Implement C++ methods for DNA structures

This change makes it possible to add implementation of common
C++ methods for DNA structures which helps ensuring unsafe
operations like shallow copy are done explicitly.

For example, creating a shallow copy used to be:

  Object temp_object = *input_object;

In the C++ context it was seen like the temp_object is
properly decoupled from the input object, while in the
reality is it not. Now this code becomes:

  Object temp_object = blender::dna::shallow_copy(*input_object);

The copy and move constructor and assignment operators are
now explicitly disabled.

Other than a more explicit resource management this change
also solves a lot of warnings generated by the implicitly
defined copy constructors w.r.t dealing with deprecated fields.
These warnings were generated by Apple Clang when a shallow
object copy was created via implicitly defined copy constructor.

In order to enable C++ methods for DNA structures a newly added
macro `DNA_DEFINE_CXX_METHODS()` is to be used:

  tpyedef struct Object {
    DNA_DEFINE_CXX_METHODS(Object)
    ...
  } Object;

For the shallow copy use `blender::dna::shallow_copy()`.

The implementation of the memcpy is hidden via an internal DNA
function to avoid pulling `string.h` into every DNA header.
This means that the solution does not affect on the headers
dependencies.

---

Ideally `DNA_shallow_copy` would be defined in a more explicit
header, but don;t think we have a suitable one already. Maybe
we can introduce `DNA_access.h` ?

Differential Revision: https://developer.blender.org/D14427

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/depsgraph/intern/depsgraph_query_iter.cc b/source/blender/depsgraph/intern/depsgraph_query_iter.cc
index 5788e8efa07..d5566e4be98 100644
--- a/source/blender/depsgraph/intern/depsgraph_query_iter.cc
+++ b/source/blender/depsgraph/intern/depsgraph_query_iter.cc
@@ -167,7 +167,7 @@ bool deg_iterator_duplis_step(DEGObjectIterData *data)
     /* Temporary object to evaluate. */
     Object *dupli_parent = data->dupli_parent;
     Object *temp_dupli_object = &data->temp_dupli_object;
-    *temp_dupli_object = *dob->ob;
+    *temp_dupli_object = blender::dna::shallow_copy(*dob->ob);
     temp_dupli_object->base_flag = dupli_parent->base_flag | BASE_FROM_DUPLI;
     temp_dupli_object->base_local_view_bits = dupli_parent->base_local_view_bits;
     temp_dupli_object->runtime.local_collections_bits =