433 }
434
435 /// Opens a new window with the given option and the root view returned by the given function.
436 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
437 /// functionality.
438 pub fn open_window<V: 'static + Render>(
439 &mut self,
440 options: crate::WindowOptions,
441 build_root_view: impl FnOnce(&mut WindowContext) -> View<V>,
442 ) -> WindowHandle<V> {
443 self.update(|cx| {
444 let id = cx.windows.insert(None);
445 let handle = WindowHandle::new(id);
446 let mut window = Window::new(handle.into(), options, cx);
447 let root_view = build_root_view(&mut WindowContext::new(cx, &mut window));
448 window.root_view.replace(root_view.into());
449 cx.windows.get_mut(id).unwrap().replace(window);
450 handle
451 })
452 }
453
454 /// Instructs the platform to activate the application by bringing it to the foreground.
455 pub fn activate(&self, ignoring_other_apps: bool) {
456 self.platform.activate(ignoring_other_apps);
457 }
458
459 pub fn hide(&self) {
460 self.platform.hide();
461 }
462
463 pub fn hide_other_apps(&self) {
464 self.platform.hide_other_apps();
465 }
466
467 pub fn unhide_other_apps(&self) {
468 self.platform.unhide_other_apps();
469 }
470
471 /// Returns the list of currently active displays.
472 pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
473 self.platform.displays()
474 }
475
476 /// Writes data to the platform clipboard.
477 pub fn write_to_clipboard(&self, item: ClipboardItem) {
478 self.platform.write_to_clipboard(item)
479 }
480
481 /// Reads data from the platform clipboard.
482 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
483 self.platform.read_from_clipboard()
484 }
485
486 /// Writes credentials to the platform keychain.
487 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
488 self.platform.write_credentials(url, username, password)
489 }
490
491 /// Reads credentials from the platform keychain.
492 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
493 self.platform.read_credentials(url)
494 }
495
496 /// Deletes credentials from the platform keychain.
497 pub fn delete_credentials(&self, url: &str) -> Result<()> {
498 self.platform.delete_credentials(url)
499 }
500
501 /// Directs the platform's default browser to open the given URL.
502 pub fn open_url(&self, url: &str) {
503 self.platform.open_url(url);
504 }
505
506 pub fn app_path(&self) -> Result<PathBuf> {
507 self.platform.app_path()
508 }
509
510 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
511 self.platform.path_for_auxiliary_executable(name)
512 }
513
514 pub fn prompt_for_paths(
515 &self,
516 options: PathPromptOptions,
517 ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
518 self.platform.prompt_for_paths(options)
519 }
520
521 pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
522 self.platform.prompt_for_new_path(directory)
523 }
524
525 pub fn reveal_path(&self, path: &Path) {
526 self.platform.reveal_path(path)
527 }
528
529 pub fn should_auto_hide_scrollbars(&self) -> bool {
530 self.platform.should_auto_hide_scrollbars()
531 }
532
533 pub fn restart(&self) {
534 self.platform.restart()
535 }
536
537 pub(crate) fn push_effect(&mut self, effect: Effect) {
538 match &effect {
539 Effect::Notify { emitter } => {
540 if !self.pending_notifications.insert(*emitter) {
541 return;
542 }
543 }
544 Effect::NotifyGlobalObservers { global_type } => {
545 if !self.pending_global_notifications.insert(*global_type) {
546 return;
547 }
548 }
549 _ => {}
550 };
551
552 self.pending_effects.push_back(effect);
553 }
554
555 /// Called at the end of AppContext::update to complete any side effects
556 /// such as notifying observers, emitting events, etc. Effects can themselves
557 /// cause effects, so we continue looping until all effects are processed.
