/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright 2007 Blender Foundation. All rights reserved. */

/** \file
 * \ingroup spfile
 */

/* global includes */

#include <cmath>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <sys/stat.h>

#ifndef WIN32
#  include <unistd.h>
#else
#  include <direct.h>
#  include <io.h>
#endif
#include "MEM_guardedalloc.h"

#include "BLF_api.h"

#include "BLI_blenlib.h"
#include "BLI_fileops.h"
#include "BLI_fileops_types.h"
#include "BLI_fnmatch.h"
#include "BLI_ghash.h"
#include "BLI_linklist.h"
#include "BLI_math.h"
#include "BLI_stack.h"
#include "BLI_string_utils.h"
#include "BLI_task.h"
#include "BLI_threads.h"
#include "BLI_utildefines.h"
#include "BLI_uuid.h"

#ifdef WIN32
#  include "BLI_winstuff.h"
#endif

#include "BKE_asset.h"
#include "BKE_asset_library.h"
#include "BKE_asset_library.hh"
#include "BKE_asset_representation.hh"
#include "BKE_context.h"
#include "BKE_global.h"
#include "BKE_icons.h"
#include "BKE_idtype.h"
#include "BKE_lib_id.h"
#include "BKE_main.h"
#include "BKE_main_idmap.h"
#include "BKE_preferences.h"
#include "BLO_readfile.h"

#include "DNA_asset_types.h"
#include "DNA_space_types.h"

#include "ED_datafiles.h"
#include "ED_fileselect.h"
#include "ED_screen.h"

#include "IMB_imbuf.h"
#include "IMB_imbuf_types.h"
#include "IMB_thumbs.h"

#include "PIL_time.h"

#include "WM_api.h"
#include "WM_types.h"

#include "UI_interface_icons.h"
#include "UI_resources.h"

#include "atomic_ops.h"

#include "file_indexer.h"
#include "file_intern.h"
#include "filelist.h"

using namespace blender;

#define FILEDIR_NBR_ENTRIES_UNSET -1

/* ------------------FILELIST------------------------ */

struct FileListInternEntry {
  FileListInternEntry *next, *prev;

  FileUID uid;

  eFileSel_File_Types typeflag;
  /** ID type, in case typeflag has FILE_TYPE_BLENDERLIB set. */
  int blentype;

  char *relpath;
  /** Optional argument for shortcuts, aliases etc. */
  char *redirection_path;
  /** not strictly needed, but used during sorting, avoids to have to recompute it there... */
  const char *name;
  bool free_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;

  /* References an asset in the asset library storage. */
  bke::AssetRepresentation *asset; /* Non-owning. */

  /* See #FILE_ENTRY_BLENDERLIB_NO_PREVIEW. */
  bool blenderlib_has_no_preview;

  /** Defined in BLI_fileops.h */
  eFileAttributes attributes;
  BLI_stat_t st;
};

struct FileListIntern {
  /** FileListInternEntry items. */
  ListBase entries;
  FileListInternEntry **filtered;

  FileUID curr_uid; /* Used to generate UID during internal listing. */
};

#define FILELIST_ENTRYCACHESIZE_DEFAULT 1024 /* Keep it a power of two! */
struct FileListEntryCache {
  size_t size; /* The size of the cache... */

  int flags;

  /* This one gathers all entries from both block and misc caches. Used for easy bulk-freeing. */
  ListBase cached_entries;

  /* Block cache: all entries between start and end index.
   * used for part of the list on display. */
  FileDirEntry **block_entries;
  int block_start_index, block_end_index, block_center_index, block_cursor;

  /* Misc cache: random indices, FIFO behavior.
   * NOTE: Not 100% sure we actually need that, time will say. */
  int misc_cursor;
  int *misc_entries_indices;
  GHash *misc_entries;

  /* Allows to quickly get a cached entry from its UID. */
  GHash *uids;

  /* Previews handling. */
  TaskPool *previews_pool;
  ThreadQueue *previews_done;
  /** Counter for previews that are not fully loaded and ready to display yet. So includes all
   * previews either in `previews_pool` or `previews_done`. #filelist_cache_previews_update() makes
   * previews in `preview_done` ready for display, so the counter is decremented there. */
  int previews_todo_count;
};

/** #FileListCache.flags */
enum {
  FLC_IS_INIT = 1 << 0,
  FLC_PREVIEWS_ACTIVE = 1 << 1,
};

struct FileListEntryPreview {
  char filepath[FILE_MAX];
  uint flags;
  int index;
  int attributes; /* from FileDirEntry. */
  int icon_id;
};

/* Dummy wrapper around FileListEntryPreview to ensure we do not access freed memory when freeing
 * tasks' data (see T74609). */
struct FileListEntryPreviewTaskData {
  FileListEntryPreview *preview;
};

struct FileListFilter {
  uint64_t filter;
  uint64_t filter_id;
  char filter_glob[FILE_MAXFILE];
  char filter_search[66]; /* + 2 for heading/trailing implicit '*' wildcards. */
  short flags;

  FileAssetCatalogFilterSettingsHandle *asset_catalog_filter;
};

/** #FileListFilter.flags */
enum {
  FLF_DO_FILTER = 1 << 0,
  FLF_HIDE_DOT = 1 << 1,
  FLF_HIDE_PARENT = 1 << 2,
  FLF_HIDE_LIB_DIR = 1 << 3,
  FLF_ASSETS_ONLY = 1 << 4,
};

struct FileListReadJob;
struct FileList {
  FileDirEntryArr filelist;

  eFileSelectType type;
  /* The library this list was created for. Stored here so we know when to re-read. */
  AssetLibraryReference *asset_library_ref;
  bke::AssetLibrary *asset_library; /* Non-owning. */

  short flags;

  short sort;

  FileListFilter filter_data;

  /**
   * File indexer to use. Attribute is always set.
   */
  const FileIndexerType *indexer;

  FileListIntern filelist_intern;

  FileListEntryCache filelist_cache;

  /* We need to keep those info outside of actual filelist items,
   * because those are no more persistent
   * (only generated on demand, and freed as soon as possible).
   * Persistent part (mere list of paths + stat info)
   * is kept as small as possible, and file-browser agnostic.
   */
  GHash *selection_state;

  short max_recursion;
  short recursion_level;

  BlendHandle *libfiledata;

  /* Set given path as root directory,
   * if last bool is true may change given string in place to a valid value.
   * Returns True if valid dir. */
  bool (*check_dir_fn)(struct FileList *, char *, const bool);

  /* Fill filelist (to be called by read job). */
  void (*read_job_fn)(struct FileListReadJob *, bool *, bool *, float *);

  /* Filter an entry of current filelist. */
  bool (*filter_fn)(struct FileListInternEntry *, const char *, FileListFilter *);
  /* Executed before filtering individual items, to set up additional filter data. */
  void (*prepare_filter_fn)(const struct FileList *, FileListFilter *);

  short tags; /* FileListTags */
};

/** #FileList.flags */
enum {
  FL_FORCE_RESET = 1 << 0,
  /* Don't do a full reset (unless #FL_FORCE_RESET is also set), only reset files representing main
   * data (assets from the current file/#Main). */
  FL_FORCE_RESET_MAIN_FILES = 1 << 1,
  FL_IS_READY = 1 << 2,
  FL_IS_PENDING = 1 << 3,
  FL_NEED_SORTING = 1 << 4,
  FL_NEED_FILTERING = 1 << 5,
  FL_SORT_INVERT = 1 << 6,
};

/** #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

enum {
  SPECIAL_IMG_DOCUMENT = 0,
  SPECIAL_IMG_DRIVE_DISC = 1,
  SPECIAL_IMG_FOLDER = 2,
  SPECIAL_IMG_PARENT = 3,
  SPECIAL_IMG_DRIVE_FIXED = 4,
  SPECIAL_IMG_DRIVE_ATTACHED = 5,
  SPECIAL_IMG_DRIVE_REMOTE = 6,
  SPECIAL_IMG_MAX,
};

static ImBuf *gSpecialFileImages[SPECIAL_IMG_MAX];

static void filelist_readjob_main(FileListReadJob *job_params,
                                  bool *stop,
                                  bool *do_update,
                                  float *progress);
static void filelist_readjob_lib(FileListReadJob *job_params,
                                 bool *stop,
                                 bool *do_update,
                                 float *progress);
static void filelist_readjob_dir(FileListReadJob *job_params,
                                 bool *stop,
                                 bool *do_update,
                                 float *progress);
static void filelist_readjob_asset_library(FileListReadJob *job_params,
                                           bool *stop,
                                           bool *do_update,
                                           float *progress);
static void filelist_readjob_main_assets(FileListReadJob *job_params,
                                         bool *stop,
                                         bool *do_update,
                                         float *progress);

/* helper, could probably go in BKE actually? */
static int groupname_to_code(const char *group);
static uint64_t groupname_to_filter_id(const char *group);

static void filelist_cache_clear(FileListEntryCache *cache, size_t new_size);
static bool filelist_intern_entry_is_main_file(const FileListInternEntry *intern_entry);

/* ********** Sort helpers ********** */

struct FileSortData {
  bool inverted;
};

static int compare_apply_inverted(int val, const FileSortData *sort_data)
{
  return sort_data->inverted ? -val : val;
}

/**
 * If all relevant characteristics match (e.g. the file type when sorting by file types), this
 * should be used as tiebreaker. It makes sure there's a well defined sorting even in such cases.
 *
 * Multiple files with the same name can appear with recursive file loading and/or when displaying
 * IDs of different types, so these cases need to be handled.
 *
 * 1) Sort files by name using natural sorting.
 * 2) If not possible (file names match) and both represent local IDs, sort by ID-type.
 * 3) If not possible and only one is a local ID, place files representing local IDs first.
 *
 * TODO: (not actually implemented, but should be):
 * 4) If no file represents a local ID, sort by file path, so that files higher up the file system
 *    hierarchy are placed first.
 */
static int compare_tiebreaker(const FileListInternEntry *entry1, const FileListInternEntry *entry2)
{
  /* Case 1. */
  {
    const int order = BLI_strcasecmp_natural(entry1->name, entry2->name);
    if (order) {
      return order;
    }
  }

  /* Case 2. */
  if (entry1->local_data.id && entry2->local_data.id) {
    if (entry1->blentype < entry2->blentype) {
      return -1;
    }
    if (entry1->blentype > entry2->blentype) {
      return 1;
    }
  }
  /* Case 3. */
  {
    if (entry1->local_data.id && !entry2->local_data.id) {
      return -1;
    }
    if (!entry1->local_data.id && entry2->local_data.id) {
      return 1;
    }
  }

  return 0;
}

/**
 * Handles inverted sorting itself (currently there's nothing to invert), so if this returns non-0,
 * it should be used as-is and not inverted.
 */
static int compare_direntry_generic(const FileListInternEntry *entry1,
                                    const FileListInternEntry *entry2)
{
  /* type is equal to stat.st_mode */

  if (entry1->typeflag & FILE_TYPE_DIR) {
    if (entry2->typeflag & FILE_TYPE_DIR) {
      /* If both entries are tagged as dirs, we make a 'sub filter' that shows first the real dirs,
       * then libraries (.blend files), then categories in libraries. */
      if (entry1->typeflag & FILE_TYPE_BLENDERLIB) {
        if (!(entry2->typeflag & FILE_TYPE_BLENDERLIB)) {
          return 1;
        }
      }
      else if (entry2->typeflag & FILE_TYPE_BLENDERLIB) {
        return -1;
      }
      else if (entry1->typeflag & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) {
        if (!(entry2->typeflag & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP))) {
          return 1;
        }
      }
      else if (entry2->typeflag & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) {
        return -1;
      }
    }
    else {
      return -1;
    }
  }
  else if (entry2->typeflag & FILE_TYPE_DIR) {
    return 1;
  }

  /* make sure "." and ".." are always first */
  if (FILENAME_IS_CURRENT(entry1->relpath)) {
    return -1;
  }
  if (FILENAME_IS_CURRENT(entry2->relpath)) {
    return 1;
  }
  if (FILENAME_IS_PARENT(entry1->relpath)) {
    return -1;
  }
  if (FILENAME_IS_PARENT(entry2->relpath)) {
    return 1;
  }

  return 0;
}

static int compare_name(void *user_data, const void *a1, const void *a2)
{
  const FileListInternEntry *entry1 = static_cast<const FileListInternEntry *>(a1);
  const FileListInternEntry *entry2 = static_cast<const FileListInternEntry *>(a2);
  const FileSortData *sort_data = static_cast<const FileSortData *>(user_data);

  int ret;
  if ((ret = compare_direntry_generic(entry1, entry2))) {
    return ret;
  }

  return compare_apply_inverted(compare_tiebreaker(entry1, entry2), sort_data);
}

static int compare_date(void *user_data, const void *a1, const void *a2)
{
  const FileListInternEntry *entry1 = static_cast<const FileListInternEntry *>(a1);
  const FileListInternEntry *entry2 = static_cast<const FileListInternEntry *>(a2);
  const FileSortData *sort_data = static_cast<const FileSortData *>(user_data);
  int64_t time1, time2;

  int ret;
  if ((ret = compare_direntry_generic(entry1, entry2))) {
    return ret;
  }

  time1 = int64_t(entry1->st.st_mtime);
  time2 = int64_t(entry2->st.st_mtime);
  if (time1 < time2) {
    return compare_apply_inverted(1, sort_data);
  }
  if (time1 > time2) {
    return compare_apply_inverted(-1, sort_data);
  }

  return compare_apply_inverted(compare_tiebreaker(entry1, entry2), sort_data);
}

static int compare_size(void *user_data, const void *a1, const void *a2)
{
  const FileListInternEntry *entry1 = static_cast<const FileListInternEntry *>(a1);
  const FileListInternEntry *entry2 = static_cast<const FileListInternEntry *>(a2);
  const FileSortData *sort_data = static_cast<const FileSortData *>(user_data);
  uint64_t size1, size2;
  int ret;

  if ((ret = compare_direntry_generic(entry1, entry2))) {
    return ret;
  }

  size1 = entry1->st.st_size;
  size2 = entry2->st.st_size;
  if (size1 < size2) {
    return compare_apply_inverted(1, sort_data);
  }
  if (size1 > size2) {
    return compare_apply_inverted(-1, sort_data);
  }

  return compare_apply_inverted(compare_tiebreaker(entry1, entry2), sort_data);
}

static int compare_extension(void *user_data, const void *a1, const void *a2)
{
  const FileListInternEntry *entry1 = static_cast<const FileListInternEntry *>(a1);
  const FileListInternEntry *entry2 = static_cast<const FileListInternEntry *>(a2);
  const FileSortData *sort_data = static_cast<const FileSortData *>(user_data);
  int ret;

  if ((ret = compare_direntry_generic(entry1, entry2))) {
    return ret;
  }

  if ((entry1->typeflag & FILE_TYPE_BLENDERLIB) && !(entry2->typeflag & FILE_TYPE_BLENDERLIB)) {
    return -1;
  }
  if (!(entry1->typeflag & FILE_TYPE_BLENDERLIB) && (entry2->typeflag & FILE_TYPE_BLENDERLIB)) {
    return 1;
  }
  if ((entry1->typeflag & FILE_TYPE_BLENDERLIB) && (entry2->typeflag & FILE_TYPE_BLENDERLIB)) {
    if ((entry1->typeflag & FILE_TYPE_DIR) && !(entry2->typeflag & FILE_TYPE_DIR)) {
      return 1;
    }
    if (!(entry1->typeflag & FILE_TYPE_DIR) && (entry2->typeflag & FILE_TYPE_DIR)) {
      return -1;
    }
    if (entry1->blentype < entry2->blentype) {
      return compare_apply_inverted(-1, sort_data);
    }
    if (entry1->blentype > entry2->blentype) {
      return compare_apply_inverted(1, sort_data);
    }
  }
  else {
    const char *sufix1, *sufix2;

    if (!(sufix1 = strstr(entry1->relpath, ".blend.gz"))) {
      sufix1 = strrchr(entry1->relpath, '.');
    }
    if (!(sufix2 = strstr(entry2->relpath, ".blend.gz"))) {
      sufix2 = strrchr(entry2->relpath, '.');
    }
    if (!sufix1) {
      sufix1 = "";
    }
    if (!sufix2) {
      sufix2 = "";
    }

    if ((ret = BLI_strcasecmp(sufix1, sufix2))) {
      return compare_apply_inverted(ret, sort_data);
    }
  }

  return compare_apply_inverted(compare_tiebreaker(entry1, entry2), sort_data);
}

void filelist_sort(struct FileList *filelist)
{
  if (filelist->flags & FL_NEED_SORTING) {
    int (*sort_cb)(void *, const void *, const void *) = nullptr;

    switch (filelist->sort) {
      case FILE_SORT_ALPHA:
        sort_cb = compare_name;
        break;
      case FILE_SORT_TIME:
        sort_cb = compare_date;
        break;
      case FILE_SORT_SIZE:
        sort_cb = compare_size;
        break;
      case FILE_SORT_EXTENSION:
        sort_cb = compare_extension;
        break;
      case FILE_SORT_DEFAULT:
      default:
        BLI_assert(0);
        break;
    }

