tenant.openagents/omega

1use crate::{
2    AnyElement, AnyEntity, AnyWeakEntity, App, Bounds, ContentMask, Context, Element, ElementId,
3    Entity, EntityId, GlobalElementId, InspectorElementId, IntoElement, LayoutId, PaintIndex,
4    Pixels, PrepaintStateIndex, Render, RenderOnce, Style, StyleRefinement, TextStyle, WeakEntity,
5};
6use crate::{Empty, Window};
7use anyhow::Result;
8use collections::FxHashSet;
9use refineable::Refineable;
10use std::mem;
11use std::{any::TypeId, fmt, ops::Range};
12
13/// A dynamically-typed view handle that can be downcast to a specific `Entity<V>`.
14///
15/// This is the type-erased counterpart to [`ViewElement`]: it holds an entity plus
16/// a function pointer to its render, and is itself a [`View`], so embedding it as an
17/// element goes through the same [`ViewElement`] machinery as any other view.
18#[derive(Clone, Debug)]
19pub struct AnyView {
20    entity: AnyEntity,
21    render: fn(&AnyView, &mut Window, &mut App) -> AnyElement,
22}
23
24impl<V: Render> From<Entity<V>> for AnyView {
25    fn from(value: Entity<V>) -> Self {
26        AnyView {
27            entity: value.into_any(),
28            render: any_view::render::<V>,
29        }
30    }
31}
32
33impl AnyView {
34    /// Embed this view as a cached [`ViewElement`] laid out at `style`.
35    ///
36    /// The rendered subtree is recycled from the previous frame unless
37    /// [Context::notify] was called on the backing entity since it was rendered
38    /// (or [Window::refresh] is called, which ignores caching).
39    pub fn cached(self, style: StyleRefinement) -> ViewElement<AnyView> {
40        ViewElement::new(self).cached(style)
41    }
42
43    /// Convert this to a weak handle.
44    pub fn downgrade(&self) -> AnyWeakView {
45        AnyWeakView {
46            entity: self.entity.downgrade(),
47            render: self.render,
48        }
49    }
50
51    /// Convert this to a [Entity] of a specific type.
52    /// If this handle does not contain a view of the specified type, returns itself in an `Err` variant.
53    pub fn downcast<T: 'static>(self) -> Result<Entity<T>, Self> {
54        match self.entity.downcast() {
55            Ok(entity) => Ok(entity),
56            Err(entity) => Err(Self {
57                entity,
58                render: self.render,
59            }),
60        }
61    }
62
63    /// Gets the [TypeId] of the underlying view.
64    pub fn entity_type(&self) -> TypeId {
65        self.entity.entity_type
66    }
67
68    /// The [`EntityId`] of this view.
69    pub fn entity_id(&self) -> EntityId {
70        self.entity.entity_id()
71    }
72}
73
74impl PartialEq for AnyView {
75    fn eq(&self, other: &Self) -> bool {
76        self.entity == other.entity
77    }
78}
79
80impl Eq for AnyView {}
81
82/// `AnyView` is the type-erased [`View`]: its `render` is a function pointer rather
83/// than a concrete type, but it participates in the reactive graph exactly like any
84/// other view via [`ViewElement`].
85impl View for AnyView {
86    fn entity_id(&self) -> Option<EntityId> {
87        Some(self.entity.entity_id())
88    }
89
90    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
91        (self.render)(&self, window, cx)
92    }
93}
94
95impl<V: 'static + Render> IntoElement for Entity<V> {
96    type Element = ViewElement<Entity<V>>;
97
98    fn into_element(self) -> Self::Element {
99        ViewElement::new(self)
100    }
101}
102
103impl IntoElement for AnyView {
104    type Element = ViewElement<AnyView>;
105
106    fn into_element(self) -> Self::Element {
107        ViewElement::new(self)
108    }
109}
110
111/// A weak, dynamically-typed view handle.
112pub struct AnyWeakView {
113    entity: AnyWeakEntity,
114    render: fn(&AnyView, &mut Window, &mut App) -> AnyElement,
115}
116
117impl AnyWeakView {
118    /// Upgrade to a strong `AnyView` handle, if the view is still alive.
