1mod async_context;
2mod entity_map;
3mod model_context;
4#[cfg(any(test, feature = "test-support"))]
5mod test_context;
6
7pub use async_context::*;
8pub use entity_map::*;
9pub use model_context::*;
10use refineable::Refineable;
11use smallvec::SmallVec;
12#[cfg(any(test, feature = "test-support"))]
13pub use test_context::*;
14
15use crate::{
16 current_platform, image_cache::ImageCache, Action, AnyBox, AnyView, AnyWindowHandle,
17 AppMetadata, AssetSource, BackgroundExecutor, ClipboardItem, Context, DispatchPhase, DisplayId,
18 Entity, FocusEvent, FocusHandle, FocusId, ForegroundExecutor, KeyBinding, Keymap, LayoutId,
19 Pixels, Platform, Point, Render, SharedString, SubscriberSet, Subscription, SvgRenderer, Task,
20 TextStyle, TextStyleRefinement, TextSystem, View, Window, WindowContext, WindowHandle,
21 WindowId,
22};
23use anyhow::{anyhow, Result};
24use collections::{HashMap, HashSet, VecDeque};
25use futures::{future::LocalBoxFuture, Future};
26use parking_lot::Mutex;
27use slotmap::SlotMap;
28use std::{
29 any::{type_name, Any, TypeId},
30 cell::RefCell,
31 marker::PhantomData,
32 mem,
33 ops::{Deref, DerefMut},
34 path::PathBuf,
35 rc::{Rc, Weak},
36 sync::{atomic::Ordering::SeqCst, Arc},
37 time::Duration,
38};
39use util::http::{self, HttpClient};
40
41pub struct App(Rc<RefCell<AppContext>>);
42
43/// Represents an application before it is fully launched. Once your app is
44/// configured, you'll start the app with `App::run`.
45impl App {
46 /// Builds an app with the given asset source.
47 pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
48 Self(AppContext::new(
49 current_platform(),
50 asset_source,
51 http::client(),
52 ))
53 }
54
55 /// Start the application. The provided callback will be called once the
56 /// app is fully launched.
57 pub fn run<F>(self, on_finish_launching: F)
58 where
59 F: 'static + FnOnce(&mut AppContext),
60 {
61 let this = self.0.clone();
62 let platform = self.0.borrow().platform.clone();
63 platform.run(Box::new(move || {
64 let cx = &mut *this.borrow_mut();
65 on_finish_launching(cx);
66 }));
67 }
68
69 /// Register a handler to be invoked when the platform instructs the application
70 /// to open one or more URLs.
71 pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
72 where
73 F: 'static + FnMut(Vec<String>, &mut AppContext),
74 {
75 let this = Rc::downgrade(&self.0);
76 self.0.borrow().platform.on_open_urls(Box::new(move |urls| {
77 if let Some(app) = this.upgrade() {
78 callback(urls, &mut *app.borrow_mut());
79 }
80 }));
81 self
82 }
83
84 pub fn on_reopen<F>(&self, mut callback: F) -> &Self
85 where
86 F: 'static + FnMut(&mut AppContext),
87 {
88 let this = Rc::downgrade(&self.0);
89 self.0.borrow_mut().platform.on_reopen(Box::new(move || {
90 if let Some(app) = this.upgrade() {
91 callback(&mut app.borrow_mut());
92 }
93 }));
94 self
95 }
96
97 pub fn metadata(&self) -> AppMetadata {
98 self.0.borrow().app_metadata.clone()
99 }
100
101 pub fn background_executor(&self) -> BackgroundExecutor {
102 self.0.borrow().background_executor.clone()
103 }
104
105 pub fn foreground_executor(&self) -> ForegroundExecutor {
106 self.0.borrow().foreground_executor.clone()
107 }
108
109 pub fn text_system(&self) -> Arc<TextSystem> {
110 self.0.borrow().text_system.clone()
111 }
112}
113
114type ActionBuilder = fn(json: Option<serde_json::Value>) -> anyhow::Result<Box<dyn Action>>;
115type FrameCallback = Box<dyn FnOnce(&mut WindowContext)>;
116type Handler = Box<dyn FnMut(&mut AppContext) -> bool + 'static>;
117type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + 'static>;
118type QuitHandler = Box<dyn FnOnce(&mut AppContext) -> LocalBoxFuture<'static, ()> + 'static>;
