From af597b37a628a7f24d0370457c97aa45785daf8a Mon Sep 17 00:00:00 2001
From: Aliaksey Kandratsenka <alk@tut.by>
Date: Thu, 2 Oct 2008 21:06:22 +0300
Subject: [PATCH] Return processing lock to dispatcher. This fixes class reloading race in development mode.

Without this fix class reloading is unguarded and our app easily hits this race.

This commit also adds ActionController::Dispatcher#dispatch_unlocking -- non-locking version of dispatch.
It's named anologously to POSIX {getc,getchar,...}_unlocked functions.

This partially reverts commit 19db0b732458347b5237ac90865d62b3fd2157f1 "Added back ActionController::Base.allow_concurrency flag and moved lock down to controller processing."
---
 actionpack/lib/action_controller/base.rb       |    9 +--------
 actionpack/lib/action_controller/dispatcher.rb |   14 +++++++++++++-
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
index 976bd98..e99e828 100644
--- a/actionpack/lib/action_controller/base.rb
+++ b/actionpack/lib/action_controller/base.rb
@@ -290,8 +290,6 @@ module ActionController #:nodoc:
     @@allow_concurrency = false
     cattr_accessor :allow_concurrency
 
-    @@guard = Monitor.new
-
     # Modern REST web services often need to submit complex data to the web application.
     # The <tt>@@param_parsers</tt> hash lets you register handlers which will process the HTTP body and add parameters to the
     # <tt>params</tt> hash. These handlers are invoked for POST and PUT requests.
@@ -532,12 +530,7 @@ module ActionController #:nodoc:
         assign_names
 
         log_processing
-
-        if @@allow_concurrency
-          send(method, *arguments)
-        else
-          @@guard.synchronize { send(method, *arguments) }
-        end
+        send(method, *arguments)
 
         send_response
       ensure
diff --git a/actionpack/lib/action_controller/dispatcher.rb b/actionpack/lib/action_controller/dispatcher.rb
index 106d960..90c8400 100644
--- a/actionpack/lib/action_controller/dispatcher.rb
+++ b/actionpack/lib/action_controller/dispatcher.rb
@@ -2,6 +2,8 @@ module ActionController
   # Dispatches requests to the appropriate controller and takes care of
   # reloading the app after each request when Dependencies.load? is true.
   class Dispatcher
+    @@guard = Mutex.new
+
     class << self
       def define_dispatcher_callbacks(cache_classes)
         unless cache_classes
@@ -99,7 +101,7 @@ module ActionController
       @output, @request, @response = output, request, response
     end
 
-    def dispatch
+    def dispatch_unlocked
       begin
         run_callbacks :before_dispatch
         handle_request
@@ -110,6 +112,16 @@ module ActionController
       end
     end
 
+    def dispatch
+      if ActionController::Base.allow_concurrency
+        dispatch_unlocked
+      else
+        @@guard.synchronize do
+          dispatch_unlocked
+        end
+      end
+    end
+
     def dispatch_cgi(cgi, session_options)
       if cgi ||= self.class.failsafe_response(@output, '400 Bad Request') { CGI.new }
         @request = CgiRequest.new(cgi, session_options)
-- 
1.5.6.5