Optionally distinguish between timeout and NUL inkey() result

Some terminals can send NUL (ASCII 0), e.g. hitting Ctrl-Space in Apple iTerm. Allow users of inkey() (in C++ or JS) to optionally detect the difference by specifying the K_NUL mode flag. In JS, console.inkey() will return null upon timeout (rather than "") when the K_NUL mode flag is used and return an empty string ("") upon receipt of NUL (ASCII 0).

The default is the previous behavior where a timeout and the receipt of a NUL character appear the same to the caller of inkey().

src/sbbs3/inkey.cpp

-/* Synchronet single key input function (no wait) */
-
-/* $Id: inkey.cpp,v 1.80 2020/08/04 04:56:37 rswindell Exp $ */
+/* Synchronet single key input function */
 
 /****************************************************************************
  * @format.tab-size 4		(Plain Text/Source Code File Header)			*
@@ -15,21 +13,9 @@
  * See the GNU General Public License for more details: gpl.txt or			*
  * http://www.fsf.org/copyleft/gpl.html										*
  *																			*
- * Anonymous FTP access to the most recent released source is available at	*
- * ftp://vert.synchro.net, ftp://cvs.synchro.net and ftp://ftp.synchro.net	*
- *																			*
- * Anonymous CVS access to the development source and modification history	*
- * is available at cvs.synchro.net:/cvsroot/sbbs, example:					*
- * cvs -d :pserver:anonymous@cvs.synchro.net:/cvsroot/sbbs login			*
- *     (just hit return, no password is necessary)							*
- * cvs -d :pserver:anonymous@cvs.synchro.net:/cvsroot/sbbs checkout src		*
- *																			*
  * For Synchronet coding style and modification guidelines, see				*
  * http://www.synchro.net/source.html										*
  *																			*
- * You are encouraged to submit any modifications (preferably in Unix diff	*
- * format) via e-mail to mods@synchro.net									*
- *																			*
  * Note: If this box doesn't appear square, then you need to fix your tabs.	*
  ****************************************************************************/
 
@@ -95,18 +81,20 @@ int kbincom(sbbs_t* sbbs, unsigned long timeout)
 
 /****************************************************************************/
 /* Returns character if a key has been hit remotely and responds			*/
-/* Called from functions getkey, msgabort and main_sec						*/
+/* May return NOINP on timeout instead of '\0' when K_NUL mode is used.		*/
 /****************************************************************************/
-char sbbs_t::inkey(long mode, unsigned long timeout)
+int sbbs_t::inkey(long mode, unsigned long timeout)
 {
-	uchar	ch=0;
+	int	ch=0;
 
 	ch=kbincom(this,timeout); 
 
-	if(ch==0) {
+	if(ch == NOINP) {
 		if(sys_status&SS_SYSPAGE) 
 			sbbs_beep(sbbs_random(800),100);
-		return(0);
+		if(mode & K_NUL)	// distinguish between timeout and '\0'
+			return NOINP;
+		return 0;
 	}
 
 	if(cfg.node_misc&NM_7BITONLY

src/sbbs3/js_console.cpp

-/* js_console.cpp */
-
 /* Synchronet JavaScript "Console" Object */
 
-/* $Id: js_console.cpp,v 1.154 2020/05/24 08:16:52 rswindell Exp $ */
-
 /****************************************************************************
  * @format.tab-size 4		(Plain Text/Source Code File Header)			*
  * @format.use-tabs true	(see http://www.synchro.net/ptsc_hdr.html)		*
@@ -17,21 +13,9 @@
  * See the GNU General Public License for more details: gpl.txt or			*
  * http://www.fsf.org/copyleft/gpl.html										*
  *																			*
- * Anonymous FTP access to the most recent released source is available at	*
- * ftp://vert.synchro.net, ftp://cvs.synchro.net and ftp://ftp.synchro.net	*
- *																			*
- * Anonymous CVS access to the development source and modification history	*
- * is available at cvs.synchro.net:/cvsroot/sbbs, example:					*
- * cvs -d :pserver:anonymous@cvs.synchro.net:/cvsroot/sbbs login			*
- *     (just hit return, no password is necessary)							*
- * cvs -d :pserver:anonymous@cvs.synchro.net:/cvsroot/sbbs checkout src		*
- *																			*
  * For Synchronet coding style and modification guidelines, see				*
  * http://www.synchro.net/source.html										*
  *																			*
- * You are encouraged to submit any modifications (preferably in Unix diff	*
- * format) via e-mail to mods@synchro.net									*
- *																			*
  * Note: If this box doesn't appear square, then you need to fix your tabs.	*
  ****************************************************************************/
 
