1use crate::{
2 AnyView, AnyWindowHandle, App, AppCell, AppContext, BackgroundExecutor, BorrowAppContext,
3 Entity, EventEmitter, Focusable, ForegroundExecutor, Global, PromptButton, PromptLevel, Render,
4 Reservation, Result, Subscription, Task, VisualContext, Window, WindowHandle,
5};
6use anyhow::{Context as _, anyhow};
7use derive_more::{Deref, DerefMut};
8use futures::channel::oneshot;
9use std::{future::Future, rc::Weak};
10
11use super::{Context, WeakEntity};
12
13/// An async-friendly version of [App] with a static lifetime so it can be held across `await` points in async code.
14/// You're provided with an instance when calling [App::spawn], and you can also create one with [App::to_async].
15/// Internally, this holds a weak reference to an `App`, so its methods are fallible to protect against cases where the [App] is dropped.
16#[derive(Clone)]
17pub struct AsyncApp {
18 pub(crate) app: Weak<AppCell>,
19 pub(crate) background_executor: BackgroundExecutor,
20 pub(crate) foreground_executor: ForegroundExecutor,
21}
22
23impl AppContext for AsyncApp {
24 type Result<T> = Result<T>;
25
26 fn new<T: 'static>(
27 &mut self,
28 build_entity: impl FnOnce(&mut Context<T>) -> T,
29 ) -> Self::Result<Entity<T>> {
30 let app = self.app.upgrade().context("app was released")?;
31 let mut app = app.borrow_mut();
32 Ok(app.new(build_entity))
33 }
34
35 fn reserve_entity<T: 'static>(&mut self) -> Result<Reservation<T>> {
36 let app = self.app.upgrade().context("app was released")?;
37 let mut app = app.borrow_mut();
38 Ok(app.reserve_entity())
39 }
40
41 fn insert_entity<T: 'static>(
42 &mut self,
43 reservation: Reservation<T>,
44 build_entity: impl FnOnce(&mut Context<T>) -> T,
45 ) -> Result<Entity<T>> {
46 let app = self.app.upgrade().context("app was released")?;
47 let mut app = app.borrow_mut();
48 Ok(app.insert_entity(reservation, build_entity))
49 }
50
51 fn update_entity<T: 'static, R>(
52 &mut self,
53 handle: &Entity<T>,
54 update: impl FnOnce(&mut T, &mut Context<T>) -> R,
55 ) -> Self::Result<R> {
56 let app = self.app.upgrade().context("app was released")?;
57 let mut app = app.borrow_mut();
58 Ok(app.update_entity(handle, update))
59 }
60
61 fn as_mut<'a, T>(&'a mut self, _handle: &Entity<T>) -> Self::Result<super::GpuiBorrow<'a, T>>
62 where
63 T: 'static,
64 {
65 Err(anyhow!(
66 "Cannot as_mut with an async context. Try calling update() first"
67 ))
68 }
69
70 fn read_entity<T, R>(
71 &self,
72 handle: &Entity<T>,
73 callback: impl FnOnce(&T, &App) -> R,
74 ) -> Self::Result<R>
75 where
76 T: 'static,
77 {
78 let app = self.app.upgrade().context("app was released")?;
79 let lock = app.borrow();
80 Ok(lock.read_entity(handle, callback))
81 }
82
83 fn update_window<T, F>(&mut self, window: AnyWindowHandle, f: F) -> Result<T>
84 where
85 F: FnOnce(AnyView, &mut Window, &mut App) -> T,
86 {
87 let app = self.app.upgrade().context("app was released")?;
88 let mut lock = app.try_borrow_mut()?;
89 lock.update_window(window, f)
90 }
91
92 fn read_window<T, R>(
93 &self,
94 window: &WindowHandle<T>,
95 read: impl FnOnce(Entity<T>, &App) -> R,
96 ) -> Result<R>
97 where
98 T: 'static,
99 {
100 let app = self.app.upgrade().context("app was released")?;
101 let lock = app.borrow();
102 lock.read_window(window, read)
103 }
104
105 fn background_spawn<R>(&self, future: impl Future<Output = R> + Send + 'static) -> Task<R>
106 where
107 R: Send + 'static,
108 {
109 self.background_executor.spawn(future)
110 }
111
112 fn read_global<G, R>(&self, callback: impl FnOnce(&G, &App) -> R) -> Self::Result<R>
113 where
114 G: Global,
115 {
116 let app = self.app.upgrade().context("app was released")?;
117 let mut lock = app.borrow_mut();
118 Ok(lock.update(|this| this.read_global(callback)))
119 }
120}
121
122impl AsyncApp {
123 /// Schedules all windows in the application to be redrawn.
