UI: Rewrite asset shelf preview loading

- Fixes preview flickering on actions like undo/redo in the asset shelf (#93726), not yet for the
  file browser.
- Fixes #130861.

Makes the asset shelf use the asynchronous preview loading system of the UI instead of the file
browser one. The issues above where mostly caused by the file browser caching design.

The asset system and its UIs can now manage previews independently of the file browser back-end.
This is another step towards making the asset system independent of the file browser, see
https://developer.blender.org/docs/features/asset_system/fundamentals/from_file_browser_to_asset_system/.
Code to query asset previews through file browser types is removed.

Quite some work was done to prepare the UI preview system for this, to make it on par with the file
browser preview system. E.g.: 9d83061ed4, 315e7e04a8, 5055adc1c0, 16ab6111f7.

Note that the same change should be done to the asset/file browser, but this requires more work.

Pull Request: https://projects.blender.org/blender/blender/pulls/131871

source/blender/asset_system/AS_asset_representation.hh

@@ -26,6 +26,7 @@
 
 struct AssetMetaData;
 struct ID;
+struct PreviewImage;
 
 namespace blender::asset_system {
 
@@ -44,6 +45,7 @@ class AssetRepresentation : NonCopyable, NonMovable {
     std::string name;
     int id_type = 0;
     std::unique_ptr<AssetMetaData> metadata_ = nullptr;
+    PreviewImage *preview_ = nullptr;
   };
   std::variant<ExternalAsset, ID *> asset_;
 
@@ -63,7 +65,7 @@ class AssetRepresentation : NonCopyable, NonMovable {
   AssetRepresentation(StringRef relative_asset_path,
                       ID &id,
                       const AssetLibrary &owner_asset_library);
-  ~AssetRepresentation() = default;
+  ~AssetRepresentation();
 
   /**
    * Create a weak reference for this asset that can be written to files, but can break under a
@@ -72,6 +74,25 @@ class AssetRepresentation : NonCopyable, NonMovable {
    */
   AssetWeakReference make_weak_reference() const;
 
+  /**
+   * Makes sure the asset ready to load a preview, if necessary.
+   *
+   * For local IDs it calls #BKE_previewimg_id_ensure(). For others, this sets loading information
+   * to the preview but doesn't actually load it. To load it, attach its
+   * #PreviewImageRuntime::icon_id to a UI button (UI loads it asynchronously then) or call
+   * #BKE_previewimg_ensure() (not asynchronous).
+   *
+   * \returns the prepared preview, same as calling #get_preview().
+   */
+  void ensure_previewable();
+  /**
+   * Get the preview of this asset.
+   *
+   * This will only return a preview for local ID assets or after #ensure_previewable() was
+   * called.
+   */
+  PreviewImage *get_preview() const;
+
   StringRefNull get_name() const;
   ID_Type get_id_type() const;
   AssetMetaData &get_metadata() const;

source/blender/asset_system/CMakeLists.txt

@@ -48,6 +48,7 @@ set(LIB
   PRIVATE bf::blenkernel
   PRIVATE bf::blenlib
   PRIVATE bf::dna
+  PRIVATE bf::imbuf
   PRIVATE bf::intern::clog
   PRIVATE bf::intern::guardedalloc
 )

source/blender/asset_system/intern/asset_representation.cc

@@ -11,10 +11,14 @@
 #include "BLI_path_utils.hh"
 
 #include "BKE_blendfile.hh"
+#include "BKE_icons.h"
+#include "BKE_preview_image.hh"
 
 #include "DNA_ID.h"
 #include "DNA_asset_types.h"
 
+#include "IMB_thumbs.hh"
+
 #include "AS_asset_library.hh"
 #include "AS_asset_representation.hh"
 
@@ -27,7 +31,7 @@ AssetRepresentation::AssetRepresentation(StringRef relative_asset_path,
                                          const AssetLibrary &owner_asset_library)
     : owner_asset_library_(owner_asset_library),
       relative_identifier_(relative_asset_path),
-      asset_(AssetRepresentation::ExternalAsset{name, id_type, std::move(metadata)})
+      asset_(AssetRepresentation::ExternalAsset{name, id_type, std::move(metadata), nullptr})
 {
 }
 
