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%%%-------------------------------------------------------------------
%% @doc Serves the cached menu over a Unix domain socket.
%%
%% Connecting to the socket *is* the request: each accepted connection
%% is handed the current `er_xdg_pipe_menu_cache:get_menu/0' binary and
%% closed. There is no request payload to parse.
%% @end
%%%-------------------------------------------------------------------
-module(er_xdg_pipe_menu_socket).
-export([start_link/0, socket_path/0]).
-export([init/1]).
-spec start_link() -> {ok, pid()}.
start_link() ->
proc_lib:start_link(?MODULE, init, [self()]).
-spec socket_path() -> file:filename_all().
socket_path() ->
case application:get_env(er_xdg_pipe_menu, socket_path) of
{ok, Path} -> Path;
undefined -> default_socket_path()
end.
default_socket_path() ->
case env("XDG_RUNTIME_DIR") of
undefined -> filename:join("/tmp", "er_xdg_pipe_menu-" ++ os:getenv("USER", "unknown") ++ ".sock");
Dir -> filename:join(Dir, "er_xdg_pipe_menu.sock")
end.
env(Name) ->
case os:getenv(Name) of
false -> undefined;
"" -> undefined;
Value -> Value
end.
init(Parent) ->
Path = socket_path(),
%% Clean up a stale socket file left behind by a previous run that
%% didn't shut down cleanly; gen_tcp:listen fails with eaddrinuse
%% otherwise.
_ = file:delete(Path),
{ok, Listen} = gen_tcp:listen(0, [
{ifaddr, {local, Path}},
binary,
{active, false},
{packet, raw},
{reuseaddr, true}
]),
proc_lib:init_ack(Parent, {ok, self()}),
accept_loop(Listen).
accept_loop(Listen) ->
case gen_tcp:accept(Listen) of
{ok, Socket} ->
spawn(fun() -> serve(Socket) end),
accept_loop(Listen);
{error, Reason} ->
exit(Reason)
end.
serve(Socket) ->
gen_tcp:send(Socket, er_xdg_pipe_menu_cache:get_menu()),
gen_tcp:close(Socket).
|
