Derive the next track id from stored track data, instead of tracking it explicitly

This saves about 1ms per new track right now, but more importantly means
that minting a new track id is now a single atomic operation, rather
than being its own database write. This is a useful property that will
come in handy in a few commits time.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/tangara/database/database.hpp b/src/tangara/database/database.hpp
index c2e72568..2b385013 100644
--- a/src/tangara/database/database.hpp
+++ b/src/tangara/database/database.hpp
@@ -100,6 +100,7 @@ class Database {
   locale::ICollator& collator_;
 
   std::atomic<bool> is_updating_;
+  std::atomic<TrackId> next_track_id_;
 
   Database(leveldb::DB* db,
            leveldb::Cache* cache,
@@ -107,6 +108,7 @@ class Database {
            ITagParser& tag_parser,
            locale::ICollator& collator);
 
+  auto dbCalculateNextTrackId() -> void;
   auto dbMintNewTrackId() -> TrackId;
 
   auto dbEntomb(TrackId track, uint64_t hash) -> void;