feat(geo): TrackingVolume gets surface storage

Core/include/Acts/Geometry/TrackingVolume.hpp

@@ -322,6 +322,25 @@ class TrackingVolume : public Volume {
   /// @param portal The portal to add
   void addPortal(std::shared_ptr<Portal> portal);
 
+  using MutableSurfaceRange =
+      detail::TransformRange<detail::Dereference,
+                             std::vector<std::shared_ptr<Surface>>>;
+  using SurfaceRange =
+      detail::TransformRange<detail::ConstDereference,
+                             const std::vector<std::shared_ptr<Surface>>>;
+
+  /// Return all surfaces registered under this tracking volume
+  /// @return the range of surfaces
+  SurfaceRange surfaces() const;
+
+  /// Return mutable view of the registered surfaces under this tracking volume
+  /// @return the range of surfaces
+  MutableSurfaceRange surfaces();
+
+  /// Add a surface to this tracking volume
+  /// @param surface The surface to add
+  void addSurface(std::shared_ptr<Surface> surface);
+
   /// Add a child volume to this tracking volume
   /// @param volume The volume to add
   /// @note The @p volume will have its mother volume assigned to @p this.
@@ -516,6 +535,7 @@ class TrackingVolume : public Volume {
 
   std::vector<std::unique_ptr<TrackingVolume>> m_volumes;
   std::vector<std::shared_ptr<Portal>> m_portals;
+  std::vector<std::shared_ptr<Surface>> m_surfaces;
 };
 
 }  // namespace Acts

Core/src/Geometry/TrackingVolume.cpp

@@ -663,7 +663,25 @@ TrackingVolume::MutablePortalRange TrackingVolume::portals() {
 }
 
 void TrackingVolume::addPortal(std::shared_ptr<Portal> portal) {
+  if (portal == nullptr) {
+    throw std::invalid_argument("Portal is nullptr");
+  }
   m_portals.push_back(std::move(portal));
 }
 
+TrackingVolume::SurfaceRange TrackingVolume::surfaces() const {
+  return SurfaceRange{m_surfaces};
+}
+
+TrackingVolume::MutableSurfaceRange TrackingVolume::surfaces() {
+  return MutableSurfaceRange{m_surfaces};
+}
+
+void TrackingVolume::addSurface(std::shared_ptr<Surface> surface) {
+  if (surface == nullptr) {
+    throw std::invalid_argument("Surface is nullptr");
+  }
+  m_surfaces.push_back(std::move(surface));
+}
+
 }  // namespace Acts