ceph/src/boost/libs/python/include/boost/python/converter/implicit.hpp

   1 // Copyright David Abrahams 2002.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5 #ifndef IMPLICIT_DWA2002326_HPP
   6 # define IMPLICIT_DWA2002326_HPP
   7
   8 # include <boost/python/converter/rvalue_from_python_data.hpp>
   9 # include <boost/python/converter/registrations.hpp>
  10 # include <boost/python/converter/registered.hpp>
  11
  12 # include <boost/python/extract.hpp>
  13
  14 namespace boost { namespace python { namespace converter {
  15
  16 template <class Source, class Target>
  17 struct implicit
  18 {
  19     static void* convertible(PyObject* obj)
  20     {
  21         // Find a converter which can produce a Source instance from
  22         // obj. The user has told us that Source can be converted to
  23         // Target, and instantiating construct() below, ensures that
  24         // at compile-time.
  25         return implicit_rvalue_convertible_from_python(obj, registered<Source>::converters)
  26             ? obj : 0;
  27     }
  28
  29     static void construct(PyObject* obj, rvalue_from_python_stage1_data* data)
  30     {
  31         void* storage = ((rvalue_from_python_storage<Target>*)data)->storage.bytes;
  32
  33         arg_from_python<Source> get_source(obj);
  34         bool convertible = get_source.convertible();
  35         BOOST_VERIFY(convertible);
  36
  37         new (storage) Target(get_source());
  38
  39         // record successful construction
  40         data->convertible = storage;
  41     }
  42 };
  43
  44 }}} // namespace boost::python::converter
  45
  46 #endif // IMPLICIT_DWA2002326_HPP