/* -*- Mode: c; c-basic-offset: 2 -*-
*
* rdf_storage.c - RDF Storage (Triple store) interface
*
* $Id: rdf_storage.c 11461 2006-10-08 06:38:21Z dajobe $
*
* Copyright (C) 2000-2006, David Beckett http://purl.org/net/dajobe/
* Copyright (C) 2000-2005, University of Bristol, UK http://www.bristol.ac.uk/
*
* This package is Free Software and part of Redland http://librdf.org/
*
* It is licensed under the following three licenses as alternatives:
* 1. GNU Lesser General Public License (LGPL) V2.1 or any newer version
* 2. GNU General Public License (GPL) V2 or any newer version
* 3. Apache License, V2.0 or any newer version
*
* You may not use this file except in compliance with at least one of
* the above three licenses.
*
* See LICENSE.html or LICENSE.txt at the top of this package for the
* complete terms and further detail along with the license texts for
* the licenses in COPYING.LIB, COPYING and LICENSE-2.0.txt respectively.
*
*
*/
#ifdef HAVE_CONFIG_H
#include <rdf_config.h>
#endif
#ifdef WIN32
#include <win32_rdf_config.h>
#endif
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <sys/types.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h> /* for abort() as used in errors */
#endif
#include <redland.h>
#include <rdf_storage.h>
#ifndef STANDALONE
/* prototypes for functions implementing get_sources, arcs, targets
* librdf_iterator via conversion from a librdf_stream of librdf_statement
*/
static int librdf_storage_stream_to_node_iterator_is_end(void* iterator);
static int librdf_storage_stream_to_node_iterator_next_method(void* iterator);
static void* librdf_storage_stream_to_node_iterator_get_method(void* iterator, int flags);
static void librdf_storage_stream_to_node_iterator_finished(void* iterator);
/* helper function for creating iterators for get sources, targets, arcs */
static librdf_iterator* librdf_storage_node_stream_to_node_create(librdf_storage* storage, librdf_node* node1, librdf_node *node2, librdf_statement_part want);
/**
* librdf_init_storage:
* @world: redland world object
*
* INTERNAL - Initialise the librdf_storage module.
*
* Initialises and registers all
* compiled storage modules. Must be called before using any of the storage
* factory functions such as librdf_get_storage_factory()
**/
void
librdf_init_storage(librdf_world *world)
{
/* Always have storage memory - must always be the default storage */
librdf_init_storage_list(world);
/* Always have storage list, hashes, file implementations available */
librdf_init_storage_hashes(world);
#ifdef STORAGE_FILE
librdf_init_storage_file(world);
#endif
#ifdef STORAGE_MYSQL
librdf_init_storage_mysql(world);
#endif
#ifdef STORAGE_POSTGRESQL
librdf_init_storage_postgresql(world);
#endif
#ifdef STORAGE_TSTORE
librdf_init_storage_tstore(world);
#endif
#ifdef STORAGE_SQLITE
librdf_init_storage_sqlite(world);
#endif
}
/**
* librdf_finish_storage:
* @world: redland world object
*
* INTERNAL - Terminate the librdf_storage module.
*
**/
void
librdf_finish_storage(librdf_world *world)
{
raptor_free_sequence(world->storages);
world->storages=NULL;
}
/* helper functions */
static void
librdf_free_storage_factory(librdf_storage_factory* factory)
{
LIBRDF_FREE(librdf_storage_factory, factory->name);
LIBRDF_FREE(librdf_storage_factory, factory->label);
LIBRDF_FREE(librdf_storage_factory, factory);
}
/* class methods */
/**
* librdf_storage_register_factory:
* @world: redland world object
* @name: the storage factory name
* @label: the storage factory label
* @factory: pointer to function to call to register the factory
*
* Register a storage factory.
**/
void
librdf_storage_register_factory(librdf_world* world,
const char *name, const char *label,
void (*factory) (librdf_storage_factory*))
{
librdf_storage_factory *storage, *h;
char *name_copy;
char *label_copy;
int i;
#if defined(LIBRDF_DEBUG) && LIBRDF_DEBUG > 1
LIBRDF_DEBUG2("Received registration for storage %s\n", name);
#endif
if(!world->storages)
world->storages=raptor_new_sequence((raptor_sequence_free_handler *)librdf_free_storage_factory, NULL);
for(i=0;
(h=(librdf_storage_factory*)raptor_sequence_get_at(world->storages, i));
i++) {
if(!strcmp(h->name, name)) {
librdf_log(world,
0, LIBRDF_LOG_ERROR, LIBRDF_FROM_STORAGE, NULL,
"storage %s already registered", h->name);
return;
}
}
storage=(librdf_storage_factory*)LIBRDF_CALLOC(librdf_storage_factory, 1,
sizeof(librdf_storage_factory));
if(!storage)
LIBRDF_FATAL1(world, LIBRDF_FROM_STORAGE, "Out of memory");
name_copy=(char*)LIBRDF_CALLOC(cstring, strlen(name)+1, 1);
if(!name_copy) {
LIBRDF_FREE(librdf_storage, storage);
LIBRDF_FATAL1(world, LIBRDF_FROM_STORAGE, "Out of memory");
}
strcpy(name_copy, name);
storage->name=name_copy;
label_copy=(char*)LIBRDF_CALLOC(cstring, strlen(label)+1, 1);
if(!label_copy) {
LIBRDF_FREE(librdf_storage, storage);
LIBRDF_FATAL1(world, LIBRDF_FROM_STORAGE, "Out of memory");
}
strcpy(label_copy, label);
storage->label=label_copy;
/* Call the storage registration function on the new object */
(*factory)(storage);
#if defined(LIBRDF_DEBUG) && LIBRDF_DEBUG > 1
LIBRDF_DEBUG3("%s has context size %d\n", name, storage->context_length);
#endif
raptor_sequence_push(world->storages, storage);
}
/**
* librdf_get_storage_factory:
* @world: redland world object
* @name: the factory name or NULL for the default factory
*
* Get a storage factory by name.
