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(crate) fn push_effect(&mut self, effect: Effect) {
524 match &effect {
525 Effect::Notify { emitter } => {
526 if !self.pending_notifications.insert(*emitter) {
527 return;
528 }
529 }
530 Effect::NotifyGlobalObservers { global_type } => {
531 if !self.pending_global_notifications.insert(*global_type) {
532 return;
533 }
534 }
535 _ => {}
536 };
537
538 self.pending_effects.push_back(effect);
539 }
540
541 /// Called at the end of AppContext::update to complete any side effects
542 /// such as notifying observers, emitting events, etc. Effects can themselves
543 /// cause effects, so we continue looping until all effects are processed.
544 fn flush_effects(&mut self) {
545 loop {
546 self.release_dropped_entities();
547 self.release_dropped_focus_handles();
548 if let Some(effect) = self.pending_effects.pop_front() {
549 match effect {
550 Effect::Notify { emitter } => {
551 self.apply_notify_effect(emitter);
552 }
553 Effect::Emit {
554 emitter,
555 event_type,
556 event,
557 } => self.apply_emit_effect(emitter, event_type, event),
558 Effect::FocusChanged {
559 window_handle,
560 focused,
561 } => {
562 self.apply_focus_changed_effect(window_handle, focused);
563 }
564 Effect::Refresh => {
565 self.apply_refresh_effect();
566 }
567 Effect::NotifyGlobalObservers { global_type } => {
568 self.apply_notify_global_observers_effect(global_type);
569 }
570 Effect::Defer { callback } => {
571 self.apply_defer_effect(callback);
572 }
573 }
574 } else {
575 break;
576 }
577 }
578
579 let dirty_window_ids = self
580 .windows
581 .iter()
582 .filter_map(|(_, window)| {
583 let window = window.as_ref().unwrap();
584 if window.dirty {
585 Some(window.handle.clone())
586 } else {
587 None
588 }
589 })
590 .collect::<SmallVec<[_; 8]>>();
591
592 for dirty_window_handle in dirty_window_ids {
593 dirty_window_handle.update(self, |_, cx| cx.draw()).unwrap();
594 }
595 }
596
597 /// Repeatedly called during `flush_effects` to release any entities whose
598 /// reference count has become zero. We invoke any release observers before dropping
599 /// each entity.
600 fn release_dropped_entities(&mut self) {
601 loop {
602 let dropped = self.entities.take_dropped();
603 if dropped.is_empty() {
604 break;
605 }
606
607 for (entity_id, mut entity) in dropped {
608 self.observers.remove(&entity_id);
609 self.event_listeners.remove(&entity_id);
610 for release_callback in self.release_listeners.remove(&entity_id) {
611 release_callback(entity.as_mut(), self);
612 }
613 }
614 }
615 }
616
617 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
618 /// For now, we simply blur the window if this happens, but we may want to support invoking
619 /// a window blur handler to restore focus to some logical element.
620 fn release_dropped_focus_handles(&mut self) {
621 for window_handle in self.windows() {
622 window_handle
623 .update(self, |_, cx| {
624 let mut blur_window = false;
625 let focus = cx.window.focus;
626 cx.window.focus_handles.write().retain(|handle_id, count| {
627 if count.load(SeqCst) == 0 {
628 if focus == Some(handle_id) {
629 blur_window = true;
630 }
631 false
632 } else {
633 true
634 }
635 });
636
637 if blur_window {
638 cx.blur();
639 }
640 })
641 .unwrap();
642 }
643 }
644
645 fn apply_notify_effect(&mut self, emitter: EntityId) {
646 self.pending_notifications.remove(&emitter);
647
648 self.observers
649 .clone()
650 .retain(&emitter, |handler| handler(self));
651 }
652
653 fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: Box<dyn Any>) {
654 self.event_listeners
655 .clone()
656 .retain(&emitter, |(stored_type, handler)| {
657 if *stored_type == event_type {
658 handler(event.as_ref(), self)
659 } else {
660 true
661 }
662 });
663 }
664
665 fn apply_focus_changed_effect(
666 &mut self,
667 window_handle: AnyWindowHandle,
668 focused: Option<FocusId>,
669 ) {
670 window_handle
671 .update(self, |_, cx| {
672 // The window might change focus multiple times in an effect cycle.
673 // We only honor effects for the most recently focused handle.
