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-module(mysqlerl_port).
-author('bjc@kublai.com').
-include("mysqlerl_port.hrl").
-behavior(gen_server).
-export([start_link/1]).
-export([init/1, terminate/2, code_change/3,
handle_call/3, handle_cast/2, handle_info/2]).
-record(state, {ref}).
-record(port_closed, {reason}).
start_link(Cmd) ->
gen_server:start_link(?MODULE, [Cmd], []).
init([Cmd]) ->
process_flag(trap_exit, true),
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) ->
catch port_close(State#state.ref),
io:format("DEBUG: mysqlerl_port got terminate: ~p~n", [Reason]),
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
handle_call(#req{request = {Request, Timeout}}, From,
#state{ref = Ref} = State) ->
io:format("DEBUG: Sending request: ~p~n", [Request]),
port_command(Ref, term_to_binary(Request)),
receive
{Ref, {data, Res}} ->
{reply, binary_to_term(Res), State};
{'EXIT', Ref, Reason} ->
gen_server:reply(From, {error, connection_closed}),
{stop, #port_closed{reason = Reason}, State};
Other ->
error_logger:warning_msg("Got unknown query response: ~p~n",
[Other]),
gen_server:reply(From, {error, connection_closed}),
{stop, {unknownreply, Other}, State}
after Timeout ->
gen_server:reply(From, timeout),
{stop, timeout, State}
end.
handle_cast(_Request, State) ->
{noreply, State}.
handle_info({'EXIT', Ref, Reason}, #state{ref = Ref} = State) ->
io:format("DEBUG: Port ~p closed on ~p.~n", [Ref, State]),
{stop, #port_closed{reason = Reason}, State}.
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