refactor(autorouter/ratsnest): Move unionfind to new file, don't use `.graph()` there

committed.toml

@@ -21,6 +21,7 @@ allowed_scopes = [
   "autorouter/autoroute",
   "autorouter/autorouter",
   "autorouter/compare_detours",
+  "autorouter/conncomps",
   "autorouter/execution",
   "autorouter/history",
   "autorouter/invoker",

src/autorouter/conncomps.rs

@@ -0,0 +1,52 @@
+// SPDX-FileCopyrightText: 2025 Topola contributors
+//
+// SPDX-License-Identifier: MIT
+
+use derive_getters::Getters;
+use petgraph::unionfind::UnionFind;
+use specctra_core::rules::AccessRules;
+
+use crate::{
+    drawing::{graph::PrimitiveIndex, primitive::GetJoints},
+    graph::GetIndex,
+    layout::Layout,
+};
+
+#[derive(Clone, Getters)]
+pub struct Conncomps {
+    unionfind: UnionFind<usize>,
+}
+
+impl Conncomps {
+    pub fn new(layout: &Layout<impl AccessRules>) -> Self {
+        let mut unionfind = UnionFind::new(layout.drawing().geometry().dot_index_bound());
+
+        for primitive in layout.drawing().primitive_nodes() {
+            match primitive {
+                PrimitiveIndex::FixedSeg(seg) => {
+                    let joints = layout.drawing().primitive(seg).joints();
+                    unionfind.union(joints.0.index(), joints.1.index());
+                }
+                PrimitiveIndex::LoneLooseSeg(seg) => {
+                    let joints = layout.drawing().primitive(seg).joints();
+                    unionfind.union(joints.0.index(), joints.1.index());
+                }
+                PrimitiveIndex::SeqLooseSeg(seg) => {
+                    let joints = layout.drawing().primitive(seg).joints();
+                    unionfind.union(joints.0.index(), joints.1.index());
+                }
+                PrimitiveIndex::FixedBend(bend) => {
+                    let joints = layout.drawing().primitive(bend).joints();
+                    unionfind.union(joints.0.index(), joints.1.index());
+                }
+                PrimitiveIndex::LooseBend(bend) => {
+                    let joints = layout.drawing().primitive(bend).joints();
+                    unionfind.union(joints.0.index(), joints.1.index());
+                }
+                _ => (),
+            }
+        }
+
+        Self { unionfind }
+    }
+}

src/autorouter/mod.rs

@@ -5,6 +5,7 @@
 pub mod autoroute;
 mod autorouter;
 pub mod compare_detours;
+pub mod conncomps;
 pub mod execution;
 pub mod history;
 pub mod invoker;

src/autorouter/ratsnest.rs

@@ -6,15 +6,11 @@ use std::collections::BTreeMap;
 
 use enum_dispatch::enum_dispatch;
 use geo::Point;
-use petgraph::{
-    data::Element,
-    prelude::StableUnGraph,
-    unionfind::UnionFind,
-    visit::{EdgeRef, IntoEdgeReferences, NodeIndexable},
-};
+use petgraph::{data::Element, prelude::StableUnGraph, visit::NodeIndexable};
 use spade::{HasPosition, InsertionError, Point2};
 
 use crate::{
+    autorouter::conncomps::Conncomps,
     drawing::{
         band::BandTermsegIndex,
         dot::FixedDotIndex,
@@ -74,11 +70,7 @@ pub struct Ratsnest {
 
 impl Ratsnest {
     pub fn new(layout: &Layout<impl AccessRules>) -> Result<Self, InsertionError> {
-        let mut unionfind = UnionFind::new(layout.drawing().geometry().graph().node_bound());
-
-        for edge in layout.drawing().geometry().graph().edge_references() {
-            unionfind.union(edge.source().index(), edge.target().index());
-        }
+        let conncomps = Conncomps::new(layout);
 