674 if cx.window.focus == focused {
675 // if someone calls focus multiple times in one frame with the same handle
676 // the first apply_focus_changed_effect will have taken the last blur already
677 // and run the rest of this, so we can return.
678 let Some(last_blur) = cx.window.last_blur.take() else {
679 return;
680 };
681
682 let focused = focused
683 .map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
684
685 let blurred =
686 last_blur.and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
687
688 let focus_changed = focused.is_some() || blurred.is_some();
689 let event = FocusEvent { focused, blurred };
690
691 let mut listeners = mem::take(&mut cx.window.current_frame.focus_listeners);
692 if focus_changed {
693 for listener in &mut listeners {
694 listener(&event, cx);
695 }
696 }
697 listeners.extend(cx.window.current_frame.focus_listeners.drain(..));
698 cx.window.current_frame.focus_listeners = listeners;
699
700 if focus_changed {
701 cx.window
702 .focus_listeners
703 .clone()
704 .retain(&(), |listener| listener(&event, cx));
705 }
706 }
707 })
708 .ok();
709 }
710
711 fn apply_refresh_effect(&mut self) {
712 for window in self.windows.values_mut() {
713 if let Some(window) = window.as_mut() {
714 window.dirty = true;
715 }
716 }
717 }
718
719 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
720 self.pending_global_notifications.remove(&type_id);
721 self.global_observers
722 .clone()
723 .retain(&type_id, |observer| observer(self));
724 }
725
726 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
727 callback(self);
728 }
729
730 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
731 /// so it can be held across `await` points.
732 pub fn to_async(&self) -> AsyncAppContext {
733 AsyncAppContext {
734 app: unsafe { mem::transmute(self.this.clone()) },
735 background_executor: self.background_executor.clone(),
736 foreground_executor: self.foreground_executor.clone(),
737 }
738 }
739
740 /// Obtains a reference to the executor, which can be used to spawn futures.
741 pub fn background_executor(&self) -> &BackgroundExecutor {
742 &self.background_executor
743 }
744
745 /// Obtains a reference to the executor, which can be used to spawn futures.
746 pub fn foreground_executor(&self) -> &ForegroundExecutor {
747 &self.foreground_executor
748 }
749
750 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
751 /// with AsyncAppContext, which allows the application state to be accessed across await points.
752 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
753 where
754 Fut: Future<Output = R> + 'static,
755 R: 'static,
756 {
757 self.foreground_executor.spawn(f(self.to_async()))
758 }
759
760 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
761 /// that are currently on the stack to be returned to the app.
762 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
763 self.push_effect(Effect::Defer {
764 callback: Box::new(f),
765 });
766 }
767
768 /// Accessor for the application's asset source, which is provided when constructing the `App`.
769 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
770 &self.asset_source
771 }
772
773 /// Accessor for the text system.
774 pub fn text_system(&self) -> &Arc<TextSystem> {
775 &self.text_system
776 }
777
778 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
779 pub fn text_style(&self) -> TextStyle {
780 let mut style = TextStyle::default();
781 for refinement in &self.text_style_stack {
782 style.refine(refinement);
783 }
784 style
785 }
786
787 /// Check whether a global of the given type has been assigned.
788 pub fn has_global<G: 'static>(&self) -> bool {
789 self.globals_by_type.contains_key(&TypeId::of::<G>())
790 }
791
792 /// Access the global of the given type. Panics if a global for that type has not been assigned.
793 #[track_caller]
794 pub fn global<G: 'static>(&self) -> &G {
795 self.globals_by_type
796 .get(&TypeId::of::<G>())
797 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
798 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
799 .unwrap()
800 }
801
802 /// Access the global of the given type if a value has been assigned.
803 pub fn try_global<G: 'static>(&self) -> Option<&G> {
804 self.globals_by_type
805 .get(&TypeId::of::<G>())
806 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
807 }
808
809 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
810 #[track_caller]
811 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
812 let global_type = TypeId::of::<G>();
813 self.push_effect(Effect::NotifyGlobalObservers { global_type });
814 self.globals_by_type
815 .get_mut(&global_type)
816 .and_then(|any_state| any_state.downcast_mut::<G>())
817 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
818 .unwrap()
819 }
820
821 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
822 /// yet been assigned.
823 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
824 let global_type = TypeId::of::<G>();
825 self.push_effect(Effect::NotifyGlobalObservers { global_type });
826 self.globals_by_type
827 .entry(global_type)
828 .or_insert_with(|| Box::new(G::default()))
829 .downcast_mut::<G>()
830 .unwrap()
831 }
832
833 /// Set the value of the global of the given type.
