Fix Cmd+F4 disc cycling shortcut

Boxer/BXSession+BXUIControls.h

@@ -159,6 +159,9 @@ typedef NS_ENUM(NSInteger, BXPlaybackMode) {
 - (IBAction) mountNextDrivesInQueues: (id)sender;
 - (IBAction) mountPreviousDrivesInQueues: (id)sender;
 
+/// Cycle all mounted drives to their next queued images. Triggered by Cmd+F4 keyboard shortcut.
+- (IBAction) cycleMountedDiscsForward: (id)sender;
+
 /// Whether we have any drive queues that can be cycled. Used for UI bindings.
 - (BOOL) canCycleDrivesInQueues;
 

Boxer/BXSession+BXUIControls.m

@@ -1087,6 +1087,36 @@ - (IBAction) mountPreviousDrivesInQueues: (id)sender
     [self _mountQueuedSiblingsAtOffset: -1];
 }
 
+- (IBAction) cycleMountedDiscsForward: (id)sender
+{
+    //Cycle through each mounted drive's queued images, showing bezel notifications for each change.
+    //This is triggered by Cmd+F4 in the keyboard input handler.
+    for (BXDrive *currentDrive in self.mountedDrives)
+    {
+        BXDrive *siblingDrive = [self siblingOfQueuedDrive: currentDrive atOffset: 1];
+        if (siblingDrive && ![siblingDrive isEqual: currentDrive])
+        {
+            NSError *mountError = nil;
+            BXDrive *mountedDrive = [self mountDrive: siblingDrive
+                                            ifExists: BXDriveReplace
+                                             options: BXDefaultDriveMountOptions
+                                               error: &mountError];
+
+            if (!mountedDrive && mountError)
+            {
+                [self presentError: mountError
+                    modalForWindow: self.windowForDriveSheet
+                          delegate: nil
+                didPresentSelector: NULL
+                       contextInfo: NULL];
+
+                //Don't continue mounting if we encounter a problem
+                break;
+            }
+        }
+    }
+}
+
 + (NSSet *) keyPathsForValuesAffectingCanCycleDrivesInQueues
 {
     return [NSSet setWithObject: @"drives"];

Boxer/DOS window/BXInputController+BXKeyboardInput.m

@@ -68,6 +68,14 @@ - (void) _syncKeyboardLayout
 
 - (void) keyDown: (NSEvent *)theEvent
 {
+	//Special handling for Cmd+F4 to cycle through mounted disc images
+	if ((theEvent.modifierFlags & NSEventModifierFlagCommand) == NSEventModifierFlagCommand &&
+		theEvent.keyCode == kVK_F4)
+	{
+		[self cycleMountedDiscsForward: self];
+		return;
+	}
+
 	//If the keypress was command-modified, don't pass it on to the emulator as it indicates
 	//a failed key equivalent.
 	//(This is consistent with how other OS X apps with textinput handle Cmd-keypresses.)
@@ -230,6 +238,10 @@ - (IBAction) sendForwardSlash:  (id)sender { [self.representedObject.emulator ha
 - (IBAction) sendColon:         (id)sender { [self.representedObject.emulator handlePastedString: @":" asCommand: NO]; }
 - (IBAction) sendDash:          (id)sender { [self.representedObject.emulator handlePastedString: @"-" asCommand: NO]; }
 
+- (IBAction) cycleMountedDiscsForward: (id)sender
+{
+	[self.representedObject cycleMountedDiscsForward: sender];
+}
 
 - (void) type: (NSString *)message
 {