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::*;
16use time::UtcOffset;
17
18use crate::{
19 current_platform, image_cache::ImageCache, init_app_menus, Action, ActionRegistry, Any,
20 AnyView, AnyWindowHandle, AppMetadata, AssetSource, BackgroundExecutor, ClipboardItem, Context,
21 DispatchPhase, DisplayId, Entity, EventEmitter, FocusEvent, FocusHandle, FocusId,
22 ForegroundExecutor, KeyBinding, Keymap, LayoutId, Menu, PathPromptOptions, Pixels, Platform,
23 PlatformDisplay, Point, Render, SharedString, SubscriberSet, Subscription, SvgRenderer, Task,
24 TextStyle, TextStyleRefinement, TextSystem, View, ViewContext, Window, WindowContext,
25 WindowHandle, WindowId,
26};
27use anyhow::{anyhow, Result};
28use collections::{HashMap, HashSet, VecDeque};
29use futures::{channel::oneshot, future::LocalBoxFuture, Future};
30use parking_lot::Mutex;
31use slotmap::SlotMap;
32use std::{
33 any::{type_name, TypeId},
34 cell::{Ref, RefCell, RefMut},
35 marker::PhantomData,
36 mem,
37 ops::{Deref, DerefMut},
38 path::{Path, PathBuf},
39 rc::{Rc, Weak},
40 sync::{atomic::Ordering::SeqCst, Arc},
41 time::Duration,
42};
43use util::{
44 http::{self, HttpClient},
45 ResultExt,
46};
47
48/// Temporary(?) wrapper around RefCell<AppContext> to help us debug any double borrows.
49/// Strongly consider removing after stabilization.
50pub struct AppCell {
51 app: RefCell<AppContext>,
52}
53
54impl AppCell {
55 #[track_caller]
56 pub fn borrow(&self) -> AppRef {
57 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
58 let thread_id = std::thread::current().id();
59 eprintln!("borrowed {thread_id:?}");
60 }
61 AppRef(self.app.borrow())
62 }
63
64 #[track_caller]
65 pub fn borrow_mut(&self) -> AppRefMut {
66 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
67 let thread_id = std::thread::current().id();
68 eprintln!("borrowed {thread_id:?}");
69 }
70 AppRefMut(self.app.borrow_mut())
71 }
72}
73
74#[derive(Deref, DerefMut)]
75pub struct AppRef<'a>(Ref<'a, AppContext>);
76
77impl<'a> Drop for AppRef<'a> {
78 fn drop(&mut self) {
79 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
80 let thread_id = std::thread::current().id();
81 eprintln!("dropped borrow from {thread_id:?}");
82 }
83 }
84}
85
86#[derive(Deref, DerefMut)]
87pub struct AppRefMut<'a>(RefMut<'a, AppContext>);
88
89impl<'a> Drop for AppRefMut<'a> {
90 fn drop(&mut self) {
91 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
92 let thread_id = std::thread::current().id();
93 eprintln!("dropped {thread_id:?}");
94 }
95 }
96}
97
98pub struct App(Rc<AppCell>);
99
100/// Represents an application before it is fully launched. Once your app is
101/// configured, you'll start the app with `App::run`.
102impl App {
103 /// Builds an app with the given asset source.
104 pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
105 Self(AppContext::new(
106 current_platform(),
107 asset_source,
108 http::client(),
109 ))
110 }
111
112 /// Start the application. The provided callback will be called once the
113 /// app is fully launched.
114 pub fn run<F>(self, on_finish_launching: F)
115 where
116 F: 'static + FnOnce(&mut AppContext),
117 {
118 let this = self.0.clone();
119 let platform = self.0.borrow().platform.clone();
120 platform.run(Box::new(move || {
121 let cx = &mut *this.borrow_mut();
122 on_finish_launching(cx);
123 }));
124 }
125
126 /// Register a handler to be invoked when the platform instructs the application
127 /// to open one or more URLs.
