diff options
Diffstat (limited to 'activesupport')
4 files changed, 148 insertions, 0 deletions
diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG index 80f6c76401..4b22b6e7b2 100644 --- a/activesupport/CHANGELOG +++ b/activesupport/CHANGELOG @@ -1,5 +1,7 @@ *SVN* +* Add new superclass_delegating_accessors. Similar to class inheritable attributes but with subtly different semantics. [Koz, tarmo] + * Change JSON to encode %w(< > &) as 4 digit hex codes to be in compliance with the JSON spec. Closes #9975 [josh, chuyeow, tpope] * Fix JSON encoding/decoding bugs dealing with /'s. Closes #9990 [Rick, theamazingrando] diff --git a/activesupport/lib/active_support/core_ext/class.rb b/activesupport/lib/active_support/core_ext/class.rb index 83eb8135f4..44ad6c8c08 100644 --- a/activesupport/lib/active_support/core_ext/class.rb +++ b/activesupport/lib/active_support/core_ext/class.rb @@ -1,3 +1,4 @@ require 'active_support/core_ext/class/attribute_accessors' require 'active_support/core_ext/class/inheritable_attributes' require 'active_support/core_ext/class/removal' +require 'active_support/core_ext/class/delegating_attributes' diff --git a/activesupport/lib/active_support/core_ext/class/delegating_attributes.rb b/activesupport/lib/active_support/core_ext/class/delegating_attributes.rb new file mode 100644 index 0000000000..f5f0ef8779 --- /dev/null +++ b/activesupport/lib/active_support/core_ext/class/delegating_attributes.rb @@ -0,0 +1,40 @@ +# These class attributes behave something like the class +# inheritable accessors. But instead of copying the hash over at +# the time the subclass is first defined, the accessors simply +# delegate to their superclass unless they have been given a +# specific value. This stops the strange situation where values +# set after class definition don't get applied to subclasses. +class Class + def superclass_delegating_reader(*names) + class_name_to_stop_searching_on = self.superclass.name.blank? ? "Object" : self.superclass.name + names.each do |name| + class_eval <<-EOS + def self.#{name} + if defined?(@#{name}) + @#{name} + elsif superclass < #{class_name_to_stop_searching_on} && superclass.respond_to?(:#{name}) + superclass.#{name} + end + end + def #{name} + self.class.#{name} + end + EOS + end + end + + def superclass_delegating_writer(*names) + names.each do |name| + class_eval <<-EOS + def self.#{name}=(value) + @#{name} = value + end + EOS + end + end + + def superclass_delegating_accessor(*names) + superclass_delegating_reader(*names) + superclass_delegating_writer(*names) + end +end
\ No newline at end of file diff --git a/activesupport/test/core_ext/class/delegating_attributes_test.rb b/activesupport/test/core_ext/class/delegating_attributes_test.rb new file mode 100644 index 0000000000..59c0a6f63c --- /dev/null +++ b/activesupport/test/core_ext/class/delegating_attributes_test.rb @@ -0,0 +1,105 @@ +require File.dirname(__FILE__) + '/../../abstract_unit' + +module DelegatingFixtures + class Parent + end + + class Child < Parent + superclass_delegating_accessor :some_attribute + end + + class Mokopuna < Child + end +end + +class DelegatingAttributesTest < Test::Unit::TestCase + include DelegatingFixtures + attr_reader :single_class + + def setup + @single_class = Class.new(Object) + end + + def test_simple_reader_declaration + single_class.superclass_delegating_reader :only_reader + # The class and instance should have an accessor, but there + # should be no mutator + assert single_class.respond_to?(:only_reader) + assert single_class.public_instance_methods.include?("only_reader") + assert !single_class.respond_to?(:only_reader=) + end + + def test_simple_writer_declaration + single_class.superclass_delegating_writer :only_writer + # The class should have a mutator, the instances shouldn't + # neither should have an accessor + assert single_class.respond_to?(:only_writer=) + assert !single_class.public_instance_methods.include?("only_writer=") + assert !single_class.public_instance_methods.include?("only_writer") + assert !single_class.respond_to?(:only_writer) + end + + def test_simple_accessor_declaration + single_class.superclass_delegating_accessor :both + # Class should have accessor and mutator + # the instance should have an accessor only + assert single_class.respond_to?(:both) + assert single_class.respond_to?(:both=) + assert single_class.public_instance_methods.include?("both") + assert !single_class.public_instance_methods.include?("both=") + end + + def test_working_with_simple_attributes + single_class.superclass_delegating_accessor :both + single_class.both= "HMMM" + assert_equal "HMMM", single_class.both + assert_equal "HMMM", single_class.new.both + end + + def test_working_with_accessors + single_class.superclass_delegating_reader :only_reader + single_class.instance_variable_set("@only_reader", "reading only") + assert_equal "reading only", single_class.only_reader + assert_equal "reading only", single_class.new.only_reader + end + + def test_working_with_simple_mutators + single_class.superclass_delegating_writer :only_writer + single_class.only_writer="written" + assert_equal "written", single_class.instance_variable_get("@only_writer") + end + + def test_child_class_delegates_to_parent_but_can_be_overridden + parent = Class.new + parent.superclass_delegating_accessor :both + child = Class.new(parent) + parent.both= "1" + assert_equal "1", child.both + + child.both="2" + assert_equal "1", parent.both + assert_equal "2", child.both + + parent.both="3" + assert_equal "3", parent.both + assert_equal "2", child.both + end + + def test_delegation_stops_at_the_right_level + assert_nil Mokopuna.some_attribute + assert_nil Child.some_attribute + Child.some_attribute="1" + assert_equal "1", Mokopuna.some_attribute + ensure + Child.some_attribute=nil + end + + def test_delegation_stops_for_nil + Mokopuna.some_attribute = nil + Child.some_attribute="1" + + assert_equal "1", Child.some_attribute + assert_nil Mokopuna.some_attribute + end + +end
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