Allow viewing/selecting files in archive formats while downloading

[werrel3]

When downloading a torrent that contains a single huge file in an archive format eg zip, rar, iso, it would be useful to be able to see the list of files inside the archive and be able to select/deselect individual files for download while the torrent is downloading. This could also indicate if the archive is password protected.

Obviously Transmission would need to download the pieces containing the archive index first. Perhaps some sort of plugin mechanism could be used to allow support for different archive formats.

There is also the issue of how to store the archive with missing files. Depending on how the archive format it may be possible to just leave the non downloaded pieces as all zeroes (or holes on filesystems that support it) and let the unarchive application report some files as not extractable due to checksum errors.

If selecting individual files for download in an archive is not feasible it would still be useful to be able to list the contents of archives while downloading as some torrents are posted in an archive format with little or no description of their contents.

[mike.dld]

This sounds too advanced to me, and out of scope of this project.