@@ -458,6 +442,7 @@ js_inkey(JSContext *cx, uintN argc, jsval *arglist)
 {
 	jsval *argv=JS_ARGV(cx, arglist);
 	char		key[2];
+	int			ch;
 	int32		mode=0;
 	int32		timeout=0;
 	sbbs_t*		sbbs;
@@ -467,7 +452,7 @@ js_inkey(JSContext *cx, uintN argc, jsval *arglist)
 	if((sbbs=(sbbs_t*)js_GetClassPrivate(cx, JS_THIS_OBJECT(cx, arglist), &js_console_class))==NULL)
 		return(JS_FALSE);
 
-	JS_SET_RVAL(cx, arglist, JSVAL_VOID);
+	JS_SET_RVAL(cx, arglist, JSVAL_NULL);
 
 	if(argc) {
 		if(!JS_ValueToInt32(cx,argv[0],&mode))
@@ -478,14 +463,15 @@ js_inkey(JSContext *cx, uintN argc, jsval *arglist)
 			return JS_FALSE;
 	}
 	rc=JS_SUSPENDREQUEST(cx);
-	key[0]=sbbs->inkey(mode,timeout);
+	ch = sbbs->inkey(mode,timeout);
+	if(ch != NOINP) {
+		key[0]=ch;
+		key[1]=0;
+		if((js_str = JS_NewStringCopyZ(cx, key))==NULL)
+			return(JS_FALSE);
+		JS_SET_RVAL(cx, arglist, STRING_TO_JSVAL(js_str));
+	}
 	JS_RESUMEREQUEST(cx, rc);
-	key[1]=0;
-
-	if((js_str = JS_NewStringCopyZ(cx, key))==NULL)
-		return(JS_FALSE);
-
-	JS_SET_RVAL(cx, arglist, STRING_TO_JSVAL(js_str));
     return(JS_TRUE);
 }
 
@@ -2118,7 +2104,7 @@ js_term_updated(JSContext *cx, uintN argc, jsval *arglist)
 static jsSyncMethodSpec js_console_functions[] = {
 	{"inkey",			js_inkey,			0, JSTYPE_STRING,	JSDOCSTR("[mode=<tt>K_NONE</tt>] [,timeout=<tt>0</tt>]")
 	,JSDOCSTR("get a single key with optional <i>timeout</i> in milliseconds (defaults to 0, for no wait).<br>"
-		"Returns an empty string if there is no input (e.g. timeout occurs).<br>"
+		"Returns an empty string (or <tt>null</tt> when the <tt>K_NUL</tt> mode flag is used) if there is no input (e.g. timeout occurs).<br>"
 		"See <tt>K_*</tt> in <tt>sbbsdefs.js</tt> for <i>mode</i> flags.")
 	,311
 	},

src/sbbs3/sbbs.h

@@ -824,7 +824,7 @@ public:
 	void	mnemonics(const char *str);
 
 	/* inkey.cpp */
-	char	inkey(long mode, unsigned long timeout=0);
+	int		inkey(long mode, unsigned long timeout=0);
 	char	handle_ctrlkey(char ch, long mode=0);
 
 									// Terminal mouse reporting mode (mouse_mode)

src/sbbs3/sbbsdefs.h

@@ -760,6 +760,7 @@ typedef enum {						/* Values for xtrn_t.event				*/
 #define K_ANSI_CPR	(1L<<22)	/* Expect ANSI Cursor Position Report		*/
 #define K_TRIM		(1L<<23)	/* Trimmed white-space						*/
 #define K_CTRLKEYS	(1L<<24)	/* No control-key handling/eating in inkey()*/
+#define K_NUL		(1L<<25)	/* Return NOINP on timeout instead of '\0'	*/
 
 								/* Bits in 'mode' for putmsg and printfile  */
 #define P_NONE		0			/* No mode flags							*/