From 70474e1a7cc45a1b1cc08d39b3e472c88c8d3225 Mon Sep 17 00:00:00 2001
From: Julian Eisel <julian@blender.org>
Date: Mon, 14 Dec 2020 13:50:36 +0100
Subject: Asset System: Prepare File Browser backend for the Asset Browser

The Asset Browser will be a sub-editor of the File Browser. This prepares the
File Browser code for that.

**File-Lists**
* Support loading assets with metadata read from external files into the
  file-list.
* New main based file-list type, for the "Current File" asset library.
* Refresh file-list when switching between browse modes or asset libraries.
* Support empty file-lists (asset library with no assets).
* Store file previews as icons, so scripts can reference them via icon-id. See
  previous commit.

**Space Data**
* Introduce "browse mode" to differeniate between file and asset browsing.
* Add `FileAssetSelectParams` to `SpaceFile`, with `FileSelectParams` as base.
  Makes sure data is separated between asset and file browsing when switching
  between them. The active params can be obtained through
  `ED_fileselect_get_active_params()`.
* `FileAssetSelectParams` stores the currently visible asset library ID.
* Introduce file history abstraction so file and asset browsing can keep a
  separate history (previous and next directories).

**General**
* Option to only show asset data-blocks while file browsing (not exposed here).
* Add "active_file" context member, so scripts can get and display info about
  the active file.
* Add "active_id" context member, so `ED_OT_lib_id_load_custom_preview` can set
  a custom ID preview. (Only for "Current File" asset library)
* Expose some of `FileDirEntry` in RNA as (non-editable). That way scripts can
  obtain name, preview icon and asset-data.

Part of the first Asset Browser milestone. Check the #asset_browser_milestone_1
project milestone on developer.blender.org.

Differential Revision: https://developer.blender.org/D9724

Reviewed by: Bastien Montagne
---
 source/blender/blenkernel/intern/screen.c          |  11 +-
 source/blender/blenloader/intern/readfile.c        |   1 +
 source/blender/editors/include/ED_fileselect.h     |   7 +-
 source/blender/editors/space_file/file_intern.h    |   1 +
 source/blender/editors/space_file/file_ops.c       |   9 +-
 source/blender/editors/space_file/filelist.c       | 655 ++++++++++++++++-----
 source/blender/editors/space_file/filelist.h       |  19 +-
 source/blender/editors/space_file/filesel.c        | 188 ++++--
 source/blender/editors/space_file/space_file.c     | 139 ++++-
 source/blender/makesdna/DNA_space_types.h          | 125 +++-
 source/blender/makesrna/RNA_access.h               |   2 +
 source/blender/makesrna/RNA_enum_types.h           |   1 +
 source/blender/makesrna/intern/rna_space.c         | 241 +++++++-
 .../windowmanager/intern/wm_operator_props.c       |   2 +
 14 files changed, 1159 insertions(+), 242 deletions(-)

diff --git a/source/blender/blenkernel/intern/screen.c b/source/blender/blenkernel/intern/screen.c
index ae817c46931..52c41c9fd05 100644
--- a/source/blender/blenkernel/intern/screen.c
+++ b/source/blender/blenkernel/intern/screen.c
@@ -1266,6 +1266,9 @@ static void write_area_regions(BlendWriter *writer, ScrArea *area)
       if (sfile->params) {
         BLO_write_struct(writer, FileSelectParams, sfile->params);
       }
+      if (sfile->asset_params) {
+        BLO_write_struct(writer, FileAssetSelectParams, sfile->asset_params);
+      }
     }
     else if (sl->spacetype == SPACE_SEQ) {
       BLO_write_struct(writer, SpaceSeq, sl);
@@ -1663,11 +1666,14 @@ static void direct_link_area(BlendDataReader *reader, ScrArea *area)
        * plus, it isn't saved to files yet!
        */
       sfile->folders_prev = sfile->folders_next = NULL;
+      BLI_listbase_clear(&sfile->folder_histories);
       sfile->files = NULL;
       sfile->layout = NULL;
       sfile->op = NULL;
       sfile->previews_timer = NULL;
+      sfile->tags = 0;
       BLO_read_data_address(reader, &sfile->params);
+      BLO_read_data_address(reader, &sfile->asset_params);
     }
     else if (sl->spacetype == SPACE_CLIP) {
       SpaceClip *sclip = (SpaceClip *)sl;
@@ -1751,8 +1757,11 @@ void BKE_screen_area_blend_read_lib(BlendLibReader *reader, ID *parent_id, ScrAr
         }
         break;
       }
-      case SPACE_FILE:
+      case SPACE_FILE: {
+        SpaceFile *sfile = (SpaceFile *)sl;
+        sfile->tags |= FILE_TAG_REBUILD_MAIN_FILES;
         break;
+      }
       case SPACE_ACTION: {
         SpaceAction *saction = (SpaceAction *)sl;
         bDopeSheet *ads = &saction->ads;
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index a3e793038f7..bccc7150523 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -2751,6 +2751,7 @@ static void lib_link_workspace_layout_restore(struct IDNameLib_Map *id_map,
           SpaceFile *sfile = (SpaceFile *)sl;
           sfile->op = NULL;
           sfile->previews_timer = NULL;
+          sfile->tags = FILE_TAG_REBUILD_MAIN_FILES;
         }
         else if (sl->spacetype == SPACE_ACTION) {
           SpaceAction *saction = (SpaceAction *)sl;
diff --git a/source/blender/editors/include/ED_fileselect.h b/source/blender/editors/include/ED_fileselect.h
index a5a8df916d6..3288cf11cb0 100644
--- a/source/blender/editors/include/ED_fileselect.h
+++ b/source/blender/editors/include/ED_fileselect.h
@@ -29,6 +29,7 @@ extern "C" {
 
 struct ARegion;
 struct FileSelectParams;
+struct FileAssetSelectParams;
 struct Scene;
 struct ScrArea;
 struct SpaceFile;
@@ -103,14 +104,14 @@ struct rcti;
 
 struct FileSelectParams *ED_fileselect_ensure_active_params(struct SpaceFile *sfile);
 struct FileSelectParams *ED_fileselect_get_active_params(const struct SpaceFile *sfile);
+struct FileSelectParams *ED_fileselect_get_file_params(const struct SpaceFile *sfile);
+struct FileAssetSelectParams *ED_fileselect_get_asset_params(const struct SpaceFile *sfile);
 
 void ED_fileselect_set_params_from_userdef(struct SpaceFile *sfile);
 void ED_fileselect_params_to_userdef(struct SpaceFile *sfile,
                                      const int temp_win_size[],
                                      const bool is_maximized);
 
-void ED_fileselect_reset_params(struct SpaceFile *sfile);
-
 void ED_fileselect_init_layout(struct SpaceFile *sfile, struct ARegion *region);
 
 FileLayout *ED_fileselect_get_layout(struct SpaceFile *sfile, struct ARegion *region);
@@ -142,6 +143,8 @@ void ED_fileselect_exit(struct wmWindowManager *wm,
                         struct Scene *owner_scene,
                         struct SpaceFile *sfile);
 
+bool ED_fileselect_is_asset_browser(const struct SpaceFile *sfile);
+
 void ED_fileselect_window_params_get(const struct wmWindow *win,
                                      int win_size[2],
                                      bool *is_maximized);
diff --git a/source/blender/editors/space_file/file_intern.h b/source/blender/editors/space_file/file_intern.h
index b459c02d9e5..a0e02681e0e 100644
--- a/source/blender/editors/space_file/file_intern.h
+++ b/source/blender/editors/space_file/file_intern.h
@@ -90,6 +90,7 @@ void file_sfile_to_operator(struct Main *bmain, struct wmOperator *op, struct Sp
 void file_operator_to_sfile(struct Main *bmain, struct SpaceFile *sfile, struct wmOperator *op);
 
 /* filesel.c */
+void fileselect_refresh_params(struct SpaceFile *sfile);
 void fileselect_file_set(SpaceFile *sfile, const int index);
 bool file_attribute_column_type_enabled(const FileSelectParams *params,
                                         FileAttributeColumnType column);
diff --git a/source/blender/editors/space_file/file_ops.c b/source/blender/editors/space_file/file_ops.c
index b98348307f3..8af84f65ced 100644
--- a/source/blender/editors/space_file/file_ops.c
+++ b/source/blender/editors/space_file/file_ops.c
@@ -930,6 +930,7 @@ void FILE_OT_select_all(wmOperatorType *ot)
 
 /* Note we could get rid of this one, but it's used by some addon so...
  * Does not hurt keeping it around for now. */
+/* TODO disallow bookmark editing in assets mode? */
 static int bookmark_select_exec(bContext *C, wmOperator *op)
 {
   Main *bmain = CTX_data_main(C);
@@ -1836,10 +1837,6 @@ static int file_previous_exec(bContext *C, wmOperator *UNUSED(op))
   FileSelectParams *params = ED_fileselect_get_active_params(sfile);
 
   if (params) {
-    if (!sfile->folders_next) {
-      sfile->folders_next = folderlist_new();
-    }
-
     folderlist_pushdir(sfile->folders_next, params->dir);
     folderlist_popdir(sfile->folders_prev, params->dir);
     folderlist_pushdir(sfile->folders_next, params->dir);
@@ -1874,10 +1871,6 @@ static int file_next_exec(bContext *C, wmOperator *UNUSED(unused))
   SpaceFile *sfile = CTX_wm_space_file(C);
   FileSelectParams *params = ED_fileselect_get_active_params(sfile);
   if (params) {
-    if (!sfile->folders_next) {
-      sfile->folders_next = folderlist_new();
-    }
-
     folderlist_pushdir(sfile->folders_prev, params->dir);
     folderlist_popdir(sfile->folders_next, params->dir);
 
diff --git a/source/blender/editors/space_file/filelist.c b/source/blender/editors/space_file/filelist.c
index e87142a7096..5dc5f741ac3 100644
--- a/source/blender/editors/space_file/filelist.c
+++ b/source/blender/editors/space_file/filelist.c
@@ -53,13 +53,17 @@
 #  include "BLI_winstuff.h"
 #endif
 
+#include "BKE_asset.h"
 #include "BKE_context.h"
 #include "BKE_global.h"
 #include "BKE_icons.h"
 #include "BKE_idtype.h"
+#include "BKE_lib_id.h"
 #include "BKE_main.h"
+#include "BKE_main_idmap.h"
 #include "BLO_readfile.h"
 
+#include "DNA_asset_types.h"
 #include "DNA_space_types.h"
 
 #include "ED_datafiles.h"
@@ -82,6 +86,8 @@
 
 #include "filelist.h"
 
+#define FILEDIR_NBR_ENTRIES_UNSET -1
+
 /* ----------------- FOLDERLIST (previous/next) -------------- */
 
 typedef struct FolderList {
@@ -89,12 +95,6 @@ typedef struct FolderList {
   char *foldername;
 } FolderList;
 
-ListBase *folderlist_new(void)
-{
-  ListBase *p = MEM_callocN(sizeof(*p), __func__);
-  return p;
-}
-
 void folderlist_popdir(struct ListBase *folderlist, char *dir)
 {
   const char *prev_dir;
@@ -117,6 +117,10 @@ void folderlist_popdir(struct ListBase *folderlist, char *dir)
 
 void folderlist_pushdir(ListBase *folderlist, const char *dir)
 {
+  if (!dir[0]) {
+    return;
+  }
+
   struct FolderList *folder, *previous_folder;
   previous_folder = folderlist->last;
 
@@ -153,7 +157,7 @@ int folderlist_clear_next(struct SpaceFile *sfile)
   struct FolderList *folder;
 
   /* if there is no folder_next there is nothing we can clear */
-  if (!sfile->folders_next) {
+  if (BLI_listbase_is_empty(sfile->folders_next)) {
     return 0;
   }
 
@@ -180,23 +184,79 @@ void folderlist_free(ListBase *folderlist)
   }
 }
 
-ListBase *folderlist_duplicate(ListBase *folderlist)
+static ListBase folderlist_duplicate(ListBase *folderlist)
 {
+  ListBase folderlistn = {NULL};
 
-  if (folderlist) {
-    ListBase *folderlistn = MEM_callocN(sizeof(*folderlistn), __func__);
-    FolderList *folder;
+  BLI_duplicatelist(&folderlistn, folderlist);
+
+  for (FolderList *folder = folderlistn.first; folder; folder = folder->next) {
+    folder->foldername = MEM_dupallocN(folder->foldername);
+  }
+  return folderlistn;
+}
 
-    BLI_duplicatelist(folderlistn, folderlist);
+/* ----------------- Folder-History (wraps/owns file list above) -------------- */
 
-    for (folder = folderlistn->first; folder; folder = folder->next) {
-      folder->foldername = MEM_dupallocN(folder->foldername);
+static FileFolderHistory *folder_history_find(const SpaceFile *sfile, eFileBrowse_Mode browse_mode)
+{
+  LISTBASE_FOREACH (FileFolderHistory *, history, &sfile->folder_histories) {
+    if (history->browse_mode == browse_mode) {
+      return history;
     }
-    return folderlistn;
   }
+
   return NULL;
 }
 