558 fn flush_effects(&mut self) {
559 loop {
560 self.release_dropped_entities();
561 self.release_dropped_focus_handles();
562 if let Some(effect) = self.pending_effects.pop_front() {
563 match effect {
564 Effect::Notify { emitter } => {
565 self.apply_notify_effect(emitter);
566 }
567 Effect::Emit {
568 emitter,
569 event_type,
570 event,
571 } => self.apply_emit_effect(emitter, event_type, event),
572 Effect::FocusChanged {
573 window_handle,
574 focused,
575 } => {
576 self.apply_focus_changed_effect(window_handle, focused);
577 }
578 Effect::Refresh => {
579 self.apply_refresh_effect();
580 }
581 Effect::NotifyGlobalObservers { global_type } => {
582 self.apply_notify_global_observers_effect(global_type);
583 }
584 Effect::Defer { callback } => {
585 self.apply_defer_effect(callback);
586 }
587 }
588 } else {
589 break;
590 }
591 }
592
593 let dirty_window_ids = self
594 .windows
595 .iter()
596 .filter_map(|(_, window)| {
597 let window = window.as_ref()?;
598 if window.dirty {
599 Some(window.handle.clone())
600 } else {
601 None
602 }
603 })
604 .collect::<SmallVec<[_; 8]>>();
605
606 for dirty_window_handle in dirty_window_ids {
607 dirty_window_handle.update(self, |_, cx| cx.draw()).unwrap();
608 }
609 }
610
611 /// Repeatedly called during `flush_effects` to release any entities whose
612 /// reference count has become zero. We invoke any release observers before dropping
613 /// each entity.
614 fn release_dropped_entities(&mut self) {
615 loop {
616 let dropped = self.entities.take_dropped();
617 if dropped.is_empty() {
618 break;
619 }
620
621 for (entity_id, mut entity) in dropped {
622 self.observers.remove(&entity_id);
623 self.event_listeners.remove(&entity_id);
624 for release_callback in self.release_listeners.remove(&entity_id) {
625 release_callback(entity.as_mut(), self);
626 }
627 }
628 }
629 }
630
631 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
632 /// For now, we simply blur the window if this happens, but we may want to support invoking
633 /// a window blur handler to restore focus to some logical element.
634 fn release_dropped_focus_handles(&mut self) {
635 for window_handle in self.windows() {
636 window_handle
637 .update(self, |_, cx| {
638 let mut blur_window = false;
639 let focus = cx.window.focus;
640 cx.window.focus_handles.write().retain(|handle_id, count| {
641 if count.load(SeqCst) == 0 {
642 if focus == Some(handle_id) {
643 blur_window = true;
644 }
645 false
646 } else {
647 true
648 }
649 });
650
651 if blur_window {
652 cx.blur();
653 }
654 })
655 .unwrap();
656 }
657 }
658
659 fn apply_notify_effect(&mut self, emitter: EntityId) {
660 self.pending_notifications.remove(&emitter);
661
662 self.observers
663 .clone()
664 .retain(&emitter, |handler| handler(self));
665 }
666
667 fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: Box<dyn Any>) {
668 self.event_listeners
669 .clone()
670 .retain(&emitter, |(stored_type, handler)| {
671 if *stored_type == event_type {
672 handler(event.as_ref(), self)
673 } else {
674 true
675 }
676 });
677 }
678
679 fn apply_focus_changed_effect(
680 &mut self,
681 window_handle: AnyWindowHandle,
682 focused: Option<FocusId>,
683 ) {
684 window_handle
685 .update(self, |_, cx| {
686 // The window might change focus multiple times in an effect cycle.
687 // We only honor effects for the most recently focused handle.
688 if cx.window.focus == focused {
689 // if someone calls focus multiple times in one frame with the same handle
690 // the first apply_focus_changed_effect will have taken the last blur already
691 // and run the rest of this, so we can return.
692 let Some(last_blur) = cx.window.last_blur.take() else {
693 return;
694 };
695
696 let focused = focused
697 .map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
698
699 let blurred =
700 last_blur.and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
701
702 let focus_changed = focused.is_some() || blurred.is_some();
703 let event = FocusEvent { focused, blurred };
704
705 let mut listeners = mem::take(&mut cx.window.current_frame.focus_listeners);
706 if focus_changed {
707 for listener in &mut listeners {
708 listener(&event, cx);
709 }
710 }
711 listeners.extend(cx.window.current_frame.focus_listeners.drain(..));
712 cx.window.current_frame.focus_listeners = listeners;
713
714 if focus_changed {
715 cx.window
716 .focus_listeners
717 .clone()
718 .retain(&(), |listener| listener(&event, cx));
719 }
720 }
721 })
722 .ok();
723 }
724
725 fn apply_refresh_effect(&mut self) {
726 for window in self.windows.values_mut() {
727 if let Some(window) = window.as_mut() {
728 window.dirty = true;
729 }
730 }
731 }
732
733 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
734 self.pending_global_notifications.remove(&type_id);
735 self.global_observers
736 .clone()
737 .retain(&type_id, |observer| observer(self));
738 }
739
740 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
741 callback(self);
742 }
743
744 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
745 /// so it can be held across `await` points.
