boost/graph/named_graph.hpp
// Copyright (C) 2007 Douglas Gregor // Use, modification and distribution is subject to the Boost Software // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) // Provides support for named vertices in graphs, allowing one to more // easily associate unique external names (URLs, city names, employee // ID numbers, etc.) with the vertices of a graph. #ifndef BOOST_GRAPH_NAMED_GRAPH_HPP #define BOOST_GRAPH_NAMED_GRAPH_HPP #include <boost/config.hpp> #include <boost/static_assert.hpp> #include <boost/functional/hash.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/properties.hpp> #include <boost/multi_index/hashed_index.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index_container.hpp> #include <boost/optional.hpp> #include <boost/pending/property.hpp> // for boost::lookup_one_property #include <boost/pending/container_traits.hpp> #include <boost/throw_exception.hpp> #include <boost/tuple/tuple.hpp> // for boost::make_tuple #include <boost/type_traits/is_same.hpp> #include <boost/type_traits/is_base_of.hpp> #include <boost/type_traits/remove_cv.hpp> #include <boost/type_traits/remove_reference.hpp> #include <boost/utility/enable_if.hpp> #include <functional> // for std::equal_to #include <stdexcept> // for std::runtime_error #include <utility> // for std::pair namespace boost { namespace graph { /******************************************************************* * User-customized traits * *******************************************************************/ /** * @brief Trait used to extract the internal vertex name from a vertex * property. * * To enable the use of internal vertex names in a graph type, * specialize the @c internal_vertex_name trait for your graph * property (e.g., @c a City class, which stores information about the * vertices in a road map). */ template < typename VertexProperty > struct internal_vertex_name { /** * The @c type field provides a function object that extracts a key * from the @c VertexProperty. The function object type must have a * nested @c result_type that provides the type of the key. For * more information, see the @c KeyExtractor concept in the * Boost.MultiIndex documentation: @c type must either be @c void * (if @c VertexProperty does not have an internal vertex name) or * a model of @c KeyExtractor. */ typedef void type; }; /** * Extract the internal vertex name from a @c property structure by * looking at its base. */ template < typename Tag, typename T, typename Base > struct internal_vertex_name< property< Tag, T, Base > > : internal_vertex_name< Base > { }; /** * Construct an instance of @c VertexProperty directly from its * name. This function object should be used within the @c * internal_vertex_constructor trait. */ template < typename VertexProperty > struct vertex_from_name { private: typedef typename internal_vertex_name< VertexProperty >::type extract_name_type; typedef typename remove_cv< typename remove_reference< typename extract_name_type::result_type >::type >::type vertex_name_type; public: typedef vertex_name_type argument_type; typedef VertexProperty result_type; VertexProperty operator()(const vertex_name_type& name) { return VertexProperty(name); } }; /** * Throw an exception whenever one tries to construct a @c * VertexProperty instance from its name. */ template < typename VertexProperty > struct cannot_add_vertex { private: typedef typename internal_vertex_name< VertexProperty >::type extract_name_type; typedef typename remove_cv< typename remove_reference< typename extract_name_type::result_type >::type >::type vertex_name_type; public: typedef vertex_name_type argument_type; typedef VertexProperty result_type; VertexProperty operator()(const vertex_name_type&) { boost::throw_exception( std::runtime_error("add_vertex: " "unable to create a vertex from its name")); } }; /** * @brief Trait used to construct an instance of a @c VertexProperty, * which is a class type that stores the properties associated with a * vertex in a graph, from just the name of that vertex property. This * operation is used when an operation is required to map from a * vertex name to a vertex descriptor (e.g., to add an edge outgoing * from that vertex), but no vertex by the name exists. The function * object provided by this trait will be used to add new vertices * based only on their