make back-ported ShowStatus compatible and use it instead of Rack::ShowStatus

see #190 for details

Author: kares

src/main/java/org/jruby/rack/DefaultRackApplicationFactory.java

@@ -189,7 +189,7 @@ public IRubyObject createErrorApplicationObject(final Ruby runtime) {
         }
         if (errorApp == null) {
             errorApp = "require 'jruby/rack/error_app' \n" +
-            "use Rack::ShowStatus \n" +
+            "use JRuby::Rack::ErrorApp::ShowStatus \n" +
             "run JRuby::Rack::ErrorApp.new";
         }
         runtime.evalScriptlet("load 'jruby/rack/boot/rack.rb'");

src/main/ruby/jruby/rack/error_app.rb

@@ -9,6 +9,8 @@ module JRuby
   module Rack
     class ErrorApp
 
+      autoload :ShowStatus, 'jruby/rack/error_app/show_status'
+
       EXCEPTION = org.jruby.rack.RackEnvironment::EXCEPTION
 
       DEFAULT_RESPONSE_CODE = 500

src/main/ruby/jruby/rack/error_app/show_status.rb

@@ -3,50 +3,44 @@
 require 'rack/utils'
 
 class JRuby::Rack::ErrorApp
-  # Rack::ShowStatus catches all empty responses and replaces them
-  # with a site explaining the error.
-  #
-  # Additional details can be put into <tt>rack.showstatus.detail</tt>
-  # and will be shown as HTML.  If such details exist, the error page
-  # is always rendered, even if the reply was not empty.
 
+  # catches empty responses and replaces them with a site explaining the error.
+  #
+  # @note kindly adapted from on Rack::ShowStatus
   class ShowStatus
+
     def initialize(app)
       @app = app
       @template = ERB.new(TEMPLATE)
     end
 
     def call(env)
       status, headers, body = @app.call(env)
-      headers = Utils::HeaderHash.new(headers)
-      empty = headers[CONTENT_LENGTH].to_i <= 0
+      headers = ::Rack::Utils::HeaderHash.new(headers)
+      empty = headers['Content-Length'].to_i <= 0
 
       # client or server error, or explicit message
       if (status.to_i >= 400 && empty) || env["rack.showstatus.detail"]
-        # This double assignment is to prevent an "unused variable" warning on
-        # Ruby 1.9.3.  Yes, it is dumb, but I don't like Ruby yelling at me.
-        req = req = Rack::Request.new(env)
-
-        message = Rack::Utils::HTTP_STATUS_CODES[status.to_i] || status.to_s
-
-        # This double assignment is to prevent an "unused variable" warning on
-        # Ruby 1.9.3.  Yes, it is dumb, but I don't like Ruby yelling at me.
+        # required erb template variables (captured with binding) :
+        req = req = ::Rack::Request.new(env)
+        message = ::Rack::Utils::HTTP_STATUS_CODES[status.to_i] || status.to_s
         detail = detail = env["rack.showstatus.detail"] || message
 
         body = @template.result(binding)
-        size = Rack::Utils.bytesize(body)
-        [status, headers.merge(CONTENT_TYPE => "text/html", CONTENT_LENGTH => size.to_s), [body]]
+        size = ::Rack::Utils.bytesize(body)
+        [status, headers.merge('Content-Type' => "text/html", 'Content-Length' => size.to_s), [body]]
       else
         [status, headers, body]
       end
     end
 
-    def h(obj)                  # :nodoc:
+    # @private
+    def h(obj)
       case obj
       when String
-        Utils.escape_html(obj)
+        ::Rack::Utils.escape_html(obj)
       else
-        Utils.escape_html(obj.inspect)
+        ::Rack::Utils.escape_html(obj.inspect)
       end
     end
 
@@ -101,7 +95,7 @@ def h(obj)                  # :nodoc:
 
   <div id="explanation">
     <p>
-    You're seeing this error because you use <code>Rack::ShowStatus</code>.
+    You're seeing this error because you use <code>JRuby::Rack::ErrorApp::ShowStatus</code>.
     </p>
   </div>
 </body>

src/spec/ruby/rack/application_spec.rb

@@ -269,8 +269,8 @@ def newRuntime() # use the current runtime instead of creating new
         #expect( rack_app ).to be_a Rack::Handler::Servlet
         expect( rack_app.class.name ).to eql 'Rack::Handler::Servlet'
         app = rack_app.instance_variable_get('@app')
-        expect( app ).to be_a Rack::ShowStatus
-        #expect( app.class.name ).to eql 'Rack::ShowStatus'
+        expect( app ).to be_a JRuby::Rack::ErrorApp::ShowStatus
+        #expect( app.class.name ).to eql 'JRuby::Rack::ErrorApp::ShowStatus'
         error_app = app.instance_variable_get('@app')
         expect( error_app ).to be_a JRuby::Rack::ErrorApp
         #expect( error_app.class.name ).to eql 'JRuby::Rack::ErrorApp'