static librdf_stream*
librdf_storage_tstore_serialise(librdf_storage* storage)
{
librdf_storage_tstore_instance* context=(librdf_storage_tstore_instance*)storage->instance;
librdf_storage_tstore_serialise_stream_context* scontext;
librdf_stream* stream;
scontext=(librdf_storage_tstore_serialise_stream_context*)LIBRDF_CALLOC(librdf_storage_tstore_serialise_stream_context, 1, sizeof(librdf_storage_tstore_serialise_stream_context));
if(!scontext)
return NULL;
scontext->storage=storage;
librdf_storage_add_reference(scontext->storage);
scontext->result=rs_find_all_resources(context->rdfsql, 0, context->model);
if(!scontext->result)
/* empty */
scontext->triple=NULL;
else
scontext->triple=rs_next_triple(scontext->result);
stream=librdf_new_stream(storage->world,
(void*)scontext,
&librdf_storage_tstore_serialise_end_of_stream,
&librdf_storage_tstore_serialise_next_statement,
&librdf_storage_tstore_serialise_get_statement,
&librdf_storage_tstore_serialise_finished);
if(!stream) {
librdf_storage_tstore_serialise_finished((void*)scontext);
return NULL;
}
return stream;
}
static librdf_stream*
librdf_query_rasqal_results_as_stream(librdf_query_results* query_results)
{
librdf_query *query=query_results->query;
librdf_query_rasqal_context *context=(librdf_query_rasqal_context*)query->context;
librdf_query_rasqal_stream_context* scontext;
librdf_stream *stream;
if(!context->results)
return NULL;
scontext = LIBRDF_CALLOC(librdf_query_rasqal_stream_context*, 1,
sizeof(*scontext));
if(!scontext)
return NULL;
scontext->query=query;
scontext->qcontext=context;
librdf_query_rasqal_query_results_update_statement(scontext);
stream=librdf_new_stream(query->world,
(void*)scontext,
&librdf_query_rasqal_query_results_end_of_stream,
&librdf_query_rasqal_query_results_next_statement,
&librdf_query_rasqal_query_results_get_statement,
&librdf_query_rasqal_query_results_finished);
if(!stream) {
librdf_query_rasqal_query_results_finished((void*)scontext);
return NULL;
}
return stream;
}
/**
* librdf_storage_tstore_find_statements:
* @storage: the storage
* @statement: the statement to match
*
* .
*
* Return a stream of statements matching the given statement (or
* all statements if NULL). Parts (subject, predicate, object) of the
* statement can be empty in which case any statement part will match that.
* Uses #librdf_statement_match to do the matching.
*
* Return value: a #librdf_stream or NULL on failure
**/
static librdf_stream*
librdf_storage_tstore_find_statements(librdf_storage* storage, librdf_statement* statement)
{
librdf_storage_tstore_instance* context=(librdf_storage_tstore_instance*)storage->instance;
librdf_storage_tstore_find_stream_context* scontext;
librdf_stream* stream;
rs_triple* triple;
rs_obj_type type;
statement=librdf_new_statement_from_statement(statement);
if(!statement)
return NULL;
scontext=(librdf_storage_tstore_find_stream_context*)LIBRDF_CALLOC(librdf_storage_tstore_find_stream_context, 1, sizeof(librdf_storage_tstore_find_stream_context));
if(!scontext)
return NULL;
scontext->storage=storage;
librdf_storage_add_reference(scontext->storage);
triple=librdf_storage_tstore_statement_as_rs_triple(statement);
scontext->search_triple=triple;
if(triple->object)
type=(triple->literal ? ObjLiteral: ObjURI);
else
type=ObjAny;
scontext->result=rs_find_triples(context->rdfsql,
triple->subject,
triple->predicate,
triple->object,
type,
0,
context->model);
if(!scontext->result)
/* empty */
scontext->triple=NULL;
else
scontext->triple=rs_next_triple(scontext->result);
stream=librdf_new_stream(storage->world,
(void*)scontext,
&librdf_storage_tstore_find_end_of_stream,
&librdf_storage_tstore_find_next_statement,
&librdf_storage_tstore_find_get_statement,
&librdf_storage_tstore_find_finished);
if(!stream) {
librdf_storage_tstore_find_finished((void*)scontext);
return NULL;
}
return stream;
}
/**
* librdf_new_stream_from_node_iterator:
* @iterator: #librdf_iterator of #librdf_node objects
* @statement: #librdf_statement prototype with one NULL node space
* @field: node part of statement
*
* Constructor - create a new #librdf_stream from an iterator of nodes.
