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, init_app_menus, Action, ActionRegistry, Any,
19 AnyView, AnyWindowHandle, AppMetadata, AssetSource, BackgroundExecutor, ClipboardItem, Context,
20 DispatchPhase, DisplayId, Entity, EventEmitter, FocusEvent, FocusHandle, FocusId,
21 ForegroundExecutor, KeyBinding, Keymap, LayoutId, Menu, PathPromptOptions, Pixels, Platform,
22 PlatformDisplay, Point, Render, SharedString, SubscriberSet, Subscription, SvgRenderer, Task,
23 TextStyle, TextStyleRefinement, TextSystem, View, ViewContext, Window, WindowContext,
24 WindowHandle, WindowId,
25};
26use anyhow::{anyhow, Result};
27use collections::{HashMap, HashSet, VecDeque};
28use futures::{channel::oneshot, future::LocalBoxFuture, Future};
29use parking_lot::Mutex;
30use slotmap::SlotMap;
31use std::{
32 any::{type_name, TypeId},
33 cell::{Ref, RefCell, RefMut},
34 marker::PhantomData,
35 mem,
36 ops::{Deref, DerefMut},
37 path::{Path, PathBuf},
38 rc::{Rc, Weak},
39 sync::{atomic::Ordering::SeqCst, Arc},
40 time::Duration,
41};
42use util::{
43 http::{self, HttpClient},
44 ResultExt,
45};
46
47/// Temporary(?) wrapper around RefCell<AppContext> to help us debug any double borrows.
48/// Strongly consider removing after stabilization.
49pub struct AppCell {
50 app: RefCell<AppContext>,
51}
52
53impl AppCell {
54 #[track_caller]
55 pub fn borrow(&self) -> AppRef {
56 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
57 let thread_id = std::thread::current().id();
58 eprintln!("borrowed {thread_id:?}");
59 }
60 AppRef(self.app.borrow())
61 }
62
63 #[track_caller]
64 pub fn borrow_mut(&self) -> AppRefMut {
65 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
66 let thread_id = std::thread::current().id();
67 eprintln!("borrowed {thread_id:?}");
68 }
69 AppRefMut(self.app.borrow_mut())
70 }
71}
72
73#[derive(Deref, DerefMut)]
74pub struct AppRef<'a>(Ref<'a, AppContext>);
75
76impl<'a> Drop for AppRef<'a> {
77 fn drop(&mut self) {
78 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
79 let thread_id = std::thread::current().id();
80 eprintln!("dropped borrow from {thread_id:?}");
81 }
82 }
83}
84
85#[derive(Deref, DerefMut)]
86pub struct AppRefMut<'a>(RefMut<'a, AppContext>);
87
88impl<'a> Drop for AppRefMut<'a> {
89 fn drop(&mut self) {
90 if let Some(_) = option_env!("TRACK_THREAD_BORROWS") {
91 let thread_id = std::thread::current().id();
92 eprintln!("dropped {thread_id:?}");
93 }
94 }
95}
96
97pub struct App(Rc<AppCell>);
98
99/// Represents an application before it is fully launched. Once your app is
100/// configured, you'll start the app with `App::run`.
101impl App {
102 /// Builds an app with the given asset source.
103 pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
104 Self(AppContext::new(
105 current_platform(),
106 asset_source,
107 http::client(),
108 ))
109 }
110
111 /// Start the application. The provided callback will be called once the
112 /// app is fully launched.
113 pub fn run<F>(self, on_finish_launching: F)
114 where
115 F: 'static + FnOnce(&mut AppContext),
116 {
117 let this = self.0.clone();
118 let platform = self.0.borrow().platform.clone();
119 platform.run(Box::new(move || {
120 let cx = &mut *this.borrow_mut();
121 on_finish_launching(cx);
122 }));
123 }
124
125 /// Register a handler to be invoked when the platform instructs the application
126 /// to open one or more URLs.
