2 files changed, 19 insertions, 7 deletions
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
index 4d8e1fdd67..38b3409ca6 100644
--- a/activesupport/lib/active_support/cache/mem_cache_store.rb
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -23,7 +23,12 @@ module ActiveSupport
         DELETED     = "DELETED\r\n"
       end
 
-      attr_reader :addresses
+      def self.build_mem_cache(*addresses)
+        addresses = addresses.flatten
+        options = addresses.extract_options!
+        addresses = ["localhost"] if addresses.empty?
+        MemCache.new(addresses, options)
+      end
 
       # Creates a new MemCacheStore object, with the given memcached server
       # addresses. Each address is either a host name, or a host-with-port string
@@ -34,15 +39,20 @@ module ActiveSupport
       # If no addresses are specified, then MemCacheStore will connect to
       # localhost port 11211 (the default memcached port).
       def initialize(*addresses)
-        addresses = addresses.flatten
-        options = addresses.extract_options!
-        addresses = ["localhost"] if addresses.empty?
-        @addresses = addresses
-        @data = MemCache.new(addresses, options)
+        if addresses.first.respond_to?(:get)
+          @data = addresses.first
+        else
+          @data = self.class.build_mem_cache(*addresses)
+        end
 
         extend Strategy::LocalCache
       end
 
+      # Reads multiple keys from the cache.
+      def read_multi(*keys)
+        @data.get_multi keys
+      end
+
       def read(key, options = nil) # :nodoc:
         super
         @data.get(key, raw?(options))
diff --git a/activesupport/lib/active_support/cache/strategy/local_cache.rb b/activesupport/lib/active_support/cache/strategy/local_cache.rb
index 84d9a0e6d8..3b5fccc737 100644
--- a/activesupport/lib/active_support/cache/strategy/local_cache.rb
+++ b/activesupport/lib/active_support/cache/strategy/local_cache.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/object/duplicable'
+
 module ActiveSupport
   module Cache
     module Strategy
@@ -43,7 +45,7 @@ module ActiveSupport
           elsif value.nil?
             value = super
             local_cache.write(key, value || NULL) if local_cache
-            value
+            value.duplicable? ? value.dup : value
           else
             # forcing the value to be immutable
             value.duplicable? ? value.dup : value