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Contents
#--
# Semaphore
#
# Copyright (c) 2005 Fukumoto
#
# Ruby License
#
# This module is free software. You may use, modify, and/or redistribute this
# software under the same terms as Ruby.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.
#
# ==========================================================================
# Revision History
# ==========================================================================
#
# 2005-04-28 Trans - Ported to Calibre.
#
# ==========================================================================
#++
#:title: Semaphore
#
# Technically a semaphore is simply an integer variable which
# has an execution queue associated with it.
#
# == Usage
#
# s = Semaphore.new( 4 )
#
# TODO
#
# == Author(s)
#
# * Fukumoto
#
class Semaphore
def initialize(initvalue = 0)
@counter = initvalue
@waiting_list = []
end
def wait
Thread.critical = true
if (@counter -= 1) < 0
@waiting_list.push(Thread.current)
Thread.stop
end
self
ensure
Thread.critical = false
end
def signal
Thread.critical = true
begin
if (@counter += 1) <= 0
t = @waiting_list.shift
t.wakeup if t
end
rescue ThreadError
retry
end
self
ensure
Thread.critical = false
end
alias_method( :down, :wait )
alias_method( :up, :signal )
alias_method( :p, :wait )
alias_method( :v, :signal )
def exclusive
wait
yield
ensure
signal
end
alias_method( :synchronize, :exclusive )
end
# _____ _
# |_ _|__ ___| |_
# | |/ _ \/ __| __|
# | | __/\__ \ |_
# |_|\___||___/\__|
#
# TODO
=begin #test
require 'test/unit'
=end
Version data entries
7 entries across 7 versions & 1 rubygems