Sergey Sharybin
03df72ee4e
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