RNA: Allow structs to define tags for their properties

Adds support for defining a number of tags as part of the rna-struct
definition, which its properties can set similar to property-flags.
BPY supports setting these tags when defining custom properties too.

* To define tags for a struct (which its properties can use then), define the tags in an `EnumPropertyItem` array, and assign them to the struct using `RNA_def_struct_property_tags(...)`.
* To set tags for an RNA-property in C, use the new `RNA_def_property_tags(...)`.
* To set tags for an RNA-property in Python, use the newly added tags parameter. E.g. `bpy.props.FloatProperty(name="Some Float", tags={'SOME_TAG', 'ANOTHER_TAG'})`.

Actual usage of this will be added in a follow-up commit.

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_internal_types.h b/source/blender/makesrna/intern/rna_internal_types.h
index bf34d42116e..b43423464e9 100644
--- a/source/blender/makesrna/intern/rna_internal_types.h
+++ b/source/blender/makesrna/intern/rna_internal_types.h
@@ -159,6 +159,8 @@ struct PropertyRNA {
 	short flag_parameter;
 	/* Internal ("private") flags. */
 	short flag_internal;
+	/* The subset of StructRNA.prop_tag_defines values that applies to this property. */
+	short tags;
 
 	/* user readable name */
 	const char *name;
@@ -356,6 +358,9 @@ struct StructRNA {
 
 	/* various options */
 	int flag;
+	/* Each StructRNA type can define own tags which properties can set
+	 * (PropertyRNA.tags) for changed behavior based on struct-type. */
+	const EnumPropertyItem *prop_tag_defines;
 
 	/* user readable name */
 	const char *name;