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749 lines
19 KiB
Python
749 lines
19 KiB
Python
# Copyright 2007 Google, Inc. All Rights Reserved.
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# Licensed to PSF under a Contributor Agreement.
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"""Abstract Base Classes (ABCs) for collections, according to PEP 3119.
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Unit tests are in test_collections.
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"""
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from abc import ABCMeta, abstractmethod
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import sys
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__all__ = ["Hashable", "Iterable", "Iterator",
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"Sized", "Container", "Callable",
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"Set", "MutableSet",
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"Mapping", "MutableMapping",
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"MappingView", "KeysView", "ItemsView", "ValuesView",
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"Sequence", "MutableSequence",
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"ByteString",
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]
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# This module has been renamed from collections.abc to _collections_abc to
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# speed up interpreter startup. Some of the types such as MutableMapping are
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# required early but collections module imports a lot of other modules.
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# See issue #19218
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__name__ = "collections.abc"
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# Private list of types that we want to register with the various ABCs
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# so that they will pass tests like:
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# it = iter(somebytearray)
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# assert isinstance(it, Iterable)
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# Note: in other implementations, these types many not be distinct
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# and they make have their own implementation specific types that
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# are not included on this list.
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bytes_iterator = type(iter(b''))
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bytearray_iterator = type(iter(bytearray()))
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#callable_iterator = ???
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dict_keyiterator = type(iter({}.keys()))
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dict_valueiterator = type(iter({}.values()))
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dict_itemiterator = type(iter({}.items()))
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list_iterator = type(iter([]))
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list_reverseiterator = type(iter(reversed([])))
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range_iterator = type(iter(range(0)))
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set_iterator = type(iter(set()))
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str_iterator = type(iter(""))
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tuple_iterator = type(iter(()))
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zip_iterator = type(iter(zip()))
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## views ##
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dict_keys = type({}.keys())
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dict_values = type({}.values())
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dict_items = type({}.items())
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## misc ##
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mappingproxy = type(type.__dict__)
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### ONE-TRICK PONIES ###
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class Hashable(metaclass=ABCMeta):
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__slots__ = ()
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@abstractmethod
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def __hash__(self):
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return 0
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@classmethod
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def __subclasshook__(cls, C):
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if cls is Hashable:
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for B in C.__mro__:
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if "__hash__" in B.__dict__:
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if B.__dict__["__hash__"]:
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return True
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break
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return NotImplemented
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class Iterable(metaclass=ABCMeta):
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__slots__ = ()
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@abstractmethod
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def __iter__(self):
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while False:
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yield None
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@classmethod
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def __subclasshook__(cls, C):
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if cls is Iterable:
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if any("__iter__" in B.__dict__ for B in C.__mro__):
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return True
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return NotImplemented
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class Iterator(Iterable):
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__slots__ = ()
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@abstractmethod
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def __next__(self):
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'Return the next item from the iterator. When exhausted, raise StopIteration'
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raise StopIteration
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def __iter__(self):
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return self
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@classmethod
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def __subclasshook__(cls, C):
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if cls is Iterator:
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if (any("__next__" in B.__dict__ for B in C.__mro__) and
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any("__iter__" in B.__dict__ for B in C.__mro__)):
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return True
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return NotImplemented
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Iterator.register(bytes_iterator)
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Iterator.register(bytearray_iterator)
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#Iterator.register(callable_iterator)
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Iterator.register(dict_keyiterator)
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Iterator.register(dict_valueiterator)
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Iterator.register(dict_itemiterator)
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Iterator.register(list_iterator)
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Iterator.register(list_reverseiterator)
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Iterator.register(range_iterator)
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Iterator.register(set_iterator)
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Iterator.register(str_iterator)
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Iterator.register(tuple_iterator)
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Iterator.register(zip_iterator)
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class Sized(metaclass=ABCMeta):
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__slots__ = ()
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@abstractmethod
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def __len__(self):
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return 0
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@classmethod
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def __subclasshook__(cls, C):
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if cls is Sized:
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if any("__len__" in B.__dict__ for B in C.__mro__):
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return True
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return NotImplemented
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class Container(metaclass=ABCMeta):
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__slots__ = ()
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@abstractmethod
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def __contains__(self, x):
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return False
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@classmethod
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def __subclasshook__(cls, C):
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if cls is Container:
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if any("__contains__" in B.__dict__ for B in C.__mro__):
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return True
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return NotImplemented
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class Callable(metaclass=ABCMeta):
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__slots__ = ()
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@abstractmethod
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def __call__(self, *args, **kwds):
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return False
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@classmethod
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def __subclasshook__(cls, C):
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if cls is Callable:
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if any("__call__" in B.__dict__ for B in C.__mro__):
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return True
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return NotImplemented
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### SETS ###
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class Set(Sized, Iterable, Container):
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"""A set is a finite, iterable container.
