When doing prefix scans in the database, "foo" should not be considered
a prefix of "foo2". Instead, it should match "foo" exactly and also
strings with the prefix "foo/". This is more restrictive than what the
standard leveldb prefix scan does so we add some code to enforce it.
Also exposes the initialScanCompleted on the rwfolder for testing, and
change it to be a channel (so we can wait for it from another
goroutine). Otherwise we can't be sure when the initial scan has
completed, and we need to wait for that or it might pick up changes
we're doing at an unexpected time.
GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3067
This happens automatically in the background anyway, and it can take a
long time on low powered devices at an inconvenient time. We just want
to get up and running as quickly as possible.
GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3000
We're going to need the db.Instance to keep some state, and for that to
work we need the same one passed around everywhere. Hence this moves the
leveldb-specific file opening stuff into the db package and exports the
dbInstance type.
