1use crate::{
2 AnyView, AnyWindowHandle, AppContext, AsyncAppContext, Context, Effect, Entity, EntityId,
3 EventEmitter, Model, Subscription, Task, View, WeakModel, WindowContext, WindowHandle,
4};
5use anyhow::Result;
6use derive_more::{Deref, DerefMut};
7use futures::FutureExt;
8use std::{
9 any::{Any, TypeId},
10 borrow::{Borrow, BorrowMut},
11 future::Future,
12};
13
14#[derive(Deref, DerefMut)]
15pub struct ModelContext<'a, T> {
16 #[deref]
17 #[deref_mut]
18 app: &'a mut AppContext,
19 model_state: WeakModel<T>,
20}
21
22impl<'a, T: 'static> ModelContext<'a, T> {
23 pub(crate) fn new(app: &'a mut AppContext, model_state: WeakModel<T>) -> Self {
24 Self { app, model_state }
25 }
26
27 pub fn entity_id(&self) -> EntityId {
28 self.model_state.entity_id
29 }
30
31 pub fn handle(&self) -> Model<T> {
32 self.weak_model()
33 .upgrade()
34 .expect("The entity must be alive if we have a model context")
35 }
36
37 pub fn weak_model(&self) -> WeakModel<T> {
38 self.model_state.clone()
39 }
40
41 pub fn observe<W, E>(
42 &mut self,
43 entity: &E,
44 mut on_notify: impl FnMut(&mut T, E, &mut ModelContext<'_, T>) + 'static,
45 ) -> Subscription
46 where
47 T: 'static,
48 W: 'static,
49 E: Entity<W>,
50 {
51 let this = self.weak_model();
52 self.app.observe_internal(entity, move |e, cx| {
53 if let Some(this) = this.upgrade() {
54 this.update(cx, |this, cx| on_notify(this, e, cx));
55 true
56 } else {
57 false
58 }
59 })
60 }
61
62 pub fn subscribe<T2, E, Evt>(
63 &mut self,
64 entity: &E,
65 mut on_event: impl FnMut(&mut T, E, &Evt, &mut ModelContext<'_, T>) + 'static,
66 ) -> Subscription
67 where
68 T: 'static,
69 T2: 'static + EventEmitter<Evt>,
70 E: Entity<T2>,
71 Evt: 'static,
72 {
73 let this = self.weak_model();
74 self.app.subscribe_internal(entity, move |e, event, cx| {
75 if let Some(this) = this.upgrade() {
76 this.update(cx, |this, cx| on_event(this, e, event, cx));
77 true
78 } else {
79 false
80 }
81 })
82 }
83
84 pub fn on_release(
85 &mut self,
86 on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
87 ) -> Subscription
88 where
89 T: 'static,
90 {
91 self.app.release_listeners.insert(
92 self.model_state.entity_id,
93 Box::new(move |this, cx| {
94 let this = this.downcast_mut().expect("invalid entity type");
95 on_release(this, cx);
96 }),
97 )
98 }
99
100 pub fn observe_release<T2, E>(
101 &mut self,
102 entity: &E,
103 on_release: impl FnOnce(&mut T, &mut T2, &mut ModelContext<'_, T>) + 'static,
104 ) -> Subscription
105 where
106 T: Any,
107 T2: 'static,
108 E: Entity<T2>,
109 {
110 let entity_id = entity.entity_id();
111 let this = self.weak_model();
112 self.app.release_listeners.insert(
113 entity_id,
114 Box::new(move |entity, cx| {
115 let entity = entity.downcast_mut().expect("invalid entity type");
116 if let Some(this) = this.upgrade() {
117 this.update(cx, |this, cx| on_release(this, entity, cx));
118 }
119 }),
120 )
121 }
122
123 pub fn observe_global<G: 'static>(
124 &mut self,
125 mut f: impl FnMut(&mut T, &mut ModelContext<'_, T>) + 'static,
126 ) -> Subscription
127 where
128 T: 'static,
129 {
130 let handle = self.weak_model();
