[Checkins] SVN: Acquisition/branches/erp5-aq_dynamic/src/Acquisition/ Add _aq_dynamic functionality to Acquisition in the erp5-aq_dynamic branch
Leonardo Rochael Almeida
leorochael at gmail.com
Wed Sep 23 12:03:10 EDT 2009
Log message for revision 104452:
Add _aq_dynamic functionality to Acquisition in the erp5-aq_dynamic branch
Changed:
U Acquisition/branches/erp5-aq_dynamic/src/Acquisition/_Acquisition.c
A Acquisition/branches/erp5-aq_dynamic/src/Acquisition/test_dynamic_acquisition.py
U Acquisition/branches/erp5-aq_dynamic/src/Acquisition/tests.py
-=-
Modified: Acquisition/branches/erp5-aq_dynamic/src/Acquisition/_Acquisition.c
===================================================================
--- Acquisition/branches/erp5-aq_dynamic/src/Acquisition/_Acquisition.c 2009-09-23 15:54:42 UTC (rev 104451)
+++ Acquisition/branches/erp5-aq_dynamic/src/Acquisition/_Acquisition.c 2009-09-23 16:03:09 UTC (rev 104452)
@@ -447,6 +447,64 @@
}
static PyObject *
+Wrapper_GetAttr(PyObject *self, PyObject *attr_name, PyObject *orig)
+{
+ /* This function retrieves an attribute from an object by PyObject_GetAttr.
+
+ The main difference between Wrapper_GetAttr and PyObject_GetAttr is that
+ Wrapper_GetAttr calls _aq_dynamic to generate an attribute dynamically, if
+ the attribute is not found.
+ */
+ PyObject *r, *v, *tb;
+ PyObject *d, *m;
+ PyObject *o;
+
+ if (isWrapper (self))
+ o = WRAPPER(self)->obj;
+ else
+ o = self;
+
+ /* Try to get an attribute in the normal way first. */
+ r = PyObject_GetAttr(o, attr_name);
+ if (r)
+ return r;
+
+ /* If an unexpected error happens, return immediately. */
+ PyErr_Fetch(&r,&v,&tb);
+ if (r != PyExc_AttributeError)
+ {
+ PyErr_Restore(r,v,tb);
+ return NULL;
+ }
+
+ /* Try to get _aq_dynamic. */
+ m = PyObject_GetAttrString(o, "_aq_dynamic");
+ if (! m) {
+ PyErr_Restore(r,v,tb);
+ return NULL;
+ }
+
+ /* Call _aq_dynamic in the context of the original acquisition wrapper. */
+ if (PyECMethod_Check(m) && PyECMethod_Self(m)==o)
+ ASSIGN(m,PyECMethod_New(m,OBJECT(self)));
+ else if (has__of__(m)) ASSIGN(m,__of__(m,OBJECT(self)));
+ d = PyObject_CallFunction(m, "O", attr_name);
+ Py_DECREF(m);
+
+ /* In the case of None, assume that the attribute is not found. */
+ if (d == Py_None) {
+ Py_DECREF(d);
+ PyErr_Restore(r,v,tb);
+ return NULL;
+ }
+
+ Py_XDECREF(r);
+ Py_XDECREF(v);
+ Py_XDECREF(tb);
+ return d;
+}
+
+static PyObject *
Wrapper_acquire(Wrapper *self, PyObject *oname,
PyObject *filter, PyObject *extra, PyObject *orig,
int explicit, int containment);
@@ -544,8 +602,8 @@
Py_XDECREF(r); Py_XDECREF(v); Py_XDECREF(tb);
r=NULL;
}
- /* normal attribute lookup */
- else if ((r=PyObject_GetAttr(self->obj,oname)))
+ /* Give _aq_dynamic a chance, then normal attribute lookup */
+ else if ((r=Wrapper_GetAttr(OBJECT(self),oname,orig)))
{
if (r==Acquired)
{
@@ -669,7 +727,7 @@
Py_XDECREF(r); Py_XDECREF(v); Py_XDECREF(tb);
r=NULL;
- if ((r=PyObject_GetAttr(self->container,oname))) {
+ if ((r=Wrapper_GetAttr(self->container,oname,orig))) {
if (r == Acquired) {
Py_DECREF(r);
}
@@ -706,7 +764,7 @@
Wrapper_getattro(Wrapper *self, PyObject *oname)
{
if (self->obj || self->container)
- return Wrapper_findattr(self, oname, NULL, NULL, NULL, 1, 1, 0, 0);
+ return Wrapper_findattr(self, oname, NULL, NULL, OBJECT(self), 1, 1, 0, 0);
/* Maybe we are getting initialized? */
return Py_FindAttr(OBJECT(self),oname);
@@ -723,7 +781,7 @@
return Py_FindAttr(OBJECT(self),oname);
if (self->obj || self->container)
- return Wrapper_findattr(self, oname, NULL, NULL, NULL, 1, 0, 0, 0);
+ return Wrapper_findattr(self, oname, NULL, NULL, OBJECT(self), 1, 0, 0, 0);
/* Maybe we are getting initialized? */
return Py_FindAttr(OBJECT(self),oname);
Added: Acquisition/branches/erp5-aq_dynamic/src/Acquisition/test_dynamic_acquisition.py
===================================================================
--- Acquisition/branches/erp5-aq_dynamic/src/Acquisition/test_dynamic_acquisition.py (rev 0)
+++ Acquisition/branches/erp5-aq_dynamic/src/Acquisition/test_dynamic_acquisition.py 2009-09-23 16:03:09 UTC (rev 104452)
@@ -0,0 +1,160 @@
+##############################################################################
+#
