Add callback handle for camera connection / disconnection and unique name getter

README.md

@@ -65,10 +65,13 @@ code into a separate DLL, and now I present to you the ESCAPI:
 - setupESCAPI - Initialize the whole library. (in escapi.cpp)
 - countCaptureDevices - Request number of capture devices available.
 - getCaptureDeviceName - Request the printable name of a capture device.
+- getCaptureDeviceUniqueName - Request the unique name of a capture device.
 - initCapture - Tries to open the video capture device. Returns 0 on failure, 1 on success.
 - doCapture - Requests a video frame to be captured.
 - isCaptureDone - Returns 1 when the requested frame has been captured.
 - deinitCapture - Closes the video capture device.
+- registerForDeviceNotification - Start handle camera connect/disconnect and calling callback for this events.
+- unregisterForDeviceNotification - Stop handle camera connect/disconnect.
 
 So basically, you call setup to initialize the library,
 call init to start the capture device, and call doCapture to 

common/escapi.cpp

@@ -7,13 +7,16 @@ deinitCaptureProc deinitCapture;
 doCaptureProc doCapture;
 isCaptureDoneProc isCaptureDone;
 getCaptureDeviceNameProc getCaptureDeviceName;
+getCaptureDeviceUniqueNameProc getCaptureDeviceUniqueName;
 ESCAPIVersionProc ESCAPIVersion;
 getCapturePropertyValueProc getCapturePropertyValue;
 getCapturePropertyAutoProc getCapturePropertyAuto;
 setCapturePropertyProc setCaptureProperty;
 getCaptureErrorLineProc getCaptureErrorLine;
 getCaptureErrorCodeProc getCaptureErrorCode;
 initCaptureWithOptionsProc initCaptureWithOptions;
+registerForDeviceNotificationProc registerForDeviceNotification;
+unregisterForDeviceNotificationProc unregisterForDeviceNotification;
 
 
 /* Internal: initialize COM */
@@ -35,19 +38,23 @@ int setupESCAPI()
   isCaptureDone = (isCaptureDoneProc)GetProcAddress(capdll, "isCaptureDone");
   initCOM = (initCOMProc)GetProcAddress(capdll, "initCOM");
   getCaptureDeviceName = (getCaptureDeviceNameProc)GetProcAddress(capdll, "getCaptureDeviceName");
+  getCaptureDeviceUniqueName = (getCaptureDeviceUniqueNameProc)GetProcAddress(capdll, "getCaptureDeviceUniqueName");
   ESCAPIVersion = (ESCAPIVersionProc)GetProcAddress(capdll, "ESCAPIVersion");
   getCapturePropertyValue = (getCapturePropertyValueProc)GetProcAddress(capdll, "getCapturePropertyValue");
   getCapturePropertyAuto = (getCapturePropertyAutoProc)GetProcAddress(capdll, "getCapturePropertyAuto");
   setCaptureProperty = (setCapturePropertyProc)GetProcAddress(capdll, "setCaptureProperty");
   getCaptureErrorLine = (getCaptureErrorLineProc)GetProcAddress(capdll, "getCaptureErrorLine");
   getCaptureErrorCode = (getCaptureErrorCodeProc)GetProcAddress(capdll, "getCaptureErrorCode");
   initCaptureWithOptions = (initCaptureWithOptionsProc)GetProcAddress(capdll, "initCaptureWithOptions");
+  registerForDeviceNotification = (registerForDeviceNotificationProc)GetProcAddress(capdll, "registerForDeviceNotification");
+  unregisterForDeviceNotification = (unregisterForDeviceNotificationProc)GetProcAddress(capdll, "unregisterForDeviceNotification");
 
 
   /* Check that we got all the entry points */
   if (initCOM == NULL ||
       ESCAPIVersion == NULL ||
       getCaptureDeviceName == NULL ||
+      getCaptureDeviceUniqueName == NULL ||
       countCaptureDevices == NULL ||
       initCapture == NULL ||
       deinitCapture == NULL ||
@@ -58,7 +65,9 @@ int setupESCAPI()
 	  setCaptureProperty == NULL ||
 	  getCaptureErrorLine == NULL ||
 	  getCaptureErrorCode == NULL ||
-	  initCaptureWithOptions == NULL)
+	  initCaptureWithOptions == NULL ||
+	  registerForDeviceNotification == NULL ||
+	  unregisterForDeviceNotification == NULL)
       return 0;
 
