error handling

BNRDocument.m

- (BOOL)readFromData:(NSData *)data ofType:(NSString *)typeName error:(NSError **)outError
{
    todoItems = [NSPropertyListSerialization propertyListWithData:data options:NSPropertyListMutableContainers format:NULL error:outError];

    BOOL errorFound = todoItems == nil;
    
    if (errorFound) 
    {        
        NSMutableDictionary *userInfo = [NSMutableDictionary dictionary];
        [userInfo setValue:@"Custom Error Description"      forKey:NSLocalizedDescriptionKey];
        [userInfo setValue:@"Custom Failure Reason"         forKey:NSLocalizedFailureReasonErrorKey];
        [userInfo setValue:@"Custom Recovery Suggestion"    forKey:NSLocalizedRecoverySuggestionErrorKey];
        
        NSError *myError = 
        [NSError errorWithDomain:@"My Custom Domain" code:41 userInfo:userInfo];
        
        [NSApp presentError:myError];
        
        *outError = [NSError errorWithDomain:NSCocoaErrorDomain code:NSUserCancelledError userInfo:nil];
        
    }
    
    return !errorFound;
}