*
* Return value: the factory object or NULL if there is no such factory
**/
librdf_storage_factory*
librdf_get_storage_factory(librdf_world* world, const char *name)
{
librdf_storage_factory *factory;
/* return 1st storage if no particular one wanted - why? */
if(!name) {
factory=(librdf_storage_factory *)raptor_sequence_get_at(world->storages, 0);
if(!factory) {
LIBRDF_DEBUG1("No (default) storages registered\n");
return NULL;
}
} else {
int i;
for(i=0;
(factory=(librdf_storage_factory*)raptor_sequence_get_at(world->storages, i));
i++) {
if(!strcmp(factory->name, name))
break;
}
/* else FACTORY name not found */
if(!factory) {
LIBRDF_DEBUG2("No storage with name %s found\n", name);
return NULL;
}
}
return factory;
}
/**
* librdf_storage_enumerate:
* @world: redland world object
* @counter: index into the list of storages
* @name: pointer to store the name of the storage (or NULL)
* @label: pointer to store syntax readable label (or NULL)
*
* Get information on storages.
*
* Return value: non 0 on failure of if counter is out of range
**/
int
librdf_storage_enumerate(librdf_world* world,
const unsigned int counter,
const char **name, const char **label)
{
librdf_storage_factory *factory;
factory=(librdf_storage_factory*)raptor_sequence_get_at(world->storages,
counter);
if(!factory)
return 1;
if(name)
*name=factory->name;
if(label)
*label=factory->label;
return 0;
}
/**
* librdf_new_storage:
* @world: redland world object
* @storage_name: the storage factory name
* @name: an identifier for the storage
* @options_string: options to initialise storage
*
* Constructor - create a new #librdf_storage object.
*
* The options are encoded as described in librdf_hash_from_string()
* and can be NULL if none are required.
*
* Return value: a new #librdf_storage object or NULL on failure
*
*/
librdf_storage*
librdf_new_storage (librdf_world *world,
const char *storage_name, const char *name,
const char *options_string) {
librdf_storage_factory* factory;
librdf_hash* options_hash;
factory=librdf_get_storage_factory(world, storage_name);
if(!factory)
return NULL;
options_hash=librdf_new_hash(world, NULL);
if(!options_hash)
return NULL;
if(librdf_hash_open(options_hash, NULL, 0, 1, 1, NULL)) {
librdf_free_hash(options_hash);
return NULL;
}
if(librdf_hash_from_string(options_hash, options_string)) {
librdf_free_hash(options_hash);
return NULL;
}
return librdf_new_storage_from_factory(world, factory, name, options_hash);
}
/**
* librdf_new_storage_with_options:
* @world: redland world object
* @storage_name: the storage factory name
* @name: an identifier for the storage
* @options: #librdf_hash of options to use
*
* Constructor - create a new #librdf_storage object.
*
* The options can be NULL if none are required.
*
* Return value: a new #librdf_storage object or NULL on failure
*
*/
librdf_storage*
librdf_new_storage_with_options(librdf_world *world,
const char *storage_name, const char *name,
librdf_hash *options) {
librdf_storage_factory* factory;
librdf_hash* options_hash;
factory=librdf_get_storage_factory(world, storage_name);
if(!factory)
return NULL;
options_hash=librdf_new_hash_from_hash(options);
if(!options_hash)
return NULL;
if(librdf_hash_open(options_hash, NULL, 0, 1, 1, NULL)) {
librdf_free_hash(options_hash);
return NULL;
}
return librdf_new_storage_from_factory(world, factory, name, options_hash);
}
/**
* librdf_new_storage_from_storage - Copy constructor - create a new librdf_storage object from an existing one
* @old_storage: the existing storage #librdf_storage to use
*
* Should create a new storage in the same context as the existing one
* as appropriate for the storage. For example, in a RDBMS storage
* it would be a new database, or in on disk it would be a new
* set of files. This will mean automatically generating
* a new identifier for the storage, maybe based on the existing
* storage identifier.
