1use crate::{
2 private::Sealed, AnyElement, AnyModel, AnyWeakModel, AppContext, AvailableSpace, BorrowWindow,
3 Bounds, Element, ElementId, Entity, EntityId, Flatten, FocusHandle, FocusableView, IntoElement,
4 LayoutId, Model, Pixels, Point, Render, Size, ViewContext, VisualContext, WeakModel,
5 WindowContext,
6};
7use anyhow::{Context, Result};
8use std::{
9 any::TypeId,
10 fmt,
11 hash::{Hash, Hasher},
12};
13
14pub struct View<V> {
15 pub model: Model<V>,
16}
17
18impl<V> Sealed for View<V> {}
19
20impl<V: 'static> Entity<V> for View<V> {
21 type Weak = WeakView<V>;
22
23 fn entity_id(&self) -> EntityId {
24 self.model.entity_id
25 }
26
27 fn downgrade(&self) -> Self::Weak {
28 WeakView {
29 model: self.model.downgrade(),
30 }
31 }
32
33 fn upgrade_from(weak: &Self::Weak) -> Option<Self>
34 where
35 Self: Sized,
36 {
37 let model = weak.model.upgrade()?;
38 Some(View { model })
39 }
40}
41
42impl<V: 'static> View<V> {
43 /// Convert this strong view reference into a weak view reference.
44 pub fn downgrade(&self) -> WeakView<V> {
45 Entity::downgrade(self)
46 }
47
48 pub fn update<C, R>(
49 &self,
50 cx: &mut C,
51 f: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
52 ) -> C::Result<R>
53 where
54 C: VisualContext,
55 {
56 cx.update_view(self, f)
57 }
58
59 pub fn read<'a>(&self, cx: &'a AppContext) -> &'a V {
60 self.model.read(cx)
61 }
62
63 // pub fn render_with<E>(&self, component: E) -> RenderViewWith<E, V>
64 // where
65 // E: 'static + Element,
66 // {
67 // RenderViewWith {
68 // view: self.clone(),
69 // element: Some(component),
70 // }
71 // }
72
73 pub fn focus_handle(&self, cx: &AppContext) -> FocusHandle
74 where
75 V: FocusableView,
76 {
77 self.read(cx).focus_handle(cx)
78 }
79}
80
81impl<V: Render> Element for View<V> {
82 type State = Option<AnyElement>;
83
84 fn request_layout(
85 &mut self,
86 _state: Option<Self::State>,
87 cx: &mut WindowContext,
88 ) -> (LayoutId, Self::State) {
89 let mut element = self.update(cx, |view, cx| view.render(cx).into_any_element());
90 let layout_id = element.request_layout(cx);
91 (layout_id, Some(element))
92 }
93
94 fn paint(&mut self, _: Bounds<Pixels>, element: &mut Self::State, cx: &mut WindowContext) {
95 element.take().unwrap().paint(cx);
96 }
97}
98
99impl<V> Clone for View<V> {
100 fn clone(&self) -> Self {
101 Self {
102 model: self.model.clone(),
103 }
104 }
105}
106
107impl<V> Hash for View<V> {
108 fn hash<H: Hasher>(&self, state: &mut H) {
109 self.model.hash(state);
110 }
111}
112
113impl<V> PartialEq for View<V> {
114 fn eq(&self, other: &Self) -> bool {
115 self.model == other.model
116 }
117}
118
119impl<V> Eq for View<V> {}
120
121pub struct WeakView<V> {
122 pub(crate) model: WeakModel<V>,
123}
124
125impl<V: 'static> WeakView<V> {
126 pub fn entity_id(&self) -> EntityId {
127 self.model.entity_id
128 }
129
130 pub fn upgrade(&self) -> Option<View<V>> {
131 Entity::upgrade_from(self)
132 }
133
134 pub fn update<C, R>(
135 &self,
136 cx: &mut C,
137 f: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
138 ) -> Result<R>
139 where
140 C: VisualContext,
141 Result<C::Result<R>>: Flatten<R>,
142 {
143 let view = self.upgrade().context("error upgrading view")?;
144 Ok(view.update(cx, f)).flatten()
145 }
146}
147
148impl<V> Clone for WeakView<V> {
149 fn clone(&self) -> Self {
150 Self {
151 model: self.model.clone(),
152 }
153 }
154}
155
156impl<V> Hash for WeakView<V> {
157 fn hash<H: Hasher>(&self, state: &mut H) {
158 self.model.hash(state);
159 }
160}
161
162impl<V> PartialEq for WeakView<V> {
163 fn eq(&self, other: &Self) -> bool {
164 self.model == other.model
165 }
166}
167
168impl<V> Eq for WeakView<V> {}
169
170#[derive(Clone, Debug)]
171pub struct AnyView {
172 model: AnyModel,
173 layout: fn(&AnyView, &mut WindowContext) -> (LayoutId, AnyElement),
174 paint: fn(&AnyView, &mut AnyElement, &mut WindowContext),