119type ReleaseListener = Box<dyn FnOnce(&mut dyn Any, &mut AppContext) + 'static>;
120
121pub struct AppContext {
122 this: Weak<RefCell<AppContext>>,
123 pub(crate) platform: Rc<dyn Platform>,
124 app_metadata: AppMetadata,
125 text_system: Arc<TextSystem>,
126 flushing_effects: bool,
127 pending_updates: usize,
128 pub(crate) active_drag: Option<AnyDrag>,
129 pub(crate) next_frame_callbacks: HashMap<DisplayId, Vec<FrameCallback>>,
130 pub(crate) background_executor: BackgroundExecutor,
131 pub(crate) foreground_executor: ForegroundExecutor,
132 pub(crate) svg_renderer: SvgRenderer,
133 asset_source: Arc<dyn AssetSource>,
134 pub(crate) image_cache: ImageCache,
135 pub(crate) text_style_stack: Vec<TextStyleRefinement>,
136 pub(crate) globals_by_type: HashMap<TypeId, AnyBox>,
137 pub(crate) entities: EntityMap,
138 pub(crate) windows: SlotMap<WindowId, Option<Window>>,
139 pub(crate) keymap: Arc<Mutex<Keymap>>,
140 pub(crate) global_action_listeners:
141 HashMap<TypeId, Vec<Box<dyn Fn(&dyn Action, DispatchPhase, &mut Self)>>>,
142 action_builders: HashMap<SharedString, ActionBuilder>,
143 pending_effects: VecDeque<Effect>,
144 pub(crate) pending_notifications: HashSet<EntityId>,
145 pub(crate) pending_global_notifications: HashSet<TypeId>,
146 pub(crate) observers: SubscriberSet<EntityId, Handler>,
147 pub(crate) event_listeners: SubscriberSet<EntityId, Listener>,
148 pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
149 pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
150 pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
151 pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
152 pub(crate) propagate_event: bool,
153}
154
155impl AppContext {
156 pub(crate) fn new(
157 platform: Rc<dyn Platform>,
158 asset_source: Arc<dyn AssetSource>,
159 http_client: Arc<dyn HttpClient>,
160 ) -> Rc<RefCell<Self>> {
161 let executor = platform.background_executor();
162 let foreground_executor = platform.foreground_executor();
163 assert!(
164 executor.is_main_thread(),
165 "must construct App on main thread"
166 );
167
168 let text_system = Arc::new(TextSystem::new(platform.text_system()));
169 let entities = EntityMap::new();
170
171 let app_metadata = AppMetadata {
172 os_name: platform.os_name(),
173 os_version: platform.os_version().ok(),
174 app_version: platform.app_version().ok(),
175 };
176
177 Rc::new_cyclic(|this| {
178 RefCell::new(AppContext {
179 this: this.clone(),
180 text_system,
181 platform,
182 app_metadata,
183 flushing_effects: false,
184 pending_updates: 0,
185 next_frame_callbacks: Default::default(),
186 background_executor: executor,
187 foreground_executor,
188 svg_renderer: SvgRenderer::new(asset_source.clone()),
189 asset_source,
190 image_cache: ImageCache::new(http_client),
191 text_style_stack: Vec::new(),
192 globals_by_type: HashMap::default(),
193 entities,
194 windows: SlotMap::with_key(),
195 keymap: Arc::new(Mutex::new(Keymap::default())),
196 global_action_listeners: HashMap::default(),
197 action_builders: HashMap::default(),
198 pending_effects: VecDeque::new(),
199 pending_notifications: HashSet::default(),
200 pending_global_notifications: HashSet::default(),
201 observers: SubscriberSet::new(),
202 event_listeners: SubscriberSet::new(),
203 release_listeners: SubscriberSet::new(),
204 global_observers: SubscriberSet::new(),
205 quit_observers: SubscriberSet::new(),
206 layout_id_buffer: Default::default(),
207 propagate_event: true,
208 active_drag: None,
209 })
210 })
211 }
212
213 /// Quit the application gracefully. Handlers registered with `ModelContext::on_app_quit`
214 /// will be given 100ms to complete before exiting.