128 pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
129 where
130 F: 'static + FnMut(Vec<String>, &mut AppContext),
131 {
132 let this = Rc::downgrade(&self.0);
133 self.0.borrow().platform.on_open_urls(Box::new(move |urls| {
134 if let Some(app) = this.upgrade() {
135 callback(urls, &mut *app.borrow_mut());
136 }
137 }));
138 self
139 }
140
141 pub fn on_reopen<F>(&self, mut callback: F) -> &Self
142 where
143 F: 'static + FnMut(&mut AppContext),
144 {
145 let this = Rc::downgrade(&self.0);
146 self.0.borrow_mut().platform.on_reopen(Box::new(move || {
147 if let Some(app) = this.upgrade() {
148 callback(&mut app.borrow_mut());
149 }
150 }));
151 self
152 }
153
154 pub fn metadata(&self) -> AppMetadata {
155 self.0.borrow().app_metadata.clone()
156 }
157
158 pub fn background_executor(&self) -> BackgroundExecutor {
159 self.0.borrow().background_executor.clone()
160 }
161
162 pub fn foreground_executor(&self) -> ForegroundExecutor {
163 self.0.borrow().foreground_executor.clone()
164 }
165
166 pub fn text_system(&self) -> Arc<TextSystem> {
167 self.0.borrow().text_system.clone()
168 }
169}
170
171pub(crate) type FrameCallback = Box<dyn FnOnce(&mut AppContext)>;
172type Handler = Box<dyn FnMut(&mut AppContext) -> bool + 'static>;
173type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + 'static>;
174type QuitHandler = Box<dyn FnOnce(&mut AppContext) -> LocalBoxFuture<'static, ()> + 'static>;
175type ReleaseListener = Box<dyn FnOnce(&mut dyn Any, &mut AppContext) + 'static>;
176type NewViewListener = Box<dyn FnMut(AnyView, &mut WindowContext) + 'static>;
177
178// struct FrameConsumer {
179// next_frame_callbacks: Vec<FrameCallback>,
180// task: Task<()>,
181// display_linker
182// }
183
184pub struct AppContext {
185 pub(crate) this: Weak<AppCell>,
186 pub(crate) platform: Rc<dyn Platform>,
187 app_metadata: AppMetadata,
188 text_system: Arc<TextSystem>,
189 flushing_effects: bool,
190 pending_updates: usize,
191 pub(crate) actions: Rc<ActionRegistry>,
192 pub(crate) active_drag: Option<AnyDrag>,
193 pub(crate) active_tooltip: Option<AnyTooltip>,
194 pub(crate) next_frame_callbacks: HashMap<DisplayId, Vec<FrameCallback>>,
195 pub(crate) frame_consumers: HashMap<DisplayId, Task<()>>,
196 pub(crate) background_executor: BackgroundExecutor,
197 pub(crate) foreground_executor: ForegroundExecutor,
198 pub(crate) svg_renderer: SvgRenderer,
199 asset_source: Arc<dyn AssetSource>,
200 pub(crate) image_cache: ImageCache,
201 pub(crate) text_style_stack: Vec<TextStyleRefinement>,
202 pub(crate) globals_by_type: HashMap<TypeId, Box<dyn Any>>,
203 pub(crate) entities: EntityMap,
204 pub(crate) new_view_observers: SubscriberSet<TypeId, NewViewListener>,
205 pub(crate) windows: SlotMap<WindowId, Option<Window>>,
206 pub(crate) keymap: Arc<Mutex<Keymap>>,
207 pub(crate) global_action_listeners:
208 HashMap<TypeId, Vec<Rc<dyn Fn(&dyn Any, DispatchPhase, &mut Self)>>>,
209 pending_effects: VecDeque<Effect>,
210 pub(crate) pending_notifications: HashSet<EntityId>,
211 pub(crate) pending_global_notifications: HashSet<TypeId>,
212 pub(crate) observers: SubscriberSet<EntityId, Handler>,
213 // TypeId is the type of the event that the listener callback expects
214 pub(crate) event_listeners: SubscriberSet<EntityId, (TypeId, Listener)>,
215 pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
216 pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
217 pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
218 pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
219 pub(crate) propagate_event: bool,
220}
221
222impl AppContext {
223 pub(crate) fn new(
224 platform: Rc<dyn Platform>,
225 asset_source: Arc<dyn AssetSource>,
226 http_client: Arc<dyn HttpClient>,
227 ) -> Rc<AppCell> {
228 let executor = platform.background_executor();
229 let foreground_executor = platform.foreground_executor();
230 assert!(
231 executor.is_main_thread(),
232 "must construct App on main thread"
233 );
234
235 let text_system = Arc::new(TextSystem::new(platform.text_system()));
236 let entities = EntityMap::new();
237
238 let app_metadata = AppMetadata {
239 os_name: platform.os_name(),
240 os_version: platform.os_version().ok(),
241 app_version: platform.app_version().ok(),
242 };
243
244 let app = Rc::new_cyclic(|this| AppCell {
245 app: RefCell::new(AppContext {
246 this: this.clone(),
247 platform: platform.clone(),
248 app_metadata,
249 text_system,
250 actions: Rc::new(ActionRegistry::default()),
251 flushing_effects: false,
252 pending_updates: 0,
253 active_drag: None,
254 active_tooltip: None,
255 next_frame_callbacks: HashMap::default(),
256 frame_consumers: HashMap::default(),
257 background_executor: executor,
258 foreground_executor,
259 svg_renderer: SvgRenderer::new(asset_source.clone()),
260 asset_source,
261 image_cache: ImageCache::new(http_client),
262 text_style_stack: Vec::new(),
263 globals_by_type: HashMap::default(),
264 entities,
265 new_view_observers: SubscriberSet::new(),
266 windows: SlotMap::with_key(),
267 keymap: Arc::new(Mutex::new(Keymap::default())),
268 global_action_listeners: HashMap::default(),
269 pending_effects: VecDeque::new(),
270 pending_notifications: HashSet::default(),
271 pending_global_notifications: HashSet::default(),
272 observers: SubscriberSet::new(),
273 event_listeners: SubscriberSet::new(),
274 release_listeners: SubscriberSet::new(),
275 global_observers: SubscriberSet::new(),
276 quit_observers: SubscriberSet::new(),
277 layout_id_buffer: Default::default(),
278 propagate_event: true,
279 }),
280 });
281
282 init_app_menus(platform.as_ref(), &mut *app.borrow_mut());
283
284 platform.on_quit(Box::new({
285 let cx = app.clone();
286 move || {
287 cx.borrow_mut().shutdown();
288 }
289 }));
290
291 app
292 }
293
294 /// Quit the application gracefully. Handlers registered with `ModelContext::on_app_quit`
295 /// will be given 100ms to complete before exiting.
