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// Copyright Epic Games, Inc. All Rights Reserved.
#include "hordecomputesocket.h"
#include <zencore/logging.h>
namespace zen::horde {
ComputeSocket::ComputeSocket(std::unique_ptr<ComputeTransport> Transport)
: m_Log(zen::logging::Get("horde.socket"))
, m_Transport(std::move(Transport))
{
}
ComputeSocket::~ComputeSocket()
{
// Shutdown order matters: first stop the ping thread, then unblock send threads
// by detaching readers, then join send threads, and finally close the transport
// to unblock the recv thread (which is blocked on RecvMessage).
{
std::lock_guard<std::mutex> Lock(m_PingMutex);
m_PingShouldStop = true;
m_PingCV.notify_all();
}
for (auto& Reader : m_Readers)
{
Reader.Detach();
}
for (auto& [Id, Thread] : m_SendThreads)
{
if (Thread.joinable())
{
Thread.join();
}
}
m_Transport->Close();
if (m_RecvThread.joinable())
{
m_RecvThread.join();
}
if (m_PingThread.joinable())
{
m_PingThread.join();
}
}
Ref<ComputeChannel>
ComputeSocket::CreateChannel(int ChannelId)
{
ComputeBuffer::Params Params;
ComputeBuffer RecvBuffer;
if (!RecvBuffer.CreateNew(Params))
{
return {};
}
ComputeBuffer SendBuffer;
if (!SendBuffer.CreateNew(Params))
{
return {};
}
Ref<ComputeChannel> Channel(new ComputeChannel(RecvBuffer.CreateReader(), SendBuffer.CreateWriter()));
// Attach recv buffer writer (transport recv thread writes into this)
{
std::lock_guard<std::mutex> Lock(m_WritersMutex);
m_Writers.emplace(ChannelId, RecvBuffer.CreateWriter());
}
// Attach send buffer reader (send thread reads from this)
{
ComputeBufferReader Reader = SendBuffer.CreateReader();
m_Readers.push_back(Reader);
m_SendThreads.emplace(ChannelId, std::thread(&ComputeSocket::SendThreadProc, this, ChannelId, std::move(Reader)));
}
return Channel;
}
void
ComputeSocket::StartCommunication()
{
m_RecvThread = std::thread(&ComputeSocket::RecvThreadProc, this);
m_PingThread = std::thread(&ComputeSocket::PingThreadProc, this);
}
void
ComputeSocket::PingThreadProc()
{
while (true)
{
{
std::unique_lock<std::mutex> Lock(m_PingMutex);
if (m_PingCV.wait_for(Lock, std::chrono::milliseconds(2000), [this] { return m_PingShouldStop; }))
{
break;
}
}
std::lock_guard<std::mutex> Lock(m_SendMutex);
FrameHeader Header;
Header.Channel = 0;
Header.Size = ControlPing;
m_Transport->SendMessage(&Header, sizeof(Header));
}
}
void
ComputeSocket::RecvThreadProc()
{
// Writers are cached locally to avoid taking m_WritersMutex on every frame.
// The shared m_Writers map is only accessed when a channel is seen for the first time.
std::unordered_map<int, ComputeBufferWriter> CachedWriters;
FrameHeader Header;
while (m_Transport->RecvMessage(&Header, sizeof(Header)))
{
if (Header.Size >= 0)
{
// Data frame
auto It = CachedWriters.find(Header.Channel);
if (It == CachedWriters.end())
{
std::lock_guard<std::mutex> Lock(m_WritersMutex);
auto WIt = m_Writers.find(Header.Channel);
if (WIt == m_Writers.end())
{
ZEN_WARN("recv frame for unknown channel {}", Header.Channel);
// Skip the data
std::vector<uint8_t> Discard(Header.Size);
m_Transport->RecvMessage(Discard.data(), Header.Size);
continue;
}
It = CachedWriters.emplace(Header.Channel, WIt->second).first;
}
ComputeBufferWriter& Writer = It->second;
uint8_t* Dest = Writer.WaitToWrite(Header.Size);
if (!Dest || !m_Transport->RecvMessage(Dest, Header.Size))
{
ZEN_WARN("failed to read frame data (channel={}, size={})", Header.Channel, Header.Size);
return;
}
Writer.AdvanceWritePosition(Header.Size);
}
else if (Header.Size == ControlDetach)
{
// Detach the recv buffer for this channel
CachedWriters.erase(Header.Channel);
std::lock_guard<std::mutex> Lock(m_WritersMutex);
auto It = m_Writers.find(Header.Channel);
if (It != m_Writers.end())
{
It->second.MarkComplete();
m_Writers.erase(It);
}
}
else if (Header.Size == ControlPing)
{
// Ping response - ignore
}
else
{
ZEN_WARN("invalid frame header size: {}", Header.Size);
return;
}
}
}
void
ComputeSocket::SendThreadProc(int Channel, ComputeBufferReader Reader)
{
// Each channel has its own send thread. All send threads share m_SendMutex
// to serialize writes to the transport, since TCP requires atomic frame writes.
FrameHeader Header;
Header.Channel = Channel;
const uint8_t* Data;
while ((Data = Reader.WaitToRead(1)) != nullptr)
{
std::lock_guard<std::mutex> Lock(m_SendMutex);
Header.Size = static_cast<int32_t>(Reader.GetMaxReadSize());
m_Transport->SendMessage(&Header, sizeof(Header));
m_Transport->SendMessage(Data, Header.Size);
Reader.AdvanceReadPosition(Header.Size);
}
if (Reader.IsComplete())
{
std::lock_guard<std::mutex> Lock(m_SendMutex);
Header.Size = ControlDetach;
m_Transport->SendMessage(&Header, sizeof(Header));
}
}
} // namespace zen::horde
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