allowing use of CAS property in set

For situations where you don't want to replace a value if the record has been modified since the last read a CAS value is passed from the last read.

src/cberl.erl

@@ -9,7 +9,7 @@
 -export([start_link/2, start_link/3, start_link/5, start_link/6, start_link/7]).
 -export([stop/1]).
 %% store operations
--export([add/4, add/5, replace/4, replace/5, set/4, set/5, store/7]).
+-export([add/4, add/5, replace/4, replace/5, set/4, set/5, set/6, store/7]).
 %% update operations
 -export([append/3, prepend/3, touch/3, mtouch/3]).
 -export([incr/3, incr/4, incr/5, decr/3, decr/4, decr/5]).
@@ -101,6 +101,13 @@ set(PoolPid, Key, Exp, Value) ->
 set(PoolPid, Key, Exp, Value, TranscoderOpts) ->
     store(PoolPid, set, Key, Value, TranscoderOpts, Exp, 0).
 
+
+%% @equiv store(PoolPid, set, "", Key, Value, Exp)
+-spec set(pid(), key(), integer(), value(), atom(), integer()) -> ok | {error, _}.
+set(PoolPid, Key, Exp, Value, TranscoderOpts, Cas) ->
+    store(PoolPid, set, Key, Value, TranscoderOpts, Exp, Cas).
+
+
 %%%%%%%%%%%%%%%%%%%%%%%%%
 %%% UPDATE OPERATIONS %%%
 %%%%%%%%%%%%%%%%%%%%%%%%%

test/cberl_tests.erl

@@ -5,6 +5,7 @@
 cberl_test_() ->
     [{foreach, fun setup/0, fun clean_up/1,
       [fun test_set_and_get/1,
+       fun test_set_cas/1,
        fun test_replace_add/1,
        fun test_multi_get/1,
        fun test_get_and_touch/1,
@@ -51,6 +52,26 @@ test_set_and_get(_) ->
      ?_assertMatch({Key, _, Value}, Get3)
     ].
 
+test_set_cas(_) ->
+    Key = <<"testkey">>,
+    Value = "testval",
+    Value2 = "testval2",
+    Value3 = "testval3",
+    ok = cberl:set(?POOLNAME, Key, 0, Value), 
+    {_, Cas1, _} = cberl:get(?POOLNAME, Key),
+    ok = cberl:set(?POOLNAME, Key, 0, Value2, standard, Cas1),
+    {_, Cas2, Value2} = cberl:get(?POOLNAME, Key),
+    SetFail = cberl:set(?POOLNAME, Key, 0, Value3, standard, Cas1),
+    {_, Cas2, Value3failed} = cberl:get(?POOLNAME, Key),
+    ok = cberl:set(?POOLNAME, Key, 0, Value3, standard, Cas2),
+    {_, _, Value3Success} = cberl:get(?POOLNAME, Key),
+    [?_assertEqual({error, key_eexists}, SetFail),
+     ?_assertEqual(Value3failed, Value2),
+     ?_assertEqual(Value3Success, Value3)
+    ].
+
+
+
 test_multi_get(_) ->
     Value = "testval",
     Keys = lists:map(fun(N) -> list_to_binary(integer_to_list(N)) end, lists:seq(1, 1000)),