Chris@16: // Copyright David Abrahams 2002.
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: #ifndef DATA_MEMBERS_DWA2002328_HPP
Chris@16: # define DATA_MEMBERS_DWA2002328_HPP
Chris@16: 
Chris@16: # include <boost/python/detail/prefix.hpp>
Chris@16: 
Chris@16: # include <boost/python/handle.hpp>
Chris@16: 
Chris@16: # include <boost/python/return_value_policy.hpp>
Chris@16: # include <boost/python/return_by_value.hpp>
Chris@16: # include <boost/python/return_internal_reference.hpp>
Chris@16: # include <boost/python/make_function.hpp>
Chris@16: 
Chris@16: # include <boost/python/converter/builtin_converters.hpp>
Chris@16: 
Chris@16: # include <boost/python/detail/indirect_traits.hpp>
Chris@16: # include <boost/python/detail/not_specified.hpp>
Chris@16: # include <boost/python/detail/value_arg.hpp>
Chris@16: 
Chris@16: # include <boost/type_traits/add_const.hpp>
Chris@16: # include <boost/type_traits/add_reference.hpp>
Chris@16: # include <boost/type_traits/is_member_pointer.hpp>
Chris@16: 
Chris@16: # if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
Chris@16: #  include <boost/type_traits/remove_cv.hpp>
Chris@16: # endif 
Chris@16: 
Chris@16: # include <boost/mpl/eval_if.hpp>
Chris@16: # include <boost/mpl/if.hpp>
Chris@16: # include <boost/mpl/vector/vector10.hpp>
Chris@16: 
Chris@16: # include <boost/detail/workaround.hpp>
Chris@16: 
Chris@16: namespace boost { namespace python { 
Chris@16: 
Chris@16: //
Chris@16: // This file defines the make_getter and make_setter function
Chris@16: // families, which are responsible for turning pointers, references,
Chris@16: // and pointers-to-data-members into callable Python objects which
Chris@16: // can be used for attribute access on wrapped classes.
Chris@16: //
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@16:   // A small function object which handles the getting and setting of
Chris@16:   // data members.
Chris@16:   template <class Data, class Class>
Chris@16:   struct member
Chris@16:   {
Chris@16:    public:      
Chris@16:       member(Data Class::*which) : m_which(which) {}
Chris@16:       
Chris@16:       Data& operator()(Class& c) const
Chris@16:       {
Chris@16:           return c.*m_which;
Chris@16:       }
Chris@16: 
Chris@16:       void operator()(Class& c, typename value_arg<Data>::type d) const
Chris@16:       {
Chris@16:           c.*m_which = d;
Chris@16:       }
Chris@16:    private:
Chris@16:       Data Class::*m_which;
Chris@16:   };
Chris@16: 
Chris@16:   // A small function object which handles the getting and setting of
Chris@16:   // non-member objects.
Chris@16:   template <class Data>
Chris@16:   struct datum
Chris@16:   {
Chris@16:    public:      
Chris@16:       datum(Data *which) : m_which(which) {}
Chris@16:       
Chris@16:       Data& operator()() const
Chris@16:       {
Chris@16:           return *m_which;
Chris@16:       }
Chris@16: 
Chris@16:       void operator()(typename value_arg<Data>::type d) const
Chris@16:       {
Chris@16:           *m_which = d;
Chris@16:       }
Chris@16:    private:
Chris@16:       Data *m_which;
Chris@16:   };
Chris@16:   
Chris@16:   //
Chris@16:   // Helper metafunction for determining the default CallPolicy to use
Chris@16:   // for attribute access.  If T is a [reference to a] class type X
Chris@16:   // whose conversion to python would normally produce a new copy of X
Chris@16:   // in a wrapped X class instance (as opposed to types such as
Chris@16:   // std::string, which are converted to native Python types, and
Chris@16:   // smart pointer types which produce a wrapped class instance of the
Chris@16:   // pointee type), to-python conversions will attempt to produce an
Chris@16:   // object which refers to the original C++ object, rather than a
Chris@16:   // copy.  See default_member_getter_policy for rationale.
Chris@16:   // 
Chris@16:   template <class T>
Chris@16:   struct default_getter_by_ref
Chris@16:       : mpl::and_<
Chris@16:           mpl::bool_<
Chris@16:               to_python_value<
Chris@16:                   typename value_arg<T>::type
Chris@16:               >::uses_registry
Chris@16:           >
Chris@16:         , indirect_traits::is_reference_to_class<
Chris@16:               typename value_arg<T>::type
Chris@16:           >
Chris@16:        >
Chris@16:   {
Chris@16:   };
Chris@16: 
Chris@16:   // Metafunction computing the default CallPolicy to use for reading
Chris@16:   // data members
Chris@16:   //
Chris@16:   // If it's a regular class type (not an object manager or other
Chris@16:   // type for which we have to_python specializations, use
Chris@16:   // return_internal_reference so that we can do things like
Chris@16:   //    x.y.z =  1
Chris@16:   // and get the right result.
