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gh-87193: Support bytes objects with refcount > 1 in _PyBytes_Resize() (GH-117160)

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Create a new bytes object and destroy the old one if it has refcount > 1.
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Serhiy Storchaka 2024-03-25 17:32:11 +02:00 • committed by GitHub
parent 01e7405da4
commit 0c1a42cf9c
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GPG key ID: B5690EEEBB952194
11 changed files with 123 additions and 30 deletions
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41
Objects/bytesobject.c
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@ -3025,11 +3025,9 @@ PyBytes_ConcatAndDel(PyObject **pv, PyObject *w)
/* The following function breaks the notion that bytes are immutable:
it changes the size of a bytes object. We get away with this only if there
is only one module referencing the object. You can also think of it
it changes the size of a bytes object. You can think of it
as creating a new bytes object and destroying the old one, only
more efficiently. In any case, don't use this if the bytes object may
already be known to some other part of the code...
more efficiently.
Note that if there's not enough memory to resize the bytes object, the
original bytes object at *pv is deallocated, *pv is set to NULL, an "out of
memory" exception is set, and -1 is returned. Else (on success) 0 is
@ -3045,28 +3043,40 @@ _PyBytes_Resize(PyObject **pv, Py_ssize_t newsize)
PyBytesObject *sv;
v = *pv;
if (!PyBytes_Check(v) || newsize < 0) {
goto error;
*pv = 0;
Py_DECREF(v);
PyErr_BadInternalCall();
return -1;
}
if (Py_SIZE(v) == newsize) {
Py_ssize_t oldsize = PyBytes_GET_SIZE(v);
if (oldsize == newsize) {
/* return early if newsize equals to v->ob_size */
return 0;
}
if (Py_SIZE(v) == 0) {
if (newsize == 0) {
return 0;
}
if (oldsize == 0) {
*pv = _PyBytes_FromSize(newsize, 0);
Py_DECREF(v);
return (*pv == NULL) ? -1 : 0;
}
if (Py_REFCNT(v) != 1) {
goto error;
}
if (newsize == 0) {
*pv = bytes_get_empty();
Py_DECREF(v);
return 0;
}
if (Py_REFCNT(v) != 1) {
if (oldsize < newsize) {
*pv = _PyBytes_FromSize(newsize, 0);
if (*pv) {
memcpy(PyBytes_AS_STRING(*pv), PyBytes_AS_STRING(v), oldsize);
}
}
else {
*pv = PyBytes_FromStringAndSize(PyBytes_AS_STRING(v), newsize);
}
Py_DECREF(v);
return (*pv == NULL) ? -1 : 0;
}
#ifdef Py_TRACE_REFS
_Py_ForgetReference(v);
#endif
@ -3089,11 +3099,6 @@ _Py_COMP_DIAG_IGNORE_DEPR_DECLS
sv->ob_shash = -1; /* invalidate cached hash value */
_Py_COMP_DIAG_POP
return 0;
error:
*pv = 0;
Py_DECREF(v);
PyErr_BadInternalCall();
return -1;
}