blob: c31e959e742f958fb0421605a4f95b3fd5d41f7b (
plain)
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
|
# Weak Reference class that does not bother GCing.
#
# Usage:
# foo = Object.new
# foo.hash
# foo = WeakRef.new(foo)
# foo.hash
# ObjectSpace.garbage_collect
# foo.hash # => Raises WeakRef::RefError (because original GC'ed)
require "delegate"
class WeakRef<Delegator
class RefError<StandardError
end
ID_MAP = {}
ID_REV_MAP = {}
ObjectSpace.add_finalizer(lambda{|id|
rid = ID_MAP[id]
if rid
ID_REV_MAP[rid] = nil
ID_MAP[id] = nil
end
rid = ID_REV_MAP[id]
if rid
ID_REV_MAP[id] = nil
ID_MAP[rid] = nil
end
})
def initialize(orig)
super
@__id = orig.__id__
ObjectSpace.call_finalizer orig
ObjectSpace.call_finalizer self
ID_MAP[@__id] = self.__id__
ID_REV_MAP[self.id] = @__id
end
def __getobj__
unless ID_MAP[@__id]
raise RefError, "Illegal Reference - probably recycled", caller(2)
end
ObjectSpace._id2ref(@__id)
end
def weakref_alive?
if ID_MAP[@__id]
true
else
false
end
end
def []
__getobj__
end
end
if __FILE__ == $0
foo = Object.new
p foo.hash # original's hash value
foo = WeakRef.new(foo)
p foo.hash # should be same hash value
ObjectSpace.garbage_collect
p foo.hash # should raise exception (recycled)
end
|
