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, ClipboardItem, Context, DispatchPhase, DisplayId, Executor,
18 FocusEvent, FocusHandle, FocusId, KeyBinding, Keymap, LayoutId, MainThread, MainThreadOnly,
19 Pixels, Platform, Point, SharedString, SubscriberSet, Subscription, SvgRenderer, Task,
20 TextStyle, TextStyleRefinement, TextSystem, View, ViewContext, Window, WindowContext,
21 WindowHandle, WindowId,
22};
23use anyhow::{anyhow, Result};
24use collections::{HashMap, HashSet, VecDeque};
25use futures::{future::BoxFuture, Future};
26use parking_lot::Mutex;
27use slotmap::SlotMap;
28use std::{
29 any::{type_name, Any, TypeId},
30 borrow::Borrow,
31 marker::PhantomData,
32 mem,
33 ops::{Deref, DerefMut},
34 path::PathBuf,
35 sync::{atomic::Ordering::SeqCst, Arc, Weak},
36 time::Duration,
37};
38use util::http::{self, HttpClient};
39
40pub struct App(Arc<Mutex<AppContext>>);
41
42/// Represents an application before it is fully launched. Once your app is
43/// configured, you'll start the app with `App::run`.
44impl App {
45 /// Builds an app with the given asset source.
46 pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
47 Self(AppContext::new(
48 current_platform(),
49 asset_source,
50 http::client(),
51 ))
52 }
53
54 /// Start the application. The provided callback will be called once the
55 /// app is fully launched.
56 pub fn run<F>(self, on_finish_launching: F)
57 where
58 F: 'static + FnOnce(&mut MainThread<AppContext>),
59 {
60 let this = self.0.clone();
61 let platform = self.0.lock().platform.clone();
62 platform.borrow_on_main_thread().run(Box::new(move || {
63 let cx = &mut *this.lock();
64 let cx = unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) };
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 = Arc::downgrade(&self.0);
76 self.0
77 .lock()
78 .platform
79 .borrow_on_main_thread()
80 .on_open_urls(Box::new(move |urls| {
81 if let Some(app) = this.upgrade() {
82 callback(urls, &mut app.lock());
83 }
84 }));
85 self
86 }
87
88 pub fn on_reopen<F>(&self, mut callback: F) -> &Self
89 where
90 F: 'static + FnMut(&mut AppContext),
91 {
92 let this = Arc::downgrade(&self.0);
93 self.0
94 .lock()
95 .platform
96 .borrow_on_main_thread()
97 .on_reopen(Box::new(move || {
98 if let Some(app) = this.upgrade() {
99 callback(&mut app.lock());
100 }
101 }));
102 self
103 }
104
105 pub fn metadata(&self) -> AppMetadata {
106 self.0.lock().app_metadata.clone()
107 }
108
109 pub fn executor(&self) -> Executor {
110 self.0.lock().executor.clone()
111 }
112
113 pub fn text_system(&self) -> Arc<TextSystem> {
114 self.0.lock().text_system.clone()
115 }
116}
117
118type ActionBuilder = fn(json: Option<serde_json::Value>) -> anyhow::Result<Box<dyn Action>>;
119type FrameCallback = Box<dyn FnOnce(&mut WindowContext) + Send>;
120type Handler = Box<dyn FnMut(&mut AppContext) -> bool + Send + 'static>;
121type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + Send + 'static>;
122type QuitHandler = Box<dyn FnMut(&mut AppContext) -> BoxFuture<'static, ()> + Send + 'static>;
123type ReleaseListener = Box<dyn FnMut(&mut dyn Any, &mut AppContext) + Send + 'static>;
124
125pub struct AppContext {
126 this: Weak<Mutex<AppContext>>,
127 pub(crate) platform: MainThreadOnly<dyn Platform>,
128 app_metadata: AppMetadata,
