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jujube/include/cereal/access.hpp
2020-02-11 22:11:37 +01:00

352 lines
14 KiB
C++

/*! \file access.hpp
\brief Access control and default construction */
/*
Copyright (c) 2014, 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 RANDOLPH VOORHIES OR SHANE GRANT 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_ACCESS_HPP_
#define CEREAL_ACCESS_HPP_
#include <type_traits>
#include <iostream>
#include <cstdint>
#include <functional>
#include "cereal/macros.hpp"
#include "cereal/specialize.hpp"
#include "cereal/details/helpers.hpp"
namespace cereal
{
// ######################################################################
//! A class that allows cereal to load smart pointers to types that have no default constructor
/*! If your class does not have a default constructor, cereal will not be able
to load any smart pointers to it unless you overload LoadAndConstruct
for your class, and provide an appropriate load_and_construct method. You can also
choose to define a member static function instead of specializing this class.
The specialization of LoadAndConstruct must be placed within the cereal namespace:
@code{.cpp}
struct MyType
{
MyType( int x ); // note: no default ctor
int myX;
// Define a serialize or load/save pair as you normally would
template <class Archive>
void serialize( Archive & ar )
{
ar( myX );
}
};
// Provide a specialization for LoadAndConstruct for your type
namespace cereal
{
template <> struct LoadAndConstruct<MyType>
{
// load_and_construct will be passed the archive that you will be loading
// from as well as a construct object which you can use as if it were the
// constructor for your type. cereal will handle all memory management for you.
template <class Archive>
static void load_and_construct( Archive & ar, cereal::construct<MyType> & construct )
{
int x;
ar( x );
construct( x );
}
// if you require versioning, simply add a const std::uint32_t as the final parameter, e.g.:
// load_and_construct( Archive & ar, cereal::construct<MyType> & construct, std::uint32_t const version )
};
} // end namespace cereal
@endcode
Please note that just as in using external serialization functions, you cannot get
access to non-public members of your class by befriending cereal::access. If you
have the ability to modify the class you wish to serialize, it is recommended that you
use member serialize functions and a static member load_and_construct function.
load_and_construct functions, regardless of whether they are static members of your class or
whether you create one in the LoadAndConstruct specialization, have the following signature:
@code{.cpp}
// generally Archive will be templated, but it can be specific if desired
template <class Archive>
static void load_and_construct( Archive & ar, cereal::construct<MyType> & construct );
// with an optional last parameter specifying the version: const std::uint32_t version
@endcode
Versioning behaves the same way as it does for standard serialization functions.
@tparam T The type to specialize for
@ingroup Access */
template <class T>
struct LoadAndConstruct
{ };
// forward decl for construct
//! @cond PRIVATE_NEVERDEFINED
namespace memory_detail{ template <class Ar, class T> struct LoadAndConstructLoadWrapper; }
namespace boost_variant_detail{ template <class Ar, class T> struct LoadAndConstructLoadWrapper; }
//! @endcond
//! Used to construct types with no default constructor
/*! When serializing a type that has no default constructor, cereal
will attempt to call either the class static function load_and_construct
or the appropriate template specialization of LoadAndConstruct. cereal
will pass that function a reference to the archive as well as a reference
to a construct object which should be used to perform the allocation once
data has been appropriately loaded.
@code{.cpp}
struct MyType
{
// note the lack of default constructor
MyType( int xx, int yy );
int x, y;
double notInConstructor;
template <class Archive>
void serialize( Archive & ar )
{
ar( x, y );
ar( notInConstructor );
}
template <class Archive>
static void load_and_construct( Archive & ar, cereal::construct<MyType> & construct )
{
int x, y;
ar( x, y );
// use construct object to initialize with loaded data
construct( x, y );
// access to member variables and functions via -> operator
ar( construct->notInConstructor );
// could also do the above section by:
double z;
ar( z );
construct->notInConstructor = z;
}
};
@endcode
@tparam T The class type being serialized
*/
template <class T>
class construct
{
public:
//! Construct and initialize the type T with the given arguments
/*! This will forward all arguments to the underlying type T,
calling an appropriate constructor.
