#!/usr/bin/python3
# -*- coding: utf-8 -*-
########################################################################
#
# This file is part of python module <pySPC>.
# Copyright (C) 2013-2020 R. Marty
# (renaud.marty@developpement-durable.gouv.fr)
#
# 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 3 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 (see COPYING.txt).
# If not, see <http://www.gnu.org/licenses/>.
#
########################################################################
"""
Find and return the oldest file of input file names.
Only one wins tie. Values based on time distance from present.
Use of `_invert` inverts logic to make this a youngest routine,
to be used more clearly via `get_youngest_file`.
"""
import os
import time
import operator
[docs]
def get_oldest_file(files, _invert=False):
"""
Find and return the oldest file of input file names.
Only one wins tie. Values based on time distance from present.
Use of `_invert` inverts logic to make this a youngest routine,
to be used more clearly via `get_youngest_file`.
"""
gt = operator.lt if _invert else operator.gt
# Check for empty list.
if not files:
return None
# Raw epoch distance.
now = time.time()
# Select first as arbitrary sentinel file, storing name and age.
oldest = files[0], now - os.path.getctime(files[0])
# Iterate over all remaining files.
for f in files[1:]:
age = now - os.path.getctime(f)
if gt(age, oldest[1]):
# Set new oldest.
oldest = f, age
# Return just the name of oldest file.
return oldest[0]