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, 79 insertions, 65 deletions

diff --git a/source/blender/editors/space_file/filelist.cc b/source/blender/editors/space_file/filelist.cc
index 9ca5b1da7da..c4d99d41a60 100644
--- a/source/blender/editors/space_file/filelist.cc
+++ b/source/blender/editors/space_file/filelist.cc
@@ -43,6 +43,8 @@
 
 #include "BKE_asset.h"
 #include "BKE_asset_library.h"
+#include "BKE_asset_library.hh"
+#include "BKE_asset_representation.hh"
 #include "BKE_context.h"
 #include "BKE_global.h"
 #include "BKE_icons.h"
@@ -78,6 +80,8 @@
 #include "file_intern.h"
 #include "filelist.h"
 
+using namespace blender;
+
 #define FILEDIR_NBR_ENTRIES_UNSET -1
 
 /* ------------------FILELIST------------------------ */
@@ -95,7 +99,7 @@ struct FileListInternEntry {
   /** Optional argument for shortcuts, aliases etc. */
   char *redirection_path;
   /** not strictly needed, but used during sorting, avoids to have to recompute it there... */
-  char *name;
+  const char *name;
   bool free_name;
 
   /**
@@ -112,9 +116,8 @@ struct FileListInternEntry {
     PreviewImage *preview_image;
   } local_data;
 
-  /** When the file represents an asset read from another file, it is stored here.
-   * Owning pointer. */
-  AssetMetaData *imported_asset_data;
+  /* References an asset in the asset library storage. */
+  bke::AssetRepresentation *asset; /* Non-owning. */
 
   /* See #FILE_ENTRY_BLENDERLIB_NO_PREVIEW. */
   bool blenderlib_has_no_preview;
@@ -210,7 +213,7 @@ struct FileList {
   eFileSelectType type;
   /* The library this list was created for. Stored here so we know when to re-read. */
   AssetLibraryReference *asset_library_ref;
-  AssetLibrary *asset_library; /* Non-owning pointer. */
+  bke::AssetLibrary *asset_library; /* Non-owning. */
 
   short flags;
 
@@ -776,8 +779,10 @@ static bool is_filtered_id_file_type(const FileListInternEntry *file,
  */
 static AssetMetaData *filelist_file_internal_get_asset_data(const FileListInternEntry *file)
 {
-  const ID *local_id = file->local_data.id;
-  return local_id ? local_id->asset_data : file->imported_asset_data;
+  if (!file->asset) {
+    return nullptr;
+  }
+  return &file->asset->get_metadata();
 }
 
 static void prepare_filter_asset_library(const FileList *filelist, FileListFilter *filter)
@@ -1016,7 +1021,7 @@ void filelist_setindexer(FileList *filelist, const FileIndexerType *indexer)
 void filelist_set_asset_catalog_filter_options(
     FileList *filelist,
     eFileSel_Params_AssetCatalogVisibility catalog_visibility,
-    const bUUID *catalog_id)
+    const ::bUUID *catalog_id)
 {
   if (!filelist->filter_data.asset_catalog_filter) {
     /* There's no filter data yet. */
@@ -1362,7 +1367,7 @@ static bool filelist_checkdir_main_assets(struct FileList * /*filelist*/,
 static void filelist_entry_clear(FileDirEntry *entry)
 {
   if (entry->name && ((entry->flags & FILE_ENTRY_NAME_FREE) != 0)) {
-    MEM_freeN(entry->name);
+    MEM_freeN((char *)entry->name);
   }
   if (entry->relpath) {
     MEM_freeN(entry->relpath);
@@ -1399,8 +1404,13 @@ static void filelist_direntryarr_free(FileDirEntryArr *array)
   array->entries_filtered_num = FILEDIR_NBR_ENTRIES_UNSET;
 }
 
-static void filelist_intern_entry_free(FileListInternEntry *entry)
+static void filelist_intern_entry_free(FileList *filelist, FileListInternEntry *entry)
 {
+  if (entry->asset) {
+    BLI_assert(filelist->asset_library);
+    filelist->asset_library->remove_asset(*entry->asset);
+  }
+
   if (entry->relpath) {
     MEM_freeN(entry->relpath);
   }
@@ -1408,19 +1418,16 @@ static void filelist_intern_entry_free(FileListInternEntry *entry)
     MEM_freeN(entry->redirection_path);
   }
   if (entry->name && entry->free_name) {
-    MEM_freeN(entry->name);
-  }
-  /* If we own the asset-data (it was generated from external file data), free it. */
-  if (entry->imported_asset_data) {
-    BKE_asset_metadata_free(&entry->imported_asset_data);
+    MEM_freeN((char *)entry->name);
   }
   MEM_freeN(entry);
 }
 
