rawinput: fix hotplug for keyboard and mouse (#810)

## Link to GitHub Issue or related Pull Request, if one exists
n/a

## Description of change
Fix a long-standing issue of hotplug not working for keyboards and mice.
The code only registered for HID notifications; we also need to do it
for the keyboard GUID and mouse GUID.

## Testing
Confirmed that keyboards and mice can be hot unplugged and plugged.

src/spice2x/rawinput/hotplug.cpp

@@ -4,6 +4,10 @@
 
 #include <dbt.h>
 #include <devguid.h>
+#include <hidclass.h>
+#include <ntddkbd.h>
+#include <ntddmou.h>
+#include <objbase.h>
 
 #include "misc/eamuse.h"
 #include "rawinput.h"
@@ -12,31 +16,42 @@
 
 namespace rawinput {
 
-    DEFINE_GUID(GUID_HID, 0x4D1E55B2L, 0xF16F, 0x11CF, 0x88, 0xCB, 0x00, 0x11, 0x11, 0x00, 0x00, 0x30);
+    static bool is_rawinput_interface(const GUID &guid) {
+        return IsEqualGUID(guid, GUID_DEVINTERFACE_HID)
+            || IsEqualGUID(guid, GUID_DEVINTERFACE_KEYBOARD)
+            || IsEqualGUID(guid, GUID_DEVINTERFACE_MOUSE);
+    }
 
     HotplugManager::HotplugManager(RawInputManager *ri_mgr, HWND hWnd) : ri_mgr(ri_mgr) {
-
+        auto register_notification = [hWnd](const GUID &guid, const char *name) -> HANDLE {
-        // init settings
+            DEV_BROADCAST_DEVICEINTERFACE settings {
-        DEV_BROADCAST_DEVICEINTERFACE settings_hid {
                     .dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE),
                     .dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE,
                     .dbcc_reserved = 0,
-                .dbcc_classguid = GUID_HID,
+                    .dbcc_classguid = guid,
                     .dbcc_name = {0},
             };
 
-        // register notifications
+            auto notification = RegisterDeviceNotification(hWnd, &settings, DEVICE_NOTIFY_WINDOW_HANDLE);
-        this->hotplug_hid = RegisterDeviceNotification(hWnd, &settings_hid, DEVICE_NOTIFY_WINDOW_HANDLE);
+            if (notification == nullptr) {
-        if (this->hotplug_hid == nullptr) {
+                log_warning("hotplug", "failed to register {} notifications: {}", name, GetLastError());
-            log_warning("hotplug", "failed to register HID notifications: {}", GetLastError());
             }
+            return notification;
+        };
+
+        // register notifications
+        this->hotplug_hid = register_notification(GUID_DEVINTERFACE_HID, "HID");
+        this->hotplug_keyboard = register_notification(GUID_DEVINTERFACE_KEYBOARD, "keyboard");
+        this->hotplug_mouse = register_notification(GUID_DEVINTERFACE_MOUSE, "mouse");
     }
 
     HotplugManager::~HotplugManager() {
 
         // unregister notifications
-        if (this->hotplug_hid != nullptr) {
+        for (auto notification : {this->hotplug_hid, this->hotplug_keyboard, this->hotplug_mouse}) {
-            UnregisterDeviceNotification(this->hotplug_hid);
+            if (notification != nullptr) {
+                UnregisterDeviceNotification(notification);
+            }
         }
     }
 
@@ -54,11 +69,16 @@ namespace rawinput {
                     switch (hdr->dbch_devicetype) {
                         case DBT_DEVTYP_DEVICEINTERFACE: {
                             auto dev = (const DEV_BROADCAST_DEVICEINTERFACE *) hdr;
-                            this->ri_mgr->midi_scan_start();
 
-                            // check if class is not HID
+                            // check if this is one of the registered RawInput interfaces
-                            if (memcmp(&dev->dbcc_classguid, &GUID_HID, sizeof(GUID_HID)) != 0)
+                            if (!is_rawinput_interface(dev->dbcc_classguid)) {
                                 break;
+                            }
+
+                            // keyboard and mouse class events accompany the HID event, so scan MIDI only once
+                            if (IsEqualGUID(dev->dbcc_classguid, GUID_DEVINTERFACE_HID)) {
+                                this->ri_mgr->midi_scan_start();
+                            }
 
                             // hotplug
                             std::string name(dev->dbcc_name);
@@ -109,6 +129,9 @@ namespace rawinput {
                     switch (hdr->dbch_devicetype) {
                         case DBT_DEVTYP_DEVICEINTERFACE: {
                             auto dev = (DEV_BROADCAST_DEVICEINTERFACE*) hdr;
+                            if (!is_rawinput_interface(dev->dbcc_classguid)) {
+                                break;
+                            }
                             std::string name(dev->dbcc_name);
 
                             // destruct device

src/spice2x/rawinput/hotplug.h

@@ -9,7 +9,9 @@ namespace rawinput {
     class HotplugManager {
     private:
         RawInputManager *ri_mgr;
-        HANDLE hotplug_hid;
+        HANDLE hotplug_hid = nullptr;
+        HANDLE hotplug_keyboard = nullptr;
+        HANDLE hotplug_mouse = nullptr;
 
     public:
         HotplugManager(RawInputManager *ri_mgr, HWND hwnd);

src/spice2x/rawinput/rawinput.cpp

@@ -246,7 +246,8 @@ void rawinput::RawInputManager::devices_scan_rawinput(const std::string &device_
         return;
     }
 
-    // iterate devices
+    // hotplug gives us an interface path rather than a RawInput handle, so find its
+    // matching entry; an empty path means this is a full device scan
     for (UINT device_cur_index = 0; device_cur_index < device_no; device_cur_index++) {
         auto device = &device_list.get()[device_cur_index];
         if (device_name.length() == 0) {