+# Copyright (c) 1996-2002 Zope Corporation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.0 (ZPL). A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+from ExtensionClass import Base
+import Acquisition
+
+def checkContext(self, o):
+ # Python equivalent to aq_inContextOf
+ from Acquisition import aq_base, aq_parent, aq_inner
+ subob = self
+ o = aq_base(o)
+ while 1:
+ if aq_base(subob) is o:
+ return True
+ self = aq_inner(subob)
+ if self is None: break
+ subob = aq_parent(self)
+ if subob is None: break
+ return False
+
+class B(Acquisition.Implicit):
+ color='red'
+
+ def __init__(self, name='b'):
+ self.name = name
+
+ def _aq_dynamic(self, attr):
+ if attr == 'bonjour': return None
+
+ def dynmethod():
+ chain = ' <- '.join(repr(obj) for obj in Acquisition.aq_chain(self))
+ print repr(self) + '.' + attr
+ print 'chain:', chain
+
+ return dynmethod
+
+ def __repr__(self):
+ return "%s(%r)" % (self.__class__.__name__, self.name)
+
+class A(Acquisition.Implicit):
+
+ def __init__(self, name='a'):
+ self.name = name
+
+ def hi(self):
+ print self, self.color
+
+ def _aq_dynamic(self, attr):
+ return None
+
+ def __repr__(self):
+ return "%s(%r)" % (self.__class__.__name__, self.name)
+
+def test_dynamic():
+ r'''
+ The _aq_dynamic functionality allows an object to dynamically provide an
+ attribute.
+
+ If an object doesn't have an attribute, Acquisition checks to see if the
+ object has a _aq_dynamic method, which is then called. It is functionally
+ equivalent to __getattr__, but _aq_dynamic is called with 'self' as the
+ acquisition wrapped object where as __getattr__ is called with self as the
+ unwrapped object.
+
+ Let's see how this works. In the examples below, the A class defines
+ '_aq_dynamic', but returns 'None' for all attempts, which means that no new
+ attributes should be generated dynamically. It also doesn't define 'color'
+ attribute, even though it uses it in the 'hi' method.
+
+ >>> A().hi()
+ Traceback (most recent call last):
+ ...
+ AttributeError: color
+
+ The class B, on the other hand, generates all attributes dynamically,
+ except if it is called 'bonjour'.
+
+ First we need to check that, even if an object provides '_aq_dynamic',
+ "regular" Aquisition attribute access should still work:
+
+ >>> b=B()
+ >>> b.a=A()
+ >>> b.a.hi()
+ A('a') red
+ >>> b.a.color='green'
+ >>> b.a.hi()
+ A('a') green
+
+ Now, let's see some dynamically generated action. B does not define a
+ 'salut' method, but remember that it dynamically generates a method for
+ every attribute access:
+
+ >>> b.a.salut()
+ B('b').salut
+ chain: B('b')
+
+ >>> a=A('a1')
+ >>> a.b=B('b1')
+ >>> a.b.salut()
+ B('b1').salut
+ chain: B('b1') <- A('a1')
+
+ >>> b.a.bonjour()
+ Traceback (most recent call last):
+ ...
+ AttributeError: bonjour
+
+ >>> a.b.bonjour()
+ Traceback (most recent call last):
+ ...
+ AttributeError: bonjour
+
+ '''
+
+def test_wrapper_comparissons():
+ r'''
+
+ Test wrapper comparisons in presence of _aq_dynamic
+
+ >>> b=B()
+ >>> b.a=A()
+ >>> foo = b.a
+ >>> bar = b.a
+ >>> assert( foo == bar )
+ >>> c = A('c')
+ >>> b.c = c
+ >>> b.c.d = c
+ >>> b.c.d == c
+ True
+ >>> b.c.d == b.c
+ True
+ >>> b.c == c
+ True
+
+ Test contextuality in presence of _aq_dynamic
+
+ >>> checkContext(b.c, b)
+ True
+ >>> checkContext(b.c, b.a)
+ False
+
+ >>> assert b.a.aq_inContextOf(b)
+ >>> assert b.c.aq_inContextOf(b)
+ >>> assert b.c.d.aq_inContextOf(b)
+ >>> assert b.c.d.aq_inContextOf(c)
+ >>> assert b.c.d.aq_inContextOf(b.c)
+ >>> assert not b.c.aq_inContextOf(foo)
+ >>> assert not b.c.aq_inContextOf(b.a)
+ >>> assert not b.a.aq_inContextOf('somestring')
+'''
Modified: Acquisition/branches/erp5-aq_dynamic/src/Acquisition/tests.py
===================================================================
--- Acquisition/branches/erp5-aq_dynamic/src/Acquisition/tests.py 2009-09-23 15:54:42 UTC (rev 104451)
+++ Acquisition/branches/erp5-aq_dynamic/src/Acquisition/tests.py 2009-09-23 16:03:09 UTC (rev 104452)
@@ -2270,6 +2270,7 @@
def test_suite():
return unittest.TestSuite((
DocTestSuite(),
+ DocTestSuite('Acquisition.test_dynamic_acquisition'),
DocFileSuite('README.txt', package='Acquisition'),
))
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