bool RdfStorePrivate::ExecuteBooleanQuery(const std::string& query) const
{
const std::string completeQuery = this->PrependPrefixes(query);
librdf_query* rdfQuery = librdf_new_query(m_World, "sparql", nullptr, (const unsigned char*) completeQuery.c_str(), nullptr);
if (!rdfQuery)
{
mitkThrow() << "failed to create query object";
}
librdf_query_results* results = librdf_query_execute(rdfQuery, m_Model);
if (!results)
{
librdf_free_query(rdfQuery);
mitkThrow() << "SPARQL syntax error";
}
if (!librdf_query_results_is_boolean(results))
{
librdf_free_query_results(results);
librdf_free_query(rdfQuery);
mitkThrow() << "unexpected result type error: tried to request a boolean result with a non-boolean query";
}
int rawResult = librdf_query_results_get_boolean(results);
bool booleanResult;
if (rawResult > 0)
{
booleanResult = true;
}
else if (rawResult == 0)
{
booleanResult = false;
}
else
{
mitkThrow() << "error while retrieving result";
}
librdf_free_query_results(results);
librdf_free_query(rdfQuery);
return booleanResult;
}
bool
slv2_port_supports_event(SLV2Plugin p,
SLV2Port port,
SLV2Value event)
{
assert(event);
char* query = slv2_strjoin(
"ASK WHERE {\n"
"<", slv2_value_as_uri(p->plugin_uri), "> lv2:port ?port ."
"?port lv2:symbol \"", slv2_value_as_string(port->symbol), "\";\n",
" lv2ev:supportsEvent <", event, "> .\n"
"}", NULL);
librdf_query_results* results = slv2_plugin_query(p, query);
assert(librdf_query_results_is_boolean(results));
const bool ret = librdf_query_results_get_boolean(results);
free(query);
librdf_free_query_results(results);
return ret;
}
int
print_query_results(librdf_world* world, librdf_model* model, librdf_query_results *results)
{
int i;
char *name;
librdf_stream* stream;
librdf_serializer* serializer;
const char *query_graph_serializer_syntax_name="rdfxml";
if(librdf_query_results_is_bindings(results)) {
fprintf(stdout, ": Query returned bindings results:\n");
while(!librdf_query_results_finished(results)) {
fputs("result: [", stdout);
for(i=0; i<librdf_query_results_get_bindings_count(results); i++) {
librdf_node *value=librdf_query_results_get_binding_value(results, i);
name=(char*)librdf_query_results_get_binding_name(results, i);
if(i>0)
fputs(", ", stdout);
fprintf(stdout, "%s=", name);
if(value) {
librdf_node_print(value, stdout);
librdf_free_node(value);
} else
fputs("NULL", stdout);
}
fputs("]\n", stdout);
librdf_query_results_next(results);
}
fprintf(stdout, ": Query returned %d results\n", librdf_query_results_get_count(results));
} else if(librdf_query_results_is_boolean(results)) {
fprintf(stdout, ": Query returned boolean result: %s\n", librdf_query_results_get_boolean(results) ? "true" : "false");
} else if(librdf_query_results_is_graph(results)) {
librdf_storage* tmp_storage;
librdf_model* tmp_model;
tmp_storage=librdf_new_storage(world, NULL, NULL, NULL);
tmp_model=librdf_new_model(world, tmp_storage, NULL);
fprintf(stdout, ": Query returned graph result:\n");
stream=librdf_query_results_as_stream(results);
if(!stream) {
fprintf(stderr, ": Failed to get query results graph\n");
return -1;
}
librdf_model_add_statements(tmp_model, stream);
librdf_free_stream(stream);
fprintf(stdout, ": Total %d triples\n", librdf_model_size(model));
serializer=librdf_new_serializer(world, query_graph_serializer_syntax_name, NULL, NULL);
if(!serializer) {
fprintf(stderr, ": Failed to create serializer type %s\n", query_graph_serializer_syntax_name);
return -1;
}
librdf_serializer_serialize_model_to_file_handle(serializer, stdout, NULL, tmp_model);
librdf_free_serializer(serializer);
librdf_free_model(tmp_model);
librdf_free_storage(tmp_storage);
} else {
fprintf(stdout, ": Query returned unknown result format\n");
return -1;
}
return 0;
}
