%%
%% %CopyrightBegin%
%% 
%% Copyright Ericsson AB 2006-2016. All Rights Reserved.
%% 
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%% 
%% %CopyrightEnd%
%%
-module(pg_async2).

-define(DRV_CONNECT, 1).
-define(DRV_DISCONNECT, 2).
-define(DRV_SELECT, 3).

-export([connect/1, disconnect/1, select/2]).

connect(ConnectStr) ->
    case erl_ddll:load_driver(".", "pg_async2") of
	ok -> ok;
	{error, already_loaded} -> ok;
	_ -> exit({error, could_not_load_driver})
    end,
    Port = open_port({spawn, ?MODULE}, [binary]),
    port_control(Port, ?DRV_CONNECT, ConnectStr),
    case return_port_data(Port) of
	ok -> {ok, Port};
	Error -> Error
    end.

disconnect(Port) ->
    port_control(Port, ?DRV_DISCONNECT, ""),
    return_port_data(Port).

select(Port, Query) ->
    port_control(Port, ?DRV_SELECT, Query),
    return_port_data(Port).

return_port_data(Port) ->
    receive
	{Port, {data, Data}} ->
	    binary_to_term(Data)
    end.