@@ -43,11 +47,46 @@ AssetRepresentation::AssetRepresentation(StringRef relative_asset_path,
   }
 }
 
+AssetRepresentation::~AssetRepresentation()
+{
+  if (const ExternalAsset *extern_asset = std::get_if<ExternalAsset>(&asset_);
+      extern_asset && extern_asset->preview_)
+  {
+    BKE_previewimg_cached_release(this->full_path().c_str());
+  }
+}
+
 AssetWeakReference AssetRepresentation::make_weak_reference() const
 {
   return AssetWeakReference::make_reference(owner_asset_library_, relative_identifier_);
 }
 
+void AssetRepresentation::ensure_previewable()
+{
+  if (ID *id = this->local_id()) {
+    BKE_previewimg_id_ensure(id);
+  }
+
+  ExternalAsset &extern_asset = std::get<ExternalAsset>(asset_);
+
+  /* Use the full path as preview name, it's the only unique identifier we have. */
+  const std::string full_path = this->full_path();
+  /* Doesn't do the actual reading, just allocates and attaches the derrived load info. */
+  extern_asset.preview_ = BKE_previewimg_cached_thumbnail_read(
+      full_path.c_str(), full_path.c_str(), THB_SOURCE_BLEND, false);
+
+  BKE_icon_preview_ensure(nullptr, extern_asset.preview_);
+}
+
+PreviewImage *AssetRepresentation::get_preview() const
+{
+  if (const ID *id = this->local_id()) {
+    return BKE_previewimg_id_get(id);
+  }
+
+  return std::get<ExternalAsset>(asset_).preview_;
+}
+
 StringRefNull AssetRepresentation::get_name() const
 {
   if (const ID *id = this->local_id()) {

source/blender/blenkernel/intern/preview_image.cc

@@ -354,6 +354,10 @@ PreviewImage *BKE_previewimg_cached_thumbnail_read(const char *name,
 void BKE_previewimg_cached_release(const char *name)
 {
   BLI_assert(BLI_thread_is_main());
+  if (!gCachedPreviews) {
+    /* Static cache was already freed including all contained previews. Can happen on shutdown. */
+    return;
+  }
 
   PreviewImage *prv = (PreviewImage *)BLI_ghash_popkey(gCachedPreviews, name, MEM_freeN);
 

source/blender/editors/asset/ED_asset_handle.hh

@@ -14,8 +14,6 @@
 
 #pragma once
 
-#include "DNA_asset_types.h"
-
 struct AssetHandle;
 namespace blender::asset_system {
 class AssetRepresentation;
@@ -24,7 +22,5 @@ class AssetRepresentation;
 namespace blender::ed::asset {
 
 asset_system::AssetRepresentation *handle_get_representation(const AssetHandle *asset);
-int handle_get_preview_icon_id(const AssetHandle *asset);
-int handle_get_preview_or_type_icon_id(const AssetHandle *asset);
 
 }  // namespace blender::ed::asset

source/blender/editors/asset/ED_asset_list.hh

@@ -66,7 +66,6 @@ void iterate(const AssetLibraryReference &library_reference, AssetListIterFn fn)
  */
 void storage_fetch(const AssetLibraryReference *library_reference, const bContext *C);
 bool is_loaded(const AssetLibraryReference *library_reference);
-void previews_fetch(const AssetLibraryReference *library_reference, const bContext *C);
 /**
  * Clears this asset library and the "All" asset library for reload in both the static asset list
  * storage, as well as for all open asset browsers. Call this whenever the content of the given
@@ -104,12 +103,6 @@ AssetHandle asset_handle_get_by_index(const AssetLibraryReference *library_refer
 asset_system::AssetRepresentation *asset_get_by_index(
     const AssetLibraryReference &library_reference, int asset_index);
 
-bool asset_image_is_loading(const AssetLibraryReference *library_reference,
-                            const AssetHandle *asset_handle);
-void asset_preview_ensure_requested(const bContext &C,
-                                    const AssetLibraryReference *library_reference,
-                                    AssetHandle *asset_handle);
-
 /**
  * \return True if the region needs a UI redraw.
  */

source/blender/editors/asset/intern/asset_handle.cc

@@ -6,6 +6,8 @@
  * \ingroup edasset
  */
 
+#include "AS_asset_representation.hh"
+
 #include "DNA_space_types.h"
 
