Return {ok,CAS::integer()} instead of ok for all store operations.

This saves a roundtrip when you set/add an item that you'll want to modify later.

This is a backward-incompatible change, but it seems important enough and seems to be
a coding oversight as most of the work was already done (but thrown away) in store_callback().

README.md

@@ -53,7 +53,7 @@ cberl:start_link(cberl_default, 5).
 {ok, <0.33.0>}
 % Poolname, Key, Expire - 0 for infinity, Value
 cberl:set(cberl_default, <<"fkey">>, 0, <<"cberl">>).
-ok
+{ok,CAS}
 cberl:get(cberl_default, <<"fkey">>).
 {<<"fkey">>, ReturnedCasValue, <<"cberl">>}
 ```

c_src/cb.c

@@ -181,7 +181,7 @@ ERL_NIF_TERM cb_store(ErlNifEnv* env, handle_t* handle, void* obj)
     if (cb.error != LCB_SUCCESS) {
         return return_lcb_error(env, cb.error);
     }
-    return A_OK(env);
+    return enif_make_tuple2(env, A_OK(env), enif_make_uint64(env, cb.cas));
 }
 
 void* cb_mget_args(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])

src/cberl.erl

@@ -73,32 +73,32 @@ stop(PoolPid) ->
 %%%%%%%%%%%%%%%%%%%%%%%%
 
 %% @equiv add(PoolPid, Key, Exp, Value, standard)
--spec add(pid(), key(), integer(), value()) -> ok | {error, _}.
+-spec add(pid(), key(), integer(), value()) -> {ok,integer()} | {error, _}.
 add(PoolPid, Key, Exp, Value) ->
     add(PoolPid, Key, Exp, Value, standard).
 
 %% @equiv store(PoolPid, add, Key, Value, TranscoderOpts, Exp, 0)
--spec add(pid(), key(), integer(), value(), atom()) -> ok | {error, _}.
+-spec add(pid(), key(), integer(), value(), atom()) -> {ok,integer()} | {error, _}.
 add(PoolPid, Key, Exp, Value, TranscoderOpts) ->
     store(PoolPid, add, Key, Value, TranscoderOpts, Exp, 0).
 
 %% @equiv replace(PoolPid, Key, Exp, Value, standard)
--spec replace(pid(), key(), integer(), value()) -> ok | {error, _}.
+-spec replace(pid(), key(), integer(), value()) -> {ok,integer()} | {error, _}.
 replace(PoolPid, Key, Exp, Value) ->
     replace(PoolPid, Key, Exp, Value, standard).
 
 %% @equiv store(PoolPid, replace, "", Key, Value, Exp)
--spec replace(pid(), key(), integer(), value(), atom()) -> ok | {error, _}.
+-spec replace(pid(), key(), integer(), value(), atom()) -> {ok,integer()} | {error, _}.
 replace(PoolPid, Key, Exp, Value, TranscoderOpts) ->
     store(PoolPid, replace, Key, Value, TranscoderOpts, Exp, 0).
 
 %% @equiv set(PoolPid, Key, Exp, Value, standard)
--spec set(pid(), key(), integer(), value()) -> ok | {error, _}.
+-spec set(pid(), key(), integer(), value()) -> {ok,integer()} | {error, _}.
 set(PoolPid, Key, Exp, Value) ->
     set(PoolPid, Key, Exp, Value, standard).
 
 %% @equiv store(PoolPid, set, "", Key, Value, Exp)
--spec set(pid(), key(), integer(), value(), atom()) -> ok | {error, _}.
+-spec set(pid(), key(), integer(), value(), atom()) -> {ok,integer()} | {error, _}.
 set(PoolPid, Key, Exp, Value, TranscoderOpts) ->
     store(PoolPid, set, Key, Value, TranscoderOpts, Exp, 0).
 
@@ -113,7 +113,7 @@ set(PoolPid, Key, Exp, Value, TranscoderOpts) ->
 append(PoolPid, _Cas, Key, Value) ->
     append(PoolPid, Key, Value).
 
--spec append(pid(), key(), value()) -> ok | {error, _}.
+-spec append(pid(), key(), value()) -> {ok,integer()} | {error, _}.
 append(PoolPid, Key, Value) ->
     store(PoolPid, append, Key, Value, none, 0, 0).
 
@@ -124,7 +124,7 @@ append(PoolPid, Key, Value) ->
 prepend(PoolPid, _Cas, Key, Value) ->
     prepend(PoolPid, Key, Value).
 
--spec prepend(pid(), key(), value()) -> ok | {error, _}.
+-spec prepend(pid(), key(), value()) -> {ok,integer()} | {error, _}.
 prepend(PoolPid, Key, Value) ->
     store(PoolPid, prepend, Key, Value, none, 0, 0).
 
@@ -212,7 +212,7 @@ unlock(PoolPid, Key, Cas) ->
 %%     pass 0 for infinity
 %% CAS
 -spec store(pid(), operation_type(), key(), value(), atom(),
-            integer(), integer()) -> ok | {error, _}.
+            integer(), integer()) -> {ok,integer()} | {error, _}.
 store(PoolPid, Op, Key, Value, TranscoderOpts, Exp, Cas) ->
     execute(PoolPid, {store, Op, Key, Value,
                        TranscoderOpts, Exp, Cas}).