From 74609e6294a344173fc3ed5e12502a504a24ce65 Mon Sep 17 00:00:00 2001
From: Valery Tikhonov <com.tihon@mail.ru>
Date: Thu, 29 May 2014 17:29:14 +0300
Subject: [PATCH] change orddict to ets, refactor process requests

---
 src/connection/mc_worker.erl | 53 ++++++++++++++++++------------------
 1 file changed, 27 insertions(+), 26 deletions(-)

diff --git a/src/connection/mc_worker.erl b/src/connection/mc_worker.erl
index 8b86a98b..743c9520 100644
--- a/src/connection/mc_worker.erl
+++ b/src/connection/mc_worker.erl
@@ -17,7 +17,7 @@
 
 -record(state, {
 	socket :: gen_tcp:socket(),
-	requests :: orddict:orddict(),  %TODO ets me?
+	ets,
 	buffer :: binary(),
 	conn_state
 }).
@@ -40,7 +40,8 @@ init([{Host, Port}, Options]) ->
 	{ok, Socket} = connect_to_database(Host, Port, Options),
 	State = proplists:get_value(state, Options),
 	process_flag(trap_exit, true),
-	{ok, #state{socket = Socket, requests = [], buffer = <<>>, conn_state = State}}.
+	RequestStorage = ets:new(requests, [private]),
+	{ok, #state{socket = Socket, ets = RequestStorage, buffer = <<>>, conn_state = State}}.
 
 %% @hidden
 handle_call(NewState = #conn_state, _, State = #state{conn_state = OldState}) ->  % update state, return old
@@ -78,11 +79,12 @@ handle_call(Request, _, State = #state{socket = Socket, conn_state = ConnState#c
 	{Packet, _Id} = encode_request(ConnState#conn_state.database, Request),
 	ok = gen_tcp:send(Socket, Packet),
 	{reply, ok, State};
-handle_call(Request, From, State = #state{socket = Socket, conn_state = ConnState})
-	when is_record(Request, 'query'); is_record(Request, getmore) ->                           % read requests
-	{ok, Id} = make_request(Socket, ConnState#conn_state.database, Request),  %TODO how to get data from mongo?
+handle_call(Request, From, State = #state{socket = Socket, conn_state = ConnState, ets = Ets})
+	when is_record(Request, 'query'); is_record(Request, getmore) ->                             % read requests
+	{ok, Id} = make_request(Socket, ConnState#conn_state.database, Request),
 	inet:setopts(Socket, [{active, once}]),
-	{noreply, State#state{requests = [{Id, From} | State#state.requests]}}; % TODO saving big data in record? %TODO why only read?
+	true = ets:insert_new(Ets, {Id, From}),
+	{noreply, State};
 handle_call({request, Request}, _, State = #state{socket = Socket, conn_state = ConnState}) -> % ordinary requests
 	{ok, _} = make_request(Socket, ConnState#conn_state.database, Request),
 	{reply, ok, State};
@@ -94,17 +96,15 @@ handle_cast(_, State) ->
 	{noreply, State}.
 
 %% @hidden
-handle_info({tcp, _Socket, Data}, State) ->
+handle_info({tcp, _Socket, Data}, State = #state{ets = Ets}) ->
 	Buffer = <<(State#state.buffer)/binary, Data/binary>>,
 	{Responses, Pending} = decode_responses(Buffer),
-	Request = case process_responses(Responses, State#state.requests) of
-		          [] ->
-			          [];
-		          Requests ->
-			          inet:setopts(State#state.socket, [{active, once}]),
-			          Requests
-	          end,
-	{noreply, State#state{requests = Request, buffer = Pending}};
+	process_responses(Responses, Ets),
+	case proplists:get_value(size, ets:info(Ets)) of
+		0 -> ok;
+		_ -> inet:setopts(State#state.socket, [{active, once}])
+	end,
+	{noreply, State#state{buffer = Pending}};
 handle_info({tcp_closed, _Socket}, State) ->
 	{stop, tcp_closed, State};
 handle_info({tcp_error, _Socket, Reason}, State) ->
@@ -126,7 +126,7 @@ encode_request(Database, Request) ->
 	{<<(byte_size(Payload) + 4):32/little, Payload/binary>>, RequestId}.
 
 %% @private
-decode_responses(Data) -> %TODO move me to mc_connection_man?
+decode_responses(Data) ->
 	decode_responses(Data, []).
 
 %% @private
@@ -139,16 +139,17 @@ decode_responses(Data, Acc) ->
 	{lists:reverse(Acc), Data}.
 
 %% @private
-process_responses([], Requests) -> Requests;
-process_responses([{Id, Response} | RemainingResponses], Requests) ->
-	case lists:keytake(Id, 1, Requests) of
-		false ->
-			% TODO: close any cursor that might be linked to this request ?
-			process_responses(RemainingResponses, Requests);
-		{value, {_Id, From}, RemainingRequests} ->
-			gen_server:reply(From, Response),
-			process_responses(RemainingResponses, RemainingRequests)
-	end.
+process_responses(Responses, Ets) ->
+	lists:foreach(
+		fun({Id, Response}) ->
+			case ets:lookup(Ets, Id) of
+				[] -> % TODO: close any cursor that might be linked to this request ?
+					ok;
+				[{Id, From}] ->
+					ets:delete(Ets, Id),
+					gen_server:reply(From, Response)
+			end
+		end, Responses).
 
 %% @private
 connect_to_database(Port, Host, Options) ->