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Diffstat (limited to 'lib/dnspython/dns/node.py')
| -rw-r--r-- | lib/dnspython/dns/node.py | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/lib/dnspython/dns/node.py b/lib/dnspython/dns/node.py new file mode 100644 index 0000000000..785a245464 --- /dev/null +++ b/lib/dnspython/dns/node.py @@ -0,0 +1,172 @@ +# Copyright (C) 2001-2007, 2009, 2010 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 nodes. A node is a set of rdatasets.""" + +import StringIO + +import dns.rdataset +import dns.rdatatype +import dns.renderer + +class Node(object): + """A DNS node. + + A node is a set of rdatasets + + @ivar rdatasets: the node's rdatasets + @type rdatasets: list of dns.rdataset.Rdataset objects""" + + __slots__ = ['rdatasets'] + + def __init__(self): + """Initialize a DNS node. + """ + + self.rdatasets = []; + + def to_text(self, name, **kw): + """Convert a node to text format. + + Each rdataset at the node is printed. Any keyword arguments + to this method are passed on to the rdataset's to_text() method. + @param name: the owner name of the rdatasets + @type name: dns.name.Name object + @rtype: string + """ + + s = StringIO.StringIO() + for rds in self.rdatasets: + print >> s, rds.to_text(name, **kw) + return s.getvalue()[:-1] + + def __repr__(self): + return '<DNS node ' + str(id(self)) + '>' + + def __eq__(self, other): + """Two nodes are equal if they have the same rdatasets. + + @rtype: bool + """ + # + # This is inefficient. Good thing we don't need to do it much. + # + for rd in self.rdatasets: + if rd not in other.rdatasets: + return False + for rd in other.rdatasets: + if rd not in self.rdatasets: + return False + return True + + def __ne__(self, other): + return not self.__eq__(other) + + def __len__(self): + return len(self.rdatasets) + + def __iter__(self): + return iter(self.rdatasets) + + def find_rdataset(self, rdclass, rdtype, covers=dns.rdatatype.NONE, + create=False): + """Find an rdataset matching the specified properties in the + current node. + + @param rdclass: The class of the rdataset + @type rdclass: int + @param rdtype: The type of the rdataset + @type rdtype: int + @param covers: The covered type. Usually this value is + dns.rdatatype.NONE, but if the rdtype is dns.rdatatype.SIG or + dns.rdatatype.RRSIG, then the covers value will be the rdata + type the SIG/RRSIG covers. The library treats the SIG and RRSIG + types as if they were a family of + types, e.g. RRSIG(A), RRSIG(NS), RRSIG(SOA). This makes RRSIGs much + easier to work with than if RRSIGs covering different rdata + types were aggregated into a single RRSIG rdataset. + @type covers: int + @param create: If True, create the rdataset if it is not found. + @type create: bool + @raises KeyError: An rdataset of the desired type and class does + not exist and I{create} is not True. + @rtype: dns.rdataset.Rdataset object + """ + + for rds in self.rdatasets: + if rds.match(rdclass, rdtype, covers): + return rds + if not create: + raise KeyError + rds = dns.rdataset.Rdataset(rdclass, rdtype) + self.rdatasets.append(rds) + return rds + + def get_rdataset(self, rdclass, rdtype, covers=dns.rdatatype.NONE, + create=False): + """Get an rdataset matching the specified properties in the + current node. + + None is returned if an rdataset of the specified type and + class does not exist and I{create} is not True. + + @param rdclass: The class of the rdataset + @type rdclass: int + @param rdtype: The type of the rdataset + @type rdtype: int + @param covers: The covered type. + @type covers: int + @param create: If True, create the rdataset if it is not found. + @type create: bool + @rtype: dns.rdataset.Rdataset object or None + """ + + try: + rds = self.find_rdataset(rdclass, rdtype, covers, create) + except KeyError: + rds = None + return rds + + def delete_rdataset(self, rdclass, rdtype, covers=dns.rdatatype.NONE): + """Delete the rdataset matching the specified properties in the + current node. + + If a matching rdataset does not exist, it is not an error. + + @param rdclass: The class of the rdataset + @type rdclass: int + @param rdtype: The type of the rdataset + @type rdtype: int + @param covers: The covered type. + @type covers: int + """ + + rds = self.get_rdataset(rdclass, rdtype, covers) + if not rds is None: + self.rdatasets.remove(rds) + + def replace_rdataset(self, replacement): + """Replace an rdataset. + + It is not an error if there is no rdataset matching I{replacement}. + + Ownership of the I{replacement} object is transferred to the node; + in other words, this method does not store a copy of I{replacement} + at the node, it stores I{replacement} itself. + """ + + self.delete_rdataset(replacement.rdclass, replacement.rdtype, + replacement.covers) + self.rdatasets.append(replacement) |