Fix iOS 16 crash on [UIKeyboardTaskQueue promoteDeferredTaskIfIdle]

iOS16KeyboardFixer.m

#import <Foundation/Foundation.h>
#import <objc/runtime.h>

@interface UIDeferredTasksWrapper : NSProxy
- (instancetype)initWithArray:(NSMutableArray *)array;
@end

@implementation UIDeferredTasksWrapper
{
    NSMutableArray <id>     * _tasks;
}

- (instancetype)initWithArray:(NSMutableArray *)array {
    if (self) {
        _tasks = array;
    }
    return self;
}

- (NSMethodSignature *)methodSignatureForSelector:(SEL)sel {
    return [_tasks methodSignatureForSelector:sel];
}

- (void)forwardInvocation:(NSInvocation *)invocation {
    static dispatch_once_t onceToken;
    static dispatch_queue_t taskQueue = nil;
    dispatch_once(&onceToken, ^{
        taskQueue = dispatch_queue_create("com.apple.keyboardTaskQueue", DISPATCH_QUEUE_SERIAL);
    });
    
    dispatch_sync(taskQueue, ^{
        [invocation invokeWithTarget:_tasks];
    });
}

@end

static IMP origin_keyboard_task_queue_init = NULL;
static id new_keyboard_task_queue_init(id self, SEL _cmd) {
    NSString *ivarName = @"_deferredTasks";
    
    id(*init)(id, SEL) = (id(*)(id, SEL))origin_keyboard_task_queue_init;
    id instance = init(self, _cmd);
    id member = [instance valueForKey:ivarName];
    if ([member isKindOfClass:NSMutableArray.class]) {
        [instance setValue:[[UIDeferredTasksWrapper alloc] initWithArray:member]
                    forKey:ivarName];
    }
    return instance;
}

void __FIX_iOS_16_KEYBOARD_TASK_QUEUE_CRASH__(void) {
    float system = [UIDevice currentDevice].systemVersion.floatValue;
    if (16.0 <= system && system < 17.0) {
        static dispatch_once_t onceToken;
        dispatch_once(&onceToken, ^{
            Class cls = NSClassFromString(@"UIKeyboardTaskQueue");
            if (cls) {
                /// swizzle
                /// @code
                /// -[UIKeyboardTaskQueue init]
                /// @endcode
                /// then replace member @c _deferredTasks with thread safe proxy
                Method init_m = class_getInstanceMethod(cls, @selector(init));
                origin_keyboard_task_queue_init = method_setImplementation(init_m, (IMP)new_keyboard_task_queue_init);
            }
        });
    }
}