During a delete operation, if the deleted node is above its leaf's
parent, this parent will replace the node and then go up. In this
case it is important to update the new parent's scope to reflect
the presence of other branches.
It's worth noting that in theory we should precisely recompute the
exact node value, but it seems that it's not worth it for the rare
cases there is a mismatch.
A new kind of tree nodes is currently being developed in ebtree v7,
consisting in storing a scope in each node indicating a visibility
mask so that certain nodes are not reported on certain lookups. The
initial goal was to make this usable with a multi-thread scheduler.
Since the ebtree v7 code is completely different from v6, this patch
instead copies the minimally required functions from eb32 and ebtree
and calls them "eb32sc_*". At the moment the scope is not implemented,
it's only passed in arguments.
Willy Tarreau