    FileSortData sort_data{};
    sort_data.inverted = (filelist->flags & FL_SORT_INVERT) != 0;
    BLI_listbase_sort_r(&filelist->filelist_intern.entries, sort_cb, &sort_data);

    filelist_tag_needs_filtering(filelist);
    filelist->flags &= ~FL_NEED_SORTING;
  }
}

void filelist_setsorting(struct FileList *filelist, const short sort, bool invert_sort)
{
  const bool was_invert_sort = filelist->flags & FL_SORT_INVERT;

  if ((filelist->sort != sort) || (was_invert_sort != invert_sort)) {
    filelist->sort = sort;
    filelist->flags |= FL_NEED_SORTING;
    filelist->flags = invert_sort ? (filelist->flags | FL_SORT_INVERT) :
                                    (filelist->flags & ~FL_SORT_INVERT);
  }
}

/* ********** Filter helpers ********** */

/* True if filename is meant to be hidden, eg. starting with period. */
static bool is_hidden_dot_filename(const char *filename, const FileListInternEntry *file)
{
  if (filename[0] == '.' && !ELEM(filename[1], '.', '\0')) {
    return true; /* ignore .file */
  }

  int len = strlen(filename);
  if ((len > 0) && (filename[len - 1] == '~')) {
    return true; /* ignore file~ */
  }

  /* filename might actually be a piece of path, in which case we have to check all its parts. */

  bool hidden = false;
  char *sep = (char *)BLI_path_slash_rfind(filename);

  if (!hidden && sep) {
    char tmp_filename[FILE_MAX_LIBEXTRA];

    BLI_strncpy(tmp_filename, filename, sizeof(tmp_filename));
    sep = tmp_filename + (sep - filename);
    while (sep) {
      /* This happens when a path contains 'ALTSEP', '\' on Unix for e.g.
       * Supporting alternate slashes in paths is a bigger task involving changes
       * in many parts of the code, for now just prevent an assert, see T74579. */
#if 0
      BLI_assert(sep[1] != '\0');
#endif
      if (is_hidden_dot_filename(sep + 1, file)) {
        hidden = true;
        break;
      }
      *sep = '\0';
      sep = (char *)BLI_path_slash_rfind(tmp_filename);
    }
  }
  return hidden;
}

/* True if should be hidden, based on current filtering. */
static bool is_filtered_hidden(const char *filename,
                               const FileListFilter *filter,
                               const FileListInternEntry *file)
{
  if ((filename[0] == '.') && (filename[1] == '\0')) {
    return true; /* Ignore. */
  }

  if (filter->flags & FLF_HIDE_PARENT) {
    if (filename[0] == '.' && filename[1] == '.' && filename[2] == '\0') {
      return true; /* Ignore. */
    }
  }

  if ((filter->flags & FLF_HIDE_DOT) && (file->attributes & FILE_ATTR_HIDDEN)) {
    return true; /* Ignore files with Hidden attribute. */
  }

#ifndef WIN32
  /* Check for unix-style names starting with period. */
  if ((filter->flags & FLF_HIDE_DOT) && is_hidden_dot_filename(filename, file)) {
    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;
}

/**
 * Apply the filter string as file path matching pattern.
 * \return true when the file should be in the result set, false if it should be filtered out.
 */
static bool is_filtered_file_relpath(const FileListInternEntry *file, const FileListFilter *filter)
{
  if (filter->filter_search[0] == '\0') {
    return true;
  }

  /* If there's a filter string, apply it as filter even if FLF_DO_FILTER is not set. */
  return fnmatch(filter->filter_search, file->relpath, FNM_CASEFOLD) == 0;
}

/**
 * Apply the filter string as matching pattern on file name.
 * \return true when the file should be in the result set, false if it should be filtered out.
 */
static bool is_filtered_file_name(const FileListInternEntry *file, const FileListFilter *filter)
{
  if (filter->filter_search[0] == '\0') {
    return true;
  }

  /* If there's a filter string, apply it as filter even if FLF_DO_FILTER is not set. */
  return fnmatch(filter->filter_search, file->name, FNM_CASEFOLD) == 0;
}

/** \return true when the file should be in the result set, false if it should be filtered out. */
static bool is_filtered_file_type(const FileListInternEntry *file, const FileListFilter *filter)
{
  if (is_filtered_hidden(file->relpath, filter, file)) {
    return false;
  }

  if (FILENAME_IS_CURRPAR(file->relpath)) {
    return false;
  }

  /* We only check for types if some type are enabled in filtering. */
  if (filter->filter && (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))) {
          return false;
        }
      }
      else {
        if (!(filter->filter & FILE_TYPE_FOLDER)) {
          return false;
        }
      }
    }
    else {
      if (!(file->typeflag & filter->filter)) {
        return false;
      }
    }
  }
  return true;
}

/** \return true when the file should be in the result set, false if it should be filtered out. */
static bool is_filtered_file(FileListInternEntry *file,
                             const char * /*root*/,
                             FileListFilter *filter)
{
  return is_filtered_file_type(file, filter) &&
         (is_filtered_file_relpath(file, filter) || is_filtered_file_name(file, filter));
}

static bool is_filtered_id_file_type(const FileListInternEntry *file,
                                     const char *id_group,
                                     const char *name,
                                     const FileListFilter *filter)
{
  if (!is_filtered_file_type(file, filter)) {
    return false;
  }

  /* We only check for types if some type are enabled in filtering. */
  if ((filter->filter || filter->filter_id) && (filter->flags & FLF_DO_FILTER)) {
    if (id_group) {
      if (!name && (filter->flags & FLF_HIDE_LIB_DIR)) {
        return false;
      }

      uint64_t filter_id = groupname_to_filter_id(id_group);
      if (!(filter_id & filter->filter_id)) {
        return false;
      }
    }
  }

  return true;
}

/**
 * Get the asset metadata of a file, if it represents an asset. This may either be of a local ID
 * (ID in the current #Main) or read from an external asset library.
 */
static AssetMetaData *filelist_file_internal_get_asset_data(const FileListInternEntry *file)
{
  if (!file->asset) {
    return nullptr;
  }
  return &file->asset->get_metadata();
}

static void prepare_filter_asset_library(const FileList *filelist, FileListFilter *filter)
{
  /* Not used yet for the asset view template. */
  if (!filter->asset_catalog_filter) {
    return;
  }
  BLI_assert_msg(filelist->asset_library,
                 "prepare_filter_asset_library() should only be called when the file browser is "
                 "in asset browser mode");

  file_ensure_updated_catalog_filter_data(filter->asset_catalog_filter, filelist->asset_library);
}

/**
 * Return whether at least one tag matches the search filter.
 * Tags are searched as "entire words", so instead of searching for "tag" in the
 * filter string, this function searches for " tag ". Assumes the search filter
 * starts and ends with a space.
 *
 * Here the tags on the asset are written in set notation:
 *
 * `asset_tag_matches_filter(" some tags ", {"some", "blue"})` -> true
 * `asset_tag_matches_filter(" some tags ", {"som", "tag"})` -> false
 * `asset_tag_matches_filter(" some tags ", {})` -> false
 */
static bool asset_tag_matches_filter(const char *filter_search, const AssetMetaData *asset_data)
{
  LISTBASE_FOREACH (const AssetTag *, asset_tag, &asset_data->tags) {
    if (BLI_strcasestr(asset_tag->name, filter_search) != nullptr) {
      return true;
    }
  }
  return false;
}

static bool is_filtered_asset(FileListInternEntry *file, FileListFilter *filter)
{
  const AssetMetaData *asset_data = filelist_file_internal_get_asset_data(file);

  /* Not used yet for the asset view template. */
  if (filter->asset_catalog_filter && !file_is_asset_visible_in_catalog_filter_settings(
                                          filter->asset_catalog_filter, asset_data)) {
    return false;
  }

  if (filter->filter_search[0] == '\0') {
    /* If there is no filter text, everything matches. */
    return true;
  }

  /* filter->filter_search contains "*the search text*". */
  char filter_search[66]; /* sizeof(FileListFilter::filter_search) */
  const size_t string_length = STRNCPY_RLEN(filter_search, filter->filter_search);

  /* When doing a name comparison, get rid of the leading/trailing asterisks. */
  filter_search[string_length - 1] = '\0';
  if (BLI_strcasestr(file->name, filter_search + 1) != nullptr) {
    return true;
  }
  return asset_tag_matches_filter(filter_search + 1, asset_data);
}

static bool is_filtered_lib_type(FileListInternEntry *file,
                                 const char *root,
                                 FileListFilter *filter)
{
  char path[FILE_MAX_LIBEXTRA], dir[FILE_MAX_LIBEXTRA], *group, *name;

  BLI_path_join(path, sizeof(path), root, file->relpath);

  if (BLO_library_path_explode(path, dir, &group, &name)) {
    return is_filtered_id_file_type(file, group, name, filter);
  }
  return is_filtered_file_type(file, filter);
}

static bool is_filtered_lib(FileListInternEntry *file, const char *root, FileListFilter *filter)
{
  return is_filtered_lib_type(file, root, filter) && is_filtered_file_relpath(file, filter);
}

static bool is_filtered_main(FileListInternEntry *file,
                             const char * /*dir*/,
                             FileListFilter *filter)
{
  return !is_filtered_hidden(file->relpath, filter, file);
}

static bool is_filtered_main_assets(FileListInternEntry *file,
                                    const char * /*dir*/,
                                    FileListFilter *filter)
{
  /* "Filtered" means *not* being filtered out... So return true if the file should be visible. */
  return is_filtered_id_file_type(file, file->relpath, file->name, filter) &&
         is_filtered_asset(file, filter);
}

static bool is_filtered_asset_library(FileListInternEntry *file,
                                      const char *root,
                                      FileListFilter *filter)
{
  if (filelist_intern_entry_is_main_file(file)) {
    return is_filtered_main_assets(file, root, filter);
  }

  return is_filtered_lib_type(file, root, filter) && is_filtered_asset(file, filter);
}

void filelist_tag_needs_filtering(FileList *filelist)
{
  filelist->flags |= FL_NEED_FILTERING;
}

void filelist_filter(FileList *filelist)
{
  int num_filtered = 0;
  const int num_files = filelist->filelist.entries_num;
  FileListInternEntry **filtered_tmp;

  if (ELEM(filelist->filelist.entries_num, FILEDIR_NBR_ENTRIES_UNSET, 0)) {
    return;
  }

  if (!(filelist->flags & FL_NEED_FILTERING)) {
    /* Assume it has already been filtered, nothing else to do! */
    return;
  }

  filelist->filter_data.flags &= ~FLF_HIDE_LIB_DIR;
  if (filelist->max_recursion) {
    /* Never show lib ID 'categories' directories when we are in 'flat' mode, unless
     * root path is a blend file. */
    char dir[FILE_MAX_LIBEXTRA];
    if (!filelist_islibrary(filelist, dir, nullptr)) {
      filelist->filter_data.flags |= FLF_HIDE_LIB_DIR;
    }
  }

  if (filelist->prepare_filter_fn) {
    filelist->prepare_filter_fn(filelist, &filelist->filter_data);
  }

  filtered_tmp = static_cast<FileListInternEntry **>(
      MEM_mallocN(sizeof(*filtered_tmp) * size_t(num_files), __func__));

  /* Filter remap & count how many files are left after filter in a single loop. */
  LISTBASE_FOREACH (FileListInternEntry *, file, &filelist->filelist_intern.entries) {
    if (filelist->filter_fn(file, filelist->filelist.root, &filelist->filter_data)) {
      filtered_tmp[num_filtered++] = file;
    }
  }

  if (filelist->filelist_intern.filtered) {
    MEM_freeN(filelist->filelist_intern.filtered);
  }
  filelist->filelist_intern.filtered = static_cast<FileListInternEntry **>(
      MEM_mallocN(sizeof(*filelist->filelist_intern.filtered) * size_t(num_filtered), __func__));
  memcpy(filelist->filelist_intern.filtered,
         filtered_tmp,
         sizeof(*filelist->filelist_intern.filtered) * size_t(num_filtered));
  filelist->filelist.entries_filtered_num = num_filtered;
  //  printf("Filetered: %d over %d entries\n", num_filtered, filelist->filelist.entries_num);

  filelist_cache_clear(&filelist->filelist_cache, filelist->filelist_cache.size);
  filelist->flags &= ~FL_NEED_FILTERING;

  MEM_freeN(filtered_tmp);
}

void filelist_setfilter_options(FileList *filelist,
                                const bool do_filter,
                                const bool hide_dot,
                                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)
{
  bool update = false;

  if (((filelist->filter_data.flags & FLF_DO_FILTER) != 0) != (do_filter != 0)) {
    filelist->filter_data.flags ^= FLF_DO_FILTER;
    update = true;
  }
  if (((filelist->filter_data.flags & FLF_HIDE_DOT) != 0) != (hide_dot != 0)) {
    filelist->filter_data.flags ^= FLF_HIDE_DOT;
    update = true;
  }
  if (((filelist->filter_data.flags & FLF_HIDE_PARENT) != 0) != (hide_parent != 0)) {
    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;
  }
  const uint64_t new_filter_id = (filter & FILE_TYPE_BLENDERLIB) ? filter_id : FILTER_ID_ALL;
  if (filelist->filter_data.filter_id != new_filter_id) {
    filelist->filter_data.filter_id = new_filter_id;
    update = true;
  }
  if (!STREQ(filelist->filter_data.filter_glob, filter_glob)) {
    BLI_strncpy(
        filelist->filter_data.filter_glob, filter_glob, sizeof(filelist->filter_data.filter_glob));
    update = true;
  }
  if (BLI_strcmp_ignore_pad(filelist->filter_data.filter_search, filter_search, '*') != 0) {
    BLI_strncpy_ensure_pad(filelist->filter_data.filter_search,
                           filter_search,
                           '*',
                           sizeof(filelist->filter_data.filter_search));
    update = true;
  }

  if (update) {
    /* And now, free filtered data so that we know we have to filter again. */
    filelist_tag_needs_filtering(filelist);
  }
}

void filelist_setindexer(FileList *filelist, const FileIndexerType *indexer)
{
  BLI_assert(filelist);
  BLI_assert(indexer);

  filelist->indexer = indexer;
}

void filelist_set_asset_catalog_filter_options(
    FileList *filelist,
    eFileSel_Params_AssetCatalogVisibility catalog_visibility,
    const ::bUUID *catalog_id)
{
  if (!filelist->filter_data.asset_catalog_filter) {
    /* There's no filter data yet. */
    filelist->filter_data.asset_catalog_filter = file_create_asset_catalog_filter_settings();
  }

  const bool needs_update = file_set_asset_catalog_filter_settings(
      filelist->filter_data.asset_catalog_filter, catalog_visibility, *catalog_id);

  if (needs_update) {
    filelist_tag_needs_filtering(filelist);
  }
}

/**
 * Checks two libraries for equality.
 * \return True if the libraries match.
 */
static bool filelist_compare_asset_libraries(const AssetLibraryReference *library_a,
                                             const AssetLibraryReference *library_b)
{
  if (library_a->type != library_b->type) {
    return false;
  }
  if (library_a->type == ASSET_LIBRARY_CUSTOM) {
    /* Don't only check the index, also check that it's valid. */
    bUserAssetLibrary *library_ptr_a = BKE_preferences_asset_library_find_from_index(
        &U, library_a->custom_library_index);
    return (library_ptr_a != nullptr) &&
           (library_a->custom_library_index == library_b->custom_library_index);
  }

  return true;
}

void filelist_setlibrary(FileList *filelist, const AssetLibraryReference *asset_library_ref)
{
  /* Unset if needed. */
  if (!asset_library_ref) {
    if (filelist->asset_library_ref) {
      MEM_SAFE_FREE(filelist->asset_library_ref);
      filelist->flags |= FL_FORCE_RESET;
    }
    return;
  }

  if (!filelist->asset_library_ref) {
    filelist->asset_library_ref = MEM_new<AssetLibraryReference>("filelist asset library");
    *filelist->asset_library_ref = *asset_library_ref;

    filelist->flags |= FL_FORCE_RESET;
  }
  else if (!filelist_compare_asset_libraries(filelist->asset_library_ref, asset_library_ref)) {
    *filelist->asset_library_ref = *asset_library_ref;
    filelist->flags |= FL_FORCE_RESET;
  }
}

/* ********** Icon/image helpers ********** */

void filelist_init_icons(void)
{
  short x, y, k;
  ImBuf *bbuf;
  ImBuf *ibuf;

  BLI_assert(G.background == false);

