boost/serialization/shared_ptr_helper.hpp

   1 #ifndef BOOST_SERIALIZATION_SHARED_PTR_HELPER_HPP
   2 #define BOOST_SERIALIZATION_SHARED_PTR_HELPER_HPP
   3
   4 // MS compatible compilers support #pragma once
   5 #if defined(_MSC_VER)
   6 # pragma once
   7 #endif
   8
   9 /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
  10 // shared_ptr_helper.hpp: serialization for boost shared pointern
  11
  12 // (C) Copyright 2004-2009 Robert Ramey, Martin Ecker and Takatoshi Kondo
  13 // Use, modification and distribution is subject to the Boost Software
  14 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  15 // http://www.boost.org/LICENSE_1_0.txt)
  16
  17 //  See http://www.boost.org for updates, documentation, and revision history.
  18
  19 #include <map>
  20 #include <list>
  21 #include <utility>
  22 #include <cstddef> // NULL
  23
  24 #include <boost/config.hpp>
  25 #include <boost/shared_ptr.hpp>
  26 #include <boost/type_traits/is_polymorphic.hpp>
  27 #include <boost/mpl/if.hpp>
  28
  29 #include <boost/serialization/singleton.hpp>
  30 #include <boost/serialization/extended_type_info.hpp>
  31 #include <boost/serialization/throw_exception.hpp>
  32 #include <boost/serialization/type_info_implementation.hpp>
  33 #include <boost/archive/archive_exception.hpp>
  34
  35 namespace boost_132 {
  36     template<class T> class shared_ptr;
  37 }
  38 namespace boost {
  39 namespace serialization {
  40
  41 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
  42 template<class Archive, template<class U> class SPT >
  43 void load(
  44     Archive & ar,
  45     SPT< class U > &t,
  46     const unsigned int file_version
  47 );
  48 #endif
  49
  50 /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
  51 // a common class for holding various types of shared pointers
  52
  53 template<template<class T> class SPT>
  54 class shared_ptr_helper {
  55     typedef std::map<
  56         const void *, // address of object
  57         SPT<const void> // address shared ptr to single instance
  58     > object_shared_pointer_map;
  59
  60     // list of shared_pointers create accessable by raw pointer. This
  61     // is used to "match up" shared pointers loaded at different
  62     // points in the archive. Note, we delay construction until
  63     // it is actually used since this is by default included as
  64     // a "mix-in" even if shared_ptr isn't used.
  65     object_shared_pointer_map * m_o_sp;
  66
  67     struct null_deleter {
  68         void operator()(void const *) const {}
  69     };
  70
  71 #if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) \
  72 || defined(BOOST_MSVC) \
  73 || defined(__SUNPRO_CC)
  74 public:
  75 #else
  76     template<class Archive, class U>
  77     friend void boost::serialization::load(
  78         Archive & ar,
  79         SPT< U > &t,
  80         const unsigned int file_version
  81     );
  82 #endif
  83
  84     #ifdef BOOST_SERIALIZATION_SHARED_PTR_132_HPP
  85     // list of loaded pointers.  This is used to be sure that the pointers
  86     // stay around long enough to be "matched" with other pointers loaded
  87     // by the same archive.  These are created with a "null_deleter" so that
  88     // when this list is destroyed - the underlaying raw pointers are not
  89     // destroyed.  This has to be done because the pointers are also held by
  90     // new system which is disjoint from this set.  This is implemented
  91     // by a change in load_construct_data below.  It makes this file suitable
  92     // only for loading pointers into a 1.33 or later boost system.
  93     std::list<boost_132::shared_ptr<const void> > * m_pointers_132;
  94     void
  95     append(const boost_132::shared_ptr<const void> & t){
  96         if(NULL == m_pointers_132)
  97             m_pointers_132 = new std::list<boost_132::shared_ptr<const void> >;
  98         m_pointers_132->push_back(t);
  99     }
 100     #endif
 101
 102     struct non_polymorphic {
 103         template<class U>
 104         static const boost::serialization::extended_type_info *
 105         get_object_type(U & ){
 106             return & boost::serialization::singleton<
 107                 typename
 108                 boost::serialization::type_info_implementation< U >::type
 109             >::get_const_instance();
 110         }
 111     };
 112     struct polymorphic {
 113         template<class U>
 114         static const boost::serialization::extended_type_info *
 115         get_object_type(U & u){
 116             return boost::serialization::singleton<
 117                 typename
 118                 boost::serialization::type_info_implementation< U >::type
 119             >::get_const_instance().get_derived_extended_type_info(u);
 120         }
 121     };
 122
 123 public:
 124     template<class T>
 125     void reset(SPT< T > & s, T * t){
 126         if(NULL == t){
 127             s.reset();
 128             return;
 129         }
 130         const boost::serialization::extended_type_info * this_type
 131             = & boost::serialization::type_info_implementation< T >::type
 132                     ::get_const_instance();
 133
 134         // get pointer to the most derived object's eti.  This is effectively
 135         // the object type identifer
 136         typedef typename mpl::if_<
 137             is_polymorphic< T >,
 138             polymorphic,
 139             non_polymorphic
 140         >::type type;
 141
 142         const boost::serialization::extended_type_info * true_type
 143             = type::get_object_type(*t);
 144
 145         // note:if this exception is thrown, be sure that derived pointern
 146         // is either registered or exported.
 147         if(NULL == true_type)
 148             boost::serialization::throw_exception(
 149                 boost::archive::archive_exception(
 150                     boost::archive::archive_exception::unregistered_class,
 151                     this_type->get_debug_info()
 152                 )
 153             );
 154         // get void pointer to the most derived type
 155         // this uniquely identifies the object referred to
 156         // oid = "object identifier"
 157         const void * oid = void_downcast(
 158             *true_type,
 159             *this_type,
 160             t
 161         );
 162         if(NULL == oid)
 163             boost::serialization::throw_exception(
 164                 boost::archive::archive_exception(
 165                     boost::archive::archive_exception::unregistered_cast,
 166                     true_type->get_debug_info(),
 167                     this_type->get_debug_info()
 168                 )
 169             );
 170
 171         // make tracking array if necessary
 172         if(NULL == m_o_sp)
 173             m_o_sp = new object_shared_pointer_map;
 174
 175         typename object_shared_pointer_map::iterator i = m_o_sp->find(oid);
 176
 177         // if it's a new object
 178         if(i == m_o_sp->end()){
 179             s.reset(t);
 180             std::pair<typename object_shared_pointer_map::iterator, bool> result;
 181             result = m_o_sp->insert(std::make_pair(oid, s));
 182             BOOST_ASSERT(result.second);
 183         }
 184         // if the object has already been seen
 185         else{
 186             s = SPT<T>(i->second, t);
 187         }
 188     }
 189
 190     shared_ptr_helper() :
 191         m_o_sp(NULL)
 192         #ifdef BOOST_SERIALIZATION_SHARED_PTR_132_HPP
 193             , m_pointers_132(NULL)
 194         #endif
 195     {}
 196     virtual ~shared_ptr_helper(){
 197         if(NULL != m_o_sp)
 198             delete m_o_sp;
 199         #ifdef BOOST_SERIALIZATION_SHARED_PTR_132_HPP
 200         if(NULL != m_pointers_132)
 201             delete m_pointers_132;
 202         #endif
 203     }
 204 };
 205
 206 } // namespace serialization
 207 } // namespace boost
 208
 209 #endif // BOOST_SERIALIZATION_SHARED_PTR_HELPER_HPP