*
* Return value: a new #librdf_storage object or NULL on failure
*
*/
librdf_storage*
librdf_new_storage_from_storage(librdf_storage* old_storage)
{
librdf_storage* new_storage;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(old_storage, librdf_storage, NULL);
if(!old_storage->factory->clone) {
librdf_log(old_storage->world,
0, LIBRDF_LOG_ERROR, LIBRDF_FROM_STORAGE, NULL,
"clone method not implemented for storage factory %s",
old_storage->factory->name);
return NULL;
}
new_storage=(librdf_storage*)LIBRDF_CALLOC(librdf_storage, 1,
sizeof(librdf_storage));
if(!new_storage)
return NULL;
new_storage->context=(char*)LIBRDF_CALLOC(librdf_storage_context, 1,
old_storage->factory->context_length);
if(!new_storage->context) {
librdf_free_storage(new_storage);
return NULL;
}
new_storage->world=old_storage->world;
/* do this now so librdf_free_storage won't call new factory on
* partially copied storage
*/
new_storage->factory=old_storage->factory;
/* clone is assumed to do leave the new storage in the same state
* after an init() method on an existing storage - i.e ready to
* use but closed.
*/
if(old_storage->factory->clone(new_storage, old_storage)) {
librdf_free_storage(new_storage);
return NULL;
}
new_storage->usage=1;
return new_storage;
}
/**
* librdf_new_storage_from_factory:
* @world: redland world object
* @factory: the factory to use to construct the storage
* @name: name to use for storage
* @options: #librdf_hash of options to initialise storage
*
* Constructor - create a new #librdf_storage object.
*
* If the options are present, they become owned by the storage
* and should no longer be used.
*
* Return value: a new #librdf_storage object or NULL on failure
*
*/
librdf_storage*
librdf_new_storage_from_factory (librdf_world *world,
librdf_storage_factory* factory,
const char *name,
librdf_hash* options) {
librdf_storage* storage;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(factory, librdf_storage_factory, NULL);
if(!factory) {
librdf_free_hash(options);
return NULL;
}
storage=(librdf_storage*)LIBRDF_CALLOC(librdf_storage, 1,
sizeof(librdf_storage));
if(!storage) {
librdf_free_hash(options);
return NULL;
}
storage->world=world;
storage->context=(char*)LIBRDF_CALLOC(librdf_storage_context, 1,
factory->context_length);
if(!storage->context) {
librdf_free_hash(options);
librdf_free_storage(storage);
return NULL;
}
storage->factory=factory;
if(factory->init(storage, name, options)) {
librdf_free_storage(storage);
return NULL;
}
storage->usage=1;
return storage;
}
/**
* librdf_free_storage:
* @storage: #librdf_storage object
*
* Destructor - destroy a #librdf_storage object.
**/
void
librdf_free_storage (librdf_storage* storage)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN(storage, librdf_storage);
if(--storage->usage)
return;
if(storage->factory)
storage->factory->terminate(storage);
if(storage->context)
LIBRDF_FREE(librdf_storage_context, storage->context);
LIBRDF_FREE(librdf_storage, storage);
}
void
librdf_storage_add_reference(librdf_storage *storage)
{
storage->usage++;
}
void
librdf_storage_remove_reference(librdf_storage *storage)
{
storage->usage--;
}
/* methods */
/**
* librdf_storage_open:
* @storage: #librdf_storage object
* @model: model stored
*
* Start a model / storage association.
*
* This is ended with librdf_storage_close()
*
* Return value: non 0 on failure
**/
int
librdf_storage_open(librdf_storage* storage, librdf_model* model)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
return storage->factory->open(storage, model);
}
/**
* librdf_storage_close:
* @storage: #librdf_storage object
*
* End a model / storage association.
*
* Return value: non 0 on failure
**/
int
librdf_storage_close(librdf_storage* storage)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
return storage->factory->close(storage);
}
/**
* librdf_storage_size:
* @storage: #librdf_storage object
*
* Get the number of statements stored.
*
* Return value: The number of statements or < 0 if cannot be determined
**/
int
librdf_storage_size(librdf_storage* storage)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, -1);
return storage->factory->size(storage);
}
/**
* librdf_storage_add_statement:
* @storage: #librdf_storage object
* @statement: #librdf_statement statement to add
*
* Add a statement to a storage.
*
* The passed-in statement is copied when added to the store, not
* shared with the store.
*
* If the statement already exists in the store, it is not added
* unless Redland contexts are being used.
*
* Enforces that the statement is legal for RDF - URI or blank subject,
* URI predicate and URI or blank or literal object (i.e. anything).
*
* Return value: non 0 on failure, <0 on error, >0 if statement was illegal
**/
int
librdf_storage_add_statement(librdf_storage* storage,
librdf_statement* statement)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 1);
/* subject can be a URI or blank node */
if(!librdf_node_is_resource(statement->subject) &&
!librdf_node_is_blank(statement->subject))
return 1;
/* subject can only be a URI */
if(!librdf_node_is_resource(statement->predicate))
return 1;
/* object can be any node - no check needed */
if(storage->factory->add_statement)
return storage->factory->add_statement(storage, statement);
return -1;
}
/**
* librdf_storage_add_statements:
* @storage: #librdf_storage object
* @statement_stream: #librdf_stream of statements
*
* Add a stream of statements to the storage.
*
* If any of the statements already exists in the store, they are not
* added unless Redland contexts are being used.