129 text_system: Arc<TextSystem>,
130 flushing_effects: bool,
131 pending_updates: usize,
132 pub(crate) active_drag: Option<AnyDrag>,
133 pub(crate) next_frame_callbacks: HashMap<DisplayId, Vec<FrameCallback>>,
134 pub(crate) executor: Executor,
135 pub(crate) svg_renderer: SvgRenderer,
136 asset_source: Arc<dyn AssetSource>,
137 pub(crate) image_cache: ImageCache,
138 pub(crate) text_style_stack: Vec<TextStyleRefinement>,
139 pub(crate) globals_by_type: HashMap<TypeId, AnyBox>,
140 pub(crate) entities: EntityMap,
141 pub(crate) windows: SlotMap<WindowId, Option<Window>>,
142 pub(crate) keymap: Arc<Mutex<Keymap>>,
143 pub(crate) global_action_listeners:
144 HashMap<TypeId, Vec<Box<dyn Fn(&dyn Action, DispatchPhase, &mut Self) + Send>>>,
145 action_builders: HashMap<SharedString, ActionBuilder>,
146 pending_effects: VecDeque<Effect>,
147 pub(crate) pending_notifications: HashSet<EntityId>,
148 pub(crate) pending_global_notifications: HashSet<TypeId>,
149 pub(crate) observers: SubscriberSet<EntityId, Handler>,
150 pub(crate) event_listeners: SubscriberSet<EntityId, Listener>,
151 pub(crate) release_listeners: SubscriberSet<EntityId, ReleaseListener>,
152 pub(crate) global_observers: SubscriberSet<TypeId, Handler>,
153 pub(crate) quit_observers: SubscriberSet<(), QuitHandler>,
154 pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
155 pub(crate) propagate_event: bool,
156}
157
158impl AppContext {
159 pub(crate) fn new(
160 platform: Arc<dyn Platform>,
161 asset_source: Arc<dyn AssetSource>,
162 http_client: Arc<dyn HttpClient>,
163 ) -> Arc<Mutex<Self>> {
164 let executor = platform.executor();
165 assert!(
166 executor.is_main_thread(),
167 "must construct App on main thread"
168 );
169
170 let text_system = Arc::new(TextSystem::new(platform.text_system()));
171 let entities = EntityMap::new();
172
173 let app_metadata = AppMetadata {
174 os_name: platform.os_name(),
175 os_version: platform.os_version().ok(),
176 app_version: platform.app_version().ok(),
177 };
178
179 Arc::new_cyclic(|this| {
180 Mutex::new(AppContext {
181 this: this.clone(),
182 text_system,
183 platform: MainThreadOnly::new(platform, executor.clone()),
184 app_metadata,
185 flushing_effects: false,
186 pending_updates: 0,
187 next_frame_callbacks: Default::default(),
188 executor,
189 svg_renderer: SvgRenderer::new(asset_source.clone()),
190 asset_source,
191 image_cache: ImageCache::new(http_client),
192 text_style_stack: Vec::new(),
193 globals_by_type: HashMap::default(),
194 entities,
195 windows: SlotMap::with_key(),
196 keymap: Arc::new(Mutex::new(Keymap::default())),
197 global_action_listeners: HashMap::default(),
198 action_builders: HashMap::default(),
199 pending_effects: VecDeque::new(),
200 pending_notifications: HashSet::default(),
201 pending_global_notifications: HashSet::default(),
202 observers: SubscriberSet::new(),
203 event_listeners: SubscriberSet::new(),
204 release_listeners: SubscriberSet::new(),
205 global_observers: SubscriberSet::new(),
206 quit_observers: SubscriberSet::new(),
207 layout_id_buffer: Default::default(),
208 propagate_event: true,
209 active_drag: None,
210 })
211 })
212 }
213
214 /// Quit the application gracefully. Handlers registered with `ModelContext::on_app_quit`
215 /// will be given 100ms to complete before exiting.
