Use an edm4hep::TrackerHit inside the SourceLink instead of a dedicated type

k4ActsTracking/include/k4ActsTracking/Measurement.hxx

@@ -24,6 +24,8 @@
 #include "Acts/EventData/detail/ParameterTraits.hpp"
 #include "Acts/EventData/detail/PrintParameters.hpp"
 
+#include <boost/container/static_vector.hpp>
+
 #include <array>
 #include <variant>
 

k4ActsTracking/include/k4ActsTracking/SeedSpacePoint.hxx

@@ -18,8 +18,11 @@
  */
 #pragma once
 
+#include "k4ActsTracking/SourceLink.hxx"
+
 #include <Acts/Definitions/Algebra.hpp>
 #include <Acts/Definitions/Common.hpp>
+
 #include <cmath>
 #include <vector>
 
@@ -58,9 +61,9 @@ namespace ACTSTracking {
     constexpr float varianceR() const { return m_varianceRho; }
     constexpr float varianceZ() const { return m_varianceZ; }
 
-    constexpr SourceLink sourceLink() const { return m_sourceLink; }
+    const SourceLink& sourceLink() const { return m_sourceLink; }
 
-    const std::optional<float> t() const { return m_sourceLink.edm4hepTHitP()->getTime(); }
+    std::optional<float> t() const { return m_sourceLink.edm4hepHit().getTime(); }
     /// @TODO missing: const std::optional<float> varianceT() const
 
   private:
@@ -85,7 +88,7 @@ namespace ACTSTracking {
  * that the same measurement index always produces the same space point?
  * no need to check r since it is fully defined by x/y
  */
-  constexpr bool operator==(const SeedSpacePoint& lhs, const SeedSpacePoint& rhs) {
+  inline bool operator==(const SeedSpacePoint& lhs, const SeedSpacePoint& rhs) {
     return (lhs.sourceLink() == rhs.sourceLink()) and (lhs.x() == rhs.x()) and (lhs.y() == rhs.y()) and
            (lhs.z() == rhs.z()) and (lhs.varianceR() == rhs.varianceR()) and (lhs.varianceZ() == rhs.varianceZ());
   }

k4ActsTracking/include/k4ActsTracking/SourceLink.hxx

@@ -18,8 +18,9 @@
  */
 #pragma once
 
-#include <edm4hep/TrackerHitPlane.h>
+#include <edm4hep/TrackerHit.h>
 
+#include "Acts/EventData/SourceLink.hpp"
 #include "Acts/Surfaces/Surface.hpp"
 
 #include "k4ActsTracking/GeometryContainers.hxx"
@@ -29,7 +30,7 @@ namespace ACTSTracking {
   class SourceLink final {
   public:
     //! \brief Construct from geometry identifier and hit
-    SourceLink(Acts::GeometryIdentifier gid, std::size_t index, edm4hep::TrackerHitPlane* edmhit)
+    SourceLink(Acts::GeometryIdentifier gid, std::size_t index, const edm4hep::TrackerHit edmhit)
         : m_geometryId(gid), m_index(index), m_edm4hephit(edmhit) {}
 
     // Construct an invalid source link. Must be default constructible to
@@ -46,12 +47,12 @@ namespace ACTSTracking {
     constexpr std::size_t index() const { return m_index; }
     /// Access the edm4hep TrackerHitPlane
     /// @TODO: We want this to be a TrackerHit to support multiple types of tracking detector. However, TrackerHitPlane is currently not derived from TrackerHit as expected.
-    constexpr edm4hep::TrackerHitPlane* edm4hepTHitP() const { return m_edm4hephit; }
+    edm4hep::TrackerHit edm4hepHit() const { return m_edm4hephit; }
 
   private:
-    Acts::GeometryIdentifier  m_geometryId;
-    std::size_t               m_index      = -1;
-    edm4hep::TrackerHitPlane* m_edm4hephit = nullptr;
+    Acts::GeometryIdentifier m_geometryId;
+    std::size_t              m_index = -1;
+    edm4hep::TrackerHit      m_edm4hephit{edm4hep::TrackerHit::makeEmpty()};
 
     friend constexpr bool operator==(const SourceLink& lhs, const SourceLink& rhs) {
       return (lhs.m_geometryId == rhs.m_geometryId) and (lhs.m_index == rhs.m_index) and

k4ActsTracking/src/components/ACTSSeededCKFTrackingAlg.cxx

@@ -172,7 +172,7 @@ std::tuple<edm4hep::TrackCollection, edm4hep::TrackCollection> ACTSSeededCKFTrac
     localCov(0, 0)                          = std::pow(hitplane.getDu() * Acts::UnitConstants::mm, 2);
     localCov(1, 1)                          = std::pow(hitplane.getDv() * Acts::UnitConstants::mm, 2);
 
-    ACTSTracking::SourceLink  sourceLink(surface->geometryId(), measurements.size(), &hitPair.second);
+    ACTSTracking::SourceLink  sourceLink(surface->geometryId(), measurements.size(), hitPair.second);
     Acts::SourceLink          src_wrap{sourceLink};
     ACTSTracking::Measurement meas =
         ACTSTracking::makeMeasurement(src_wrap, loc, localCov, Acts::eBoundLoc0, Acts::eBoundLoc1);
@@ -467,7 +467,7 @@ std::tuple<edm4hep::TrackCollection, edm4hep::TrackCollection> ACTSSeededCKFTrac
       // hits
       for (const ACTSTracking::SeedSpacePoint* sp : seed.sp()) {
         const ACTSTracking::SourceLink& sl = sp->sourceLink();
-        seedTrack.addToTrackerHits(*(sl.edm4hepTHitP()));  //trackHit);
+        seedTrack.addToTrackerHits(sl.edm4hepHit());
       }
 
       seedTrack.addToTrackStates(*seedTrackState);

k4ActsTracking/src/components/Helpers.cxx

@@ -98,7 +98,7 @@ namespace ACTSTracking {
 
       auto sl = trk_state.getUncalibratedSourceLink().get<ACTSTracking::SourceLink>();
 
-      edm4hep::TrackerHit curr_hit(*sl.edm4hepTHitP());
+      const auto curr_hit = sl.edm4hepHit();
 
       hitsOnTrack.push_back(curr_hit);