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 PathPromptOptions, Pixels, Platform, PlatformDisplay, Point, Render, SharedString,
20 SubscriberSet, Subscription, SvgRenderer, Task, TextStyle, TextStyleRefinement, TextSystem,
21 View, Window, WindowContext, WindowHandle, WindowId,
22};
23use anyhow::{anyhow, Result};
24use collections::{HashMap, HashSet, VecDeque};
25use futures::{channel::oneshot, 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::{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 /// Opens a new window with the given option and the root view returned by the given function.
266 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
267 /// functionality.
268 pub fn open_window<V: Render>(
269 &mut self,
270 options: crate::WindowOptions,
271 build_root_view: impl FnOnce(&mut WindowContext) -> View<V>,
272 ) -> WindowHandle<V> {
273 self.update(|cx| {
274 let id = cx.windows.insert(None);
275 let handle = WindowHandle::new(id);
276 let mut window = Window::new(handle.into(), options, cx);
277 let root_view = build_root_view(&mut WindowContext::new(cx, &mut window));
278 window.root_view.replace(root_view.into());
279 cx.windows.get_mut(id).unwrap().replace(window);
280 handle
281 })
282 }
283
284 /// Instructs the platform to activate the application by bringing it to the foreground.
285 pub fn activate(&self, ignoring_other_apps: bool) {
286 self.platform.activate(ignoring_other_apps);
287 }
288
289 /// Returns the list of currently active displays.
290 pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
291 self.platform.displays()
292 }
293
294 /// Writes data to the platform clipboard.
295 pub fn write_to_clipboard(&self, item: ClipboardItem) {
296 self.platform.write_to_clipboard(item)
297 }
298
299 /// Reads data from the platform clipboard.
300 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
301 self.platform.read_from_clipboard()
302 }
303
304 /// Writes credentials to the platform keychain.
305 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
306 self.platform.write_credentials(url, username, password)
307 }
308
309 /// Reads credentials from the platform keychain.
310 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
311 self.platform.read_credentials(url)
312 }
313
314 /// Deletes credentials from the platform keychain.
315 pub fn delete_credentials(&self, url: &str) -> Result<()> {
316 self.platform.delete_credentials(url)
317 }
318
319 /// Directs the platform's default browser to open the given URL.
320 pub fn open_url(&self, url: &str) {
321 self.platform.open_url(url);
322 }
323
324 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
325 self.platform.path_for_auxiliary_executable(name)
326 }
327
328 pub fn prompt_for_paths(
329 &self,
330 options: PathPromptOptions,
331 ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
332 self.platform.prompt_for_paths(options)
333 }
334
335 pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
336 self.platform.prompt_for_new_path(directory)
337 }
338
339 pub fn reveal_path(&self, path: &Path) {
340 self.platform.reveal_path(path)
341 }
342
343 pub(crate) fn push_effect(&mut self, effect: Effect) {
344 match &effect {
345 Effect::Notify { emitter } => {
346 if !self.pending_notifications.insert(*emitter) {
347 return;
348 }
349 }
350 Effect::NotifyGlobalObservers { global_type } => {
351 if !self.pending_global_notifications.insert(*global_type) {
352 return;
353 }
354 }
355 _ => {}
356 };
357
358 self.pending_effects.push_back(effect);
359 }
360
361 /// Called at the end of AppContext::update to complete any side effects
362 /// such as notifying observers, emitting events, etc. Effects can themselves
363 /// cause effects, so we continue looping until all effects are processed.
364 fn flush_effects(&mut self) {
365 loop {
366 self.release_dropped_entities();
367 self.release_dropped_focus_handles();
368 if let Some(effect) = self.pending_effects.pop_front() {
369 match effect {
370 Effect::Notify { emitter } => {
371 self.apply_notify_effect(emitter);
372 }
373 Effect::Emit { emitter, event } => self.apply_emit_effect(emitter, event),
374 Effect::FocusChanged {
375 window_handle,
376 focused,
377 } => {
378 self.apply_focus_changed_effect(window_handle, focused);
379 }
380 Effect::Refresh => {
381 self.apply_refresh_effect();
382 }
383 Effect::NotifyGlobalObservers { global_type } => {
384 self.apply_notify_global_observers_effect(global_type);
385 }
386 Effect::Defer { callback } => {
387 self.apply_defer_effect(callback);
388 }
389 }
390 } else {
391 break;
392 }
393 }
394
395 let dirty_window_ids = self
396 .windows
397 .iter()
398 .filter_map(|(_, window)| {
399 let window = window.as_ref().unwrap();
400 if window.dirty {
401 Some(window.handle.clone())
402 } else {
403 None
404 }
405 })
406 .collect::<SmallVec<[_; 8]>>();
407
408 for dirty_window_handle in dirty_window_ids {
409 dirty_window_handle.update(self, |_, cx| cx.draw()).unwrap();
410 }
411 }
412
413 /// Repeatedly called during `flush_effects` to release any entities whose
414 /// reference count has become zero. We invoke any release observers before dropping
415 /// each entity.
