1mod async_context;
2mod entity_map;
3mod model_context;
4
5pub use async_context::*;
6pub use entity_map::*;
7pub use model_context::*;
8use refineable::Refineable;
9use smallvec::SmallVec;
10
11use crate::{
12 current_platform, image_cache::ImageCache, AssetSource, Context, DisplayId, Executor,
13 FocusEvent, FocusHandle, FocusId, LayoutId, MainThread, MainThreadOnly, Platform,
14 SubscriberSet, SvgRenderer, Task, TextStyle, TextStyleRefinement, TextSystem, View, Window,
15 WindowContext, WindowHandle, WindowId,
16};
17use anyhow::{anyhow, Result};
18use collections::{HashMap, HashSet, VecDeque};
19use futures::Future;
20use parking_lot::Mutex;
21use slotmap::SlotMap;
22use std::{
23 any::{type_name, Any, TypeId},
24 mem,
25 sync::{atomic::Ordering::SeqCst, Arc, Weak},
26};
27use util::http::{self, HttpClient};
28
29#[derive(Clone)]
30pub struct App(Arc<Mutex<AppContext>>);
31
32impl App {
33 pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
34 let http_client = http::client();
35 Self::new(current_platform(), asset_source, http_client)
36 }
37
38 #[cfg(any(test, feature = "test"))]
39 pub fn test() -> Self {
40 let platform = Arc::new(super::TestPlatform::new());
41 let asset_source = Arc::new(());
42 let http_client = util::http::FakeHttpClient::with_404_response();
43 Self::new(platform, asset_source, http_client)
44 }
45
46 fn new(
47 platform: Arc<dyn Platform>,
48 asset_source: Arc<dyn AssetSource>,
49 http_client: Arc<dyn HttpClient>,
50 ) -> Self {
51 let executor = platform.executor();
52 let entities = EntityMap::new();
53 let unit_entity = entities.insert(entities.reserve(), ());
54 Self(Arc::new_cyclic(|this| {
55 Mutex::new(AppContext {
56 this: this.clone(),
57 text_system: Arc::new(TextSystem::new(platform.text_system())),
58 pending_updates: 0,
59 flushing_effects: false,
60 next_frame_callbacks: Default::default(),
61 platform: MainThreadOnly::new(platform, executor.clone()),
62 executor,
63 svg_renderer: SvgRenderer::new(asset_source),
64 image_cache: ImageCache::new(http_client),
65 text_style_stack: Vec::new(),
66 global_stacks_by_type: HashMap::default(),
67 unit_entity,
68 entities,
69 windows: SlotMap::with_key(),
70 pending_notifications: Default::default(),
71 pending_effects: Default::default(),
72 observers: SubscriberSet::new(),
73 event_handlers: SubscriberSet::new(),
74 release_handlers: SubscriberSet::new(),
75 layout_id_buffer: Default::default(),
76 })
77 }))
78 }
79
80 pub fn run<F>(self, on_finish_launching: F)
81 where
82 F: 'static + FnOnce(&mut MainThread<AppContext>),
83 {
84 let this = self.clone();
85 let platform = self.0.lock().platform.clone();
86 platform.borrow_on_main_thread().run(Box::new(move || {
87 let cx = &mut *this.0.lock();
88 let cx = unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) };
89 on_finish_launching(cx);
90 }));
91 }
92}
93
94type Handler = Box<dyn Fn(&mut AppContext) -> bool + Send + Sync + 'static>;
95type EventHandler = Box<dyn Fn(&dyn Any, &mut AppContext) -> bool + Send + Sync + 'static>;
96type ReleaseHandler = Box<dyn Fn(&mut dyn Any, &mut AppContext) + Send + Sync + 'static>;
97type FrameCallback = Box<dyn FnOnce(&mut WindowContext) + Send>;
98
99pub struct AppContext {
100 this: Weak<Mutex<AppContext>>,
101 pub(crate) platform: MainThreadOnly<dyn Platform>,
102 text_system: Arc<TextSystem>,
103 flushing_effects: bool,
104 pending_updates: usize,
105 pub(crate) next_frame_callbacks: HashMap<DisplayId, Vec<FrameCallback>>,
106 pub(crate) executor: Executor,
107 pub(crate) svg_renderer: SvgRenderer,
108 pub(crate) image_cache: ImageCache,
109 pub(crate) text_style_stack: Vec<TextStyleRefinement>,