+void folder_history_list_ensure_for_active_browse_mode(SpaceFile *sfile)
+{
+  FileFolderHistory *history = folder_history_find(sfile, sfile->browse_mode);
+
+  if (!history) {
+    history = MEM_callocN(sizeof(*history), __func__);
+    history->browse_mode = sfile->browse_mode;
+    BLI_addtail(&sfile->folder_histories, history);
+  }
+
+  sfile->folders_next = &history->folders_next;
+  sfile->folders_prev = &history->folders_prev;
+}
+
+static void folder_history_entry_free(SpaceFile *sfile, FileFolderHistory *history)
+{
+  if (sfile->folders_prev == &history->folders_prev) {
+    sfile->folders_prev = NULL;
+  }
+  if (sfile->folders_next == &history->folders_next) {
+    sfile->folders_next = NULL;
+  }
+  folderlist_free(&history->folders_prev);
+  folderlist_free(&history->folders_next);
+  BLI_freelinkN(&sfile->folder_histories, history);
+}
+
+void folder_history_list_free(SpaceFile *sfile)
+{
+  LISTBASE_FOREACH_MUTABLE (FileFolderHistory *, history, &sfile->folder_histories) {
+    folder_history_entry_free(sfile, history);
+  }
+}
+
+ListBase folder_history_list_duplicate(ListBase *listbase)
+{
+  ListBase histories = {NULL};
+
+  LISTBASE_FOREACH (FileFolderHistory *, history, listbase) {
+    FileFolderHistory *history_new = MEM_dupallocN(history);
+    history_new->folders_prev = folderlist_duplicate(&history->folders_prev);
+    history_new->folders_next = folderlist_duplicate(&history->folders_next);
+    BLI_addtail(&histories, history_new);
+  }
+
+  return histories;
+}
+
 /* ------------------FILELIST------------------------ */
 
 typedef struct FileListInternEntry {
@@ -216,6 +276,24 @@ typedef struct FileListInternEntry {
   /** not strictly needed, but used during sorting, avoids to have to recompute it there... */
   char *name;
 
+  /**
+   * This is data from the current main, represented by this file. It's crucial that this is
+   * updated correctly on undo, redo and file reading (without UI). The space is responsible to
+   * take care of that.
+   */
+  struct {
+    /** When showing local IDs (FILE_MAIN, FILE_MAIN_ASSET), the ID this file entry represents. */
+    ID *id;
+
+    /* For the few file types that have the preview already in memory. For others, there's delayed
+     * preview reading from disk. Non-owning pointer. */
+    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;
+
   /** Defined in BLI_fileops.h */
   eFileAttributes attributes;
   BLI_stat_t st;
@@ -267,7 +345,11 @@ typedef struct FileListEntryPreview {
   char path[FILE_MAX];
   uint flags;
   int index;
-  ImBuf *img;
+  /* Some file types load the memory from runtime data, not from disk. We just wait until it's done
+   * generating (BKE_previewimg_is_finished()). */
+  PreviewImage *in_memory_preview;
+
+  int icon_id;
 } FileListEntryPreview;
 
 /* Dummy wrapper around FileListEntryPreview to ensure we do not access freed memory when freeing
@@ -290,11 +372,16 @@ enum {
   FLF_HIDE_DOT = 1 << 1,
   FLF_HIDE_PARENT = 1 << 2,
   FLF_HIDE_LIB_DIR = 1 << 3,
+  FLF_ASSETS_ONLY = 1 << 4,
 };
 
 typedef struct FileList {
   FileDirEntryArr filelist;
 
+  eFileSelectType type;
+  /* The library this list was created for. Stored here so we know when to re-read. */
+  FileSelectAssetLibraryUID *asset_library;
+
   short flags;
 
   short sort;
@@ -324,10 +411,13 @@ typedef struct FileList {
   bool (*checkdirf)(struct FileList *, char *, const bool);
 
   /* Fill filelist (to be called by read job). */
-  void (*read_jobf)(struct FileList *, const char *, short *, short *, float *, ThreadMutex *);
+  void (*read_jobf)(
+      Main *, struct FileList *, const char *, short *, short *, float *, ThreadMutex *);
 
   /* Filter an entry of current filelist. */
   bool (*filterf)(struct FileListInternEntry *, const char *, FileListFilter *);
+
+  short tags; /* FileListTags */
 } FileList;
 
 /* FileList.flags */
@@ -340,6 +430,14 @@ enum {
   FL_SORT_INVERT = 1 << 5,
 };
 
+/* FileList.tags */
+enum FileListTags {
+  /** The file list has references to main data (IDs) and needs special care. */
+  FILELIST_TAGS_USES_MAIN_DATA = (1 << 0),
+  /** The file list type is not thread-safe. */
+  FILELIST_TAGS_NO_THREADS = (1 << 2),
+};
+
 #define SPECIAL_IMG_SIZE 256
 #define SPECIAL_IMG_ROWS 1
 #define SPECIAL_IMG_COLS 7
@@ -357,24 +455,34 @@ enum {
 
 static ImBuf *gSpecialFileImages[SPECIAL_IMG_MAX];
 
-static void filelist_readjob_main(FileList *filelist,
+static void filelist_readjob_main(Main *current_main,
+                                  FileList *filelist,
                                   const char *main_name,
                                   short *stop,
                                   short *do_update,
                                   float *progress,
                                   ThreadMutex *lock);
-static void filelist_readjob_lib(FileList *filelist,
+static void filelist_readjob_lib(Main *current_main,
+                                 FileList *filelist,
                                  const char *main_name,
                                  short *stop,
                                  short *do_update,
                                  float *progress,
                                  ThreadMutex *lock);
-static void filelist_readjob_dir(FileList *filelist,
+static void filelist_readjob_dir(Main *current_main,
+                                 FileList *filelist,
                                  const char *main_name,
                                  short *stop,
                                  short *do_update,
                                  float *progress,
                                  ThreadMutex *lock);
+static void filelist_readjob_main_assets(Main *current_main,
+                                         FileList *filelist,
+                                         const char *main_name,
+                                         short *stop,
+                                         short *do_update,
+                                         float *progress,
+                                         ThreadMutex *lock);
 
 /* helper, could probably go in BKE actually? */
 static int groupname_to_code(const char *group);
@@ -694,6 +802,11 @@ static bool is_filtered_hidden(const char *filename,
     return true;
   }
 #endif
+  /* For data-blocks (but not the group directories), check the asset-only filter. */
+  if (!(file->typeflag & FILE_TYPE_DIR) && (file->typeflag & FILE_TYPE_BLENDERLIB) &&
+      (filter->flags & FLF_ASSETS_ONLY) && !(file->typeflag & FILE_TYPE_ASSET)) {
+    return true;
+  }
 
   return false;
 }
@@ -737,51 +850,61 @@ static bool is_filtered_file(FileListInternEntry *file,
   return is_filtered;
 }
 
-static bool is_filtered_lib(FileListInternEntry *file, const char *root, FileListFilter *filter)
+static bool is_filtered_id_file(const FileListInternEntry *file,
+                                const char *id_group,
+                                const char *name,
+                                const FileListFilter *filter)
 {
-  bool is_filtered;
-  char path[FILE_MAX_LIBEXTRA], dir[FILE_MAX_LIBEXTRA], *group, *name;
-
-  BLI_join_dirfile(path, sizeof(path), root, file->relpath);
-
-  if (BLO_library_path_explode(path, dir, &group, &name)) {
-    is_filtered = !is_filtered_hidden(file->relpath, filter, file);
-    if (is_filtered && !FILENAME_IS_CURRPAR(file->relpath)) {
-      /* We only check for types if some type are enabled in filtering. */
-      if ((filter->filter || filter->filter_id) && (filter->flags & FLF_DO_FILTER)) {
-        if (file->typeflag & FILE_TYPE_DIR) {
-          if (file->typeflag &
-              (FILE_TYPE_BLENDERLIB | FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) {
-            if (!(filter->filter & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP))) {
-              is_filtered = false;
-            }
-          }
-          else {
-            if (!(filter->filter & FILE_TYPE_FOLDER)) {
-              is_filtered = false;
-            }
+  bool is_filtered = !is_filtered_hidden(file->relpath, filter, file);
+  if (is_filtered && !FILENAME_IS_CURRPAR(file->relpath)) {
+    /* We only check for types if some type are enabled in filtering. */
+    if ((filter->filter || filter->filter_id) && (filter->flags & FLF_DO_FILTER)) {
+      if (file->typeflag & FILE_TYPE_DIR) {
+        if (file->typeflag &
+            (FILE_TYPE_BLENDERLIB | FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) {
+          if (!(filter->filter & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP))) {
+            is_filtered = false;
           }
         }
-        if (is_filtered && group) {
-          if (!name && (filter->flags & FLF_HIDE_LIB_DIR)) {
+        else {
+          if (!(filter->filter & FILE_TYPE_FOLDER)) {
             is_filtered = false;
           }
-          else {
-            uint64_t filter_id = groupname_to_filter_id(group);
-            if (!(filter_id & filter->filter_id)) {
-              is_filtered = false;
-            }
-          }
         }
       }
-      /* If there's a filter string, apply it as filter even if FLF_DO_FILTER is not set. */
-      if (is_filtered && (filter->filter_search[0] != '\0')) {
-        if (fnmatch(filter->filter_search, file->relpath, FNM_CASEFOLD) != 0) {
+      if (is_filtered && id_group) {
+        if (!name && (filter->flags & FLF_HIDE_LIB_DIR)) {
           is_filtered = false;
         }
+        else {
+          uint64_t filter_id = groupname_to_filter_id(id_group);
+          if (!(filter_id & filter->filter_id)) {
+            is_filtered = false;
+          }
+        }
+      }
+    }
+    /* If there's a filter string, apply it as filter even if FLF_DO_FILTER is not set. */
+    if (is_filtered && (filter->filter_search[0] != '\0')) {
+      if (fnmatch(filter->filter_search, file->relpath, FNM_CASEFOLD) != 0) {
+        is_filtered = false;
       }
     }
   }
+
+  return is_filtered;
+}
+
+static bool is_filtered_lib(FileListInternEntry *file, const char *root, FileListFilter *filter)
+{
+  bool is_filtered;
+  char path[FILE_MAX_LIBEXTRA], dir[FILE_MAX_LIBEXTRA], *group, *name;
+
+  BLI_join_dirfile(path, sizeof(path), root, file->relpath);
+
+  if (BLO_library_path_explode(path, dir, &group, &name)) {
+    is_filtered = is_filtered_id_file(file, group, name, filter);
+  }
   else {
     is_filtered = is_filtered_file(file, root, filter);
   }
@@ -796,6 +919,14 @@ static bool is_filtered_main(FileListInternEntry *file,
   return !is_filtered_hidden(file->relpath, filter, file);
 }
 
+static bool is_filtered_main_assets(FileListInternEntry *file,
+                                    const char *UNUSED(dir),
+                                    FileListFilter *filter)
+{
+  /* "Filtered" means *not* being filtered out... So return true if the file should be visible. */
+  return is_filtered_id_file(file, file->relpath, file->name, filter);
+}
+
 static void filelist_filter_clear(FileList *filelist)
 {
   filelist->flags |= FL_NEED_FILTERING;
@@ -807,7 +938,7 @@ void filelist_filter(FileList *filelist)
   const int num_files = filelist->filelist.nbr_entries;
   FileListInternEntry **filtered_tmp, *file;
 
-  if (filelist->filelist.nbr_entries == 0) {
+  if (ELEM(filelist->filelist.nbr_entries, FILEDIR_NBR_ENTRIES_UNSET, 0)) {
     return;
   }
 
@@ -858,6 +989,7 @@ void filelist_setfilter_options(FileList *filelist,
                                 const bool hide_parent,
                                 const uint64_t filter,
                                 const uint64_t filter_id,
+                                const bool filter_assets_only,
                                 const char *filter_glob,
                                 const char *filter_search)
 {
@@ -875,6 +1007,10 @@ void filelist_setfilter_options(FileList *filelist,
     filelist->filter_data.flags ^= FLF_HIDE_PARENT;
     update = true;
   }
+  if (((filelist->filter_data.flags & FLF_ASSETS_ONLY) != 0) != (filter_assets_only != 0)) {
+    filelist->filter_data.flags ^= FLF_ASSETS_ONLY;
+    update = true;
+  }
   if (filelist->filter_data.filter != filter) {
     filelist->filter_data.filter = filter;
     update = true;
@@ -903,6 +1039,50 @@ void filelist_setfilter_options(FileList *filelist,
   }
 }
 
