class ActiveSupport::Cache::MemCacheStore

def decrement(name, amount = 1, options = nil) # :nodoc:

:nodoc:
to zero.
Calling it on a value not stored with :raw will initialize that value
operator and can only be used on values written with the :raw option.
Decrement a cached value. This method uses the memcached decr atomic 
def decrement(name, amount = 1, options = nil) # :nodoc:
  options = merged_options(options)
  response = instrument(:decrement, name, :amount => amount) do
    @data.decr(escape_key(namespaced_key(name, options)), amount)
  end
  response == Response::NOT_FOUND ? nil : response.to_i
rescue MemCache::MemCacheError
  nil
end