*
* Return value: non 0 on failure
**/
int
librdf_storage_add_statements(librdf_storage* storage,
librdf_stream* statement_stream)
{
int status=0;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement_stream, librdf_stream, 1);
if(storage->factory->add_statements)
return storage->factory->add_statements(storage, statement_stream);
while(!librdf_stream_end(statement_stream)) {
librdf_statement* statement=librdf_stream_get_object(statement_stream);
if(statement) {
status=librdf_storage_add_statement(storage, statement);
if(status > 0)
/* just skip illegal statements */
status=0;
}
else
status=1;
if(status)
break;
librdf_stream_next(statement_stream);
}
return status;
}
/**
* librdf_storage_remove_statement:
* @storage: #librdf_storage object
* @statement: #librdf_statement statement to remove
*
* Remove a statement from the storage.
*
* Return value: non 0 on failure
**/
int
librdf_storage_remove_statement(librdf_storage* storage,
librdf_statement* statement)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 1);
if(storage->factory->remove_statement)
return storage->factory->remove_statement(storage, statement);
return 1;
}
/**
* librdf_storage_contains_statement:
* @storage: #librdf_storage object
* @statement: #librdf_statement statement to check
*
* Test if a given statement is present in the storage.
*
* Return value: non 0 if the storage contains the statement (>0 if illegal statement)
**/
int
librdf_storage_contains_statement(librdf_storage* storage,
librdf_statement* statement)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 1);
/* subject can be a URI or blank node */
if(!statement->subject ||
(!librdf_node_is_resource(statement->subject) &&
!librdf_node_is_blank(statement->subject)))
return 1;
/* subject can only be a URI */
if(!statement->predicate || !librdf_node_is_resource(statement->predicate))
return 1;
if(!statement->object)
return 1;
return storage->factory->contains_statement(storage, statement);
}
/**
* librdf_storage_serialise:
* @storage: #librdf_storage object
*
* Serialise the storage as a librdf_stream of statemetns.
*
* Return value: #librdf_stream of statements or NULL on failure
**/
librdf_stream*
librdf_storage_serialise(librdf_storage* storage)
{
return storage->factory->serialise(storage);
}
/**
* librdf_storage_find_statements:
* @storage: #librdf_storage object
* @statement: #librdf_statement partial statement to find
*
* Search the storage for matching statements.
*
* Searches the storage for a (partial) statement as described in
* librdf_statement_match() and returns a #librdf_stream of
* matching #librdf_statement objects.
*
* Return value: #librdf_stream of matching statements (may be empty) or NULL on failure
**/
librdf_stream*
librdf_storage_find_statements(librdf_storage* storage,
librdf_statement* statement)
{
librdf_node *subject, *predicate, *object;
librdf_iterator *iterator;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, NULL);
subject=librdf_statement_get_subject(statement);
predicate=librdf_statement_get_predicate(statement);
object=librdf_statement_get_object(statement);
/* try to pick the most efficient storage back end */
/* only subject/source field blank -> use find_sources */
if(!subject && predicate && object &&
storage->factory->find_sources) {
iterator=storage->factory->find_sources(storage, predicate, object);
if(iterator)
return librdf_new_stream_from_node_iterator(iterator, statement,
LIBRDF_STATEMENT_SUBJECT);
return NULL;
}
/* only predicate/arc field blank -> use find_arcs */
if(subject && !predicate && object &&
storage->factory->find_arcs) {
iterator=storage->factory->find_arcs(storage, subject, object);
if(iterator)
return librdf_new_stream_from_node_iterator(iterator, statement,
LIBRDF_STATEMENT_PREDICATE);
return NULL;
}
/* only object/target field blank -> use find_targets */
if(subject && predicate && !object &&
storage->factory->find_targets) {
iterator=storage->factory->find_targets(storage, subject, predicate);
if(iterator)
return librdf_new_stream_from_node_iterator(iterator, statement,
LIBRDF_STATEMENT_OBJECT);
return NULL;
}
return storage->factory->find_statements(storage, statement);
}
typedef struct {
librdf_storage *storage;
librdf_stream *stream;
librdf_statement *partial_statement;
librdf_statement_part want;
librdf_node *object_node;
librdf_node *context_node;
} librdf_storage_stream_to_node_iterator_context;
static int
librdf_storage_stream_to_node_iterator_is_end(void* iterator)
{
librdf_storage_stream_to_node_iterator_context* context=(librdf_storage_stream_to_node_iterator_context*)iterator;
return librdf_stream_end(context->stream);
}
static int
librdf_storage_stream_to_node_iterator_next_method(void* iterator)
{
librdf_storage_stream_to_node_iterator_context* context=(librdf_storage_stream_to_node_iterator_context*)iterator;
if(context->object_node) {
librdf_free_node(context->object_node);
context->object_node=NULL;
}
if(context->context_node) {
librdf_free_node(context->context_node);
context->context_node=NULL;
}
return librdf_stream_next(context->stream);
}
static void*
