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Diffstat (limited to 'activemodel/lib/active_model/configuration.rb')
-rw-r--r-- | activemodel/lib/active_model/configuration.rb | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/activemodel/lib/active_model/configuration.rb b/activemodel/lib/active_model/configuration.rb new file mode 100644 index 0000000000..1757c12ebf --- /dev/null +++ b/activemodel/lib/active_model/configuration.rb @@ -0,0 +1,134 @@ +require 'active_support/concern' +require 'active_support/core_ext/class/attribute' +require 'active_support/core_ext/class/attribute_accessors' + +module ActiveModel + # This API is for Rails' internal use and is not currently considered 'public', so + # it may change in the future without warning. + # + # It creates configuration attributes that can be inherited from a module down + # to a class that includes the module. E.g. + # + # module MyModel + # extend ActiveModel::Configuration + # config_attribute :awesome + # self.awesome = true + # end + # + # class Post + # include MyModel + # end + # + # Post.awesome # => true + # + # Post.awesome = false + # Post.awesome # => false + # MyModel.awesome # => true + # + # We assume that the module will have a ClassMethods submodule containing methods + # to be transferred to the including class' singleton class. + # + # Config options can also be defined directly on a class: + # + # class Post + # extend ActiveModel::Configuration + # config_attribute :awesome + # end + # + # So this allows us to define a module that doesn't care about whether it is being + # included in a class or a module: + # + # module Awesomeness + # extend ActiveSupport::Concern + # + # included do + # extend ActiveModel::Configuration + # config_attribute :awesome + # self.awesome = true + # end + # end + # + # class Post + # include Awesomeness + # end + # + # module AwesomeModel + # include Awesomeness + # end + module Configuration #:nodoc: + def config_attribute(name, options = {}) + klass = self.is_a?(Class) ? ClassAttribute : ModuleAttribute + klass.new(self, name, options).define + end + + class Attribute + attr_reader :host, :name, :options + + def initialize(host, name, options) + @host, @name, @options = host, name, options + end + + def instance_writer? + options.fetch(:instance_writer, false) + end + end + + class ClassAttribute < Attribute + def define + if options[:global] + host.cattr_accessor name, :instance_writer => instance_writer? + else + host.class_attribute name, :instance_writer => instance_writer? + end + end + end + + class ModuleAttribute < Attribute + def class_methods + @class_methods ||= begin + if host.const_defined?(:ClassMethods, false) + host.const_get(:ClassMethods) + else + host.const_set(:ClassMethods, Module.new) + end + end + end + + def define + host.singleton_class.class_eval <<-CODE, __FILE__, __LINE__ + attr_accessor :#{name} + def #{name}?; !!#{name}; end + CODE + + name, host = self.name, self.host + + class_methods.class_eval do + define_method(name) { host.send(name) } + define_method("#{name}?") { !!send(name) } + end + + host.class_eval <<-CODE + def #{name}; defined?(@#{name}) ? @#{name} : self.class.#{name}; end + def #{name}?; !!#{name}; end + CODE + + if options[:global] + class_methods.class_eval do + define_method("#{name}=") { |val| host.send("#{name}=", val) } + end + else + class_methods.class_eval <<-CODE, __FILE__, __LINE__ + def #{name}=(val) + singleton_class.class_eval do + remove_possible_method(:#{name}) + define_method(:#{name}) { val } + end + end + CODE + end + + host.send(:attr_writer, name) if instance_writer? + end + end + end +end |