[PEAK] Dispatch on isinstance() for Zope Extension classes

[Alain Poirier]

Le Mardi 28 Mars 2006 17:26, Phillip J. Eby a écrit :
> At 02:46 PM 3/28/2006 +0200, Alain Poirier wrote:
> >Hi Phillip,
> >
> >Using RuleDispatch with Zope 2.x, I've got the problem that the
> >'isinstance()' rule doesn't accept a Zope extension class.
> >
> >Do you think it could be possible to fix this problem ?
>
> You need to define an adapter from ExtensionClass.ExtensionClass (I think
> that's the right type) to dispatch.interfaces.ICriterion.  The adapter
> you should use is dispatch.strategy.ClassCriterion.  Something like:
>
>      protocols.declareAdapter(ClassCriterion, [ICriterion],
> [ExtensionClass])
>
> Let me know if that doesn't fix it for you.

After declaring this adapter, I had :

"""
 ...
 Module dispatch.functions, line 5, in processEvent
 Module dispatch._speedups, line 329, in 
_speedups.BaseDispatcher.__getitem__
 Module dispatch._speedups, line 240, in _speedups.dispatch_by_mro
TypeError: ('Not a class or type:', <extension class 
pjsproduct_zb.pjsproduct.CPJSProduct at b58e4ae8>)
"""


So I tried to patch the speedups.pyx module as below. Now 'instance(o, X)'
seems to work if o is a direct instance of X but not if o is a instance of
a sub-class of X. Need more testing.

Here is where I'am for the moment. Any ideas ? 


"""
--- RuleDispatch-0.5a0/src/dispatch/_speedups.pyx	2005-11-03 
16:57:16.000000000 +0100
+++ RuleDispatch-0.5a0.new/src/dispatch/_speedups.pyx	2006-03-29 
17:02:08.000000000 +0200
@@ -6,6 +6,7 @@
 cdef object InstanceType, NoApplicableMethods, DispatchError, _NF, __nclass
 from dispatch.interfaces import NoApplicableMethods, DispatchError
 from types import InstanceType
+from ExtensionClass import ExtensionClass
 __nclass = "__class__"

 _NF = [0,None, NoApplicableMethods, (None,None)]
@@ -98,11 +99,10 @@
     object __Pyx_GetExcValue()


+cdef extern from "ExtensionClass.h":

-
-
-
-
+    ctypedef struct PyExtensionClass:
+        PyTupleObject *bases



@@ -209,10 +209,10 @@
     cdef int bc
     cdef void *tmp
     cdef PyTupleObject *bases
-
+
     if not PyDict_Check(table):
         raise TypeError("Not a dict subclass", table)
-
+
     tmp = PyObject_GetAttr(ob, __nclass)
     if tmp:
         klass = <object> tmp
@@ -236,6 +236,8 @@
             bases = (<PyClassObject *>klass).cl_bases
         elif PyType_Check(klass):
             bases = (<PyTypeObject *>klass).tp_bases
+        elif (<PyObject *>klass).ob_type == <PyTypeObject *>ExtensionClass:
+            bases = (<PyExtensionClass *>klass).bases
         else:
             raise TypeError("Not a class or type:", klass)
"""