 #include "ED_fileselect.hh"
@@ -19,14 +21,4 @@ asset_system::AssetRepresentation *handle_get_representation(const AssetHandle *
   return asset->file_data->asset;
 }
 
-int handle_get_preview_icon_id(const AssetHandle *asset)
-{
-  return asset->file_data->preview_icon_id;
-}
-
-int handle_get_preview_or_type_icon_id(const AssetHandle *asset)
-{
-  return ED_file_icon(asset->file_data);
-}
-
 }  // namespace blender::ed::asset

source/blender/editors/asset/intern/asset_list.cc

@@ -16,6 +16,7 @@
 #include <string>
 
 #include "AS_asset_library.hh"
+#include "AS_asset_representation.hh"
 
 #include "BKE_context.hh"
 #include "BKE_screen.hh"
@@ -32,6 +33,7 @@
 #include "../space_file/file_indexer.hh"
 #include "../space_file/filelist.hh"
 
+#include "ED_asset_handle.hh"
 #include "ED_asset_indexer.hh"
 #include "ED_asset_list.hh"
 #include "ED_fileselect.hh"
@@ -77,32 +79,9 @@ class FileListWrapper {
   }
 };
 
-class PreviewTimer {
-  /* Non-owning! The Window-Manager registers and owns this. */
-  wmTimer *timer_ = nullptr;
-
- public:
-  void ensure_running(const bContext *C)
-  {
-    if (!timer_) {
-      timer_ = WM_event_timer_add_notifier(
-          CTX_wm_manager(C), CTX_wm_window(C), NC_ASSET | ND_ASSET_LIST_PREVIEW, 0.01);
-    }
-  }
-
-  void stop(const bContext *C)
-  {
-    if (timer_) {
-      WM_event_timer_remove_notifier(CTX_wm_manager(C), CTX_wm_window(C), timer_);
-      timer_ = nullptr;
-    }
-  }
-};
-
 class AssetList : NonCopyable {
   FileListWrapper filelist_;
   AssetLibraryReference library_ref_;
-  PreviewTimer previews_timer_;
 
  public:
   AssetList() = delete;
@@ -114,16 +93,12 @@ class AssetList : NonCopyable {
 
   void setup();
   void fetch(const bContext &C);
-  void update_previews(const bContext &C);
   void clear(const bContext *C);
 
   AssetHandle asset_get_by_index(int index) const;
 
-  void previews_job_update(const bContext *C);
   bool needs_refetch() const;
   bool is_loaded() const;
-  bool is_asset_preview_loading(const AssetHandle &asset) const;
-  void ensure_asset_preview_requested(const bContext &C, AssetHandle &asset);
   asset_system::AssetLibrary *asset_library() const;
   void iterate(AssetListIndexIterFn fn) const;
   void iterate(AssetListIterFn fn) const;
@@ -157,7 +132,6 @@ void AssetList::setup()
       true,
       "",
       "");
-  filelist_set_no_preview_auto_cache(files);
 
   const bool use_asset_indexer = !USER_EXPERIMENTAL_TEST(&U, no_asset_indexing);
   filelist_setindexer(files, use_asset_indexer ? &index::file_indexer_asset : &file_indexer_noop);
@@ -187,16 +161,6 @@ void AssetList::fetch(const bContext &C)
   filelist_filter(files);
 }
 
-void AssetList::update_previews(const bContext &C)
-{
-  if (filelist_cache_previews_enabled(filelist_)) {
-    /* Get newest loaded previews from the background thread queue. */
-    filelist_cache_previews_update(filelist_);
-  }
-  /* Update preview job, it might have to be stopped. */
-  this->previews_job_update(&C);
-}
-
 bool AssetList::needs_refetch() const
 {
   return filelist_needs_force_reset(filelist_) || filelist_needs_reading(filelist_);
@@ -207,23 +171,6 @@ bool AssetList::is_loaded() const
   return filelist_is_ready(filelist_);
 }
 
