%%%-------------------------------------------------------------------
%%% @author Matt Williamson <dawsdesign@gmail.com>
%%% @copyright (C) 2009, Matt Williamson
%%% @doc
%%%
%%% @end
%%% Created : 18 May 2009 by Matt Williamson <dawsdesign@gmail.com>
%%%-------------------------------------------------------------------
-module(bdb_store).
-behaviour(gen_server).
%% API
-export([start_link/0]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-define(SERVER, ?MODULE).
-define('DRIVER_NAME', 'bdb_drv').
-record(state, {port}).
%%%===================================================================
%%% API
%%%===================================================================
%%--------------------------------------------------------------------
%% @doc
%% Starts the server
%%
%% @spec start_link() -> {ok, Pid} | ignore | {error, Error}
%% @end
%%--------------------------------------------------------------------
start_link() ->
gen_server:start_link({local, ?SERVER}, ?MODULE, [], []).
%%%===================================================================
%%% gen_server callbacks
%%%===================================================================
%%--------------------------------------------------------------------
%% @private
%% @doc
%% Initiates the server
%%
%% @spec init(Args) -> {ok, State} |
%% {ok, State, Timeout} |
%% ignore |
%% {stop, Reason}
%% @end
%%--------------------------------------------------------------------
init([]) ->
SearchDir = filename:join([filename:dirname(code:which(?MODULE)), "..", "priv"]),
case erl_ddll:load(SearchDir, atom_to_list(?DRIVER_NAME)) of
ok ->
{ok, #state{port=open_port({spawn, ?DRIVER_NAME}, [binary])}};
Error ->
Error
end.
%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling call messages
%%
%% @spec handle_call(Request, From, State) ->
%% {reply, Reply, State} |
%% {reply, Reply, State, Timeout} |
%% {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, Reply, State} |
%% {stop, Reason, State}
%% @end
%%-------------------------------------------------------------------
handle_call({put, Key, Value}, _From, State)
when is_binary(Key) and is_binary(Value) ->
Message = <<1, Key/binary, Value/binary>>,
Reply = send_command(State#state.port, Message),
{reply, Reply, State};
handle_call({get, Key}, _From, State)
when is_binary(Key) ->
Message = <<2, Key/binary>>,
Reply = send_command(State#state.port, Message),
{reply, Reply, State};
handle_call({delete, Key}, _From, State)
when is_binary(Key) ->
Message = <<3, Key/binary>>,
Reply = send_command(State#state.port, Message),
{reply, Reply, State};
handle_call(_Request, _From, State) ->
Reply = {error, unkown_call},
{reply, Reply, State}.
%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling cast messages
%%
%% @spec handle_cast(Msg, State) -> {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_cast(_Msg, State) ->
{noreply, State}.
%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling all non call/cast messages
%%
%% @spec handle_info(Info, State) -> {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_info(_Info, State) ->
{noreply, State}.
%%--------------------------------------------------------------------
%% @private
%% @doc
%% This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any
%% necessary cleaning up. When it returns, the gen_server terminates
%% with Reason. The return value is ignored.
%%
%% @spec terminate(Reason, State) -> void()
%% @end
%%--------------------------------------------------------------------
terminate(_Reason, State) ->
port_close(State#state.port),
ok.
%%--------------------------------------------------------------------
%% @private
%% @doc
%% Convert process state when code is changed
%%
%% @spec code_change(OldVsn, State, Extra) -> {ok, NewState}
%% @end
%%--------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%%%===================================================================
%%% Internal functions
%%%===================================================================
send_command(Port, Command) ->
port_command(Port, Command),
receive
Data ->
Data
after 100 ->
io:format("Received nothing!~n"),
{error, timeout}
end.