746 pub fn to_async(&self) -> AsyncAppContext {
747 AsyncAppContext {
748 app: unsafe { mem::transmute(self.this.clone()) },
749 background_executor: self.background_executor.clone(),
750 foreground_executor: self.foreground_executor.clone(),
751 }
752 }
753
754 /// Obtains a reference to the executor, which can be used to spawn futures.
755 pub fn background_executor(&self) -> &BackgroundExecutor {
756 &self.background_executor
757 }
758
759 /// Obtains a reference to the executor, which can be used to spawn futures.
760 pub fn foreground_executor(&self) -> &ForegroundExecutor {
761 &self.foreground_executor
762 }
763
764 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
765 /// with AsyncAppContext, which allows the application state to be accessed across await points.
766 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
767 where
768 Fut: Future<Output = R> + 'static,
769 R: 'static,
770 {
771 self.foreground_executor.spawn(f(self.to_async()))
772 }
773
774 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
775 /// that are currently on the stack to be returned to the app.
776 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
777 self.push_effect(Effect::Defer {
778 callback: Box::new(f),
779 });
780 }
781
782 /// Accessor for the application's asset source, which is provided when constructing the `App`.
783 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
784 &self.asset_source
785 }
786
787 /// Accessor for the text system.
788 pub fn text_system(&self) -> &Arc<TextSystem> {
789 &self.text_system
790 }
791
792 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
793 pub fn text_style(&self) -> TextStyle {
794 let mut style = TextStyle::default();
795 for refinement in &self.text_style_stack {
796 style.refine(refinement);
797 }
798 style
799 }
800
801 /// Check whether a global of the given type has been assigned.
802 pub fn has_global<G: 'static>(&self) -> bool {
803 self.globals_by_type.contains_key(&TypeId::of::<G>())
804 }
805
806 /// Access the global of the given type. Panics if a global for that type has not been assigned.
807 #[track_caller]
808 pub fn global<G: 'static>(&self) -> &G {
809 self.globals_by_type
810 .get(&TypeId::of::<G>())
811 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
812 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
813 .unwrap()
814 }
815
816 /// Access the global of the given type if a value has been assigned.
817 pub fn try_global<G: 'static>(&self) -> Option<&G> {
818 self.globals_by_type
819 .get(&TypeId::of::<G>())
820 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
821 }
822
823 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
824 #[track_caller]
825 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
826 let global_type = TypeId::of::<G>();
827 self.push_effect(Effect::NotifyGlobalObservers { global_type });
828 self.globals_by_type
829 .get_mut(&global_type)
830 .and_then(|any_state| any_state.downcast_mut::<G>())
831 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
832 .unwrap()
833 }
834
835 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
836 /// yet been assigned.
837 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
838 let global_type = TypeId::of::<G>();
839 self.push_effect(Effect::NotifyGlobalObservers { global_type });
840 self.globals_by_type
841 .entry(global_type)
842 .or_insert_with(|| Box::new(G::default()))
843 .downcast_mut::<G>()
844 .unwrap()
845 }
846
847 /// Set the value of the global of the given type.
848 pub fn set_global<G: Any>(&mut self, global: G) {
849 let global_type = TypeId::of::<G>();
850 self.push_effect(Effect::NotifyGlobalObservers { global_type });
851 self.globals_by_type.insert(global_type, Box::new(global));
852 }
853
854 /// Clear all stored globals. Does not notify global observers.
