Firefox Key Equivalent Fixer

main.m

#import <Foundation/Foundation.h>
#import <AppKit/AppKit.h>
#import "ZKSwizzle.h"




@interface myNSApplication : NSApplication
@end


@implementation myNSApplication

- (void)sendEvent:(NSEvent *)event {
	// Firefox does not handle user-defined key equivalents properly
	// https://bugzilla.mozilla.org/show_bug.cgi?id=1333781
	
	// Check if the event is a key down event with a modifier key. (Otherwise, it can't be a keyboard shortcut.)
	if (
		[event type] == NSKeyDown &&
		[event modifierFlags] & (NSCommandKeyMask | NSAlternateKeyMask | NSControlKeyMask)
		//We don't check NSShiftKeyMask because shortcuts aren't allowed to use Shift as the only modifier key.
	) {		
		// Query user-defined key equivalents
		NSDictionary *userKeyEquivalents = [[NSUserDefaults standardUserDefaults] objectForKey:@"NSUserKeyEquivalents"];

		if (userKeyEquivalents) {
			// Check if the event matches any user-defined key equivalents
			for (NSString *menuItemTitle in userKeyEquivalents) {
				NSString *shortcut = userKeyEquivalents[menuItemTitle];
				if ([self event:event matchesShortcut:shortcut]) {
					[self performKeyEquivalent:event];
					[self performActionForItemWithTitle:menuItemTitle inMenu:[NSApp mainMenu]];
					return;
				}
			}
		}
	}
	// Pass event to Firefox to handle normally.
	ZKOrig(void, event);
}



- (BOOL)event:(NSEvent *)event matchesShortcut:(NSString *)shortcut {
	// Convert the shortcut string to a key equivalent and modifier mask
	NSString *characterKey = [shortcut substringFromIndex:[shortcut length] - 1];
	NSString *modifierString = [shortcut substringToIndex:[shortcut length] - 1];
	NSUInteger modifierMask = 0;
	for (int i = 0; i < [modifierString length]; i++) {
		switch ([modifierString characterAtIndex:i]) {
			case '@':
				modifierMask |= NSCommandKeyMask;
				break;
			case '~':
				modifierMask |= NSAlternateKeyMask;
				break;
			case '^':
				modifierMask |= NSControlKeyMask;
				break;
			case '$':
				modifierMask |= NSShiftKeyMask;
				break;
		}
	}
	// Compare with the event
	return (
		[[[event charactersIgnoringModifiers] lowercaseString] isEqualToString:characterKey] &&
		([event modifierFlags] & NSDeviceIndependentModifierFlagsMask) == modifierMask
	);
}

- (void)performActionForItemWithTitle:(NSString *)title inMenu:(NSMenu *)menu {	
	for (NSMenuItem *menuItem in [menu itemArray]) {
		if ([menuItem hasSubmenu]) {
			[self performActionForItemWithTitle:title inMenu:[menuItem submenu]];
		} else {
			
			//Ensure three periods ("...") matches the elipses character ("…").
			title = [title stringByReplacingOccurrencesOfString:@"..." withString:@"…"];
			NSString *menuItemTitle = [[menuItem title] stringByReplacingOccurrencesOfString:@"..." withString:@"…"];
			
			if ([menuItemTitle isEqualToString:title]) {
				[[menuItem menu] update]; //highlight menu
				[[menuItem menu] performActionForItemAtIndex:[[menuItem menu] indexOfItem:menuItem]];
				return;
			}
		}
	}
}

@end




@interface myNSWindow : NSWindow
@end


@implementation myNSWindow

- (BOOL)makeFirstResponder:(NSResponder *)responder {
				
	//Initialize menus to ensure:
	//1. Every item can be triggerred by its key equivalents
	//2. Every item can appear in the search results of the `Help` search box.
	[self initializeSubmenusOf: [NSApp mainMenu]];
	
	//We should also listen for menu changes. Unfortunately, the below code will crash Firefox.
	//Todo: figure out how to do this properly!
	/*[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(initializeSubmenusOf:) name:@"NSMenuDidAddItemNotification" object:[NSApp mainMenu]];
	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(initializeSubmenusOf:) name:@"NSMenuDidRemoveItemNotification" object:[NSApp mainMenu]];*/
	
	return ZKOrig(BOOL, responder);
}

- (void)initializeSubmenusOf:(NSMenu *)menu {
	[[menu delegate] performSelector:@selector(menuWillOpen:) withObject:menu];
	[[menu delegate] performSelector:@selector(menuDidClose:) withObject:menu];

	for (NSMenuItem *menuItem in [menu itemArray]) {
		if ([menuItem hasSubmenu]) {
			[self initializeSubmenusOf:[menuItem submenu]];
		}
		
		[self fixUpMenuItem: menuItem];
	}
}

- (void)fixUpMenuItem:(NSMenuItem *)menuItem {	
	// In Firefox, `Select All` menu item is initially disabled for some reason
	if (![menuItem isEnabled] && [[menuItem title] isEqualToString:NSLocalizedString(@"Select All", nil)]) {
		[menuItem setEnabled:YES];
	}
}

@end




@implementation NSObject (main)

+ (void)load {
	ZKSwizzle(myNSApplication, NSApplication);
	ZKSwizzle(myNSWindow, NSWindow);
}




@end


int main() {}

Default shortcuts still work if nothing else is assigned to them...
Although this doesn't match the behavior of proper cocoa apps,
it's not terrible and I don't see an easy way to fix it.

It is terrible though. I keep hitting Cmd-M by mistake for some reason in daily usage of the Mac, so I reassigned Minimize to Cmd-Opt-Ctrl-Shift-M or something like that, but in Firefox, the app I probably use the most, Cmd-M still minimizes the window.

It is terrible though. I keep hitting Cmd-M by mistake for some reason in daily usage of the Mac, so I reassigned Minimize to Cmd-Opt-Ctrl-Shift-M or something like that, but in Firefox, the app I probably use the most, Cmd-M still minimizes the window.

That’s an annoying use case I didn’t think of! Open to ideas on how to resolve this one.