Add server side lock key sync heuristic
Based on QEMU's behaviour.
diff --git a/common/rfb/VNCSConnectionST.cxx b/common/rfb/VNCSConnectionST.cxx
index 53dd364..de41e8f 100644
--- a/common/rfb/VNCSConnectionST.cxx
+++ b/common/rfb/VNCSConnectionST.cxx
@@ -34,10 +34,12 @@
#include <rfb/Security.h>
#include <rfb/screenTypes.h>
#include <rfb/fenceTypes.h>
+#include <rfb/ledStates.h>
#include <rfb/ServerCore.h>
#include <rfb/ComparingUpdateTracker.h>
#include <rfb/KeyRemapper.h>
#include <rfb/Encoder.h>
+#define XK_LATIN1
#define XK_MISCELLANY
#define XK_XKB_KEYS
#include <rfb/keysymdef.h>
@@ -560,6 +562,73 @@
}
}
+ // Avoid lock keys if we don't know the server state
+ if ((server->ledState == ledUnknown) &&
+ ((key == XK_Caps_Lock) ||
+ (key == XK_Num_Lock) ||
+ (key == XK_Scroll_Lock))) {
+ vlog.debug("Ignoring lock key (e.g. caps lock)");
+ return;
+ }
+ // Always ignore ScrollLock though as we don't have a heuristic
+ // for that
+ if (key == XK_Scroll_Lock) {
+ vlog.debug("Ignoring lock key (e.g. caps lock)");
+ return;
+ }
+
+ if (down && (server->ledState != ledUnknown)) {
+ // CapsLock synchronisation heuristic
+ // (this assumes standard interaction between CapsLock the Shift
+ // keys and normal characters)
+ if (((key >= XK_A) && (key <= XK_Z)) ||
+ ((key >= XK_a) && (key <= XK_z))) {
+ bool uppercase, shift, lock;
+
+ uppercase = (key >= XK_A) && (key <= XK_Z);
+ shift = pressedKeys.find(XK_Shift_L) != pressedKeys.end() ||
+ pressedKeys.find(XK_Shift_R) != pressedKeys.end();
+ lock = server->ledState & ledCapsLock;
+
+ if (lock == (uppercase == shift)) {
+ vlog.debug("Inserting fake CapsLock to get in sync with client");
+ server->desktop->keyEvent(XK_Caps_Lock, true);
+ server->desktop->keyEvent(XK_Caps_Lock, false);
+ }
+ }
+
+ // NumLock synchronisation heuristic
+ // (this is more cautious because of the differences between Unix,
+ // Windows and macOS)
+ if (((key >= XK_KP_Home) && (key <= XK_KP_Delete)) ||
+ ((key >= XK_KP_0) && (key <= XK_KP_9)) ||
+ (key == XK_KP_Separator) || (key == XK_KP_Decimal)) {
+ bool number, shift, lock;
+
+ number = ((key >= XK_KP_0) && (key <= XK_KP_9)) ||
+ (key == XK_KP_Separator) || (key == XK_KP_Decimal);
+ shift = pressedKeys.find(XK_Shift_L) != pressedKeys.end() ||
+ pressedKeys.find(XK_Shift_R) != pressedKeys.end();
+ lock = server->ledState & ledNumLock;
+
+ if (shift) {
+ // We don't know the appropriate NumLock state for when Shift
+ // is pressed as it could be one of:
+ //
+ // a) A Unix client where Shift negates NumLock
+ //
+ // b) A Windows client where Shift only cancels NumLock
+ //
+ // c) A macOS client where Shift doesn't have any effect
+ //
+ } else if (lock == (number == shift)) {
+ vlog.debug("Inserting fake NumLock to get in sync with client");
+ server->desktop->keyEvent(XK_Num_Lock, true);
+ server->desktop->keyEvent(XK_Num_Lock, false);
+ }
+ }
+ }
+
// Turn ISO_Left_Tab into shifted Tab.
VNCSConnectionSTShiftPresser shiftPresser(server->desktop);
if (key == XK_ISO_Left_Tab) {