Replace lazy_static with OnceLock

Ralith · Apr 24, 2024 · 0e3690a · 0e3690a
1 parent 1dc0b1b
commit 0e3690a
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Showing 2 changed files with 172 additions and 104 deletions.
diff --git a/common/src/cursor.rs b/common/src/cursor.rs
@@ -1,8 +1,7 @@
 use crate::dodeca::{Side, Vertex, SIDE_COUNT};
 use crate::graph::{Graph, NodeId};
 use crate::node::ChunkId;
-
-use lazy_static::lazy_static;
+use std::sync::OnceLock;
 
 /// Navigates the cubic dual of a graph
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
@@ -28,9 +27,9 @@ impl Cursor {
         // in both the dodecahedron sharing the face unique to the new vertex and that sharing the
         // face that the new vertex isn't incident to.
         let (a, b, c) = (self.a, self.b, self.c);
-        let a_prime = NEIGHBORS[a as usize][b as usize][c as usize].unwrap();
-        let b_prime = NEIGHBORS[b as usize][a as usize][c as usize].unwrap();
-        let c_prime = NEIGHBORS[c as usize][b as usize][a as usize].unwrap();
+        let a_prime = neighbors_static()[a as usize][b as usize][c as usize].unwrap();
+        let b_prime = neighbors_static()[b as usize][a as usize][c as usize].unwrap();
+        let c_prime = neighbors_static()[c as usize][b as usize][a as usize].unwrap();
         use Dir::*;
         let (sides, neighbor) = match dir {
             Left => ((a, b, c_prime), c),
@@ -103,9 +102,10 @@ impl std::ops::Neg for Dir {
     }
 }
 
-lazy_static! {
-    /// Maps every (A, B, C) sharing a vertex to A', the side that shares edges with B and C but not A
-    static ref NEIGHBORS: [[[Option<Side>; SIDE_COUNT]; SIDE_COUNT]; SIDE_COUNT] = {
+/// Maps every (A, B, C) sharing a vertex to A', the side that shares edges with B and C but not A
+fn neighbors_static() -> &'static [[[Option<Side>; SIDE_COUNT]; SIDE_COUNT]; SIDE_COUNT] {
+    static LOCK: OnceLock<[[[Option<Side>; SIDE_COUNT]; SIDE_COUNT]; SIDE_COUNT]> = OnceLock::new();
+    LOCK.get_or_init(|| {
         let mut result = [[[None; SIDE_COUNT]; SIDE_COUNT]; SIDE_COUNT];
         for a in Side::iter() {
             for b in Side::iter() {
@@ -114,19 +114,20 @@ lazy_static! {
                         if s == a || s == b || s == c {
                             continue;
                         }
-                        let (opposite, shared) = match (s.adjacent_to(a), s.adjacent_to(b), s.adjacent_to(c)) {
-                            (false, true, true) => (a, (b, c)),
-                            (true, false, true) => (b, (a, c)),
-                            (true, true, false) => (c, (a, b)),
-                            _ => continue,
-                        };
+                        let (opposite, shared) =
+                            match (s.adjacent_to(a), s.adjacent_to(b), s.adjacent_to(c)) {
+                                (false, true, true) => (a, (b, c)),
+                                (true, false, true) => (b, (a, c)),
+                                (true, true, false) => (c, (a, b)),
+                                _ => continue,
+                            };
                         result[opposite as usize][shared.0 as usize][shared.1 as usize] = Some(s);
                     }
                 }
             }
         }
         result
-    };
+    })
 }
 
 #[cfg(test)]
@@ -139,8 +140,8 @@ mod tests {
         for v in Vertex::iter() {
             let [a, b, c] = v.canonical_sides();
             assert_eq!(
-                NEIGHBORS[a as usize][b as usize][c as usize],
-                NEIGHBORS[a as usize][c as usize][b as usize]
+                neighbors_static()[a as usize][b as usize][c as usize],
+                neighbors_static()[a as usize][c as usize][b as usize]
             );
         }
     }