127 pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
128 where
129 F: 'static + FnMut(Vec<String>, &mut AppContext),
130 {
131 let this = Rc::downgrade(&self.0);
132 self.0.borrow().platform.on_open_urls(Box::new(move |urls| {
133 if let Some(app) = this.upgrade() {
134 callback(urls, &mut *app.borrow_mut());
135 }
136 }));
137 self
138 }
139
140 pub fn on_reopen<F>(&self, mut callback: F) -> &Self
141 where
142 F: 'static + FnMut(&mut AppContext),
143 {
144 let this = Rc::downgrade(&self.0);
145 self.0.borrow_mut().platform.on_reopen(Box::new(move || {
146 if let Some(app) = this.upgrade() {
147 callback(&mut app.borrow_mut());
148 }
149 }));
150 self
151 }
152
153 pub fn metadata(&self) -> AppMetadata {
154 self.0.borrow().app_metadata.clone()
155 }
156
157 pub fn background_executor(&self) -> BackgroundExecutor {
158 self.0.borrow().background_executor.clone()
159 }
160
161 pub fn foreground_executor(&self) -> ForegroundExecutor {
162 self.0.borrow().foreground_executor.clone()
163 }
164
165 pub fn text_system(&self) -> Arc<TextSystem> {
166 self.0.borrow().text_system.clone()
167 }
168}
169
170pub(crate) type FrameCallback = Box<dyn FnOnce(&mut AppContext)>;
171type Handler = Box<dyn FnMut(&mut AppContext) -> bool + 'static>;
172type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + 'static>;
173type QuitHandler = Box<dyn FnOnce(&mut AppContext) -> LocalBoxFuture<'static, ()> + 'static>;
174type ReleaseListener = Box<dyn FnOnce(&mut dyn Any, &mut AppContext) + 'static>;
175type NewViewListener = Box<dyn FnMut(AnyView, &mut WindowContext) + 'static>;
176
177// struct FrameConsumer {
178// next_frame_callbacks: Vec<FrameCallback>,
179// task: Task<()>,
180// display_linker
181// }
182
183pub struct AppContext {
184 pub(crate) this: Weak<AppCell>,
185 pub(crate) platform: Rc<dyn Platform>,
186 app_metadata: AppMetadata,
187 text_system: Arc<TextSystem>,
188 flushing_effects: bool,
189 pending_updates: usize,
190 pub(crate) actions: Rc<ActionRegistry>,
191 pub(crate) active_drag: Option<AnyDrag>,
192 pub(crate) active_tooltip: Option<AnyTooltip>,
193 pub(crate) next_frame_callbacks: HashMap<DisplayId, Vec<FrameCallback>>,
194 pub(crate) frame_consumers: HashMap<DisplayId, Task<()>>,
195 pub(crate) background_executor: BackgroundExecutor,
196 pub(crate) foreground_executor: ForegroundExecutor,
197 pub(crate) svg_renderer: SvgRenderer,
198 asset_source: Arc<dyn AssetSource>,
199 pub(crate) image_cache: ImageCache,
200 pub(crate) text_style_stack: Vec<TextStyleRefinement>,
201 pub(crate) globals_by_type: HashMap<TypeId, Box<dyn Any>>,
202 pub(crate) entities: EntityMap,
203 pub(crate) new_view_observers: SubscriberSet<TypeId, NewViewListener>,
204 pub(crate) windows: SlotMap<WindowId, Option<Window>>,
205 pub(crate) keymap: Arc<Mutex<Keymap>>,
206 pub(crate) global_action_listeners:
207 HashMap<TypeId, Vec<Rc<dyn Fn(&dyn Any, DispatchPhase, &mut Self)>>>,
208 pending_effects: VecDeque<Effect>,
209 pub(crate) pending_notifications: HashSet<EntityId>,
210 pub(crate) pending_global_notifications: HashSet<TypeId>,
211 pub(crate) observers: SubscriberSet<EntityId, Handler>,
212 // TypeId is the type of the event that the listener callback expects
213 pub(crate) event_listeners: SubscriberSet<EntityId, (TypeId, Listener)>,
214 pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
215 pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
216 pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
217 pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
218 pub(crate) propagate_event: bool,
219}
220
221impl AppContext {
222 pub(crate) fn new(
223 platform: Rc<dyn Platform>,
224 asset_source: Arc<dyn AssetSource>,
225 http_client: Arc<dyn HttpClient>,
226 ) -> Rc<AppCell> {
227 let executor = platform.background_executor();
228 let foreground_executor = platform.foreground_executor();
229 assert!(
230 executor.is_main_thread(),
231 "must construct App on main thread"
232 );
233
234 let text_system = Arc::new(TextSystem::new(platform.text_system()));
235 let entities = EntityMap::new();
236
237 let app_metadata = AppMetadata {
238 os_name: platform.os_name(),
239 os_version: platform.os_version().ok(),
240 app_version: platform.app_version().ok(),
241 };
242
243 let app = Rc::new_cyclic(|this| AppCell {
244 app: RefCell::new(AppContext {
245 this: this.clone(),
246 platform: platform.clone(),
247 app_metadata,
248 text_system,
249 actions: Rc::new(ActionRegistry::default()),
250 flushing_effects: false,
251 pending_updates: 0,
252 active_drag: None,
253 active_tooltip: None,
254 next_frame_callbacks: HashMap::default(),
255 frame_consumers: HashMap::default(),
256 background_executor: executor,
257 foreground_executor,
258 svg_renderer: SvgRenderer::new(asset_source.clone()),
259 asset_source,
260 image_cache: ImageCache::new(http_client),
261 text_style_stack: Vec::new(),
262 globals_by_type: HashMap::default(),
263 entities,
264 new_view_observers: SubscriberSet::new(),
265 windows: SlotMap::with_key(),
266 keymap: Arc::new(Mutex::new(Keymap::default())),
267 global_action_listeners: HashMap::default(),
268 pending_effects: VecDeque::new(),
269 pending_notifications: HashSet::default(),
270 pending_global_notifications: HashSet::default(),
271 observers: SubscriberSet::new(),
272 event_listeners: SubscriberSet::new(),
273 release_listeners: SubscriberSet::new(),
274 global_observers: SubscriberSet::new(),
275 quit_observers: SubscriberSet::new(),
276 layout_id_buffer: Default::default(),
277 propagate_event: true,
278 }),
279 });
280
281 init_app_menus(platform.as_ref(), &mut *app.borrow_mut());
282
283 platform.on_quit(Box::new({
284 let cx = app.clone();
285 move || {
286 cx.borrow_mut().shutdown();
287 }
288 }));
289
290 app
291 }
292
293 /// Quit the application gracefully. Handlers registered with `ModelContext::on_app_quit`
294 /// will be given 100ms to complete before exiting.
