An NSObject category (Obj-C) to perform code blocks in particular threads and with different priorities

NSObject+performBlock.h

//
//  NSObject+performBlock.h
//

#import <Foundation/Foundation.h>

/**
 An NSObject category to perform code blocks in particular threads and with different priorities
 */
@interface NSObject (PerformBlock)

- (void) performBlock:(void(^)(void))block;
- (void) performBlock:(void(^)(void))block afterDelay:(double)delayInSeconds;

- (void) performBlockInBackgroundQueue:(void(^)(void))block;
- (void) performBlockInBackgroundQueue:(void(^)(void))block afterDelay:(double)delayInSeconds;

- (void) performBlockOnMainQueue:(void(^)(void))block;
- (void) performBlockOnMainQueue:(void(^)(void))block afterDelay:(double)delayInSeconds;

- (void) performBlockOnMainQueueWithHighPriority:(void(^)(void))block;
- (void) performBlockOnMainQueueWithHighPriority:(void(^)(void))block afterDelay:(double)delayInSeconds;

@end

NSObject+performBlock.m

//
//  NSObject+performBlock.m
//

#import "NSObject+performBlock.h"

@implementation NSObject (PerformBlock)

- (void) performBlock:(void(^)(void))block {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), block);
}
- (void) performBlock:(void(^)(void))block afterDelay:(double)delayInSeconds {
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
    dispatch_after(popTime, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), block);
}

- (void) performBlockInBackgroundQueue:(void(^)(void))block {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), block);
}
- (void) performBlockInBackgroundQueue:(void(^)(void))block afterDelay:(double)delayInSeconds {
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
    dispatch_after(popTime, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), block);
}

- (void) performBlockOnMainQueue:(void(^)(void))block {
    dispatch_async(dispatch_get_main_queue(), block);
}
- (void) performBlockOnMainQueue:(void(^)(void))block afterDelay:(double)delayInSeconds {
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
    dispatch_after(popTime, dispatch_get_main_queue(), block);
}

- (void) performBlockOnMainQueueWithHighPriority:(void(^)(void))block {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), block);
}
- (void) performBlockOnMainQueueWithHighPriority:(void(^)(void))block afterDelay:(double)delayInSeconds {
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
    dispatch_after(popTime, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), block);
}

@end