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_ctypes.c
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5421 lines (4835 loc) · 136 KB
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/*
ToDo:
Get rid of the checker (and also the converters) field in PyCFuncPtrObject and
StgDictObject, and replace them by slot functions in StgDictObject.
think about a buffer-like object (memory? bytes?)
Should POINTER(c_char) and POINTER(c_wchar) have a .value property?
What about c_char and c_wchar arrays then?
Add from_mmap, from_file, from_string metaclass methods.
Maybe we can get away with from_file (calls read) and with a from_buffer
method?
And what about the to_mmap, to_file, to_str(?) methods? They would clobber
the namespace, probably. So, functions instead? And we already have memmove...
*/
/*
Name methods, members, getsets
==============================================================================
PyCStructType_Type __new__(), from_address(), __mul__(), from_param()
UnionType_Type __new__(), from_address(), __mul__(), from_param()
PyCPointerType_Type __new__(), from_address(), __mul__(), from_param(), set_type()
PyCArrayType_Type __new__(), from_address(), __mul__(), from_param()
PyCSimpleType_Type __new__(), from_address(), __mul__(), from_param()
PyCData_Type
Struct_Type __new__(), __init__()
PyCPointer_Type __new__(), __init__(), _as_parameter_, contents
PyCArray_Type __new__(), __init__(), _as_parameter_, __get/setitem__(), __len__()
Simple_Type __new__(), __init__(), _as_parameter_
PyCField_Type
PyCStgDict_Type
==============================================================================
class methods
-------------
It has some similarity to the byref() construct compared to pointer()
from_address(addr)
- construct an instance from a given memory block (sharing this memory block)
from_param(obj)
- typecheck and convert a Python object into a C function call parameter
the result may be an instance of the type, or an integer or tuple
(typecode, value[, obj])
instance methods/properties
---------------------------
_as_parameter_
- convert self into a C function call parameter
This is either an integer, or a 3-tuple (typecode, value, obj)
functions
---------
sizeof(cdata)
- return the number of bytes the buffer contains
sizeof(ctype)
- return the number of bytes the buffer of an instance would contain
byref(cdata)
addressof(cdata)
pointer(cdata)
POINTER(ctype)
bytes(cdata)
- return the buffer contents as a sequence of bytes (which is currently a string)
*/
/*
* PyCStgDict_Type
* PyCStructType_Type
* UnionType_Type
* PyCPointerType_Type
* PyCArrayType_Type
* PyCSimpleType_Type
*
* PyCData_Type
* Struct_Type
* Union_Type
* PyCArray_Type
* Simple_Type
* PyCPointer_Type
* PyCField_Type
*
*/
#define PY_SSIZE_T_CLEAN
#include "Python.h"
#include "structmember.h"
#include <ffi.h>
#ifdef MS_WIN32
#include <windows.h>
#include <malloc.h>
#ifndef IS_INTRESOURCE
#define IS_INTRESOURCE(x) (((size_t)(x) >> 16) == 0)
#endif
# ifdef _WIN32_WCE
/* Unlike desktop Windows, WinCE has both W and A variants of
GetProcAddress, but the default W version is not what we want */
# undef GetProcAddress
# define GetProcAddress GetProcAddressA
# endif
#else
#include "ctypes_dlfcn.h"
#endif
#include "ctypes.h"
PyObject *PyExc_ArgError;
/* This dict maps ctypes types to POINTER types */
PyObject *_ctypes_ptrtype_cache;
static PyTypeObject Simple_Type;
/* a callable object used for unpickling */
static PyObject *_unpickle;
char *_ctypes_conversion_encoding = NULL;
char *_ctypes_conversion_errors = NULL;
/****************************************************************/
typedef struct {
