HID device connection/disconnection proof-of-concept code.

Author: DJm00n

hidapi/hidapi.h

@@ -178,6 +178,39 @@ extern "C" {
 		*/
 		void  HID_API_EXPORT HID_API_CALL hid_free_enumeration(struct hid_device_info *devs);
 
+		struct hid_callback_token_;
+		typedef struct hid_callback_token_ hid_callback_token; /**< opaque hidapi structure */
+
+		typedef void (*hid_device_callback)(
+			hid_callback_token* callback_token,
+			void* context,
+			struct hid_device_info* dev,
+			int is_connected);
+
+		/** @brief Register HID device notification callback.
+
+			If @p vendor_id is set to 0 then any vendor matches.
+			If @p product_id is set to 0 then any product matches.
+			If @p vendor_id and @p product_id are both set to 0, then
+			all HID devices will be notified.
+
+			@ingroup API
+			@param vendor_id The Vendor ID (VID) of the types of device
+				to notify about.
+			@param product_id The Product ID (PID) of the types of
+				device to notify about.
+			@param context The Context you wanted to provide to
+				your callback function.
+			@param callback The Callback function that will be called
+				on device connection/disconnection.
+
+			@returns
+				This function returns callback token number on success or NULL on failure.
+		*/
+		HID_API_EXPORT hid_callback_token * HID_API_CALL hid_register_callback(unsigned short vendor_id, unsigned short product_id, void* context, hid_device_callback callback);
+
+		int HID_API_EXPORT HID_API_CALL hid_unregister_callback(hid_callback_token* token);
+
 		/** @brief Open a HID device using a Vendor ID (VID), Product ID
 			(PID) and optionally a serial number.
 

hidtest/test.c

@@ -27,6 +27,19 @@
 	#include <unistd.h>
 #endif
 
+void device_callback(
+	hid_callback_token* callback_token,
+	void* context,
+	struct hid_device_info* dev,
+	int is_connected)
+{
+	if (is_connected)
+		printf("New device is connected: %s.\n", dev->path);
+	else
+		printf("Device was disconnected: %s.\n", dev->path);
+
+}
+
 int main(int argc, char* argv[])
 {
 	(void)argc;
@@ -38,6 +51,7 @@ int main(int argc, char* argv[])
 	wchar_t wstr[MAX_STR];
 	hid_device *handle;
 	int i;
+	hid_callback_token *token1, *token2;
 
 	struct hid_device_info *devs, *cur_dev;
 
@@ -67,6 +81,18 @@ int main(int argc, char* argv[])
 	}
 	hid_free_enumeration(devs);
 
+	token1 = hid_register_callback(0, 0, NULL, device_callback);
+	token2 = hid_register_callback(0x054c, 0x0ce6, NULL, device_callback);
+
+	while (1)
+	{
+
+	}
+
+	hid_unregister_callback(token2);
+	hid_unregister_callback(token1);
+
+	/*
 	// Set up the command buffer.
 	memset(buf,0x00,sizeof(buf));
 	buf[0] = 0x01;
@@ -76,7 +102,7 @@ int main(int argc, char* argv[])
 	// Open the device using the VID, PID,
 	// and optionally the Serial number.
 	////handle = hid_open(0x4d8, 0x3f, L"12345");
-	handle = hid_open(0x4d8, 0x3f, NULL);
+	handle = hid_open(0x54c, 0x0ce6, NULL);
 	if (!handle) {
 		printf("unable to open device\n");
  		return 1;
@@ -188,7 +214,7 @@ int main(int argc, char* argv[])
 		printf("%02hhx ", buf[i]);
 	printf("\n");
 
-	hid_close(handle);
+	hid_close(handle);*/
 
 	/* Free static HIDAPI objects. */
 	hid_exit();

windows/hid.c

@@ -46,6 +46,7 @@ typedef LONG NTSTATUS;
 extern "C" {
 #endif
 	#include <setupapi.h>
+	#include <cfgmgr32.h>
 	#include <winioctl.h>
 	#ifdef HIDAPI_USE_DDK
 		#include <hidsdi.h>
@@ -507,6 +508,9 @@ struct hid_device_info HID_API_EXPORT * HID_API_CALL hid_enumerate(unsigned shor
 
