Module: ActiveSupport::Memoizable

Included in:
ActionDispatch::Http::Headers, ActionView::Helpers::DateTimeSelector
Defined in:
activesupport/lib/active_support/memoizable.rb

Defined Under Namespace

Modules: InstanceMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.memoized_ivar_for(symbol) ⇒ Object



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# File 'activesupport/lib/active_support/memoizable.rb', line 6

def self.memoized_ivar_for(symbol)
  "@_memoized_#{symbol.to_s.sub(/\?\Z/, '_query').sub(/!\Z/, '_bang')}".to_sym
end

Instance Method Details

#memoize(*symbols) ⇒ Object



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# File 'activesupport/lib/active_support/memoizable.rb', line 59

def memoize(*symbols)
  symbols.each do |symbol|
    original_method = :_unmemoized_#{symbol}"
    memoized_ivar = ActiveSupport::Memoizable.memoized_ivar_for(symbol)

    class_eval <<-EOS, __FILE__, __LINE__ + 1
      include InstanceMethods                                                  # include InstanceMethods
                                                                               #
      if method_defined?(:#{original_method})                                  # if method_defined?(:_unmemoized_mime_type)
        raise "Already memoized #{symbol}"                                     #   raise "Already memoized mime_type"
      end                                                                      # end
      alias #{original_method} #{symbol}                                       # alias _unmemoized_mime_type mime_type
                                                                               #
      if instance_method(:#{symbol}).arity == 0                                # if instance_method(:mime_type).arity == 0
        def #{symbol}(reload = false)                                          #   def mime_type(reload = false)
          if reload || !defined?(#{memoized_ivar}) || #{memoized_ivar}.empty?  #     if reload || !defined?(@_memoized_mime_type) || @_memoized_mime_type.empty?
            #{memoized_ivar} = [#{original_method}]                            #       @_memoized_mime_type = [_unmemoized_mime_type]
          end                                                                  #     end
          #{memoized_ivar}[0]                                                  #     @_memoized_mime_type[0]
        end                                                                    #   end
      else                                                                     # else
        def #{symbol}(*args)                                                   #   def mime_type(*args)
          #{memoized_ivar} ||= {} unless frozen?                               #     @_memoized_mime_type ||= {} unless frozen?
          reload = args.pop if args.last == true || args.last == :reload       #     reload = args.pop if args.last == true || args.last == :reload
                                                                               #
          if defined?(#{memoized_ivar}) && #{memoized_ivar}                    #     if defined?(@_memoized_mime_type) && @_memoized_mime_type
            if !reload && #{memoized_ivar}.has_key?(args)                      #       if !reload && @_memoized_mime_type.has_key?(args)
              #{memoized_ivar}[args]                                           #         @_memoized_mime_type[args]
            elsif #{memoized_ivar}                                             #       elsif @_memoized_mime_type
              #{memoized_ivar}[args] = #{original_method}(*args)               #         @_memoized_mime_type[args] = _unmemoized_mime_type(*args)
            end                                                                #       end
          else                                                                 #     else
            #{original_method}(*args)                                          #       _unmemoized_mime_type(*args)
          end                                                                  #     end
        end                                                                    #   end
      end                                                                      # end
                                                                               #
      if private_method_defined?(#{original_method.inspect})                   # if private_method_defined?(:_unmemoized_mime_type)
        private #{symbol.inspect}                                              #   private :mime_type
      end                                                                      # end
    EOS
  end
end