NSObject+JRSwizzleBlock.[h,m]

gistfile1.m

/* NSObject+JRSwizzleBlock.h */

#import <Foundation/Foundation.h>

@interface NSObject(JRSwizzleBlock)

+ (void)swizzle:(SEL)origmethod toMethod:(SEL)newmethod forBlock:(void(^)(void))swizzledBlock;

@end

/* NSObject+JRSwizzleBlock.m */

#import "NSObject+JRSwizzleBlock.h"
#import <JRSwizzle.h>

@implementation NSObject(JRSwizzleBlock)

+ (void)swizzle:(SEL)origmethod toMethod:(SEL)newmethod forBlock:(void(^)(void))swizzledBlock
{
    if (!swizzledBlock)
        return;
    
    @try
    {
        [self jr_swizzleMethod:origmethod withMethod:newmethod error:nil];
        
        swizzledBlock();
    }
    @finally
    {
        [self jr_swizzleMethod:newmethod withMethod:origmethod error:nil];
    }
}

@end