Use a custom route vistor for optimized route generation

Using a Regexp to replace dynamic segments in a path string is fraught
with difficulty and can lead to odd edge cases like #13349. Since we
already have a parsed representation of the path it makes sense to use
that to generate an array of segments that can be used to build an
optimized route's path quickly.

Tests on a simple route (e.g. /posts/:id) show a speedup of 35%:
https://gist.github.com/pixeltrix/8261932

Calculating -------------------------------------
    Current Helper:       5274 i/100ms
    New Helper:           8050 i/100ms
-------------------------------------------------
    Current Helper:     79263.6 (±3.7%) i/s -     395550 in   4.997252s
    New Helper:        153464.5 (±4.9%) i/s -     772800 in   5.047834s

Tests on a more complex route show even an greater performance boost:
https://gist.github.com/pixeltrix/8261957

Calculating -------------------------------------
    Current Helper:       2367 i/100ms
    New Helper:           5382 i/100ms
-------------------------------------------------
    Current Helper:     29506.0 (±3.2%) i/s -     149121 in   5.059294s
    New Helper:         78815.5 (±4.1%) i/s -     398268 in   5.062161s

It also has the added benefit of fixing the edge cases described above.

Fixes #13349

1 files changed, 12 insertions, 0 deletions

diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index aac808afda..fad09d309a 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -3327,6 +3327,8 @@ class TestOptimizedNamedRoutes < ActionDispatch::IntegrationTest
       ok = lambda { |env| [200, { 'Content-Type' => 'text/plain' }, []] }
       get '/foo' => ok, as: :foo
       get '/post(/:action(/:id))' => ok, as: :posts
+      get '/:foo/:foo_type/bars/:id' => ok, as: :bar
+      get '/projects/:id.:format' => ok, as: :project
     end
   end
 
@@ -3349,6 +3351,16 @@ class TestOptimizedNamedRoutes < ActionDispatch::IntegrationTest
     assert_equal '/post', Routes.url_helpers.posts_path
     assert_equal '/post', posts_path
   end
+
+  test 'segments with same prefix are replaced correctly' do
+    assert_equal '/foo/baz/bars/1', Routes.url_helpers.bar_path('foo', 'baz', '1')
+    assert_equal '/foo/baz/bars/1', bar_path('foo', 'baz', '1')
+  end
+
+  test 'segments separated with a period are replaced correctly' do
+    assert_equal '/projects/1.json', Routes.url_helpers.project_path(1, :json)
+    assert_equal '/projects/1.json', project_path(1, :json)
+  end
 end
 
 class TestNamedRouteUrlHelpers < ActionDispatch::IntegrationTest