From fef82759ff97692470496905951882a0aab49d5b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tobias=20L=C3=BCtke?= <tobi@jadedpixel.com>
Date: Tue, 29 Apr 2008 15:12:47 -0400
Subject: Implement increment/decrement on cache storage engines, using
 read/write by default and using atomic command on memcache

---
 activesupport/lib/active_support/cache.rb              | 17 +++++++++++++++++
 .../lib/active_support/cache/mem_cache_store.rb        | 18 ++++++++++++++++++
 2 files changed, 35 insertions(+)

(limited to 'activesupport/lib')

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"
-- 
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