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;
13#[cfg(any(test, feature = "test-support"))]
14pub use test_context::*;
15
16use crate::{
17 current_platform, image_cache::ImageCache, Action, AnyBox, AnyView, AnyWindowHandle,
18 AppMetadata, AssetSource, BackgroundExecutor, ClipboardItem, Context, DispatchPhase, DisplayId,
19 Entity, FocusEvent, FocusHandle, FocusId, ForegroundExecutor, KeyBinding, Keymap, LayoutId,
20 PathPromptOptions, Pixels, Platform, PlatformDisplay, Point, Render, SharedString,
21 SubscriberSet, Subscription, SvgRenderer, Task, TextStyle, TextStyleRefinement, TextSystem,
22 View, Window, WindowContext, WindowHandle, WindowId,
23};
24use anyhow::{anyhow, Result};
25use collections::{HashMap, HashSet, VecDeque};
26use futures::{channel::oneshot, future::LocalBoxFuture, Future};
27use parking_lot::Mutex;
28use slotmap::SlotMap;
29use std::{
30 any::{type_name, Any, TypeId},
31 cell::{Ref, RefCell, RefMut},
32 marker::PhantomData,
33 mem,
34 ops::{Deref, DerefMut},
35 path::{Path, PathBuf},
36 rc::{Rc, Weak},
37 sync::{atomic::Ordering::SeqCst, Arc},
38 time::Duration,
39};
40use util::http::{self, HttpClient};
41
42/// Temporary(?) wrapper around RefCell<AppContext> to help us debug any double borrows.
43/// Strongly consider removing after stabilization.
44pub struct AppCell {
45 app: RefCell<AppContext>,
46}
47
48impl AppCell {
49 #[track_caller]
50 pub fn borrow(&self) -> AppRef {
51 // let thread_id = std::thread::current().id();
52 // eprintln!("borrowed {thread_id:?}");
53 AppRef(self.app.borrow())
54 }
55
56 #[track_caller]
57 pub fn borrow_mut(&self) -> AppRefMut {
58 // let thread_id = std::thread::current().id();
59 // eprintln!("borrowed {thread_id:?}");
60 AppRefMut(self.app.borrow_mut())
61 }
62}
63
64#[derive(Deref, DerefMut)]
65pub struct AppRef<'a>(Ref<'a, AppContext>);
66
67#[derive(Deref, DerefMut)]
68pub struct AppRefMut<'a>(RefMut<'a, AppContext>);
69
70pub struct App(Rc<AppCell>);
71
72/// Represents an application before it is fully launched. Once your app is
73/// configured, you'll start the app with `App::run`.
74impl App {
75 /// Builds an app with the given asset source.
76 pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
77 Self(AppContext::new(
78 current_platform(),
79 asset_source,
80 http::client(),
81 ))
82 }
83
84 /// Start the application. The provided callback will be called once the
85 /// app is fully launched.
86 pub fn run<F>(self, on_finish_launching: F)
87 where
88 F: 'static + FnOnce(&mut AppContext),
89 {
90 let this = self.0.clone();
91 let platform = self.0.borrow().platform.clone();
92 platform.run(Box::new(move || {
93 let cx = &mut *this.borrow_mut();
94 on_finish_launching(cx);
95 }));
96 }
97
98 /// Register a handler to be invoked when the platform instructs the application
99 /// to open one or more URLs.