124 pub fn refresh(&self) -> Result<()> {
125 let app = self.app.upgrade().context("app was released")?;
126 let mut lock = app.borrow_mut();
127 lock.refresh_windows();
128 Ok(())
129 }
130
131 /// Get an executor which can be used to spawn futures in the background.
132 pub fn background_executor(&self) -> &BackgroundExecutor {
133 &self.background_executor
134 }
135
136 /// Get an executor which can be used to spawn futures in the foreground.
137 pub fn foreground_executor(&self) -> &ForegroundExecutor {
138 &self.foreground_executor
139 }
140
141 /// Invoke the given function in the context of the app, then flush any effects produced during its invocation.
142 pub fn update<R>(&self, f: impl FnOnce(&mut App) -> R) -> Result<R> {
143 let app = self.app.upgrade().context("app was released")?;
144 let mut lock = app.borrow_mut();
145 Ok(lock.update(f))
146 }
147
148 /// Arrange for the given callback to be invoked whenever the given entity emits an event of a given type.
149 /// The callback is provided a handle to the emitting entity and a reference to the emitted event.
150 pub fn subscribe<T, Event>(
151 &mut self,
152 entity: &Entity<T>,
153 mut on_event: impl FnMut(Entity<T>, &Event, &mut App) + 'static,
154 ) -> Result<Subscription>
155 where
156 T: 'static + EventEmitter<Event>,
157 Event: 'static,
158 {
159 let app = self.app.upgrade().context("app was released")?;
160 let mut lock = app.borrow_mut();
161 let subscription = lock.subscribe(entity, on_event);
162 Ok(subscription)
163 }
164
165 /// Open a window with the given options based on the root view returned by the given function.
166 pub fn open_window<V>(
167 &self,
168 options: crate::WindowOptions,
169 build_root_view: impl FnOnce(&mut Window, &mut App) -> Entity<V>,
170 ) -> Result<WindowHandle<V>>
171 where
172 V: 'static + Render,
173 {
174 let app = self.app.upgrade().context("app was released")?;
175 let mut lock = app.borrow_mut();
176 lock.open_window(options, build_root_view)
177 }
178
179 /// Schedule a future to be polled in the background.
180 #[track_caller]
181 pub fn spawn<AsyncFn, R>(&self, f: AsyncFn) -> Task<R>
182 where
183 AsyncFn: AsyncFnOnce(&mut AsyncApp) -> R + 'static,
184 R: 'static,
185 {
186 let mut cx = self.clone();
187 self.foreground_executor
188 .spawn(async move { f(&mut cx).await })
189 }
190
191 /// Determine whether global state of the specified type has been assigned.
192 /// Returns an error if the `App` has been dropped.
193 pub fn has_global<G: Global>(&self) -> Result<bool> {
194 let app = self.app.upgrade().context("app was released")?;
195 let app = app.borrow_mut();
196 Ok(app.has_global::<G>())
197 }
198
199 /// Reads the global state of the specified type, passing it to the given callback.
200 ///
201 /// Panics if no global state of the specified type has been assigned.
202 /// Returns an error if the `App` has been dropped.
203 pub fn read_global<G: Global, R>(&self, read: impl FnOnce(&G, &App) -> R) -> Result<R> {
204 let app = self.app.upgrade().context("app was released")?;
205 let app = app.borrow_mut();
206 Ok(read(app.global(), &app))
207 }
208
209 /// Reads the global state of the specified type, passing it to the given callback.
210 ///
211 /// Similar to [`AsyncApp::read_global`], but returns an error instead of panicking
212 /// if no state of the specified type has been assigned.
213 ///
214 /// Returns an error if no state of the specified type has been assigned the `App` has been dropped.
