Merge pull request #5242 from rails/opt_routes

Optimize routes generation in simple cases.

If you pass to the route helper the same amount of arguments
as the required segments, route generation will be optimized
as a string interpolation. After this commit, `post_path(post)`
is about 6.5 times faster, `post_url(post)` is about 5 times.

1 files changed, 14 insertions, 16 deletions

diff --git a/actionpack/lib/action_controller/metal/url_for.rb b/actionpack/lib/action_controller/metal/url_for.rb
index 0b40b1fc4c..4504d9cd10 100644
--- a/actionpack/lib/action_controller/metal/url_for.rb
+++ b/actionpack/lib/action_controller/metal/url_for.rb
@@ -1,7 +1,7 @@
-# Includes +url_for+ into the host class. The class has to provide a +RouteSet+ by implementing 
+# Includes +url_for+ into the host class. The class has to provide a +RouteSet+ by implementing
 # the <tt>_routes</tt> method. Otherwise, an exception will be raised.
 #
-# In addition to <tt>AbstractController::UrlFor</tt>, this module accesses the HTTP layer to define 
+# In addition to <tt>AbstractController::UrlFor</tt>, this module accesses the HTTP layer to define
 # url options like the +host+. In order to do so, this module requires the host class
 # to implement +env+ and +request+, which need to be a Rack-compatible.
 #
@@ -18,7 +18,7 @@
 #       @url        = root_path # named route from the application.
 #     end
 #   end
-# 
+#
 module ActionController
   module UrlFor
     extend ActiveSupport::Concern
@@ -26,22 +26,20 @@ module ActionController
     include AbstractController::UrlFor
 
     def url_options
-      @_url_options ||= super.reverse_merge(
-        :host => request.host,
-        :port => request.optional_port,
-        :protocol => request.protocol,
-        :_path_segments => request.symbolized_path_parameters
-      ).freeze
+      @_url_options ||= begin
+        hash = super.reverse_merge(
+          :host => request.host,
+          :port => request.optional_port,
+          :protocol => request.protocol,
+          :_path_segments => request.symbolized_path_parameters
+        )
 
-      if _routes.equal?(env["action_dispatch.routes"])
-        @_url_options.dup.tap do |options|
-          options[:script_name] = request.script_name.dup
-          options.freeze
+        if _routes.equal?(env["action_dispatch.routes"])
+          hash[:script_name] = request.script_name.dup
         end
-      else
-        @_url_options
+
+        hash.freeze
       end
     end
-
   end
 end