216 pub fn quit(&mut self) {
217 let mut futures = Vec::new();
218
219 self.quit_observers.clone().retain(&(), |observer| {
220 futures.push(observer(self));
221 true
222 });
223
224 self.windows.clear();
225 self.flush_effects();
226
227 let futures = futures::future::join_all(futures);
228 if self
229 .executor
230 .block_with_timeout(Duration::from_millis(100), futures)
231 .is_err()
232 {
233 log::error!("timed out waiting on app_will_quit");
234 }
235
236 self.globals_by_type.clear();
237 }
238
239 pub fn app_metadata(&self) -> AppMetadata {
240 self.app_metadata.clone()
241 }
242
243 /// Schedules all windows in the application to be redrawn. This can be called
244 /// multiple times in an update cycle and still result in a single redraw.
245 pub fn refresh(&mut self) {
246 self.pending_effects.push_back(Effect::Refresh);
247 }
248
249 pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
250 self.pending_updates += 1;
251 let result = update(self);
252 if !self.flushing_effects && self.pending_updates == 1 {
253 self.flushing_effects = true;
254 self.flush_effects();
255 self.flushing_effects = false;
256 }
257 self.pending_updates -= 1;
258 result
259 }
260
261 pub fn windows(&self) -> Vec<AnyWindowHandle> {
262 self.windows
263 .values()
264 .filter_map(|window| Some(window.as_ref()?.handle.clone()))
265 .collect()
266 }
267
268 pub(crate) fn read_window<R>(
269 &mut self,
270 handle: AnyWindowHandle,
271 read: impl FnOnce(&WindowContext) -> R,
272 ) -> Result<R> {
273 let window = self
274 .windows
275 .get(handle.id)
276 .ok_or_else(|| anyhow!("window not found"))?
277 .as_ref()
278 .unwrap();
279 Ok(read(&WindowContext::immutable(self, &window)))
280 }
281
282 pub(crate) fn update_window<R>(
283 &mut self,
284 handle: AnyWindowHandle,
285 update: impl FnOnce(&mut WindowContext) -> R,
286 ) -> Result<R> {
287 self.update(|cx| {
288 let mut window = cx
289 .windows
290 .get_mut(handle.id)
291 .ok_or_else(|| anyhow!("window not found"))?
292 .take()
293 .unwrap();
294
295 let result = update(&mut WindowContext::mutable(cx, &mut window));
296
297 cx.windows
298 .get_mut(handle.id)
299 .ok_or_else(|| anyhow!("window not found"))?
300 .replace(window);
301
302 Ok(result)
303 })
304 }
305
306 pub fn update_window_root<V, R>(
307 &mut self,
308 handle: &WindowHandle<V>,
309 update: impl FnOnce(&mut V, &mut ViewContext<'_, '_, V>) -> R,
310 ) -> Result<R>
311 where
312 V: 'static,
313 {
314 self.update_window(handle.any_handle, |cx| {
315 let root_view = cx.window.root_view.as_ref().unwrap().downcast().unwrap();
316 root_view.update(cx, update)
317 })
318 }
319
320 pub(crate) fn push_effect(&mut self, effect: Effect) {
321 match &effect {
322 Effect::Notify { emitter } => {
323 if !self.pending_notifications.insert(*emitter) {
324 return;
325 }
326 }
327 Effect::NotifyGlobalObservers { global_type } => {
328 if !self.pending_global_notifications.insert(*global_type) {
329 return;
330 }
331 }
332 _ => {}
333 };
334
335 self.pending_effects.push_back(effect);
336 }
337
338 /// Called at the end of AppContext::update to complete any side effects
339 /// such as notifying observers, emitting events, etc. Effects can themselves
340 /// cause effects, so we continue looping until all effects are processed.
