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author | David Heinemeier Hansson <david@loudthinking.com> | 2005-02-15 15:57:44 +0000 |
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committer | David Heinemeier Hansson <david@loudthinking.com> | 2005-02-15 15:57:44 +0000 |
commit | dc3d6eb9b4aaed051dd6d5a5a07f6c66b72da4c4 (patch) | |
tree | 1d77afa3e7a5af3d3d89c2121b5cecf6423d666d /activesupport/lib/active_support/class_inheritable_attributes.rb | |
parent | 45caae41c3fbfc7ba77c5e2dc70734fa80501828 (diff) | |
download | rails-dc3d6eb9b4aaed051dd6d5a5a07f6c66b72da4c4.tar.gz rails-dc3d6eb9b4aaed051dd6d5a5a07f6c66b72da4c4.tar.bz2 rails-dc3d6eb9b4aaed051dd6d5a5a07f6c66b72da4c4.zip |
Moved Active Support into its own gem
git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@624 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
Diffstat (limited to 'activesupport/lib/active_support/class_inheritable_attributes.rb')
-rw-r--r-- | activesupport/lib/active_support/class_inheritable_attributes.rb | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/class_inheritable_attributes.rb b/activesupport/lib/active_support/class_inheritable_attributes.rb new file mode 100644 index 0000000000..f9ca7af7b2 --- /dev/null +++ b/activesupport/lib/active_support/class_inheritable_attributes.rb @@ -0,0 +1,117 @@ +# Retain for backward compatibility. Methods are now included in Class. +module ClassInheritableAttributes # :nodoc: +end + +# Allows attributes to be shared within an inheritance hierarchy, but where each descendant gets a copy of +# their parents' attributes, instead of just a pointer to the same. This means that the child can add elements +# to, for example, an array without those additions being shared with either their parent, siblings, or +# children, which is unlike the regular class-level attributes that are shared across the entire hierarchy. +class Class # :nodoc: + def class_inheritable_reader(*syms) + syms.each do |sym| + class_eval <<-EOS + def self.#{sym} + read_inheritable_attribute(:#{sym}) + end + + def #{sym} + self.class.#{sym} + end + EOS + end + end + + def class_inheritable_writer(*syms) + syms.each do |sym| + class_eval <<-EOS + def self.#{sym}=(obj) + write_inheritable_attribute(:#{sym}, obj) + end + + def #{sym}=(obj) + self.class.#{sym} = obj + end + EOS + end + end + + def class_inheritable_array_writer(*syms) + syms.each do |sym| + class_eval <<-EOS + def self.#{sym}=(obj) + write_inheritable_array(:#{sym}, obj) + end + + def #{sym}=(obj) + self.class.#{sym} = obj + end + EOS + end + end + + def class_inheritable_hash_writer(*syms) + syms.each do |sym| + class_eval <<-EOS + def self.#{sym}=(obj) + write_inheritable_hash(:#{sym}, obj) + end + + def #{sym}=(obj) + self.class.#{sym} = obj + end + EOS + end + end + + def class_inheritable_accessor(*syms) + class_inheritable_reader(*syms) + class_inheritable_writer(*syms) + end + + def class_inheritable_array(*syms) + class_inheritable_reader(*syms) + class_inheritable_array_writer(*syms) + end + + def class_inheritable_hash(*syms) + class_inheritable_reader(*syms) + class_inheritable_hash_writer(*syms) + end + + def inheritable_attributes + @inheritable_attributes ||= {} + end + + def write_inheritable_attribute(key, value) + inheritable_attributes[key] = value + end + + def write_inheritable_array(key, elements) + write_inheritable_attribute(key, []) if read_inheritable_attribute(key).nil? + write_inheritable_attribute(key, read_inheritable_attribute(key) + elements) + end + + def write_inheritable_hash(key, hash) + write_inheritable_attribute(key, {}) if read_inheritable_attribute(key).nil? + write_inheritable_attribute(key, read_inheritable_attribute(key).merge(hash)) + end + + def read_inheritable_attribute(key) + inheritable_attributes[key] + end + + def reset_inheritable_attributes + inheritable_attributes.clear + end + + private + def inherited_with_inheritable_attributes(child) + inherited_without_inheritable_attributes(child) if respond_to?(:inherited_without_inheritable_attributes) + child.instance_variable_set('@inheritable_attributes', inheritable_attributes.dup) + end + + if respond_to?(:inherited) + alias_method :inherited_without_inheritable_attributes, :inherited + end + alias_method :inherited, :inherited_with_inheritable_attributes +end |