1 files changed, 56 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..3cac03464e
--- /dev/null
+++ b/activerecord/lib/active_record/type/serialized.rb
@@ -0,0 +1,56 @@
+module ActiveRecord
+  module Type
+    class Serialized < DelegateClass(Type::Value) # :nodoc:
+      include Mutable
+      include Decorator
+
+      attr_reader :subtype, :coder
+
+      def initialize(subtype, coder)
+        @subtype = subtype
+        @coder = coder
+        super(subtype)
+      end
+
+      def type_cast_from_database(value)
+        if default_value?(value)
+          value
+        else
+          coder.load(super)
+        end
+      end
+
+      def type_cast_for_database(value)
+        return if value.nil?
+        unless default_value?(value)
+          super coder.dump(value)
+        end
+      end
+
+      def changed_in_place?(raw_old_value, value)
+        return false if value.nil?
+        subtype.changed_in_place?(raw_old_value, type_cast_for_database(value))
+      end
+
+      def accessor
+        ActiveRecord::Store::IndifferentHashAccessor
+      end
+
+      def init_with(coder)
+        @coder = coder['coder']
+        super
+      end
+
+      def encode_with(coder)
+        coder['coder'] = @coder
+        super
+      end
+
+      private
+
+      def default_value?(value)
+        value == coder.load(nil)
+      end
+    end
+  end
+end