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// file : odb/cache-traits.hxx
// author : Boris Kolpackov <boris@codesynthesis.com>
// copyright : Copyright (c) 2009-2010 Code Synthesis Tools CC
// license : GNU GPL v2; see accompanying LICENSE file
#ifndef ODB_CACHE_TRAITS_HXX
#define ODB_CACHE_TRAITS_HXX
#include <odb/pre.hxx>
#include <odb/traits.hxx>
#include <odb/session.hxx>
#include <odb/pointer-traits.hxx>
namespace odb
{
// Caching traits for objects passed by pointer.
//
template <typename P, pointer_kind = pointer_traits<P>::kind>
struct pointer_cache_traits
{
typedef P pointer_type;
typedef typename pointer_traits<pointer_type>::element_type element_type;
typedef typename object_traits<element_type>::id_type id_type;
typedef session::object_position<element_type> position_type;
struct insert_guard
{
insert_guard (const position_type& pos): pos_ (pos) {}
~insert_guard () {erase (pos_);}
position_type
position () const {return pos_;}
void
release () {pos_.map_ = 0;}
private:
position_type pos_;
};
static position_type
insert (database& db, const id_type& id, const pointer_type& p)
{
if (session::has_current ())
return session::current ().insert<element_type> (db, id, p);
else
return position_type ();
}
static pointer_type
find (database& db, const id_type& id)
{
if (session::has_current ())
return session::current ().find<element_type> (db, id);
else
return pointer_type ();
}
static void
erase (database& db, const id_type& id)
{
if (session::has_current ())
session::current ().erase<element_type> (db, id);
}
static void
erase (const position_type& p)
{
if (p.map_ != 0)
session::current ().erase<element_type> (p);
}
};
// Unique pointers don't work with the object cache.
//
template <typename P>
struct pointer_cache_traits<P, pk_unique>
{
typedef P pointer_type;
typedef typename pointer_traits<pointer_type>::element_type element_type;
typedef typename object_traits<element_type>::id_type id_type;
struct position_type {};
struct insert_guard
{
insert_guard (const position_type&) {}
position_type
position () const {return position_type ();}
void
release () {}
};
static position_type
insert (database&, const id_type&, const pointer_type&)
{
return position_type ();
}
static pointer_type
find (database&, const id_type&) { return pointer_type (); }
static void
erase (database&, const id_type&) {}
static void
erase (const position_type&) {}
};
// Caching traits for objects passed by reference. Only if the object
// pointer kind is naked do we add the object to the session.
//
template <typename T,
pointer_kind =
pointer_traits<typename object_traits<T>::pointer_type>::kind>
struct reference_cache_traits
{
typedef T element_type;
typedef typename object_traits<element_type>::pointer_type pointer_type;
typedef typename object_traits<element_type>::id_type id_type;
typedef
typename pointer_cache_traits<pointer_type>::position_type
position_type;
struct insert_guard
{
insert_guard (const position_type&) {}
position_type
position () const {return position_type ();}
void
release () {}
};
static position_type
insert (database&, const id_type&, element_type&)
{
return position_type ();
}
};
template <typename T>
struct reference_cache_traits<T, pk_naked>
{
typedef T element_type;
typedef typename object_traits<element_type>::pointer_type pointer_type;
typedef typename object_traits<element_type>::id_type id_type;
typedef
typename pointer_cache_traits<pointer_type>::position_type
position_type;
typedef
typename pointer_cache_traits<pointer_type>::insert_guard
insert_guard;
static position_type
insert (database& db, const id_type& id, element_type& obj)
{
pointer_type p (&obj);
return pointer_cache_traits<pointer_type>::insert (db, id, p);
}
};
}
#include <odb/post.hxx>
#endif // ODB_CACHE_TRAITS_HXX
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