python/src/object/class.cpp at python313 · boostorg/python · GitHub

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// Copyright David Abrahams 2001.

// 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)

#include <boost/python/detail/prefix.hpp>

#include <boost/mpl/lambda.hpp> // #including this first is an intel6 workaround

#include <boost/cstdint.hpp>

#include <boost/python/object/class.hpp>

#include <boost/python/object/instance.hpp>

#include <boost/python/object/class_detail.hpp>

#include <boost/python/scope.hpp>

#include <boost/python/converter/registry.hpp>

#include <boost/python/object/find_instance.hpp>

#include <boost/python/object/pickle_support.hpp>

#include <boost/python/detail/map_entry.hpp>

#include <boost/python/object.hpp>

#include <boost/python/object_protocol.hpp>

#include <boost/detail/binary_search.hpp>

#include <boost/python/self.hpp>

#include <boost/python/dict.hpp>

#include <boost/python/str.hpp>

#include <boost/python/ssize_t.hpp>

#include <functional>

#include <vector>

#include <cstddef>

#include <new>

#include <structmember.h>

namespace boost { namespace python {

# ifdef BOOST_PYTHON_SELF_IS_CLASS

namespace self_ns

{

self_t self;

}

# endif

instance_holder::instance_holder()

: m_next(0)

{

}

instance_holder::~instance_holder()

{

}

extern "C"

{

// 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;

int getter_doc;

} propertyobject;

// Copied from Python source and removed the part for setting docstring,

// since we don't have a setter for __doc__ and trying to set it will

// cause the init fail.

static int property_init(PyObject *self, PyObject *args, PyObject *kwds)

{

PyObject *get = NULL, *set = NULL, *del = NULL, *doc = NULL;

static const char *kwlist[] = {"fget", "fset", "fdel", "doc", 0};

propertyobject *prop = (propertyobject *)self;

if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OOOO:property",

const_cast<char **>(kwlist), &get, &set, &del, &doc))

return -1;

if (get == Py_None)

get = NULL;

if (set == Py_None)

set = NULL;

if (del == Py_None)

del = NULL;

Py_XINCREF(get);

Py_XINCREF(set);

Py_XINCREF(del);

Py_XINCREF(doc);

prop->prop_get = get;

prop->prop_set = set;

prop->prop_del = del;

prop->prop_doc = doc;

prop->getter_doc = 0;

return 0;

}

static PyObject *

static_data_descr_get(PyObject *self, PyObject * /*obj*/, PyObject * /*type*/)

{

propertyobject *gs = (propertyobject *)self;

return PyObject_CallFunction(gs->prop_get, const_cast<char*>("()"));

}

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, const_cast<char*>("()"));

else

res = PyObject_CallFunction(func, const_cast<char*>("(O)"), value);

if (res == NULL)

return -1;

Py_DECREF(res);

return 0;

}

static PyTypeObject static_data_object = {

PyVarObject_HEAD_INIT(NULL, 0)

const_cast<char*>("Boost.Python.StaticProperty"),

sizeof(propertyobject),

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 */

property_init, /* tp_init */

0, /* tp_alloc */

0, // filled in with type_new /* tp_new */

0, // filled in with __PyObject_GC_Del /* tp_free */

0, /* tp_is_gc */

0, /* tp_bases */

0, /* tp_mro */

0, /* tp_cache */

0, /* tp_subclasses */

0, /* tp_weaklist */

#if PYTHON_API_VERSION >= 1012

0 /* tp_del */

#endif

};

namespace objects

{

#if PY_VERSION_HEX < 0x03000000

// XXX Not sure why this run into compiling error in Python 3

extern "C"

{

// This declaration needed due to broken Python 2.2 headers

extern DL_IMPORT(PyTypeObject) PyProperty_Type;

}

#endif

BOOST_PYTHON_DECL PyObject* static_data()

{

if (static_data_object.tp_dict == 0)

{

Py_SET_TYPE(&static_data_object, &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 Py_TYPE(a)->tp_descr_set(a, obj, value);

else

return PyType_Type.tp_setattro(obj, name, value);

}

static PyTypeObject class_metatype_object = {

PyVarObject_HEAD_INIT(NULL, 0)

const_cast<char*>("Boost.Python.class"),

PyType_Type.tp_basicsize,

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 */

class_setattro, /* 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, //&PyType_Type, /* tp_base */

0, /* tp_dict */

0, /* tp_descr_get */

0, /* 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 */

0, /* tp_bases */

0, /* tp_mro */

0, /* tp_cache */

0, /* tp_subclasses */

0, /* tp_weaklist */

#if PYTHON_API_VERSION >= 1012

0 /* tp_del */

#endif

};

// Install the instance data for a C++ object into a Python instance

// object.

void instance_holder::install(PyObject* self) throw()

{

assert(PyType_IsSubtype(Py_TYPE(Py_TYPE(self)), &class_metatype_object));

m_next = ((objects::instance<>*)self)->objects;

((objects::instance<>*)self)->objects = this;

}

namespace objects

{

// Get the metatype object for all extension classes.

