Backport of weakref.WeakSet and tests from Python 3.

This commit is contained in:
Michael Foord 2010-03-29 20:04:23 +00:00
parent b8d688cd7c
commit e6410c536c
6 changed files with 602 additions and 1 deletions

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@ -209,6 +209,14 @@ methods of :class:`WeakKeyDictionary` objects.
.. versionadded:: 2.5 .. versionadded:: 2.5
.. class:: WeakSet([elements])
Set class that keeps weak references to its elements. An element will be
discarded when no strong reference to it exists any more.
.. versionadded:: 2.7
.. data:: ReferenceType .. data:: ReferenceType
The type object for weak references objects. The type object for weak references objects.

212
Lib/_weakrefset.py Normal file
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@ -0,0 +1,212 @@
# Access WeakSet through the weakref module.
# This code is separated-out because it is needed
# by abc.py to load everything else at startup.
from _weakref import ref
__all__ = ['WeakSet']
class _IterationGuard(object):
# This context manager registers itself in the current iterators of the
# weak container, such as to delay all removals until the context manager
# exits.
# This technique should be relatively thread-safe (since sets are).
def __init__(self, weakcontainer):
# Don't create cycles
self.weakcontainer = ref(weakcontainer)
def __enter__(self):
w = self.weakcontainer()
if w is not None:
w._iterating.add(self)
return self
def __exit__(self, e, t, b):
w = self.weakcontainer()
if w is not None:
s = w._iterating
s.remove(self)
if not s:
w._commit_removals()
class WeakSet(object):
def __init__(self, data=None):
self.data = set()
def _remove(item, selfref=ref(self)):
self = selfref()
if self is not None:
if self._iterating:
self._pending_removals.append(item)
else:
self.data.discard(item)
self._remove = _remove
# A list of keys to be removed
self._pending_removals = []
self._iterating = set()
if data is not None:
self.update(data)
def _commit_removals(self):
l = self._pending_removals
discard = self.data.discard
while l:
discard(l.pop())
def __iter__(self):
with _IterationGuard(self):
for itemref in self.data:
item = itemref()
if item is not None:
yield item
def __len__(self):
return sum(x() is not None for x in self.data)
def __contains__(self, item):
return ref(item) in self.data
def __reduce__(self):
return (self.__class__, (list(self),),
getattr(self, '__dict__', None))
__hash__ = None
def add(self, item):
if self._pending_removals:
self._commit_removals()
self.data.add(ref(item, self._remove))
def clear(self):
if self._pending_removals:
self._commit_removals()
self.data.clear()
def copy(self):
return self.__class__(self)
def pop(self):
if self._pending_removals:
self._commit_removals()
while True:
try:
itemref = self.data.pop()
except KeyError:
raise KeyError('pop from empty WeakSet')
item = itemref()
if item is not None:
return item
def remove(self, item):
if self._pending_removals:
self._commit_removals()
self.data.remove(ref(item))
def discard(self, item):
if self._pending_removals:
self._commit_removals()
self.data.discard(ref(item))
def update(self, other):
if self._pending_removals:
self._commit_removals()
if isinstance(other, self.__class__):
self.data.update(other.data)
else:
for element in other:
self.add(element)
def __ior__(self, other):
self.update(other)
