76 lines
1.5 KiB
Ruby
76 lines
1.5 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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ObjectSpace.add_finalizer(lambda{|id|
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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[rid] = nil
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end
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ID_MAP[id] = nil
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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[id] = nil
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ID_MAP[rid].delete(id)
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ID_MAP[rid] = nil if ID_MAP[rid].empty?
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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.call_finalizer orig
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ObjectSpace.call_finalizer self
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ID_MAP[@__id] = [] unless ID_MAP[@__id]
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ID_MAP[@__id].concat 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_MAP[@__id]
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raise RefError, "Illegal Reference - probably recycled", caller(2)
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end
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ObjectSpace._id2ref(@__id)
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end
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def weakref_alive?
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if ID_MAP[@__id]
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true
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else
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false
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end
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end
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def []
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__getobj__
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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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