//

 //  NullSafe.m

 //

 //  Version 1.2.2

 //

 //  Created by Nick Lockwood on 19/12/2012.

 //  Copyright 2012 Charcoal Design

 //

 //  Distributed under the permissive zlib License

 //  Get the latest version from here:

 //

 //  https://github.com/nicklockwood/NullSafe

 //

 //  This software is provided 'as-is', without any express or implied

 //  warranty.  In no event will the authors be held liable for any damages

 //  arising from the use of this software.

 //

 //  Permission is granted to anyone to use this software for any purpose,

 //  including commercial applications, and to alter it and redistribute it

 //  freely, subject to the following restrictions:

 //

 //  1. The origin of this software must not be misrepresented; you must not

 //  claim that you wrote the original software. If you use this software

 //  in a product, an acknowledgment in the product documentation would be

 //  appreciated but is not required.

 //

 //  2. Altered source versions must be plainly marked as such, and must not be

 //  misrepresented as being the original software.

 //

 //  3. This notice may not be removed or altered from any source distribution.

 //

 //Fix  issue      desc = "<null>";icon = "<null>";

 #import <objc/runtime.h>

 #import <Foundation/Foundation.h>

 #ifndef NULLSAFE_ENABLED

 #define NULLSAFE_ENABLED 1

 #endif

 #pragma GCC diagnostic ignored "-Wgnu-conditional-omitted-operand"

 @implementation NSNull (NullSafe)

 #if NULLSAFE_ENABLED

 - (NSMethodSignature *)methodSignatureForSelector:(SEL)selector

 {

     @synchronized([self class])

     {

         //look up method signature

         NSMethodSignature *signature = [super methodSignatureForSelector:selector];

         if (!signature)

         {

             //not supported by NSNull, search other classes

             static NSMutableSet *classList = nil;

             static NSMutableDictionary *signatureCache = nil;

             if (signatureCache == nil)

             {

                 classList = [[NSMutableSet alloc] init];

                 signatureCache = [[NSMutableDictionary alloc] init];

                 //get class list

                 int numClasses = objc_getClassList(NULL, );

                 Class *classes = (Class *)malloc(sizeof(Class) * (unsigned long)numClasses);

                 numClasses = objc_getClassList(classes, numClasses);

                 //add to list for checking

                 NSMutableSet *excluded = [NSMutableSet set];

                 for (int i = ; i < numClasses; i++)

                 {

                     //determine if class has a superclass

                     Class someClass = classes[i];

                     Class superclass = class_getSuperclass(someClass);

                     while (superclass)

                     {

                         if (superclass == [NSObject class])

                         {

                             [classList addObject:someClass];

                             break;

                         }

                         [excluded addObject:NSStringFromClass(superclass)];

                         superclass = class_getSuperclass(superclass);

                     }

                 }

                 //remove all classes that have subclasses

                 for (Class someClass in excluded)

                 {

                     [classList removeObject:someClass];

                 }

                 //free class list

                 free(classes);

             }

             //check implementation cache first

             NSString *selectorString = NSStringFromSelector(selector);

             signature = signatureCache[selectorString];

             if (!signature)

             {

                 //find implementation

                 for (Class someClass in classList)

                 {

                     if ([someClass instancesRespondToSelector:selector])

                     {

                         signature = [someClass instanceMethodSignatureForSelector:selector];

                         break;

                     }

                 }

                 //cache for next time

                 signatureCache[selectorString] = signature ?: [NSNull null];

             }

             else if ([signature isKindOfClass:[NSNull class]])

             {

                 signature = nil;

             }

         }

         return signature;

     }

 }

 - (void)forwardInvocation:(NSInvocation *)invocation

 {

     invocation.target = nil;

     [invocation invoke];

 }

 #endif

 @end