// Todo: Cancel or wait for any unfinished operations (queries, etc.) when reloading the database.
internal Task LoadAsync(IDatabaseLoadMethod loadMethod,
CancellationToken cancellationToken = default(CancellationToken))
{
if (loadMethod == null)
{
throw new ArgumentNullException(nameof(loadMethod));
}
return(Task.Run(() =>
{
if (cancellationToken.IsCancellationRequested)
{
return;
}
lock (DbWriteLock)
{
var databaseItems = new ConcurrentList <Entity>();
List <Entity> previousItems;
using (var e = volatileDatabaseItems.GetEnumerator(cancellationToken))
{
previousItems = e.AsEnumerable().ToList();
}
if (cancellationToken.IsCancellationRequested)
{
return;
}
volatileDatabaseItems = databaseItems;
try
{
Log(new DatabaseEvent(DatabaseEventType.LoadStart, message: "Database load started."));
if (loadMethod.Scannable)
{
Log(new DatabaseEvent(DatabaseEventType.ScanStart, message: "Scan started."));
loadMethod.Scan(previousItems, Logger, cancellationToken);
if (cancellationToken.IsCancellationRequested)
{
return;
}
foreach (var item in previousItems)
{
databaseItems.Add(item);
}
Log(new DatabaseEvent(DatabaseEventType.ScanEnd, message: "Scan ended."));
Log(new DatabaseEvent(DatabaseEventType.LoadProgress,
message: $"Load progress: 0 / {loadMethod.ItemCount:n0}",
progress: new Progress(0, loadMethod.ItemCount)));
}
var items = loadMethod.Load(Logger);
var stopwatch = new Stopwatch();
stopwatch.Start();
var i = -1;
foreach (var item in items)
{
i++;
if (cancellationToken.IsCancellationRequested)
{
break;
}
if (item != null)
{
databaseItems.Add(item);
}
if (loadMethod.Scannable)
{
if (stopwatch.ElapsedMilliseconds >= ProgressEventDelay)
{
Log(new DatabaseEvent(DatabaseEventType.LoadProgress,
progress: new Progress(i + 1, loadMethod.ItemCount)));
stopwatch.Restart();
}
}
}
}
catch (Exception ex)
{
Log(new DatabaseEvent(
DatabaseEventType.Message, message: $"Database load error: {ex.Message}",
severity: EventSeverity.Error));
}
finally
{
databaseItems.CompleteAdding();
Log(new DatabaseEvent(DatabaseEventType.LoadEnd, message: "Database load ended."));
}
}
}, cancellationToken));
}
/// <summary>
/// A high-level database save/load method that handles caching automatically.
/// </summary>
/// <param name="connection"></param>
/// <param name="directory"></param>
/// <param name="cacheDirectory"></param>
/// <param name="mode"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
public static Task LoadAsync(
this IDatabaseConnection connection,
string directory,
string cacheDirectory,
DatabaseLoadMode mode = DatabaseLoadMode.Auto,
CancellationToken cancellationToken = default(CancellationToken))
{
if (connection == null)
{
throw new ArgumentNullException(nameof(connection));
}
if (directory == null)
{
throw new ArgumentNullException(nameof(directory));
}
if (cacheDirectory == null)
{
throw new ArgumentNullException(nameof(cacheDirectory));
}
return(Task.Run(async() =>
{
var cacheFilePath = Path.Combine(cacheDirectory, IO.IOUtil.PathToHash(directory));
IDatabaseLoadMethod loadMethod = null;
IDatabaseSaveMethod saveMethod = null;
try
{
switch (mode)
{
case DatabaseLoadMode.Auto:
if (File.Exists(cacheFilePath))
{
goto case DatabaseLoadMode.LoadCache;
}
else
{
goto case DatabaseLoadMode.Rebuild;
}
case DatabaseLoadMode.LoadCache:
loadMethod = new SerializedDatabaseLoadMethod(cacheFilePath);
break;
case DatabaseLoadMode.Rebuild:
loadMethod = new CreateFromDirectoryDatabaseLoadMethod(directory, FileIOUtil.CreateOmniFileHandler());
saveMethod = new SerializedDatabaseSaveMethod(cacheFilePath);
break;
case DatabaseLoadMode.Refresh:
loadMethod = new CreateFromDirectoryDatabaseLoadMethod(directory, FileIOUtil.CreateOmniFileHandler(), update: true);
saveMethod = new SerializedDatabaseSaveMethod(cacheFilePath);
break;
default:
throw new ArgumentOutOfRangeException(nameof(mode), mode, null);
}
await connection.LoadAsync(loadMethod, cancellationToken);
if (saveMethod != null)
{
await connection.SaveAsync(saveMethod, cancellationToken);
}
}
catch (TaskCanceledException)
{
}
finally
{
loadMethod?.Dispose();
saveMethod?.Dispose();
}
}, cancellationToken));
}