names. Since this cannot be done for arbitrary * types, the default behavior is to throw an exception when this * routine is called, which requires that all named vertices be added * before adding any edges by name. */ template < typename VertexProperty > struct internal_vertex_constructor { /** * The @c type field provides a function object that constructs a * new instance of @c VertexProperty from the name of the vertex (as * determined by @c internal_vertex_name). The function object shall * accept a vertex name and return a @c VertexProperty. Predefined * options include: * * @c vertex_from_name<VertexProperty>: construct an instance of * @c VertexProperty directly from the name. * * @c cannot_add_vertex<VertexProperty>: the default value, which * throws an @c std::runtime_error if one attempts to add a vertex * given just the name. */ typedef cannot_add_vertex< VertexProperty > type; }; /** * Extract the internal vertex constructor from a @c property structure by * looking at its base. */ template < typename Tag, typename T, typename Base > struct internal_vertex_constructor< property< Tag, T, Base > > : internal_vertex_constructor< Base > { }; /******************************************************************* * Named graph mixin * *******************************************************************/ /** * named_graph is a mixin that provides names for the vertices of a * graph, including a mapping from names to vertices. Graph types that * may or may not be have vertex names (depending on the properties * supplied by the user) should use maybe_named_graph. * * Template parameters: * * Graph: the graph type that derives from named_graph * * Vertex: the type of a vertex descriptor in Graph. Note: we cannot * use graph_traits here, because the Graph is not yet defined. * * VertexProperty: the type stored with each vertex in the Graph. */ template < typename Graph, typename Vertex, typename VertexProperty > class named_graph { public: /// The type of the function object that extracts names from vertex /// properties. typedef typename internal_vertex_name< VertexProperty >::type extract_name_type; /// The type of the "bundled" property, from which the name can be /// extracted. typedef typename lookup_one_property< VertexProperty, vertex_bundle_t >::type bundled_vertex_property_type; /// The type of the function object that generates vertex properties /// from names, for the implicit addition of vertices. typedef typename internal_vertex_constructor< VertexProperty >::type vertex_constructor_type; /// The type used to name vertices in the graph typedef typename remove_cv< typename remove_reference< typename extract_name_type::result_type >::type >::type vertex_name_type; /// The type of vertex descriptors in the graph typedef Vertex vertex_descriptor; private: /// Key extractor for use with the multi_index_container struct extract_name_from_vertex { typedef vertex_name_type result_type; extract_name_from_vertex( Graph& graph, const extract_name_type& extract) : graph(graph), extract(extract) { } const result_type& operator()(Vertex vertex) const { return extract(graph[vertex]); } Graph& graph; extract_name_type extract; }; public: /// The type that maps names to vertices typedef multi_index::multi_index_container< Vertex, multi_index::indexed_by< multi_index::hashed_unique< multi_index::tag< vertex_name_t >, extract_name_from_vertex > > > named_vertices_type; /// The set of vertices, indexed by name typedef typename named_vertices_type::template index< vertex_name_t >::type vertices_by_name_type; /// Construct an instance of the named graph mixin, using the given /// function object to extract a name from the bundled property /// associated with a vertex. named_graph(const extract_name_type& extract = extract_name_type(), const vertex_constructor_type& vertex_constructor = vertex_constructor_type()); /// Notify the named_graph that we have added the given vertex. The /// name of the vertex will be added to the mapping. void added_vertex(Vertex vertex); /// Notify the named_graph that we are removing the given /// vertex. The name of the vertex will be removed from the mapping. template < typename VertexIterStability > void removing_vertex(Vertex vertex, VertexIterStability); /// Notify the named_graph that we are clearing the graph. /// This will clear out all of the