force shutdown on existing device while DLL unload

XenethCamera.cpp

@@ -8,7 +8,7 @@
 //
 // AUTHOR:        Lutz Rossa
 //
-// COPYRIGHT:     2020 Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
+// COPYRIGHT:     2020-2021 Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
 // LICENSE:       Licensed under the Apache License, Version 2.0 (the "License");
 //                you may not use this file except in compliance with the License.
 //                You may obtain a copy of the License at
@@ -27,6 +27,8 @@
 #include "../../MMDevice/ModuleInterface.h"
 #include <algorithm>
 #include <chrono>
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
 
 const char* g_szCameraName = "XenethCamera";
 const char* g_szExposurePropName = "exposure-property";
@@ -64,6 +66,8 @@ static std::string             g_szLogFile
 ;
 static std::recursive_mutex    g_hLogMutex;
 static std::thread*            g_pLogThread(nullptr);
+std::list<XenethCamera*>       XenethCamera::m_apInstances;
+
 static void LogThreadFunc();
 static std::string LogFormat(const char* szFormat, ...);
 static void LogLine(const char* szFileInfo, std::string && szLine);
@@ -74,6 +78,23 @@ static void LogInit();
 #define STRINGIFY(x) STRINGIFY2(x)
 #define LOG(x) do { LogInit(); std::string szLine(LogFormat x); LogLine(__FILE__ "(" STRINGIFY(__LINE__) "): ", std::move(szLine)); } while (0)
 
+BOOL APIENTRY DllMain(HANDLE /*hModule*/, DWORD ulReasonForCall, LPVOID /*lpReserved*/)
+{
+    switch (ulReasonForCall)
+    {
+        case DLL_PROCESS_ATTACH:
+            break;
+        case DLL_THREAD_ATTACH:
+            break;
+        case DLL_THREAD_DETACH:
+            break;
+        case DLL_PROCESS_DETACH:
+            XenethCamera::DllMainShutdown();
+            break;
+    }
+    return TRUE;
+}
+
 // Exported MMDevice API
 MODULE_API void InitializeModuleData()
 {
@@ -118,6 +139,9 @@ XenethCamera::XenethCamera() :
 	m_uRoiH(0)
 {
     LOG(("XenethCamera::XenethCamera(%p)\n", this));
+    g_hLogMutex.lock();
+    m_apInstances.push_back(this);
+    g_hLogMutex.unlock();
 	// create a property to select the camera
 	XenethCreateProperty("device path", m_szCameraPath.c_str(), MM::String, false, &XenethCamera::OnCameraPath, true);
 
@@ -164,6 +188,9 @@ XenethCamera::~XenethCamera()
     LOG(("XenethCamera::~XenethCamera(%p) m_bInitialized=%d\n", this, m_bInitialized));
     if (m_bInitialized)
 		Shutdown();
+    g_hLogMutex.lock();
+    m_apInstances.remove(this);
+    g_hLogMutex.unlock();
 }
 
 int XenethCamera::XenethCreateProperty(const char* szName, const char* szValue, MM::PropertyType eType,
@@ -679,7 +706,7 @@ int XenethCamera::SnapImage()
     LOG(("XenethCamera::SnapImage(%p) frame count=%u\n", this, XC_GetFrameCount(m_hCamera)));
     int iResult(ConvertXenethResult(XC_GetFrame(m_hCamera, FT_NATIVE, XGF_Blocking,
         static_cast<void*>(m_abyImage.data()), static_cast<int>(m_abyImage.size()))));
-    if (g_iSnapCount < 1000)
+    if (g_iSnapCount < 1000 || iResult != DEVICE_OK)
     {
         ++g_iSnapCount;
         LOG(("XenethCamera::SnapImage(%p) size=%u iResult=%d\n", this, m_abyImage.size(), iResult));
@@ -931,6 +958,16 @@ try_string:
 	return DEVICE_OK;
 }
 
+void XenethCamera::DllMainShutdown()
+{
+    for (auto it = m_apInstances.begin(); it != m_apInstances.end(); ++it)
+    {
+        XenethCamera* p(*it);
+        if (p->m_bInitialized)
+            p->Shutdown();
+    }
+}
+
 double XenethCamera::FromMilliseconds(double dValue, const char* szTargetUnit)
 {
     double dOldValue(dValue);

XenethCamera.h

@@ -63,6 +63,11 @@ public:
 	unsigned GetNumberOfComponents() const;
 	const unsigned int* GetImageBufferAsRGB32();
 
+	/// <summary>
+	/// this function is called before the DLL is unloaded to shut down existing devices
+	/// </summary>
+	static void DllMainShutdown();
+
 private:
 	class XenethProperty
 	{
@@ -89,6 +94,7 @@ private:
 	XCHANDLE                        m_hCamera;
 	std::vector<XenethProperty>     m_aProperties;
 	long                            m_lExposurePropertyIndex;
+	static std::list<XenethCamera*> m_apInstances;
 
 	mutable unsigned m_uRoiX;
 	mutable unsigned m_uRoiY;