/**
* rasqal_new_service_rowsource:
* @world: world object
* @query: query object
* @service_uri: service URI
* @query_string: query to send to service
* @data_graphs: sequence of data graphs (or NULL)
* @rs_flags: service rowsource flags
*
* INTERNAL - create a new rowsource that takes rows from a service
*
* All arguments are copied.
*
* Return value: new rowsource or NULL on failure
*/
rasqal_rowsource*
rasqal_new_service_rowsource(rasqal_world *world, rasqal_query* query,
raptor_uri* service_uri,
const unsigned char* query_string,
raptor_sequence* data_graphs,
unsigned int rs_flags)
{
rasqal_service_rowsource_context* con = NULL;
rasqal_service* svc = NULL;
int flags = 0;
int silent = (rs_flags & RASQAL_ENGINE_BITFLAG_SILENT);
if(!world || !query_string)
goto fail;
svc = rasqal_new_service(query->world, service_uri, query_string,
data_graphs);
if(!svc) {
if(!silent)
goto fail;
/* Silent errors so tidy up and return empty rowsource */
RASQAL_FREE(cstring, query_string);
if(data_graphs)
raptor_free_sequence(data_graphs);
return rasqal_new_empty_rowsource(world, query);
}
con = RASQAL_CALLOC(rasqal_service_rowsource_context*, 1, sizeof(*con));
if(!con)
goto fail;
con->svc = svc;
con->query = query;
con->flags = rs_flags;
return rasqal_new_rowsource_from_handler(world, query,
con,
&rasqal_service_rowsource_handler,
query->vars_table,
flags);
fail:
if(svc)
rasqal_free_service(svc);
if(con)
RASQAL_FREE(rasqal_service_rowsource_context, con);
if(query_string)
RASQAL_FREE(cstring, query_string);
if(data_graphs)
raptor_free_sequence(data_graphs);
return NULL;
}
static rasqal_rowsource*
rasqal_algebra_filter_algebra_node_to_rowsource(rasqal_engine_algebra_data* execution_data,
rasqal_algebra_node* node,
rasqal_engine_error *error_p)
{
rasqal_query *query = execution_data->query;
rasqal_rowsource *rs;
if(node->node1) {
rs = rasqal_algebra_node_to_rowsource(execution_data, node->node1, error_p);
} else {
rs = rasqal_new_empty_rowsource(query->world, query);
}
if(!rs || *error_p)
return NULL;
return rasqal_new_filter_rowsource(query->world, query, rs, node->expr);
}
static int
rasqal_service_rowsource_init(rasqal_rowsource* rowsource, void *user_data)
{
rasqal_service_rowsource_context* con;
con = (rasqal_service_rowsource_context*)user_data;
con->rowsource = rasqal_service_execute_as_rowsource(con->svc,
con->query->vars_table);
if(!con->rowsource) {
/* Silent errors return an empty rowsource */
if(con->flags & RASQAL_ENGINE_BITFLAG_SILENT) {
con->rowsource = rasqal_new_empty_rowsource(con->query->world,
con->query);
return 0;
}
return 1;
}
return 0;
}
static rasqal_rowsource*
rasqal_algebra_graph_algebra_node_to_rowsource(rasqal_engine_algebra_data* execution_data,
rasqal_algebra_node* node,
rasqal_engine_error *error_p)
{
rasqal_query *query = execution_data->query;
rasqal_rowsource *rs;
rasqal_literal *graph = node->graph;
rasqal_variable* v;
if(!graph) {
RASQAL_DEBUG1("graph algebra node has NULL graph\n");
return NULL;
}
/*
This code checks that #1-#3 below are present and
then executes parts #1 and #2 here.
