82 lines
2.0 KiB
Ruby
82 lines
2.0 KiB
Ruby
module V8
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module Weak
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# weak refs are broken on MRI 1.9 and merely slow on 1.8
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# so we mitigate this by using the 'ref' gem. However, this
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# only mitigates the problem. Under heavy load, you will still
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# get different or terminated objects being returned. bad stuff.
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#
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# If you are having problems with this, an upgrade to 2.0 is *highly*
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# recommended.
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#
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# for other platforms we just use the stdlib 'weakref'
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# implementation
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if defined?(RUBY_ENGINE) && RUBY_ENGINE == 'ruby' && RUBY_VERSION < '2.0.0'
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require 'ref'
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Ref = ::Ref::WeakReference
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WeakValueMap = ::Ref::WeakValueMap
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else
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require 'weakref'
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class Ref
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def initialize(object)
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@ref = ::WeakRef.new(object)
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end
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def object
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@ref.__getobj__
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rescue ::WeakRef::RefError
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nil
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end
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end
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class WeakValueMap
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def initialize
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@values = {}
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end
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def [](key)
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if ref = @values[key]
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ref.object
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end
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end
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def []=(key, value)
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ref = V8::Weak::Ref.new(value)
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ObjectSpace.define_finalizer(value, self.class.ensure_cleanup(@values, key, ref))
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@values[key] = ref
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end
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def self.ensure_cleanup(values,key,ref)
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proc {
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values.delete(key) if values[key] == ref
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}
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end
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end
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end
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module Cell
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def weakcell(name, &block)
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unless storage = instance_variable_get("@#{name}")
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storage = instance_variable_set("@#{name}", Storage.new)
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end
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storage.access(&block)
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end
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class Storage
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def access(&block)
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if @ref
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@ref.object || populate(block)
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else
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populate(block)
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end
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end
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private
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def populate(block)
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occupant = block.call()
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@ref = V8::Weak::Ref.new(occupant)
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return occupant
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end
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end
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end
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end
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end |