296 pub fn shutdown(&mut self) {
297 let mut futures = Vec::new();
298
299 for observer in self.quit_observers.remove(&()) {
300 futures.push(observer(self));
301 }
302
303 self.windows.clear();
304 self.flush_effects();
305
306 let futures = futures::future::join_all(futures);
307 if self
308 .background_executor
309 .block_with_timeout(Duration::from_millis(100), futures)
310 .is_err()
311 {
312 log::error!("timed out waiting on app_will_quit");
313 }
314 }
315
316 pub fn quit(&mut self) {
317 self.platform.quit();
318 }
319
320 pub fn app_metadata(&self) -> AppMetadata {
321 self.app_metadata.clone()
322 }
323
324 /// Schedules all windows in the application to be redrawn. This can be called
325 /// multiple times in an update cycle and still result in a single redraw.
326 pub fn refresh(&mut self) {
327 self.pending_effects.push_back(Effect::Refresh);
328 }
329 pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
330 self.pending_updates += 1;
331 let result = update(self);
332 if !self.flushing_effects && self.pending_updates == 1 {
333 self.flushing_effects = true;
334 self.flush_effects();
335 self.flushing_effects = false;
336 }
337 self.pending_updates -= 1;
338 result
339 }
340
341 pub fn observe<W, E>(
342 &mut self,
343 entity: &E,
344 mut on_notify: impl FnMut(E, &mut AppContext) + 'static,
345 ) -> Subscription
346 where
347 W: 'static,
348 E: Entity<W>,
349 {
350 self.observe_internal(entity, move |e, cx| {
351 on_notify(e, cx);
352 true
353 })
354 }
355
356 pub fn observe_internal<W, E>(
357 &mut self,
358 entity: &E,
359 mut on_notify: impl FnMut(E, &mut AppContext) -> bool + 'static,
360 ) -> Subscription
361 where
362 W: 'static,
363 E: Entity<W>,
364 {
365 let entity_id = entity.entity_id();
366 let handle = entity.downgrade();
367 let (subscription, activate) = self.observers.insert(
368 entity_id,
369 Box::new(move |cx| {
370 if let Some(handle) = E::upgrade_from(&handle) {
371 on_notify(handle, cx)
372 } else {
373 false
374 }
375 }),
376 );
377 self.defer(move |_| activate());
378 subscription
379 }
380
381 pub fn subscribe<T, E, Evt>(
382 &mut self,
383 entity: &E,
384 mut on_event: impl FnMut(E, &Evt, &mut AppContext) + 'static,
385 ) -> Subscription
386 where
387 T: 'static + EventEmitter<Evt>,
388 E: Entity<T>,
389 Evt: 'static,
390 {
391 self.subscribe_internal(entity, move |entity, event, cx| {
392 on_event(entity, event, cx);
393 true
394 })
395 }
396
397 pub(crate) fn subscribe_internal<T, E, Evt>(
398 &mut self,
399 entity: &E,
400 mut on_event: impl FnMut(E, &Evt, &mut AppContext) -> bool + 'static,
401 ) -> Subscription
402 where
403 T: 'static + EventEmitter<Evt>,
404 E: Entity<T>,
405 Evt: 'static,
406 {
407 let entity_id = entity.entity_id();
408 let entity = entity.downgrade();
409 let (subscription, activate) = self.event_listeners.insert(
410 entity_id,
411 (
412 TypeId::of::<Evt>(),
413 Box::new(move |event, cx| {
414 let event: &Evt = event.downcast_ref().expect("invalid event type");
415 if let Some(handle) = E::upgrade_from(&entity) {
416 on_event(handle, event, cx)
417 } else {
418 false
419 }
420 }),
421 ),
422 );
423 self.defer(move |_| activate());
424 subscription
425 }
426
427 pub fn windows(&self) -> Vec<AnyWindowHandle> {
428 self.windows
429 .values()
430 .filter_map(|window| Some(window.as_ref()?.handle.clone()))
431 .collect()
432 }
433
434 pub fn active_window(&self) -> Option<AnyWindowHandle> {
435 self.platform.active_window()
436 }
437
438 /// Opens a new window with the given option and the root view returned by the given function.
