Replace lazy_static with OnceLock

Author: emilk

Cargo.lock

@@ -131,10 +131,10 @@ half = "2.3.1"
 hyper = "0.14"
 image = { version = "0.24", default-features = false }
 indent = "0.1"
-infer = "0.15" # infer MIME type by checking the magic number signature
+infer = "0.15"                                                     # infer MIME type by checking the magic number signature
 itertools = "0.11"
 js-sys = "0.3"
-lazy_static = "1.4"
+# No lazy_static - use `std::sync::OnceLock` or `once_cell` instead
 lz4_flex = "0.11"
 log = "0.4"
 log-once = "0.4"

Cargo.toml

@@ -37,7 +37,6 @@ egui_tiles.workspace = true
 glam.workspace = true
 half.workspace = true
 itertools.workspace = true
-lazy_static.workspace = true
 macaw.workspace = true
 ndarray.workspace = true
 nohash-hasher.workspace = true

crates/re_viewer_context/Cargo.toml

@@ -1,7 +1,6 @@
 use std::{collections::BTreeMap, sync::Arc};
 
 use ahash::HashMap;
-use lazy_static::lazy_static;
 use nohash_hasher::IntSet;
 
 use re_arrow_store::LatestAtQuery;
@@ -14,6 +13,8 @@ use re_types::datatypes::{AnnotationInfo, ClassDescription, ClassId, KeypointId}
 use super::{auto_color, ViewerContext};
 use crate::DefaultColor;
 
+const MISSING_ROW_ID: RowId = RowId::ZERO;
+
 #[derive(Clone, Debug)]
 pub struct Annotations {
     row_id: RowId,
@@ -29,6 +30,14 @@ impl Annotations {
         }
     }
 
+    /// Fast access to an [`Arc`] sharing the same [`Annotations::missing`] instance.
+    pub fn missing_arc() -> Arc<Annotations> {
+        use std::sync::OnceLock;
+        static CELL: OnceLock<Arc<Annotations>> = OnceLock::new();
+        CELL.get_or_init(|| Arc::new(Annotations::missing()))
+            .clone()
+    }
+
     pub fn try_from_view(view: &ArchetypeView<AnnotationContext>) -> Option<Self> {
         re_tracing::profile_function!();
 
@@ -273,7 +282,7 @@ impl AnnotationMap {
     }
 
     // Search through the all prefixes of this entity path until we find a
-    // matching annotation. If we find nothing return the default [`MISSING_ANNOTATIONS`].
+    // matching annotation. If we find nothing return the default [`Annotations::missing_arc`].
     pub fn find(&self, entity_path: &EntityPath) -> Arc<Annotations> {
         let mut next_parent = Some(entity_path.clone());
         while let Some(parent) = next_parent {
@@ -285,14 +294,6 @@ impl AnnotationMap {
         }
 
         // Otherwise return the missing legend
-        Arc::clone(&MISSING_ANNOTATIONS)
+        Annotations::missing_arc()
     }
 }
-
-// ---
-
-const MISSING_ROW_ID: RowId = RowId::ZERO;
-
-lazy_static! {
-    pub static ref MISSING_ANNOTATIONS: Arc<Annotations> = Arc::new(Annotations::missing());
-}

crates/re_viewer_context/src/annotations.rs

@@ -24,7 +24,6 @@ pub mod gpu_bridge;
 
 pub use annotations::{
     AnnotationMap, Annotations, ResolvedAnnotationInfo, ResolvedAnnotationInfos,
-    MISSING_ANNOTATIONS,
 };
 pub use app_options::AppOptions;
 pub use blueprint_id::{DataQueryId, SpaceViewId};

crates/re_viewer_context/src/lib.rs

@@ -1,4 +1,3 @@
-use lazy_static::lazy_static;
 use nohash_hasher::IntMap;
 
 use re_log_types::EntityPathHash;
@@ -39,11 +38,6 @@ pub struct SpaceViewOutlineMasks {
     pub instances: ahash::HashMap<InstanceKey, OutlineMaskPreference>,
 }
 
-lazy_static! {
-    static ref SPACEVIEW_OUTLINE_MASK_NONE: SpaceViewOutlineMasks =
-        SpaceViewOutlineMasks::default();
-}
-
 impl SpaceViewOutlineMasks {
     pub fn index_outline_mask(&self, instance_key: InstanceKey) -> OutlineMaskPreference {
         self.instances
@@ -72,9 +66,12 @@ impl SpaceViewHighlights {
     }
 
     pub fn entity_outline_mask(&self, entity_path_hash: EntityPathHash) -> &SpaceViewOutlineMasks {
+        use std::sync::OnceLock;
+        static CELL: OnceLock<SpaceViewOutlineMasks> = OnceLock::new();
+
         self.outlines_masks
             .get(&entity_path_hash)
-            .unwrap_or(&SPACEVIEW_OUTLINE_MASK_NONE)
+            .unwrap_or_else(|| CELL.get_or_init(SpaceViewOutlineMasks::default))
     }
 
     pub fn any_outlines(&self) -> bool {