*
* Creates a new #librdf_stream using the passed in #librdf_iterator
* which generates a series of #librdf_node objects. The resulting
* nodes are then inserted into the given statement and returned.
* The field attribute indicates which statement node is being generated.
*
* Return value: a new #librdf_stream object or NULL on failure
**/
librdf_stream*
librdf_new_stream_from_node_iterator(librdf_iterator* iterator,
librdf_statement* statement,
librdf_statement_part field)
{
librdf_stream_from_node_iterator_stream_context *scontext;
librdf_stream *stream;
scontext=(librdf_stream_from_node_iterator_stream_context*)LIBRDF_CALLOC(librdf_stream_from_node_iterator_stream_context, 1, sizeof(librdf_stream_from_node_iterator_stream_context));
if(!scontext)
return NULL;
/* copy the prototype statement */
statement=librdf_new_statement_from_statement(statement);
if(!statement) {
LIBRDF_FREE(librdf_stream_from_node_iterator_stream_context, scontext);
return NULL;
}
scontext->iterator=iterator;
scontext->current=statement;
scontext->field=field;
stream=librdf_new_stream(iterator->world,
(void*)scontext,
&librdf_stream_from_node_iterator_end_of_stream,
&librdf_stream_from_node_iterator_next_statement,
&librdf_stream_from_node_iterator_get_statement,
&librdf_stream_from_node_iterator_finished);
if(!stream) {
librdf_stream_from_node_iterator_finished((void*)scontext);
return NULL;
}
return stream;
}
static librdf_stream*
librdf_storage_trees_serialise_range(librdf_storage* storage, librdf_statement* range)
{
librdf_storage_trees_instance* context=(librdf_storage_trees_instance*)storage->instance;
librdf_storage_trees_serialise_stream_context* scontext;
librdf_stream* stream;
int filter = 0;
scontext=(librdf_storage_trees_serialise_stream_context*)LIBRDF_CALLOC(librdf_storage_trees_serialise_stream_context, 1, sizeof(librdf_storage_trees_serialise_stream_context));
if(!scontext)
return NULL;
scontext->iterator = NULL;
/* ?s ?p ?o */
if (!range || (!range->subject && !range->predicate && !range->object)) {
scontext->iterator=librdf_avltree_get_iterator_start(storage->world, context->graph->spo_tree,
NULL, NULL);
if (range) {
librdf_free_statement(range);
range=NULL;
}
/* s ?p o */
} else if (range->subject && !range->predicate && range->object) {
if (context->index_sop)
scontext->iterator=librdf_avltree_get_iterator_start(storage->world, context->graph->sop_tree,
range, librdf_storage_trees_avl_free);
else
filter=1;
/* s _ _ */
} else if (range->subject) {
scontext->iterator=librdf_avltree_get_iterator_start(storage->world, context->graph->spo_tree,
range, librdf_storage_trees_avl_free);
/* ?s _ o */
} else if (range->object) {
if (context->index_ops)
scontext->iterator=librdf_avltree_get_iterator_start(storage->world, context->graph->ops_tree,
range, librdf_storage_trees_avl_free);
else
filter=1;
/* ?s p ?o */
} else { /* range->predicate != NULL */
if (context->index_pso)
scontext->iterator=librdf_avltree_get_iterator_start(storage->world, context->graph->pso_tree,
range, librdf_storage_trees_avl_free);
else
filter=1;
}
/* If filter is set, we're missing the required index.
* Iterate over the entire model and filter the stream.
