ReactiveCocoa enabled MFMessageComposeViewController

MFMessageComposeViewController.m

//
//  MFMessageComposeViewController+RAC.m
//  Three Cents
//
//  Created by Bob Spryn on 3/3/14.
//  Copyright (c) 2014 Three Cents, Inc. All rights reserved.
//

#import "MFMessageComposeViewController+RAC.h"
#import <objc/objc-runtime.h>

@interface MFMessageComposeViewController() <MFMessageComposeViewControllerDelegate>

@end

@implementation MFMessageComposeViewController (RAC)
- (RACSignal *) rac_messageSignal {
    self.messageComposeDelegate = self;
    RACSignal *signal = objc_getAssociatedObject(self, _cmd);
    if (signal != nil) return signal;
    
    /* Create signal from selector */
    signal = [[self rac_signalForSelector:@selector(messageComposeViewController:didFinishWithResult:)
                    fromProtocol:@protocol(MFMessageComposeViewControllerDelegate)] map:^id(RACTuple *tuple) {
        return tuple.second;
    }];
    
    objc_setAssociatedObject(self, _cmd, signal, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    return signal;
}
@end