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 smol::future::FutureExt;
13#[cfg(any(test, feature = "test-support"))]
14pub use test_context::*;
15use time::UtcOffset;
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 double_click_interval(&self) -> Duration {
517 self.platform.double_click_interval()
518 }
519
520 pub fn prompt_for_paths(
521 &self,
522 options: PathPromptOptions,
523 ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
524 self.platform.prompt_for_paths(options)
525 }
526
527 pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
528 self.platform.prompt_for_new_path(directory)
529 }
530
531 pub fn reveal_path(&self, path: &Path) {
532 self.platform.reveal_path(path)
533 }
534
535 pub fn should_auto_hide_scrollbars(&self) -> bool {
536 self.platform.should_auto_hide_scrollbars()
537 }
538
539 pub fn restart(&self) {
540 self.platform.restart()
541 }
542
543 pub fn local_timezone(&self) -> UtcOffset {
544 self.platform.local_timezone()
545 }
546
547 pub(crate) fn push_effect(&mut self, effect: Effect) {
548 match &effect {
549 Effect::Notify { emitter } => {
550 if !self.pending_notifications.insert(*emitter) {
551 return;
552 }
553 }
554 Effect::NotifyGlobalObservers { global_type } => {
555 if !self.pending_global_notifications.insert(*global_type) {
556 return;
557 }
558 }
559 _ => {}
560 };
561
562 self.pending_effects.push_back(effect);
563 }
564
565 /// Called at the end of AppContext::update to complete any side effects
566 /// such as notifying observers, emitting events, etc. Effects can themselves
567 /// cause effects, so we continue looping until all effects are processed.
568 fn flush_effects(&mut self) {
569 loop {
570 self.release_dropped_entities();
571 self.release_dropped_focus_handles();
572 if let Some(effect) = self.pending_effects.pop_front() {
573 match effect {
574 Effect::Notify { emitter } => {
575 self.apply_notify_effect(emitter);
576 }
577 Effect::Emit {
578 emitter,
579 event_type,
580 event,
581 } => self.apply_emit_effect(emitter, event_type, event),
582 Effect::FocusChanged {
583 window_handle,
584 focused,
585 } => {
586 self.apply_focus_changed_effect(window_handle, focused);
587 }
588 Effect::Refresh => {
589 self.apply_refresh_effect();
590 }
591 Effect::NotifyGlobalObservers { global_type } => {
592 self.apply_notify_global_observers_effect(global_type);
593 }
594 Effect::Defer { callback } => {
595 self.apply_defer_effect(callback);
596 }
597 }
598 } else {
599 break;
600 }
601 }
602
603 for window in self.windows.values() {
604 if let Some(window) = window.as_ref() {
605 if window.dirty {
606 window.platform_window.invalidate();
607 }
608 }
609 }
610
611 #[cfg(any(test, feature = "test-support"))]
612 for window in self
613 .windows
614 .values()
615 .filter_map(|window| {
616 let window = window.as_ref()?;
617 window.dirty.then_some(window.handle)
618 })
619 .collect::<Vec<_>>()
620 {
621 self.update_window(window, |_, cx| cx.draw()).unwrap();
622 }
623 }
624
625 /// Repeatedly called during `flush_effects` to release any entities whose
626 /// reference count has become zero. We invoke any release observers before dropping
627 /// each entity.
628 fn release_dropped_entities(&mut self) {
629 loop {
630 let dropped = self.entities.take_dropped();
631 if dropped.is_empty() {
632 break;
633 }
634
635 for (entity_id, mut entity) in dropped {
636 self.observers.remove(&entity_id);
637 self.event_listeners.remove(&entity_id);
638 for release_callback in self.release_listeners.remove(&entity_id) {
639 release_callback(entity.as_mut(), self);
640 }
641 }
642 }
643 }
644
645 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
646 /// For now, we simply blur the window if this happens, but we may want to support invoking
647 /// a window blur handler to restore focus to some logical element.