295 pub fn shutdown(&mut self) {
296 let mut futures = Vec::new();
297
298 for observer in self.quit_observers.remove(&()) {
299 futures.push(observer(self));
300 }
301
302 self.windows.clear();
303 self.flush_effects();
304
305 let futures = futures::future::join_all(futures);
306 if self
307 .background_executor
308 .block_with_timeout(Duration::from_millis(100), futures)
309 .is_err()
310 {
311 log::error!("timed out waiting on app_will_quit");
312 }
313 }
314
315 pub fn quit(&mut self) {
316 self.platform.quit();
317 }
318
319 pub fn app_metadata(&self) -> AppMetadata {
320 self.app_metadata.clone()
321 }
322
323 /// Schedules all windows in the application to be redrawn. This can be called
324 /// multiple times in an update cycle and still result in a single redraw.
325 pub fn refresh(&mut self) {
326 self.pending_effects.push_back(Effect::Refresh);
327 }
328 pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
329 self.pending_updates += 1;
330 let result = update(self);
331 if !self.flushing_effects && self.pending_updates == 1 {
332 self.flushing_effects = true;
333 self.flush_effects();
334 self.flushing_effects = false;
335 }
336 self.pending_updates -= 1;
337 result
338 }
339
340 pub fn observe<W, E>(
341 &mut self,
342 entity: &E,
343 mut on_notify: impl FnMut(E, &mut AppContext) + 'static,
344 ) -> Subscription
345 where
346 W: 'static,
347 E: Entity<W>,
348 {
349 self.observe_internal(entity, move |e, cx| {
350 on_notify(e, cx);
351 true
352 })
353 }
354
355 pub fn observe_internal<W, E>(
356 &mut self,
357 entity: &E,
358 mut on_notify: impl FnMut(E, &mut AppContext) -> bool + 'static,
359 ) -> Subscription
360 where
361 W: 'static,
362 E: Entity<W>,
363 {
364 let entity_id = entity.entity_id();
365 let handle = entity.downgrade();
366 let (subscription, activate) = self.observers.insert(
367 entity_id,
368 Box::new(move |cx| {
369 if let Some(handle) = E::upgrade_from(&handle) {
370 on_notify(handle, cx)
371 } else {
372 false
373 }
374 }),
375 );
376 self.defer(move |_| activate());
377 subscription
378 }
379
380 pub fn subscribe<T, E, Evt>(
381 &mut self,
382 entity: &E,
383 mut on_event: impl FnMut(E, &Evt, &mut AppContext) + 'static,
384 ) -> Subscription
385 where
386 T: 'static + EventEmitter<Evt>,
387 E: Entity<T>,
388 Evt: 'static,
389 {
390 self.subscribe_internal(entity, move |entity, event, cx| {
391 on_event(entity, event, cx);
392 true
393 })
394 }
395
396 pub(crate) fn subscribe_internal<T, E, Evt>(
397 &mut self,
398 entity: &E,
399 mut on_event: impl FnMut(E, &Evt, &mut AppContext) -> bool + 'static,
400 ) -> Subscription
401 where
402 T: 'static + EventEmitter<Evt>,
403 E: Entity<T>,
404 Evt: 'static,
405 {
406 let entity_id = entity.entity_id();
407 let entity = entity.downgrade();
408 let (subscription, activate) = self.event_listeners.insert(
409 entity_id,
410 (
411 TypeId::of::<Evt>(),
412 Box::new(move |event, cx| {
413 let event: &Evt = event.downcast_ref().expect("invalid event type");
414 if let Some(handle) = E::upgrade_from(&entity) {
415 on_event(handle, event, cx)
416 } else {
417 false
418 }
419 }),
420 ),
421 );
422 self.defer(move |_| activate());
423 subscription
424 }
425
426 pub fn windows(&self) -> Vec<AnyWindowHandle> {
427 self.windows
428 .values()
429 .filter_map(|window| Some(window.as_ref()?.handle.clone()))
430 .collect()
431 }
432
433 pub fn active_window(&self) -> Option<AnyWindowHandle> {
434 self.platform.active_window()
435 }
436
437 /// Opens a new window with the given option and the root view returned by the given function.
