I've tested the behavior of the thread that waits for the LiveUpdate to
be finished, and it does get signaled and exit cleanly when the
LiveUpdate is GCed instead.
Made finishedLiveUpdate wait for the thread to finish updating the
database.
There is a case where GC doesn't happen in time and the database is left
with a live update recorded in it. This should not be a problem as such
stale data can also happen when interrupted and will need to be detected
when loading the database.
Balanced preferred content expressions now call startLiveUpdate.
Each command that first checks preferred content (and/or required
content) and then does something that can change the sizes of
repositories needs to call prepareLiveUpdate, and plumb it through the
preferred content check and the location log update.
So far, only Command.Drop is done. Many other commands that don't need
to do this have been updated to keep working.
There may be some calls to NoLiveUpdate in places where that should be
done. All will need to be double checked.
Not currently in a compilable state.
The use of catObjectStream is optimally fast. Although it might be
possible to combine this with git-annex branch merge to avoid some
redundant work.
Benchmarking, a git-annex branch that had 100000 files changed
took less than 1.88 seconds to run through this.
