function.cpp

C++的一个好库。。。现在很流行

      "rrshift__",
      "rshift__",
      "rsub__",
      "rtruediv__",
      "rxor__",
      "sub__",
      "truediv__", 
      "xor__"
  };

  struct less_cstring
  {
      bool operator()(char const* x, char const* y) const
      {
          return BOOST_CSTD_::strcmp(x,y) < 0;
      }
  };
  
  inline bool is_binary_operator(char const* name)
  {
      return name[0] == '_'
          && name[1] == '_'
          && std::binary_search(
              &binary_operator_names[0]
              , binary_operator_names + sizeof(binary_operator_names)/sizeof(*binary_operator_names)
              , name + 2
              , less_cstring()
              );
  }

  // Something for the end of the chain of binary operators
  PyObject* not_implemented(PyObject*, PyObject*)
  {
      Py_INCREF(Py_NotImplemented);
      return Py_NotImplemented;
  }
  
  handle<function> not_implemented_function()
  {
      
      static object keeper(
          function_object(
              py_function(&not_implemented, mpl::vector1<void>(), 2)
            , python::detail::keyword_range())
          );
      return handle<function>(borrowed(downcast<function>(keeper.ptr())));
  }
}

void function::add_to_namespace(
    object const& name_space, char const* name_, object const& attribute)
{
    str const name(name_);
    PyObject* const ns = name_space.ptr();
    
    if (attribute.ptr()->ob_type == &function_type)
    {
        function* new_func = downcast<function>(attribute.ptr());
        PyObject* dict = 0;
        
        if (PyClass_Check(ns))
            dict = ((PyClassObject*)ns)->cl_dict;
        else if (PyType_Check(ns))
            dict = ((PyTypeObject*)ns)->tp_dict;
        else    
            dict = PyObject_GetAttrString(ns, "__dict__");

        if (dict == 0)
            throw_error_already_set();

        handle<> existing(allow_null(::PyObject_GetItem(dict, name.ptr())));
        
        if (existing)
        {
            if (existing->ob_type == &function_type)
            {
                new_func->add_overload(
                    handle<function>(
                        borrowed(
                            downcast<function>(existing.get())
                        )
                    )
                );
            }
            else if (existing->ob_type == &PyStaticMethod_Type)
            {
                char const* name_space_name = extract<char const*>(name_space.attr("__name__"));
                
                ::PyErr_Format(
                    PyExc_RuntimeError
                    , "Boost.Python - All overloads must be exported "
                      "before calling \'class_<...>(\"%s\").staticmethod(\"%s\")\'"
                    , name_space_name
                    , name_
                    );
                throw_error_already_set();
            }
        }
        else if (is_binary_operator(name_))
        {
            // Binary operators need an additional overload which
            // returns NotImplemented, so that Python will try the
            // __rxxx__ functions on the other operand. We add this
            // when no overloads for the operator already exist.
            new_func->add_overload(not_implemented_function());
        }

        // A function is named the first time it is added to a namespace.
        if (new_func->name().ptr() == Py_None)
            new_func->m_name = name;

        handle<> name_space_name(
            allow_null(::PyObject_GetAttrString(name_space.ptr(), "__name__")));
        
        if (name_space_name)
            new_func->m_namespace = object(name_space_name);
    }

    // The PyObject_GetAttrString() or PyObject_GetItem calls above may
    // have left an active error
    PyErr_Clear();
    if (PyObject_SetAttr(ns, name.ptr(), attribute.ptr()) < 0)
        throw_error_already_set();
}

void function::add_to_namespace(
    object const& name_space, char const* name_, object const& attribute, char const* doc)
{
    add_to_namespace(name_space, name_, attribute);
    if (doc != 0)
    {
        // Accumulate documentation
        object mutable_attribute(attribute);
        
        if (
            PyObject_HasAttrString(mutable_attribute.ptr(), "__doc__")
            && mutable_attribute.attr("__doc__"))
        {
            mutable_attribute.attr("__doc__") += "\n\n";
            mutable_attribute.attr("__doc__") += doc;
        }
        else
            mutable_attribute.attr("__doc__") = doc;
    }
}

BOOST_PYTHON_DECL void add_to_namespace(
    object const& name_space, char const* name, object const& attribute)
{
    function::add_to_namespace(name_space, name, attribute);
}

BOOST_PYTHON_DECL void add_to_namespace(
    object const& name_space, char const* name, object const& attribute, char const* doc)
{
    function::add_to_namespace(name_space, name, attribute, doc);    
}


namespace
{
  struct bind_return
  {
      bind_return(PyObject*& result, function const* f, PyObject* args, PyObject* keywords)
          : m_result(result)
            , m_f(f)
            , m_args(args)
            , m_keywords(keywords)
      {}

      void operator()() const
      {
          m_result = m_f->call(m_args, m_keywords);
      }
      
   private:
      PyObject*& m_result;
      function const* m_f;
      PyObject* m_args;
      PyObject* m_keywords;
  };
}

extern "C"
{
    // Stolen from Python's funcobject.c
    static PyObject *
    function_descr_get(PyObject *func, PyObject *obj, PyObject *type_)
    {
        if (obj == Py_None)
            obj = NULL;
        return PyMethod_New(func, obj, type_);
    }

    static void
    function_dealloc(PyObject* p)
    {
        delete static_cast<function*>(p);
    }

    static PyObject *
    function_call(PyObject *func, PyObject *args, PyObject *kw)
    {
        PyObject* result = 0;
        handle_exception(bind_return(result, static_cast<function*>(func), args, kw));
        return result;
    }