416 fn release_dropped_entities(&mut self) {
417 loop {
418 let dropped = self.entities.take_dropped();
419 if dropped.is_empty() {
420 break;
421 }
422
423 for (entity_id, mut entity) in dropped {
424 self.observers.remove(&entity_id);
425 self.event_listeners.remove(&entity_id);
426 for release_callback in self.release_listeners.remove(&entity_id) {
427 release_callback(entity.as_mut(), self);
428 }
429 }
430 }
431 }
432
433 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
434 /// For now, we simply blur the window if this happens, but we may want to support invoking
435 /// a window blur handler to restore focus to some logical element.
436 fn release_dropped_focus_handles(&mut self) {
437 for window_handle in self.windows() {
438 window_handle
439 .update(self, |_, cx| {
440 let mut blur_window = false;
441 let focus = cx.window.focus;
442 cx.window.focus_handles.write().retain(|handle_id, count| {
443 if count.load(SeqCst) == 0 {
444 if focus == Some(handle_id) {
445 blur_window = true;
446 }
447 false
448 } else {
449 true
450 }
451 });
452
453 if blur_window {
454 cx.blur();
455 }
456 })
457 .unwrap();
458 }
459 }
460
461 fn apply_notify_effect(&mut self, emitter: EntityId) {
462 self.pending_notifications.remove(&emitter);
463 self.observers
464 .clone()
465 .retain(&emitter, |handler| handler(self));
466 }
467
468 fn apply_emit_effect(&mut self, emitter: EntityId, event: Box<dyn Any>) {
469 self.event_listeners
470 .clone()
471 .retain(&emitter, |handler| handler(event.as_ref(), self));
472 }
473
474 fn apply_focus_changed_effect(
475 &mut self,
476 window_handle: AnyWindowHandle,
477 focused: Option<FocusId>,
478 ) {
479 window_handle
480 .update(self, |_, cx| {
481 if cx.window.focus == focused {
482 let mut listeners = mem::take(&mut cx.window.focus_listeners);
483 let focused = focused
484 .map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
485 let blurred = cx
486 .window
487 .last_blur
488 .take()
489 .unwrap()
490 .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
491 if focused.is_some() || blurred.is_some() {
492 let event = FocusEvent { focused, blurred };
493 for listener in &listeners {
494 listener(&event, cx);
495 }
496 }
497
498 listeners.extend(cx.window.focus_listeners.drain(..));
499 cx.window.focus_listeners = listeners;
500 }
501 })
502 .ok();
503 }
504
505 fn apply_refresh_effect(&mut self) {
506 for window in self.windows.values_mut() {
507 if let Some(window) = window.as_mut() {
508 window.dirty = true;
509 }
510 }
511 }
512
513 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
514 self.pending_global_notifications.remove(&type_id);
515 self.global_observers
516 .clone()
517 .retain(&type_id, |observer| observer(self));
518 }
519
520 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
521 callback(self);
522 }
523
524 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
525 /// so it can be held across `await` points.
526 pub fn to_async(&self) -> AsyncAppContext {
527 AsyncAppContext {
528 app: unsafe { mem::transmute(self.this.clone()) },
529 background_executor: self.background_executor.clone(),
530 foreground_executor: self.foreground_executor.clone(),
531 }
532 }
533
534 /// Obtains a reference to the executor, which can be used to spawn futures.
535 pub fn background_executor(&self) -> &BackgroundExecutor {
536 &self.background_executor
537 }
538
539 /// Obtains a reference to the executor, which can be used to spawn futures.
540 pub fn foreground_executor(&self) -> &ForegroundExecutor {
541 &self.foreground_executor
542 }
543
544 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
545 /// with AsyncAppContext, which allows the application state to be accessed across await points.
