| 1 | # Copyright (C) 2003-2007, 2009, 2010 Nominum, Inc.
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| 2 | #
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| 3 | # Permission to use, copy, modify, and distribute this software and its
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| 4 | # documentation for any purpose with or without fee is hereby granted,
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| 5 | # provided that the above copyright notice and this permission notice
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| 6 | # appear in all copies.
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| 7 | #
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| 8 | # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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| 9 | # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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| 10 | # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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| 11 | # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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| 12 | # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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| 13 | # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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| 14 | # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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| 15 |
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| 16 | """DNS name dictionary"""
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| 17 |
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| 18 | import dns.name
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| 19 |
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| 20 | class NameDict(dict):
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| 21 |
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| 22 | """A dictionary whose keys are dns.name.Name objects.
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| 23 | @ivar max_depth: the maximum depth of the keys that have ever been
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| 24 | added to the dictionary.
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| 25 | @type max_depth: int
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| 26 | """
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| 27 |
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| 28 | def __init__(self, *args, **kwargs):
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| 29 | super(NameDict, self).__init__(*args, **kwargs)
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| 30 | self.max_depth = 0
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| 31 |
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| 32 | def __setitem__(self, key, value):
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| 33 | if not isinstance(key, dns.name.Name):
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| 34 | raise ValueError('NameDict key must be a name')
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| 35 | depth = len(key)
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| 36 | if depth > self.max_depth:
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| 37 | self.max_depth = depth
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| 38 | super(NameDict, self).__setitem__(key, value)
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| 39 |
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| 40 | def get_deepest_match(self, name):
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| 41 | """Find the deepest match to I{name} in the dictionary.
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| 42 |
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| 43 | The deepest match is the longest name in the dictionary which is
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| 44 | a superdomain of I{name}.
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| 45 |
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| 46 | @param name: the name
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| 47 | @type name: dns.name.Name object
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| 48 | @rtype: (key, value) tuple
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| 49 | """
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| 50 |
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| 51 | depth = len(name)
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| 52 | if depth > self.max_depth:
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| 53 | depth = self.max_depth
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| 54 | for i in xrange(-depth, 0):
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| 55 | n = dns.name.Name(name[i:])
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| 56 | if self.has_key(n):
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| 57 | return (n, self[n])
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| 58 | v = self[dns.name.empty]
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| 59 | return (dns.name.empty, v)
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