Implement increment/decrement on cache storage engines, using read/write by default and using atomic command on memcache

3 files changed, 37 insertions, 3 deletions

diff --git a/actionpack/test/controller/session/mem_cache_store_test.rb b/actionpack/test/controller/session/mem_cache_store_test.rb
index df48e6d9c5..a7d48431f8 100644
--- a/actionpack/test/controller/session/mem_cache_store_test.rb
+++ b/actionpack/test/controller/session/mem_cache_store_test.rb
@@ -62,9 +62,8 @@ class MemCacheStoreTest < Test::Unit::TestCase
       assert_equal d, s.cache.get(session_key)[:test]
       assert_equal d, s[:test]
     end
-  end
-
-
+  end         
+  
   def test_deletion
     new_session do |s|
       session_key = 'session:' + s.session_id
diff --git a/activesupport/lib/active_support/cache.rb b/activesupport/lib/active_support/cache.rb
index 64394afec4..463cba6cf0 100644
--- a/activesupport/lib/active_support/cache.rb
+++ b/activesupport/lib/active_support/cache.rb
@@ -87,8 +87,25 @@ module ActiveSupport
 
       def delete_matched(matcher, options = nil)
         log("delete matched", matcher.inspect, options)
+      end       
+      
+      def increment(key, amount = 1)
+        log("incrementing", key, amount)
+        if num = read(key)
+          write(key, num + amount)
+        else
+          nil
+        end
       end
 
+      def decrement(key, amount = 1)
+        log("decrementing", key, amount)
+        if num = read(key)
+          write(key, num - amount)
+        else
+          nil
+        end
+      end
       
       private
         def log(operation, key, options)
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
index ad220a9c2c..15e2df13b3 100644
--- a/activesupport/lib/active_support/cache/mem_cache_store.rb
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -48,8 +48,26 @@ module ActiveSupport
       rescue MemCache::MemCacheError => e
         logger.error("MemCacheError (#{e}): #{e.message}")
         false
+      end              
+
+      def increment(key, amount = 1)       
+        log("incrementing", key, amount)
+        
+        response = @data.incr(key, amount)  
+        response == Response::NOT_FOUND ? nil : response
+      rescue MemCache::MemCacheError 
+        nil
       end
 
+      def decrement(key, amount = 1)
+        log("decrement", key, amount)
+        
+        response = data.decr(key, amount) 
+        response == Response::NOT_FOUND ? nil : response
+      rescue MemCache::MemCacheError 
+        nil
+      end        
+      
       def delete_matched(matcher, options = nil)
         super
         raise "Not supported by Memcache"