-static void filelist_intern_free(FileListIntern *filelist_intern)
+static void filelist_intern_free(FileList *filelist)
 {
+  FileListIntern *filelist_intern = &filelist->filelist_intern;
   LISTBASE_FOREACH_MUTABLE (FileListInternEntry *, entry, &filelist_intern->entries) {
-    filelist_intern_entry_free(entry);
+    filelist_intern_entry_free(filelist, entry);
   }
   BLI_listbase_clear(&filelist_intern->entries);
 
@@ -1430,8 +1437,9 @@ static void filelist_intern_free(FileListIntern *filelist_intern)
 /**
  * \return the number of main files removed.
  */
-static int filelist_intern_free_main_files(FileListIntern *filelist_intern)
+static int filelist_intern_free_main_files(FileList *filelist)
 {
+  FileListIntern *filelist_intern = &filelist->filelist_intern;
   int removed_counter = 0;
   LISTBASE_FOREACH_MUTABLE (FileListInternEntry *, entry, &filelist_intern->entries) {
     if (!filelist_intern_entry_is_main_file(entry)) {
@@ -1439,7 +1447,7 @@ static int filelist_intern_free_main_files(FileListIntern *filelist_intern)
     }
 
     BLI_remlink(&filelist_intern->entries, entry);
-    filelist_intern_entry_free(entry);
+    filelist_intern_entry_free(filelist, entry);
     removed_counter++;
   }
 
@@ -1794,7 +1802,7 @@ void filelist_clear_ex(struct FileList *filelist,
     filelist_cache_clear(&filelist->filelist_cache, filelist->filelist_cache.size);
   }
 
-  filelist_intern_free(&filelist->filelist_intern);
+  filelist_intern_free(filelist);
 
   filelist_direntryarr_free(&filelist->filelist);
 
@@ -1822,7 +1830,7 @@ static void filelist_clear_main_files(FileList *filelist,
     filelist_cache_clear(&filelist->filelist_cache, filelist->filelist_cache.size);
   }
 
-  const int removed_files = filelist_intern_free_main_files(&filelist->filelist_intern);
+  const int removed_files = filelist_intern_free_main_files(filelist);
 
   filelist->filelist.entries_num -= removed_files;
   filelist->filelist.entries_filtered_num = FILEDIR_NBR_ENTRIES_UNSET;
@@ -1881,7 +1889,7 @@ void filelist_free(struct FileList *filelist)
 
 AssetLibrary *filelist_asset_library(FileList *filelist)
 {
-  return filelist->asset_library;
+  return reinterpret_cast<::AssetLibrary *>(filelist->asset_library);
 }
 
 void filelist_freelib(struct FileList *filelist)
@@ -1897,11 +1905,15 @@ BlendHandle *filelist_lib(struct FileList *filelist)
   return filelist->libfiledata;
 }
 
-static char *fileentry_uiname(const char *root,
-                              const char *relpath,
-                              const eFileSel_File_Types typeflag,
-                              char *buff)
+static const char *fileentry_uiname(const char *root, FileListInternEntry *entry, char *buff)
 {
+  if (entry->asset) {
+    const StringRefNull asset_name = entry->asset->get_name();
+    return BLI_strdupn(asset_name.c_str(), asset_name.size());
+  }
+
+  const char *relpath = entry->relpath;
+  const eFileSel_File_Types typeflag = entry->typeflag;
   char *name = nullptr;
 
   if (typeflag & FILE_TYPE_FTFONT && !(typeflag & FILE_TYPE_BLENDERLIB)) {
@@ -2042,10 +2054,7 @@ static FileDirEntry *filelist_file_create_entry(FileList *filelist, const int in
     ret->redirection_path = BLI_strdup(entry->redirection_path);
   }
   ret->id = entry->local_data.id;
-  ret->asset_data = entry->imported_asset_data ? entry->imported_asset_data : nullptr;
-  if (ret->id && (ret->asset_data == nullptr)) {
-    ret->asset_data = ret->id->asset_data;
-  }
+  ret->asset = reinterpret_cast<::AssetRepresentation *>(entry->asset);
   /* For some file types the preview is already available. */
   if (entry->local_data.preview_image &&
       BKE_previewimg_is_finished(entry->local_data.preview_image, ICON_SIZE_PREVIEW)) {
@@ -2996,8 +3005,13 @@ static FileListInternEntry *filelist_readjob_list_lib_group_create(const int idc
   return entry;
 }
 