215 pub fn try_read_global<G: Global, R>(&self, read: impl FnOnce(&G, &App) -> R) -> Option<R> {
216 let app = self.app.upgrade()?;
217 let app = app.borrow_mut();
218 Some(read(app.try_global()?, &app))
219 }
220
221 /// A convenience method for [`App::update_global`](BorrowAppContext::update_global)
222 /// for updating the global state of the specified type.
223 pub fn update_global<G: Global, R>(
224 &self,
225 update: impl FnOnce(&mut G, &mut App) -> R,
226 ) -> Result<R> {
227 let app = self.app.upgrade().context("app was released")?;
228 let mut app = app.borrow_mut();
229 Ok(app.update(|cx| cx.update_global(update)))
230 }
231
232 /// Run something using this entity and cx, when the returned struct is dropped
233 pub fn on_drop<T: 'static, Callback: FnOnce(&mut T, &mut Context<T>) + 'static>(
234 &self,
235 entity: &WeakEntity<T>,
236 f: Callback,
237 ) -> util::Deferred<impl FnOnce() + use<T, Callback>> {
238 let entity = entity.clone();
239 let mut cx = self.clone();
240 util::defer(move || {
241 entity.update(&mut cx, f).ok();
242 })
243 }
244}
245
246/// A cloneable, owned handle to the application context,
247/// composed with the window associated with the current task.
248#[derive(Clone, Deref, DerefMut)]
249pub struct AsyncWindowContext {
250 #[deref]
251 #[deref_mut]
252 app: AsyncApp,
253 window: AnyWindowHandle,
254}
255
256impl AsyncWindowContext {
257 pub(crate) fn new_context(app: AsyncApp, window: AnyWindowHandle) -> Self {
258 Self { app, window }
259 }
260
261 /// Get the handle of the window this context is associated with.
262 pub fn window_handle(&self) -> AnyWindowHandle {
263 self.window
264 }
265
266 /// A convenience method for [`App::update_window`].
267 pub fn update<R>(&mut self, update: impl FnOnce(&mut Window, &mut App) -> R) -> Result<R> {
268 self.app
269 .update_window(self.window, |_, window, cx| update(window, cx))
270 }
271
272 /// A convenience method for [`App::update_window`].
273 pub fn update_root<R>(
274 &mut self,
275 update: impl FnOnce(AnyView, &mut Window, &mut App) -> R,
276 ) -> Result<R> {
277 self.app.update_window(self.window, update)
278 }
279
280 /// A convenience method for [`Window::on_next_frame`].
281 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut Window, &mut App) + 'static) {
282 self.window
283 .update(self, |_, window, _| window.on_next_frame(f))
284 .ok();
285 }
286
287 /// A convenience method for [`App::global`].
288 pub fn read_global<G: Global, R>(
289 &mut self,
290 read: impl FnOnce(&G, &Window, &App) -> R,
291 ) -> Result<R> {
292 self.window
293 .update(self, |_, window, cx| read(cx.global(), window, cx))
294 }
295
296 /// A convenience method for [`App::update_global`](BorrowAppContext::update_global).
297 /// for updating the global state of the specified type.
298 pub fn update_global<G, R>(
299 &mut self,
300 update: impl FnOnce(&mut G, &mut Window, &mut App) -> R,
301 ) -> Result<R>
302 where
303 G: Global,
304 {
305 self.window.update(self, |_, window, cx| {
306 cx.update_global(|global, cx| update(global, window, cx))
307 })
308 }
309
310 /// Schedule a future to be executed on the main thread. This is used for collecting
311 /// the results of background tasks and updating the UI.
312 #[track_caller]
313 pub fn spawn<AsyncFn, R>(&self, f: AsyncFn) -> Task<R>
314 where
315 AsyncFn: AsyncFnOnce(&mut AsyncWindowContext) -> R + 'static,
316 R: 'static,
317 {
318 let mut cx = self.clone();
319 self.foreground_executor
320 .spawn(async move { f(&mut cx).await })
321 }
322
323 /// Present a platform dialog.
324 /// The provided message will be presented, along with buttons for each answer.
