# File lib/nanoc/extra/checking/checks/external_links.rb, line 63 def select_invalid(hrefs) enum = ArrayEnumerator.new(hrefs.sort) mutex = Mutex.new invalid = Set.new threads = [] 10.times do threads << Thread.new do loop do href = enum.next break if href.nil? res = self.validate(href) if res mutex.synchronize do invalid << res end end end end end threads.each { |t| t.join } invalid end