100 pub fn on_open_urls<F>(&self, mut callback: F) -> &Self
101 where
102 F: 'static + FnMut(Vec<String>, &mut AppContext),
103 {
104 let this = Rc::downgrade(&self.0);
105 self.0.borrow().platform.on_open_urls(Box::new(move |urls| {
106 if let Some(app) = this.upgrade() {
107 callback(urls, &mut *app.borrow_mut());
108 }
109 }));
110 self
111 }
112
113 pub fn on_reopen<F>(&self, mut callback: F) -> &Self
114 where
115 F: 'static + FnMut(&mut AppContext),
116 {
117 let this = Rc::downgrade(&self.0);
118 self.0.borrow_mut().platform.on_reopen(Box::new(move || {
119 if let Some(app) = this.upgrade() {
120 callback(&mut app.borrow_mut());
121 }
122 }));
123 self
124 }
125
126 pub fn metadata(&self) -> AppMetadata {
127 self.0.borrow().app_metadata.clone()
128 }
129
130 pub fn background_executor(&self) -> BackgroundExecutor {
131 self.0.borrow().background_executor.clone()
132 }
133
134 pub fn foreground_executor(&self) -> ForegroundExecutor {
135 self.0.borrow().foreground_executor.clone()
136 }
137
138 pub fn text_system(&self) -> Arc<TextSystem> {
139 self.0.borrow().text_system.clone()
140 }
141}
142
143type ActionBuilder = fn(json: Option<serde_json::Value>) -> anyhow::Result<Box<dyn Action>>;
144pub(crate) type FrameCallback = Box<dyn FnOnce(&mut AppContext)>;
145type Handler = Box<dyn FnMut(&mut AppContext) -> bool + 'static>;
146type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + 'static>;
147type QuitHandler = Box<dyn FnOnce(&mut AppContext) -> LocalBoxFuture<'static, ()> + 'static>;
148type ReleaseListener = Box<dyn FnOnce(&mut dyn Any, &mut AppContext) + 'static>;
149
150// struct FrameConsumer {
151// next_frame_callbacks: Vec<FrameCallback>,
152// task: Task<()>,
153// display_linker
154// }
155
156pub struct AppContext {
157 this: Weak<AppCell>,
158 pub(crate) platform: Rc<dyn Platform>,
159 app_metadata: AppMetadata,
160 text_system: Arc<TextSystem>,
161 flushing_effects: bool,
162 pending_updates: usize,
163 pub(crate) active_drag: Option<AnyDrag>,
164 pub(crate) active_tooltip: Option<AnyTooltip>,
165 pub(crate) next_frame_callbacks: HashMap<DisplayId, Vec<FrameCallback>>,
166 pub(crate) frame_consumers: HashMap<DisplayId, Task<()>>,
167 pub(crate) background_executor: BackgroundExecutor,
168 pub(crate) foreground_executor: ForegroundExecutor,
169 pub(crate) svg_renderer: SvgRenderer,
170 asset_source: Arc<dyn AssetSource>,
171 pub(crate) image_cache: ImageCache,
172 pub(crate) text_style_stack: Vec<TextStyleRefinement>,
173 pub(crate) globals_by_type: HashMap<TypeId, AnyBox>,
174 pub(crate) entities: EntityMap,
175 pub(crate) windows: SlotMap<WindowId, Option<Window>>,
176 pub(crate) keymap: Arc<Mutex<Keymap>>,
177 pub(crate) global_action_listeners:
178 HashMap<TypeId, Vec<Box<dyn Fn(&dyn Action, DispatchPhase, &mut Self)>>>,
179 action_builders: HashMap<SharedString, ActionBuilder>,
180 pending_effects: VecDeque<Effect>,
181 pub(crate) pending_notifications: HashSet<EntityId>,
182 pub(crate) pending_global_notifications: HashSet<TypeId>,
183 pub(crate) observers: SubscriberSet<EntityId, Handler>,
184 pub(crate) event_listeners: SubscriberSet<EntityId, Listener>,
185 pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
186 pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
187 pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
188 pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
189 pub(crate) propagate_event: bool,
190}
191
192impl AppContext {
193 pub(crate) fn new(
194 platform: Rc<dyn Platform>,
195 asset_source: Arc<dyn AssetSource>,
196 http_client: Arc<dyn HttpClient>,
197 ) -> Rc<AppCell> {
198 let executor = platform.background_executor();
199 let foreground_executor = platform.foreground_executor();
200 assert!(
201 executor.is_main_thread(),
202 "must construct App on main thread"
203 );
204
205 let text_system = Arc::new(TextSystem::new(platform.text_system()));
206 let entities = EntityMap::new();
207
208 let app_metadata = AppMetadata {
209 os_name: platform.os_name(),
210 os_version: platform.os_version().ok(),
