Pass a RenderContext to UniformList

In some cases, we need to render during layout. Previously, we were rendering with a LayoutContext in some cases, but this commit adds the ability to retrieve a render context with a given handle and we use that feature in UniformList.

Co-Authored-By: Max Brunsfeld <maxbrunsfeld@gmail.com>

crates/gpui/src/app.rs

@@ -468,6 +468,26 @@ impl TestAppContext {
         result
     }
 
+    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
+    where
+        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
+        V: View,
+    {
+        handle.update(&mut *self.cx.borrow_mut(), |view, cx| {
+            let mut render_cx = RenderContext {
+                app: cx,
+                window_id: handle.window_id(),
+                view_id: handle.id(),
+                view_type: PhantomData,
+                titlebar_height: 0.,
+                hovered_region_id: None,
+                clicked_region_id: None,
+                refreshing: false,
+            };
+            f(view, &mut render_cx)
+        })
+    }
+
     pub fn to_async(&self) -> AsyncAppContext {
         AsyncAppContext(self.cx.clone())
     }
@@ -1756,27 +1776,6 @@ impl MutableAppContext {
         )
     }
 
-    pub fn build_render_context<V: View>(
-        &mut self,
-        window_id: usize,
-        view_id: usize,
-        titlebar_height: f32,
-        hovered_region_id: Option<MouseRegionId>,
-        clicked_region_id: Option<MouseRegionId>,
-        refreshing: bool,
-    ) -> RenderContext<V> {
-        RenderContext {
-            app: self,
-            window_id,
-            view_id,
-            view_type: PhantomData,
-            titlebar_height,
-            hovered_region_id,
-            clicked_region_id,
-            refreshing,
-        }
-    }
-
     pub fn add_view<T, F>(&mut self, window_id: usize, build_view: F) -> ViewHandle<T>
     where
         T: View,
@@ -3429,13 +3428,13 @@ pub struct RenderParams {
 }
 
 pub struct RenderContext<'a, T: View> {
+    pub(crate) window_id: usize,
+    pub(crate) view_id: usize,
+    pub(crate) view_type: PhantomData<T>,
+    pub(crate) hovered_region_id: Option<MouseRegionId>,
+    pub(crate) clicked_region_id: Option<MouseRegionId>,
     pub app: &'a mut MutableAppContext,
-    window_id: usize,
-    view_id: usize,
-    view_type: PhantomData<T>,
     pub titlebar_height: f32,
-    hovered_region_id: Option<MouseRegionId>,
-    clicked_region_id: Option<MouseRegionId>,
     pub refreshing: bool,
 }
 
@@ -3587,6 +3586,16 @@ impl<V> UpgradeViewHandle for ViewContext<'_, V> {
     }
 }
 
+impl<V: View> UpgradeViewHandle for RenderContext<'_, V> {
+    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
+        self.cx.upgrade_view_handle(handle)
+    }
+
+    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
+        self.cx.upgrade_any_view_handle(handle)
+    }
+}
+
 impl<V: View> UpdateModel for ViewContext<'_, V> {
     fn update_model<T: Entity, O>(
         &mut self,

crates/gpui/src/elements/uniform_list.rs

@@ -5,7 +5,7 @@ use crate::{
         vector::{vec2f, Vector2F},
     },
     json::{self, json},
-    ElementBox,
+    ElementBox, RenderContext, View,
 };
 use json::ToJson;
 use std::{cell::RefCell, cmp, ops::Range, rc::Rc};
@@ -41,27 +41,40 @@ pub struct LayoutState {
     items: Vec<ElementBox>,
 }
 
-pub struct UniformList<F>
-where
-    F: Fn(Range<usize>, &mut Vec<ElementBox>, &mut LayoutContext),
-{
+pub struct UniformList {
     state: UniformListState,
     item_count: usize,
-    append_items: F,
+    append_items: Box<dyn Fn(Range<usize>, &mut Vec<ElementBox>, &mut LayoutContext) -> bool>,
     padding_top: f32,
     padding_bottom: f32,
     get_width_from_item: Option<usize>,
 }
 
-impl<F> UniformList<F>
-where
-    F: Fn(Range<usize>, &mut Vec<ElementBox>, &mut LayoutContext),
-{
-    pub fn new(state: UniformListState, item_count: usize, append_items: F) -> Self {
+impl UniformList {
+    pub fn new<F, V>(
+        state: UniformListState,
+        item_count: usize,
+        cx: &mut RenderContext<V>,
+        append_items: F,
+    ) -> Self
+    where
+        V: View,
+        F: 'static + Fn(&mut V, Range<usize>, &mut Vec<ElementBox>, &mut RenderContext<V>),
+    {
+        let handle = cx.handle();
         Self {
             state,
             item_count,
-            append_items,
+            append_items: Box::new(move |range, items, cx| {
+                if let Some(handle) = handle.upgrade(cx) {
+                    cx.render(&handle, |view, cx| {
+                        append_items(view, range, items, cx);
+                    });
+                    true
+                } else {
+                    false
+                }
+            }),
             padding_top: 0.,
             padding_bottom: 0.,
             get_width_from_item: None,
@@ -144,10 +157,7 @@ where
     }
 }
 