return self
# Helper functions for simple delegating methods.
def _apply(self, other, method):
if not isinstance(other, self.__class__):
other = self.__class__(other)
newdata = method(other.data)
newset = self.__class__()
newset.data = newdata
return newset
def difference(self, other):
return self._apply(other, self.data.difference)
__sub__ = difference
def difference_update(self, other):
if self._pending_removals:
self._commit_removals()
if self is other:
self.data.clear()
else:
self.data.difference_update(ref(item) for item in other)
def __isub__(self, other):
if self._pending_removals:
self._commit_removals()
if self is other:
self.data.clear()
else:
self.data.difference_update(ref(item) for item in other)
return self
def intersection(self, other):
return self._apply(other, self.data.intersection)
__and__ = intersection
def intersection_update(self, other):
if self._pending_removals:
self._commit_removals()
self.data.intersection_update(ref(item) for item in other)
def __iand__(self, other):
if self._pending_removals:
self._commit_removals()
self.data.intersection_update(ref(item) for item in other)
return self
def issubset(self, other):
return self.data.issubset(ref(item) for item in other)
__lt__ = issubset
def __le__(self, other):
return self.data <= set(ref(item) for item in other)
def issuperset(self, other):
return self.data.issuperset(ref(item) for item in other)
__gt__ = issuperset
def __ge__(self, other):
return self.data >= set(ref(item) for item in other)
def __eq__(self, other):
if not isinstance(other, self.__class__):
return NotImplemented
return self.data == set(ref(item) for item in other)
def symmetric_difference(self, other):
return self._apply(other, self.data.symmetric_difference)
__xor__ = symmetric_difference
def symmetric_difference_update(self, other):
if self._pending_removals:
self._commit_removals()
if self is other:
self.data.clear()
else:
self.data.symmetric_difference_update(ref(item) for item in other)
def __ixor__(self, other):
if self._pending_removals:
self._commit_removals()
if self is other:
self.data.clear()
else:
self.data.symmetric_difference_update(ref(item) for item in other)
return self
def union(self, other):
return self._apply(other, self.data.union)
__or__ = union
def isdisjoint(self, other):
return len(self.intersection(other)) == 0

376
Lib/test/test_weakset.py Normal file
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@ -0,0 +1,376 @@
import unittest
from test import test_support
from weakref import proxy, ref, WeakSet
import operator
import copy
import string
import os
from random import randrange, shuffle
import sys
import warnings
import collections
import gc
import contextlib
class Foo:
pass
class SomeClass(object):
def __init__(self, value):
self.value = value
def __eq__(self, other):
if type(other) != type(self):
return False
return other.value == self.value
def __ne__(self, other):
return not self.__eq__(other)
def __hash__(self):
return hash((SomeClass, self.value))
class TestWeakSet(unittest.TestCase):
def setUp(self):
# need to keep references to them
self.items = [SomeClass(c) for c in ('a', 'b', 'c')]
self.items2 = [SomeClass(c) for c in ('x', 'y', 'z')]
self.letters = [SomeClass(c) for c in string.ascii_letters]
self.s = WeakSet(self.items)
self.d = dict.fromkeys(self.items)
self.obj = SomeClass('F')
self.fs = WeakSet([self.obj])
def test_methods(self):
weaksetmethods = dir(WeakSet)
for method in dir(set):
if method == 'test_c_api' or method.startswith('_'):
continue
self.assertIn(method, weaksetmethods,
"WeakSet missing method " + method)
def test_new_or_init(self):
self.assertRaises(TypeError, WeakSet, [], 2)