* (With a fully indexed store, this will never happen) */
if (filter) {
scontext->iterator=librdf_avltree_get_iterator_start(storage->world, context->graph->spo_tree,
range, librdf_storage_trees_avl_free);
}
#ifdef RDF_STORAGE_TREES_WITH_CONTEXTS
scontext->context_node=NULL;
#endif
if(!scontext->iterator) {
LIBRDF_FREE(librdf_storage_trees_serialise_stream_context, scontext);
return librdf_new_empty_stream(storage->world);
}
scontext->storage=storage;
librdf_storage_add_reference(scontext->storage);
stream=librdf_new_stream(storage->world,
(void*)scontext,
&librdf_storage_trees_serialise_end_of_stream,
&librdf_storage_trees_serialise_next_statement,
&librdf_storage_trees_serialise_get_statement,
&librdf_storage_trees_serialise_finished);
if(!stream) {
librdf_storage_trees_serialise_finished((void*)scontext);
return NULL;
}
if(filter) {
if(librdf_stream_add_map(stream, &librdf_stream_statement_find_map, NULL, (void*)range)) {
/* error - stream_add_map failed */
librdf_free_stream(stream);
stream=NULL;
}
}
return stream;
}
/**
* librdf_storage_cassandra_find_statements:
* @storage: the storage
* @statement: the statement to match
*
* .
*
* Return a stream of statements matching the given statement (or
* all statements if NULL). Parts (subject, predicate, object) of the
* statement can be empty in which case any statement part will match that.
* Uses #librdf_statement_match to do the matching.
*
* Return value: a #librdf_stream or NULL on failure
**/
static librdf_stream*
librdf_storage_cassandra_find_statements(librdf_storage* storage,
librdf_statement* statement)
{
librdf_storage_cassandra_instance* context;
cassandra_results_stream* scontext;
librdf_stream* stream;
char* s;
char* p;
char* o;
char* c;
context = (librdf_storage_cassandra_instance*)storage->instance;
scontext =
LIBRDF_CALLOC(cassandra_results_stream*, 1, sizeof(*scontext));
if(!scontext)
return NULL;
scontext->storage = storage;
librdf_storage_add_reference(scontext->storage);
scontext->cassandra_context = context;
statement_helper(storage, statement, 0, &s, &p, &o, &c);
#ifdef DEBUG
fprintf(stderr, "Query: ");
if (s)
fprintf(stderr, "s=%s ", s);
if (p)
fprintf(stderr, "p=%s ", p);
if (o)
fprintf(stderr, "o=%s ", o);
fprintf(stderr, "\n");
#endif
typedef CassStatement* (*query_function)(const char* s, const char* p,
const char* o);
query_function functions[8] = {
&cassandra_query_, /* ??? */
&cassandra_query_s, /* S?? */
&cassandra_query_p, /* ?P? */
&cassandra_query_sp, /* SP? */
&cassandra_query_o, /* ??O */
&cassandra_query_so, /* S?O */
&cassandra_query_po, /* ?PO */
&cassandra_query_spo /* SPO */
};
/* This creates an index into the function table, depending on input
terms. */
int num = 0;
if (o) num += 4;
if (p) num += 2;
if (s) num++;
index_type tp;
query_function fn = functions[num];
CassStatement* stmt = (*fn)(s, p, o);
cass_statement_set_paging_size(stmt, 1000);
if (s) free(s);
if (p) free(p);
if (o) free(o);
CassFuture* future = cass_session_execute(context->session, stmt);
CassError rc = cass_future_error_code(future);
if (rc != CASS_OK) {
fprintf(stderr, "Cassandra: %s\n", cass_error_desc(rc));
const char* msg;
size_t msg_len;
cass_future_error_message(future, &msg, &msg_len);
fprintf(stderr, "Cassandra: %*s\n", msg_len, msg);
cass_future_free(future);
return 0;
}
const CassResult* result = cass_future_get_result(future);
cass_future_free(future);
CassIterator* iter = cass_iterator_from_result(result);
scontext->stmt = stmt;
scontext->result = result;
scontext->iter = iter;
scontext->more_pages = cass_result_has_more_pages(result);
scontext->at_end = !cass_iterator_next(scontext->iter);
stream =
librdf_new_stream(storage->world,
(void*)scontext,
&cassandra_results_stream_end_of_stream,
&cassandra_results_stream_next_statement,
&cassandra_results_stream_get_statement,
&cassandra_results_stream_finished);
if(!stream) {
cassandra_results_stream_finished((void*)scontext);
return NULL;
}
return stream;
}
