autoload threadsafe

autoload_threadsafe.rb

# Load this file before load anything.
# JRuby-Rack will load rack before load rails, so should load this file when JRuby runtime initialized.
# Call AutoloadThreadsafe.eager_load_all! at the end of rails environment rb

module AutoloadThreadsafe
  module Recorder
    def self.included(base)
      base.class_eval do
        alias :unsafe_autoload :autoload
        def autoload(m, filename)
          AutoloadThreadsafe.record(self, m)
          unsafe_autoload(m, filename)
        end
      end
    end
  end

  def record(parent, constant_name)
    autoload_constants << "#{parent.to_s == 'main' ? '' : parent}::#{constant_name}"
  end

  def autoload_constants
    @autoload_constants ||= []
  end

  def attach!
    [Kernel, Module].each do |m|
      unless m.ancestors.include?(Recorder)
        m.send(:include, Recorder)
      end
    end
  end

  def eager_load_all!
    autoload_constants.delete_if do |f|
      begin
        f.constantize
      rescue LoadError => e
        # ignore it, no one use it
      end
    end
  end

  extend self
end

AutoloadThreadsafe.attach!