-static void filelist_readjob_list_lib_add_datablock(ListBase *entries,
-                                                    const BLODataBlockInfo *datablock_info,
+/**
+ * \warning: This "steals" the asset metadata from \a datablock_info. Not great design but fixing
+ *           this requires redesigning things on the caller side for proper ownership management.
+ */
+static void filelist_readjob_list_lib_add_datablock(FileList *filelist,
+                                                    ListBase *entries,
+                                                    BLODataBlockInfo *datablock_info,
                                                     const bool prefix_relpath_with_group_name,
                                                     const int idcode,
                                                     const char *group_name)
@@ -3010,21 +3024,29 @@ static void filelist_readjob_list_lib_add_datablock(ListBase *entries,
     entry->relpath = BLI_strdup(datablock_info->name);
   }
   entry->typeflag |= FILE_TYPE_BLENDERLIB;
-
   if (datablock_info) {
     entry->blenderlib_has_no_preview = datablock_info->no_preview_found;
 
     if (datablock_info->asset_data) {
       entry->typeflag |= FILE_TYPE_ASSET;
-      /* Moves ownership! */
-      entry->imported_asset_data = datablock_info->asset_data;
+
+      if (filelist->asset_library) {
+        /** XXX Moving out the asset metadata like this isn't great. */
+        std::unique_ptr metadata = BKE_asset_metadata_move_to_unique_ptr(
+            datablock_info->asset_data);
+        BKE_asset_metadata_free(&datablock_info->asset_data);
+
+        entry->asset = &filelist->asset_library->add_external_asset(datablock_info->name,
+                                                                    std::move(metadata));
+      }
     }
   }
   entry->blentype = idcode;
   BLI_addtail(entries, entry);
 }
 
-static void filelist_readjob_list_lib_add_datablocks(ListBase *entries,
+static void filelist_readjob_list_lib_add_datablocks(FileList *filelist,
+                                                     ListBase *entries,
                                                      LinkNode *datablock_infos,
                                                      const bool prefix_relpath_with_group_name,
                                                      const int idcode,
@@ -3033,19 +3055,21 @@ static void filelist_readjob_list_lib_add_datablocks(ListBase *entries,
   for (LinkNode *ln = datablock_infos; ln; ln = ln->next) {
     struct BLODataBlockInfo *datablock_info = static_cast<BLODataBlockInfo *>(ln->link);
     filelist_readjob_list_lib_add_datablock(
-        entries, datablock_info, prefix_relpath_with_group_name, idcode, group_name);
+        filelist, entries, datablock_info, prefix_relpath_with_group_name, idcode, group_name);
   }
 }
 
 static void filelist_readjob_list_lib_add_from_indexer_entries(
+    FileList *filelist,
     ListBase *entries,
     const FileIndexerEntries *indexer_entries,
     const bool prefix_relpath_with_group_name)
 {
   for (const LinkNode *ln = indexer_entries->entries; ln; ln = ln->next) {
-    const FileIndexerEntry *indexer_entry = (const FileIndexerEntry *)ln->link;
+    FileIndexerEntry *indexer_entry = static_cast<FileIndexerEntry *>(ln->link);
     const char *group_name = BKE_idtype_idcode_to_name(indexer_entry->idcode);
-    filelist_readjob_list_lib_add_datablock(entries,
+    filelist_readjob_list_lib_add_datablock(filelist,
+                                            entries,
                                             &indexer_entry->datablock_info,
                                             prefix_relpath_with_group_name,
                                             indexer_entry->idcode,
@@ -3073,7 +3097,8 @@ typedef struct FileIndexer {
   void *user_data;
 } FileIndexer;
 
-static int filelist_readjob_list_lib_populate_from_index(ListBase *entries,
+static int filelist_readjob_list_lib_populate_from_index(FileList *filelist,
+                                                         ListBase *entries,
                                                          const ListLibOptions options,
                                                          const int read_from_index,
                                                          const FileIndexerEntries *indexer_entries)
@@ -3085,11 +3110,12 @@ static int filelist_readjob_list_lib_populate_from_index(ListBase *entries,
     navigate_to_parent_len = 1;
   }
 
-  filelist_readjob_list_lib_add_from_indexer_entries(entries, indexer_entries, true);
+  filelist_readjob_list_lib_add_from_indexer_entries(filelist, entries, indexer_entries, true);
   return read_from_index + navigate_to_parent_len;
 }
 