341 fn flush_effects(&mut self) {
342 loop {
343 self.release_dropped_entities();
344 self.release_dropped_focus_handles();
345 if let Some(effect) = self.pending_effects.pop_front() {
346 match effect {
347 Effect::Notify { emitter } => {
348 self.apply_notify_effect(emitter);
349 }
350 Effect::Emit { emitter, event } => self.apply_emit_effect(emitter, event),
351 Effect::FocusChanged {
352 window_handle,
353 focused,
354 } => {
355 self.apply_focus_changed_effect(window_handle, focused);
356 }
357 Effect::Refresh => {
358 self.apply_refresh_effect();
359 }
360 Effect::NotifyGlobalObservers { global_type } => {
361 self.apply_notify_global_observers_effect(global_type);
362 }
363 Effect::Defer { callback } => {
364 self.apply_defer_effect(callback);
365 }
366 }
367 } else {
368 break;
369 }
370 }
371
372 let dirty_window_ids = self
373 .windows
374 .iter()
375 .filter_map(|(_, window)| {
376 let window = window.as_ref().unwrap();
377 if window.dirty {
378 Some(window.handle.clone())
379 } else {
380 None
381 }
382 })
383 .collect::<SmallVec<[_; 8]>>();
384
385 for dirty_window_handle in dirty_window_ids {
386 self.update_window(dirty_window_handle, |cx| cx.draw())
387 .unwrap();
388 }
389 }
390
391 /// Repeatedly called during `flush_effects` to release any entities whose
392 /// reference count has become zero. We invoke any release observers before dropping
393 /// each entity.
394 fn release_dropped_entities(&mut self) {
395 loop {
396 let dropped = self.entities.take_dropped();
397 if dropped.is_empty() {
398 break;
399 }
400
401 for (entity_id, mut entity) in dropped {
402 self.observers.remove(&entity_id);
403 self.event_listeners.remove(&entity_id);
404 for mut release_callback in self.release_listeners.remove(&entity_id) {
405 release_callback(&mut entity, self);
406 }
407 }
408 }
409 }
410
411 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
412 /// For now, we simply blur the window if this happens, but we may want to support invoking
413 /// a window blur handler to restore focus to some logical element.
414 fn release_dropped_focus_handles(&mut self) {
415 for window_handle in self.windows() {
416 self.update_window(window_handle, |cx| {
417 let mut blur_window = false;
418 let focus = cx.window.focus;
419 cx.window.focus_handles.write().retain(|handle_id, count| {
420 if count.load(SeqCst) == 0 {
421 if focus == Some(handle_id) {
422 blur_window = true;
423 }
424 false
425 } else {
426 true
427 }
428 });
429
430 if blur_window {
431 cx.blur();
432 }
433 })
434 .unwrap();
435 }
436 }
437
438 fn apply_notify_effect(&mut self, emitter: EntityId) {
439 self.pending_notifications.remove(&emitter);
440 self.observers
441 .clone()
442 .retain(&emitter, |handler| handler(self));
443 }
444
445 fn apply_emit_effect(&mut self, emitter: EntityId, event: Box<dyn Any>) {
446 self.event_listeners
447 .clone()
448 .retain(&emitter, |handler| handler(event.as_ref(), self));
449 }
450
451 fn apply_focus_changed_effect(
452 &mut self,
453 window_handle: AnyWindowHandle,
454 focused: Option<FocusId>,
455 ) {
456 self.update_window(window_handle, |cx| {
457 if cx.window.focus == focused {
458 let mut listeners = mem::take(&mut cx.window.focus_listeners);
459 let focused =
460 focused.map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
461 let blurred = cx
462 .window
463 .last_blur
464 .take()
465 .unwrap()
466 .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
467 if focused.is_some() || blurred.is_some() {
468 let event = FocusEvent { focused, blurred };
469 for listener in &listeners {
470 listener(&event, cx);
471 }
472 }
473
474 listeners.extend(cx.window.focus_listeners.drain(..));
475 cx.window.focus_listeners = listeners;
476 }
477 })
478 .ok();
479 }
480
481 fn apply_refresh_effect(&mut self) {
482 for window in self.windows.values_mut() {
483 if let Some(window) = window.as_mut() {
484 window.dirty = true;
485 }
486 }
487 }
488
489 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
490 self.pending_global_notifications.remove(&type_id);
491 self.global_observers
492 .clone()
493 .retain(&type_id, |observer| observer(self));
494 }
495
496 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + Send + 'static>) {
497 callback(self);
498 }
499
500 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
501 /// so it can be held across `await` points.