#ifdef WITH_HEADLESS
  bbuf = nullptr;
#else
  bbuf = IMB_ibImageFromMemory((const uchar *)datatoc_prvicons_png,
                               datatoc_prvicons_png_size,
                               IB_rect,
                               nullptr,
                               "<splash>");
#endif
  if (bbuf) {
    for (y = 0; y < SPECIAL_IMG_ROWS; y++) {
      for (x = 0; x < SPECIAL_IMG_COLS; x++) {
        int tile = SPECIAL_IMG_COLS * y + x;
        if (tile < SPECIAL_IMG_MAX) {
          ibuf = IMB_allocImBuf(SPECIAL_IMG_SIZE, SPECIAL_IMG_SIZE, 32, IB_rect);
          for (k = 0; k < SPECIAL_IMG_SIZE; k++) {
            memcpy(&ibuf->rect[k * SPECIAL_IMG_SIZE],
                   &bbuf->rect[(k + y * SPECIAL_IMG_SIZE) * SPECIAL_IMG_SIZE * SPECIAL_IMG_COLS +
                               x * SPECIAL_IMG_SIZE],
                   SPECIAL_IMG_SIZE * sizeof(int));
          }
          gSpecialFileImages[tile] = ibuf;
        }
      }
    }
    IMB_freeImBuf(bbuf);
  }
}

void filelist_free_icons(void)
{
  BLI_assert(G.background == false);

  for (int i = 0; i < SPECIAL_IMG_MAX; i++) {
    IMB_freeImBuf(gSpecialFileImages[i]);
    gSpecialFileImages[i] = nullptr;
  }
}

static FileDirEntry *filelist_geticon_get_file(struct FileList *filelist, const int index)
{
  BLI_assert(G.background == false);

  return filelist_file(filelist, index);
}

ImBuf *filelist_getimage(struct FileList *filelist, const int index)
{
  FileDirEntry *file = filelist_geticon_get_file(filelist, index);

  return file->preview_icon_id ? BKE_icon_imbuf_get_buffer(file->preview_icon_id) : nullptr;
}

ImBuf *filelist_file_getimage(const FileDirEntry *file)
{
  return file->preview_icon_id ? BKE_icon_imbuf_get_buffer(file->preview_icon_id) : nullptr;
}

ImBuf *filelist_geticon_image_ex(const FileDirEntry *file)
{
  ImBuf *ibuf = nullptr;

  if (file->typeflag & FILE_TYPE_DIR) {
    if (FILENAME_IS_PARENT(file->relpath)) {
      ibuf = gSpecialFileImages[SPECIAL_IMG_PARENT];
    }
    else {
      ibuf = gSpecialFileImages[SPECIAL_IMG_FOLDER];
    }
  }
  else {
    ibuf = gSpecialFileImages[SPECIAL_IMG_DOCUMENT];
  }

  return ibuf;
}

ImBuf *filelist_geticon_image(struct FileList *filelist, const int index)
{
  FileDirEntry *file = filelist_geticon_get_file(filelist, index);
  return filelist_geticon_image_ex(file);
}

static int filelist_geticon_ex(const FileDirEntry *file,
                               const char *root,
                               const bool is_main,
                               const bool ignore_libdir)
{
  const eFileSel_File_Types typeflag = (eFileSel_File_Types)file->typeflag;

  if ((typeflag & FILE_TYPE_DIR) &&
      !(ignore_libdir && (typeflag & (FILE_TYPE_BLENDERLIB | FILE_TYPE_BLENDER)))) {
    if (FILENAME_IS_PARENT(file->relpath)) {
      return is_main ? ICON_FILE_PARENT : ICON_NONE;
    }
    if (typeflag & FILE_TYPE_BUNDLE) {
      return ICON_UGLYPACKAGE;
    }
    if (typeflag & FILE_TYPE_BLENDER) {
      return ICON_FILE_BLEND;
    }
    if (is_main) {
      /* Do not return icon for folders if icons are not 'main' draw type
       * (e.g. when used over previews). */
      return (file->attributes & FILE_ATTR_ANY_LINK) ? ICON_FOLDER_REDIRECT : ICON_FILE_FOLDER;
    }

    /* If this path is in System list or path cache then use that icon. */
    struct FSMenu *fsmenu = ED_fsmenu_get();
    FSMenuCategory categories[] = {
        FS_CATEGORY_SYSTEM,
        FS_CATEGORY_SYSTEM_BOOKMARKS,
        FS_CATEGORY_OTHER,
    };

    for (int i = 0; i < ARRAY_SIZE(categories); i++) {
      FSMenuEntry *tfsm = ED_fsmenu_get_category(fsmenu, categories[i]);
      char fullpath[FILE_MAX_LIBEXTRA];
      char *target = fullpath;
      if (file->redirection_path) {
        target = file->redirection_path;
      }
      else if (root) {
        BLI_path_join(fullpath, sizeof(fullpath), root, file->relpath);
        BLI_path_slash_ensure(fullpath, sizeof(fullpath));
      }
      for (; tfsm; tfsm = tfsm->next) {
        if (STREQ(tfsm->path, target)) {
          /* Never want a little folder inside a large one. */
          return (tfsm->icon == ICON_FILE_FOLDER) ? ICON_NONE : tfsm->icon;
        }
      }
    }

    if (file->attributes & FILE_ATTR_OFFLINE) {
      return ICON_ERROR;
    }
    if (file->attributes & FILE_ATTR_TEMPORARY) {
      return ICON_FILE_CACHE;
    }
    if (file->attributes & FILE_ATTR_SYSTEM) {
      return ICON_SYSTEM;
    }
  }

  if (typeflag & FILE_TYPE_BLENDER) {
    return (is_main || file->preview_icon_id) ? ICON_FILE_BLEND : ICON_BLENDER;
  }
  if (typeflag & FILE_TYPE_BLENDER_BACKUP) {
    return ICON_FILE_BACKUP;
  }
  if (typeflag & FILE_TYPE_IMAGE) {
    return ICON_FILE_IMAGE;
  }
  if (typeflag & FILE_TYPE_MOVIE) {
    return ICON_FILE_MOVIE;
  }
  if (typeflag & FILE_TYPE_PYSCRIPT) {
    return ICON_FILE_SCRIPT;
  }
  if (typeflag & FILE_TYPE_SOUND) {
    return ICON_FILE_SOUND;
  }
  if (typeflag & FILE_TYPE_FTFONT) {
    return ICON_FILE_FONT;
  }
  if (typeflag & FILE_TYPE_BTX) {
    return ICON_FILE_BLANK;
  }
  if (typeflag & FILE_TYPE_COLLADA) {
    return ICON_FILE_3D;
  }
  if (typeflag & FILE_TYPE_ALEMBIC) {
    return ICON_FILE_3D;
  }
  if (typeflag & FILE_TYPE_USD) {
    return ICON_FILE_3D;
  }
  if (typeflag & FILE_TYPE_VOLUME) {
    return ICON_FILE_VOLUME;
  }
  if (typeflag & FILE_TYPE_OBJECT_IO) {
    return ICON_FILE_3D;
  }
  if (typeflag & FILE_TYPE_TEXT) {
    return ICON_FILE_TEXT;
  }
  if (typeflag & FILE_TYPE_ARCHIVE) {
    return ICON_FILE_ARCHIVE;
  }
  if (typeflag & FILE_TYPE_BLENDERLIB) {
    const int ret = UI_icon_from_idcode(file->blentype);
    if (ret != ICON_NONE) {
      return ret;
    }
  }
  return is_main ? ICON_FILE_BLANK : ICON_NONE;
}

int filelist_geticon(struct FileList *filelist, const int index, const bool is_main)
{
  FileDirEntry *file = filelist_geticon_get_file(filelist, index);

  return filelist_geticon_ex(file, filelist->filelist.root, is_main, false);
}

int ED_file_icon(const FileDirEntry *file)
{
  return file->preview_icon_id ? file->preview_icon_id :
                                 filelist_geticon_ex(file, nullptr, false, false);
}

static bool filelist_intern_entry_is_main_file(const FileListInternEntry *intern_entry)
{
  return intern_entry->local_data.id != nullptr;
}

/* ********** Main ********** */

static void parent_dir_until_exists_or_default_root(char *dir)
{
  if (!BLI_path_parent_dir_until_exists(dir)) {
#ifdef WIN32
    BLI_windows_get_default_root_dir(dir);
#else
    strcpy(dir, "/");
#endif
  }
}

static bool filelist_checkdir_dir(struct FileList * /*filelist*/,
                                  char *r_dir,
                                  const bool do_change)
{
  if (do_change) {
    parent_dir_until_exists_or_default_root(r_dir);
    return true;
  }
  return BLI_is_dir(r_dir);
}

static bool filelist_checkdir_lib(struct FileList * /*filelist*/,
                                  char *r_dir,
                                  const bool do_change)
{
  char tdir[FILE_MAX_LIBEXTRA];
  char *name;

  const bool is_valid = (BLI_is_dir(r_dir) ||
                         (BLO_library_path_explode(r_dir, tdir, nullptr, &name) &&
                          BLI_is_file(tdir) && !name));

  if (do_change && !is_valid) {
    /* if not a valid library, we need it to be a valid directory! */
    parent_dir_until_exists_or_default_root(r_dir);
    return true;
  }
  return is_valid;
}

static bool filelist_checkdir_main(struct FileList *filelist, char *r_dir, const bool do_change)
{
  /* TODO */
  return filelist_checkdir_lib(filelist, r_dir, do_change);
}

static bool filelist_checkdir_main_assets(struct FileList * /*filelist*/,
                                          char * /*r_dir*/,
                                          const bool /*do_change*/)
{
  /* Main is always valid. */
  return true;
}

static void filelist_entry_clear(FileDirEntry *entry)
{
  if (entry->name && ((entry->flags & FILE_ENTRY_NAME_FREE) != 0)) {
    MEM_freeN((char *)entry->name);
  }
  if (entry->relpath) {
    MEM_freeN(entry->relpath);
  }
  if (entry->redirection_path) {
    MEM_freeN(entry->redirection_path);
  }
  if (entry->preview_icon_id) {
    BKE_icon_delete(entry->preview_icon_id);
    entry->preview_icon_id = 0;
  }
}

static void filelist_entry_free(FileDirEntry *entry)
{
  filelist_entry_clear(entry);
  MEM_freeN(entry);
}

static void filelist_direntryarr_free(FileDirEntryArr *array)
{
#if 0
  FileDirEntry *entry, *entry_next;

  for (entry = array->entries.first; entry; entry = entry_next) {
    entry_next = entry->next;
    filelist_entry_free(entry);
  }
  BLI_listbase_clear(&array->entries);
#else
  BLI_assert(BLI_listbase_is_empty(&array->entries));
#endif
  array->entries_num = FILEDIR_NBR_ENTRIES_UNSET;
  array->entries_filtered_num = FILEDIR_NBR_ENTRIES_UNSET;
}

static void filelist_intern_entry_free(FileList *filelist, FileListInternEntry *entry)
{
  if (entry->asset) {
    BLI_assert(filelist->asset_library);
    filelist->asset_library->remove_asset(*entry->asset);
  }

  if (entry->relpath) {
    MEM_freeN(entry->relpath);
  }
  if (entry->redirection_path) {
    MEM_freeN(entry->redirection_path);
  }
  if (entry->name && entry->free_name) {
    MEM_freeN((char *)entry->name);
  }
  MEM_freeN(entry);
}

static void filelist_intern_free(FileList *filelist)
{
  FileListIntern *filelist_intern = &filelist->filelist_intern;
  LISTBASE_FOREACH_MUTABLE (FileListInternEntry *, entry, &filelist_intern->entries) {
    filelist_intern_entry_free(filelist, entry);
  }
  BLI_listbase_clear(&filelist_intern->entries);

  MEM_SAFE_FREE(filelist_intern->filtered);
}

/**
 * \return the number of main files removed.
 */
static int filelist_intern_free_main_files(FileList *filelist)
{
  FileListIntern *filelist_intern = &filelist->filelist_intern;
  int removed_counter = 0;
  LISTBASE_FOREACH_MUTABLE (FileListInternEntry *, entry, &filelist_intern->entries) {
    if (!filelist_intern_entry_is_main_file(entry)) {
      continue;
    }

    BLI_remlink(&filelist_intern->entries, entry);
    filelist_intern_entry_free(filelist, entry);
    removed_counter++;
  }

  MEM_SAFE_FREE(filelist_intern->filtered);
  return removed_counter;
}

static void filelist_cache_preview_runf(TaskPool *__restrict pool, void *taskdata)
{
  FileListEntryCache *cache = static_cast<FileListEntryCache *>(BLI_task_pool_user_data(pool));
  FileListEntryPreviewTaskData *preview_taskdata = static_cast<FileListEntryPreviewTaskData *>(
      taskdata);
  FileListEntryPreview *preview = preview_taskdata->preview;

  /* XXX #THB_SOURCE_IMAGE for "historic" reasons. The case of an undefined source should be
   * handled better. */
  ThumbSource source = THB_SOURCE_IMAGE;

  //  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;
  }

  IMB_thumb_path_lock(preview->filepath);
  /* 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. Do not create preview when file is offline. */
  ImBuf *imbuf = (preview->attributes & FILE_ATTR_OFFLINE) ?
                     IMB_thumb_read(preview->filepath, THB_LARGE) :
                     IMB_thumb_manage(preview->filepath, THB_LARGE, source);
  IMB_thumb_path_unlock(preview->filepath);
  if (imbuf) {
    preview->icon_id = BKE_icon_imbuf_create(imbuf);
  }

  /* Move ownership to the done queue. */
  preview_taskdata->preview = nullptr;

  BLI_thread_queue_push(cache->previews_done, preview);

  //  printf("%s: End (%d)...\n", __func__, threadid);
}

static void filelist_cache_preview_freef(TaskPool *__restrict /*pool*/, void *taskdata)
{
  FileListEntryPreviewTaskData *preview_taskdata = static_cast<FileListEntryPreviewTaskData *>(
      taskdata);

  /* In case the preview wasn't moved to the "done" queue yet. */
  if (preview_taskdata->preview) {
    MEM_freeN(preview_taskdata->preview);
  }

  MEM_freeN(preview_taskdata);
}

static void filelist_cache_preview_ensure_running(FileListEntryCache *cache)
{
  if (!cache->previews_pool) {
    cache->previews_pool = BLI_task_pool_create_background(cache, TASK_PRIORITY_LOW);
    cache->previews_done = BLI_thread_queue_init();
    cache->previews_todo_count = 0;

    IMB_thumb_locks_acquire();
  }
}

static void filelist_cache_previews_clear(FileListEntryCache *cache)
{
  if (cache->previews_pool) {
    BLI_task_pool_cancel(cache->previews_pool);

    FileListEntryPreview *preview;
    while ((preview = static_cast<FileListEntryPreview *>(
                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->icon_id) {
        BKE_icon_delete(preview->icon_id);
      }
      MEM_freeN(preview);
    }
    cache->previews_todo_count = 0;
  }
}

static void filelist_cache_previews_free(FileListEntryCache *cache)
{
  if (cache->previews_pool) {
    BLI_thread_queue_nowait(cache->previews_done);

    filelist_cache_previews_clear(cache);

    BLI_thread_queue_free(cache->previews_done);
    BLI_task_pool_free(cache->previews_pool);
    cache->previews_pool = nullptr;
    cache->previews_done = nullptr;
    cache->previews_todo_count = 0;

    IMB_thumb_locks_release();
  }

  cache->flags &= ~FLC_PREVIEWS_ACTIVE;
}

static void filelist_cache_previews_push(FileList *filelist, FileDirEntry *entry, const int index)
{
  FileListEntryCache *cache = &filelist->filelist_cache;

  BLI_assert(cache->flags & FLC_PREVIEWS_ACTIVE);

  if (entry->preview_icon_id) {
    return;
  }

  if (entry->flags & (FILE_ENTRY_INVALID_PREVIEW | FILE_ENTRY_PREVIEW_LOADING)) {
    return;
  }

  if (!(entry->typeflag & (FILE_TYPE_IMAGE | FILE_TYPE_MOVIE | FILE_TYPE_FTFONT |
                           FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP | FILE_TYPE_BLENDERLIB))) {
    return;
  }

  /* If we know this is an external ID without a preview, skip loading the preview. Can save quite
   * some time in heavy files, because otherwise for each missing preview and for each preview
   * reload, we'd reopen the .blend to look for the preview. */
  if ((entry->typeflag & FILE_TYPE_BLENDERLIB) &&
      (entry->flags & FILE_ENTRY_BLENDERLIB_NO_PREVIEW)) {
    return;
  }

  FileListInternEntry *intern_entry = filelist->filelist_intern.filtered[index];
  PreviewImage *preview_in_memory = intern_entry->local_data.preview_image;
  if (preview_in_memory && !BKE_previewimg_is_finished(preview_in_memory, ICON_SIZE_PREVIEW)) {
    /* Nothing to set yet. Wait for next call. */
    return;
  }

  filelist_cache_preview_ensure_running(cache);
  entry->flags |= FILE_ENTRY_PREVIEW_LOADING;

