Python API: Add functions to ensure and clear IDProperties

This adds id_properties_clear() and id_properties_ensure() functions
to RNA structs. This is meant as an initial change based on discussion
in review of D9697. However, they may be useful in other situations.

The change requires refactoring the internal idproperties callback to
return a pointer to the IDProperty pointer, which actually turns out
to be quite a nice cleanup.

An id_properties attribute could be added in the future potentially.

Differential Revision: https://developer.blender.org/D11908

1 files changed, 7 insertions, 6 deletions

diff --git a/source/blender/makesrna/intern/rna_ID.c b/source/blender/makesrna/intern/rna_ID.c
index 694636f0c94..38b00afdc8f 100644
--- a/source/blender/makesrna/intern/rna_ID.c
+++ b/source/blender/makesrna/intern/rna_ID.c
@@ -493,9 +493,10 @@ StructRNA *rna_ID_refine(PointerRNA *ptr)
   return ID_code_to_RNA_type(GS(id->name));
 }
 
-IDProperty *rna_ID_idprops(PointerRNA *ptr, bool create)
+IDProperty **rna_ID_idprops(PointerRNA *ptr)
 {
-  return IDP_GetProperties(ptr->data, create);
+  ID *id = (ID *)ptr->data;
+  return &id->properties;
 }
 
 void rna_ID_fake_user_set(PointerRNA *ptr, bool value)
@@ -510,9 +511,9 @@ void rna_ID_fake_user_set(PointerRNA *ptr, bool value)
   }
 }
 
-IDProperty *rna_PropertyGroup_idprops(PointerRNA *ptr, bool UNUSED(create))
+IDProperty **rna_PropertyGroup_idprops(PointerRNA *ptr)
 {
-  return ptr->data;
+  return (IDProperty **)&ptr->data;
 }
 
 void rna_PropertyGroup_unregister(Main *UNUSED(bmain), StructRNA *type)
@@ -1162,12 +1163,12 @@ static PointerRNA rna_IDPreview_get(PointerRNA *ptr)
   return rna_pointer_inherit_refine(ptr, &RNA_ImagePreview, prv_img);
 }
 
-static IDProperty *rna_IDPropertyWrapPtr_idprops(PointerRNA *ptr, bool UNUSED(create))
+static IDProperty **rna_IDPropertyWrapPtr_idprops(PointerRNA *ptr)
 {
   if (ptr == NULL) {
     return NULL;
   }
-  return ptr->data;
+  return (IDProperty **)&ptr->data;
 }
 
 static void rna_Library_version_get(PointerRNA *ptr, int *value)