211 app_version: platform.app_version().ok(),
212 };
213
214 Rc::new_cyclic(|this| AppCell {
215 app: RefCell::new(AppContext {
216 this: this.clone(),
217 platform,
218 app_metadata,
219 text_system,
220 flushing_effects: false,
221 pending_updates: 0,
222 active_drag: None,
223 active_tooltip: None,
224 next_frame_callbacks: HashMap::default(),
225 frame_consumers: HashMap::default(),
226 background_executor: executor,
227 foreground_executor,
228 svg_renderer: SvgRenderer::new(asset_source.clone()),
229 asset_source,
230 image_cache: ImageCache::new(http_client),
231 text_style_stack: Vec::new(),
232 globals_by_type: HashMap::default(),
233 entities,
234 windows: SlotMap::with_key(),
235 keymap: Arc::new(Mutex::new(Keymap::default())),
236 global_action_listeners: HashMap::default(),
237 action_builders: HashMap::default(),
238 pending_effects: VecDeque::new(),
239 pending_notifications: HashSet::default(),
240 pending_global_notifications: HashSet::default(),
241 observers: SubscriberSet::new(),
242 event_listeners: SubscriberSet::new(),
243 release_listeners: SubscriberSet::new(),
244 global_observers: SubscriberSet::new(),
245 quit_observers: SubscriberSet::new(),
246 layout_id_buffer: Default::default(),
247 propagate_event: true,
248 }),
249 })
250 }
251
252 /// Quit the application gracefully. Handlers registered with `ModelContext::on_app_quit`
253 /// will be given 100ms to complete before exiting.
254 pub fn quit(&mut self) {
255 let mut futures = Vec::new();
256
257 for observer in self.quit_observers.remove(&()) {
258 futures.push(observer(self));
259 }
260
261 self.windows.clear();
262 self.flush_effects();
263
264 let futures = futures::future::join_all(futures);
265 if self
266 .background_executor
267 .block_with_timeout(Duration::from_millis(100), futures)
268 .is_err()
269 {
270 log::error!("timed out waiting on app_will_quit");
271 }
272
273 self.globals_by_type.clear();
274 }
275
276 pub fn app_metadata(&self) -> AppMetadata {
277 self.app_metadata.clone()
278 }
279
280 /// Schedules all windows in the application to be redrawn. This can be called
281 /// multiple times in an update cycle and still result in a single redraw.
282 pub fn refresh(&mut self) {
283 self.pending_effects.push_back(Effect::Refresh);
284 }
285 pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
286 self.pending_updates += 1;
287 let result = update(self);
288 if !self.flushing_effects && self.pending_updates == 1 {
289 self.flushing_effects = true;
290 self.flush_effects();
291 self.flushing_effects = false;
292 }
293 self.pending_updates -= 1;
294 result
295 }
296
297 pub fn windows(&self) -> Vec<AnyWindowHandle> {
298 self.windows
299 .values()
300 .filter_map(|window| Some(window.as_ref()?.handle.clone()))
301 .collect()
302 }
303
304 /// Opens a new window with the given option and the root view returned by the given function.
305 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
306 /// functionality.
307 pub fn open_window<V: Render>(
308 &mut self,
309 options: crate::WindowOptions,
310 build_root_view: impl FnOnce(&mut WindowContext) -> View<V>,
311 ) -> WindowHandle<V> {
312 self.update(|cx| {
313 let id = cx.windows.insert(None);
314 let handle = WindowHandle::new(id);
315 let mut window = Window::new(handle.into(), options, cx);
316 let root_view = build_root_view(&mut WindowContext::new(cx, &mut window));
317 window.root_view.replace(root_view.into());
318 cx.windows.get_mut(id).unwrap().replace(window);
319 handle
320 })
321 }
322
323 /// Instructs the platform to activate the application by bringing it to the foreground.
324 pub fn activate(&self, ignoring_other_apps: bool) {
325 self.platform.activate(ignoring_other_apps);
326 }
327
328 /// Returns the list of currently active displays.
329 pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
330 self.platform.displays()
331 }
332
333 /// Writes data to the platform clipboard.
334 pub fn write_to_clipboard(&self, item: ClipboardItem) {
335 self.platform.write_to_clipboard(item)
336 }
337
338 /// Reads data from the platform clipboard.