  FileListEntryPreview *preview = MEM_new<FileListEntryPreview>(__func__);
  preview->index = index;
  preview->flags = entry->typeflag;
  preview->attributes = entry->attributes;
  preview->icon_id = 0;

  if (preview_in_memory) {
    /* TODO(mano-wii): No need to use the thread API here. */
    BLI_assert(BKE_previewimg_is_finished(preview_in_memory, ICON_SIZE_PREVIEW));
    preview->filepath[0] = '\0';
    ImBuf *imbuf = BKE_previewimg_to_imbuf(preview_in_memory, ICON_SIZE_PREVIEW);
    if (imbuf) {
      preview->icon_id = BKE_icon_imbuf_create(imbuf);
    }
    BLI_thread_queue_push(cache->previews_done, preview);
  }
  else {
    if (entry->redirection_path) {
      BLI_strncpy(preview->filepath, entry->redirection_path, FILE_MAXDIR);
    }
    else {
      BLI_path_join(
          preview->filepath, sizeof(preview->filepath), filelist->filelist.root, entry->relpath);
    }
    // printf("%s: %d - %s\n", __func__, preview->index, preview->filepath);

    FileListEntryPreviewTaskData *preview_taskdata = MEM_new<FileListEntryPreviewTaskData>(
        __func__);
    preview_taskdata->preview = preview;
    BLI_task_pool_push(cache->previews_pool,
                       filelist_cache_preview_runf,
                       preview_taskdata,
                       true,
                       filelist_cache_preview_freef);
  }
  cache->previews_todo_count++;
}

static void filelist_cache_init(FileListEntryCache *cache, size_t cache_size)
{
  BLI_listbase_clear(&cache->cached_entries);

  cache->block_cursor = cache->block_start_index = cache->block_center_index =
      cache->block_end_index = 0;
  cache->block_entries = static_cast<FileDirEntry **>(
      MEM_mallocN(sizeof(*cache->block_entries) * cache_size, __func__));

  cache->misc_entries = BLI_ghash_ptr_new_ex(__func__, cache_size);
  cache->misc_entries_indices = static_cast<int *>(
      MEM_mallocN(sizeof(*cache->misc_entries_indices) * cache_size, __func__));
  copy_vn_i(cache->misc_entries_indices, cache_size, -1);
  cache->misc_cursor = 0;

  cache->uids = BLI_ghash_new_ex(
      BLI_ghashutil_inthash_p, BLI_ghashutil_intcmp, __func__, cache_size * 2);

  cache->size = cache_size;
  cache->flags = FLC_IS_INIT;

  cache->previews_todo_count = 0;
}

static void filelist_cache_free(FileListEntryCache *cache)
{
  if (!(cache->flags & FLC_IS_INIT)) {
    return;
  }

  filelist_cache_previews_free(cache);

  MEM_freeN(cache->block_entries);

  BLI_ghash_free(cache->misc_entries, nullptr, nullptr);
  MEM_freeN(cache->misc_entries_indices);

  BLI_ghash_free(cache->uids, nullptr, nullptr);

  LISTBASE_FOREACH_MUTABLE (FileDirEntry *, entry, &cache->cached_entries) {
    filelist_entry_free(entry);
  }
  BLI_listbase_clear(&cache->cached_entries);
}

static void filelist_cache_clear(FileListEntryCache *cache, size_t new_size)
{
  if (!(cache->flags & FLC_IS_INIT)) {
    return;
  }

  filelist_cache_previews_clear(cache);

  cache->block_cursor = cache->block_start_index = cache->block_center_index =
      cache->block_end_index = 0;
  if (new_size != cache->size) {
    cache->block_entries = static_cast<FileDirEntry **>(
        MEM_reallocN(cache->block_entries, sizeof(*cache->block_entries) * new_size));
  }

  BLI_ghash_clear_ex(cache->misc_entries, nullptr, nullptr, new_size);
  if (new_size != cache->size) {
    cache->misc_entries_indices = static_cast<int *>(MEM_reallocN(
        cache->misc_entries_indices, sizeof(*cache->misc_entries_indices) * new_size));
  }
  copy_vn_i(cache->misc_entries_indices, new_size, -1);

  BLI_ghash_clear_ex(cache->uids, nullptr, nullptr, new_size * 2);

  cache->size = new_size;

  LISTBASE_FOREACH_MUTABLE (FileDirEntry *, entry, &cache->cached_entries) {
    filelist_entry_free(entry);
  }
  BLI_listbase_clear(&cache->cached_entries);
}

FileList *filelist_new(short type)
{
  FileList *p = MEM_cnew<FileList>(__func__);

  filelist_cache_init(&p->filelist_cache, FILELIST_ENTRYCACHESIZE_DEFAULT);

  p->selection_state = BLI_ghash_new(BLI_ghashutil_inthash_p, BLI_ghashutil_intcmp, __func__);
  p->filelist.entries_num = FILEDIR_NBR_ENTRIES_UNSET;
  filelist_settype(p, type);

  return p;
}

void filelist_settype(FileList *filelist, short type)
{
  if (filelist->type == type) {
    return;
  }

  filelist->type = (eFileSelectType)type;
  filelist->tags = 0;
  filelist->indexer = &file_indexer_noop;
  switch (filelist->type) {
    case FILE_MAIN:
      filelist->check_dir_fn = filelist_checkdir_main;
      filelist->read_job_fn = filelist_readjob_main;
      filelist->prepare_filter_fn = nullptr;
      filelist->filter_fn = is_filtered_main;
      break;
    case FILE_LOADLIB:
      filelist->check_dir_fn = filelist_checkdir_lib;
      filelist->read_job_fn = filelist_readjob_lib;
      filelist->prepare_filter_fn = nullptr;
      filelist->filter_fn = is_filtered_lib;
      break;
    case FILE_ASSET_LIBRARY:
      filelist->check_dir_fn = filelist_checkdir_lib;
      filelist->read_job_fn = filelist_readjob_asset_library;
      filelist->prepare_filter_fn = prepare_filter_asset_library;
      filelist->filter_fn = is_filtered_asset_library;
      filelist->tags |= FILELIST_TAGS_USES_MAIN_DATA;
      break;
    case FILE_MAIN_ASSET:
      filelist->check_dir_fn = filelist_checkdir_main_assets;
      filelist->read_job_fn = filelist_readjob_main_assets;
      filelist->prepare_filter_fn = prepare_filter_asset_library;
      filelist->filter_fn = is_filtered_main_assets;
      filelist->tags |= FILELIST_TAGS_USES_MAIN_DATA | FILELIST_TAGS_NO_THREADS;
      break;
    default:
      filelist->check_dir_fn = filelist_checkdir_dir;
      filelist->read_job_fn = filelist_readjob_dir;
      filelist->prepare_filter_fn = nullptr;
      filelist->filter_fn = is_filtered_file;
      break;
  }

  filelist->flags |= FL_FORCE_RESET;
}

static void filelist_clear_asset_library(FileList *filelist)
{
  /* The AssetLibraryService owns the AssetLibrary pointer, so no need for us to free it. */
  filelist->asset_library = nullptr;
  file_delete_asset_catalog_filter_settings(&filelist->filter_data.asset_catalog_filter);
}

void filelist_clear_ex(struct FileList *filelist,
                       const bool do_asset_library,
                       const bool do_cache,
                       const bool do_selection)
{
  if (!filelist) {
    return;
  }

  filelist_tag_needs_filtering(filelist);

  if (do_cache) {
    filelist_cache_clear(&filelist->filelist_cache, filelist->filelist_cache.size);
  }

  filelist_intern_free(filelist);

  filelist_direntryarr_free(&filelist->filelist);

  if (do_selection && filelist->selection_state) {
    BLI_ghash_clear(filelist->selection_state, nullptr, nullptr);
  }

  if (do_asset_library) {
    filelist_clear_asset_library(filelist);
  }
}

static void filelist_clear_main_files(FileList *filelist,
                                      const bool do_asset_library,
                                      const bool do_cache,
                                      const bool do_selection)
{
  if (!filelist || !(filelist->tags & FILELIST_TAGS_USES_MAIN_DATA)) {
    return;
  }

  filelist_tag_needs_filtering(filelist);

  if (do_cache) {
    filelist_cache_clear(&filelist->filelist_cache, filelist->filelist_cache.size);
  }

  const int removed_files = filelist_intern_free_main_files(filelist);

  filelist->filelist.entries_num -= removed_files;
  filelist->filelist.entries_filtered_num = FILEDIR_NBR_ENTRIES_UNSET;
  BLI_assert(filelist->filelist.entries_num > FILEDIR_NBR_ENTRIES_UNSET);

  if (do_selection && filelist->selection_state) {
    BLI_ghash_clear(filelist->selection_state, nullptr, nullptr);
  }

  if (do_asset_library) {
    filelist_clear_asset_library(filelist);
  }
}

void filelist_clear(FileList *filelist)
{
  filelist_clear_ex(filelist, true, true, true);
}

void filelist_clear_from_reset_tag(FileList *filelist)
{
  /* Do a full clear if needed. */
  if (filelist->flags & FL_FORCE_RESET) {
    filelist_clear(filelist);
    return;
  }

  if (filelist->flags & FL_FORCE_RESET_MAIN_FILES) {
    filelist_clear_main_files(filelist, false, true, false);
    return;
  }
}

void filelist_free(struct FileList *filelist)
{
  if (!filelist) {
    printf("Attempting to delete empty filelist.\n");
    return;
  }

  /* No need to clear cache & selection_state, we free them anyway. */
  filelist_clear_ex(filelist, true, false, false);
  filelist_cache_free(&filelist->filelist_cache);

  if (filelist->selection_state) {
    BLI_ghash_free(filelist->selection_state, nullptr, nullptr);
    filelist->selection_state = nullptr;
  }

  MEM_SAFE_FREE(filelist->asset_library_ref);

  memset(&filelist->filter_data, 0, sizeof(filelist->filter_data));

  filelist->flags &= ~(FL_NEED_SORTING | FL_NEED_FILTERING);
}

AssetLibrary *filelist_asset_library(FileList *filelist)
{
  return reinterpret_cast<::AssetLibrary *>(filelist->asset_library);
}

void filelist_freelib(struct FileList *filelist)
{
  if (filelist->libfiledata) {
    BLO_blendhandle_close(filelist->libfiledata);
  }
  filelist->libfiledata = nullptr;
}

BlendHandle *filelist_lib(struct FileList *filelist)
{
  return filelist->libfiledata;
}

static const char *fileentry_uiname(const char *root, FileListInternEntry *entry, char *buff)
{
  if (entry->asset) {
    const StringRefNull asset_name = entry->asset->get_name();
    return BLI_strdupn(asset_name.c_str(), asset_name.size());
  }

  const char *relpath = entry->relpath;
  const eFileSel_File_Types typeflag = entry->typeflag;
  char *name = nullptr;

  if (typeflag & FILE_TYPE_FTFONT && !(typeflag & FILE_TYPE_BLENDERLIB)) {
    char abspath[FILE_MAX_LIBEXTRA];
    BLI_path_join(abspath, sizeof(abspath), root, relpath);
    name = BLF_display_name_from_file(abspath);
    if (name) {
      /* Allocated string, so no need to #BLI_strdup. */
      return name;
    }
  }

  if (typeflag & FILE_TYPE_BLENDERLIB) {
    char abspath[FILE_MAX_LIBEXTRA];
    char *group;

    BLI_path_join(abspath, sizeof(abspath), root, relpath);
    BLO_library_path_explode(abspath, buff, &group, &name);
    if (!name) {
      name = group;
    }
  }
  /* Depending on platforms, 'my_file.blend/..' might be viewed as dir or not... */
  if (!name) {
    if (typeflag & FILE_TYPE_DIR) {
      name = (char *)relpath;
    }
    else {
      name = (char *)BLI_path_basename(relpath);
    }
  }
  BLI_assert(name);

  return BLI_strdup(name);
}

const char *filelist_dir(struct FileList *filelist)
{
  return filelist->filelist.root;
}

bool filelist_is_dir(struct FileList *filelist, const char *path)
{
  return filelist->check_dir_fn(filelist, (char *)path, false);
}

void filelist_setdir(struct FileList *filelist, char *r_dir)
{
  const bool allow_invalid = filelist->asset_library_ref != nullptr;
  BLI_assert(strlen(r_dir) < FILE_MAX_LIBEXTRA);

  BLI_path_normalize_dir(BKE_main_blendfile_path_from_global(), r_dir, FILE_MAX_LIBEXTRA);
  const bool is_valid_path = filelist->check_dir_fn(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)) {
    BLI_strncpy(filelist->filelist.root, r_dir, sizeof(filelist->filelist.root));
    filelist->flags |= FL_FORCE_RESET;
  }
}

void filelist_setrecursion(struct FileList *filelist, const int recursion_level)
{
  if (filelist->max_recursion != recursion_level) {
    filelist->max_recursion = recursion_level;
    filelist->flags |= FL_FORCE_RESET;
  }
}

bool filelist_needs_force_reset(FileList *filelist)
{
  return (filelist->flags & (FL_FORCE_RESET | FL_FORCE_RESET_MAIN_FILES)) != 0;
}

void filelist_tag_force_reset(FileList *filelist)
{
  filelist->flags |= FL_FORCE_RESET;
}

void filelist_tag_force_reset_mainfiles(FileList *filelist)
{
  if (!(filelist->tags & FILELIST_TAGS_USES_MAIN_DATA)) {
    return;
  }
  filelist->flags |= FL_FORCE_RESET_MAIN_FILES;
}

bool filelist_is_ready(struct FileList *filelist)
{
  return (filelist->flags & FL_IS_READY) != 0;
}

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;
}

int filelist_files_ensure(FileList *filelist)
{
  if (!filelist_needs_force_reset(filelist) || !filelist_needs_reading(filelist)) {
    filelist_sort(filelist);
    filelist_filter(filelist);
  }

  return filelist->filelist.entries_filtered_num;
}

static FileDirEntry *filelist_file_create_entry(FileList *filelist, const int index)
{
  FileListInternEntry *entry = filelist->filelist_intern.filtered[index];
  FileListEntryCache *cache = &filelist->filelist_cache;
  FileDirEntry *ret;

  ret = MEM_cnew<FileDirEntry>(__func__);

  ret->size = uint64_t(entry->st.st_size);
  ret->time = int64_t(entry->st.st_mtime);

  ret->relpath = BLI_strdup(entry->relpath);
  if (entry->free_name) {
    ret->name = BLI_strdup(entry->name);
    ret->flags |= FILE_ENTRY_NAME_FREE;
  }
  else {
    ret->name = entry->name;
  }
  ret->uid = entry->uid;
  ret->blentype = entry->blentype;
  ret->typeflag = entry->typeflag;
  ret->attributes = entry->attributes;
  if (entry->redirection_path) {
    ret->redirection_path = BLI_strdup(entry->redirection_path);
  }
  ret->id = entry->local_data.id;
  ret->asset = reinterpret_cast<::AssetRepresentation *>(entry->asset);
  /* For some file types the preview is already available. */
  if (entry->local_data.preview_image &&
      BKE_previewimg_is_finished(entry->local_data.preview_image, ICON_SIZE_PREVIEW)) {
    ImBuf *ibuf = BKE_previewimg_to_imbuf(entry->local_data.preview_image, ICON_SIZE_PREVIEW);
    if (ibuf) {
      ret->preview_icon_id = BKE_icon_imbuf_create(ibuf);
    }
  }
  if (entry->blenderlib_has_no_preview) {
    ret->flags |= FILE_ENTRY_BLENDERLIB_NO_PREVIEW;
  }
  BLI_addtail(&cache->cached_entries, ret);
  return ret;
}

static void filelist_file_release_entry(FileList *filelist, FileDirEntry *entry)
{
  BLI_remlink(&filelist->filelist_cache.cached_entries, entry);
  filelist_entry_free(entry);
}

FileDirEntry *filelist_file_ex(struct FileList *filelist, const int index, const bool use_request)
{
  FileDirEntry *ret = nullptr, *old;
  FileListEntryCache *cache = &filelist->filelist_cache;
  const size_t cache_size = cache->size;
  int old_index;

  if ((index < 0) || (index >= filelist->filelist.entries_filtered_num)) {
    return ret;
  }

  if (index >= cache->block_start_index && index < cache->block_end_index) {
    const int idx = (index - cache->block_start_index + cache->block_cursor) % cache_size;
    return cache->block_entries[idx];
  }

  if ((ret = static_cast<FileDirEntry *>(
           BLI_ghash_lookup(cache->misc_entries, POINTER_FROM_INT(index))))) {
    return ret;
  }

  if (!use_request) {
    return nullptr;
  }

  //  printf("requesting file %d (not yet cached)\n", index);

  /* Else, we have to add new entry to 'misc' cache - and possibly make room for it first! */
  ret = filelist_file_create_entry(filelist, index);
  old_index = cache->misc_entries_indices[cache->misc_cursor];
  if ((old = static_cast<FileDirEntry *>(
           BLI_ghash_popkey(cache->misc_entries, POINTER_FROM_INT(old_index), nullptr)))) {
    BLI_ghash_remove(cache->uids, POINTER_FROM_UINT(old->uid), nullptr, nullptr);
    filelist_file_release_entry(filelist, old);
  }
  BLI_ghash_insert(cache->misc_entries, POINTER_FROM_INT(index), ret);
  BLI_ghash_insert(cache->uids, POINTER_FROM_UINT(ret->uid), ret);

  cache->misc_entries_indices[cache->misc_cursor] = index;
  cache->misc_cursor = (cache->misc_cursor + 1) % cache_size;