110 pub(crate) global_stacks_by_type: HashMap<TypeId, Vec<Box<dyn Any + Send + Sync>>>,
111 pub(crate) unit_entity: Handle<()>,
112 pub(crate) entities: EntityMap,
113 pub(crate) windows: SlotMap<WindowId, Option<Window>>,
114 pub(crate) pending_notifications: HashSet<EntityId>,
115 pending_effects: VecDeque<Effect>,
116 pub(crate) observers: SubscriberSet<EntityId, Handler>,
117 pub(crate) event_handlers: SubscriberSet<EntityId, EventHandler>,
118 pub(crate) release_handlers: SubscriberSet<EntityId, ReleaseHandler>,
119 pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
120}
121
122impl AppContext {
123 pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
124 self.pending_updates += 1;
125 let result = update(self);
126 if !self.flushing_effects && self.pending_updates == 1 {
127 self.flushing_effects = true;
128 self.flush_effects();
129 self.flushing_effects = false;
130 }
131 self.pending_updates -= 1;
132 result
133 }
134
135 pub(crate) fn update_window<R>(
136 &mut self,
137 id: WindowId,
138 update: impl FnOnce(&mut WindowContext) -> R,
139 ) -> Result<R> {
140 self.update(|cx| {
141 let mut window = cx
142 .windows
143 .get_mut(id)
144 .ok_or_else(|| anyhow!("window not found"))?
145 .take()
146 .unwrap();
147
148 let result = update(&mut WindowContext::mutable(cx, &mut window));
149
150 cx.windows
151 .get_mut(id)
152 .ok_or_else(|| anyhow!("window not found"))?
153 .replace(window);
154
155 Ok(result)
156 })
157 }
158
159 pub(crate) fn push_effect(&mut self, effect: Effect) {
160 match &effect {
161 Effect::Notify { emitter } => {
162 if self.pending_notifications.insert(*emitter) {
163 self.pending_effects.push_back(effect);
164 }
165 }
166 Effect::Emit { .. } => self.pending_effects.push_back(effect),
167 Effect::FocusChanged { .. } => self.pending_effects.push_back(effect),
168 }
169 }
170
171 fn flush_effects(&mut self) {
172 loop {
173 self.release_dropped_entities();
174 self.release_dropped_focus_handles();
175 if let Some(effect) = self.pending_effects.pop_front() {
176 match effect {
177 Effect::Notify { emitter } => self.apply_notify_effect(emitter),
178 Effect::Emit { emitter, event } => self.apply_emit_effect(emitter, event),
179 Effect::FocusChanged { window_id, focused } => {
180 self.apply_focus_changed(window_id, focused)
181 }
182 }
183 } else {
184 break;
185 }
186 }
187
188 let dirty_window_ids = self
189 .windows
190 .iter()
191 .filter_map(|(window_id, window)| {
192 let window = window.as_ref().unwrap();
193 if window.dirty {
194 Some(window_id)
195 } else {
196 None
197 }
198 })
199 .collect::<SmallVec<[_; 8]>>();
200
201 for dirty_window_id in dirty_window_ids {
202 self.update_window(dirty_window_id, |cx| cx.draw()).unwrap();
203 }
204 }
205
206 fn release_dropped_entities(&mut self) {
207 loop {
208 let dropped = self.entities.take_dropped();
209 if dropped.is_empty() {
210 break;
211 }
212
213 for (entity_id, mut entity) in dropped {
214 self.observers.remove(&entity_id);
215 self.event_handlers.remove(&entity_id);
216 for release_callback in self.release_handlers.remove(&entity_id) {
217 release_callback(&mut entity, self);
218 }
219 }
220 }
221 }
222
223 fn release_dropped_focus_handles(&mut self) {
224 let window_ids = self.windows.keys().collect::<SmallVec<[_; 8]>>();
225 for window_id in window_ids {
226 self.update_window(window_id, |cx| {
227 let mut blur_window = false;
228 let focus = cx.window.focus;
229 cx.window.focus_handles.write().retain(|handle_id, count| {
230 if count.load(SeqCst) == 0 {
231 if focus == Some(handle_id) {
232 blur_window = true;
233 }
234 false
235 } else {
