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# Poor Man's Fiber (API compatible Thread based Fiber implementation for Ruby 1.8)
# (c) 2008 Aman Gupta (tmm1)
unless defined? Fiber
require 'thread'
class FiberError < StandardError; end
class Fiber
def initialize
raise ArgumentError, 'new Fiber requires a block' unless block_given?
@yield = Queue.new
@resume = Queue.new
@thread = Thread.new{ @yield.push [ *yield(*@resume.pop) ] }
@thread.abort_on_exception = true
@thread[:fiber] = self
end
attr_reader :thread
def alive?
@thread.alive?
end
def resume *args
raise FiberError, 'dead fiber called' unless @thread.alive?
raise FiberError, 'double resume' if @thread == Thread.current
@resume.push(args)
result = @yield.pop
result.size > 1 ? result : result.first
end
def resume!
@resume.push []
end
def yield *args
@yield.push(args)
result = @resume.pop
result.size > 1 ? result : result.first
end
def self.yield *args
raise FiberError, "can't yield from root fiber" unless fiber = Thread.current[:fiber]
fiber.yield(*args)
end
def self.current
Thread.current[:fiber] or raise FiberError, 'not inside a fiber'
end
def inspect
"#<#{self.class}:0x#{self.object_id.to_s(16)}>"
end
end
else
require 'fiber' unless Fiber.respond_to?(:current)
end
if __FILE__ == $0
f = Fiber.new{ puts 'hi'; p Fiber.yield(1); puts 'bye'; :done }
p f.resume
p f.resume(2)
end
__END__
$ ruby fbr.rb
hi
1
2
bye
:done
$ ruby1.9 fbr.rb
hi
1
2
bye
:done
|
