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implement static data members

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[SVN r18157]
This commit is contained in:
Dave Abrahams
2003-04-02 12:56:37 +00:00
parent 319a5cf97c
commit 3fd9ad7a60
5 changed files with 563 additions and 72 deletions
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193
src/object/class.cpp
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@@ -41,16 +41,160 @@ instance_holder::~instance_holder()
{
}
// This is copied from typeobject.c in the Python sources. Even though
// class_metatype_object doesn't set Py_TPFLAGS_HAVE_GC, that bit gets
// filled in by the base class initialization process in
// PyType_Ready(). However, tp_is_gc is *not* copied from the base
// type, making it assume that classes are GC-able even if (like
// class_type_object) they're statically allocated.
static int
type_is_gc(PyTypeObject *python_type)
extern "C"
{
return python_type->tp_flags & Py_TPFLAGS_HEAPTYPE;
// This is copied from typeobject.c in the Python sources. Even though
// class_metatype_object doesn't set Py_TPFLAGS_HAVE_GC, that bit gets
// filled in by the base class initialization process in
// PyType_Ready(). However, tp_is_gc is *not* copied from the base
// type, making it assume that classes are GC-able even if (like
// class_type_object) they're statically allocated.
static int
type_is_gc(PyTypeObject *python_type)
{
return python_type->tp_flags & Py_TPFLAGS_HEAPTYPE;
}
// This is also copied from the Python sources. We can't implement
// static_data as a subclass property effectively without it.
typedef struct {
PyObject_HEAD
PyObject *prop_get;
PyObject *prop_set;
PyObject *prop_del;
PyObject *prop_doc;
} propertyobject;
static PyObject *
static_data_descr_get(PyObject *self, PyObject *obj, PyObject * /*type*/)
{
propertyobject *gs = (propertyobject *)self;
return PyObject_CallFunction(gs->prop_get, "()");
}
static int
static_data_descr_set(PyObject *self, PyObject *obj, PyObject *value)
{
propertyobject *gs = (propertyobject *)self;
PyObject *func, *res;
if (value == NULL)
func = gs->prop_del;
else
func = gs->prop_set;
if (func == NULL) {
PyErr_SetString(PyExc_AttributeError,
value == NULL ?
"can't delete attribute" :
"can't set attribute");
return -1;
}
if (value == NULL)
res = PyObject_CallFunction(func, "()");
else
res = PyObject_CallFunction(func, "(O)", value);
if (res == NULL)
return -1;
Py_DECREF(res);
return 0;
}
}
static PyTypeObject static_data_object = {
PyObject_HEAD_INIT(0)//&PyType_Type)
0,
"Boost.Python.class",
PyType_Type.tp_basicsize,
0,
0, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
0, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT // | Py_TPFLAGS_HAVE_GC
| Py_TPFLAGS_BASETYPE, /* tp_flags */
0, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
0, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, //&PyProperty_Type, /* tp_base */
0, /* tp_dict */
static_data_descr_get, /* tp_descr_get */
static_data_descr_set, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
0, // filled in with type_new /* tp_new */
0, // filled in with __PyObject_GC_Del /* tp_free */
(inquiry)type_is_gc, /* tp_is_gc */
};
namespace objects
{
extern "C"
{
// This declaration needed due to broken Python 2.2 headers
extern DL_IMPORT(PyTypeObject) PyProperty_Type;
}
BOOST_PYTHON_DECL PyObject* static_data()
{
if (static_data_object.tp_dict == 0)
{
static_data_object.ob_type = &PyType_Type;
static_data_object.tp_base = &PyProperty_Type;
if (PyType_Ready(&static_data_object))
return 0;
}
return upcast<PyObject>(&static_data_object);
}
}
extern "C"
{
// Ordinarily, descriptors have a certain assymetry: you can use
// them to read attributes off the class object they adorn, but
// writing the same attribute on the class object always replaces
// the descriptor in the class __dict__. In order to properly
// represent C++ static data members, we need to allow them to be
// written through the class instance. This function of the
// metaclass makes it possible.
static int
class_setattro(PyObject *obj, PyObject *name, PyObject* value)
{
// Must use "private" Python implementation detail
// _PyType_Lookup instead of PyObject_GetAttr because the
// latter will always end up calling the descr_get function on
// any descriptor it finds; we need the unadulterated
// descriptor here.
PyObject* a = _PyType_Lookup(downcast<PyTypeObject>(obj), name);
// a is a borrowed reference or 0
// If we found a static data descriptor, call it directly to
// force it to set the static data member
if (a != 0 && PyObject_IsInstance(a, objects::static_data()))
return a->ob_type->tp_descr_set(a, obj, value);
else
return PyType_Type.tp_setattro(obj, name, value);
}
}
static PyTypeObject class_metatype_object = {
@@ -72,7 +216,7 @@ static PyTypeObject class_metatype_object = {
0, /* tp_call */
0, /* tp_str */
0, /* tp_getattro */
0, /* tp_setattro */
class_setattro, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT // | Py_TPFLAGS_HAVE_GC
| Py_TPFLAGS_BASETYPE, /* tp_flags */
@@ -110,6 +254,8 @@ void instance_holder::install(PyObject* self) throw()
namespace objects
{
static int (*class_setattro_save)(PyObject *obj, PyObject *name, PyObject* value);
// Get the metatype object for all extension classes.
BOOST_PYTHON_DECL type_handle class_metatype()
{
@@ -119,6 +265,7 @@ namespace objects
class_metatype_object.tp_base = &PyType_Type;
if (PyType_Ready(&class_metatype_object))
return type_handle();
class_setattro_save = class_metatype_object.tp_setattro;
}
return type_handle(borrowed(&class_metatype_object));
}
@@ -189,6 +336,7 @@ namespace objects
inst->dict = python::incref(dict);
return 0;
}
}
@@ -254,6 +402,7 @@ namespace objects
class_type_object.tp_base = &PyBaseObject_Type;
if (PyType_Ready(&class_type_object))
return type_handle();
// class_type_object.tp_setattro = class_setattro;
}
return type_handle(borrowed(&class_type_object));
}
@@ -377,12 +526,6 @@ namespace objects
this->attr("__instance_size__") = instance_size;
}
extern "C"
{
// This declaration needed due to broken Python 2.2 headers
extern DL_IMPORT(PyTypeObject) PyProperty_Type;
}
void class_base::add_property(char const* name, object const& fget)
{
object property(
@@ -401,6 +544,24 @@ namespace objects
this->setattr(name, property);
}
void class_base::add_static_property(char const* name, object const& fget)
{
object property(
(python::detail::new_reference)
PyObject_CallFunction(static_data(), "O", fget.ptr()));
this->setattr(name, property);
}
void class_base::add_static_property(char const* name, object const& fget, object const& fset)
{
object property(
(python::detail::new_reference)
PyObject_CallFunction(static_data(), "OO", fget.ptr(), fset.ptr()));
this->setattr(name, property);
}
void class_base::setattr(char const* name, object const& x)
{
if (PyObject_SetAttrString(this->ptr(), const_cast<char*>(name), x.ptr()) < 0)