Remove SlotStorage and only require Clone for graph data.

plexus/Cargo.toml

@@ -55,7 +55,6 @@ decorum = "^0.3.1"
 derivative = "^2.1.1"
 itertools = "^0.9.0"
 num = "^0.3.0"
-slotmap = "^0.4.0"
 smallvec = "^1.0.0"
 thiserror = "^1.0.3"
 typenum = "^1.10.0"

plexus/src/entity/mod.rs

@@ -28,7 +28,7 @@ pub trait Lifetime {}
 #[cfg(all(nightly, feature = "unstable"))]
 impl<T> Lifetime for T {}
 
-pub trait Entity: Copy + Lifetime + Sized {
+pub trait Entity: Lifetime + Sized {
     type Key: Key;
     type Storage: Default + Dispatch<Self> + Storage<Self>;
 }

plexus/src/entity/storage/mod.rs

@@ -1,12 +1,10 @@
 mod hash;
-mod slot;
 
 use std::hash::Hash;
 
 use crate::entity::{Entity, Payload};
 
 pub use crate::entity::storage::hash::HashStorage;
-pub use crate::entity::storage::slot::SlotStorage;
 
 pub mod prelude {
     pub use crate::entity::storage::{Enumerate, Get, Insert, InsertWithKey, Remove};

plexus/src/graph/data.rs

@@ -3,12 +3,6 @@ use crate::entity::Lifetime;
 
 pub type Data<M> = <M as Parametric>::Data;
 
-pub trait EntityData: Copy + Lifetime {}
-
-impl<T> EntityData for T where T: Copy + Lifetime {}
-
-// TODO: Require `Clone` instead of `Copy` once non-`Copy` types are supported
-//       by the slotmap crate. See https://github.com/orlp/slotmap/issues/27
 /// Graph data.
 ///
 /// Specifies the types used to represent data in vertices, arcs, edges, and
@@ -71,10 +65,10 @@ impl<T> EntityData for T where T: Copy + Lifetime {}
 /// [`AsPosition`]: crate::geometry::AsPosition
 /// [`MeshGraph`]: crate::graph::MeshGraph
 pub trait GraphData: Lifetime + Sized {
-    type Vertex: EntityData;
-    type Arc: EntityData + Default;
-    type Edge: EntityData + Default;
-    type Face: EntityData + Default;
+    type Vertex: Clone + Lifetime;
+    type Arc: Clone + Default + Lifetime;
+    type Edge: Clone + Default + Lifetime;
+    type Face: Clone + Default + Lifetime;
 }
 
 impl GraphData for () {
@@ -86,7 +80,7 @@ impl GraphData for () {
 
 impl<T> GraphData for (T, T)
 where
-    T: EntityData,
+    T: Clone + Lifetime,
 {
     type Vertex = Self;
     type Arc = ();
@@ -96,7 +90,7 @@ where
 
 impl<T> GraphData for (T, T, T)
 where
-    T: EntityData,
+    T: Clone + Lifetime,
 {
     type Vertex = Self;
     type Arc = ();
@@ -106,7 +100,7 @@ where
 
 impl<T> GraphData for [T; 2]
 where
-    T: EntityData,
+    T: Clone + Lifetime,
 {
     type Vertex = Self;
     type Arc = ();
@@ -116,7 +110,7 @@ where
 
 impl<T> GraphData for [T; 3]
 where
-    T: EntityData,
+    T: Clone + Lifetime,
 {
     type Vertex = Self;
     type Arc = ();

plexus/src/graph/edge.rs

@@ -44,7 +44,7 @@ where
 // reason, `Arc` has no fields representing its source and destination vertices
 // nor its opposite arc; such fields would be redundant.
 /// Arc entity.
-#[derivative(Clone, Copy, Debug, Hash)]
+#[derivative(Debug, Hash)]
 #[derive(Derivative)]
 pub struct Arc<G>
 where
@@ -738,13 +738,13 @@ where
     pub fn split_at_midpoint(self) -> VertexView<&'a mut M>
     where
         G: EdgeMidpoint,
-        G::Vertex: AsPositionMut,
+        G::Vertex: AsPositionMut + Clone,
     {
-        let mut geometry = self.source_vertex().data;
+        let mut data = self.source_vertex().get().clone();
         let midpoint = self.midpoint();
         self.split_with(move || {
-            *geometry.as_position_mut() = midpoint;
-            geometry
+            *data.as_position_mut() = midpoint;
+            data
         })
     }
 
@@ -1214,7 +1214,7 @@ where
 }
 
 /// Edge entity.
-#[derivative(Clone, Copy, Debug, Hash)]
+#[derivative(Debug, Hash)]
 #[derive(Derivative)]
 pub struct Edge<G>
 where

plexus/src/graph/face.rs

@@ -47,7 +47,7 @@ where
 }
 
 /// Face entity.
-#[derivative(Clone, Copy, Debug, Hash)]
+#[derivative(Debug, Hash)]
 #[derive(Derivative)]
 pub struct Face<G>
 where
@@ -638,16 +638,18 @@ where
             })
             .map(|arc| arc.key())
             .ok_or(GraphError::TopologyNotFound)?;
-        let geometry = self.data;
-        // TODO: Batch this operation by using the mutation API instead.
+        // TODO: `Clone` should not be needed here. Consolidate this using the
+        //       mutation API and move the necessary face data instead of
+        //       cloning it.
+        let data = self.get().clone();
         let arc: ArcView<_> = self.rebind(ab).expect_consistent();
         Ok(arc
             .remove()
             // Removing an edge between faces must yield a vertex.
             .expect_consistent()
             .into_outgoing_arc()
             .into_ring()
-            .get_or_insert_face_with(|| geometry))
+            .get_or_insert_face_with(|| data))
     }
 
     /// Connects faces with equal arity with faces inserted along their
@@ -753,11 +755,11 @@ where
         G: FaceCentroid,
         G::Vertex: AsPositionMut,
     {
-        let mut geometry = self.arc().source_vertex().data;
+        let mut data = self.arc().source_vertex().get().clone();
         let centroid = self.centroid();
         self.poke_with(move || {
-            *geometry.as_position_mut() = centroid;
-            geometry
+            *data.as_position_mut() = centroid;
+            data
         })
     }
 
@@ -803,11 +805,11 @@ where
         G::Vertex: AsPositionMut,
         VertexPosition<G>: EuclideanSpace,
     {
-        let mut geometry = self.arc().source_vertex().data;
+        let mut data = self.arc().source_vertex().get().clone();
         let position = self.centroid() + (self.normal()? * offset.into());
         Ok(self.poke_with(move || {
-            *geometry.as_position_mut() = position;
-            geometry
+            *data.as_position_mut() = position;
+            data
         }))
     }
 
@@ -840,15 +842,18 @@ where
         G::Vertex: AsPositionMut,
         VertexPosition<G>: EuclideanSpace,
     {
-        self.extrude_with(|geometry| geometry.map_position(|position| *position + translation))
+        self.extrude_with(|data| {
+            data.clone()
+                .map_position(|position| *position + translation)
+        })
     }
 
     /// Extrudes a face using the given vertex data.
     ///
     /// Returns the extruded face.
     pub fn extrude_with<F>(self, f: F) -> FaceView<&'a mut M>
     where
-        F: Fn(G::Vertex) -> G::Vertex,
+        F: Fn(&G::Vertex) -> G::Vertex,
     {
         // This should never fail here.
         let cache = FaceExtrudeCache::from_face(self.to_ref()).expect_consistent();