Implemented db.[collection].count()

README.md

@@ -26,6 +26,7 @@ Then you can do some basic commands:
     > db.things.findOne()
     > db.things.find({a:1})
     > db.things.find({a:1}, {b:1})
+    > db.things.count()
     > db.things.remove({a:1})
     > db.things.remove()
 	> db.things.insert({a:1})

src/riak_mongo_message.erl

@@ -19,6 +19,7 @@
 
 %% @author Kresten Krab Thorup <krab@trifork.com>
 %% @author Pavlo Baron <pb at pbit dot org>
+%% @author Ward Bekker <ward@equanimity.nl>
 %% @doc Here we process all kind of messages
 %% @copyright 2012 Pavlo Baron
 
@@ -35,6 +36,7 @@
 -define(ADM, <<"admin">>).
 -define(DROP, <<"drop">>).
 -define(COLLSTATS, <<"collstats">>).
+-define(COUNT, <<"count">>).
 
 %%
 %% loop over messages
@@ -171,6 +173,9 @@ db_command(DataBase, ?DROP, Collection, _Options, State) ->
 db_command(DataBase, ?COLLSTATS, Collection, _Options, State) ->
     riak_mongo_riak:stats(riak_mongo_protocol:join_dbcoll({DataBase, Collection}), State);
 
+db_command(DataBase, ?COUNT, Collection, _Options, State) ->
+    riak_mongo_riak:count(riak_mongo_protocol:join_dbcoll({DataBase, Collection}), State);
+
 db_command(DataBase, Command, Collection, _Options, State) ->
     error_logger:info_msg("unhandled command: ~p, ~p:~p~n", [Command, DataBase, Collection]),
     {ok, [{err, <<"unknown command: db=", DataBase, ", cmd=", Command/binary>>}, {ok, false}], State}.

src/riak_mongo_protocol.erl

@@ -141,7 +141,6 @@ decode_packet(<< ?HDR(_,OP), _/binary >> = All) ->
     error_logger:info_msg("bad ~w~n", [All]),
     exit({error, {bad_message, RequestId, OP}}).
 
-
 split_dbcoll(Bin) ->
     {Pos, _Len} = binary:match (Bin, <<$.>>),
     <<DB :Pos /binary, $.:8, Coll /binary>> = Bin,

src/riak_mongo_riak.erl

@@ -31,7 +31,7 @@
 
 -compile([{parse_transform, lager_transform}]).
 
--export([insert/2, find/2, getmore/2, delete/2, update/2, stats/2]).
+-export([insert/2, find/2, getmore/2, delete/2, update/2, stats/2, count/2]).
 
 -define(DEFAULT_TIMEOUT, 60000).
 -define(DEFAULT_FIND_SIZE, 101).
@@ -214,6 +214,14 @@ delete(#mongo_delete{dbcoll=Bucket, selector=Selector, singleremove=SingleRemove
             end
     end.
 
+count(Bucket, State) ->
+    {ok, C} = riak:local_client(),
+    {ok, [Count]} = C:mapred(
+                      Bucket,
+                      [riak_kv_mapreduce:reduce_count_inputs(true)]
+                     ),
+    Doc = [{n, Count}],
+    {ok, Doc, State}.
 
 %% internals