sqlmap/thirdparty/oset/_abc.py
2019-03-21 14:00:09 +01:00

477 lines
14 KiB
Python

#!/usr/bin/env python2
# -*- mode:python; tab-width: 2; coding: utf-8 -*-
"""Partially backported python ABC classes"""
from __future__ import absolute_import
import sys
import types
if sys.version_info > (2, 6):
raise ImportError("Use native ABC classes istead of this one.")
# Instance of old-style class
class _C:
pass
_InstanceType = type(_C())
def abstractmethod(funcobj):
"""A decorator indicating abstract methods.
Requires that the metaclass is ABCMeta or derived from it. A
class that has a metaclass derived from ABCMeta cannot be
instantiated unless all of its abstract methods are overridden.
The abstract methods can be called using any of the normal
'super' call mechanisms.
Usage:
class C:
__metaclass__ = ABCMeta
@abstractmethod
def my_abstract_method(self, ...):
...
"""
funcobj.__isabstractmethod__ = True
return funcobj
class ABCMeta(type):
"""Metaclass for defining Abstract Base Classes (ABCs).
Use this metaclass to create an ABC. An ABC can be subclassed
directly, and then acts as a mix-in class. You can also register
unrelated concrete classes (even built-in classes) and unrelated
ABCs as 'virtual subclasses' -- these and their descendants will
be considered subclasses of the registering ABC by the built-in
issubclass() function, but the registering ABC won't show up in
their MRO (Method Resolution Order) nor will method
implementations defined by the registering ABC be callable (not
even via super()).
"""
# A global counter that is incremented each time a class is
# registered as a virtual subclass of anything. It forces the
# negative cache to be cleared before its next use.
_abc_invalidation_counter = 0
def __new__(mcls, name, bases, namespace):
cls = super(ABCMeta, mcls).__new__(mcls, name, bases, namespace)
# Compute set of abstract method names
abstracts = set(name
for name, value in namespace.items()
if getattr(value, "__isabstractmethod__", False))
for base in bases:
for name in getattr(base, "__abstractmethods__", set()):
value = getattr(cls, name, None)
if getattr(value, "__isabstractmethod__", False):
abstracts.add(name)
cls.__abstractmethods__ = frozenset(abstracts)
# Set up inheritance registry
cls._abc_registry = set()
cls._abc_cache = set()
cls._abc_negative_cache = set()
cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
return cls
def register(cls, subclass):
"""Register a virtual subclass of an ABC."""
if not isinstance(subclass, (type, types.ClassType)):
raise TypeError("Can only register classes")
if issubclass(subclass, cls):
return # Already a subclass
# Subtle: test for cycles *after* testing for "already a subclass";
# this means we allow X.register(X) and interpret it as a no-op.
if issubclass(cls, subclass):
# This would create a cycle, which is bad for the algorithm below
raise RuntimeError("Refusing to create an inheritance cycle")
cls._abc_registry.add(subclass)
ABCMeta._abc_invalidation_counter += 1 # Invalidate negative cache
def _dump_registry(cls, file=None):
"""Debug helper to print the ABC registry."""
print >> file, "Class: %s.%s" % (cls.__module__, cls.__name__)
print >> file, "Inv.counter: %s" % ABCMeta._abc_invalidation_counter
for name in sorted(cls.__dict__.keys()):
if name.startswith("_abc_"):
value = getattr(cls, name)
print >> file, "%s: %r" % (name, value)
def __instancecheck__(cls, instance):
"""Override for isinstance(instance, cls)."""
# Inline the cache checking when it's simple.
subclass = getattr(instance, '__class__', None)
if subclass in cls._abc_cache:
return True
subtype = type(instance)
# Old-style instances
if subtype is _InstanceType:
subtype = subclass
if subtype is subclass or subclass is None:
if (cls._abc_negative_cache_version ==
ABCMeta._abc_invalidation_counter and
subtype in cls._abc_negative_cache):
return False
# Fall back to the subclass check.
return cls.__subclasscheck__(subtype)
return (cls.__subclasscheck__(subclass) or
cls.__subclasscheck__(subtype))
def __subclasscheck__(cls, subclass):
"""Override for issubclass(subclass, cls)."""
