From 340fde213336ab85e76e7e2e863e5f291739cab1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20M=C3=BCller?= <stefan.mueller@aksdb.de>
Date: Wed, 13 May 2026 10:32:37 +0200
Subject: [PATCH] Add Graph::raw_incidences() iterator as a wrapper for
 step_incidence()

---
 src/models/graph.rs | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/models/graph.rs b/src/models/graph.rs
index c05567e..70372b3 100644
--- a/src/models/graph.rs
+++ b/src/models/graph.rs
@@ -98,8 +98,8 @@ impl Graph {
             vertex_header.first_incidence = next;
         } else {
             let graph: &Graph = self;
-            let mut incidence = self.vertices[source_vertex].first_incidence;
-            let (_, previous) = std::iter::from_fn(move || graph.step_incidence(&mut incidence))
+            let (_, previous) = self
+                .raw_incidences(source_vertex)
                 .find(|(_, f)| {
                     graph.incidences[*f]
                         .next
@@ -110,6 +110,11 @@ impl Graph {
         }
     }
 
+    fn raw_incidences(&self, v: Vertex) -> impl Iterator<Item = (VertexSlot, Edge)> {
+        let mut incidence = self.vertices[v].first_incidence;
+        std::iter::from_fn(move || self.step_incidence(&mut incidence))
+    }
+
     fn step_incidence(&self, incidence: &mut Option<IncidenceSlot>) -> Option<(VertexSlot, Edge)> {
         let current = (*incidence)?;
         let e = self.incidences.get_idx(current.0).unwrap();
@@ -171,8 +176,7 @@ impl GraphTopology for Graph {
     }
 
     fn adjacent_vertices(&self, v: Self::Vertex) -> impl Iterator<Item = Self::Vertex> {
-        let mut incidence = self.vertices[v].first_incidence;
-        std::iter::from_fn(move || self.step_incidence(&mut incidence))
+        self.raw_incidences(v)
             .map(|(vs, _)| self.vertices.get_idx(vs.0).unwrap())
     }
 
@@ -197,8 +201,7 @@ impl GraphTopology for Graph {
     }
 
     fn incidences(&self, v: Self::Vertex) -> impl Iterator<Item = (Self::Vertex, Self::Edge)> {
-        let mut incidence = self.vertices[v].first_incidence;
-        std::iter::from_fn(move || self.step_incidence(&mut incidence))
+        self.raw_incidences(v)
             .map(|(vs, e)| (self.vertices.get_idx(vs.0).unwrap(), self.normalize_edge(e)))
     }