-impl<F> Element for UniformList<F>
-where
-    F: Fn(Range<usize>, &mut Vec<ElementBox>, &mut LayoutContext),
-{
+impl Element for UniformList {
     type LayoutState = LayoutState;
     type PaintState = ();
 

crates/gpui/src/presenter.rs

@@ -9,13 +9,14 @@ use crate::{
     text_layout::TextLayoutCache,
     Action, AnyModelHandle, AnyViewHandle, AnyWeakModelHandle, AssetCache, ElementBox,
     ElementStateContext, Entity, FontSystem, ModelHandle, MouseRegion, MouseRegionId, ReadModel,
-    ReadView, RenderParams, Scene, UpgradeModelHandle, UpgradeViewHandle, View, ViewHandle,
-    WeakModelHandle, WeakViewHandle,
+    ReadView, RenderContext, RenderParams, Scene, UpgradeModelHandle, UpgradeViewHandle, View,
+    ViewHandle, WeakModelHandle, WeakViewHandle,
 };
 use pathfinder_geometry::vector::{vec2f, Vector2F};
 use serde_json::json;
 use std::{
     collections::{HashMap, HashSet},
+    marker::PhantomData,
     ops::{Deref, DerefMut},
     sync::Arc,
 };
@@ -172,12 +173,15 @@ impl Presenter {
         LayoutContext {
             rendered_views: &mut self.rendered_views,
             parents: &mut self.parents,
-            refreshing,
             font_cache: &self.font_cache,
             font_system: cx.platform().fonts(),
             text_layout_cache: &self.text_layout_cache,
             asset_cache: &self.asset_cache,
             view_stack: Vec::new(),
+            refreshing,
+            hovered_region_id: self.hovered_region_id,
+            clicked_region_id: self.clicked_region.as_ref().map(MouseRegion::id),
+            titlebar_height: self.titlebar_height,
             app: cx,
         }
     }
@@ -342,12 +346,15 @@ pub struct LayoutContext<'a> {
     rendered_views: &'a mut HashMap<usize, ElementBox>,
     parents: &'a mut HashMap<usize, usize>,
     view_stack: Vec<usize>,
-    pub refreshing: bool,
     pub font_cache: &'a Arc<FontCache>,
     pub font_system: Arc<dyn FontSystem>,
     pub text_layout_cache: &'a TextLayoutCache,
     pub asset_cache: &'a AssetCache,
     pub app: &'a mut MutableAppContext,
+    pub refreshing: bool,
+    titlebar_height: f32,
+    hovered_region_id: Option<MouseRegionId>,
+    clicked_region_id: Option<MouseRegionId>,
 }
 
 impl<'a> LayoutContext<'a> {
@@ -362,6 +369,26 @@ impl<'a> LayoutContext<'a> {
         self.view_stack.pop();
         size
     }
+
+    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
+    where
+        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
+        V: View,
+    {
+        handle.update(self.app, |view, cx| {
+            let mut render_cx = RenderContext {
+                app: cx,
+                window_id: handle.window_id(),
+                view_id: handle.id(),
+                view_type: PhantomData,
+                titlebar_height: self.titlebar_height,
+                hovered_region_id: self.hovered_region_id,
+                clicked_region_id: self.clicked_region_id,
+                refreshing: self.refreshing,
+            };
+            f(view, &mut render_cx)
+        })
+    }
 }
 
 impl<'a> Deref for LayoutContext<'a> {

crates/gpui/src/views/select.rs

@@ -123,7 +123,6 @@ impl View for Select {
             .boxed(),
         );
         if self.is_open {
-            let handle = self.handle.clone();
             result.add_child(
                 Overlay::new(
                     Container::new(
@@ -131,9 +130,8 @@ impl View for Select {
                             UniformList::new(
                                 self.list_state.clone(),
                                 self.item_count,
-                                move |mut range, items, cx| {
-                                    let handle = handle.upgrade(cx).unwrap();
-                                    let this = handle.read(cx);
+                                cx,
+                                move |this, mut range, items, cx| {
                                     let selected_item_ix = this.selected_item_ix;
                                     range.end = range.end.min(this.item_count);
                                     items.extend(range.map(|ix| {
@@ -141,7 +139,7 @@ impl View for Select {
                                             ix,
                                             cx,
                                             |mouse_state, cx| {
-                                                (handle.read(cx).render_item)(
+                                                (this.render_item)(
                                                     ix,
                                                     if ix == selected_item_ix {
                                                         ItemType::Selected