1 files changed, 51 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/type/serialized.rb b/activerecord/lib/active_record/type/serialized.rb
new file mode 100644
index 0000000000..42bbed7103
--- /dev/null
+++ b/activerecord/lib/active_record/type/serialized.rb
@@ -0,0 +1,51 @@
+module ActiveRecord
+  module Type
+    class Serialized < SimpleDelegator # :nodoc:
+      include Mutable
+
+      attr_reader :subtype, :coder
+
+      def initialize(subtype, coder)
+        @subtype = subtype
+        @coder = coder
+        super(subtype)
+      end
+
+      def type_cast_from_database(value)
+        if is_default_value?(value)
+          value
+        else
+          coder.load(super)
+        end
+      end
+
+      def type_cast_for_database(value)
+        return if value.nil?
+        unless is_default_value?(value)
+          super coder.dump(value)
+        end
+      end
+
+      def accessor
+        ActiveRecord::Store::IndifferentHashAccessor
+      end
+
+      def init_with(coder)
+        @subtype = coder['subtype']
+        @coder = coder['coder']
+        __setobj__(@subtype)
+      end
+
+      def encode_with(coder)
+        coder['subtype'] = @subtype
+        coder['coder'] = @coder
+      end
+
+      private
+
+      def is_default_value?(value)
+        value == coder.load(nil)
+      end
+    end
+  end
+end