/// <summary>
/// Processes the specified depot key by decrypting the data with the given depot encryption key, and then by decompressing the data.
/// If the chunk has already been processed, this function does nothing.
/// </summary>
/// <param name="depotKey">The depot decryption key.</param>
/// <exception cref="System.IO.InvalidDataException">Thrown if the processed data does not match the expected checksum given in it's chunk information.</exception>
public void Process(byte[] depotKey)
{
if (depotKey == null)
{
throw new ArgumentNullException(nameof(depotKey));
}
if (IsProcessed)
{
return;
}
byte[] processedData = CryptoHelper.SymmetricDecrypt(Data, depotKey);
if (processedData.Length > 1 && processedData[0] == 'V' && processedData[1] == 'Z')
{
processedData = VZipUtil.Decompress(processedData);
}
else
{
processedData = ZipUtil.Decompress(processedData);
}
DebugLog.Assert(ChunkInfo.Checksum != null, nameof(DepotChunk), "Expected data chunk to have a checksum.");
byte[] dataCrc = CryptoHelper.AdlerHash(processedData);
if (!dataCrc.SequenceEqual(ChunkInfo.Checksum))
{
throw new InvalidDataException("Processed data checksum is incorrect! Downloaded depot chunk is corrupt or invalid/wrong depot key?");
}
Data = processedData;
IsProcessed = true;
}
public void Work()
{
Task = Task.Factory.StartNew(async() =>
{
while (!_stop || !_filesHandler._downloadedChunksBuffer.IsEmpty)
{
if (_filesHandler._downloadedChunksBuffer.IsEmpty)
{
await Task.Delay(100);
}
bool hasData = _filesHandler._downloadedChunksBuffer.TryDequeue(out (ChunkTask chunkTask, byte[] data)availableData);
if (!hasData)
{
continue;
}
try
{
var depotChunk = new SteamKit2.CDNClient.DepotChunk(availableData.chunkTask.InternalChunk, availableData.data);
var verified = false;
if (_filesHandler._depotKey != null)
{
depotChunk.Process(_filesHandler._depotKey);
verified = true;
}
if (!verified)
{
using (SHA1Managed sha1 = new SHA1Managed())
{
if (!depotChunk.ChunkInfo.Checksum.SequenceEqual(CryptoHelper.AdlerHash(depotChunk.Data)))
{
throw new InvalidOperationException("Invalid chunk data received.");
}
}
}
await availableData.chunkTask.FileWriter.WriteAsync(availableData.chunkTask.Chunk.Offset, depotChunk.Data);
}
catch (InvalidOperationException)
{
_filesHandler._chunks.Enqueue(availableData.chunkTask);
}
catch (Exception ex)
{
throw new SteamDownloadTaskFileTargetWrappedException(availableData.chunkTask.FileWriter.Target, ex);
}
}
}, TaskCreationOptions.LongRunning).GetAwaiter().GetResult();
}
