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- # 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.
-
- """Common DNS Exceptions.
-
- Dnspython modules may also define their own exceptions, which will
- always be subclasses of ``DNSException``.
- """
-
-
- from typing import Optional, Set
-
-
- class DNSException(Exception):
- """Abstract base class shared by all dnspython exceptions.
-
- It supports two basic modes of operation:
-
- a) Old/compatible mode is used if ``__init__`` was called with
- empty *kwargs*. In compatible mode all *args* are passed
- to the standard Python Exception class as before and all *args* are
- printed by the standard ``__str__`` implementation. Class variable
- ``msg`` (or doc string if ``msg`` is ``None``) is returned from ``str()``
- if *args* is empty.
-
- b) New/parametrized mode is used if ``__init__`` was called with
- non-empty *kwargs*.
- In the new mode *args* must be empty and all kwargs must match
- those set in class variable ``supp_kwargs``. All kwargs are stored inside
- ``self.kwargs`` and used in a new ``__str__`` implementation to construct
- a formatted message based on the ``fmt`` class variable, a ``string``.
-
- In the simplest case it is enough to override the ``supp_kwargs``
- and ``fmt`` class variables to get nice parametrized messages.
- """
-
- msg: Optional[str] = None # non-parametrized message
- supp_kwargs: Set[str] = set() # accepted parameters for _fmt_kwargs (sanity check)
- fmt: Optional[str] = None # message parametrized with results from _fmt_kwargs
-
- def __init__(self, *args, **kwargs):
- self._check_params(*args, **kwargs)
- if kwargs:
- # This call to a virtual method from __init__ is ok in our usage
- self.kwargs = self._check_kwargs(**kwargs) # lgtm[py/init-calls-subclass]
- self.msg = str(self)
- else:
- self.kwargs = dict() # defined but empty for old mode exceptions
- if self.msg is None:
- # doc string is better implicit message than empty string
- self.msg = self.__doc__
- if args:
- super().__init__(*args)
- else:
- super().__init__(self.msg)
-
- def _check_params(self, *args, **kwargs):
- """Old exceptions supported only args and not kwargs.
-
- For sanity we do not allow to mix old and new behavior."""
- if args or kwargs:
- assert bool(args) != bool(
- kwargs
- ), "keyword arguments are mutually exclusive with positional args"
-
- def _check_kwargs(self, **kwargs):
- if kwargs:
- assert (
- set(kwargs.keys()) == self.supp_kwargs
- ), f"following set of keyword args is required: {self.supp_kwargs}"
- return kwargs
-
- def _fmt_kwargs(self, **kwargs):
- """Format kwargs before printing them.
-
- Resulting dictionary has to have keys necessary for str.format call
- on fmt class variable.
- """
- fmtargs = {}
- for kw, data in kwargs.items():
- if isinstance(data, (list, set)):
- # convert list of <someobj> to list of str(<someobj>)
- fmtargs[kw] = list(map(str, data))
- if len(fmtargs[kw]) == 1:
- # remove list brackets [] from single-item lists
- fmtargs[kw] = fmtargs[kw].pop()
- else:
- fmtargs[kw] = data
- return fmtargs
-
- def __str__(self):
- if self.kwargs and self.fmt:
- # provide custom message constructed from keyword arguments
- fmtargs = self._fmt_kwargs(**self.kwargs)
- return self.fmt.format(**fmtargs)
- else:
- # print *args directly in the same way as old DNSException
- return super().__str__()
-
-
- class FormError(DNSException):
- """DNS message is malformed."""
-
-
- class SyntaxError(DNSException):
- """Text input is malformed."""
-
-
- class UnexpectedEnd(SyntaxError):
- """Text input ended unexpectedly."""
-
-
- class TooBig(DNSException):
- """The DNS message is too big."""
-
-
- class Timeout(DNSException):
- """The DNS operation timed out."""
-
- supp_kwargs = {"timeout"}
- fmt = "The DNS operation timed out after {timeout:.3f} seconds"
-
- # We do this as otherwise mypy complains about unexpected keyword argument
- # idna_exception
- def __init__(self, *args, **kwargs):
- super().__init__(*args, **kwargs)
-
-
- class UnsupportedAlgorithm(DNSException):
- """The DNSSEC algorithm is not supported."""
-
-
- class AlgorithmKeyMismatch(UnsupportedAlgorithm):
- """The DNSSEC algorithm is not supported for the given key type."""
-
-
- class ValidationFailure(DNSException):
- """The DNSSEC signature is invalid."""
-
-
- class DeniedByPolicy(DNSException):
- """Denied by DNSSEC policy."""
-
-
- class ExceptionWrapper:
- def __init__(self, exception_class):
- self.exception_class = exception_class
-
- def __enter__(self):
- return self
-
- def __exit__(self, exc_type, exc_val, exc_tb):
- if exc_type is not None and not isinstance(exc_val, self.exception_class):
- raise self.exception_class(str(exc_val)) from exc_val
- return False
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