Assets: Initial Asset List as part of the Asset System design

Implements a basic, WIP version of the asset list. This is needed to
give the asset view UI template asset reading and displaying
functionality.

See:
* Asset System: Data Storage, Reading & UI Access - https://developer.blender.org/T88184

Especially the asset list internals should change. It uses the
File/Asset Browser's `FileList` API, which isn't really meant for access
from outside the File Browser. But as explained in T88184, it does a lot
of the stuff we currently need, so we (Sybren Stüvel and I) decided to
go this route for now. Work on a file-list rewrite which integrates well
with the asset system started in the `asset-system-filelist` branch.

Further includes:
* Operator to reload the asset list.
* New `bpy.types.AssetHandle.get_full_library_path()` function, which
  gets the full path of the asset via the asset-list.
* Changes to preview loading to prevent the preview loading job to run
  eternally for asset views. File Browsers have this issue too, but
  should be fixed separately.

3 files changed, 30 insertions, 10 deletions

diff --git a/source/blender/editors/space_file/filelist.c b/source/blender/editors/space_file/filelist.c
index c4b895dc54d..492a189fc81 100644
--- a/source/blender/editors/space_file/filelist.c
+++ b/source/blender/editors/space_file/filelist.c
@@ -334,6 +334,7 @@ typedef struct FileListEntryCache {
   /* Previews handling. */
   TaskPool *previews_pool;
   ThreadQueue *previews_done;
+  size_t previews_todo_count;
 } FileListEntryCache;
 
 /* FileListCache.flags */
@@ -1153,7 +1154,7 @@ ImBuf *filelist_file_getimage(const FileDirEntry *file)
   return file->preview_icon_id ? BKE_icon_imbuf_get_buffer(file->preview_icon_id) : NULL;
 }
 
-static ImBuf *filelist_geticon_image_ex(FileDirEntry *file)
+ImBuf *filelist_geticon_image_ex(const FileDirEntry *file)
 {
   ImBuf *ibuf = NULL;
 
@@ -1494,6 +1495,7 @@ static void filelist_cache_preview_runf(TaskPool *__restrict pool, void *taskdat
     /* That way task freeing function won't free th preview, since it does not own it anymore. */
     atomic_cas_ptr((void **)&preview_taskdata->preview, preview, NULL);
     BLI_thread_queue_push(cache->previews_done, preview);
+    atomic_fetch_and_sub_z(&cache->previews_todo_count, 1);
   }
 
   //  printf("%s: End (%d)...\n", __func__, threadid);
@@ -1520,6 +1522,7 @@ static void filelist_cache_preview_ensure_running(FileListEntryCache *cache)
   if (!cache->previews_pool) {
     cache->previews_pool = BLI_task_pool_create_background(cache, TASK_PRIORITY_LOW);
     cache->previews_done = BLI_thread_queue_init();
+    cache->previews_todo_count = 0;
 
     IMB_thumb_locks_acquire();
   }
@@ -1553,6 +1556,7 @@ static void filelist_cache_previews_free(FileListEntryCache *cache)
     BLI_task_pool_free(cache->previews_pool);
     cache->previews_pool = NULL;
     cache->previews_done = NULL;
+    cache->previews_todo_count = 0;
 
     IMB_thumb_locks_release();
   }
@@ -1633,6 +1637,8 @@ static void filelist_cache_init(FileListEntryCache *cache, size_t cache_size)
   cache->size = cache_size;
   cache->flags = FLC_IS_INIT;
 
+  cache->previews_todo_count = 0;
+
   /* We cannot translate from non-main thread, so init translated strings once from here. */
   IMB_thumb_ensure_translations();
 }
@@ -2384,7 +2390,8 @@ void filelist_cache_previews_set(FileList *filelist, const bool use_previews)
   if (use_previews && (filelist->flags & FL_IS_READY)) {
     cache->flags |= FLC_PREVIEWS_ACTIVE;
 
-    BLI_assert((cache->previews_pool == NULL) && (cache->previews_done == NULL));
+    BLI_assert((cache->previews_pool == NULL) && (cache->previews_done == NULL) &&
+               (cache->previews_todo_count == 0));
 
     //      printf("%s: Init Previews...\n", __func__);
 
@@ -2457,6 +2464,18 @@ bool filelist_cache_previews_running(FileList *filelist)
   return (cache->previews_pool != NULL);
 }
 
