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