119    pub fn upgrade(&self) -> Option<AnyView> {
120        let entity = self.entity.upgrade()?;
121        Some(AnyView {
122            entity,
123            render: self.render,
124        })
125    }
126}
127
128impl<V: 'static + Render> From<WeakEntity<V>> for AnyWeakView {
129    fn from(view: WeakEntity<V>) -> Self {
130        AnyWeakView {
131            entity: view.into(),
132            render: any_view::render::<V>,
133        }
134    }
135}
136
137impl PartialEq for AnyWeakView {
138    fn eq(&self, other: &Self) -> bool {
139        self.entity == other.entity
140    }
141}
142
143impl std::fmt::Debug for AnyWeakView {
144    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
145        f.debug_struct("AnyWeakView")
146            .field("entity_id", &self.entity.entity_id)
147            .finish_non_exhaustive()
148    }
149}
150
151mod any_view {
152    use crate::{AnyElement, AnyView, App, IntoElement, Render, Window};
153
154    pub(crate) fn render<V: 'static + Render>(
155        view: &AnyView,
156        window: &mut Window,
157        cx: &mut App,
158    ) -> AnyElement {
159        let view = view.clone().downcast::<V>().unwrap();
160        // Record the view's Render type name so the accessibility debug dump can
161        // attribute nodes to the view that produced them.
162        #[cfg(debug_assertions)]
163        window
164            .a11y
165            .view_type_names
166            .insert(view.entity_id(), std::any::type_name::<V>());
167        view.update(cx, |view, cx| view.render(window, cx).into_any_element())
168    }
169}
170
171/// A renderable that participates in GPUI's reactive graph — the unifying model
172/// behind [`Render`] and [`RenderOnce`].
173///
174/// When `entity_id()` returns `Some`, that id becomes the view's identity: it gets
175/// a unique element-id space (so internal `use_state` / `.id(..)` never collide
176/// across siblings) and `cx.notify()` on that entity re-renders only this view's
177/// subtree. `None` behaves like a stateless component.
178///
179/// You rarely implement `View` directly. `Entity<T: Render>` and any `T: RenderOnce`
180/// get a blanket impl below; implement it by hand only when a component needs both
181/// parent-supplied props *and* a backing entity for identity.
182pub trait View: 'static + Sized {
183    /// This view's identity, if it has one. A view typically holds the backing
184    /// entity as a field and returns its [`EntityId`] here.
185    ///
186    /// The id becomes this view's [`ElementId`], so two views keyed on the same
187    /// entity must not be rendered at the same position in the element tree
188    /// (e.g. as siblings under the same parent): their internal element state
189    /// (`use_state`, scroll offsets, etc.) would silently collide. Nesting is
190    /// fine — the id is scoped by the parent path.
191    fn entity_id(&self) -> Option<EntityId>;
192
193    /// Render this view into an element tree, consuming `self`.
194    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement;
195}
196
197/// A stateless component (`RenderOnce`) is a `View` with no identity.
198impl<T: RenderOnce> View for T {
199    fn entity_id(&self) -> Option<EntityId> {
200        None
201    }
202
203    #[inline]
204    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
205        RenderOnce::render(self, window, cx)
206    }
207}
208
209/// An entity that renders itself (`Render`) is a `View` keyed on its own id.
210impl<T: Render> View for Entity<T> {
211    fn entity_id(&self) -> Option<EntityId> {
212        Some(Entity::entity_id(self))
213    }
214
215    #[inline]
216    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
217        self.update(cx, |this, cx| {
218            Render::render(this, window, cx).into_any_element()
219        })
220    }
221}
222
223impl<T: Render> Entity<T> {
224    /// Embed this entity as a cached [`ViewElement`] laid out at `style`.
225    ///
226    /// The rendered subtree is reused until the entity is notified (or the
227    /// cached bounds / text style change). Caching requires a definite size:
228    /// a cached view is laid out from `style` and is *not* measured from its
229    /// contents. Use [`ViewElement::new`] (or `.child(entity)`) for the
230    /// uncached case.
231    #[track_caller]
232    pub fn cached(self, style: StyleRefinement) -> ViewElement<Entity<T>> {
233        ViewElement::new(self).cached(style)
234    }
235}
236
237/// The element type for [`View`] implementations. Wraps a `View` and hooks it
238/// into layout, prepaint, and paint. Constructed via [`ViewElement::new`].