438 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
439 /// functionality.
440 pub fn open_window<V: 'static + Render>(
441 &mut self,
442 options: crate::WindowOptions,
443 build_root_view: impl FnOnce(&mut WindowContext) -> View<V>,
444 ) -> WindowHandle<V> {
445 self.update(|cx| {
446 let id = cx.windows.insert(None);
447 let handle = WindowHandle::new(id);
448 let mut window = Window::new(handle.into(), options, cx);
449 let root_view = build_root_view(&mut WindowContext::new(cx, &mut window));
450 window.root_view.replace(root_view.into());
451 cx.windows.get_mut(id).unwrap().replace(window);
452 handle
453 })
454 }
455
456 /// Instructs the platform to activate the application by bringing it to the foreground.
457 pub fn activate(&self, ignoring_other_apps: bool) {
458 self.platform.activate(ignoring_other_apps);
459 }
460
461 pub fn hide(&self) {
462 self.platform.hide();
463 }
464
465 pub fn hide_other_apps(&self) {
466 self.platform.hide_other_apps();
467 }
468
469 pub fn unhide_other_apps(&self) {
470 self.platform.unhide_other_apps();
471 }
472
473 /// Returns the list of currently active displays.
474 pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
475 self.platform.displays()
476 }
477
478 /// Writes data to the platform clipboard.
479 pub fn write_to_clipboard(&self, item: ClipboardItem) {
480 self.platform.write_to_clipboard(item)
481 }
482
483 /// Reads data from the platform clipboard.
484 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
485 self.platform.read_from_clipboard()
486 }
487
488 /// Writes credentials to the platform keychain.
489 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
490 self.platform.write_credentials(url, username, password)
491 }
492
493 /// Reads credentials from the platform keychain.
494 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
495 self.platform.read_credentials(url)
496 }
497
498 /// Deletes credentials from the platform keychain.
499 pub fn delete_credentials(&self, url: &str) -> Result<()> {
500 self.platform.delete_credentials(url)
501 }
502
503 /// Directs the platform's default browser to open the given URL.
504 pub fn open_url(&self, url: &str) {
505 self.platform.open_url(url);
506 }
507
508 pub fn app_path(&self) -> Result<PathBuf> {
509 self.platform.app_path()
510 }
511
512 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
513 self.platform.path_for_auxiliary_executable(name)
514 }
515
516 pub fn prompt_for_paths(
517 &self,
518 options: PathPromptOptions,
519 ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
520 self.platform.prompt_for_paths(options)
521 }
522
523 pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
524 self.platform.prompt_for_new_path(directory)
525 }
526
527 pub fn reveal_path(&self, path: &Path) {
528 self.platform.reveal_path(path)
529 }
530
531 pub fn should_auto_hide_scrollbars(&self) -> bool {
532 self.platform.should_auto_hide_scrollbars()
533 }
534
535 pub fn restart(&self) {
536 self.platform.restart()
537 }
538
539 pub(crate) fn push_effect(&mut self, effect: Effect) {
540 match &effect {
541 Effect::Notify { emitter } => {
542 if !self.pending_notifications.insert(*emitter) {
543 return;
544 }
545 }
546 Effect::NotifyGlobalObservers { global_type } => {
547 if !self.pending_global_notifications.insert(*global_type) {
548 return;
549 }
550 }
551 _ => {}
552 };
553
554 self.pending_effects.push_back(effect);
555 }
556
557 /// Called at the end of AppContext::update to complete any side effects
558 /// such as notifying observers, emitting events, etc. Effects can themselves
559 /// cause effects, so we continue looping until all effects are processed.
560 fn flush_effects(&mut self) {
561 loop {
562 self.release_dropped_entities();
563 self.release_dropped_focus_handles();
564 if let Some(effect) = self.pending_effects.pop_front() {
565 match effect {
566 Effect::Notify { emitter } => {
567 self.apply_notify_effect(emitter);
568 }
569 Effect::Emit {
570 emitter,
571 event_type,
572 event,
573 } => self.apply_emit_effect(emitter, event_type, event),
574 Effect::FocusChanged {
575 window_handle,
576 focused,
577 } => {
578 self.apply_focus_changed_effect(window_handle, focused);
579 }
580 Effect::Refresh => {
581 self.apply_refresh_effect();
582 }
583 Effect::NotifyGlobalObservers { global_type } => {
584 self.apply_notify_global_observers_effect(global_type);
585 }
586 Effect::Defer { callback } => {
587 self.apply_defer_effect(callback);
588 }
589 }
590 } else {
591 break;
592 }
593 }
594
595 let dirty_window_ids = self
596 .windows
597 .iter()
598 .filter_map(|(_, window)| {
599 let window = window.as_ref()?;
600 if window.dirty {
601 Some(window.handle.clone())
602 } else {
603 None
604 }
605 })
606 .collect::<SmallVec<[_; 8]>>();
607
608 for dirty_window_handle in dirty_window_ids {
609 dirty_window_handle.update(self, |_, cx| cx.draw()).unwrap();
610 }
611 }
612
613 /// Repeatedly called during `flush_effects` to release any entities whose
614 /// reference count has become zero. We invoke any release observers before dropping
615 /// each entity.
