[libvirt] [PATCH python] Fix use of virDomainEventRegister in python bindings

[Daniel P. Berrange]

From: "Daniel P. Berrange" <berrange at redhat.com>

If an app used the virDomainEventRegister binding instead
of the virDomainEventRegisterAny binding, it would never
have its callback invoked. This is because the code for
dispatching from the C libvirt_virConnectDomainEventCallback
method was totally fubar.

If DEBUG macro was set in the python build the error would
become visible

  "libvirt_virConnectDomainEventCallback dom_class is not a class!"

The code in libvirt_virConnectDomainEventCallback was
inexplicably complex and has apparently never worked. The
fix is to write it the same way as the other callback handlers.

Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
 libvirt-override-virConnect.py |  2 +-
 libvirt-override.c             | 64 ++++--------------------------------------
 2 files changed, 6 insertions(+), 60 deletions(-)

diff --git a/libvirt-override-virConnect.py b/libvirt-override-virConnect.py
index 23fadfd..0beaf9c 100644
--- a/libvirt-override-virConnect.py
+++ b/libvirt-override-virConnect.py
@@ -38,7 +38,7 @@
         """
         try:
             for cb,opaque in self.domainEventCallbacks.items():
-                cb(self,dom,event,detail,opaque)
+                cb(self, virDomain(self, _obj=dom), event, detail, opaque)
             return 0
         except AttributeError:
             pass
diff --git a/libvirt-override.c b/libvirt-override.c
index 93b9c5f..5deb414 100644
--- a/libvirt-override.c
+++ b/libvirt-override.c
@@ -4923,7 +4923,6 @@ cleanup:
  *******************************************/
 static PyObject *libvirt_module    = NULL;
 static PyObject *libvirt_dict      = NULL;
-static PyObject *libvirt_dom_class = NULL;
 
 static PyObject *
 getLibvirtModuleObject(void) {
@@ -4959,23 +4958,6 @@ getLibvirtDictObject(void) {
     return libvirt_dict;
 }
 
-static PyObject *
-getLibvirtDomainClassObject(void) {
-    if (libvirt_dom_class)
-        return libvirt_dom_class;
-
-    // PyDict_GetItemString returns a borrowed reference
-    libvirt_dom_class = PyDict_GetItemString(getLibvirtDictObject(),
-                                             "virDomain");
-    if (!libvirt_dom_class) {
-        DEBUG("%s Error importing virDomain class\n", __FUNCTION__);
-        PyErr_Print();
-        return NULL;
-    }
-
-    Py_INCREF(libvirt_dom_class);
-    return libvirt_dom_class;
-}
 
 static PyObject *
 libvirt_lookupPythonFunc(const char *funcname)
@@ -5013,13 +4995,9 @@ libvirt_virConnectDomainEventCallback(virConnectPtr conn ATTRIBUTE_UNUSED,
 {
     PyObject *pyobj_ret;
 
-    PyObject *pyobj_conn_inst = (PyObject*)opaque;
+    PyObject *pyobj_conn = (PyObject*)opaque;
     PyObject *pyobj_dom;
 
-    PyObject *pyobj_dom_args;
-    PyObject *pyobj_dom_inst;
-
-    PyObject *dom_class;
     int ret = -1;
 
     LIBVIRT_ENSURE_THREAD_STATE;
@@ -5027,45 +5005,15 @@ libvirt_virConnectDomainEventCallback(virConnectPtr conn ATTRIBUTE_UNUSED,
     /* Create a python instance of this virDomainPtr */
     virDomainRef(dom);
     pyobj_dom = libvirt_virDomainPtrWrap(dom);
-    pyobj_dom_args = PyTuple_New(2);
-    if (PyTuple_SetItem(pyobj_dom_args, 0, pyobj_conn_inst) != 0) {
-        DEBUG("%s error creating tuple", __FUNCTION__);
-        goto cleanup;
-    }
-    if (PyTuple_SetItem(pyobj_dom_args, 1, pyobj_dom) != 0) {
-        DEBUG("%s error creating tuple", __FUNCTION__);
-        goto cleanup;
-    }
-    Py_INCREF(pyobj_conn_inst);
-
-    dom_class = getLibvirtDomainClassObject();
-    if (!PyClass_Check(dom_class)) {
-        DEBUG("%s dom_class is not a class!\n", __FUNCTION__);
-        goto cleanup;
-    }
-
-    pyobj_dom_inst = PyInstance_New(dom_class,
-                                    pyobj_dom_args,
-                                    NULL);
-
-    Py_DECREF(pyobj_dom_args);
-
-    if (!pyobj_dom_inst) {
-        DEBUG("%s Error creating a python instance of virDomain\n",
-              __FUNCTION__);
-        PyErr_Print();
-        goto cleanup;
-    }
 
     /* Call the Callback Dispatcher */
-    pyobj_ret = PyObject_CallMethod(pyobj_conn_inst,
+    pyobj_ret = PyObject_CallMethod(pyobj_conn,
                                     (char*)"_dispatchDomainEventCallbacks",
                                     (char*)"Oii",
-                                    pyobj_dom_inst,
-                                    event,
-                                    detail);
+                                    pyobj_dom,
+                                    event, detail);
 
-    Py_DECREF(pyobj_dom_inst);
+    Py_DECREF(pyobj_dom);
 
     if (!pyobj_ret) {
         DEBUG("%s - ret:%p\n", __FUNCTION__, pyobj_ret);
@@ -5075,8 +5023,6 @@ libvirt_virConnectDomainEventCallback(virConnectPtr conn ATTRIBUTE_UNUSED,
         ret = 0;
     }
 
-
-cleanup:
     LIBVIRT_RELEASE_THREAD_STATE;
     return ret;
 }
-- 
1.8.3.1