-void AssetList::ensure_asset_preview_requested(const bContext &C, AssetHandle &asset)
-{
-  /* Ensure previews are enabled. */
-  filelist_cache_previews_set(filelist_, true);
-
-  if (filelist_file_ensure_preview_requested(filelist_,
-                                             const_cast<FileDirEntry *>(asset.file_data)))
-  {
-    previews_timer_.ensure_running(&C);
-  }
-}
-
-bool AssetList::is_asset_preview_loading(const AssetHandle &asset) const
-{
-  return filelist_file_is_preview_pending(filelist_, asset.file_data);
-}
-
 asset_system::AssetLibrary *AssetList::asset_library() const
 {
   return reinterpret_cast<asset_system::AssetLibrary *>(filelist_asset_library(filelist_));
@@ -264,28 +211,6 @@ void AssetList::iterate(AssetListIterFn fn) const
   }
 }
 
-void AssetList::previews_job_update(const bContext *C)
-{
-  FileList *files = filelist_;
-
-  if (!filelist_cache_previews_enabled(files)) {
-    previews_timer_.stop(C);
-    return;
-  }
-
-  {
-    const bool previews_running = filelist_cache_previews_running(files) &&
-                                  !filelist_cache_previews_done(files);
-    if (previews_running) {
-      previews_timer_.ensure_running(C);
-    }
-    else {
-      /* Preview is not running, no need to keep generating update events! */
-      previews_timer_.stop(C);
-    }
-  }
-}
-
 void AssetList::clear(const bContext *C)
 {
   /* Based on #ED_fileselect_clear() */
@@ -466,14 +391,6 @@ bool is_loaded(const AssetLibraryReference *library_reference)
   return list->is_loaded();
 }
 
-void previews_fetch(const AssetLibraryReference *library_reference, const bContext *C)
-{
-  AssetList *list = lookup_list(*library_reference);
-  if (list) {
-    list->update_previews(*C);
-  }
-}
-
 void clear(const AssetLibraryReference *library_reference, const bContext *C)
 {
   AssetList *list = lookup_list(*library_reference);
@@ -556,21 +473,6 @@ asset_system::AssetRepresentation *asset_get_by_index(
   return reinterpret_cast<asset_system::AssetRepresentation *>(asset_handle.file_data->asset);
 }
 
-bool asset_image_is_loading(const AssetLibraryReference *library_reference,
-                            const AssetHandle *asset_handle)
-{
-  const AssetList *list = lookup_list(*library_reference);
-  return list->is_asset_preview_loading(*asset_handle);
-}
-
-void asset_preview_ensure_requested(const bContext &C,
-                                    const AssetLibraryReference *library_reference,
-                                    AssetHandle *asset_handle)
-{
-  AssetList *list = lookup_list(*library_reference);
-  list->ensure_asset_preview_requested(C, *asset_handle);
-}
-
 bool listen(const wmNotifier *notifier)
 {
   return AssetList::listen(*notifier);

source/blender/editors/asset/intern/asset_shelf_asset_view.cc

@@ -206,7 +206,7 @@ static std::optional<wmOperatorCallParams> create_activate_operator_params(
   return wmOperatorCallParams{ot, op_props, WM_OP_INVOKE_REGION_WIN};
 }
 
-void AssetViewItem::build_grid_tile(const bContext &C, uiLayout &layout) const
+void AssetViewItem::build_grid_tile(const bContext & /*C*/, uiLayout &layout) const
 {
   const AssetView &asset_view = reinterpret_cast<const AssetView &>(this->get_view());
   const AssetShelfType &shelf_type = *asset_view.shelf_.type;
@@ -254,13 +254,17 @@ void AssetViewItem::build_grid_tile(const bContext &C, uiLayout &layout) const
   /* Request preview when drawing. Grid views have an optimization to only draw items that are
    * actually visible, so only previews scrolled into view will be loaded this way. This reduces
    * total loading time and memory footprint. */
-  list::asset_preview_ensure_requested(C, &asset_view.library_ref_, &asset_handle);
+  asset_.ensure_previewable();
 
   const int preview_id = [&]() -> int {
-    if (list::asset_image_is_loading(&asset_view.library_ref_, &asset_handle)) {
+    /* Show loading icon while list is loading still. Previews might get pushed out of view again
+     * while the list grows, which can cause a lot of flickering. Note that this also means the
+     * actual loading of previews is delayed, because that only happens when a preview icon-ID is
+     * attached to a button. */
+    if (!list::is_loaded(&asset_view.library_ref_)) {
       return ICON_TEMP;
     }
-    return handle_get_preview_or_type_icon_id(&asset_handle);
+    return asset_preview_or_icon(asset_);
   }();
 
