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-module(mysqlerl_connection).
-author('bjc@kublai.com').
-behavior(gen_server).
-export([start_link/6, stop/1, sql_query/3]).
-export([init/1, terminate/2, code_change/3,
handle_call/3, handle_cast/2, handle_info/2]).
-define(QUERY_MSG, 0).
-define(COMMIT_MSG, 1).
-define(ROLLBACK_MSG, 2).
-define(EXTENDED_MSG, 255).
-record(state, {ref}).
-record(port_closed, {reason}).
-record(sql_query, {q}).
start_link(Host, Port, Database, User, Password, Options) ->
gen_server:start_link(?MODULE, [Host, Port, Database,
User, Password, Options], []).
stop(Pid) ->
gen_server:cast(Pid, stop).
sql_query(Pid, Query, Timeout) ->
gen_server:call(Pid, #sql_query{q = Query}, Timeout).
init([Host, Port, Database, User, Password, Options]) ->
process_flag(trap_exit, true),
Cmd = lists:flatten(io_lib:format("~s ~s ~w ~s ~s ~s ~s",
[helper(), Host, Port, Database,
User, Password, Options])),
Ref = open_port({spawn, Cmd}, [{packet, 4}, binary]),
{ok, #state{ref = Ref}}.
terminate(#port_closed{reason = Reason}, #state{ref = Ref}) ->
io:format("DEBUG: mysqlerl connection ~p shutting down (~p).~n",
[Ref, Reason]),
ok;
terminate(Reason, State) ->
port_close(State#state.ref),
io:format("DEBUG: got terminate: ~p~n", [Reason]),
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
handle_call(#sql_query{q = Query}, _From, State) ->
{reply, handle_query(State#state.ref, Query), State};
handle_call(Request, From, State) ->
io:format("DEBUG: got unknown call from ~p: ~p~n", [From, Request]),
{noreply, State}.
handle_cast(stop, State) ->
{stop, normal, State}.
handle_info({'EXIT', _Ref, Reason}, State) ->
{stop, #port_closed{reason = Reason}, State};
handle_info(Info, State) ->
io:format("DEBUG: got unknown info: ~p~n", [Info]),
{noreply, State}.
helper() ->
case code:priv_dir(mysqlerl) of
PrivDir when is_list(PrivDir) -> ok;
{error, bad_name} -> PrivDir = filename:join(["..", "priv"])
end,
filename:join([PrivDir, "mysqlerl"]).
handle_query(Ref, Query) ->
io:format("DEBUG: got query: ~p~n", [Query]),
make_request(Ref, {sql_query, Query}).
make_request(Ref, Req) ->
port_command(Ref, term_to_binary(Req)),
receive
{Ref, {data, Res}} -> {ok, Res};
Other ->
error_logger:warning_msg("Got unknown query response: ~p~n",
[Other]),
exit({badreply, Other})
end.
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