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.

1 files changed, 3 insertions, 5 deletions

diff --git a/activesupport/lib/active_support/key_generator.rb b/activesupport/lib/active_support/key_generator.rb
index 6beb2b6afa..71654dbb87 100644
--- a/activesupport/lib/active_support/key_generator.rb
+++ b/activesupport/lib/active_support/key_generator.rb
@@ -1,4 +1,4 @@
-require 'mutex_m'
+require 'thread_safe'
 require 'openssl'
 
 module ActiveSupport
@@ -28,16 +28,14 @@ module ActiveSupport
   class CachingKeyGenerator
     def initialize(key_generator)
       @key_generator = key_generator
-      @cache_keys = {}.extend(Mutex_m)
+      @cache_keys = ThreadSafe::Cache.new
     end
 
     # Returns a derived key suitable for use.  The default key_size is chosen
     # to be compatible with the default settings of ActiveSupport::MessageVerifier.
     # i.e. OpenSSL::Digest::SHA1#block_length
     def generate_key(salt, key_size=64)
-      @cache_keys.synchronize do
-        @cache_keys["#{salt}#{key_size}"] ||= @key_generator.generate_key(salt, key_size)
-      end
+      @cache_keys["#{salt}#{key_size}"] ||= @key_generator.generate_key(salt, key_size)
     end
   end