616 fn release_dropped_entities(&mut self) {
617 loop {
618 let dropped = self.entities.take_dropped();
619 if dropped.is_empty() {
620 break;
621 }
622
623 for (entity_id, mut entity) in dropped {
624 self.observers.remove(&entity_id);
625 self.event_listeners.remove(&entity_id);
626 for release_callback in self.release_listeners.remove(&entity_id) {
627 release_callback(entity.as_mut(), self);
628 }
629 }
630 }
631 }
632
633 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
634 /// For now, we simply blur the window if this happens, but we may want to support invoking
635 /// a window blur handler to restore focus to some logical element.
636 fn release_dropped_focus_handles(&mut self) {
637 for window_handle in self.windows() {
638 window_handle
639 .update(self, |_, cx| {
640 let mut blur_window = false;
641 let focus = cx.window.focus;
642 cx.window.focus_handles.write().retain(|handle_id, count| {
643 if count.load(SeqCst) == 0 {
644 if focus == Some(handle_id) {
645 blur_window = true;
646 }
647 false
648 } else {
649 true
650 }
651 });
652
653 if blur_window {
654 cx.blur();
655 }
656 })
657 .unwrap();
658 }
659 }
660
661 fn apply_notify_effect(&mut self, emitter: EntityId) {
662 self.pending_notifications.remove(&emitter);
663
664 self.observers
665 .clone()
666 .retain(&emitter, |handler| handler(self));
667 }
668
669 fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: Box<dyn Any>) {
670 self.event_listeners
671 .clone()
672 .retain(&emitter, |(stored_type, handler)| {
673 if *stored_type == event_type {
674 handler(event.as_ref(), self)
675 } else {
676 true
677 }
678 });
679 }
680
681 fn apply_focus_changed_effect(
682 &mut self,
683 window_handle: AnyWindowHandle,
684 focused: Option<FocusId>,
685 ) {
686 window_handle
687 .update(self, |_, cx| {
688 // The window might change focus multiple times in an effect cycle.
689 // We only honor effects for the most recently focused handle.
690 if cx.window.focus == focused {
691 // if someone calls focus multiple times in one frame with the same handle
692 // the first apply_focus_changed_effect will have taken the last blur already
693 // and run the rest of this, so we can return.
694 let Some(last_blur) = cx.window.last_blur.take() else {
695 return;
696 };
697
698 let focused = focused
699 .map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
700
701 let blurred =
702 last_blur.and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
703
704 let focus_changed = focused.is_some() || blurred.is_some();
705 let event = FocusEvent { focused, blurred };
706
707 let mut listeners = mem::take(&mut cx.window.current_frame.focus_listeners);
708 if focus_changed {
709 for listener in &mut listeners {
710 listener(&event, cx);
711 }
712 }
713 listeners.extend(cx.window.current_frame.focus_listeners.drain(..));
714 cx.window.current_frame.focus_listeners = listeners;
715
716 if focus_changed {
717 cx.window
718 .focus_listeners
719 .clone()
720 .retain(&(), |listener| listener(&event, cx));
721 }
722 }
723 })
724 .ok();
725 }
726
727 fn apply_refresh_effect(&mut self) {
728 for window in self.windows.values_mut() {
729 if let Some(window) = window.as_mut() {
730 window.dirty = true;
731 }
732 }
733 }
734
735 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
736 self.pending_global_notifications.remove(&type_id);
737 self.global_observers
738 .clone()
739 .retain(&type_id, |observer| observer(self));
740 }
741
742 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
743 callback(self);
744 }
745
746 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
747 /// so it can be held across `await` points.
748 pub fn to_async(&self) -> AsyncAppContext {
749 AsyncAppContext {
750 app: unsafe { mem::transmute(self.this.clone()) },
751 background_executor: self.background_executor.clone(),
752 foreground_executor: self.foreground_executor.clone(),
753 }
754 }
755
756 /// Obtains a reference to the executor, which can be used to spawn futures.
757 pub fn background_executor(&self) -> &BackgroundExecutor {
758 &self.background_executor
759 }
760
761 /// Obtains a reference to the executor, which can be used to spawn futures.
762 pub fn foreground_executor(&self) -> &ForegroundExecutor {
763 &self.foreground_executor
764 }
765
766 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
767 /// with AsyncAppContext, which allows the application state to be accessed across await points.