   ui::PreviewGridItem::build_grid_tile_button(layout, preview_id);
@@ -337,7 +341,6 @@ void build_asset_view(uiLayout &layout,
                       const bContext &C)
 {
   list::storage_fetch(&library_ref, &C);
-  list::previews_fetch(&library_ref, &C);
 
   const asset_system::AssetLibrary *library = list::library_get_once_available(library_ref);
   if (!library) {

source/blender/editors/asset/intern/asset_ui_utils.cc

@@ -12,6 +12,11 @@
 #include "AS_asset_representation.hh"
 
 #include "BKE_preferences.h"
+#include "BKE_preview_image.hh"
+
+#include "UI_interface_icons.hh"
+#include "UI_resources.hh"
+
 #include "DNA_userdef_types.h"
 #include "ED_asset.hh"
 #include "RNA_access.hh"
@@ -35,6 +40,33 @@ std::string asset_tooltip(const asset_system::AssetRepresentation &asset, const
   return complete_string;
 }
 
+BIFIconID asset_preview_icon_id(const asset_system::AssetRepresentation &asset)
+{
+  if (const PreviewImage *preview = asset.get_preview()) {
+    if (!BKE_previewimg_is_finished(preview, ICON_SIZE_PREVIEW)) {
+      /* Loading icon. */
+      return ICON_TEMP;
+    }
+
+    if (!BKE_previewimg_is_invalid(preview)) {
+      return preview->runtime->icon_id;
+    }
+  }
+
+  return ICON_NONE;
+}
+
+BIFIconID asset_preview_or_icon(const asset_system::AssetRepresentation &asset)
+{
+  const BIFIconID preview_icon = asset_preview_icon_id(asset);
+  if (preview_icon != ICON_NONE) {
+    return preview_icon;
+  }
+
+  /* Preview image not found or invalid. Use type icon. */
+  return UI_icon_from_idcode(asset.get_id_type());
+}
+
 const bUserAssetLibrary *get_asset_library_from_opptr(PointerRNA &ptr)
 {
   const int enum_value = RNA_enum_get(&ptr, "asset_library_reference");

source/blender/editors/include/ED_asset.hh

@@ -25,6 +25,9 @@
 #include "../asset/ED_asset_filter.hh"  // IWYU pragma: export
 #include "../asset/ED_asset_import.hh"  // IWYU pragma: export
 
+/** From UI_resources.hh. */
+using BIFIconID = int;
+
 struct PointerRNA;
 
 namespace blender::ed::asset {
@@ -32,6 +35,9 @@ namespace blender::ed::asset {
 std::string asset_tooltip(const asset_system::AssetRepresentation &asset,
                           bool include_name = true);
 
+BIFIconID asset_preview_icon_id(const asset_system::AssetRepresentation &asset);
+BIFIconID asset_preview_or_icon(const asset_system::AssetRepresentation &asset);
+
 void operatortypes_asset();
 
 /**

source/blender/editors/interface/templates/interface_template_asset_view.cc

@@ -58,12 +58,12 @@ static void asset_view_item_but_drag_set(uiBut *but, AssetHandle *asset_handle)
   UI_but_drag_set_asset(but,
                         asset,
                         import_method,
-                        asset::handle_get_preview_or_type_icon_id(asset_handle),
-                        asset::handle_get_preview_icon_id(asset_handle));
+                        asset::asset_preview_or_icon(*asset),
+                        asset::asset_preview_icon_id(*asset));
 }
 
 static void asset_view_draw_item(uiList *ui_list,
-                                 const bContext *C,
+                                 const bContext * /*C*/,
                                  uiLayout *layout,
                                  PointerRNA * /*dataptr*/,
                                  PointerRNA * /*itemptr*/,
@@ -77,6 +77,7 @@ static void asset_view_draw_item(uiList *ui_list,
 
   AssetHandle asset_handle = asset::list::asset_handle_get_by_index(&list_data->asset_library_ref,
                                                                     index);
+  asset_system::AssetRepresentation *asset = asset::handle_get_representation(&asset_handle);
 
