sl@0: // Copyright David Abrahams 2002.
sl@0: // Distributed under the Boost Software License, Version 1.0. (See
sl@0: // accompanying file LICENSE_1_0.txt or copy at
sl@0: // http://www.boost.org/LICENSE_1_0.txt)
sl@0: #ifndef DATA_MEMBERS_DWA2002328_HPP
sl@0: # define DATA_MEMBERS_DWA2002328_HPP
sl@0: 
sl@0: # include <boost/python/detail/prefix.hpp>
sl@0: 
sl@0: # include <boost/python/handle.hpp>
sl@0: 
sl@0: # include <boost/python/return_value_policy.hpp>
sl@0: # include <boost/python/return_by_value.hpp>
sl@0: # include <boost/python/return_internal_reference.hpp>
sl@0: # include <boost/python/make_function.hpp>
sl@0: 
sl@0: # include <boost/python/converter/builtin_converters.hpp>
sl@0: 
sl@0: # include <boost/python/detail/indirect_traits.hpp>
sl@0: # include <boost/python/detail/not_specified.hpp>
sl@0: # include <boost/python/detail/value_arg.hpp>
sl@0: 
sl@0: # include <boost/type_traits/add_const.hpp>
sl@0: # include <boost/type_traits/add_reference.hpp>
sl@0: # include <boost/type_traits/is_member_pointer.hpp>
sl@0: 
sl@0: # if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
sl@0: #  include <boost/type_traits/remove_cv.hpp>
sl@0: # endif 
sl@0: 
sl@0: # include <boost/mpl/eval_if.hpp>
sl@0: # include <boost/mpl/if.hpp>
sl@0: # include <boost/mpl/vector/vector10.hpp>
sl@0: 
sl@0: # include <boost/detail/workaround.hpp>
sl@0: 
sl@0: namespace boost { namespace python { 
sl@0: 
sl@0: //
sl@0: // This file defines the make_getter and make_setter function
sl@0: // families, which are responsible for turning pointers, references,
sl@0: // and pointers-to-data-members into callable Python objects which
sl@0: // can be used for attribute access on wrapped classes.
sl@0: //
sl@0: 
sl@0: namespace detail
sl@0: {
sl@0: 
sl@0:   // A small function object which handles the getting and setting of
sl@0:   // data members.
sl@0:   template <class Data, class Class>
sl@0:   struct member
sl@0:   {
sl@0:    public:      
sl@0:       member(Data Class::*which) : m_which(which) {}
sl@0:       
sl@0:       Data& operator()(Class& c) const
sl@0:       {
sl@0:           return c.*m_which;
sl@0:       }
sl@0: 
sl@0:       void operator()(Class& c, typename value_arg<Data>::type d) const
sl@0:       {
sl@0:           c.*m_which = d;
sl@0:       }
sl@0:    private:
sl@0:       Data Class::*m_which;
sl@0:   };
sl@0: 
sl@0:   // A small function object which handles the getting and setting of
sl@0:   // non-member objects.
sl@0:   template <class Data>
sl@0:   struct datum
sl@0:   {
sl@0:    public:      
sl@0:       datum(Data *which) : m_which(which) {}
sl@0:       
sl@0:       Data& operator()() const
sl@0:       {
sl@0:           return *m_which;
sl@0:       }
sl@0: 
sl@0:       void operator()(typename value_arg<Data>::type d) const
sl@0:       {
sl@0:           *m_which = d;
sl@0:       }
sl@0:    private:
sl@0:       Data *m_which;
sl@0:   };
sl@0:   
sl@0:   //
sl@0:   // Helper metafunction for determining the default CallPolicy to use
sl@0:   // for attribute access.  If T is a [reference to a] class type X
sl@0:   // whose conversion to python would normally produce a new copy of X
sl@0:   // in a wrapped X class instance (as opposed to types such as
sl@0:   // std::string, which are converted to native Python types, and
sl@0:   // smart pointer types which produce a wrapped class instance of the
sl@0:   // pointee type), to-python conversions will attempt to produce an
sl@0:   // object which refers to the original C++ object, rather than a
sl@0:   // copy.  See default_member_getter_policy for rationale.
