settings: make NMSettingsPlugin a regular GObject instance and not an interface

NMSettingsPlugin was a glib interface, not a regular GObject
instance. Accordingly, settings plugins would implement this interface
instead of subclassing a parent type.

Refactor the code, and make NMSettingsPlugin a GObject type. Plugins
are now required to subclass this type.

Glib interfaces are more cumbersome than helpful. At least, unless
there is a good reason for using them.

Our settings plugins are all internal API and are entirely under
our control. It also means, this change is fine, as there are no
implementations outside of this source tree.

Using interfaces do would allow more flexibility in implementing the
settings plugin.
For example, the plugin would be able to derive from any other GObject
type, like NMKimchiRefrigerator. But why would we even? Let's not add monster
classes that implement house appliances beside NMSettingsPluginInterface.
The settings plugin should have one purpose only: being a settings plugin.
Hence, requiring it to subclass NMSettingsPlugin is more than resonable. We
don't need interfaces for this.

Now that NMSettingsPlugin is a regular object instance, it may also have
state, and potentially could provide common functionality for the plugin
implementation -- if that turns out to be useful. Arguably, an interface can
have state too, for example by attaching the state somewhere else (like
NMConnection does). But let's just say no.

On a minor note, this also avoids some tiny overhead that comes with
glib interfaces.

1 files changed, 113 insertions, 70 deletions

diff --git a/src/settings/nm-settings-plugin.c b/src/settings/nm-settings-plugin.c
index 212311387b..e7275631dc 100644
--- a/src/settings/nm-settings-plugin.c
+++ b/src/settings/nm-settings-plugin.c
@@ -15,117 +15,94 @@
  * with this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  *
- * Copyright (C) 2007 - 2011 Red Hat, Inc.
+ * Copyright (C) 2007 - 2018 Red Hat, Inc.
  * Copyright (C) 2008 Novell, Inc.
  */
 
 #include "nm-default.h"
 
 #include "nm-settings-plugin.h"
+
 #include "nm-settings-connection.h"
 
-G_DEFINE_INTERFACE (NMSettingsPlugin, nm_settings_plugin, G_TYPE_OBJECT)
+/*****************************************************************************/
 
-static void
-nm_settings_plugin_default_init (NMSettingsPluginInterface *g_iface)
-{
-	GType iface_type = G_TYPE_FROM_INTERFACE (g_iface);
-	static gboolean initialized = FALSE;
-
-	if (initialized)
-		return;
-
-	/* Signals */
-	g_signal_new (NM_SETTINGS_PLUGIN_CONNECTION_ADDED,
-	              iface_type,
-	              G_SIGNAL_RUN_FIRST,
-	              G_STRUCT_OFFSET (NMSettingsPluginInterface, connection_added),
-	              NULL, NULL,
-	              g_cclosure_marshal_VOID__OBJECT,
-	              G_TYPE_NONE, 1,
-	              NM_TYPE_SETTINGS_CONNECTION);
-
-	g_signal_new (NM_SETTINGS_PLUGIN_UNMANAGED_SPECS_CHANGED,
-	              iface_type,
-	              G_SIGNAL_RUN_FIRST,
-	              G_STRUCT_OFFSET (NMSettingsPluginInterface, unmanaged_specs_changed),
-	              NULL, NULL,
-	              g_cclosure_marshal_VOID__VOID,
-	              G_TYPE_NONE, 0);
-
-	g_signal_new (NM_SETTINGS_PLUGIN_UNRECOGNIZED_SPECS_CHANGED,
-	              iface_type,
-	              G_SIGNAL_RUN_FIRST,
-	              G_STRUCT_OFFSET (NMSettingsPluginInterface, unrecognized_specs_changed),
-	              NULL, NULL,
-	              g_cclosure_marshal_VOID__VOID,
-	              G_TYPE_NONE, 0);
-
-	initialized = TRUE;
-}
+enum {
+	CONNECTION_ADDED,
+	UNMANAGED_SPECS_CHANGED,
+	UNRECOGNIZED_SPECS_CHANGED,
+
+	LAST_SIGNAL
+};
+
+static guint signals[LAST_SIGNAL] = { 0 };
+
+G_DEFINE_TYPE (NMSettingsPlugin, nm_settings_plugin, G_TYPE_OBJECT)
+
+/*****************************************************************************/
 
 void
-nm_settings_plugin_initialize (NMSettingsPlugin *config)
+nm_settings_plugin_initialize (NMSettingsPlugin *self)
 {
-	g_return_if_fail (config != NULL);
+	g_return_if_fail (NM_IS_SETTINGS_PLUGIN (self));
 