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This class provides concrete generic implementations of all
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methods except for __contains__, __iter__ and __len__.
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To override the comparisons (presumably for speed, as the
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semantics are fixed), redefine __le__ and __ge__,
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then the other operations will automatically follow suit.
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"""
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__slots__ = ()
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def __le__(self, other):
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if not isinstance(other, Set):
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return NotImplemented
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if len(self) > len(other):
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return False
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for elem in self:
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if elem not in other:
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return False
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return True
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def __lt__(self, other):
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if not isinstance(other, Set):
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return NotImplemented
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return len(self) < len(other) and self.__le__(other)
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def __gt__(self, other):
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if not isinstance(other, Set):
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return NotImplemented
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return len(self) > len(other) and self.__ge__(other)
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def __ge__(self, other):
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if not isinstance(other, Set):
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return NotImplemented
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if len(self) < len(other):
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return False
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for elem in other:
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if elem not in self:
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return False
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return True
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def __eq__(self, other):
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if not isinstance(other, Set):
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return NotImplemented
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return len(self) == len(other) and self.__le__(other)
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@classmethod
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def _from_iterable(cls, it):
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'''Construct an instance of the class from any iterable input.
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Must override this method if the class constructor signature
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does not accept an iterable for an input.
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'''
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return cls(it)
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def __and__(self, other):
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if not isinstance(other, Iterable):
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return NotImplemented
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return self._from_iterable(value for value in other if value in self)
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__rand__ = __and__
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def isdisjoint(self, other):
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'Return True if two sets have a null intersection.'
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for value in other:
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if value in self:
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return False
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return True
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def __or__(self, other):
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if not isinstance(other, Iterable):
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return NotImplemented
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chain = (e for s in (self, other) for e in s)
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return self._from_iterable(chain)
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__ror__ = __or__
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def __sub__(self, other):
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if not isinstance(other, Set):
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if not isinstance(other, Iterable):
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return NotImplemented
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other = self._from_iterable(other)
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return self._from_iterable(value for value in self
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if value not in other)
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def __rsub__(self, other):
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if not isinstance(other, Set):
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if not isinstance(other, Iterable):
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return NotImplemented
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other = self._from_iterable(other)
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return self._from_iterable(value for value in other
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if value not in self)
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def __xor__(self, other):
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if not isinstance(other, Set):
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if not isinstance(other, Iterable):
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return NotImplemented
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other = self._from_iterable(other)
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return (self - other) | (other - self)
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__rxor__ = __xor__
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def _hash(self):
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"""Compute the hash value of a set.
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Note that we don't define __hash__: not all sets are hashable.
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But if you define a hashable set type, its __hash__ should
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call this function.
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This must be compatible __eq__.
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All sets ought to compare equal if they contain the same
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elements, regardless of how they are implemented, and
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regardless of the order of the elements; so there's not much
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freedom for __eq__ or __hash__. We match the algorithm used
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by the built-in frozenset type.
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"""
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MAX = sys.maxsize
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MASK = 2 * MAX + 1
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n = len(self)
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h = 1927868237 * (n + 1)
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h &= MASK
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for x in self:
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hx = hash(x)
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h ^= (hx ^ (hx << 16) ^ 89869747) * 3644798167
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h &= MASK
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h = h * 69069 + 907133923
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h &= MASK
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if h > MAX:
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h -= MASK + 1
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if h == -1:
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h = 590923713
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return h
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Set.register(frozenset)
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class MutableSet(Set):
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"""A mutable set is a finite, iterable container.
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This class provides concrete generic implementations of all
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methods except for __contains__, __iter__, __len__,
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add(), and discard().
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To override the comparisons (presumably for speed, as the
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semantics are fixed), all you have to do is redefine __le__ and
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then the other operations will automatically follow suit.
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"""
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__slots__ = ()
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@abstractmethod
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def add(self, value):
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"""Add an element."""
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raise NotImplementedError
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@abstractmethod
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def discard(self, value):
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"""Remove an element. Do not raise an exception if absent."""
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raise NotImplementedError
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def remove(self, value):
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"""Remove an element. If not a member, raise a KeyError."""
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if value not in self:
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raise KeyError(value)
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self.discard(value)
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def pop(self):
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"""Return the popped value. Raise KeyError if empty."""
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it = iter(self)
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try:
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value = next(it)
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except StopIteration:
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raise KeyError
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self.discard(value)
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return value
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def clear(self):
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"""This is slow (creates N new iterators!) but effective."""
