Token Leaks – Initial Design Thoughts

When considering a design to keep track of tokens created, there needed to be an easy way to remove the token once it has been deleted. Tokens left in the list would be memory leaks. The first idea was a simple linked list where each element consisted of a previous link, a next link, a pointer to the token and some type of identifier of where in the code that the Token was allocated. A pointer to the list element would be added to the Token class.

When a token is created, it would be added to the list and a pointer to the list element would be put into the token.  When a token is deleted, it would use the element pointer to delete the item from the list. For tokens still in the list at the end, the identifier would indicate where the token was created, though the contents of the token itself would probably be sufficient in determining why it was not deleted.

At first, a special token list class was considered. It would only need a pointer to the first element in the list. Some code on how this would work (adding and deleted elements) was sketched out.  But wait, there was already a List class, and then it was realized that the List class doesn't need a master element to keep track of the first and last elements in the list. Only a pointer to the first (or last) element is needed...