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, Window, WindowContext, WindowHandle,
21 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(crate) fn push_effect(&mut self, effect: Effect) {
307 match &effect {
308 Effect::Notify { emitter } => {
309 if !self.pending_notifications.insert(*emitter) {
310 return;
311 }
312 }
313 Effect::NotifyGlobalObservers { global_type } => {
314 if !self.pending_global_notifications.insert(*global_type) {
315 return;
316 }
317 }
318 _ => {}
319 };
320
321 self.pending_effects.push_back(effect);
322 }
323
324 /// Called at the end of AppContext::update to complete any side effects
325 /// such as notifying observers, emitting events, etc. Effects can themselves
326 /// cause effects, so we continue looping until all effects are processed.
327 fn flush_effects(&mut self) {
328 loop {
329 self.release_dropped_entities();
330 self.release_dropped_focus_handles();
331 if let Some(effect) = self.pending_effects.pop_front() {
332 match effect {
333 Effect::Notify { emitter } => {
334 self.apply_notify_effect(emitter);
335 }
336 Effect::Emit { emitter, event } => self.apply_emit_effect(emitter, event),
337 Effect::FocusChanged {
338 window_handle,
339 focused,
340 } => {
341 self.apply_focus_changed_effect(window_handle, focused);
342 }
343 Effect::Refresh => {
344 self.apply_refresh_effect();
345 }
346 Effect::NotifyGlobalObservers { global_type } => {
347 self.apply_notify_global_observers_effect(global_type);
348 }
349 Effect::Defer { callback } => {
350 self.apply_defer_effect(callback);
351 }
352 }
353 } else {
354 break;
355 }
356 }
357
358 let dirty_window_ids = self
359 .windows
360 .iter()
361 .filter_map(|(_, window)| {
362 let window = window.as_ref().unwrap();
363 if window.dirty {
364 Some(window.handle.clone())
365 } else {
366 None
367 }
368 })
369 .collect::<SmallVec<[_; 8]>>();
370
371 for dirty_window_handle in dirty_window_ids {
372 self.update_window(dirty_window_handle, |cx| cx.draw())
373 .unwrap();
374 }
375 }
376
377 /// Repeatedly called during `flush_effects` to release any entities whose
378 /// reference count has become zero. We invoke any release observers before dropping
379 /// each entity.
380 fn release_dropped_entities(&mut self) {
381 loop {
382 let dropped = self.entities.take_dropped();
383 if dropped.is_empty() {
384 break;
385 }
386
387 for (entity_id, mut entity) in dropped {
388 self.observers.remove(&entity_id);
389 self.event_listeners.remove(&entity_id);
390 for mut release_callback in self.release_listeners.remove(&entity_id) {
391 release_callback(&mut entity, self);
392 }
393 }
394 }
395 }
396
397 /// Repeatedly called during `flush_effects` to handle a focused handle being dropped.
398 /// For now, we simply blur the window if this happens, but we may want to support invoking
399 /// a window blur handler to restore focus to some logical element.
400 fn release_dropped_focus_handles(&mut self) {
401 for window_handle in self.windows() {
402 self.update_window(window_handle, |cx| {
403 let mut blur_window = false;
404 let focus = cx.window.focus;
405 cx.window.focus_handles.write().retain(|handle_id, count| {
406 if count.load(SeqCst) == 0 {
407 if focus == Some(handle_id) {
408 blur_window = true;
409 }
410 false
411 } else {
412 true
413 }
414 });
415
416 if blur_window {
417 cx.blur();
418 }
419 })
420 .unwrap();
421 }
422 }
423
424 fn apply_notify_effect(&mut self, emitter: EntityId) {
425 self.pending_notifications.remove(&emitter);
426 self.observers
427 .clone()
428 .retain(&emitter, |handler| handler(self));
429 }
430
431 fn apply_emit_effect(&mut self, emitter: EntityId, event: Box<dyn Any>) {
432 self.event_listeners
433 .clone()
434 .retain(&emitter, |handler| handler(event.as_ref(), self));
435 }
436
437 fn apply_focus_changed_effect(
438 &mut self,
439 window_handle: AnyWindowHandle,
440 focused: Option<FocusId>,
441 ) {
442 self.update_window(window_handle, |cx| {
443 if cx.window.focus == focused {
444 let mut listeners = mem::take(&mut cx.window.focus_listeners);
445 let focused =
446 focused.map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
447 let blurred = cx
448 .window
449 .last_blur
450 .take()
451 .unwrap()
452 .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
453 if focused.is_some() || blurred.is_some() {
454 let event = FocusEvent { focused, blurred };
455 for listener in &listeners {
456 listener(&event, cx);
457 }
458 }
459
460 listeners.extend(cx.window.focus_listeners.drain(..));
461 cx.window.focus_listeners = listeners;
462 }
463 })
464 .ok();
465 }
466
467 fn apply_refresh_effect(&mut self) {
468 for window in self.windows.values_mut() {
469 if let Some(window) = window.as_mut() {
470 window.dirty = true;
471 }
472 }
473 }
474
475 fn apply_notify_global_observers_effect(&mut self, type_id: TypeId) {
476 self.pending_global_notifications.remove(&type_id);
477 self.global_observers
478 .clone()
479 .retain(&type_id, |observer| observer(self));
480 }
481
482 fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + Send + 'static>) {
483 callback(self);
484 }
485
486 /// Creates an `AsyncAppContext`, which can be cloned and has a static lifetime
487 /// so it can be held across `await` points.
