Importing from a newer prefs file

gistfile1.m

@implementation NSUserDefaults (RSFoundation)

+ (BOOL) rsImportPreferencesFromBundleID:(NSString*)otherBundleID ifNewerThanBundleID:(NSString*)ourBundleID
{
	BOOL didMigrate = NO;
	
	NSArray* libraryFolders = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
	if ([libraryFolders count] > 0)
	{
		NSString* prefsFolder = [[libraryFolders objectAtIndex:0] stringByAppendingPathComponent:@"Preferences"];
		NSString* otherPreferencesFileName = [otherBundleID stringByAppendingPathExtension:@"plist"];
		NSString* ourPreferencesFileName = [ourBundleID stringByAppendingPathExtension:@"plist"];
		NSString* otherPreferencesFile = [prefsFolder stringByAppendingPathComponent:otherPreferencesFileName];
		NSString* ourPreferencesFile = [prefsFolder stringByAppendingPathComponent:ourPreferencesFileName];
		NSFileManager* fm = [NSFileManager defaultManager];
		if ([fm fileExistsAtPath:otherPreferencesFile])
		{
			NSDate* otherModDate = [fm lastModDateAtPath:otherPreferencesFile];
			NSDate* ourModDate = [fm lastModDateAtPath:ourPreferencesFile];
			if ((ourModDate == nil) || ([ourModDate compare:otherModDate] == NSOrderedAscending))
			{
				NSUserDefaults* sud = [NSUserDefaults standardUserDefaults];
				NSDictionary *newerPrefs = [sud persistentDomainForName:otherBundleID];
				if (newerPrefs != nil)
				{		
					// Swap the old prefs in as our own 
					[sud setPersistentDomain:newerPrefs forName:ourBundleID];
					
					[NSUserDefaults resetStandardUserDefaults];
					
					// Log about it 
					NSLog(@"Found newer preferences in %@ - importing", otherPreferencesFileName);
					
					didMigrate = YES;
				}			
			}
		}
	}
	
	return didMigrate;
}

@end