   PointerRNA file_ptr = RNA_pointer_create_discrete(
       &list_data->screen->id,
@@ -84,28 +85,27 @@ static void asset_view_draw_item(uiList *ui_list,
       const_cast<FileDirEntry *>(asset_handle.file_data));
   uiLayoutSetContextPointer(layout, "active_file", &file_ptr);
 
-  asset::list::asset_preview_ensure_requested(*C, &list_data->asset_library_ref, &asset_handle);
+  asset->ensure_previewable();
 
   uiBlock *block = uiLayoutGetBlock(layout);
   const bool show_names = list_data->show_names;
   const float size_x = UI_preview_tile_size_x();
   const float size_y = show_names ? UI_preview_tile_size_y() : UI_preview_tile_size_y_no_label();
-  uiBut *but = uiDefIconTextBut(
-      block,
-      UI_BTYPE_PREVIEW_TILE,
-      0,
-      asset::handle_get_preview_icon_id(&asset_handle),
-      show_names ? asset::handle_get_representation(&asset_handle)->get_name().c_str() : "",
-      0,
-      0,
-      size_x,
-      size_y,
-      nullptr,
-      0,
-      0,
-      "");
+  uiBut *but = uiDefIconTextBut(block,
+                                UI_BTYPE_PREVIEW_TILE,
+                                0,
+                                asset::asset_preview_icon_id(*asset),
+                                show_names ? asset->get_name().c_str() : "",
+                                0,
+                                0,
+                                size_x,
+                                size_y,
+                                nullptr,
+                                0,
+                                0,
+                                "");
   ui_def_but_icon(but,
-                  asset::handle_get_preview_icon_id(&asset_handle),
+                  asset::asset_preview_icon_id(*asset),
                   /* NOLINTNEXTLINE: bugprone-suspicious-enum-usage */
                   UI_HAS_ICON | UI_BUT_ICON_PREVIEW);
   but->emboss = UI_EMBOSS_NONE;
@@ -256,7 +256,6 @@ void uiTemplateAssetView(uiLayout *layout,
   }
 
   asset::list::storage_fetch(&asset_library_ref, C);
-  asset::list::previews_fetch(&asset_library_ref, C);
   const int tot_items = asset::list::size(&asset_library_ref);
 
   populate_asset_collection(asset_library_ref, *assets_dataptr, assets_propname);

source/blender/editors/space_file/filelist.cc

@@ -304,12 +304,6 @@ enum {
   FL_NEED_SORTING = 1 << 4,
   FL_NEED_FILTERING = 1 << 5,
   FL_SORT_INVERT = 1 << 6,
-  /**
-   * By default, #filelist_file_cache_block() will attempt to load previews around the visible
-   * "window" of visible files. When this flag is set it won't do so, and each preview has to be
-   * queried through a #filelist_cache_previews_push() call.
-   */
-  FL_PREVIEWS_NO_AUTO_CACHE = 1 << 7,
 };
 
 /** #FileList.tags */
@@ -360,8 +354,6 @@ static int groupname_to_code(const char *group);
 
 static void filelist_cache_clear(FileListEntryCache *cache, size_t new_size);
 static bool filelist_intern_entry_is_main_file(const FileListInternEntry *intern_entry);
-static bool filelist_cache_previews_push(FileList *filelist, FileDirEntry *entry, const int index);
-static bool filelist_file_preview_load_poll(const FileDirEntry *entry);
 
 /* ********** Sort helpers ********** */
 
@@ -1166,35 +1158,6 @@ bool filelist_file_is_preview_pending(const FileList *filelist, const FileDirEnt
   return !filelist_ready || file->flags & FILE_ENTRY_PREVIEW_LOADING;
 }
 
-bool filelist_file_ensure_preview_requested(FileList *filelist, FileDirEntry *file)
-{
-  if (file->preview_icon_id) {
-    /* Already loaded. */
-    return false;
-  }
-
-  /* Wait with requests until file list reading is done, and previews may be loaded. */
-  if (!filelist_cache_previews_enabled(filelist)) {
-    return false;
-  }
-  /* #filelist_cache_previews_push() will repeat this, do here already to avoid lookup below. */
-  if (!filelist_file_preview_load_poll(file)) {
-    return false;
-  }
-
-  const int numfiles = filelist_files_ensure(filelist);
-  for (int i = 0; i < numfiles; i++) {
-    if (filelist->filelist_intern.filtered[i]->uid == file->uid) {
-      if (filelist_cache_previews_push(filelist, file, i)) {
-        return true;
-      }
-      break;
-    }
-  }
-
-  return false;
-}
-
 static FileDirEntry *filelist_geticon_get_file(FileList *filelist, const int index)
 {
   BLI_assert(G.background == false);
@@ -2115,11 +2078,6 @@ void filelist_setrecursion(FileList *filelist, const int recursion_level)
   }
 }
 
