mirror of https://github.com/morpheus65535/bazarr
91 lines
2.8 KiB
Python
91 lines
2.8 KiB
Python
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
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# Copyright (C) 2003-2017 Nominum, Inc.
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#
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# Permission to use, copy, modify, and distribute this software and its
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# documentation for any purpose with or without fee is hereby granted,
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# provided that the above copyright notice and this permission notice
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# appear in all copies.
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#
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# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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"""DNS TTL conversion."""
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import dns.exception
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# Technically TTLs are supposed to be between 0 and 2**31 - 1, with values
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# greater than that interpreted as 0, but we do not impose this policy here
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# as values > 2**31 - 1 occur in real world data.
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#
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# We leave it to applications to impose tighter bounds if desired.
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MAX_TTL = 2**32 - 1
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class BadTTL(dns.exception.SyntaxError):
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"""DNS TTL value is not well-formed."""
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def from_text(text):
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"""Convert the text form of a TTL to an integer.
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The BIND 8 units syntax for TTLs (e.g. '1w6d4h3m10s') is supported.
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*text*, a ``str``, the textual TTL.
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Raises ``dns.ttl.BadTTL`` if the TTL is not well-formed.
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Returns an ``int``.
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"""
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if text.isdigit():
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total = int(text)
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elif len(text) == 0:
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raise BadTTL
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else:
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total = 0
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current = 0
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need_digit = True
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for c in text:
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if c.isdigit():
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current *= 10
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current += int(c)
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need_digit = False
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else:
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if need_digit:
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raise BadTTL
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c = c.lower()
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if c == 'w':
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total += current * 604800
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elif c == 'd':
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total += current * 86400
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elif c == 'h':
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total += current * 3600
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elif c == 'm':
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total += current * 60
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elif c == 's':
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total += current
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else:
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raise BadTTL("unknown unit '%s'" % c)
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current = 0
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need_digit = True
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if not current == 0:
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raise BadTTL("trailing integer")
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if total < 0 or total > MAX_TTL:
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raise BadTTL("TTL should be between 0 and 2**32 - 1 (inclusive)")
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return total
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def make(value):
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if isinstance(value, int):
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return value
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elif isinstance(value, str):
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return dns.ttl.from_text(value)
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else:
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raise ValueError('cannot convert value to TTL')
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