PyAPI: utility functions for parsing typed RNA arguments

These functions can be used with PyArg_ParseTupleAndKeywords
(and related functions) to take typed RNA arguments without
having to extract and type-check them separately.

No functional changes, extracted from D13126.

2 files changed, 71 insertions, 0 deletions

diff --git a/source/blender/python/intern/bpy_rna.c b/source/blender/python/intern/bpy_rna.c
index 5db66405403..11b584b692d 100644
--- a/source/blender/python/intern/bpy_rna.c
+++ b/source/blender/python/intern/bpy_rna.c
@@ -7872,6 +7872,50 @@ StructRNA *pyrna_struct_as_srna(PyObject *self, const bool parent, const char *e
   return srna;
 }
 
+const PointerRNA *pyrna_struct_as_ptr(PyObject *py_obj, const StructRNA *srna)
+{
+  BPy_StructRNA *bpy_srna = (BPy_StructRNA *)py_obj;
+  if (!BPy_StructRNA_Check(py_obj) || !RNA_struct_is_a(bpy_srna->ptr.type, srna)) {
+    PyErr_Format(PyExc_TypeError,
+                 "Expected a \"bpy.types.%.200s\" not a \"%.200s\"",
+                 RNA_struct_identifier(srna),
+                 Py_TYPE(py_obj)->tp_name);
+    return NULL;
+  }
+  PYRNA_STRUCT_CHECK_OBJ(bpy_srna);
+  return &bpy_srna->ptr;
+}
+
+const PointerRNA *pyrna_struct_as_ptr_or_null(PyObject *py_obj, const StructRNA *srna)
+{
+  if (py_obj == Py_None) {
+    return &PointerRNA_NULL;
+  }
+  return pyrna_struct_as_ptr(py_obj, srna);
+}
+
+int pyrna_struct_as_ptr_parse(PyObject *o, void *p)
+{
+  struct BPy_StructRNA_Parse *srna_parse = p;
+  BLI_assert(srna_parse->type != NULL);
+  srna_parse->ptr = pyrna_struct_as_ptr(o, srna_parse->type);
+  if (srna_parse->ptr == NULL) {
+    return 0;
+  }
+  return 1;
+}
+
+int pyrna_struct_as_ptr_or_null_parse(PyObject *o, void *p)
+{
+  struct BPy_StructRNA_Parse *srna_parse = p;
+  BLI_assert(srna_parse->type != NULL);
+  srna_parse->ptr = pyrna_struct_as_ptr_or_null(o, srna_parse->type);
+  if (srna_parse->ptr == NULL) {
+    return 0;
+  }
+  return 1;
+}
+
 /* Orphan functions, not sure where they should go. */
 StructRNA *srna_from_self(PyObject *self, const char *error_prefix)
 {
diff --git a/source/blender/python/intern/bpy_rna.h b/source/blender/python/intern/bpy_rna.h
index 573daac6e95..91fa0ea2c8d 100644
--- a/source/blender/python/intern/bpy_rna.h
+++ b/source/blender/python/intern/bpy_rna.h
@@ -187,6 +187,33 @@ PyObject *pyrna_prop_to_py(PointerRNA *ptr, PropertyRNA *prop);
 
 int pyrna_deferred_register_class(struct StructRNA *srna, PyTypeObject *py_class);
 
+const PointerRNA *pyrna_struct_as_ptr(PyObject *py_obj, const StructRNA *srna);
+const PointerRNA *pyrna_struct_as_ptr_or_null(PyObject *py_obj, const StructRNA *srna);
+
+/**
+ * Struct used for RNA argument parsing functions:
+ * - #pyrna_struct_as_ptr_parse
+ * - #pyrna_struct_as_ptr_or_null_parse
+ */
+struct BPy_StructRNA_Parse {
+  /** The struct RNA must match this type. */
+  StructRNA *type;
+  /** Result, may be `PointerRNA_NULL` if #pyrna_struct_as_ptr_or_null_parse is used. */
+  const PointerRNA *ptr;
+};
+
+/**
+ * Sets #BPy_StructRNA_Parse.ptr to the value in the #BPy_StructRNA.ptr (from `o`)
+ * or raise an error if the type isn't a #BPy_StructRNA.
+ *
+ * Use with #PyArg_ParseTuple's `O&` formatting.
+ */
+int pyrna_struct_as_ptr_parse(PyObject *o, void *p);
+/**
+ * A version of #pyrna_struct_as_ptr_parse that maps Python's `None` to #PointerRNA_NULL.
+ */
+int pyrna_struct_as_ptr_or_null_parse(PyObject *o, void *p);
+
 void pyrna_struct_type_extend_capi(struct StructRNA *srna,
                                    struct PyMethodDef *py_method,
                                    struct PyGetSetDef *py_getset);