488 pub fn to_async(&self) -> AsyncAppContext {
489 AsyncAppContext {
490 app: unsafe { mem::transmute(self.this.clone()) },
491 executor: self.executor.clone(),
492 }
493 }
494
495 /// Obtains a reference to the executor, which can be used to spawn futures.
496 pub fn executor(&self) -> &Executor {
497 &self.executor
498 }
499
500 /// Runs the given closure on the main thread, where interaction with the platform
501 /// is possible. The given closure will be invoked with a `MainThread<AppContext>`, which
502 /// has platform-specific methods that aren't present on `AppContext`.
503 pub fn run_on_main<R>(
504 &mut self,
505 f: impl FnOnce(&mut MainThread<AppContext>) -> R + Send + 'static,
506 ) -> Task<R>
507 where
508 R: Send + 'static,
509 {
510 if self.executor.is_main_thread() {
511 Task::ready(f(unsafe {
512 mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(self)
513 }))
514 } else {
515 let this = self.this.upgrade().unwrap();
516 self.executor.run_on_main(move || {
517 let cx = &mut *this.lock();
518 cx.update(|cx| f(unsafe { mem::transmute::<&mut Self, &mut MainThread<Self>>(cx) }))
519 })
520 }
521 }
522
523 /// Spawns the future returned by the given function on the main thread, where interaction with
524 /// the platform is possible. The given closure will be invoked with a `MainThread<AsyncAppContext>`,
525 /// which has platform-specific methods that aren't present on `AsyncAppContext`. The future will be
526 /// polled exclusively on the main thread.
527 // todo!("I think we need somehow to prevent the MainThread<AsyncAppContext> from implementing Send")
528 pub fn spawn_on_main<F, R>(
529 &self,
530 f: impl FnOnce(MainThread<AsyncAppContext>) -> F + Send + 'static,
531 ) -> Task<R>
532 where
533 F: Future<Output = R> + 'static,
534 R: Send + 'static,
535 {
536 let cx = self.to_async();
537 self.executor.spawn_on_main(move || f(MainThread(cx)))
538 }
539
540 /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
541 /// with AsyncAppContext, which allows the application state to be accessed across await points.
542 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static) -> Task<R>
543 where
544 Fut: Future<Output = R> + Send + 'static,
545 R: Send + 'static,
546 {
547 let cx = self.to_async();
548 self.executor.spawn(async move {
549 let future = f(cx);
550 future.await
551 })
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 + Send) {
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 + Send>(&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 + Send>(&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) + Send + '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 /// Move the global of the given type to the stack.
656 pub(crate) fn lease_global<G: 'static>(&mut self) -> GlobalLease<G> {
657 GlobalLease::new(
658 self.globals_by_type
659 .remove(&TypeId::of::<G>())
660 .ok_or_else(|| anyhow!("no global registered of type {}", type_name::<G>()))
661 .unwrap(),
662 )
663 }
664
665 /// Restore the global of the given type after it is moved to the stack.
