Add sort criterion by reversed extension segments

The basenames of files are split by dots and then starting from the end
each segment is compared to find a sort order. Example:

    bar.tar.bz2
    foo.tar.bz2
    a.bar.gz
    x.tar.gz
    z.tar.gz
    test.tex

A heuristic determines what extension segments are part of the
extension. There is probably no perfect solution but there are much
less false positives. As a result the sorting is more intuitive and the
displayed column in the list view is better readable and displays
extensions more accurately.

In addition a bug related to the default sort criteria in the
preferences has been fixed.

1 files changed, 7 insertions, 0 deletions

diff --git a/libcaja-private/caja-column-utilities.c b/libcaja-private/caja-column-utilities.c
index f63a2034..57dae7f5 100644
--- a/libcaja-private/caja-column-utilities.c
+++ b/libcaja-private/caja-column-utilities.c
@@ -139,6 +139,13 @@ get_builtin_columns (void)
                                            "description", _("The location of the file."),
                                            NULL));
 
+    columns = g_list_append (columns,
+                             g_object_new (CAJA_TYPE_COLUMN,
+                                           "name", "extension",
+                                           "attribute", "extension",
+                                           "label", _("Extension"),
+                                           "description", _("The extension of the file."),
+                                           NULL));
     return columns;
 }