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