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