def test_len(self):
self.assertEqual(len(self.s), len(self.d))
self.assertEqual(len(self.fs), 1)
del self.obj
self.assertEqual(len(self.fs), 0)
def test_contains(self):
for c in self.letters:
self.assertEqual(c in self.s, c in self.d)
self.assertRaises(TypeError, self.s.__contains__, [[]])
self.assertIn(self.obj, self.fs)
del self.obj
self.assertNotIn(SomeClass('F'), self.fs)
def test_union(self):
u = self.s.union(self.items2)
for c in self.letters:
self.assertEqual(c in u, c in self.d or c in self.items2)
self.assertEqual(self.s, WeakSet(self.items))
self.assertEqual(type(u), WeakSet)
self.assertRaises(TypeError, self.s.union, [[]])
for C in set, frozenset, dict.fromkeys, list, tuple:
x = WeakSet(self.items + self.items2)
c = C(self.items2)
self.assertEqual(self.s.union(c), x)
def test_or(self):
i = self.s.union(self.items2)
self.assertEqual(self.s | set(self.items2), i)
self.assertEqual(self.s | frozenset(self.items2), i)
def test_intersection(self):
i = self.s.intersection(self.items2)
for c in self.letters:
self.assertEqual(c in i, c in self.d and c in self.items2)
self.assertEqual(self.s, WeakSet(self.items))
self.assertEqual(type(i), WeakSet)
for C in set, frozenset, dict.fromkeys, list, tuple:
x = WeakSet([])
self.assertEqual(self.s.intersection(C(self.items2)), x)
def test_isdisjoint(self):
self.assertTrue(self.s.isdisjoint(WeakSet(self.items2)))
self.assertTrue(not self.s.isdisjoint(WeakSet(self.letters)))
def test_and(self):
i = self.s.intersection(self.items2)
self.assertEqual(self.s & set(self.items2), i)
self.assertEqual(self.s & frozenset(self.items2), i)
def test_difference(self):
i = self.s.difference(self.items2)
for c in self.letters:
self.assertEqual(c in i, c in self.d and c not in self.items2)
self.assertEqual(self.s, WeakSet(self.items))
self.assertEqual(type(i), WeakSet)
self.assertRaises(TypeError, self.s.difference, [[]])
def test_sub(self):
i = self.s.difference(self.items2)
self.assertEqual(self.s - set(self.items2), i)
self.assertEqual(self.s - frozenset(self.items2), i)
def test_symmetric_difference(self):
i = self.s.symmetric_difference(self.items2)
for c in self.letters:
self.assertEqual(c in i, (c in self.d) ^ (c in self.items2))
self.assertEqual(self.s, WeakSet(self.items))
self.assertEqual(type(i), WeakSet)
self.assertRaises(TypeError, self.s.symmetric_difference, [[]])
def test_xor(self):
i = self.s.symmetric_difference(self.items2)
self.assertEqual(self.s ^ set(self.items2), i)
self.assertEqual(self.s ^ frozenset(self.items2), i)
def test_sub_and_super(self):
pl, ql, rl = map(lambda s: [SomeClass(c) for c in s], ['ab', 'abcde', 'def'])
p, q, r = map(WeakSet, (pl, ql, rl))
self.assertTrue(p < q)
self.assertTrue(p <= q)
self.assertTrue(q <= q)
self.assertTrue(q > p)
self.assertTrue(q >= p)
self.assertFalse(q < r)
self.assertFalse(q <= r)
self.assertFalse(q > r)
self.assertFalse(q >= r)
self.assertTrue(set('a').issubset('abc'))
self.assertTrue(set('abc').issuperset('a'))
self.assertFalse(set('a').issubset('cbs'))
self.assertFalse(set('cbs').issuperset('a'))
def test_gc(self):
# Create a nest of cycles to exercise overall ref count check
s = WeakSet(Foo() for i in range(1000))
for elem in s:
elem.cycle = s
elem.sub = elem
elem.set = WeakSet([elem])
def test_subclass_with_custom_hash(self):
# Bug #1257731
class H(WeakSet):
def __hash__(self):
return int(id(self) & 0x7fffffff)
s=H()
f=set()
f.add(s)
self.assertIn(s, f)
f.remove(s)
f.add(s)
f.discard(s)
def test_init(self):
s = WeakSet()
s.__init__(self.items)
self.assertEqual(s, self.s)
s.__init__(self.items2)
self.assertEqual(s, WeakSet(self.items2))
self.assertRaises(TypeError, s.__init__, s, 2);