439 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
440 /// functionality.
441 pub fn open_window<V: 'static + Render>(
442 &mut self,
443 options: crate::WindowOptions,
444 build_root_view: impl FnOnce(&mut WindowContext) -> View<V>,
445 ) -> WindowHandle<V> {
446 self.update(|cx| {
447 let id = cx.windows.insert(None);
448 let handle = WindowHandle::new(id);
449 let mut window = Window::new(handle.into(), options, cx);
450 let root_view = build_root_view(&mut WindowContext::new(cx, &mut window));
451 window.root_view.replace(root_view.into());
452 cx.windows.get_mut(id).unwrap().replace(window);
453 handle
454 })
455 }
456
457 /// Instructs the platform to activate the application by bringing it to the foreground.
458 pub fn activate(&self, ignoring_other_apps: bool) {
459 self.platform.activate(ignoring_other_apps);
460 }
461
462 pub fn hide(&self) {
463 self.platform.hide();
464 }
465
466 pub fn hide_other_apps(&self) {
467 self.platform.hide_other_apps();
468 }
469
470 pub fn unhide_other_apps(&self) {
471 self.platform.unhide_other_apps();
472 }
473
474 /// Returns the list of currently active displays.
475 pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
476 self.platform.displays()
477 }
478
479 /// Writes data to the platform clipboard.
480 pub fn write_to_clipboard(&self, item: ClipboardItem) {
481 self.platform.write_to_clipboard(item)
482 }
483
484 /// Reads data from the platform clipboard.
485 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
486 self.platform.read_from_clipboard()
487 }
488
489 /// Writes credentials to the platform keychain.
490 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
491 self.platform.write_credentials(url, username, password)
492 }
493
494 /// Reads credentials from the platform keychain.
495 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
496 self.platform.read_credentials(url)
497 }
498
499 /// Deletes credentials from the platform keychain.
500 pub fn delete_credentials(&self, url: &str) -> Result<()> {
501 self.platform.delete_credentials(url)
502 }
503
504 /// Directs the platform's default browser to open the given URL.
505 pub fn open_url(&self, url: &str) {
506 self.platform.open_url(url);
507 }
508
509 pub fn app_path(&self) -> Result<PathBuf> {
510 self.platform.app_path()
511 }
512
513 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
514 self.platform.path_for_auxiliary_executable(name)
515 }
516
517 pub fn prompt_for_paths(
518 &self,
519 options: PathPromptOptions,
520 ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
521 self.platform.prompt_for_paths(options)
522 }
523
524 pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
525 self.platform.prompt_for_new_path(directory)
526 }
527
528 pub fn reveal_path(&self, path: &Path) {
529 self.platform.reveal_path(path)
530 }
531
532 pub fn should_auto_hide_scrollbars(&self) -> bool {
533 self.platform.should_auto_hide_scrollbars()
534 }
535
536 pub fn restart(&self) {
537 self.platform.restart()
538 }
539
540 pub fn local_timezone(&self) -> UtcOffset {
541 self.platform.local_timezone()
542 }
543
544 pub(crate) fn push_effect(&mut self, effect: Effect) {
545 match &effect {
546 Effect::Notify { emitter } => {
547 if !self.pending_notifications.insert(*emitter) {
548 return;
549 }
550 }
551 Effect::NotifyGlobalObservers { global_type } => {
552 if !self.pending_global_notifications.insert(*global_type) {
553 return;
554 }
555 }
556 _ => {}
557 };
558
559 self.pending_effects.push_back(effect);
560 }
561
562 /// Called at the end of AppContext::update to complete any side effects
563 /// such as notifying observers, emitting events, etc. Effects can themselves
564 /// cause effects, so we continue looping until all effects are processed.
565 fn flush_effects(&mut self) {
566 loop {
567 self.release_dropped_entities();
568 self.release_dropped_focus_handles();
569 if let Some(effect) = self.pending_effects.pop_front() {
570 match effect {
571 Effect::Notify { emitter } => {
572 self.apply_notify_effect(emitter);
573 }
574 Effect::Emit {
575 emitter,
576 event_type,
577 event,
578 } => self.apply_emit_effect(emitter, event_type, event),
579 Effect::FocusChanged {
580 window_handle,
581 focused,
582 } => {
583 self.apply_focus_changed_effect(window_handle, focused);
584 }
585 Effect::Refresh => {
586 self.apply_refresh_effect();
587 }
588 Effect::NotifyGlobalObservers { global_type } => {
589 self.apply_notify_global_observers_effect(global_type);
590 }
591 Effect::Defer { callback } => {
592 self.apply_defer_effect(callback);
593 }
594 }
595 } else {
596 break;
597 }
598 }
599
600 let dirty_window_ids = self
601 .windows
602 .iter()
603 .filter_map(|(_, window)| {
604 let window = window.as_ref()?;
605 if window.dirty {
606 Some(window.handle.clone())
607 } else {
608 None
609 }
610 })
611 .collect::<SmallVec<[_; 8]>>();
612
613 for dirty_window_handle in dirty_window_ids {
614 dirty_window_handle.update(self, |_, cx| cx.draw()).unwrap();
615 }
616 }
617
618 /// Repeatedly called during `flush_effects` to release any entities whose
619 /// reference count has become zero. We invoke any release observers before dropping
620 /// each entity.