648 fn release_dropped_focus_handles(&mut self) {
649 for window_handle in self.windows() {
650 window_handle
651 .update(self, |_, cx| {
652 let mut blur_window = false;
653 let focus = cx.window.focus;
654 cx.window.focus_handles.write().retain(|handle_id, count| {
655 if count.load(SeqCst) == 0 {
656 if focus == Some(handle_id) {
657 blur_window = true;
658 }
659 false
660 } else {
661 true
662 }
663 });
664
665 if blur_window {
666 cx.blur();
667 }
668 })
669 .unwrap();
670 }
671 }
672
673 fn apply_notify_effect(&mut self, emitter: EntityId) {
674 self.pending_notifications.remove(&emitter);
675
676 self.observers
677 .clone()
678 .retain(&emitter, |handler| handler(self));
679 }
680
681 fn apply_emit_effect(&mut self, emitter: EntityId, event_type: TypeId, event: Box<dyn Any>) {
682 self.event_listeners
683 .clone()
684 .retain(&emitter, |(stored_type, handler)| {
685 if *stored_type == event_type {
686 handler(event.as_ref(), self)
687 } else {
688 true
689 }
690 });
691 }
692
693 fn apply_focus_changed_effect(
694 &mut self,
695 window_handle: AnyWindowHandle,
696 focused: Option<FocusId>,
697 ) {
698 window_handle
699 .update(self, |_, cx| {
700 // The window might change focus multiple times in an effect cycle.
701 // We only honor effects for the most recently focused handle.
702 if cx.window.focus == focused {
703 // if someone calls focus multiple times in one frame with the same handle
704 // the first apply_focus_changed_effect will have taken the last blur already
705 // and run the rest of this, so we can return.
706 let Some(last_blur) = cx.window.last_blur.take() else {
707 return;
708 };
709
710 let focused = focused
711 .map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
712
713 let blurred =
714 last_blur.and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
715
716 let focus_changed = focused.is_some() || blurred.is_some();
717 let event = FocusEvent { focused, blurred };
718
719 let mut listeners = mem::take(&mut cx.window.rendered_frame.focus_listeners);
720 if focus_changed {
721 for listener in &mut listeners {
722 listener(&event, cx);
723 }
724 }
725 cx.window.rendered_frame.focus_listeners = listeners;
726
727 if focus_changed {
728 cx.window
729 .focus_listeners
730 .clone()
731 .retain(&(), |listener| listener(&event, cx));
732 }
733 }
734 })
735 .ok();
736 }
737
738 fn apply_refresh_effect(&mut self) {
739 for window in self.windows.values_mut() {
740 if let Some(window) = window.as_mut() {
741 window.dirty = true;
742 }
743 }
744 }
745
746 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
747 self.pending_global_notifications.remove(&type_id);
748 self.global_observers
749 .clone()
750 .retain(&type_id, |observer| observer(self));
751 }
752
753 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
754 callback(self);
755 }
756
757 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
758 /// so it can be held across `await` points.
759 pub fn to_async(&self) -> AsyncAppContext {
760 AsyncAppContext {
761 app: unsafe { mem::transmute(self.this.clone()) },
762 background_executor: self.background_executor.clone(),
763 foreground_executor: self.foreground_executor.clone(),
764 }
765 }
766
767 /// Obtains a reference to the executor, which can be used to spawn futures.
768 pub fn background_executor(&self) -> &BackgroundExecutor {
769 &self.background_executor
770 }
771
772 /// Obtains a reference to the executor, which can be used to spawn futures.
773 pub fn foreground_executor(&self) -> &ForegroundExecutor {
774 &self.foreground_executor
775 }
776
777 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
778 /// with AsyncAppContext, which allows the application state to be accessed across await points.
779 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
780 where
781 Fut: Future<Output = R> + 'static,
782 R: 'static,
783 {
784 self.foreground_executor.spawn(f(self.to_async()))
785 }
786
787 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
788 /// that are currently on the stack to be returned to the app.
789 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
790 self.push_effect(Effect::Defer {
791 callback: Box::new(f),
792 });
793 }
794
795 /// Accessor for the application's asset source, which is provided when constructing the `App`.
796 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
797 &self.asset_source
798 }
799
800 /// Accessor for the text system.
801 pub fn text_system(&self) -> &Arc<TextSystem> {
802 &self.text_system
803 }
804
805 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
806 pub fn text_style(&self) -> TextStyle {
807 let mut style = TextStyle::default();
808 for refinement in &self.text_style_stack {
809 style.refine(refinement);
810 }
811 style
812 }
813
814 /// Check whether a global of the given type has been assigned.
815 pub fn has_global<G: 'static>(&self) -> bool {
816 self.globals_by_type.contains_key(&TypeId::of::<G>())
817 }
818
819 /// Access the global of the given type. Panics if a global for that type has not been assigned.
820 #[track_caller]
821 pub fn global<G: 'static>(&self) -> &G {
822 self.globals_by_type
823 .get(&TypeId::of::<G>())
824 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
825 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
826 .unwrap()
827 }
828
829 /// Access the global of the given type if a value has been assigned.