236 true
237 }
238 });
239
240 if blur_window {
241 cx.blur();
242 }
243 })
244 .unwrap();
245 }
246 }
247
248 fn apply_notify_effect(&mut self, emitter: EntityId) {
249 self.pending_notifications.remove(&emitter);
250 self.observers
251 .clone()
252 .retain(&emitter, |handler| handler(self));
253 }
254
255 fn apply_emit_effect(&mut self, emitter: EntityId, event: Box<dyn Any>) {
256 self.event_handlers
257 .clone()
258 .retain(&emitter, |handler| handler(&event, self));
259 }
260
261 fn apply_focus_changed(&mut self, window_id: WindowId, focused: Option<FocusId>) {
262 self.update_window(window_id, |cx| {
263 if cx.window.focus == focused {
264 let mut listeners = mem::take(&mut cx.window.focus_listeners);
265 let focused =
266 focused.map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
267 let blurred = cx
268 .window
269 .last_blur
270 .take()
271 .unwrap()
272 .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
273 if focused.is_some() || blurred.is_some() {
274 let event = FocusEvent { focused, blurred };
275 for listener in &listeners {
276 listener(&event, cx);
277 }
278 }
279
280 listeners.extend(cx.window.focus_listeners.drain(..));
281 cx.window.focus_listeners = listeners;
282 }
283 })
284 .ok();
285 }
286
287 pub fn to_async(&self) -> AsyncAppContext {
288 AsyncAppContext(unsafe { mem::transmute(self.this.clone()) })
289 }
290
291 pub fn executor(&self) -> &Executor {
292 &self.executor
293 }
294
295 pub fn run_on_main<R>(
296 &mut self,
297 f: impl FnOnce(&mut MainThread<AppContext>) -> R + Send + 'static,
298 ) -> Task<R>
299 where
300 R: Send + 'static,
301 {
302 if self.executor.is_main_thread() {
303 Task::ready(f(unsafe {
304 mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(self)
305 }))
306 } else {
307 let this = self.this.upgrade().unwrap();
308 self.executor.run_on_main(move || {
309 let cx = &mut *this.lock();
310 cx.update(|cx| f(unsafe { mem::transmute::<&mut Self, &mut MainThread<Self>>(cx) }))
311 })
312 }
313 }
314
315 pub fn spawn_on_main<F, R>(
316 &self,
317 f: impl FnOnce(&mut MainThread<AppContext>) -> F + Send + 'static,
318 ) -> Task<R>
319 where
320 F: Future<Output = R> + 'static,
321 R: Send + 'static,
322 {
323 let this = self.this.upgrade().unwrap();
324 self.executor.spawn_on_main(move || {
325 let cx = &mut *this.lock();
326 cx.update(|cx| {
327 f(unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) })
328 })
329 })
330 }
331
332 pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static) -> Task<R>
333 where
334 Fut: Future<Output = R> + Send + 'static,
335 R: Send + 'static,
336 {
337 let cx = self.to_async();
338 self.executor.spawn(async move {
339 let future = f(cx);
340 future.await
341 })
342 }
343
344 pub fn text_system(&self) -> &Arc<TextSystem> {
345 &self.text_system
346 }
347
348 pub fn text_style(&self) -> TextStyle {
349 let mut style = TextStyle::default();
350 for refinement in &self.text_style_stack {
351 style.refine(refinement);
352 }
353 style
354 }
355
356 pub fn global<G: 'static>(&self) -> &G {
357 self.global_stacks_by_type
358 .get(&TypeId::of::<G>())
359 .and_then(|stack| stack.last())
360 .and_then(|any_state| any_state.downcast_ref::<G>())
361 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
362 .unwrap()
363 }
364
365 pub fn global_mut<G: 'static>(&mut self) -> &mut G {
366 self.global_stacks_by_type
367 .get_mut(&TypeId::of::<G>())
368 .and_then(|stack| stack.last_mut())
369 .and_then(|any_state| any_state.downcast_mut::<G>())
370 .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
371 .unwrap()
372 }
373
374 pub fn default_global<G: 'static + Default + Sync + Send>(&mut self) -> &mut G {
