/// <summary>
/// Load the database from disk
/// </summary>
/// <param name="requireLock">True if a lock needs to be acquired before saving</param>
/// <returns></returns>
private async Task LoadDatabaseAsync(bool requireLock = true)
{
if (File.Exists(_config.Filename))
{
if (requireLock)
{
await _dataLock.WaitAsync();
}
try
{
using (var stream = File.OpenRead(_config.Filename))
{
var dbVersion = ReadDbVersion(stream);
// copy the rest of the bytes
var bytes = new byte[stream.Length - stream.Position];
stream.Read(bytes, 0, bytes.Length);
_db = LoadDatabaseByVersion(dbVersion, bytes);
bytes = null;
// could make this non-fatal
if (!ValidateChecksum(_db))
{
throw new Exception("The database did not pass validation! It is either corrupt or has been modified outside of the application.");
}
_primaryKeyTracker = new PrimaryKeyTracker(new Dictionary <string, long>
{
// there is no guaranteed order so we must sort first
{ typeof(Part).Name, _db.Parts.OrderByDescending(x => x.PartId).Select(x => x.PartId).FirstOrDefault() },
{ typeof(PartType).Name, _db.PartTypes.OrderByDescending(x => x.PartTypeId).Select(x => x.PartTypeId).FirstOrDefault() },
});
}
}
catch (Exception ex)
{
throw new Exception("Failed to load database!", ex);
}
finally
{
if (requireLock)
{
_dataLock.Release();
}
}
}
else
{
if (requireLock)
{
await _dataLock.WaitAsync();
}
try
{
_db = NewDatabase();
}
finally
{
if (requireLock)
{
_dataLock.Release();
}
}
}
}