Question

I have a sample app that looks like a social network iOS app. I am new to cocoa framework so I’m studying the sample code. Upon hitting analyze, there are 255 reported memory leaks in the app. I was able to solve around 100 of the leaks which were very simple, but I cannot solve the rest.

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict{ 
    //DLog(@"found this element: %@", elementName);
    currentElement = [elementName copy];
    if([MethodName isEqualToString:@"SignInStep"])
    {

        if ([elementName isEqualToString:@"item"]) 
        { // clear out our story item caches... 
            item = [[NSMutableDictionary alloc] init];
            currentUserId = [[NSMutableString alloc] init];

            currentError = [[NSMutableString alloc] init];
        } 

    }

}

Allocation of variables for the item:

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName{ 
    //DLog(@"ended element: %@", elementName);

    if([MethodName isEqualToString:@"SignInStep"])
    {
        if ([elementName isEqualToString:@"item"]) 
        { // save values to an item, then store that item into the array...
            [item setObject:currentUserId forKey:@"userId"]; 

            [item setObject:currentError forKey:@"error"];

            [SignIn addObject:[item copy]];    //Method returns Objective C Object with +1 retain count 

        } 
    } 

}//Object leaked: allocated object is not referenced later in this execution path and has a retain count of +1

I received the following errors:

1) Method returns Objective C Object with +1 retain count

2) Object leaked: allocated object is not referenced later in this execution path and has a retain count of +1

I have mentioned in the above code where exactly I received these leaks. Can anyone tell me what is causing this?

Answer 1

You must relinquish ownership of an object you own

id obj =  [item copy];
[SignIn addObject:obj]; // SignIn will retain obj 
[obj release];  

Take a look at Memory Management Programming Guide

        item = [[NSMutableDictionary alloc] init]; // release this object
        currentUserId = [[NSMutableString alloc] init]; // release this object

        currentError = [[NSMutableString alloc] init]; // release this object