Bring in salt.utils.stringio from develop branch

salt/utils/stringio.py

@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+'''
+Functions for StringIO objects
+'''
+
+from __future__ import absolute_import
+
+# Import 3rd-party libs
+from salt.ext import six
+
+# Not using six's fake cStringIO since we need to be able to tell if the object
+# is readable, and this can't be done via what six exposes.
+if six.PY2:
+    import StringIO
+    import cStringIO
+    readable_types = (StringIO.StringIO, cStringIO.InputType)
+    writable_types = (StringIO.StringIO, cStringIO.OutputType)
+else:
+    import io
+    readable_types = (io.StringIO,)
+    writable_types = (io.StringIO,)
+
+
+def is_stringio(obj):
+    return isinstance(obj, readable_types)
+
+
+def is_readable(obj):
+    if six.PY2:
+        return isinstance(obj, readable_types)
+    else:
+        return isinstance(obj, readable_types) and obj.readable()
+
+
+def is_writable(obj):
+    if six.PY2:
+        return isinstance(obj, writable_types)
+    else:
+        return isinstance(obj, writable_types) and obj.writable()