bpo-39573: Add Py_SET_REFCNT() function (GH-18389)

Add a Py_SET_REFCNT() function to set the reference counter of an
object.
This commit is contained in:
Victor Stinner 2020-02-07 01:24:29 +01:00 committed by GitHub
parent a93c51e3a8
commit c86a11221d
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GPG Key ID: 4AEE18F83AFDEB23
7 changed files with 30 additions and 14 deletions

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@ -79,6 +79,13 @@ the definition of all other Python objects.
(((PyObject*)(o))->ob_refcnt)
.. c:function:: void Py_SET_REFCNT(PyObject *o, Py_ssize_t refcnt)
Set the object *o* reference counter to *refcnt*.
.. versionadded:: 3.9
.. c:macro:: Py_SIZE(o)
This macro is used to access the :attr:`ob_size` member of a Python object.

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@ -123,6 +123,11 @@ typedef struct {
#define Py_TYPE(ob) (_PyObject_CAST(ob)->ob_type)
#define Py_SIZE(ob) (_PyVarObject_CAST(ob)->ob_size)
static inline void _Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) {
ob->ob_refcnt = refcnt;
}
#define Py_SET_REFCNT(ob, refcnt) _Py_SET_REFCNT(_PyObject_CAST(ob), refcnt)
/*
Type objects contain a string containing the type name (to help somewhat
in debugging), the allocation parameters (see PyObject_New() and

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@ -0,0 +1,2 @@
Add a :c:func:`Py_SET_REFCNT` function to set the reference counter of an
object.

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@ -3551,7 +3551,7 @@ slot_tp_del(PyObject *self)
/* Temporarily resurrect the object. */
assert(Py_REFCNT(self) == 0);
Py_REFCNT(self) = 1;
Py_SET_REFCNT(self, 1);
/* Save the current exception, if any. */
PyErr_Fetch(&error_type, &error_value, &error_traceback);
@ -3574,7 +3574,8 @@ slot_tp_del(PyObject *self)
* cause a recursive call.
*/
assert(Py_REFCNT(self) > 0);
if (--Py_REFCNT(self) == 0) {
Py_SET_REFCNT(self, Py_REFCNT(self) - 1);
if (Py_REFCNT(self) == 0) {
/* this is the normal path out */
return;
}
@ -3585,7 +3586,7 @@ slot_tp_del(PyObject *self)
{
Py_ssize_t refcnt = Py_REFCNT(self);
_Py_NewReference(self);
Py_REFCNT(self) = refcnt;
Py_SET_REFCNT(self, refcnt);
}
assert(!PyType_IS_GC(Py_TYPE(self)) || _PyObject_GC_IS_TRACKED(self));
/* If Py_REF_DEBUG macro is defined, _Py_NewReference() increased
@ -4621,7 +4622,7 @@ check_pyobject_uninitialized_is_freed(PyObject *self, PyObject *Py_UNUSED(args))
return NULL;
}
/* Initialize reference count to avoid early crash in ceval or GC */
Py_REFCNT(op) = 1;
Py_SET_REFCNT(op, 1);
/* object fields like ob_type are uninitialized! */
return test_pyobject_is_freed("check_pyobject_uninitialized_is_freed", op);
}
@ -4636,7 +4637,7 @@ check_pyobject_forbidden_bytes_is_freed(PyObject *self, PyObject *Py_UNUSED(args
return NULL;
}
/* Initialize reference count to avoid early crash in ceval or GC */
Py_REFCNT(op) = 1;
Py_SET_REFCNT(op, 1);
/* ob_type field is after the memory block: part of "forbidden bytes"
when using debug hooks on memory allocators! */
return test_pyobject_is_freed("check_pyobject_forbidden_bytes_is_freed", op);
@ -4652,7 +4653,7 @@ check_pyobject_freed_is_freed(PyObject *self, PyObject *Py_UNUSED(args))
}
Py_TYPE(op)->tp_dealloc(op);
/* Reset reference count to avoid early crash in ceval or GC */
Py_REFCNT(op) = 1;
Py_SET_REFCNT(op, 1);
/* object memory is freed! */
return test_pyobject_is_freed("check_pyobject_freed_is_freed", op);
}
@ -5134,7 +5135,7 @@ negative_refcount(PyObject *self, PyObject *Py_UNUSED(args))
}
assert(Py_REFCNT(obj) == 1);
Py_REFCNT(obj) = 0;
Py_SET_REFCNT(obj, 0);
/* Py_DECREF() must call _Py_NegativeRefcount() and abort Python */
Py_DECREF(obj);

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@ -51,7 +51,7 @@ PyModuleDef_Init(struct PyModuleDef* def)
return NULL;
if (def->m_base.m_index == 0) {
max_module_number++;
Py_REFCNT(def) = 1;
Py_SET_REFCNT(def, 1);
Py_TYPE(def) = &PyModuleDef_Type;
def->m_base.m_index = max_module_number;
}

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@ -213,7 +213,7 @@ PyObject_CallFinalizerFromDealloc(PyObject *self)
}
/* Temporarily resurrect the object. */
Py_REFCNT(self) = 1;
Py_SET_REFCNT(self, 1);
PyObject_CallFinalizer(self);
@ -223,7 +223,8 @@ PyObject_CallFinalizerFromDealloc(PyObject *self)
/* Undo the temporary resurrection; can't use DECREF here, it would
* cause a recursive call. */
if (--Py_REFCNT(self) == 0) {
Py_SET_REFCNT(self, Py_REFCNT(self) - 1);
if (Py_REFCNT(self) == 0) {
return 0; /* this is the normal path out */
}
@ -231,7 +232,7 @@ PyObject_CallFinalizerFromDealloc(PyObject *self)
* never happened. */
Py_ssize_t refcnt = Py_REFCNT(self);
_Py_NewReference(self);
Py_REFCNT(self) = refcnt;
Py_SET_REFCNT(self, refcnt);
_PyObject_ASSERT(self,
(!PyType_IS_GC(Py_TYPE(self))
@ -1818,7 +1819,7 @@ _Py_NewReference(PyObject *op)
#ifdef Py_REF_DEBUG
_Py_RefTotal++;
#endif
Py_REFCNT(op) = 1;
Py_SET_REFCNT(op, 1);
#ifdef Py_TRACE_REFS
_Py_AddToAllObjects(op, 1);
#endif

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@ -1903,7 +1903,7 @@ unicode_dealloc(PyObject *unicode)
case SSTATE_INTERNED_MORTAL:
/* revive dead object temporarily for DelItem */
Py_REFCNT(unicode) = 3;
Py_SET_REFCNT(unicode, 3);
if (PyDict_DelItem(interned, unicode) != 0) {
_PyErr_WriteUnraisableMsg("deletion of interned string failed",
NULL);
@ -15367,7 +15367,7 @@ PyUnicode_InternInPlace(PyObject **p)
}
/* The two references in interned are not counted by refcnt.
The deallocator will take care of this */
Py_REFCNT(s) -= 2;
Py_SET_REFCNT(s, Py_REFCNT(s) - 2);
_PyUnicode_STATE(s).interned = SSTATE_INTERNED_MORTAL;
}