Refactor BKE_bpath module.

The main goal of this refactor is to make BPath module use `IDTypeInfo`,
and move each ID-specific part of the `foreach_path` looper into their
own IDTypeInfo struct, using a new `foreach_path` callback.

Additionally, following improvements/cleanups are included:
* Attempt to get better, more consistent namings.
** In particular, move from `path_visitor` to more standard `foreach_path`.
* Update and extend documentation.
** API doc was moved to header, according to recent discussions on this
   topic.
* Remove `BKE_bpath_relocate_visitor` from API, this is specific
  callback that belongs in `lib_id.c` user code.

NOTE: This commit is expected to be 100% non-behavioral-change. This
implies that several potential further changes were only noted as
comments (like using a more generic solution for
`lib_id_library_local_paths`, addressing inconsistencies like path of
packed libraries always being skipped, regardless of the
`BKE_BPATH_FOREACH_PATH_SKIP_PACKED` `eBPathForeachFlag` flag value,
etc.).

NOTE: basic unittests were added to master already in
rBdcc500e5a265093bc9cc.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D13381

1 files changed, 8 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_idtype.h b/source/blender/blenkernel/BKE_idtype.h
index 05441f06eb8..7a7f32fe838 100644
--- a/source/blender/blenkernel/BKE_idtype.h
+++ b/source/blender/blenkernel/BKE_idtype.h
@@ -35,6 +35,7 @@ struct BlendDataReader;
 struct BlendExpander;
 struct BlendLibReader;
 struct BlendWriter;
+struct BPathForeachPathData;
 struct ID;
 struct LibraryForeachIDData;
 struct Main;
@@ -100,6 +101,8 @@ typedef void (*IDTypeForeachCacheFunction)(struct ID *id,
                                            IDTypeForeachCacheFunctionCallback function_callback,
                                            void *user_data);
 
+typedef void (*IDTypeForeachPathFunction)(struct ID *id, struct BPathForeachPathData *bpath_data);
+
 typedef struct ID *(*IDTypeEmbeddedOwnerGetFunction)(struct Main *bmain, struct ID *id);
 
 typedef void (*IDTypeBlendWriteFunction)(struct BlendWriter *writer,
@@ -190,6 +193,11 @@ typedef struct IDTypeInfo {
   IDTypeForeachCacheFunction foreach_cache;
 
   /**
+   * Iterator over all file paths of given ID.
+   */
+  IDTypeForeachPathFunction foreach_path;
+
+  /**
    * For embedded IDs, return their owner ID.
    */
   IDTypeEmbeddedOwnerGetFunction owner_get;