ui/cocoa: Don't call NSApp sendEvent directly from handleEvent

Currently the handleEvent method will directly call the NSApp
sendEvent method for any events that we want to let OSX deal
with. When we rearrange the event handling code, the way that
we say "let OSX have this event" is going to change. Prepare
for that by refactoring so that handleEvent returns a flag
indicating whether it consumed the event.

Suggested-by: BALATON Zoltan <balaton@eik.bme.hu>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>
Tested-by: Roman Bolshakov <r.bolshakov@yadro.com>
Message-id: 20190225102433.22401-6-peter.maydell@linaro.org
Message-id: 20190214102816.3393-6-peter.maydell@linaro.org

ui/cocoa.m

@@ -129,8 +129,9 @@ bool stretch_video;
 NSTextField *pauseLabel;
 NSArray * supportedImageFileTypes;
 
-// Utility function to run specified code block with iothread lock held
+// Utility functions to run specified code block with iothread lock held
 typedef void (^CodeBlock)(void);
+typedef bool (^BoolCodeBlock)(void);
 
 static void with_iothread_lock(CodeBlock block)
 {
@@ -144,6 +145,21 @@ static void with_iothread_lock(CodeBlock block)
     }
 }
 
+static bool bool_with_iothread_lock(BoolCodeBlock block)
+{
+    bool locked = qemu_mutex_iothread_locked();
+    bool val;
+
+    if (!locked) {
+        qemu_mutex_lock_iothread();
+    }
+    val = block();
+    if (!locked) {
+        qemu_mutex_unlock_iothread();
+    }
+    return val;
+}
+
 // Mac to QKeyCode conversion
 const int mac_to_qkeycode_map[] = {
     [kVK_ANSI_A] = Q_KEY_CODE_A,
@@ -320,8 +336,8 @@ static void handleAnyDeviceErrors(Error * err)
 - (void) ungrabMouse;
 - (void) toggleFullScreen:(id)sender;
 - (void) handleMonitorInput:(NSEvent *)event;
-- (void) handleEvent:(NSEvent *)event;
+- (bool) handleEvent:(NSEvent *)event;
-- (void) handleEventLocked:(NSEvent *)event;
+- (bool) handleEventLocked:(NSEvent *)event;
 - (void) setAbsoluteEnabled:(BOOL)tIsAbsoluteEnabled;
 /* The state surrounding mouse grabbing is potentially confusing.
  * isAbsoluteEnabled tracks qemu_input_is_absolute() [ie "is the emulated
@@ -664,15 +680,16 @@ QemuCocoaView *cocoaView;
     }
 }
 
-- (void) handleEvent:(NSEvent *)event
+- (bool) handleEvent:(NSEvent *)event
 {
-    with_iothread_lock(^{
+    return bool_with_iothread_lock(^{
-        [self handleEventLocked:event];
+        return [self handleEventLocked:event];
     });
 }
 
-- (void) handleEventLocked:(NSEvent *)event
+- (bool) handleEventLocked:(NSEvent *)event
 {
+    /* Return true if we handled the event, false if it should be given to OSX */
     COCOA_DEBUG("QemuCocoaView: handleEvent\n");
     int buttons = 0;
     int keycode = 0;
@@ -743,8 +760,7 @@ QemuCocoaView *cocoaView;
                 if (keycode == Q_KEY_CODE_F) {
                     switched_to_fullscreen = true;
                 }
-                [NSApp sendEvent:event];
+                return false;
-                return;
             }
 
             // default
@@ -759,12 +775,12 @@ QemuCocoaView *cocoaView;
                         // enable graphic console
                         case '1' ... '9':
                             console_select(key - '0' - 1); /* ascii math */
-                            return;
+                            return true;
 
                         // release the mouse grab
                         case 'g':
                             [self ungrabMouse];
-                            return;
+                            return true;
                     }
                 }
             }
@@ -781,7 +797,7 @@ QemuCocoaView *cocoaView;
             // don't pass the guest a spurious key-up if we treated this
             // command-key combo as a host UI action
             if (!isMouseGrabbed && ([event modifierFlags] & NSEventModifierFlagCommand)) {
-                return;
+                return true;
             }
 
             if (qemu_console_is_graphic(NULL)) {
@@ -875,7 +891,7 @@ QemuCocoaView *cocoaView;
             mouse_event = false;
             break;
         default:
-            [NSApp sendEvent:event];
+            return false;
     }
 
     if (mouse_event) {
@@ -911,10 +927,11 @@ QemuCocoaView *cocoaView;
                 qemu_input_queue_rel(dcl->con, INPUT_AXIS_Y, (int)[event deltaY]);
             }
         } else {
-            [NSApp sendEvent:event];
+            return false;
         }
         qemu_input_event_sync();
     }
+    return true;
 }
 
 - (void) grabMouse
@@ -1753,7 +1770,9 @@ static void cocoa_refresh(DisplayChangeListener *dcl)
         event = [NSApp nextEventMatchingMask:NSEventMaskAny untilDate:distantPast
                         inMode: NSDefaultRunLoopMode dequeue:YES];
         if (event != nil) {
-            [cocoaView handleEvent:event];
+            if (![cocoaView handleEvent:event]) {
+                [NSApp sendEvent:event];
+            }
         }
     } while(event != nil);
     [pool release];