/// <exception cref="System.IO.IOException"/>
private void ReadNextPacket()
{
//Read packet headers.
packetReceiver.ReceiveNextPacket(@in);
PacketHeader curHeader = packetReceiver.GetHeader();
curDataSlice = packetReceiver.GetDataSlice();
System.Diagnostics.Debug.Assert(curDataSlice.Capacity() == curHeader.GetDataLen()
);
if (Log.IsTraceEnabled())
{
Log.Trace("DFSClient readNextPacket got header " + curHeader);
}
// Sanity check the lengths
if (!curHeader.SanityCheck(lastSeqNo))
{
throw new IOException("BlockReader: error in packet header " + curHeader);
}
if (curHeader.GetDataLen() > 0)
{
int chunks = 1 + (curHeader.GetDataLen() - 1) / bytesPerChecksum;
int checksumsLen = chunks * checksumSize;
System.Diagnostics.Debug.Assert(packetReceiver.GetChecksumSlice().Capacity() == checksumsLen
, "checksum slice capacity=" + packetReceiver.GetChecksumSlice().Capacity() + " checksumsLen="
+ checksumsLen);
lastSeqNo = curHeader.GetSeqno();
if (verifyChecksum && curDataSlice.Remaining() > 0)
{
// N.B.: the checksum error offset reported here is actually
// relative to the start of the block, not the start of the file.
// This is slightly misleading, but preserves the behavior from
// the older BlockReader.
checksum.VerifyChunkedSums(curDataSlice, packetReceiver.GetChecksumSlice(), filename
, curHeader.GetOffsetInBlock());
}
bytesNeededToFinish -= curHeader.GetDataLen();
}
// First packet will include some data prior to the first byte
// the user requested. Skip it.
if (curHeader.GetOffsetInBlock() < startOffset)
{
int newPos = (int)(startOffset - curHeader.GetOffsetInBlock());
curDataSlice.Position(newPos);
}
// If we've now satisfied the whole client read, read one last packet
// header, which should be empty
if (bytesNeededToFinish <= 0)
{
ReadTrailingEmptyPacket();
if (verifyChecksum)
{
SendReadResult(DataTransferProtos.Status.ChecksumOk);
}
else
{
SendReadResult(DataTransferProtos.Status.Success);
}
}
}
