Add ability to get multiple memcached keys at the same time (via MemCacheStore#read_multi).

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

activesupport/lib/active_support/cache/mem_cache_store.rb

@@ -43,6 +43,11 @@ module ActiveSupport
         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))

activesupport/test/caching_test.rb

@@ -251,6 +251,15 @@ uses_memcached 'memcached backed store' do
       end
     end
 
+    def test_multi_get
+      @cache.with_local_cache do
+        @cache.write('foo', 1)
+        @cache.write('goo', 2)
+        result = @cache.read_multi('foo', 'goo')
+        assert_equal({'foo' => 1, 'goo' => 2}, result)
+      end
+    end
+
     def test_middleware
       app = lambda { |env|
         result = @cache.write('foo', 'bar')