From 6ce4b4303543eed6f2c323dcaae291bacfeb4d2c Mon Sep 17 00:00:00 2001
From: Jeremy Kemper <jeremy@bitsweat.net>
Date: Thu, 18 Dec 2008 16:55:03 -0800
Subject: [PATCH] Cheaper metal cascade

---
 railties/lib/rails/rack/cascade.rb | 31 +++++++++++++++++++++++++++++
 railties/lib/rails/rack/metal.rb   | 32 ++++++++++++++++++++----------
 2 files changed, 52 insertions(+), 11 deletions(-)
 create mode 100644 railties/lib/rails/rack/cascade.rb

diff --git a/railties/lib/rails/rack/cascade.rb b/railties/lib/rails/rack/cascade.rb
new file mode 100644
index 0000000000..d5af7fc77e
--- /dev/null
+++ b/railties/lib/rails/rack/cascade.rb
@@ -0,0 +1,31 @@
+require 'active_support/ordered_hash'
+
+module Rails
+  module Rack
+    # Try a request on several apps; return the first non-404 response.
+    class Cascade
+      attr_reader :apps
+
+      def initialize(apps)
+        @apps = ActiveSupport::OrderedHash.new
+        apps.each { |app| add app }
+      end
+
+      def call(env)
+        @apps.keys.each do |app|
+          result = app.call(env)
+          return result unless result[0].to_i == 404
+        end
+        Metal::NotFoundResponse
+      end
+
+      def add(app)
+        @apps[app] = true
+      end
+
+      def include?(app)
+        @apps.include?(app)
+      end
+    end
+  end
+end
diff --git a/railties/lib/rails/rack/metal.rb b/railties/lib/rails/rack/metal.rb
index 77d00ab091..1df31a1594 100644
--- a/railties/lib/rails/rack/metal.rb
+++ b/railties/lib/rails/rack/metal.rb
@@ -1,17 +1,27 @@
+require 'rails/rack/cascade'
+
 module Rails
   module Rack
-    class Metal
-      def self.new(app)
-        apps = Dir["#{Rails.root}/app/metal/*.rb"].map do |file|
-          File.basename(file, '.rb').camelize.constantize
-        end
-        apps << app
-        ::Rack::Cascade.new(apps)
-      end
+    module Metal
+      NotFoundResponse = [404, {}, []].freeze
+      NotFound = lambda { NotFoundResponse }
 
-      NotFound = lambda { |env|
-        [404, {"Content-Type" => "text/html"}, "Not Found"]
-      }
+      class << self
+        def new(app)
+          Cascade.new(builtins + [app])
+        end
+
+        def builtins
+          base = "#{Rails.root}/app/metal"
+          matcher = /\A#{Regexp.escape(base)}\/(.*)\.rb\Z/
+
+          Dir["#{base}/**/*.rb"].sort.map do |file|
+            file.sub!(matcher, '\1')
+            require file
+            file.classify.constantize
+          end
+        end
+      end
     end
   end
 end