Cleanup: Refactor spline copying functions

Make the virtual functions protected and simpler, so that the logic is
better contained in the base class's implementation. Also introduce a
`copy_without_attributes` method to be used for realizing instances.

1 files changed, 54 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/spline_base.cc b/source/blender/blenkernel/intern/spline_base.cc
index c18f44e07b2..aa0d95d4d61 100644
--- a/source/blender/blenkernel/intern/spline_base.cc
+++ b/source/blender/blenkernel/intern/spline_base.cc
@@ -40,6 +40,60 @@ Spline::Type Spline::type() const
   return type_;
 }
 
+void Spline::copy_base_settings(const Spline &src, Spline &dst)
+{
+  dst.normal_mode = src.normal_mode;
+  dst.is_cyclic_ = src.is_cyclic_;
+}
+
+static SplinePtr create_spline(const Spline::Type type)
+{
+  switch (type) {
+    case Spline::Type::Poly:
+      return std::make_unique<PolySpline>();
+    case Spline::Type::Bezier:
+      return std::make_unique<BezierSpline>();
+    case Spline::Type::NURBS:
+      return std::make_unique<NURBSpline>();
+  }
+  BLI_assert_unreachable();
+  return {};
+}
+
+/**
+ * Return a new spline with the same data, settings, and attributes.
+ */
+SplinePtr Spline::copy() const
+{
+  SplinePtr dst = this->copy_without_attributes();
+  dst->attributes = this->attributes;
+  return dst;
+}
+
+/**
+ * Return a new spline with the same type and settings like "cyclic", but without any data.
+ */
+SplinePtr Spline::copy_only_settings() const
+{
+  SplinePtr dst = create_spline(type_);
+  this->copy_base_settings(*this, *dst);
+  this->copy_settings(*dst);
+  return dst;
+}
+
+/**
+ * The same as #copy, but skips copying dynamic attributes to the new spline.
+ */
+SplinePtr Spline::copy_without_attributes() const
+{
+  SplinePtr dst = this->copy_only_settings();
+  this->copy_data(*dst);
+
+  /* Though the attributes storage is empty, it still needs to know the correct size. */
+  dst->attributes.reallocate(dst->size());
+  return dst;
+}
+
 void Spline::translate(const blender::float3 &translation)
 {
   for (float3 &position : this->positions()) {