Datum age_create_barbell_graph()

in src/backend/utils/graph_generation.c [231:351]

• 78 lines of code
• 8 McCabe index (conditional complexity)

Datum age_create_barbell_graph(PG_FUNCTION_ARGS)
{
    FunctionCallInfo arguments;
    Oid graph_oid;
    Name graph_name;
    char* graph_name_str;

    int64 start_node_index, end_node_index, nextval;

    Name node_label_name = NULL;
    int32 node_label_id;
    char* node_label_str;

    Name edge_label_name;
    int32 edge_label_id;
    char* edge_label_str;

    graphid object_graph_id;
    graphid start_node_graph_id;
    graphid end_node_graph_id;

    graph_cache_data* graph_cache;
    label_cache_data* edge_cache;

    agtype* properties = NULL;

    arguments = fcinfo;

    /* Checking for possible NULL arguments */
    /* Name graph_name */
    if (PG_ARGISNULL(0))
    {
        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                        errmsg("Graph name cannot be NULL")));
    }

    graph_name = PG_GETARG_NAME(0);
    graph_name_str = NameStr(*graph_name);

    /* int graph size (number of nodes in each complete graph) */
    if (PG_ARGISNULL(1) && PG_GETARG_INT32(1) < 3)
    {
        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                errmsg("Graph size cannot be NULL or lower than 3")));
    }

    /*
     * int64 bridge_size: currently only stays at zero.
     * to do: implement bridge with variable number of nodes.
     */
    if (PG_ARGISNULL(2) || PG_GETARG_INT32(2) < 0 )
    {
        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                errmsg("Bridge size cannot be NULL or lower than 0")));
    }

    /* node label: if null, gets default label, which is "_ag_label_vertex" */
    if (PG_ARGISNULL(3))
    {
        namestrcpy(node_label_name, AG_DEFAULT_LABEL_VERTEX);
    }
    else
    {
        node_label_name = PG_GETARG_NAME(3);
    }
    node_label_str = NameStr(*node_label_name);

    /* Name edge_label */
    if (PG_ARGISNULL(5))
    {
        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                errmsg("edge label can not be NULL")));
    }

    edge_label_name = PG_GETARG_NAME(5);
    edge_label_str = NameStr(*edge_label_name);


    /* create two separate complete graphs */
    DirectFunctionCall4(create_complete_graph, arguments->args[0].value,
                                               arguments->args[1].value,
                                               arguments->args[5].value,
                                               arguments->args[3].value);
    DirectFunctionCall4(create_complete_graph, arguments->args[0].value,
                                               arguments->args[1].value,
                                               arguments->args[5].value,
                                               arguments->args[3].value);

    graph_oid = get_graph_oid(graph_name_str);
    node_label_id = get_label_id(node_label_str, graph_oid);
    edge_label_id = get_label_id(edge_label_str, graph_oid);

    /*
     * Fetching caches to get next values for graph id's, and access nodes
     * to be connected with edges.
     */
    graph_cache = search_graph_name_cache(graph_name_str);
    edge_cache = search_label_name_graph_cache(edge_label_str,graph_oid);

    /* connect a node from each graph */
    /* first created node, from the first complete graph */
    start_node_index = 1;
    /* last created node, second graph */
    end_node_index = arguments->args[1].value*2;

    /* next index to be assigned to a node or edge */
    nextval = get_nextval_internal(graph_cache, edge_cache);

    /* build the graph id's of the edge to be created */
    object_graph_id = make_graphid(edge_label_id, nextval);
    start_node_graph_id = make_graphid(node_label_id, start_node_index);
    end_node_graph_id = make_graphid(node_label_id, end_node_index);
    properties = create_empty_agtype();

    /* connect two nodes */
    insert_edge_simple(graph_oid, edge_label_str,
                       object_graph_id, start_node_graph_id,
                       end_node_graph_id, properties);

    PG_RETURN_VOID();
}