PyObject_HEAD
PyObject *key;
PyObject *dict;
} DictRemoverObject;
static void
_DictRemover_dealloc(PyObject *_self)
{
DictRemoverObject *self = (DictRemoverObject *)_self;
Py_XDECREF(self->key);
Py_XDECREF(self->dict);
Py_TYPE(self)->tp_free(_self);
}
static PyObject *
_DictRemover_call(PyObject *_self, PyObject *args, PyObject *kw)
{
DictRemoverObject *self = (DictRemoverObject *)_self;
if (self->key && self->dict) {
if (-1 == PyDict_DelItem(self->dict, self->key))
/* XXX Error context */
PyErr_WriteUnraisable(Py_None);
Py_DECREF(self->key);
self->key = NULL;
Py_DECREF(self->dict);
self->dict = NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
static PyTypeObject DictRemover_Type = {
PyVarObject_HEAD_INIT(NULL, 0)
"_ctypes.DictRemover", /* tp_name */
sizeof(DictRemoverObject), /* tp_basicsize */
0, /* tp_itemsize */
_DictRemover_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
_DictRemover_call, /* tp_call */
0, /* tp_str */
0, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
/* XXX should participate in GC? */
Py_TPFLAGS_DEFAULT, /* tp_flags */
"deletes a key from a dictionary", /* 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, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
0, /* tp_new */
0, /* tp_free */
};
int
PyDict_SetItemProxy(PyObject *dict, PyObject *key, PyObject *item)
{
PyObject *obj;
DictRemoverObject *remover;
PyObject *proxy;
int result;
obj = PyObject_CallObject((PyObject *)&DictRemover_Type, NULL);
if (obj == NULL)
return -1;
remover = (DictRemoverObject *)obj;
assert(remover->key == NULL);
assert(remover->dict == NULL);
Py_INCREF(key);
remover->key = key;
Py_INCREF(dict);
remover->dict = dict;
proxy = PyWeakref_NewProxy(item, obj);
Py_DECREF(obj);
if (proxy == NULL)
return -1;
result = PyDict_SetItem(dict, key, proxy);
Py_DECREF(proxy);
return result;
}
PyObject *
PyDict_GetItemProxy(PyObject *dict, PyObject *key)
{
PyObject *result;
PyObject *item = PyDict_GetItem(dict, key);
if (item == NULL)
return NULL;
if (!PyWeakref_CheckProxy(item))
return item;
result = PyWeakref_GET_OBJECT(item);
if (result == Py_None)
return NULL;
return result;
}
/******************************************************************/
/*
Allocate a memory block for a pep3118 format string, copy prefix (if
non-null) and suffix into it. Returns NULL on failure, with the error
indicator set. If called with a suffix of NULL the error indicator must
already be set.
*/
char *
_ctypes_alloc_format_string(const char *prefix, const char *suffix)
{
size_t len;
char *result;
if (suffix == NULL) {
assert(PyErr_Occurred());
return NULL;
}
len = strlen(suffix);
if (prefix)
len += strlen(prefix);
result = PyMem_Malloc(len + 1);
if (result == NULL)
return NULL;
if (prefix)
strcpy(result, prefix);
else
result[0] = '\0';
strcat(result, suffix);
return result;
}
/*
PyCStructType_Type - a meta type/class. Creating a new class using this one as
__metaclass__ will call the contructor StructUnionType_new. It replaces the
tp_dict member with a new instance of StgDict, and initializes the C
accessible fields somehow.
*/
static PyCArgObject *
StructUnionType_paramfunc(CDataObject *self)
{
PyCArgObject *parg;
StgDictObject *stgdict;
parg = PyCArgObject_new();
if (parg == NULL)
return NULL;
parg->tag = 'V';
stgdict = PyObject_stgdict((PyObject *)self);
assert(stgdict); /* Cannot be NULL for structure/union instances */
parg->pffi_type = &stgdict->ffi_type_pointer;
/* For structure parameters (by value), parg->value doesn't contain the structure
data itself, instead parg->value.p *points* to the structure's data
See also _ctypes.c, function _call_function_pointer().
