libstage: s/match/lookup/g

Rather than having a per-node match function to facilitate stage
lookups by opaque keys returning a boolean result, make it a
more general lookup returning a stage_t *.

It's still basically a boolean, where NULL is a miss.  But by
returning the stage_t *, it enables things like encapsulated
stages for caching purposes where a node might represent an
isolated stage it can propagate lookups down to and return
the results out of.

When the match function only returned a 1/0, and the outer
lookup machinery returned the current stage node on a hit,
there was no way to hand out arbitrary stage pointers.

0 files changed, 0 insertions, 0 deletions