768 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
769 where
770 Fut: Future<Output = R> + 'static,
771 R: 'static,
772 {
773 self.foreground_executor.spawn(f(self.to_async()))
774 }
775
776 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
777 /// that are currently on the stack to be returned to the app.
778 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
779 self.push_effect(Effect::Defer {
780 callback: Box::new(f),
781 });
782 }
783
784 /// Accessor for the application's asset source, which is provided when constructing the `App`.
785 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
786 &self.asset_source
787 }
788
789 /// Accessor for the text system.
790 pub fn text_system(&self) -> &Arc<TextSystem> {
791 &self.text_system
792 }
793
794 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
795 pub fn text_style(&self) -> TextStyle {
796 let mut style = TextStyle::default();
797 for refinement in &self.text_style_stack {
798 style.refine(refinement);
799 }
800 style
801 }
802
803 /// Check whether a global of the given type has been assigned.
804 pub fn has_global<G: 'static>(&self) -> bool {
805 self.globals_by_type.contains_key(&TypeId::of::<G>())
806 }
807
808 /// Access the global of the given type. Panics if a global for that type has not been assigned.
809 #[track_caller]
810 pub fn global<G: 'static>(&self) -> &G {
811 self.globals_by_type
812 .get(&TypeId::of::<G>())
813 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
814 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
815 .unwrap()
816 }
817
818 /// Access the global of the given type if a value has been assigned.
819 pub fn try_global<G: 'static>(&self) -> Option<&G> {
820 self.globals_by_type
821 .get(&TypeId::of::<G>())
822 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
823 }
824
825 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
826 #[track_caller]
827 pub fn global_mut<G: 'static>(&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 .get_mut(&global_type)
832 .and_then(|any_state| any_state.downcast_mut::<G>())
833 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
834 .unwrap()
835 }
836
837 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
838 /// yet been assigned.
839 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
840 let global_type = TypeId::of::<G>();
841 self.push_effect(Effect::NotifyGlobalObservers { global_type });
842 self.globals_by_type
843 .entry(global_type)
844 .or_insert_with(|| Box::new(G::default()))
845 .downcast_mut::<G>()
846 .unwrap()
847 }
848
849 /// Set the value of the global of the given type.
850 pub fn set_global<G: Any>(&mut self, global: G) {
851 let global_type = TypeId::of::<G>();
852 self.push_effect(Effect::NotifyGlobalObservers { global_type });
853 self.globals_by_type.insert(global_type, Box::new(global));
854 }
855
856 /// Clear all stored globals. Does not notify global observers.
857 #[cfg(any(test, feature = "test-support"))]
858 pub fn clear_globals(&mut self) {
859 self.globals_by_type.drain();
860 }
861
862 /// Remove the global of the given type from the app context. Does not notify global observers.
863 #[cfg(any(test, feature = "test-support"))]
864 pub fn remove_global<G: Any>(&mut self) -> G {
865 let global_type = TypeId::of::<G>();
866 *self
867 .globals_by_type
868 .remove(&global_type)
869 .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
870 .downcast()
871 .unwrap()
872 }
873
874 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
875 /// your closure with mutable access to the `AppContext` and the global simultaneously.
876 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
877 let mut global = self.lease_global::<G>();
878 let result = f(&mut global, self);
879 self.end_global_lease(global);
880 result
881 }
882
883 /// Register a callback to be invoked when a global of the given type is updated.
884 pub fn observe_global<G: 'static>(
885 &mut self,
886 mut f: impl FnMut(&mut Self) + 'static,
887 ) -> Subscription {
888 let (subscription, activate) = self.global_observers.insert(
889 TypeId::of::<G>(),
890 Box::new(move |cx| {
891 f(cx);
892 true
893 }),
894 );
895 self.defer(move |_| activate());
896 subscription
897 }
898
899 /// Move the global of the given type to the stack.
900 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
901 GlobalLease::new(
902 self.globals_by_type
903 .remove(&TypeId::of::<G>())
904 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
905 .unwrap(),
906 )
907 }
908
909 /// Restore the global of the given type after it is moved to the stack.
910 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
911 let global_type = TypeId::of::<G>();
912 self.push_effect(Effect::NotifyGlobalObservers { global_type });
913 self.globals_by_type.insert(global_type, lease.global);
914 }
915
916 pub fn observe_new_views<V: 'static>(
917 &mut self,
918 on_new: impl 'static + Fn(&mut V, &mut ViewContext<V>),
919 ) -> Subscription {
920 let (subscription, activate) = self.new_view_observers.insert(
921 TypeId::of::<V>(),
922 Box::new(move |any_view: AnyView, cx: &mut WindowContext| {
923 any_view
924 .downcast::<V>()
925 .unwrap()
926 .update(cx, |view_state, cx| {
927 on_new(view_state, cx);
928 })
929 }),
930 );
931 activate();
932 subscription
933 }
934
935 pub fn observe_release<E, T>(
936 &mut self,
937 handle: &E,
938 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
939 ) -> Subscription
940 where
941 E: Entity<T>,
942 T: 'static,
943 {
944 let (subscription, activate) = self.release_listeners.insert(
945 handle.entity_id(),
946 Box::new(move |entity, cx| {
947 let entity = entity.downcast_mut().expect("invalid entity type");
948 on_release(entity, cx)
949 }),
950 );
951 activate();
952 subscription
953 }
954
955 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
956 self.text_style_stack.push(text_style);
957 }
958
959 pub(crate) fn pop_text_style(&mut self) {
960 self.text_style_stack.pop();
961 }
962
963 /// Register key bindings.
