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15
16"""DNS RRsets (an RRset is a named rdataset)"""
17
18import dns.name
19import dns.rdataset
20import dns.rdataclass
21import dns.renderer
22
23class RRset(dns.rdataset.Rdataset):
24    """A DNS RRset (named rdataset).
25
26    RRset inherits from Rdataset, and RRsets can be treated as
27    Rdatasets in most cases.  There are, however, a few notable
28    exceptions.  RRsets have different to_wire() and to_text() method
29    arguments, reflecting the fact that RRsets always have an owner
30    name.
31    """
32
33    __slots__ = ['name', 'deleting']
34
35    def __init__(self, name, rdclass, rdtype, covers=dns.rdatatype.NONE,
36                 deleting=None):
37        """Create a new RRset."""
38
39        super(RRset, self).__init__(rdclass, rdtype)
40        self.name = name
41        self.deleting = deleting
42
43    def _clone(self):
44        obj = super(RRset, self)._clone()
45        obj.name = self.name
46        obj.deleting = self.deleting
47        return obj
48
49    def __repr__(self):
50        if self.covers == 0:
51            ctext = ''
52        else:
53            ctext = '(' + dns.rdatatype.to_text(self.covers) + ')'
54        if not self.deleting is None:
55            dtext = ' delete=' + dns.rdataclass.to_text(self.deleting)
56        else:
57            dtext = ''
58        return '<DNS ' + str(self.name) + ' ' + \
59               dns.rdataclass.to_text(self.rdclass) + ' ' + \
60               dns.rdatatype.to_text(self.rdtype) + ctext + dtext + ' RRset>'
61
62    def __str__(self):
63        return self.to_text()
64
65    def __eq__(self, other):
66        """Two RRsets are equal if they have the same name and the same
67        rdataset
68
69        @rtype: bool"""
70        if not isinstance(other, RRset):
71            return False
72        if self.name != other.name:
73            return False
74        return super(RRset, self).__eq__(other)
75
76    def match(self, name, rdclass, rdtype, covers, deleting=None):
77        """Returns True if this rrset matches the specified class, type,
78        covers, and deletion state."""
79
80        if not super(RRset, self).match(rdclass, rdtype, covers):
81            return False
82        if self.name != name or self.deleting != deleting:
83            return False
84        return True
85
86    def to_text(self, origin=None, relativize=True, **kw):
87        """Convert the RRset into DNS master file format.
88
89        @see: L{dns.name.Name.choose_relativity} for more information
90        on how I{origin} and I{relativize} determine the way names
91        are emitted.
92
93        Any additional keyword arguments are passed on to the rdata
94        to_text() method.
95
96        @param origin: The origin for relative names, or None.
97        @type origin: dns.name.Name object
98        @param relativize: True if names should names be relativized
99        @type relativize: bool"""
100
101        return super(RRset, self).to_text(self.name, origin, relativize,
102                                          self.deleting, **kw)
103
104    def to_wire(self, file, compress=None, origin=None, **kw):
105        """Convert the RRset to wire format."""
106
107        return super(RRset, self).to_wire(self.name, file, compress, origin,
108                                          self.deleting, **kw)
109
110    def to_rdataset(self):
111        """Convert an RRset into an Rdataset.
112
113        @rtype: dns.rdataset.Rdataset object
114        """
115        return dns.rdataset.from_rdata_list(self.ttl, list(self))
116
117
118def from_text_list(name, ttl, rdclass, rdtype, text_rdatas):
119    """Create an RRset with the specified name, TTL, class, and type, and with
120    the specified list of rdatas in text format.
121
122    @rtype: dns.rrset.RRset object
123    """
124
125    if isinstance(name, (str, unicode)):
126        name = dns.name.from_text(name, None)
127    if isinstance(rdclass, str):
128        rdclass = dns.rdataclass.from_text(rdclass)
129    if isinstance(rdtype, str):
130        rdtype = dns.rdatatype.from_text(rdtype)
131    r = RRset(name, rdclass, rdtype)
132    r.update_ttl(ttl)
133    for t in text_rdatas:
134        rd = dns.rdata.from_text(r.rdclass, r.rdtype, t)
135        r.add(rd)
136    return r
137
138def from_text(name, ttl, rdclass, rdtype, *text_rdatas):
139    """Create an RRset with the specified name, TTL, class, and type and with
140    the specified rdatas in text format.
141
142    @rtype: dns.rrset.RRset object
143    """
144
145    return from_text_list(name, ttl, rdclass, rdtype, text_rdatas)
146
147def from_rdata_list(name, ttl, rdatas):
148    """Create an RRset with the specified name and TTL, and with
149    the specified list of rdata objects.
150
151    @rtype: dns.rrset.RRset object
152    """
153
154    if isinstance(name, (str, unicode)):
155        name = dns.name.from_text(name, None)
156
157    if len(rdatas) == 0:
158        raise ValueError("rdata list must not be empty")
159    r = None
160    for rd in rdatas:
161        if r is None:
162            r = RRset(name, rd.rdclass, rd.rdtype)
163            r.update_ttl(ttl)
164            first_time = False
165        r.add(rd)
166    return r
167
168def from_rdata(name, ttl, *rdatas):
169    """Create an RRset with the specified name and TTL, and with
170    the specified rdata objects.
171
172    @rtype: dns.rrset.RRset object
173    """
174
175    return from_rdata_list(name, ttl, rdatas)
176