memory.hpp

/*
  Copyright (c) 2013, Randolph Voorhies, Shane Grant
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
      * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
      * Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
      * Neither the name of cereal nor the
        names of its contributors may be used to endorse or promote products
        derived from this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef CEREAL_TYPES_SHARED_PTR_HPP_
#define CEREAL_TYPES_SHARED_PTR_HPP_

#include <cereal/cereal.hpp>
#include <memory>

namespace cereal
{
  namespace memory_detail
  {

    template<class T>
    struct PtrWrapper
    {
      PtrWrapper(T && p) : ptr(std::forward<T>(p)) {}
      T & ptr;
    };


    template<class T> inline
    PtrWrapper<T> make_ptr_wrapper(T && t)
    {
      return {std::forward<T>(t)};
    }
  }

  template <class Archive, class T> inline
  typename std::enable_if<!std::is_polymorphic<T>::value, void>::type
  save( Archive & ar, std::shared_ptr<T> const & ptr )
  {
    ar( _CEREAL_NVP("ptr_wrapper", memory_detail::make_ptr_wrapper( ptr )) );
  }

  template <class Archive, class T> inline
  typename std::enable_if<!std::is_polymorphic<T>::value, void>::type
  load( Archive & ar, std::shared_ptr<T> & ptr )
  {
    ar( memory_detail::make_ptr_wrapper( ptr ) );
  }

  template <class Archive, class T> inline
  typename std::enable_if<!std::is_polymorphic<T>::value, void>::type
  save( Archive & ar, std::weak_ptr<T> const & ptr )
  {
    auto sptr = ptr.lock();
    ar( _CEREAL_NVP("ptr_wrapper", memory_detail::make_ptr_wrapper( sptr )) );
  }

  template <class Archive, class T> inline
  typename std::enable_if<!std::is_polymorphic<T>::value, void>::type
  load( Archive & ar, std::weak_ptr<T> & ptr )
  {
    std::shared_ptr<T> sptr;
    ar( memory_detail::make_ptr_wrapper( sptr ) );
    ptr = sptr;
  }

  template <class Archive, class T, class D> inline
  typename std::enable_if<!std::is_polymorphic<T>::value, void>::type
  save( Archive & ar, std::unique_ptr<T, D> const & ptr )
  {
    ar( _CEREAL_NVP("ptr_wrapper", memory_detail::make_ptr_wrapper( ptr )) );
  }

  template <class Archive, class T, class D> inline
  typename std::enable_if<!std::is_polymorphic<T>::value, void>::type
  load( Archive & ar, std::unique_ptr<T, D> & ptr )
  {
    ar( memory_detail::make_ptr_wrapper( ptr ) );
  }

  // ######################################################################
  // Pointer wrapper implementations follow below

  template <class Archive, class T> inline
  void save( Archive & ar, memory_detail::PtrWrapper<std::shared_ptr<T> const &> const & wrapper )
  {
    auto & ptr = wrapper.ptr;

    uint32_t id = ar.registerSharedPointer( ptr.get() );
    ar( _CEREAL_NVP("id", id) );

    if( id & detail::msb_32bit )
    {
      ar( _CEREAL_NVP("data", *ptr) );
    }
  }

  template <class Archive, class T> inline
  typename std::enable_if<traits::has_load_and_allocate<T, Archive>(), void>::type
  load( Archive & ar, memory_detail::PtrWrapper<std::shared_ptr<T> &> & wrapper )
  {
    auto & ptr = wrapper.ptr;

    uint32_t id;

    ar( id );

    if( id & detail::msb_32bit )
    {
      ptr.reset( detail::Load<T, Archive>::load_andor_allocate( ar ) );
      ar.registerSharedPointer(id, ptr);
    }
    else
    {
      ptr = std::static_pointer_cast<T>(ar.getSharedPointer(id));
    }
  }

  template <class Archive, class T> inline
  typename std::enable_if<!traits::has_load_and_allocate<T, Archive>(), void>::type
  load( Archive & ar, memory_detail::PtrWrapper<std::shared_ptr<T> &> & wrapper )
  {
    auto & ptr = wrapper.ptr;

    uint32_t id;

    ar( id );

    if( id & detail::msb_32bit )
    {
      ptr.reset( detail::Load<T, Archive>::load_andor_allocate( ar ) );
      ar( *ptr );
      ar.registerSharedPointer(id, ptr);
    }
    else
    {
      ptr = std::static_pointer_cast<T>(ar.getSharedPointer(id));
    }
  }

  template <class Archive, class T, class D> inline
  void save( Archive & ar, memory_detail::PtrWrapper<std::unique_ptr<T, D> const &> const & wrapper )
  {
    auto & ptr = wrapper.ptr;

    // unique_ptr get one byte of metadata which signifies whether they were a nullptr
    // 0 == nullptr
    // 1 == not null

    if( !ptr )
      ar( _CEREAL_NVP("valid", uint8_t(0)) );
    else
    {
      ar( _CEREAL_NVP("valid", uint8_t(1)) );
      ar( _CEREAL_NVP("data", *ptr) );
    }
  }

  template <class Archive, class T, class D> inline
  typename std::enable_if<traits::has_load_and_allocate<T, Archive>(), void>::type
  load( Archive & ar, memory_detail::PtrWrapper<std::unique_ptr<T, D> &> & wrapper )
  {
    uint8_t isValid;
    ar( isValid );

    auto & ptr = wrapper.ptr;

    if( isValid )
      ptr.reset( detail::Load<T, Archive>::load_andor_allocate( ar ) );
    else
      ptr.reset( nullptr );
  }

  template <class Archive, class T, class D> inline
  typename std::enable_if<!traits::has_load_and_allocate<T, Archive>(), void>::type
  load( Archive & ar, memory_detail::PtrWrapper<std::unique_ptr<T, D> &> & wrapper )
  {
    uint8_t isValid;
    ar( isValid );

    auto & ptr = wrapper.ptr;

    if( isValid )
    {
      ptr.reset( detail::Load<T, Archive>::load_andor_allocate( ar ) );
      ar( *ptr );
    }
    else
    {
      ptr.reset( nullptr );
    }
  }
} // namespace cereal

#endif // CEREAL_TYPES_SHARED_PTR_HPP_