         let mut this = Self {
             graph: StableUnGraph::default(),
@@ -145,7 +137,7 @@ impl Ratsnest {
             if let Some((source, target)) = g.edge_endpoints(i) {
                 let source_index = g.node_weight(source).unwrap().node_index().index();
                 let target_index = g.node_weight(target).unwrap().node_index().index();
-                !unionfind.equiv(source_index, target_index)
+                !conncomps.unionfind().equiv(source_index, target_index)
             } else {
                 true
             }

src/geometry/geometry.rs

@@ -7,7 +7,7 @@ use enum_dispatch::enum_dispatch;
 use geo::Point;
 use petgraph::{
     stable_graph::StableDiGraph,
-    visit::{EdgeRef, Walker},
+    visit::{EdgeRef, NodeIndexable, Walker},
     Direction::{Incoming, Outgoing},
 };
 use serde::{Deserialize, Serialize};
@@ -518,6 +518,18 @@ impl<
     pub fn bend_joints(&self, bend: BI) -> (DI, DI) {
         self.joints(bend.into())
     }
+
+    pub fn dot_index_bound(&self) -> usize {
+        self.graph.node_bound()
+    }
+
+    pub fn seg_index_bound(&self) -> usize {
+        self.graph.node_bound()
+    }
+
+    pub fn bend_index_bound(&self) -> usize {
+        self.graph.node_bound()
+    }
 }
 
 impl<PW: Copy + Retag<Index = PI>, DW, SW, BW, CW, Cel, PI, DI, SI, BI>

tests/common/mod.rs

@@ -4,9 +4,9 @@
 
 use std::{fs::File, io::BufReader};
 
-use petgraph::{unionfind::UnionFind, visit::NodeIndexable};
 use topola::{
     autorouter::{
+        conncomps::Conncomps,
         history::{History, HistoryError},
         invoker::{Invoker, InvokerError},
         Autorouter,
@@ -160,7 +160,7 @@ pub fn assert_single_layer_groundless_autoroute(
     autorouter: &mut Autorouter<impl AccessMesadata>,
     layername: &str,
 ) {
-    let unionfind = unionfind(autorouter);
+    let conncomps = Conncomps::new(autorouter.board().layout());
 
     for ratline in autorouter.ratsnest().graph().edge_indices() {
         let (origin_dot, destination_dot) = ratline.ref_(autorouter).endpoint_dots();
@@ -217,8 +217,8 @@ pub fn assert_single_layer_groundless_autoroute(
 
         if let Some(netname) = autorouter.board().layout().rules().net_netname(net) {
             // We don't route ground.
-            let org = unionfind.find(origin_dot.index());
-            let desc = unionfind.find(destination_dot.index());
+            let org = conncomps.unionfind().find(origin_dot.index());
+            let desc = conncomps.unionfind().find(destination_dot.index());
 
             if netname != "GND" {
                 assert_eq!(org, desc);
@@ -256,35 +256,3 @@ pub fn assert_band_length(
         rel_err
     );
 }
-
-fn unionfind(autorouter: &mut Autorouter<impl AccessMesadata>) -> UnionFind<usize> {
-    for ratline in autorouter.ratsnest().graph().edge_indices() {
-        // Accessing endpoints may create new dots because apex construction is lazy, so we access
-        // tem all before starting unionfind, as it requires a constant index bound.
-        let _ = ratline.ref_(autorouter).endpoint_dots();
-    }
-
-    let mut unionfind = UnionFind::new(
-        autorouter
-            .board()
-            .layout()
-            .drawing()
-            .geometry()
-            .graph()
-            .node_bound(),
-    );
-
-    for primitive in autorouter.board().layout().drawing().primitive_nodes() {
-        for joined in autorouter
-            .board()
-            .layout()
-            .drawing()
-            .geometry()
-            .joineds(primitive)
-        {
-            unionfind.union(primitive.index(), joined.index());
-        }
-    }
-
-    unionfind
-}