struct bt_graph *downstream_graph = NULL;
struct bt_component *upstream_component = NULL;
struct bt_component *downstream_component = NULL;
- struct bt_connection *existing_conn = NULL;
enum bt_component_status component_status;
bool upstream_was_already_in_graph;
bool downstream_was_already_in_graph;
- int components_to_remove = 0;
- int i;
if (!graph || !upstream_port || !downstream_port) {
goto end;
}
/* Ensure that both ports are currently unconnected. */
- existing_conn = bt_port_get_connection(upstream_port);
- bt_put(existing_conn);
- if (existing_conn) {
+ if (bt_port_is_connected(upstream_port)) {
fprintf(stderr, "Upstream port is already connected\n");
goto end;
}
- existing_conn = bt_port_get_connection(downstream_port);
- bt_put(existing_conn);
- if (existing_conn) {
+ if (bt_port_is_connected(downstream_port)) {
fprintf(stderr, "Downstream port is already connected\n");
goto end;
}
}
downstream_was_already_in_graph = (graph == downstream_graph);
+ /*
+ * At this point the ports are not connected yet. Both
+ * components need to accept an eventual connection to their
+ * port by the other port before we continue.
+ */
+ component_status = bt_component_accept_port_connection(
+ upstream_component, upstream_port, downstream_port);
+ if (component_status != BT_COMPONENT_STATUS_OK) {
+ goto error;
+ }
+ component_status = bt_component_accept_port_connection(
+ downstream_component, downstream_port, upstream_port);
+ if (component_status != BT_COMPONENT_STATUS_OK) {
+ goto error;
+ }
+
connection = bt_connection_create(graph, upstream_port,
downstream_port);
if (!connection) {
}
/*
- * The graph is now the parent of these components which garantees their
- * existence for the duration of the graph's lifetime.
+ * The graph is now the parent of these components which
+ * garantees their existence for the duration of the graph's
+ * lifetime.
*/
/*
- * The components and connection are added to the graph before
- * invoking the `accept_port_connection` method in order to make
- * them visible to the components during the method's
- * invocation.
+ * Notify both components that their port is connected.
*/
- component_status = bt_component_accept_port_connection(
- upstream_component, upstream_port, downstream_port);
- if (component_status != BT_COMPONENT_STATUS_OK) {
- goto error_rollback;
- }
- component_status = bt_component_accept_port_connection(
- downstream_component, downstream_port, upstream_port);
- if (component_status != BT_COMPONENT_STATUS_OK) {
- goto error_rollback;
- }
+ bt_component_port_connected(upstream_component, upstream_port,
+ downstream_port);
+ bt_component_port_connected(downstream_component, downstream_port,
+ upstream_port);
/*
- * Both components accepted the connection. Notify the graph's
- * creator that both ports are connected.
+ * Notify the graph's creator that both ports are connected.
*/
bt_graph_notify_ports_connected(graph, upstream_port, downstream_port);
bt_put(upstream_component);
bt_put(downstream_component);
return connection;
-error_rollback:
- /*
- * Remove newly-added components from the graph, being careful
- * not to remove a component that was already present in the graph
- * and is connected to other components.
- */
- components_to_remove += upstream_was_already_in_graph ? 0 : 1;
- components_to_remove += downstream_was_already_in_graph ? 0 : 1;
- if (!downstream_was_already_in_graph) {
- if (bt_component_get_class_type(downstream_component) ==
- BT_COMPONENT_CLASS_TYPE_SINK) {
- g_queue_pop_tail(graph->sinks_to_consume);
- }
- }
- /* Remove newly created connection. */
- g_ptr_array_set_size(graph->connections,
- graph->connections->len - 1);
-
- /*
- * Remove newly added components.
- *
- * Note that this is a tricky situation. The graph, being the parent
- * of the components, does not hold a reference to them. Normally,
- * components are destroyed right away when the graph is released since
- * the graph, being their parent, bounds their lifetime
- * (see doc/ref-counting.md).
- *
- * In this particular case, we must take a number of steps:
- * 1) unset the components' parent to rollback the initial state of
- * the components being connected.
- * Note that the reference taken by the component on its graph is
- * released by the set_parent call.
- * 2) set the pointer in the components array to NULL so that the
- * destruction function called on the array's resize in invoked on
- * NULL (no effect),
- *
- * NOTE: Point #1 assumes that *something* holds a reference to both
- * components being connected. The fact that a reference is being
- * held to a component means that it must hold a reference to its
- * parent to prevent the parent from being destroyed (again, refer
- * to doc/red-counting.md). This reference to a component is
- * most likely being held *transitively* by the caller which holds
- * a reference to both ports (a port has its component as a
- * parent).
- *
- * This assumes that a graph is not connecting components by
- * itself while not holding a reference to the ports/components
- * being connected (i.e. "cheating" by using internal APIs).
- */
- for (i = 0; i < components_to_remove; i++) {
- struct bt_component *component = g_ptr_array_index(
- graph->components, graph->components->len - 1);
-
- bt_component_set_graph(component, NULL);
- g_ptr_array_index(graph->components,
- graph->components->len - 1) = NULL;
- g_ptr_array_set_size(graph->components,
- graph->components->len - 1);
- }
- /* NOTE: Resizing the ptr_arrays invokes the destruction of the elements. */
- goto end;
error:
BT_PUT(upstream_component);
BT_PUT(downstream_component);
projects / babeltrace.git / blobdiff