61 lines
2.7 KiB
Python
61 lines
2.7 KiB
Python
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import re
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# Stolen from pkg_resources, but importing it is not a good idea
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component_re = re.compile(r'(\d+ | [a-z]+ | \.| -)', re.VERBOSE)
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replace = {'pre':'c', 'preview':'c','-':'final-','rc':'c','dev':'@'}.get
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def _parse_version_parts(s):
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for part in component_re.split(s):
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part = replace(part,part)
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if not part or part=='.':
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continue
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if part[:1] in '0123456789':
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yield part.zfill(8) # pad for numeric comparison
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else:
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yield '*'+part
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yield '*final' # ensure that alpha/beta/candidate are before final
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def parse_version(s):
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"""Convert a version string to a chronologically-sortable key
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This is a rough cross between distutils' StrictVersion and LooseVersion;
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if you give it versions that would work with StrictVersion, then it behaves
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the same; otherwise it acts like a slightly-smarter LooseVersion. It is
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*possible* to create pathological version coding schemes that will fool
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this parser, but they should be very rare in practice.
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The returned value will be a tuple of strings. Numeric portions of the
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version are padded to 8 digits so they will compare numerically, but
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without relying on how numbers compare relative to strings. Dots are
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dropped, but dashes are retained. Trailing zeros between alpha segments
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or dashes are suppressed, so that e.g. "2.4.0" is considered the same as
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"2.4". Alphanumeric parts are lower-cased.
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The algorithm assumes that strings like "-" and any alpha string that
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alphabetically follows "final" represents a "patch level". So, "2.4-1"
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is assumed to be a branch or patch of "2.4", and therefore "2.4.1" is
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considered newer than "2.4-1", which in turn is newer than "2.4".
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Strings like "a", "b", "c", "alpha", "beta", "candidate" and so on (that
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come before "final" alphabetically) are assumed to be pre-release versions,
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so that the version "2.4" is considered newer than "2.4a1".
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Finally, to handle miscellaneous cases, the strings "pre", "preview", and
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"rc" are treated as if they were "c", i.e. as though they were release
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candidates, and therefore are not as new as a version string that does not
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contain them, and "dev" is replaced with an '@' so that it sorts lower than
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than any other pre-release tag.
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"""
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parts = []
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for part in _parse_version_parts(s.lower()):
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if part.startswith('*'):
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if part<'*final': # remove '-' before a prerelease tag
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while parts and parts[-1]=='*final-': parts.pop()
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# remove trailing zeros from each series of numeric parts
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while parts and parts[-1]=='00000000':
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parts.pop()
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parts.append(part)
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return tuple(parts)
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