109 lines
3.5 KiB
Python
109 lines
3.5 KiB
Python
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
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# Copyright (C) 2006-2017 Nominum, Inc.
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#
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# Permission to use, copy, modify, and distribute this software and its
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# documentation for any purpose with or without fee is hereby granted,
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# provided that the above copyright notice and this permission notice
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# appear in all copies.
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#
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# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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"""TXT-like base class."""
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from typing import Any, Dict, Iterable, Optional, Tuple, Union
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import struct
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import dns.exception
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import dns.immutable
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import dns.rdata
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import dns.tokenizer
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@dns.immutable.immutable
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class TXTBase(dns.rdata.Rdata):
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"""Base class for rdata that is like a TXT record (see RFC 1035)."""
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__slots__ = ["strings"]
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def __init__(
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self,
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rdclass: dns.rdataclass.RdataClass,
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rdtype: dns.rdatatype.RdataType,
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strings: Iterable[Union[bytes, str]],
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):
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"""Initialize a TXT-like rdata.
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*rdclass*, an ``int`` is the rdataclass of the Rdata.
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*rdtype*, an ``int`` is the rdatatype of the Rdata.
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*strings*, a tuple of ``bytes``
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"""
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super().__init__(rdclass, rdtype)
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self.strings: Tuple[bytes] = self._as_tuple(
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strings, lambda x: self._as_bytes(x, True, 255)
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)
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def to_text(
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self,
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origin: Optional[dns.name.Name] = None,
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relativize: bool = True,
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**kw: Dict[str, Any]
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) -> str:
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txt = ""
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prefix = ""
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for s in self.strings:
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txt += '{}"{}"'.format(prefix, dns.rdata._escapify(s))
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prefix = " "
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return txt
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@classmethod
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def from_text(
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cls,
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rdclass: dns.rdataclass.RdataClass,
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rdtype: dns.rdatatype.RdataType,
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tok: dns.tokenizer.Tokenizer,
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origin: Optional[dns.name.Name] = None,
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relativize: bool = True,
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relativize_to: Optional[dns.name.Name] = None,
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) -> dns.rdata.Rdata:
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strings = []
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for token in tok.get_remaining():
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token = token.unescape_to_bytes()
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# The 'if' below is always true in the current code, but we
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# are leaving this check in in case things change some day.
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if not (
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token.is_quoted_string() or token.is_identifier()
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): # pragma: no cover
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raise dns.exception.SyntaxError("expected a string")
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if len(token.value) > 255:
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raise dns.exception.SyntaxError("string too long")
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strings.append(token.value)
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if len(strings) == 0:
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raise dns.exception.UnexpectedEnd
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return cls(rdclass, rdtype, strings)
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def _to_wire(self, file, compress=None, origin=None, canonicalize=False):
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for s in self.strings:
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l = len(s)
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assert l < 256
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file.write(struct.pack("!B", l))
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file.write(s)
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@classmethod
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def from_wire_parser(cls, rdclass, rdtype, parser, origin=None):
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strings = []
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while parser.remaining() > 0:
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s = parser.get_counted_bytes()
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strings.append(s)
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return cls(rdclass, rdtype, strings)
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