834 pub fn set_global<G: Any>(&mut self, global: G) {
835 let global_type = TypeId::of::<G>();
836 self.push_effect(Effect::NotifyGlobalObservers { global_type });
837 self.globals_by_type.insert(global_type, Box::new(global));
838 }
839
840 /// Clear all stored globals. Does not notify global observers.
841 #[cfg(any(test, feature = "test-support"))]
842 pub fn clear_globals(&mut self) {
843 self.globals_by_type.drain();
844 }
845
846 /// Remove the global of the given type from the app context. Does not notify global observers.
847 #[cfg(any(test, feature = "test-support"))]
848 pub fn remove_global<G: Any>(&mut self) -> G {
849 let global_type = TypeId::of::<G>();
850 *self
851 .globals_by_type
852 .remove(&global_type)
853 .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
854 .downcast()
855 .unwrap()
856 }
857
858 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
859 /// your closure with mutable access to the `AppContext` and the global simultaneously.
860 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
861 let mut global = self.lease_global::<G>();
862 let result = f(&mut global, self);
863 self.end_global_lease(global);
864 result
865 }
866
867 /// Register a callback to be invoked when a global of the given type is updated.
868 pub fn observe_global<G: 'static>(
869 &mut self,
870 mut f: impl FnMut(&mut Self) + 'static,
871 ) -> Subscription {
872 self.global_observers.insert(
873 TypeId::of::<G>(),
874 Box::new(move |cx| {
875 f(cx);
876 true
877 }),
878 )
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 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 }
914
915 pub fn observe_release<E, T>(
916 &mut self,
917 handle: &E,
918 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
919 ) -> Subscription
920 where
921 E: Entity<T>,
922 T: 'static,
923 {
924 self.release_listeners.insert(
925 handle.entity_id(),
926 Box::new(move |entity, cx| {
927 let entity = entity.downcast_mut().expect("invalid entity type");
928 on_release(entity, cx)
929 }),
930 )
931 }
932
933 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
934 self.text_style_stack.push(text_style);
935 }
936
937 pub(crate) fn pop_text_style(&mut self) {
938 self.text_style_stack.pop();
939 }
940
941 /// Register key bindings.
942 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
943 self.keymap.lock().add_bindings(bindings);
944 self.pending_effects.push_back(Effect::Refresh);
945 }
946
947 /// Register a global listener for actions invoked via the keyboard.
948 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
949 self.global_action_listeners
950 .entry(TypeId::of::<A>())
951 .or_default()
952 .push(Box::new(move |action, phase, cx| {
953 if phase == DispatchPhase::Bubble {
954 let action = action.as_any().downcast_ref().unwrap();
955 listener(action, cx)
956 }
957 }));
958 }
959
960 /// Event handlers propagate events by default. Call this method to stop dispatching to
961 /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
962 /// the opposite of [propagate]. It's also possible to cancel a call to [propagate] by
963 /// calling this method before effects are flushed.
964 pub fn stop_propagation(&mut self) {
965 self.propagate_event = false;
966 }
967
968 /// Action handlers stop propagation by default during the bubble phase of action dispatch
969 /// dispatching to action handlers higher in the element tree. This is the opposite of
970 /// [stop_propagation]. It's also possible to cancel a call to [stop_propagate] by calling
971 /// this method before effects are flushed.
972 pub fn propagate(&mut self) {
973 self.propagate_event = true;
974 }
975
976 pub fn build_action(
977 &self,
978 name: &str,
979 data: Option<serde_json::Value>,
980 ) -> Result<Box<dyn Action>> {
981 self.actions.build_action(name, data)
982 }
983
984 pub fn all_action_names(&self) -> &[SharedString] {
985 self.actions.all_action_names()
986 }
987
988 pub fn on_app_quit<Fut>(
989 &mut self,
990 mut on_quit: impl FnMut(&mut AppContext) -> Fut + 'static,
991 ) -> Subscription
992 where
993 Fut: 'static + Future<Output = ()>,
994 {
995 self.quit_observers.insert(
996 (),
997 Box::new(move |cx| {
998 let future = on_quit(cx);
999 async move { future.await }.boxed_local()
1000 }),
1001 )
1002 }
1003}
1004
1005impl Context for AppContext {
1006 type Result<T> = T;
1007
1008 /// Build an entity that is owned by the application. The given function will be invoked with
1009 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
1010 /// which can be used to access the entity in a context.
