1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
# -*- coding: utf-8 -*-
# Copyright 2018 gevent contributors. See LICENSE for details.
# cython: auto_pickle=False,embedsignature=True,always_allow_keywords=False
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from weakref import WeakKeyDictionary
from weakref import ref
from heapq import heappop
from heapq import heappush
__all__ = [
'IdentRegistry',
]
class ValuedWeakRef(ref):
"""
A weak ref with an associated value.
"""
# This seems entirely spurious; even on Python 2.7
# weakref.ref descends from object
# pylint: disable=slots-on-old-class
__slots__ = ('value',)
class IdentRegistry(object):
"""
Maintains a unique mapping of (small) positive integer identifiers
to objects that can be weakly referenced.
It is guaranteed that no two objects will have the the same
identifier at the same time, as long as those objects are
also uniquely hashable.
"""
def __init__(self):
# {obj -> (ident, wref(obj))}
self._registry = WeakKeyDictionary()
# A heap of numbers that have been used and returned
self._available_idents = []
def get_ident(self, obj):
"""
Retrieve the identifier for *obj*, creating one
if necessary.
"""
try:
return self._registry[obj][0]
except KeyError:
pass
if self._available_idents:
# Take the smallest free number
ident = heappop(self._available_idents)
else:
# Allocate a bigger one
ident = len(self._registry)
vref = ValuedWeakRef(obj, self._return_ident)
vref.value = ident # pylint:disable=assigning-non-slot,attribute-defined-outside-init
self._registry[obj] = (ident, vref)
return ident
def _return_ident(self, vref):
# By the time this is called, self._registry has been
# updated
if heappush is not None:
# Under some circumstances we can get called
# when the interpreter is shutting down, and globals
# aren't available any more.
heappush(self._available_idents, vref.value)
def __len__(self):
return len(self._registry)
from gevent._util import import_c_accel
import_c_accel(globals(), 'gevent.__ident')
|
