Transparent archive handling

Ways to do it:
 1) Patch GVFS to make it use our backend and make Marlin use it for archives, write a custom GtkFileChooser backend (limited to Marlin and GTK)
 2) Make on-demand FUSE folders for archives and hide the archive files with gobohide

The best backend possible is File Roller turned into a library.

I don't think this is a good idea. There should be a clear separation between when something is packed or not. If you want instant access to archives, they should extract on open instead of opening the archive manager. The best solution is not typically the more complex one -- DanRabbit

DanRabbit: what if I have a tiny SSD and want my files to be stored compressed? Many programs like GIMP don't compress their XCF files but handle .XCF.GZ and .XCF.BZ2 like they're not compressed. Does that mean that to modify the compressed file I'll have to extract it, modify it, delete the old archive and pack the new file? That's WAY too much effort.
In case we use a content library instead of the filesystem structure we can utilize a compressed filesystem like fusecompress, but AFAIK we're not even close to that yet. ~shnatsel

File-roller depends on Nautilis in latest version, so we have to patch it or find an alternative. ~shnatsel

FYI: I registered a similar blueprint a while back, and elaborated on the way marlin should/could handle archives containing either single or multiple files (https://blueprints.launchpad.net/marlin/+spec/archive-manager-integration). The long and the short of it; I concluded that the end-user shouldn't 'see' a distinction between compressed archives and folders/files. The exception being for advanced archiving management such as tweaking archive parameters and/or parity files, where a stand alone archive manager (e.g. file-roller) is best practice IMO. ~anubeon

Marking as superseded since there is a Marlin blueprint and that's where the work should be done if it's ever approved --DanRabbit

What about "open file" dialog? --shnatsel