#if 0 /* Actually no, only block cached entries should have preview IMHO. */
  if (cache->previews_pool) {
    filelist_cache_previews_push(filelist, ret, index);
  }
#endif

  return ret;
}

FileDirEntry *filelist_file(struct FileList *filelist, int index)
{
  return filelist_file_ex(filelist, index, true);
}

int filelist_file_find_path(struct FileList *filelist, const char *filename)
{
  if (filelist->filelist.entries_filtered_num == FILEDIR_NBR_ENTRIES_UNSET) {
    return -1;
  }

  /* XXX TODO: Cache could probably use a ghash on paths too? Not really urgent though.
   * This is only used to find again renamed entry,
   * annoying but looks hairy to get rid of it currently. */

  for (int fidx = 0; fidx < filelist->filelist.entries_filtered_num; fidx++) {
    FileListInternEntry *entry = filelist->filelist_intern.filtered[fidx];
    if (STREQ(entry->relpath, filename)) {
      return fidx;
    }
  }

  return -1;
}

int filelist_file_find_id(const FileList *filelist, const ID *id)
{
  if (filelist->filelist.entries_filtered_num == FILEDIR_NBR_ENTRIES_UNSET) {
    return -1;
  }

  for (int fidx = 0; fidx < filelist->filelist.entries_filtered_num; fidx++) {
    FileListInternEntry *entry = filelist->filelist_intern.filtered[fidx];
    if (entry->local_data.id == id) {
      return fidx;
    }
  }

  return -1;
}

ID *filelist_file_get_id(const FileDirEntry *file)
{
  return file->id;
}

#define FILE_UID_UNSET 0

static FileUID filelist_uid_generate(FileList *filelist)
{
  /* Using an atomic operation to avoid having to lock thread...
   * Note that we do not really need this here currently, since there is a single listing thread,
   * but better remain consistent about threading! */
  return atomic_add_and_fetch_uint32(&filelist->filelist_intern.curr_uid, 1);
}

bool filelist_uid_is_set(const FileUID uid)
{
  FileUID unset_uid;
  filelist_uid_unset(&unset_uid);
  return unset_uid != uid;
}

void filelist_uid_unset(FileUID *r_uid)
{
  *r_uid = FILE_UID_UNSET;
}

void filelist_file_cache_slidingwindow_set(FileList *filelist, size_t window_size)
{
  /* Always keep it power of 2, in [256, 8192] range for now,
   * cache being app. twice bigger than requested window. */
  size_t size = 256;
  window_size *= 2;

  while (size < window_size && size < 8192) {
    size *= 2;
  }

  if (size != filelist->filelist_cache.size) {
    filelist_cache_clear(&filelist->filelist_cache, size);
  }
}

/* Helpers, low-level, they assume cursor + size <= cache_size */
static bool filelist_file_cache_block_create(FileList *filelist,
                                             const int start_index,
                                             const int size,
                                             int cursor)
{
  FileListEntryCache *cache = &filelist->filelist_cache;

  {
    int i, idx;

    for (i = 0, idx = start_index; i < size; i++, idx++, cursor++) {
      FileDirEntry *entry;

      /* That entry might have already been requested and stored in misc cache... */
      if ((entry = static_cast<FileDirEntry *>(BLI_ghash_popkey(
               cache->misc_entries, POINTER_FROM_INT(idx), nullptr))) == nullptr) {
        entry = filelist_file_create_entry(filelist, idx);
        BLI_ghash_insert(cache->uids, POINTER_FROM_UINT(entry->uid), entry);
      }
      cache->block_entries[cursor] = entry;
    }
    return true;
  }

  return false;
}

static void filelist_file_cache_block_release(struct FileList *filelist,
                                              const int size,
                                              int cursor)
{
  FileListEntryCache *cache = &filelist->filelist_cache;

  {
    int i;

    for (i = 0; i < size; i++, cursor++) {
      FileDirEntry *entry = cache->block_entries[cursor];
#if 0
      printf("%s: release cacheidx %d (%%p %%s)\n",
             __func__,
             cursor /*, cache->block_entries[cursor], cache->block_entries[cursor]->relpath*/);
#endif
      BLI_ghash_remove(cache->uids, POINTER_FROM_UINT(entry->uid), nullptr, nullptr);
      filelist_file_release_entry(filelist, entry);
#ifndef NDEBUG
      cache->block_entries[cursor] = nullptr;
#endif
    }
  }
}

bool filelist_file_cache_block(struct FileList *filelist, const int index)
{
  FileListEntryCache *cache = &filelist->filelist_cache;
  const size_t cache_size = cache->size;

  const int entries_num = filelist->filelist.entries_filtered_num;
  int start_index = max_ii(0, index - (cache_size / 2));
  int end_index = min_ii(entries_num, index + (cache_size / 2));
  int i;
  const bool full_refresh = (filelist->flags & FL_IS_READY) == 0;

  if ((index < 0) || (index >= entries_num)) {
    //      printf("Wrong index %d ([%d:%d])", index, 0, entries_num);
    return false;
  }

  /* Maximize cached range! */
  if ((end_index - start_index) < cache_size) {
    if (start_index == 0) {
      end_index = min_ii(entries_num, start_index + cache_size);
    }
    else if (end_index == entries_num) {
      start_index = max_ii(0, end_index - cache_size);
    }
  }

  BLI_assert((end_index - start_index) <= cache_size);

  //  printf("%s: [%d:%d] around index %d (current cache: [%d:%d])\n", __func__,
  //         start_index, end_index, index, cache->block_start_index, cache->block_end_index);

  /* If we have something to (re)cache... */
  if (full_refresh || (start_index != cache->block_start_index) ||
      (end_index != cache->block_end_index)) {
    if (full_refresh || (start_index >= cache->block_end_index) ||
        (end_index <= cache->block_start_index)) {
      int size1 = cache->block_end_index - cache->block_start_index;
      int size2 = 0;
      int idx1 = cache->block_cursor, idx2 = 0;

      //          printf("Full Recaching!\n");

      if (cache->flags & FLC_PREVIEWS_ACTIVE) {
        filelist_cache_previews_clear(cache);
      }

      if (idx1 + size1 > cache_size) {
        size2 = idx1 + size1 - cache_size;
        size1 -= size2;
        filelist_file_cache_block_release(filelist, size2, idx2);
      }
      filelist_file_cache_block_release(filelist, size1, idx1);

      cache->block_start_index = cache->block_end_index = cache->block_cursor = 0;

      /* New cached block does not overlap existing one, simple. */
      if (!filelist_file_cache_block_create(filelist, start_index, end_index - start_index, 0)) {
        return false;
      }

      cache->block_start_index = start_index;
      cache->block_end_index = end_index;
    }
    else {
      //          printf("Partial Recaching!\n");

      /* At this point, we know we keep part of currently cached entries, so update previews
       * if needed, and remove everything from working queue - we'll add all newly needed
       * entries at the end. */
      if (cache->flags & FLC_PREVIEWS_ACTIVE) {
        filelist_cache_previews_update(filelist);
        filelist_cache_previews_clear(cache);
      }

      //          printf("\tpreview cleaned up...\n");

      if (start_index > cache->block_start_index) {
        int size1 = start_index - cache->block_start_index;
        int size2 = 0;
        int idx1 = cache->block_cursor, idx2 = 0;

        //              printf("\tcache releasing: [%d:%d] (%d, %d)\n",
        //                     cache->block_start_index, cache->block_start_index + size1,
        //                     cache->block_cursor, size1);

        if (idx1 + size1 > cache_size) {
          size2 = idx1 + size1 - cache_size;
          size1 -= size2;
          filelist_file_cache_block_release(filelist, size2, idx2);
        }
        filelist_file_cache_block_release(filelist, size1, idx1);

        cache->block_cursor = (idx1 + size1 + size2) % cache_size;
        cache->block_start_index = start_index;
      }
      if (end_index < cache->block_end_index) {
        int size1 = cache->block_end_index - end_index;
        int size2 = 0;
        int idx1, idx2 = 0;

#if 0
        printf("\tcache releasing: [%d:%d] (%d)\n",
               cache->block_end_index - size1,
               cache->block_end_index,
               cache->block_cursor);
#endif

        idx1 = (cache->block_cursor + end_index - cache->block_start_index) % cache_size;
        if (idx1 + size1 > cache_size) {
          size2 = idx1 + size1 - cache_size;
          size1 -= size2;
          filelist_file_cache_block_release(filelist, size2, idx2);
        }
        filelist_file_cache_block_release(filelist, size1, idx1);

        cache->block_end_index = end_index;
      }

      //          printf("\tcache cleaned up...\n");

      if (start_index < cache->block_start_index) {
        /* Add (request) needed entries before already cached ones. */
        /* NOTE: We need some index black magic to wrap around (cycle)
         * inside our cache_size array... */
        int size1 = cache->block_start_index - start_index;
        int size2 = 0;
        int idx1, idx2;

        if (size1 > cache->block_cursor) {
          size2 = size1;
          size1 -= cache->block_cursor;
          size2 -= size1;
          idx2 = 0;
          idx1 = cache_size - size1;
        }
        else {
          idx1 = cache->block_cursor - size1;
        }

        if (size2) {
          if (!filelist_file_cache_block_create(filelist, start_index + size1, size2, idx2)) {
            return false;
          }
        }
        if (!filelist_file_cache_block_create(filelist, start_index, size1, idx1)) {
          return false;
        }

        cache->block_cursor = idx1;
        cache->block_start_index = start_index;
      }
      //          printf("\tstart-extended...\n");
      if (end_index > cache->block_end_index) {
        /* Add (request) needed entries after already cached ones. */
        /* NOTE: We need some index black magic to wrap around (cycle)
         * inside our cache_size array... */
        int size1 = end_index - cache->block_end_index;
        int size2 = 0;
        int idx1, idx2;

        idx1 = (cache->block_cursor + end_index - cache->block_start_index - size1) % cache_size;
        if ((idx1 + size1) > cache_size) {
          size2 = size1;
          size1 = cache_size - idx1;
          size2 -= size1;
          idx2 = 0;
        }

        if (size2) {
          if (!filelist_file_cache_block_create(filelist, end_index - size2, size2, idx2)) {
            return false;
          }
        }
        if (!filelist_file_cache_block_create(filelist, end_index - size1 - size2, size1, idx1)) {
          return false;
        }

        cache->block_end_index = end_index;
      }

      //          printf("\tend-extended...\n");
    }
  }
  else if ((cache->block_center_index != index) && (cache->flags & FLC_PREVIEWS_ACTIVE)) {
    /* We try to always preview visible entries first, so 'restart' preview background task. */
    filelist_cache_previews_update(filelist);
    filelist_cache_previews_clear(cache);
  }

  //  printf("Re-queueing previews...\n");

  if (cache->flags & FLC_PREVIEWS_ACTIVE) {
    /* Note we try to preview first images around given index - i.e. assumed visible ones. */
    int block_index = cache->block_cursor + (index - start_index);
    int offs_max = max_ii(end_index - index, index - start_index);
    for (i = 0; i <= offs_max; i++) {
      int offs = i;
      do {
        int offs_idx = index + offs;
        if (start_index <= offs_idx && offs_idx < end_index) {
          int offs_block_idx = (block_index + offs) % int(cache_size);
          filelist_cache_previews_push(filelist, cache->block_entries[offs_block_idx], offs_idx);
        }
      } while ((offs = -offs) < 0); /* Switch between negative and positive offset. */
    }
  }

  cache->block_center_index = index;

  //  printf("%s Finished!\n", __func__);

  return true;
}

void filelist_cache_previews_set(FileList *filelist, const bool use_previews)
{
  FileListEntryCache *cache = &filelist->filelist_cache;

  if (use_previews == ((cache->flags & FLC_PREVIEWS_ACTIVE) != 0)) {
    return;
  }
  /* Do not start preview work while listing, gives nasty flickering! */
  if (use_previews && (filelist->flags & FL_IS_READY)) {
    cache->flags |= FLC_PREVIEWS_ACTIVE;

    BLI_assert((cache->previews_pool == nullptr) && (cache->previews_done == nullptr) &&
               (cache->previews_todo_count == 0));

    //      printf("%s: Init Previews...\n", __func__);

    /* No need to populate preview queue here, filelist_file_cache_block() handles this. */
  }
  else {
    //      printf("%s: Clear Previews...\n", __func__);

    filelist_cache_previews_free(cache);
  }
}

bool filelist_cache_previews_update(FileList *filelist)
{
  FileListEntryCache *cache = &filelist->filelist_cache;
  TaskPool *pool = cache->previews_pool;
  bool changed = false;

  if (!pool) {
    return changed;
  }

  //  printf("%s: Update Previews...\n", __func__);

  while (!BLI_thread_queue_is_empty(cache->previews_done)) {
    FileListEntryPreview *preview = static_cast<FileListEntryPreview *>(
        BLI_thread_queue_pop(cache->previews_done));
    FileDirEntry *entry;

    /* Paranoid (should never happen currently
     * since we consume this queue from a single thread), but... */
    if (!preview) {
      continue;
    }
    /* entry might have been removed from cache in the mean time,
     * we do not want to cache it again here. */
    entry = filelist_file_ex(filelist, preview->index, false);

    // printf("%s: %d - %s - %p\n", __func__, preview->index, preview->filepath, preview->img);

    if (entry) {
      if (preview->icon_id) {
        /* The FILE_ENTRY_PREVIEW_LOADING flag should have prevented any other asynchronous
         * process from trying to generate the same preview icon. */
        BLI_assert_msg(!entry->preview_icon_id, "Preview icon should not have been generated yet");

        /* Move ownership over icon. */
        entry->preview_icon_id = preview->icon_id;
        preview->icon_id = 0;
        changed = true;
      }
      else {
        /* We want to avoid re-processing this entry continuously!
         * Note that, since entries only live in cache,
         * preview will be retried quite often anyway. */
        entry->flags |= FILE_ENTRY_INVALID_PREVIEW;
      }
      entry->flags &= ~FILE_ENTRY_PREVIEW_LOADING;
    }
    else {
      BKE_icon_delete(preview->icon_id);
    }

    MEM_freeN(preview);
    cache->previews_todo_count--;
  }

  return changed;
}

bool filelist_cache_previews_running(FileList *filelist)
{
  FileListEntryCache *cache = &filelist->filelist_cache;

  return (cache->previews_pool != nullptr);
}

bool filelist_cache_previews_done(FileList *filelist)
{
  FileListEntryCache *cache = &filelist->filelist_cache;
  if ((cache->flags & FLC_PREVIEWS_ACTIVE) == 0) {
    /* There are no previews. */
    return false;
  }

  return (cache->previews_pool == nullptr) || (cache->previews_done == nullptr) ||
         (cache->previews_todo_count == 0);
}