-static int filelist_readjob_list_lib(const char *root,
+static int filelist_readjob_list_lib(FileList *filelist,
+                                     const char *root,
                                      ListBase *entries,
                                      const ListLibOptions options,
                                      FileIndexer *indexer_runtime)
@@ -3128,7 +3154,7 @@ static int filelist_readjob_list_lib(const char *root,
         dir, &indexer_entries, &read_from_index, indexer_runtime->user_data);
     if (indexer_result == FILE_INDEXER_ENTRIES_LOADED) {
       int entries_read = filelist_readjob_list_lib_populate_from_index(
-          entries, options, read_from_index, &indexer_entries);
+          filelist, entries, options, read_from_index, &indexer_entries);
       ED_file_indexer_entries_clear(&indexer_entries);
       return entries_read;
     }
@@ -3158,7 +3184,8 @@ static int filelist_readjob_list_lib(const char *root,
     const int idcode = groupname_to_code(group);
     LinkNode *datablock_infos = BLO_blendhandle_get_datablock_info(
         libfiledata, idcode, options & LIST_LIB_ASSETS_ONLY, &datablock_len);
-    filelist_readjob_list_lib_add_datablocks(entries, datablock_infos, false, idcode, group);
+    filelist_readjob_list_lib_add_datablocks(
+        filelist, entries, datablock_infos, false, idcode, group);
     BLI_linklist_freeN(datablock_infos);
   }
   else {
@@ -3177,7 +3204,7 @@ static int filelist_readjob_list_lib(const char *root,
         LinkNode *group_datablock_infos = BLO_blendhandle_get_datablock_info(
             libfiledata, idcode, options & LIST_LIB_ASSETS_ONLY, &group_datablock_len);
         filelist_readjob_list_lib_add_datablocks(
-            entries, group_datablock_infos, true, idcode, group_name);
+            filelist, entries, group_datablock_infos, true, idcode, group_name);
         if (use_indexer) {
           ED_file_indexer_entries_extend_from_datablock_infos(
               &indexer_entries, group_datablock_infos, idcode);
@@ -3529,7 +3556,7 @@ static void filelist_readjob_recursive_dir_add_items(const bool do_lib,
         list_lib_options |= LIST_LIB_ASSETS_ONLY;
       }
       entries_num = filelist_readjob_list_lib(
-          subdir, &entries, list_lib_options, &indexer_runtime);
+          filelist, subdir, &entries, list_lib_options, &indexer_runtime);
       if (entries_num > 0) {
         is_lib = true;
       }
@@ -3550,7 +3577,7 @@ static void filelist_readjob_recursive_dir_add_items(const bool do_lib,
       MEM_freeN(entry->relpath);
       entry->relpath = BLI_strdup(dir + 2); /* + 2 to remove '//'
                                              * added by BLI_path_rel to rel_subdir. */
-      entry->name = fileentry_uiname(root, entry->relpath, entry->typeflag, dir);
+      entry->name = fileentry_uiname(root, entry, dir);
       entry->free_name = true;
 
       if (filelist_readjob_should_recurse_into_entry(
@@ -3626,20 +3653,6 @@ static void filelist_readjob_lib(FileListReadJob *job_params,
   filelist_readjob_do(true, job_params, stop, do_update, progress);
 }
 
-static void filelist_asset_library_path(const FileListReadJob *job_params,
-                                        char r_library_root_path[FILE_MAX])
-{
-  if (job_params->filelist->type == FILE_MAIN_ASSET) {
-    /* For the "Current File" library (#FILE_MAIN_ASSET) we get the asset library root path based
-     * on main. */
-    BKE_asset_library_find_suitable_root_path_from_main(job_params->current_main,
-                                                        r_library_root_path);
-  }
-  else {
-    BLI_strncpy(r_library_root_path, job_params->tmp_filelist->filelist.root, FILE_MAX);
-  }
-}
-
 /**
  * Load asset library data, which currently means loading the asset catalogs for the library.
  */
@@ -3657,12 +3670,10 @@ static void filelist_readjob_load_asset_library_data(FileListReadJob *job_params
     return;
   }
 
-  char library_root_path[FILE_MAX];
-  filelist_asset_library_path(job_params, library_root_path);
-
   /* Load asset catalogs, into the temp filelist for thread-safety.
    * #filelist_readjob_endjob() will move it into the real filelist. */
-  tmp_filelist->asset_library = BKE_asset_library_load(library_root_path);
+  tmp_filelist->asset_library = BKE_asset_library_load(job_params->current_main,
+                                                       *job_params->filelist->asset_library_ref);
   *do_update = true;
 }
 
@@ -3699,6 +3710,9 @@ static void filelist_readjob_main_assets_add_items(FileListReadJob *job_params,
     entry->local_data.preview_image = BKE_asset_metadata_preview_get_from_id(id_iter->asset_data,
                                                                              id_iter);
     entry->local_data.id = id_iter;
+    if (filelist->asset_library) {
+      entry->asset = &filelist->asset_library->add_local_id_asset(*id_iter);
+    }
     entries_num++;
     BLI_addtail(&tmp_entries, entry);
   }