-	if (NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->initialize)
-		NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->initialize (config);
+	if (NM_SETTINGS_PLUGIN_GET_CLASS (self)->initialize)
+		NM_SETTINGS_PLUGIN_GET_CLASS (self)->initialize (self);
 }
 
 GSList *
-nm_settings_plugin_get_connections (NMSettingsPlugin *config)
+nm_settings_plugin_get_connections (NMSettingsPlugin *self)
 {
-	g_return_val_if_fail (config != NULL, NULL);
+	g_return_val_if_fail (NM_IS_SETTINGS_PLUGIN (self), NULL);
 
-	if (NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->get_connections)
-		return NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->get_connections (config);
+	if (NM_SETTINGS_PLUGIN_GET_CLASS (self)->get_connections)
+		return NM_SETTINGS_PLUGIN_GET_CLASS (self)->get_connections (self);
 	return NULL;
 }
 
 gboolean
-nm_settings_plugin_load_connection (NMSettingsPlugin *config,
+nm_settings_plugin_load_connection (NMSettingsPlugin *self,
                                     const char *filename)
 {
-	g_return_val_if_fail (config != NULL, FALSE);
+	g_return_val_if_fail (NM_IS_SETTINGS_PLUGIN (self), FALSE);
 
-	if (NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->load_connection)
-		return NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->load_connection (config, filename);
+	if (NM_SETTINGS_PLUGIN_GET_CLASS (self)->load_connection)
+		return NM_SETTINGS_PLUGIN_GET_CLASS (self)->load_connection (self, filename);
 	return FALSE;
 }
 
 void
-nm_settings_plugin_reload_connections (NMSettingsPlugin *config)
+nm_settings_plugin_reload_connections (NMSettingsPlugin *self)
 {
-	g_return_if_fail (config != NULL);
+	g_return_if_fail (NM_IS_SETTINGS_PLUGIN (self));
 
-	if (NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->reload_connections)
-		NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->reload_connections (config);
+	if (NM_SETTINGS_PLUGIN_GET_CLASS (self)->reload_connections)
+		NM_SETTINGS_PLUGIN_GET_CLASS (self)->reload_connections (self);
 }
 
 GSList *
-nm_settings_plugin_get_unmanaged_specs (NMSettingsPlugin *config)
+nm_settings_plugin_get_unmanaged_specs (NMSettingsPlugin *self)
 {
-	g_return_val_if_fail (config != NULL, NULL);
+	g_return_val_if_fail (NM_IS_SETTINGS_PLUGIN (self), NULL);
 
-	if (NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->get_unmanaged_specs)
-		return NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->get_unmanaged_specs (config);
+	if (NM_SETTINGS_PLUGIN_GET_CLASS (self)->get_unmanaged_specs)
+		return NM_SETTINGS_PLUGIN_GET_CLASS (self)->get_unmanaged_specs (self);
 	return NULL;
 }
 
 GSList *
-nm_settings_plugin_get_unrecognized_specs (NMSettingsPlugin *config)
+nm_settings_plugin_get_unrecognized_specs (NMSettingsPlugin *self)
 {
-	g_return_val_if_fail (config != NULL, NULL);
+	g_return_val_if_fail (NM_IS_SETTINGS_PLUGIN (self), NULL);
 
-	if (NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->get_unrecognized_specs)
-		return NM_SETTINGS_PLUGIN_GET_INTERFACE (config)->get_unrecognized_specs (config);
+	if (NM_SETTINGS_PLUGIN_GET_CLASS (self)->get_unrecognized_specs)
+		return NM_SETTINGS_PLUGIN_GET_CLASS (self)->get_unrecognized_specs (self);
 	return NULL;
 }
 
