/// <summary>
/// Initialize LiteEngine using initial engine settings
/// </summary>
public LiteEngine(EngineSettings settings)
{
_settings = settings ?? throw new ArgumentNullException(nameof(settings));
// clear checkpoint if database is readonly
if (_settings.ReadOnly)
{
_settings.Checkpoint = 0;
}
LOG($"start initializing{(_settings.ReadOnly ? " (readonly)" : "")}", "ENGINE");
try
{
// create new flip coin
_flipCoin = new FlipCoin(settings.Seed);
// initialize locker service (no dependency)
_locker = new LockService(settings.Timeout, settings.ReadOnly);
// initialize disk service (will create database if needed)
_disk = new DiskService(settings);
// read page with no cache ref (has a own PageBuffer) - do not Release() support
var buffer = _disk.ReadFull(FileOrigin.Data).First();
// if first byte are 1 this datafile are encrypted but has do defined password to open
if (buffer[0] == 1)
{
throw new LiteException(0, "This data file is encrypted and needs a password to open");
}
_header = new HeaderPage(buffer);
// initialize wal-index service
_walIndex = new WalIndexService(_disk, _locker);
// if exists log file, restore wal index references (can update full _header instance)
if (_disk.GetLength(FileOrigin.Log) > 0)
{
_walIndex.RestoreIndex(ref _header);
}
// initialize sort temp disk
_sortDisk = new SortDisk(settings.CreateTempFactory(), CONTAINER_SORT_SIZE, settings.UtcDate);
// initialize transaction monitor as last service
_monitor = new TransactionMonitor(_header, _locker, _disk, _walIndex, _settings);
// register system collections
this.InitializeSystemCollections();
LOG("initialization completed", "ENGINE");
}
catch (Exception ex)
{
LOG(ex.Message, "ERROR");
// explicit dispose (but do not run shutdown operation)
this.Dispose(true);
throw;
}
}
/// <summary>
/// Insert a new node index inside an collection index. Flip coin to know level
/// </summary>
public IndexNode AddNode(CollectionIndex index, BsonValue key, PageAddress dataBlock, IndexNode last, FlipCoin flipCoin)
{
// do not accept Min/Max value as index key (only head/tail can have this value)
if (key.IsMaxValue || key.IsMinValue)
{
throw LiteException.InvalidIndexKey($"BsonValue MaxValue/MinValue are not supported as index key");
}
// random level (flip coin mode) - return number between 1-32
var level = flipCoin.Flip();
// set index collection with max-index level
if (level > index.MaxLevel)
{
// update max level
_snapshot.CollectionPage.UpdateCollectionIndex(index.Name).MaxLevel = level;
}
// call AddNode with key value
return(this.AddNode(index, key, dataBlock, level, last));
}