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 ARG_FROM_PYTHON_DWA2002127_HPP
Chris@16: # define ARG_FROM_PYTHON_DWA2002127_HPP
Chris@16: 
Chris@16: # include <boost/python/detail/prefix.hpp>
Chris@16: # include <boost/python/converter/from_python.hpp>
Chris@16: # include <boost/python/detail/indirect_traits.hpp>
Chris@16: # include <boost/type_traits/transform_traits.hpp>
Chris@16: # include <boost/type_traits/cv_traits.hpp>
Chris@16: # include <boost/python/converter/rvalue_from_python_data.hpp>
Chris@16: # include <boost/mpl/eval_if.hpp>
Chris@16: # include <boost/mpl/if.hpp>
Chris@16: # include <boost/mpl/identity.hpp>
Chris@16: # include <boost/mpl/and.hpp>
Chris@16: # include <boost/mpl/or.hpp>
Chris@16: # include <boost/mpl/not.hpp>
Chris@16: # include <boost/python/converter/registry.hpp>
Chris@16: # include <boost/python/converter/registered.hpp>
Chris@16: # include <boost/python/converter/registered_pointee.hpp>
Chris@16: # include <boost/python/detail/void_ptr.hpp>
Chris@16: # include <boost/python/back_reference.hpp>
Chris@16: # include <boost/python/detail/referent_storage.hpp>
Chris@16: # include <boost/python/converter/obj_mgr_arg_from_python.hpp>
Chris@16: 
Chris@16: namespace boost { namespace python
Chris@16: {
Chris@16:   template <class T> struct arg_from_python;
Chris@16: }}
Chris@16: 
Chris@16: // This header defines Python->C++ function argument converters,
Chris@16: // parametrized on the argument type.
Chris@16: 
Chris@16: namespace boost { namespace python { namespace converter {
Chris@16: 
Chris@16: //
Chris@16: // lvalue converters
Chris@16: //
Chris@16: //   These require that an lvalue of the type U is stored somewhere in
Chris@16: //   the Python object being converted.
Chris@16: 
Chris@16: // Used when T == U*const&
Chris@16: template <class T>
Chris@16: struct pointer_cref_arg_from_python
Chris@16: {
Chris@16:     typedef T result_type;
Chris@16:     
Chris@16:     pointer_cref_arg_from_python(PyObject*);
Chris@16:     T operator()() const;
Chris@16:     bool convertible() const;
Chris@16:     
Chris@16:  private: // storage for a U*
Chris@16:     // needed because not all compilers will let us declare U* as the
Chris@16:     // return type of operator() -- we return U*const& instead
Chris@16:     typename python::detail::referent_storage<T>::type m_result;
Chris@16: };
Chris@16: 
Chris@16: // Base class for pointer and reference converters
Chris@16: struct arg_lvalue_from_python_base
Chris@16: {
Chris@16:  public: // member functions
Chris@16:     arg_lvalue_from_python_base(void* result);
Chris@16:     bool convertible() const;
Chris@16:     
Chris@16:  protected: // member functions
Chris@16:     void*const& result() const;
Chris@16:     
Chris@16:  private: // data members
Chris@16:     void* m_result;
Chris@16: };
Chris@16: 
Chris@16: // Used when T == U* 
Chris@16: template <class T>
Chris@16: struct pointer_arg_from_python : arg_lvalue_from_python_base
Chris@16: {
Chris@16:     typedef T result_type;
Chris@16:     
Chris@16:     pointer_arg_from_python(PyObject*);
Chris@16:     T operator()() const;
Chris@16: };
Chris@16: 
Chris@16: // Used when T == U& and (T != V const& or T == W volatile&)
Chris@16: template <class T>
Chris@16: struct reference_arg_from_python : arg_lvalue_from_python_base
Chris@16: {
Chris@16:     typedef T result_type;
Chris@16:     
Chris@16:     reference_arg_from_python(PyObject*);
Chris@16:     T operator()() const;
Chris@16: };
Chris@16: 
Chris@16: // ===================
Chris@16: 
Chris@16: //
Chris@16: // rvalue converters
Chris@16: //
Chris@16: //   These require only that an object of type T can be created from
Chris@16: //   the given Python object, but not that the T object exist
Chris@16: //   somewhere in storage.
Chris@16: //
Chris@16: 
Chris@16: // Used when T is a plain value (non-pointer, non-reference) type or
Chris@16: // a (non-volatile) const reference to a plain value type.