self.assertRaises(TypeError, s.__init__, 1);
def test_constructor_identity(self):
s = WeakSet(self.items)
t = WeakSet(s)
self.assertNotEqual(id(s), id(t))
def test_hash(self):
self.assertRaises(TypeError, hash, self.s)
def test_clear(self):
self.s.clear()
self.assertEqual(self.s, WeakSet([]))
self.assertEqual(len(self.s), 0)
def test_copy(self):
dup = self.s.copy()
self.assertEqual(self.s, dup)
self.assertNotEqual(id(self.s), id(dup))
def test_add(self):
x = SomeClass('Q')
self.s.add(x)
self.assertIn(x, self.s)
dup = self.s.copy()
self.s.add(x)
self.assertEqual(self.s, dup)
self.assertRaises(TypeError, self.s.add, [])
self.fs.add(Foo())
self.assertTrue(len(self.fs) == 1)
self.fs.add(self.obj)
self.assertTrue(len(self.fs) == 1)
def test_remove(self):
x = SomeClass('a')
self.s.remove(x)
self.assertNotIn(x, self.s)
self.assertRaises(KeyError, self.s.remove, x)
self.assertRaises(TypeError, self.s.remove, [])
def test_discard(self):
a, q = SomeClass('a'), SomeClass('Q')
self.s.discard(a)
self.assertNotIn(a, self.s)
self.s.discard(q)
self.assertRaises(TypeError, self.s.discard, [])
def test_pop(self):
for i in range(len(self.s)):
elem = self.s.pop()
self.assertNotIn(elem, self.s)
self.assertRaises(KeyError, self.s.pop)
def test_update(self):
retval = self.s.update(self.items2)
self.assertEqual(retval, None)
for c in (self.items + self.items2):
self.assertIn(c, self.s)
self.assertRaises(TypeError, self.s.update, [[]])
def test_update_set(self):
self.s.update(set(self.items2))
for c in (self.items + self.items2):
self.assertIn(c, self.s)
def test_ior(self):
self.s |= set(self.items2)
for c in (self.items + self.items2):
self.assertIn(c, self.s)
def test_intersection_update(self):
retval = self.s.intersection_update(self.items2)
self.assertEqual(retval, None)
for c in (self.items + self.items2):
if c in self.items2 and c in self.items:
self.assertIn(c, self.s)
else:
self.assertNotIn(c, self.s)
self.assertRaises(TypeError, self.s.intersection_update, [[]])
def test_iand(self):
self.s &= set(self.items2)
for c in (self.items + self.items2):
if c in self.items2 and c in self.items:
self.assertIn(c, self.s)
else:
self.assertNotIn(c, self.s)
def test_difference_update(self):
retval = self.s.difference_update(self.items2)
self.assertEqual(retval, None)
for c in (self.items + self.items2):
if c in self.items and c not in self.items2:
self.assertIn(c, self.s)
else:
self.assertNotIn(c, self.s)
self.assertRaises(TypeError, self.s.difference_update, [[]])
self.assertRaises(TypeError, self.s.symmetric_difference_update, [[]])
def test_isub(self):
self.s -= set(self.items2)
for c in (self.items + self.items2):
if c in self.items and c not in self.items2:
self.assertIn(c, self.s)
else:
self.assertNotIn(c, self.s)
def test_symmetric_difference_update(self):
retval = self.s.symmetric_difference_update(self.items2)
self.assertEqual(retval, None)
for c in (self.items + self.items2):
if (c in self.items) ^ (c in self.items2):
self.assertIn(c, self.s)
else:
self.assertNotIn(c, self.s)
self.assertRaises(TypeError, self.s.symmetric_difference_update, [[]])
def test_ixor(self):
self.s ^= set(self.items2)
for c in (self.items + self.items2):
if (c in self.items) ^ (c in self.items2):
self.assertIn(c, self.s)
else:
self.assertNotIn(c, self.s)
def test_inplace_on_self(self):
t = self.s.copy()
t |= t
self.assertEqual(t, self.s)
t &= t
self.assertEqual(t, self.s)
t -= t
self.assertEqual(t, WeakSet())
t = self.s.copy()
t ^= t
self.assertEqual(t, WeakSet())
def test_eq(self):
# issue 5964
self.assertTrue(self.s == self.s)
self.assertTrue(self.s == WeakSet(self.items))
self.assertFalse(self.s == set(self.items))
