settings: add nm_settings_plugin_cmp_by_priority() function

Initially I thought I would use this somewhere else. Didn't do so far,
but this seems a useful function to have on its own because also
NMSettings is concerned about the relative priority of plugins.

3 files changed, 35 insertions, 22 deletions

diff --git a/src/settings/nm-settings-plugin.c b/src/settings/nm-settings-plugin.c
index 8ae1e6528a..09010931e4 100644
--- a/src/settings/nm-settings-plugin.c
+++ b/src/settings/nm-settings-plugin.c
@@ -42,6 +42,32 @@ G_DEFINE_TYPE (NMSettingsPlugin, nm_settings_plugin, G_TYPE_OBJECT)
 
 /*****************************************************************************/
 
+int
+nm_settings_plugin_cmp_by_priority (const NMSettingsPlugin *a,
+                                    const NMSettingsPlugin *b,
+                                    const GSList *plugin_list)
+{
+	nm_assert (NM_IS_SETTINGS_PLUGIN (a));
+	nm_assert (NM_IS_SETTINGS_PLUGIN (b));
+
+	if (a != b) {
+		int idx_a = g_slist_index ((GSList *) plugin_list, a);
+		int idx_b = g_slist_index ((GSList *) plugin_list, b);
+
+		/* the plugins must be found in the list. */
+		nm_assert (idx_a >= 0);
+		nm_assert (idx_b >= 0);
+
+		/* plugins that appear first in @plugin_list have higher priority.
+		 * That means: smaller index -> higher priority. Reverse sort. */
+		NM_CMP_DIRECT (idx_b, idx_a);
+	}
+
+	return 0;
+}
+
+/*****************************************************************************/
+
 GSList *
 nm_settings_plugin_get_unmanaged_specs (NMSettingsPlugin *self)
 {
diff --git a/src/settings/nm-settings-plugin.h b/src/settings/nm-settings-plugin.h
index 188614bed7..4df3472e76 100644
--- a/src/settings/nm-settings-plugin.h
+++ b/src/settings/nm-settings-plugin.h
@@ -196,6 +196,12 @@ void _nm_settings_plugin_emit_signal_unrecognized_specs_changed (NMSettingsPlugi
 
 /*****************************************************************************/
 
+int nm_settings_plugin_cmp_by_priority (const NMSettingsPlugin *a,
+                                        const NMSettingsPlugin *b,
+                                        const GSList *plugin_list);
+
+/*****************************************************************************/
+
 /* forward declare this function from NMSettings. It's used by the ifcfg-rh plugin,
  * but that shouldn't include all "nm-settings.h" header. */
 NMSettings *nm_settings_get (void);
diff --git a/src/settings/nm-settings-storage.c b/src/settings/nm-settings-storage.c
index c5942c6e02..935b5b48a7 100644
--- a/src/settings/nm-settings-storage.c
+++ b/src/settings/nm-settings-storage.c
@@ -34,8 +34,6 @@ nm_settings_storage_cmp (NMSettingsStorage *a,
                          const GSList *plugin_list)
 {
 	NMSettingsStorageClass *klass;
-	NMSettingsPlugin *plugin_a;
-	NMSettingsPlugin *plugin_b;
 
 	/* Sort by priority.
 	 *
@@ -51,28 +49,11 @@ nm_settings_storage_cmp (NMSettingsStorage *a,
 	NM_CMP_DIRECT (nm_settings_storage_is_keyfile_run (a),
 	               nm_settings_storage_is_keyfile_run (b));
 
-	plugin_a = nm_settings_storage_get_plugin (a);
-	plugin_b = nm_settings_storage_get_plugin (b);
-
-	if (plugin_a != plugin_b) {
-		int idx_a = g_slist_index ((GSList *) plugin_list, plugin_a);
-		int idx_b = g_slist_index ((GSList *) plugin_list, plugin_b);
-
-		/* the plugins must be found in the list. */
-		nm_assert (idx_a >= 0);
-		nm_assert (idx_b >= 0);
-		nm_assert (idx_a != idx_b);
-
-		/* plugins that appear first in @plugin_list have higher priority.
-		 * That means: smaller index -> higher priority. Reverse sort. */
-		NM_CMP_DIRECT (idx_b, idx_a);
-
-		/* undecided. We really don't expect unknown plugins here. */
-		return 0;
-	}
+	NM_CMP_RETURN (nm_settings_plugin_cmp_by_priority (nm_settings_storage_get_plugin (a),
+	                                                   nm_settings_storage_get_plugin (b),
+	                                                   plugin_list));
 
 	klass = NM_SETTINGS_STORAGE_GET_CLASS (a);
-
 	if (klass != NM_SETTINGS_STORAGE_GET_CLASS (b)) {
 		/* one plugin must return storages of the same type. Otherwise, it's
 		 * unclear how cmp_fcn() should compare them. */