 		//wprintf(L"HandleName: %s\n", device_interface_detail_data->DevicePath);
 
+		/* Normalize the path */
+		for (char* p = device_interface_detail_data->DevicePath; *p; ++p) *p = tolower(*p);
+
 		/* Open read-only handle to the device */
 		read_handle = open_device(device_interface_detail_data->DevicePath, FALSE);
 
@@ -573,6 +577,198 @@ void  HID_API_EXPORT HID_API_CALL hid_free_enumeration(struct hid_device_info *d
 	}
 }
 
+struct hid_notify {
+	unsigned short vendor_id;
+	unsigned short product_id;
+	void* context;
+	hid_device_callback callback;
+
+	/** Pointer to the next notification */
+	struct hid_notify* next;
+};
+
+static struct notify_context {
+	HCMNOTIFICATION notify_handle;
+	struct hid_notify* notifys;
+	struct hid_device_info* devs;
+} notify_context = {
+	.notify_handle = NULL,
+	.notifys = NULL,
+	.devs = NULL
+};
+
+DWORD WINAPI interface_notify_callback(HCMNOTIFICATION notify, PVOID context, CM_NOTIFY_ACTION action, PCM_NOTIFY_EVENT_DATA event_data, DWORD event_data_size)
+{
+	switch (action) {
+	case CM_NOTIFY_ACTION_DEVICEINTERFACEARRIVAL:
+	case CM_NOTIFY_ACTION_DEVICEINTERFACEREMOVAL:
+	{
+		char* path;
+		size_t len;
+		struct hid_device_info* dev = NULL;
+		int is_connected = (action == CM_NOTIFY_ACTION_DEVICEINTERFACEARRIVAL) ? TRUE : FALSE;
+
+		len = wcslen(event_data->u.DeviceInterface.SymbolicLink);
+		path = (char*)calloc(len + 1, sizeof(char));
+
+		if (wcstombs(path, event_data->u.DeviceInterface.SymbolicLink, len) == (size_t)-1)
+			goto close;
+
+		/* Normalize the path */
+		for (char* p = path; *p; ++p) *p = tolower(*p);
+
+		if (is_connected) {
+			dev = hid_get_device_info(path);
+
+			/* Append to the end of the device list */
+			if (notify_context.devs) {
+				struct hid_device_info* last = notify_context.devs;
+				while (last->next) {
+					last = last->next;
+				}
+				last->next = dev;
+			}
+			else {
+				notify_context.devs = dev;
+			}
+		}
+		else {
+			/* Remove this device from the device list */
+			for (struct hid_device_info** current = &notify_context.devs; *current; current = &(*current)->next) {
+				if (strcmp((*current)->path, path) == 0) {
+					struct hid_device_info* next = (*current)->next;
+					dev = *current;
+					*current = next;
+					break;
+				}
+			}
+		}
+
+		if (dev) {
+			/* Call the notifications for this device */
+			struct hid_notify* notify = notify_context.notifys;
+			while (notify) {
+				if ((notify->vendor_id == 0x0 || notify->vendor_id == dev->vendor_id) &&
+					(notify->product_id == 0x0 || notify->product_id == dev->product_id)) {
+					/* Call notification callback */
+					(*notify->callback)((hid_callback_token*)notify, notify->context, dev, is_connected);
+				}
+				notify = notify->next;
+			}
+
+			/* Clean removed device info */
+			if (!is_connected)
+				free(dev);
+		}
+
+	close:
+		free(path);
+	}
+	break;
+	}
+
+	return ERROR_SUCCESS;
+}
+
+HID_API_EXPORT hid_callback_token* HID_API_CALL hid_register_callback(unsigned short vendor_id, unsigned short product_id, void* context, hid_device_callback callback)
+{
+	/* Create the record. */
+	struct hid_notify* notify = (struct hid_notify*)calloc(1, sizeof(struct hid_notify));
+
+	/* Fill out the record */
+	notify->next = NULL;
+	notify->vendor_id = vendor_id;
+	notify->product_id = product_id;
+	notify->context = context;
+	notify->callback = callback;
+
+	/* Append to the end */
+	if (notify_context.notifys) {
+		struct hid_notify* last = notify_context.notifys;
+		while (last->next) {
+			last = last->next;
+		}
+		last->next = notify;
+	}
+	else {
+		struct hid_device_info* dev;
+
+		/* Register device connection notification after adding first callback */
+		if (notify_context.notify_handle == NULL) {
+			GUID interface_class_guid;
+			CONFIGRET cr = CR_SUCCESS;
+			CM_NOTIFY_FILTER notify_filter = { 0 };
+
+			HidD_GetHidGuid(&interface_class_guid);
+
+			notify_filter.cbSize = sizeof(notify_filter);
+			notify_filter.FilterType = CM_NOTIFY_FILTER_TYPE_DEVICEINTERFACE;
+			notify_filter.u.DeviceInterface.ClassGuid = interface_class_guid;
+			cr = CM_Register_Notification(&notify_filter, NULL, interface_notify_callback, &notify_context.notify_handle);
+			if (cr != CR_SUCCESS) {
+				return NULL;
+			}
+		}
+
+		notify_context.notifys = notify;
+
+		/* Fill already connected devices */
+		dev = hid_enumerate(0, 0);
+		notify_context.devs = dev;
+
+		/* Notify about already connected devices */
+		while (dev) {
+			if ((notify->vendor_id == 0x0 || notify->vendor_id == dev->vendor_id) &&
+				(notify->product_id == 0x0 || notify->product_id == dev->product_id)) {
+				(*notify->callback)((hid_callback_token*)notify, notify->callback, dev, TRUE);
+			}
+			dev = dev->next;
+		}
+	}
+
+	return (hid_callback_token*)notify;
+}
+
+int HID_API_EXPORT HID_API_CALL hid_unregister_callback(hid_callback_token* token)
+{
+	struct hid_notify* notify = NULL;
+
+	if (token <= 0 || notify_context.notifys == NULL)
+		return 1;
+
+	/* Remove this notification */
+	for (struct hid_notify** current = &notify_context.notifys; *current; current = &(*current)->next) {
+		if (*current == (struct hid_notify*)token) {
+			struct hid_notify* next = (*current)->next;
+			notify = *current;
+			*current = next;
+			break;
+		}
+	}
+
+	if (!notify)
+		return 1;
+
+	free(notify);
+
+	/* Unregister device connection notification on removing last callback */
+	if (notify_context.notifys == NULL) {
+		/* Cleanup connected device list */
+		hid_free_enumeration(notify_context.devs);
+		notify_context.devs = NULL;
+
+		if (notify_context.notify_handle != NULL) {
+			CONFIGRET cr = CM_Unregister_Notification(notify_context.notify_handle);
+			notify_context.notify_handle = NULL;
+			if (cr != CR_SUCCESS) {
+				return 1;
+			}
+		}
+	}
+
+	return 0;
+}
+
 
