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Contents
# frozen_string_literal: true
module Polyphony
# Implements a limited resource pool
class ResourcePool
attr_reader :limit, :size
# Initializes a new resource pool
# @param opts [Hash] options
# @param &block [Proc] allocator block
def initialize(opts, &block)
@allocator = block
@limit = opts[:limit] || 4
@size = 0
@stock = Polyphony::Queue.new
@acquired_resources = {}
end
def available
@stock.size
end
def acquire(&block)
fiber = Fiber.current
return yield @acquired_resources[fiber] if @acquired_resources[fiber]
acquire_from_stock(fiber, &block)
end
def acquire_from_stock(fiber)
add_to_stock if (@stock.empty? || @stock.pending?) && @size < @limit
resource = @stock.shift
@acquired_resources[fiber] = resource
yield resource
ensure
if resource && @acquired_resources[fiber] == resource
@acquired_resources.delete(fiber)
@stock.push resource
end
end
def method_missing(sym, *args, &block)
acquire { |r| r.send(sym, *args, &block) }
end
def respond_to_missing?(*_args)
true
end
# Allocates a resource
# @return [any] allocated resource
def add_to_stock
@size += 1
resource = @allocator.call
@stock << resource
end
# Discards the currently-acquired resource
# instead of returning it to the pool when done.
def discard!
@size -= 1 if @acquired_resources.delete(Fiber.current)
end
def preheat!
add_to_stock while @size < @limit
end
end
end
Version data entries
51 entries across 51 versions & 1 rubygems