131 self.global_observers.insert(
132 TypeId::of::<G>(),
133 Box::new(move |cx| handle.update(cx, |view, cx| f(view, cx)).is_ok()),
134 )
135 }
136
137 pub fn on_app_quit<Fut>(
138 &mut self,
139 mut on_quit: impl FnMut(&mut T, &mut ModelContext<T>) -> Fut + 'static,
140 ) -> Subscription
141 where
142 Fut: 'static + Future<Output = ()>,
143 T: 'static,
144 {
145 let handle = self.weak_model();
146 self.app.quit_observers.insert(
147 (),
148 Box::new(move |cx| {
149 let future = handle.update(cx, |entity, cx| on_quit(entity, cx)).ok();
150 async move {
151 if let Some(future) = future {
152 future.await;
153 }
154 }
155 .boxed_local()
156 }),
157 )
158 }
159
160 pub fn notify(&mut self) {
161 if self
162 .app
163 .pending_notifications
164 .insert(self.model_state.entity_id)
165 {
166 self.app.pending_effects.push_back(Effect::Notify {
167 emitter: self.model_state.entity_id,
168 });
169 }
170 }
171
172 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
173 where
174 G: 'static,
175 {
176 let mut global = self.app.lease_global::<G>();
177 let result = f(&mut global, self);
178 self.app.end_global_lease(global);
179 result
180 }
181
182 pub fn spawn<Fut, R>(&self, f: impl FnOnce(WeakModel<T>, AsyncAppContext) -> Fut) -> Task<R>
183 where
184 T: 'static,
185 Fut: Future<Output = R> + 'static,
186 R: 'static,
187 {
188 let this = self.weak_model();
189 self.app.spawn(|cx| f(this, cx))
190 }
191}
192
193impl<'a, T> ModelContext<'a, T> {
194 pub fn emit<Evt>(&mut self, event: Evt)
195 where
196 T: EventEmitter<Evt>,
197 Evt: 'static,
198 {
199 self.app.pending_effects.push_back(Effect::Emit {
200 emitter: self.model_state.entity_id,
201 event_type: TypeId::of::<Evt>(),
202 event: Box::new(event),
203 });
204 }
205}
206
207impl<'a, T> Context for ModelContext<'a, T> {
208 type Result<U> = U;
209
210 fn build_model<U: 'static>(
211 &mut self,
212 build_model: impl FnOnce(&mut ModelContext<'_, U>) -> U,
213 ) -> Model<U> {
214 self.app.build_model(build_model)
215 }
216
217 fn update_model<U: 'static, R>(
218 &mut self,
219 handle: &Model<U>,
220 update: impl FnOnce(&mut U, &mut ModelContext<'_, U>) -> R,
221 ) -> R {
222 self.app.update_model(handle, update)
223 }
224
225 fn update_window<R, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<R>
226 where
227 F: FnOnce(AnyView, &mut WindowContext<'_>) -> R,
228 {
229 self.app.update_window(window, update)
230 }
231
232 fn read_model<U, R>(
233 &self,
234 handle: &Model<U>,
235 read: impl FnOnce(&U, &AppContext) -> R,
236 ) -> Self::Result<R>
237 where
238 U: 'static,
239 {
240 self.app.read_model(handle, read)
241 }
242
243 fn read_window<U, R>(
244 &self,
245 window: &WindowHandle<U>,
246 read: impl FnOnce(View<U>, &AppContext) -> R,
247 ) -> Result<R>
248 where
249 U: 'static,
250 {
251 self.app.read_window(window, read)
252 }
253}
254
255impl<T> Borrow<AppContext> for ModelContext<'_, T> {
256 fn borrow(&self) -> &AppContext {
257 &self.app
258 }
259}
260
261impl<T> BorrowMut<AppContext> for ModelContext<'_, T> {
262 fn borrow_mut(&mut self) -> &mut AppContext {
263 &mut self.app
264 }
265}