502 pub fn to_async(&self) -> AsyncAppContext {
503 AsyncAppContext {
504 app: unsafe { mem::transmute(self.this.clone()) },
505 executor: self.executor.clone(),
506 }
507 }
508
509 /// Obtains a reference to the executor, which can be used to spawn futures.
510 pub fn executor(&self) -> &Executor {
511 &self.executor
512 }
513
514 /// Runs the given closure on the main thread, where interaction with the platform
515 /// is possible. The given closure will be invoked with a `MainThread<AppContext>`, which
516 /// has platform-specific methods that aren't present on `AppContext`.
517 pub fn run_on_main<R>(
518 &mut self,
519 f: impl FnOnce(&mut MainThread<AppContext>) -> R + Send + 'static,
520 ) -> Task<R>
521 where
522 R: Send + 'static,
523 {
524 if self.executor.is_main_thread() {
525 Task::ready(f(unsafe {
526 mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(self)
527 }))
528 } else {
529 let this = self.this.upgrade().unwrap();
530 self.executor.run_on_main(move || {
531 let cx = &mut *this.lock();
532 cx.update(|cx| f(unsafe { mem::transmute::<&mut Self, &mut MainThread<Self>>(cx) }))
533 })
534 }
535 }
536
537 /// Spawns the future returned by the given function on the main thread, where interaction with
538 /// the platform is possible. The given closure will be invoked with a `MainThread<AsyncAppContext>`,
539 /// which has platform-specific methods that aren't present on `AsyncAppContext`. The future will be
540 /// polled exclusively on the main thread.
541 // todo!("I think we need somehow to prevent the MainThread<AsyncAppContext> from implementing Send")
542 pub fn spawn_on_main<F, R>(
543 &self,
544 f: impl FnOnce(MainThread<AsyncAppContext>) -> F + Send + 'static,
545 ) -> Task<R>
546 where
547 F: Future<Output = R> + 'static,
548 R: Send + 'static,
549 {
550 let cx = self.to_async();
551 self.executor.spawn_on_main(move || f(MainThread(cx)))
552 }
553
554 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
555 /// with AsyncAppContext, which allows the application state to be accessed across await points.
556 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static) -> Task<R>
557 where
558 Fut: Future<Output = R> + Send + 'static,
559 R: Send + 'static,
560 {
561 let cx = self.to_async();
562 self.executor.spawn(async move {
563 let future = f(cx);
564 future.await
565 })
566 }
567
568 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
569 /// that are currently on the stack to be returned to the app.
570 pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static + Send) {
571 self.push_effect(Effect::Defer {
572 callback: Box::new(f),
573 });
574 }
575
576 /// Accessor for the application's asset source, which is provided when constructing the `App`.
577 pub fn asset_source(&self) -> &Arc<dyn AssetSource> {
578 &self.asset_source
579 }
580
581 /// Accessor for the text system.
582 pub fn text_system(&self) -> &Arc<TextSystem> {
583 &self.text_system
584 }
585
586 /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
587 pub fn text_style(&self) -> TextStyle {
588 let mut style = TextStyle::default();
589 for refinement in &self.text_style_stack {
590 style.refine(refinement);
591 }
592 style
593 }
594
595 /// Check whether a global of the given type has been assigned.
596 pub fn has_global<G: 'static>(&self) -> bool {
597 self.globals_by_type.contains_key(&TypeId::of::<G>())
598 }
599
600 /// Access the global of the given type. Panics if a global for that type has not been assigned.
601 pub fn global<G: 'static>(&self) -> &G {
602 self.globals_by_type
603 .get(&TypeId::of::<G>())
604 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
605 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
606 .unwrap()
607 }
608
609 /// Access the global of the given type if a value has been assigned.