librdf_storage_stream_to_node_iterator_get_method(void* iterator, int flags)
{
librdf_storage_stream_to_node_iterator_context* context=(librdf_storage_stream_to_node_iterator_context*)iterator;
librdf_node* node;
librdf_statement* statement=librdf_stream_get_object(context->stream);
if(!statement)
return NULL;
switch(flags) {
case LIBRDF_ITERATOR_GET_METHOD_GET_OBJECT:
if(!context->object_node) {
switch(context->want) {
case LIBRDF_STATEMENT_SUBJECT: /* SOURCES (subjects) */
node=librdf_statement_get_subject(statement);
break;
case LIBRDF_STATEMENT_PREDICATE: /* ARCS (predicates) */
node=librdf_statement_get_predicate(statement);
break;
case LIBRDF_STATEMENT_OBJECT: /* TARGETS (objects) */
node=librdf_statement_get_object(statement);
break;
case LIBRDF_STATEMENT_ALL:
default: /* error */
librdf_log(statement->world,
0, LIBRDF_LOG_ERROR, LIBRDF_FROM_STORAGE, NULL,
"Unknown statement part %d", context->want);
node=NULL;
}
context->object_node=librdf_new_node_from_node(node);
}
node=context->object_node;
break;
case LIBRDF_ITERATOR_GET_METHOD_GET_CONTEXT:
if(!context->context_node) {
node=(librdf_node*)librdf_stream_get_context(context->stream);
context->context_node=librdf_new_node_from_node(node);
}
node=context->context_node;
break;
default:
librdf_log(statement->world,
0, LIBRDF_LOG_ERROR, LIBRDF_FROM_STORAGE, NULL,
"Unknown iterator method flag %d", flags);
node=NULL;
}
return (void*)node;
}
static void
librdf_storage_stream_to_node_iterator_finished(void* iterator)
{
librdf_storage_stream_to_node_iterator_context* context=(librdf_storage_stream_to_node_iterator_context*)iterator;
librdf_statement *partial_statement=context->partial_statement;
if(partial_statement)
librdf_free_statement(partial_statement);
if(context->stream)
librdf_free_stream(context->stream);
if(context->storage)
librdf_storage_remove_reference(context->storage);
if(context->object_node)
librdf_free_node(context->object_node);
if(context->context_node)
librdf_free_node(context->context_node);
LIBRDF_FREE(librdf_storage_stream_to_node_iterator_context, context);
}
/*
* librdf_storage_node_stream_to_node_create - Create a stream for get sources, targets or arcs methods using find_statements method
* @storage: the storage object to use
* @node1: the first node to encode in the key (or NULL if not needed)
* @node2: the second node to encode in the key (or NULL if not needed)
* @want: the field required from the statement
*
* node1 and node2 cannot both be NULL
*
* Return value: a new #librdf_iterator or NULL on failure
**/
static librdf_iterator*
librdf_storage_node_stream_to_node_create(librdf_storage* storage,
librdf_node *node1,
librdf_node *node2,
librdf_statement_part want)
{
librdf_statement *partial_statement;
librdf_stream *stream;
librdf_storage_stream_to_node_iterator_context* context;
librdf_iterator *iterator;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
LIBRDF_ASSERT_RETURN(node1 == NULL && node2 == NULL, "both node objects are NULL", NULL);
partial_statement=librdf_new_statement(storage->world);
if(!partial_statement)
return NULL;
context=(librdf_storage_stream_to_node_iterator_context*)LIBRDF_CALLOC(librdf_storage_stream_to_node_iterator_context, 1, sizeof(librdf_storage_stream_to_node_iterator_context));
if(!context) {
librdf_free_statement(partial_statement);
return NULL;
}
node1=librdf_new_node_from_node(node1);
node2=librdf_new_node_from_node(node2);
switch(want) {
case LIBRDF_STATEMENT_SUBJECT:
librdf_statement_set_predicate(partial_statement, node1);
librdf_statement_set_object(partial_statement, node2);
break;
case LIBRDF_STATEMENT_PREDICATE:
librdf_statement_set_subject(partial_statement, node1);
librdf_statement_set_object(partial_statement, node2);
break;
case LIBRDF_STATEMENT_OBJECT:
librdf_statement_set_subject(partial_statement, node1);
librdf_statement_set_predicate(partial_statement, node2);
break;
case LIBRDF_STATEMENT_ALL:
default:
librdf_free_node(node1);
librdf_free_node(node2);
librdf_free_statement(partial_statement);
librdf_log(storage->world,
0, LIBRDF_LOG_ERROR, LIBRDF_FROM_STORAGE, NULL,
"Illegal statement part %d seen", want);
return NULL;
}
stream=storage->factory->find_statements(storage, partial_statement);
if(!stream) {
librdf_storage_stream_to_node_iterator_finished(context);
return librdf_new_empty_iterator(storage->world);
}
/* initialise context */
context->partial_statement=partial_statement;
context->stream=stream;
context->want=want;
context->storage=storage;
librdf_storage_add_reference(context->storage);
iterator=librdf_new_iterator(storage->world,
(void*)context,
librdf_storage_stream_to_node_iterator_is_end,
librdf_storage_stream_to_node_iterator_next_method,
librdf_storage_stream_to_node_iterator_get_method,
librdf_storage_stream_to_node_iterator_finished);
if(!iterator)
librdf_storage_stream_to_node_iterator_finished(context);
return iterator;
}
/**
* librdf_storage_get_sources:
* @storage: #librdf_storage object
* @arc: #librdf_node arc
* @target: #librdf_node target
*
* Return the sources (subjects) of arc in an RDF graph given arc (predicate) and target (object).
