~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005, 2006, 2007 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

import calendar

import time

from bzrlib import osutils

def format_highres_date(t, offset=0):

    """Format a date, such that it includes higher precision in the

    seconds field.

    :param t:   The local time in fractional seconds since the epoch

    :type t: float

    :param offset:  The timezone offset in integer seconds

    :type offset: int

    Example: format_highres_date(time.time(), -time.timezone)

    this will return a date stamp for right now,

    formatted for the local timezone.

    >>> from bzrlib.osutils import format_date

    >>> format_date(1120153132.350850105, 0)

    'Thu 2005-06-30 17:38:52 +0000'

    >>> format_highres_date(1120153132.350850105, 0)

    'Thu 2005-06-30 17:38:52.350850105 +0000'

    >>> format_date(1120153132.350850105, -5*3600)

    'Thu 2005-06-30 12:38:52 -0500'

    >>> format_highres_date(1120153132.350850105, -5*3600)

    'Thu 2005-06-30 12:38:52.350850105 -0500'

    >>> format_highres_date(1120153132.350850105, 7200)

    'Thu 2005-06-30 19:38:52.350850105 +0200'

    >>> format_highres_date(1152428738.867522, 19800)

    'Sun 2006-07-09 12:35:38.867522001 +0530'

    """

    assert isinstance(t, float)

    # This has to be formatted for "original" date, so that the

    # revision XML entry will be reproduced faithfully.

    if offset is None:

        offset = 0

    tt = time.gmtime(t + offset)

    return (time.strftime("%a %Y-%m-%d %H:%M:%S", tt)

            # Get the high-res seconds, but ignore the 0

            + ('%.9f' % (t - int(t)))[1:]

            + ' %+03d%02d' % (offset / 3600, (offset / 60) % 60))

def unpack_highres_date(date):

    """This takes the high-resolution date stamp, and

    converts it back into the tuple (timestamp, timezone)

    Where timestamp is in real UTC since epoch seconds, and timezone is an

    integer number of seconds offset.

    :param date: A date formated by format_highres_date

    :type date: string

    >>> import time, random

    >>> unpack_highres_date('Thu 2005-06-30 12:38:52.350850105 -0500')

    (1120153132.3508501, -18000)

    >>> unpack_highres_date('Thu 2005-06-30 17:38:52.350850105 +0000')

    (1120153132.3508501, 0)

    >>> unpack_highres_date('Thu 2005-06-30 19:38:52.350850105 +0200')

    (1120153132.3508501, 7200)

    >>> unpack_highres_date('Sun 2006-07-09 12:35:38.867522001 +0530')

    (1152428738.867522, 19800)

    >>> from bzrlib.osutils import local_time_offset

    >>> t = time.time()

    >>> o = local_time_offset()

    >>> t2, o2 = unpack_highres_date(format_highres_date(t, o))

    >>> t == t2

    True

    >>> o == o2

    True

    >>> t -= 24*3600*365*2 # Start 2 years ago

    >>> o = -12*3600

    >>> for count in xrange(500):

    ...   t += random.random()*24*3600*30

    ...   o = ((o/3600 + 13) % 25 - 12)*3600 # Add 1 wrap around from [-12, 12]

    ...   date = format_highres_date(t, o)

    ...   t2, o2 = unpack_highres_date(date)

    ...   if t != t2 or o != o2:

    ...      print 'Failed on date %r, %s,%s diff:%s' % (date, t, o, t2-t)

    ...      break

    """

    # Up until the first period is a datestamp that is generated

    # as normal from time.strftime, so use time.strptime to

    # parse it

    dot_loc = date.find('.')

    if dot_loc == -1:

        raise ValueError(

            'Date string does not contain high-precision seconds: %r' % date)

    base_time = time.strptime(date[:dot_loc], "%a %Y-%m-%d %H:%M:%S")

    fract_seconds, offset = date[dot_loc:].split()

    fract_seconds = float(fract_seconds)

    offset = int(offset)

    hours = int(offset / 100)

    minutes = (offset % 100)

    seconds_offset = (hours * 3600) + (minutes * 60)

    # time.mktime returns localtime, but calendar.timegm returns UTC time

    timestamp = calendar.timegm(base_time)

    timestamp -= seconds_offset

    # Add back in the fractional seconds

    timestamp += fract_seconds

    return (timestamp, seconds_offset)

def format_patch_date(secs, offset=0):

    """Format a POSIX timestamp and optional offset as a patch-style date.

    Inverse of parse_patch_date.

    """

    assert offset % 60 == 0, \

        "can't represent timezone %s offset by fractional minutes" % offset

    # so that we don't need to do calculations on pre-epoch times, 

    # which doesn't work with win32 python gmtime, we always

    # give the epoch in utc

    if secs == 0:

        offset = 0

    if secs + offset < 0:

        from warnings import warn

        warn("gmtime of negative time (%s, %s) may not work on Windows" %

                (secs, offset))

    return osutils.format_date(secs, offset=offset,

            date_fmt='%Y-%m-%d %H:%M:%S')

def parse_patch_date(date_str):

    """Parse a patch-style date into a POSIX timestamp and offset.

    Inverse of format_patch_date.

    """

    secs_str = date_str[:-6]

    offset_str = date_str[-5:]

    assert len(offset_str) == 5, \

            "invalid timezone %r" % offset_str

    offset_hours, offset_mins = offset_str[:3], offset_str[3:]

    offset = int(offset_hours) * 3600 + int(offset_mins) * 60

    tm_time = time.strptime(secs_str, '%Y-%m-%d %H:%M:%S')

    # adjust seconds according to offset before converting to POSIX

    # timestamp, to avoid edge problems

    tm_time = tm_time[:5] + (tm_time[5] - offset,) + tm_time[6:]

    secs = calendar.timegm(tm_time)

    return secs, offset