Mini Shell

# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license

# Copyright (C) 2003-2017 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 RRsets (an RRset is a named rdataset)"""


import dns.name
import dns.rdataset
import dns.rdataclass
import dns.renderer


class RRset(dns.rdataset.Rdataset):

    """A DNS RRset (named rdataset).

    RRset inherits from Rdataset, and RRsets can be treated as
    Rdatasets in most cases.  There are, however, a few notable
    exceptions.  RRsets have different to_wire() and to_text() method
    arguments, reflecting the fact that RRsets always have an owner
    name.
    """

    __slots__ = ['name', 'deleting']

    def __init__(self, name, rdclass, rdtype, covers=dns.rdatatype.NONE,
                 deleting=None):
        """Create a new RRset."""

        super().__init__(rdclass, rdtype, covers)
        self.name = name
        self.deleting = deleting

    def _clone(self):
        obj = super()._clone()
        obj.name = self.name
        obj.deleting = self.deleting
        return obj

    def __repr__(self):
        if self.covers == 0:
            ctext = ''
        else:
            ctext = '(' + dns.rdatatype.to_text(self.covers) + ')'
        if self.deleting is not None:
            dtext = ' delete=' + dns.rdataclass.to_text(self.deleting)
        else:
            dtext = ''
        return '<DNS ' + str(self.name) + ' ' + \
               dns.rdataclass.to_text(self.rdclass) + ' ' + \
               dns.rdatatype.to_text(self.rdtype) + ctext + dtext + \
               ' RRset: ' + self._rdata_repr() + '>'

    def __str__(self):
        return self.to_text()

    def __eq__(self, other):
        if not isinstance(other, RRset):
            return False
        if self.name != other.name:
            return False
        return super().__eq__(other)

    def match(self, name, rdclass, rdtype, covers, deleting=None):
        """Returns ``True`` if this rrset matches the specified class, type,
        covers, and deletion state.
        """

        if not super().match(rdclass, rdtype, covers):
            return False
        if self.name != name or self.deleting != deleting:
            return False
        return True

    def to_text(self, origin=None, relativize=True, **kw):
        """Convert the RRset into DNS master file format.

        See ``dns.name.Name.choose_relativity`` for more information
        on how *origin* and *relativize* determine the way names
        are emitted.

        Any additional keyword arguments are passed on to the rdata
        ``to_text()`` method.

        *origin*, a ``dns.name.Name`` or ``None``, the origin for relative
        names.

        *relativize*, a ``bool``.  If ``True``, names will be relativized
        to *origin*.
        """

        return super().to_text(self.name, origin, relativize,
                               self.deleting, **kw)

    def to_wire(self, file, compress=None, origin=None, **kw):
        """Convert the RRset to wire format.

        All keyword arguments are passed to ``dns.rdataset.to_wire()``; see
        that function for details.

        Returns an ``int``, the number of records emitted.
        """

        return super().to_wire(self.name, file, compress, origin,
                               self.deleting, **kw)

    def to_rdataset(self):
        """Convert an RRset into an Rdataset.

        Returns a ``dns.rdataset.Rdataset``.
        """
        return dns.rdataset.from_rdata_list(self.ttl, list(self))


def from_text_list(name, ttl, rdclass, rdtype, text_rdatas,
                   idna_codec=None):
    """Create an RRset with the specified name, TTL, class, and type, and with
    the specified list of rdatas in text format.

    *idna_codec*, a ``dns.name.IDNACodec``, specifies the IDNA
    encoder/decoder to use; if ``None``, the default IDNA 2003
    encoder/decoder is used.

    Returns a ``dns.rrset.RRset`` object.
    """

    if isinstance(name, str):
        name = dns.name.from_text(name, None, idna_codec=idna_codec)
    rdclass = dns.rdataclass.RdataClass.make(rdclass)
    rdtype = dns.rdatatype.RdataType.make(rdtype)
    r = RRset(name, rdclass, rdtype)
    r.update_ttl(ttl)
    for t in text_rdatas:
        rd = dns.rdata.from_text(r.rdclass, r.rdtype, t, idna_codec=idna_codec)
        r.add(rd)
    return r


def from_text(name, ttl, rdclass, rdtype, *text_rdatas):
    """Create an RRset with the specified name, TTL, class, and type and with
    the specified rdatas in text format.

    Returns a ``dns.rrset.RRset`` object.
    """

    return from_text_list(name, ttl, rdclass, rdtype, text_rdatas)


def from_rdata_list(name, ttl, rdatas, idna_codec=None):
    """Create an RRset with the specified name and TTL, and with
    the specified list of rdata objects.

    *idna_codec*, a ``dns.name.IDNACodec``, specifies the IDNA
    encoder/decoder to use; if ``None``, the default IDNA 2003
    encoder/decoder is used.

    Returns a ``dns.rrset.RRset`` object.

    """

    if isinstance(name, str):
        name = dns.name.from_text(name, None, idna_codec=idna_codec)

    if len(rdatas) == 0:
        raise ValueError("rdata list must not be empty")
    r = None
    for rd in rdatas:
        if r is None:
            r = RRset(name, rd.rdclass, rd.rdtype)
            r.update_ttl(ttl)
        r.add(rd)
    return r


def from_rdata(name, ttl, *rdatas):
    """Create an RRset with the specified name and TTL, and with
    the specified rdata objects.

    Returns a ``dns.rrset.RRset`` object.
    """

    return from_rdata_list(name, ttl, rdatas)