lib/drb/timeridconv.rb

   1 require 'drb/drb'
   2 require 'monitor'
   3
   4 module DRb
   5   class TimerIdConv < DRbIdConv
   6     class TimerHolder2
   7       include MonitorMixin
   8
   9       class InvalidIndexError < RuntimeError; end
  10
  11       def initialize(timeout=600)
  12         super()
  13         @sentinel = Object.new
  14         @gc = {}
  15         @curr = {}
  16         @renew = {}
  17         @timeout = timeout
  18         @keeper = keeper
  19       end
  20
  21       def add(obj)
  22         synchronize do
  23           key = obj.__id__
  24           @curr[key] = obj
  25           return key
  26         end
  27       end
  28
  29       def fetch(key, dv=@sentinel)
  30         synchronize do
  31           obj = peek(key)
  32           if obj == @sentinel
  33             return dv unless dv == @sentinel
  34             raise InvalidIndexError
  35           end
  36           @renew[key] = obj # KeepIt
  37           return obj
  38         end
  39       end
  40
  41       def include?(key)
  42         synchronize do
  43           obj = peek(key)
  44           return false if obj == @sentinel
  45           true
  46         end
  47       end
  48
  49       def peek(key)
  50         synchronize do
  51           return @curr.fetch(key, @renew.fetch(key, @gc.fetch(key, @sentinel)))
  52         end
  53       end
  54
  55       private
  56       def alternate
  57         synchronize do
  58           @gc = @curr       # GCed
  59           @curr = @renew
  60           @renew = {}
  61         end
  62       end
  63
  64       def keeper
  65         Thread.new do
  66           loop do
  67             size = alternate
  68             sleep(@timeout)
  69           end
  70         end
  71       end
  72     end
  73
  74     def initialize(timeout=600)
  75       @holder = TimerHolder2.new(timeout)
  76     end
  77
  78     def to_obj(ref)
  79       return super if ref.nil?
  80       @holder.fetch(ref)
  81     rescue TimerHolder2::InvalidIndexError
  82       raise "invalid reference"
  83     end
  84
  85     def to_id(obj)
  86       return @holder.add(obj)
  87     end
  88   end
  89 end
  90
  91 # DRb.install_id_conv(TimerIdConv.new)