1011 fn build_model<T: 'static>(
1012 &mut self,
1013 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1014 ) -> Model<T> {
1015 self.update(|cx| {
1016 let slot = cx.entities.reserve();
1017 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
1018 cx.entities.insert(slot, entity)
1019 })
1020 }
1021
1022 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
1023 /// entity along with a `ModelContext` for the entity.
1024 fn update_model<T: 'static, R>(
1025 &mut self,
1026 model: &Model<T>,
1027 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1028 ) -> R {
1029 self.update(|cx| {
1030 let mut entity = cx.entities.lease(model);
1031 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
1032 cx.entities.end_lease(entity);
1033 result
1034 })
1035 }
1036
1037 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
1038 where
1039 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1040 {
1041 self.update(|cx| {
1042 let mut window = cx
1043 .windows
1044 .get_mut(handle.id)
1045 .ok_or_else(|| anyhow!("window not found"))?
1046 .take()
1047 .unwrap();
1048
1049 let root_view = window.root_view.clone().unwrap();
1050 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
1051
1052 if !window.removed {
1053 cx.windows
1054 .get_mut(handle.id)
1055 .ok_or_else(|| anyhow!("window not found"))?
1056 .replace(window);
1057 }
1058
1059 Ok(result)
1060 })
1061 }
1062
1063 fn read_model<T, R>(
1064 &self,
1065 handle: &Model<T>,
1066 read: impl FnOnce(&T, &AppContext) -> R,
1067 ) -> Self::Result<R>
1068 where
1069 T: 'static,
1070 {
1071 let entity = self.entities.read(handle);
1072 read(entity, self)
1073 }
1074
1075 fn read_window<T, R>(
1076 &self,
1077 window: &WindowHandle<T>,
1078 read: impl FnOnce(View<T>, &AppContext) -> R,
1079 ) -> Result<R>
1080 where
1081 T: 'static,
1082 {
1083 let window = self
1084 .windows
1085 .get(window.id)
1086 .ok_or_else(|| anyhow!("window not found"))?
1087 .as_ref()
1088 .unwrap();
1089
1090 let root_view = window.root_view.clone().unwrap();
1091 let view = root_view
1092 .downcast::<T>()
1093 .map_err(|_| anyhow!("root view's type has changed"))?;
1094
1095 Ok(read(view, self))
1096 }
1097}
1098
1099/// These effects are processed at the end of each application update cycle.
1100pub(crate) enum Effect {
1101 Notify {
1102 emitter: EntityId,
1103 },
1104 Emit {
1105 emitter: EntityId,
1106 event_type: TypeId,
1107 event: Box<dyn Any>,
1108 },
1109 FocusChanged {
1110 window_handle: AnyWindowHandle,
1111 focused: Option<FocusId>,
1112 },
1113 Refresh,
1114 NotifyGlobalObservers {
1115 global_type: TypeId,
1116 },
1117 Defer {
1118 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
1119 },
1120}
1121
1122/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
1123pub(crate) struct GlobalLease<G: 'static> {
1124 global: Box<dyn Any>,
1125 global_type: PhantomData<G>,
1126}
1127
1128impl<G: 'static> GlobalLease<G> {
1129 fn new(global: Box<dyn Any>) -> Self {
1130 GlobalLease {
1131 global,
1132 global_type: PhantomData,
1133 }
1134 }
1135}
1136
1137impl<G: 'static> Deref for GlobalLease<G> {
1138 type Target = G;
1139
1140 fn deref(&self) -> &Self::Target {
1141 self.global.downcast_ref().unwrap()
1142 }
1143}
1144
1145impl<G: 'static> DerefMut for GlobalLease<G> {
1146 fn deref_mut(&mut self) -> &mut Self::Target {
1147 self.global.downcast_mut().unwrap()
1148 }
1149}
1150
1151/// Contains state associated with an active drag operation, started by dragging an element
1152/// within the window or by dragging into the app from the underlying platform.
1153pub struct AnyDrag {
1154 pub view: AnyView,
1155 pub cursor_offset: Point<Pixels>,
1156}
1157
1158#[derive(Clone)]
1159pub(crate) struct AnyTooltip {
1160 pub view: AnyView,
1161 pub cursor_offset: Point<Pixels>,
1162}