feat(windows): add keyboard/mouse support and expose global UMDF control-device path (#34)

Author: ReenigneArcher

README.md

@@ -99,13 +99,16 @@ be compiler-neutral: prefer a stable C ABI, named pipe, device interface IOCTL,
 or similar control channel over passing C++ STL types across that boundary.
 
 The current Windows backend selects a UMDF control-channel implementation for
-`BackendKind::platform_default`. It probes `\\.\LibVirtualHid`, reports
-`requires_installed_driver = true`, and only advertises gamepad/output-report
-support when the driver package is installed and the control device can be
-opened. The client library stays buildable with MSVC and MinGW/UCRT64 because
-the backend talks to the driver through fixed-size C protocol structures and
-Win32 `DeviceIoControl` calls. The default control device path can be overridden
-for diagnostics with `LIBVIRTUALHID_WINDOWS_CONTROL_DEVICE`.
+`BackendKind::platform_default`. It always exposes keyboard and mouse through
+Win32 `SendInput`, then probes `\\.\LibVirtualHid` for descriptor-driven virtual
+gamepads. It reports `requires_installed_driver = true`, and only advertises
+gamepad/output-report support when the driver package is installed and the
+control device can be opened. Touchscreen, trackpad, and pen tablet support are
+not implemented in the Windows backend yet. The client library stays buildable
+with MSVC and MinGW/UCRT64 because the gamepad path talks to the driver through
+fixed-size C protocol structures and Win32 `DeviceIoControl` calls. The default
+control device path can be overridden for diagnostics with
+`LIBVIRTUALHID_WINDOWS_CONTROL_DEVICE`.
 
 The UMDF driver uses Windows Virtual HID Framework (VHF) for OS-visible gamepad
 devices. Create requests start a VHF child device from the requested descriptor,

src/CMakeLists.txt

@@ -12,8 +12,15 @@ target_sources(${PROJECT_NAME}
 
 if(LIBVIRTUALHID_USES_THREADS)
     find_package(Threads REQUIRED)
-    find_package(PkgConfig REQUIRED)
-    pkg_check_modules(LIBEVDEV REQUIRED IMPORTED_TARGET libevdev)
+    if(LIBEVDEV_CUSTOM_INCLUDE_DIR AND LIBEVDEV_CUSTOM_LIBRARY)
+        add_library(PkgConfig::LIBEVDEV UNKNOWN IMPORTED)
+        set_target_properties(PkgConfig::LIBEVDEV PROPERTIES
+          IMPORTED_LOCATION "${LIBEVDEV_CUSTOM_LIBRARY}"
+          INTERFACE_INCLUDE_DIRECTORIES "${LIBEVDEV_CUSTOM_INCLUDE_DIR}")
+    else()
+        find_package(PkgConfig REQUIRED)
+        pkg_check_modules(LIBEVDEV REQUIRED IMPORTED_TARGET libevdev)
+    endif()
     if(LIBVIRTUALHID_ENABLE_XTEST)
         find_package(X11 QUIET)
     endif()

src/platform/windows/control_protocol.hpp

@@ -23,6 +23,7 @@
 namespace lvh::detail::windows {
 
   inline constexpr std::string_view default_control_device_path {LVH_WINDOWS_CONTROL_DEVICE_PATH};
+  inline constexpr std::string_view global_control_device_path {LVH_WINDOWS_GLOBAL_CONTROL_DEVICE_PATH};
 
   inline std::uint32_t gamepad_flags(const GamepadProfileCapabilities &capabilities) {
     std::uint32_t flags = 0;

src/platform/windows/driver/libvirtualhid_umdf.cpp

@@ -53,6 +53,7 @@ EVT_VHF_ASYNC_OPERATION LvhEvtVhfWriteReport;
 namespace {
 
   constexpr auto symbolic_link_name = L"\\DosDevices\\LibVirtualHid";
+  constexpr auto global_symbolic_link_name = L"\\DosDevices\\Global\\LibVirtualHid";
 
   struct DeviceRecord {
     std::mutex mutex;
@@ -472,12 +473,15 @@ NTSTATUS LvhEvtDeviceAdd(WDFDRIVER driver, PWDFDEVICE_INIT device_init) {
   }
 
   UNICODE_STRING symbolic_link;
-  RtlInitUnicodeString(&symbolic_link, symbolic_link_name);
+  RtlInitUnicodeString(&symbolic_link, global_symbolic_link_name);
   status = WdfDeviceCreateSymbolicLink(device, &symbolic_link);
   if (!NT_SUCCESS(status)) {
     return status;
   }
 
+  RtlInitUnicodeString(&symbolic_link, symbolic_link_name);
+  static_cast<void>(WdfDeviceCreateSymbolicLink(device, &symbolic_link));
+
   status = initialize_vhf_target(device);
   if (!NT_SUCCESS(status)) {
     return status;

src/platform/windows/shared/lvh_windows_protocol.h

@@ -10,6 +10,7 @@
 
 inline constexpr uint32_t LVH_WINDOWS_CONTROL_PROTOCOL_VERSION = 1u;
 inline constexpr char LVH_WINDOWS_CONTROL_DEVICE_PATH[] = R"(\\.\LibVirtualHid)";
+inline constexpr char LVH_WINDOWS_GLOBAL_CONTROL_DEVICE_PATH[] = R"(\\.\Global\LibVirtualHid)";
 
 inline constexpr uint32_t LVH_WINDOWS_MAX_REPORT_DESCRIPTOR_SIZE = 1024u;
 inline constexpr uint32_t LVH_WINDOWS_MAX_INPUT_REPORT_SIZE = 256u;
@@ -161,6 +162,7 @@ enum {
 };
 
 static const char LVH_WINDOWS_CONTROL_DEVICE_PATH[] = "\\\\.\\LibVirtualHid";
+static const char LVH_WINDOWS_GLOBAL_CONTROL_DEVICE_PATH[] = "\\\\.\\Global\\LibVirtualHid";
 
 static const uint32_t LVH_WINDOWS_IOCTL_CREATE_GAMEPAD = 0x8000E000u;
 static const uint32_t LVH_WINDOWS_IOCTL_DESTROY_DEVICE = 0x8000E004u;