Chris@16:   template <class T>
Chris@16:   struct default_member_getter_policy
Chris@16:     : mpl::if_<
Chris@16:           default_getter_by_ref<T>
Chris@16:         , return_internal_reference<>
Chris@16:         , return_value_policy<return_by_value>
Chris@16:       >
Chris@16:   {};
Chris@16: 
Chris@16:   // Metafunction computing the default CallPolicy to use for reading
Chris@16:   // non-member data.
Chris@16:   template <class T>
Chris@16:   struct default_datum_getter_policy
Chris@16:     : mpl::if_<
Chris@16:           default_getter_by_ref<T>
Chris@16:         , return_value_policy<reference_existing_object>
Chris@16:         , return_value_policy<return_by_value>
Chris@16:       >
Chris@16:   {};
Chris@16: 
Chris@16:   //
Chris@16:   // make_getter helper function family -- These helpers to
Chris@16:   // boost::python::make_getter are used to dispatch behavior.  The
Chris@16:   // third argument is a workaround for a CWPro8 partial ordering bug
Chris@16:   // with pointers to data members.  It should be convertible to
Chris@16:   // mpl::true_ iff the first argument is a pointer-to-member, and
Chris@16:   // mpl::false_ otherwise.  The fourth argument is for compilers
Chris@16:   // which don't support partial ordering at all and should always be
Chris@16:   // passed 0L.
Chris@16:   //
Chris@16: 
Chris@16: #if BOOST_WORKAROUND(__EDG_VERSION__, <= 238)
Chris@16:   template <class D, class P>
Chris@16:   inline object make_getter(D& d, P& p, mpl::false_, ...);
Chris@16: #endif
Chris@16: 
Chris@16:   // Handle non-member pointers with policies
Chris@16:   template <class D, class Policies>
Chris@16:   inline object make_getter(D* d, Policies const& policies, mpl::false_, int)
Chris@16:   {
Chris@16:       return python::make_function(
Chris@16:           detail::datum<D>(d), policies, mpl::vector1<D&>()
Chris@16:       );
Chris@16:   }
Chris@16:   
Chris@16:   // Handle non-member pointers without policies
Chris@16:   template <class D>
Chris@16:   inline object make_getter(D* d, not_specified, mpl::false_, long)
Chris@16:   {
Chris@16:       typedef typename default_datum_getter_policy<D>::type policies;
Chris@16:       return detail::make_getter(d, policies(), mpl::false_(), 0);
Chris@16:   }
Chris@16: 
Chris@16:   // Handle pointers-to-members with policies
Chris@16:   template <class C, class D, class Policies>
Chris@16:   inline object make_getter(D C::*pm, Policies const& policies, mpl::true_, int)
Chris@16:   {
Chris@16: #if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
Chris@16:       typedef typename remove_cv<C>::type Class;
Chris@16: #else
Chris@16:       typedef C Class;
Chris@16: #endif 
Chris@16:       return python::make_function(
Chris@16:           detail::member<D,Class>(pm)
Chris@16:         , policies
Chris@16:         , mpl::vector2<D&,Class&>()
Chris@16:       );
Chris@16:   }
Chris@16:       
Chris@16:   // Handle pointers-to-members without policies
Chris@16:   template <class C, class D>
Chris@16:   inline object make_getter(D C::*pm, not_specified, mpl::true_, long)
Chris@16:   {
Chris@16:       typedef typename default_member_getter_policy<D>::type policies;
Chris@16:       return detail::make_getter(pm, policies(), mpl::true_(), 0);
Chris@16:   }
Chris@16: 
Chris@16:   // Handle references
Chris@16:   template <class D, class P>
Chris@16:   inline object make_getter(D& d, P& p, mpl::false_, ...)
Chris@16:   {
Chris@16:       // Just dispatch to the handler for pointer types.
Chris@16:       return detail::make_getter(&d, p, mpl::false_(), 0L);
Chris@16:   }
Chris@16: 
Chris@16:   //
Chris@16:   // make_setter helper function family -- These helpers to
Chris@16:   // boost::python::make_setter are used to dispatch behavior.  The
Chris@16:   // third argument is for compilers which don't support partial
Chris@16:   // ordering at all and should always be passed 0.