215 pub fn quit(&mut self) {
216 let mut futures = Vec::new();
217
218 for observer in self.quit_observers.remove(&()) {
219 futures.push(observer(self));
220 }
221
222 self.windows.clear();
223 self.flush_effects();
224
225 let futures = futures::future::join_all(futures);
226 if self
227 .background_executor
228 .block_with_timeout(Duration::from_millis(100), futures)
229 .is_err()
230 {
231 log::error!("timed out waiting on app_will_quit");
232 }
233
234 self.globals_by_type.clear();
235 }
236
237 pub fn app_metadata(&self) -> AppMetadata {
238 self.app_metadata.clone()
239 }
240
241 /// Schedules all windows in the application to be redrawn. This can be called
242 /// multiple times in an update cycle and still result in a single redraw.
243 pub fn refresh(&mut self) {
244 self.pending_effects.push_back(Effect::Refresh);
245 }
246 pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
247 self.pending_updates += 1;
248 let result = update(self);
249 if !self.flushing_effects && self.pending_updates == 1 {
250 self.flushing_effects = true;
251 self.flush_effects();
252 self.flushing_effects = false;
253 }
254 self.pending_updates -= 1;
255 result
256 }
257
258 pub fn windows(&self) -> Vec<AnyWindowHandle> {
259 self.windows
260 .values()
261 .filter_map(|window| Some(window.as_ref()?.handle.clone()))
262 .collect()
263 }
264
265 pub(crate) fn update_window<R>(
266 &mut self,
267 handle: AnyWindowHandle,
268 update: impl FnOnce(AnyView, &mut WindowContext) -> R,
269 ) -> Result<R> {
270 self.update(|cx| {
271 let mut window = cx
272 .windows
273 .get_mut(handle.id)
274 .ok_or_else(|| anyhow!("window not found"))?
275 .take()
276 .unwrap();
277
278 let root_view = window.root_view.clone().unwrap();
279 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
280
281 cx.windows
282 .get_mut(handle.id)
283 .ok_or_else(|| anyhow!("window not found"))?
284 .replace(window);
285
286 Ok(result)
287 })
288 }
289
290 /// Opens a new window with the given option and the root view returned by the given function.
291 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
292 /// functionality.
293 pub fn open_window<V: Render>(
294 &mut self,
295 options: crate::WindowOptions,
296 build_root_view: impl FnOnce(&mut WindowContext) -> View<V> + 'static,
297 ) -> WindowHandle<V> {
298 self.update(|cx| {
299 let id = cx.windows.insert(None);
300 let handle = WindowHandle::new(id);
301 let mut window = Window::new(handle.into(), options, cx);
302 let root_view = build_root_view(&mut WindowContext::new(cx, &mut window));
303 window.root_view.replace(root_view.into());
304 cx.windows.get_mut(id).unwrap().replace(window);
305 handle
306 })
307 }
308
309 pub(crate) fn platform(&self) -> &Rc<dyn Platform> {
310 &self.platform
311 }
312
313 /// Instructs the platform to activate the application by bringing it to the foreground.
314 pub fn activate(&self, ignoring_other_apps: bool) {
315 self.platform().activate(ignoring_other_apps);
316 }
317
318 /// Writes data to the platform clipboard.
