autorouter: make it possible to delegate the loop outside `.autoroute()`

src/autorouter/autorouter.rs

@@ -1,7 +1,10 @@
 use std::sync::{Arc, Mutex};
 
 use geo::Point;
-use petgraph::visit::{EdgeRef, IntoEdgeReferences};
+use petgraph::{
+    graph::EdgeIndices,
+    visit::{EdgeRef, IntoEdgeReferences},
+};
 use spade::InsertionError;
 
 use crate::{
@@ -12,6 +15,57 @@ use crate::{
     triangulation::GetVertexIndex,
 };
 
+pub struct Autoroute {
+    edge_indices: EdgeIndices<usize>,
+}
+
+impl Autoroute {
+    pub fn next<R: RulesTrait>(
+        &mut self,
+        autorouter: &mut Autorouter<R>,
+        observer: &mut impl RouterObserverTrait<R>,
+    ) -> Option<()> {
+        let Some(ratline) = self.edge_indices.next() else {
+            return None;
+        };
+        let (from, to) = autorouter.ratsnest.graph().edge_endpoints(ratline).unwrap();
+
+        let (from_dot, to_dot) = {
+            let layout = autorouter.router.layout();
+            let mut layout = layout.lock().unwrap();
+
+            let from_dot = match autorouter
+                .ratsnest
+                .graph()
+                .node_weight(from)
+                .unwrap()
+                .vertex_index()
+            {
+                RatsnestVertexIndex::FixedDot(dot) => dot,
+                RatsnestVertexIndex::Zone(zone) => layout.zone_apex(zone),
+            };
+
+            let to_dot = match autorouter
+                .ratsnest
+                .graph()
+                .node_weight(to)
+                .unwrap()
+                .vertex_index()
+            {
+                RatsnestVertexIndex::FixedDot(dot) => dot,
+                RatsnestVertexIndex::Zone(zone) => layout.zone_apex(zone),
+            };
+
+            (from_dot, to_dot)
+        };
+
+        autorouter
+            .router
+            .route_band(from_dot, to_dot, 100.0, observer);
+        Some(())
+    }
+}
+
 pub struct Autorouter<R: RulesTrait> {
     ratsnest: Ratsnest,
     router: Router<R>,
@@ -27,38 +81,15 @@ impl<R: RulesTrait> Autorouter<R> {
     }
 
     pub fn autoroute(&mut self, observer: &mut impl RouterObserverTrait<R>) {
-        for ratline in self.ratsnest.graph().edge_references() {
-            let from = self
-                .ratsnest
-                .graph()
-                .node_weight(ratline.source())
-                .unwrap()
-                .vertex_index();
-            let to = self
-                .ratsnest
-                .graph()
-                .node_weight(ratline.target())
-                .unwrap()
-                .vertex_index();
+        let mut it = self.autoroute_iter();
+        while let Some(()) = it.next(self, observer) {
+            //
+        }
+    }
 
-            let (from_dot, to_dot) = {
-                let layout = self.router.layout();
-                let mut layout = layout.lock().unwrap();
-
-                let from_dot = match from {
-                    RatsnestVertexIndex::FixedDot(dot) => dot,
-                    RatsnestVertexIndex::Zone(zone) => layout.zone_apex(zone),
-                };
-
-                let to_dot = match to {
-                    RatsnestVertexIndex::FixedDot(dot) => dot,
-                    RatsnestVertexIndex::Zone(zone) => layout.zone_apex(zone),
-                };
-
-                (from_dot, to_dot)
-            };
-
-            self.router.route_band(from_dot, to_dot, 100.0, observer);
+    pub fn autoroute_iter(&mut self) -> Autoroute {
+        Autoroute {
+            edge_indices: self.ratsnest.graph().edge_indices(),
         }
     }
 

src/autorouter/ratsnest.rs

@@ -4,9 +4,9 @@ use enum_dispatch::enum_dispatch;
 use geo::Point;
 use petgraph::{
     data::{Element, FromElements},
-    stable_graph::{NodeIndex, StableGraph, StableUnGraph},
+    graph::{NodeIndex, UnGraph},
     unionfind::UnionFind,
-    visit::{self, EdgeRef, IntoEdgeReferences, NodeIndexable},
+    visit::{EdgeRef, IntoEdgeReferences, NodeIndexable},
 };
 use spade::{HasPosition, InsertionError, Point2};
 
@@ -53,7 +53,7 @@ impl HasPosition for VertexWeight {
 }
 
 pub struct Ratsnest {
-    graph: StableUnGraph<VertexWeight, TriangulationEdgeWeight, usize>,
+    graph: UnGraph<VertexWeight, TriangulationEdgeWeight, usize>,
 }
 
 impl Ratsnest {
@@ -65,7 +65,7 @@ impl Ratsnest {
         }
 
         let mut this = Self {
-            graph: StableUnGraph::default(),
+            graph: UnGraph::default(),
         };
 
         let mut triangulations = HashMap::new();
@@ -149,7 +149,7 @@ impl Ratsnest {
         Ok(this)
     }
 
-    pub fn graph(&self) -> &StableUnGraph<VertexWeight, TriangulationEdgeWeight, usize> {
+    pub fn graph(&self) -> &UnGraph<VertexWeight, TriangulationEdgeWeight, usize> {
         &self.graph
     }
 }