855 #[cfg(any(test, feature = "test-support"))]
856 pub fn clear_globals(&mut self) {
857 self.globals_by_type.drain();
858 }
859
860 /// Remove the global of the given type from the app context. Does not notify global observers.
861 #[cfg(any(test, feature = "test-support"))]
862 pub fn remove_global<G: Any>(&mut self) -> G {
863 let global_type = TypeId::of::<G>();
864 *self
865 .globals_by_type
866 .remove(&global_type)
867 .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
868 .downcast()
869 .unwrap()
870 }
871
872 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
873 /// your closure with mutable access to the `AppContext` and the global simultaneously.
874 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
875 let mut global = self.lease_global::<G>();
876 let result = f(&mut global, self);
877 self.end_global_lease(global);
878 result
879 }
880
881 /// Register a callback to be invoked when a global of the given type is updated.
882 pub fn observe_global<G: 'static>(
883 &mut self,
884 mut f: impl FnMut(&mut Self) + 'static,
885 ) -> Subscription {
886 let (subscription, activate) = self.global_observers.insert(
887 TypeId::of::<G>(),
888 Box::new(move |cx| {
889 f(cx);
890 true
891 }),
892 );
893 self.defer(move |_| activate());
894 subscription
895 }
896
897 /// Move the global of the given type to the stack.
898 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
899 GlobalLease::new(
900 self.globals_by_type
901 .remove(&TypeId::of::<G>())
902 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
903 .unwrap(),
904 )
905 }
906
907 /// Restore the global of the given type after it is moved to the stack.
908 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
909 let global_type = TypeId::of::<G>();
910 self.push_effect(Effect::NotifyGlobalObservers { global_type });
911 self.globals_by_type.insert(global_type, lease.global);
912 }
913
914 pub fn observe_new_views<V: 'static>(
915 &mut self,
916 on_new: impl 'static + Fn(&mut V, &mut ViewContext<V>),
917 ) -> Subscription {
918 let (subscription, activate) = self.new_view_observers.insert(
919 TypeId::of::<V>(),
920 Box::new(move |any_view: AnyView, cx: &mut WindowContext| {
921 any_view
922 .downcast::<V>()
923 .unwrap()
924 .update(cx, |view_state, cx| {
925 on_new(view_state, cx);
926 })
927 }),
928 );
929 activate();
930 subscription
931 }
932
933 pub fn observe_release<E, T>(
934 &mut self,
935 handle: &E,
936 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
937 ) -> Subscription
938 where
939 E: Entity<T>,
940 T: 'static,
941 {
942 let (subscription, activate) = self.release_listeners.insert(
943 handle.entity_id(),
944 Box::new(move |entity, cx| {
945 let entity = entity.downcast_mut().expect("invalid entity type");
946 on_release(entity, cx)
947 }),
948 );
949 activate();
950 subscription
951 }
952
953 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
954 self.text_style_stack.push(text_style);
955 }
956
957 pub(crate) fn pop_text_style(&mut self) {
958 self.text_style_stack.pop();
959 }
960
961 /// Register key bindings.
962 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
963 self.keymap.lock().add_bindings(bindings);
964 self.pending_effects.push_back(Effect::Refresh);
965 }
966
967 /// Register a global listener for actions invoked via the keyboard.
968 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
969 self.global_action_listeners
970 .entry(TypeId::of::<A>())
971 .or_default()
972 .push(Box::new(move |action, phase, cx| {
973 if phase == DispatchPhase::Bubble {
974 let action = action.as_any().downcast_ref().unwrap();
975 listener(action, cx)
976 }
977 }));
978 }
979
980 /// Event handlers propagate events by default. Call this method to stop dispatching to
981 /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
982 /// the opposite of [propagate]. It's also possible to cancel a call to [propagate] by
983 /// calling this method before effects are flushed.
984 pub fn stop_propagation(&mut self) {
985 self.propagate_event = false;
986 }
987
988 /// Action handlers stop propagation by default during the bubble phase of action dispatch
989 /// dispatching to action handlers higher in the element tree. This is the opposite of
990 /// [stop_propagation]. It's also possible to cancel a call to [stop_propagate] by calling
991 /// this method before effects are flushed.
