[Findit] Add local git parsers.

appengine/findit/common/time_util.py

Index: appengine/findit/common/time_util.py
diff --git a/appengine/findit/common/time_util.py b/appengine/findit/common/time_util.py
index 4ef6e8b8a41a167b34bb2a3d5fb090fadf27bf2a..7aace1bc3eb81f41e134254f415f86af41c4fedb 100644
--- a/appengine/findit/common/time_util.py
+++ b/appengine/findit/common/time_util.py
@@ -66,3 +66,38 @@ def GetDatetimeInTimezone(timezone_name, date_time):
     A datetime.datetime of the given one in the specified timezone.
   """
   return date_time.astimezone(pytz.timezone(timezone_name))
+
+
+class TimeZoneInfo(object):

[stgao, 2016/11/02 02:04:20]

We already have the code to handle this in
https://chromium.googlesource.com/infra/infra/+/master/appengine/findit/lib/g...

Can we just refactor and reuse?

[Sharu Jiang, 2016/11/03 20:59:48]

Sure, I can refactor that code to use this TimeZoneInfo class.

+  """Gets time zone info from string like: +0800.
+
+  The string is HHMM offset relative to UTC timezone."""
+
+  def __init__(self, offset_str):
+    super(TimeZoneInfo, self).__init__()
+    self._utcoffset = self.GetOffsetFromStr(offset_str)
+
+  def GetOffsetFromStr(self, offset_str):
+    offset = int(offset_str[-4:-2]) * 60 + int(offset_str[-2:])
+    if offset_str[0] == '-':
+      offset = -offset
+    return timedelta(minutes=offset)
+
+  @property
+  def utcoffset(self):
+    return self._utcoffset
+
+  def LocalToUTC(self, naive_time):
+    """Localizes naive datetime and converts it to utc naive datetime.
+
+    Args:
+      naive_time(datetime): naive time in local time zone, for example '+0800'.
+
+    Return:
+      A naive datetime object in utc time zone.
+      For example:
+      For TimeZoneInfo('+0800'), and naive local time is
+      datetime(2016, 9, 1, 10, 0, 0), the returned result should be
+      datetime(2016, 9, 1, 18, 0, 0) in utc time.
+    """
+    return naive_time - self.utcoffset