diff options
Diffstat (limited to 'activerecord/lib/active_record/attribute_decorators.rb')
-rw-r--r-- | activerecord/lib/active_record/attribute_decorators.rb | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/attribute_decorators.rb b/activerecord/lib/active_record/attribute_decorators.rb new file mode 100644 index 0000000000..5b96623b6e --- /dev/null +++ b/activerecord/lib/active_record/attribute_decorators.rb @@ -0,0 +1,66 @@ +module ActiveRecord + module AttributeDecorators # :nodoc: + extend ActiveSupport::Concern + + included do + class_attribute :attribute_type_decorations, instance_accessor: false # :internal: + self.attribute_type_decorations = TypeDecorator.new + end + + module ClassMethods # :nodoc: + def decorate_attribute_type(column_name, decorator_name, &block) + matcher = ->(name, _) { name == column_name.to_s } + key = "_#{column_name}_#{decorator_name}" + decorate_matching_attribute_types(matcher, key, &block) + end + + def decorate_matching_attribute_types(matcher, decorator_name, &block) + clear_caches_calculated_from_columns + decorator_name = decorator_name.to_s + + # Create new hashes so we don't modify parent classes + self.attribute_type_decorations = attribute_type_decorations.merge(decorator_name => [matcher, block]) + end + + private + + def add_user_provided_columns(*) + super.map do |column| + decorated_type = attribute_type_decorations.apply(column.name, column.cast_type) + column.with_type(decorated_type) + end + end + end + + class TypeDecorator # :nodoc: + delegate :clear, to: :@decorations + + def initialize(decorations = {}) + @decorations = decorations + end + + def merge(*args) + TypeDecorator.new(@decorations.merge(*args)) + end + + def apply(name, type) + decorations = decorators_for(name, type) + decorations.inject(type) do |new_type, block| + block.call(new_type) + end + end + + private + + def decorators_for(name, type) + matching(name, type).map(&:last) + end + + def matching(name, type) + @decorations.values.select do |(matcher, _)| + matcher.call(name, type) + end + end + end + end +end |