546 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
547 where
548 Fut: Future<Output = R> + 'static,
549 R: 'static,
550 {
551 self.foreground_executor.spawn(f(self.to_async()))
552 }
553
554 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
555 /// that are currently on the stack to be returned to the app.
556 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
557 self.push_effect(Effect::Defer {
558 callback: Box::new(f),
559 });
560 }
561
562 /// Accessor for the application's asset source, which is provided when constructing the `App`.
563 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
564 &self.asset_source
565 }
566
567 /// Accessor for the text system.
568 pub fn text_system(&self) -> &Arc<TextSystem> {
569 &self.text_system
570 }
571
572 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
573 pub fn text_style(&self) -> TextStyle {
574 let mut style = TextStyle::default();
575 for refinement in &self.text_style_stack {
576 style.refine(refinement);
577 }
578 style
579 }
580
581 /// Check whether a global of the given type has been assigned.
582 pub fn has_global<G: 'static>(&self) -> bool {
583 self.globals_by_type.contains_key(&TypeId::of::<G>())
584 }
585
586 /// Access the global of the given type. Panics if a global for that type has not been assigned.
587 pub fn global<G: 'static>(&self) -> &G {
588 self.globals_by_type
589 .get(&TypeId::of::<G>())
590 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
591 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
592 .unwrap()
593 }
594
595 /// Access the global of the given type if a value has been assigned.
596 pub fn try_global<G: 'static>(&self) -> Option<&G> {
597 self.globals_by_type
598 .get(&TypeId::of::<G>())
599 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
600 }
601
602 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
603 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
604 let global_type = TypeId::of::<G>();
605 self.push_effect(Effect::NotifyGlobalObservers { global_type });
606 self.globals_by_type
607 .get_mut(&global_type)
608 .and_then(|any_state| any_state.downcast_mut::<G>())
609 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
610 .unwrap()
611 }
612
613 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
614 /// yet been assigned.
615 pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
616 let global_type = TypeId::of::<G>();
617 self.push_effect(Effect::NotifyGlobalObservers { global_type });
618 self.globals_by_type
619 .entry(global_type)
620 .or_insert_with(|| Box::new(G::default()))
621 .downcast_mut::<G>()
622 .unwrap()
623 }
624
625 /// Set the value of the global of the given type.
626 pub fn set_global<G: Any>(&mut self, global: G) {
627 let global_type = TypeId::of::<G>();
628 self.push_effect(Effect::NotifyGlobalObservers { global_type });
629 self.globals_by_type.insert(global_type, Box::new(global));
630 }
631
632 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
633 /// your closure with mutable access to the `AppContext` and the global simultaneously.
634 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
635 let mut global = self.lease_global::<G>();
636 let result = f(&mut global, self);
637 self.end_global_lease(global);
638 result
639 }
640
641 /// Register a callback to be invoked when a global of the given type is updated.
642 pub fn observe_global<G: 'static>(
643 &mut self,
644 mut f: impl FnMut(&mut Self) + 'static,
645 ) -> Subscription {
646 self.global_observers.insert(
647 TypeId::of::<G>(),
648 Box::new(move |cx| {
649 f(cx);
650 true
651 }),
652 )
653 }
654
655 pub fn all_action_names<'a>(&'a self) -> impl Iterator<Item = SharedString> + 'a {
656 self.action_builders.keys().cloned()
657 }
658
659 /// Move the global of the given type to the stack.
660 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
661 GlobalLease::new(
662 self.globals_by_type
663 .remove(&TypeId::of::<G>())
664 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
665 .unwrap(),
666 )
667 }
668
669 /// Restore the global of the given type after it is moved to the stack.
670 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
671 let global_type = TypeId::of::<G>();
672 self.push_effect(Effect::NotifyGlobalObservers { global_type });
673 self.globals_by_type.insert(global_type, lease.global);
674 }
675
676 pub fn observe_release<E, T>(
677 &mut self,
678 handle: &E,
679 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
680 ) -> Subscription
681 where
682 E: Entity<T>,
683 T: 'static,
684 {
685 self.release_listeners.insert(
686 handle.entity_id(),
687 Box::new(move |entity, cx| {
688 let entity = entity.downcast_mut().expect("invalid entity type");
689 on_release(entity, cx)
690 }),
691 )
692 }
693
694 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
695 self.text_style_stack.push(text_style);
696 }
697
698 pub(crate) fn pop_text_style(&mut self) {
699 self.text_style_stack.pop();
700 }
701
702 /// Register key bindings.