Chris@16: template <class T>
Chris@16: struct arg_rvalue_from_python
Chris@16: {
Chris@16:     typedef typename boost::add_reference<
Chris@16:         T
Chris@16:         // We can't add_const here, or it would be impossible to pass
Chris@16:         // auto_ptr<U> args from Python to C++
Chris@16:     >::type result_type;
Chris@16:     
Chris@16:     arg_rvalue_from_python(PyObject*);
Chris@16:     bool convertible() const;
Chris@16: 
Chris@16: # if BOOST_MSVC < 1301 || _MSC_FULL_VER > 13102196
Chris@16:     typename arg_rvalue_from_python<T>::
Chris@16: # endif 
Chris@16:     result_type operator()();
Chris@16:     
Chris@16:  private:
Chris@16:     rvalue_from_python_data<result_type> m_data;
Chris@16:     PyObject* m_source;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: // ==================
Chris@16: 
Chris@16: // Converts to a (PyObject*,T) bundle, for when you need a reference
Chris@16: // back to the Python object
Chris@16: template <class T>
Chris@16: struct back_reference_arg_from_python
Chris@16:     : boost::python::arg_from_python<typename T::type>
Chris@16: {
Chris@16:     typedef T result_type;
Chris@16:     
Chris@16:     back_reference_arg_from_python(PyObject*);
Chris@16:     T operator()();
Chris@16:  private:
Chris@16:     typedef boost::python::arg_from_python<typename T::type> base;
Chris@16:     PyObject* m_source;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: // ==================
Chris@16: 
Chris@16: template <class C, class T, class F>
Chris@16: struct if_2
Chris@16: {
Chris@16:     typedef typename mpl::eval_if<C, mpl::identity<T>, F>::type type;
Chris@16: };
Chris@16: 
Chris@16: // This metafunction selects the appropriate arg_from_python converter
Chris@16: // type for an argument of type T.
Chris@16: template <class T>
Chris@16: struct select_arg_from_python
Chris@16: {
Chris@16:     typedef typename if_2<
Chris@16:         is_object_manager<T>
Chris@16:       , object_manager_value_arg_from_python<T>
Chris@16:       , if_2<
Chris@16:             is_reference_to_object_manager<T>
Chris@16:           , object_manager_ref_arg_from_python<T>
Chris@16:           , if_2<
Chris@16:                 is_pointer<T>
Chris@16:               , pointer_arg_from_python<T>
Chris@16:               , if_2<
Chris@16:                     mpl::and_<
Chris@16:                         indirect_traits::is_reference_to_pointer<T>
Chris@16:                       , indirect_traits::is_reference_to_const<T>
Chris@16:                       , mpl::not_<indirect_traits::is_reference_to_volatile<T> >
Chris@16:                         >
Chris@16:                   , pointer_cref_arg_from_python<T>
Chris@16:                   , if_2<
Chris@16:                         mpl::or_<
Chris@16:                             indirect_traits::is_reference_to_non_const<T>
Chris@16:                           , indirect_traits::is_reference_to_volatile<T>
Chris@16:                         >
Chris@16:                       , reference_arg_from_python<T>
Chris@16:                       , mpl::if_<
Chris@16:                             boost::python::is_back_reference<T>
Chris@16:                           , back_reference_arg_from_python<T>
Chris@16:                           , arg_rvalue_from_python<T>
Chris@16:                         >
Chris@16:                     >
Chris@16:                 >
Chris@16:             >
Chris@16:         >
Chris@16:     >::type type;
Chris@16: };
Chris@16: 
Chris@16: // ==================
Chris@16: 
Chris@16: //
Chris@16: // implementations
Chris@16: //
Chris@16: 
Chris@16: // arg_lvalue_from_python_base
Chris@16: //
Chris@16: inline arg_lvalue_from_python_base::arg_lvalue_from_python_base(void* result)
Chris@16:     : m_result(result)
Chris@16: {
Chris@16: }
Chris@16: 
Chris@16: inline bool arg_lvalue_from_python_base::convertible() const
Chris@16: {
Chris@16:     return m_result != 0;
Chris@16: }
Chris@16: 
Chris@16: inline void*const& arg_lvalue_from_python_base::result() const
Chris@16: {
Chris@16:     return m_result;
Chris@16: }
Chris@16: 
Chris@16: // pointer_cref_arg_from_python
Chris@16: //
Chris@16: namespace detail
Chris@16: {
Chris@16:   // null_ptr_reference -- a function returning a reference to a null
Chris@16:   // pointer of type U. Needed so that extractors for T*const& can
Chris@16:   // convert Python's None.