Calling this function more than once will result in an exception
being thrown.
@param args The arguments to the constructor for T
@throw Exception If called more than once */
template <class ... Args>
void operator()( Args && ... args );
// implementation deferred due to reliance on cereal::access
//! Get a reference to the initialized underlying object
/*! This must be called after the object has been initialized.
@return A reference to the initialized object
@throw Exception If called before initialization */
T * operator->()
{
if( !itsValid )
throw Exception("Object must be initialized prior to accessing members");
return itsPtr;
}
//! Returns a raw pointer to the initialized underlying object
/*! This is mainly intended for use with passing an instance of
a constructed object to cereal::base_class.
It is strongly recommended to avoid using this function in
any other circumstance.
@return A raw pointer to the initialized type */
T * ptr()
{
return operator->();
}
private:
template <class Ar, class TT> friend struct ::cereal::memory_detail::LoadAndConstructLoadWrapper;
template <class Ar, class TT> friend struct ::cereal::boost_variant_detail::LoadAndConstructLoadWrapper;
construct( T * p ) : itsPtr( p ), itsEnableSharedRestoreFunction( [](){} ), itsValid( false ) {}
construct( T * p, std::function<void()> enableSharedFunc ) : // g++4.7 ice with default lambda to std func
itsPtr( p ), itsEnableSharedRestoreFunction( enableSharedFunc ), itsValid( false ) {}
construct( construct const & ) = delete;
construct & operator=( construct const & ) = delete;
T * itsPtr;
std::function<void()> itsEnableSharedRestoreFunction;
bool itsValid;
};
// ######################################################################
//! A class that can be made a friend to give cereal access to non public functions
/*! If you desire non-public serialization functions within a class, cereal can only
access these if you declare cereal::access a friend.
@code{.cpp}
class MyClass
{
private:
friend class cereal::access; // gives access to the private serialize
template <class Archive>
void serialize( Archive & ar )
{
// some code
}
};
@endcode
@ingroup Access */
class access
{
public:
// ####### Standard Serialization ########################################
template<class Archive, class T> inline
static auto member_serialize(Archive & ar, T & t) -> decltype(t.CEREAL_SERIALIZE_FUNCTION_NAME(ar))
{ return t.CEREAL_SERIALIZE_FUNCTION_NAME(ar); }
template<class Archive, class T> inline
static auto member_save(Archive & ar, T const & t) -> decltype(t.CEREAL_SAVE_FUNCTION_NAME(ar))
{ return t.CEREAL_SAVE_FUNCTION_NAME(ar); }
template<class Archive, class T> inline
static auto member_save_non_const(Archive & ar, T & t) -> decltype(t.CEREAL_SAVE_FUNCTION_NAME(ar))
{ return t.CEREAL_SAVE_FUNCTION_NAME(ar); }
template<class Archive, class T> inline
static auto member_load(Archive & ar, T & t) -> decltype(t.CEREAL_LOAD_FUNCTION_NAME(ar))
{ return t.CEREAL_LOAD_FUNCTION_NAME(ar); }
template<class Archive, class T> inline
static auto member_save_minimal(Archive const & ar, T const & t) -> decltype(t.CEREAL_SAVE_MINIMAL_FUNCTION_NAME(ar))
{ return t.CEREAL_SAVE_MINIMAL_FUNCTION_NAME(ar); }
template<class Archive, class T> inline
static auto member_save_minimal_non_const(Archive const & ar, T & t) -> decltype(t.CEREAL_SAVE_MINIMAL_FUNCTION_NAME(ar))
{ return t.CEREAL_SAVE_MINIMAL_FUNCTION_NAME(ar); }
template<class Archive, class T, class U> inline
static auto member_load_minimal(Archive const & ar, T & t, U && u) -> decltype(t.CEREAL_LOAD_MINIMAL_FUNCTION_NAME(ar, std::forward<U>(u)))