*/
parg->value.p = self->b_ptr;
parg->size = self->b_size;
Py_INCREF(self);
parg->obj = (PyObject *)self;
return parg;
}
static PyObject *
StructUnionType_new(PyTypeObject *type, PyObject *args, PyObject *kwds, int isStruct)
{
PyTypeObject *result;
PyObject *fields;
StgDictObject *dict;
/* create the new instance (which is a class,
since we are a metatype!) */
result = (PyTypeObject *)PyType_Type.tp_new(type, args, kwds);
if (!result)
return NULL;
/* keep this for bw compatibility */
if (PyDict_GetItemString(result->tp_dict, "_abstract_"))
return (PyObject *)result;
dict = (StgDictObject *)PyObject_CallObject((PyObject *)&PyCStgDict_Type, NULL);
if (!dict) {
Py_DECREF(result);
return NULL;
}
/* replace the class dict by our updated stgdict, which holds info
about storage requirements of the instances */
if (-1 == PyDict_Update((PyObject *)dict, result->tp_dict)) {
Py_DECREF(result);
Py_DECREF((PyObject *)dict);
return NULL;
}
Py_DECREF(result->tp_dict);
result->tp_dict = (PyObject *)dict;
dict->format = _ctypes_alloc_format_string(NULL, "B");
if (dict->format == NULL) {
Py_DECREF(result);
return NULL;
}
dict->paramfunc = StructUnionType_paramfunc;
fields = PyDict_GetItemString((PyObject *)dict, "_fields_");
if (!fields) {
StgDictObject *basedict = PyType_stgdict((PyObject *)result->tp_base);
if (basedict == NULL)
return (PyObject *)result;
/* copy base dict */
if (-1 == PyCStgDict_clone(dict, basedict)) {
Py_DECREF(result);
return NULL;
}
dict->flags &= ~DICTFLAG_FINAL; /* clear the 'final' flag in the subclass dict */
basedict->flags |= DICTFLAG_FINAL; /* set the 'final' flag in the baseclass dict */
return (PyObject *)result;
}
if (-1 == PyObject_SetAttrString((PyObject *)result, "_fields_", fields)) {
Py_DECREF(result);
return NULL;
}
return (PyObject *)result;
}
static PyObject *
PyCStructType_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
return StructUnionType_new(type, args, kwds, 1);
}
static PyObject *
UnionType_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
return StructUnionType_new(type, args, kwds, 0);
}
static char from_address_doc[] =
"C.from_address(integer) -> C instance\naccess a C instance at the specified address";
static PyObject *
CDataType_from_address(PyObject *type, PyObject *value)
{
void *buf;
if (!PyLong_Check(value)) {
PyErr_SetString(PyExc_TypeError,
"integer expected");
return NULL;
}
buf = (void *)PyLong_AsVoidPtr(value);
if (PyErr_Occurred())
return NULL;
return PyCData_AtAddress(type, buf);
}
static char from_buffer_doc[] =
"C.from_buffer(object, offset=0) -> C instance\ncreate a C instance from a writeable buffer";
static int
KeepRef(CDataObject *target, Py_ssize_t index, PyObject *keep);
static PyObject *
CDataType_from_buffer(PyObject *type, PyObject *args)
{
void *buffer;
Py_ssize_t buffer_len;
Py_ssize_t offset = 0;
PyObject *obj, *result;
StgDictObject *dict = PyType_stgdict(type);
assert (dict);
if (!PyArg_ParseTuple(args,
#if (PY_VERSION_HEX < 0x02050000)
"O|i:from_buffer",
#else
"O|n:from_buffer",
#endif
&obj, &offset))
return NULL;
if (-1 == PyObject_AsWriteBuffer(obj, &buffer, &buffer_len))
return NULL;
if (offset < 0) {
PyErr_SetString(PyExc_ValueError,
"offset cannot be negative");
return NULL;
}
if (dict->size > buffer_len - offset) {
PyErr_Format(PyExc_ValueError,
#if (PY_VERSION_HEX < 0x02050000)
"Buffer size too small (%d instead of at least %d bytes)",
#else
"Buffer size too small (%zd instead of at least %zd bytes)",
#endif
buffer_len, dict->size + offset);
return NULL;
}
result = PyCData_AtAddress(type, (char *)buffer + offset);
if (result == NULL)
return NULL;
Py_INCREF(obj);
if (-1 == KeepRef((CDataObject *)result, -1, obj)) {
Py_DECREF(result);
return NULL;
}
return result;
}
static char from_buffer_copy_doc[] =
"C.from_buffer_copy(object, offset=0) -> C instance\ncreate a C instance from a readable buffer";
static PyObject *
GenericPyCData_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
static PyObject *
CDataType_from_buffer_copy(PyObject *type, PyObject *args)
{
const void *buffer;
Py_ssize_t buffer_len;
Py_ssize_t offset = 0;
PyObject *obj, *result;
StgDictObject *dict = PyType_stgdict(type);
assert (dict);
