Make serd.h C++ safe.

Add C++ API (serdmm.hpp).
Add serialisation API (easily write models to files).


git-svn-id: http://svn.drobilla.net/sord/trunk@36 3d64ff67-21c5-427c-a301-fe4f08042e5a

1 files changed, 504 insertions, 0 deletions

diff --git a/sord/sordmm.hpp b/sord/sordmm.hpp
new file mode 100644
index 0000000..4661458
--- /dev/null
+++ b/sord/sordmm.hpp
@@ -0,0 +1,504 @@
+/* Sord, a lightweight RDF model library.
+ * Copyright 2010-2011 David Robillard <d@drobilla.net>
+ *
+ * Sord is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Sord is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ * License for details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file sordmm.hpp
+ * Public Sord C++ API.
+ */
+
+#ifndef SORD_SORDMM_HPP
+#define SORD_SORDMM_HPP
+
+#include <cassert>
+#include <cstring>
+#include <iostream>
+#include <set>
+#include <string>
+
+#include <boost/utility.hpp>
+#include <glibmm/ustring.h>
+
+#include "serd/serd.h"
+#include "sord/sord.h"
+
+#define SORD_NS_XSD "http://www.w3.org/2001/XMLSchema#"
+
+namespace Sord {
+
+/** C++ wrapper for a Sord object. */
+template <typename T>
+class Wrapper {
+public:
+	inline Wrapper(T c_obj = NULL) : _c_obj(c_obj) {}
+
+	inline T       c_obj()       { return _c_obj; }
+	inline const T c_obj() const { return _c_obj; }
+
+protected:
+	T _c_obj;
+};
+
+/** Collection of RDF namespaces with prefixes. */
+class Namespaces : public Wrapper<SerdEnv> {
+public:
+	Namespaces() : Wrapper<SerdEnv>(serd_env_new()) {}
+
+	static inline SerdNode string_to_node(SerdType type, const std::string& s) {
+		SerdNode ret = {
+			type, s.length() + 1, s.length(), (const uint8_t*)s.c_str() };
+		return ret;
+	}
+
+	inline void add(const std::string& name,
+	                const std::string& uri) {
+		const SerdNode name_node = string_to_node(SERD_LITERAL, name);
+		const SerdNode uri_node  = string_to_node(SERD_URI,     uri);
+		serd_env_add(_c_obj, &name_node, &uri_node);
+	}
+
+	inline std::string qualify(std::string uri) const {
+		const SerdNode uri_node = string_to_node(SERD_URI, uri);
+		SerdNode       prefix;
+		SerdChunk      suffix;
+		if (serd_env_qualify(_c_obj, &uri_node, &prefix, &suffix)) {
+			std::string ret((const char*)prefix.buf, prefix.n_bytes - 1);
+			ret.append((const char*)suffix.buf, suffix.len);
+			return ret;
+		}
+		return uri;
+	}
+
+	inline std::string expand(const std::string& curie) const {
+		assert(curie.find(":") != std::string::npos);
+		SerdNode  curie_node = string_to_node(SERD_CURIE, curie);
+		SerdChunk uri_prefix;
+		SerdChunk uri_suffix;
+		if (serd_env_expand(_c_obj, &curie_node, &uri_prefix, &uri_suffix)) {
+			std::string ret((const char*)uri_prefix.buf, uri_prefix.len);
+			ret.append((const char*)uri_suffix.buf, uri_suffix.len);
+			return ret;
+		}
+		std::cerr << "CURIE `" << curie << "' has unknown prefix." << std::endl;
+		return curie;
+	}
+};
+
+/** Sord library state. */
+class World : public boost::noncopyable, public Wrapper<SordWorld> {
+public:
+	inline World()
+		: _next_blank_id(0)
+	{
+		_c_obj = sord_world_new();
+		add_prefix("rdf", "http://www.w3.org/1999/02/22-rdf-syntax-ns#");
+	}
+
+	inline ~World() {
+		sord_world_free(_c_obj);
+	}
+	
+	inline uint64_t blank_id() { return _next_blank_id++; }
+
+	inline void add_prefix(const std::string& prefix, const std::string& uri) {
+		_prefixes.add(prefix, uri);
+	}
+
+	inline const Namespaces& prefixes() const { return _prefixes; }
+	inline SordWorld         world()          { return _c_obj; }
+
+private:
+	Namespaces            _prefixes;
+	std::set<std::string> _blank_ids;
+	uint64_t              _next_blank_id;
+};
+
+/** An RDF Node (resource, literal, etc)
+ */
+class Node : public Wrapper<SordNode> {
+public:
+	enum Type {
+		UNKNOWN  = 0,
+		RESOURCE = SORD_URI,
+		BLANK    = SORD_BLANK,
+		LITERAL  = SORD_LITERAL
+	};
+
+	inline Node() : Wrapper<SordNode>(NULL), _world(NULL) {}
+
+	inline Node(World& world, Type t, const std::string& s);
+	inline Node(World& world);
+	inline Node(World& world, SordNode node);
+	inline Node(const Node& other);
+	inline ~Node();
+
+	inline Type type() const {
+		return _c_obj ? (Type)sord_node_get_type(_c_obj) : UNKNOWN;
+	}
+
+	inline SordNode get_node() const { return _c_obj; }
+