239#[doc(hidden)]
240pub struct ViewElement<V: View> {
241    view: Option<V>,
242    entity_id: Option<EntityId>,
243    cached_style: Option<StyleRefinement>,
244    #[cfg(debug_assertions)]
245    source: &'static core::panic::Location<'static>,
246}
247
248impl<V: View> ViewElement<V> {
249    /// Wrap a [`View`] as an element.
250    #[track_caller]
251    pub fn new(view: V) -> Self {
252        let entity_id = view.entity_id();
253        ViewElement {
254            entity_id,
255            cached_style: None,
256            view: Some(view),
257            #[cfg(debug_assertions)]
258            source: core::panic::Location::caller(),
259        }
260    }
261
262    /// Enable caching of this view's rendered subtree, laid out at `style`.
263    /// The composer supplies the layout style because caching skips rendering
264    /// the contents to measure them.
265    ///
266    /// Crate-private on purpose: caching is only sound for entity-backed views,
267    /// where [`Context::notify`] is the contract that busts the cache. A stateless
268    /// view has no such contract, so a frozen subtree could never be invalidated.
269    /// Reach this through [`Entity::cached`] or [`AnyView::cached`], which are
270    /// entity-backed by construction.
271    pub(crate) fn cached(mut self, style: StyleRefinement) -> Self {
272        self.cached_style = Some(style);
273        self
274    }
275}
276
277impl<V: View> IntoElement for ViewElement<V> {
278    type Element = Self;
279
280    fn into_element(self) -> Self::Element {
281        self
282    }
283}
284
285struct ViewElementState {
286    prepaint_range: Range<PrepaintStateIndex>,
287    paint_range: Range<PaintIndex>,
288    cache_key: ViewElementCacheKey,
289    accessed_entities: FxHashSet<EntityId>,
290}
291
292struct ViewElementCacheKey {
293    bounds: Bounds<Pixels>,
294    content_mask: ContentMask<Pixels>,
295    text_style: TextStyle,
296}
297
298impl<V: View> Element for ViewElement<V> {
299    type RequestLayoutState = Option<AnyElement>;
300    type PrepaintState = Option<AnyElement>;
301
302    fn id(&self) -> Option<ElementId> {
303        self.entity_id.map(ElementId::View)
304    }
305
306    fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
307        #[cfg(debug_assertions)]
308        return Some(self.source);
309
310        #[cfg(not(debug_assertions))]
311        return None;
312    }
313
314    fn request_layout(
315        &mut self,
316        _id: Option<&GlobalElementId>,
317        _inspector_id: Option<&InspectorElementId>,
318        window: &mut Window,
319        cx: &mut App,
320    ) -> (LayoutId, Self::RequestLayoutState) {
321        if let Some(entity_id) = self.entity_id {
322            // Stateful path: create a reactive boundary.
323            window.with_rendered_view(entity_id, |window| {
324                let caching_disabled = window.is_inspector_picking(cx);
325                match self.cached_style.as_ref() {
326                    Some(style) if !caching_disabled => {
327                        let mut root_style = Style::default();
328                        root_style.refine(style);
329                        let layout_id = window.request_layout(root_style, None, cx);
330                        (layout_id, None)
331                    }
332                    _ => {
333                        let mut element = self
334                            .view
335                            .take()
336                            .unwrap()
337                            .render(window, cx)
338                            .into_any_element();
339                        let layout_id = element.request_layout(window, cx);
340                        (layout_id, Some(element))
341                    }
342                }
343            })
344        } else {
345            // Stateless path: isolate subtree via type name (no entity identity).
346            window.with_id(
347                ElementId::Name(std::any::type_name::<V>().into()),
348                |window| {
349                    let mut element = self
350                        .view
351                        .take()
352                        .unwrap()
353                        .render(window, cx)
354                        .into_any_element();
355                    let layout_id = element.request_layout(window, cx);
356                    (layout_id, Some(element))
357                },
358            )
359        }
360    }
361
362    fn prepaint(
363        &mut self,
364        global_id: Option<&GlobalElementId>,
365        _inspector_id: Option<&InspectorElementId>,
366        bounds: Bounds<Pixels>,
367        element: &mut Self::RequestLayoutState,
368        window: &mut Window,
369        cx: &mut App,
370    ) -> Option<AnyElement> {
371        if let Some(entity_id) = self.entity_id {
372            // Stateful path.