# Check cache
if subclass in cls._abc_cache:
return True
# Check negative cache; may have to invalidate
if cls._abc_negative_cache_version < ABCMeta._abc_invalidation_counter:
# Invalidate the negative cache
cls._abc_negative_cache = set()
cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
elif subclass in cls._abc_negative_cache:
return False
# Check the subclass hook
ok = cls.__subclasshook__(subclass)
if ok is not NotImplemented:
assert isinstance(ok, bool)
if ok:
cls._abc_cache.add(subclass)
else:
cls._abc_negative_cache.add(subclass)
return ok
# Check if it's a direct subclass
if cls in getattr(subclass, '__mro__', ()):
cls._abc_cache.add(subclass)
return True
# Check if it's a subclass of a registered class (recursive)
for rcls in cls._abc_registry:
if issubclass(subclass, rcls):
cls._abc_cache.add(subclass)
return True
# Check if it's a subclass of a subclass (recursive)
for scls in cls.__subclasses__():
if issubclass(subclass, scls):
cls._abc_cache.add(subclass)
return True
# No dice; update negative cache
cls._abc_negative_cache.add(subclass)
return False
def _hasattr(C, attr):
try:
return any(attr in B.__dict__ for B in C.__mro__)
except AttributeError:
# Old-style class
return hasattr(C, attr)
class Sized:
__metaclass__ = ABCMeta
@abstractmethod
def __len__(self):
return 0
@classmethod
def __subclasshook__(cls, C):
if cls is Sized:
if _hasattr(C, "__len__"):
return True
return NotImplemented
class Container:
__metaclass__ = ABCMeta
@abstractmethod
def __contains__(self, x):
return False
@classmethod
def __subclasshook__(cls, C):
if cls is Container:
if _hasattr(C, "__contains__"):
return True
return NotImplemented
class Iterable:
__metaclass__ = ABCMeta
@abstractmethod
def __iter__(self):
while False:
yield None
@classmethod
def __subclasshook__(cls, C):
if cls is Iterable:
if _hasattr(C, "__iter__"):
return True
return NotImplemented
Iterable.register(str)
class Set(Sized, Iterable, Container):
"""A set is a finite, iterable container.
This class provides concrete generic implementations of all
methods except for __contains__, __iter__ and __len__.
To override the comparisons (presumably for speed, as the
semantics are fixed), all you have to do is redefine __le__ and
then the other operations will automatically follow suit.
"""
def __le__(self, other):
if not isinstance(other, Set):
return NotImplemented
if len(self) > len(other):
return False
for elem in self:
if elem not in other:
return False
return True
def __lt__(self, other):
if not isinstance(other, Set):
return NotImplemented
return len(self) < len(other) and self.__le__(other)
def __gt__(self, other):
if not isinstance(other, Set):
return NotImplemented
return other < self
def __ge__(self, other):
if not isinstance(other, Set):
return NotImplemented
return other <= self
def __eq__(self, other):
if not isinstance(other, Set):
return NotImplemented
return len(self) == len(other) and self.__le__(other)
def __ne__(self, other):
return not (self == other)
@classmethod
def _from_iterable(cls, it):
'''Construct an instance of the class from any iterable input.
Must override this method if the class constructor signature
does not accept an iterable for an input.
'''
return cls(it)
def __and__(self, other):
if not isinstance(other, Iterable):
return NotImplemented
return self._from_iterable(value for value in other if value in self)
def isdisjoint(self, other):
for value in other:
if value in self:
return False
return True
def __or__(self, other):
if not isinstance(other, Iterable):
return NotImplemented
chain = (e for s in (self, other) for e in s)
return self._from_iterable(chain)
def __sub__(self, other):
if not isinstance(other, Set):
if not isinstance(other, Iterable):
return NotImplemented
other = self._from_iterable(other)
return self._from_iterable(value for value in self
if value not in other)
def __xor__(self, other):
if not isinstance(other, Set):
if not isinstance(other, Iterable):
return NotImplemented
other = self._from_iterable(other)
return (self - other) | (other - self)
# Sets are not hashable by default, but subclasses can change this
__hash__ = None
def _hash(self):
"""Compute the hash value of a set.