666 pub(crate) fn end_global_lease<G: 'static>(&mut self, lease: GlobalLease<G>) {
667 let global_type = TypeId::of::<G>();
668 self.push_effect(Effect::NotifyGlobalObservers { global_type });
669 self.globals_by_type.insert(global_type, lease.global);
670 }
671
672 pub fn observe_release<E: 'static>(
673 &mut self,
674 handle: &Handle<E>,
675 mut on_release: impl FnMut(&mut E, &mut AppContext) + Send + 'static,
676 ) -> Subscription {
677 self.release_listeners.insert(
678 handle.entity_id,
679 Box::new(move |entity, cx| {
680 let entity = entity.downcast_mut().expect("invalid entity type");
681 on_release(entity, cx)
682 }),
683 )
684 }
685
686 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
687 self.text_style_stack.push(text_style);
688 }
689
690 pub(crate) fn pop_text_style(&mut self) {
691 self.text_style_stack.pop();
692 }
693
694 /// Register key bindings.
695 pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
696 self.keymap.lock().add_bindings(bindings);
697 self.pending_effects.push_back(Effect::Refresh);
698 }
699
700 /// Register a global listener for actions invoked via the keyboard.
701 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + Send + 'static) {
702 self.global_action_listeners
703 .entry(TypeId::of::<A>())
704 .or_default()
705 .push(Box::new(move |action, phase, cx| {
706 if phase == DispatchPhase::Bubble {
707 let action = action.as_any().downcast_ref().unwrap();
708 listener(action, cx)
709 }
710 }));
711 }
712
713 /// Register an action type to allow it to be referenced in keymaps.
714 pub fn register_action_type<A: Action>(&mut self) {
715 self.action_builders.insert(A::qualified_name(), A::build);
716 }
717
718 /// Construct an action based on its name and parameters.
719 pub fn build_action(
720 &mut self,
721 name: &str,
722 params: Option<serde_json::Value>,
723 ) -> Result<Box<dyn Action>> {
724 let build = self
725 .action_builders
726 .get(name)
727 .ok_or_else(|| anyhow!("no action type registered for {}", name))?;
728 (build)(params)
729 }
730
731 /// Halt propagation of a mouse event, keyboard event, or action. This prevents listeners
732 /// that have not yet been invoked from receiving the event.
733 pub fn stop_propagation(&mut self) {
734 self.propagate_event = false;
735 }
736}
737
738impl Context for AppContext {
739 type EntityContext<'a, T> = ModelContext<'a, T>;
740 type Result<T> = T;
741
742 /// Build an entity that is owned by the application. The given function will be invoked with
743 /// a `ModelContext` and must return an object representing the entity. A `Handle` will be returned
744 /// which can be used to access the entity in a context.
745 fn entity<T: 'static + Send>(
746 &mut self,
747 build_entity: impl FnOnce(&mut Self::EntityContext<'_, T>) -> T,
748 ) -> Handle<T> {
749 self.update(|cx| {
750 let slot = cx.entities.reserve();
751 let entity = build_entity(&mut ModelContext::mutable(cx, slot.downgrade()));
752 cx.entities.insert(slot, entity)
753 })
754 }
755
756 /// Update the entity referenced by the given handle. The function is passed a mutable reference to the
757 /// entity along with a `ModelContext` for the entity.
758 fn update_entity<T: 'static, R>(
759 &mut self,
760 handle: &Handle<T>,
761 update: impl FnOnce(&mut T, &mut Self::EntityContext<'_, T>) -> R,
762 ) -> R {
763 self.update(|cx| {
764 let mut entity = cx.entities.lease(handle);
765 let result = update(
766 &mut entity,
767 &mut ModelContext::mutable(cx, handle.downgrade()),
768 );
769 cx.entities.end_lease(entity);
770 result
771 })
772 }
773}
774
775impl<C> MainThread<C>
776where
777 C: Borrow<AppContext>,
778{
779 pub(crate) fn platform(&self) -> &dyn Platform {
780 self.0.borrow().platform.borrow_on_main_thread()
781 }
782
783 /// Instructs the platform to activate the application by bringing it to the foreground.
784 pub fn activate(&self, ignoring_other_apps: bool) {
785 self.platform().activate(ignoring_other_apps);
786 }
787
788 /// Writes data to the platform clipboard.
789 pub fn write_to_clipboard(&self, item: ClipboardItem) {
790 self.platform().write_to_clipboard(item)
791 }
792
793 /// Reads data from the platform clipboard.
794 pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
795 self.platform().read_from_clipboard()
796 }
797
798 /// Writes credentials to the platform keychain.
799 pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
800 self.platform().write_credentials(url, username, password)
801 }
802
803 /// Reads credentials from the platform keychain.