610 pub fn try_global<G: 'static>(&self) -> Option<&G> {
611 self.globals_by_type
612 .get(&TypeId::of::<G>())
613 .map(|any_state| any_state.downcast_ref::<G>().unwrap())
614 }
615
616 /// Access the global of the given type mutably. Panics if a global for that type has not been assigned.
617 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
618 let global_type = TypeId::of::<G>();
619 self.push_effect(Effect::NotifyGlobalObservers { global_type });
620 self.globals_by_type
621 .get_mut(&global_type)
622 .and_then(|any_state| any_state.downcast_mut::<G>())
623 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
624 .unwrap()
625 }
626
627 /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
628 /// yet been assigned.
629 pub fn default_global<G: 'static + Default + Send>(&mut self) -> &mut G {
630 let global_type = TypeId::of::<G>();
631 self.push_effect(Effect::NotifyGlobalObservers { global_type });
632 self.globals_by_type
633 .entry(global_type)
634 .or_insert_with(|| Box::new(G::default()))
635 .downcast_mut::<G>()
636 .unwrap()
637 }
638
639 /// Set the value of the global of the given type.
640 pub fn set_global<G: Any + Send>(&mut self, global: G) {
641 let global_type = TypeId::of::<G>();
642 self.push_effect(Effect::NotifyGlobalObservers { global_type });
643 self.globals_by_type.insert(global_type, Box::new(global));
644 }
645
646 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
647 /// your closure with mutable access to the `AppContext` and the global simultaneously.
648 pub fn update_global<G: 'static, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R {
649 let mut global = self.lease_global::<G>();
650 let result = f(&mut global, self);
651 self.end_global_lease(global);
652 result
653 }
654
655 /// Register a callback to be invoked when a global of the given type is updated.
656 pub fn observe_global<G: 'static>(
657 &mut self,
658 mut f: impl FnMut(&mut Self) + Send + 'static,
659 ) -> Subscription {
660 self.global_observers.insert(
661 TypeId::of::<G>(),
662 Box::new(move |cx| {
663 f(cx);
664 true
665 }),
666 )
667 }
668
669 /// Move the global of the given type to the stack.
670 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
671 GlobalLease::new(
672 self.globals_by_type
673 .remove(&TypeId::of::<G>())
674 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
675 .unwrap(),
676 )
677 }
678
679 /// Restore the global of the given type after it is moved to the stack.
680 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
681 let global_type = TypeId::of::<G>();
682 self.push_effect(Effect::NotifyGlobalObservers { global_type });
683 self.globals_by_type.insert(global_type, lease.global);
684 }
685
686 pub fn observe_release<E: 'static>(
687 &mut self,
688 handle: &Handle<E>,
689 mut on_release: impl FnMut(&mut E, &mut AppContext) + Send + 'static,
690 ) -> Subscription {
691 self.release_listeners.insert(
692 handle.entity_id,
693 Box::new(move |entity, cx| {
694 let entity = entity.downcast_mut().expect("invalid entity type");
695 on_release(entity, cx)
696 }),
697 )
698 }
699
700 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
701 self.text_style_stack.push(text_style);
702 }
703
704 pub(crate) fn pop_text_style(&mut self) {
705 self.text_style_stack.pop();
706 }
707
708 /// Register key bindings.
709 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
710 self.keymap.lock().add_bindings(bindings);
711 self.pending_effects.push_back(Effect::Refresh);
712 }
713
714 /// Register a global listener for actions invoked via the keyboard.
715 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + Send + 'static) {
716 self.global_action_listeners
717 .entry(TypeId::of::<A>())
718 .or_default()
719 .push(Box::new(move |action, phase, cx| {
720 if phase == DispatchPhase::Bubble {
721 let action = action.as_any().downcast_ref().unwrap();
722 listener(action, cx)
723 }
724 }));
725 }
726
727 /// Register an action type to allow it to be referenced in keymaps.
