gistfile1.m

#import "UINavigationController+RACSignalSupport.h"

#import <ReactiveCocoa/ReactiveCocoa.h>
#import <ReactiveCocoa/RACDelegateProxy.h>
#import <ReactiveCocoa/NSObject+RACDescription.h>

#import <objc/runtime.h>

@implementation UIImagePickerController (RACSignalSupport)

-(Protocol*)rac_delegateProtocol
{
   return @protocol(UIImagePickerControllerDelegate);
}

@end

@implementation UINavigationController (RACSignalSupport)

static void RACUseDelegateProxy(UINavigationController *self)
{
   if (self.delegate == self.rac_delegateProxy) return;
   
   self.rac_delegateProxy.rac_proxiedDelegate = self.delegate;
   self.delegate = (id)self.rac_delegateProxy;
}

-(Protocol*)rac_delegateProtocol
{
   return @protocol(UINavigationControllerDelegate);
}

-(RACDelegateProxy*)rac_delegateProxy
{
	RACDelegateProxy *proxy = objc_getAssociatedObject(self, _cmd);
	if (proxy == nil) {
		proxy = [[RACDelegateProxy alloc] initWithProtocol:[self rac_delegateProtocol]];
		objc_setAssociatedObject(self, _cmd, proxy, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
	}
   
	return proxy;
}

-(RACSignal*)rac_willShowViewControllerSignal
{
   RACSignal* signal_ =
   [ [ [ self.rac_delegateProxy
        signalForSelector:@selector(navigationController:willShowViewController:animated:)]
      reduceEach:
      ^( UINavigationController* navigation_controller_, UIViewController* controller_, NSNumber* _ )
      {
         return controller_;
      }]
    takeUntil: self.rac_willDeallocSignal ];
   
   RACUseDelegateProxy(self);
   
   return signal_;
}

-(RACSignal*)rac_didShowViewControllerSignal
{
   RACSignal* signal_ =
   [ [ [ self.rac_delegateProxy
        signalForSelector:@selector(navigationController:didShowViewController:animated:)]
      reduceEach:
      ^( UINavigationController* navigation_controller_, UIViewController* controller_, NSNumber* _ )
      {
         return controller_;
      }]
    takeUntil: self.rac_willDeallocSignal ];

   RACUseDelegateProxy(self);

   return signal_;
}

@end