165 lines
4.7 KiB
Python
165 lines
4.7 KiB
Python
# This file is dual licensed under the terms of the Apache License, Version
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
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# for complete details.
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from __future__ import absolute_import, division, print_function
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import abc
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import binascii
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import inspect
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import sys
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import warnings
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# We use a UserWarning subclass, instead of DeprecationWarning, because CPython
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# decided deprecation warnings should be invisble by default.
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class CryptographyDeprecationWarning(UserWarning):
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pass
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# Several APIs were deprecated with no specific end-of-life date because of the
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# ubiquity of their use. They should not be removed until we agree on when that
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# cycle ends.
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PersistentlyDeprecated = CryptographyDeprecationWarning
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DeprecatedIn21 = CryptographyDeprecationWarning
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DeprecatedIn23 = CryptographyDeprecationWarning
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def _check_bytes(name, value):
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if not isinstance(value, bytes):
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raise TypeError("{0} must be bytes".format(name))
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def read_only_property(name):
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return property(lambda self: getattr(self, name))
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def register_interface(iface):
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def register_decorator(klass):
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verify_interface(iface, klass)
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iface.register(klass)
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return klass
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return register_decorator
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def register_interface_if(predicate, iface):
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def register_decorator(klass):
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if predicate:
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verify_interface(iface, klass)
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iface.register(klass)
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return klass
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return register_decorator
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if hasattr(int, "from_bytes"):
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int_from_bytes = int.from_bytes
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else:
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def int_from_bytes(data, byteorder, signed=False):
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assert byteorder == 'big'
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assert not signed
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return int(binascii.hexlify(data), 16)
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if hasattr(int, "to_bytes"):
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def int_to_bytes(integer, length=None):
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return integer.to_bytes(
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length or (integer.bit_length() + 7) // 8 or 1, 'big'
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)
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else:
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def int_to_bytes(integer, length=None):
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hex_string = '%x' % integer
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if length is None:
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n = len(hex_string)
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else:
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n = length * 2
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return binascii.unhexlify(hex_string.zfill(n + (n & 1)))
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class InterfaceNotImplemented(Exception):
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pass
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if hasattr(inspect, "signature"):
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signature = inspect.signature
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else:
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signature = inspect.getargspec
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def verify_interface(iface, klass):
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for method in iface.__abstractmethods__:
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if not hasattr(klass, method):
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raise InterfaceNotImplemented(
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"{0} is missing a {1!r} method".format(klass, method)
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)
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if isinstance(getattr(iface, method), abc.abstractproperty):
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# Can't properly verify these yet.
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continue
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sig = signature(getattr(iface, method))
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actual = signature(getattr(klass, method))
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if sig != actual:
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raise InterfaceNotImplemented(
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"{0}.{1}'s signature differs from the expected. Expected: "
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"{2!r}. Received: {3!r}".format(
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klass, method, sig, actual
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)
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)
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# No longer needed as of 2.2, but retained because we have external consumers
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# who use it.
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def bit_length(x):
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return x.bit_length()
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class _DeprecatedValue(object):
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def __init__(self, value, message, warning_class):
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self.value = value
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self.message = message
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self.warning_class = warning_class
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class _ModuleWithDeprecations(object):
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def __init__(self, module):
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self.__dict__["_module"] = module
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def __getattr__(self, attr):
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obj = getattr(self._module, attr)
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if isinstance(obj, _DeprecatedValue):
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warnings.warn(obj.message, obj.warning_class, stacklevel=2)
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obj = obj.value
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return obj
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def __setattr__(self, attr, value):
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setattr(self._module, attr, value)
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def __delattr__(self, attr):
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obj = getattr(self._module, attr)
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if isinstance(obj, _DeprecatedValue):
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warnings.warn(obj.message, obj.warning_class, stacklevel=2)
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delattr(self._module, attr)
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def __dir__(self):
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return ["_module"] + dir(self._module)
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def deprecated(value, module_name, message, warning_class):
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module = sys.modules[module_name]
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if not isinstance(module, _ModuleWithDeprecations):
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sys.modules[module_name] = _ModuleWithDeprecations(module)
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return _DeprecatedValue(value, message, warning_class)
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def cached_property(func):
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cached_name = "_cached_{0}".format(func)
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sentinel = object()
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def inner(instance):
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cache = getattr(instance, cached_name, sentinel)
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if cache is not sentinel:
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return cache
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result = func(instance)
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setattr(instance, cached_name, result)
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return result
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return property(inner)
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