MemoryStore is the only "unsafe" store. Make it threadsafe by default.

actionpack/lib/action_view/helpers/asset_tag_helper.rb

@@ -463,7 +463,7 @@ def image_tag(source, options = {})
       end
 
       private
-        COMPUTED_PUBLIC_PATHS = ActiveSupport::Cache::MemoryStore.new.silence!.threadsafe!
+        COMPUTED_PUBLIC_PATHS = ActiveSupport::Cache::MemoryStore.new.silence!
 
         # Add the the extension +ext+ if not present. Return full URLs otherwise untouched.
         # Prefix with <tt>/dir/</tt> if lacking a leading +/+. Account for relative URL

activesupport/lib/active_support/cache.rb

@@ -39,10 +39,6 @@ def self.expand_cache_key(key, namespace = nil)
     class Store
       cattr_accessor :logger
 
-      def threadsafe!
-        extend ThreadSafety
-      end
-
       def silence!
         @silence = true
         self
@@ -115,20 +111,6 @@ def log(operation, key, options)
           logger.debug("Cache #{operation}: #{key}#{options ? " (#{options.inspect})" : ""}") if logger && !@silence && !@logger_off
         end
     end
-
-    module ThreadSafety #:nodoc:
-      def self.extended(object) #:nodoc:
-        object.instance_variable_set(:@mutex, Mutex.new)
-      end
-
-      %w(read write delete delete_matched exist? increment decrement).each do |method|
-        module_eval <<-EOS, __FILE__, __LINE__
-          def #{method}(*args)
-            @mutex.synchronize { super }
-          end
-        EOS
-      end
-    end
   end
 end
 

activesupport/lib/active_support/cache/memory_store.rb

@@ -3,36 +3,67 @@ module Cache
     class MemoryStore < Store
       def initialize
         @data = {}
+        @mutex = Mutex.new
+      end
+
+      def fetch(key, options = {})
+        @mutex.synchronize do
+          super
+        end
       end
 
       def read(name, options = nil)
-        super
-        @data[name]
+        @mutex.synchronize do
+          super
+          @data[name]
+        end
       end
 
       def write(name, value, options = nil)
-        super
-        @data[name] = value
+        @mutex.synchronize do
+          super
+          @data[name] = value
+        end
       end
 
       def delete(name, options = nil)
-        super
-        @data.delete(name)
+        @mutex.synchronize do
+          super
+          @data.delete(name)
+        end
       end
 
       def delete_matched(matcher, options = nil)
-        super
-        @data.delete_if { |k,v| k =~ matcher }
+        @mutex.synchronize do
+          super
+          @data.delete_if { |k,v| k =~ matcher }
+        end
       end
 
       def exist?(name,options = nil)
-        super
-        @data.has_key?(name)
+        @mutex.synchronize do
+          super
+          @data.has_key?(name)
+        end
+      end
+
+      def increment(key, amount = 1)
+        @mutex.synchronize do
+          super
+        end
+      end
+
+      def decrement(key, amount = 1)
+        @mutex.synchronize do
+          super
+        end
       end
 
       def clear
-        @data.clear
+        @mutex.synchronize do
+          @data.clear
+        end
       end
     end
   end
-end
+end

activesupport/test/caching_test.rb

@@ -70,70 +70,3 @@ def test_fetch_with_forced_cache_miss
     end
   end
 end
-
-class ThreadSafetyCacheStoreTest < Test::Unit::TestCase
-  def setup
-    @cache = ActiveSupport::Cache.lookup_store(:memory_store).threadsafe!
-    @cache.write('foo', 'bar')
-
-    # No way to have mocha proxy to the original method
-    @mutex = @cache.instance_variable_get(:@mutex)
-    @mutex.instance_eval %(
-      def calls; @calls; end
-      def synchronize
-        @calls ||= 0
-        @calls += 1
-        yield
-      end
-    )
-  end
-
-  def test_read_is_synchronized
-    assert_equal 'bar', @cache.read('foo')
-    assert_equal 1, @mutex.calls
-  end
-
-  def test_write_is_synchronized
-    @cache.write('foo', 'baz')
-    assert_equal 'baz', @cache.read('foo')
-    assert_equal 2, @mutex.calls
-  end
-
-  def test_delete_is_synchronized
-    assert_equal 'bar', @cache.read('foo')
-    @cache.delete('foo')
-    assert_equal nil, @cache.read('foo')
-    assert_equal 3, @mutex.calls
-  end
-
-  def test_delete_matched_is_synchronized
-    assert_equal 'bar', @cache.read('foo')
-    @cache.delete_matched(/foo/)
-    assert_equal nil, @cache.read('foo')
-    assert_equal 3, @mutex.calls
-  end
-
-  def test_fetch_is_synchronized
-    assert_equal 'bar', @cache.fetch('foo') { 'baz' }
-    assert_equal 'fu', @cache.fetch('bar') { 'fu' }
-    assert_equal 3, @mutex.calls
-  end
-
-  def test_exist_is_synchronized
-    assert @cache.exist?('foo')
-    assert !@cache.exist?('bar')
-    assert_equal 2, @mutex.calls
-  end
-
-  def test_increment_is_synchronized
-    @cache.write('foo_count', 1)
-    assert_equal 2, @cache.increment('foo_count')
-    assert_equal 4, @mutex.calls
-  end
-
-  def test_decrement_is_synchronized
-    @cache.write('foo_count', 1)
-    assert_equal 0, @cache.decrement('foo_count')
-    assert_equal 4, @mutex.calls
-  end
-end

railties/lib/initializer.rb

@@ -776,7 +776,6 @@ def threadsafe!
       self.dependency_loading = false
       self.active_record.allow_concurrency = true
       self.action_controller.allow_concurrency = true
-      self.to_prepare { Rails.cache.threadsafe! }
       self
     end