/* would recognize .blend as well */
static bool file_is_blend_backup(const char *str)
{
  const size_t a = strlen(str);
  size_t b = 7;
  bool retval = false;

  if (a == 0 || b >= a) {
    /* pass */
  }
  else {
    const char *loc;

    if (a > b + 1) {
      b++;
    }

    /* allow .blend1 .blend2 .blend32 */
    loc = BLI_strcasestr(str + a - b, ".blend");

    if (loc) {
      retval = true;
    }
  }

  return retval;
}

int ED_path_extension_type(const char *path)
{
  if (BLO_has_bfile_extension(path)) {
    return FILE_TYPE_BLENDER;
  }
  if (file_is_blend_backup(path)) {
    return FILE_TYPE_BLENDER_BACKUP;
  }
#ifdef __APPLE__
  if (BLI_path_extension_check_n(path,
                                 /* Application bundle */
                                 ".app",
                                 /* Safari in-progress/paused download */
                                 ".download",
                                 nullptr)) {
    return FILE_TYPE_BUNDLE;
  }
#endif
  if (BLI_path_extension_check(path, ".py")) {
    return FILE_TYPE_PYSCRIPT;
  }
  if (BLI_path_extension_check_n(path,
                                 ".txt",
                                 ".glsl",
                                 ".osl",
                                 ".data",
                                 ".pov",
                                 ".ini",
                                 ".mcr",
                                 ".inc",
                                 ".fountain",
                                 nullptr)) {
    return FILE_TYPE_TEXT;
  }
  if (BLI_path_extension_check_n(
          path, ".ttf", ".ttc", ".pfb", ".otf", ".otc", ".woff", ".woff2", nullptr)) {
    return FILE_TYPE_FTFONT;
  }
  if (BLI_path_extension_check(path, ".btx")) {
    return FILE_TYPE_BTX;
  }
  if (BLI_path_extension_check(path, ".dae")) {
    return FILE_TYPE_COLLADA;
  }
  if (BLI_path_extension_check(path, ".abc")) {
    return FILE_TYPE_ALEMBIC;
  }
  if (BLI_path_extension_check_n(path, ".usd", ".usda", ".usdc", nullptr)) {
    return FILE_TYPE_USD;
  }
  if (BLI_path_extension_check(path, ".vdb")) {
    return FILE_TYPE_VOLUME;
  }
  if (BLI_path_extension_check(path, ".zip")) {
    return FILE_TYPE_ARCHIVE;
  }
  if (BLI_path_extension_check_n(
          path, ".obj", ".mtl", ".3ds", ".fbx", ".glb", ".gltf", ".svg", ".stl", nullptr)) {
    return FILE_TYPE_OBJECT_IO;
  }
  if (BLI_path_extension_check_array(path, imb_ext_image)) {
    return FILE_TYPE_IMAGE;
  }
  if (BLI_path_extension_check(path, ".ogg")) {
    if (IMB_isanim(path)) {
      return FILE_TYPE_MOVIE;
    }
    return FILE_TYPE_SOUND;
  }
  if (BLI_path_extension_check_array(path, imb_ext_movie)) {
    return FILE_TYPE_MOVIE;
  }
  if (BLI_path_extension_check_array(path, imb_ext_audio)) {
    return FILE_TYPE_SOUND;
  }
  return 0;
}

int ED_file_extension_icon(const char *path)
{
  const int type = ED_path_extension_type(path);

  switch (type) {
    case FILE_TYPE_BLENDER:
      return ICON_FILE_BLEND;
    case FILE_TYPE_BLENDER_BACKUP:
      return ICON_FILE_BACKUP;
    case FILE_TYPE_IMAGE:
      return ICON_FILE_IMAGE;
    case FILE_TYPE_MOVIE:
      return ICON_FILE_MOVIE;
    case FILE_TYPE_PYSCRIPT:
      return ICON_FILE_SCRIPT;
    case FILE_TYPE_SOUND:
      return ICON_FILE_SOUND;
    case FILE_TYPE_FTFONT:
      return ICON_FILE_FONT;
    case FILE_TYPE_BTX:
      return ICON_FILE_BLANK;
    case FILE_TYPE_COLLADA:
    case FILE_TYPE_ALEMBIC:
    case FILE_TYPE_OBJECT_IO:
      return ICON_FILE_3D;
    case FILE_TYPE_TEXT:
      return ICON_FILE_TEXT;
    case FILE_TYPE_ARCHIVE:
      return ICON_FILE_ARCHIVE;
    case FILE_TYPE_VOLUME:
      return ICON_FILE_VOLUME;
    default:
      return ICON_FILE_BLANK;
  }
}

int filelist_needs_reading(FileList *filelist)
{
  return (filelist->filelist.entries_num == FILEDIR_NBR_ENTRIES_UNSET) ||
         filelist_needs_force_reset(filelist);
}

uint filelist_entry_select_set(const FileList *filelist,
                               const FileDirEntry *entry,
                               FileSelType select,
                               uint flag,
                               FileCheckType check)
{
  /* Default nullptr pointer if not found is fine here! */
  void **es_p = BLI_ghash_lookup_p(filelist->selection_state, POINTER_FROM_UINT(entry->uid));
  uint entry_flag = es_p ? POINTER_AS_UINT(*es_p) : 0;
  const uint org_entry_flag = entry_flag;

  BLI_assert(entry);
  BLI_assert(ELEM(check, CHECK_DIRS, CHECK_FILES, CHECK_ALL));

  if ((check == CHECK_ALL) || ((check == CHECK_DIRS) && (entry->typeflag & FILE_TYPE_DIR)) ||
      ((check == CHECK_FILES) && !(entry->typeflag & FILE_TYPE_DIR))) {
    switch (select) {
      case FILE_SEL_REMOVE:
        entry_flag &= ~flag;
        break;
      case FILE_SEL_ADD:
        entry_flag |= flag;
        break;
      case FILE_SEL_TOGGLE:
        entry_flag ^= flag;
        break;
    }
  }

  if (entry_flag != org_entry_flag) {
    if (es_p) {
      if (entry_flag) {
        *es_p = POINTER_FROM_UINT(entry_flag);
      }
      else {
        BLI_ghash_remove(
            filelist->selection_state, POINTER_FROM_UINT(entry->uid), nullptr, nullptr);
      }
    }
    else if (entry_flag) {
      BLI_ghash_insert(
          filelist->selection_state, POINTER_FROM_UINT(entry->uid), POINTER_FROM_UINT(entry_flag));
    }
  }

  return entry_flag;
}

void filelist_entry_select_index_set(
    FileList *filelist, const int index, FileSelType select, uint flag, FileCheckType check)
{
  FileDirEntry *entry = filelist_file(filelist, index);

  if (entry) {
    filelist_entry_select_set(filelist, entry, select, flag, check);
  }
}

void filelist_entries_select_index_range_set(
    FileList *filelist, FileSelection *sel, FileSelType select, uint flag, FileCheckType check)
{
  /* select all valid files between first and last indicated */
  if ((sel->first >= 0) && (sel->first < filelist->filelist.entries_filtered_num) &&
      (sel->last >= 0) && (sel->last < filelist->filelist.entries_filtered_num)) {
    int current_file;
    for (current_file = sel->first; current_file <= sel->last; current_file++) {
      filelist_entry_select_index_set(filelist, current_file, select, flag, check);
    }
  }
}

uint filelist_entry_select_get(FileList *filelist, FileDirEntry *entry, FileCheckType check)
{
  BLI_assert(entry);
  BLI_assert(ELEM(check, CHECK_DIRS, CHECK_FILES, CHECK_ALL));

  if ((check == CHECK_ALL) || ((check == CHECK_DIRS) && (entry->typeflag & FILE_TYPE_DIR)) ||
      ((check == CHECK_FILES) && !(entry->typeflag & FILE_TYPE_DIR))) {
    /* Default nullptr pointer if not found is fine here! */
    return POINTER_AS_UINT(
        BLI_ghash_lookup(filelist->selection_state, POINTER_FROM_UINT(entry->uid)));
  }

  return 0;
}

uint filelist_entry_select_index_get(FileList *filelist, const int index, FileCheckType check)
{
  FileDirEntry *entry = filelist_file(filelist, index);

  if (entry) {
    return filelist_entry_select_get(filelist, entry, check);
  }

  return 0;
}

bool filelist_entry_is_selected(FileList *filelist, const int index)
{
  BLI_assert(index >= 0 && index < filelist->filelist.entries_filtered_num);
  FileListInternEntry *intern_entry = filelist->filelist_intern.filtered[index];

  /* BLI_ghash_lookup returns nullptr if not found, which gets mapped to 0, which gets mapped to
   * "not selected". */
  const uint selection_state = POINTER_AS_UINT(
      BLI_ghash_lookup(filelist->selection_state, POINTER_FROM_UINT(intern_entry->uid)));

  return selection_state != 0;
}

void filelist_entry_parent_select_set(FileList *filelist,
                                      FileSelType select,
                                      uint flag,
                                      FileCheckType check)
{
  if ((filelist->filter_data.flags & FLF_HIDE_PARENT) == 0) {
    filelist_entry_select_index_set(filelist, 0, select, flag, check);
  }
}

bool filelist_islibrary(struct FileList *filelist, char *dir, char **r_group)
{
  return BLO_library_path_explode(filelist->filelist.root, dir, r_group, nullptr);
}

static int groupname_to_code(const char *group)
{
  char buf[BLO_GROUP_MAX];
  char *lslash;

  BLI_assert(group);

  BLI_strncpy(buf, group, sizeof(buf));
  lslash = (char *)BLI_path_slash_rfind(buf);
  if (lslash) {
    lslash[0] = '\0';
  }

  return buf[0] ? BKE_idtype_idcode_from_name(buf) : 0;
}

static uint64_t groupname_to_filter_id(const char *group)
{
  int id_code = groupname_to_code(group);

  return BKE_idtype_idcode_to_idfilter(id_code);
}

/**
 * From here, we are in 'Job Context',
 * i.e. have to be careful about sharing stuff between background working thread.
 * and main one (used by UI among other things).
 */
struct TodoDir {
  int level;
  char *dir;
};

static int filelist_readjob_list_dir(const char *root,
                                     ListBase *entries,
                                     const char *filter_glob,
                                     const bool do_lib,
                                     const char *main_name,
                                     const bool skip_currpar)
{
  struct direntry *files;
  int entries_num = 0;
  /* Full path of the item. */
  char full_path[FILE_MAX];

  const int files_num = BLI_filelist_dir_contents(root, &files);
  if (files) {
    int i = files_num;
    while (i--) {
      FileListInternEntry *entry;

      if (skip_currpar && FILENAME_IS_CURRPAR(files[i].relname)) {
        continue;
      }

      entry = MEM_cnew<FileListInternEntry>(__func__);
      entry->relpath = static_cast<char *>(MEM_dupallocN(files[i].relname));
      entry->st = files[i].s;

      BLI_path_join(full_path, FILE_MAX, root, entry->relpath);
      char *target = full_path;

      /* Set initial file type and attributes. */
      entry->attributes = BLI_file_attributes(full_path);
      if (S_ISDIR(files[i].s.st_mode)
#ifdef __APPLE__
          && !(ED_path_extension_type(full_path) & FILE_TYPE_BUNDLE)
#endif
      ) {
        entry->typeflag = FILE_TYPE_DIR;
      }

      /* Is this a file that points to another file? */
      if (entry->attributes & FILE_ATTR_ALIAS) {
        entry->redirection_path = MEM_cnew_array<char>(FILE_MAXDIR, __func__);
        if (BLI_file_alias_target(full_path, entry->redirection_path)) {
          if (BLI_is_dir(entry->redirection_path)) {
            entry->typeflag = FILE_TYPE_DIR;
            BLI_path_slash_ensure(entry->redirection_path, FILE_MAXDIR);
          }
          else {
            entry->typeflag = (eFileSel_File_Types)ED_path_extension_type(entry->redirection_path);
          }
          target = entry->redirection_path;
#ifdef WIN32
          /* On Windows don't show `.lnk` extension for valid shortcuts. */
          BLI_path_extension_replace(entry->relpath, FILE_MAXDIR, "");
#endif
        }
        else {
          MEM_freeN(entry->redirection_path);
          entry->redirection_path = nullptr;
          entry->attributes |= FILE_ATTR_HIDDEN;
        }
      }

      if (!(entry->typeflag & FILE_TYPE_DIR)) {
        if (do_lib && BLO_has_bfile_extension(target)) {
          /* If we are considering .blend files as libraries, promote them to directory status. */
          entry->typeflag = FILE_TYPE_BLENDER;
          /* prevent current file being used as acceptable dir */
          if (BLI_path_cmp(main_name, target) != 0) {
            entry->typeflag |= FILE_TYPE_DIR;
          }
        }
        else {
          entry->typeflag = (eFileSel_File_Types)ED_path_extension_type(target);
          if (filter_glob[0] && BLI_path_extension_check_glob(target, filter_glob)) {
            entry->typeflag |= FILE_TYPE_OPERATOR;
          }
        }
      }

#ifndef WIN32
      /* Set linux-style dot files hidden too. */
      if (is_hidden_dot_filename(entry->relpath, entry)) {
        entry->attributes |= FILE_ATTR_HIDDEN;
      }
#endif

      BLI_addtail(entries, entry);
      entries_num++;
    }
    BLI_filelist_free(files, files_num);
  }
  return entries_num;
}

enum ListLibOptions {
  LIST_LIB_OPTION_NONE = 0,

  /* Will read both the groups + actual ids from the library. Reduces the amount of times that
   * a library needs to be opened. */
  LIST_LIB_RECURSIVE = (1 << 0),

  /* Will only list assets. */
  LIST_LIB_ASSETS_ONLY = (1 << 1),

  /* Add given root as result. */
  LIST_LIB_ADD_PARENT = (1 << 2),
};
ENUM_OPERATORS(ListLibOptions, LIST_LIB_ADD_PARENT);

static FileListInternEntry *filelist_readjob_list_lib_group_create(const int idcode,
                                                                   const char *group_name)
{
  FileListInternEntry *entry = MEM_cnew<FileListInternEntry>(__func__);
  entry->relpath = BLI_strdup(group_name);
  entry->typeflag |= FILE_TYPE_BLENDERLIB | FILE_TYPE_DIR;
  entry->blentype = idcode;
  return entry;
}

/**
 * \warning: This "steals" the asset metadata from \a datablock_info. Not great design but fixing
 *           this requires redesigning things on the caller side for proper ownership management.
 */
static void filelist_readjob_list_lib_add_datablock(FileList *filelist,
                                                    ListBase *entries,
                                                    BLODataBlockInfo *datablock_info,
                                                    const bool prefix_relpath_with_group_name,
                                                    const int idcode,
                                                    const char *group_name)
{
  FileListInternEntry *entry = MEM_cnew<FileListInternEntry>(__func__);
  if (prefix_relpath_with_group_name) {
    entry->relpath = BLI_sprintfN("%s/%s", group_name, datablock_info->name);
  }
  else {
    entry->relpath = BLI_strdup(datablock_info->name);
  }
  entry->typeflag |= FILE_TYPE_BLENDERLIB;
  if (datablock_info) {
    entry->blenderlib_has_no_preview = datablock_info->no_preview_found;

    if (datablock_info->asset_data) {
      entry->typeflag |= FILE_TYPE_ASSET;

      if (filelist->asset_library) {
        /** XXX Moving out the asset metadata like this isn't great. */
        std::unique_ptr metadata = BKE_asset_metadata_move_to_unique_ptr(
            datablock_info->asset_data);
        BKE_asset_metadata_free(&datablock_info->asset_data);

        entry->asset = &filelist->asset_library->add_external_asset(datablock_info->name,
                                                                    std::move(metadata));
      }
    }
  }
  entry->blentype = idcode;
  BLI_addtail(entries, entry);
}

static void filelist_readjob_list_lib_add_datablocks(FileList *filelist,
                                                     ListBase *entries,
                                                     LinkNode *datablock_infos,
                                                     const bool prefix_relpath_with_group_name,
                                                     const int idcode,
                                                     const char *group_name)
{
  for (LinkNode *ln = datablock_infos; ln; ln = ln->next) {
    struct BLODataBlockInfo *datablock_info = static_cast<BLODataBlockInfo *>(ln->link);
    filelist_readjob_list_lib_add_datablock(
        filelist, entries, datablock_info, prefix_relpath_with_group_name, idcode, group_name);
  }
}

static void filelist_readjob_list_lib_add_from_indexer_entries(
    FileList *filelist,
    ListBase *entries,
    const FileIndexerEntries *indexer_entries,
    const bool prefix_relpath_with_group_name)
{
  for (const LinkNode *ln = indexer_entries->entries; ln; ln = ln->next) {
    FileIndexerEntry *indexer_entry = static_cast<FileIndexerEntry *>(ln->link);
    const char *group_name = BKE_idtype_idcode_to_name(indexer_entry->idcode);
    filelist_readjob_list_lib_add_datablock(filelist,
                                            entries,
                                            &indexer_entry->datablock_info,
                                            prefix_relpath_with_group_name,
                                            indexer_entry->idcode,
                                            group_name);
  }
}

static FileListInternEntry *filelist_readjob_list_lib_navigate_to_parent_entry_create(void)
{
  FileListInternEntry *entry = MEM_cnew<FileListInternEntry>(__func__);
  entry->relpath = BLI_strdup(FILENAME_PARENT);
  entry->typeflag |= (FILE_TYPE_BLENDERLIB | FILE_TYPE_DIR);
  return entry;
}

/**
 * Structure to keep the file indexer and its user data together.
 */
typedef struct FileIndexer {
  const FileIndexerType *callbacks;

  /**
   * User data. Contains the result of `callbacks.init_user_data`.
   */
  void *user_data;
} FileIndexer;

static int filelist_readjob_list_lib_populate_from_index(FileList *filelist,
                                                         ListBase *entries,
                                                         const ListLibOptions options,
                                                         const int read_from_index,
                                                         const FileIndexerEntries *indexer_entries)
{
  int navigate_to_parent_len = 0;
  if (options & LIST_LIB_ADD_PARENT) {
    FileListInternEntry *entry = filelist_readjob_list_lib_navigate_to_parent_entry_create();
    BLI_addtail(entries, entry);
    navigate_to_parent_len = 1;
  }

  filelist_readjob_list_lib_add_from_indexer_entries(filelist, entries, indexer_entries, true);
  return read_from_index + navigate_to_parent_len;
}

static int filelist_readjob_list_lib(FileList *filelist,
                                     const char *root,
                                     ListBase *entries,
                                     const ListLibOptions options,
                                     FileIndexer *indexer_runtime)
{
  BLI_assert(indexer_runtime);

  char dir[FILE_MAX_LIBEXTRA], *group;

  struct BlendHandle *libfiledata = nullptr;

