DNA: initial DNA defaults support

This provides an API to access structs
with their members set to default values:

- DNA_struct_default_get(name)
- DNA_struct_default_alloc(name)

Currently this is only used for scene & view shading initialization,
eventually it can be used for RNA defaults and initializing
DNA struct members on file reading.

1 files changed, 46 insertions, 0 deletions

diff --git a/source/blender/makesdna/DNA_defaults.h b/source/blender/makesdna/DNA_defaults.h
new file mode 100644
index 00000000000..5b9297ce46a
--- /dev/null
+++ b/source/blender/makesdna/DNA_defaults.h
@@ -0,0 +1,46 @@
+
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup DNA
+ *
+ * \see dna_defaults.c for details on how to use this system.
+ */
+
+#ifndef __DNA_DEFAULTS_H__
+#define __DNA_DEFAULTS_H__
+
+#include "dna_type_offsets.h"
+
+extern const void *DNA_default_table[SDNA_TYPE_MAX];
+
+char *_DNA_struct_default_alloc_impl(const char *data_src, size_t size, const char *alloc_str);
+
+/**
+ * Wrap with macro that casts correctly.
+ */
+#define DNA_struct_default_get(struct_name) \
+  (const struct_name *)DNA_default_table[SDNA_TYPE_FROM_STRUCT(struct_name)]
+
+#define DNA_struct_default_alloc(struct_name) \
+  (struct_name *)_DNA_struct_default_alloc_impl( \
+      DNA_default_table[SDNA_TYPE_FROM_STRUCT(struct_name)], sizeof(struct_name), __func__)
+
+#endif /* __DNA_DEFAULTS_H__ */