Reworked XNextEventWithTimeout.

New way of signaling autorepeats by the X11 servers broke Superkb.
Before we had a lot of KeyPresses and a single KeyRelease. Now we
have a lot of KeyPress/KeyRelease combinations. We must peek into
the next X event to see if it matches a KeyPress. If so, we must
ignore both.

We had to invert the logic for QLength() == 0 management and enclose
everything in a loop to continue if the events were swallowed.

This is to only emulate the old way before the rest of the codebase.

See: https://stackoverflow.com/questions/2100654

Signed-off-by: Octavio Alvarez <alvarezp@alvarezp.ods.org>

superkb.c

@@ -99,29 +99,46 @@ XNextEventWithTimeout(Display * display, XEvent * event_return,
 
 	XFlush(display);
 
-	if (QLength(display) > 0) {
-		XNextEvent(display, event_return);
-		return 1;
-	}
+	while (1) {
+		if (QLength(display) <= 0) {
 
-	FD_ZERO(&fd);
-	FD_SET(XConnectionNumber(display), &fd);
+			FD_ZERO(&fd);
+			FD_SET(XConnectionNumber(display), &fd);
 
-	do {
-		r = select(FD_SETSIZE, &fd, NULL, NULL, to);
-	} while(r == -1 && errno == EINTR);
+			do {
+				r = select(FD_SETSIZE, &fd, NULL, NULL, to);
+			} while(r == -1 && errno == EINTR);
 
-	if (r == -1) {
-		/* Some error other than EINTR. */
-		return -errno;
-	}
+			if (r == -1) {
+				/* Some error other than EINTR. */
+				return -errno;
+			}
 
-	if (r == 0) {
-		/* Timeout */
-		return r;
-	}
+			if (r == 0) {
+				/* Timeout */
+				return r;
+			}
 
-	XNextEvent(display, event_return);
+		}
+
+		XNextEvent(display, event_return);
+
+		/* Swallow next event if this is a key-repeating event */
+		if (event_return->type == KeyRelease && XEventsQueued(display, QueuedAfterReading))
+		{
+			XEvent nev;
+			XPeekEvent(display, &nev);
+
+			if (nev.type == KeyPress && nev.xkey.time == event_return->xkey.time &&
+				nev.xkey.keycode == event_return->xkey.keycode)
+			{
+				/* Key wasn’t actually released. Swallow this event and the next one. */
+				XNextEvent(display, event_return);
+				continue;
+			}
+		}
+		break;
+	}
 	return 1;
 }