[GitHub] incubator-ariatosca pull request #100: ARIA-140 Version utils

[AviaE <gi...@git.apache.org>]

Github user AviaE commented on a diff in the pull request:

    https://github.com/apache/incubator-ariatosca/pull/100#discussion_r115142886
  
    --- Diff: aria/utils/versions.py ---
    @@ -0,0 +1,162 @@
    +# Licensed to the Apache Software Foundation (ASF) under one or more
    +# contributor license agreements.  See the NOTICE file distributed with
    +# this work for additional information regarding copyright ownership.
    +# The ASF licenses this file to You under the Apache License, Version 2.0
    +# (the "License"); you may not use this file except in compliance with
    +# the License.  You may obtain a copy of the License at
    +#
    +#     http://www.apache.org/licenses/LICENSE-2.0
    +#
    +# Unless required by applicable law or agreed to in writing, software
    +# distributed under the License is distributed on an "AS IS" BASIS,
    +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    +# See the License for the specific language governing permissions and
    +# limitations under the License.
    +
    +"""
    +General-purpose version string handling
    +"""
    +
    +import re
    +
    +
    +_INF = float('inf')
    +
    +_NULL = (), _INF
    +
    +_DIGITS_RE = re.compile(r'^\d+$')
    +
    +_PREFIXES = {
    +    'dev':   0.0001,
    +    'alpha': 0.001,
    +    'beta':  0.01,
    +    'rc':    0.1
    +}
    +
    +
    +class VersionString(unicode):
    +    """
    +    Version string that can be compared, sorted, made unique in a set, and used as a unique dict
    +    key.
    +
    +    The primary part of the string is one or more dot-separated natural numbers. Trailing zeroes
    +    are treated as redundant, e.g. "1.0.0" == "1.0" == "1".
    +
    +    An optional qualifier can be added after a "-". The qualifier can be a natural number or a
    +    specially treated prefixed natural number, e.g. "1.1-beta1" > "1.1-alpha2". The case of the
    +    prefix is ignored.
    +
    +    Numeric qualifiers will always be greater than prefixed integer qualifiers, e.g. "1.1-1" >
    +    "1.1-beta1".
    +
    +    Versions without a qualifier will always be greater than their equivalents with a qualifier,
    +    e.g. e.g. "1.1" > "1.1-1".
    +
    +    Any value that does not conform to this format will be treated as a zero version, which would
    +    be lesser than any non-zero version.
    +
    +    For efficient list sorts use the ``key`` property, e.g.:
    +    ``sorted(versions, key=lambda x: x.key)``
    +    """
    +
    +    NULL = None # initialized below
    +
    +    def __init__(self, value=None):
    +        if value is not None:
    +            super(VersionString, self).__init__(value)
    +        self.key = parse_version_string(self)
    +
    +    def __eq__(self, version):
    +        if not isinstance(version, VersionString):
    +            version = VersionString(version)
    +        return self.key == version.key
    +
    +    def __lt__(self, version):
    +        if not isinstance(version, VersionString):
    +            version = VersionString(version)
    +        return self.key < version.key
    +
    +    def __hash__(self):
    +        return self.key.__hash__()
    +
    +
    +def parse_version_string(version): # pylint: disable=too-many-branches
    +    """
    +    Parses a version string.
    +
    +    :param version: The version string
    +    :returns: The primary tuple and qualifier float
    +    :rtype: ((int), float)
    +    """
    +
    +    if version is None:
    +        return _NULL
    +    version = unicode(version)
    +
    +    # Split to primary and qualifier on '-'
    +    split = version.split('-', 2)
    +    if len(split) == 2:
    +        primary, qualifier = split
    +    else:
    --- End diff --
    
    The `2` in `split` means you include the part to the right of the second separator as the third element in the result.
    Which means that if you get passed `1.2-3-beta4`, you will treat it as a valid version string with the value `1.2`.


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