tree 83b2ce2d99ba3a245a45206ee917bf192a61db00
parent 77c2325eb540437a140bd3d3a38499b91c8597a9
author Ivan Frade <ifrade@google.com> 1574448875 -0800
committer Ivan Frade <ifrade@google.com> 1733332161 -0800

VisibilityCache/Checker: Use streams for the reachability starters

The materialized collection of starters performs the potentially
expensive ObjectId to RevCommit translation, but probably many commits
won't be needed at all in an incremental reachability check.

Use streams to pass the starters to the reachability checker, delaying
the ObjectId to RevCommit translation until it is really needed.

Note that for repositories without bitmaps the performance could vary.
Before, it was setting some start points, walk, set new start points,
walk.... until finding the required commit. Now it will set all start
points from the beginning. This increases the cost to start walking,
(but could also avoid re-walking previously visited nodes).

Change-Id: Ifa58e8e7f4cf44e30e1ff57d5a60f24378181f56