service: add a diff() operation on writers

This diffs the given changeset with the uncommited changes in the
writer.  The result is effectively the changeset that would have to be
applied to the writer to cause it to be equal to the passed-in
changeset.

2 files changed, 9 insertions, 0 deletions

diff --git a/service/dconf-writer.c b/service/dconf-writer.c
index 6df600a..a907b55 100644
--- a/service/dconf-writer.c
+++ b/service/dconf-writer.c
@@ -359,6 +359,13 @@ dconf_writer_set_basepath (DConfWriter *writer,
   writer->priv->native = FALSE;
 }
 
+DConfChangeset *
+dconf_writer_diff (DConfWriter    *writer,
+                   DConfChangeset *changeset)
+{
+  return dconf_changeset_diff (writer->priv->uncommited_values, changeset);
+}
+
 const gchar *
 dconf_writer_get_name (DConfWriter *writer)
 {
diff --git a/service/dconf-writer.h b/service/dconf-writer.h
index 4892197..5e8e0a1 100644
--- a/service/dconf-writer.h
+++ b/service/dconf-writer.h
@@ -74,6 +74,8 @@ GType                   dconf_shm_writer_get_type                       (void);
 
 void                    dconf_writer_set_basepath                       (DConfWriter *writer,
                                                                          const gchar *name);
+DConfChangeset *        dconf_writer_diff                               (DConfWriter *writer,
+                                                                         DConfChangeset *changeset);
 
 void                    dconf_writer_list                               (GType        type,
                                                                          GHashTable  *set);