On 04/06/2018 05:24 PM, Eric Blake wrote:
> PyObject_CallObject is powerful, but awkward - we have to wrap
> all arguments into a temporary tuple before using it.
>
> Let python do more of the work by using PyObject_CallFunction
> anywhere that all arguments can be described by a Py_BuildValue()
> format string, instead of creating one-shot arguments ourselves.
> In fact, for our py_config(), this makes it easier to not worry
> about python 2 String vs. python 3 Unicode.
>
> Similarly, PyObject_CallFunctionObjArgs is nicer when we
> already have PyObjects for all parameters (including in py_open(),
> where we can't use a Py_BuildValue() string for converting a
> C int into Py_True or Py_False, but can easily avoid the tuple
> wrapper).
>
> py_zero() is not converted, as it will be changed differently
> to make 'may_trim' an optional callback parameter.
>
> Signed-off-by: Eric Blake
> ---
> plugins/python/python.c | 97
> -
> 1 file changed, 15 insertions(+), 82 deletions(-)
>
> @@ -258,17 +257,8 @@ py_config (const char *key, const char *value)
> /* Other parameters are passed to the Python .config callback. */
> PyErr_Clear ();
>
> -args = PyTuple_New (2);
In fact, this patch is a corner-case bug fix. Here, and in all sorts of
similar places, we are failing to check for args == NULL (unlikely
except on OOM conditions, but still a valid error condition, where we
would presumably have a nice Python error object to report failure with)...
> -#ifdef HAVE_PYSTRING_FROMSTRING
> -PyTuple_SetItem (args, 0, PyString_FromString (key));
...and instead passing NULL on to a function that would crash. We are
likewise not checking for errors here (although such errors should never
be possible).
> -PyTuple_SetItem (args, 1, PyString_FromString (value));
> -#else
> -PyTuple_SetItem (args, 0, PyUnicode_FromString (key));
> -PyTuple_SetItem (args, 1, PyUnicode_FromString (value));
> -#endif
> -r = PyObject_CallObject (fn, args);
> +r = PyObject_CallFunction (fn, "ss", key, value);
The replacement code is not only shorter, it has fewer places to worry
about corner-case boilerplate error checking.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
signature.asc
Description: OpenPGP digital signature
___
Libguestfs mailing list
Libguestfs@redhat.com
https://www.redhat.com/mailman/listinfo/libguestfs