    //
    // Here we're using the function's tp_getset rather than its
    // tp_members to set up __doc__ and __name__, because tp_members
    // really depends on having a POD object type (it relies on
    // offsets). It might make sense to reformulate function as a POD
    // at some point, but this is much more expedient.
    //
    static PyObject* function_get_doc(PyObject* op, void*)
    {
        function* f = downcast<function>(op);
        return python::incref(f->doc().ptr());
    }
    
    static int function_set_doc(PyObject* op, PyObject* doc, void*)
    {
        function* f = downcast<function>(op);
        f->doc(doc ? object(python::detail::borrowed_reference(doc)) : object());
        return 0;
    }
    
    static PyObject* function_get_name(PyObject* op, void*)
    {
        function* f = downcast<function>(op);
        if (f->name().ptr() == Py_None)
            return PyString_InternFromString("<unnamed Boost.Python function>");
        else
            return python::incref(f->name().ptr());
    }

    // We add a dummy __class__ attribute in order to fool PyDoc into
    // treating these as built-in functions and scanning their
    // documentation
    static PyObject* function_get_class(PyObject* op, void*)
    {
        return python::incref(upcast<PyObject>(&PyCFunction_Type));
    }
}
    
static PyGetSetDef function_getsetlist[] = {
    {"__name__", (getter)function_get_name, 0 },
    {"func_name", (getter)function_get_name, 0 },
    {"__class__", (getter)function_get_class, 0 },    // see note above
    {"__doc__", (getter)function_get_doc, (setter)function_set_doc},
    {"func_doc", (getter)function_get_doc, (setter)function_set_doc},
    {NULL} /* Sentinel */
};

PyTypeObject function_type = {
    PyObject_HEAD_INIT(0)
    0,
    "Boost.Python.function",
    sizeof(function),
    0,
    (destructor)function_dealloc,               /* tp_dealloc */
    0,                                  /* tp_print */
    0,                                  /* tp_getattr */
    0,                                  /* tp_setattr */
    0,                                  /* tp_compare */
    0, //(reprfunc)func_repr,                   /* tp_repr */
    0,                                  /* tp_as_number */
    0,                                  /* tp_as_sequence */
    0,                                  /* tp_as_mapping */
    0,                                  /* tp_hash */
    function_call,                              /* tp_call */
    0,                                  /* tp_str */
    0, // PyObject_GenericGetAttr,            /* tp_getattro */
    0, // PyObject_GenericSetAttr,            /* tp_setattro */
    0,                                  /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT /* | Py_TPFLAGS_HAVE_GC */,/* tp_flags */
    0,                                  /* tp_doc */
    0, // (traverseproc)func_traverse,          /* tp_traverse */
    0,                                  /* tp_clear */
    0,                                  /* tp_richcompare */
    0, //offsetof(PyFunctionObject, func_weakreflist), /* tp_weaklistoffset */
    0,                                  /* tp_iter */
    0,                                  /* tp_iternext */
    0,                                  /* tp_methods */
    0, // func_memberlist,              /* tp_members */
    function_getsetlist,                /* tp_getset */
    0,                                  /* tp_base */
    0,                                  /* tp_dict */
    function_descr_get,                 /* tp_descr_get */
    0,                                  /* tp_descr_set */
    0, //offsetof(PyFunctionObject, func_dict),      /* tp_dictoffset */
    0,                                      /* tp_init */
    0,                                      /* tp_alloc */
    0,
    0                                       /* tp_new */
};

object function_object(
    py_function const& f
    , python::detail::keyword_range const& keywords)
{
    return python::object(
        python::detail::new_non_null_reference(
            new function(
                f, keywords.first, keywords.second - keywords.first)));
}

object function_object(py_function const& f)
{
    return function_object(f, python::detail::keyword_range());
}


handle<> function_handle_impl(py_function const& f)
{
    return python::handle<>(
        allow_null(
            new function(f, 0, 0)));
}

} // namespace objects

namespace detail
{
  object BOOST_PYTHON_DECL make_raw_function(objects::py_function f)
  {
      static keyword k;
    
      return objects::function_object(
          f
          , keyword_range(&k,&k));
  }
  void BOOST_PYTHON_DECL pure_virtual_called()
  {
      PyErr_SetString(PyExc_RuntimeError, "Pure virtual function called");
      throw_error_already_set();
  }
}

}} // namespace boost::python