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3rdparty/boost_1_81_0/libs/python/test/pickle3.cpp 3.15 KB
73ef4ff3   Hu Chunming   提交三方库
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  // Copyright Ralf W. Grosse-Kunstleve 2002-2004. Distributed under the Boost
  // Software License, Version 1.0. (See accompanying
  // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  
  /*
      This example shows how to make an Extension Class "pickleable".
  
      The world class below contains member data (secret_number) that
      cannot be restored by any of the constructors. Therefore it is
      necessary to provide the __getstate__/__setstate__ pair of pickle
      interface methods.
  
      The object's __dict__ is included in the result of __getstate__.
      This requires more code (compare with pickle2.cpp), but is
      unavoidable if the object's __dict__ is not always empty.
  
      For more information refer to boost/libs/python/doc/pickle.html.
   */
  
  #include <boost/python/module.hpp>
  #include <boost/python/def.hpp>
  #include <boost/python/class.hpp>
  #include <boost/python/tuple.hpp>
  #include <boost/python/dict.hpp>
  #include <boost/python/extract.hpp>
  #include <boost/python/back_reference.hpp>
  
  namespace boost_python_test {
  
    // A friendly class.
    class world
    {
      public:
        world(const std::string& _country) : secret_number(0) {
          this->country = _country;
        }
        std::string greet() const { return "Hello from " + country + "!"; }
        std::string get_country() const { return country; }
        void set_secret_number(int number) { secret_number = number; }
        int get_secret_number() const { return secret_number; }
      private:
        std::string country;
        int secret_number;
    };
  
    struct world_pickle_suite : boost::python::pickle_suite
    {
      static
      boost::python::tuple
      getinitargs(const world& w)
      {
          return boost::python::make_tuple(w.get_country());
      }
  
      static
      boost::python::tuple
      getstate(boost::python::object w_obj)
      {
          world const& w = boost::python::extract<world const&>(w_obj)();
  
          return boost::python::make_tuple(
              w_obj.attr("__dict__"),
              w.get_secret_number());
      }
  
      static
      void
      setstate(boost::python::object w_obj, boost::python::tuple state)
      {
          using namespace boost::python;
          world& w = extract<world&>(w_obj)();
  
          if (len(state) != 2)
          {
            PyErr_SetObject(PyExc_ValueError,
                            ("expected 2-item tuple in call to __setstate__; got %s"
                             % state).ptr()
                );
            throw_error_already_set();
          }
  
          // restore the object's __dict__
          dict d = extract<dict>(w_obj.attr("__dict__"))();
          d.update(state[0]);
  
          // restore the internal state of the C++ object
          long number = extract<long>(state[1]);
          if (number != 42)
              w.set_secret_number(number);
      }
  
      static bool getstate_manages_dict() { return true; }
    };
  
  }
  
  BOOST_PYTHON_MODULE(pickle3_ext)
  {
      using namespace boost_python_test;
      boost::python::class_<world>(
          "world", boost::python::init<const std::string&>())
          .def("greet", &world::greet)
          .def("get_secret_number", &world::get_secret_number)
          .def("set_secret_number", &world::set_secret_number)
          .def_pickle(world_pickle_suite())
          ;
  }