373            window.set_view_id(entity_id);
374            window.with_rendered_view(entity_id, |window| {
375                if let Some(mut element) = element.take() {
376                    element.prepaint(window, cx);
377                    return Some(element);
378                }
379
380                window.with_element_state::<ViewElementState, _>(
381                    global_id.unwrap(),
382                    |element_state, window| {
383                        let content_mask = window.content_mask();
384                        let text_style = window.text_style();
385
386                        if let Some(mut element_state) = element_state
387                            && element_state.cache_key.bounds == bounds
388                            && element_state.cache_key.content_mask == content_mask
389                            && element_state.cache_key.text_style == text_style
390                            && !window.dirty_views.contains(&entity_id)
391                            && !window.refreshing
392                        {
393                            let prepaint_start = window.prepaint_index();
394                            window.reuse_prepaint(element_state.prepaint_range.clone());
395                            cx.entities
396                                .extend_accessed(&element_state.accessed_entities);
397                            let prepaint_end = window.prepaint_index();
398                            element_state.prepaint_range = prepaint_start..prepaint_end;
399
400                            return (None, element_state);
401                        }
402
403                        let refreshing = mem::replace(&mut window.refreshing, true);
404                        let prepaint_start = window.prepaint_index();
405                        let (mut element, accessed_entities) = cx.detect_accessed_entities(|cx| {
406                            let mut element = self
407                                .view
408                                .take()
409                                .unwrap()
410                                .render(window, cx)
411                                .into_any_element();
412                            element.layout_as_root(bounds.size.into(), window, cx);
413                            element.prepaint_at(bounds.origin, window, cx);
414                            element
415                        });
416
417                        let prepaint_end = window.prepaint_index();
418                        window.refreshing = refreshing;
419
420                        (
421                            Some(element),
422                            ViewElementState {
423                                accessed_entities,
424                                prepaint_range: prepaint_start..prepaint_end,
425                                paint_range: PaintIndex::default()..PaintIndex::default(),
426                                cache_key: ViewElementCacheKey {
427                                    bounds,
428                                    content_mask,
429                                    text_style,
430                                },
431                            },
432                        )
433                    },
434                )
435            })
436        } else {
437            // Stateless path: just prepaint the element.
438            window.with_id(
439                ElementId::Name(std::any::type_name::<V>().into()),
440                |window| {
441                    element.as_mut().unwrap().prepaint(window, cx);
442                },
443            );
444            Some(element.take().unwrap())
445        }
446    }
447
448    fn paint(
449        &mut self,
450        global_id: Option<&GlobalElementId>,
451        _inspector_id: Option<&InspectorElementId>,
452        _bounds: Bounds<Pixels>,
453        _request_layout: &mut Self::RequestLayoutState,
454        element: &mut Self::PrepaintState,
455        window: &mut Window,
456        cx: &mut App,
457    ) {
458        if let Some(entity_id) = self.entity_id {
459            // Stateful path.
460            window.with_rendered_view(entity_id, |window| {
461                let caching_disabled = window.is_inspector_picking(cx);
462                if self.cached_style.is_some() && !caching_disabled {
463                    window.with_element_state::<ViewElementState, _>(
464                        global_id.unwrap(),
465                        |element_state, window| {
466                            let mut element_state = element_state.unwrap();
467
468                            let paint_start = window.paint_index();
469
470                            if let Some(element) = element {
471                                let refreshing = mem::replace(&mut window.refreshing, true);
472                                element.paint(window, cx);
473                                window.refreshing = refreshing;
474                            } else {
475                                window.reuse_paint(element_state.paint_range.clone());
476                            }
477
478                            let paint_end = window.paint_index();
479                            element_state.paint_range = paint_start..paint_end;
480
481                            ((), element_state)
482                        },
483                    )
484                } else {
485                    element.as_mut().unwrap().paint(window, cx);
486                }
487            });
488        } else {
489            // Stateless path: just paint the element.
490            window.with_id(
491                ElementId::Name(std::any::type_name::<V>().into()),
492                |window| {
493                    element.as_mut().unwrap().paint(window, cx);
494                },
495            );
496        }
497    }
498}
499
500/// A view that renders nothing
501pub struct EmptyView;
502
503impl Render for EmptyView {
504    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
505        Empty
506    }
507}
508