dbus: add events to the dbus connection

Add events to the dbus connection and notify about destroy and
disconnect.

spa/include/spa/support/dbus.h

@@ -42,8 +42,23 @@ enum spa_dbus_type {
 	SPA_DBUS_TYPE_STARTER	/**< The bus that started us, if any */
 };
 
+#define SPA_DBUS_CONNECTION_EVENT_DESTROY	0
+#define SPA_DBUS_CONNECTION_EVENT_DISCONNECTED	1
+#define SPA_DBUS_CONNECTION_EVENT_NUM		2
+
+struct spa_dbus_connection_events {
+#define SPA_VERSION_DBUS_CONNECTION_EVENTS	0
+        uint32_t version;
+
+	/* a connection is destroyed */
+	void (*destroy) (void *data);
+
+	/* a connection disconnected */
+	void (*disconnected) (void *data);
+};
+
 struct spa_dbus_connection {
-#define SPA_VERSION_DBUS_CONNECTION	0
+#define SPA_VERSION_DBUS_CONNECTION	1
         uint32_t version;
 	/**
 	 * Get the DBusConnection from a wrapper
@@ -58,10 +73,35 @@ struct spa_dbus_connection {
 	 * \param conn the wrapper to destroy
 	 */
 	void (*destroy) (struct spa_dbus_connection *conn);
+
+	/**
+	 * Add a listener for events
+	 *
+	 * Since version 1
+	 */
+	void (*add_listener) (struct spa_dbus_connection *conn,
+			struct spa_hook *listener,
+			const struct spa_dbus_connection_events *events,
+			void *data);
 };
 
-#define spa_dbus_connection_get(c)	(c)->get((c))
+#define spa_dbus_connection_call(c,method,vers,...)			\
-#define spa_dbus_connection_destroy(c)	(c)->destroy((c))
+({									\
+	if (SPA_LIKELY(SPA_CALLBACK_CHECK(c,method,vers)))		\
+		c->method((c), ## __VA_ARGS__);				\
+})
+
+#define spa_dbus_connection_call_vp(c,method,vers,...)			\
+({									\
+	void *_res = NULL;						\
+	if (SPA_LIKELY(SPA_CALLBACK_CHECK(c,method,vers)))		\
+		_res = c->method((c), ## __VA_ARGS__);			\
+	_res;								\
+})
+
+#define spa_dbus_connection_get(c)		spa_dbus_connection_call_vp(c,get,0)
+#define spa_dbus_connection_destroy(c)		spa_dbus_connection_call(c,destroy,0)
+#define spa_dbus_connection_add_listener(c,...)	spa_dbus_connection_call(c,add_listener,1,__VA_ARGS__)
 
 struct spa_dbus_methods {
 #define SPA_VERSION_DBUS_METHODS	0

spa/plugins/support/dbus.c

@@ -57,6 +57,10 @@ struct source_data {
 	struct connection *conn;
 };
 
+#define connection_emit(c,m,v,...) spa_hook_list_call(&c->listener_list, struct spa_dbus_connection_events, m, v, ##__VA_ARGS__)
+#define connection_emit_destroy(c)	connection_emit(c, destroy, 0)
+#define connection_emit_disconnected(c)	connection_emit(c, disconnected, 0)
+
 struct connection {
 	struct spa_list link;
 
@@ -65,6 +69,8 @@ struct connection {
 	DBusConnection *conn;
 	struct spa_source *dispatch_event;
 	struct spa_list source_list;
+
+	struct spa_hook_list listener_list;
 };
 
 static void source_data_free(void *data)
@@ -279,7 +285,8 @@ static DBusHandlerResult filter_message (DBusConnection *connection,
 	struct impl *impl = this->impl;
 
 	if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
-		spa_log_warn(impl->log, "dbus connection %p disconnected", this);
+		spa_log_debug(impl->log, "dbus connection %p disconnected", this);
+		connection_emit_disconnected(this);
 	}
 	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 }
@@ -308,6 +315,8 @@ static void connection_free(struct connection *conn)
 
 	spa_loop_utils_destroy_source(impl->utils, conn->dispatch_event);
 
+	spa_hook_list_clean(&conn->listener_list);
+
 	free(conn);
 }
 
@@ -317,14 +326,27 @@ impl_connection_destroy(struct spa_dbus_connection *conn)
 	struct connection *this = SPA_CONTAINER_OF(conn, struct connection, this);
 	struct impl *impl = this->impl;
 
+	connection_emit_destroy(this);
+
 	spa_log_debug(impl->log, "destroy conn %p", this);
 	connection_free(this);
 }
 
+static void
+impl_connection_add_listener(struct spa_dbus_connection *conn,
+			struct spa_hook *listener,
+			const struct spa_dbus_connection_events *events,
+			void *data)
+{
+	struct connection *this = SPA_CONTAINER_OF(conn, struct connection, this);
+	spa_hook_list_append(&this->listener_list, listener, events, data);
+}
+
 static const struct spa_dbus_connection impl_connection = {
 	SPA_VERSION_DBUS_CONNECTION,
 	impl_connection_get,
 	impl_connection_destroy,
+	impl_connection_add_listener,
 };
 
 static struct spa_dbus_connection *
@@ -351,6 +373,7 @@ impl_get_connection(void *object,
 		goto no_event;
 
 	spa_list_init(&conn->source_list);
+	spa_hook_list_init(&conn->listener_list);
 
 	dbus_connection_set_exit_on_disconnect(conn->conn, false);
 	if (!dbus_connection_add_filter(conn->conn, filter_message, conn, NULL))