325 /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
326 pub fn prompt<T>(
327 &mut self,
328 level: PromptLevel,
329 message: &str,
330 detail: Option<&str>,
331 answers: &[T],
332 ) -> oneshot::Receiver<usize>
333 where
334 T: Clone + Into<PromptButton>,
335 {
336 self.window
337 .update(self, |_, window, cx| {
338 window.prompt(level, message, detail, answers, cx)
339 })
340 .unwrap_or_else(|_| oneshot::channel().1)
341 }
342}
343
344impl AppContext for AsyncWindowContext {
345 type Result<T> = Result<T>;
346
347 fn new<T>(&mut self, build_entity: impl FnOnce(&mut Context<T>) -> T) -> Result<Entity<T>>
348 where
349 T: 'static,
350 {
351 self.window.update(self, |_, _, cx| cx.new(build_entity))
352 }
353
354 fn reserve_entity<T: 'static>(&mut self) -> Result<Reservation<T>> {
355 self.window.update(self, |_, _, cx| cx.reserve_entity())
356 }
357
358 fn insert_entity<T: 'static>(
359 &mut self,
360 reservation: Reservation<T>,
361 build_entity: impl FnOnce(&mut Context<T>) -> T,
362 ) -> Self::Result<Entity<T>> {
363 self.window
364 .update(self, |_, _, cx| cx.insert_entity(reservation, build_entity))
365 }
366
367 fn update_entity<T: 'static, R>(
368 &mut self,
369 handle: &Entity<T>,
370 update: impl FnOnce(&mut T, &mut Context<T>) -> R,
371 ) -> Result<R> {
372 self.window
373 .update(self, |_, _, cx| cx.update_entity(handle, update))
374 }
375
376 fn as_mut<'a, T>(&'a mut self, _: &Entity<T>) -> Self::Result<super::GpuiBorrow<'a, T>>
377 where
378 T: 'static,
379 {
380 Err(anyhow!(
381 "Cannot use as_mut() from an async context, call `update`"
382 ))
383 }
384
385 fn read_entity<T, R>(
386 &self,
387 handle: &Entity<T>,
388 read: impl FnOnce(&T, &App) -> R,
389 ) -> Self::Result<R>
390 where
391 T: 'static,
392 {
393 self.app.read_entity(handle, read)
394 }
395
396 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
397 where
398 F: FnOnce(AnyView, &mut Window, &mut App) -> T,
399 {
400 self.app.update_window(window, update)
401 }
402
403 fn read_window<T, R>(
404 &self,
405 window: &WindowHandle<T>,
406 read: impl FnOnce(Entity<T>, &App) -> R,
407 ) -> Result<R>
408 where
409 T: 'static,
410 {
411 self.app.read_window(window, read)
412 }
413
414 fn background_spawn<R>(&self, future: impl Future<Output = R> + Send + 'static) -> Task<R>
415 where
416 R: Send + 'static,
417 {
418 self.app.background_executor.spawn(future)
419 }
420
421 fn read_global<G, R>(&self, callback: impl FnOnce(&G, &App) -> R) -> Result<R>
422 where
423 G: Global,
424 {
425 self.app.read_global(callback)
426 }
427}
428
429impl VisualContext for AsyncWindowContext {
430 fn window_handle(&self) -> AnyWindowHandle {
431 self.window
432 }
433
434 fn new_window_entity<T: 'static>(
435 &mut self,
436 build_entity: impl FnOnce(&mut Window, &mut Context<T>) -> T,
437 ) -> Self::Result<Entity<T>> {
438 self.window
439 .update(self, |_, window, cx| cx.new(|cx| build_entity(window, cx)))
440 }
441
442 fn update_window_entity<T: 'static, R>(
443 &mut self,
444 view: &Entity<T>,
445 update: impl FnOnce(&mut T, &mut Window, &mut Context<T>) -> R,
446 ) -> Self::Result<R> {
447 self.window.update(self, |_, window, cx| {
448 view.update(cx, |entity, cx| update(entity, window, cx))
449 })
450 }
451
452 fn replace_root_view<V>(
453 &mut self,
454 build_view: impl FnOnce(&mut Window, &mut Context<V>) -> V,
455 ) -> Self::Result<Entity<V>>
456 where
457 V: 'static + Render,
458 {
459 self.window
460 .update(self, |_, window, cx| window.replace_root(cx, build_view))
461 }
462
463 fn focus<V>(&mut self, view: &Entity<V>) -> Self::Result<()>
464 where
465 V: Focusable,
466 {
467 self.window.update(self, |_, window, cx| {
468 view.read(cx).focus_handle(cx).focus(window);
469 })
470 }
471}