319 pub fn write_to_clipboard(&self, item: ClipboardItem) {
320 self.platform().write_to_clipboard(item)
321 }
322
323 /// Reads data from the platform clipboard.
324 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
325 self.platform().read_from_clipboard()
326 }
327
328 /// Writes credentials to the platform keychain.
329 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
330 self.platform().write_credentials(url, username, password)
331 }
332
333 /// Reads credentials from the platform keychain.
334 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
335 self.platform().read_credentials(url)
336 }
337
338 /// Deletes credentials from the platform keychain.
339 pub fn delete_credentials(&self, url: &str) -> Result<()> {
340 self.platform().delete_credentials(url)
341 }
342
343 /// Directs the platform's default browser to open the given URL.
344 pub fn open_url(&self, url: &str) {
345 self.platform().open_url(url);
346 }
347
348 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
349 self.platform().path_for_auxiliary_executable(name)
350 }
351
352 pub(crate) fn push_effect(&mut self, effect: Effect) {
353 match &effect {
354 Effect::Notify { emitter } => {
355 if !self.pending_notifications.insert(*emitter) {
356 return;
357 }
358 }
359 Effect::NotifyGlobalObservers { global_type } => {
360 if !self.pending_global_notifications.insert(*global_type) {
361 return;
362 }
363 }
364 _ => {}
365 };
366
367 self.pending_effects.push_back(effect);
368 }
369
370 /// Called at the end of AppContext::update to complete any side effects
371 /// such as notifying observers, emitting events, etc. Effects can themselves
372 /// cause effects, so we continue looping until all effects are processed.
373 fn flush_effects(&mut self) {
374 loop {
375 self.release_dropped_entities();
376 self.release_dropped_focus_handles();
377 if let Some(effect) = self.pending_effects.pop_front() {
378 match effect {
379 Effect::Notify { emitter } => {
380 self.apply_notify_effect(emitter);
381 }
382 Effect::Emit { emitter, event } => self.apply_emit_effect(emitter, event),
383 Effect::FocusChanged {
384 window_handle,
385 focused,
386 } => {
387 self.apply_focus_changed_effect(window_handle, focused);
388 }
389 Effect::Refresh => {
390 self.apply_refresh_effect();
391 }
392 Effect::NotifyGlobalObservers { global_type } => {
393 self.apply_notify_global_observers_effect(global_type);
394 }
395 Effect::Defer { callback } => {
396 self.apply_defer_effect(callback);
397 }
398 }
399 } else {
400 break;
401 }
402 }
403
404 let dirty_window_ids = self
405 .windows
406 .iter()
407 .filter_map(|(_, window)| {
408 let window = window.as_ref().unwrap();
409 if window.dirty {
410 Some(window.handle.clone())
411 } else {
412 None
413 }
414 })
415 .collect::<SmallVec<[_; 8]>>();
416
417 for dirty_window_handle in dirty_window_ids {
418 dirty_window_handle.update(self, |_, cx| cx.draw()).unwrap();
419 }
420 }
421
422 /// Repeatedly called during `flush_effects` to release any entities whose
423 /// reference count has become zero. We invoke any release observers before dropping
424 /// each entity.
425 fn release_dropped_entities(&mut self) {
426 loop {
427 let dropped = self.entities.take_dropped();
428 if dropped.is_empty() {
429 break;
430 }
431
432 for (entity_id, mut entity) in dropped {
433 self.observers.remove(&entity_id);
434 self.event_listeners.remove(&entity_id);
435 for release_callback in self.release_listeners.remove(&entity_id) {
436 release_callback(entity.as_mut(), self);
437 }
438 }
439 }
440 }
441
442 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
443 /// For now, we simply blur the window if this happens, but we may want to support invoking
444 /// a window blur handler to restore focus to some logical element.