621 fn release_dropped_entities(&mut self) {
622 loop {
623 let dropped = self.entities.take_dropped();
624 if dropped.is_empty() {
625 break;
626 }
627
628 for (entity_id, mut entity) in dropped {
629 self.observers.remove(&entity_id);
630 self.event_listeners.remove(&entity_id);
631 for release_callback in self.release_listeners.remove(&entity_id) {
632 release_callback(entity.as_mut(), self);
633 }
634 }
635 }
636 }
637
638 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
639 /// For now, we simply blur the window if this happens, but we may want to support invoking
640 /// a window blur handler to restore focus to some logical element.
641 fn release_dropped_focus_handles(&mut self) {
642 for window_handle in self.windows() {
643 window_handle
644 .update(self, |_, cx| {
645 let mut blur_window = false;
646 let focus = cx.window.focus;
647 cx.window.focus_handles.write().retain(|handle_id, count| {
648 if count.load(SeqCst) == 0 {
649 if focus == Some(handle_id) {
650 blur_window = true;
651 }
652 false
653 } else {
654 true
655 }
656 });
657
658 if blur_window {
659 cx.blur();
660 }
661 })
662 .unwrap();
663 }
664 }
665
666 fn apply_notify_effect(&mut self, emitter: EntityId) {
667 self.pending_notifications.remove(&emitter);
668
669 self.observers
670 .clone()
671 .retain(&emitter, |handler| handler(self));
672 }
673
674 fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: Box<dyn Any>) {
675 self.event_listeners
676 .clone()
677 .retain(&emitter, |(stored_type, handler)| {
678 if *stored_type == event_type {
679 handler(event.as_ref(), self)
680 } else {
681 true
682 }
683 });
684 }
685
686 fn apply_focus_changed_effect(
687 &mut self,
688 window_handle: AnyWindowHandle,
689 focused: Option<FocusId>,
690 ) {
691 window_handle
692 .update(self, |_, cx| {
693 // The window might change focus multiple times in an effect cycle.
694 // We only honor effects for the most recently focused handle.
695 if cx.window.focus == focused {
696 // if someone calls focus multiple times in one frame with the same handle
697 // the first apply_focus_changed_effect will have taken the last blur already
698 // and run the rest of this, so we can return.
699 let Some(last_blur) = cx.window.last_blur.take() else {
700 return;
701 };
702
703 let focused = focused
704 .map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
705
706 let blurred =
707 last_blur.and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
708
709 let focus_changed = focused.is_some() || blurred.is_some();
710 let event = FocusEvent { focused, blurred };
711
712 let mut listeners = mem::take(&mut cx.window.rendered_frame.focus_listeners);
713 if focus_changed {
714 for listener in &mut listeners {
715 listener(&event, cx);
716 }
717 }
718 cx.window.rendered_frame.focus_listeners = listeners;
719
720 if focus_changed {
721 cx.window
722 .focus_listeners
723 .clone()
724 .retain(&(), |listener| listener(&event, cx));
725 }
726 }
727 })
728 .ok();
729 }
730
731 fn apply_refresh_effect(&mut self) {
732 for window in self.windows.values_mut() {
733 if let Some(window) = window.as_mut() {
734 window.dirty = true;
735 }
736 }
737 }
738
739 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
740 self.pending_global_notifications.remove(&type_id);
741 self.global_observers
742 .clone()
743 .retain(&type_id, |observer| observer(self));
744 }
745
746 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
747 callback(self);
748 }
749
750 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
751 /// so it can be held across `await` points.
752 pub fn to_async(&self) -> AsyncAppContext {
753 AsyncAppContext {
754 app: unsafe { mem::transmute(self.this.clone()) },
755 background_executor: self.background_executor.clone(),
756 foreground_executor: self.foreground_executor.clone(),
757 }
758 }
759
760 /// Obtains a reference to the executor, which can be used to spawn futures.
761 pub fn background_executor(&self) -> &BackgroundExecutor {
762 &self.background_executor
763 }
764
765 /// Obtains a reference to the executor, which can be used to spawn futures.
