[Qemu-devel] [PATCH] ui/cocoa.m: prevent stuck command key when going into full screen mode

[John Arbuckle <programmingkidx@gmail.com>]

When the user pushes Command-F in QEMU while the mouse is ungrabbed, QEMU
goes into full screen mode. When the user finally releases the command key,
it is sent to the guest as an event. The makes the guest operating system
think the command key is down when it is really up. To prevent this situation
from happening, we simply drop the first command key event after the user has
gone into full screen mode using Command-F.

Signed-off-by: John Arbuckle <programmingkidx@gmail.com>
---
 ui/cocoa.m | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/ui/cocoa.m b/ui/cocoa.m
index 2991ed4..024aba2 100644
--- a/ui/cocoa.m
+++ b/ui/cocoa.m
@@ -287,6 +287,7 @@ static void handleAnyDeviceErrors(Error * err)
     BOOL isFullscreen;
     BOOL isAbsoluteEnabled;
     BOOL isMouseDeassociated;
+    BOOL prevent_stuck_command_key;
 }
 - (void) switchSurface:(DisplaySurface *)surface;
 - (void) grabMouse;
@@ -330,7 +331,7 @@ QemuCocoaView *cocoaView;
         screen.bitsPerPixel = 32;
         screen.width = frameRect.size.width;
         screen.height = frameRect.size.height;
-
+        prevent_stuck_command_key = NO;
     }
     return self;
 }
@@ -552,6 +553,14 @@ QemuCocoaView *cocoaView;
 }
 
 - (void) toggleModifier: (int)keycode {
+
+    /* Prevents the command key from being sent to the guest */
+    if ((keycode == Q_KEY_CODE_META_L || keycode == Q_KEY_CODE_META_R) &&
+        prevent_stuck_command_key == YES) {
+        prevent_stuck_command_key = NO;
+        return;
+    }
+
     // Toggle the stored state.
     modifiers_state[keycode] = !modifiers_state[keycode];
     // Send a keyup or keydown depending on the state.
@@ -691,6 +700,13 @@ QemuCocoaView *cocoaView;
 
             // forward command key combos to the host UI unless the mouse is grabbed
             if (!isMouseGrabbed && ([event modifierFlags] & NSEventModifierFlagCommand)) {
+                /*
+                 * Prevent the command key from being stuck down in the guest
+                 * when using Command-F for full screen mode
+                 */
+                if (keycode == Q_KEY_CODE_F) {
+                    prevent_stuck_command_key = YES;
+                }
                 [NSApp sendEvent:event];
                 return;
             }
-- 
2.7.2