Enhancement: Hide the files that aren't to be downloaded about rtorrent

[rakshasa]

It is a planned feature, yet not going to be done anytime soon.

[pyroscope]

An implementation of this that would add a transparent mapping of "info.files.path" entries to filesystem paths that should be actually used would not add much of an additional implementation burden (instead of say adding a "." in front of deselected files, just do a map lookup instead). This would open the possibility to reroute a torrent's content paths in addition to its root path (which is already possible).

Say, "f.path.target[.set]", storing the map in the session dir under a new key "file_targets". To ease implementation, the setter would error out if the file was already created and the item is not in stopped state; if stopped, it would mark all affected chunks as unseen, so whatever outside party changes a mapping after initial creation must trigger a rehash afterwards.

That could be slighty enhanced to NOT do that if both paths reside in the same filesystem and the target doesn't exist yet (just rename() then). All active mmap()s should survive this, since they're bound to the handle and thus the inode, which doesn't change.