375 let stack = self
376 .global_stacks_by_type
377 .entry(TypeId::of::<G>())
378 .or_default();
379 if stack.is_empty() {
380 stack.push(Box::new(G::default()));
381 }
382 stack.last_mut().unwrap().downcast_mut::<G>().unwrap()
383 }
384
385 pub(crate) fn push_global<T: Send + Sync + 'static>(&mut self, state: T) {
386 self.global_stacks_by_type
387 .entry(TypeId::of::<T>())
388 .or_default()
389 .push(Box::new(state));
390 }
391
392 pub(crate) fn pop_global<T: 'static>(&mut self) {
393 self.global_stacks_by_type
394 .get_mut(&TypeId::of::<T>())
395 .and_then(|stack| stack.pop())
396 .expect("state stack underflow");
397 }
398
399 pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
400 self.text_style_stack.push(text_style);
401 }
402
403 pub(crate) fn pop_text_style(&mut self) {
404 self.text_style_stack.pop();
405 }
406}
407
408impl Context for AppContext {
409 type EntityContext<'a, 'w, T: Send + Sync + 'static> = ModelContext<'a, T>;
410 type Result<T> = T;
411
412 fn entity<T: Send + Sync + 'static>(
413 &mut self,
414 build_entity: impl FnOnce(&mut Self::EntityContext<'_, '_, T>) -> T,
415 ) -> Handle<T> {
416 self.update(|cx| {
417 let slot = cx.entities.reserve();
418 let entity = build_entity(&mut ModelContext::mutable(cx, slot.id));
419 cx.entities.insert(slot, entity)
420 })
421 }
422
423 fn update_entity<T: Send + Sync + 'static, R>(
424 &mut self,
425 handle: &Handle<T>,
426 update: impl FnOnce(&mut T, &mut Self::EntityContext<'_, '_, T>) -> R,
427 ) -> R {
428 self.update(|cx| {
429 let mut entity = cx.entities.lease(handle);
430 let result = update(&mut entity, &mut ModelContext::mutable(cx, handle.id));
431 cx.entities.end_lease(entity);
432 result
433 })
434 }
435}
436
437impl MainThread<AppContext> {
438 fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
439 self.0.update(|cx| {
440 update(unsafe {
441 std::mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx)
442 })
443 })
444 }
445
446 pub(crate) fn update_window<R>(
447 &mut self,
448 id: WindowId,
449 update: impl FnOnce(&mut MainThread<WindowContext>) -> R,
450 ) -> Result<R> {
451 self.0.update_window(id, |cx| {
452 update(unsafe {
453 std::mem::transmute::<&mut WindowContext, &mut MainThread<WindowContext>>(cx)
454 })
455 })
456 }
457
458 pub(crate) fn platform(&self) -> &dyn Platform {
459 self.platform.borrow_on_main_thread()
460 }
461
462 pub fn activate(&mut self, ignoring_other_apps: bool) {
463 self.platform().activate(ignoring_other_apps);
464 }
465
466 pub fn open_window<S: 'static + Send + Sync>(
467 &mut self,
468 options: crate::WindowOptions,
469 build_root_view: impl FnOnce(&mut WindowContext) -> View<S> + Send + 'static,
470 ) -> WindowHandle<S> {
471 self.update(|cx| {
472 let id = cx.windows.insert(None);
473 let handle = WindowHandle::new(id);
474 let mut window = Window::new(handle.into(), options, cx);
475 let root_view = build_root_view(&mut WindowContext::mutable(cx, &mut window));
476 window.root_view.replace(root_view.into_any());
477 cx.windows.get_mut(id).unwrap().replace(window);
478 handle
479 })
480 }
481}
482
483pub(crate) enum Effect {
484 Notify {
485 emitter: EntityId,
486 },
487 Emit {
488 emitter: EntityId,
489 event: Box<dyn Any + Send + Sync + 'static>,
490 },
491 FocusChanged {
492 window_id: WindowId,
493 focused: Option<FocusId>,
494 },
495}
496
497#[cfg(test)]
498mod tests {
499 use super::AppContext;
500
501 #[test]
502 fn test_app_context_send_sync() {
503 // This will not compile if `AppContext` does not implement `Send`
504 fn assert_send<T: Send>() {}
505 assert_send::<AppContext>();
506 }
507}