766 pub fn foreground_executor(&self) -> &ForegroundExecutor {
767 &self.foreground_executor
768 }
769
770 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
771 /// with AsyncAppContext, which allows the application state to be accessed across await points.
772 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
773 where
774 Fut: Future<Output = R> + 'static,
775 R: 'static,
776 {
777 self.foreground_executor.spawn(f(self.to_async()))
778 }
779
780 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
781 /// that are currently on the stack to be returned to the app.
782 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
783 self.push_effect(Effect::Defer {
784 callback: Box::new(f),
785 });
786 }
787
788 /// Accessor for the application's asset source, which is provided when constructing the `App`.
789 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
790 &self.asset_source
791 }
792
793 /// Accessor for the text system.
794 pub fn text_system(&self) -> &Arc<TextSystem> {
795 &self.text_system
796 }
797
798 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
799 pub fn text_style(&self) -> TextStyle {
800 let mut style = TextStyle::default();
801 for refinement in &self.text_style_stack {
802 style.refine(refinement);
803 }
804 style
805 }
806
807 /// Check whether a global of the given type has been assigned.
808 pub fn has_global<G: 'static>(&self) -> bool {
809 self.globals_by_type.contains_key(&TypeId::of::<G>())
810 }
811
812 /// Access the global of the given type. Panics if a global for that type has not been assigned.
813 #[track_caller]
814 pub fn global<G: 'static>(&self) -> &G {
815 self.globals_by_type
816 .get(&TypeId::of::<G>())
817 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
818 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
819 .unwrap()
820 }
821
822 /// Access the global of the given type if a value has been assigned.
823 pub fn try_global<G: 'static>(&self) -> Option<&G> {
824 self.globals_by_type
825 .get(&TypeId::of::<G>())
826 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
827 }
828
829 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
830 #[track_caller]
831 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
832 let global_type = TypeId::of::<G>();
833 self.push_effect(Effect::NotifyGlobalObservers { global_type });
834 self.globals_by_type
835 .get_mut(&global_type)
836 .and_then(|any_state| any_state.downcast_mut::<G>())
837 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
838 .unwrap()
839 }
840
841 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
842 /// yet been assigned.
843 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
844 let global_type = TypeId::of::<G>();
845 self.push_effect(Effect::NotifyGlobalObservers { global_type });
846 self.globals_by_type
847 .entry(global_type)
848 .or_insert_with(|| Box::new(G::default()))
849 .downcast_mut::<G>()
850 .unwrap()
851 }
852
853 /// Set the value of the global of the given type.
854 pub fn set_global<G: Any>(&mut self, global: G) {
855 let global_type = TypeId::of::<G>();
856 self.push_effect(Effect::NotifyGlobalObservers { global_type });
857 self.globals_by_type.insert(global_type, Box::new(global));
858 }
859
860 /// Clear all stored globals. Does not notify global observers.
861 #[cfg(any(test, feature = "test-support"))]
862 pub fn clear_globals(&mut self) {
863 self.globals_by_type.drain();
864 }
865
866 /// Remove the global of the given type from the app context. Does not notify global observers.
867 pub fn remove_global<G: Any>(&mut self) -> G {
868 let global_type = TypeId::of::<G>();
869 *self
870 .globals_by_type
871 .remove(&global_type)
872 .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
873 .downcast()
874 .unwrap()
875 }
876
877 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
878 /// your closure with mutable access to the `AppContext` and the global simultaneously.
879 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
880 let mut global = self.lease_global::<G>();
881 let result = f(&mut global, self);
882 self.end_global_lease(global);
883 result
884 }
885
886 /// Register a callback to be invoked when a global of the given type is updated.
887 pub fn observe_global<G: 'static>(
888 &mut self,
889 mut f: impl FnMut(&mut Self) + 'static,
890 ) -> Subscription {
891 let (subscription, activate) = self.global_observers.insert(
892 TypeId::of::<G>(),
893 Box::new(move |cx| {
894 f(cx);
895 true
896 }),
897 );
898 self.defer(move |_| activate());
899 subscription
900 }
901
902 /// Move the global of the given type to the stack.
903 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
904 GlobalLease::new(
905 self.globals_by_type
906 .remove(&TypeId::of::<G>())
907 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
908 .unwrap(),
909 )
910 }
911
912 /// Restore the global of the given type after it is moved to the stack.