830 pub fn try_global<G: 'static>(&self) -> Option<&G> {
831 self.globals_by_type
832 .get(&TypeId::of::<G>())
833 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
834 }
835
836 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
837 #[track_caller]
838 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
839 let global_type = TypeId::of::<G>();
840 self.push_effect(Effect::NotifyGlobalObservers { global_type });
841 self.globals_by_type
842 .get_mut(&global_type)
843 .and_then(|any_state| any_state.downcast_mut::<G>())
844 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
845 .unwrap()
846 }
847
848 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
849 /// yet been assigned.
850 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
851 let global_type = TypeId::of::<G>();
852 self.push_effect(Effect::NotifyGlobalObservers { global_type });
853 self.globals_by_type
854 .entry(global_type)
855 .or_insert_with(|| Box::new(G::default()))
856 .downcast_mut::<G>()
857 .unwrap()
858 }
859
860 /// Set the value of the global of the given type.
861 pub fn set_global<G: Any>(&mut self, global: G) {
862 let global_type = TypeId::of::<G>();
863 self.push_effect(Effect::NotifyGlobalObservers { global_type });
864 self.globals_by_type.insert(global_type, Box::new(global));
865 }
866
867 /// Clear all stored globals. Does not notify global observers.
868 #[cfg(any(test, feature = "test-support"))]
869 pub fn clear_globals(&mut self) {
870 self.globals_by_type.drain();
871 }
872
873 /// Remove the global of the given type from the app context. Does not notify global observers.
874 pub fn remove_global<G: Any>(&mut self) -> G {
875 let global_type = TypeId::of::<G>();
876 *self
877 .globals_by_type
878 .remove(&global_type)
879 .unwrap_or_else(|| panic!("no global added for {}", std::any::type_name::<G>()))
880 .downcast()
881 .unwrap()
882 }
883
884 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
885 /// your closure with mutable access to the `AppContext` and the global simultaneously.
886 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
887 let mut global = self.lease_global::<G>();
888 let result = f(&mut global, self);
889 self.end_global_lease(global);
890 result
891 }
892
893 /// Register a callback to be invoked when a global of the given type is updated.
894 pub fn observe_global<G: 'static>(
895 &mut self,
896 mut f: impl FnMut(&mut Self) + 'static,
897 ) -> Subscription {
898 let (subscription, activate) = self.global_observers.insert(
899 TypeId::of::<G>(),
900 Box::new(move |cx| {
901 f(cx);
902 true
903 }),
904 );
905 self.defer(move |_| activate());
906 subscription
907 }
908
909 /// Move the global of the given type to the stack.
910 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
911 GlobalLease::new(
912 self.globals_by_type
913 .remove(&TypeId::of::<G>())
914 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
915 .unwrap(),
916 )
917 }
918
919 /// Restore the global of the given type after it is moved to the stack.
920 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
921 let global_type = TypeId::of::<G>();
922 self.push_effect(Effect::NotifyGlobalObservers { global_type });
923 self.globals_by_type.insert(global_type, lease.global);
924 }
925
926 pub fn observe_new_views<V: 'static>(
927 &mut self,
928 on_new: impl 'static + Fn(&mut V, &mut ViewContext<V>),
929 ) -> Subscription {
930 let (subscription, activate) = self.new_view_observers.insert(
931 TypeId::of::<V>(),
932 Box::new(move |any_view: AnyView, cx: &mut WindowContext| {
933 any_view
934 .downcast::<V>()
935 .unwrap()
936 .update(cx, |view_state, cx| {
937 on_new(view_state, cx);
938 })
939 }),
940 );
941 activate();
942 subscription
943 }
944
945 pub fn observe_release<E, T>(
946 &mut self,
947 handle: &E,
948 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
949 ) -> Subscription
950 where
951 E: Entity<T>,
952 T: 'static,
953 {
954 let (subscription, activate) = self.release_listeners.insert(
955 handle.entity_id(),
956 Box::new(move |entity, cx| {
957 let entity = entity.downcast_mut().expect("invalid entity type");
958 on_release(entity, cx)
959 }),
960 );
961 activate();
962 subscription
963 }
964
965 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
966 self.text_style_stack.push(text_style);
967 }
968
969 pub(crate) fn pop_text_style(&mut self) {
970 self.text_style_stack.pop();
971 }
972
973 /// Register key bindings.
974 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
975 self.keymap.lock().add_bindings(bindings);
976 self.pending_effects.push_back(Effect::Refresh);
977 }
978
979 /// Register a global listener for actions invoked via the keyboard.
