[Python-checkins] r62481 - in python/trunk: Misc/NEWS Modules/_ctypes/_ctypes.c Modules/_ctypes/callbacks.c Modules/_ctypes/ctypes.h
thomas.heller
python-checkins at python.org
Thu Apr 24 20:14:47 CEST 2008
Author: thomas.heller
Date: Thu Apr 24 20:14:19 2008
New Revision: 62481
Log:
Remove cyclic reference in CFuncPtr instances; see issue #2682.
Backport candidate for the release25-maint branch.
Modified:
python/trunk/Misc/NEWS
python/trunk/Modules/_ctypes/_ctypes.c
python/trunk/Modules/_ctypes/callbacks.c
python/trunk/Modules/_ctypes/ctypes.h
Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS (original)
+++ python/trunk/Misc/NEWS Thu Apr 24 20:14:19 2008
@@ -43,6 +43,9 @@
Library
-------
+- Issue #2682: ctypes callback functions now longer contain a cyclic
+ reference to themselves.
+
- The getpass module has been improved on Unix. It now uses /dev/tty
by default and uses stderr instead of stdout. A GetPassWarning is
issued when input echo cannot be controlled.
Modified: python/trunk/Modules/_ctypes/_ctypes.c
==============================================================================
--- python/trunk/Modules/_ctypes/_ctypes.c (original)
+++ python/trunk/Modules/_ctypes/_ctypes.c Thu Apr 24 20:14:19 2008
@@ -3096,7 +3096,7 @@
CFuncPtrObject *self;
PyObject *callable;
StgDictObject *dict;
- ffi_info *thunk;
+ CThunkObject *thunk;
if (PyTuple_GET_SIZE(args) == 0)
return GenericCData_new(type, args, kwds);
@@ -3153,11 +3153,6 @@
return NULL;
}
- /*****************************************************************/
- /* The thunk keeps unowned references to callable and dict->argtypes
- so we have to keep them alive somewhere else: callable is kept in self,
- dict->argtypes is in the type's stgdict.
- */
thunk = AllocFunctionCallback(callable,
dict->argtypes,
dict->restype,
@@ -3166,27 +3161,22 @@
return NULL;
self = (CFuncPtrObject *)GenericCData_new(type, args, kwds);
- if (self == NULL)
+ if (self == NULL) {
+ Py_DECREF(thunk);
return NULL;
+ }
Py_INCREF(callable);
self->callable = callable;
self->thunk = thunk;
- *(void **)self->b_ptr = *(void **)thunk;
-
- /* We store ourself in self->b_objects[0], because the whole instance
- must be kept alive if stored in a structure field, for example.
- Cycle GC to the rescue! And we have a unittest proving that this works
- correctly...
- */
-
- Py_INCREF((PyObject *)self); /* for KeepRef */
- if (-1 == KeepRef((CDataObject *)self, 0, (PyObject *)self)) {
+ *(void **)self->b_ptr = (void *)thunk->pcl;
+
+ Py_INCREF((PyObject *)thunk); /* for KeepRef */
+ if (-1 == KeepRef((CDataObject *)self, 0, (PyObject *)thunk)) {
Py_DECREF((PyObject *)self);
return NULL;
}
-
return (PyObject *)self;
}
@@ -3639,6 +3629,7 @@
Py_VISIT(self->argtypes);
Py_VISIT(self->converters);
Py_VISIT(self->paramflags);
+ Py_VISIT(self->thunk);
return CData_traverse((CDataObject *)self, visit, arg);
}
@@ -3652,13 +3643,7 @@
Py_CLEAR(self->argtypes);
Py_CLEAR(self->converters);
Py_CLEAR(self->paramflags);
-
- if (self->thunk) {
- FreeClosure(self->thunk->pcl);
- PyMem_Free(self->thunk);
- self->thunk = NULL;
- }
-
+ Py_CLEAR(self->thunk);
return CData_clear((CDataObject *)self);
}
@@ -5186,6 +5171,9 @@
if (PyType_Ready(&PyCArg_Type) < 0)
return;
+ if (PyType_Ready(&CThunk_Type) < 0)
+ return;
+
/* StgDict is derived from PyDict_Type */
StgDict_Type.tp_base = &PyDict_Type;
if (PyType_Ready(&StgDict_Type) < 0)
Modified: python/trunk/Modules/_ctypes/callbacks.c
==============================================================================
--- python/trunk/Modules/_ctypes/callbacks.c (original)
+++ python/trunk/Modules/_ctypes/callbacks.c Thu Apr 24 20:14:19 2008
@@ -12,6 +12,73 @@
#endif
#include "ctypes.h"
+/**************************************************************/
+
+static CThunkObject_dealloc(PyObject *_self)
+{
+ CThunkObject *self = (CThunkObject *)_self;
+ Py_XDECREF(self->converters);
+ Py_XDECREF(self->callable);
+ Py_XDECREF(self->restype);
+ if (self->pcl)
+ FreeClosure(self->pcl);
+ PyObject_Del(self);
+}
+
+static int
+CThunkObject_traverse(PyObject *_self, visitproc visit, void *arg)
+{
+ CThunkObject *self = (CThunkObject *)_self;
+ Py_VISIT(self->converters);
+ Py_VISIT(self->callable);
+ Py_VISIT(self->restype);
+ return 0;
+}
+
+static int
+CThunkObject_clear(PyObject *_self)
+{
+ CThunkObject *self = (CThunkObject *)_self;
+ Py_CLEAR(self->converters);
+ Py_CLEAR(self->callable);
+ Py_CLEAR(self->restype);
+ return 0;
+}
+
+PyTypeObject CThunk_Type = {
+ PyVarObject_HEAD_INIT(NULL, 0)
+ "_ctypes.CThunkObject",
+ sizeof(CThunkObject), /* tp_basicsize */
+ sizeof(ffi_type), /* tp_itemsize */
+ CThunkObject_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, /* tp_flags */
+ "CThunkObject", /* tp_doc */
+ CThunkObject_traverse, /* tp_traverse */
+ CThunkObject_clear, /* tp_clear */
+ 0, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ 0, /* tp_iter */
+ 0, /* tp_iternext */
+ 0, /* tp_methods */
+ 0, /* tp_members */
+};
+
+/**************************************************************/
+
static void
PrintError(char *msg, ...)
