1 files changed, 69 insertions, 0 deletions
diff --git a/railties/lib/rails/application/routes_reloader.rb b/railties/lib/rails/application/routes_reloader.rb
new file mode 100644
index 0000000000..e02ef629f2
--- /dev/null
+++ b/railties/lib/rails/application/routes_reloader.rb
@@ -0,0 +1,69 @@
+require "active_support/core_ext/module/delegation"
+
+module Rails
+  class Application
+    class RoutesReloader
+      attr_reader :route_sets, :paths
+      attr_accessor :eager_load
+      delegate :updated?, to: :updater
+
+      def initialize
+        @paths      = []
+        @route_sets = []
+        @eager_load = false
+      end
+
+      def reload!
+        clear!
+        load_paths
+        finalize!
+      ensure
+        revert
+      end
+
+      def execute
+        ret = updater.execute
+        route_sets.each(&:eager_load!) if eager_load
+        ret
+      end
+
+      def execute_if_updated
+        if updated = updater.execute_if_updated
+          route_sets.each(&:eager_load!) if eager_load
+        end
+        updated
+      end
+
+    private
+
+      def updater
+        @updater ||= begin
+          updater = ActiveSupport::FileUpdateChecker.new(paths) { reload! }
+          updater.execute
+          updater
+        end
+      end
+
+      def clear!
+        route_sets.each do |routes|
+          routes.disable_clear_and_finalize = true
+          routes.clear!
+        end
+      end
+
+      def load_paths
+        paths.each { |path| load(path) }
+      end
+
+      def finalize!
+        route_sets.each(&:finalize!)
+      end
+
+      def revert
+        route_sets.each do |routes|
+          routes.disable_clear_and_finalize = false
+        end
+      end
+    end
+  end
+end