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f449c04a36
empty. [ruby-dev:22207] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@5159 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
83 lines
1.9 KiB
Ruby
83 lines
1.9 KiB
Ruby
# Weak Reference class that does not bother GCing.
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#
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# Usage:
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# foo = Object.new
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# foo = Object.new
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# p foo.to_s # original's class
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# foo = WeakRef.new(foo)
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# p foo.to_s # should be same class
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# ObjectSpace.garbage_collect
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# p foo.to_s # should raise exception (recycled)
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require "delegate"
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class WeakRef<Delegator
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class RefError<StandardError
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end
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@@id_map = {} # obj -> [ref,...]
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@@id_rev_map = {} # ref -> obj
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@@final = lambda{|id|
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__old_status = Thread.critical
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Thread.critical = true
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begin
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rids = @@id_map[id]
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if rids
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for rid in rids
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@@id_rev_map.delete(rid)
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end
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@@id_map.delete(id)
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end
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rid = @@id_rev_map[id]
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if rid
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@@id_rev_map.delete(id)
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@@id_map[rid].delete(id)
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@@id_map.delete(rid) if @@id_map[rid].empty?
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end
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ensure
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Thread.critical = __old_status
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end
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}
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def initialize(orig)
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super
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@__id = orig.__id__
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ObjectSpace.define_finalizer orig, @@final
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ObjectSpace.define_finalizer self, @@final
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__old_status = Thread.critical
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begin
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Thread.critical = true
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@@id_map[@__id] = [] unless @@id_map[@__id]
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ensure
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Thread.critical = __old_status
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end
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@@id_map[@__id].push self.__id__
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@@id_rev_map[self.__id__] = @__id
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end
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def __getobj__
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unless @@id_rev_map[self.__id__] == @__id
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raise RefError, "Illegal Reference - probably recycled", caller(2)
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end
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begin
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ObjectSpace._id2ref(@__id)
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rescue RangeError
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raise RefError, "Illegal Reference - probably recycled", caller(2)
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end
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end
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def weakref_alive?
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@@id_rev_map[self.__id__] == @__id
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end
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end
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if __FILE__ == $0
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require 'thread'
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foo = Object.new
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p foo.to_s # original's class
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foo = WeakRef.new(foo)
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p foo.to_s # should be same class
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ObjectSpace.garbage_collect
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p foo.to_s # should raise exception (recycled)
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end
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