refactor(DrawingException): factor out extraction of ghost+obstacle

src/drawing/drawing.rs

@@ -66,6 +66,17 @@ impl fmt::Debug for DrawingException {
     }
 }
 
+impl DrawingException {
+    pub fn maybe_ghost_and_obstacle(&self) -> Option<(&PrimitiveShape, PrimitiveIndex)> {
+        match self {
+            Self::NoTangents(_) => None,
+            Self::Infringement(Infringement(ghost, obstacle)) => Some((ghost, *obstacle)),
+            Self::Collision(Collision(ghost, obstacle)) => Some((ghost, *obstacle)),
+            Self::AlreadyConnected(_) => None,
+        }
+    }
+}
+
 // TODO add real error messages + these should eventually use Display
 #[derive(Error, Debug, Clone, Copy)]
 #[error("{0:?} infringes on {1:?}")]

src/router/router.rs

@@ -15,7 +15,7 @@ use crate::{
         head::GetFace,
         primitive::MakePrimitiveShape,
         rules::AccessRules,
-        Collision, DrawingException, Guide, Infringement,
+        Guide,
     },
     geometry::{
         primitive::PrimitiveShape,
@@ -116,18 +116,8 @@ impl<R: AccessRules> AstarStrategy<Navmesh, f64, BandTermsegIndex> for RouterAst
                         DrawException::CannotWrapAround(.., layout_err) => layout_err,
                     };
 
-                    let (ghost, obstacle) = match layout_err {
+                    let (ghost, obstacle) = layout_err.maybe_ghost_and_obstacle()?;
-                        DrawingException::NoTangents(..) => return None,
+                    self.probe_ghosts = vec![*ghost];
-                        DrawingException::Infringement(Infringement(ghost, obstacle)) => {
-                            (ghost, obstacle)
-                        }
-                        DrawingException::Collision(Collision(ghost, obstacle)) => {
-                            (ghost, obstacle)
-                        }
-                        DrawingException::AlreadyConnected(..) => return None,
-                    };
-
-                    self.probe_ghosts = vec![ghost];
                     self.probe_obstacles = vec![obstacle];
                 }
                 None