self.assertFalse(self.s == list(self.items))
self.assertFalse(self.s == tuple(self.items))
self.assertFalse(self.s == 1)
def test_weak_destroy_while_iterating(self):
# Issue #7105: iterators shouldn't crash when a key is implicitly removed
# Create new items to be sure no-one else holds a reference
items = [SomeClass(c) for c in ('a', 'b', 'c')]
s = WeakSet(items)
it = iter(s)
next(it) # Trigger internal iteration
# Destroy an item
del items[-1]
gc.collect() # just in case
# We have removed either the first consumed items, or another one
self.assertIn(len(list(it)), [len(items), len(items) - 1])
del it
# The removal has been committed
self.assertEqual(len(s), len(items))
def test_weak_destroy_and_mutate_while_iterating(self):
# Issue #7105: iterators shouldn't crash when a key is implicitly removed
items = [SomeClass(c) for c in string.ascii_letters]
s = WeakSet(items)
@contextlib.contextmanager
def testcontext():
try:
it = iter(s)
next(it)
# Schedule an item for removal and recreate it
u = SomeClass(str(items.pop()))
gc.collect() # just in case
yield u
finally:
it = None # should commit all removals
with testcontext() as u:
self.assertNotIn(u, s)
with testcontext() as u:
self.assertRaises(KeyError, s.remove, u)
self.assertNotIn(u, s)
with testcontext() as u:
s.add(u)
self.assertIn(u, s)
t = s.copy()
with testcontext() as u:
s.update(t)
self.assertEqual(len(s), len(t))
with testcontext() as u:
s.clear()
self.assertEqual(len(s), 0)
def test_main(verbose=None):
test_support.run_unittest(TestWeakSet)
if __name__ == "__main__":
test_main(verbose=True)

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@ -24,6 +24,7 @@ class Test_TestResult(unittest.TestCase):
self.assertEqual(result.testsRun, 0) self.assertEqual(result.testsRun, 0)
self.assertEqual(result.shouldStop, False) self.assertEqual(result.shouldStop, False)
# "This method can be called to signal that the set of tests being # "This method can be called to signal that the set of tests being
# run should be aborted by setting the TestResult's shouldStop # run should be aborted by setting the TestResult's shouldStop
# attribute to True." # attribute to True."

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@ -20,6 +20,8 @@ from _weakref import (
ProxyType, ProxyType,
ReferenceType) ReferenceType)
from _weakrefset import WeakSet
from exceptions import ReferenceError from exceptions import ReferenceError
@ -27,7 +29,7 @@ ProxyTypes = (ProxyType, CallableProxyType)
__all__ = ["ref", "proxy", "getweakrefcount", "getweakrefs", __all__ = ["ref", "proxy", "getweakrefcount", "getweakrefs",
"WeakKeyDictionary", "ReferenceError", "ReferenceType", "ProxyType", "WeakKeyDictionary", "ReferenceError", "ReferenceType", "ProxyType",
"CallableProxyType", "ProxyTypes", "WeakValueDictionary"] "CallableProxyType", "ProxyTypes", "WeakValueDictionary", 'WeakSet']
class WeakValueDictionary(UserDict.UserDict): class WeakValueDictionary(UserDict.UserDict):

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@ -37,6 +37,8 @@ Library
True/False. This makes Fraction <=> complex comparisons consistent with True/False. This makes Fraction <=> complex comparisons consistent with
int <=> complex, float <=> complex, and complex <=> complex comparisons. int <=> complex, float <=> complex, and complex <=> complex comparisons.
- Addition of ``WeakSet`` to the ``weakref`` module.
- logging: Added LOG_FTP to SysLogHandler and updated documentation. - logging: Added LOG_FTP to SysLogHandler and updated documentation.
- Issue #8205: Remove the "Modules" directory from sys.path when Python is - Issue #8205: Remove the "Modules" directory from sys.path when Python is