class SimplePool

# File lib/simple-pool.rb, line 4
def initialize(thread_num)
    @kill = false
    @stop = false
    @q = Queue.new
    @m = Mutex.new
    @cv = ConditionVariable.new
    @threads = []
    thread_num.times do |i|
        @threads << Thread.new{round_n_round}
    end
end

# File lib/simple-pool.rb, line 16
def invoke(&callback)
    @q << callback
    @m.synchronize{ @cv.broadcast }
end

# File lib/simple-pool.rb, line 21
def kill_right_now
    @kill = true
    @m.synchronize{ @cv.broadcast }
    @threads.each{|t| t.join}
end

# File lib/simple-pool.rb, line 27
def wait_until_finish
    @stop = true
    @m.synchronize{ @cv.broadcast }
    @threads.each{|t| t.join}
end

# File lib/simple-pool.rb, line 34
def do_it
    begin
        callback = @q.pop
        callback.call
    rescue

    end
end

# File lib/simple-pool.rb, line 43
def round_n_round
    until @kill do
        unless @q.empty?
            do_it
            next
        end

        if @stop
            @kill = true
            next
        end

        @m.synchronize{ @cv.wait(@m, 1) }
    end
end