Chris@16:   //
Chris@16: 
Chris@16:   
Chris@16:   // Handle non-member pointers
Chris@16:   template <class D, class Policies>
Chris@16:   inline object make_setter(D* p, Policies const& policies, mpl::false_, int)
Chris@16:   {
Chris@16:       return python::make_function(
Chris@16:           detail::datum<D>(p), policies, mpl::vector2<void,D const&>()
Chris@16:       );
Chris@16:   }
Chris@16: 
Chris@16:   // Handle pointers-to-members
Chris@16:   template <class C, class D, class Policies>
Chris@16:   inline object make_setter(D C::*pm, Policies const& policies, mpl::true_, int)
Chris@16:   {
Chris@16:       return python::make_function(
Chris@16:           detail::member<D,C>(pm)
Chris@16:         , policies
Chris@16:         , mpl::vector3<void, C&, D const&>()
Chris@16:       );
Chris@16:   }
Chris@16: 
Chris@16:   // Handle references
Chris@16:   template <class D, class Policies>
Chris@16:   inline object make_setter(D& x, Policies const& policies, mpl::false_, ...)
Chris@16:   {
Chris@16:       return detail::make_setter(&x, policies, mpl::false_(), 0L);
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: //
Chris@16: // make_getter function family -- build a callable object which
Chris@16: // retrieves data through the first argument and is appropriate for
Chris@16: // use as the `get' function in Python properties .  The second,
Chris@16: // policies argument, is optional.  We need both D& and D const&
Chris@16: // overloads in order be able to handle rvalues.
Chris@16: //
Chris@16: template <class D, class Policies>
Chris@16: inline object make_getter(D& d, Policies const& policies)
Chris@16: {
Chris@16:     return detail::make_getter(d, policies, is_member_pointer<D>(), 0L);
Chris@16: }
Chris@16: 
Chris@16: template <class D, class Policies>
Chris@16: inline object make_getter(D const& d, Policies const& policies)
Chris@16: {
Chris@16:     return detail::make_getter(d, policies, is_member_pointer<D>(), 0L);
Chris@16: }
Chris@16: 
Chris@16: template <class D>
Chris@16: inline object make_getter(D& x)
Chris@16: {
Chris@16:     detail::not_specified policy
Chris@16:         = detail::not_specified(); // suppress a SunPro warning
Chris@16:     return detail::make_getter(x, policy, is_member_pointer<D>(), 0L);
Chris@16: }
Chris@16: 
Chris@16: #  if !BOOST_WORKAROUND(__EDG_VERSION__, <= 238) && !BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
Chris@16: template <class D>
Chris@16: inline object make_getter(D const& d)
Chris@16: {
Chris@16:     detail::not_specified policy
Chris@16:         = detail::not_specified(); // Suppress a SunPro warning
Chris@16:     return detail::make_getter(d, policy, is_member_pointer<D>(), 0L);
Chris@16: }
Chris@16: #  endif
Chris@16: 
Chris@16: //
Chris@16: // make_setter function family -- build a callable object which
Chris@16: // writes data through the first argument and is appropriate for
Chris@16: // use as the `set' function in Python properties .  The second,
Chris@16: // policies argument, is optional.  We need both D& and D const&
Chris@16: // overloads in order be able to handle rvalues.
Chris@16: //
Chris@16: template <class D, class Policies>
Chris@16: inline object make_setter(D& x, Policies const& policies)
Chris@16: {
Chris@16:     return detail::make_setter(x, policies, is_member_pointer<D>(), 0);
Chris@16: }
Chris@16: 
Chris@16: template <class D, class Policies>
Chris@16: inline object make_setter(D const& x, Policies const& policies)
Chris@16: {
Chris@16:     return detail::make_setter(x, policies, is_member_pointer<D>(), 0);
Chris@16: }
Chris@16: 
Chris@16: template <class D>
Chris@16: inline object make_setter(D& x)
Chris@16: {
Chris@16:     return detail::make_setter(x, default_call_policies(), is_member_pointer<D>(), 0);
Chris@16: }
Chris@16: 
Chris@16: # if !(BOOST_WORKAROUND(BOOST_MSVC, <= 1300) || BOOST_WORKAROUND(__EDG_VERSION__, <= 238))
Chris@16: template <class D>
Chris@16: inline object make_setter(D const& x)
Chris@16: {
Chris@16:     return detail::make_setter(x, default_call_policies(), is_member_pointer<D>(), 0);
Chris@16: }
Chris@16: # endif
Chris@16: 
Chris@16: }} // namespace boost::python
Chris@16: 
Chris@16: #endif // DATA_MEMBERS_DWA2002328_HPP