728 pub fn register_action_type<A: Action>(&mut self) {
729 self.action_builders.insert(A::qualified_name(), A::build);
730 }
731
732 /// Construct an action based on its name and parameters.
733 pub fn build_action(
734 &mut self,
735 name: &str,
736 params: Option<serde_json::Value>,
737 ) -> Result<Box<dyn Action>> {
738 let build = self
739 .action_builders
740 .get(name)
741 .ok_or_else(|| anyhow!("no action type registered for {}", name))?;
742 (build)(params)
743 }
744
745 /// Halt propagation of a mouse event, keyboard event, or action. This prevents listeners
746 /// that have not yet been invoked from receiving the event.
747 pub fn stop_propagation(&mut self) {
748 self.propagate_event = false;
749 }
750}
751
752impl Context for AppContext {
753 type EntityContext<'a, T> = ModelContext<'a, T>;
754 type Result<T> = T;
755
756 /// Build an entity that is owned by the application. The given function will be invoked with
757 /// a `ModelContext` and must return an object representing the entity. A `Handle` will be returned
758 /// which can be used to access the entity in a context.
759 fn entity<T: 'static + Send>(
760 &mut self,
761 build_entity: impl FnOnce(&mut Self::EntityContext<'_, T>) -> T,
762 ) -> Handle<T> {
763 self.update(|cx| {
764 let slot = cx.entities.reserve();
765 let entity = build_entity(&mut ModelContext::mutable(cx, slot.downgrade()));
766 cx.entities.insert(slot, entity)
767 })
768 }
769
770 /// Update the entity referenced by the given handle. The function is passed a mutable reference to the
771 /// entity along with a `ModelContext` for the entity.
772 fn update_entity<T: 'static, R>(
773 &mut self,
774 handle: &Handle<T>,
775 update: impl FnOnce(&mut T, &mut Self::EntityContext<'_, T>) -> R,
776 ) -> R {
777 self.update(|cx| {
778 let mut entity = cx.entities.lease(handle);
779 let result = update(
780 &mut entity,
781 &mut ModelContext::mutable(cx, handle.downgrade()),
782 );
783 cx.entities.end_lease(entity);
784 result
785 })
786 }
787}
788
789impl<C> MainThread<C>
790where
791 C: Borrow<AppContext>,
792{
793 pub(crate) fn platform(&self) -> &dyn Platform {
794 self.0.borrow().platform.borrow_on_main_thread()
795 }
796
797 /// Instructs the platform to activate the application by bringing it to the foreground.
798 pub fn activate(&self, ignoring_other_apps: bool) {
799 self.platform().activate(ignoring_other_apps);
800 }
801
802 /// Writes data to the platform clipboard.
803 pub fn write_to_clipboard(&self, item: ClipboardItem) {
804 self.platform().write_to_clipboard(item)
805 }
806
807 /// Reads data from the platform clipboard.
808 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
809 self.platform().read_from_clipboard()
810 }
811
812 /// Writes credentials to the platform keychain.
813 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
814 self.platform().write_credentials(url, username, password)
815 }
816
817 /// Reads credentials from the platform keychain.
818 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
819 self.platform().read_credentials(url)
820 }
821
822 /// Deletes credentials from the platform keychain.
823 pub fn delete_credentials(&self, url: &str) -> Result<()> {
824 self.platform().delete_credentials(url)
825 }
826
827 /// Directs the platform's default browser to open the given URL.