*
* Searches the storage for arcs matching the given arc and target
* and returns a list of the source #librdf_node objects as an iterator
*
* Return value: #librdf_iterator of #librdf_node objects (may be empty) or NULL on failure
**/
librdf_iterator*
librdf_storage_get_sources(librdf_storage *storage,
librdf_node *arc, librdf_node *target)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(arc, librdf_node, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(target, librdf_node, NULL);
if (storage->factory->find_sources)
return storage->factory->find_sources(storage, arc, target);
return librdf_storage_node_stream_to_node_create(storage, arc, target,
LIBRDF_STATEMENT_SUBJECT);
}
/**
* librdf_storage_get_arcs:
* @storage: #librdf_storage object
* @source: #librdf_node source
* @target: #librdf_node target
*
* Return the arcs (predicates) of an arc in an RDF graph given source (subject) and target (object).
*
* Searches the storage for arcs matching the given source and target
* and returns a list of the arc #librdf_node objects as an iterator
*
* Return value: #librdf_iterator of #librdf_node objects (may be empty) or NULL on failure
**/
librdf_iterator*
librdf_storage_get_arcs(librdf_storage *storage,
librdf_node *source, librdf_node *target)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(source, librdf_node, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(target, librdf_node, NULL);
if (storage->factory->find_arcs)
return storage->factory->find_arcs(storage, source, target);
return librdf_storage_node_stream_to_node_create(storage, source, target,
LIBRDF_STATEMENT_PREDICATE);
}
/**
* librdf_storage_get_targets:
* @storage: #librdf_storage object
* @source: #librdf_node source
* @arc: #librdf_node arc
*
* Return the targets (objects) of an arc in an RDF graph given source (subject) and arc (predicate).
*
* Searches the storage for targets matching the given source and arc
* and returns a list of the source #librdf_node objects as an iterator
*
* Return value: #librdf_iterator of #librdf_node objects (may be empty) or NULL on failure
**/
librdf_iterator*
librdf_storage_get_targets(librdf_storage *storage,
librdf_node *source, librdf_node *arc)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(source, librdf_node, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(arc, librdf_node, NULL);
if (storage->factory->find_targets)
return storage->factory->find_targets(storage, source, arc);
return librdf_storage_node_stream_to_node_create(storage, source, arc,
LIBRDF_STATEMENT_OBJECT);
}
/**
* librdf_storage_get_arcs_in:
* @storage: #librdf_storage object
* @node: #librdf_node resource node
*
* Return the properties pointing to the given resource.
*
* Return value: #librdf_iterator of #librdf_node objects (may be empty) or NULL on failure
**/
librdf_iterator*
librdf_storage_get_arcs_in(librdf_storage *storage, librdf_node *node)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(node, librdf_node, NULL);
if (storage->factory->get_arcs_in)
return storage->factory->get_arcs_in(storage, node);
return librdf_storage_node_stream_to_node_create(storage, NULL, node,
LIBRDF_STATEMENT_PREDICATE);
}
/**
* librdf_storage_get_arcs_out:
* @storage: #librdf_storage object
* @node: #librdf_node resource node
*
* Return the properties pointing from the given resource.
*
* Return value: #librdf_iterator of #librdf_node objects (may be empty) or NULL on failure
**/
librdf_iterator*
librdf_storage_get_arcs_out(librdf_storage *storage, librdf_node *node)
{
if (storage->factory->get_arcs_out)
return storage->factory->get_arcs_out(storage, node);
return librdf_storage_node_stream_to_node_create(storage, node, NULL,
LIBRDF_STATEMENT_PREDICATE);
}
/**
* librdf_storage_has_arc_in:
* @storage: #librdf_storage object
* @node: #librdf_node resource node
* @property: #librdf_node property node
*
* Check if a node has a given property pointing to it.
*
* Return value: non 0 if arc property does point to the resource node
**/
int
librdf_storage_has_arc_in(librdf_storage *storage, librdf_node *node,
librdf_node *property)
{
librdf_iterator *iterator;
int status;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 0);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(node, librdf_node, 0);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(property, librdf_node, 0);
if (storage->factory->has_arc_in)
return storage->factory->has_arc_in(storage, node, property);
iterator=librdf_storage_get_sources(storage, property, node);
if(!iterator)
return 0;
/* a non-empty list of sources is success */
status=!librdf_iterator_end(iterator);
librdf_free_iterator(iterator);
return status;
}
/**
* librdf_storage_has_arc_out:
* @storage: #librdf_storage object
* @node: #librdf_node resource node
* @property: #librdf_node property node
*
* Check if a node has a given property pointing from it.
*
* Return value: non 0 if arc property does point from the resource node
**/
int
librdf_storage_has_arc_out(librdf_storage *storage, librdf_node *node,
librdf_node *property)
{
librdf_iterator *iterator;
int status;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 0);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(node, librdf_node, 0);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(property, librdf_node, 0);
if (storage->factory->has_arc_out)
return storage->factory->has_arc_out(storage, node, property);
iterator=librdf_storage_get_targets(storage, node, property);
if(!iterator)
return 0;
/* a non-empty list of targets is success */
status=!librdf_iterator_end(iterator);
librdf_free_iterator(iterator);
return status;
}
/**
* librdf_storage_context_add_statement:
* @storage: #librdf_storage object
* @context: #librdf_node context node
* @statement: #librdf_statement statement to add
*
* Add a statement to a storage in a context.
