Collect useless graph's connections

[babeltrace.git] / lib / graph / connection.c

diff --git a/lib/graph/connection.c b/lib/graph/connection.c
index feed59556247c562c40d2149cf38cae7e20263f7..7bdbee6227ff3656eedc3e9959f2d720fea01644 100644 (file)
--- a/lib/graph/connection.c
+++ b/lib/graph/connection.c
@@ -82,6 +82,45 @@ void bt_connection_destroy(struct bt_object *obj)
        g_free(connection);
 }
 
+static
+void bt_connection_try_remove_from_graph(struct bt_connection *connection)
+{
+       void *graph = bt_object_borrow_parent(&connection->base);
+
+       if (connection->base.ref_count.count > 0 ||
+                       connection->downstream_port ||
+                       connection->upstream_port ||
+                       connection->iterators->len > 0) {
+               return;
+       }
+
+       /*
+        * At this point we know that:
+        *
+        * 1. The connection is dead (ports were disconnected).
+        * 2. All the notification iterators that this connection
+        *    created, if any, are finalized.
+        * 3. The connection's reference count is 0, so only the
+        *    parent (graph) owns this connection after this call.
+        *
+        * In other words, no other object than the graph knows this
+        * connection.
+        *
+        * It is safe to remove the connection from the graph, therefore
+        * destroying it.
+        */
+       bt_graph_remove_connection(graph, connection);
+}
+
+static
+void bt_connection_parent_is_owner(struct bt_object *obj)
+{
+       struct bt_connection *connection = container_of(obj,
+                       struct bt_connection, base);
+
+       bt_connection_try_remove_from_graph(connection);
+}
+
 struct bt_connection *bt_connection_from_private_connection(
                struct bt_private_connection *private_connection)
 {
@@ -109,6 +148,8 @@ struct bt_connection *bt_connection_create(
        }
 
        bt_object_init(connection, bt_connection_destroy);
+       bt_object_set_parent_is_owner_listener(connection,
+               bt_connection_parent_is_owner);
        connection->iterators = g_ptr_array_new();
        if (!connection->iterators) {
                BT_PUT(connection);
@@ -132,7 +173,8 @@ void bt_connection_disconnect_ports(struct bt_connection *conn)
        struct bt_component *upstream_comp = NULL;
        struct bt_port *downstream_port = conn->downstream_port;
        struct bt_port *upstream_port = conn->upstream_port;
-       struct bt_graph *graph = (void *) bt_object_get_parent(conn);
+       struct bt_graph *graph = (void *) bt_object_borrow_parent(conn);
+       size_t i;
 
        if (downstream_port) {
                downstream_comp = bt_port_get_component(downstream_port);
@@ -160,7 +202,28 @@ void bt_connection_disconnect_ports(struct bt_connection *conn)
                downstream_comp, upstream_port, downstream_port);
        bt_put(downstream_comp);
        bt_put(upstream_comp);
-       bt_put(graph);
+
+       /*
+        * Because this connection is dead, finalize (cancel) each
+        * notification iterator created from it.
+        */
+       for (i = 0; i < conn->iterators->len; i++) {
+               struct bt_notification_iterator *iterator =
+                       g_ptr_array_index(conn->iterators, i);
+
+               bt_notification_iterator_finalize(iterator);
+
+               /*
+                * Make sure this iterator does not try to remove itself
+                * from this connection's iterators on destruction
+                * because this connection won't exist anymore.
+                */
+               bt_notification_iterator_set_connection(iterator,
+                       NULL);
+       }
+
+       g_ptr_array_set_size(conn->iterators, 0);
+       bt_connection_try_remove_from_graph(conn);
 }
 
 struct bt_port *bt_connection_get_upstream_port(
@@ -282,4 +345,5 @@ void bt_connection_remove_iterator(struct bt_connection *conn,
                struct bt_notification_iterator *iterator)
 {
        g_ptr_array_remove(conn->iterators, iterator);
+       bt_connection_try_remove_from_graph(conn);
 }