+	inline bool is_valid() const { return type() != UNKNOWN; }
+
+	inline bool operator<(const Node& other) const {
+		if (type() != other.type()) {
+			return type() < other.type();
+		} else {
+			return to_string() < other.to_string();
+		}
+	}
+
+	const Node& operator=(const Node& other) {
+		if (_c_obj)
+			sord_node_free(_c_obj);
+		_world = other._world;
+		_c_obj = other._c_obj ? sord_node_copy(other._c_obj) : NULL;
+		return *this;
+	}
+
+	inline bool operator==(const Node& other) const {
+		return sord_node_equals(_c_obj, other._c_obj);
+	}
+
+	inline const uint8_t* to_u_string() const;
+	inline const char*    to_c_string() const;
+	inline std::string    to_string() const;
+
+	inline bool is_literal_type(const char* type_uri) const;
+
+	inline bool is_resource() const { return _c_obj && type() == RESOURCE; }
+	inline bool is_blank()    const { return _c_obj && type() == BLANK; }
+	inline bool is_int()      const { return is_literal_type(SORD_NS_XSD "integer"); }
+	inline bool is_float()    const { return is_literal_type(SORD_NS_XSD "decimal"); }
+	inline bool is_bool()     const { return is_literal_type(SORD_NS_XSD "boolean"); }
+
+	inline int   to_int()   const;
+	inline float to_float() const;
+	inline bool  to_bool()  const;
+
+	inline static Node blank_id(World& world, const std::string base="b") {
+		const uint64_t num = world.blank_id();
+		std::ostringstream ss;
+		ss << base << num;
+		return Node(world, Node::BLANK, ss.str());
+	}
+
+private:
+	World* _world;
+};
+
+inline std::ostream&
+operator<<(std::ostream& os, const Node& node)
+{
+	return os << node.to_string() << std::endl;
+}
+
+class Resource : public Node {
+public:
+	inline Resource(World& world, const std::string& s) : Node(world, Node::RESOURCE, s) {}
+};
+
+class Curie : public Node {
+public:
+	inline Curie(World& world, const std::string& s)
+		: Node(world, Node::RESOURCE, world.prefixes().expand(s)) {}
+};
+
+class Literal : public Node {
+public:
+	inline Literal(World& world, const std::string& s) : Node(world, Node::LITERAL, s) {}
+};
+
+inline
+Node::Node(World& world, Type type, const std::string& s)
+	: _world(&world)
+{
+	switch (type) {
+	case RESOURCE:
+		assert(s.find(":") == std::string::npos
+		       || s.substr(0, 5) == "http:"
+		       || s.substr(0, 5) == "file:"
+		       || s.substr(0, 4) == "urn:");
+		_c_obj = sord_new_uri(
+			world.world(), (const unsigned char*)s.c_str());
+		break;
+	case LITERAL:
+		_c_obj = sord_new_literal(
+			world.world(), NULL, (const unsigned char*)s.c_str(), NULL);
+		break;
+	case BLANK:
+		_c_obj = sord_new_blank(
+			world.world(), (const unsigned char*)s.c_str());
+		break;
+	default:
+		_c_obj = NULL;
+	}
+
+	assert(this->type() == type);
+}
+
+inline
+Node::Node(World& world)
+	: _world(&world)
+{
+	Node me = blank_id(world);
+	*this = me;
+}
+
+inline
+Node::Node(World& world, SordNode node)
+	: _world(&world)
+{
+	_c_obj = node ? sord_node_copy(node) : NULL;
+}
+
+inline
+Node::Node(const Node& other)
+	: Wrapper<SordNode>()
+	, _world(other._world)
+{
+	if (_world) {
+		_c_obj = other._c_obj ? sord_node_copy(other._c_obj) : NULL;
+	}
+
+	assert((!_c_obj && !other._c_obj) || to_string() == other.to_string());
+}
+
+inline
+Node::~Node()
+{
+	if (_world) {
+		sord_node_free(_c_obj);
+	}
+}
+
+
+inline std::string
+Node::to_string() const
+{
+	return std::string(to_c_string());
+}
+
+
+inline const char*
+Node::to_c_string() const
+{
+	return (const char*)sord_node_get_string(_c_obj);
+}
+
+inline const uint8_t*
+Node::to_u_string() const
+{
+	return sord_node_get_string(_c_obj);
+}
+
+inline bool
+Node::is_literal_type(const char* type_uri) const
+{
+	if (_c_obj && sord_node_get_type(_c_obj) == SORD_LITERAL) {
+		SordNode datatype = sord_node_get_datatype(_c_obj);
+		if (datatype && !strcmp((const char*)sord_node_get_string(datatype),
+		                        type_uri))
+			return true;
+	}
+	return false;
+}
+
+inline int
+Node::to_int() const
+{
+	assert(is_int());
+	std::locale c_locale("C");
+	std::stringstream ss((const char*)sord_node_get_string(_c_obj));
+	ss.imbue(c_locale);
+	int i = 0;
+	ss >> i;
+	return i;
+}
+
+inline float
+Node::to_float() const
+{
+	assert(is_float());
+	std::locale c_locale("C");
+	std::stringstream ss((const char*)sord_node_get_string(_c_obj));
+	ss.imbue(c_locale);
