Add from_utf8_or_none and tests.

[tahoe-lafs/tahoe-lafs.git] / src / allmydata / util / encodingutil.py

diff --git a/src/allmydata/util/encodingutil.py b/src/allmydata/util/encodingutil.py
index feafd8f5c46e6470981c68e14922e1b223af99c2..d14b08f6be448782a454fefd1da22d6d8e9e45eb 100644 (file)
--- a/src/allmydata/util/encodingutil.py
+++ b/src/allmydata/util/encodingutil.py
@@ -3,12 +3,11 @@ Functions used to convert inputs from whatever encoding used in the system to
 unicode and back.
 """
 
-import sys
-import os
-import re
+import sys, os, re, locale
+from types import NoneType
+
 from allmydata.util.assertutil import precondition
 from twisted.python import usage
-import locale
 from allmydata.util import log
 from allmydata.util.fileutil import abspath_expanduser_unicode
 
@@ -127,6 +126,12 @@ def to_str(s):
         return s
     return s.encode('utf-8')
 
+def from_utf8_or_none(s):
+    precondition(isinstance(s, (NoneType, str)), s)
+    if s is None:
+        return s
+    return s.decode('utf-8')
+
 PRINTABLE_ASCII = re.compile(r'^[\n\r\x20-\x7E]*$',          re.DOTALL)
 PRINTABLE_8BIT  = re.compile(r'^[\n\r\x20-\x7E\x80-\xFF]*$', re.DOTALL)