improve unicode support

recipe_engine/step_runner.py

 # Copyright 2016 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
-import cStringIO
+import StringIO
 import collections
 import contextlib
 import datetime
 import json
 import os
 import re
 import sys
 import time
 import tempfile
 import traceback
@@ skipping 22 matching lines @@
   # ).
   #
   # For more information, see:
   # https://msdn.microsoft.com/en-us/library/windows/desktop/ms680621.aspx
   ctypes.windll.kernel32.SetErrorMode(0x0001|0x0002|0x8000)
 
 
 class _streamingLinebuf(object):
   def __init__(self):
     self.buffedlines = []
-    self.extra = cStringIO.StringIO()
+    self.extra = StringIO.StringIO()
 
   def ingest(self, data):
     lines = data.splitlines()
     endedOnLinebreak = data.endswith("\n")
 
     if self.extra.tell():
       # we had leftovers from some previous ingest
       self.extra.write(lines[0])
       if len(lines) > 1 or endedOnLinebreak:
         lines[0] = self.extra.getvalue()
-        self.extra = cStringIO.StringIO()
+        self.extra = StringIO.StringIO()
       else:
         return
 
     if not endedOnLinebreak:
       self.extra.write(lines[-1])
       lines = lines[:-1]
 
     self.buffedlines += lines
 
   def get_buffered(self):
@@ skipping 342 matching lines @@
     # We modify step_dict.  In particular, we add ~followup_annotations during
     # finalize, and depend on that side-effect being carried into what we
     # added to self._step_history, earlier.  So copy it here so at least we
     # keep the modifications local.
     step_dict = dict(step_dict)
 
     test_data_fn = step_dict.pop('step_test_data', recipe_test_api.StepTestData)
     step_test = self._test_data.pop_step_test_data(
         step_dict['name'], test_data_fn)
     step_dict, placeholders = render_step(step_dict, step_test)
-    outstream = cStringIO.StringIO()
+    outstream = StringIO.StringIO()
 
     # Layer the simulation step on top of the given stream engine.
     step_stream = stream.ProductStreamEngine.StepStream(
         self._stream_engine.new_step_stream(step_dict['name']),
         stream.BareAnnotationStepStream(outstream))
 
     class ReturnOpenStep(OpenStep):
       def run(inner):
         timeout = step_dict.get('timeout')
         if (timeout and step_test.times_out_after and
@@ skipping 222 matching lines @@
   supplied command, and only uses the |env| kwarg for modifying the environment
   of the child process.
   """
   saved_path = os.environ['PATH']
   try:
     if path is not None:
       os.environ['PATH'] = path
     yield
   finally:
     os.environ['PATH'] = saved_path