Why is my code leaking?

Question

UPDATE2 I think I found the true source of the leaks. I had some business objects that have string properties I forgot to release. These string properties were copied from my custom xlm node object, created here (KGYXMLNode) I don't understandt why the leak is reported here instead of my custom class. My NSString properties were copy and not retain.

UPDATE: I think it was a bug in Instruments or something or it doesn't magically leak anymore, but since xcode 4 it doesn't show this leak.

Hello, according to instruments i have a leak in the following code. I've built an objective-c wrapper around certain libxml functions to be able to parse xml docs using xpath, and in this method I'm setting the innerText for my custom node object.

-(void) SetInnerTextForNode: (xmlNodePtr) node : (KGYXMLNode *) obcNode
{
  if ((node) && (node->children))
  {
    for (xmlNodePtr pnode = node->children; pnode != NULL; pnode = pnode->next)
    {
      if (pnode->type == XML_TEXT_NODE)
      {
        xmlChar *content = pnode->content;
        NSString *innerText = [[NSString alloc] initWithUTF8String: (char *)content];
        NSString *trimmedText = [innerText stringByTrimmingCharactersInSet: trimCharSet];
        if (trimmedText.length > 0)
          obcNode.innerText = trimmedText;
        [innerText release];
        break;
      }
    }
  }
}

The leak is NSString *innerText = [[NSString alloc] initWithUTF8String: (char *)content];. I don't know what is wrong.

Answer 1

You shouldn't access a node's content directly, instead use xmlNodeGetContent:

        xmlChar *content = xmlNodeGetContent(pnode);
        NSString *innerText = [[NSString alloc] initWithUTF8String: (char *)content];
        NSString *trimmedText = [innerText stringByTrimmingCharactersInSet: trimCharSet];
        if (trimmedText.length > 0)
          obcNode.innerText = trimmedText;
        [innerText release];
        // you must free what xmlNodeGetContent returns!
        xmlFree(content);
        break;

Answer 2

I don't know why your code is leaking, but it seems to me that you have an unsafe assignment of an autoreleased object to obcNode.innerText without retaining it.