Distinguish options ivar from local; Extract latent Adapter::CachedSerializer

lib/active_model/serializer/adapter/cached_serializer.rb

@@ -0,0 +1,45 @@
+module ActiveModel
+  class Serializer
+    class Adapter
+      class CachedSerializer
+        def initialize(serializer)
+          @cached_serializer = serializer
+          @klass             = @cached_serializer.class
+        end
+
+        def cache_check(adapter_instance)
+          if cached?
+            @klass._cache.fetch(cache_key, @klass._cache_options) do
+              yield
+            end
+          elsif fragment_cached?
+            FragmentCache.new(adapter_instance, @cached_serializer, adapter_instance.instance_options).fetch
+          else
+            yield
+          end
+        end
+
+        def cached?
+          @klass._cache && !@klass._cache_only && !@klass._cache_except
+        end
+
+        def fragment_cached?
+          @klass._cache_only && !@klass._cache_except || !@klass._cache_only && @klass._cache_except
+        end
+
+        def cache_key
+          parts = []
+          parts << object_cache_key
+          parts << @klass._cache_digest unless @klass._cache_options && @klass._cache_options[:skip_digest]
+          parts.join('/')
+        end
+
+        def object_cache_key
+          object_time_safe = @cached_serializer.object.updated_at
+          object_time_safe = object_time_safe.strftime('%Y%m%d%H%M%S%9N') if object_time_safe.respond_to?(:strftime)
+          (@klass._cache_key) ? "#{@klass._cache_key}/#{@cached_serializer.object.id}-#{object_time_safe}" : @cached_serializer.object.cache_key
+        end
+      end
+    end
+  end
+end