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try:
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while True:
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self.pop()
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except KeyError:
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pass
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def __ior__(self, it):
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for value in it:
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self.add(value)
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return self
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def __iand__(self, it):
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for value in (self - it):
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self.discard(value)
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return self
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def __ixor__(self, it):
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if it is self:
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self.clear()
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else:
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if not isinstance(it, Set):
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it = self._from_iterable(it)
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for value in it:
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if value in self:
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self.discard(value)
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else:
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self.add(value)
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return self
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def __isub__(self, it):
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if it is self:
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self.clear()
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else:
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for value in it:
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self.discard(value)
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return self
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MutableSet.register(set)
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### MAPPINGS ###
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class Mapping(Sized, Iterable, Container):
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__slots__ = ()
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"""A Mapping is a generic container for associating key/value
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pairs.
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This class provides concrete generic implementations of all
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methods except for __getitem__, __iter__, and __len__.
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"""
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@abstractmethod
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def __getitem__(self, key):
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raise KeyError
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def get(self, key, default=None):
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'D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None.'
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try:
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return self[key]
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except KeyError:
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return default
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def __contains__(self, key):
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try:
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self[key]
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except KeyError:
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return False
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else:
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return True
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def keys(self):
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"D.keys() -> a set-like object providing a view on D's keys"
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return KeysView(self)
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def items(self):
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"D.items() -> a set-like object providing a view on D's items"
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return ItemsView(self)
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def values(self):
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"D.values() -> an object providing a view on D's values"
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return ValuesView(self)
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def __eq__(self, other):
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if not isinstance(other, Mapping):
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return NotImplemented
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return dict(self.items()) == dict(other.items())
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Mapping.register(mappingproxy)
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class MappingView(Sized):
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def __init__(self, mapping):
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self._mapping = mapping
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def __len__(self):
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return len(self._mapping)
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def __repr__(self):
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return '{0.__class__.__name__}({0._mapping!r})'.format(self)
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class KeysView(MappingView, Set):
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@classmethod
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def _from_iterable(self, it):
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return set(it)
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def __contains__(self, key):
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return key in self._mapping
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def __iter__(self):
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yield from self._mapping
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KeysView.register(dict_keys)
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class ItemsView(MappingView, Set):
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@classmethod
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def _from_iterable(self, it):
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return set(it)
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def __contains__(self, item):
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key, value = item
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try:
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v = self._mapping[key]
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except KeyError:
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return False
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else:
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return v == value
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def __iter__(self):
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for key in self._mapping:
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yield (key, self._mapping[key])
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ItemsView.register(dict_items)
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class ValuesView(MappingView):
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def __contains__(self, value):
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for key in self._mapping:
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if value == self._mapping[key]:
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return True
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return False
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def __iter__(self):
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for key in self._mapping:
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yield self._mapping[key]
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ValuesView.register(dict_values)
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class MutableMapping(Mapping):
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__slots__ = ()
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"""A MutableMapping is a generic container for associating
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key/value pairs.
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This class provides concrete generic implementations of all
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methods except for __getitem__, __setitem__, __delitem__,
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__iter__, and __len__.
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"""
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@abstractmethod
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def __setitem__(self, key, value):
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raise KeyError
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@abstractmethod
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def __delitem__(self, key):
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raise KeyError
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__marker = object()
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def pop(self, key, default=__marker):
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'''D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
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If key is not found, d is returned if given, otherwise KeyError is raised.
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'''
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try:
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value = self[key]
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except KeyError:
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if default is self.__marker:
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raise
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return default
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else:
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del self[key]
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return value
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def popitem(self):
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'''D.popitem() -> (k, v), remove and return some (key, value) pair
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as a 2-tuple; but raise KeyError if D is empty.
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'''
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try:
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key = next(iter(self))
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except StopIteration:
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raise KeyError
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value = self[key]
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del self[key]
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return key, value
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def clear(self):
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'D.clear() -> None. Remove all items from D.'
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try:
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while True:
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self.popitem()
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except KeyError:
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pass
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def update(*args, **kwds):
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''' D.update([E, ]**F) -> None. Update D from mapping/iterable E and F.
