compact method

@override Future compact()

Compact the database

Implementation

@override
Future compact() async {
  var txn = _idbDatabase.transaction([
    idbInfoStore,
    idbEntryStore,
  ], idbModeReadWrite);
  var deltaMinRevision = await _txnGetDeltaMinRevision(txn);
  var currentRevision = await _txnGetRevision(txn) ?? 0;
  var newDeltaMinRevision = deltaMinRevision;
  var deleteIndex = txn.objectStore(idbEntryStore).index(idbDeletedIndex);
  await deleteIndex.openCursor(autoAdvance: true).listen((cwv) {
    assert(cwv.key is int);
    var revision = cwv.primaryKey as int;
    if (revision > newDeltaMinRevision && revision <= currentRevision) {
      newDeltaMinRevision = revision;
      cwv.delete();
    }
  }).asFuture<void>();
  // devPrint('compact $newDeltaMinRevision vs $deltaMinRevision, $currentRevision');
  if (newDeltaMinRevision > deltaMinRevision) {
    await _txnPutDeltaMinRevision(txn, newDeltaMinRevision);
  }
  await txn.completed;
}