Module: Cerealize::ClassMethods

Defined in:
lib/cerealize.rb,
lib/cerealize/attr_hash.rb

Instance Method Summary collapse

Instance Method Details

#attr_hash(property, attrs) ⇒ Object 



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# File 'lib/cerealize/attr_hash.rb', line 4

def attr_hash property, attrs
  ruby = attrs.inject([]){ |codes, attr|
    codes << <<-RUBY
      def #{attr}
        if #{property}
          #{property}[:#{attr}]
        else
          nil
        end
      end

      def #{attr}= value
        self.#{property} ||= {}

        # this line fixes the quirks in ActiveRecord 2.3.9 at
        # activerecord-2.3.9/lib/active_record/associations/association_collection.rb:L352-L363
        # when we're using associations and STI, thanks Jaime
        # TODO: test for this?
        #{property}_will_change! if
          respond_to?(:#{property}_will_change!) &&
          #{property}[:#{attr}] != value

        #{property}[:#{attr}] = value
      end
    RUBY
  }.join("\n")

  mod = if const_defined?(Cerealize::InternalName)
          const_get(Cerealize::InternalName)
        else
          const_set(Cerealize::InternalName, Module.new)
        end

  mod.module_eval(ruby, __FILE__, __LINE__)
  include mod unless self < mod
end

#cerealize(property, klass = nil, opt = {}) ⇒ Object 



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# File 'lib/cerealize.rb', line 88

def cerealize property, klass=nil, opt={}
  opt[:encoding] ||= :marshal
  cerealize_option[property] =
    opt.merge(:class => klass,
              :codec => Cerealize.codec_get(opt[:encoding]))

  field_orig  = "#{property}_orig"
  field_cache = "#{property}_cache"

  attr_accessor field_orig
  private field_orig, "#{field_orig}="

  mod = if const_defined?(Cerealize::InternalName)
          const_get(Cerealize::InternalName)
        else
          const_set(Cerealize::InternalName, Module.new)
        end

  mod.module_eval <<-RUBY, __FILE__, __LINE__ + 1
    def #{field_cache}
      if defined?(@#{property})
        @#{property}
      else
        # define @#{property} to avoid mutual recursion
        @#{property} = nil
        @#{property} = #{property}
      end
    end

    def #{field_cache}=(new_value)
      @#{property} = new_value
    end
  RUBY

  # Invariants:
  #   - instance_variable_defined?(field_cache)  IFF the READER or WRITER has been called
  #   - instance_variable_defined?(field_pre)    IFF the READER was called BEFORE
  #                                              any WRITER

  # READER method
  #
  mod.module_eval <<-RUBY, __FILE__, __LINE__ + 1
    def #{property}
      # Return cached
      return #{field_cache} if defined?(@#{property}) && #{field_cache}

      # No assignment yet, save property if not already saved
      self.#{field_orig}= self[:#{property}] if !#{field_orig}

      # Set cached from pre
      value = cerealize_decode(:#{property}, #{field_orig})

      raise ActiveRecord::SerializationTypeMismatch, "expected #{klass}, got \#{value.class}" \\
        if #{klass.inspect} && !value.nil? && !value.kind_of?(#{klass})

      self.#{field_cache} = value
    end
  RUBY

  # WRITER method
  #
  mod.module_eval <<-RUBY, __FILE__, __LINE__ + 1
    def #{property}=(value)
      #{property}_will_change! if #{field_cache} != value
      self.#{field_cache} = value
    end
  RUBY

  # Callback for before_save
  #
  mod.module_eval <<-RUBY, __FILE__, __LINE__ + 1
    def #{property}_update_if_dirty
      # See if we have a new cur value
      if instance_variable_defined?('@#{property}')
        value     = #{field_cache}
        value_enc = cerealize_encode(:#{property}, value)

        # See if no orig at all (i.e. it was written to before
        # being read), or if different. When comparing, compare
        # both marshalized string, and Object ==.
        #
        if !#{field_orig} ||
          (value_enc != #{field_orig} &&
           value     != cerealize_decode(:#{property}, #{field_orig}))
          self[:#{property}] = value_enc
        end

        remove_instance_variable('@#{property}')
      end

      self.#{field_orig} = nil
    end
  RUBY

  include mod unless self < mod
  before_save("#{property}_update_if_dirty")
end

#cerealize_update_codec_cache ⇒ Object 



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# File 'lib/cerealize.rb', line 82

def cerealize_update_codec_cache
  cerealize_option.each{ |(property, opt)|
    opt.merge!(:codec => Cerealize.codec_get(opt[:encoding]))
  }
end