980 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
981 self.global_action_listeners
982 .entry(TypeId::of::<A>())
983 .or_default()
984 .push(Rc::new(move |action, phase, cx| {
985 if phase == DispatchPhase::Bubble {
986 let action = action.downcast_ref().unwrap();
987 listener(action, cx)
988 }
989 }));
990 }
991
992 /// Event handlers propagate events by default. Call this method to stop dispatching to
993 /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
994 /// the opposite of [propagate]. It's also possible to cancel a call to [propagate] by
995 /// calling this method before effects are flushed.
996 pub fn stop_propagation(&mut self) {
997 self.propagate_event = false;
998 }
999
1000 /// Action handlers stop propagation by default during the bubble phase of action dispatch
1001 /// dispatching to action handlers higher in the element tree. This is the opposite of
1002 /// [stop_propagation]. It's also possible to cancel a call to [stop_propagate] by calling
1003 /// this method before effects are flushed.
1004 pub fn propagate(&mut self) {
1005 self.propagate_event = true;
1006 }
1007
1008 pub fn build_action(
1009 &self,
1010 name: &str,
1011 data: Option<serde_json::Value>,
1012 ) -> Result<Box<dyn Action>> {
1013 self.actions.build_action(name, data)
1014 }
1015
1016 pub fn all_action_names(&self) -> &[SharedString] {
1017 self.actions.all_action_names()
1018 }
1019
1020 pub fn on_app_quit<Fut>(
1021 &mut self,
1022 mut on_quit: impl FnMut(&mut AppContext) -> Fut + 'static,
1023 ) -> Subscription
1024 where
1025 Fut: 'static + Future<Output = ()>,
1026 {
1027 let (subscription, activate) = self.quit_observers.insert(
1028 (),
1029 Box::new(move |cx| {
1030 let future = on_quit(cx);
1031 async move { future.await }.boxed_local()
1032 }),
1033 );
1034 activate();
1035 subscription
1036 }
1037
1038 pub(crate) fn clear_pending_keystrokes(&mut self) {
1039 for window in self.windows() {
1040 window
1041 .update(self, |_, cx| {
1042 cx.window
1043 .rendered_frame
1044 .dispatch_tree
1045 .clear_pending_keystrokes();
1046 cx.window
1047 .next_frame
1048 .dispatch_tree
1049 .clear_pending_keystrokes();
1050 })
1051 .ok();
1052 }
1053 }
1054
1055 pub fn is_action_available(&mut self, action: &dyn Action) -> bool {
1056 if let Some(window) = self.active_window() {
1057 if let Ok(window_action_available) =
1058 window.update(self, |_, cx| cx.is_action_available(action))
1059 {
1060 return window_action_available;
1061 }
1062 }
1063
1064 self.global_action_listeners
1065 .contains_key(&action.as_any().type_id())
1066 }
1067
1068 pub fn set_menus(&mut self, menus: Vec<Menu>) {
1069 self.platform.set_menus(menus, &self.keymap.lock());
1070 }
1071
1072 pub fn dispatch_action(&mut self, action: &dyn Action) {
1073 if let Some(active_window) = self.active_window() {
1074 active_window
1075 .update(self, |_, cx| cx.dispatch_action(action.boxed_clone()))
1076 .log_err();
1077 } else {
1078 self.propagate_event = true;
1079
1080 if let Some(mut global_listeners) = self
1081 .global_action_listeners
1082 .remove(&action.as_any().type_id())
1083 {
1084 for listener in &global_listeners {
1085 listener(action.as_any(), DispatchPhase::Capture, self);
1086 if !self.propagate_event {
1087 break;
1088 }
1089 }
1090
1091 global_listeners.extend(
1092 self.global_action_listeners
1093 .remove(&action.as_any().type_id())
1094 .unwrap_or_default(),
1095 );
1096
1097 self.global_action_listeners
1098 .insert(action.as_any().type_id(), global_listeners);
1099 }
1100
1101 if self.propagate_event {
1102 if let Some(mut global_listeners) = self
1103 .global_action_listeners
1104 .remove(&action.as_any().type_id())
1105 {
1106 for listener in global_listeners.iter().rev() {
1107 listener(action.as_any(), DispatchPhase::Bubble, self);
1108 if !self.propagate_event {
1109 break;
1110 }
1111 }
1112
1113 global_listeners.extend(
1114 self.global_action_listeners
1115 .remove(&action.as_any().type_id())
1116 .unwrap_or_default(),
1117 );
1118
1119 self.global_action_listeners
1120 .insert(action.as_any().type_id(), global_listeners);
1121 }
1122 }
1123 }
1124 }
1125
1126 pub fn has_active_drag(&self) -> bool {
1127 self.active_drag.is_some()
1128 }
1129}
1130
1131impl Context for AppContext {
1132 type Result<T> = T;
1133
1134 /// Build an entity that is owned by the application. The given function will be invoked with
1135 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
1136 /// which can be used to access the entity in a context.