*
* If @context is NULL, this is equivalent to librdf_storage_add_statement
*
* Return value: non 0 on failure
**/
int
librdf_storage_context_add_statement(librdf_storage* storage,
librdf_node* context,
librdf_statement* statement)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 1);
if(!context)
return librdf_storage_add_statement(storage, statement);
if(storage->factory->context_add_statement)
return storage->factory->context_add_statement(storage, context, statement);
return 1;
}
/**
* librdf_storage_context_add_statements:
* @storage: #librdf_storage object
* @context: #librdf_node context
* @stream: #librdf_stream stream object
*
* Add statements to a storage with a context.
*
* If @context is NULL, this is equivalent to librdf_storage_add_statements
*
* Return value: Non 0 on failure
**/
int
librdf_storage_context_add_statements(librdf_storage* storage,
librdf_node* context,
librdf_stream* stream)
{
int status=0;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(stream, librdf_stream, 1);
if(!context)
return librdf_storage_add_statements(storage, stream);
if(storage->factory->context_add_statements)
return storage->factory->context_add_statements(storage, context, stream);
if(!storage->factory->context_add_statement)
return 1;
if(!stream)
return 1;
while(!librdf_stream_end(stream)) {
librdf_statement* statement=librdf_stream_get_object(stream);
if(!statement)
break;
status=librdf_storage_context_add_statement(storage, context, statement);
if(status)
break;
librdf_stream_next(stream);
}
return status;
}
/**
* librdf_storage_context_remove_statement:
* @storage: #librdf_storage object
* @context: #librdf_node context node
* @statement: #librdf_statement statement to remove
*
* Remove a statement from a storage in a context.
*
* If @context is NULL, this is equivalent to librdf_storage_remove_statement
*
* Return value: non 0 on failure
**/
int
librdf_storage_context_remove_statement(librdf_storage* storage,
librdf_node* context,
librdf_statement* statement)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(context, librdf_statement, 1);
if(!storage->factory->context_remove_statement)
return 1;
return storage->factory->context_remove_statement(storage, context, statement);
}
/**
* librdf_storage_context_remove_statements:
* @storage: #librdf_storage object
* @context: #librdf_uri context
*
* Remove statements from a storage with the given context.
*
* Return value: Non 0 on failure
**/
int
librdf_storage_context_remove_statements(librdf_storage* storage,
librdf_node* context)
{
librdf_stream *stream;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
if(storage->factory->context_remove_statements)
return storage->factory->context_remove_statements(storage, context);
if(!storage->factory->context_remove_statement)
return 1;
stream=librdf_storage_context_as_stream(storage, context);
if(!stream)
return 1;
while(!librdf_stream_end(stream)) {
librdf_statement *statement=librdf_stream_get_object(stream);
if(!statement)
break;
librdf_storage_context_remove_statement(storage, context, statement);
librdf_stream_next(stream);
}
librdf_free_stream(stream);
return 0;
}
/**
* librdf_storage_context_as_stream:
* @storage: #librdf_storage object
* @context: #librdf_node context node
*
* List all statements in a storage context.
*
* Return value: #librdf_stream of statements or NULL on failure or context is empty
**/
librdf_stream*
librdf_storage_context_as_stream(librdf_storage* storage, librdf_node* context)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
return storage->factory->context_serialise(storage, context);
}
/**
* librdf_storage_context_serialise:
* @storage: #librdf_storage object
* @context: #librdf_node context node
*
* List all statements in a storage context (DEPRECATED).
*
* DEPRECATED to reduce confusion with the librdf_serializer class.
* Please use librdf_storage_context_as_stream.
*
* Return value: #librdf_stream of statements or NULL on failure or context is empty
**/
librdf_stream*
librdf_storage_context_serialise(librdf_storage* storage,
librdf_node* context)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
return librdf_storage_context_as_stream(storage, context);
}
/**
* librdf_storage_supports_query:
* @storage: #librdf_storage object
* @query: #librdf_query query object
*
* Check if a storage system supports a query language.
*
* Not implemented.
*
* Return value: non-0 if the query is supported.
**/
int
librdf_storage_supports_query(librdf_storage* storage, librdf_query *query)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 0);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(query, librdf_query, 0);
return 0;
}
/**
* librdf_storage_query_execute:
* @storage: #librdf_storage object
* @query: #librdf_query query object
*
* Run the given query against the storage.
*
* Not implemented.
*
* Return value: #librdf_query_results or NULL on failure
**/
librdf_query_results*
librdf_storage_query_execute(librdf_storage* storage, librdf_query *query)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(query, librdf_query, NULL);
return NULL;
}
/**
* librdf_storage_sync:
* @storage: #librdf_storage object
*
* Synchronise the storage to the storage implementation.