BOOST_PYTHON_DECL type_handle class_metatype()

{

if (class_metatype_object.tp_dict == 0)

{

Py_SET_TYPE(&class_metatype_object, &PyType_Type);

class_metatype_object.tp_base = &PyType_Type;

if (PyType_Ready(&class_metatype_object))

return type_handle();

}

return type_handle(borrowed(&class_metatype_object));

}

extern "C"

{

static void instance_dealloc(PyObject* inst)

{

instance<>* kill_me = (instance<>*)inst;

for (instance_holder* p = kill_me->objects, *next; p != 0; p = next)

{

next = p->next();

void* q = dynamic_cast<void*>(p);

p->~instance_holder();

instance_holder::deallocate(inst, q);

}

// Python 2.2.1 won't add weak references automatically when

// tp_itemsize > 0, so we need to manage that

// ourselves. Accordingly, we also have to clean up the

// weakrefs ourselves.

if (kill_me->weakrefs != NULL)

PyObject_ClearWeakRefs(inst);

Py_XDECREF(kill_me->dict);

Py_TYPE(inst)->tp_free(inst);

}

static PyObject *

instance_new(PyTypeObject* type_, PyObject* /*args*/, PyObject* /*kw*/)

{

// Attempt to find the __instance_size__ attribute. If not present, no problem.

PyObject* d = type_->tp_dict;

PyObject* instance_size_obj = PyObject_GetAttrString(d, const_cast<char*>("__instance_size__"));

ssize_t instance_size = instance_size_obj ?

#if PY_VERSION_HEX >= 0x03000000

PyLong_AsSsize_t(instance_size_obj) : 0;

#else

PyInt_AsLong(instance_size_obj) : 0;

#endif

if (instance_size < 0)

instance_size = 0;

PyErr_Clear(); // Clear any errors that may have occurred.

instance<>* result = (instance<>*)type_->tp_alloc(type_, instance_size);

if (result)

{

// Guido says we can use ob_size for any purpose we

// like, so we'll store the total size of the object

// there. A negative number indicates that the extra

// instance memory is not yet allocated to any holders.

Py_SET_SIZE(result,-static_cast<int>(offsetof(instance<>,storage) + instance_size));

}

return (PyObject*)result;

}

static PyObject* instance_get_dict(PyObject* op, void*)

{

instance<>* inst = downcast<instance<> >(op);

if (inst->dict == 0)

inst->dict = PyDict_New();

return python::xincref(inst->dict);

}

static int instance_set_dict(PyObject* op, PyObject* dict, void*)

{

instance<>* inst = downcast<instance<> >(op);

python::xdecref(inst->dict);

inst->dict = python::incref(dict);

return 0;

}

static PyGetSetDef instance_getsets[] = {

{const_cast<char*>("__dict__"), instance_get_dict, instance_set_dict, NULL, 0},

{0, 0, 0, 0, 0}

};

static PyMemberDef instance_members[] = {

{const_cast<char*>("__weakref__"), T_OBJECT, offsetof(instance<>, weakrefs), 0, 0},

{0, 0, 0, 0, 0}

};

static PyTypeObject class_type_object = {

PyVarObject_HEAD_INIT(NULL, 0)

const_cast<char*>("Boost.Python.instance"),

offsetof(instance<>,storage), /* tp_basicsize */

1, /* tp_itemsize */

instance_dealloc, /* 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 */

offsetof(instance<>,weakrefs), /* tp_weaklistoffset */

0, /* tp_iter */

0, /* tp_iternext */

0, /* tp_methods */

instance_members, /* tp_members */

instance_getsets, /* tp_getset */

0, //&PyBaseObject_Type, /* tp_base */

0, /* tp_dict */

0, /* tp_descr_get */

0, /* tp_descr_set */

offsetof(instance<>,dict), /* tp_dictoffset */

0, /* tp_init */

PyType_GenericAlloc, /* tp_alloc */

instance_new, /* tp_new */

0, /* tp_free */

0, /* tp_is_gc */

0, /* tp_bases */

0, /* tp_mro */

0, /* tp_cache */

0, /* tp_subclasses */

0, /* tp_weaklist */

#if PYTHON_API_VERSION >= 1012

0 /* tp_del */

#endif

};

BOOST_PYTHON_DECL type_handle class_type()

{

if (class_type_object.tp_dict == 0)

{

Py_SET_TYPE(&class_type_object, incref(class_metatype().get()));