445 fn release_dropped_focus_handles(&mut self) {
446 for window_handle in self.windows() {
447 window_handle
448 .update(self, |_, cx| {
449 let mut blur_window = false;
450 let focus = cx.window.focus;
451 cx.window.focus_handles.write().retain(|handle_id, count| {
452 if count.load(SeqCst) == 0 {
453 if focus == Some(handle_id) {
454 blur_window = true;
455 }
456 false
457 } else {
458 true
459 }
460 });
461
462 if blur_window {
463 cx.blur();
464 }
465 })
466 .unwrap();
467 }
468 }
469
470 fn apply_notify_effect(&mut self, emitter: EntityId) {
471 self.pending_notifications.remove(&emitter);
472 self.observers
473 .clone()
474 .retain(&emitter, |handler| handler(self));
475 }
476
477 fn apply_emit_effect(&mut self, emitter: EntityId, event: Box<dyn Any>) {
478 self.event_listeners
479 .clone()
480 .retain(&emitter, |handler| handler(event.as_ref(), self));
481 }
482
483 fn apply_focus_changed_effect(
484 &mut self,
485 window_handle: AnyWindowHandle,
486 focused: Option<FocusId>,
487 ) {
488 window_handle
489 .update(self, |_, cx| {
490 if cx.window.focus == focused {
491 let mut listeners = mem::take(&mut cx.window.focus_listeners);
492 let focused = focused
493 .map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
494 let blurred = cx
495 .window
496 .last_blur
497 .take()
498 .unwrap()
499 .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
500 if focused.is_some() || blurred.is_some() {
501 let event = FocusEvent { focused, blurred };
502 for listener in &listeners {
503 listener(&event, cx);
504 }
505 }
506
507 listeners.extend(cx.window.focus_listeners.drain(..));
508 cx.window.focus_listeners = listeners;
509 }
510 })
511 .ok();
512 }
513
514 fn apply_refresh_effect(&mut self) {
515 for window in self.windows.values_mut() {
516 if let Some(window) = window.as_mut() {
517 window.dirty = true;
518 }
519 }
520 }
521
522 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
523 self.pending_global_notifications.remove(&type_id);
524 self.global_observers
525 .clone()
526 .retain(&type_id, |observer| observer(self));
527 }
528
529 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
530 callback(self);
531 }
532
533 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
534 /// so it can be held across `await` points.
535 pub fn to_async(&self) -> AsyncAppContext {
536 AsyncAppContext {
537 app: unsafe { mem::transmute(self.this.clone()) },
538 background_executor: self.background_executor.clone(),
539 foreground_executor: self.foreground_executor.clone(),
540 }
541 }
542
543 /// Obtains a reference to the executor, which can be used to spawn futures.
544 pub fn background_executor(&self) -> &BackgroundExecutor {
545 &self.background_executor
546 }
547
548 /// Obtains a reference to the executor, which can be used to spawn futures.
549 pub fn foreground_executor(&self) -> &ForegroundExecutor {
550 &self.foreground_executor
551 }
552
553 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
554 /// with AsyncAppContext, which allows the application state to be accessed across await points.
555 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
556 where
557 Fut: Future<Output = R> + 'static,
558 R: 'static,
559 {
560 self.foreground_executor.spawn(f(self.to_async()))
561 }
562
563 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
564 /// that are currently on the stack to be returned to the app.
565 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
566 self.push_effect(Effect::Defer {
567 callback: Box::new(f),
568 });
569 }
570
571 /// Accessor for the application's asset source, which is provided when constructing the `App`.
572 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
573 &self.asset_source
574 }
575
576 /// Accessor for the text system.
577 pub fn text_system(&self) -> &Arc<TextSystem> {
578 &self.text_system
579 }
580
581 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
582 pub fn text_style(&self) -> TextStyle {
583 let mut style = TextStyle::default();
584 for refinement in &self.text_style_stack {
585 style.refine(refinement);
586 }
587 style
588 }
589
590 /// Check whether a global of the given type has been assigned.