+/**
+ * Checks two libraries for equality.
+ * \return True if the libraries match.
+ */
+static bool filelist_compare_asset_libraries(const FileSelectAssetLibraryUID *library_a,
+                                             const FileSelectAssetLibraryUID *library_b)
+{
+  if (library_a->type != library_b->type) {
+    return false;
+  }
+  if (library_a->type == FILE_ASSET_LIBRARY_CUSTOM) {
+    return STREQ(library_a->custom_library_identifier, library_b->custom_library_identifier);
+  }
+
+  return true;
+}
+
+/**
+ * \param asset_library: May be NULL to unset the library.
+ */
+void filelist_setlibrary(FileList *filelist, const FileSelectAssetLibraryUID *asset_library)
+{
+  /* Unset if needed. */
+  if (!asset_library) {
+    if (filelist->asset_library) {
+      MEM_SAFE_FREE(filelist->asset_library);
+      filelist->flags |= FL_FORCE_RESET;
+    }
+    return;
+  }
+
+  if (!filelist->asset_library) {
+    filelist->asset_library = MEM_mallocN(sizeof(*filelist->asset_library),
+                                          "filelist asset library");
+    *filelist->asset_library = *asset_library;
+
+    filelist->flags |= FL_FORCE_RESET;
+  }
+  else if (!filelist_compare_asset_libraries(filelist->asset_library, asset_library)) {
+    *filelist->asset_library = *asset_library;
+    filelist->flags |= FL_FORCE_RESET;
+  }
+}
+
 /* ********** Icon/image helpers ********** */
 
 void filelist_init_icons(void)
@@ -960,7 +1140,12 @@ ImBuf *filelist_getimage(struct FileList *filelist, const int index)
 {
   FileDirEntry *file = filelist_geticon_get_file(filelist, index);
 
-  return file->image;
+  return file->preview_icon_id ? BKE_icon_imbuf_get_buffer(file->preview_icon_id) : NULL;
+}
+
+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)
@@ -993,7 +1178,7 @@ static int filelist_geticon_ex(FileDirEntry *file,
                                const bool is_main,
                                const bool ignore_libdir)
 {
-  const int typeflag = file->typeflag;
+  const eFileSel_File_Types typeflag = file->typeflag;
 
   if ((typeflag & FILE_TYPE_DIR) &&
       !(ignore_libdir && (typeflag & (FILE_TYPE_BLENDERLIB | FILE_TYPE_BLENDER)))) {
@@ -1160,6 +1345,14 @@ static bool filelist_checkdir_main(struct FileList *filelist, char *r_dir, const
   return filelist_checkdir_lib(filelist, r_dir, do_change);
 }
 
+static bool filelist_checkdir_main_assets(struct FileList *UNUSED(filelist),
+                                          char *UNUSED(r_dir),
+                                          const bool UNUSED(do_change))
+{
+  /* Main is always valid. */
+  return true;
+}
+
 static void filelist_entry_clear(FileDirEntry *entry)
 {
   if (entry->name) {
@@ -1174,8 +1367,9 @@ static void filelist_entry_clear(FileDirEntry *entry)
   if (entry->redirection_path) {
     MEM_freeN(entry->redirection_path);
   }
-  if (entry->image) {
-    IMB_freeImBuf(entry->image);
+  if (entry->preview_icon_id) {
+    BKE_icon_delete(entry->preview_icon_id);
+    entry->preview_icon_id = 0;
   }
   /* For now, consider FileDirEntryRevision::poin as not owned here,
    * so no need to do anything about it */
@@ -1232,8 +1426,8 @@ static void filelist_direntryarr_free(FileDirEntryArr *array)
 #else
   BLI_assert(BLI_listbase_is_empty(&array->entries));
 #endif
-  array->nbr_entries = 0;
-  array->nbr_entries_filtered = -1;
+  array->nbr_entries = FILEDIR_NBR_ENTRIES_UNSET;
+  array->nbr_entries_filtered = FILEDIR_NBR_ENTRIES_UNSET;
   array->entry_idx_start = -1;
   array->entry_idx_end = -1;
 }
@@ -1249,6 +1443,10 @@ static void filelist_intern_entry_free(FileListInternEntry *entry)
   if (entry->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(entry);
 }
 
@@ -1272,37 +1470,52 @@ static void filelist_cache_preview_runf(TaskPool *__restrict pool, void *taskdat
   FileListEntryPreview *preview = preview_taskdata->preview;
 
   ThumbSource source = 0;
+  bool done = false;
 
   //  printf("%s: Start (%d)...\n", __func__, threadid);
 
-  //  printf("%s: %d - %s - %p\n", __func__, preview->index, preview->path, preview->img);
-  BLI_assert(preview->flags &
-             (FILE_TYPE_IMAGE | FILE_TYPE_MOVIE | FILE_TYPE_FTFONT | FILE_TYPE_BLENDER |
-              FILE_TYPE_BLENDER_BACKUP | FILE_TYPE_BLENDERLIB));
-
-  if (preview->flags & FILE_TYPE_IMAGE) {
-    source = THB_SOURCE_IMAGE;
-  }
-  else if (preview->flags &
-           (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP | FILE_TYPE_BLENDERLIB)) {
-    source = THB_SOURCE_BLEND;
-  }
-  else if (preview->flags & FILE_TYPE_MOVIE) {
-    source = THB_SOURCE_MOVIE;
-  }
-  else if (preview->flags & FILE_TYPE_FTFONT) {
-    source = THB_SOURCE_FONT;
+  if (preview->in_memory_preview) {
+    if (BKE_previewimg_is_finished(preview->in_memory_preview, ICON_SIZE_PREVIEW)) {
+      ImBuf *imbuf = BKE_previewimg_to_imbuf(preview->in_memory_preview, ICON_SIZE_PREVIEW);
+      preview->icon_id = BKE_icon_imbuf_create(imbuf);
+      done = true;
+    }
   }
+  else {
+    //  printf("%s: %d - %s - %p\n", __func__, preview->index, preview->path, preview->img);
+    BLI_assert(preview->flags &
+               (FILE_TYPE_IMAGE | FILE_TYPE_MOVIE | FILE_TYPE_FTFONT | FILE_TYPE_BLENDER |
+                FILE_TYPE_BLENDER_BACKUP | FILE_TYPE_BLENDERLIB));
 
-  IMB_thumb_path_lock(preview->path);
-  /* Always generate biggest preview size for now, it's simpler and avoids having to re-generate in
-   * case user switch to a bigger preview size. */
-  preview->img = IMB_thumb_manage(preview->path, THB_LARGE, source);
-  IMB_thumb_path_unlock(preview->path);
+    if (preview->flags & FILE_TYPE_IMAGE) {
+      source = THB_SOURCE_IMAGE;
+    }
+    else if (preview->flags &
+             (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP | FILE_TYPE_BLENDERLIB)) {
+      source = THB_SOURCE_BLEND;
+    }
+    else if (preview->flags & FILE_TYPE_MOVIE) {
+      source = THB_SOURCE_MOVIE;
+    }
+    else if (preview->flags & FILE_TYPE_FTFONT) {
+      source = THB_SOURCE_FONT;
+    }
+
+    IMB_thumb_path_lock(preview->path);
+    /* Always generate biggest preview size for now, it's simpler and avoids having to re-generate
+     * in case user switch to a bigger preview size. */
+    ImBuf *imbuf = IMB_thumb_manage(preview->path, THB_LARGE, source);
+    IMB_thumb_path_unlock(preview->path);
+    preview->icon_id = BKE_icon_imbuf_create(imbuf);
 
-  /* 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);
+    done = true;
+  }
+
+  if (done) {
+    /* 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);
+  }
 
   //  printf("%s: End (%d)...\n", __func__, threadid);
 }
@@ -1315,8 +1528,8 @@ static void filelist_cache_preview_freef(TaskPool *__restrict UNUSED(pool), void
   /* preview_taskdata->preview is atomically set to NULL once preview has been processed and sent
    * to previews_done queue. */
   if (preview != NULL) {
-    if (preview->img) {
-      IMB_freeImBuf(preview->img);
+    if (preview->icon_id) {
+      BKE_icon_delete(preview->icon_id);
     }
     MEM_freeN(preview);
   }
@@ -1342,8 +1555,8 @@ static void filelist_cache_previews_clear(FileListEntryCache *cache)
     while ((preview = BLI_thread_queue_pop_timeout(cache->previews_done, 0))) {
       // printf("%s: DONE %d - %s - %p\n", __func__, preview->index, preview->path,
       // preview->img);
-      if (preview->img) {
-        IMB_freeImBuf(preview->img);
+      if (preview->icon_id) {
+        BKE_icon_delete(preview->icon_id);
       }
       MEM_freeN(preview);
     }
@@ -1374,10 +1587,11 @@ static void filelist_cache_previews_push(FileList *filelist, FileDirEntry *entry
 
   BLI_assert(cache->flags & FLC_PREVIEWS_ACTIVE);
 
-  if (!entry->image && !(entry->flags & FILE_ENTRY_INVALID_PREVIEW) &&
+  if (!entry->preview_icon_id && !(entry->flags & FILE_ENTRY_INVALID_PREVIEW) &&
       (entry->typeflag & (FILE_TYPE_IMAGE | FILE_TYPE_MOVIE | FILE_TYPE_FTFONT |
                           FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP | FILE_TYPE_BLENDERLIB))) {
     FileListEntryPreview *preview = MEM_mallocN(sizeof(*preview), __func__);
+    FileListInternEntry *intern_entry = filelist->filelist_intern.filtered[index];
 
     if (entry->redirection_path) {
       BLI_strncpy(preview->path, entry->redirection_path, FILE_MAXDIR);
@@ -1389,7 +1603,8 @@ static void filelist_cache_previews_push(FileList *filelist, FileDirEntry *entry
 
     preview->index = index;
     preview->flags = entry->typeflag;
-    preview->img = NULL;
+    preview->in_memory_preview = intern_entry->local_data.preview_image;
+    preview->icon_id = 0;
     //      printf("%s: %d - %s - %p\n", __func__, preview->index, preview->path, preview->img);
 
     filelist_cache_preview_ensure_running(cache);
@@ -1497,25 +1712,45 @@ FileList *filelist_new(short type)
 
   p->selection_state = BLI_ghash_new(
       BLI_ghashutil_uinthash_v4_p, BLI_ghashutil_uinthash_v4_cmp, __func__);
+  p->filelist.nbr_entries = FILEDIR_NBR_ENTRIES_UNSET;
+  filelist_settype(p, type);
 
-  switch (type) {
+  return p;
+}
+
+void filelist_settype(FileList *filelist, short type)
+{
+  if (filelist->type == type) {
+    return;
+  }
+
+  filelist->type = type;
+  filelist->tags = 0;
+  switch (filelist->type) {
     case FILE_MAIN:
-      p->checkdirf = filelist_checkdir_main;
-      p->read_jobf = filelist_readjob_main;
-      p->filterf = is_filtered_main;
+      filelist->checkdirf = filelist_checkdir_main;
+      filelist->read_jobf = filelist_readjob_main;
+      filelist->filterf = is_filtered_main;
       break;
     case FILE_LOADLIB:
-      p->checkdirf = filelist_checkdir_lib;
-      p->read_jobf = filelist_readjob_lib;
-      p->filterf = is_filtered_lib;
+      filelist->checkdirf = filelist_checkdir_lib;
+      filelist->read_jobf = filelist_readjob_lib;
+      filelist->filterf = is_filtered_lib;
+      break;
+    case FILE_MAIN_ASSET:
+      filelist->checkdirf = filelist_checkdir_main_assets;
+      filelist->read_jobf = filelist_readjob_main_assets;
+      filelist->filterf = is_filtered_main_assets;
+      filelist->tags |= FILELIST_TAGS_USES_MAIN_DATA | FILELIST_TAGS_NO_THREADS;
       break;
     default:
-      p->checkdirf = filelist_checkdir_dir;
-      p->read_jobf = filelist_readjob_dir;
-      p->filterf = is_filtered_file;
+      filelist->checkdirf = filelist_checkdir_dir;
+      filelist->read_jobf = filelist_readjob_dir;
+      filelist->filterf = is_filtered_file;
       break;
   }
-  return p;
+
+  filelist->flags |= FL_FORCE_RESET;
 }
 
 void filelist_clear_ex(struct FileList *filelist, const bool do_cache, const bool do_selection)
@@ -1560,6 +1795,8 @@ void filelist_free(struct FileList *filelist)
     filelist->selection_state = NULL;
   }
 
+  MEM_SAFE_FREE(filelist->asset_library);
+
   memset(&filelist->filter_data, 0, sizeof(filelist->filter_data));
 
   filelist->flags &= ~(FL_NEED_SORTING | FL_NEED_FILTERING);
@@ -1580,7 +1817,7 @@ BlendHandle *filelist_lib(struct FileList *filelist)
 
 static const char *fileentry_uiname(const char *root,
                                     const char *relpath,
-                                    const int typeflag,
+                                    const eFileSel_File_Types typeflag,
                                     char *buff)
 {
   char *name = NULL;
@@ -1624,11 +1861,12 @@ bool filelist_is_dir(struct FileList *filelist, const char *path)
  */
 void filelist_setdir(struct FileList *filelist, char *r_dir)
 {
+  const bool allow_invalid = filelist->asset_library != NULL;
   BLI_assert(strlen(r_dir) < FILE_MAX_LIBEXTRA);
 
   BLI_path_normalize_dir(BKE_main_blendfile_path_from_global(), r_dir);
-  const bool is_valid_path = filelist->checkdirf(filelist, r_dir, true);
-  BLI_assert(is_valid_path);
+  const bool is_valid_path = filelist->checkdirf(filelist, r_dir, !allow_invalid);
+  BLI_assert(is_valid_path || allow_invalid);
   UNUSED_VARS_NDEBUG(is_valid_path);
 
   if (!STREQ(filelist->filelist.root, r_dir)) {
@@ -1645,11 +1883,16 @@ void filelist_setrecursion(struct FileList *filelist, const int recursion_level)
   }
 }
 