175}
176
177impl AnyView {
178 pub fn downgrade(&self) -> AnyWeakView {
179 AnyWeakView {
180 model: self.model.downgrade(),
181 layout: self.layout,
182 paint: self.paint,
183 }
184 }
185
186 pub fn downcast<T: 'static>(self) -> Result<View<T>, Self> {
187 match self.model.downcast() {
188 Ok(model) => Ok(View { model }),
189 Err(model) => Err(Self {
190 model,
191 layout: self.layout,
192 paint: self.paint,
193 }),
194 }
195 }
196
197 pub fn entity_type(&self) -> TypeId {
198 self.model.entity_type
199 }
200
201 pub fn entity_id(&self) -> EntityId {
202 self.model.entity_id()
203 }
204
205 pub(crate) fn draw(
206 &self,
207 origin: Point<Pixels>,
208 available_space: Size<AvailableSpace>,
209 cx: &mut WindowContext,
210 ) {
211 cx.with_absolute_element_offset(origin, |cx| {
212 let (layout_id, mut rendered_element) = (self.layout)(self, cx);
213 cx.compute_layout(layout_id, available_space);
214 (self.paint)(self, &mut rendered_element, cx);
215 })
216 }
217}
218
219impl<V: Render> From<View<V>> for AnyView {
220 fn from(value: View<V>) -> Self {
221 AnyView {
222 model: value.model.into_any(),
223 layout: any_view::layout::<V>,
224 paint: any_view::paint,
225 }
226 }
227}
228
229impl Element for AnyView {
230 type State = Option<AnyElement>;
231
232 fn request_layout(
233 &mut self,
234 _state: Option<Self::State>,
235 cx: &mut WindowContext,
236 ) -> (LayoutId, Self::State) {
237 let (layout_id, state) = (self.layout)(self, cx);
238 (layout_id, Some(state))
239 }
240
241 fn paint(&mut self, _: Bounds<Pixels>, state: &mut Self::State, cx: &mut WindowContext) {
242 debug_assert!(
243 state.is_some(),
244 "state is None. Did you include an AnyView twice in the tree?"
245 );
246 (self.paint)(self, state.as_mut().unwrap(), cx)
247 }
248}
249
250impl<V: 'static + Render> IntoElement for View<V> {
251 type Element = View<V>;
252
253 fn element_id(&self) -> Option<ElementId> {
254 Some(ElementId::from_entity_id(self.model.entity_id))
255 }
256
257 fn into_element(self) -> Self::Element {
258 self
259 }
260}
261
262impl IntoElement for AnyView {
263 type Element = Self;
264
265 fn element_id(&self) -> Option<ElementId> {
266 Some(ElementId::from_entity_id(self.model.entity_id))
267 }
268
269 fn into_element(self) -> Self::Element {
270 self
271 }
272}
273
274pub struct AnyWeakView {
275 model: AnyWeakModel,
276 layout: fn(&AnyView, &mut WindowContext) -> (LayoutId, AnyElement),
277 paint: fn(&AnyView, &mut AnyElement, &mut WindowContext),
278}
279
280impl AnyWeakView {
281 pub fn upgrade(&self) -> Option<AnyView> {
282 let model = self.model.upgrade()?;
283 Some(AnyView {
284 model,
285 layout: self.layout,
286 paint: self.paint,
287 })
288 }
289}
290
291impl<V: 'static + Render> From<WeakView<V>> for AnyWeakView {
292 fn from(view: WeakView<V>) -> Self {
293 Self {
294 model: view.model.into(),
295 layout: any_view::layout::<V>,
296 paint: any_view::paint,
297 }
298 }
299}
300
301impl PartialEq for AnyWeakView {
302 fn eq(&self, other: &Self) -> bool {
303 self.model == other.model
304 }
305}
306
307impl std::fmt::Debug for AnyWeakView {
308 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
309 f.debug_struct("AnyWeakView")
310 .field("entity_id", &self.model.entity_id)
311 .finish_non_exhaustive()
312 }
313}
314
315mod any_view {
316 use crate::{AnyElement, AnyView, IntoElement, LayoutId, Render, WindowContext};
317
318 pub(crate) fn layout<V: 'static + Render>(
319 view: &AnyView,
320 cx: &mut WindowContext,
321 ) -> (LayoutId, AnyElement) {
322 let view = view.clone().downcast::<V>().unwrap();
323 let mut element = view.update(cx, |view, cx| view.render(cx).into_any_element());
324 let layout_id = element.request_layout(cx);
325 (layout_id, element)
326 }
327
328 pub(crate) fn paint(_view: &AnyView, element: &mut AnyElement, cx: &mut WindowContext) {
329 element.paint(cx);
330 }
331}