static int
rasqal_graph_rowsource_init(rasqal_rowsource* rowsource, void *user_data)
{
rasqal_graph_rowsource_context *con;
raptor_sequence* seq;
con = (rasqal_graph_rowsource_context*)user_data;
seq = rasqal_query_get_data_graph_sequence(rowsource->query);
if(!seq)
return 1;
con->dg_size = raptor_sequence_size(seq);
con->finished = 0;
con->dg_offset = -1;
con->offset = 0;
/* Do not care if finished at this stage (it is not an
* error). rasqal_graph_rowsource_read_row() will deal with
* returning NULL for an empty result.
*/
rasqal_graph_next_dg(con);
return 0;
}
static rasqal_row*
rasqal_graph_rowsource_read_row(rasqal_rowsource* rowsource, void *user_data)
{
rasqal_graph_rowsource_context *con;
rasqal_row* row = NULL;
con = (rasqal_graph_rowsource_context*)user_data;
if(con->finished)
return NULL;
while(1) {
row = rasqal_rowsource_read_row(con->rowsource);
if(row)
break;
if(rasqal_graph_next_dg(con)) {
con->finished = 1;
break;
}
if(rasqal_rowsource_reset(con->rowsource)) {
con->finished = 1;
break;
}
}
/* If a row is returned, put the GRAPH variable value as first literal */
if(row) {
rasqal_row* nrow;
int i;
nrow = rasqal_new_row_for_size(rowsource->world, 1 + row->size);
if(!nrow) {
rasqal_free_row(row);
row = NULL;
} else {
nrow->rowsource = rowsource;
nrow->offset = row->offset;
/* Put GRAPH variable value (or NULL) first in result row */
nrow->values[0] = rasqal_new_literal_from_literal(con->var->value);
/* Copy (size-1) remaining variables from input row */
for(i = 0; i < row->size; i++)
nrow->values[i + 1] = rasqal_new_literal_from_literal(row->values[i]);
rasqal_free_row(row);
row = nrow;
}
}
return row;
}
static int
rasqal_graph_rowsource_reset(rasqal_rowsource* rowsource, void *user_data)
{
rasqal_graph_rowsource_context *con;
con = (rasqal_graph_rowsource_context*)user_data;
con->finished = 0;
con->dg_offset = -1;
con->offset = 0;
rasqal_graph_next_dg(con);
return rasqal_rowsource_reset(con->rowsource);
}