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));

}

BOOST_PYTHON_DECL void*

find_instance_impl(PyObject* inst, type_info type, bool null_shared_ptr_only)

{

if (!Py_TYPE(Py_TYPE(inst)) ||

!PyType_IsSubtype(Py_TYPE(Py_TYPE(inst)), &class_metatype_object))

return 0;

instance<>* self = reinterpret_cast<instance<>*>(inst);

for (instance_holder* match = self->objects; match != 0; match = match->next())

{

void* const found = match->holds(type, null_shared_ptr_only);

if (found)

return found;

}

return 0;

}

object module_prefix()

{

return object(

PyObject_IsInstance(scope().ptr(), upcast<PyObject>(&PyModule_Type))

? object(scope().attr("__name__"))

: api::getattr(scope(), "__module__", str())

);

}

object qualname(const char *name)

{

#if PY_VERSION_HEX >= 0x03030000

if (PyObject_HasAttrString(scope().ptr(), "__qualname__")) {

return str("%s.%s" % make_tuple(scope().attr("__qualname__"), name));

}

#endif

return str(name);

}

namespace

{

// Find a registered class object corresponding to id. Return a

// null handle if no such class is registered.

inline type_handle query_class(type_info id)

{

converter::registration const* p = converter::registry::query(id);

return type_handle(

python::borrowed(

python::allow_null(p ? p->m_class_object : 0))

);

}

// Find a registered class corresponding to id. If not found,

// throw an appropriate exception.

type_handle get_class(type_info id)

{

type_handle result(query_class(id));

if (result.get() == 0)

{

object report("extension class wrapper for base class ");

report = report + id.name() + " has not been created yet";

PyErr_SetObject(PyExc_RuntimeError, report.ptr());

throw_error_already_set();

}

return result;

}

// class_base constructor

// name - the name of the new Python class

// num_types - one more than the number of declared bases

// types - array of python::type_info, the first item

// corresponding to the class being created, and the

// rest corresponding to its declared bases.

inline object

new_class(char const* name, std::size_t num_types, type_info const* const types, char const* doc)

{

assert(num_types >= 1);

// Build a tuple of the base Python type objects. If no bases

// were declared, we'll use our class_type() as the single base

// class.

ssize_t const num_bases = (std::max)(num_types - 1, static_cast<std::size_t>(1));

handle<> bases(PyTuple_New(num_bases));

for (ssize_t i = 1; i <= num_bases; ++i)

{

type_handle c = (i >= static_cast<ssize_t>(num_types)) ? class_type() : get_class(types[i]);

// PyTuple_SET_ITEM steals this reference

PyTuple_SET_ITEM(bases.get(), static_cast<ssize_t>(i - 1), upcast<PyObject>(c.release()));

}

// Call the class metatype to create a new class

dict d;

object m = module_prefix();

if (m) d["__module__"] = m;

#if PY_VERSION_HEX >= 0x03030000

d["__qualname__"] = qualname(name);

#endif

if (doc != 0)

d["__doc__"] = doc;

object result = object(class_metatype())(name, bases, d);

assert(PyType_IsSubtype(Py_TYPE(result.ptr()), &PyType_Type));

if (scope().ptr() != Py_None)

scope().attr(name) = result;

// For pickle. Will lead to informative error messages if pickling

// is not enabled.

result.attr("__reduce__") = object(make_instance_reduce_function());

return result;

}

class_base::class_base(

char const* name, std::size_t num_types, type_info const* const types, char const* doc)

: object(new_class(name, num_types, types, doc))

{

// Insert the new class object in the registry

converter::registration& converters = const_cast<converter::registration&>(

converter::registry::lookup(types[0]));

// Class object is leaked, for now

converters.m_class_object = (PyTypeObject*)incref(this->ptr());

}

BOOST_PYTHON_DECL void copy_class_object(type_info const& src, type_info const& dst)

{

converter::registration& dst_converters

= const_cast<converter::registration&>(converter::registry::lookup(dst));

converter::registration const& src_converters = converter::registry::lookup(src);

dst_converters.m_class_object = src_converters.m_class_object;

}

void class_base::set_instance_size(std::size_t instance_size)

{

this->attr("__instance_size__") = instance_size;

}

void class_base::add_property(

char const* name, object const& fget, char const* docstr)

{

object property(

(python::detail::new_reference)

PyObject_CallFunction((PyObject*)&PyProperty_Type, const_cast<char*>("Osss"), fget.ptr(), (char*)NULL, (char*)NULL, docstr));

this->setattr(name, property);

}

void class_base::add_property(

char const* name, object const& fget, object const& fset, char const* docstr)

{

object property(

(python::detail::new_reference)