703 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
704 self.keymap.lock().add_bindings(bindings);
705 self.pending_effects.push_back(Effect::Refresh);
706 }
707
708 /// Register a global listener for actions invoked via the keyboard.
709 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
710 self.global_action_listeners
711 .entry(TypeId::of::<A>())
712 .or_default()
713 .push(Box::new(move |action, phase, cx| {
714 if phase == DispatchPhase::Bubble {
715 let action = action.as_any().downcast_ref().unwrap();
716 listener(action, cx)
717 }
718 }));
719 }
720
721 /// Register an action type to allow it to be referenced in keymaps.
722 pub fn register_action_type<A: Action>(&mut self) {
723 self.action_builders.insert(A::qualified_name(), A::build);
724 }
725
726 /// Construct an action based on its name and parameters.
727 pub fn build_action(
728 &mut self,
729 name: &str,
730 params: Option<serde_json::Value>,
731 ) -> Result<Box<dyn Action>> {
732 let build = self
733 .action_builders
734 .get(name)
735 .ok_or_else(|| anyhow!("no action type registered for {}", name))?;
736 (build)(params)
737 }
738
739 /// Halt propagation of a mouse event, keyboard event, or action. This prevents listeners
740 /// that have not yet been invoked from receiving the event.
741 pub fn stop_propagation(&mut self) {
742 self.propagate_event = false;
743 }
744}
745
746impl Context for AppContext {
747 type Result<T> = T;
748
749 /// Build an entity that is owned by the application. The given function will be invoked with
750 /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
751 /// which can be used to access the entity in a context.
752 fn build_model<T: 'static>(
753 &mut self,
754 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
755 ) -> Model<T> {
756 self.update(|cx| {
757 let slot = cx.entities.reserve();
758 let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
759 cx.entities.insert(slot, entity)
760 })
761 }
762
763 /// Update the entity referenced by the given model. The function is passed a mutable reference to the
764 /// entity along with a `ModelContext` for the entity.
765 fn update_model<T: 'static, R>(
766 &mut self,
767 model: &Model<T>,
768 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
769 ) -> R {
770 self.update(|cx| {
771 let mut entity = cx.entities.lease(model);
772 let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
773 cx.entities.end_lease(entity);
774 result
775 })
776 }
777
778 fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
779 where
780 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
781 {
782 self.update(|cx| {
783 let mut window = cx
784 .windows
785 .get_mut(handle.id)
786 .ok_or_else(|| anyhow!("window not found"))?
787 .take()
788 .unwrap();
789
790 let root_view = window.root_view.clone().unwrap();
791 let result = update(root_view, &mut WindowContext::new(cx, &mut window));
792 cx.windows
793 .get_mut(handle.id)
794 .ok_or_else(|| anyhow!("window not found"))?
795 .replace(window);
796
797 Ok(result)
798 })
799 }
800}
801
802/// These effects are processed at the end of each application update cycle.
803pub(crate) enum Effect {
804 Notify {
805 emitter: EntityId,
806 },
807 Emit {
808 emitter: EntityId,
809 event: Box<dyn Any>,
810 },
811 FocusChanged {
812 window_handle: AnyWindowHandle,
813 focused: Option<FocusId>,
814 },
815 Refresh,
816 NotifyGlobalObservers {
817 global_type: TypeId,
818 },
819 Defer {
820 callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
821 },
822}
823
824/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
825pub(crate) struct GlobalLease<G: 'static> {
826 global: AnyBox,
827 global_type: PhantomData<G>,
828}
829
830impl<G: 'static> GlobalLease<G> {
831 fn new(global: AnyBox) -> Self {
832 GlobalLease {
833 global,
834 global_type: PhantomData,
835 }
836 }
837}
838
839impl<G: 'static> Deref for GlobalLease<G> {
840 type Target = G;
841
842 fn deref(&self) -> &Self::Target {
843 self.global.downcast_ref().unwrap()
844 }
845}
846
847impl<G: 'static> DerefMut for GlobalLease<G> {
848 fn deref_mut(&mut self) -> &mut Self::Target {
849 self.global.downcast_mut().unwrap()
850 }
851}
852
853/// Contains state associated with an active drag operation, started by dragging an element
854/// within the window or by dragging into the app from the underlying platform.
855pub(crate) struct AnyDrag {
856 pub view: AnyView,
857 pub cursor_offset: Point<Pixels>,
858}