First step to handle missing libs/datablocks when reading a file.

Idea is, instead of ignoring completely missing linked datablocks, to
create void placeholders for them.

That way, you can work on your file, save it, and find again your missing data once
lib becomes available again. Or you can edit missing lib's path (in Outliner),
save and reload the file, and you are done.

Also, Outliner now shows broken libraries (and placeholders) with a 'broken lib' icon.

Future plans are also to be able to relocate missing libs and reload them at runtime.

Code notes:
    - Placeholder ID is just a regular datablock of same type as expected linked one,
      with 'default' data, and a LIB_MISSING bitflag set.
    - To allow creation of such datablocks, creation of datablocks in BKE was split in two step:
        + Allocation of memory itself.
        + Setting of all internal data to default values.

See also the design task (T43351).

Reviewed by @campbellbarton, thanks a bunch!

Differential Revision: https://developer.blender.org/D1394

1 files changed, 2 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_speaker.h b/source/blender/blenkernel/BKE_speaker.h
index 5d93b9844ab..5f30df1d6e3 100644
--- a/source/blender/blenkernel/BKE_speaker.h
+++ b/source/blender/blenkernel/BKE_speaker.h
@@ -29,7 +29,9 @@
  */
 
 struct Main;
+struct Speaker;
 
+void BKE_speaker_init(struct Speaker *spk);
 void *BKE_speaker_add(struct Main *bmain, const char *name);
 struct Speaker *BKE_speaker_copy(struct Speaker *spk);
 void BKE_speaker_make_local(struct Speaker *spk);