 HID_API_EXPORT hid_device * HID_API_CALL hid_open(unsigned short vendor_id, unsigned short product_id, const wchar_t *serial_number)
 {

windows/hidapi.vcxproj

@@ -98,7 +98,7 @@
       <DebugInformationFormat>EditAndContinue</DebugInformationFormat>
     </ClCompile>
     <Link>
-      <AdditionalDependencies>setupapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>setupapi.lib;cfgmgr32.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <SubSystem>Windows</SubSystem>
       <TargetMachine>MachineX86</TargetMachine>
@@ -117,7 +117,7 @@
       <DebugInformationFormat>EditAndContinue</DebugInformationFormat>
     </ClCompile>
     <Link>
-      <AdditionalDependencies>setupapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>setupapi.lib;cfgmgr32.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <SubSystem>Windows</SubSystem>
     </Link>
@@ -135,7 +135,7 @@
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
     </ClCompile>
     <Link>
-      <AdditionalDependencies>setupapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>setupapi.lib;cfgmgr32.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <SubSystem>Windows</SubSystem>
       <OptimizeReferences>true</OptimizeReferences>
@@ -157,7 +157,7 @@
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
     </ClCompile>
     <Link>
-      <AdditionalDependencies>setupapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>setupapi.lib;cfgmgr32.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <SubSystem>Windows</SubSystem>
       <OptimizeReferences>true</OptimizeReferences>