 /**
  * nm_settings_plugin_add_connection:
- * @config: the #NMSettingsPlugin
+ * @self: the #NMSettingsPlugin
  * @connection: the source connection to create a plugin-specific
  * #NMSettingsConnection from
  * @save_to_disk: %TRUE to save the connection to disk immediately, %FALSE to
@@ -140,22 +117,88 @@ nm_settings_plugin_get_unrecognized_specs (NMSettingsPlugin *config)
  * Returns: the new #NMSettingsConnection or %NULL
  */
 NMSettingsConnection *
-nm_settings_plugin_add_connection (NMSettingsPlugin *config,
+nm_settings_plugin_add_connection (NMSettingsPlugin *self,
                                    NMConnection *connection,
                                    gboolean save_to_disk,
                                    GError **error)
 {
-	NMSettingsPluginInterface *config_interface;
+	NMSettingsPluginClass *klass;
 
-	g_return_val_if_fail (config != NULL, NULL);
+	g_return_val_if_fail (NM_IS_SETTINGS_PLUGIN (self), NULL);
 	g_return_val_if_fail (NM_IS_CONNECTION (connection), NULL);
 
-	config_interface = NM_SETTINGS_PLUGIN_GET_INTERFACE (config);
-	if (!config_interface->add_connection) {
+	klass = NM_SETTINGS_PLUGIN_GET_CLASS (self);
+	if (!klass->add_connection) {
 		g_set_error_literal (error, NM_SETTINGS_ERROR, NM_SETTINGS_ERROR_NOT_SUPPORTED,
 		                     "Plugin does not support adding connections");
 		return NULL;
 	}
 
-	return config_interface->add_connection (config, connection, save_to_disk, error);
+	return klass->add_connection (self, connection, save_to_disk, error);
+}
+
+/*****************************************************************************/
+
+void
+_nm_settings_plugin_emit_signal_connection_added (NMSettingsPlugin *self,
+                                                  NMSettingsConnection *sett_conn)
+{
+	nm_assert (NM_IS_SETTINGS_PLUGIN (self));
+	nm_assert (NM_IS_SETTINGS_CONNECTION (sett_conn));
+
+	g_signal_emit (self, signals[CONNECTION_ADDED], 0, sett_conn);
+}
+
+void
+_nm_settings_plugin_emit_signal_unmanaged_specs_changed (NMSettingsPlugin *self)
+{
+	nm_assert (NM_IS_SETTINGS_PLUGIN (self));
+
+	g_signal_emit (self, signals[UNMANAGED_SPECS_CHANGED], 0);
+}
+
+void
+_nm_settings_plugin_emit_signal_unrecognized_specs_changed (NMSettingsPlugin *self)
+{
+	nm_assert (NM_IS_SETTINGS_PLUGIN (self));
+
+	g_signal_emit (self, signals[UNRECOGNIZED_SPECS_CHANGED], 0);
+}
+
+/*****************************************************************************/
+
+static void
+nm_settings_plugin_init (NMSettingsPlugin *self)
+{
+}
+
+static void
+nm_settings_plugin_class_init (NMSettingsPluginClass *klass)
+{
+	GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+	signals[CONNECTION_ADDED] =
+	    g_signal_new (NM_SETTINGS_PLUGIN_CONNECTION_ADDED,
+	                  G_OBJECT_CLASS_TYPE (object_class),
+	                  G_SIGNAL_RUN_FIRST,
+	                  0, NULL, NULL,
+	                  g_cclosure_marshal_VOID__OBJECT,
+	                  G_TYPE_NONE, 1,
+	                  NM_TYPE_SETTINGS_CONNECTION);
+
+	signals[UNMANAGED_SPECS_CHANGED] =
+	    g_signal_new (NM_SETTINGS_PLUGIN_UNMANAGED_SPECS_CHANGED,
+	                  G_OBJECT_CLASS_TYPE (object_class),
+	                  G_SIGNAL_RUN_FIRST,
+	                  0, NULL, NULL,
+	                  g_cclosure_marshal_VOID__VOID,
+	                  G_TYPE_NONE, 0);
+
+	signals[UNRECOGNIZED_SPECS_CHANGED] =
+	    g_signal_new (NM_SETTINGS_PLUGIN_UNRECOGNIZED_SPECS_CHANGED,
+	                  G_OBJECT_CLASS_TYPE (object_class),
+	                  G_SIGNAL_RUN_FIRST,
+	                  0, NULL, NULL,
+	                  g_cclosure_marshal_VOID__VOID,
+	                  G_TYPE_NONE, 0);
 }