PyObject_CallFunction((PyObject*)&PyProperty_Type, const_cast<char*>("OOss"), fget.ptr(), fset.ptr(), (char*)NULL, docstr));

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(), const_cast<char*>("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(), const_cast<char*>("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)

throw_error_already_set();

}

namespace

{

extern "C" PyObject* no_init(PyObject*, PyObject*)

{

::PyErr_SetString(::PyExc_RuntimeError, const_cast<char*>("This class cannot be instantiated from Python"));

return NULL;

}

static ::PyMethodDef no_init_def = {

const_cast<char*>("__init__"), no_init, METH_VARARGS,

const_cast<char*>("Raises an exception\n"

"This class cannot be instantiated from Python\n")

};

}

void class_base::def_no_init()

{

handle<> f(::PyCFunction_New(&no_init_def, 0));

this->setattr("__init__", object(f));

}

void class_base::enable_pickling_(bool getstate_manages_dict)

{

setattr("__safe_for_unpickling__", object(true));

if (getstate_manages_dict)

{

setattr("__getstate_manages_dict__", object(true));

}

namespace

{

PyObject* callable_check(PyObject* callable)

{

if (PyCallable_Check(expect_non_null(callable)))

return callable;

::PyErr_Format(

PyExc_TypeError

, const_cast<char*>("staticmethod expects callable object; got an object of type %s, which is not callable")

, Py_TYPE(callable)->tp_name

);

throw_error_already_set();

return 0;

}

void class_base::make_method_static(const char * method_name)

{

PyTypeObject* self = downcast<PyTypeObject>(this->ptr());

dict d((handle<>(borrowed(self->tp_dict))));

object method(d[method_name]);

this->attr(method_name) = object(

handle<>(

PyStaticMethod_New((callable_check)(method.ptr()) )

));

}

BOOST_PYTHON_DECL type_handle registered_class_object(type_info id)

{

return query_class(id);

}

} // namespace objects

typedef unsigned int alignment_marker_t;

void* instance_holder::allocate(PyObject* self_, std::size_t holder_offset, std::size_t holder_size, std::size_t alignment)

{

assert(PyType_IsSubtype(Py_TYPE(Py_TYPE(self_)), &class_metatype_object));

objects::instance<>* self = (objects::instance<>*)self_;

int total_size_needed = holder_offset + holder_size + alignment - 1;

if (-Py_SIZE(self) >= total_size_needed)

{

// holder_offset should at least point into the variable-sized part

assert(holder_offset >= offsetof(objects::instance<>,storage));

size_t allocated = holder_size + alignment;

void* storage = (char*)self + holder_offset;

void* aligned_storage = ::boost::alignment::align(alignment, holder_size, storage, allocated);

// Record the fact that the storage is occupied, noting where it starts

const size_t offset = reinterpret_cast<uintptr_t>(aligned_storage) - reinterpret_cast<uintptr_t>(storage) + holder_offset;

Py_SET_SIZE(self, offset);

return (char*)self + offset;

}

else

{

const size_t base_allocation = sizeof(alignment_marker_t) + holder_size + alignment - 1;

void* const base_storage = PyMem_Malloc(base_allocation);

if (base_storage == 0)

throw std::bad_alloc();

const uintptr_t x = reinterpret_cast<uintptr_t>(base_storage) + sizeof(alignment_marker_t);

// Padding required to align the start of a data structure is: (alignment - (x % alignment)) % alignment

// Since the alignment is a power of two, the formula can be simplified with bitwise AND operator as follow:

const uintptr_t padding = (alignment - (x & (alignment - 1))) & (alignment - 1);

const size_t aligned_offset = sizeof(alignment_marker_t) + padding;

void* const aligned_storage = (char *)base_storage + aligned_offset;

BOOST_ASSERT((char *) aligned_storage + holder_size <= (char *)base_storage + base_allocation);

alignment_marker_t* const marker_storage = reinterpret_cast<alignment_marker_t *>((char *)aligned_storage - sizeof(alignment_marker_t));

*marker_storage = static_cast<alignment_marker_t>(padding);

return aligned_storage;

}

void instance_holder::deallocate(PyObject* self_, void* storage) throw()

{

assert(PyType_IsSubtype(Py_TYPE(Py_TYPE(self_)), &class_metatype_object));

objects::instance<>* self = (objects::instance<>*)self_;

if (storage != (char*)self + Py_SIZE(self))

{

alignment_marker_t* marker_storage = reinterpret_cast<alignment_marker_t *>((char *)storage - sizeof(alignment_marker_t));

void *malloced_storage = (char *) storage - sizeof(alignment_marker_t) - (*marker_storage);

PyMem_Free(malloced_storage);

}

}} // namespace boost::python

python/src/object/class.cpp at python313 · boostorg/python · GitHub

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