[Rails][CodeReading] Rails::Initializer (7) add_plugin_load_paths

Initializer.process で7番目に呼ばれる add_plugin_load_paths メソッド。

    def add_plugin_load_paths
      plugin_loader.add_plugin_load_paths
    end

plugin_loader (実体はRails::Plugin::Loader) に委譲されているので、そちらをみてみます。

# rails-2.3.3/lib/rails/plugin/loader.rb
      def add_plugin_load_paths
        plugins.each do |plugin|
          plugin.load_paths.each do |path|
            $LOAD_PATH.insert(application_lib_index + 1, path)

            ActiveSupport::Dependencies.load_paths << path

            unless configuration.reload_plugins?
              ActiveSupport::Dependencies.load_once_paths << path
            end
          end
        end

        $LOAD_PATH.uniq!
      end

plugins というのは Rails::Plugin の配列で、Plugin.load_paths というのが $LOAD_PATH や ActiveSupport::Dependencies.load_paths に追加されています。その Plugin.load_paths の正体がこれ。

# rails-2.3.3/lib/rails/plugin.rb
module Rails
  class Plugin
    ～～　略　～～
    def initialize(directory)
      @directory = directory
      @name      = File.basename(@directory) rescue nil
      @loaded    = false
    end
    ～～　略　～～
    def load_paths
      report_nonexistant_or_empty_plugin! unless valid?
      
      returning [] do |load_paths|
        load_paths << lib_path  if has_lib_directory?
        load_paths << app_paths if has_app_directory?
      end.flatten
    end
    ～～　略　～～
    private
      def app_paths
        [ File.join(directory, 'app', 'models'), File.join(directory, 'app', 'helpers'), controller_path, metal_path ]
      end
      
      def lib_path
        File.join(directory, 'lib')
      end
  end
end

[Rails][CodeReading] Railsの初期化コードを読む (イントロ＆目次)