  /* Check if the given root is actually a library. All folders are passed to
   * `filelist_readjob_list_lib` and based on the number of found entries `filelist_readjob_do`
   * will do a dir listing only when this function does not return any entries. */
  /* TODO(jbakker): We should consider introducing its own function to detect if it is a lib and
   * call it directly from `filelist_readjob_do` to increase readability. */
  const bool is_lib = BLO_library_path_explode(root, dir, &group, nullptr);
  if (!is_lib) {
    return 0;
  }

  const bool group_came_from_path = group != nullptr;

  /* Try read from indexer_runtime. */
  /* Indexing returns all entries in a blend file. We should ignore the index when listing a group
   * inside a blend file, so the `entries` isn't filled with undesired entries.
   * This happens when linking or appending data-blocks, where you can navigate into a group (ie
   * Materials/Objects) where you only want to work with partial indexes.
   *
   * Adding support for partial reading/updating indexes would increase the complexity.
   */
  const bool use_indexer = !group_came_from_path;
  FileIndexerEntries indexer_entries = {nullptr};
  if (use_indexer) {
    int read_from_index = 0;
    eFileIndexerResult indexer_result = indexer_runtime->callbacks->read_index(
        dir, &indexer_entries, &read_from_index, indexer_runtime->user_data);
    if (indexer_result == FILE_INDEXER_ENTRIES_LOADED) {
      int entries_read = filelist_readjob_list_lib_populate_from_index(
          filelist, entries, options, read_from_index, &indexer_entries);
      ED_file_indexer_entries_clear(&indexer_entries);
      return entries_read;
    }
  }

  /* Open the library file. */
  BlendFileReadReport bf_reports{};
  libfiledata = BLO_blendhandle_from_file(dir, &bf_reports);
  if (libfiledata == nullptr) {
    return 0;
  }

  /* Add current parent when requested. */
  /* Is the navigate to previous level added to the list of entries. When added the return value
   * should be increased to match the actual number of entries added. It is introduced to keep
   * the code clean and readable and not counting in a single variable. */
  int navigate_to_parent_len = 0;
  if (options & LIST_LIB_ADD_PARENT) {
    FileListInternEntry *entry = filelist_readjob_list_lib_navigate_to_parent_entry_create();
    BLI_addtail(entries, entry);
    navigate_to_parent_len = 1;
  }

  int group_len = 0;
  int datablock_len = 0;
  if (group_came_from_path) {
    const int idcode = groupname_to_code(group);
    LinkNode *datablock_infos = BLO_blendhandle_get_datablock_info(
        libfiledata, idcode, options & LIST_LIB_ASSETS_ONLY, &datablock_len);
    filelist_readjob_list_lib_add_datablocks(
        filelist, entries, datablock_infos, false, idcode, group);
    BLI_linklist_freeN(datablock_infos);
  }
  else {
    LinkNode *groups = BLO_blendhandle_get_linkable_groups(libfiledata);
    group_len = BLI_linklist_count(groups);

    for (LinkNode *ln = groups; ln; ln = ln->next) {
      const char *group_name = static_cast<char *>(ln->link);
      const int idcode = groupname_to_code(group_name);
      FileListInternEntry *group_entry = filelist_readjob_list_lib_group_create(idcode,
                                                                                group_name);
      BLI_addtail(entries, group_entry);

      if (options & LIST_LIB_RECURSIVE) {
        int group_datablock_len;
        LinkNode *group_datablock_infos = BLO_blendhandle_get_datablock_info(
            libfiledata, idcode, options & LIST_LIB_ASSETS_ONLY, &group_datablock_len);
        filelist_readjob_list_lib_add_datablocks(
            filelist, entries, group_datablock_infos, true, idcode, group_name);
        if (use_indexer) {
          ED_file_indexer_entries_extend_from_datablock_infos(
              &indexer_entries, group_datablock_infos, idcode);
        }
        BLI_linklist_freeN(group_datablock_infos);
        datablock_len += group_datablock_len;
      }
    }

    BLI_linklist_freeN(groups);
  }

  BLO_blendhandle_close(libfiledata);

  /* Update the index. */
  if (use_indexer) {
    indexer_runtime->callbacks->update_index(dir, &indexer_entries, indexer_runtime->user_data);
    ED_file_indexer_entries_clear(&indexer_entries);
  }

  /* Return the number of items added to entries. */
  int added_entries_len = group_len + datablock_len + navigate_to_parent_len;
  return added_entries_len;
}

#if 0
/* Kept for reference here, in case we want to add back that feature later.
 * We do not need it currently. */
/* Code ***NOT*** updated for job stuff! */
static void filelist_readjob_main_recursive(Main *bmain, FileList *filelist)
{
  ID *id;
  FileDirEntry *files, *firstlib = nullptr;
  ListBase *lb;
  int a, fake, idcode, ok, totlib, totbl;

  // filelist->type = FILE_MAIN; /* XXX TODO: add modes to file-browser */

  BLI_assert(filelist->filelist.entries == nullptr);

  if (filelist->filelist.root[0] == '/') {
    filelist->filelist.root[0] = '\0';
  }

  if (filelist->filelist.root[0]) {
    idcode = groupname_to_code(filelist->filelist.root);
    if (idcode == 0) {
      filelist->filelist.root[0] = '\0';
    }
  }

  if (filelist->dir[0] == 0) {
    /* make directories */
#  ifdef WITH_FREESTYLE
    filelist->filelist.entries_num = 27;
#  else
    filelist->filelist.entries_num = 26;
#  endif
    filelist_resize(filelist, filelist->filelist.entries_num);

    for (a = 0; a < filelist->filelist.entries_num; a++) {
      filelist->filelist.entries[a].typeflag |= FILE_TYPE_DIR;
    }

    filelist->filelist.entries[0].entry->relpath = BLI_strdup(FILENAME_PARENT);
    filelist->filelist.entries[1].entry->relpath = BLI_strdup("Scene");
    filelist->filelist.entries[2].entry->relpath = BLI_strdup("Object");
    filelist->filelist.entries[3].entry->relpath = BLI_strdup("Mesh");
    filelist->filelist.entries[4].entry->relpath = BLI_strdup("Curve");
    filelist->filelist.entries[5].entry->relpath = BLI_strdup("Metaball");
    filelist->filelist.entries[6].entry->relpath = BLI_strdup("Material");
    filelist->filelist.entries[7].entry->relpath = BLI_strdup("Texture");
    filelist->filelist.entries[8].entry->relpath = BLI_strdup("Image");
    filelist->filelist.entries[9].entry->relpath = BLI_strdup("Ika");
    filelist->filelist.entries[10].entry->relpath = BLI_strdup("Wave");
    filelist->filelist.entries[11].entry->relpath = BLI_strdup("Lattice");
    filelist->filelist.entries[12].entry->relpath = BLI_strdup("Light");
    filelist->filelist.entries[13].entry->relpath = BLI_strdup("Camera");
    filelist->filelist.entries[14].entry->relpath = BLI_strdup("Ipo");
    filelist->filelist.entries[15].entry->relpath = BLI_strdup("World");
    filelist->filelist.entries[16].entry->relpath = BLI_strdup("Screen");
    filelist->filelist.entries[17].entry->relpath = BLI_strdup("VFont");
    filelist->filelist.entries[18].entry->relpath = BLI_strdup("Text");
    filelist->filelist.entries[19].entry->relpath = BLI_strdup("Armature");
    filelist->filelist.entries[20].entry->relpath = BLI_strdup("Action");
    filelist->filelist.entries[21].entry->relpath = BLI_strdup("NodeTree");
    filelist->filelist.entries[22].entry->relpath = BLI_strdup("Speaker");
    filelist->filelist.entries[23].entry->relpath = BLI_strdup("Curves");
    filelist->filelist.entries[24].entry->relpath = BLI_strdup("Point Cloud");
    filelist->filelist.entries[25].entry->relpath = BLI_strdup("Volume");
#  ifdef WITH_FREESTYLE
    filelist->filelist.entries[26].entry->relpath = BLI_strdup("FreestyleLineStyle");
#  endif
  }
  else {
    /* make files */
    idcode = groupname_to_code(filelist->filelist.root);

    lb = which_libbase(bmain, idcode);
    if (lb == nullptr) {
      return;
    }

    filelist->filelist.entries_num = 0;
    for (id = lb->first; id; id = id->next) {
      if (!(filelist->filter_data.flags & FLF_HIDE_DOT) || id->name[2] != '.') {
        filelist->filelist.entries_num++;
      }
    }

    /* XXX TODO: if data-browse or append/link #FLF_HIDE_PARENT has to be set. */
    if (!(filelist->filter_data.flags & FLF_HIDE_PARENT)) {
      filelist->filelist.entries_num++;
    }

    if (filelist->filelist.entries_num > 0) {
      filelist_resize(filelist, filelist->filelist.entries_num);
    }

    files = filelist->filelist.entries;

    if (!(filelist->filter_data.flags & FLF_HIDE_PARENT)) {
      files->entry->relpath = BLI_strdup(FILENAME_PARENT);
      files->typeflag |= FILE_TYPE_DIR;

      files++;
    }

    totlib = totbl = 0;
    for (id = lb->first; id; id = id->next) {
      ok = 1;
      if (ok) {
        if (!(filelist->filter_data.flags & FLF_HIDE_DOT) || id->name[2] != '.') {
          if (!ID_IS_LINKED(id)) {
            files->entry->relpath = BLI_strdup(id->name + 2);
          }
          else {
            char relname[FILE_MAX + (MAX_ID_NAME - 2) + 3];
            BLI_snprintf(relname, sizeof(relname), "%s | %s", id->lib->filepath, id->name + 2);
            files->entry->relpath = BLI_strdup(relname);
          }
//                  files->type |= S_IFREG;
#  if 0 /* XXX TODO: show the selection status of the objects. */
          if (!filelist->has_func) { /* F4 DATA BROWSE */
            if (idcode == ID_OB) {
              if ( ((Object *)id)->flag & SELECT) {
                files->entry->selflag |= FILE_SEL_SELECTED;
              }
            }
            else if (idcode == ID_SCE) {
              if ( ((Scene *)id)->r.scemode & R_BG_RENDER) {
                files->entry->selflag |= FILE_SEL_SELECTED;
              }
            }
          }
#  endif
          //                  files->entry->nr = totbl + 1;
          files->entry->poin = id;
          fake = id->flag & LIB_FAKEUSER;
          if (ELEM(idcode, ID_MA, ID_TE, ID_LA, ID_WO, ID_IM)) {
            files->typeflag |= FILE_TYPE_IMAGE;
          }
#  if 0
          if (id->lib && fake) {
            BLI_snprintf(files->extra, sizeof(files->entry->extra), "LF %d", id->us);
          }
          else if (id->lib) {
            BLI_snprintf(files->extra, sizeof(files->entry->extra), "L    %d", id->us);
          }
          else if (fake) {
            BLI_snprintf(files->extra, sizeof(files->entry->extra), "F    %d", id->us);
          }
          else {
            BLI_snprintf(files->extra, sizeof(files->entry->extra), "      %d", id->us);
          }
#  endif

          if (id->lib) {
            if (totlib == 0) {
              firstlib = files;
            }
            totlib++;
          }

          files++;
        }
        totbl++;
      }
    }

    /* only qsort of library blocks */
    if (totlib > 1) {
      qsort(firstlib, totlib, sizeof(*files), compare_name);
    }
  }
}
#endif

struct FileListReadJob {
  ThreadMutex lock;
  char main_name[FILE_MAX];
  Main *current_main;
  FileList *filelist;
  /** Set to request a partial read that only adds files representing #Main data (IDs). Used when
   * #Main may have received changes of interest (e.g. asset removed or renamed). */
  bool only_main_data;

  /** Shallow copy of #filelist for thread-safe access.
   *
   * The job system calls #filelist_readjob_update which moves any read file from #tmp_filelist
   * into #filelist in a thread-safe way.
   *
   * #tmp_filelist also keeps an `AssetLibrary *` so that it can be loaded in the same thread,
   * and moved to #filelist once all categories are loaded.
   *
   * NOTE: #tmp_filelist is freed in #filelist_readjob_free, so any copied pointers need to be
   * set to nullptr to avoid double-freeing them. */
  FileList *tmp_filelist;
};

static void filelist_readjob_append_entries(FileListReadJob *job_params,
                                            ListBase *from_entries,
                                            int from_entries_num,
                                            bool *do_update)
{
  BLI_assert(BLI_listbase_count(from_entries) == from_entries_num);
  if (from_entries_num <= 0) {
    *do_update = false;
    return;
  }

  FileList *filelist = job_params->tmp_filelist; /* Use the thread-safe filelist queue. */
  BLI_mutex_lock(&job_params->lock);
  BLI_movelisttolist(&filelist->filelist.entries, from_entries);
  filelist->filelist.entries_num += from_entries_num;
  BLI_mutex_unlock(&job_params->lock);

  *do_update = true;
}

static bool filelist_readjob_should_recurse_into_entry(const int max_recursion,
                                                       const bool is_lib,
                                                       const int current_recursion_level,
                                                       FileListInternEntry *entry)
{
  if (max_recursion == 0) {
    /* Recursive loading is disabled. */
    return false;
  }
  if (!is_lib && current_recursion_level > max_recursion) {
    /* No more levels of recursion left. */
    return false;
  }
  /* Show entries when recursion is set to `Blend file` even when `current_recursion_level`
   * exceeds `max_recursion`. */
  if (!is_lib && (current_recursion_level >= max_recursion) &&
      ((entry->typeflag & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) == 0)) {
    return false;
  }
  if (entry->typeflag & FILE_TYPE_BLENDERLIB) {
    /* Libraries are already loaded recursively when recursive loaded is used. No need to add
     * them another time. This loading is done with the `LIST_LIB_RECURSIVE` option. */
    return false;
  }
  if (!(entry->typeflag & FILE_TYPE_DIR)) {
    /* Cannot recurse into regular file entries. */
    return false;
  }
  if (FILENAME_IS_CURRPAR(entry->relpath)) {
    /* Don't schedule go to parent entry, (`..`) */
    return false;
  }

  return true;
}

static void filelist_readjob_recursive_dir_add_items(const bool do_lib,
                                                     FileListReadJob *job_params,
                                                     const bool *stop,
                                                     bool *do_update,
                                                     float *progress)
{
  FileList *filelist = job_params->tmp_filelist; /* Use the thread-safe filelist queue. */
  ListBase entries = {nullptr};
  BLI_Stack *todo_dirs;
  TodoDir *td_dir;
  char dir[FILE_MAX_LIBEXTRA];
  char filter_glob[FILE_MAXFILE];
  const char *root = filelist->filelist.root;
  const int max_recursion = filelist->max_recursion;
  int dirs_done_count = 0, dirs_todo_count = 1;

  todo_dirs = BLI_stack_new(sizeof(*td_dir), __func__);
  td_dir = static_cast<TodoDir *>(BLI_stack_push_r(todo_dirs));
  td_dir->level = 1;

  BLI_strncpy(dir, filelist->filelist.root, sizeof(dir));
  BLI_strncpy(filter_glob, filelist->filter_data.filter_glob, sizeof(filter_glob));

  BLI_path_normalize_dir(job_params->main_name, dir, sizeof(dir));
  td_dir->dir = BLI_strdup(dir);

  /* Init the file indexer. */
  FileIndexer indexer_runtime{};
  indexer_runtime.callbacks = filelist->indexer;
  if (indexer_runtime.callbacks->init_user_data) {
    indexer_runtime.user_data = indexer_runtime.callbacks->init_user_data(dir, sizeof(dir));
  }

  while (!BLI_stack_is_empty(todo_dirs) && !(*stop)) {
    int entries_num = 0;

    char *subdir;
    char rel_subdir[FILE_MAX_LIBEXTRA];
    int recursion_level;
    bool skip_currpar;

    td_dir = static_cast<TodoDir *>(BLI_stack_peek(todo_dirs));
    subdir = td_dir->dir;
    recursion_level = td_dir->level;
    skip_currpar = (recursion_level > 1);

    BLI_stack_discard(todo_dirs);

    /* ARRRG! We have to be very careful *not to use* common BLI_path_util helpers over
     * entry->relpath itself (nor any path containing it), since it may actually be a datablock
     * name inside .blend file, which can have slashes and backslashes! See T46827.
     * Note that in the end, this means we 'cache' valid relative subdir once here,
     * this is actually better. */
    BLI_strncpy(rel_subdir, subdir, sizeof(rel_subdir));
    BLI_path_normalize_dir(root, rel_subdir, sizeof(rel_subdir));
    BLI_path_rel(rel_subdir, root);

    bool is_lib = false;
    if (do_lib) {
      ListLibOptions list_lib_options = LIST_LIB_OPTION_NONE;
      if (!skip_currpar) {
        list_lib_options |= LIST_LIB_ADD_PARENT;
      }

