Nested iteration

[thejpster]

You can't open a child directory whilst iterating a directory. We should support that because otherwise you have to cache all the child names and then do an expensive directory walk to find them again.

If we were smart we'd let you trade one directory handle for another and use .. to pop back, so we only have one directory open at once.

[thejpster]

If we were smart we'd let you trade one directory handle for another

Actually, no, you need a stack because you want to come back to the parent dir and resume at the entry just after the child.