# Copyright (C) 2003-2007, 2009-2011 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""DNS name dictionary"""
import dns.name
class NameDict(dict):
"""A dictionary whose keys are dns.name.Name objects.
@ivar max_depth: the maximum depth of the keys that have ever been
added to the dictionary.
@type max_depth: int
"""
def __init__(self, *args, **kwargs):
super(NameDict, self).__init__(*args, **kwargs)
self.max_depth = 0
def __setitem__(self, key, value):
if not isinstance(key, dns.name.Name):
raise ValueError('NameDict key must be a name')
depth = len(key)
if depth > self.max_depth:
self.max_depth = depth
super(NameDict, self).__setitem__(key, value)
def get_deepest_match(self, name):
"""Find the deepest match to I{name} in the dictionary.
The deepest match is the longest name in the dictionary which is
a superdomain of I{name}.
@param name: the name
@type name: dns.name.Name object
@rtype: (key, value) tuple
"""
depth = len(name)
if depth > self.max_depth:
depth = self.max_depth
for i in xrange(-depth, 0):
n = dns.name.Name(name[i:])
if self.has_key(n):
return (n, self[n])
v = self[dns.name.empty]
return (dns.name.empty, v)