      /* Libraries are loaded recursively when max_recursion is set. It doesn't check if there is
       * still a recursion level over. */
      if (max_recursion > 0) {
        list_lib_options |= LIST_LIB_RECURSIVE;
      }
      /* Only load assets when browsing an asset library. For normal file browsing we return all
       * entries. `FLF_ASSETS_ONLY` filter can be enabled/disabled by the user. */
      if (filelist->asset_library_ref) {
        list_lib_options |= LIST_LIB_ASSETS_ONLY;
      }
      entries_num = filelist_readjob_list_lib(
          filelist, subdir, &entries, list_lib_options, &indexer_runtime);
      if (entries_num > 0) {
        is_lib = true;
      }
    }

    if (!is_lib) {
      entries_num = filelist_readjob_list_dir(
          subdir, &entries, filter_glob, do_lib, job_params->main_name, skip_currpar);
    }

    LISTBASE_FOREACH (FileListInternEntry *, entry, &entries) {
      entry->uid = filelist_uid_generate(filelist);

      /* When loading entries recursive, the `rel_path` should be relative from the root dir.
       * we combine the relative path to the `subdir` with the relative path of the entry.
       * Using #BLI_path_join works but isn't needed as `rel_subdir` has a trailing slash. */
      BLI_string_join(dir, sizeof(dir), rel_subdir, entry->relpath);
      MEM_freeN(entry->relpath);
      entry->relpath = BLI_strdup(dir + 2); /* + 2 to remove '//'
                                             * added by BLI_path_rel to rel_subdir. */
      entry->name = fileentry_uiname(root, entry, dir);
      entry->free_name = true;

      if (filelist_readjob_should_recurse_into_entry(
              max_recursion, is_lib, recursion_level, entry)) {
        /* We have a directory we want to list, add it to todo list!
         * Using #BLI_path_join works but isn't needed as `root` has a trailing slash. */
        BLI_string_join(dir, sizeof(dir), root, entry->relpath);
        BLI_path_normalize_dir(job_params->main_name, dir, sizeof(dir));
        td_dir = static_cast<TodoDir *>(BLI_stack_push_r(todo_dirs));
        td_dir->level = recursion_level + 1;
        td_dir->dir = BLI_strdup(dir);
        dirs_todo_count++;
      }
    }

    filelist_readjob_append_entries(job_params, &entries, entries_num, do_update);

    dirs_done_count++;
    *progress = float(dirs_done_count) / float(dirs_todo_count);
    MEM_freeN(subdir);
  }

  /* Finalize and free indexer. */
  if (indexer_runtime.callbacks->filelist_finished && BLI_stack_is_empty(todo_dirs)) {
    indexer_runtime.callbacks->filelist_finished(indexer_runtime.user_data);
  }
  if (indexer_runtime.callbacks->free_user_data && indexer_runtime.user_data) {
    indexer_runtime.callbacks->free_user_data(indexer_runtime.user_data);
    indexer_runtime.user_data = nullptr;
  }

  /* If we were interrupted by stop, stack may not be empty and we need to free
   * pending dir paths. */
  while (!BLI_stack_is_empty(todo_dirs)) {
    td_dir = static_cast<TodoDir *>(BLI_stack_peek(todo_dirs));
    MEM_freeN(td_dir->dir);
    BLI_stack_discard(todo_dirs);
  }
  BLI_stack_free(todo_dirs);
}

static void filelist_readjob_do(const bool do_lib,
                                FileListReadJob *job_params,
                                const bool *stop,
                                bool *do_update,
                                float *progress)
{
  FileList *filelist = job_params->tmp_filelist; /* Use the thread-safe filelist queue. */

  //  BLI_assert(filelist->filtered == nullptr);
  BLI_assert(BLI_listbase_is_empty(&filelist->filelist.entries) &&
             (filelist->filelist.entries_num == FILEDIR_NBR_ENTRIES_UNSET));

  /* A valid, but empty directory from now. */
  filelist->filelist.entries_num = 0;

  filelist_readjob_recursive_dir_add_items(do_lib, job_params, stop, do_update, progress);
}

static void filelist_readjob_dir(FileListReadJob *job_params,
                                 bool *stop,
                                 bool *do_update,
                                 float *progress)
{
  filelist_readjob_do(false, job_params, stop, do_update, progress);
}

static void filelist_readjob_lib(FileListReadJob *job_params,
                                 bool *stop,
                                 bool *do_update,
                                 float *progress)
{
  filelist_readjob_do(true, job_params, stop, do_update, progress);
}

/**
 * Load asset library data, which currently means loading the asset catalogs for the library.
 */
static void filelist_readjob_load_asset_library_data(FileListReadJob *job_params, bool *do_update)
{
  FileList *tmp_filelist = job_params->tmp_filelist; /* Use the thread-safe filelist queue. */

  *do_update = false;

  if (job_params->filelist->asset_library_ref == nullptr) {
    return;
  }
  if (tmp_filelist->asset_library != nullptr) {
    /* Asset library already loaded. */
    return;
  }

  /* Load asset catalogs, into the temp filelist for thread-safety.
   * #filelist_readjob_endjob() will move it into the real filelist. */
  tmp_filelist->asset_library = BKE_asset_library_load(job_params->current_main,
                                                       *job_params->filelist->asset_library_ref);
  *do_update = true;
}

static void filelist_readjob_main_assets_add_items(FileListReadJob *job_params,
                                                   bool * /*stop*/,
                                                   bool *do_update,
                                                   float * /*progress*/)
{
  FileList *filelist = job_params->tmp_filelist; /* Use the thread-safe filelist queue. */

  FileListInternEntry *entry;
  ListBase tmp_entries = {0};
  ID *id_iter;
  int entries_num = 0;

  /* Make sure no IDs are added/removed/reallocated in the main thread while this is running in
   * parallel. */
  BKE_main_lock(job_params->current_main);

  FOREACH_MAIN_ID_BEGIN (job_params->current_main, id_iter) {
    if (!id_iter->asset_data || ID_IS_LINKED(id_iter)) {
      continue;
    }

    const char *id_code_name = BKE_idtype_idcode_to_name(GS(id_iter->name));

    entry = MEM_cnew<FileListInternEntry>(__func__);
    entry->relpath = BLI_strdup(id_code_name);
    entry->name = id_iter->name + 2;
    entry->free_name = false;
    entry->typeflag |= FILE_TYPE_BLENDERLIB | FILE_TYPE_ASSET;
    entry->blentype = GS(id_iter->name);
    entry->uid = filelist_uid_generate(filelist);
    entry->local_data.preview_image = BKE_asset_metadata_preview_get_from_id(id_iter->asset_data,
                                                                             id_iter);
    entry->local_data.id = id_iter;
    if (filelist->asset_library) {
      entry->asset = &filelist->asset_library->add_local_id_asset(*id_iter);
    }
    entries_num++;
    BLI_addtail(&tmp_entries, entry);
  }
  FOREACH_MAIN_ID_END;

  BKE_main_unlock(job_params->current_main);

  if (entries_num) {
    *do_update = true;

    BLI_movelisttolist(&filelist->filelist.entries, &tmp_entries);
    filelist->filelist.entries_num += entries_num;
    filelist->filelist.entries_filtered_num = -1;
  }
}

/**
 * Check if \a bmain is stored within the root path of \a filelist. This means either directly or
 * in some nested directory. In other words, it checks if the \a filelist root path is contained in
 * the path to \a bmain.
 * This is irrespective of the recursion level displayed, it basically assumes unlimited recursion
 * levels.
 */
static bool filelist_contains_main(const FileList *filelist, const Main *bmain)
{
  const char *blendfile_path = BKE_main_blendfile_path(bmain);
  return blendfile_path[0] && BLI_path_contains(filelist->filelist.root, blendfile_path);
}

static void filelist_readjob_asset_library(FileListReadJob *job_params,
                                           bool *stop,
                                           bool *do_update,
                                           float *progress)
{
  FileList *filelist = job_params->tmp_filelist; /* Use the thread-safe filelist queue. */

  BLI_assert(BLI_listbase_is_empty(&filelist->filelist.entries) &&
             (filelist->filelist.entries_num == FILEDIR_NBR_ENTRIES_UNSET));

  /* A valid, but empty file-list from now. */
  filelist->filelist.entries_num = 0;

  /* NOP if already read. */
  filelist_readjob_load_asset_library_data(job_params, do_update);

  if (filelist_contains_main(filelist, job_params->current_main)) {
    filelist_readjob_main_assets_add_items(job_params, stop, do_update, progress);
  }
  if (!job_params->only_main_data) {
    filelist_readjob_recursive_dir_add_items(true, job_params, stop, do_update, progress);
  }
}

static void filelist_readjob_main(FileListReadJob *job_params,
                                  bool *stop,
                                  bool *do_update,
                                  float *progress)
{
  /* TODO! */
  filelist_readjob_dir(job_params, stop, do_update, progress);
}

static void filelist_readjob_main_assets(FileListReadJob *job_params,
                                         bool *stop,
                                         bool *do_update,
                                         float *progress)
{
  FileList *filelist = job_params->tmp_filelist; /* Use the thread-safe filelist queue. */
  BLI_assert(BLI_listbase_is_empty(&filelist->filelist.entries) &&
             (filelist->filelist.entries_num == FILEDIR_NBR_ENTRIES_UNSET));

  filelist_readjob_load_asset_library_data(job_params, do_update);

  /* A valid, but empty file-list from now. */
  filelist->filelist.entries_num = 0;

  filelist_readjob_main_assets_add_items(job_params, stop, do_update, progress);
}

/**
 * Check if the read-job is requesting a partial reread of the file list only.
 */
static bool filelist_readjob_is_partial_read(const FileListReadJob *read_job)
{
  return read_job->only_main_data;
}

/**
 * \note This may trigger partial filelist reading. If the #FL_FORCE_RESET_MAIN_FILES flag is set,
 *       some current entries are kept and we just call the readjob to update the main files (see
 *       #FileListReadJob.only_main_data).
 */
static void filelist_readjob_startjob(void *flrjv, bool *stop, bool *do_update, float *progress)
{
  FileListReadJob *flrj = static_cast<FileListReadJob *>(flrjv);

  //  printf("START filelist reading (%d files, main thread: %d)\n",
  //         flrj->filelist->filelist.entries_num, BLI_thread_is_main());

  BLI_mutex_lock(&flrj->lock);

  BLI_assert((flrj->tmp_filelist == nullptr) && flrj->filelist);

  flrj->tmp_filelist = static_cast<FileList *>(MEM_dupallocN(flrj->filelist));

  BLI_listbase_clear(&flrj->tmp_filelist->filelist.entries);
  flrj->tmp_filelist->filelist.entries_num = FILEDIR_NBR_ENTRIES_UNSET;

  flrj->tmp_filelist->filelist_intern.filtered = nullptr;
  BLI_listbase_clear(&flrj->tmp_filelist->filelist_intern.entries);
  if (filelist_readjob_is_partial_read(flrj)) {
    /* Don't unset the current UID on partial read, would give duplicates otherwise. */
  }
  else {
    filelist_uid_unset(&flrj->tmp_filelist->filelist_intern.curr_uid);
  }

  flrj->tmp_filelist->libfiledata = nullptr;
  memset(&flrj->tmp_filelist->filelist_cache, 0, sizeof(flrj->tmp_filelist->filelist_cache));
  flrj->tmp_filelist->selection_state = nullptr;
  flrj->tmp_filelist->asset_library_ref = nullptr;
  flrj->tmp_filelist->filter_data.asset_catalog_filter = nullptr;

  BLI_mutex_unlock(&flrj->lock);

  flrj->tmp_filelist->read_job_fn(flrj, stop, do_update, progress);
}

/**
 * \note This may update for a partial filelist reading job. If the #FL_FORCE_RESET_MAIN_FILES flag
 *       is set, some current entries are kept and we just call the readjob to update the main
 *       files (see #FileListReadJob.only_main_data).
 */
static void filelist_readjob_update(void *flrjv)
{
  FileListReadJob *flrj = static_cast<FileListReadJob *>(flrjv);
  FileListIntern *fl_intern = &flrj->filelist->filelist_intern;
  ListBase new_entries = {nullptr};
  int entries_num, new_entries_num = 0;

  BLI_movelisttolist(&new_entries, &fl_intern->entries);
  entries_num = flrj->filelist->filelist.entries_num;

  BLI_mutex_lock(&flrj->lock);

  if (flrj->tmp_filelist->filelist.entries_num > 0) {
    /* We just move everything out of 'thread context' into final list. */
    new_entries_num = flrj->tmp_filelist->filelist.entries_num;
    BLI_movelisttolist(&new_entries, &flrj->tmp_filelist->filelist.entries);
    flrj->tmp_filelist->filelist.entries_num = 0;
  }

  if (flrj->tmp_filelist->asset_library) {
    flrj->filelist->asset_library = flrj->tmp_filelist->asset_library;
  }

  /* Important for partial reads: Copy increased UID counter back to the real list. */
  if (flrj->tmp_filelist->filelist_intern.curr_uid > fl_intern->curr_uid) {
    fl_intern->curr_uid = flrj->tmp_filelist->filelist_intern.curr_uid;
  }

  BLI_mutex_unlock(&flrj->lock);

  if (new_entries_num) {
    /* Do not clear selection cache, we can assume already 'selected' UIDs are still valid! Keep
     * the asset library data we just read. */
    filelist_clear_ex(flrj->filelist, false, true, false);

    flrj->filelist->flags |= (FL_NEED_SORTING | FL_NEED_FILTERING);
  }

  /* if no new_entries_num, this is NOP */
  BLI_movelisttolist(&fl_intern->entries, &new_entries);
  flrj->filelist->filelist.entries_num = MAX2(entries_num, 0) + new_entries_num;
}

static void filelist_readjob_endjob(void *flrjv)
{
  FileListReadJob *flrj = static_cast<FileListReadJob *>(flrjv);

  /* In case there would be some dangling update... */
  filelist_readjob_update(flrjv);

  flrj->filelist->flags &= ~FL_IS_PENDING;
  flrj->filelist->flags |= FL_IS_READY;
}

static void filelist_readjob_free(void *flrjv)
{
  FileListReadJob *flrj = static_cast<FileListReadJob *>(flrjv);

  //  printf("END filelist reading (%d files)\n", flrj->filelist->filelist.entries_num);

  if (flrj->tmp_filelist) {
    /* tmp_filelist shall never ever be filtered! */
    BLI_assert(flrj->tmp_filelist->filelist.entries_num == 0);
    BLI_assert(BLI_listbase_is_empty(&flrj->tmp_filelist->filelist.entries));

    filelist_freelib(flrj->tmp_filelist);
    filelist_free(flrj->tmp_filelist);
    MEM_freeN(flrj->tmp_filelist);
  }

  BLI_mutex_end(&flrj->lock);

  MEM_freeN(flrj);
}

void filelist_readjob_start(FileList *filelist, const int space_notifier, const bContext *C)
{
  Main *bmain = CTX_data_main(C);
  wmJob *wm_job;
  FileListReadJob *flrj;

  if (!filelist_is_dir(filelist, filelist->filelist.root)) {
    return;
  }

  /* prepare job data */
  flrj = MEM_cnew<FileListReadJob>(__func__);
  flrj->filelist = filelist;
  flrj->current_main = bmain;
  BLI_strncpy(flrj->main_name, BKE_main_blendfile_path(bmain), sizeof(flrj->main_name));
  if ((filelist->flags & FL_FORCE_RESET_MAIN_FILES) && !(filelist->flags & FL_FORCE_RESET)) {
    flrj->only_main_data = true;
  }

  filelist->flags &= ~(FL_FORCE_RESET | FL_FORCE_RESET_MAIN_FILES | FL_IS_READY);
  filelist->flags |= FL_IS_PENDING;

  /* Init even for single threaded execution. Called functions use it. */
  BLI_mutex_init(&flrj->lock);

  /* The file list type may not support threading so execute immediately. Same when only rereading
   * #Main data (which we do quite often on changes to #Main, since it's the easiest and safest way
   * to ensure the displayed data is up to date), because some operations executing right after
   * main data changed may need access to the ID files (see T93691). */
  const bool no_threads = (filelist->tags & FILELIST_TAGS_NO_THREADS) || flrj->only_main_data;

  if (no_threads) {
    bool dummy_stop = false;
    bool 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, space_notifier | NA_JOB_FINISHED, nullptr);
    return;
  }

  /* setup job */
  wm_job = WM_jobs_get(CTX_wm_manager(C),
                       CTX_wm_window(C),
                       filelist,
                       "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, space_notifier, space_notifier | NA_JOB_FINISHED);
  WM_jobs_callbacks(wm_job,
                    filelist_readjob_startjob,
                    nullptr,
                    filelist_readjob_update,
                    filelist_readjob_endjob);

  /* start the job */
  WM_jobs_start(CTX_wm_manager(C), wm_job);
}

void filelist_readjob_stop(FileList *filelist, wmWindowManager *wm)
{
  WM_jobs_kill_type(wm, filelist, WM_JOB_TYPE_FILESEL_READDIR);
}

int filelist_readjob_running(FileList *filelist, wmWindowManager *wm)
{
  return WM_jobs_test(wm, filelist, WM_JOB_TYPE_FILESEL_READDIR);
}