/// <summary>
/// Reads the header from the buffer, using previous
/// </summary>
private FrameHeader ReadHeader(byte[] buffer, ref int offset, int length, int headerLength,
ProtocolVersion version)
{
if (offset == 0)
{
var previousHeaderBuffer = Interlocked.Exchange(ref _minHeaderBuffer, null);
if (previousHeaderBuffer != null)
{
if (previousHeaderBuffer.Length + length < headerLength)
{
// Unlikely scenario where there were a few bytes for a header buffer and the new bytes are
// not enough to complete the header
Volatile.Write(ref _minHeaderBuffer,
Utils.JoinBuffers(previousHeaderBuffer, 0, previousHeaderBuffer.Length, buffer, 0, length));
return(null);
}
offset += headerLength - previousHeaderBuffer.Length;
// Use the previous and the current buffer to build the header
return(FrameHeader.ParseResponseHeader(version, previousHeaderBuffer, buffer));
}
}
if (length - offset < headerLength)
{
// There aren't enough bytes in the current buffer to read the header, store it for later
Volatile.Write(ref _minHeaderBuffer, Utils.SliceBuffer(buffer, offset, length - offset));
return(null);
}
// The header is contained in the current buffer
var header = FrameHeader.ParseResponseHeader(version, buffer, offset);
offset += headerLength;
return(header);
}
public override void Write(byte[] buffer, int offset, int count)
{
if (KeepReferences && offset == 0 && count == buffer.Length)
{
//Keep the reference to the original buffer
Buffers.Add(buffer);
}
else
{
Buffers.Add(Utils.SliceBuffer(buffer, offset, count));
}
TotalLength += count;
this._position = TotalLength;
}
/// <summary>
/// Parses the first 8 or 9 bytes and returns a FrameHeader
/// </summary>
public static FrameHeader ParseResponseHeader(ProtocolVersion version, byte[] buffer, int offset)
{
var header = new FrameHeader()
{
_versionByte = buffer[offset++],
Flags = (HeaderFlag)buffer[offset++]
};
if (!version.Uses2BytesStreamIds())
{
//Stream id is a signed byte in v1 and v2 of the protocol
header.StreamId = (sbyte)buffer[offset++];
}
else
{
header.StreamId = BeConverter.ToInt16(buffer, offset);
offset += 2;
}
header.Opcode = buffer[offset++];
header.BodyLength = BeConverter.ToInt32(Utils.SliceBuffer(buffer, offset, 4));
return(header);
}
/// <summary>
/// Parses the bytes received into a frame. Uses the internal operation state to do the callbacks.
/// Returns true if a full operation (streamId) has been processed and there is one available.
/// </summary>
/// <param name="buffer">Byte buffer to read</param>
/// <param name="offset">Offset within the buffer</param>
/// <param name="count">Length of bytes to be read from the buffer</param>
/// <returns>True if a full operation (streamId) has been processed.</returns>
protected virtual bool ReadParse(byte[] buffer, int offset, int count)
{
var state = _receivingOperation;
if (state == null)
{
if (_minimalBuffer != null)
{
buffer = Utils.JoinBuffers(_minimalBuffer, 0, _minimalBuffer.Length, buffer, offset, count);
offset = 0;
count = buffer.Length;
}
var headerSize = FrameHeader.GetSize(ProtocolVersion);
if (count < headerSize)
{
//There is not enough data to read the header
_minimalBuffer = Utils.SliceBuffer(buffer, offset, count);
return(false);
}
_minimalBuffer = null;
var header = FrameHeader.ParseResponseHeader(ProtocolVersion, buffer, offset);
if (!header.IsValidResponse())
{
_logger.Error("Not a response header");
}
offset += headerSize;
count -= headerSize;
if (header.Opcode != EventResponse.OpCode)
{
//Its a response to a previous request
state = _pendingOperations[header.StreamId];
}
else
{
//Its an event
state = new OperationState
{
Callback = EventHandler
};
}
state.Header = header;
_receivingOperation = state;
}
var countAdded = state.AppendBody(buffer, offset, count);
if (!state.IsBodyComplete)
{
//Nothing finished
return(false);
}
_logger.Verbose("Read #{0} for Opcode {1} from host {2}", state.Header.StreamId, state.Header.Opcode, Address);
//Stop reference it as the current receiving operation
_receivingOperation = null;
if (state.Header.Opcode != EventResponse.OpCode)
{
//Remove from pending
_pendingOperations.TryRemove(state.Header.StreamId, out state);
//Release the streamId
_freeOperations.Push(state.Header.StreamId);
}
try
{
var response = ReadParseResponse(state.Header, state.BodyStream);
state.InvokeCallback(null, response);
}
catch (Exception ex)
{
state.InvokeCallback(ex);
}
if (countAdded < count)
{
//There is more data, from the next frame
ReadParse(buffer, offset + countAdded, count - countAdded);
}
return(true);
//There isn't enough data to read the whole frame.