964 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
965 self.keymap.lock().add_bindings(bindings);
966 self.pending_effects.push_back(Effect::Refresh);
967 }
968
969 /// Register a global listener for actions invoked via the keyboard.
970 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
971 self.global_action_listeners
972 .entry(TypeId::of::<A>())
973 .or_default()
974 .push(Rc::new(move |action, phase, cx| {
975 if phase == DispatchPhase::Bubble {
976 let action = action.downcast_ref().unwrap();
977 listener(action, cx)
978 }
979 }));
980 }
981
982 /// Event handlers propagate events by default. Call this method to stop dispatching to
983 /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
984 /// the opposite of [propagate]. It's also possible to cancel a call to [propagate] by
985 /// calling this method before effects are flushed.
986 pub fn stop_propagation(&mut self) {
987 self.propagate_event = false;
988 }
989
990 /// Action handlers stop propagation by default during the bubble phase of action dispatch
991 /// dispatching to action handlers higher in the element tree. This is the opposite of
992 /// [stop_propagation]. It's also possible to cancel a call to [stop_propagate] by calling
993 /// this method before effects are flushed.
994 pub fn propagate(&mut self) {
995 self.propagate_event = true;
996 }
997
998 pub fn build_action(
999 &self,
1000 name: &str,
1001 data: Option<serde_json::Value>,
1002 ) -> Result<Box<dyn Action>> {
1003 self.actions.build_action(name, data)
1004 }
1005
1006 pub fn all_action_names(&self) -> &[SharedString] {
1007 self.actions.all_action_names()
1008 }
1009
1010 pub fn on_app_quit<Fut>(
1011 &mut self,
1012 mut on_quit: impl FnMut(&mut AppContext) -> Fut + 'static,
1013 ) -> Subscription
1014 where
1015 Fut: 'static + Future<Output = ()>,
1016 {
1017 let (subscription, activate) = self.quit_observers.insert(
1018 (),
1019 Box::new(move |cx| {
1020 let future = on_quit(cx);
1021 async move { future.await }.boxed_local()
1022 }),
1023 );
1024 activate();
1025 subscription
1026 }
1027
1028 pub(crate) fn clear_pending_keystrokes(&mut self) {
1029 for window in self.windows() {
1030 window
1031 .update(self, |_, cx| {
1032 cx.window
1033 .current_frame
1034 .dispatch_tree
1035 .clear_pending_keystrokes()
1036 })
1037 .ok();
1038 }
1039 }
1040
1041 pub fn is_action_available(&mut self, action: &dyn Action) -> bool {
1042 if let Some(window) = self.active_window() {
1043 if let Ok(window_action_available) =
1044 window.update(self, |_, cx| cx.is_action_available(action))
1045 {
1046 return window_action_available;
1047 }
1048 }
1049
1050 self.global_action_listeners
1051 .contains_key(&action.as_any().type_id())
1052 }
1053
1054 pub fn set_menus(&mut self, menus: Vec<Menu>) {
1055 self.platform.set_menus(menus, &self.keymap.lock());
1056 }
1057
1058 pub fn dispatch_action(&mut self, action: &dyn Action) {
1059 if let Some(active_window) = self.active_window() {
1060 active_window
1061 .update(self, |_, cx| cx.dispatch_action(action.boxed_clone()))
1062 .log_err();
1063 } else {
1064 self.propagate_event = true;
1065
1066 if let Some(mut global_listeners) = self
1067 .global_action_listeners
1068 .remove(&action.as_any().type_id())
1069 {
1070 for listener in &global_listeners {
1071 listener(action.as_any(), DispatchPhase::Capture, self);
1072 if !self.propagate_event {
1073 break;
1074 }
1075 }
1076
1077 global_listeners.extend(
1078 self.global_action_listeners
1079 .remove(&action.as_any().type_id())
1080 .unwrap_or_default(),
1081 );
1082
1083 self.global_action_listeners
1084 .insert(action.as_any().type_id(), global_listeners);
1085 }
1086
1087 if self.propagate_event {
1088 if let Some(mut global_listeners) = self
1089 .global_action_listeners
1090 .remove(&action.as_any().type_id())
1091 {
1092 for listener in global_listeners.iter().rev() {
1093 listener(action.as_any(), DispatchPhase::Bubble, self);
1094 if !self.propagate_event {
1095 break;
1096 }
1097 }
1098
1099 global_listeners.extend(
1100 self.global_action_listeners
1101 .remove(&action.as_any().type_id())
1102 .unwrap_or_default(),
1103 );
1104
1105 self.global_action_listeners
1106 .insert(action.as_any().type_id(), global_listeners);
1107 }
1108 }
1109 }
1110 }
1111}
1112
1113impl Context for AppContext {
1114 type Result<T> = T;
1115
1116 /// Build an entity that is owned by the application. The given function will be invoked with
1117 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
1118 /// which can be used to access the entity in a context.
