text: /*
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version 2
   * of the License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
   */
  
  /** \file
   * \ingroup imbuf
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "BLI_linklist.h"
  #include "BLI_listbase.h" /* Needed due to import of BLO_readfile.h */
  #include "BLI_utildefines.h"
  
  #include "BLO_blend_defs.h"
  #include "BLO_readfile.h"
  
  #include "BKE_icons.h"
  #include "BKE_idtype.h"
  #include "BKE_main.h"
  
  #include "DNA_ID.h" /* For preview images... */
  
  #include "IMB_imbuf.h"
  #include "IMB_imbuf_types.h"
  #include "IMB_thumbs.h"
  
  #include "MEM_guardedalloc.h"
  
  ImBuf *IMB_thumb_load_blend(const char *blen_path, const char *blen_group, const char *blen_id)
  {
    ImBuf *ima = NULL;
  
    if (blen_group && blen_id) {
      LinkNode *ln, *names, *lp, *previews = NULL;
      struct BlendHandle *libfiledata = BLO_blendhandle_from_file(blen_path, NULL);
      int idcode = BKE_idtype_idcode_from_name(blen_group);
      int i, nprevs, nnames;
  
      if (libfiledata == NULL) {
        return ima;
      }
  
      /* Note: we should handle all previews for a same group at once, would avoid reopening
       * `.blend` file for each and every ID. However, this adds some complexity,
       * so keep it for later. */
      names = BLO_blendhandle_get_datablock_names(libfiledata, idcode, false, &nnames);
      previews = BLO_blendhandle_get_previews(libfiledata, idcode, &nprevs);
  
      BLO_blendhandle_close(libfiledata);
  
      if (!previews || (nnames != nprevs)) {
        if (previews != 0) {
          /* No previews at all is not a bug! */
          printf("%s: error, found %d items, %d previews\n", __func__, nnames, nprevs);
        }
        BLI_linklist_free(previews, BKE_previewimg_freefunc);
        BLI_linklist_freeN(names);
        return ima;
      }
  
      for (i = 0, ln = names, lp = previews; i < nnames; i++, ln = ln->next, lp = lp->next) {
        const char *blockname = ln->link;
        PreviewImage *img = lp->link;
  
        if (STREQ(blockname, blen_id)) {
          if (img) {
            ima = BKE_previewimg_to_imbuf(img, ICON_SIZE_PREVIEW);
          }
          break;
        }
      }
  
      BLI_linklist_free(previews, BKE_previewimg_freefunc);
      BLI_linklist_freeN(names);
    }
    else {
      BlendThumbnail *data;
  
      data = BLO_thumbnail_from_file(blen_path);
      ima = BKE_main_thumbnail_to_imbuf(NULL, data);
  
      if (data) {
        MEM_freeN(data);
      }
    }
  
    return ima;
  }
  