You can gtk_file_chooser_set_filter().  Just create a GtkFileFilter, and add a custom filtering callback with gtk_file_filter_add_custom().

Doesn't seem to filter directories. Maybe due to:
  model->filter_folders = FALSE;

?

Hmmm.  There's an internal gtk_file_system_model_set_filter_folders(), and it's just used from GtkFileChooserEntry.

GtkFileChooserDefault could very well use that function.  Can you test how it feels when turned on?  (Do you only need SELECT_FOLDER mode, or do you need to select files as well?)

I *vaguely* remember something about having trouble with filtering folders, but don't have any bugs in mind right now.

Created attachment 218258 [details] [review]
Filter directories when in direction selection mode

This patch seems to work. One issue is that I think for directories it may be better to disable selection (make insensitive) rather than simply hide them. It was a little disconcerting to not see the directories at all.

Perhaps we can add a flag that allows changing the behavior of the filter from hide to disable?

We could have a little gtk_file_filter_set_style (filter, enum { HIDE, DISABLE } ) API, but then we could run into inconsistencies with how apps set that.  This single use case (the "disable the source files/dirs") would be perfect for this, though.

... Alternatively, we could make it so that filtered folders *are* shown, just desensitized.  GtkFileSystemModel does the filtering.  node_should_be_visible() has a big fat "if (is_folder) return TRUE;", which gets passed to node_set_visible() from various places.  Maybe node_should_be_visible() should return a yes/no/disabled enum.

Take your pick; in either case the file system model would need some massaging :)

Created attachment 218436 [details] [review]
Desensitize filtered folders when in folder selection mode

Another thing I noticed is that it would be nice to disallow selecting the current directory (parent of the folders selected to move/copy) but still make the current directory sensitive so you can navigate through it. But we wouldn't want to allow navigating into the folders set to be moved. Not sure how to do that.

I'll be looking at your patch today; thanks!

I've just pushed a filechooser-filtered-folders branch with your patch and some minor changes.

One thing that bothers me is that:

1. node_should_be_filtered_out() calls gtk_file_filter_filter() and negates the result.

2. file_system_model_set() takes *that* and negates the result again.

... even though I put in a commit to s/filtered/filtered_out to make it clear what the result means.

Maybe we should keep "filtered" mean "passed the filter" as usual, and avoid flipping booleans all over the place.  Or we can s/filtered_out/filtered_in and remove the negations.  What do you thinK?

Please make that final change and feel free to merge the branch into master.  Don't forget to add the bug number to the message of the merge commit.  Thanks!

(In reply to comment #9)
> Another thing I noticed is that it would be nice to disallow selecting the
> current directory (parent of the folders selected to move/copy) but still make
> the current directory sensitive so you can navigate through it. But we wouldn't
> want to allow navigating into the folders set to be moved. Not sure how to do
> that.

If you try to move/copy to $cwd/original_name, I'd just make that idempotent and not do anything at all ("the files are where you wanted them to end up").  The folders set to be moved/copied will be insensitive anyway.

See bug #689451 for a bug exposed by this change.

AFAICT this is already merged into master, so I'll close this bug.  The one mentioned in comment #12 is still valid.