339 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
340 self.platform.read_from_clipboard()
341 }
342
343 /// Writes credentials to the platform keychain.
344 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
345 self.platform.write_credentials(url, username, password)
346 }
347
348 /// Reads credentials from the platform keychain.
349 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
350 self.platform.read_credentials(url)
351 }
352
353 /// Deletes credentials from the platform keychain.
354 pub fn delete_credentials(&self, url: &str) -> Result<()> {
355 self.platform.delete_credentials(url)
356 }
357
358 /// Directs the platform's default browser to open the given URL.
359 pub fn open_url(&self, url: &str) {
360 self.platform.open_url(url);
361 }
362
363 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
364 self.platform.path_for_auxiliary_executable(name)
365 }
366
367 pub fn prompt_for_paths(
368 &self,
369 options: PathPromptOptions,
370 ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
371 self.platform.prompt_for_paths(options)
372 }
373
374 pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
375 self.platform.prompt_for_new_path(directory)
376 }
377
378 pub fn reveal_path(&self, path: &Path) {
379 self.platform.reveal_path(path)
380 }
381
382 pub fn should_auto_hide_scrollbars(&self) -> bool {
383 self.platform.should_auto_hide_scrollbars()
384 }
385
386 pub(crate) fn push_effect(&mut self, effect: Effect) {
387 match &effect {
388 Effect::Notify { emitter } => {
389 if !self.pending_notifications.insert(*emitter) {
390 return;
391 }
392 }
393 Effect::NotifyGlobalObservers { global_type } => {
394 if !self.pending_global_notifications.insert(*global_type) {
395 return;
396 }
397 }
398 _ => {}
399 };
400
401 self.pending_effects.push_back(effect);
402 }
403
404 /// Called at the end of AppContext::update to complete any side effects
405 /// such as notifying observers, emitting events, etc. Effects can themselves
406 /// cause effects, so we continue looping until all effects are processed.
407 fn flush_effects(&mut self) {
408 loop {
409 self.release_dropped_entities();
410 self.release_dropped_focus_handles();
411 if let Some(effect) = self.pending_effects.pop_front() {
412 match effect {
413 Effect::Notify { emitter } => {
414 self.apply_notify_effect(emitter);
415 }
416 Effect::Emit { emitter, event } => self.apply_emit_effect(emitter, event),
417 Effect::FocusChanged {
418 window_handle,
419 focused,
420 } => {
421 self.apply_focus_changed_effect(window_handle, focused);
422 }
423 Effect::Refresh => {
424 self.apply_refresh_effect();
425 }
426 Effect::NotifyGlobalObservers { global_type } => {
427 self.apply_notify_global_observers_effect(global_type);
428 }
429 Effect::Defer { callback } => {
430 self.apply_defer_effect(callback);
431 }
432 }
433 } else {
434 break;
435 }
436 }
437
438 let dirty_window_ids = self
439 .windows
440 .iter()
441 .filter_map(|(_, window)| {
442 let window = window.as_ref().unwrap();
443 if window.dirty {
444 Some(window.handle.clone())
445 } else {
446 None
447 }
448 })
449 .collect::<SmallVec<[_; 8]>>();
450
451 for dirty_window_handle in dirty_window_ids {
452 dirty_window_handle.update(self, |_, cx| cx.draw()).unwrap();
453 }
454 }
455
456 /// Repeatedly called during `flush_effects` to release any entities whose
457 /// reference count has become zero. We invoke any release observers before dropping
458 /// each entity.
459 fn release_dropped_entities(&mut self) {
460 loop {
461 let dropped = self.entities.take_dropped();
462 if dropped.is_empty() {
463 break;
464 }
465
466 for (entity_id, mut entity) in dropped {
467 self.observers.remove(&entity_id);
468 self.event_listeners.remove(&entity_id);
469 for release_callback in self.release_listeners.remove(&entity_id) {
470 release_callback(entity.as_mut(), self);
471 }
472 }
473 }
474 }
475
476 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
477 /// For now, we simply blur the window if this happens, but we may want to support invoking
478 /// a window blur handler to restore focus to some logical element.