913 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
914 let global_type = TypeId::of::<G>();
915 self.push_effect(Effect::NotifyGlobalObservers { global_type });
916 self.globals_by_type.insert(global_type, lease.global);
917 }
918
919 pub fn observe_new_views<V: 'static>(
920 &mut self,
921 on_new: impl 'static + Fn(&mut V, &mut ViewContext<V>),
922 ) -> Subscription {
923 let (subscription, activate) = self.new_view_observers.insert(
924 TypeId::of::<V>(),
925 Box::new(move |any_view: AnyView, cx: &mut WindowContext| {
926 any_view
927 .downcast::<V>()
928 .unwrap()
929 .update(cx, |view_state, cx| {
930 on_new(view_state, cx);
931 })
932 }),
933 );
934 activate();
935 subscription
936 }
937
938 pub fn observe_release<E, T>(
939 &mut self,
940 handle: &E,
941 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
942 ) -> Subscription
943 where
944 E: Entity<T>,
945 T: 'static,
946 {
947 let (subscription, activate) = self.release_listeners.insert(
948 handle.entity_id(),
949 Box::new(move |entity, cx| {
950 let entity = entity.downcast_mut().expect("invalid entity type");
951 on_release(entity, cx)
952 }),
953 );
954 activate();
955 subscription
956 }
957
958 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
959 self.text_style_stack.push(text_style);
960 }
961
962 pub(crate) fn pop_text_style(&mut self) {
963 self.text_style_stack.pop();
964 }
965
966 /// Register key bindings.
967 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
968 self.keymap.lock().add_bindings(bindings);
969 self.pending_effects.push_back(Effect::Refresh);
970 }
971
972 /// Register a global listener for actions invoked via the keyboard.
973 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
974 self.global_action_listeners
975 .entry(TypeId::of::<A>())
976 .or_default()
977 .push(Rc::new(move |action, phase, cx| {
978 if phase == DispatchPhase::Bubble {
979 let action = action.downcast_ref().unwrap();
980 listener(action, cx)
981 }
982 }));
983 }
984
985 /// Event handlers propagate events by default. Call this method to stop dispatching to
986 /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
987 /// the opposite of [propagate]. It's also possible to cancel a call to [propagate] by
988 /// calling this method before effects are flushed.
989 pub fn stop_propagation(&mut self) {
990 self.propagate_event = false;
991 }
992
993 /// Action handlers stop propagation by default during the bubble phase of action dispatch
994 /// dispatching to action handlers higher in the element tree. This is the opposite of
995 /// [stop_propagation]. It's also possible to cancel a call to [stop_propagate] by calling
996 /// this method before effects are flushed.
997 pub fn propagate(&mut self) {
998 self.propagate_event = true;
999 }
1000
1001 pub fn build_action(
1002 &self,
1003 name: &str,
1004 data: Option<serde_json::Value>,
1005 ) -> Result<Box<dyn Action>> {
1006 self.actions.build_action(name, data)
1007 }
1008
1009 pub fn all_action_names(&self) -> &[SharedString] {
1010 self.actions.all_action_names()
1011 }
1012
1013 pub fn on_app_quit<Fut>(
1014 &mut self,
1015 mut on_quit: impl FnMut(&mut AppContext) -> Fut + 'static,
1016 ) -> Subscription
1017 where
1018 Fut: 'static + Future<Output = ()>,
1019 {
1020 let (subscription, activate) = self.quit_observers.insert(
1021 (),
1022 Box::new(move |cx| {
1023 let future = on_quit(cx);
1024 async move { future.await }.boxed_local()
1025 }),
1026 );
1027 activate();
1028 subscription
1029 }
1030
1031 pub(crate) fn clear_pending_keystrokes(&mut self) {
1032 for window in self.windows() {
1033 window
1034 .update(self, |_, cx| {
1035 cx.window
1036 .rendered_frame
1037 .dispatch_tree
1038 .clear_pending_keystrokes();
1039 cx.window
1040 .next_frame
1041 .dispatch_tree
1042 .clear_pending_keystrokes();
1043 })
1044 .ok();
1045 }
1046 }
1047
1048 pub fn is_action_available(&mut self, action: &dyn Action) -> bool {
1049 if let Some(window) = self.active_window() {
1050 if let Ok(window_action_available) =
1051 window.update(self, |_, cx| cx.is_action_available(action))
1052 {
1053 return window_action_available;
1054 }
1055 }
1056
1057 self.global_action_listeners
1058 .contains_key(&action.as_any().type_id())
1059 }
1060
1061 pub fn set_menus(&mut self, menus: Vec<Menu>) {
1062 self.platform.set_menus(menus, &self.keymap.lock());
1063 }
1064
1065 pub fn dispatch_action(&mut self, action: &dyn Action) {
1066 if let Some(active_window) = self.active_window() {
1067 active_window
1068 .update(self, |_, cx| cx.dispatch_action(action.boxed_clone()))
1069 .log_err();
1070 } else {
1071 self.propagate_event = true;
1072
1073 if let Some(mut global_listeners) = self
1074 .global_action_listeners
1075 .remove(&action.as_any().type_id())
1076 {
1077 for listener in &global_listeners {
1078 listener(action.as_any(), DispatchPhase::Capture, self);
1079 if !self.propagate_event {
1080 break;
1081 }
1082 }
1083
1084 global_listeners.extend(
1085 self.global_action_listeners
1086 .remove(&action.as_any().type_id())
1087 .unwrap_or_default(),
1088 );
1089
1090 self.global_action_listeners
1091 .insert(action.as_any().type_id(), global_listeners);
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.as_any(), 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
1119 pub fn has_active_drag(&self) -> bool {
1120 self.active_drag.is_some()
1121 }
1122}
1123
1124impl Context for AppContext {
1125 type Result<T> = T;
1126
1127 /// Build an entity that is owned by the application. The given function will be invoked with
1128 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
1129 /// which can be used to access the entity in a context.