1137 fn build_model<T: 'static>(
1138 &mut self,
1139 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1140 ) -> Model<T> {
1141 self.update(|cx| {
1142 let slot = cx.entities.reserve();
1143 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
1144 cx.entities.insert(slot, entity)
1145 })
1146 }
1147
1148 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
1149 /// entity along with a `ModelContext` for the entity.
1150 fn update_model<T: 'static, R>(
1151 &mut self,
1152 model: &Model<T>,
1153 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1154 ) -> R {
1155 self.update(|cx| {
1156 let mut entity = cx.entities.lease(model);
1157 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
1158 cx.entities.end_lease(entity);
1159 result
1160 })
1161 }
1162
1163 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
1164 where
1165 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1166 {
1167 self.update(|cx| {
1168 let mut window = cx
1169 .windows
1170 .get_mut(handle.id)
1171 .ok_or_else(|| anyhow!("window not found"))?
1172 .take()
1173 .unwrap();
1174
1175 let root_view = window.root_view.clone().unwrap();
1176 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
1177
1178 if window.removed {
1179 cx.windows.remove(handle.id);
1180 } else {
1181 cx.windows
1182 .get_mut(handle.id)
1183 .ok_or_else(|| anyhow!("window not found"))?
1184 .replace(window);
1185 }
1186
1187 Ok(result)
1188 })
1189 }
1190
1191 fn read_model<T, R>(
1192 &self,
1193 handle: &Model<T>,
1194 read: impl FnOnce(&T, &AppContext) -> R,
1195 ) -> Self::Result<R>
1196 where
1197 T: 'static,
1198 {
1199 let entity = self.entities.read(handle);
1200 read(entity, self)
1201 }
1202
1203 fn read_window<T, R>(
1204 &self,
1205 window: &WindowHandle<T>,
1206 read: impl FnOnce(View<T>, &AppContext) -> R,
1207 ) -> Result<R>
1208 where
1209 T: 'static,
1210 {
1211 let window = self
1212 .windows
1213 .get(window.id)
1214 .ok_or_else(|| anyhow!("window not found"))?
1215 .as_ref()
1216 .unwrap();
1217
1218 let root_view = window.root_view.clone().unwrap();
1219 let view = root_view
1220 .downcast::<T>()
1221 .map_err(|_| anyhow!("root view's type has changed"))?;
1222
1223 Ok(read(view, self))
1224 }
1225}
1226
1227/// These effects are processed at the end of each application update cycle.
1228pub(crate) enum Effect {
1229 Notify {
1230 emitter: EntityId,
1231 },
1232 Emit {
1233 emitter: EntityId,
1234 event_type: TypeId,
1235 event: Box<dyn Any>,
1236 },
1237 FocusChanged {
1238 window_handle: AnyWindowHandle,
1239 focused: Option<FocusId>,
1240 },
1241 Refresh,
1242 NotifyGlobalObservers {
1243 global_type: TypeId,
1244 },
1245 Defer {
1246 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
1247 },
1248}
1249
1250/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
1251pub(crate) struct GlobalLease<G: 'static> {
1252 global: Box<dyn Any>,
1253 global_type: PhantomData<G>,
1254}
1255
1256impl<G: 'static> GlobalLease<G> {
1257 fn new(global: Box<dyn Any>) -> Self {
1258 GlobalLease {
1259 global,
1260 global_type: PhantomData,
1261 }
1262 }
1263}
1264
1265impl<G: 'static> Deref for GlobalLease<G> {
1266 type Target = G;
1267
1268 fn deref(&self) -> &Self::Target {
1269 self.global.downcast_ref().unwrap()
1270 }
1271}
1272
1273impl<G: 'static> DerefMut for GlobalLease<G> {
1274 fn deref_mut(&mut self) -> &mut Self::Target {
1275 self.global.downcast_mut().unwrap()
1276 }
1277}
1278
1279/// Contains state associated with an active drag operation, started by dragging an element
1280/// within the window or by dragging into the app from the underlying platform.
1281pub struct AnyDrag {
1282 pub view: AnyView,
1283 pub cursor_offset: Point<Pixels>,
1284}
1285
1286#[derive(Clone)]
1287pub(crate) struct AnyTooltip {
1288 pub view: AnyView,
1289 pub cursor_offset: Point<Pixels>,
1290}