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# DestroyFlag adds a flag and a corresponding reader method to any active record
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# during deletion. The flag is set to true using before_destroy callback so during
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# complicated association deletions you can check whether the deletion includes
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# the object, e.g. we normally prevent deletion of primary interface in it's
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# before filter but we have to allow it when we delete associated host.
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#
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# class Host
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# include DestroyFlag
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# end
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#
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# class Nic
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# belongs_to :host
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# before_destroy :keep_primary, :if => Proc.new { |nic| nic.primary? }
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#
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# def keep_primary
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# unless host.being_destroyed? # Here we use being_destroyed? flag
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# raise 'we can not delete primary'
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# end
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# end
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# end
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#
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module DestroyFlag
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extend ActiveSupport::Concern
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def being_destroyed?
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@_active_record_being_destroyed
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end
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included do
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attr_accessor :_active_record_being_destroyed
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before_destroy { |record| record._active_record_being_destroyed = true }
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end
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end
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