anchor.diff:      } catch (e, st) {
         _log.severe(e, st);
         for (FileSystemEntity fse in filesWritten) {
  -        if(fse==null)
  -          continue;
  +        if (fse == null) continue;
   
           try {
             final bool exists = await fse.exists();
  
positive.code:     _log.fine("File hash: ${item.id}");
  
      _log.fine("Checking if item already exists");
      if(await itemDataSource.existsById(item.id))
        throw new DuplicateItemException("Item ${item.id} already imported");
  
      final List<FileSystemEntity> filesWritten = <FileSystemEntity>[];
  
negative.code:         originalImage = decodeImage(item.fileData);
          _log.fine("image decoded");
        }
        if (mime == MimeTypes.jpeg || mime == MimeTypes.tiff) {
          try {
            _log.fine("Reading exif data");
            final Map<String, IfdTag> data =
                await readExifFromFile(new File(originalFile));
            for (String key in data.keys) {
              item.metadata[key] = data[key].toString();
            }
            _log.fine("Done reading exif data", item.metadata);
          } catch (e, st) {
            _log.warning("Error while fetching exif data", e, st);
            item.errors.add("Error while fetching exif data: ${e.toString()}");
          }
        }
      } else if (MimeTypes.videoTypes.contains(mime) || mime == MimeTypes.swf) {
        try {
          _log.fine("Is video mime type");
          item.video = true;
          originalImage = decodePng(await generateFfmpegThumbnail(originalFile));
          await getFfprobeData(item, originalFile);
        } catch (e, st) {
          if (mime == MimeTypes.swf) {
            _log.warning("Error while genereting thumbnail of swf", e, st);
            item.errors
                .add("Error while genereting thumbnail of swf: ${e.toString()}");
          } else {
            rethrow;
          }
  