479 fn release_dropped_focus_handles(&mut self) {
480 for window_handle in self.windows() {
481 window_handle
482 .update(self, |_, cx| {
483 let mut blur_window = false;
484 let focus = cx.window.focus;
485 cx.window.focus_handles.write().retain(|handle_id, count| {
486 if count.load(SeqCst) == 0 {
487 if focus == Some(handle_id) {
488 blur_window = true;
489 }
490 false
491 } else {
492 true
493 }
494 });
495
496 if blur_window {
497 cx.blur();
498 }
499 })
500 .unwrap();
501 }
502 }
503
504 fn apply_notify_effect(&mut self, emitter: EntityId) {
505 self.pending_notifications.remove(&emitter);
506 self.observers
507 .clone()
508 .retain(&emitter, |handler| handler(self));
509 }
510
511 fn apply_emit_effect(&mut self, emitter: EntityId, event: Box<dyn Any>) {
512 self.event_listeners
513 .clone()
514 .retain(&emitter, |handler| handler(event.as_ref(), self));
515 }
516
517 fn apply_focus_changed_effect(
518 &mut self,
519 window_handle: AnyWindowHandle,
520 focused: Option<FocusId>,
521 ) {
522 window_handle
523 .update(self, |_, cx| {
524 if cx.window.focus == focused {
525 let mut listeners = mem::take(&mut cx.window.focus_listeners);
526 let focused = focused
527 .map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
528 let blurred = cx
529 .window
530 .last_blur
531 .take()
532 .unwrap()
533 .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
534 if focused.is_some() || blurred.is_some() {
535 let event = FocusEvent { focused, blurred };
536 for listener in &listeners {
537 listener(&event, cx);
538 }
539 }
540
541 listeners.extend(cx.window.focus_listeners.drain(..));
542 cx.window.focus_listeners = listeners;
543 }
544 })
545 .ok();
546 }
547
548 fn apply_refresh_effect(&mut self) {
549 for window in self.windows.values_mut() {
550 if let Some(window) = window.as_mut() {
551 window.dirty = true;
552 }
553 }
554 }
555
556 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
557 self.pending_global_notifications.remove(&type_id);
558 self.global_observers
559 .clone()
560 .retain(&type_id, |observer| observer(self));
561 }
562
563 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
564 callback(self);
565 }
566
567 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
568 /// so it can be held across `await` points.
569 pub fn to_async(&self) -> AsyncAppContext {
570 AsyncAppContext {
571 app: unsafe { mem::transmute(self.this.clone()) },
572 background_executor: self.background_executor.clone(),
573 foreground_executor: self.foreground_executor.clone(),
574 }
575 }
576
577 /// Obtains a reference to the executor, which can be used to spawn futures.
578 pub fn background_executor(&self) -> &BackgroundExecutor {
579 &self.background_executor
580 }
581
582 /// Obtains a reference to the executor, which can be used to spawn futures.
583 pub fn foreground_executor(&self) -> &ForegroundExecutor {
584 &self.foreground_executor
585 }
586
587 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
588 /// with AsyncAppContext, which allows the application state to be accessed across await points.
589 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
590 where
591 Fut: Future<Output = R> + 'static,
592 R: 'static,
593 {
594 self.foreground_executor.spawn(f(self.to_async()))
595 }
596
597 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
598 /// that are currently on the stack to be returned to the app.
599 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
600 self.push_effect(Effect::Defer {
601 callback: Box::new(f),
602 });
603 }
604
605 /// Accessor for the application's asset source, which is provided when constructing the `App`.
606 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
607 &self.asset_source
608 }
609
610 /// Accessor for the text system.
611 pub fn text_system(&self) -> &Arc<TextSystem> {
612 &self.text_system
613 }
614
615 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
616 pub fn text_style(&self) -> TextStyle {
617 let mut style = TextStyle::default();
618 for refinement in &self.text_style_stack {
619 style.refine(refinement);
620 }
621 style
622 }
623
624 /// Check whether a global of the given type has been assigned.
625 pub fn has_global<G: 'static>(&self) -> bool {
626 self.globals_by_type.contains_key(&TypeId::of::<G>())
627 }
628
629 /// Access the global of the given type. Panics if a global for that type has not been assigned.