-bool filelist_force_reset(struct FileList *filelist)
+bool filelist_needs_force_reset(FileList *filelist)
 {
   return (filelist->flags & FL_FORCE_RESET) != 0;
 }
 
+void filelist_tag_force_reset(FileList *filelist)
+{
+  filelist->flags |= FL_FORCE_RESET;
+}
+
 bool filelist_is_ready(struct FileList *filelist)
 {
   return (filelist->flags & FL_IS_READY) != 0;
@@ -1660,6 +1903,11 @@ bool filelist_pending(struct FileList *filelist)
   return (filelist->flags & FL_IS_PENDING) != 0;
 }
 
+bool filelist_needs_reset_on_main_changes(const FileList *filelist)
+{
+  return (filelist->tags & FILELIST_TAGS_USES_MAIN_DATA) != 0;
+}
+
 /**
  * Limited version of full update done by space_file's file_refresh(),
  * to be used by operators and such.
@@ -1668,7 +1916,7 @@ bool filelist_pending(struct FileList *filelist)
  */
 int filelist_files_ensure(FileList *filelist)
 {
-  if (!filelist_force_reset(filelist) || !filelist_empty(filelist)) {
+  if (!filelist_needs_force_reset(filelist) || !filelist_needs_reading(filelist)) {
     filelist_sort(filelist);
     filelist_filter(filelist);
   }
@@ -1701,6 +1949,17 @@ static FileDirEntry *filelist_file_create_entry(FileList *filelist, const int in
   if (entry->redirection_path) {
     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 : NULL;
+  if (ret->id && (ret->asset_data == NULL)) {
+    ret->asset_data = ret->id->asset_data;
+  }
+  /* 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)) {
+    ImBuf *ibuf = BKE_previewimg_to_imbuf(entry->local_data.preview_image, ICON_SIZE_PREVIEW);
+    ret->preview_icon_id = BKE_icon_imbuf_create(ibuf);
+  }
   BLI_addtail(&cache->cached_entries, ret);
   return ret;
 }
@@ -1770,7 +2029,7 @@ int filelist_file_findpath(struct FileList *filelist, const char *filename)
 {
   int fidx = -1;
 
-  if (filelist->filelist.nbr_entries_filtered < 0) {
+  if (filelist->filelist.nbr_entries_filtered == FILEDIR_NBR_ENTRIES_UNSET) {
     return fidx;
   }
 
@@ -1788,9 +2047,17 @@ int filelist_file_findpath(struct FileList *filelist, const char *filename)
   return -1;
 }
 
+/**
+ * Get the ID a file represents (if any). For #FILE_MAIN, #FILE_MAIN_ASSET.
+ */
+ID *filelist_file_get_id(const FileDirEntry *file)
+{
+  return file->id;
+}
+
 FileDirEntry *filelist_entry_find_uuid(struct FileList *filelist, const int uuid[4])
 {
-  if (filelist->filelist.nbr_entries_filtered < 0) {
+  if (filelist->filelist.nbr_entries_filtered == FILEDIR_NBR_ENTRIES_UNSET) {
     return NULL;
   }
 
@@ -2147,15 +2414,17 @@ bool filelist_cache_previews_update(FileList *filelist)
 
     //      printf("%s: %d - %s - %p\n", __func__, preview->index, preview->path, preview->img);
 
-    if (preview->img) {
+    if (preview->icon_id) {
       /* Due to asynchronous process, a preview for a given image may be generated several times,
        * i.e. entry->image may already be set at this point. */
-      if (entry && !entry->image) {
-        entry->image = preview->img;
+      if (entry && !entry->preview_icon_id) {
+        /* Move ownership over icon. */
+        entry->preview_icon_id = preview->icon_id;
+        preview->icon_id = 0;
         changed = true;
       }
       else {
-        IMB_freeImBuf(preview->img);
+        BKE_icon_delete(preview->icon_id);
       }
     }
     else if (entry) {
@@ -2313,9 +2582,9 @@ int ED_file_extension_icon(const char *path)
   }
 }
 
-int filelist_empty(struct FileList *filelist)
+int filelist_needs_reading(struct FileList *filelist)
 {
-  return (filelist->filelist.nbr_entries == 0);
+  return (filelist->filelist.nbr_entries == FILEDIR_NBR_ENTRIES_UNSET);
 }
 
 uint filelist_entry_select_set(const FileList *filelist,
@@ -2564,8 +2833,8 @@ static int filelist_readjob_list_dir(const char *root,
 static int filelist_readjob_list_lib(const char *root, ListBase *entries, const bool skip_currpar)
 {
   FileListInternEntry *entry;
-  LinkNode *ln, *names;
-  int i, nnames, idcode = 0, nbr_entries = 0;
+  LinkNode *ln, *names = NULL, *datablock_infos = NULL;
+  int i, nitems, idcode = 0, nbr_entries = 0;
   char dir[FILE_MAX_LIBEXTRA], *group;
   bool ok;
 
@@ -2587,11 +2856,11 @@ static int filelist_readjob_list_lib(const char *root, ListBase *entries, const
    * and freed in filelist_entry_free. */
   if (group) {
     idcode = groupname_to_code(group);
-    names = BLO_blendhandle_get_datablock_names(libfiledata, idcode, &nnames);
+    datablock_infos = BLO_blendhandle_get_datablock_info(libfiledata, idcode, &nitems);
   }
   else {
     names = BLO_blendhandle_get_linkable_groups(libfiledata);
-    nnames = BLI_linklist_count(names);
+    nitems = BLI_linklist_count(names);
   }
 
   BLO_blendhandle_close(libfiledata);
@@ -2604,12 +2873,18 @@ static int filelist_readjob_list_lib(const char *root, ListBase *entries, const
     nbr_entries++;
   }
 
-  for (i = 0, ln = names; i < nnames; i++, ln = ln->next) {
-    const char *blockname = ln->link;
+  for (i = 0, ln = (datablock_infos ? datablock_infos : names); i < nitems; i++, ln = ln->next) {
+    struct BLODataBlockInfo *info = datablock_infos ? ln->link : NULL;
+    const char *blockname = info ? info->name : ln->link;
 
     entry = MEM_callocN(sizeof(*entry), __func__);
     entry->relpath = BLI_strdup(blockname);
     entry->typeflag |= FILE_TYPE_BLENDERLIB;
+    if (info && info->asset_data) {
+      entry->typeflag |= FILE_TYPE_ASSET;
+      /* Moves ownership! */
+      entry->imported_asset_data = info->asset_data;
+    }
     if (!(group && idcode)) {
       entry->typeflag |= FILE_TYPE_DIR;
       entry->blentype = groupname_to_code(blockname);
@@ -2621,7 +2896,7 @@ static int filelist_readjob_list_lib(const char *root, ListBase *entries, const
     nbr_entries++;
   }
 
-  BLI_linklist_freeN(names);
+  BLI_linklist_freeN(datablock_infos ? datablock_infos : names);
 
   return nbr_entries;
 }
@@ -2820,7 +3095,10 @@ static void filelist_readjob_do(const bool do_lib,
 
   //  BLI_assert(filelist->filtered == NULL);
   BLI_assert(BLI_listbase_is_empty(&filelist->filelist.entries) &&
-             (filelist->filelist.nbr_entries == 0));
+             (filelist->filelist.nbr_entries == FILEDIR_NBR_ENTRIES_UNSET));
+
+  /* A valid, but empty directory from now. */
+  filelist->filelist.nbr_entries = 0;
 
   todo_dirs = BLI_stack_new(sizeof(*td_dir), __func__);
   td_dir = BLI_stack_push_r(todo_dirs);
@@ -2932,7 +3210,8 @@ static void filelist_readjob_do(const bool do_lib,
   BLI_stack_free(todo_dirs);
 }
 
-static void filelist_readjob_dir(FileList *filelist,
+static void filelist_readjob_dir(Main *UNUSED(current_main),
+                                 FileList *filelist,
                                  const char *main_name,
                                  short *stop,
                                  short *do_update,
@@ -2942,7 +3221,8 @@ static void filelist_readjob_dir(FileList *filelist,
   filelist_readjob_do(false, filelist, main_name, stop, do_update, progress, lock);
 }
 
-static void filelist_readjob_lib(FileList *filelist,
+static void filelist_readjob_lib(Main *UNUSED(current_main),
+                                 FileList *filelist,
                                  const char *main_name,
                                  short *stop,
                                  short *do_update,
@@ -2952,7 +3232,8 @@ static void filelist_readjob_lib(FileList *filelist,
   filelist_readjob_do(true, filelist, main_name, stop, do_update, progress, lock);
 }
 
-static void filelist_readjob_main(FileList *filelist,
+static void filelist_readjob_main(Main *current_main,
+                                  FileList *filelist,
                                   const char *main_name,
                                   short *stop,
                                   short *do_update,
@@ -2960,12 +3241,67 @@ static void filelist_readjob_main(FileList *filelist,
                                   ThreadMutex *lock)
 {
   /* TODO! */
-  filelist_readjob_dir(filelist, main_name, stop, do_update, progress, lock);
+  filelist_readjob_dir(current_main, filelist, main_name, stop, do_update, progress, lock);
+}
+
+/**
+ * \warning Acts on main, so NOT thread-safe!
+ */
+static void filelist_readjob_main_assets(Main *current_main,
+                                         FileList *filelist,
+                                         const char *UNUSED(main_name),
+                                         short *UNUSED(stop),
+                                         short *do_update,
+                                         float *UNUSED(progress),
+                                         ThreadMutex *UNUSED(lock))
+{
+  BLI_assert(BLI_listbase_is_empty(&filelist->filelist.entries) &&
+             (filelist->filelist.nbr_entries == FILEDIR_NBR_ENTRIES_UNSET));
+
+  /* A valid, but empty directory from now. */
+  filelist->filelist.nbr_entries = 0;
+
+  FileListInternEntry *entry;
+  ListBase tmp_entries = {0};
+  ID *id_iter;
+  int nbr_entries = 0;
+
+  FOREACH_MAIN_ID_BEGIN (current_main, id_iter) {
+    if (!id_iter->asset_data) {
+      continue;
+    }
+
+    const char *id_code_name = BKE_idtype_idcode_to_name(GS(id_iter->name));
+
+    entry = MEM_callocN(sizeof(*entry), __func__);
+    entry->relpath = BLI_strdup(id_code_name);
+    entry->name = BLI_strdup(id_iter->name + 2);
+    entry->typeflag |= FILE_TYPE_BLENDERLIB | FILE_TYPE_ASSET;
+    entry->blentype = GS(id_iter->name);
+    *((uint32_t *)entry->uuid) = atomic_add_and_fetch_uint32(
+        (uint32_t *)filelist->filelist_intern.curr_uuid, 1);
+    entry->local_data.preview_image = BKE_asset_metadata_preview_get_from_id(id_iter->asset_data,
+                                                                             id_iter);
+    entry->local_data.id = id_iter;
+    nbr_entries++;
+    BLI_addtail(&tmp_entries, entry);
+  }
+  FOREACH_MAIN_ID_END;
+
+  if (nbr_entries) {
+    *do_update = true;
+
+    BLI_movelisttolist(&filelist->filelist.entries, &tmp_entries);
+    filelist->filelist.nbr_entries += nbr_entries;
+    filelist->filelist.nbr_entries_filtered = filelist->filelist.entry_idx_start =
+        filelist->filelist.entry_idx_end = -1;
+  }
 }
 
 typedef struct FileListReadJob {
   ThreadMutex lock;
   char main_name[FILE_MAX];
+  Main *current_main;
   struct FileList *filelist;
   /** XXX We may use a simpler struct here... just a linked list and root path? */
   struct FileList *tmp_filelist;
@@ -2985,7 +3321,7 @@ static void filelist_readjob_startjob(void *flrjv, short *stop, short *do_update
   flrj->tmp_filelist = MEM_dupallocN(flrj->filelist);
 
   BLI_listbase_clear(&flrj->tmp_filelist->filelist.entries);
-  flrj->tmp_filelist->filelist.nbr_entries = 0;
+  flrj->tmp_filelist->filelist.nbr_entries = FILEDIR_NBR_ENTRIES_UNSET;
 
   flrj->tmp_filelist->filelist_intern.filtered = NULL;
   BLI_listbase_clear(&flrj->tmp_filelist->filelist_intern.entries);
@@ -2996,11 +3332,17 @@ static void filelist_readjob_startjob(void *flrjv, short *stop, short *do_update
   flrj->tmp_filelist->libfiledata = NULL;
   memset(&flrj->tmp_filelist->filelist_cache, 0, sizeof(flrj->tmp_filelist->filelist_cache));
   flrj->tmp_filelist->selection_state = NULL;
+  flrj->tmp_filelist->asset_library = NULL;
 
   BLI_mutex_unlock(&flrj->lock);
 