1119 fn build_model<T: 'static>(
1120 &mut self,
1121 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1122 ) -> Model<T> {
1123 self.update(|cx| {
1124 let slot = cx.entities.reserve();
1125 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
1126 cx.entities.insert(slot, entity)
1127 })
1128 }
1129
1130 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
1131 /// entity along with a `ModelContext` for the entity.
1132 fn update_model<T: 'static, R>(
1133 &mut self,
1134 model: &Model<T>,
1135 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1136 ) -> R {
1137 self.update(|cx| {
1138 let mut entity = cx.entities.lease(model);
1139 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
1140 cx.entities.end_lease(entity);
1141 result
1142 })
1143 }
1144
1145 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
1146 where
1147 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1148 {
1149 self.update(|cx| {
1150 let mut window = cx
1151 .windows
1152 .get_mut(handle.id)
1153 .ok_or_else(|| anyhow!("window not found"))?
1154 .take()
1155 .unwrap();
1156
1157 let root_view = window.root_view.clone().unwrap();
1158 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
1159
1160 if window.removed {
1161 cx.windows.remove(handle.id);
1162 } else {
1163 cx.windows
1164 .get_mut(handle.id)
1165 .ok_or_else(|| anyhow!("window not found"))?
1166 .replace(window);
1167 }
1168
1169 Ok(result)
1170 })
1171 }
1172
1173 fn read_model<T, R>(
1174 &self,
1175 handle: &Model<T>,
1176 read: impl FnOnce(&T, &AppContext) -> R,
1177 ) -> Self::Result<R>
1178 where
1179 T: 'static,
1180 {
1181 let entity = self.entities.read(handle);
1182 read(entity, self)
1183 }
1184
1185 fn read_window<T, R>(
1186 &self,
1187 window: &WindowHandle<T>,
1188 read: impl FnOnce(View<T>, &AppContext) -> R,
1189 ) -> Result<R>
1190 where
1191 T: 'static,
1192 {
1193 let window = self
1194 .windows
1195 .get(window.id)
1196 .ok_or_else(|| anyhow!("window not found"))?
1197 .as_ref()
1198 .unwrap();
1199
1200 let root_view = window.root_view.clone().unwrap();
1201 let view = root_view
1202 .downcast::<T>()
1203 .map_err(|_| anyhow!("root view's type has changed"))?;
1204
1205 Ok(read(view, self))
1206 }
1207}
1208
1209/// These effects are processed at the end of each application update cycle.
1210pub(crate) enum Effect {
1211 Notify {
1212 emitter: EntityId,
1213 },
1214 Emit {
1215 emitter: EntityId,
1216 event_type: TypeId,
1217 event: Box<dyn Any>,
1218 },
1219 FocusChanged {
1220 window_handle: AnyWindowHandle,
1221 focused: Option<FocusId>,
1222 },
1223 Refresh,
1224 NotifyGlobalObservers {
1225 global_type: TypeId,
1226 },
1227 Defer {
1228 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
1229 },
1230}
1231
1232/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
1233pub(crate) struct GlobalLease<G: 'static> {
1234 global: Box<dyn Any>,
1235 global_type: PhantomData<G>,
1236}
1237
1238impl<G: 'static> GlobalLease<G> {
1239 fn new(global: Box<dyn Any>) -> Self {
1240 GlobalLease {
1241 global,
1242 global_type: PhantomData,
1243 }
1244 }
1245}
1246
1247impl<G: 'static> Deref for GlobalLease<G> {
1248 type Target = G;
1249
1250 fn deref(&self) -> &Self::Target {
1251 self.global.downcast_ref().unwrap()
1252 }
1253}
1254
1255impl<G: 'static> DerefMut for GlobalLease<G> {
1256 fn deref_mut(&mut self) -> &mut Self::Target {
1257 self.global.downcast_mut().unwrap()
1258 }
1259}
1260
1261/// Contains state associated with an active drag operation, started by dragging an element
1262/// within the window or by dragging into the app from the underlying platform.
1263pub struct AnyDrag {
1264 pub view: AnyView,
1265 pub cursor_offset: Point<Pixels>,
1266}
1267
1268#[derive(Clone)]
1269pub(crate) struct AnyTooltip {
1270 pub view: AnyView,
1271 pub cursor_offset: Point<Pixels>,
1272}