992 pub fn propagate(&mut self) {
993 self.propagate_event = true;
994 }
995
996 pub fn build_action(
997 &self,
998 name: &str,
999 data: Option<serde_json::Value>,
1000 ) -> Result<Box<dyn Action>> {
1001 self.actions.build_action(name, data)
1002 }
1003
1004 pub fn all_action_names(&self) -> &[SharedString] {
1005 self.actions.all_action_names()
1006 }
1007
1008 pub fn on_app_quit<Fut>(
1009 &mut self,
1010 mut on_quit: impl FnMut(&mut AppContext) -> Fut + 'static,
1011 ) -> Subscription
1012 where
1013 Fut: 'static + Future<Output = ()>,
1014 {
1015 let (subscription, activate) = self.quit_observers.insert(
1016 (),
1017 Box::new(move |cx| {
1018 let future = on_quit(cx);
1019 async move { future.await }.boxed_local()
1020 }),
1021 );
1022 activate();
1023 subscription
1024 }
1025
1026 pub(crate) fn clear_pending_keystrokes(&mut self) {
1027 for window in self.windows() {
1028 window
1029 .update(self, |_, cx| {
1030 cx.window
1031 .current_frame
1032 .dispatch_tree
1033 .clear_pending_keystrokes()
1034 })
1035 .ok();
1036 }
1037 }
1038
1039 pub fn is_action_available(&mut self, action: &dyn Action) -> bool {
1040 if let Some(window) = self.active_window() {
1041 let window_action_available = window
1042 .update(self, |_, cx| {
1043 if let Some(focus_id) = cx.window.focus {
1044 cx.window
1045 .current_frame
1046 .dispatch_tree
1047 .is_action_available(action, focus_id)
1048 } else {
1049 false
1050 }
1051 })
1052 .unwrap_or(false);
1053 if window_action_available {
1054 return true;
1055 }
1056 }
1057
1058 self.global_action_listeners
1059 .contains_key(&action.as_any().type_id())
1060 }
1061
1062 pub fn dispatch_action(&mut self, action: &dyn Action) {
1063 self.propagate_event = true;
1064
1065 if let Some(mut global_listeners) = self
1066 .global_action_listeners
1067 .remove(&action.as_any().type_id())
1068 {
1069 for listener in &global_listeners {
1070 listener(action, DispatchPhase::Capture, self);
1071 if !self.propagate_event {
1072 break;
1073 }
1074 }
1075
1076 global_listeners.extend(
1077 self.global_action_listeners
1078 .remove(&action.as_any().type_id())
1079 .unwrap_or_default(),
1080 );
1081
1082 self.global_action_listeners
1083 .insert(action.as_any().type_id(), global_listeners);
1084 }
1085
1086 if self.propagate_event {
1087 if let Some(active_window) = self.active_window() {
1088 active_window
1089 .update(self, |_, cx| cx.dispatch_action(action.boxed_clone()))
1090 .log_err();
1091 }
1092 }
1093
1094 if self.propagate_event {
1095 if let Some(mut global_listeners) = self
1096 .global_action_listeners
1097 .remove(&action.as_any().type_id())
1098 {
1099 for listener in global_listeners.iter().rev() {
1100 listener(action, DispatchPhase::Bubble, self);
1101 if !self.propagate_event {
1102 break;
1103 }
1104 }
1105
1106 global_listeners.extend(
1107 self.global_action_listeners
1108 .remove(&action.as_any().type_id())
1109 .unwrap_or_default(),
1110 );
1111
1112 self.global_action_listeners
1113 .insert(action.as_any().type_id(), global_listeners);
1114 }
1115 }
1116 }
1117}
1118
1119impl Context for AppContext {
1120 type Result<T> = T;
1121
1122 /// Build an entity that is owned by the application. The given function will be invoked with
1123 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
1124 /// which can be used to access the entity in a context.
1125 fn build_model<T: 'static>(
1126 &mut self,
1127 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1128 ) -> Model<T> {
1129 self.update(|cx| {
1130 let slot = cx.entities.reserve();
1131 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
1132 cx.entities.insert(slot, entity)
1133 })
1134 }
1135
1136 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
1137 /// entity along with a `ModelContext` for the entity.
