Asset System: New core type to represent assets (`AssetRepresenation`)

Introduces a new `AssetRepresentation` type, as a runtime only container
to hold asset information. It is supposed to become _the_ main way to
represent and refer to assets in the asset system, see T87235. It can
store things like the asset name, asset traits, preview and other asset
metadata.

Technical documentation:
https://wiki.blender.org/wiki/Source/Architecture/Asset_System/Back_End#Asset_Representation.

By introducing a proper asset representation type, we do an important
step away from the previous, non-optimal representation of assets as
files in the file browser backend, and towards the asset system as
backend. It should replace the temporary & hacky `AssetHandle` design in
the near future. Note that the loading of asset data still happens
through the file browser backend, check the linked to Wiki page for more
information on that.

As a side-effect, asset metadata isn't stored in file browser file
entries when browsing with link/append anymore. Don't think this was
ever used, but scripts may have accessed this. Can be brought back if
there's a need for it.

1 files changed, 11 insertions, 4 deletions

diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index b2663b89333..b0311d63d44 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -540,6 +540,7 @@ static const EnumPropertyItem rna_enum_curve_display_handle_items[] = {
 #  include "BLI_string.h"
 
 #  include "BKE_anim_data.h"
+#  include "BKE_asset.h"
 #  include "BKE_brush.h"
 #  include "BKE_colortools.h"
 #  include "BKE_context.h"
@@ -2761,18 +2762,24 @@ static PointerRNA rna_FileBrowser_FileSelectEntry_asset_data_get(PointerRNA *ptr
 {
   const FileDirEntry *entry = ptr->data;
 
+  if (!entry->asset) {
+    return PointerRNA_NULL;
+  }
+
+  AssetMetaData *asset_data = BKE_asset_representation_metadata_get(entry->asset);
+
   /* Note that the owning ID of the RNA pointer (`ptr->owner_id`) has to be set carefully:
    * Local IDs (`entry->id`) own their asset metadata themselves. Asset metadata from other blend
    * files are owned by the file browser (`entry`). Only if this is set correctly, we can tell from
    * the metadata RNA pointer if the metadata is stored locally and can thus be edited or not. */
 
-  if (entry->id) {
+  if (BKE_asset_representation_is_local_id(entry->asset)) {
     PointerRNA id_ptr;
     RNA_id_pointer_create(entry->id, &id_ptr);
-    return rna_pointer_inherit_refine(&id_ptr, &RNA_AssetMetaData, entry->asset_data);
+    return rna_pointer_inherit_refine(&id_ptr, &RNA_AssetMetaData, asset_data);
   }
 
-  return rna_pointer_inherit_refine(ptr, &RNA_AssetMetaData, entry->asset_data);
+  return rna_pointer_inherit_refine(ptr, &RNA_AssetMetaData, asset_data);
 }
 
 static int rna_FileBrowser_FileSelectEntry_name_editable(PointerRNA *ptr, const char **r_info)
@@ -2782,7 +2789,7 @@ static int rna_FileBrowser_FileSelectEntry_name_editable(PointerRNA *ptr, const
   /* This actually always returns 0 (the name is never editable) but we want to get a disabled
    * message returned to `r_info` in some cases. */
 
-  if (entry->asset_data) {
+  if (entry->asset) {
     PointerRNA asset_data_ptr = rna_FileBrowser_FileSelectEntry_asset_data_get(ptr);
     /* Get disabled hint from asset metadata polling. */
     rna_AssetMetaData_editable(&asset_data_ptr, r_info);