Initial step for IDTypeInfo refactor 'cleanup' project.

Introduce new IDTypeInfo structure.

Each ID type will have its own, with some minimal basic common info,
and ID management callbacks.

This patch only does it for Object type, for demo/testing purpose.
Moving all existing IDs is a goal of next "cleanup Friday".

Note that BKE_idcode features should then be merged back into BKE_idtype -
but this will have to be done later, once all ID types have been properly
converted to the new system.

Another later TODO might be to try and add callbacks for file read/write,
and lib_query ID usages looper.

This is part of T73719.

Thanks to @brecht for initial idea, and reviewing the patch.

Differential Revision: https://developer.blender.org/D6966

1 files changed, 142 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_idtype.h b/source/blender/blenkernel/BKE_idtype.h
new file mode 100644
index 00000000000..ba0cf04dfc6
--- /dev/null
+++ b/source/blender/blenkernel/BKE_idtype.h
@@ -0,0 +1,142 @@
+/*
+ * 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.
+ */
+
+#ifndef __BKE_IDTYPE_H__
+#define __BKE_IDTYPE_H__
+
+/** \file
+ * \ingroup bke
+ *
+ * ID type structure, helping to factorize common operations and data for all data-block types.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct ID;
+struct Main;
+
+/** IDTypeInfo.flags. */
+enum {
+  /** Indicates that the given IDType does not support copying. */
+  IDTYPE_FLAGS_NO_COPY = 1 << 0,
+  /** Indicates that the given IDType does not support linking/appending from a library file. */
+  IDTYPE_FLAGS_NO_LIBLINKING = 1 << 1,
+  /** Indicates that the given IDType does not support making a library-linked ID local. */
+  IDTYPE_FLAGS_NO_MAKELOCAL = 1 << 2,
+};
+
+/* ********** Prototypes for IDTypeInfo callbacks. ********** */
+
+typedef void (*IDTypeInitDataFunction)(struct ID *id);
+
+/** \param flag: Copying options (see BKE_lib_id.h's LIB_ID_COPY_... flags for more). */
+typedef void (*IDTypeCopyDataFunction)(struct Main *bmain,
+                                       struct ID *id_dst,
+                                       const struct ID *id_src,
+                                       const int flag);
+
+typedef void (*IDTypeFreeDataFunction)(struct ID *id);
+
+/** \param flag: See BKE_lib_id.h's LIB_ID_MAKELOCAL_... flags. */
+typedef void (*IDTypeMakeLocalFunction)(struct Main *bmain, struct ID *id, const int flags);
+
+typedef struct IDTypeInfo {
+  /* ********** General IDType data. ********** */
+
+  /**
+   * Unique identifier of this type, either as a short or an array of two chars, see DNA_ID.h's
+   * ID_XX enums.
+   */
+  short id_code;
+  /**
+   * Bitflag matching id_code, used for filtering (e.g. in file browser), see DNA_ID.h's
+   * FILTER_ID_XX enums.
+   */
+  int id_filter;
+
+  /**
+   * Define the position of this data-block type in the virtual list of all data in a Main that is
+   * returned by `set_listbasepointers()`.
+   * Very important, this has to be unique and below INDEX_ID_MAX, see DNA_ID.h.
+   */
+  short main_listbase_index;
+
+  /** Memory size of a data-block of that type. */
+  size_t struct_size;
+
+  /** The user visible name for this data-block, also used as default name for a new data-block. */
+  const char *name;
+  /** Plural version of the user-visble name. */
+  const char *name_plural;
+  /** Translation context to use for UI messages related to that type of data-block. */
+  const char *translation_context;
+
+  /** Generic info flags about that data-block type. */
+  int flags;
+
+  /* ********** ID management callbacks ********** */
+
+  /* TODO: Note about callbacks: Ideally we could also handle here `BKE_lib_query`'s behavior, as
+   * well as read/write of files. However, this is a bit more involved than basic ID management
+   * callbacks, so we'll check on this later. */
+
+  /**
+   * Initialize a new, empty calloc'ed data-block. May be NULL if there is nothing to do.
+   */
+  IDTypeInitDataFunction init_data;
+
+  /**
+   * Copy the given data-block's data from source to destination. May be NULL if mere memcopy of
+   * the ID struct itself is enough.
+   */
+  IDTypeCopyDataFunction copy_data;
+
+  /**
+   * Free the data of the data-block (NOT the ID itself). May be NULL if there is nothing to do.
+   */
+  IDTypeFreeDataFunction free_data;
+
+  /**
+   * Make a linked data-block local. May be NULL if default behavior from
+   * `BKE_lib_id_make_local_generic()` is enough.
+   */
+  IDTypeMakeLocalFunction make_local;
+} IDTypeInfo;
+
+/* ********** Declaration of each IDTypeInfo. ********** */
+
+/* Those are defined in the respective BKE files. */
+extern IDTypeInfo IDType_ID_OB;
+
+/* ********** Helpers/Utils API. ********** */
+
+/* Module initialization. */
+void BKE_idtype_init(void);
+
+/* General helpers. */
+const struct IDTypeInfo *BKE_idtype_get_info_from_idcode(const short id_code);
+const struct IDTypeInfo *BKE_idtype_get_info_from_id(const struct ID *id);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __BKE_IDTYPE_H__ */