Add GraphTopology trait and use it to interface graph model with algorithm

src/models.rs

@@ -1,6 +1,13 @@
-// TODO: Vertex value must not be public.
+use crate::traits::GraphTopology;
+
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
-pub struct Vertex(pub usize);
+pub struct Vertex(usize);
+
+impl From<Vertex> for usize {
+    fn from(v: Vertex) -> usize {
+        v.0
+    }
+}
 
 #[derive(Copy, Clone, PartialEq, Eq)]
 struct Incidence(usize);
@@ -14,8 +21,7 @@ struct IncidenceEntry {
     next: Option<Incidence>,
     neighbor: Vertex,
 }
-
-pub struct VertexNeighborIterator<'a> {
+struct VertexNeighborIterator<'a> {
     graph: &'a Graph,
     incidence: Option<Incidence>,
 }
@@ -50,37 +56,6 @@ impl Graph {
         }
     }
 
-    pub fn vertex_count(&self) -> usize {
-        self.vertices.len()
-    }
-
-    pub fn edge_count(&self) -> usize {
-        self.incidences.len() / 2
-    }
-
-    pub fn degree(&self, v: Vertex) -> usize {
-        self.vertices[v.0].incidence_count
-    }
-
-    pub fn are_adjacent(&self, v1: Vertex, v2: Vertex) -> bool {
-        self.neighbors(v1).find(|&x| x == v2).is_some()
-    }
-
-    // TODO: 'fn add_vertex()' needs variants for custom vertex data.
-    pub fn add_vertex(&mut self) -> Vertex {
-        self.vertices.push(VertexIncidenceHeader {
-            incidence_count: 0,
-            first_incidence: None,
-        });
-        Vertex(self.vertices.len() - 1)
-    }
-
-    // TODO: 'fn add_edge()' needs variants for custom edge data.
-    pub fn add_edge(&mut self, v1: Vertex, v2: Vertex) {
-        self.add_incidence(v1, v2);
-        self.add_incidence(v2, v1);
-    }
-
     fn add_incidence(&mut self, v1: Vertex, v2: Vertex) {
         self.incidences.push(IncidenceEntry {
             next: self.vertices[v1.0].first_incidence.take(),
@@ -89,17 +64,50 @@ impl Graph {
         self.vertices[v1.0].incidence_count += 1;
         self.vertices[v1.0].first_incidence = Some(Incidence(self.incidences.len() - 1));
     }
+}
 
-    pub fn vertices(&self) -> impl Iterator<Item = Vertex> {
+impl GraphTopology for Graph {
+    type Vertex = Vertex;
+
+    fn vertex_count(&self) -> usize {
+        self.vertices.len()
+    }
+
+    fn edge_count(&self) -> usize {
+        self.incidences.len() / 2
+    }
+
+    fn degree(&self, v: Self::Vertex) -> usize {
+        self.vertices[v.0].incidence_count
+    }
+
+    fn are_adjacent(&self, v1: Self::Vertex, v2: Self::Vertex) -> bool {
+        self.neighbors(v1).find(|&x| x == v2).is_some()
+    }
+
+    fn vertices(&self) -> impl Iterator<Item = Self::Vertex> {
         (0..self.vertices.len()).map(Vertex)
     }
 
-    pub fn neighbors(&self, v: Vertex) -> impl Iterator<Item = Vertex> {
+    fn neighbors(&self, v: Self::Vertex) -> impl Iterator<Item = Self::Vertex> {
         VertexNeighborIterator {
             graph: self,
             incidence: self.vertices[v.0].first_incidence,
         }
     }
+
+    fn add_vertex(&mut self) -> Self::Vertex {
+        self.vertices.push(VertexIncidenceHeader {
+            incidence_count: 0,
+            first_incidence: None,
+        });
+        Vertex(self.vertices.len() - 1)
+    }
+
+    fn add_edge(&mut self, v1: Self::Vertex, v2: Self::Vertex) {
+        self.add_incidence(v1, v2);
+        self.add_incidence(v2, v1);
+    }
 }
 
 #[cfg(test)]