[idd] helper: added new helper service

As the IDD itself runs in a WUMDF sandbox, it doesn't have enough
access to perform interactive operations such as moving the cursor.

This helper service communicates with the IDD over a named pipe,
so that we can perform these things, as well as in the future provide
a configuration GUI.

idd/LGIdd/CPipeServer.cpp

@@ -0,0 +1,163 @@
+/**
+ * Looking Glass
+ * Copyright <20> 2017-2025 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "CPipeServer.h"
+#include "CDebug.h"
+
+CPipeServer g_pipe;
+
+bool CPipeServer::Init()
+{
+  _DeInit();
+
+  m_pipe.Attach(CreateNamedPipeA(
+    LG_PIPE_NAME,
+    PIPE_ACCESS_DUPLEX,
+    PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT,
+    1,
+    1024,
+    1024,
+    0,
+    NULL));
+
+  if (!m_pipe.IsValid())
+  {
+    DEBUG_ERROR_HR(GetLastError(), "Failed to create the named pipe");
+    return false;
+  }
+
+  m_running = true;
+  m_thread.Attach(CreateThread(
+    NULL,
+    0,
+    _pipeThread,
+    (LPVOID)this,
+    0,
+    NULL));
+
+  if (!m_thread.IsValid())
+  {
+    DEBUG_ERROR_HR(GetLastError(), "Failed to create the pipe thread");
+    return false;
+  }
+
+  DEBUG_TRACE("Pipe Initialized");
+  return true;
+}
+
+void CPipeServer::_DeInit()
+{
+  m_running = false;
+  m_connected = false;
+
+  if (m_thread.IsValid())
+  {
+    CancelSynchronousIo(m_thread.Get());
+    WaitForSingleObject(m_thread.Get(), INFINITE);
+    m_thread.Close();
+  }
+
+  if (m_pipe.IsValid())
+  {
+    FlushFileBuffers(m_pipe.Get());
+    m_pipe.Close();
+  }
+}
+
+void CPipeServer::DeInit()
+{  
+  DEBUG_TRACE("Pipe Stopping");
+  _DeInit();
+  DEBUG_TRACE("Pipe Stopped");
+}
+
+void CPipeServer::Thread()
+{
+  DEBUG_TRACE("Pipe thread started");
+  while(m_running)
+  {
+    m_connected = false;
+    bool result = ConnectNamedPipe(m_pipe.Get(), NULL);
+    DWORD err = GetLastError();
+    if (!result && err != ERROR_PIPE_CONNECTED)
+    {
+      // if graceful shutdown
+      if ((err == ERROR_OPERATION_ABORTED && !m_running) ||
+          err == ERROR_NO_DATA)
+        break;
+
+      // if timeout
+      if (err == ERROR_SEM_TIMEOUT)
+        continue;
+
+      DEBUG_FATAL_HR(err, "Error connecting to the named pipe");
+      break;
+    }
+
+    DEBUG_TRACE("Client connected");
+
+    m_connected = true;
+    while (m_running && m_connected)
+    {
+      //TODO: Read messages from the client
+      Sleep(1000);
+    }
+
+    DEBUG_TRACE("Client disconnected");
+    DisconnectNamedPipe(m_pipe.Get());
+  }
+
+  m_running   = false;
+  m_connected = false;
+  DEBUG_TRACE("Pipe thread shutdown");
+}
+
+void CPipeServer::WriteMsg(LGPipeMsg & msg)
+{
+  DWORD written;
+  if (!WriteFile(m_pipe.Get(), &msg, sizeof(msg), &written, NULL))
+  {
+    DWORD err = GetLastError();
+    if (err == ERROR_BROKEN_PIPE || err == ERROR_NO_DATA)
+    {
+      DEBUG_WARN_HR(err, "Client disconnected, failed to write");
+      m_connected = false;
+      return;
+    }
+
+    DEBUG_WARN_HR(err, "WriteFile failed on the pipe");
+    return;
+  }
+
+  FlushFileBuffers(m_pipe.Get());
+}
+
+void CPipeServer::SetCursorPos(uint32_t x, uint32_t y)
+{
+  if (!m_connected)
+    return;
+
+  LGPipeMsg msg;
+  msg.size       = sizeof(msg);
+  msg.type       = LGPipeMsg::SETCURSORPOS;
+  msg.curorPos.x = x;
+  msg.curorPos.y = y;
+  WriteMsg(msg);
+}