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If E present and has a .keys() method, does: for k in E: D[k] = E[k]
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If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v
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In either case, this is followed by: for k, v in F.items(): D[k] = v
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'''
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if not args:
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raise TypeError("descriptor 'update' of 'MutableMapping' object "
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"needs an argument")
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self, *args = args
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if len(args) > 1:
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raise TypeError('update expected at most 1 arguments, got %d' %
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len(args))
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if args:
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other = args[0]
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if isinstance(other, Mapping):
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for key in other:
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self[key] = other[key]
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elif hasattr(other, "keys"):
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for key in other.keys():
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self[key] = other[key]
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else:
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for key, value in other:
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self[key] = value
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for key, value in kwds.items():
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self[key] = value
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def setdefault(self, key, default=None):
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'D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D'
|
|
try:
|
|
return self[key]
|
|
except KeyError:
|
|
self[key] = default
|
|
return default
|
|
|
|
MutableMapping.register(dict)
|
|
|
|
|
|
### SEQUENCES ###
|
|
|
|
|
|
class Sequence(Sized, Iterable, Container):
|
|
|
|
"""All the operations on a read-only sequence.
|
|
|
|
Concrete subclasses must override __new__ or __init__,
|
|
__getitem__, and __len__.
|
|
"""
|
|
|
|
__slots__ = ()
|
|
|
|
@abstractmethod
|
|
def __getitem__(self, index):
|
|
raise IndexError
|
|
|
|
def __iter__(self):
|
|
i = 0
|
|
try:
|
|
while True:
|
|
v = self[i]
|
|
yield v
|
|
i += 1
|
|
except IndexError:
|
|
return
|
|
|
|
def __contains__(self, value):
|
|
for v in self:
|
|
if v == value:
|
|
return True
|
|
return False
|
|
|
|
def __reversed__(self):
|
|
for i in reversed(range(len(self))):
|
|
yield self[i]
|
|
|
|
def index(self, value):
|
|
'''S.index(value) -> integer -- return first index of value.
|
|
Raises ValueError if the value is not present.
|
|
'''
|
|
for i, v in enumerate(self):
|
|
if v == value:
|
|
return i
|
|
raise ValueError
|
|
|
|
def count(self, value):
|
|
'S.count(value) -> integer -- return number of occurrences of value'
|
|
return sum(1 for v in self if v == value)
|
|
|
|
Sequence.register(tuple)
|
|
Sequence.register(str)
|
|
Sequence.register(range)
|
|
Sequence.register(memoryview)
|
|
|
|
|
|
class ByteString(Sequence):
|
|
|
|
"""This unifies bytes and bytearray.
|
|
|
|
XXX Should add all their methods.
|
|
"""
|
|
|
|
__slots__ = ()
|
|
|
|
ByteString.register(bytes)
|
|
ByteString.register(bytearray)
|
|
|
|
|
|
class MutableSequence(Sequence):
|
|
|
|
__slots__ = ()
|
|
|
|
"""All the operations on a read-write sequence.
|
|
|
|
Concrete subclasses must provide __new__ or __init__,
|
|
__getitem__, __setitem__, __delitem__, __len__, and insert().
|
|
|
|
"""
|
|
|
|
@abstractmethod
|
|
def __setitem__(self, index, value):
|
|
raise IndexError
|
|
|
|
@abstractmethod
|
|
def __delitem__(self, index):
|
|
raise IndexError
|
|
|
|
@abstractmethod
|
|
def insert(self, index, value):
|
|
'S.insert(index, value) -- insert value before index'
|
|
raise IndexError
|
|
|
|
def append(self, value):
|
|
'S.append(value) -- append value to the end of the sequence'
|
|
self.insert(len(self), value)
|
|
|
|
def clear(self):
|
|
'S.clear() -> None -- remove all items from S'
|
|
try:
|
|
while True:
|
|
self.pop()
|
|
except IndexError:
|
|
pass
|
|
|
|
def reverse(self):
|
|
'S.reverse() -- reverse *IN PLACE*'
|
|
n = len(self)
|
|
for i in range(n//2):
|
|
self[i], self[n-i-1] = self[n-i-1], self[i]
|
|
|
|
def extend(self, values):
|
|
'S.extend(iterable) -- extend sequence by appending elements from the iterable'
|
|
for v in values:
|
|
self.append(v)
|
|
|
|
def pop(self, index=-1):
|
|
'''S.pop([index]) -> item -- remove and return item at index (default last).
|
|
Raise IndexError if list is empty or index is out of range.
|
|
'''
|
|
v = self[index]
|
|
del self[index]
|
|
return v
|
|
|
|
def remove(self, value):
|
|
'''S.remove(value) -- remove first occurrence of value.
|
|
Raise ValueError if the value is not present.
|
|
'''
|
|
del self[self.index(value)]
|
|
|
|
def __iadd__(self, values):
|
|
self.extend(values)
|
|
return self
|
|
|
|
MutableSequence.register(list)
|
|
MutableSequence.register(bytearray) # Multiply inheriting, see ByteString
|