sl@0:   // 
sl@0:   template <class T>
sl@0:   struct default_getter_by_ref
sl@0:       : mpl::and_<
sl@0:           mpl::bool_<
sl@0:               to_python_value<
sl@0:                   typename value_arg<T>::type
sl@0:               >::uses_registry
sl@0:           >
sl@0:         , indirect_traits::is_reference_to_class<
sl@0:               typename value_arg<T>::type
sl@0:           >
sl@0:        >
sl@0:   {
sl@0:   };
sl@0: 
sl@0:   // Metafunction computing the default CallPolicy to use for reading
sl@0:   // data members
sl@0:   //
sl@0:   // If it's a regular class type (not an object manager or other
sl@0:   // type for which we have to_python specializations, use
sl@0:   // return_internal_reference so that we can do things like
sl@0:   //    x.y.z =  1
sl@0:   // and get the right result.
sl@0:   template <class T>
sl@0:   struct default_member_getter_policy
sl@0:     : mpl::if_<
sl@0:           default_getter_by_ref<T>
sl@0:         , return_internal_reference<>
sl@0:         , return_value_policy<return_by_value>
sl@0:       >
sl@0:   {};
sl@0: 
sl@0:   // Metafunction computing the default CallPolicy to use for reading
sl@0:   // non-member data.
sl@0:   template <class T>
sl@0:   struct default_datum_getter_policy
sl@0:     : mpl::if_<
sl@0:           default_getter_by_ref<T>
sl@0:         , return_value_policy<reference_existing_object>
sl@0:         , return_value_policy<return_by_value>
sl@0:       >
sl@0:   {};
sl@0: 
sl@0:   //
sl@0:   // make_getter helper function family -- These helpers to
sl@0:   // boost::python::make_getter are used to dispatch behavior.  The
sl@0:   // third argument is a workaround for a CWPro8 partial ordering bug
sl@0:   // with pointers to data members.  It should be convertible to
sl@0:   // mpl::true_ iff the first argument is a pointer-to-member, and
sl@0:   // mpl::false_ otherwise.  The fourth argument is for compilers
sl@0:   // which don't support partial ordering at all and should always be
sl@0:   // passed 0L.
sl@0:   //
sl@0: 
sl@0: #if BOOST_WORKAROUND(__EDG_VERSION__, <= 238)
sl@0:   template <class D, class P>
sl@0:   inline object make_getter(D& d, P& p, mpl::false_, ...);
sl@0: #endif
sl@0: 
sl@0:   // Handle non-member pointers with policies
sl@0:   template <class D, class Policies>
sl@0:   inline object make_getter(D* d, Policies const& policies, mpl::false_, int)
sl@0:   {
sl@0:       return python::make_function(
sl@0:           detail::datum<D>(d), policies, mpl::vector1<D&>()
sl@0:       );
sl@0:   }
sl@0:   
sl@0:   // Handle non-member pointers without policies
sl@0:   template <class D>
sl@0:   inline object make_getter(D* d, not_specified, mpl::false_, long)
sl@0:   {
sl@0:       typedef typename default_datum_getter_policy<D>::type policies;
sl@0:       return detail::make_getter(d, policies(), mpl::false_(), 0);
sl@0:   }
sl@0: 
sl@0:   // Handle pointers-to-members with policies
sl@0:   template <class C, class D, class Policies>
sl@0:   inline object make_getter(D C::*pm, Policies const& policies, mpl::true_, int)
sl@0:   {
sl@0: #if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
sl@0:       typedef typename remove_cv<C>::type Class;
sl@0: #else
sl@0:       typedef C Class;
sl@0: #endif 
sl@0:       return python::make_function(
sl@0:           detail::member<D,Class>(pm)
sl@0:         , policies
sl@0:         , mpl::vector2<D&,Class&>()
sl@0:       );
sl@0:   }
sl@0:       
sl@0:   // Handle pointers-to-members without policies
sl@0:   template <class C, class D>
sl@0:   inline object make_getter(D C::*pm, not_specified, mpl::true_, long)
sl@0:   {
sl@0:       typedef typename default_member_getter_policy<D>::type policies;
sl@0:       return detail::make_getter(pm, policies(), mpl::true_(), 0);
sl@0:   }
sl@0: 
sl@0:   // Handle references
sl@0:   template <class D, class P>
sl@0:   inline object make_getter(D& d, P& p, mpl::false_, ...)
sl@0:   {
sl@0:       // Just dispatch to the handler for pointer types.
sl@0:       return detail::make_getter(&d, p, mpl::false_(), 0L);
sl@0:   }
sl@0: 
sl@0:   //
sl@0:   // make_setter helper function family -- These helpers to
sl@0:   // boost::python::make_setter are used to dispatch behavior.  The
sl@0:   // third argument is for compilers which don't support partial
sl@0:   // ordering at all and should always be passed 0.