The graph rowsource created by rasqal_new_graph_rowsource() executes #3
http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115/#sparqlAlgebraEval
SPARQL Query Language for RDF - Evaluation of a Graph Pattern
#1 if IRI is a graph name in D
eval(D(G), Graph(IRI,P)) = eval(D(D[IRI]), P)
#2 if IRI is not a graph name in D
eval(D(G), Graph(IRI,P)) = the empty multiset
#3 eval(D(G), Graph(var,P)) =
Let R be the empty multiset
foreach IRI i in D
R := Union(R, Join( eval(D(D[i]), P) , Omega(?var->i) )
the result is R
*/
v = rasqal_literal_as_variable(graph);
if(!v && graph->type != RASQAL_LITERAL_URI) {
/* value is neither a variable or URI literal - error */
RASQAL_DEBUG1("graph algebra node is neither variable or URI\n");
return NULL;
}
if(!v && graph->type == RASQAL_LITERAL_URI) {
if(rasqal_query_dataset_contains_named_graph(query, graph->value.uri)) {
/* case #1 - IRI is a graph name in D */
/* Set the origin of all triple patterns inside node->node1 to
* URI graph->value.uri
*
* FIXME - this is a hack. The graph URI should be a parameter
* to all rowsource constructors.
*/
rasqal_algebra_node_set_origin(query, node->node1, graph);
rs = rasqal_algebra_node_to_rowsource(execution_data, node->node1,
error_p);
} else {
/* case #2 - IRI is not a graph name in D - return empty rowsource */
rasqal_free_algebra_node(node->node1);
node->node1 = NULL;
rs = rasqal_new_empty_rowsource(query->world, query);
}
if(!rs || *error_p)
rs = NULL;
return rs;
}
/* case #3 - a variable */
rs = rasqal_algebra_node_to_rowsource(execution_data, node->node1, error_p);
if(!rs || *error_p)
return NULL;
return rasqal_new_graph_rowsource(query->world, query, rs, v);
}
int
main(int argc, char *argv[])
{
const char *program = rasqal_basename(argv[0]);
rasqal_rowsource *rowsource = NULL;
rasqal_world* world = NULL;
rasqal_query* query = NULL;
rasqal_row* row = NULL;
int count;
raptor_sequence* seq = NULL;
int failures = 0;
world = rasqal_new_world();
if(!world || rasqal_world_open(world)) {
fprintf(stderr, "%s: rasqal_world init failed\n", program);
return(1);
}
query = rasqal_new_query(world, "sparql", NULL);
rowsource = rasqal_new_empty_rowsource(world, query);
if(!rowsource) {
fprintf(stderr, "%s: failed to create empty rowsource\n", program);
failures++;
goto tidy;
}
row = rasqal_rowsource_read_row(rowsource);
if(!row) {
fprintf(stderr,
"%s: read_row failed to return a row for an empty rowsource\n",
program);
failures++;
goto tidy;
}
if(row->size) {
fprintf(stderr,
"%s: read_row returned an non-empty row size %d for a empty stream\n",
program, row->size);
failures++;
goto tidy;
}
count = rasqal_rowsource_get_rows_count(rowsource);
if(count != 1) {
fprintf(stderr, "%s: read_rows returned count %d for a empty stream\n",
program, count);
failures++;
goto tidy;
}
rasqal_free_row(row); row = NULL;
rasqal_free_rowsource(rowsource);
/* re-init rowsource */
rowsource = rasqal_new_empty_rowsource(world, query);
seq = rasqal_rowsource_read_all_rows(rowsource);
if(!seq) {
fprintf(stderr, "%s: read_rows returned a NULL seq for a empty stream\n",
program);
failures++;
goto tidy;
}
count = raptor_sequence_size(seq);
if(count != 1) {
fprintf(stderr, "%s: read_rows returned size %d seq for a empty stream\n",
program, count);
failures++;
goto tidy;
}
tidy:
if(row)
rasqal_free_row(row);
if(seq)
raptor_free_sequence(seq);
if(rowsource)
rasqal_free_rowsource(rowsource);
if(query)
rasqal_free_query(query);
if(world)
rasqal_free_world(world);
return failures;
}