if (!PyArg_ParseTuple(args,
#if (PY_VERSION_HEX < 0x02050000)
"O|i:from_buffer",
#else
"O|n:from_buffer",
#endif
&obj, &offset))
return NULL;
if (-1 == PyObject_AsReadBuffer(obj, (const void**)&buffer, &buffer_len))
return NULL;
if (offset < 0) {
PyErr_SetString(PyExc_ValueError,
"offset cannot be negative");
return NULL;
}
if (dict->size > buffer_len - offset) {
PyErr_Format(PyExc_ValueError,
#if (PY_VERSION_HEX < 0x02050000)
"Buffer size too small (%d instead of at least %d bytes)",
#else
"Buffer size too small (%zd instead of at least %zd bytes)",
#endif
buffer_len, dict->size + offset);
return NULL;
}
result = GenericPyCData_new((PyTypeObject *)type, NULL, NULL);
if (result == NULL)
return NULL;
memcpy(((CDataObject *)result)->b_ptr,
(char *)buffer+offset, dict->size);
return result;
}
static char in_dll_doc[] =
"C.in_dll(dll, name) -> C instance\naccess a C instance in a dll";
static PyObject *
CDataType_in_dll(PyObject *type, PyObject *args)
{
PyObject *dll;
char *name;
PyObject *obj;
void *handle;
void *address;
if (!PyArg_ParseTuple(args, "Os:in_dll", &dll, &name))
return NULL;
obj = PyObject_GetAttrString(dll, "_handle");
if (!obj)
return NULL;
if (!PyLong_Check(obj)) {
PyErr_SetString(PyExc_TypeError,
"the _handle attribute of the second argument must be an integer");
Py_DECREF(obj);
return NULL;
}
handle = (void *)PyLong_AsVoidPtr(obj);
Py_DECREF(obj);
if (PyErr_Occurred()) {
PyErr_SetString(PyExc_ValueError,
"could not convert the _handle attribute to a pointer");
return NULL;
}
#ifdef MS_WIN32
address = (void *)GetProcAddress(handle, name);
if (!address) {
PyErr_Format(PyExc_ValueError,
"symbol '%s' not found",
name);
return NULL;
}
#else
address = (void *)ctypes_dlsym(handle, name);
if (!address) {
#ifdef __CYGWIN__
/* dlerror() isn't very helpful on cygwin */
PyErr_Format(PyExc_ValueError,
"symbol '%s' not found (%s) ",
name);
#else
PyErr_SetString(PyExc_ValueError, ctypes_dlerror());
#endif
return NULL;
}
#endif
return PyCData_AtAddress(type, address);
}
static char from_param_doc[] =
"Convert a Python object into a function call parameter.";
static PyObject *
CDataType_from_param(PyObject *type, PyObject *value)
{
PyObject *as_parameter;
if (1 == PyObject_IsInstance(value, type)) {
Py_INCREF(value);
return value;
}
if (PyCArg_CheckExact(value)) {
PyCArgObject *p = (PyCArgObject *)value;
PyObject *ob = p->obj;
const char *ob_name;
StgDictObject *dict;
dict = PyType_stgdict(type);
/* If we got a PyCArgObject, we must check if the object packed in it
is an instance of the type's dict->proto */
if(dict && ob
&& PyObject_IsInstance(ob, dict->proto)) {
Py_INCREF(value);
return value;
}
ob_name = (ob) ? Py_TYPE(ob)->tp_name : "???";
PyErr_Format(PyExc_TypeError,
"expected %s instance instead of pointer to %s",
((PyTypeObject *)type)->tp_name, ob_name);
return NULL;
}
as_parameter = PyObject_GetAttrString(value, "_as_parameter_");
if (as_parameter) {
value = CDataType_from_param(type, as_parameter);
Py_DECREF(as_parameter);
return value;
}
PyErr_Format(PyExc_TypeError,
"expected %s instance instead of %s",
((PyTypeObject *)type)->tp_name,
Py_TYPE(value)->tp_name);
return NULL;
}
static PyMethodDef CDataType_methods[] = {
{ "from_param", CDataType_from_param, METH_O, from_param_doc },
{ "from_address", CDataType_from_address, METH_O, from_address_doc },
{ "from_buffer", CDataType_from_buffer, METH_VARARGS, from_buffer_doc, },
{ "from_buffer_copy", CDataType_from_buffer_copy, METH_VARARGS, from_buffer_copy_doc, },
{ "in_dll", CDataType_in_dll, METH_VARARGS, in_dll_doc },
{ NULL, NULL },
};
static PyObject *
CDataType_repeat(PyObject *self, Py_ssize_t length)
{
if (length < 0)
return PyErr_Format(PyExc_ValueError,
"Array length must be >= 0, not %zd",
length);
return PyCArrayType_from_ctype(self, length);
}
static PySequenceMethods CDataType_as_sequence = {
0, /* inquiry sq_length; */
0, /* binaryfunc sq_concat; */
CDataType_repeat, /* intargfunc sq_repeat; */
0, /* intargfunc sq_item; */
0, /* intintargfunc sq_slice; */
0, /* intobjargproc sq_ass_item; */
0, /* intintobjargproc sq_ass_slice; */
0, /* objobjproc sq_contains; */
0, /* binaryfunc sq_inplace_concat; */
0, /* intargfunc sq_inplace_repeat; */
