On Sun, Mar 10, 2013 at 12:13 PM, Tres Seaver <tsea...@palladion.com> wrote:
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>
> On 03/10/2013 11:55 AM, Jim Fulton wrote:
>> On Sun, Mar 10, 2013 at 11:25 AM, Tres Seaver <tsea...@palladion.com>
>> wrote:
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>>>
>>> On 03/10/2013 09:19 AM, Jim Fulton wrote:
>> ...
>>>> I think the fix is pretty straightforward.
>>>>
>>>> In the default __setstate__ provided by Persistent, and when
>>>> loading non-persistent instances:
>>>>
>>>> - On Python 2, ASCII encode unicode attribute names.
>>>>
>>>> - On Python 3, ASCII decode byte attribute names.
>>>>
>>>> The same transformation is necessary when looking up global
>>>> names.
>>>
>>> Hmm, if zodbpickle has to handle the issue for non-persistent
>>> instances and global names, wouldn't it be simpler to make it handle
>>> persistent instances too?
>>
>> No. It can't know when a key is going to be used for a persistent
>> attribute name.
>>
>>> It can examine the stack inside 'load_dict' to figure out that the
>>> context is an instance, right?
>>
>> Ugh. What stack?
>
> The one where the unpickler keeps its work-in-progress?
>
> static int
> load_none(UnpicklerObject *self)
> {
> PDATA_APPEND(self->stack, Py_None, -1);
> return 0;
> }
>
> static int
> load_dict(UnpicklerObject *self)
> {
> PyObject *dict, *key, *value;
> Py_ssize_t i, j, k;
>
> if ((i = marker(self)) < 0)
> return -1;
> j = Py_SIZE(self->stack);
>
> if ((dict = PyDict_New()) == NULL)
> return -1;
>
> for (k = i + 1; k < j; k += 2) {
> key = self->stack->data[k - 1];
> value = self->stack->data[k];
> if (PyDict_SetItem(dict, key, value) < 0) {
> Py_DECREF(dict);
> return -1;
> }
> }
> Pdata_clear(self->stack, i);
> PDATA_PUSH(self->stack, dict, -1);
> return 0;
> }
That won't work for persistent objects.
Persistent state is set by the deserializer, not by the unpickler.
The deserializer calls the unpickler to load the state. It then calls
__setstate__ on the persistent object to set the state. The
serializer doesn't know how to interpret the state, only __setstate__
does.
Jim
--
Jim Fulton
http://www.linkedin.com/in/jimfulton
Jerky is better than bacon! http://zo.pe/Kqm
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