630 pub fn global<G: 'static>(&self) -> &G {
631 self.globals_by_type
632 .get(&TypeId::of::<G>())
633 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
634 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
635 .unwrap()
636 }
637
638 /// Access the global of the given type if a value has been assigned.
639 pub fn try_global<G: 'static>(&self) -> Option<&G> {
640 self.globals_by_type
641 .get(&TypeId::of::<G>())
642 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
643 }
644
645 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
646 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
647 let global_type = TypeId::of::<G>();
648 self.push_effect(Effect::NotifyGlobalObservers { global_type });
649 self.globals_by_type
650 .get_mut(&global_type)
651 .and_then(|any_state| any_state.downcast_mut::<G>())
652 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
653 .unwrap()
654 }
655
656 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
657 /// yet been assigned.
658 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
659 let global_type = TypeId::of::<G>();
660 self.push_effect(Effect::NotifyGlobalObservers { global_type });
661 self.globals_by_type
662 .entry(global_type)
663 .or_insert_with(|| Box::new(G::default()))
664 .downcast_mut::<G>()
665 .unwrap()
666 }
667
668 /// Set the value of the global of the given type.
669 pub fn set_global<G: Any>(&mut self, global: G) {
670 let global_type = TypeId::of::<G>();
671 self.push_effect(Effect::NotifyGlobalObservers { global_type });
672 self.globals_by_type.insert(global_type, Box::new(global));
673 }
674
675 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
676 /// your closure with mutable access to the `AppContext` and the global simultaneously.
677 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
678 let mut global = self.lease_global::<G>();
679 let result = f(&mut global, self);
680 self.end_global_lease(global);
681 result
682 }
683
684 /// Register a callback to be invoked when a global of the given type is updated.
685 pub fn observe_global<G: 'static>(
686 &mut self,
687 mut f: impl FnMut(&mut Self) + 'static,
688 ) -> Subscription {
689 self.global_observers.insert(
690 TypeId::of::<G>(),
691 Box::new(move |cx| {
692 f(cx);
693 true
694 }),
695 )
696 }
697
698 pub fn all_action_names<'a>(&'a self) -> impl Iterator<Item = SharedString> + 'a {
699 self.action_builders.keys().cloned()
700 }
701
702 /// Move the global of the given type to the stack.
703 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
704 GlobalLease::new(
705 self.globals_by_type
706 .remove(&TypeId::of::<G>())
707 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
708 .unwrap(),
709 )
710 }
711
712 /// Restore the global of the given type after it is moved to the stack.
713 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
714 let global_type = TypeId::of::<G>();
715 self.push_effect(Effect::NotifyGlobalObservers { global_type });
716 self.globals_by_type.insert(global_type, lease.global);
717 }
718
719 pub fn observe_release<E, T>(
720 &mut self,
721 handle: &E,
722 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
723 ) -> Subscription
724 where
725 E: Entity<T>,
726 T: 'static,
727 {
728 self.release_listeners.insert(
729 handle.entity_id(),
730 Box::new(move |entity, cx| {
731 let entity = entity.downcast_mut().expect("invalid entity type");
732 on_release(entity, cx)
733 }),
734 )
735 }
736
737 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
738 self.text_style_stack.push(text_style);
739 }
740
741 pub(crate) fn pop_text_style(&mut self) {
742 self.text_style_stack.pop();
743 }
744
745 /// Register key bindings.
746 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
747 self.keymap.lock().add_bindings(bindings);
748 self.pending_effects.push_back(Effect::Refresh);
749 }
750
751 /// Register a global listener for actions invoked via the keyboard.
752 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
753 self.global_action_listeners
754 .entry(TypeId::of::<A>())
755 .or_default()
756 .push(Box::new(move |action, phase, cx| {
757 if phase == DispatchPhase::Bubble {
758 let action = action.as_any().downcast_ref().unwrap();
759 listener(action, cx)
760 }
761 }));
762 }
763
764 /// Register an action type to allow it to be referenced in keymaps.
765 pub fn register_action_type<A: Action>(&mut self) {
766 self.action_builders.insert(A::qualified_name(), A::build);
767 }
768
769 /// Construct an action based on its name and parameters.