591 pub fn has_global<G: 'static>(&self) -> bool {
592 self.globals_by_type.contains_key(&TypeId::of::<G>())
593 }
594
595 /// Access the global of the given type. Panics if a global for that type has not been assigned.
596 pub fn global<G: 'static>(&self) -> &G {
597 self.globals_by_type
598 .get(&TypeId::of::<G>())
599 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
600 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
601 .unwrap()
602 }
603
604 /// Access the global of the given type if a value has been assigned.
605 pub fn try_global<G: 'static>(&self) -> Option<&G> {
606 self.globals_by_type
607 .get(&TypeId::of::<G>())
608 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
609 }
610
611 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
612 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
613 let global_type = TypeId::of::<G>();
614 self.push_effect(Effect::NotifyGlobalObservers { global_type });
615 self.globals_by_type
616 .get_mut(&global_type)
617 .and_then(|any_state| any_state.downcast_mut::<G>())
618 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
619 .unwrap()
620 }
621
622 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
623 /// yet been assigned.
624 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
625 let global_type = TypeId::of::<G>();
626 self.push_effect(Effect::NotifyGlobalObservers { global_type });
627 self.globals_by_type
628 .entry(global_type)
629 .or_insert_with(|| Box::new(G::default()))
630 .downcast_mut::<G>()
631 .unwrap()
632 }
633
634 /// Set the value of the global of the given type.
635 pub fn set_global<G: Any>(&mut self, global: G) {
636 let global_type = TypeId::of::<G>();
637 self.push_effect(Effect::NotifyGlobalObservers { global_type });
638 self.globals_by_type.insert(global_type, Box::new(global));
639 }
640
641 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
642 /// your closure with mutable access to the `AppContext` and the global simultaneously.
643 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
644 let mut global = self.lease_global::<G>();
645 let result = f(&mut global, self);
646 self.end_global_lease(global);
647 result
648 }
649
650 /// Register a callback to be invoked when a global of the given type is updated.
651 pub fn observe_global<G: 'static>(
652 &mut self,
653 mut f: impl FnMut(&mut Self) + 'static,
654 ) -> Subscription {
655 self.global_observers.insert(
656 TypeId::of::<G>(),
657 Box::new(move |cx| {
658 f(cx);
659 true
660 }),
661 )
662 }
663
664 pub fn all_action_names<'a>(&'a self) -> impl Iterator<Item = SharedString> + 'a {
665 self.action_builders.keys().cloned()
666 }
667
668 /// Move the global of the given type to the stack.
669 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
670 GlobalLease::new(
671 self.globals_by_type
672 .remove(&TypeId::of::<G>())
673 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
674 .unwrap(),
675 )
676 }
677
678 /// Restore the global of the given type after it is moved to the stack.
679 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
680 let global_type = TypeId::of::<G>();
681 self.push_effect(Effect::NotifyGlobalObservers { global_type });
682 self.globals_by_type.insert(global_type, lease.global);
683 }
684
685 pub fn observe_release<E, T>(
686 &mut self,
687 handle: &E,
688 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
689 ) -> Subscription
690 where
691 E: Entity<T>,
692 T: 'static,
693 {
694 self.release_listeners.insert(
695 handle.entity_id(),
696 Box::new(move |entity, cx| {
697 let entity = entity.downcast_mut().expect("invalid entity type");
698 on_release(entity, cx)
699 }),
700 )
701 }
702
703 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
704 self.text_style_stack.push(text_style);
705 }
706
707 pub(crate) fn pop_text_style(&mut self) {
708 self.text_style_stack.pop();
709 }
710
711 /// Register key bindings.
712 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
713 self.keymap.lock().add_bindings(bindings);
714 self.pending_effects.push_back(Effect::Refresh);
715 }
716
717 /// Register a global listener for actions invoked via the keyboard.