-void filelist_set_no_preview_auto_cache(FileList *filelist)
-{
-  filelist->flags |= FL_PREVIEWS_NO_AUTO_CACHE;
-}
-
 bool filelist_needs_force_reset(const FileList *filelist)
 {
   return (filelist->flags & (FL_FORCE_RESET | FL_FORCE_RESET_MAIN_FILES)) != 0;
@@ -2618,7 +2576,7 @@ bool filelist_file_cache_block(FileList *filelist, const int index)
 
   //  printf("Re-queueing previews...\n");
 
-  if ((cache->flags & FLC_PREVIEWS_ACTIVE) && !(filelist->flags & FL_PREVIEWS_NO_AUTO_CACHE)) {
+  if (cache->flags & FLC_PREVIEWS_ACTIVE) {
     /* Note we try to preview first images around given index - i.e. assumed visible ones. */
     int block_index = cache->block_cursor + (index - start_index);
     int offs_max = max_ii(end_index - index, index - start_index);
@@ -2641,11 +2599,6 @@ bool filelist_file_cache_block(FileList *filelist, const int index)
   return true;
 }
 
-bool filelist_cache_previews_enabled(const FileList *filelist)
-{
-  return (filelist->filelist_cache.flags & FLC_PREVIEWS_ACTIVE) != 0;
-}
-
 void filelist_cache_previews_set(FileList *filelist, const bool use_previews)
 {
   FileListEntryCache *cache = &filelist->filelist_cache;
@@ -2671,11 +2624,6 @@ void filelist_cache_previews_set(FileList *filelist, const bool use_previews)
   }
 }
 
-void filelist_cache_previews_ensure_running(FileList *filelist)
-{
-  filelist_cache_preview_ensure_running(&filelist->filelist_cache);
-}
-
 bool filelist_cache_previews_update(FileList *filelist)
 {
   FileListEntryCache *cache = &filelist->filelist_cache;

source/blender/editors/space_file/filelist.hh

@@ -87,7 +87,6 @@ bool filelist_file_is_preview_pending(const FileList *filelist, const FileDirEnt
  * \return True if a new preview request was pushed, false otherwise (e.g. because the preview is
  * already loaded, invalid or not supported).
  */
-bool filelist_file_ensure_preview_requested(FileList *filelist, FileDirEntry *file);
 ImBuf *filelist_get_preview_image(FileList *filelist, int index);
 ImBuf *filelist_file_get_preview_image(const FileDirEntry *file);
 ImBuf *filelist_geticon_special_file_image_ex(const FileDirEntry *file);
@@ -177,8 +176,6 @@ void filelist_file_cache_slidingwindow_set(FileList *filelist, size_t window_siz
  */
 bool filelist_file_cache_block(FileList *filelist, int index);
 
-void filelist_set_no_preview_auto_cache(FileList *filelist);
-
 bool filelist_needs_force_reset(const FileList *filelist);
 void filelist_tag_force_reset(FileList *filelist);
 void filelist_tag_force_reset_mainfiles(FileList *filelist);
@@ -237,9 +234,7 @@ void filelist_readjob_start(FileList *filelist, int space_notifier, const bConte
 void filelist_readjob_stop(FileList *filelist, wmWindowManager *wm);
 int filelist_readjob_running(FileList *filelist, wmWindowManager *wm);
 
-void filelist_cache_previews_ensure_running(FileList *filelist);
 bool filelist_cache_previews_update(FileList *filelist);
-bool filelist_cache_previews_enabled(const FileList *filelist);
 void filelist_cache_previews_set(FileList *filelist, bool use_previews);
 bool filelist_cache_previews_running(FileList *filelist);
 bool filelist_cache_previews_done(FileList *filelist);