*
* Return value: non-0 on failure
**/
int
librdf_storage_sync(librdf_storage* storage)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, 1);
if(storage->factory->sync)
return storage->factory->sync(storage);
return 0;
}
/**
* librdf_storage_find_statements_in_context:
* @storage: #librdf_storage object
* @statement: #librdf_statement partial statement to find
* @context_node: context #librdf_node (or NULL)
*
* Search the storage for matching statements in a given context.
*
* Searches the storage for a (partial) statement as described in
* librdf_statement_match() in the given context and returns a
* #librdf_stream of matching #librdf_statement objects. If
* context is NULL, this is equivalent to librdf_storage_find_statements.
*
* Return value: #librdf_stream of matching statements (may be empty) or NULL on failure
**/
librdf_stream*
librdf_storage_find_statements_in_context(librdf_storage* storage, librdf_statement* statement, librdf_node* context_node)
{
librdf_stream *stream;
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, NULL);
if(storage->factory->find_statements_in_context)
return storage->factory->find_statements_in_context(storage, statement, context_node);
statement=librdf_new_statement_from_statement(statement);
if(!statement)
return NULL;
stream=librdf_storage_context_as_stream(storage, context_node);
if(!stream) {
librdf_free_statement(statement);
return NULL;
}
librdf_stream_add_map(stream,
&librdf_stream_statement_find_map,
(librdf_stream_map_free_context_handler)&librdf_free_statement, (void*)statement);
return stream;
}
/**
* librdf_storage_get_contexts:
* @storage: #librdf_storage object
*
* Return the list of contexts in the store.
*
* Returns an iterator of #librdf_node context nodes for each
* context in the store.
*
* Return value: #librdf_iterator of context nodes or NULL on failure or if contexts are not supported
**/
librdf_iterator*
librdf_storage_get_contexts(librdf_storage* storage)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
if(storage->factory->get_contexts)
return storage->factory->get_contexts(storage);
else
return NULL;
}
/**
* librdf_storage_get_feature:
* @storage: #librdf_storage object
* @feature: #librdf_uri feature property
*
* Get the value of a storage feature.
*
* Return value: new #librdf_node feature value or NULL if no such feature
* exists or the value is empty.
**/
librdf_node*
librdf_storage_get_feature(librdf_storage* storage, librdf_uri* feature)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, NULL);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(feature, librdf_uri, NULL);
if(storage->factory->get_feature)
return storage->factory->get_feature(storage, feature);
return NULL;
}
/**
* librdf_storage_set_feature:
* @storage: #librdf_storage object
* @feature: #librdf_uri feature property
* @value: #librdf_node feature property value
*
* Set the value of a storage feature.
*
* Return value: non 0 on failure (negative if no such feature)
**/
int
librdf_storage_set_feature(librdf_storage* storage, librdf_uri* feature,
librdf_node* value)
{
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(storage, librdf_storage, -1);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(feature, librdf_uri, -1);
LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(value, librdf_node, -1);
if(storage->factory->set_feature)
return storage->factory->set_feature(storage, feature, value);
return -1;
}
/**
* librdf_storage_find_statements_with_options:
* @storage: #librdf_storage object
* @statement: #librdf_statement partial statement to find
* @context_node: #librdf_node context node or NULL.
* @options: #librdf_hash of matching options or NULL
*
* Search the storage for matching statements with match options.
*
* Searches the storage for a (partial) statement as described in
* librdf_statement_match() and returns a #librdf_stream of
* matching #librdf_statement objects.
*
* If options is given then the match is made according to
* the given options. If options is NULL, this is equivalent
* to librdf_storage_find_statements_in_context.
*
* Return value: #librdf_stream of matching statements (may be empty) or NULL on failure
**/
librdf_stream*
librdf_storage_find_statements_with_options(librdf_storage* storage,
librdf_statement* statement,
librdf_node* context_node,
librdf_hash* options)
{
if(storage->factory->find_statements_with_options)
return storage->factory->find_statements_with_options(storage, statement, context_node, options);
else
return librdf_storage_find_statements_in_context(storage, statement, context_node);
}
#endif
/* TEST CODE */
#ifdef STANDALONE
/* one more prototype */
int main(int argc, char *argv[]);
int
main(int argc, char *argv[])
{
librdf_storage* storage;
const char *program=librdf_basename((const char*)argv[0]);
librdf_world *world;
world=librdf_new_world();
/* initialise hash, model and storage modules */
librdf_init_hash(world);
librdf_init_storage(world);
librdf_init_model(world);
fprintf(stdout, "%s: Creating storage\n", program);
storage=librdf_new_storage(world, NULL, "test", NULL);
if(!storage) {
fprintf(stderr, "%s: Failed to create new storage\n", program);
return(1);
}
fprintf(stdout, "%s: Opening storage\n", program);
if(librdf_storage_open(storage, NULL)) {
fprintf(stderr, "%s: Failed to open storage\n", program);
return(1);
}
/* Can do nothing here since need model and storage working */
fprintf(stdout, "%s: Closing storage\n", program);
librdf_storage_close(storage);
fprintf(stdout, "%s: Freeing storage\n", program);
librdf_free_storage(storage);
/* finish model and storage modules */
librdf_finish_model(world);
librdf_finish_storage(world);
librdf_finish_hash(world);
LIBRDF_FREE(librdf_world, world);
/* keep gcc -Wall happy */
return(0);
}
#endif