};
static int
CDataType_clear(PyTypeObject *self)
{
StgDictObject *dict = PyType_stgdict((PyObject *)self);
if (dict)
Py_CLEAR(dict->proto);
return PyType_Type.tp_clear((PyObject *)self);
}
static int
CDataType_traverse(PyTypeObject *self, visitproc visit, void *arg)
{
StgDictObject *dict = PyType_stgdict((PyObject *)self);
if (dict)
Py_VISIT(dict->proto);
return PyType_Type.tp_traverse((PyObject *)self, visit, arg);
}
static int
PyCStructType_setattro(PyObject *self, PyObject *key, PyObject *value)
{
/* XXX Should we disallow deleting _fields_? */
if (-1 == PyType_Type.tp_setattro(self, key, value))
return -1;
if (value && PyUnicode_Check(key) &&
/* XXX struni _PyUnicode_AsString can fail (also in other places)! */
0 == strcmp(_PyUnicode_AsString(key), "_fields_"))
return PyCStructUnionType_update_stgdict(self, value, 1);
return 0;
}
static int
UnionType_setattro(PyObject *self, PyObject *key, PyObject *value)
{
/* XXX Should we disallow deleting _fields_? */
if (-1 == PyObject_GenericSetAttr(self, key, value))
return -1;
if (PyUnicode_Check(key) &&
0 == strcmp(_PyUnicode_AsString(key), "_fields_"))
return PyCStructUnionType_update_stgdict(self, value, 0);
return 0;
}
PyTypeObject PyCStructType_Type = {
PyVarObject_HEAD_INIT(NULL, 0)
"_ctypes.PyCStructType", /* tp_name */
0, /* tp_basicsize */
0, /* tp_itemsize */
0, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
0, /* tp_repr */
0, /* tp_as_number */
&CDataType_as_sequence, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
0, /* tp_getattro */
PyCStructType_setattro, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC, /* tp_flags */
"metatype for the CData Objects", /* tp_doc */
(traverseproc)CDataType_traverse, /* tp_traverse */
(inquiry)CDataType_clear, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
CDataType_methods, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
PyCStructType_new, /* tp_new */
0, /* tp_free */
};
static PyTypeObject UnionType_Type = {
PyVarObject_HEAD_INIT(NULL, 0)
"_ctypes.UnionType", /* tp_name */
0, /* tp_basicsize */
0, /* tp_itemsize */
0, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
0, /* tp_repr */
0, /* tp_as_number */
&CDataType_as_sequence, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
0, /* tp_getattro */
UnionType_setattro, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC, /* tp_flags */
"metatype for the CData Objects", /* tp_doc */
(traverseproc)CDataType_traverse, /* tp_traverse */
(inquiry)CDataType_clear, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
CDataType_methods, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
UnionType_new, /* tp_new */
0, /* tp_free */
};
/******************************************************************/
/*
The PyCPointerType_Type metaclass must ensure that the subclass of Pointer can be
created. It must check for a _type_ attribute in the class. Since are no
runtime created properties, a CField is probably *not* needed ?
class IntPointer(Pointer):
_type_ = "i"
The PyCPointer_Type provides the functionality: a contents method/property, a
size property/method, and the sequence protocol.
*/
static int
PyCPointerType_SetProto(StgDictObject *stgdict, PyObject *proto)
{
if (!proto || !PyType_Check(proto)) {
PyErr_SetString(PyExc_TypeError,
"_type_ must be a type");
return -1;
}
if (!PyType_stgdict(proto)) {
PyErr_SetString(PyExc_TypeError,
"_type_ must have storage info");
return -1;
}
Py_INCREF(proto);
Py_XDECREF(stgdict->proto);
stgdict->proto = proto;
return 0;
}
static PyCArgObject *
PyCPointerType_paramfunc(CDataObject *self)
{
PyCArgObject *parg;
parg = PyCArgObject_new();
if (parg == NULL)
return NULL;
parg->tag = 'P';
parg->pffi_type = &ffi_type_pointer;
Py_INCREF(self);
parg->obj = (PyObject *)self;
parg->value.p = *(void **)self->b_ptr;
return parg;
}
static PyObject *
PyCPointerType_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
PyTypeObject *result;
StgDictObject *stgdict;
PyObject *proto;
PyObject *typedict;
typedict = PyTuple_GetItem(args, 2);
if (!typedict)
return NULL;
/*
stgdict items size, align, length contain info about pointers itself,
stgdict->proto has info about the pointed to type!
