/// <summary>
/// Sends the specified packet to this node.
/// </summary>
/// <param name="packet">The packet to send.</param>
public void SendData(INodePacket packet)
{
MemoryStream writeStream = new MemoryStream();
ITranslator writeTranslator = BinaryTranslator.GetWriteTranslator(writeStream);
try
{
writeStream.WriteByte((byte)packet.Type);
// Pad for the packet length
writeStream.Write(BitConverter.GetBytes((int)0), 0, 4);
packet.Translate(writeTranslator);
// Now plug in the real packet length
writeStream.Position = 1;
writeStream.Write(BitConverter.GetBytes((int)writeStream.Length - 5), 0, 4);
byte[] writeStreamBuffer = writeStream.GetBuffer();
for (int i = 0; i < writeStream.Length; i += MaxPacketWriteSize)
{
int lengthToWrite = Math.Min((int)writeStream.Length - i, MaxPacketWriteSize);
if ((int)writeStream.Length - i <= MaxPacketWriteSize)
{
// We are done, write the last bit asynchronously. This is actually the general case for
// most packets in the build, and the asynchronous behavior here is desirable.
#if FEATURE_APM
_serverToClientStream.BeginWrite(writeStreamBuffer, i, lengthToWrite, PacketWriteComplete, null);
#else
_serverToClientStream.WriteAsync(writeStreamBuffer, i, lengthToWrite);
#endif
return;
}
else
{
// If this packet is longer that we can write in one go, then we need to break it up. We can't
// return out of this function and let the rest of the system continue because another operation
// might want to send data immediately afterward, and that could result in overlapping writes
// to the pipe on different threads.
#if FEATURE_APM
IAsyncResult result = _serverToClientStream.BeginWrite(writeStream.GetBuffer(), i, lengthToWrite, null, null);
_serverToClientStream.EndWrite(result);
#else
_serverToClientStream.Write(writeStreamBuffer, i, lengthToWrite);
#endif
}
}
}
catch (IOException e)
{
// Do nothing here because any exception will be caught by the async read handler
CommunicationsUtilities.Trace(_nodeId, "EXCEPTION in SendData: {0}", e);
}
catch (ObjectDisposedException) // This happens if a child dies unexpectedly
{
// Do nothing here because any exception will be caught by the async read handler
}
}
/// <summary>
/// Actually writes and sends the packet. This can't be called in parallel
/// because it reuses the _writeBufferMemoryStream, and this is why we use
/// the _packetWriteDrainTask to serially chain invocations one after another.
/// </summary>
/// <param name="packet">The packet to send.</param>
private void SendDataCore(INodePacket packet)
{
MemoryStream writeStream = _writeBufferMemoryStream;
// clear the buffer but keep the underlying capacity to avoid reallocations
writeStream.SetLength(0);
ITranslator writeTranslator = BinaryTranslator.GetWriteTranslator(writeStream);
try
{
writeStream.WriteByte((byte)packet.Type);
// Pad for the packet length
WriteInt32(writeStream, 0);
packet.Translate(writeTranslator);
int writeStreamLength = (int)writeStream.Position;
// Now plug in the real packet length
writeStream.Position = 1;
WriteInt32(writeStream, writeStreamLength - 5);
byte[] writeStreamBuffer = writeStream.GetBuffer();
for (int i = 0; i < writeStreamLength; i += MaxPacketWriteSize)
{
int lengthToWrite = Math.Min(writeStreamLength - i, MaxPacketWriteSize);
_serverToClientStream.Write(writeStreamBuffer, i, lengthToWrite);
}
if (IsExitPacket(packet))
{
_exitPacketState = ExitPacketState.ExitPacketSent;
}
}
catch (IOException e)
{
// Do nothing here because any exception will be caught by the async read handler
CommunicationsUtilities.Trace(_nodeId, "EXCEPTION in SendData: {0}", e);
}
catch (ObjectDisposedException) // This happens if a child dies unexpectedly
{
// Do nothing here because any exception will be caught by the async read handler
}
}
private void RunReadLoop(Stream localReadPipe, Stream localWritePipe,
ConcurrentQueue <INodePacket> localPacketQueue, AutoResetEvent localPacketAvailable, AutoResetEvent localTerminatePacketPump)
{
// Ordering of the wait handles is important. The first signalled wait handle in the array
// will be returned by WaitAny if multiple wait handles are signalled. We prefer to have the
// terminate event triggered so that we cannot get into a situation where packets are being
// spammed to the endpoint and it never gets an opportunity to shutdown.