+bool filelist_cache_previews_done(FileList *filelist)
+{
+  FileListEntryCache *cache = &filelist->filelist_cache;
+  if ((cache->flags & FLC_PREVIEWS_ACTIVE) == 0) {
+    /* There are no previews. */
+    return false;
+  }
+
+  return (cache->previews_pool == NULL) || (cache->previews_done == NULL) ||
+         (cache->previews_todo_count == (size_t)BLI_thread_queue_len(cache->previews_done));
+}
+
 /* would recognize .blend as well */
 static bool file_is_blend_backup(const char *str)
 {
@@ -3432,7 +3451,7 @@ static void filelist_readjob_free(void *flrjv)
   MEM_freeN(flrj);
 }
 
-void filelist_readjob_start(FileList *filelist, const bContext *C)
+void filelist_readjob_start(FileList *filelist, const int space_notifier, const bContext *C)
 {
   Main *bmain = CTX_data_main(C);
   wmJob *wm_job;
@@ -3464,7 +3483,7 @@ void filelist_readjob_start(FileList *filelist, const bContext *C)
     filelist_readjob_endjob(flrj);
     filelist_readjob_free(flrj);
 
-    WM_event_add_notifier(C, NC_SPACE | ND_SPACE_FILE_LIST | NA_JOB_FINISHED, NULL);
+    WM_event_add_notifier(C, space_notifier | NA_JOB_FINISHED, NULL);
     return;
   }
 
@@ -3476,10 +3495,7 @@ void filelist_readjob_start(FileList *filelist, const bContext *C)
                        WM_JOB_PROGRESS,
                        WM_JOB_TYPE_FILESEL_READDIR);
   WM_jobs_customdata_set(wm_job, flrj, filelist_readjob_free);
-  WM_jobs_timer(wm_job,
-                0.01,
-                NC_SPACE | ND_SPACE_FILE_LIST,
-                NC_SPACE | ND_SPACE_FILE_LIST | NA_JOB_FINISHED);
+  WM_jobs_timer(wm_job, 0.01, space_notifier, space_notifier | NA_JOB_FINISHED);
   WM_jobs_callbacks(
       wm_job, filelist_readjob_startjob, NULL, filelist_readjob_update, filelist_readjob_endjob);
 
diff --git a/source/blender/editors/space_file/filelist.h b/source/blender/editors/space_file/filelist.h
index 0aace74e621..cb98cf6e74a 100644
--- a/source/blender/editors/space_file/filelist.h
+++ b/source/blender/editors/space_file/filelist.h
@@ -79,6 +79,7 @@ void filelist_init_icons(void);
 void filelist_free_icons(void);
 struct ImBuf *filelist_getimage(struct FileList *filelist, const int index);
 struct ImBuf *filelist_file_getimage(const FileDirEntry *file);
+struct ImBuf *filelist_geticon_image_ex(const FileDirEntry *file);
 struct ImBuf *filelist_geticon_image(struct FileList *filelist, const int index);
 int filelist_geticon(struct FileList *filelist, const int index, const bool is_main);
 
@@ -144,13 +145,16 @@ struct BlendHandle *filelist_lib(struct FileList *filelist);
 bool filelist_islibrary(struct FileList *filelist, char *dir, char **r_group);
 void filelist_freelib(struct FileList *filelist);
 
-void filelist_readjob_start(struct FileList *filelist, const struct bContext *C);
+void filelist_readjob_start(struct FileList *filelist,
+                            int space_notifier,
+                            const struct bContext *C);
 void filelist_readjob_stop(struct FileList *filelist, struct wmWindowManager *wm);
 int filelist_readjob_running(struct FileList *filelist, struct wmWindowManager *wm);
 
 bool filelist_cache_previews_update(struct FileList *filelist);
 void filelist_cache_previews_set(struct FileList *filelist, const bool use_previews);
 bool filelist_cache_previews_running(struct FileList *filelist);
+bool filelist_cache_previews_done(struct FileList *filelist);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/editors/space_file/space_file.c b/source/blender/editors/space_file/space_file.c
index e71c00e2312..31c7dee294b 100644
--- a/source/blender/editors/space_file/space_file.c
+++ b/source/blender/editors/space_file/space_file.c
@@ -367,7 +367,7 @@ static void file_refresh(const bContext *C, ScrArea *area)
 
   if (filelist_needs_reading(sfile->files)) {
     if (!filelist_pending(sfile->files)) {
-      filelist_readjob_start(sfile->files, C);
+      filelist_readjob_start(sfile->files, NC_SPACE | ND_SPACE_FILE_LIST, C);
     }
   }