Added async-input.

The input is now done by ncurses itself. The driver starts a thread that will do getch() continuously and send a message back to Erlang when it has a character. meanwhile if a process asks for a char (cecho:getch()) it will block by first sending a message to the cecho_srv process and "register" itself as waiting and then as soon as a key input is read from the driver it will be sent to it.

If a message is received from the port and no process is waiting for the character then the message will be discarded.
If a process tries to do cecho:getch() at the same time as another one is already blocking the process that called cecho:getch() last will be killed.

If special characters need to be captured then cecho:keypad/2 must be used to enable keypad mode.

NOTE: erl must be started with +A <N> where N is a number (probably above 40, try e.g. 50 or above) AND the flag -noinput must be given to stop the erlang shell from reading input (and thus competing) with cecho. To test the new feature run cecho_example:input() as follows:

$> pwd
/home/mazen/dev/repos/cecho
$> erl -pa ../cecho/ebin/ -noinput -eval 'cecho_example:input(),halt().' +A 50
$>

Use 'q' to quit.

c_src/cecho.c

@@ -58,6 +58,7 @@ void integer(ei_x_buff *eixb, int integer);
 void string(ei_x_buff *eixb, const char *str);
 void encode_ok_reply(state *st, int code);
 int findfreewindowslot(state *st);
+void loop_getch(void *arg);
 
 void do_endwin(state *st);
 void do_initscr(state *st);
@@ -116,6 +117,11 @@ static void stop(ErlDrvData drvstate) {
   driver_free(drvstate);
 }
 
+static void init_getch_loop(ErlDrvData drvstate, char *buf, int buflen) {
+  state *st = (state *)drvstate;
+  driver_async(st->drv_port, NULL, loop_getch, (void *)st, NULL);
+}
+
 static int ctrl(ErlDrvData drvstate, unsigned int command, char *args, 
 		int argslen, char **rbuf, int rbuflen) {
   state *st = (state *)drvstate;
@@ -549,14 +555,26 @@ int findfreewindowslot(state *st) {
   return -1;
 }
 
+void loop_getch(void *arg) {
+  state *st = (state *)arg;
+  ei_x_buff eixb;
+  int keycode;
+  while(1) {
+    ei_x_new_with_version(&eixb);
+    keycode = getch();
+    integer(&eixb, keycode);
+    driver_output(st->drv_port, eixb.buff, eixb.index);
+  }
+}
+
 // =============================================================================
 // Erlang driver_entry Specification
 // ===========================================================================
 ErlDrvEntry driver_entry = {
   NULL,
   start,
   stop,
-  NULL,
+  init_getch_loop,
   NULL,
   NULL,
   "cecho",

src/cecho.erl

@@ -41,7 +41,7 @@
 	 scrollok/2, mvaddch/3, mvaddstr/3, newwin/4, delwin/1, wmove/3,
 	 waddstr/2, waddch/2, mvwaddstr/4, mvwaddch/4, wrefresh/1, hline/2,
 	 whline/3, vline/2, wvline/3, border/8, wborder/9, box/3, getyx/1,
-	 getmaxyx/1, attron/2, attroff/2, keypad/2]).
+	 getmaxyx/1, attron/2, attroff/2, keypad/2, getch/0]).
 
 %% =============================================================================
 %% Application API
@@ -191,6 +191,9 @@ box(Window, Vert, Horz) when is_integer(Window) andalso is_integer(Vert) andalso
 keypad(Window, BFlag) when is_integer(Window) andalso is_boolean(BFlag) ->
     call(?KEYPAD, {Window, BFlag}).
 
+getch() ->
+    cecho_srv:getch().
+
 %% =============================================================================
 %% Behaviour Callbacks
 %% =============================================================================

src/cecho_example.erl

@@ -174,13 +174,14 @@ input() ->
     ok = cecho:cbreak(),
     ok = cecho:noecho(),
     ok = cecho:curs_set(?ceCURS_INVISIBLE),
+    ok = cecho:keypad(?ceSTDSCR, true),
     spawn_link(?MODULE, input_counter, [0]),
     cecho:mvaddstr(9, 10, "Enter:    "),
     cecho:refresh(),
     input_reader().
 
 input_reader() ->
-    [P] = io:get_chars('',1),
+    P = cecho:getch(),
     case P of
 	113 ->
 	    application:stop(cecho);

src/cecho_srv.erl

@@ -35,10 +35,10 @@
 	 code_change/3]).
 
 %% Module API
--export([start_link/0, call/2 ]).
+-export([start_link/0, call/2, getch/0]).
 
 %% Records
--record(state, { port }).
+-record(state, { port, getpid }).
 
 %% =============================================================================
 %% Module API
@@ -49,17 +49,25 @@ start_link() ->
 call(Cmd, Args) ->
     gen_server:call(?MODULE, {call, Cmd, Args}, infinity).
 
+getch() ->
+    ?MODULE ! {getch, self()},
+    receive 
+	{ch, Chr} ->
+	    Chr
+    end.
+
 %% =============================================================================
 %% Behaviour Callbacks
 %% =============================================================================
 init(no_args) ->
     process_flag(trap_exit, true),
     case erl_ddll:load(code:priv_dir(cecho)++"/lib","cecho") of
 	ok ->
-	    Port = erlang:open_port({spawn, "cecho"}, []),
+	    Port = erlang:open_port({spawn, "cecho"}, [binary]),
 	    ok = do_call(Port, ?INITSCR),
 	    ok = do_call(Port, ?ERASE),
 	    ok = do_call(Port, ?REFRESH),
+	    erlang:port_command(Port, <<>>),
 	    {ok, #state{ port = Port }};
 	{error, ErrorCode} ->
 	    exit({driver_error, erl_ddll:format_error(ErrorCode)})
@@ -75,12 +83,20 @@ terminate(_Reason, State) ->
     erlang:port_close(State#state.port),
     erl_ddll:unload("cecho").
 
-%% @hidden
-handle_cast(_, State) ->
-    {noreply, State}.
+handle_info({getch, From}, #state{ getpid = undefined } = State) ->
+    {noreply, State#state{ getpid = From }};
+handle_info({getch, From}, State) ->
+    exit(From, kill),
+    {noreply, State};
+handle_info({_Port, {data, _Binary}}, #state{ getpid = undefined } = State) ->
+    {noreply, State};
+handle_info({_Port, {data, Binary}}, State) ->
+    Ch = binary_to_term(Binary),
+    State#state.getpid ! {ch, Ch},
+    {noreply, State#state{ getpid = undefined }}.
 
 %% @hidden
-handle_info(_, State) ->
+handle_cast(_, State) ->
     {noreply, State}.
 
 %% @hidden