TiFilesystemFileProxy.m

-(NSNumber*)remoteBackup
{
    NSURL *URL= [NSURL fileURLWithPath: [self path]];
    NSError *error;
    NSNumber *result = nil;
   
    BOOL success = [URL getResourceValue:&result
                                  forKey:NSURLIsExcludedFromBackupKey error:&error];
    if (!success) {
        // Doesn't matter what error is set to; this means that we're backing up.
        return NUMBOOL(YES);
    }

    // A value of 0 means backup, so:
    return NUMBOOL([result isEqualToNumber:@YES] ? NO : YES);
}

-(void)setRemoteBackup:(id)remoteBackup
{
    ENSURE_TYPE(remoteBackup, NSNumber);
    
    BOOL isExcluced = ![TiUtils boolValue:remoteBackup def:YES];
    NSURL *URL= [NSURL fileURLWithPath: [self path]];
    NSError *error;
    
    BOOL success = [URL setResourceValue: NUMBOOL(isExcluced)
                                  forKey: NSURLIsExcludedFromBackupKey error: &error];
    if (!success) {
        [self throwException:@"Error setting remote backup flag:"
                   subreason:[error localizedDescription]
                    location:CODELOCATION];
    }
}