Note that we don't define __hash__: not all sets are hashable.
But if you define a hashable set type, its __hash__ should
call this function.
This must be compatible __eq__.
All sets ought to compare equal if they contain the same
elements, regardless of how they are implemented, and
regardless of the order of the elements; so there's not much
freedom for __eq__ or __hash__. We match the algorithm used
by the built-in frozenset type.
"""
MAX = sys.maxint
MASK = 2 * MAX + 1
n = len(self)
h = 1927868237 * (n + 1)
h &= MASK
for x in self:
hx = hash(x)
h ^= (hx ^ (hx << 16) ^ 89869747) * 3644798167
h &= MASK
h = h * 69069 + 907133923
h &= MASK
if h > MAX:
h -= MASK + 1
if h == -1:
h = 590923713
return h
Set.register(frozenset)
class MutableSet(Set):
@abstractmethod
def add(self, value):
"""Add an element."""
raise NotImplementedError
@abstractmethod
def discard(self, value):
"""Remove an element. Do not raise an exception if absent."""
raise NotImplementedError
def remove(self, value):
"""Remove an element. If not a member, raise a KeyError."""
if value not in self:
raise KeyError(value)
self.discard(value)
def pop(self):
"""Return the popped value. Raise KeyError if empty."""
it = iter(self)
try:
value = next(it)
except StopIteration:
raise KeyError
self.discard(value)
return value
def clear(self):
"""This is slow (creates N new iterators!) but effective."""
try:
while True:
self.pop()
except KeyError:
pass
def __ior__(self, it):
for value in it:
self.add(value)
return self
def __iand__(self, it):
for value in (self - it):
self.discard(value)
return self
def __ixor__(self, it):
if not isinstance(it, Set):
it = self._from_iterable(it)
for value in it:
if value in self:
self.discard(value)
else:
self.add(value)
return self
def __isub__(self, it):
for value in it:
self.discard(value)
return self
MutableSet.register(set)
class OrderedSet(MutableSet):
def __init__(self, iterable=None):
self.end = end = []
end += [None, end, end] # sentinel node for doubly linked list
self.map = {} # key --> [key, prev, next]
if iterable is not None:
self |= iterable
def __len__(self):
return len(self.map)
def __contains__(self, key):
return key in self.map
def __getitem__(self, key):
return list(self)[key]
def add(self, key):
if key not in self.map:
end = self.end
curr = end[PREV]
curr[NEXT] = end[PREV] = self.map[key] = [key, curr, end]
def discard(self, key):
if key in self.map:
key, prev, next = self.map.pop(key)
prev[NEXT] = next
next[PREV] = prev
def __iter__(self):
end = self.end
curr = end[NEXT]
while curr is not end:
yield curr[KEY]
curr = curr[NEXT]
def __reversed__(self):
end = self.end
curr = end[PREV]
while curr is not end:
yield curr[KEY]
curr = curr[PREV]
def pop(self, last=True):
if not self:
raise KeyError('set is empty')
key = next(reversed(self)) if last else next(iter(self))
self.discard(key)
return key
def __repr__(self):
if not self:
return '%s()' % (self.__class__.__name__,)
return '%s(%r)' % (self.__class__.__name__, list(self))
def __eq__(self, other):
if isinstance(other, OrderedSet):
return len(self) == len(other) and list(self) == list(other)
return set(self) == set(other)
def __del__(self):
if all([KEY, PREV, NEXT]):
self.clear() # remove circular references
if __name__ == '__main__':
print(OrderedSet('abracadaba'))
print(OrderedSet('simsalabim'))