-  flrj->tmp_filelist->read_jobf(
-      flrj->tmp_filelist, flrj->main_name, stop, do_update, progress, &flrj->lock);
+  flrj->tmp_filelist->read_jobf(flrj->current_main,
+                                flrj->tmp_filelist,
+                                flrj->main_name,
+                                stop,
+                                do_update,
+                                progress,
+                                &flrj->lock);
 }
 
 static void filelist_readjob_update(void *flrjv)
@@ -3015,7 +3357,7 @@ static void filelist_readjob_update(void *flrjv)
 
   BLI_mutex_lock(&flrj->lock);
 
-  if (flrj->tmp_filelist->filelist.nbr_entries) {
+  if (flrj->tmp_filelist->filelist.nbr_entries > 0) {
     /* We just move everything out of 'thread context' into final list. */
     new_nbr_entries = flrj->tmp_filelist->filelist.nbr_entries;
     BLI_movelisttolist(&new_entries, &flrj->tmp_filelist->filelist.entries);
@@ -3033,7 +3375,7 @@ static void filelist_readjob_update(void *flrjv)
 
   /* if no new_nbr_entries, this is NOP */
   BLI_movelisttolist(&fl_intern->entries, &new_entries);
-  flrj->filelist->filelist.nbr_entries = nbr_entries + new_nbr_entries;
+  flrj->filelist->filelist.nbr_entries = MAX2(nbr_entries, 0) + new_nbr_entries;
 }
 
 static void filelist_readjob_endjob(void *flrjv)
@@ -3074,30 +3416,51 @@ void filelist_readjob_start(FileList *filelist, const bContext *C)
   wmJob *wm_job;
   FileListReadJob *flrj;
 
+  if (!filelist_is_dir(filelist, filelist->filelist.root)) {
+    return;
+  }
+
   /* prepare job data */
   flrj = MEM_callocN(sizeof(*flrj), __func__);
   flrj->filelist = filelist;
+  flrj->current_main = bmain;
   BLI_strncpy(flrj->main_name, BKE_main_blendfile_path(bmain), sizeof(flrj->main_name));
 
   filelist->flags &= ~(FL_FORCE_RESET | FL_IS_READY);
   filelist->flags |= FL_IS_PENDING;
 
+  /* Init even for single threaded execution. Called functions use it. */
   BLI_mutex_init(&flrj->lock);
 
-  /* setup job */
-  wm_job = WM_jobs_get(CTX_wm_manager(C),
-                       CTX_wm_window(C),
-                       CTX_data_scene(C),
-                       "Listing Dirs...",
-                       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);
-  WM_jobs_callbacks(
-      wm_job, filelist_readjob_startjob, NULL, filelist_readjob_update, filelist_readjob_endjob);
-
-  /* start the job */
-  WM_jobs_start(CTX_wm_manager(C), wm_job);
+  if (filelist->tags & FILELIST_TAGS_NO_THREADS) {
+    short dummy_stop = false;
+    short dummy_do_update = false;
+    float dummy_progress = 0.0f;
+
+    /* Single threaded execution. Just directly call the callbacks. */
+    filelist_readjob_startjob(flrj, &dummy_stop, &dummy_do_update, &dummy_progress);
+    filelist_readjob_endjob(flrj);
+    filelist_readjob_free(flrj);
+
+    WM_event_add_notifier(C, NC_SPACE | ND_SPACE_FILE_LIST, NULL);
+    return;
+  }
+  else {
+    /* setup job */
+    wm_job = WM_jobs_get(CTX_wm_manager(C),
+                         CTX_wm_window(C),
+                         CTX_data_scene(C),
+                         "Listing Dirs...",
+                         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);
+    WM_jobs_callbacks(
+        wm_job, filelist_readjob_startjob, NULL, filelist_readjob_update, filelist_readjob_endjob);
+
+    /* start the job */
+    WM_jobs_start(CTX_wm_manager(C), wm_job);
+  }
 }
 
 void filelist_readjob_stop(wmWindowManager *wm, Scene *owner_scene)
diff --git a/source/blender/editors/space_file/filelist.h b/source/blender/editors/space_file/filelist.h
index 4b8cc052382..59bd5bb50d7 100644
--- a/source/blender/editors/space_file/filelist.h
+++ b/source/blender/editors/space_file/filelist.h
@@ -30,6 +30,7 @@ extern "C" {
 struct BlendHandle;
 struct FileList;
 struct FileSelection;
+struct FileSelectAssetLibraryUID;
 struct wmWindowManager;
 
 struct FileDirEntry;
@@ -46,14 +47,16 @@ typedef enum FileCheckType {
   CHECK_ALL = 3,
 } FileCheckType;
 
-struct ListBase *folderlist_new(void);
 void folderlist_free(struct ListBase *folderlist);
-struct ListBase *folderlist_duplicate(ListBase *folderlist);
 void folderlist_popdir(struct ListBase *folderlist, char *dir);
 void folderlist_pushdir(struct ListBase *folderlist, const char *dir);
 const char *folderlist_peeklastdir(struct ListBase *folderlist);
 int folderlist_clear_next(struct SpaceFile *sfile);
 
+void folder_history_list_ensure_for_active_browse_mode(struct SpaceFile *sfile);
+void folder_history_list_free(struct SpaceFile *sfile);
+struct ListBase folder_history_list_duplicate(struct ListBase *listbase);
+
 void filelist_setsorting(struct FileList *filelist, const short sort, bool invert_sort);
 void filelist_sort(struct FileList *filelist);
 
@@ -63,17 +66,22 @@ void filelist_setfilter_options(struct FileList *filelist,
                                 const bool hide_parent,
                                 const uint64_t filter,
                                 const uint64_t filter_id,
+                                const bool filter_assets_only,
                                 const char *filter_glob,
                                 const char *filter_search);
 void filelist_filter(struct FileList *filelist);
+void filelist_setlibrary(struct FileList *filelist,
+                         const struct FileSelectAssetLibraryUID *asset_library);
 
 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(struct FileList *filelist, const int index);
 int filelist_geticon(struct FileList *filelist, const int index, const bool is_main);
 
 struct FileList *filelist_new(short type);
+void filelist_settype(struct FileList *filelist, short type);
 void filelist_clear(struct FileList *filelist);
 void filelist_clear_ex(struct FileList *filelist, const bool do_cache, const bool do_selection);
 void filelist_free(struct FileList *filelist);
@@ -83,15 +91,18 @@ bool filelist_is_dir(struct FileList *filelist, const char *path);
 void filelist_setdir(struct FileList *filelist, char *r_dir);
 
 int filelist_files_ensure(struct FileList *filelist);
-int filelist_empty(struct FileList *filelist);
+int filelist_needs_reading(struct FileList *filelist);
 FileDirEntry *filelist_file(struct FileList *filelist, int index);
 int filelist_file_findpath(struct FileList *filelist, const char *file);
+struct ID *filelist_file_get_id(const struct FileDirEntry *file);
 FileDirEntry *filelist_entry_find_uuid(struct FileList *filelist, const int uuid[4]);
 void filelist_file_cache_slidingwindow_set(struct FileList *filelist, size_t window_size);
 bool filelist_file_cache_block(struct FileList *filelist, const int index);
 
-bool filelist_force_reset(struct FileList *filelist);
+bool filelist_needs_force_reset(struct FileList *filelist);
+void filelist_tag_force_reset(struct FileList *filelist);
 bool filelist_pending(struct FileList *filelist);
+bool filelist_needs_reset_on_main_changes(const struct FileList *filelist);
 bool filelist_is_ready(struct FileList *filelist);
 
 unsigned int filelist_entry_select_set(const struct FileList *filelist,
diff --git a/source/blender/editors/space_file/filesel.c b/source/blender/editors/space_file/filesel.c
index 6e933e53a8f..2c66bd39e0a 100644
--- a/source/blender/editors/space_file/filesel.c
+++ b/source/blender/editors/space_file/filesel.c
@@ -56,7 +56,9 @@
 
 #include "BKE_appdir.h"
 #include "BKE_context.h"
+#include "BKE_idtype.h"
 #include "BKE_main.h"
+#include "BKE_preferences.h"
 
 #include "BLF_api.h"
 
@@ -77,14 +79,66 @@
 
 #define VERTLIST_MAJORCOLUMN_WIDTH (25 * UI_UNIT_X)
 
-FileSelectParams *ED_fileselect_get_active_params(const SpaceFile *sfile)
+static void fileselect_initialize_params_common(SpaceFile *sfile, FileSelectParams *params)
 {
-  if (!sfile) {
-    /* Sometimes called in poll before space type was checked. */
-    return NULL;
+  const char *blendfile_path = BKE_main_blendfile_path_from_global();
+
+  /* operator has no setting for this */
+  params->active_file = -1;
+
+  if (!params->dir[0]) {
+    if (blendfile_path[0] != '\0') {
+      BLI_split_dir_part(blendfile_path, params->dir, sizeof(params->dir));
+    }
+    else {
+      const char *doc_path = BKE_appdir_folder_default();
+      if (doc_path) {
+        BLI_strncpy(params->dir, doc_path, sizeof(params->dir));
+      }
+    }
   }
 
-  return sfile->params;
+  folder_history_list_ensure_for_active_browse_mode(sfile);
+  folderlist_pushdir(sfile->folders_prev, params->dir);
+
+  /* Switching thumbnails needs to recalc layout T28809. */
+  if (sfile->layout) {
+    sfile->layout->dirty = true;
+  }
+}
+
+static void fileselect_ensure_updated_asset_params(SpaceFile *sfile)
+{
+  BLI_assert(sfile->browse_mode == FILE_BROWSE_MODE_ASSETS);
+  BLI_assert(sfile->op == NULL);
+
+  FileAssetSelectParams *asset_params = sfile->asset_params;
+
+  if (!asset_params) {
+    asset_params = sfile->asset_params = MEM_callocN(sizeof(*asset_params),
+                                                     "FileAssetSelectParams");
+    asset_params->base_params.details_flags = U_default.file_space_data.details_flags;
+    asset_params->asset_library.type = FILE_ASSET_LIBRARY_LOCAL;
+  }
+
+  FileSelectParams *base_params = &asset_params->base_params;
+  base_params->file[0] = '\0';
+  base_params->filter_glob[0] = '\0';
+  /* TODO this way of using filters to form categories is notably slower than specifying a
+   * "group" to read. That's because all types are read and filtering is applied afterwards. Would
+   * be nice if we could lazy-read individual groups. */
+  base_params->flag |= U_default.file_space_data.flag | FILE_ASSETS_ONLY | FILE_FILTER;
+  base_params->flag &= ~FILE_DIRSEL_ONLY;
+  base_params->filter |= FILE_TYPE_BLENDERLIB;
+  base_params->filter_id = FILTER_ID_OB | FILTER_ID_GR;
+  base_params->display = FILE_IMGDISPLAY;
+  base_params->sort = FILE_SORT_ALPHA;
+  base_params->recursion_level = 1;
+  /* 'SMALL' size by default. More reasonable since this is typically used as regular editor,
+   * space is more of an issue here. */
+  base_params->thumbnail_size = 96;
+
+  fileselect_initialize_params_common(sfile, base_params);
 }
 
 /**
@@ -92,6 +146,8 @@ FileSelectParams *ED_fileselect_get_active_params(const SpaceFile *sfile)
  *       the previously used settings to be used here rather than overriding them */
 static FileSelectParams *fileselect_ensure_updated_file_params(SpaceFile *sfile)
 {
+  BLI_assert(sfile->browse_mode == FILE_BROWSE_MODE_FILES);
+
   FileSelectParams *params;
   wmOperator *op = sfile->op;
 
@@ -297,42 +353,102 @@ static FileSelectParams *fileselect_ensure_updated_file_params(SpaceFile *sfile)
     params->filter_glob[0] = '\0';
   }
 
-  /* operator has no setting for this */
-  params->active_file = -1;
+  fileselect_initialize_params_common(sfile, params);
 
-  /* initialize the list with previous folders */
-  if (!sfile->folders_prev) {
-    sfile->folders_prev = folderlist_new();
-  }
+  return params;
+}
 
-  if (!params->dir[0]) {
-    if (blendfile_path[0] != '\0') {
-      BLI_split_dir_part(blendfile_path, params->dir, sizeof(params->dir));
-    }
-    else {
-      const char *doc_path = BKE_appdir_folder_default();
-      if (doc_path) {
-        BLI_strncpy(params->dir, doc_path, sizeof(params->dir));
+/**
+ * If needed, create and return the file select parameters for the active browse mode.
+ */
+FileSelectParams *ED_fileselect_ensure_active_params(SpaceFile *sfile)
+{
+  switch ((eFileBrowse_Mode)sfile->browse_mode) {
+    case FILE_BROWSE_MODE_FILES:
+      if (!sfile->params) {
+        fileselect_ensure_updated_file_params(sfile);
       }
-    }
+      return sfile->params;
+    case FILE_BROWSE_MODE_ASSETS:
+      if (!sfile->asset_params) {
+        fileselect_ensure_updated_asset_params(sfile);
+      }
+      return &sfile->asset_params->base_params;
   }
 
-  folderlist_pushdir(sfile->folders_prev, params->dir);
+  BLI_assert(!"Invalid browse mode set in file space.");
+  return NULL;
+}
 