718 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
719 self.global_action_listeners
720 .entry(TypeId::of::<A>())
721 .or_default()
722 .push(Box::new(move |action, phase, cx| {
723 if phase == DispatchPhase::Bubble {
724 let action = action.as_any().downcast_ref().unwrap();
725 listener(action, cx)
726 }
727 }));
728 }
729
730 /// Register an action type to allow it to be referenced in keymaps.
731 pub fn register_action_type<A: Action>(&mut self) {
732 self.action_builders.insert(A::qualified_name(), A::build);
733 }
734
735 /// Construct an action based on its name and parameters.
736 pub fn build_action(
737 &mut self,
738 name: &str,
739 params: Option<serde_json::Value>,
740 ) -> Result<Box<dyn Action>> {
741 let build = self
742 .action_builders
743 .get(name)
744 .ok_or_else(|| anyhow!("no action type registered for {}", name))?;
745 (build)(params)
746 }
747
748 /// Halt propagation of a mouse event, keyboard event, or action. This prevents listeners
749 /// that have not yet been invoked from receiving the event.
750 pub fn stop_propagation(&mut self) {
751 self.propagate_event = false;
752 }
753}
754
755impl Context for AppContext {
756 type Result<T> = T;
757
758 /// Build an entity that is owned by the application. The given function will be invoked with
759 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
760 /// which can be used to access the entity in a context.
761 fn build_model<T: 'static>(
762 &mut self,
763 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
764 ) -> Model<T> {
765 self.update(|cx| {
766 let slot = cx.entities.reserve();
767 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
768 cx.entities.insert(slot, entity)
769 })
770 }
771
772 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
773 /// entity along with a `ModelContext` for the entity.
774 fn update_model<T: 'static, R>(
775 &mut self,
776 model: &Model<T>,
777 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
778 ) -> R {
779 self.update(|cx| {
780 let mut entity = cx.entities.lease(model);
781 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
782 cx.entities.end_lease(entity);
783 result
784 })
785 }
786
787 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
788 where
789 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
790 {
791 self.update(|cx| {
792 let mut window = cx
793 .windows
794 .get_mut(handle.id)
795 .ok_or_else(|| anyhow!("window not found"))?
796 .take()
797 .unwrap();
798
799 let root_view = window.root_view.clone().unwrap();
800 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
801 cx.windows
802 .get_mut(handle.id)
803 .ok_or_else(|| anyhow!("window not found"))?
804 .replace(window);
805
806 Ok(result)
807 })
808 }
809}
810
811/// These effects are processed at the end of each application update cycle.
812pub(crate) enum Effect {
813 Notify {
814 emitter: EntityId,
815 },
816 Emit {
817 emitter: EntityId,
818 event: Box<dyn Any>,
819 },
820 FocusChanged {
821 window_handle: AnyWindowHandle,
822 focused: Option<FocusId>,
823 },
824 Refresh,
825 NotifyGlobalObservers {
826 global_type: TypeId,
827 },
828 Defer {
829 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
830 },
831}
832
833/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
834pub(crate) struct GlobalLease<G: 'static> {
835 global: AnyBox,
836 global_type: PhantomData<G>,
837}
838
839impl<G: 'static> GlobalLease<G> {
840 fn new(global: AnyBox) -> Self {
841 GlobalLease {
842 global,
843 global_type: PhantomData,
844 }
845 }
846}
847
848impl<G: 'static> Deref for GlobalLease<G> {
849 type Target = G;
850
851 fn deref(&self) -> &Self::Target {
852 self.global.downcast_ref().unwrap()
853 }
854}
855
856impl<G: 'static> DerefMut for GlobalLease<G> {
857 fn deref_mut(&mut self) -> &mut Self::Target {
858 self.global.downcast_mut().unwrap()
859 }
860}
861
862/// Contains state associated with an active drag operation, started by dragging an element
863/// within the window or by dragging into the app from the underlying platform.
864pub(crate) struct AnyDrag {
865 pub view: AnyView,
866 pub cursor_offset: Point<Pixels>,
867}