[master 1/30] Add an abstract Task class w/ a couple of necessary methods.

mulkieran installerbot-noreply at redhat.com
Wed Mar 25 22:47:39 UTC 2015


From: mulhern <amulhern at redhat.com>

Signed-off-by: mulhern <amulhern at redhat.com>
---
 blivet/tasks/task.py | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 blivet/tasks/task.py

diff --git a/blivet/tasks/task.py b/blivet/tasks/task.py
new file mode 100644
index 0000000..d63fb1c
--- /dev/null
+++ b/blivet/tasks/task.py
@@ -0,0 +1,63 @@
+# task.py
+# Abstract class for 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 <amulhern at redhat.com>
+
+import abc
+
+from six import add_metaclass
+
+ at add_metaclass(abc.ABCMeta)
+class Task(object):
+    """ An abstract class that represents some task. """
+
+    @classmethod
+    @abc.abstractmethod
+    def available(cls):
+        """ A class-level method indicating whether tasks of this class
+            are available.
+        """
+        raise NotImplementedError()
+
+    description = abc.abstractproperty(doc="Brief description for this task.")
+
+    # Note that unavailable is able to obtain more precise information than
+    # available, since it is able to access the filesystem object.
+    unavailable = abc.abstractproperty(
+       doc="Reason if the necessary external tools are unavailable.")
+
+    unready = abc.abstractproperty(
+       doc="Reason if the external resource is not ready for this action.")
+
+    unable = abc.abstractproperty(
+       doc="Reason if the object is not in a correct state for this task.")
+
+    @property
+    def impossible(self):
+        """ Returns a reason if the task can not succeed, otherwise False.
+
+            :returns: reason or False
+            :rtype: str or bool
+        """
+        return self.unavailable or self.unable or self.unready
+
+    @abc.abstractmethod
+    def doTask(self, *args, **kwargs):
+        """ Do the task for this class. """
+        raise NotImplementedError()


-- 
To view this commit on github, visit https://github.com/rhinstaller/blivet/commit/2009a831913ca1b217395502ae5245a712f3625b


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