changing the "sort" order of "--get-all-files"

I would like to create a patch which would reverse the sort order of "--get-all-files" (with --skip existing). In the case of my Sony RX100M3, the files are organized by date and are sorted from oldest to newest. I would prefer newest files to be pulled down first. The speed of PTPIP on this camera is pretty bad taking several seconds for each directory listing. 

I found the functions in libgphoto2 which are responsible for listing the directories, but am struggling to trace the execution of gphoto CLI with "--get-all-files" to the sequence of "list all folders" (and skip if present). I believe it is similar to the "-l" call which starts with listing of the root and recursively lists all folders.

Any pointers on following the code from execution to downloading for a call with `--get-all-files`?

Aside, an option to stop syncing when we run in to a "date folder" where everything is "skipped" would be handy.

Another aside, the camera communication stability isn't great and often locks up before it even has a chance to list the 100 directories.

Thanks,
Adam