support: add is_libvirt_error_no_domain

Repurpose the generic util.exception_is_libvirt_error for the one
purpose that it's actually used, add it as a SupportCache staticmethod,
and test it

tests/xmlconfig.py

@@ -228,3 +228,10 @@ class TestXMLMisc(unittest.TestCase):
         randommac = virtinst.DeviceInterface.generate_mac(realconn)
         self.assertTrue(randommac != testmac)
         self.assertTrue(len(randommac) == len(testmac))
+
+    def test_support_misc(self):
+        try:
+            self.conn.lookupByName("foobar-idontexist")
+        except Exception as e:
+            if not self.conn.support.is_libvirt_error_no_domain(e):
+                raise

virtManager/domain.py

@@ -14,7 +14,6 @@ import libvirt
 from virtinst import DomainCapabilities
 from virtinst import DomainSnapshot
 from virtinst import Guest
-from virtinst import util
 from virtinst import DeviceController
 from virtinst import DeviceDisk
 
@@ -1343,10 +1342,10 @@ class vmmDomain(vmmLibvirtObject):
         if self._has_managed_save is None:
             try:
                 self._has_managed_save = self._backend.hasManagedSaveImage(0)
-            except libvirt.libvirtError as e:
-                if not util.exception_is_libvirt_error(e, "VIR_ERR_NO_DOMAIN"):
-                    raise
+            except Exception as e:
+                if self.conn.support.is_libvirt_error_no_domain(e):
                     return False
+                raise
 
         return self._has_managed_save
 

virtManager/manager.py

@@ -11,8 +11,6 @@ from gi.repository import Gtk
 from gi.repository import Gdk
 from gi.repository import GdkPixbuf
 
-import libvirt
-
 from virtinst import util
 
 from . import vmmenu
@@ -704,8 +702,8 @@ class vmmManager(vmmGObjectUI):
 
             desc = vm.get_description()
             row[ROW_HINT] = util.xml_escape(desc)
-        except libvirt.libvirtError as e:
-            if util.exception_is_libvirt_error(e, "VIR_ERR_NO_DOMAIN"):
+        except Exception as e:
+            if vm.conn.support.is_libvirt_error_no_domain(e):
                 return
             raise
 

virtManager/vmwindow.py

@@ -9,10 +9,6 @@ import logging
 from gi.repository import Gdk
 from gi.repository import Gtk
 
-import libvirt
-
-from virtinst import util
-
 from . import vmmenu
 from .baseclass import vmmGObjectUI
 from .details import vmmDetails
@@ -561,8 +557,8 @@ class vmmVMWindow(vmmGObjectUI):
         try:
             if self.is_visible():
                 self.vm.ensure_latest_xml()
-        except libvirt.libvirtError as e:
-            if util.exception_is_libvirt_error(e, "VIR_ERR_NO_DOMAIN"):
+        except Exception as e:
+            if self.conn.support.is_libvirt_error_no_domain(e):
                 self.close()
                 return
             raise

virtinst/support.py

@@ -235,6 +235,18 @@ class SupportCache:
     Class containing all support checks and access APIs, and support for
     caching returned results
     """
+
+    @staticmethod
+    def is_libvirt_error_no_domain(err):
+        """
+        Small helper to check if the passed exception is a libvirt error
+        with code VIR_ERR_NO_DOMAIN
+        """
+        if not isinstance(err, libvirt.libvirtError):
+            return False
+        return err.get_error_code() == libvirt.VIR_ERR_NO_DOMAIN
+
+
     def __init__(self, virtconn):
         self._cache = {}
         self._virtconn = virtconn

virtinst/util.py

@@ -137,11 +137,6 @@ def is_error_nosupport(err):
     return False
 
 
-def exception_is_libvirt_error(e, error):
-    return (hasattr(libvirt, error) and
-            e.get_error_code() == getattr(libvirt, error))
-
-
 def local_libvirt_version():
     """
     Lookup the local libvirt library version, but cache the value since