[idd] project: organize driver sources by responsibility

Group the IDD sources and Visual Studio filters by subsystem.

Split the device and swap-chain implementations into focused units,
rename the context classes, and reduce header coupling.

idd/LGIdd/display/monitor/Context.h

@@ -0,0 +1,89 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2026 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
+ */
+
+#pragma once
+
+#include <Windows.h>
+#include <wdf.h>
+#include <IddCx.h>
+
+#include <atomic>
+#include <memory>
+#include <mutex>
+
+struct CD3D11Device;
+class CDeviceContext;
+class CSwapChainProcessor;
+
+class CMonitorContext
+{
+private:
+  IDDCX_MONITOR m_monitor;
+
+  // Guards the swap chain and device pointers. Assign and unassign can run
+  // concurrently (an unassign triggered by the worker's WdfObjectDelete can
+  // race the next assign), and shared_ptr copy/reset is not thread safe.
+  SRWLOCK m_lock = SRWLOCK_INIT;
+
+  // IddCx can issue a replacement assignment before an earlier assignment
+  // has finished creating its devices. Serialize those expensive setup paths
+  // while still allowing UnassignSwapChain to cancel the active one.
+  std::mutex m_assignMutex;
+  std::shared_ptr<CD3D11Device> m_dx11Device;
+
+  CDeviceContext * m_devContext;
+  std::unique_ptr<CSwapChainProcessor> m_swapChain;
+
+  // Incremented whenever the current assignment is replaced or unassigned.
+  // Device creation is performed outside m_lock, so this lets an unassign
+  // cancel that work before a processor is started on a stale swap chain.
+  std::atomic<UINT64> m_assignmentGeneration = 0;
+
+  void DetachSwapChain();
+
+public:
+  CMonitorContext(
+    _In_ IDDCX_MONITOR monitor, CDeviceContext * device);
+
+  virtual ~CMonitorContext();
+
+  NTSTATUS AssignSwapChain(
+    IDDCX_SWAPCHAIN swapChain, LUID renderAdapter, HANDLE newFrameEvent);
+  void UnassignSwapChain();
+  bool IsAssignmentCurrent(UINT64 generation) const
+  {
+    return m_assignmentGeneration.load(std::memory_order_acquire) == generation;
+  }
+
+  CDeviceContext * GetDeviceContext() { return m_devContext; }
+};
+
+struct CMonitorContextWrapper
+{
+  CMonitorContext * context;
+
+  void Cleanup()
+  {
+    delete context;
+    context = nullptr;
+  }
+};
+
+WDF_DECLARE_CONTEXT_TYPE(CMonitorContextWrapper);