-  /* Switching thumbnails needs to recalc layout T28809. */
-  if (sfile->layout) {
-    sfile->layout->dirty = true;
+/**
+ * Get the file select parameters for the active browse mode.
+ */
+FileSelectParams *ED_fileselect_get_active_params(const SpaceFile *sfile)
+{
+  if (!sfile) {
+    /* Sometimes called in poll before space type was checked. */
+    return NULL;
   }
 
-  return params;
+  switch ((eFileBrowse_Mode)sfile->browse_mode) {
+    case FILE_BROWSE_MODE_FILES:
+      return sfile->params;
+    case FILE_BROWSE_MODE_ASSETS:
+      return (FileSelectParams *)sfile->asset_params;
+  }
+
+  BLI_assert(!"Invalid browse mode set in file space.");
+  return NULL;
 }
 
-FileSelectParams *ED_fileselect_ensure_active_params(SpaceFile *sfile)
+FileSelectParams *ED_fileselect_get_file_params(const SpaceFile *sfile)
 {
-  if (!sfile->params) {
-    fileselect_ensure_updated_file_params(sfile);
+  return (sfile->browse_mode == FILE_BROWSE_MODE_FILES) ? sfile->params : NULL;
+}
+
+FileAssetSelectParams *ED_fileselect_get_asset_params(const SpaceFile *sfile)
+{
+  return (sfile->browse_mode == FILE_BROWSE_MODE_ASSETS) ? sfile->asset_params : NULL;
+}
+
+static void fileselect_refresh_asset_params(FileAssetSelectParams *asset_params)
+{
+  FileSelectAssetLibraryUID *library = &asset_params->asset_library;
+  FileSelectParams *base_params = &asset_params->base_params;
+  bUserAssetLibrary *user_library = NULL;
+
+  /* Ensure valid repo, or fall-back to local one. */
+  if (library->type == FILE_ASSET_LIBRARY_CUSTOM) {
+    user_library = BKE_preferences_asset_library_find_from_name(
+        &U, library->custom_library_identifier);
+    if (!user_library) {
+      library->type = FILE_ASSET_LIBRARY_LOCAL;
+    }
+  }
+
+  switch (library->type) {
+    case FILE_ASSET_LIBRARY_LOCAL:
+      base_params->dir[0] = '\0';
+      break;
+    case FILE_ASSET_LIBRARY_CUSTOM:
+      BLI_assert(user_library);
+      BLI_strncpy(base_params->dir, user_library->path, sizeof(base_params->dir));
+      break;
   }
-  return sfile->params;
+  base_params->type = (library->type == FILE_ASSET_LIBRARY_LOCAL) ? FILE_MAIN_ASSET : FILE_LOADLIB;
+}
+
+void fileselect_refresh_params(SpaceFile *sfile)
+{
+  FileAssetSelectParams *asset_params = ED_fileselect_get_asset_params(sfile);
+  if (asset_params) {
+    fileselect_refresh_asset_params(asset_params);
+  }
+}
+
+bool ED_fileselect_is_asset_browser(const SpaceFile *sfile)
+{
+  return (sfile->browse_mode == FILE_BROWSE_MODE_ASSETS);
 }
 
 /* The subset of FileSelectParams.flag items we store into preferences. Note that FILE_SORT_ALPHA
@@ -371,6 +487,8 @@ void ED_fileselect_set_params_from_userdef(SpaceFile *sfile)
   wmOperator *op = sfile->op;
   UserDef_FileSpaceData *sfile_udata = &U.file_space_data;
 
+  BLI_assert(sfile->browse_mode == FILE_BROWSE_MODE_FILES);
+
   FileSelectParams *params = fileselect_ensure_updated_file_params(sfile);
   if (!op) {
     return;
@@ -438,15 +556,6 @@ void ED_fileselect_params_to_userdef(SpaceFile *sfile,
   }
 }
 
-void ED_fileselect_reset_params(SpaceFile *sfile)
-{
-  FileSelectParams *params = ED_fileselect_get_active_params(sfile);
-  params->type = FILE_UNIX;
-  params->flag = 0;
-  params->title[0] = '\0';
-  params->active_file = -1;
-}
-
 /**
  * Sets FileSelectParams->file (name of selected file)
  */
@@ -1046,8 +1155,7 @@ void ED_fileselect_exit(wmWindowManager *wm, Scene *owner_scene, SpaceFile *sfil
     sfile->op = NULL;
   }
 
-  folderlist_free(sfile->folders_prev);
-  folderlist_free(sfile->folders_next);
+  folder_history_list_free(sfile);
 
   if (sfile->files) {
     ED_fileselect_clear(wm, owner_scene, sfile);
diff --git a/source/blender/editors/space_file/space_file.c b/source/blender/editors/space_file/space_file.c
index c72ca58abba..f1d72387791 100644
--- a/source/blender/editors/space_file/space_file.c
+++ b/source/blender/editors/space_file/space_file.c
@@ -35,6 +35,8 @@
 #include "BKE_screen.h"
 
 #include "RNA_access.h"
+#include "RNA_define.h"
+#include "RNA_enum_types.h"
 
 #include "WM_api.h"
 #include "WM_message.h"
@@ -149,22 +151,10 @@ static void file_free(SpaceLink *sl)
     sfile->files = NULL;
   }
 
-  if (sfile->folders_prev) {
-    folderlist_free(sfile->folders_prev);
-    MEM_freeN(sfile->folders_prev);
-    sfile->folders_prev = NULL;
-  }
-
-  if (sfile->folders_next) {
-    folderlist_free(sfile->folders_next);
-    MEM_freeN(sfile->folders_next);
-    sfile->folders_next = NULL;
-  }
+  folder_history_list_free(sfile);
 
-  if (sfile->params) {
-    MEM_freeN(sfile->params);
-    sfile->params = NULL;
-  }
+  MEM_SAFE_FREE(sfile->params);
+  MEM_SAFE_FREE(sfile->asset_params);
 
   if (sfile->layout) {
     MEM_freeN(sfile->layout);
@@ -205,19 +195,20 @@ static SpaceLink *file_duplicate(SpaceLink *sl)
   sfilen->previews_timer = NULL;
   sfilen->smoothscroll_timer = NULL;
 
+  FileSelectParams *active_params_old = ED_fileselect_get_active_params(sfileo);
+  if (active_params_old) {
+    sfilen->files = filelist_new(active_params_old->type);
+    filelist_setdir(sfilen->files, active_params_old->dir);
+  }
+
   if (sfileo->params) {
-    sfilen->files = filelist_new(sfileo->params->type);
     sfilen->params = MEM_dupallocN(sfileo->params);
-    filelist_setdir(sfilen->files, sfilen->params->dir);
   }
-
-  if (sfileo->folders_prev) {
-    sfilen->folders_prev = folderlist_duplicate(sfileo->folders_prev);
+  if (sfileo->asset_params) {
+    sfilen->asset_params = MEM_dupallocN(sfileo->asset_params);
   }
 
-  if (sfileo->folders_next) {
-    sfilen->folders_next = folderlist_duplicate(sfileo->folders_next);
-  }
+  sfilen->folder_histories = folder_history_list_duplicate(&sfileo->folder_histories);
 
   if (sfileo->layout) {
     sfilen->layout = MEM_dupallocN(sfileo->layout);
@@ -265,24 +256,42 @@ static void file_ensure_valid_region_state(bContext *C,
   }
 }
 
+/**
+ * Tag the space to recreate the file-list.
+ */
+static void file_tag_reset_list(ScrArea *area, SpaceFile *sfile)
+{
+  filelist_tag_force_reset(sfile->files);
+  ED_area_tag_refresh(area);
+}
+
 static void file_refresh(const bContext *C, ScrArea *area)
 {
   wmWindowManager *wm = CTX_wm_manager(C);
   wmWindow *win = CTX_wm_window(C);
   SpaceFile *sfile = CTX_wm_space_file(C);
   FileSelectParams *params = ED_fileselect_ensure_active_params(sfile);
+  FileAssetSelectParams *asset_params = ED_fileselect_get_asset_params(sfile);
   struct FSMenu *fsmenu = ED_fsmenu_get();
 
-  if (!sfile->folders_prev) {
-    sfile->folders_prev = folderlist_new();
+  fileselect_refresh_params(sfile);
+  folder_history_list_ensure_for_active_browse_mode(sfile);
+
+  if (sfile->files && (sfile->tags & FILE_TAG_REBUILD_MAIN_FILES) &&
+      filelist_needs_reset_on_main_changes(sfile->files)) {
+    filelist_tag_force_reset(sfile->files);
   }
+  sfile->tags &= ~FILE_TAG_REBUILD_MAIN_FILES;
+
   if (!sfile->files) {
     sfile->files = filelist_new(params->type);
     params->highlight_file = -1; /* added this so it opens nicer (ton) */
   }
+  filelist_settype(sfile->files, params->type);
   filelist_setdir(sfile->files, params->dir);
   filelist_setrecursion(sfile->files, params->recursion_level);
   filelist_setsorting(sfile->files, params->sort, params->flag & FILE_SORT_INVERT);
+  filelist_setlibrary(sfile->files, asset_params ? &asset_params->asset_library : NULL);
   filelist_setfilter_options(
       sfile->files,
       (params->flag & FILE_FILTER) != 0,
@@ -290,6 +299,7 @@ static void file_refresh(const bContext *C, ScrArea *area)
       true, /* Just always hide parent, prefer to not add an extra user option for this. */
       params->filter,
       params->filter_id,
+      (params->flag & FILE_ASSETS_ONLY) != 0,
       params->filter_glob,
       params->filter_search);
 
@@ -300,12 +310,12 @@ static void file_refresh(const bContext *C, ScrArea *area)
   sfile->bookmarknr = fsmenu_get_active_indices(fsmenu, FS_CATEGORY_BOOKMARKS, params->dir);
   sfile->recentnr = fsmenu_get_active_indices(fsmenu, FS_CATEGORY_RECENT, params->dir);
 
-  if (filelist_force_reset(sfile->files)) {
+  if (filelist_needs_force_reset(sfile->files)) {
     filelist_readjob_stop(wm, CTX_data_scene(C));
     filelist_clear(sfile->files);
   }
 
-  if (filelist_empty(sfile->files)) {
+  if (filelist_needs_reading(sfile->files)) {
     if (!filelist_pending(sfile->files)) {
       filelist_readjob_start(sfile->files, C);
     }
@@ -365,6 +375,14 @@ static void file_listener(wmWindow *UNUSED(win),
           break;
       }
       break;
+    case NC_ASSET: {
+      if (sfile->files && filelist_needs_reset_on_main_changes(sfile->files)) {
+        /* Full refresh of the file list if local asset data was changed. Refreshing this view is
+         * cheap and users expect this to be updated immediately. */
+        file_tag_reset_list(area, sfile);
+      }
+      break;
+    }
   }
 }
 
@@ -442,6 +460,22 @@ static void file_main_region_message_subscribe(const struct bContext *UNUSED(C),
   }
 }
 
+static bool file_main_region_needs_refresh_before_draw(SpaceFile *sfile)
+{
+  /* Needed, because filelist is not initialized on loading */
+  if (!sfile->files || filelist_needs_reading(sfile->files)) {
+    return true;
+  }
+
+  /* File reading tagged the space because main data changed that may require a filelist reset. */
+  if (filelist_needs_reset_on_main_changes(sfile->files) &&
+      (sfile->tags & FILE_TAG_REBUILD_MAIN_FILES)) {
+    return true;
+  }
+
+  return false;
+}
+
 static void file_main_region_draw(const bContext *C, ARegion *region)
 {
   /* draw entirely, view changes should be handled here */
@@ -450,8 +484,7 @@ static void file_main_region_draw(const bContext *C, ARegion *region)
 
   View2D *v2d = &region->v2d;
 
-  /* Needed, because filelist is not initialized on loading */
-  if (!sfile->files || filelist_empty(sfile->files)) {
+  if (file_main_region_needs_refresh_before_draw(sfile)) {
     file_refresh(C, NULL);
   }
 
@@ -681,6 +714,52 @@ static void file_dropboxes(void)
   WM_dropbox_add(lb, "FILE_OT_filepath_drop", filepath_drop_poll, filepath_drop_copy);
 }
 
