Bind connection close callback APIs to python binding

Add code in the python binding to cope with the new APIs
virConnectRegisterCloseCallback and
virConnectUnregisterCloseCallback. Also demonstrate their
use in the python domain events demo

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

generator.py

@@ -425,8 +425,6 @@ skip_impl = (
     'virDomainGetInterfaceParameters',
     'virDomainGetCPUStats',
     'virDomainGetDiskErrors',
-    'virConnectUnregisterCloseCallback',
-    'virConnectRegisterCloseCallback',
     'virNodeGetMemoryParameters',
     'virNodeSetMemoryParameters',
     'virNodeGetCPUMap',
@@ -476,6 +474,9 @@ skip_function = (
     'virStreamRecv', # overridden in libvirt-override-virStream.py
     'virStreamSend', # overridden in libvirt-override-virStream.py
 
+    'virConnectUnregisterCloseCallback', # overriden in virConnect.py
+    'virConnectRegisterCloseCallback', # overriden in virConnect.py
+
     # 'Ref' functions have no use for bindings users.
     "virConnectRef",
     "virDomainRef",

libvirt-override-virConnect.py

@@ -287,3 +287,26 @@
             retlist.append(virSecret(self, _obj=secret_ptr))
 
         return retlist
+
+    def _dispatchCloseCallback(self, reason, cbData):
+        """Dispatches events to python user close callback"""
+        cb = cbData["cb"]
+        opaque = cbData["opaque"]
+
+        cb(self, reason, opaque)
+        return 0
+
+
+    def unregisterCloseCallback(self):
+        """Removes a close event callback"""
+        ret = libvirtmod.virConnectUnregisterCloseCallback(self._o)
+        if ret == -1: raise libvirtError ('virConnectUnregisterCloseCallback() failed', conn=self)
+
+    def registerCloseCallback(self, cb, opaque):
+        """Adds a close event callback, providing a notification
+         when a connection fails / closes"""
+        cbData = { "cb": cb, "conn": self, "opaque": opaque }
+        ret = libvirtmod.virConnectRegisterCloseCallback(self._o, cbData)
+        if ret == -1:
+            raise libvirtError ('virConnectRegisterCloseCallback() failed', conn=self)
+        return ret

libvirt-override.c

@@ -6001,6 +6001,111 @@ libvirt_virConnectDomainEventDeregisterAny(ATTRIBUTE_UNUSED PyObject * self,
     return py_retval;
 }
 
+
+static void
+libvirt_virConnectCloseCallbackDispatch(virConnectPtr conn ATTRIBUTE_UNUSED,
+                                        int reason,
+                                        void *opaque)
+{
+    PyObject *pyobj_cbData = (PyObject*)opaque;
+    PyObject *pyobj_ret;
+    PyObject *pyobj_conn;
+    PyObject *dictKey;
+
+    LIBVIRT_ENSURE_THREAD_STATE;
+
+    Py_INCREF(pyobj_cbData);
+
+    dictKey = libvirt_constcharPtrWrap("conn");
+    pyobj_conn = PyDict_GetItem(pyobj_cbData, dictKey);
+    Py_DECREF(dictKey);
+
+    /* Call the Callback Dispatcher */
+    pyobj_ret = PyObject_CallMethod(pyobj_conn,
+                                    (char*)"_dispatchCloseCallback",
+                                    (char*)"iO",
+                                    reason,
+                                    pyobj_cbData);
+
+    Py_DECREF(pyobj_cbData);
+
+    if(!pyobj_ret) {
+        DEBUG("%s - ret:%p\n", __FUNCTION__, pyobj_ret);
+        PyErr_Print();
+    } else {
+        Py_DECREF(pyobj_ret);
+    }
+
+    LIBVIRT_RELEASE_THREAD_STATE;
+}
+
+static PyObject *
+libvirt_virConnectRegisterCloseCallback(ATTRIBUTE_UNUSED PyObject * self,
+                                        PyObject * args)
+{
+    PyObject *py_retval;        /* return value */
+    PyObject *pyobj_conn;       /* virConnectPtr */
+    PyObject *pyobj_cbData;     /* hash of callback data */
+    virConnectPtr conn;
+    int ret = 0;
+
+    if (!PyArg_ParseTuple
+        (args, (char *) "OO:virConnectRegisterCloseCallback",
+         &pyobj_conn, &pyobj_cbData)) {
+        DEBUG("%s failed parsing tuple\n", __FUNCTION__);
+        return VIR_PY_INT_FAIL;
+    }
+
+    DEBUG("libvirt_virConnectRegisterCloseCallback(%p %p) called\n",
+           pyobj_conn, pyobj_cbData);
+    conn = PyvirConnect_Get(pyobj_conn);
+
+    Py_INCREF(pyobj_cbData);
+
+    LIBVIRT_BEGIN_ALLOW_THREADS;
+    ret = virConnectRegisterCloseCallback(conn,
+                                          libvirt_virConnectCloseCallbackDispatch,
+                                          pyobj_cbData,
+                                          libvirt_virConnectDomainEventFreeFunc);
+    LIBVIRT_END_ALLOW_THREADS;
+
+    if (ret < 0) {
+        Py_DECREF(pyobj_cbData);
+    }
+
+    py_retval = libvirt_intWrap(ret);
+    return py_retval;
+}
+
+static PyObject *
+libvirt_virConnectUnregisterCloseCallback(ATTRIBUTE_UNUSED PyObject * self,
+                                          PyObject * args)
+{
+    PyObject *py_retval;
+    PyObject *pyobj_conn;
+    virConnectPtr conn;
+    int ret = 0;
+
+    if (!PyArg_ParseTuple
+        (args, (char *) "O:virConnectDomainEventUnregister",
+         &pyobj_conn))
+        return NULL;
+
+    DEBUG("libvirt_virConnectDomainEventUnregister(%p) called\n",
+          pyobj_conn);
+
+    conn = PyvirConnect_Get(pyobj_conn);
+
+    LIBVIRT_BEGIN_ALLOW_THREADS;
+
+    ret = virConnectUnregisterCloseCallback(conn,
+                                            libvirt_virConnectCloseCallbackDispatch);
+
+    LIBVIRT_END_ALLOW_THREADS;
+    py_retval = libvirt_intWrap(ret);
+    return py_retval;
+}
+
 static void
 libvirt_virStreamEventFreeFunc(void *opaque)
 {
@@ -6502,6 +6607,8 @@ static PyMethodDef libvirtMethods[] = {
     {(char *) "virConnectDomainEventDeregister", libvirt_virConnectDomainEventDeregister, METH_VARARGS, NULL},
     {(char *) "virConnectDomainEventRegisterAny", libvirt_virConnectDomainEventRegisterAny, METH_VARARGS, NULL},
     {(char *) "virConnectDomainEventDeregisterAny", libvirt_virConnectDomainEventDeregisterAny, METH_VARARGS, NULL},
+    {(char *) "virConnectRegisterCloseCallback", libvirt_virConnectRegisterCloseCallback, METH_VARARGS, NULL},
+    {(char *) "virConnectUnregisterCloseCallback", libvirt_virConnectUnregisterCloseCallback, METH_VARARGS, NULL},
     {(char *) "virStreamEventAddCallback", libvirt_virStreamEventAddCallback, METH_VARARGS, NULL},
     {(char *) "virStreamRecv", libvirt_virStreamRecv, METH_VARARGS, NULL},
     {(char *) "virStreamSend", libvirt_virStreamSend, METH_VARARGS, NULL},