+	float f = 0.0f;
+	ss >> f;
+	return f;
+}
+
+inline bool
+Node::to_bool() const
+{
+	assert(is_bool());
+	return !strcmp((const char*)sord_node_get_string(_c_obj), "true");
+}
+
+struct Iter : public Wrapper<SordIter> {
+	inline Iter(World& world, SordIter c_obj)
+		: Wrapper<SordIter>(c_obj), _world(world) {}
+	inline ~Iter() { sord_iter_free(_c_obj); }
+	inline bool end()  const { return sord_iter_end(_c_obj); }
+	inline bool next() const { return sord_iter_next(_c_obj); }
+	inline Iter& operator++() { assert(!end()); next(); return *this; }
+	inline Node get_subject() const {
+		SordQuad quad;
+		sord_iter_get(_c_obj, quad);
+		return Node(_world, quad[SORD_SUBJECT]);
+	}
+	inline Node get_predicate() const {
+		SordQuad quad;
+		sord_iter_get(_c_obj, quad);
+		return Node(_world, quad[SORD_PREDICATE]);
+	}
+	inline Node get_object() const {
+		SordQuad quad;
+		sord_iter_get(_c_obj, quad);
+		return Node(_world, quad[SORD_OBJECT]);
+	}
+	World& _world;
+};
+
+
+/** An RDF Model (collection of triples).
+ */
+class Model : public boost::noncopyable, public Wrapper<SordModel> {
+public:
+	inline Model(World& world, const Glib::ustring& base_uri=".");
+	inline ~Model();
+
+	inline const Node& base_uri() const { return _base; }
+
+	inline void load_file(const Glib::ustring& uri);
+
+	inline void load_string(const char*          str,
+	                        size_t               len,
+	                        const Glib::ustring& base_uri,
+	                        const std::string    lang = "turtle");
+
+	inline void  write_to_file_handle(FILE* fd, const char* lang);
+	inline void  write_to_file(const Glib::ustring& uri, const char* lang);
+	inline char* write_to_string(const char* lang);
+
+	inline void add_statement(const Node& subject,
+	                          const Node& predicate,
+	                          const Node& object);
+
+	inline Iter find(const Node& subject,
+	                 const Node& predicate,
+	                 const Node& object);
+
+	inline World& world() const { return _world; }
+
+private:
+	World&     _world;
+	Node       _base;
+	SerdWriter _writer;
+	size_t     _next_blank_id;
+};
+
+/** Create an empty in-memory RDF model.
+ */
+inline
+Model::Model(World& world, const Glib::ustring& base_uri)
+	: _world(world)
+	, _base(world, Node::RESOURCE, base_uri)
+	, _writer(NULL)
+{
+	// FIXME: parameters
+	_c_obj = sord_new(_world.world(), SORD_SPO|SORD_OPS, true);
+}
+
+inline void
+Model::load_string(const char*          str,
+                   size_t               len,
+                   const Glib::ustring& base_uri,
+                   const std::string    lang)
+{
+	// TODO
+}
+
+inline Model::~Model()
+{
+	sord_free(_c_obj);
+}
+
+inline void
+Model::load_file(const Glib::ustring& data_uri)
+{
+	// FIXME: blank prefix
+	sord_read_file(_c_obj, (const uint8_t*)data_uri.c_str(), NULL,
+	               (const uint8_t*)"b");
+}
+
+inline void
+Model::write_to_file_handle(FILE* fd, const char* lang)
+{
+	sord_write_file_handle(_c_obj,
+	                       _world.prefixes().c_obj(),
+	                       fd,
+	                       _base.to_u_string(),
+	                       NULL,
+	                       NULL);
+}
+
+inline void
+Model::write_to_file(const Glib::ustring& uri, const char* lang)
+{
+	sord_write_file(_c_obj,
+	                _world.prefixes().c_obj(),
+	                (const uint8_t*)uri.c_str(),
+	                NULL,
+	                NULL);
+}
+
+inline char*
+Model::write_to_string(const char* lang)
+{
+	std::cerr << "TODO: serialise" << std::endl;
+	return NULL;
+}
+
+inline void
+Model::add_statement(const Node& subject,
+                     const Node& predicate,
+                     const Node& object)
+{
+	SordQuad quad = { subject.c_obj(),
+	                  predicate.c_obj(),
+	                  object.c_obj(),
+	                  NULL };
+
+	sord_add(_c_obj, quad);
+}
+
+inline Iter
+Model::find(const Node& subject,
+            const Node& predicate,
+            const Node& object)
+{
+	SordQuad quad = { subject.c_obj(),
+	                  predicate.c_obj(),
+	                  object.c_obj(),
+	                  NULL };
+
+	return Iter(_world, sord_find(_c_obj, quad));
+}
+
+} // namespace Sord
+
+#endif // SORD_SORDMM_HPP
+