{
@@ -247,32 +314,56 @@
void **args,
void *userdata)
{
- ffi_info *p = userdata;
+ CThunkObject *p = (CThunkObject *)userdata;
_CallPythonObject(resp,
- p->restype,
+ p->ffi_restype,
p->setfunc,
p->callable,
p->converters,
args);
}
-ffi_info *AllocFunctionCallback(PyObject *callable,
- PyObject *converters,
- PyObject *restype,
- int is_cdecl)
+static CThunkObject* CThunkObject_new(Py_ssize_t nArgs)
+{
+ CThunkObject *p;
+ int i;
+
+ p = PyObject_NewVar(CThunkObject, &CThunk_Type, nArgs);
+ if (p == NULL) {
+ PyErr_NoMemory();
+ return NULL;
+ }
+
+ p->pcl = NULL;
+ memset(&p->cif, 0, sizeof(p->cif));
+ p->converters = NULL;
+ p->callable = NULL;
+ p->setfunc = NULL;
+ p->ffi_restype = NULL;
+
+ for (i = 0; i < nArgs + 1; ++i)
+ p->atypes[i] = NULL;
+ return p;
+}
+
+CThunkObject *AllocFunctionCallback(PyObject *callable,
+ PyObject *converters,
+ PyObject *restype,
+ int is_cdecl)
{
int result;
- ffi_info *p;
+ CThunkObject *p;
Py_ssize_t nArgs, i;
ffi_abi cc;
nArgs = PySequence_Size(converters);
- p = (ffi_info *)PyMem_Malloc(sizeof(ffi_info) + sizeof(ffi_type) * (nArgs));
- if (p == NULL) {
- PyErr_NoMemory();
+ p = CThunkObject_new(nArgs);
+ if (p == NULL)
return NULL;
- }
+
+ assert(CThunk_CheckExact(p));
+
p->pcl = MallocClosure();
if (p->pcl == NULL) {
PyErr_NoMemory();
@@ -288,9 +379,11 @@
}
p->atypes[i] = NULL;
+ Py_INCREF(restype);
+ p->restype = restype;
if (restype == Py_None) {
p->setfunc = NULL;
- p->restype = &ffi_type_void;
+ p->ffi_restype = &ffi_type_void;
} else {
StgDictObject *dict = PyType_stgdict(restype);
if (dict == NULL || dict->setfunc == NULL) {
@@ -299,7 +392,7 @@
goto error;
}
p->setfunc = dict->setfunc;
- p->restype = &dict->ffi_type_pointer;
+ p->ffi_restype = &dict->ffi_type_pointer;
}
cc = FFI_DEFAULT_ABI;
@@ -323,16 +416,14 @@
goto error;
}
+ Py_INCREF(converters);
p->converters = converters;
+ Py_INCREF(callable);
p->callable = callable;
return p;
error:
- if (p) {
- if (p->pcl)
- FreeClosure(p->pcl);
- PyMem_Free(p);
- }
+ Py_XDECREF(p);
return NULL;
}
Modified: python/trunk/Modules/_ctypes/ctypes.h
==============================================================================
--- python/trunk/Modules/_ctypes/ctypes.h (original)
+++ python/trunk/Modules/_ctypes/ctypes.h Thu Apr 24 20:14:19 2008
@@ -84,14 +84,18 @@
};
typedef struct {
+ PyObject_VAR_HEAD
ffi_closure *pcl; /* the C callable */
ffi_cif cif;
PyObject *converters;
PyObject *callable;
+ PyObject *restype;
SETFUNC setfunc;
- ffi_type *restype;
+ ffi_type *ffi_restype;
ffi_type *atypes[1];
-} ffi_info;
+} CThunkObject;
+extern PyTypeObject CThunk_Type;
+#define CThunk_CheckExact(v) ((v)->ob_type == &CThunk_Type)
typedef struct {
/* First part identical to tagCDataObject */
@@ -107,7 +111,7 @@
union value b_value;
/* end of tagCDataObject, additional fields follow */
- ffi_info *thunk;
+ CThunkObject *thunk;
PyObject *callable;
/* These two fields will override the ones in the type's stgdict if
@@ -178,10 +182,10 @@
extern PyMethodDef module_methods[];
-extern ffi_info *AllocFunctionCallback(PyObject *callable,
- PyObject *converters,
- PyObject *restype,
- int stdcall);
+extern CThunkObject *AllocFunctionCallback(PyObject *callable,
+ PyObject *converters,
+ PyObject *restype,
+ int stdcall);
/* a table entry describing a predefined ctypes type */
struct fielddesc {
char code;
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