   /* Verify DLL version is at least what we want */

common/escapi.h

@@ -1,4 +1,5 @@
 /* Extremely Simple Capture API */
+#include <functional>
 
 struct SimpleCapParams
 {
@@ -62,6 +63,9 @@ typedef int (*isCaptureDoneProc)(unsigned int deviceno);
 /* Get the user-friendly name of a capture device. */
 typedef void (*getCaptureDeviceNameProc)(unsigned int deviceno, char *namebuffer, int bufferlength);
 
+/* Get the unique name of a capture device. */
+typedef void(*getCaptureDeviceUniqueNameProc)(unsigned int deviceno, char *namebuffer, int bufferlength);
+
 /* Returns the ESCAPI DLL version. 0x200 for 2.0 */
 typedef int (*ESCAPIVersionProc)();
 
@@ -92,10 +96,14 @@ typedef int (*getCaptureErrorLineProc)(unsigned int deviceno);
 /* Return HRESULT of the catastrophic error, or 0 if none. */
 typedef int (*getCaptureErrorCodeProc)(unsigned int deviceno);
 
-/* initCaptureWithOptions allows additional options to be given. Otherwise it's identical with initCapture
-*/
+/* initCaptureWithOptions allows additional options to be given. Otherwise it's identical with initCapture */
 typedef int (*initCaptureWithOptionsProc)(unsigned int deviceno, struct SimpleCapParams *aParams, unsigned int aOptions);
 
+/* Start handle camera connect/disconnect and calling callback for this events. */
+typedef void(*registerForDeviceNotificationProc)(std::function<void(bool isArrival)> callback);
+/* Stop handle camera connect/disconnect. */
+typedef void(*unregisterForDeviceNotificationProc)();
+
 // Options accepted by above:
 // Return raw data instead of converted rgb. Using this option assumes you know what you're doing.
 #define CAPTURE_OPTION_RAWDATA 1 
@@ -110,11 +118,14 @@ extern deinitCaptureProc deinitCapture;
 extern doCaptureProc doCapture;
 extern isCaptureDoneProc isCaptureDone;
 extern getCaptureDeviceNameProc getCaptureDeviceName;
+extern getCaptureDeviceUniqueNameProc getCaptureDeviceUniqueName;
 extern ESCAPIVersionProc ESCAPIVersion;
 extern getCapturePropertyValueProc getCapturePropertyValue;
 extern getCapturePropertyAutoProc getCapturePropertyAuto;
 extern setCapturePropertyProc setCaptureProperty;
 extern getCaptureErrorLineProc getCaptureErrorLine;
 extern getCaptureErrorCodeProc getCaptureErrorCode;
 extern initCaptureWithOptionsProc initCaptureWithOptions;
+extern registerForDeviceNotificationProc registerForDeviceNotification;
+extern unregisterForDeviceNotificationProc unregisterForDeviceNotification;
 #endif

