lib/dnspython/dns/namedict.py

   1 # Copyright (C) 2003-2007, 2009-2011 Nominum, Inc.
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  15
  16 """DNS name dictionary"""
  17
  18 import dns.name
  19
  20 class NameDict(dict):
  21
  22     """A dictionary whose keys are dns.name.Name objects.
  23     @ivar max_depth: the maximum depth of the keys that have ever been
  24     added to the dictionary.
  25     @type max_depth: int
  26     """
  27
  28     def __init__(self, *args, **kwargs):
  29         super(NameDict, self).__init__(*args, **kwargs)
  30         self.max_depth = 0
  31
  32     def __setitem__(self, key, value):
  33         if not isinstance(key, dns.name.Name):
  34             raise ValueError('NameDict key must be a name')
  35         depth = len(key)
  36         if depth > self.max_depth:
  37             self.max_depth = depth
  38         super(NameDict, self).__setitem__(key, value)
  39
  40     def get_deepest_match(self, name):
  41         """Find the deepest match to I{name} in the dictionary.
  42
  43         The deepest match is the longest name in the dictionary which is
  44         a superdomain of I{name}.
  45
  46         @param name: the name
  47         @type name: dns.name.Name object
  48         @rtype: (key, value) tuple
  49         """
  50
  51         depth = len(name)
  52         if depth > self.max_depth:
  53             depth = self.max_depth
  54         for i in xrange(-depth, 0):
  55             n = dns.name.Name(name[i:])
  56             if self.has_key(n):
  57                 return (n, self[n])
  58         v = self[dns.name.empty]
  59         return (dns.name.empty, v)