828 pub fn open_url(&self, url: &str) {
829 self.platform().open_url(url);
830 }
831
832 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
833 self.platform().path_for_auxiliary_executable(name)
834 }
835}
836
837impl MainThread<AppContext> {
838 fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
839 self.0.update(|cx| {
840 update(unsafe {
841 std::mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx)
842 })
843 })
844 }
845
846 pub fn update_window<R>(
847 &mut self,
848 handle: AnyWindowHandle,
849 update: impl FnOnce(&mut MainThread<WindowContext>) -> R,
850 ) -> Result<R> {
851 self.0.update_window(handle, |cx| {
852 update(unsafe {
853 std::mem::transmute::<&mut WindowContext, &mut MainThread<WindowContext>>(cx)
854 })
855 })
856 }
857
858 pub fn update_window_root<V, R>(
859 &mut self,
860 handle: &WindowHandle<V>,
861 update: impl FnOnce(&mut V, &mut MainThread<ViewContext<'_, '_, V>>) -> R,
862 ) -> Result<R>
863 where
864 V: 'static,
865 {
866 self.update_window(handle.any_handle, |cx| {
867 let root_view = cx.window.root_view.as_ref().unwrap().downcast().unwrap();
868 root_view.update(cx, update)
869 })
870 }
871
872 /// Opens a new window with the given option and the root view returned by the given function.
873 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
874 /// functionality.
875 pub fn open_window<V: 'static>(
876 &mut self,
877 options: crate::WindowOptions,
878 build_root_view: impl FnOnce(&mut WindowContext) -> View<V> + Send + 'static,
879 ) -> WindowHandle<V> {
880 self.update(|cx| {
881 let id = cx.windows.insert(None);
882 let handle = WindowHandle::new(id);
883 let mut window = Window::new(handle.into(), options, cx);
884 let root_view = build_root_view(&mut WindowContext::mutable(cx, &mut window));
885 window.root_view.replace(root_view.into_any());
886 cx.windows.get_mut(id).unwrap().replace(window);
887 handle
888 })
889 }
890
891 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
892 /// your closure with mutable access to the `MainThread<AppContext>` and the global simultaneously.
893 pub fn update_global<G: 'static + Send, R>(
894 &mut self,
895 update: impl FnOnce(&mut G, &mut MainThread<AppContext>) -> R,
896 ) -> R {
897 self.0.update_global(|global, cx| {
898 let cx = unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) };
899 update(global, cx)
900 })
901 }
902}
903
904/// These effects are processed at the end of each application update cycle.
905pub(crate) enum Effect {
906 Notify {
907 emitter: EntityId,
908 },
909 Emit {
910 emitter: EntityId,
911 event: Box<dyn Any + Send + 'static>,
912 },
913 FocusChanged {
914 window_handle: AnyWindowHandle,
915 focused: Option<FocusId>,
916 },
917 Refresh,
918 NotifyGlobalObservers {
919 global_type: TypeId,
920 },
921 Defer {
922 callback: Box<dyn FnOnce(&mut AppContext) + Send + 'static>,
923 },
924}
925
926/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
927pub(crate) struct GlobalLease<G: 'static> {
928 global: AnyBox,
929 global_type: PhantomData<G>,
930}
931
932impl<G: 'static> GlobalLease<G> {
933 fn new(global: AnyBox) -> Self {
934 GlobalLease {
935 global,
936 global_type: PhantomData,
937 }
938 }
939}
940
941impl<G: 'static> Deref for GlobalLease<G> {
942 type Target = G;
943
944 fn deref(&self) -> &Self::Target {
945 self.global.downcast_ref().unwrap()
946 }
947}
948
949impl<G: 'static> DerefMut for GlobalLease<G> {
950 fn deref_mut(&mut self) -> &mut Self::Target {
951 self.global.downcast_mut().unwrap()
952 }
953}
954
955/// Contains state associated with an active drag operation, started by dragging an element
956/// within the window or by dragging into the app from the underlying platform.
957pub(crate) struct AnyDrag {
958 pub drag_handle_view: Option<AnyView>,
959 pub cursor_offset: Point<Pixels>,
960 pub state: AnyBox,
961 pub state_type: TypeId,
962}
963
964#[cfg(test)]
965mod tests {
966 use super::AppContext;
967
968 #[test]
969 fn test_app_context_send_sync() {
970 // This will not compile if `AppContext` does not implement `Send`
971 fn assert_send<T: Send>() {}
972 assert_send::<AppContext>();
973 }
974}