escapi_dll/cameraeventshandler.cpp

@@ -0,0 +1,114 @@
+#include "cameraeventshandler.h"
+#include <thread>
+
+HDEVNOTIFY  gDeviceNotify = NULL;
+std::thread gMsgLoop;
+BOOL gIsWorking;
+HWND gHwnd;
+bool gIsAccept;
+std::function<void(bool isArrival)> gCallback;
+
+void CreateMessageOnlyWindow()
+{
+	static LPCWSTR class_name = (LPCWSTR)"HANDLER_CLASS";
+	WNDCLASSEX wx = {};
+	wx.cbSize = sizeof(WNDCLASSEX);
+	wx.lpfnWndProc = WndProc;    
+	wx.hInstance = NULL;
+	wx.lpszClassName = class_name;
+
+	if (RegisterClassEx(&wx))
+	{
+		gHwnd = CreateWindowEx(0, class_name, (LPCWSTR)"handler", 0, 0, 0, 0, 0, HWND_MESSAGE, NULL, NULL, NULL);
+	}
+
+	DEV_BROADCAST_DEVICEINTERFACE di = { 0 };
+	di.dbcc_size = sizeof(di);
+	di.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
+	di.dbcc_classguid = KSCATEGORY_CAPTURE;
+
+	gDeviceNotify = RegisterDeviceNotification(
+		gHwnd,
+		&di,
+		DEVICE_NOTIFY_WINDOW_HANDLE
+	);
+
+	MSG msg;
+	BOOL bRet;
+
+	while (gIsWorking)
+	{
+		bRet = GetMessage(&msg, NULL, 0, 0);
+		if (bRet == -1)
+		{
+			PostQuitMessage(0);
+			break;
+		}
+		else
+		{
+			TranslateMessage(&msg);
+			DispatchMessage(&msg);
+		}
+	}
+}
+
+LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
+{
+	switch (msg)
+	{
+	case WM_DEVICECHANGE:
+	{
+		if (lParam != 0)
+		{
+			// call only once for device connection / disconnection event
+			// https://stackoverflow.com/questions/44183743/wm-devicechange-comes-twice-when-disconnecting-connecting-device
+			gIsAccept = !gIsAccept;
+			if (gIsAccept)
+			{
+				switch (wParam)
+				{
+				case DBT_DEVICEARRIVAL:
+					gCallback(true);
+					break;
+				case DBT_DEVICEREMOVECOMPLETE:
+					gCallback(false);
+					break;
+				default:
+					// don't need to handle other wParams
+					break;
+				}
+			}
+		}
+		break;
+	}
+	case WM_CLOSE:
+		DestroyWindow(hwnd);
+		break;
+	case WM_DESTROY:
+		PostQuitMessage(0);
+		break;
+	default:
+		return DefWindowProc(hwnd, msg, wParam, lParam);
+	}
+
+	return 0;
+}
+
+void RegisterForDeviceNotificationFromInterface(const std::function<void(bool isArrival)>& callback)
+{
+	gCallback = callback;
+	gIsWorking = true;
+	gMsgLoop = std::thread(&CreateMessageOnlyWindow);
+}
+
+void UnregisterForDeviceNotificationFromInterface()
+{
+	if (gDeviceNotify)
+		UnregisterDeviceNotification(gDeviceNotify);
+
+	gIsWorking = false;
+	PostMessage(gHwnd, WM_CLOSE, 0, 0);
+
+	if (gMsgLoop.joinable())
+		gMsgLoop.join();
+}

escapi_dll/cameraeventshandler.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <Windows.h>
+#include <Dbt.h>
+#include <ks.h>
+#include <ksmedia.h>
+#include <functional> 
+
+#include <Mfidl.h>
+
+LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
+void RegisterForDeviceNotificationFromInterface(const std::function<void(bool isArrival)>& callback);
+void UnregisterForDeviceNotificationFromInterface();

escapi_dll/escapi_dll.cpp

@@ -2,6 +2,9 @@
 #define ESCAPI_DEFINITIONS_ONLY
 #include "escapi.h"
 
+#include <Dbt.h>
+#include <ks.h>
+#include <ksmedia.h>
 
 #define MAXDEVICES 16
 
@@ -13,12 +16,15 @@ extern HRESULT InitDevice(int device);
 extern void CleanupDevice(int device);
 extern int CountCaptureDevices();
 extern void GetCaptureDeviceName(int deviceno, char * namebuffer, int bufferlength);
+extern void GetCaptureDeviceSymbolicLink(int deviceno, char * namebuffer, int bufferlength);
 extern void CheckForFail(int device);
 extern int GetErrorCode(int device);
 extern int GetErrorLine(int device);
 extern float GetProperty(int device, int prop);
 extern int GetPropertyAuto(int device, int prop);
 extern int SetProperty(int device, int prop, float value, int autoval);
+extern void RegisterForDeviceNotification(const std::function<void(bool isArrival)>& callback);
+extern void UnregisterForDeviceNotification();
 
 BOOL APIENTRY DllMain(HANDLE hModule,
 	DWORD  ul_reason_for_call,
@@ -37,6 +43,14 @@ extern "C" void __declspec(dllexport) getCaptureDeviceName(unsigned int deviceno
 	GetCaptureDeviceName(deviceno, namebuffer, bufferlength);
 }
 
