about: Convert to singleton

virtManager/about.py

@@ -24,6 +24,18 @@ from .baseclass import vmmGObjectUI
 
 
 class vmmAbout(vmmGObjectUI):
+    _instance = None
+
+    @classmethod
+    def show_instance(cls, parentobj):
+        try:
+            if not cls._instance:
+                cls._instance = cls()
+            cls._instance.show(parentobj.topwin)
+        except Exception as e:
+            parentobj.err.show_err(
+                    _("Error launching 'About' dialog: %s") % str(e))
+
     def __init__(self):
         vmmGObjectUI.__init__(self, "about.ui", "vmm-about")
 
@@ -32,9 +44,10 @@ class vmmAbout(vmmGObjectUI):
             "on_vmm_about_response": self.close,
         })
 
-    def show(self):
+    def show(self, parent):
         logging.debug("Showing about")
         self.topwin.set_version(self.config.get_appversion())
+        self.topwin.set_transient_for(parent)
         self.topwin.present()
 
     def close(self, ignore1=None, ignore2=None):

virtManager/engine.py

@@ -30,7 +30,6 @@ from gi.repository import GObject
 from gi.repository import Gtk
 
 from . import packageutils
-from .about import vmmAbout
 from .baseclass import vmmGObject
 from .clone import vmmCloneVM
 from .connect import vmmConnect
@@ -71,7 +70,6 @@ class vmmEngine(vmmGObject):
 
         self.windowConnect = None
         self.windowPreferences = None
-        self.windowAbout = None
         self.windowCreate = None
         self.windowManager = None
         self.windowMigrate = None
@@ -418,10 +416,6 @@ class vmmEngine(vmmGObject):
             self.windowPreferences.cleanup()
             self.windowPreferences = None
 
-        if self.windowAbout:
-            self.windowAbout.cleanup()
-            self.windowAbout = None
-
         if self.windowConnect:
             self.windowConnect.cleanup()
             self.windowConnect = None
@@ -689,14 +683,6 @@ class vmmEngine(vmmGObject):
     # Dialog launchers #
     ####################
 
-    def _do_show_about(self, src):
-        try:
-            if self.windowAbout is None:
-                self.windowAbout = vmmAbout()
-            self.windowAbout.show()
-        except Exception as e:
-            src.err.show_err(_("Error launching 'About' dialog: %s") % str(e))
-
     def _get_preferences(self):
         if self.windowPreferences:
             return self.windowPreferences
@@ -818,7 +804,6 @@ class vmmEngine(vmmGObject):
         obj.connect("action-show-domain", self._do_show_vm)
         obj.connect("action-show-preferences", self._do_show_preferences)
         obj.connect("action-show-create", self._do_show_create)
-        obj.connect("action-show-about", self._do_show_about)
         obj.connect("action-show-host", self._do_show_host)
         obj.connect("action-show-connect", self._do_show_connect)
         obj.connect("action-exit-app", self.exit_app)

virtManager/manager.py

@@ -92,7 +92,6 @@ class vmmManager(vmmGObjectUI):
     __gsignals__ = {
         "action-show-connect": (GObject.SignalFlags.RUN_FIRST, None, []),
         "action-show-domain": (GObject.SignalFlags.RUN_FIRST, None, [str, str]),
-        "action-show-about": (GObject.SignalFlags.RUN_FIRST, None, []),
         "action-show-host": (GObject.SignalFlags.RUN_FIRST, None, [str]),
         "action-show-preferences": (GObject.SignalFlags.RUN_FIRST, None, []),
         "action-show-create": (GObject.SignalFlags.RUN_FIRST, None, [str]),
@@ -469,8 +468,9 @@ class vmmManager(vmmGObjectUI):
     def new_vm(self, src_ignore=None):
         self.emit("action-show-create", self.current_conn_uri())
 
-    def show_about(self, src_ignore):
-        self.emit("action-show-about")
+    def show_about(self, _src):
+        from .about import vmmAbout
+        vmmAbout.show_instance(self)
 
     def show_preferences(self, src_ignore):
         self.emit("action-show-preferences")