name->vertex mappings void clearing_graph(); /// Retrieve the derived instance Graph& derived() { return static_cast< Graph& >(*this); } const Graph& derived() const { return static_cast< const Graph& >(*this); } /// Extract the name from a vertex property instance typename extract_name_type::result_type extract_name( const bundled_vertex_property_type& property); /// Search for a vertex that has the given property (based on its /// name) optional< vertex_descriptor > vertex_by_property( const bundled_vertex_property_type& property); /// Mapping from names to vertices named_vertices_type named_vertices; /// Constructs a vertex from the name of that vertex vertex_constructor_type vertex_constructor; }; /// Helper macro containing the template parameters of named_graph #define BGL_NAMED_GRAPH_PARAMS \ typename Graph, typename Vertex, typename VertexProperty /// Helper macro containing the named_graph<...> instantiation #define BGL_NAMED_GRAPH named_graph< Graph, Vertex, VertexProperty > template < BGL_NAMED_GRAPH_PARAMS > BGL_NAMED_GRAPH::named_graph(const extract_name_type& extract, const vertex_constructor_type& vertex_constructor) : named_vertices(typename named_vertices_type::ctor_args_list( boost::make_tuple(boost::make_tuple(0, // initial number of buckets extract_name_from_vertex(derived(), extract), boost::hash< vertex_name_type >(), std::equal_to< vertex_name_type >())))) , vertex_constructor(vertex_constructor) { } template < BGL_NAMED_GRAPH_PARAMS > inline void BGL_NAMED_GRAPH::added_vertex(Vertex vertex) { named_vertices.insert(vertex); } template < BGL_NAMED_GRAPH_PARAMS > template < typename VertexIterStability > inline void BGL_NAMED_GRAPH::removing_vertex( Vertex vertex, VertexIterStability) { BOOST_STATIC_ASSERT_MSG( (boost::is_base_of< boost::graph_detail::stable_tag, VertexIterStability >::value), "Named graphs cannot use vecS as vertex container and remove " "vertices; the lack of vertex descriptor stability (which iterator " "stability is a proxy for) means that the name -> vertex mapping " "would need to be completely rebuilt after each deletion. See " "https://svn.boost.org/trac/boost/ticket/7863 for more information " "and a test case."); typedef typename BGL_NAMED_GRAPH::vertex_name_type vertex_name_type; const vertex_name_type& vertex_name = extract_name(derived()[vertex]); named_vertices.erase(vertex_name); } template < BGL_NAMED_GRAPH_PARAMS > inline void BGL_NAMED_GRAPH::clearing_graph() { named_vertices.clear(); } template < BGL_NAMED_GRAPH_PARAMS > typename BGL_NAMED_GRAPH::extract_name_type::result_type BGL_NAMED_GRAPH::extract_name(const bundled_vertex_property_type& property) { return named_vertices.key_extractor().extract(property); } template < BGL_NAMED_GRAPH_PARAMS > optional< typename BGL_NAMED_GRAPH::vertex_descriptor > BGL_NAMED_GRAPH::vertex_by_property( const bundled_vertex_property_type& property) { return find_vertex(extract_name(property), *this); } /// Retrieve the vertex associated with the given name template < BGL_NAMED_GRAPH_PARAMS > optional< Vertex > find_vertex( typename BGL_NAMED_GRAPH::vertex_name_type const& name, const BGL_NAMED_GRAPH& g) { typedef typename BGL_NAMED_GRAPH::vertices_by_name_type vertices_by_name_type; // Retrieve the set of vertices indexed by name vertices_by_name_type const& vertices_by_name = g.named_vertices.template get< vertex_name_t >(); /// Look for a vertex with the given name typename vertices_by_name_type::const_iterator iter = vertices_by_name.find(name); if (iter == vertices_by_name.end()) return optional< Vertex >(); // vertex not found else return *iter; } /// Retrieve the vertex associated with the given name, or add a new /// vertex with that name if no such vertex is available. /// Note: This is enabled only when the vertex property type is different /// from the vertex name to avoid ambiguous overload problems with /// the add_vertex() function that takes a vertex property. template < BGL_NAMED_GRAPH_PARAMS > typename disable_if< is_same< typename BGL_NAMED_GRAPH::vertex_name_type, VertexProperty >, Vertex >::type add_vertex(typename BGL_NAMED_GRAPH::vertex_name_type const& name, BGL_NAMED_GRAPH& g) { if (optional< Vertex > vertex = find_vertex(name, g)) /// We found the vertex, so return it return *vertex; else /// There is no vertex with the given name, so create one return