Datum drop_label()

in src/backend/commands/label_commands.c [749:836]
72 lines of code
8 McCabe index (conditional complexity)

Datum drop_label(PG_FUNCTION_ARGS)
{
    Name graph_name;
    Name label_name;
    bool force;
    char *graph_name_str;
    graph_cache_data *cache_data;
    Oid graph_oid;
    Oid nsp_id;
    char *label_name_str;
    Oid label_relation;
    char *schema_name;
    char *rel_name;
    List *qname;

    if (PG_ARGISNULL(0))
    {
        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                        errmsg("graph name must not be NULL")));
    }
    if (PG_ARGISNULL(1))
    {
        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                        errmsg("label name must not be NULL")));
    }
    graph_name = PG_GETARG_NAME(0);
    label_name = PG_GETARG_NAME(1);
    force = PG_GETARG_BOOL(2);

    graph_name_str = NameStr(*graph_name);
    cache_data = search_graph_name_cache(graph_name_str);
    if (!cache_data)
    {
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_SCHEMA),
                 errmsg("graph \"%s\" does not exist", graph_name_str)));
    }
    graph_oid = cache_data->oid;
    nsp_id = cache_data->namespace;

    label_name_str = NameStr(*label_name);
    label_relation = get_label_relation(label_name_str, graph_oid);
    if (!OidIsValid(label_relation))
    {
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_TABLE),
                 errmsg("label \"%s\" does not exist", label_name_str)));
    }

    if (force)
    {
        ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                        errmsg("force option is not supported yet")));
    }

    /* validate schema_name */
    schema_name = get_namespace_name(nsp_id);
    if (schema_name == NULL)
    {
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_TABLE),
                 errmsg("schema_name not found for namespace id \"%d\"",
                        nsp_id)));
    }

    /* validate rel_name */
    rel_name = get_rel_name(label_relation);
    if (rel_name == NULL)
    {
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_TABLE),
                 errmsg("rel_name not found for label \"%s\"",
                        label_name_str)));
    }

    /* build qualified name */
    qname = list_make2(makeString(schema_name), makeString(rel_name));

    remove_relation(qname);
    /* CommandCounterIncrement() is called in performDeletion() */

    /* delete_label() will be called in object_access() */

    ereport(NOTICE, (errmsg("label \"%s\".\"%s\" has been dropped",
                            graph_name_str, label_name_str)));

    PG_RETURN_VOID();
}