This has been long standing TODO...
Note that remaining usages of BKE_xxx_delete should all be carefully
checked for and utilmately nuked in favor of `BKE_id_delete()`, think we
still have quiet a few bugs hidden in those (code seems to usually
assume those functions do a full ID deletion, which is not the case).
Only covers direct usages of new callbacks from IDTypeInfo.
We still have a lot of those switch/case, many can probably go away
with minimal refactor now, but that will be for later.
This was particularly strange because we had a _free_data() function.
But still the one I replaced was of course the _free() one.
And we should rename the _free_data_ function later to avoid confusions.
Introduce new IDTypeInfo structure.
Each ID type will have its own, with some minimal basic common info,
and ID management callbacks.
This patch only does it for Object type, for demo/testing purpose.
Moving all existing IDs is a goal of next "cleanup Friday".
Note that BKE_idcode features should then be merged back into BKE_idtype -
but this will have to be done later, once all ID types have been properly
converted to the new system.
Another later TODO might be to try and add callbacks for file read/write,
and lib_query ID usages looper.
This is part of T73719.
Thanks to @brecht for initial idea, and reviewing the patch.
Differential Revision: https://developer.blender.org/D6966
Even though we do not have much of those, this might change in the
future, and in any case having specific functions for this ID type in
generic `BKE_lib` area was really confusing.
Having functions defined in `BKE_lib_id.h` implemented into
`lib_remap.c` was confusing at best.
Besides trivial code splitting and header includes cleanup, had to add a
new `lib_intern.h` header for callbacks used by both remapping and
deletion code.
