[master 1/3] Add an abstract parent of all filesystem tasks.

[dashea]

From: mulhern

It defines the initializer, which should not vary among filesystem tasks.

Include a convenience class for simple unimplemented filesystem tasks.

Signed-off-by: mulhern 
---
 blivet/tasks/fstask.py | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 blivet/tasks/fstask.py

diff --git a/blivet/tasks/fstask.py b/blivet/tasks/fstask.py
new file mode 100644
index 0000000..46dc3d6
--- /dev/null
+++ b/blivet/tasks/fstask.py
@@ -0,0 +1,47 @@
+# fstask.py
+# Superclass for filesystem tasks.
+#
+# Copyright (C) 2015  Red Hat, Inc.
+#
+# This copyrighted material is made available to anyone wishing to use,
+# modify, copy, or redistribute it subject to the terms and conditions of
+# the GNU General Public License v.2, or (at your option) any later version.
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY expressed or implied, including the implied warranties of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+# Public License for more details.  You should have received a copy of the
+# GNU General Public License along with this program; if not, write to the
+# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.  Any Red Hat trademarks that are incorporated in the
+# source code or documentation are not subject to the GNU General Public
+# License and may only be used or replicated with the express permission of
+# Red Hat, Inc.
+#
+# Red Hat Author(s): Anne Mulhern 
+
+import abc
+
+from six import add_metaclass
+
+from . import task
+
+@add_metaclass(abc.ABCMeta)
+class FSTask(task.Task):
+    """ An abstract class that encapsulates the fact that all FSTasks
+        have a single master object: the filesystem that they belong to.
+    """
+    description = "parent of all filesystem tasks"
+
+    def __init__(self, an_fs):
+        """ Initializer.
+
+            :param FS an_fs: a filesystem object
+        """
+        self.fs = an_fs
+
+class UnimplementedFSTask(FSTask, task.UnimplementedTask):
+    """ A convenience class for unimplemented filesystem tasks.
+        Useful in the usual case where an Unimplemented task has
+        no special methods that it is required to implement.
+    """
+    pass