sl@0:   //
sl@0: 
sl@0:   
sl@0:   // Handle non-member pointers
sl@0:   template <class D, class Policies>
sl@0:   inline object make_setter(D* p, Policies const& policies, mpl::false_, int)
sl@0:   {
sl@0:       return python::make_function(
sl@0:           detail::datum<D>(p), policies, mpl::vector2<void,D const&>()
sl@0:       );
sl@0:   }
sl@0: 
sl@0:   // Handle pointers-to-members
sl@0:   template <class C, class D, class Policies>
sl@0:   inline object make_setter(D C::*pm, Policies const& policies, mpl::true_, int)
sl@0:   {
sl@0:       return python::make_function(
sl@0:           detail::member<D,C>(pm)
sl@0:         , policies
sl@0:         , mpl::vector3<void, C&, D const&>()
sl@0:       );
sl@0:   }
sl@0: 
sl@0:   // Handle references
sl@0:   template <class D, class Policies>
sl@0:   inline object make_setter(D& x, Policies const& policies, mpl::false_, ...)
sl@0:   {
sl@0:       return detail::make_setter(&x, policies, mpl::false_(), 0L);
sl@0:   }
sl@0: }
sl@0: 
sl@0: //
sl@0: // make_getter function family -- build a callable object which
sl@0: // retrieves data through the first argument and is appropriate for
sl@0: // use as the `get' function in Python properties .  The second,
sl@0: // policies argument, is optional.  We need both D& and D const&
sl@0: // overloads in order be able to handle rvalues.
sl@0: //
sl@0: template <class D, class Policies>
sl@0: inline object make_getter(D& d, Policies const& policies)
sl@0: {
sl@0:     return detail::make_getter(d, policies, is_member_pointer<D>(), 0L);
sl@0: }
sl@0: 
sl@0: template <class D, class Policies>
sl@0: inline object make_getter(D const& d, Policies const& policies)
sl@0: {
sl@0:     return detail::make_getter(d, policies, is_member_pointer<D>(), 0L);
sl@0: }
sl@0: 
sl@0: template <class D>
sl@0: inline object make_getter(D& x)
sl@0: {
sl@0:     detail::not_specified policy;
sl@0:     return detail::make_getter(x, policy, is_member_pointer<D>(), 0L);
sl@0: }
sl@0: 
sl@0: #  if !BOOST_WORKAROUND(__EDG_VERSION__, <= 238) && !BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
sl@0: template <class D>
sl@0: inline object make_getter(D const& d)
sl@0: {
sl@0:     detail::not_specified policy;
sl@0:     return detail::make_getter(d, policy, is_member_pointer<D>(), 0L);
sl@0: }
sl@0: #  endif
sl@0: 
sl@0: //
sl@0: // make_setter function family -- build a callable object which
sl@0: // writes data through the first argument and is appropriate for
sl@0: // use as the `set' function in Python properties .  The second,
sl@0: // policies argument, is optional.  We need both D& and D const&
sl@0: // overloads in order be able to handle rvalues.
sl@0: //
sl@0: template <class D, class Policies>
sl@0: inline object make_setter(D& x, Policies const& policies)
sl@0: {
sl@0:     return detail::make_setter(x, policies, is_member_pointer<D>(), 0);
sl@0: }
sl@0: 
sl@0: template <class D, class Policies>
sl@0: inline object make_setter(D const& x, Policies const& policies)
sl@0: {
sl@0:     return detail::make_setter(x, policies, is_member_pointer<D>(), 0);
sl@0: }
sl@0: 
sl@0: template <class D>
sl@0: inline object make_setter(D& x)
sl@0: {
sl@0:     return detail::make_setter(x, default_call_policies(), is_member_pointer<D>(), 0);
sl@0: }
sl@0: 
sl@0: # if !(BOOST_WORKAROUND(BOOST_MSVC, <= 1300) || BOOST_WORKAROUND(__EDG_VERSION__, <= 238))
sl@0: template <class D>
sl@0: inline object make_setter(D const& x)
sl@0: {
sl@0:     return detail::make_setter(x, default_call_policies(), is_member_pointer<D>(), 0);
sl@0: }
sl@0: # endif
sl@0: 
sl@0: }} // namespace boost::python
sl@0: 
sl@0: #endif // DATA_MEMBERS_DWA2002328_HPP