# This file is part of Pimlico
# Copyright (C) 2020 Mark Granroth-Wilding
# Licensed under the GNU LGPL v3.0 - https://www.gnu.org/licenses/lgpl-3.0.en.html
from past.builtins import cmp
from builtins import object
[docs]class SoftwareVersion(object):
"""
Base class for representing version numbers / IDs of software. Different software may use different conventions
to represent its versions, so it may be necessary to subclass this class to provide the appropriate parsing
and comparison of versions.
"""
def __init__(self, string_id):
self.string_id = string_id
def __str__(self):
return self.string_id
def __eq__(self, other):
if self.string_id == "unknown" and other.string_id == "unknown":
return True
else:
return compare_dotted_versions(self.string_id, other.string_id) == 0
def __lt__(self, other):
if self.string_id == "unknown":
# Any known version is considered later than an unknown version
return False
elif other.string_id == "unknown":
# Any known version is considered later than an unknown version
return True
else:
# Compare the string IDs on the assumption that they're dotted version numbers
return compare_dotted_versions(self.string_id, other.string_id) < 0
# Define here, so that it can easily be used symbolically
unknown_software_version = SoftwareVersion("unknown")
[docs]def compare_dotted_versions(version0, version1):
"""
Comparison function for reasonably standard version numbers, with subversions to any level of nesting specified
by dots.
"""
remaining0 = version0
remaining1 = version1
while len(remaining0):
if len(remaining1) == 0:
# Version 0 has the same prefix, but specifies more subversions, so is a later release
return 1
version0_part, __, remaining0 = remaining0.partition(".")
version1_part, __, remaining1 = remaining1.partition(".")
# Don't distinguish letters by case
version0_part, version1_part = version0_part.lower(), version1_part.lower()
# Try converting both segments to ints
try:
version0_part_int = int(version0_part)
except ValueError:
# Version 0 isn't an int: see whether version 1 is
try:
int(version1_part)
except ValueError:
# Neither is an int: first check whether they're identical
if version0_part == version1_part:
# Continue to next part
continue
# Otherwise, compare string lexicographically and return result without looking at deeper parts
return -1 if version0_part < version1_part else 1
else:
# V1 is an int, V0 isn't: int wins
return -1
try:
version1_part_int = int(version1_part)
except ValueError:
# V1 isn't an int, but V0 is: int wins
return 1
# Both parts are ints
if version0_part_int == version1_part_int:
# Equal: continue to next level
continue
else:
# Not the same: the one that wins at this level wins the whole thing
return -1 if version0_part_int < version1_part_int else 1
if len(remaining1) > 0:
# Version 1 has same prefix, but more subversions, so is later
return -1
else:
# Got to the end of both versions without reaching a conclusion: they must be equal
return 0