770 pub fn build_action(
771 &mut self,
772 name: &str,
773 params: Option<serde_json::Value>,
774 ) -> Result<Box<dyn Action>> {
775 let build = self
776 .action_builders
777 .get(name)
778 .ok_or_else(|| anyhow!("no action type registered for {}", name))?;
779 (build)(params)
780 }
781
782 /// Event handlers propagate events by default. Call this method to stop dispatching to
783 /// event handlers with a lower z-index (mouse) or higher in the tree (keyboard). This is
784 /// the opposite of [propagate]. It's also possible to cancel a call to [propagate] by
785 /// calling this method before effects are flushed.
786 pub fn stop_propagation(&mut self) {
787 self.propagate_event = false;
788 }
789
790 /// Action handlers stop propagation by default during the bubble phase of action dispatch
791 /// dispatching to action handlers higher in the element tree. This is the opposite of
792 /// [stop_propagation]. It's also possible to cancel a call to [stop_propagate] by calling
793 /// this method before effects are flushed.
794 pub fn propagate(&mut self) {
795 self.propagate_event = true;
796 }
797}
798
799impl Context for AppContext {
800 type Result<T> = T;
801
802 /// Build an entity that is owned by the application. The given function will be invoked with
803 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
804 /// which can be used to access the entity in a context.
805 fn build_model<T: 'static>(
806 &mut self,
807 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
808 ) -> Model<T> {
809 self.update(|cx| {
810 let slot = cx.entities.reserve();
811 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
812 cx.entities.insert(slot, entity)
813 })
814 }
815
816 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
817 /// entity along with a `ModelContext` for the entity.
818 fn update_model<T: 'static, R>(
819 &mut self,
820 model: &Model<T>,
821 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
822 ) -> R {
823 self.update(|cx| {
824 let mut entity = cx.entities.lease(model);
825 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
826 cx.entities.end_lease(entity);
827 result
828 })
829 }
830
831 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
832 where
833 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
834 {
835 self.update(|cx| {
836 let mut window = cx
837 .windows
838 .get_mut(handle.id)
839 .ok_or_else(|| anyhow!("window not found"))?
840 .take()
841 .unwrap();
842
843 let root_view = window.root_view.clone().unwrap();
844 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
845
846 if !window.removed {
847 cx.windows
848 .get_mut(handle.id)
849 .ok_or_else(|| anyhow!("window not found"))?
850 .replace(window);
851 }
852
853 Ok(result)
854 })
855 }
856}
857
858/// These effects are processed at the end of each application update cycle.
859pub(crate) enum Effect {
860 Notify {
861 emitter: EntityId,
862 },
863 Emit {
864 emitter: EntityId,
865 event: Box<dyn Any>,
866 },
867 FocusChanged {
868 window_handle: AnyWindowHandle,
869 focused: Option<FocusId>,
870 },
871 Refresh,
872 NotifyGlobalObservers {
873 global_type: TypeId,
874 },
875 Defer {
876 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
877 },
878}
879
880/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
881pub(crate) struct GlobalLease<G: 'static> {
882 global: AnyBox,
883 global_type: PhantomData<G>,
884}
885
886impl<G: 'static> GlobalLease<G> {
887 fn new(global: AnyBox) -> Self {
888 GlobalLease {
889 global,
890 global_type: PhantomData,
891 }
892 }
893}
894
895impl<G: 'static> Deref for GlobalLease<G> {
896 type Target = G;
897
898 fn deref(&self) -> &Self::Target {
899 self.global.downcast_ref().unwrap()
900 }
901}
902
903impl<G: 'static> DerefMut for GlobalLease<G> {
904 fn deref_mut(&mut self) -> &mut Self::Target {
905 self.global.downcast_mut().unwrap()
906 }
907}
908
909/// Contains state associated with an active drag operation, started by dragging an element
910/// within the window or by dragging into the app from the underlying platform.
911pub(crate) struct AnyDrag {
912 pub view: AnyView,
913 pub cursor_offset: Point<Pixels>,
914}
915
916#[derive(Clone)]
917pub(crate) struct AnyTooltip {
918 pub view: AnyView,
919 pub cursor_offset: Point<Pixels>,
920}