+extern "C" void __declspec(dllexport) getCaptureDeviceUniqueName(unsigned int deviceno, char *namebuffer, int bufferlength)
+{
+	if (deviceno > MAXDEVICES)
+		return;
+
+	GetCaptureDeviceSymbolicLink(deviceno, namebuffer, bufferlength);
+}
+
 extern "C" int __declspec(dllexport) ESCAPIDLLVersion()
 {
 	return 0x200; // due to mess up, earlier programs check for exact version; this needs to stay constant
@@ -78,6 +92,16 @@ extern "C" void __declspec(dllexport) deinitCapture(unsigned int deviceno)
 	CleanupDevice(deviceno);
 }
 
+extern "C" void __declspec(dllexport) registerForDeviceNotification(std::function<void(bool isArrival)> callback)
+{
+	RegisterForDeviceNotification(callback);
+}
+
+extern "C" void __declspec(dllexport) unregisterForDeviceNotification()
+{
+	UnregisterForDeviceNotification();
+}
+
 extern "C" void __declspec(dllexport) doCapture(unsigned int deviceno)
 {
 	if (deviceno > MAXDEVICES)

escapi_dll/escapi_dll.vcxproj

@@ -158,6 +158,7 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="cameraeventshandler.cpp" />
     <ClCompile Include="capture.cpp" />
     <ClCompile Include="conversion.cpp" />
     <ClCompile Include="escapi_dll.cpp" />

escapi_dll/interface.cpp

@@ -9,6 +9,7 @@
 #include "capture.h"
 #include "scopedrelease.h"
 #include "choosedeviceparam.h"
+#include "cameraeventshandler.h"
 
 #define MAXDEVICES 16
 
@@ -27,6 +28,7 @@ void CleanupDevice(int aDevice)
 		gDevice[aDevice] = 0;
 	}
 }
+
 HRESULT InitDevice(int aDevice)
 {
 	if (gDevice[aDevice])
@@ -43,8 +45,6 @@ HRESULT InitDevice(int aDevice)
 	return hr;
 }
 
-
-
 int CountCaptureDevices()
 {
 	HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE);
@@ -76,7 +76,7 @@ int CountCaptureDevices()
 	return param.mCount;
 }
 
-void GetCaptureDeviceName(int aDevice, char * aNamebuffer, int aBufferlength)
+void GetCaptureName(int aDevice, char * aNamebuffer, int aBufferlength, REFGUID guidKey)
 {
 	int i;
 	if (!aNamebuffer || aBufferlength <= 0)
@@ -116,7 +116,7 @@ void GetCaptureDeviceName(int aDevice, char * aNamebuffer, int aBufferlength)
 		WCHAR *name = 0;
 		UINT32 namelen = 255;
 		hr = param.mDevices[aDevice]->GetAllocatedString(
-			MF_DEVSOURCE_ATTRIBUTE_FRIENDLY_NAME,
+			guidKey,
 			&name,
 			&namelen
 			);
@@ -135,6 +135,16 @@ void GetCaptureDeviceName(int aDevice, char * aNamebuffer, int aBufferlength)
 	}
 }
 
+void GetCaptureDeviceName(int aDevice, char * aNamebuffer, int aBufferlength)
+{
+	GetCaptureName(aDevice, aNamebuffer, aBufferlength, MF_DEVSOURCE_ATTRIBUTE_FRIENDLY_NAME);
+}
+
+void GetCaptureDeviceSymbolicLink(int aDevice, char * aNamebuffer, int aBufferlength)
+{
+	GetCaptureName(aDevice, aNamebuffer, aBufferlength, MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_SYMBOLIC_LINK);
+}
+
 void CheckForFail(int aDevice)
 {
 	if (!gDevice[aDevice])
@@ -198,3 +208,13 @@ int SetProperty(int aDevice, int aProp, float aValue, int aAutoval)
 		return 0;
 	return gDevice[aDevice]->setProperty(aProp, aValue, aAutoval);
 }
+
+void RegisterForDeviceNotification(const std::function<void(bool isArrival)>& callback)
+{
+	RegisterForDeviceNotificationFromInterface(callback);
+}
+
+void UnregisterForDeviceNotification()
+{
+	UnregisterForDeviceNotificationFromInterface();
+}