Move `type_cast_for_write` behavior over to the serialized type object

2 files changed, 38 insertions, 8 deletions

diff --git a/activerecord/lib/active_record/type/serialized.rb b/activerecord/lib/active_record/type/serialized.rb
index cc7513ca2a..4052ac0fa0 100644
--- a/activerecord/lib/active_record/type/serialized.rb
+++ b/activerecord/lib/active_record/type/serialized.rb
@@ -1,11 +1,12 @@
 module ActiveRecord
   module Type
     class Serialized < SimpleDelegator # :nodoc:
-      attr_reader :subtype
+      attr_reader :subtype, :coder
 
-      def initialize(subtype)
+      def initialize(subtype, coder)
         @subtype = subtype
-        super
+        @coder = coder
+        super(subtype)
       end
 
       def type_cast(value)
@@ -16,6 +17,14 @@ module ActiveRecord
         end
       end
 
+      def type_cast_for_write(value)
+        Attribute.new(coder, value, :unserialized)
+      end
+
+      def raw_type_cast_for_write(value)
+        Attribute.new(coder, value, :serialized)
+      end
+
       def serialized?
         true
       end
@@ -23,6 +32,26 @@ module ActiveRecord
       def accessor
         ActiveRecord::Store::IndifferentHashAccessor
       end
+
+      class Attribute < Struct.new(:coder, :value, :state) # :nodoc:
+        def unserialized_value(v = value)
+          state == :serialized ? unserialize(v) : value
+        end
+
+        def serialized_value
+          state == :unserialized ? serialize : value
+        end
+
+        def unserialize(v)
+          self.state = :unserialized
+          self.value = coder.load(v)
+        end
+
+        def serialize
+          self.state = :serialized
+          self.value = coder.dump(value)
+        end
+      end
     end
   end
 end
diff --git a/activerecord/lib/active_record/type/value.rb b/activerecord/lib/active_record/type/value.rb
index a5493be8f2..9a4adc60cc 100644
--- a/activerecord/lib/active_record/type/value.rb
+++ b/activerecord/lib/active_record/type/value.rb
@@ -23,10 +23,6 @@ module ActiveRecord
         cast_value(value) unless value.nil?
       end
 
-      def type_cast_for_write(value)
-        value
-      end
-
       def type_cast_for_database(value)
         type_cast_for_write(value)
       end
@@ -47,10 +43,15 @@ module ActiveRecord
         false
       end
 
-      def klass
+      def klass # :nodoc:
         ::Object
       end
 
+      def type_cast_for_write(value) # :nodoc:
+        value
+      end
+      alias_method :raw_type_cast_for_write, :type_cast_for_write # :internal:
+
       private
 
       # Responsible for casting values from external sources to the appropriate