+const char *file_context_dir[] = {"active_file", "active_id", NULL};
+
+static int /*eContextResult*/ file_context(const bContext *C,
+                                           const char *member,
+                                           bContextDataResult *result)
+{
+  bScreen *screen = CTX_wm_screen(C);
+  SpaceFile *sfile = CTX_wm_space_file(C);
+  FileSelectParams *params = ED_fileselect_get_active_params(sfile);
+
+  BLI_assert(!ED_area_is_global(CTX_wm_area(C)));
+
+  if (CTX_data_dir(member)) {
+    CTX_data_dir_set(result, file_context_dir);
+    return CTX_RESULT_OK;
+  }
+  else if (CTX_data_equals(member, "active_file")) {
+    FileDirEntry *file = filelist_file(sfile->files, params->active_file);
+    CTX_data_pointer_set(result, &screen->id, &RNA_FileSelectEntry, file);
+    return CTX_RESULT_OK;
+  }
+  else if (CTX_data_equals(member, "active_id")) {
+    const FileDirEntry *file = filelist_file(sfile->files, params->active_file);
+
+    ID *id = filelist_file_get_id(file);
+    if (id) {
+      CTX_data_id_pointer_set(result, id);
+    }
+    return CTX_RESULT_OK;
+  }
+  return CTX_RESULT_MEMBER_NOT_FOUND;
+}
+
+static void file_id_remap(ScrArea *area, SpaceLink *sl, ID *UNUSED(old_id), ID *UNUSED(new_id))
+{
+  SpaceFile *sfile = (SpaceFile *)sl;
+
+  /* If the file shows main data (IDs), tag it for reset. */
+  if (sfile->files && filelist_needs_reset_on_main_changes(sfile->files)) {
+    /* Full refresh of the file list if main data was changed, don't even attempt remap pointers.
+     * We could give file list types a id-remap callback, but it's probably not worth it.
+     * Refreshing local file lists is relatively cheap. */
+    file_tag_reset_list(area, sfile);
+  }
+}
+
 /* only called once, from space/spacetypes.c */
 void ED_spacetype_file(void)
 {
@@ -700,6 +779,8 @@ void ED_spacetype_file(void)
   st->operatortypes = file_operatortypes;
   st->keymap = file_keymap;
   st->dropboxes = file_dropboxes;
+  st->context = file_context;
+  st->id_remap = file_id_remap;
 
   /* regions: main window */
   art = MEM_callocN(sizeof(ARegionType), "spacetype file region");
diff --git a/source/blender/makesdna/DNA_space_types.h b/source/blender/makesdna/DNA_space_types.h
index 6fd112628a1..e07f085d356 100644
--- a/source/blender/makesdna/DNA_space_types.h
+++ b/source/blender/makesdna/DNA_space_types.h
@@ -664,6 +664,23 @@ typedef enum eSpaceSeq_OverlayType {
 /** \name File Selector
  * \{ */
 
+/**
+ * Information to identify a asset library. May be either one of the predefined types (current
+ * 'Main', builtin library, project library), or a custom type as defined in the Preferences.
+ *
+ * If the type is set to #FILE_ASSET_LIBRARY_CUSTOM, idname must have the name to identify the
+ * custom library. Otherwise idname is not used.
+ */
+typedef struct FileSelectAssetLibraryUID {
+  short type;
+  char _pad[6];
+  /**
+   * If showing a custom asset library (#FILE_ASSET_LIBRARY_CUSTOM), this name has to be set to
+   * define which. Can be empty otherwise.
+   */
+  char custom_library_identifier[64]; /* MAX_NAME */
+} FileSelectAssetLibraryUID;
+
 /* Config and Input for File Selector */
 typedef struct FileSelectParams {
   /** Title, also used for the text of the execute button. */
@@ -708,6 +725,7 @@ typedef struct FileSelectParams {
   /** Details toggles (file size, creation date, etc.) */
   char details_flags;
   char _pad2[3];
+
   /** Filter when (flags & FILE_FILTER) is true. */
   int filter;
 
@@ -723,6 +741,32 @@ typedef struct FileSelectParams {
   /* XXX --- end unused -- */
 } FileSelectParams;
 
+/**
+ * File selection parameters for asset browsing mode, with #FileSelectParams as base.
+ */
+typedef struct FileAssetSelectParams {
+  FileSelectParams base_params;
+
+  FileSelectAssetLibraryUID asset_library;
+} FileAssetSelectParams;
+
+/**
+ * A wrapper to store previous and next folder lists (#FolderList) for a specific browse mode
+ * (#eFileBrowse_Mode).
+ */
+typedef struct FileFolderHistory {
+  struct FileFolderLists *next, *prev;
+
+  /** The browse mode this prev/next folder-lists are created for. */
+  char browse_mode; /* eFileBrowse_Mode */
+  char _pad[7];
+
+  /** Holds the list of previous directories to show. */
+  ListBase folders_prev;
+  /** Holds the list of next directories (pushed from previous) to show. */
+  ListBase folders_next;
+} FileFolderHistory;
+
 /* File Browser */
 typedef struct SpaceFile {
   SpaceLink *next, *prev;
@@ -733,20 +777,42 @@ typedef struct SpaceFile {
   char _pad0[6];
   /* End 'SpaceLink' header. */
 
-  char _pad1[4];
+  /** Is this a File Browser or an Asset Browser? */
+  char browse_mode; /* eFileBrowse_Mode */
+  char _pad1[1];
+
+  short tags;
+
   int scroll_offset;
 
-  /** Config and input for file select. */
-  struct FileSelectParams *params;
+  /** Config and input for file select. One for each browse-mode, to keep them independent. */
+  FileSelectParams *params;
+  FileAssetSelectParams *asset_params;
 
-  /** Holds the list of files to show. */
+  void *_pad2;
+
+  /**
+   * Holds the list of files to show.
+   * Currently recreated when browse-mode changes. Could be per browse-mode to avoid refreshes.
+   */
   struct FileList *files;
 
-  /** Holds the list of previous directories to show. */
+  /**
+   * Holds the list of previous directories to show. Owned by `folder_histories` below.
+   */
   ListBase *folders_prev;
-  /** Holds the list of next directories (pushed from previous) to show. */
+  /**
+   * Holds the list of next directories (pushed from previous) to show. Owned by
+   * `folder_histories` below.
+   */
   ListBase *folders_next;
 
+  /**
+   * This actually owns the prev/next folder-lists above. On browse-mode change, the lists of the
+   * new mode get assigned to the above.
+   */
+  ListBase folder_histories; /* FileFolderHistory */
+
   /* operator that is invoking fileselect
    * op->exec() will be called on the 'Load' button.
    * if operator provides op->cancel(), then this will be invoked
@@ -763,6 +829,30 @@ typedef struct SpaceFile {
   short systemnr, system_bookmarknr;
 } SpaceFile;
 
+/* SpaceFile.browse_mode (File Space Browsing Mode) */
+typedef enum eFileBrowse_Mode {
+  /* Regular Blender File Browser */
+  FILE_BROWSE_MODE_FILES = 0,
+  /* Asset Browser */
+  FILE_BROWSE_MODE_ASSETS = 1,
+} eFileBrowse_Mode;
+
+typedef enum eFileAssetLibrary_Type {
+  /* For the future. Display assets bundled with Blender by default. */
+  // FILE_ASSET_LIBRARY_BUNDLED = 0,
+  /** Display assets from the current session (current "Main"). */
+  FILE_ASSET_LIBRARY_LOCAL = 1,
+  /* For the future. Display assets for the current project. */
+  // FILE_ASSET_LIBRARY_PROJECT = 2,
+
+  /** Display assets from custom asset libraries, as defined in the preferences
+   * (#bUserAssetLibrary). The name will be taken from #FileSelectParams.asset_library.idname
+   * then.
+   * In RNA, we add the index of the custom library to this to identify it by index. So keep
+   * this last! */
+  FILE_ASSET_LIBRARY_CUSTOM = 100,
+} eFileAssetLibrary_Type;
+
 /* FileSelectParams.display */
 enum eFileDisplayType {
   /** Internal (not exposed to users): Keep whatever display type was used during the last File
@@ -792,6 +882,13 @@ enum eFileSortType {
   FILE_SORT_SIZE = 4,
 };
 
+/* SpaceFile.tags */
+enum eFileTags {
+  /** Tag the space as having to update files representing or containing main data. Must be set
+   * after file read and undo/redo. */
+  FILE_TAG_REBUILD_MAIN_FILES = (1 << 0),
+};
+
 /* FileSelectParams.details_flags */
 enum eFileDetails {
   FILE_DETAILS_SIZE = (1 << 0),
@@ -810,6 +907,7 @@ enum eFileDetails {
 typedef enum eFileSelectType {
   FILE_LOADLIB = 1,
   FILE_MAIN = 2,
+  FILE_MAIN_ASSET = 3,
 
   FILE_UNIX = 8,
   FILE_BLENDER = 8, /* don't display relative paths */
@@ -842,6 +940,7 @@ typedef enum eFileSel_Params_Flag {
   FILE_SORT_INVERT = (1 << 11),
   FILE_HIDE_TOOL_PROPS = (1 << 12),
   FILE_CHECK_EXISTING = (1 << 13),
+  FILE_ASSETS_ONLY = (1 << 14),
 } eFileSel_Params_Flag;
 
 /* sfile->params->rename_flag */
@@ -885,6 +984,7 @@ typedef enum eFileSel_File_Types {
   FILE_TYPE_USD = (1 << 18),
   FILE_TYPE_VOLUME = (1 << 19),
 
+  FILE_TYPE_ASSET = (1 << 28),
   /** An FS directory (i.e. S_ISDIR on its path is true). */
   FILE_TYPE_DIR = (1 << 30),
   FILE_TYPE_BLENDERLIB = (1u << 31),
@@ -985,9 +1085,16 @@ typedef struct FileDirEntry {
   /** Optional argument for shortcuts, aliases etc. */
   char *redirection_path;
 
-  /** TODO: make this a real ID pointer? */
-  void *poin;
-  struct ImBuf *image;
+  /** When showing local IDs (FILE_MAIN, FILE_MAIN_ASSET), ID this file represents. Note comment
+   * for FileListInternEntry.local_data, the same applies here! */
+  ID *id;
+  /** If this file represents an asset, its asset data is here. Note that we may show assets of
+   * external files in which case this is set but not the id above.
+   * Note comment for FileListInternEntry.local_data, the same applies here! */
+  struct AssetMetaData *asset_data;
+
+  /* The icon_id for the preview image. */
+  int preview_icon_id;
 
   /* Tags are for info only, most of filtering is done in asset engine. */
   char **tags;
diff --git a/source/blender/makesrna/RNA_access.h b/source/blender/makesrna/RNA_access.h
index 0b0895f9db0..aaa948dbff6 100644
--- a/source/blender/makesrna/RNA_access.h
+++ b/source/blender/makesrna/RNA_access.h
@@ -253,7 +253,9 @@ extern StructRNA RNA_FModifierPython;
 extern StructRNA RNA_FModifierStepped;
 extern StructRNA RNA_FaceMap;
 extern StructRNA RNA_FieldSettings;
+extern StructRNA RNA_FileAssetSelectParams;
 extern StructRNA RNA_FileBrowserFSMenuEntry;
+extern StructRNA RNA_FileSelectEntry;
 extern StructRNA RNA_FileSelectParams;
 extern StructRNA RNA_FloatAttribute;
 extern StructRNA RNA_FloatAttributeValue;
diff --git a/source/blender/makesrna/RNA_enum_types.h b/source/blender/makesrna/RNA_enum_types.h
index a94466e30c2..69bd6142cad 100644
--- a/source/blender/makesrna/RNA_enum_types.h
+++ b/source/blender/makesrna/RNA_enum_types.h
@@ -56,6 +56,7 @@ extern const EnumPropertyItem rna_enum_mesh_select_mode_items[];
 extern const EnumPropertyItem rna_enum_mesh_select_mode_uv_items[];
 extern const EnumPropertyItem rna_enum_mesh_delimit_mode_items[];
 extern const EnumPropertyItem rna_enum_space_graph_mode_items[];
+extern const EnumPropertyItem rna_enum_space_file_browse_mode_items[];
 extern const EnumPropertyItem rna_enum_space_sequencer_view_type_items[];
 extern const EnumPropertyItem rna_enum_space_type_items[];
 extern const EnumPropertyItem rna_enum_space_image_mode_items[];
diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index 36dbb1c78cc..4b39858026c 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -170,6 +170,12 @@ const EnumPropertyItem rna_enum_space_sequencer_view_type_items[] = {
     {0, NULL, 0, NULL, NULL},
 };
 
+const EnumPropertyItem rna_enum_space_file_browse_mode_items[] = {
+    {FILE_BROWSE_MODE_FILES, "FILES", ICON_FILEBROWSER, "File Browser", ""},
+    {FILE_BROWSE_MODE_ASSETS, "ASSETS", ICON_ASSET_MANAGER, "Asset Browser", ""},
+    {0, NULL, 0, NULL, NULL},
+};
+
 #define SACT_ITEM_DOPESHEET \
   { \
     SACTCONT_DOPESHEET, "DOPESHEET", ICON_ACTION, "Dope Sheet", "Edit all keyframes in scene" \
@@ -504,6 +510,7 @@ static const EnumPropertyItem rna_enum_curve_display_handle_items[] = {
 #  include "BKE_layer.h"
 #  include "BKE_nla.h"
 #  include "BKE_paint.h"
+#  include "BKE_preferences.h"
 #  include "BKE_scene.h"
 #  include "BKE_screen.h"
 #  include "BKE_workspace.h"
@@ -2462,13 +2469,159 @@ static PointerRNA rna_FileSelectParams_filter_id_get(PointerRNA *ptr)
   return rna_pointer_inherit_refine(ptr, &RNA_FileSelectIDFilter, ptr->data);
 }
 