CommunicationsUtilities.Trace("Entering read loop.");
byte[] headerByte = new byte[5];
#if FEATURE_APM
IAsyncResult result = localReadPipe.BeginRead(headerByte, 0, headerByte.Length, null, null);
#else
Task <int> readTask = CommunicationsUtilities.ReadAsync(localReadPipe, headerByte, headerByte.Length);
#endif
bool exitLoop = false;
do
{
// Ordering is important. We want packetAvailable to supercede terminate otherwise we will not properly wait for all
// packets to be sent by other threads which are shutting down, such as the logging thread.
WaitHandle[] handles = new WaitHandle[] {
#if FEATURE_APM
result.AsyncWaitHandle,
#else
((IAsyncResult)readTask).AsyncWaitHandle,
#endif
localPacketAvailable, localTerminatePacketPump
};
int waitId = WaitHandle.WaitAny(handles);
switch (waitId)
{
case 0:
{
int bytesRead = 0;
try
{
#if FEATURE_APM
bytesRead = localReadPipe.EndRead(result);
#else
bytesRead = readTask.Result;
#endif
}
catch (Exception e)
{
// Lost communications. Abort (but allow node reuse)
CommunicationsUtilities.Trace("Exception reading from server. {0}", e);
ExceptionHandling.DumpExceptionToFile(e);
ChangeLinkStatus(LinkStatus.Inactive);
exitLoop = true;
break;
}
if (bytesRead != headerByte.Length)
{
// Incomplete read. Abort.
if (bytesRead == 0)
{
CommunicationsUtilities.Trace("Parent disconnected abruptly");
}
else
{
CommunicationsUtilities.Trace("Incomplete header read from server. {0} of {1} bytes read", bytesRead, headerByte.Length);
}
ChangeLinkStatus(LinkStatus.Failed);
exitLoop = true;
break;
}
NodePacketType packetType = (NodePacketType)Enum.ToObject(typeof(NodePacketType), headerByte[0]);
try
{
_packetFactory.DeserializeAndRoutePacket(0, packetType, BinaryTranslator.GetReadTranslator(localReadPipe, _sharedReadBuffer));
}
catch (Exception e)
{
// Error while deserializing or handling packet. Abort.
CommunicationsUtilities.Trace("Exception while deserializing packet {0}: {1}", packetType, e);
ExceptionHandling.DumpExceptionToFile(e);
ChangeLinkStatus(LinkStatus.Failed);
exitLoop = true;
break;
}
#if FEATURE_APM
result = localReadPipe.BeginRead(headerByte, 0, headerByte.Length, null, null);
#else
readTask = CommunicationsUtilities.ReadAsync(localReadPipe, headerByte, headerByte.Length);
#endif
}
break;
case 1:
case 2:
try
{
// Write out all the queued packets.
INodePacket packet;
while (localPacketQueue.TryDequeue(out packet))
{
MemoryStream packetStream = new MemoryStream();
ITranslator writeTranslator = BinaryTranslator.GetWriteTranslator(packetStream);
packetStream.WriteByte((byte)packet.Type);
// Pad for packet length
packetStream.Write(BitConverter.GetBytes((int)0), 0, 4);
// Reset the position in the write buffer.
packet.Translate(writeTranslator);
// Now write in the actual packet length
packetStream.Position = 1;
packetStream.Write(BitConverter.GetBytes((int)packetStream.Length - 5), 0, 4);
localWritePipe.Write(packetStream.GetBuffer(), 0, (int)packetStream.Length);
}
}
catch (Exception e)
{
// Error while deserializing or handling packet. Abort.
CommunicationsUtilities.Trace("Exception while serializing packets: {0}", e);
ExceptionHandling.DumpExceptionToFile(e);
ChangeLinkStatus(LinkStatus.Failed);
exitLoop = true;
break;
}
if (waitId == 2)
{
CommunicationsUtilities.Trace("Disconnecting voluntarily");
ChangeLinkStatus(LinkStatus.Failed);
exitLoop = true;
}
break;
default:
ErrorUtilities.ThrowInternalError("waitId {0} out of range.", waitId);
break;
}
}while (!exitLoop);
}