[redland-dev] Problem with 'librdf_model_get_arcs_in'

[Maciej Janik]

Hi,

I try to get the whole neighborhood of a resources - all nodes
that it points to and is pointed by.
But 'librdf_model_get_arcs_in' do not return any results
(iterator is empty) and there is assertion error:

rdf_storage.c:847: (librdf_storage_node_stream_to_node_create)
assertion failed: object pointer of type librdf_node is NULL.

Call is:
iter = librdf_model_get_arcs_in(model, currNode);

where 'currNode' is a valid 'librdf_node*' that has some
incoming arcs. I use in-memory hashes model.

Am I using it incorrect or is it not supported by model or bug?

I attach short C program to illustrate the problem.

Thanks for any help.

Maciek
-------------- next part --------------
#include <stdio.h>
#include <redland.h>
#include <string.h>

int main(int argc, char *argv[])
{

	if(argc < 3)
	{
		printf("Usage - loads RDF file to memory and prints neighborhood of given resource \n");
		printf("    %s [rdf_filename] [resource_uri]\n", argv[0]);
		return 0;
	}

    librdf_world* world;
    librdf_storage *storage;
    librdf_model* model;
    librdf_node* arc;
    librdf_node* tg;
    librdf_node* currNode;
    librdf_uri* uri;
    librdf_parser* parser;
    librdf_iterator* iter;
    char* filename;

    world=librdf_new_world();
    librdf_world_open(world);

    storage=librdf_new_storage(world, "hashes", NULL, "hash-type='memory'");
    model=librdf_new_model(world, storage, NULL);

    parser=librdf_new_parser(world,"rdfxml","application/rdf+xml",NULL);
	int len = strlen(argv[1]);

    filename = new char[len+6];
	sprintf(filename, "file:%s", argv[1]);

	printf("Loading RDF data from [%s] file\n", filename);
	uri=librdf_new_uri(world, (const unsigned char*) filename);
    librdf_parser_parse_into_model(parser,uri,uri,model);
	printf("Load success!\n");
	delete[] filename;

    printf("Resource URI <%s>\n", argv[2]);
	currNode = librdf_new_node_from_uri_string(world, (const unsigned char *) argv[2]);

	/*
	 * OUTGOING ARCS - here works OK
	 */
	printf("Looking for outgoing arcs ...\n");
	iter = librdf_model_get_arcs_out(model, currNode);
    printf("Outgoing arcs OK\n");

	while(!librdf_iterator_end(iter))
	{
		arc=(librdf_node*)librdf_iterator_get_object(iter);
		librdf_node_print(arc, stdout);
		printf(" -> ");
		tg = librdf_model_get_target(model, currNode, arc);
		librdf_node_print(tg, stdout);
		printf("\n");
		librdf_iterator_next(iter);
	}

	/*
	 * INCOMING ARCS - where the problem occurs ...
	 */
	printf("Looking for incoming arcs ...\n");
	iter = librdf_model_get_arcs_in(model, currNode);
    printf("Incoming arcs OK\n");

	while(!librdf_iterator_end(iter))
	{
		arc=(librdf_node*)librdf_iterator_get_object(iter);
		librdf_node_print(arc, stdout);
		printf(" <- ");
		tg = librdf_model_get_source(model, arc, currNode);
		librdf_node_print(tg, stdout);
		printf("\n");
		librdf_iterator_next(iter);
	}

	return 0;
}