1138 fn update_model<T: 'static, R>(
1139 &mut self,
1140 model: &Model<T>,
1141 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1142 ) -> R {
1143 self.update(|cx| {
1144 let mut entity = cx.entities.lease(model);
1145 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
1146 cx.entities.end_lease(entity);
1147 result
1148 })
1149 }
1150
1151 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
1152 where
1153 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1154 {
1155 self.update(|cx| {
1156 let mut window = cx
1157 .windows
1158 .get_mut(handle.id)
1159 .ok_or_else(|| anyhow!("window not found"))?
1160 .take()
1161 .unwrap();
1162
1163 let root_view = window.root_view.clone().unwrap();
1164 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
1165
1166 if window.removed {
1167 cx.windows.remove(handle.id);
1168 } else {
1169 cx.windows
1170 .get_mut(handle.id)
1171 .ok_or_else(|| anyhow!("window not found"))?
1172 .replace(window);
1173 }
1174
1175 Ok(result)
1176 })
1177 }
1178
1179 fn read_model<T, R>(
1180 &self,
1181 handle: &Model<T>,
1182 read: impl FnOnce(&T, &AppContext) -> R,
1183 ) -> Self::Result<R>
1184 where
1185 T: 'static,
1186 {
1187 let entity = self.entities.read(handle);
1188 read(entity, self)
1189 }
1190
1191 fn read_window<T, R>(
1192 &self,
1193 window: &WindowHandle<T>,
1194 read: impl FnOnce(View<T>, &AppContext) -> R,
1195 ) -> Result<R>
1196 where
1197 T: 'static,
1198 {
1199 let window = self
1200 .windows
1201 .get(window.id)
1202 .ok_or_else(|| anyhow!("window not found"))?
1203 .as_ref()
1204 .unwrap();
1205
1206 let root_view = window.root_view.clone().unwrap();
1207 let view = root_view
1208 .downcast::<T>()
1209 .map_err(|_| anyhow!("root view's type has changed"))?;
1210
1211 Ok(read(view, self))
1212 }
1213}
1214
1215/// These effects are processed at the end of each application update cycle.
1216pub(crate) enum Effect {
1217 Notify {
1218 emitter: EntityId,
1219 },
1220 Emit {
1221 emitter: EntityId,
1222 event_type: TypeId,
1223 event: Box<dyn Any>,
1224 },
1225 FocusChanged {
1226 window_handle: AnyWindowHandle,
1227 focused: Option<FocusId>,
1228 },
1229 Refresh,
1230 NotifyGlobalObservers {
1231 global_type: TypeId,
1232 },
1233 Defer {
1234 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
1235 },
1236}
1237
1238/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
1239pub(crate) struct GlobalLease<G: 'static> {
1240 global: Box<dyn Any>,
1241 global_type: PhantomData<G>,
1242}
1243
1244impl<G: 'static> GlobalLease<G> {
1245 fn new(global: Box<dyn Any>) -> Self {
1246 GlobalLease {
1247 global,
1248 global_type: PhantomData,
1249 }
1250 }
1251}
1252
1253impl<G: 'static> Deref for GlobalLease<G> {
1254 type Target = G;
1255
1256 fn deref(&self) -> &Self::Target {
1257 self.global.downcast_ref().unwrap()
1258 }
1259}
1260
1261impl<G: 'static> DerefMut for GlobalLease<G> {
1262 fn deref_mut(&mut self) -> &mut Self::Target {
1263 self.global.downcast_mut().unwrap()
1264 }
1265}
1266
1267/// Contains state associated with an active drag operation, started by dragging an element
1268/// within the window or by dragging into the app from the underlying platform.
1269pub struct AnyDrag {
1270 pub view: AnyView,
1271 pub cursor_offset: Point<Pixels>,
1272}
1273
1274#[derive(Clone)]
1275pub(crate) struct AnyTooltip {
1276 pub view: AnyView,
1277 pub cursor_offset: Point<Pixels>,
1278}