[pitivi] system: Fix detection of Mac and Windows

[Alexandru Băluț <alexbalut src gnome org>]

commit d30f7e003089b5488a75ee4f477c251f164a80ad
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Mon May 2 22:58:26 2016 +0200

    system: Fix detection of Mac and Windows
    
    Differential Revision: https://phabricator.freedesktop.org/D983

 pitivi/application.py  |    4 +-
 pitivi/utils/system.py |   58 ++++++++++++++++++++++++-----------------------
 tests/test_system.py   |    4 +-
 3 files changed, 34 insertions(+), 32 deletions(-)
---
diff --git a/pitivi/application.py b/pitivi/application.py
index e3f8769..b1df9e5 100644
--- a/pitivi/application.py
+++ b/pitivi/application.py
@@ -47,7 +47,7 @@ from pitivi.utils.loggable import Loggable
 from pitivi.utils.misc import path_from_uri
 from pitivi.utils.misc import quote_uri
 from pitivi.utils.proxy import ProxyManager
-from pitivi.utils.system import getSystem
+from pitivi.utils.system import get_system
 from pitivi.utils.threads import ThreadMaster
 from pitivi.utils.timeline import Zoomable
 
@@ -143,7 +143,7 @@ class Pitivi(Gtk.Application, Loggable):
         self.threads = ThreadMaster()
         self.effects = EffectsManager()
         self.proxy_manager = ProxyManager(self)
-        self.system = getSystem()
+        self.system = get_system()
 
         self.project_manager.connect(
             "new-project-loading", self._newProjectLoadingCb)
diff --git a/pitivi/utils/system.py b/pitivi/utils/system.py
index e7eb8b6..00ea12c 100644
--- a/pitivi/utils/system.py
+++ b/pitivi/utils/system.py
@@ -20,6 +20,7 @@ import datetime
 import multiprocessing
 import os
 import resource
+import sys
 
 from gi.repository import GObject
 
@@ -209,6 +210,8 @@ class GnomeSystem(FreedesktopOrgSystem):
 
     def __init__(self):
         FreedesktopOrgSystem.__init__(self)
+
+        import dbus
         self.bus = dbus.Bus(dbus.Bus.TYPE_SESSION)
 
         # connect to gnome sessionmanager
@@ -221,12 +224,6 @@ class GnomeSystem(FreedesktopOrgSystem):
 
         self.connect('update-power-inhibition', self._updatePowerInhibitionCb)
 
-    def screensaver_is_blockable(self):
-        return True
-
-    def sleep_is_blockable(self):
-        return True
-
     def _updatePowerInhibitionCb(self, unused_system):
         # there are two states we want the program to be in, with regards to
         # power saving, the screen saver is inhibited when the viewer is watched.
@@ -271,34 +268,39 @@ class GnomeSystem(FreedesktopOrgSystem):
                 self.debug("already uninhibited")
 
 
-system_ = None
+class DarwinSystem(System):
+
+    """Apple OS X"""
+
+    def __init__(self):
+        System.__init__(self)
+
 
-# attempts to identify the System, import dependencies and overide system_
-if os.name == 'posix':
-    if 'GNOME_DESKTOP_SESSION_ID' in os.environ:
-        try:
-            import dbus
-            system_ = GnomeSystem
-        except:
-            pass
+class WindowsSystem(System):
 
-    if system_ is None:
-        system_ = FreedesktopOrgSystem
-elif os.name == 'nt':
-    pass
-elif os.name == 'mac':
-    pass
+    """Microsoft Windows"""
 
+    def __init__(self):
+        System.__init__(self)
 
-def getSystem():
-    system = None
-    if system_ is not None:
-        system = system_()
 
-    if system is None:
-        system = System()
+def get_system():
+    """
+    Create a System object.
 
-    return system
+    Returns:
+        System: A System object.
+    """
+    if os.name == 'posix':
+        if sys.platform == 'darwin':
+            return DarwinSystem()
+
+        if 'GNOME_DESKTOP_SESSION_ID' in os.environ:
+            return GnomeSystem()
+        return FreedesktopOrgSystem()
+    if os.name == 'nt':
+        return WindowsSystem()
+    return System()
 
 
 class CPUUsageTracker(object):
diff --git a/tests/test_system.py b/tests/test_system.py
index 885792e..3d07e8c 100644
--- a/tests/test_system.py
+++ b/tests/test_system.py
@@ -21,7 +21,7 @@
 # Boston, MA 02110-1301, USA.
 from unittest import TestCase
 
-from pitivi.utils.system import getSystem
+from pitivi.utils.system import get_system
 from pitivi.utils.system import GnomeSystem
 from pitivi.utils.system import INHIBIT_LOGOUT
 from pitivi.utils.system import INHIBIT_SESSION_IDLE
@@ -92,7 +92,7 @@ class TestSystem(TestCase):
 class TestGnomeSystem(TestCase):
 
     def setUp(self):
-        self.system = getSystem()
+        self.system = get_system()
 
     def testPowerInhibition(self):
         if not isinstance(self.system, GnomeSystem):