private TempFile coreDoGetSequential(FileEntryItem item, Interface.IEncryption useDecrypter, out long retDownloadSize, out string retHashcode)
{
retHashcode = null;
retDownloadSize = -1;
TempFile retTarget, dlTarget = null, decryptTarget = null;
try
{
dlTarget = new Library.Utility.TempFile();
if (m_backend is Library.Interface.IStreamingBackend && !m_options.DisableStreamingTransfers)
{
Func<string> getFileHash;
// extended to use stacked streams
using (var fs = System.IO.File.OpenWrite(dlTarget))
using (var hs = GetFileHasherStream(fs, System.Security.Cryptography.CryptoStreamMode.Write, out getFileHash))
using (var ss = new ShaderStream(hs, true))
{
using (var ts = new ThrottledStream(ss, m_options.MaxUploadPrSecond, m_options.MaxDownloadPrSecond))
using (var pgs = new Library.Utility.ProgressReportingStream(ts, item.Size, HandleProgress))
{ ((Library.Interface.IStreamingBackend)m_backend).Get(item.RemoteFilename, pgs); }
ss.Flush();
retDownloadSize = ss.TotalBytesWritten;
retHashcode = getFileHash();
}
}
else
{
m_backend.Get(item.RemoteFilename, dlTarget);
retDownloadSize = new System.IO.FileInfo(dlTarget).Length;
retHashcode = CalculateFileHash(dlTarget);
}
// Decryption is not placed in the stream stack because there seemed to be an effort
// to throw a CryptographicException on fail. If in main stack, we cannot differentiate
// in which part of the stack the source of an exception resides.
if (useDecrypter != null)
{
decryptTarget = new Library.Utility.TempFile();
lock (m_encryptionLock)
{
try { useDecrypter.Decrypt(dlTarget, decryptTarget); }
// If we fail here, make sure that we throw a crypto exception
catch (System.Security.Cryptography.CryptographicException) { throw; }
catch (Exception ex) { throw new System.Security.Cryptography.CryptographicException(ex.Message, ex); }
}
retTarget = decryptTarget;
decryptTarget = null;
}
else
{
retTarget = dlTarget;
dlTarget = null;
}
}
finally
{
if (dlTarget != null) dlTarget.Dispose();
if (decryptTarget != null) decryptTarget.Dispose();
}
return retTarget;
}