804 pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
805 self.platform().read_credentials(url)
806 }
807
808 /// Deletes credentials from the platform keychain.
809 pub fn delete_credentials(&self, url: &str) -> Result<()> {
810 self.platform().delete_credentials(url)
811 }
812
813 /// Directs the platform's default browser to open the given URL.
814 pub fn open_url(&self, url: &str) {
815 self.platform().open_url(url);
816 }
817
818 pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
819 self.platform().path_for_auxiliary_executable(name)
820 }
821}
822
823impl MainThread<AppContext> {
824 fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
825 self.0.update(|cx| {
826 update(unsafe {
827 std::mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx)
828 })
829 })
830 }
831
832 pub fn update_window<R>(
833 &mut self,
834 handle: AnyWindowHandle,
835 update: impl FnOnce(&mut MainThread<WindowContext>) -> R,
836 ) -> Result<R> {
837 self.0.update_window(handle, |cx| {
838 update(unsafe {
839 std::mem::transmute::<&mut WindowContext, &mut MainThread<WindowContext>>(cx)
840 })
841 })
842 }
843
844 /// Opens a new window with the given option and the root view returned by the given function.
845 /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
846 /// functionality.
847 pub fn open_window<V: 'static>(
848 &mut self,
849 options: crate::WindowOptions,
850 build_root_view: impl FnOnce(&mut WindowContext) -> View<V> + Send + 'static,
851 ) -> WindowHandle<V> {
852 self.update(|cx| {
853 let id = cx.windows.insert(None);
854 let handle = WindowHandle::new(id);
855 let mut window = Window::new(handle.into(), options, cx);
856 let root_view = build_root_view(&mut WindowContext::mutable(cx, &mut window));
857 window.root_view.replace(root_view.into_any());
858 cx.windows.get_mut(id).unwrap().replace(window);
859 handle
860 })
861 }
862
863 /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
864 /// your closure with mutable access to the `MainThread<AppContext>` and the global simultaneously.
865 pub fn update_global<G: 'static + Send, R>(
866 &mut self,
867 update: impl FnOnce(&mut G, &mut MainThread<AppContext>) -> R,
868 ) -> R {
869 self.0.update_global(|global, cx| {
870 let cx = unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) };
871 update(global, cx)
872 })
873 }
874}
875
876/// These effects are processed at the end of each application update cycle.
877pub(crate) enum Effect {
878 Notify {
879 emitter: EntityId,
880 },
881 Emit {
882 emitter: EntityId,
883 event: Box<dyn Any + Send + 'static>,
884 },
885 FocusChanged {
886 window_handle: AnyWindowHandle,
887 focused: Option<FocusId>,
888 },
889 Refresh,
890 NotifyGlobalObservers {
891 global_type: TypeId,
892 },
893 Defer {
894 callback: Box<dyn FnOnce(&mut AppContext) + Send + 'static>,
895 },
896}
897
898/// Wraps a global variable value during `update_global` while the value has been moved to the stack.
899pub(crate) struct GlobalLease<G: 'static> {
900 global: AnyBox,
901 global_type: PhantomData<G>,
902}
903
904impl<G: 'static> GlobalLease<G> {
905 fn new(global: AnyBox) -> Self {
906 GlobalLease {
907 global,
908 global_type: PhantomData,
909 }
910 }
911}
912
913impl<G: 'static> Deref for GlobalLease<G> {
914 type Target = G;
915
916 fn deref(&self) -> &Self::Target {
917 self.global.downcast_ref().unwrap()
918 }
919}
920
921impl<G: 'static> DerefMut for GlobalLease<G> {
922 fn deref_mut(&mut self) -> &mut Self::Target {
923 self.global.downcast_mut().unwrap()
924 }
925}
926
927/// Contains state associated with an active drag operation, started by dragging an element
928/// within the window or by dragging into the app from the underlying platform.
929pub(crate) struct AnyDrag {
930 pub drag_handle_view: Option<AnyView>,
931 pub cursor_offset: Point<Pixels>,
932 pub state: AnyBox,
933 pub state_type: TypeId,
934}
935
936#[cfg(test)]
937mod tests {
938 use super::AppContext;
939
940 #[test]
941 fn test_app_context_send_sync() {
942 // This will not compile if `AppContext` does not implement `Send`
943 fn assert_send<T: Send>() {}
944 assert_send::<AppContext>();
945 }
946}