Category to add Async methods to the FMDatabaseQueue

FMDatabaseQueue+async.mm

//
//  FMDatabaseQueue+async.h
//
//  Created by Jonathan Dalrymple on 05/02/2013.
//

#import <FMDB/FMDatabaseQueue.h>
#import <objc/runtime.h>

const static char *propertyName = "FR_asyncQueueProperty";

@interface FMDatabaseQueue (async)

@property (nonatomic,strong) dispatch_queue_t asyncQueue;

- (void)asyncInDatabase:(void (^)(FMDatabase *db))aBlock;
- (void)asyncInTransaction:(void (^)(FMDatabase *db, BOOL *rollback))aBlock;

@end

@implementation FMDatabaseQueue (async)

- (void)setAsyncQueue:(dispatch_queue_t)asyncQueue {
  objc_setAssociatedObject(self, propertyName, asyncQueue, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (dispatch_queue_t)asyncQueue {
  
  dispatch_queue_t queue = NULL;

  if (!(queue = objc_getAssociatedObject(self, propertyName))) {
    queue = dispatch_queue_create("com.FMDatabaseQueue.async", DISPATCH_QUEUE_SERIAL);
    [self setAsyncQueue:queue];
  }
  
  return queue;
}

- (void)asyncInDatabase:(void (^)(FMDatabase *db))aBlock {
  
  __unsafe_unretained id weakSelf = self;
  
  dispatch_async([self asyncQueue], ^{
    
    [weakSelf inDatabase:aBlock];
    
  });
  
}

- (void)asyncInTransaction:(void (^)(FMDatabase *db, BOOL *rollback))aBlock {
  
  __unsafe_unretained id weakSelf = self;
  
  dispatch_async([self asyncQueue], ^{
    
    [weakSelf inTransaction:aBlock];
    
  });
  
}

@end