From 2fdb8aee6c36e6ad4ba83cee2861a7152f418aee Mon Sep 17 00:00:00 2001
From: Alain Emilia Anna Zscheile <fogti+devel@ytrizja.de>
Date: Sat, 5 Oct 2024 00:02:26 +0200
Subject: [PATCH] feat(stepper,autorouter): get rid of Step::finish

---
 src/autorouter/compare_detours.rs | 44 +++++++------------------------
 src/autorouter/execution.rs       | 16 +++++------
 src/autorouter/invoker.rs         |  2 +-
 src/stepper.rs                    | 11 --------
 4 files changed, 19 insertions(+), 54 deletions(-)

diff --git a/src/autorouter/compare_detours.rs b/src/autorouter/compare_detours.rs
index 9b705b0..f4c6479 100644
--- a/src/autorouter/compare_detours.rs
+++ b/src/autorouter/compare_detours.rs
@@ -3,6 +3,7 @@
 //! while providing access to navigation meshes, traces, ghost shapes, and
 //! obstacles encountered.
 
+use core::task::Poll;
 use petgraph::graph::EdgeIndex;
 
 use crate::{
@@ -11,7 +12,7 @@ use crate::{
     geometry::{primitive::PrimitiveShape, shape::MeasureLength},
     graph::MakeRef,
     router::{navmesh::Navmesh, trace::TraceStepper},
-    stepper::{Step, StepError},
+    stepper::{PollStep, Step, StepError},
 };
 
 use super::{
@@ -20,23 +21,6 @@ use super::{
     Autorouter, AutorouterError, AutorouterOptions,
 };
 
-pub enum CompareDetoursStatus {
-    Running,
-    Finished(f64, f64),
-}
-
-impl TryInto<(f64, f64)> for CompareDetoursStatus {
-    type Error = ();
-    fn try_into(self) -> Result<(f64, f64), ()> {
-        match self {
-            CompareDetoursStatus::Running => Err(()),
-            CompareDetoursStatus::Finished(total_length1, total_length2) => {
-                Ok((total_length1, total_length2))
-            }
-        }
-    }
-}
-
 pub struct CompareDetoursExecutionStepper {
     autoroute: AutorouteExecutionStepper,
     next_autoroute: Option<AutorouteExecutionStepper>,
@@ -72,22 +56,17 @@ impl StepError for CompareDetoursExecutionStepper {
 
 // XXX: Do we really need this to be a stepper? We don't use at the moment, as sorting functions
 // aren't steppable either. It may be useful for debugging later on tho.
-impl<M: AccessMesadata> Step<Autorouter<M>, CompareDetoursStatus>
-    for CompareDetoursExecutionStepper
-{
-    fn step(
+impl<M: AccessMesadata> PollStep<Autorouter<M>, (f64, f64)> for CompareDetoursExecutionStepper {
+    fn poll_step(
         &mut self,
         autorouter: &mut Autorouter<M>,
-    ) -> Result<CompareDetoursStatus, AutorouterError> {
+    ) -> Poll<Result<(f64, f64), AutorouterError>> {
         if self.done {
-            return Ok(CompareDetoursStatus::Finished(
-                self.total_length1,
-                self.total_length2,
-            ));
+            return Poll::Ready(Ok((self.total_length1, self.total_length2)));
         }
 
         match self.autoroute.step(autorouter)? {
-            AutorouteStatus::Running => Ok(CompareDetoursStatus::Running),
+            AutorouteStatus::Running => Poll::Pending,
             AutorouteStatus::Routed(band_termseg) => {
                 let length = band_termseg
                     .ref_(autorouter.board.layout().drawing())
@@ -99,22 +78,19 @@ impl<M: AccessMesadata> Step<Autorouter<M>, CompareDetoursStatus>
                     self.total_length2 += length;
                 }
 
-                Ok(CompareDetoursStatus::Running)
+                Poll::Pending
             }
             AutorouteStatus::Finished => {
                 if let Some(next_autoroute) = self.next_autoroute.take() {
                     autorouter.undo_autoroute_ratlines(vec![self.ratline1, self.ratline2])?;
                     self.autoroute = next_autoroute;
 
-                    Ok(CompareDetoursStatus::Running)
+                    Poll::Pending
                 } else {
                     self.done = true;
                     autorouter.undo_autoroute_ratlines(vec![self.ratline2, self.ratline1])?;
 
-                    Ok(CompareDetoursStatus::Finished(
-                        self.total_length1,
-                        self.total_length2,
-                    ))
+                    Poll::Ready(Ok((self.total_length1, self.total_length2)))
                 }
             }
         }
diff --git a/src/autorouter/execution.rs b/src/autorouter/execution.rs
index 1e533a8..f5b6fe5 100644
--- a/src/autorouter/execution.rs
+++ b/src/autorouter/execution.rs
@@ -10,7 +10,7 @@ use crate::{
 
 use super::{
     autoroute::{AutorouteExecutionStepper, AutorouteStatus},
-    compare_detours::{CompareDetoursExecutionStepper, CompareDetoursStatus},
+    compare_detours::CompareDetoursExecutionStepper,
     invoker::{Invoker, InvokerError},
     measure_length::MeasureLengthExecutionStepper,
     place_via::PlaceViaExecutionStepper,
@@ -59,15 +59,15 @@ impl ExecutionStepper {
                 Poll::Ready("finished removing bands".to_string())
             }
             ExecutionStepper::CompareDetours(compare_detours) => {
-                match compare_detours.step(autorouter)? {
-                    CompareDetoursStatus::Running => Poll::Pending,
-                    CompareDetoursStatus::Finished(total_length1, total_length2) => {
-                        Poll::Ready(format!(
+                return compare_detours.poll_step(autorouter).map(|res| {
+                    res.map(|(total_length1, total_length2)| {
+                        format!(
                             "total detour lengths are {} and {}",
                             total_length1, total_length2
-                        ))
-                    }
-                }
+                        )
+                    })
+                    .map_err(Into::into)
+                });
             }
             ExecutionStepper::MeasureLength(measure_length) => {
                 let length = measure_length.doit(autorouter)?;
diff --git a/src/autorouter/invoker.rs b/src/autorouter/invoker.rs
index 74aaa74..0f70a77 100644
--- a/src/autorouter/invoker.rs
+++ b/src/autorouter/invoker.rs
@@ -10,7 +10,7 @@ use crate::{
     drawing::graph::PrimitiveIndex,
     geometry::primitive::PrimitiveShape,
     router::{navmesh::Navmesh, trace::TraceStepper},
-    stepper::{PollStep, Step},
+    stepper::PollStep,
 };
 
 use super::{
diff --git a/src/stepper.rs b/src/stepper.rs
index 0c4909a..5e15753 100644
--- a/src/stepper.rs
+++ b/src/stepper.rs
@@ -6,17 +6,6 @@ pub trait StepError {
 
 pub trait Step<C, S>: StepError {
     fn step(&mut self, context: &mut C) -> Result<S, Self::Error>;
-
-    fn finish<O>(&mut self, context: &mut C) -> Result<O, Self::Error>
-    where
-        S: TryInto<O>,
-    {
-        loop {
-            if let Ok(outcome) = self.step(context)?.try_into() {
-                return Ok(outcome);
-            }
-        }
-    }
 }
 
 // Note that PollStep's `S` is usually not the same as Step's `S`.