*/
stgdict = (StgDictObject *)PyObject_CallObject(
(PyObject *)&PyCStgDict_Type, NULL);
if (!stgdict)
return NULL;
stgdict->size = sizeof(void *);
stgdict->align = _ctypes_get_fielddesc("P")->pffi_type->alignment;
stgdict->length = 1;
stgdict->ffi_type_pointer = ffi_type_pointer;
stgdict->paramfunc = PyCPointerType_paramfunc;
stgdict->flags |= TYPEFLAG_ISPOINTER;
proto = PyDict_GetItemString(typedict, "_type_"); /* Borrowed ref */
if (proto && -1 == PyCPointerType_SetProto(stgdict, proto)) {
Py_DECREF((PyObject *)stgdict);
return NULL;
}
if (proto) {
StgDictObject *itemdict = PyType_stgdict(proto);
assert(itemdict);
/* If itemdict->format is NULL, then this is a pointer to an
incomplete type. We create a generic format string
'pointer to bytes' in this case. XXX Better would be to
fix the format string later...
*/
stgdict->format = _ctypes_alloc_format_string("&",
itemdict->format ? itemdict->format : "B");
if (stgdict->format == NULL) {
Py_DECREF((PyObject *)stgdict);
return NULL;
}
}
/* create the new instance (which is a class,
since we are a metatype!) */
result = (PyTypeObject *)PyType_Type.tp_new(type, args, kwds);
if (result == NULL) {
Py_DECREF((PyObject *)stgdict);
return NULL;
}
/* replace the class dict by our updated spam dict */
if (-1 == PyDict_Update((PyObject *)stgdict, result->tp_dict)) {
Py_DECREF(result);
Py_DECREF((PyObject *)stgdict);
return NULL;
}
Py_DECREF(result->tp_dict);
result->tp_dict = (PyObject *)stgdict;
return (PyObject *)result;
}
static PyObject *
PyCPointerType_set_type(PyTypeObject *self, PyObject *type)
{
StgDictObject *dict;
dict = PyType_stgdict((PyObject *)self);
assert(dict);
if (-1 == PyCPointerType_SetProto(dict, type))
return NULL;
if (-1 == PyDict_SetItemString((PyObject *)dict, "_type_", type))
return NULL;
Py_INCREF(Py_None);
return Py_None;
}
static PyObject *_byref(PyObject *);
static PyObject *
PyCPointerType_from_param(PyObject *type, PyObject *value)
{
StgDictObject *typedict;
if (value == Py_None)
return PyLong_FromLong(0); /* NULL pointer */
typedict = PyType_stgdict(type);
assert(typedict); /* Cannot be NULL for pointer types */
/* If we expect POINTER(<type>), but receive a <type> instance, accept
it by calling byref(<type>).
*/
switch (PyObject_IsInstance(value, typedict->proto)) {
case 1:
Py_INCREF(value); /* _byref steals a refcount */
return _byref(value);
case -1:
PyErr_Clear();
break;
default:
break;
}
if (PointerObject_Check(value) || ArrayObject_Check(value)) {
/* Array instances are also pointers when
the item types are the same.
*/
StgDictObject *v = PyObject_stgdict(value);
assert(v); /* Cannot be NULL for pointer or array objects */
if (PyObject_IsSubclass(v->proto, typedict->proto)) {
Py_INCREF(value);
return value;
}
}
return CDataType_from_param(type, value);
}
static PyMethodDef PyCPointerType_methods[] = {
{ "from_address", CDataType_from_address, METH_O, from_address_doc },
{ "from_buffer", CDataType_from_buffer, METH_VARARGS, from_buffer_doc, },
{ "from_buffer_copy", CDataType_from_buffer_copy, METH_VARARGS, from_buffer_copy_doc, },
{ "in_dll", CDataType_in_dll, METH_VARARGS, in_dll_doc},
{ "from_param", (PyCFunction)PyCPointerType_from_param, METH_O, from_param_doc},
{ "set_type", (PyCFunction)PyCPointerType_set_type, METH_O },
{ NULL, NULL },
};
PyTypeObject PyCPointerType_Type = {
PyVarObject_HEAD_INIT(NULL, 0)
"_ctypes.PyCPointerType", /* tp_name */
0, /* tp_basicsize */
0, /* tp_itemsize */
0, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
0, /* tp_repr */
0, /* tp_as_number */
&CDataType_as_sequence, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
0, /* tp_getattro */