Chris@16:   template <class T>
Chris@16:   struct null_ptr_owner
Chris@16:   {
Chris@16:       static T value;
Chris@16:   };
Chris@16:   template <class T> T null_ptr_owner<T>::value = 0;
Chris@16:   
Chris@16:   template <class U>
Chris@16:   inline U& null_ptr_reference(U&(*)())
Chris@16:   {
Chris@16:       return null_ptr_owner<U>::value;
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: template <class T>
Chris@16: inline pointer_cref_arg_from_python<T>::pointer_cref_arg_from_python(PyObject* p)
Chris@16: {
Chris@16:     // T == U*const&: store a U* in the m_result storage. Nonzero
Chris@16:     // indicates success.  If find returns nonzero, it's a pointer to
Chris@16:     // a U object.
Chris@16:     python::detail::write_void_ptr_reference(
Chris@16:         m_result.bytes
Chris@16:         , p == Py_None ? p : converter::get_lvalue_from_python(p, registered_pointee<T>::converters)
Chris@16:         , (T(*)())0);
Chris@16: }
Chris@16: 
Chris@16: template <class T>
Chris@16: inline bool pointer_cref_arg_from_python<T>::convertible() const
Chris@16: {
Chris@16:     return python::detail::void_ptr_to_reference(m_result.bytes, (T(*)())0) != 0;
Chris@16: }
Chris@16: template <class T>
Chris@16: inline T pointer_cref_arg_from_python<T>::operator()() const
Chris@16: {
Chris@16:     return (*(void**)m_result.bytes == Py_None)  // None ==> 0
Chris@16:         ? detail::null_ptr_reference((T(*)())0)
Chris@16:         // Otherwise, return a U*const& to the m_result storage.
Chris@16:         : python::detail::void_ptr_to_reference(m_result.bytes, (T(*)())0);
Chris@16: }
Chris@16: 
Chris@16: // pointer_arg_from_python
Chris@16: //
Chris@16: template <class T>
Chris@16: inline pointer_arg_from_python<T>::pointer_arg_from_python(PyObject* p)
Chris@16:     : arg_lvalue_from_python_base(
Chris@16:         p == Py_None ? p : converter::get_lvalue_from_python(p, registered_pointee<T>::converters))
Chris@16: {
Chris@16: }
Chris@16: 
Chris@16: template <class T>
Chris@16: inline T pointer_arg_from_python<T>::operator()() const
Chris@16: {
Chris@16:     return (result() == Py_None) ? 0 : T(result());
Chris@16: }
Chris@16: 
Chris@16: // reference_arg_from_python
Chris@16: //
Chris@16: template <class T>
Chris@16: inline reference_arg_from_python<T>::reference_arg_from_python(PyObject* p)
Chris@16:     : arg_lvalue_from_python_base(converter::get_lvalue_from_python(p,registered<T>::converters))
Chris@16: {
Chris@16: }
Chris@16: 
Chris@16: template <class T>
Chris@16: inline T reference_arg_from_python<T>::operator()() const
Chris@16: {
Chris@16:     return python::detail::void_ptr_to_reference(result(), (T(*)())0);
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: // arg_rvalue_from_python
Chris@16: //
Chris@16: template <class T>
Chris@16: inline arg_rvalue_from_python<T>::arg_rvalue_from_python(PyObject* obj)
Chris@16:     : m_data(converter::rvalue_from_python_stage1(obj, registered<T>::converters))
Chris@16:     , m_source(obj)
Chris@16: {
Chris@16: }
Chris@16: 
Chris@16: template <class T>
Chris@16: inline bool arg_rvalue_from_python<T>::convertible() const
Chris@16: {
Chris@16:     return m_data.stage1.convertible != 0;
Chris@16: }
Chris@16: 
Chris@16: template <class T>
Chris@16: inline typename arg_rvalue_from_python<T>::result_type
Chris@16: arg_rvalue_from_python<T>::operator()()
Chris@16: {
Chris@16:     if (m_data.stage1.construct != 0)
Chris@16:         m_data.stage1.construct(m_source, &m_data.stage1);
Chris@16:     
Chris@16:     return python::detail::void_ptr_to_reference(m_data.stage1.convertible, (result_type(*)())0);
Chris@16: }
Chris@16: 
Chris@16: // back_reference_arg_from_python
Chris@16: //
Chris@16: template <class T>
Chris@16: back_reference_arg_from_python<T>::back_reference_arg_from_python(PyObject* x)
Chris@16:   : base(x), m_source(x)
Chris@16: {
Chris@16: }
Chris@16: 
Chris@16: template <class T>
Chris@16: inline T
Chris@16: back_reference_arg_from_python<T>::operator()()
Chris@16: {
Chris@16:     return T(m_source, base::operator()());
Chris@16: }
Chris@16: 
Chris@16: }}} // namespace boost::python::converter
Chris@16: 
Chris@16: #endif // ARG_FROM_PYTHON_DWA2002127_HPP