Contents

class Updates
  include Enumerable

  def initialize(base)
    @base, @updates, @orig = base, {}, {}
  end

  def add(attribute, new_value)
    @updates[attribute.to_s] = new_value
  end

  def keys
    @updates.keys
  end

  def each
    @updates.each { |attr| yield attr }
  end

  def each_pair
    @updates.each_pair { |attr,value| yield attr, value }
  end

  def clear(*attr_names)
    if attr_names.empty?
      @updates = {}
    else
      attr_names.each { |attr|  @updates.delete(attr.to_s) }
    end
  end

  def for?(attr)
    @updates.has_key?(attr.to_s)
  end

  def for(attr)
    @updates[attr.to_s]
  end
  alias :[] :for
end

module ClassMethods
  # Important! Tracking should be declared *after* associations
  def tracks(*fields)
    class_eval do
      def updates
        @updates ||= Updates.new(self)
      end
    end

    fields.each do |field|
      unless self.method_defined? field
        access = "read_attribute('#{field}')"
        if cache_attribute?(field.to_s)
          access = "@attributes_cache['#{field}'] ||= #{access}"
        end
        class_eval "def #{field}; r=(#{access};) end"
      end

      unless self.method_defined? "#{field}="
        class_eval code=%{
          def #{field}=(value)
            write_attribute '#{field}', value
          end
        }
      end

      class_eval (code = %{
        def #{field}_with_tracking=(val)
           return if (!self.new_record? && self.#{field} == val)
           updates.add :#{field}, val
        end
        alias_method_chain :#{field}=, :tracking

        def #{field}_with_tracking
          r=updates.for?(:#{field}) ? updates.for(:#{field}) : #{field}_without_tracking
        end
        alias_method_chain :#{field}, :tracking
      })
    end

  end
end

Version data entries

4 entries across 4 versions & 1 rubygems

Version	Path
wagn-1.13.0	mod/core/set/all/attribute_tracking.rb
wagn-1.13.0.pre2	mods/core/sets/all/attribute_tracking.rb
wagn-1.13.0.pre1	mods/core/sets/all/attribute_tracking.rb
wagn-1.13.0.pre	mods/core/sets/all/attribute_tracking.rb