check for stuck hotkey prefixe sequences and abort them

feedlist.js

@@ -454,6 +454,8 @@ function feedlist_init() {
 
 		if (!offline_mode) setTimeout("timeout()", 1);
 
+		setTimeout("hotkey_prefix_timeout()", 5*1000);
+
 		if (typeof correctPNG != 'undefined') {
 			correctPNG();
 		}

tt-rss.js

@@ -15,6 +15,7 @@ var number_of_feeds = 0;
 var sanity_check_done = false;
 var _hfd_scrolltop = 0;
 var hotkey_prefix = false;
+var hotkey_prefix_pressed = false;
 var init_params = new Object();
 var ver_offset = 0;
 var hor_offset = 0;
@@ -313,6 +314,25 @@ function viewfeed(feed, subop) {
 	f.viewfeed(feed, subop);
 }
 
+function hotkey_prefix_timeout() {
+	try {
+
+		var date = new Date();
+		var ts = Math.round(date.getTime() / 1000);
+
+		if (hotkey_prefix_pressed && ts - hotkey_prefix_pressed >= 5) {
+			debug("hotkey_prefix seems to be stuck, aborting");
+			hotkey_prefix_pressed = false;
+			hotkey_prefix = false;
+		}
+
+		setTimeout("hotkey_prefix_timeout()", 10);
+
+	} catch  (e) {
+		exception_error("hotkey_prefix_timeout", e);
+	}
+}
+
 function timeout() {
 	if (getInitParam("bw_limit") == "1") return;
 
@@ -1072,8 +1092,12 @@ function hotkey_handler(e) {
 		if ((keycode == 70 || keycode == 67 || keycode == 71) 
 				&& !hotkey_prefix) {
 
+			var date = new Date();
+			var ts = Math.round(date.getTime() / 1000);
+
 			hotkey_prefix = keycode;
-			debug("KP: PREFIX=" + keycode + " CHAR=" + keychar);
+			hotkey_prefix_pressed = ts;
+			debug("KP: PREFIX=" + keycode + " CHAR=" + keychar + " TS=" + ts);
 			return true;
 		}