1 files changed, 41 insertions, 0 deletions
diff --git a/cloudinit/mergers/list.py b/cloudinit/mergers/list.py
new file mode 100644
index 00000000..ad1b9793
--- /dev/null
+++ b/cloudinit/mergers/list.py
@@ -0,0 +1,41 @@
+# vi: ts=4 expandtab
+#
+#    Copyright (C) 2012 Yahoo! Inc.
+#
+#    Author: Joshua Harlow <harlowja@yahoo-inc.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License version 3, as
+#    published by the Free Software Foundation.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty 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, see <http://www.gnu.org/licenses/>.
+
+
+class Merger(object):
+    def __init__(self, merger):
+        self._merger = merger
+
+    def _on_tuple(self, value, merge_with):
+        return self._on_list(list(value), merge_with)
+
+    def _on_list(self, value, merge_with):
+        if isinstance(merge_with, (tuple, list)):
+            new_value = list(value)
+            for m_v in merge_with:
+                m_am = 0
+                for (i, o_v) in enumerate(new_value):
+                    if m_v == o_v:
+                        new_value[i] = self._merger.merge(o_v, m_v)
+                        m_am += 1
+                if m_am == 0:
+                    new_value.append(m_v)
+        else:
+            new_value = list(value)
+            new_value.append(merge_with)
+        return new_value