Source Code for Module psycopg2.tz

  1  """tzinfo implementations for psycopg2 
  2   
  3  This module holds two different tzinfo implementations that can be used as 
  4  the 'tzinfo' argument to datetime constructors, directly passed to psycopg 
  5  functions or used to set the .tzinfo_factory attribute in cursors.  
  6  """ 
  7  # psycopg/tz.py - tzinfo implementation 
  8  # 
  9  # Copyright (C) 2003-2004 Federico Di Gregorio  <fog@debian.org> 
 10  # 
 11  # This program is free software; you can redistribute it and/or modify 
 12  # it under the terms of the GNU General Public License as published by the 
 13  # Free Software Foundation; either version 2, or (at your option) any later 
 14  # version. 
 15  # 
 16  # This program is distributed in the hope that it will be useful, but 
 17  # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY 
 18  # or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License 
 19  # for more details. 
 20   
 21  import datetime 
 22  import time 
 23   
 24   
 25  ZERO = datetime.timedelta(0) 
 26   
 27 -class FixedOffsetTimezone(datetime.tzinfo): 
 28      """Fixed offset in minutes east from UTC. 
 29   
 30      This is exactly the implementation found in Python 2.3.x documentation, 
 31      with a small change to the __init__ method to allow for pickling and a 
 32      default name in the form 'sHH:MM' ('s' is the sign.) 
 33      """ 
 34      _name = None 
 35      _offset = ZERO 
 36       
 37 -    def __init__(self, offset=None, name=None): 
 38          if offset is not None: 
 39              self._offset = datetime.timedelta(minutes = offset) 
 40          if name is not None: 
 41              self._name = name 
 42   
 43 -    def utcoffset(self, dt): 
 44          return self._offset 
 45   
 46 -    def tzname(self, dt): 
 47          if self._name is not None: 
 48              return self._name 
 49          else: 
 50              seconds = self._offset.seconds + self._offset.days * 86400 
 51              hours, seconds = divmod(seconds, 3600) 
 52              minutes = seconds/60 
 53              if minutes: 
 54                  return "%+03d:%d" % (hours, minutes) 
 55              else: 
 56                  return "%+03d" % hours 
 57               
 58 -    def dst(self, dt): 
 59          return ZERO 
 60   
 61   
 62  STDOFFSET = datetime.timedelta(seconds = -time.timezone) 
 63  if time.daylight: 
 64      DSTOFFSET = datetime.timedelta(seconds = -time.altzone) 
 65  else: 
 66      DSTOFFSET = STDOFFSET 
 67  DSTDIFF = DSTOFFSET - STDOFFSET 
 68   
 69 -class LocalTimezone(datetime.tzinfo): 
 70      """Platform idea of local timezone. 
 71   
 72      This is the exact implementation from the Pyhton 2.3 documentation. 
 73      """ 
 74       
 75 -    def utcoffset(self, dt): 
 76          if self._isdst(dt): 
 77              return DSTOFFSET 
 78          else: 
 79              return STDOFFSET 
 80   
 81 -    def dst(self, dt): 
 82          if self._isdst(dt): 
 83              return DSTDIFF 
 84          else: 
 85              return ZERO 
 86   
 87 -    def tzname(self, dt): 
 88          return time.tzname[self._isdst(dt)] 
 89   
 90 -    def _isdst(self, dt): 
 91          tt = (dt.year, dt.month, dt.day, 
 92                dt.hour, dt.minute, dt.second, 
 93                dt.weekday(), 0, -1) 
 94          stamp = time.mktime(tt) 
 95          tt = time.localtime(stamp) 
 96          return tt.tm_isdst > 0 
 97   
 98  LOCAL = LocalTimezone() 
 99   
100  # TODO: pre-generate some interesting time zones? 
101