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Diffstat (limited to 'app/models/concerns/enum_inheritance.rb')
-rw-r--r-- | app/models/concerns/enum_inheritance.rb | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/app/models/concerns/enum_inheritance.rb b/app/models/concerns/enum_inheritance.rb new file mode 100644 index 00000000000..1df1f3d43fd --- /dev/null +++ b/app/models/concerns/enum_inheritance.rb @@ -0,0 +1,58 @@ +# frozen_string_literal: true + +module EnumInheritance + # == STI through Enum + # + # WARNING: Usage of STI is heavily discouraged: https://docs.gitlab.com/ee/development/database/single_table_inheritance.html + # + # Active Record allows definition of STI through the <tt>Base.inheritance_column</tt>. However, this stores the class + # name as string into the record, which is heavy and unnecessary. EnumInheritance adapts ActiveRecord to use an enum + # instead. + # + # Details: + # - Correct class mapping is specified in the <tt>self.sti_type_map<\tt>, which maps the symbol of the type to + # a fully classified class as string. + # - If the type passed does not have an specified class, then the class will be the base class + # + # Example + # class Animal + # include EnumInheritable + # + # enum animal_type: { + # dog: 1, + # cat: 2, + # bird: 3 + # } + # + # def self.inheritance_column_to_class_map = { + # dog: 'Animals::Dog', + # cat: 'Animals::Cat' + # } + # + # def self.inheritance_column = 'animal_type' + # end + # + # class Animals::Dog < Animal; end + # class Animals::Cat < Animal; end + extend ActiveSupport::Concern + + included do + def self.sti_class_to_enum_map = inheritance_column_to_class_map.invert + end + + class_methods do + extend ::Gitlab::Utils::Override + + def inheritance_column_to_class_map = {}.freeze + + override :sti_class_for + def sti_class_for(type_name) + inheritance_column_to_class_map[type_name.to_sym]&.constantize || base_class + end + + override :sti_name + def sti_name + sti_class_to_enum_map[name].to_s + end + end +end |