1130 fn build_model<T: 'static>(
1131 &mut self,
1132 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1133 ) -> Model<T> {
1134 self.update(|cx| {
1135 let slot = cx.entities.reserve();
1136 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
1137 cx.entities.insert(slot, entity)
1138 })
1139 }
1140
1141 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
1142 /// entity along with a `ModelContext` for the entity.
1143 fn update_model<T: 'static, R>(
1144 &mut self,
1145 model: &Model<T>,
1146 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1147 ) -> R {
1148 self.update(|cx| {
1149 let mut entity = cx.entities.lease(model);
1150 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
1151 cx.entities.end_lease(entity);
1152 result
1153 })
1154 }
1155
1156 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
1157 where
1158 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1159 {
1160 self.update(|cx| {
1161 let mut window = cx
1162 .windows
1163 .get_mut(handle.id)
1164 .ok_or_else(|| anyhow!("window not found"))?
1165 .take()
1166 .unwrap();
1167
1168 let root_view = window.root_view.clone().unwrap();
1169 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
1170
1171 if window.removed {
1172 cx.windows.remove(handle.id);
1173 } else {
1174 cx.windows
1175 .get_mut(handle.id)
1176 .ok_or_else(|| anyhow!("window not found"))?
1177 .replace(window);
1178 }
1179
1180 Ok(result)
1181 })
1182 }
1183
1184 fn read_model<T, R>(
1185 &self,
1186 handle: &Model<T>,
1187 read: impl FnOnce(&T, &AppContext) -> R,
1188 ) -> Self::Result<R>
1189 where
1190 T: 'static,
1191 {
1192 let entity = self.entities.read(handle);
1193 read(entity, self)
1194 }
1195
1196 fn read_window<T, R>(
1197 &self,
1198 window: &WindowHandle<T>,
1199 read: impl FnOnce(View<T>, &AppContext) -> R,
1200 ) -> Result<R>
1201 where
1202 T: 'static,
1203 {
1204 let window = self
1205 .windows
1206 .get(window.id)
1207 .ok_or_else(|| anyhow!("window not found"))?
1208 .as_ref()
1209 .unwrap();
1210
1211 let root_view = window.root_view.clone().unwrap();
1212 let view = root_view
1213 .downcast::<T>()
1214 .map_err(|_| anyhow!("root view's type has changed"))?;
1215
1216 Ok(read(view, self))
1217 }
1218}
1219
1220/// These effects are processed at the end of each application update cycle.
1221pub(crate) enum Effect {
1222 Notify {
1223 emitter: EntityId,
1224 },
1225 Emit {
1226 emitter: EntityId,
1227 event_type: TypeId,
1228 event: Box<dyn Any>,
1229 },
1230 FocusChanged {
1231 window_handle: AnyWindowHandle,
1232 focused: Option<FocusId>,
1233 },
1234 Refresh,
1235 NotifyGlobalObservers {
1236 global_type: TypeId,
1237 },
1238 Defer {
1239 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
1240 },
1241}
1242
1243/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
1244pub(crate) struct GlobalLease<G: 'static> {
1245 global: Box<dyn Any>,
1246 global_type: PhantomData<G>,
1247}
1248
1249impl<G: 'static> GlobalLease<G> {
1250 fn new(global: Box<dyn Any>) -> Self {
1251 GlobalLease {
1252 global,
1253 global_type: PhantomData,
1254 }
1255 }
1256}
1257
1258impl<G: 'static> Deref for GlobalLease<G> {
1259 type Target = G;
1260
1261 fn deref(&self) -> &Self::Target {
1262 self.global.downcast_ref().unwrap()
1263 }
1264}
1265
1266impl<G: 'static> DerefMut for GlobalLease<G> {
1267 fn deref_mut(&mut self) -> &mut Self::Target {
1268 self.global.downcast_mut().unwrap()
1269 }
1270}
1271
1272/// Contains state associated with an active drag operation, started by dragging an element
1273/// within the window or by dragging into the app from the underlying platform.
1274pub struct AnyDrag {
1275 pub view: AnyView,
1276 pub cursor_offset: Point<Pixels>,
1277}
1278
1279#[derive(Clone)]
1280pub(crate) struct AnyTooltip {
1281 pub view: AnyView,
1282 pub cursor_offset: Point<Pixels>,
1283}