+static int rna_FileAssetSelectParams_asset_library_get(PointerRNA *ptr)
+{
+  FileAssetSelectParams *params = ptr->data;
+  /* Just an extra sanity check to ensure this isn't somehow called for RNA_FileSelectParams. */
+  BLI_assert(ptr->type == &RNA_FileAssetSelectParams);
+
+  /* Simple case: Predefined repo, just set the value. */
+  if (params->asset_library.type < FILE_ASSET_LIBRARY_CUSTOM) {
+    return params->asset_library.type;
+  }
+
+  /* Note that the path isn't checked for validity here. If an invalid library path is used, the
+   * Asset Browser can give a nice hint on what's wrong. */
+  const bUserAssetLibrary *user_library = BKE_preferences_asset_library_find_from_name(
+      &U, params->asset_library.custom_library_identifier);
+  const int index = BKE_preferences_asset_library_get_index(&U, user_library);
+  if (index > -1) {
+    return FILE_ASSET_LIBRARY_CUSTOM + index;
+  }
+
+  BLI_assert(0);
+  return FILE_ASSET_LIBRARY_LOCAL;
+}
+
+static void rna_FileAssetSelectParams_asset_library_set(PointerRNA *ptr, int value)
+{
+  FileAssetSelectParams *params = ptr->data;
+
+  /* Simple case: Predefined repo, just set the value. */
+  if (value < FILE_ASSET_LIBRARY_CUSTOM) {
+    params->asset_library.type = value;
+    params->asset_library.custom_library_identifier[0] = '\0';
+    BLI_assert(ELEM(value, FILE_ASSET_LIBRARY_LOCAL));
+    return;
+  }
+
+  const bUserAssetLibrary *user_library = BKE_preferences_asset_library_find_from_index(
+      &U, value - FILE_ASSET_LIBRARY_CUSTOM);
+
+  /* Note that the path isn't checked for validity here. If an invalid library path is used, the
+   * Asset Browser can give a nice hint on what's wrong. */
+  const bool is_valid = (user_library->name[0] && user_library->path[0]);
+  if (user_library && is_valid) {
+    BLI_strncpy(params->asset_library.custom_library_identifier,
+                user_library->name,
+                sizeof(params->asset_library.custom_library_identifier));
+    params->asset_library.type = FILE_ASSET_LIBRARY_CUSTOM;
+  }
+}
+
+static const EnumPropertyItem *rna_FileAssetSelectParams_asset_library_itemf(
+    bContext *UNUSED(C), PointerRNA *UNUSED(ptr), PropertyRNA *UNUSED(prop), bool *r_free)
+{
+  const EnumPropertyItem predefined_items[] = {
+      /* For the future. */
+      // {FILE_ASSET_REPO_BUNDLED, "BUNDLED", 0, "Bundled", "Show the default user assets"},
+      {FILE_ASSET_LIBRARY_LOCAL,
+       "LOCAL",
+       ICON_BLENDER,
+       "Current File",
+       "Show the assets currently available in this Blender session"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
+  EnumPropertyItem *item = NULL;
+  int totitem = 0;
+
+  /* Add separator if needed. */
+  if (!BLI_listbase_is_empty(&U.asset_libraries)) {
+    const EnumPropertyItem sepr = {0, "", 0, "Custom", NULL};
+    RNA_enum_item_add(&item, &totitem, &sepr);
+  }
+
+  int i = 0;
+  for (bUserAssetLibrary *user_library = U.asset_libraries.first; user_library;
+       user_library = user_library->next, i++) {
+    /* Note that the path itself isn't checked for validity here. If an invalid library path is
+     * used, the Asset Browser can give a nice hint on what's wrong. */
+    const bool is_valid = (user_library->name[0] && user_library->path[0]);
+    if (!is_valid) {
+      continue;
+    }
+
+    /* Use library path as description, it's a nice hint for users. */
+    EnumPropertyItem tmp = {FILE_ASSET_LIBRARY_CUSTOM + i,
+                            user_library->name,
+                            ICON_NONE,
+                            user_library->name,
+                            user_library->path};
+    RNA_enum_item_add(&item, &totitem, &tmp);
+  }
+
+  if (totitem) {
+    const EnumPropertyItem sepr = {0, "", 0, "Built-in", NULL};
+    RNA_enum_item_add(&item, &totitem, &sepr);
+  }
+
+  /* Add predefined items. */
+  RNA_enum_items_add(&item, &totitem, predefined_items);
+
+  RNA_enum_item_end(&item, &totitem);
+  *r_free = true;
+  return item;
+}
+
+static void rna_FileBrowser_FileSelectEntry_name_get(PointerRNA *ptr, char *value)
+{
+  const FileDirEntry *entry = ptr->data;
+  strcpy(value, entry->name);
+}
+
+static int rna_FileBrowser_FileSelectEntry_name_length(PointerRNA *ptr)
+{
+  const FileDirEntry *entry = ptr->data;
+  return (int)strlen(entry->name);
+}
+
+static int rna_FileBrowser_FileSelectEntry_preview_icon_id_get(PointerRNA *ptr)
+{
+  const FileDirEntry *entry = ptr->data;
+  return entry->preview_icon_id;
+}
+
+static PointerRNA rna_FileBrowser_FileSelectEntry_asset_data_get(PointerRNA *ptr)
+{
+  const FileDirEntry *entry = ptr->data;
+  return rna_pointer_inherit_refine(ptr, &RNA_AssetMetaData, entry->asset_data);
+}
+
+static StructRNA *rna_FileBrowser_params_typef(PointerRNA *ptr)
+{
+  SpaceFile *sfile = ptr->data;
+  FileSelectParams *params = ED_fileselect_get_active_params(sfile);
+
+  if (params == ED_fileselect_get_file_params(sfile)) {
+    return &RNA_FileSelectParams;
+  }
+  if (params == (void *)ED_fileselect_get_asset_params(sfile)) {
+    return &RNA_FileAssetSelectParams;
+  }
+
+  BLI_assert(!"Could not identify file select parameters");
+  return NULL;
+}
+
 static PointerRNA rna_FileBrowser_params_get(PointerRNA *ptr)
 {
   SpaceFile *sfile = ptr->data;
   FileSelectParams *params = ED_fileselect_get_active_params(sfile);
+  StructRNA *params_struct = rna_FileBrowser_params_typef(ptr);
 
-  if (params) {
-    return rna_pointer_inherit_refine(ptr, &RNA_FileSelectParams, params);
+  if (params && params_struct) {
+    return rna_pointer_inherit_refine(ptr, params_struct, params);
   }
 
   return rna_pointer_inherit_refine(ptr, NULL, NULL);
@@ -2784,6 +2937,14 @@ static void rna_FileBrowser_FSMenuRecent_active_range(
   rna_FileBrowser_FSMenu_active_range(ptr, min, max, softmin, softmax, FS_CATEGORY_RECENT);
 }
 
+static void rna_SpaceFileBrowser_browse_mode_update(Main *UNUSED(bmain),
+                                                    Scene *UNUSED(scene),
+                                                    PointerRNA *ptr)
+{
+  ScrArea *area = rna_area_from_space(ptr);
+  ED_area_tag_refresh(area);
+}
+
 #else
 
 static const EnumPropertyItem dt_uv_items[] = {
@@ -5794,6 +5955,44 @@ static void rna_def_fileselect_idfilter(BlenderRNA *brna)
   }
 }
 
+static void rna_def_fileselect_entry(BlenderRNA *brna)
+{
+  PropertyRNA *prop;
+  StructRNA *srna = RNA_def_struct(brna, "FileSelectEntry", NULL);
+  RNA_def_struct_sdna(srna, "FileDirEntry");
+  RNA_def_struct_ui_text(srna, "File Select Entry", "A file viewable in the File Browser");
+
+  prop = RNA_def_property(srna, "name", PROP_STRING, PROP_NONE);
+  RNA_def_property_string_funcs(prop,
+                                "rna_FileBrowser_FileSelectEntry_name_get",
+                                "rna_FileBrowser_FileSelectEntry_name_length",
+                                NULL);
+  RNA_def_property_ui_text(prop, "Name", "");
+  RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+  RNA_def_struct_name_property(srna, prop);
+
+  prop = RNA_def_int(
+      srna,
+      "preview_icon_id",
+      0,
+      INT_MIN,
+      INT_MAX,
+      "Icon ID",
+      "Unique integer identifying the preview of this file as an icon (zero means invalid)",
+      INT_MIN,
+      INT_MAX);
+  RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+  RNA_def_property_int_funcs(
+      prop, "rna_FileBrowser_FileSelectEntry_preview_icon_id_get", NULL, NULL);
+
+  prop = RNA_def_property(srna, "asset_data", PROP_POINTER, PROP_NONE);
+  RNA_def_property_struct_type(prop, "AssetMetaData");
+  RNA_def_property_pointer_funcs(
+      prop, "rna_FileBrowser_FileSelectEntry_asset_data_get", NULL, NULL, NULL);
+  RNA_def_property_ui_text(
+      prop, "Asset Data", "Asset data, valid if the file represents an asset");
+}
+
 static void rna_def_fileselect_params(BlenderRNA *brna)
 {
   StructRNA *srna;
@@ -5966,6 +6165,12 @@ static void rna_def_fileselect_params(BlenderRNA *brna)
   RNA_def_property_ui_icon(prop, ICON_BLENDER, 0);
   RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
 
+  prop = RNA_def_property(srna, "use_filter_asset_only", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", FILE_ASSETS_ONLY);
+  RNA_def_property_ui_text(
+      prop, "Only Assets", "Hide .blend files items that are not data-blocks with asset metadata");
+  RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
+
   prop = RNA_def_property(srna, "filter_id", PROP_POINTER, PROP_NONE);
   RNA_def_property_flag(prop, PROP_NEVER_NULL);
   RNA_def_property_struct_type(prop, "FileSelectIDFilter");
@@ -5997,6 +6202,25 @@ static void rna_def_fileselect_params(BlenderRNA *brna)
   RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_LIST, NULL);
 }
 
+static void rna_def_fileselect_asset_params(BlenderRNA *brna)
+{
+  StructRNA *srna;
+  PropertyRNA *prop;
+
+  srna = RNA_def_struct(brna, "FileAssetSelectParams", "FileSelectParams");
+  RNA_def_struct_ui_text(
+      srna, "Asset Select Parameters", "Settings for the file selection in Asset Browser mode");
+
+  prop = RNA_def_property(srna, "asset_library", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, DummyRNA_NULL_items);
+  RNA_def_property_enum_funcs(prop,
+                              "rna_FileAssetSelectParams_asset_library_get",
+                              "rna_FileAssetSelectParams_asset_library_set",
+                              "rna_FileAssetSelectParams_asset_library_itemf");
+  RNA_def_property_ui_text(prop, "Asset Library", "");
+  RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
+}
+
 static void rna_def_filemenu_entry(BlenderRNA *brna)
 {
   StructRNA *srna;
@@ -6050,9 +6274,18 @@ static void rna_def_space_filebrowser(BlenderRNA *brna)
 
   rna_def_space_generic_show_region_toggles(srna, (1 << RGN_TYPE_TOOLS) | (1 << RGN_TYPE_UI));
 
+  prop = RNA_def_property(srna, "browse_mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, rna_enum_space_file_browse_mode_items);
+  RNA_def_property_ui_text(
+      prop,
+      "Browsing Mode",
+      "Type of the File Editor view (regular file browsing or asset browsing)");
+  RNA_def_property_update(prop, 0, "rna_SpaceFileBrowser_browse_mode_update");
+
   prop = RNA_def_property(srna, "params", PROP_POINTER, PROP_NONE);
   RNA_def_property_struct_type(prop, "FileSelectParams");
-  RNA_def_property_pointer_funcs(prop, "rna_FileBrowser_params_get", NULL, NULL, NULL);
+  RNA_def_property_pointer_funcs(
+      prop, "rna_FileBrowser_params_get", NULL, "rna_FileBrowser_params_typef", NULL);
   RNA_def_property_ui_text(
       prop, "Filebrowser Parameter", "Parameters and Settings for the Filebrowser");
 
@@ -6800,7 +7033,9 @@ void RNA_def_space(BlenderRNA *brna)
   rna_def_space_image(brna);
   rna_def_space_sequencer(brna);
   rna_def_space_text(brna);
+  rna_def_fileselect_entry(brna);
   rna_def_fileselect_params(brna);
+  rna_def_fileselect_asset_params(brna);
   rna_def_fileselect_idfilter(brna);
   rna_def_filemenu_entry(brna);
   rna_def_space_filebrowser(brna);
diff --git a/source/blender/windowmanager/intern/wm_operator_props.c b/source/blender/windowmanager/intern/wm_operator_props.c
index 631a4d23eb5..fa658a5cdec 100644
--- a/source/blender/windowmanager/intern/wm_operator_props.c
+++ b/source/blender/windowmanager/intern/wm_operator_props.c
@@ -198,6 +198,8 @@ void WM_operator_properties_filesel(wmOperatorType *ot,
       ot->srna, "filter_blenlib", (filter & FILE_TYPE_BLENDERLIB) != 0, "Filter Blender IDs", "");
   RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
 
+  /* TODO asset only filter? */
+
   prop = RNA_def_int(
       ot->srna,
       "filemode",
-- 
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