Make Caches non-mut

crates/re_data_ui/src/image.rs

@@ -26,7 +26,8 @@ impl EntityDataUi for Tensor {
     ) {
         re_tracing::profile_function!();
 
-        match ctx.cache.entry::<TensorDecodeCache>().entry(self.clone()) {
+        let decoded = ctx.cache.entry::<TensorDecodeCache>().entry(self.clone());
+        match decoded {
             Ok(decoded) => {
                 let annotations = crate::annotations(ctx, query, entity_path);
                 tensor_ui(

crates/re_space_view_spatial/src/scene/parts/images.rs

@@ -43,13 +43,13 @@ fn to_textured_rect(
     let Some([height, width, _]) = tensor.image_height_width_channels() else { return None; };
 
     let debug_name = ent_path.to_string();
-    let tensor_stats = ctx.cache.entry::<TensorStatsCache>().entry(tensor);
+    let tensor_stats = *ctx.cache.entry::<TensorStatsCache>().entry(tensor);
 
     match gpu_bridge::tensor_to_gpu(
         ctx.render_ctx,
         &debug_name,
         tensor,
-        tensor_stats,
+        &tensor_stats,
         annotations,
     ) {
         Ok(colormapped_texture) => {

crates/re_viewer_context/Cargo.toml

@@ -39,6 +39,7 @@ lazy_static.workspace = true
 macaw.workspace = true
 ndarray.workspace = true
 nohash-hasher.workspace = true
+parking_lot.workspace = true
 serde = "1"
 slotmap.workspace = true
 thiserror.workspace = true

crates/re_viewer_context/src/caches.rs

@@ -1,38 +1,42 @@
+use std::any::{Any, TypeId};
+
 use ahash::HashMap;
-use std::any::Any;
+use parking_lot::Mutex;
 
 /// Does memoization of different objects for the immediate mode UI.
 #[derive(Default)]
-pub struct Caches(HashMap<std::any::TypeId, Box<dyn Cache>>);
+pub struct Caches(Mutex<HashMap<TypeId, Box<dyn Cache>>>);
 
 impl Caches {
     /// Call once per frame to potentially flush the cache(s).
-    pub fn begin_frame(&mut self) {
-        for cache in self.0.values_mut() {
+    pub fn begin_frame(&self) {
+        re_tracing::profile_function!();
+        for cache in self.0.lock().values_mut() {
             cache.begin_frame();
         }
     }
 
     /// Attempt to free up memory.
-    pub fn purge_memory(&mut self) {
-        for cache in self.0.values_mut() {
+    pub fn purge_memory(&self) {
+        re_tracing::profile_function!();
+        for cache in self.0.lock().values_mut() {
             cache.purge_memory();
         }
     }
 
     /// Retrieves a cache for reading and writing.
     ///
     /// Adds the cache lazily if it wasn't already there.
-    pub fn entry<T: Cache + Default>(&mut self) -> &mut T {
-        let cache = self
-            .0
-            .entry(std::any::TypeId::of::<T>())
-            .or_insert(Box::<T>::default());
-
-        cache
-            .as_any_mut()
-            .downcast_mut::<T>()
-            .expect("Downcast failed, this indicates a bug in how `Caches` adds new cache types.")
+    pub fn entry<C: Cache + Default>(&self) -> parking_lot::MappedMutexGuard<'_, C> {
+        parking_lot::MutexGuard::map(self.0.lock(), |map| {
+            map.entry(TypeId::of::<C>())
+                .or_insert(Box::<C>::default())
+                .as_any_mut()
+                .downcast_mut::<C>()
+                .expect(
+                    "Downcast failed, this indicates a bug in how `Caches` adds new cache types.",
+                )
+        })
     }
 }
 

crates/re_viewer_context/src/viewer_context.rs

@@ -13,7 +13,7 @@ pub struct ViewerContext<'a> {
     /// Things that need caching and are shared across the whole viewer.
     ///
     /// Use this only for things that you expected be shared across different panels and/or space views.
-    pub cache: &'a mut Caches,
+    pub cache: &'a Caches,
 
     /// How to display components.
     pub component_ui_registry: &'a ComponentUiRegistry,

crates/re_viewport/src/view_tensor/ui.rs

@@ -178,11 +178,11 @@ fn paint_tensor_slice(
 ) -> anyhow::Result<(egui::Response, egui::Painter, egui::Rect)> {
     re_tracing::profile_function!();
 
-    let tensor_stats = ctx.cache.entry::<TensorStatsCache>().entry(tensor);
+    let tensor_stats = *ctx.cache.entry::<TensorStatsCache>().entry(tensor);
     let colormapped_texture = super::tensor_slice_to_gpu::colormapped_texture(
         ctx.render_ctx,
         tensor,
-        tensor_stats,
+        &tensor_stats,
         state,
     )?;
     let [width, height] = colormapped_texture.texture.width_height();