{ return t.CEREAL_LOAD_MINIMAL_FUNCTION_NAME(ar, std::forward<U>(u)); }
// ####### Versioned Serialization #######################################
template<class Archive, class T> inline
static auto member_serialize(Archive & ar, T & t, const std::uint32_t version ) -> decltype(t.CEREAL_SERIALIZE_FUNCTION_NAME(ar, version))
{ return t.CEREAL_SERIALIZE_FUNCTION_NAME(ar, version); }
template<class Archive, class T> inline
static auto member_save(Archive & ar, T const & t, const std::uint32_t version ) -> decltype(t.CEREAL_SAVE_FUNCTION_NAME(ar, version))
{ return t.CEREAL_SAVE_FUNCTION_NAME(ar, version); }
template<class Archive, class T> inline
static auto member_save_non_const(Archive & ar, T & t, const std::uint32_t version ) -> decltype(t.CEREAL_SAVE_FUNCTION_NAME(ar, version))
{ return t.CEREAL_SAVE_FUNCTION_NAME(ar, version); }
template<class Archive, class T> inline
static auto member_load(Archive & ar, T & t, const std::uint32_t version ) -> decltype(t.CEREAL_LOAD_FUNCTION_NAME(ar, version))
{ return t.CEREAL_LOAD_FUNCTION_NAME(ar, version); }
template<class Archive, class T> inline
static auto member_save_minimal(Archive const & ar, T const & t, const std::uint32_t version) -> decltype(t.CEREAL_SAVE_MINIMAL_FUNCTION_NAME(ar, version))
{ return t.CEREAL_SAVE_MINIMAL_FUNCTION_NAME(ar, version); }
template<class Archive, class T> inline
static auto member_save_minimal_non_const(Archive const & ar, T & t, const std::uint32_t version) -> decltype(t.CEREAL_SAVE_MINIMAL_FUNCTION_NAME(ar, version))
{ return t.CEREAL_SAVE_MINIMAL_FUNCTION_NAME(ar, version); }
template<class Archive, class T, class U> inline
static auto member_load_minimal(Archive const & ar, T & t, U && u, const std::uint32_t version) -> decltype(t.CEREAL_LOAD_MINIMAL_FUNCTION_NAME(ar, std::forward<U>(u), version))
{ return t.CEREAL_LOAD_MINIMAL_FUNCTION_NAME(ar, std::forward<U>(u), version); }
// ####### Other Functionality ##########################################
// for detecting inheritance from enable_shared_from_this
template <class T> inline
static auto shared_from_this(T & t) -> decltype(t.shared_from_this());
// for placement new
template <class T, class ... Args> inline
static void construct( T *& ptr, Args && ... args )
{
new (ptr) T( std::forward<Args>( args )... );
}
// for non-placement new with a default constructor
template <class T> inline
static T * construct()
{
return new T();
}
template <class T> inline
static std::false_type load_and_construct(...)
{ return std::false_type(); }
template<class T, class Archive> inline
static auto load_and_construct(Archive & ar, ::cereal::construct<T> & construct) -> decltype(T::load_and_construct(ar, construct))
{
T::load_and_construct( ar, construct );
}
template<class T, class Archive> inline
static auto load_and_construct(Archive & ar, ::cereal::construct<T> & construct, const std::uint32_t version) -> decltype(T::load_and_construct(ar, construct, version))
{
T::load_and_construct( ar, construct, version );
}
}; // end class access
// ######################################################################
// Deferred Implementation, see construct for more information
template <class T> template <class ... Args> inline
void construct<T>::operator()( Args && ... args )
{
if( itsValid )
throw Exception("Attempting to construct an already initialized object");
::cereal::access::construct( itsPtr, std::forward<Args>( args )... );
itsEnableSharedRestoreFunction();
itsValid = true;
}
} // namespace cereal
#endif // CEREAL_ACCESS_HPP_