add_vertex(g.vertex_constructor(name), g.derived()); } /// Add an edge using vertex names to refer to the vertices template < BGL_NAMED_GRAPH_PARAMS > std::pair< typename graph_traits< Graph >::edge_descriptor, bool > add_edge( typename BGL_NAMED_GRAPH::vertex_name_type const& u_name, typename BGL_NAMED_GRAPH::vertex_name_type const& v_name, BGL_NAMED_GRAPH& g) { return add_edge(add_vertex(u_name, g.derived()), add_vertex(v_name, g.derived()), g.derived()); } /// Add an edge using vertex descriptors or names to refer to the vertices template < BGL_NAMED_GRAPH_PARAMS > std::pair< typename graph_traits< Graph >::edge_descriptor, bool > add_edge( typename BGL_NAMED_GRAPH::vertex_descriptor const& u, typename BGL_NAMED_GRAPH::vertex_name_type const& v_name, BGL_NAMED_GRAPH& g) { return add_edge(u, add_vertex(v_name, g.derived()), g.derived()); } /// Add an edge using vertex descriptors or names to refer to the vertices template < BGL_NAMED_GRAPH_PARAMS > std::pair< typename graph_traits< Graph >::edge_descriptor, bool > add_edge( typename BGL_NAMED_GRAPH::vertex_name_type const& u_name, typename BGL_NAMED_GRAPH::vertex_descriptor const& v, BGL_NAMED_GRAPH& g) { return add_edge(add_vertex(u_name, g.derived()), v, g.derived()); } // Overloads to support EdgeMutablePropertyGraph graphs template < BGL_NAMED_GRAPH_PARAMS > std::pair< typename graph_traits< Graph >::edge_descriptor, bool > add_edge( typename BGL_NAMED_GRAPH::vertex_descriptor const& u, typename BGL_NAMED_GRAPH::vertex_name_type const& v_name, typename edge_property_type< Graph >::type const& p, BGL_NAMED_GRAPH& g) { return add_edge(u, add_vertex(v_name, g.derived()), p, g.derived()); } template < BGL_NAMED_GRAPH_PARAMS > std::pair< typename graph_traits< Graph >::edge_descriptor, bool > add_edge( typename BGL_NAMED_GRAPH::vertex_name_type const& u_name, typename BGL_NAMED_GRAPH::vertex_descriptor const& v, typename edge_property_type< Graph >::type const& p, BGL_NAMED_GRAPH& g) { return add_edge(add_vertex(u_name, g.derived()), v, p, g.derived()); } template < BGL_NAMED_GRAPH_PARAMS > std::pair< typename graph_traits< Graph >::edge_descriptor, bool > add_edge( typename BGL_NAMED_GRAPH::vertex_name_type const& u_name, typename BGL_NAMED_GRAPH::vertex_name_type const& v_name, typename edge_property_type< Graph >::type const& p, BGL_NAMED_GRAPH& g) { return add_edge(add_vertex(u_name, g.derived()), add_vertex(v_name, g.derived()), p, g.derived()); } #undef BGL_NAMED_GRAPH #undef BGL_NAMED_GRAPH_PARAMS /******************************************************************* * Maybe named graph mixin * *******************************************************************/ /** * A graph mixin that can provide a mapping from names to vertices, * and use that mapping to simplify creation and manipulation of * graphs. */ template < typename Graph, typename Vertex, typename VertexProperty, typename ExtractName = typename internal_vertex_name< VertexProperty >::type > struct maybe_named_graph : public named_graph< Graph, Vertex, VertexProperty > { }; /** * A graph mixin that can provide a mapping from names to vertices, * and use that mapping to simplify creation and manipulation of * graphs. This partial specialization turns off this functionality * when the @c VertexProperty does not have an internal vertex name. */ template < typename Graph, typename Vertex, typename VertexProperty > struct maybe_named_graph< Graph, Vertex, VertexProperty, void > { /// The type of the "bundled" property, from which the name can be /// extracted. typedef typename lookup_one_property< VertexProperty, vertex_bundle_t >::type bundled_vertex_property_type; /// Notify the named_graph that we have added the given vertex. This /// is a no-op. void added_vertex(Vertex) {} /// Notify the named_graph that we are removing the given /// vertex. This is a no-op. template < typename VertexIterStability > void removing_vertex(Vertex, VertexIterStability) { } /// Notify the named_graph that we are clearing the graph. This is a /// no-op. void clearing_graph() {} /// Search for a vertex that has the given property (based on its /// name). This always returns an empty optional<> optional< Vertex > vertex_by_property( const bundled_vertex_property_type&) { return optional< Vertex >(); } }; } } // end namespace boost::graph #endif // BOOST_GRAPH_NAMED_GRAPH_HPP