Replace some global Hash usages with the new thread safe cache.

Summary of the changes:
 * Add thread_safe gem.
 * Use thread safe cache for digestor caching.
 * Replace manual synchronization with ThreadSafe::Cache in Relation::Delegation.
 * Replace @attribute_method_matchers_cache Hash with ThreadSafe::Cache.
 * Use TS::Cache to avoid the synchronisation overhead on listener retrieval.
 * Replace synchronisation with TS::Cache usage.
 * Use a preallocated array for performance/memory reasons.
 * Update the controllers cache to the new AS::Dependencies::ClassCache API.
   The original @controllers cache no longer makes much sense after @tenderlove's
   changes in 7b6bfe84f3 and f345e2380c.
 * Use TS::Cache in the connection pool to avoid locking overhead.
 * Use TS::Cache in ConnectionHandler.

2 files changed, 7 insertions, 15 deletions

diff --git a/actionpack/lib/action_dispatch/http/filter_parameters.rb b/actionpack/lib/action_dispatch/http/filter_parameters.rb
index 4a7df6b657..4fea690862 100644
--- a/actionpack/lib/action_dispatch/http/filter_parameters.rb
+++ b/actionpack/lib/action_dispatch/http/filter_parameters.rb
@@ -1,4 +1,4 @@
-require 'mutex_m'
+require 'thread_safe'
 require 'active_support/core_ext/hash/keys'
 require 'active_support/core_ext/object/duplicable'
 
@@ -21,7 +21,7 @@ module ActionDispatch
     #   end
     #   => reverses the value to all keys matching /secret/i
     module FilterParameters
-      @@parameter_filter_for  = {}.extend(Mutex_m)
+      @@parameter_filter_for = ThreadSafe::Cache.new
 
       ENV_MATCH = [/RAW_POST_DATA/, "rack.request.form_vars"] # :nodoc:
       NULL_PARAM_FILTER = ParameterFilter.new # :nodoc:
@@ -65,11 +65,7 @@ module ActionDispatch
       end
 
       def parameter_filter_for(filters)
-        @@parameter_filter_for.synchronize do
-          # Do we *actually* need this cache? Constructing ParameterFilters
-          # doesn't seem too expensive.
-          @@parameter_filter_for[filters] ||= ParameterFilter.new(filters)
-        end
+        @@parameter_filter_for[filters] ||= ParameterFilter.new(filters)
       end
 
       KV_RE   = '[^&;=]+'
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 0f95daa790..f60508c022 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -1,5 +1,6 @@
 require 'journey'
 require 'forwardable'
+require 'thread_safe'
 require 'active_support/core_ext/object/to_query'
 require 'active_support/core_ext/hash/slice'
 require 'active_support/core_ext/module/remove_method'
@@ -20,7 +21,7 @@ module ActionDispatch
         def initialize(options={})
           @defaults = options[:defaults]
           @glob_param = options.delete(:glob)
-          @controllers = {}
+          @controller_class_names = ThreadSafe::Cache.new
         end
 
         def call(env)
@@ -68,13 +69,8 @@ module ActionDispatch
       private
 
         def controller_reference(controller_param)
-          controller_name = "#{controller_param.camelize}Controller"
-
-          unless controller = @controllers[controller_param]
-            controller = @controllers[controller_param] =
-              ActiveSupport::Dependencies.reference(controller_name)
-          end
-          controller.get(controller_name)
+          const_name = @controller_class_names[controller_param] ||= "#{controller_param.camelize}Controller"
+          ActiveSupport::Dependencies.constantize(const_name)
         end
 
         def dispatch(controller, action, env)