%%

%% %CopyrightBegin%

%% 
%% Copyright Ericsson AB 2006-2009. All Rights Reserved.
%% 
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%% 
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%% 
%% %CopyrightEnd%

%%

-module(pg_async).



-define(DRV_CONNECT, $C).

-define(DRV_DISCONNECT, $D).

-define(DRV_SELECT, $S).



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



connect(ConnectStr) ->

    case erl_ddll:load_driver(".", "pg_async") of

	ok -> ok;

	{error, already_loaded} -> ok;

	E -> exit(E)

    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, ""),

    R = return_port_data(Port),

    port_close(Port),

    R.



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.