//It is already buffered, carry on.
}
/// <summary>
/// Parses the bytes received into a frame. Uses the internal operation state to do the callbacks.
/// Returns true if a full operation (streamId) has been processed and there is one available.
/// </summary>
/// <returns>True if a full operation (streamId) has been processed.</returns>
internal bool ReadParse(byte[] buffer, int length)
{
if (length <= 0)
{
return(false);
}
byte protocolVersion;
if (_frameHeaderSize == 0)
{
//The server replies the first message with the max protocol version supported
protocolVersion = FrameHeader.GetProtocolVersion(buffer);
_serializer.ProtocolVersion = protocolVersion;
_frameHeaderSize = FrameHeader.GetSize(protocolVersion);
}
else
{
protocolVersion = _serializer.ProtocolVersion;
}
//Use _readStream to buffer between messages, under low pressure, it should be null most of the times
var stream = Interlocked.Exchange(ref _readStream, null);
var operationCallbacks = new LinkedList <Action <MemoryStream> >();
var offset = 0;
if (_minimalBuffer != null)
{
//use a negative offset to identify that there is a previous header buffer
offset = -1 * _minimalBuffer.Length;
}
while (offset < length)
{
FrameHeader header;
//The remaining body length to read from this buffer
int remainingBodyLength;
if (_receivingHeader == null)
{
if (length - offset < _frameHeaderSize)
{
_minimalBuffer = offset >= 0 ?
Utils.SliceBuffer(buffer, offset, length - offset) :
//it should almost never be the case there isn't enough bytes to read the header more than once
// ReSharper disable once PossibleNullReferenceException
Utils.JoinBuffers(_minimalBuffer, 0, _minimalBuffer.Length, buffer, 0, length);
break;
}
if (offset >= 0)
{
header = FrameHeader.ParseResponseHeader(protocolVersion, buffer, offset);
}
else
{
header = FrameHeader.ParseResponseHeader(protocolVersion, _minimalBuffer, buffer);
_minimalBuffer = null;
}
Logger.Verbose("Received #{0} from {1}", header.StreamId, Address);
offset += _frameHeaderSize;
remainingBodyLength = header.BodyLength;
}
else
{
header = _receivingHeader;
remainingBodyLength = header.BodyLength - (int)stream.Length;
_receivingHeader = null;
}
if (remainingBodyLength > length - offset)
{
//the buffer does not contains the body for this frame, buffer for later
MemoryStream nextMessageStream;
if (operationCallbacks.Count == 0 && stream != null)
{
//There hasn't been any operations completed with this buffer
//And there is a previous stream: reuse it
nextMessageStream = stream;
}
else
{
nextMessageStream = Configuration.BufferPool.GetStream(typeof(Connection) + "/Read");
}
nextMessageStream.Write(buffer, offset, length - offset);
Interlocked.Exchange(ref _readStream, nextMessageStream);
_receivingHeader = header;
break;
}
stream = stream ?? Configuration.BufferPool.GetStream(typeof(Connection) + "/Read");
OperationState state;
if (header.Opcode != EventResponse.OpCode)
{
state = RemoveFromPending(header.StreamId);
}
else
{
//Its an event
state = new OperationState(EventHandler);
}
stream.Write(buffer, offset, remainingBodyLength);
var callback = state.SetCompleted();
operationCallbacks.AddLast(CreateResponseAction(header, callback));
offset += remainingBodyLength;
}
return(InvokeReadCallbacks(stream, operationCallbacks));
}
