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 WITH_CUSTODIAN_AND_WARD_DWA2002131_HPP
Chris@16: # define WITH_CUSTODIAN_AND_WARD_DWA2002131_HPP
Chris@16: 
Chris@16: # include <boost/python/detail/prefix.hpp>
Chris@16: 
Chris@16: # include <boost/python/default_call_policies.hpp>
Chris@16: # include <boost/python/object/life_support.hpp>
Chris@16: # include <algorithm>
Chris@16: 
Chris@16: namespace boost { namespace python { 
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16:   template <std::size_t N>
Chris@16:   struct get_prev
Chris@16:   {
Chris@16:       template <class ArgumentPackage>
Chris@16:       static PyObject* execute(ArgumentPackage const& args, PyObject* = 0)
Chris@16:       {
Chris@16:           int const pre_n = static_cast<int>(N) - 1; // separate line is gcc-2.96 workaround
Chris@16:           return detail::get(mpl::int_<pre_n>(), args);
Chris@16:       }
Chris@16:   };
Chris@16:   template <>
Chris@16:   struct get_prev<0>
Chris@16:   {
Chris@16:       template <class ArgumentPackage>
Chris@16:       static PyObject* execute(ArgumentPackage const&, PyObject* zeroth)
Chris@16:       {
Chris@16:           return zeroth;
Chris@16:       }
Chris@16:   };
Chris@16: }
Chris@16: template <
Chris@16:     std::size_t custodian
Chris@16:   , std::size_t ward
Chris@16:   , class BasePolicy_ = default_call_policies
Chris@16: >
Chris@16: struct with_custodian_and_ward : BasePolicy_
Chris@16: {
Chris@16:     BOOST_STATIC_ASSERT(custodian != ward);
Chris@16:     BOOST_STATIC_ASSERT(custodian > 0);
Chris@16:     BOOST_STATIC_ASSERT(ward > 0);
Chris@16: 
Chris@16:     template <class ArgumentPackage>
Chris@16:     static bool precall(ArgumentPackage const& args_)
Chris@16:     {
Chris@16:         unsigned arity_ = detail::arity(args_);
Chris@16:         if (custodian > arity_ || ward > arity_)
Chris@16:         {
Chris@16:             PyErr_SetString(
Chris@16:                 PyExc_IndexError
Chris@16:               , "boost::python::with_custodian_and_ward: argument index out of range"
Chris@16:             );
Chris@16:             return false;
Chris@16:         }
Chris@16: 
Chris@16:         PyObject* patient = detail::get_prev<ward>::execute(args_);
Chris@16:         PyObject* nurse = detail::get_prev<custodian>::execute(args_);
Chris@16: 
Chris@16:         PyObject* life_support = python::objects::make_nurse_and_patient(nurse, patient);
Chris@16:         if (life_support == 0)
Chris@16:             return false;
Chris@16:     
Chris@16:         bool result = BasePolicy_::precall(args_);
Chris@16: 
Chris@16:         if (!result) {
Chris@16:             Py_DECREF(life_support);
Chris@16:         }
Chris@16:     
Chris@16:         return result;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template <std::size_t custodian, std::size_t ward, class BasePolicy_ = default_call_policies>
Chris@16: struct with_custodian_and_ward_postcall : BasePolicy_
Chris@16: {
Chris@16:     BOOST_STATIC_ASSERT(custodian != ward);
Chris@16:     
Chris@16:     template <class ArgumentPackage>
Chris@16:     static PyObject* postcall(ArgumentPackage const& args_, PyObject* result)
Chris@16:     {
Chris@16:         std::size_t arity_ = detail::arity(args_);
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
Chris@16:         if ( custodian > arity_ || ward > arity_ )
Chris@16: #else
Chris@16:         // check if either custodian or ward exceeds the arity
Chris@16:         // (this weird formulation avoids "always false" warnings
Chris@16:         // for arity_ = 0)
Chris@16:         if ( (std::max)(custodian, ward) > arity_ )
Chris@16: #endif
Chris@16:         {
Chris@16:             PyErr_SetString(
Chris@16:                 PyExc_IndexError
Chris@16:               , "boost::python::with_custodian_and_ward_postcall: argument index out of range"
Chris@16:             );
Chris@16:             return 0;
Chris@16:         }
Chris@16:         
Chris@16:         PyObject* patient = detail::get_prev<ward>::execute(args_, result);
Chris@16:         PyObject* nurse = detail::get_prev<custodian>::execute(args_, result);
Chris@16: 
Chris@16:         if (nurse == 0) return 0;
Chris@16:     
Chris@16:         result = BasePolicy_::postcall(args_, result);
Chris@16:         if (result == 0)
Chris@16:             return 0;
Chris@16:             
Chris@16:         if (python::objects::make_nurse_and_patient(nurse, patient) == 0)
Chris@16:         {
Chris@16:             Py_XDECREF(result);
Chris@16:             return 0;
Chris@16:         }
Chris@16:         return result;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: }} // namespace boost::python
Chris@16: 
Chris@16: #endif // WITH_CUSTODIAN_AND_WARD_DWA2002131_HPP