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.

6 files changed, 98 insertions, 39 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
diff --git a/actionpack/lib/action_dispatch/http/url.rb b/actionpack/lib/action_dispatch/http/url.rb
index 80ffbe575b..f9dae5dad7 100644
--- a/actionpack/lib/action_dispatch/http/url.rb
+++ b/actionpack/lib/action_dispatch/http/url.rb
@@ -40,7 +40,9 @@ module ActionDispatch
             rewritten_url << ":#{options.delete(:port)}" if options[:port]
           end
 
-          path = options.delete(:path) || ''
+          path = ""
+          path << options.delete(:script_name).to_s.chomp("/")
+          path << options.delete(:path).to_s
 
           params = options[:params] || {}
           params.reject! {|k,v| v.to_param.nil? }
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 02a27110e4..80fcdab643 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -446,7 +446,11 @@ module ActionDispatch
             _route = @set.named_routes.routes[name.to_sym]
             _routes = @set
             app.routes.define_mounted_helper(name)
-            app.routes.class_eval do
+            app.routes.singleton_class.class_eval do
+              define_method :mounted? do
+                true
+              end
+
               define_method :_generate_prefix do |options|
                 prefix_options = options.slice(*_route.segment_keys)
                 # we must actually delete prefix segment keys to avoid passing them to next url_for
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 0ec4e41470..c4d87ea3d9 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -191,14 +191,50 @@ module ActionDispatch
             selector = url_helper_name(name, kind)
             hash_access_method = hash_access_name(name, kind)
 
-            @module.module_eval <<-END_EVAL, __FILE__, __LINE__ + 1
-              remove_possible_method :#{selector}
-              def #{selector}(*args)
-                url_for(#{hash_access_method}(*args))
-              end
-            END_EVAL
+            if optimize_helper?(kind, route)
+              @module.module_eval <<-END_EVAL, __FILE__, __LINE__ + 1
+                remove_possible_method :#{selector}
+                def #{selector}(*args)
+                  if args.size == #{route.required_parts.size} && !args.last.is_a?(Hash) && optimize_routes_generation?
+                    options = #{options.inspect}.merge!(url_options)
+                    options[:path] = "#{optimized_helper(route)}"
+                    ActionDispatch::Http::URL.url_for(options)
+                  else
+                    url_for(#{hash_access_method}(*args))
+                  end
+                end
+              END_EVAL
+            else
+              @module.module_eval <<-END_EVAL, __FILE__, __LINE__ + 1
+                remove_possible_method :#{selector}
+                def #{selector}(*args)
+                  url_for(#{hash_access_method}(*args))
+                end
+              END_EVAL
+            end
+
             helpers << selector
           end
+
+          # Clause check about when we need to generate an optimized helper.
+          def optimize_helper?(kind, route) #:nodoc:
+            route.ast.grep(Journey::Nodes::Star).empty? && route.requirements.except(:controller, :action).empty?
+          end
+
+          # Generates the interpolation to be used in the optimized helper.
+          def optimized_helper(route)
+            string_route = route.ast.to_s
+
+            while string_route.gsub!(/\([^\)]*\)/, "")
+              true
+            end
+
+            route.required_parts.each_with_index do |part, i|
+              string_route.gsub!(part.inspect, "\#{Journey::Router::Utils.escape_fragment(args[#{i}].to_param)}")
+            end
+
+            string_route
+          end
       end
 
       attr_accessor :formatter, :set, :named_routes, :default_scope, :router
@@ -323,7 +359,7 @@ module ActionDispatch
             # Rails.application.routes.url_helpers.url_for(args)
             @_routes = routes
             class << self
-              delegate :url_for, :to => '@_routes'
+              delegate :url_for, :optimize_routes_generation?, :to => '@_routes'
             end
 
             # Make named_routes available in the module singleton
@@ -557,6 +593,14 @@ module ActionDispatch
       RESERVED_OPTIONS = [:host, :protocol, :port, :subdomain, :domain, :tld_length,
                           :trailing_slash, :anchor, :params, :only_path, :script_name]
 
+      def mounted?
+        false
+      end
+
+      def optimize_routes_generation?
+        !mounted? && default_url_options.empty?
+      end
+
       def _generate_prefix(options = {})
         nil
       end
@@ -568,19 +612,17 @@ module ActionDispatch
 
         user, password = extract_authentication(options)
         path_segments  = options.delete(:_path_segments)
-        script_name    = options.delete(:script_name)
-
-        path = (script_name.blank? ? _generate_prefix(options) : script_name.chomp('/')).to_s
+        script_name    = options.delete(:script_name).presence || _generate_prefix(options)
 
         path_options = options.except(*RESERVED_OPTIONS)
         path_options = yield(path_options) if block_given?
 
-        path_addition, params = generate(path_options, path_segments || {})
-        path << path_addition
+        path, params = generate(path_options, path_segments || {})
         params.merge!(options[:params] || {})
 
         ActionDispatch::Http::URL.url_for(options.merge!({
           :path => path,
+          :script_name => script_name,
           :params => params,
           :user => user,
           :password => password
diff --git a/actionpack/lib/action_dispatch/routing/url_for.rb b/actionpack/lib/action_dispatch/routing/url_for.rb
index ee6616c5d3..94db36ce1f 100644
--- a/actionpack/lib/action_dispatch/routing/url_for.rb
+++ b/actionpack/lib/action_dispatch/routing/url_for.rb
@@ -102,6 +102,9 @@ module ActionDispatch
         super
       end
 
+      # Hook overriden in controller to add request information
+      # with `default_url_options`. Application logic should not
+      # go into url_options.
       def url_options
         default_url_options
       end
@@ -152,6 +155,11 @@ module ActionDispatch
 
       protected
 
+      def optimize_routes_generation?
+        return @_optimized_routes if defined?(@_optimized_routes)
+        @_optimized_routes = _routes.optimize_routes_generation? && default_url_options.empty?
+      end
+
       def _with_routes(routes)
         old_routes, @_routes = @_routes, routes
         yield
diff --git a/actionpack/lib/action_view/helpers/url_helper.rb b/actionpack/lib/action_view/helpers/url_helper.rb
index 8d7417809b..f4946e65b5 100644
--- a/actionpack/lib/action_view/helpers/url_helper.rb
+++ b/actionpack/lib/action_view/helpers/url_helper.rb
@@ -23,20 +23,25 @@ module ActionView
       include ActionDispatch::Routing::UrlFor
       include TagHelper
 
-      def _routes_context
-        controller
-      end
+      # We need to override url_optoins, _routes_context
+      # and optimize_routes_generation? to consider the controller.
 
-      # Need to map default url options to controller one.
-      # def default_url_options(*args) #:nodoc:
-      #   controller.send(:default_url_options, *args)
-      # end
-      #
-      def url_options
+      def url_options #:nodoc:
         return super unless controller.respond_to?(:url_options)
         controller.url_options
       end
 
+      def _routes_context #:nodoc:
+        controller
+      end
+      protected :_routes_context
+
+      def optimize_routes_generation? #:nodoc:
+        controller.respond_to?(:optimize_routes_generation?) ?
+          controller.optimize_routes_generation? : super
+      end
+      protected :optimize_routes_generation?
+
       # Returns the URL for the set of +options+ provided. This takes the
       # same options as +url_for+ in Action Controller (see the
       # documentation for <tt>ActionController::Base#url_for</tt>). Note that by default