require "rails/plugin" module Rails class Plugin class Loader attr_reader :initializer # Creates a new Plugin::Loader instance, associated with the given # Rails::Initializer. This default implementation automatically locates # all plugins, and adds all plugin load paths, when it is created. The plugins # are then fully loaded (init.rb is evaluated) when load_plugins is called. # # It is the loader's responsibility to ensure that only the plugins specified # in the configuration are actually loaded, and that the order defined # is respected. def initialize(initializer) @initializer = initializer end # Returns the plugins to be loaded, in the order they should be loaded. def plugins @plugins ||= all_plugins.select { |plugin| should_load?(plugin) }.sort { |p1, p2| order_plugins(p1, p2) } end # Returns all the plugins that could be found by the current locators. def all_plugins @all_plugins ||= locate_plugins @all_plugins end def load_plugins plugins.each do |plugin| plugin.load(initializer) register_plugin_as_loaded(plugin) end ensure_all_registered_plugins_are_loaded! end # Adds the load paths for every plugin into the $LOAD_PATH. Plugin load paths are # added *after* the application's lib directory, to ensure that an application # can always override code within a plugin. # # Plugin load paths are also added to Dependencies.load_paths, and Dependencies.load_once_paths. def add_plugin_load_paths plugins.each do |plugin| plugin.load_paths.each do |path| $LOAD_PATH.insert(application_lib_index + 1, path) Dependencies.load_paths << path unless Rails.configuration.reload_plugins? Dependencies.load_once_paths << path end end end $LOAD_PATH.uniq! end protected # The locate_plugins method uses each class in config.plugin_locators to # find the set of all plugins available to this Rails application. def locate_plugins configuration.plugin_locators.map { |locator| locator.new(initializer).plugins }.flatten # TODO: sorting based on config.plugins end def register_plugin_as_loaded(plugin) initializer.loaded_plugins << plugin end def configuration initializer.configuration end def should_load?(plugin) # uses Plugin#name and Plugin#valid? enabled?(plugin) && plugin.valid? end def order_plugins(plugin_a, plugin_b) if !explicit_plugin_loading_order? plugin_a <=> plugin_b else if !explicitly_enabled?(plugin_a) && !explicitly_enabled?(plugin_b) plugin_a <=> plugin_b else effective_order_of(plugin_a) <=> effective_order_of(plugin_b) end end end def effective_order_of(plugin) if explicitly_enabled?(plugin) registered_plugin_names.index(plugin.name) else registered_plugin_names.index('all') end end def application_lib_index $LOAD_PATH.index(File.join(RAILS_ROOT, 'lib')) || 0 end def enabled?(plugin) !explicit_plugin_loading_order? || registered?(plugin) end def explicit_plugin_loading_order? !registered_plugin_names.nil? end def registered?(plugin) explicit_plugin_loading_order? && registered_plugins_names_plugin?(plugin) end def explicitly_enabled?(plugin) !explicit_plugin_loading_order? || explicitly_registered?(plugin) end def explicitly_registered?(plugin) explicit_plugin_loading_order? && registered_plugin_names.include?(plugin.name) end def registered_plugins_names_plugin?(plugin) registered_plugin_names.include?(plugin.name) || registered_plugin_names.include?('all') end # The plugins that have been explicitly listed with config.plugins. If this list is nil # then it means the client does not care which plugins or in what order they are loaded, # so we load all in alphabetical order. If it is an empty array, we load no plugins, if it is # non empty, we load the named plugins in the order specified. def registered_plugin_names configuration.plugins ? configuration.plugins.map(&:to_s) : nil end def loaded?(plugin_name) initializer.loaded_plugins.detect { |plugin| plugin.name == plugin_name.to_s } end def ensure_all_registered_plugins_are_loaded! if explicit_plugin_loading_order? if configuration.plugins.detect {|plugin| plugin != :all && !loaded?(plugin) } missing_plugins = configuration.plugins - (plugins + [:all]) raise LoadError, "Could not locate the following plugins: #{missing_plugins.to_sentence}" end end end end end end