RNA: Cleanup PointerRNA struct

The old layout of `PointerRNA` was confusing for historic reasons:
```
typedef struct PointerRNA {
  struct {
    void *data;
  } id;

  struct StructRNA *type;
  void *data;
} PointerRNA;
```

This patch updates it to:
```
typedef struct PointerRNA {
  struct ID *owner_id;
  struct StructRNA *type;
  void *data;
} PointerRNA;
```

Throughout the code base `id.data` was replaced with `owner_id`.
Furthermore, many explicit pointer type casts were added which
were implicit before. Some type casts to `ID *` were removed.

Reviewers: brecht, campbellbarton

Differential Revision: https://developer.blender.org/D5558

1 files changed, 4 insertions, 4 deletions

diff --git a/source/blender/makesrna/intern/rna_rna.c b/source/blender/makesrna/intern/rna_rna.c
index dc7e861421e..6e21d02c0b3 100644
--- a/source/blender/makesrna/intern/rna_rna.c
+++ b/source/blender/makesrna/intern/rna_rna.c
@@ -388,10 +388,10 @@ void rna_builtin_properties_begin(CollectionPropertyIterator *iter, PointerRNA *
   newptr.data = ptr->type;
 
   if (ptr->type->flag & STRUCT_ID) {
-    newptr.id.data = ptr->data;
+    newptr.owner_id = ptr->data;
   }
   else {
-    newptr.id.data = NULL;
+    newptr.owner_id = NULL;
   }
 
   iter->parent = newptr;
@@ -414,7 +414,7 @@ int rna_builtin_properties_lookup_string(PointerRNA *ptr, const char *key, Point
 {
   StructRNA *srna;
   PropertyRNA *prop;
-  PointerRNA propptr = {{NULL}};
+  PointerRNA propptr = {NULL};
 
   srna = ptr->type;
 
@@ -1229,7 +1229,7 @@ static bool rna_property_override_diff_propptr_validate_diffing(PointerRNA *prop
   }
 
   if (*r_is_id) {
-    BLI_assert(propptr_a->data == propptr_a->id.data && propptr_b->data == propptr_b->id.data);
+    BLI_assert(propptr_a->data == propptr_a->owner_id && propptr_b->data == propptr_b->owner_id);
   }
 
   return is_valid_for_diffing;