Replace use of ``PyCObject`` APIs with equivalent ``PyCapsule`` APIs,

except under Python 2.6.
    
  N.B.  This change is an ABI incompatibility under Python 2.7:
        extensions built under Python 2.7 against 4.0.x versions of
        ``zope.proxy`` must be rebuilt.
  
Bump target version to '4.1.0' to signal BBB issue.

Enable compilation of dependent modules under Py3k.

CHANGES.txt

@@ -2,10 +2,17 @@
 CHANGES
 =======
 
-4.0.2 (unreleased)
+4.1.0 (unreleased)
 ------------------
 
-- TBD
+- Enabled compilation of dependent modules under Py3k.
+
+- Replaced use of ``PyCObject`` APIs with equivalent ``PyCapsule`` APIs,
+  except under Python 2.6.
+  
+  N.B.  This change is an ABI incompatibility under Python 2.7:
+        extensions built under Python 2.7 against 4.0.x versions of
+        ``zope.proxy`` must be rebuilt.
 
 4.0.1 (2012-11-21)
 ------------------

setup.py

@@ -47,7 +47,7 @@ else:
     features = {'Cwrapper': Cwrapper}
 
 setup(name='zope.proxy',
-      version = '4.0.2dev',
+      version = '4.1.0dev',
       author='Zope Foundation and Contributors',
       author_email='zope-dev@zope.org',
       description='Generic Transparent Proxies',

src/zope/proxy/_zope_proxy_proxy.c

@@ -38,6 +38,11 @@ static PyObject *
 empty_tuple = NULL;
 
 
+#if PY_VERSION_HEX <  0x02070000
+  #define PyCapsule_New(pointer, name, destr) \
+          PyCObject_FromVoidPtr(pointer, destr)
+#endif
+
 // Compatibility with Python 2
 #if PY_MAJOR_VERSION < 3
   #define IS_STRING PyString_Check
@@ -53,9 +58,6 @@ empty_tuple = NULL;
   #define MOD_DEF(ob, name, doc, methods) \
           ob = Py_InitModule3(name, methods, doc);
 
-  #define PyCapsule_New(pointer, name, destr) \
-          PyCObject_FromVoidPtr(pointer, destr)
-
 #else
 
   #define IS_STRING PyUnicode_Check

src/zope/proxy/proxy.h

@@ -15,7 +15,6 @@ typedef struct {
     PyObject *(*getobject)(PyObject *proxy);
 } ProxyInterface;
 
-
 #ifndef PROXY_MODULE
 
 /* These are only defined in the public interface, and are not
@@ -33,9 +32,15 @@ Proxy_Import(void)
         if (m != NULL) {
             PyObject *tmp = PyObject_GetAttrString(m, "_CAPI");
             if (tmp != NULL) {
+#if PY_VERSION_HEX <  0x02070000
                 if (PyCObject_Check(tmp))
                     _proxy_api = (ProxyInterface *)
                         PyCObject_AsVoidPtr(tmp);
+#else
+                if (PyCapsule_CheckExact(tmp))
+                    _proxy_api = (ProxyInterface *)
+                        PyCapsule_GetPointer(tmp, NULL);
+#endif
                 Py_DECREF(tmp);
             }
         }