mapnik/scons/scons-local-0.96.1/SCons/Sig/TimeStamp.py

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2006-01-31 23:09:52 +00:00
"""SCons.Sig.TimeStamp
The TimeStamp signature package for the SCons software construction
utility.
"""
#
# Copyright (c) 2001, 2002, 2003, 2004 The SCons Foundation
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
__revision__ = "/home/scons/scons/branch.0/baseline/src/engine/SCons/Sig/TimeStamp.py 0.96.1.D001 2004/08/23 09:55:29 knight"
def current(new, old):
"""Return whether a new timestamp is up-to-date with
respect to an old timestamp.
"""
return not old is None and new <= old
def collect(signatures):
"""
Collect a list of timestamps, returning
the most-recent timestamp from the list
signatures - a list of timestamps
returns - the most recent timestamp
"""
if len(signatures) == 0:
return 0
elif len(signatures) == 1:
return signatures[0]
else:
return max(signatures)
def signature(obj):
"""Generate a timestamp.
"""
return obj.get_timestamp()
def to_string(signature):
"""Convert a timestamp to a string"""
return str(signature)
def from_string(string):
"""Convert a string to a timestamp"""
try:
return int(string)
except ValueError:
# if the signature isn't an int, then
# the user probably just switched from
# MD5 signatures to timestamp signatures,
# so ignore the error:
return None