InputCommon: Add XInput2 InputBackend class.

Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp

@@ -62,7 +62,7 @@ void ControllerInterface::Initialize(const WindowSystemInfo& wsi)
   ciface::Win32::Init(wsi.render_window);
 #endif
 #ifdef CIFACE_USE_XLIB
-// nothing needed
+  m_input_backends.emplace_back(ciface::XInput2::CreateInputBackend(this));
 #endif
 #ifdef CIFACE_USE_OSX
   m_input_backends.emplace_back(ciface::Quartz::CreateInputBackend(this));
@@ -162,10 +162,6 @@ void ControllerInterface::RefreshDevices(RefreshReason reason)
 #ifdef CIFACE_USE_WIN32
   ciface::Win32::PopulateDevices(m_wsi.render_window);
 #endif
-#ifdef CIFACE_USE_XLIB
-  if (m_wsi.type == WindowSystemType::X11)
-    ciface::XInput2::PopulateDevices(m_wsi.render_window);
-#endif
 #ifdef CIFACE_USE_ANDROID
   ciface::Android::PopulateDevices();
 #endif
@@ -214,9 +210,6 @@ void ControllerInterface::Shutdown()
 #ifdef CIFACE_USE_WIN32
   ciface::Win32::DeInit();
 #endif
-#ifdef CIFACE_USE_XLIB
-// nothing needed
-#endif
 #ifdef CIFACE_USE_ANDROID
   ciface::Android::Shutdown();
 #endif

Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.cpp

@@ -66,9 +66,27 @@ constexpr int XINPUT_MAJOR = 2, XINPUT_MINOR = 1;
 
 namespace ciface::XInput2
 {
-// This function will add zero or more KeyboardMouse objects to devices.
-void PopulateDevices(void* const hwnd)
+class InputBackend final : public ciface::InputBackend
 {
+public:
+  using ciface::InputBackend::InputBackend;
+  void PopulateDevices() override;
+};
+
+std::unique_ptr<ciface::InputBackend> CreateInputBackend(ControllerInterface* controller_interface)
+{
+  return std::make_unique<InputBackend>(controller_interface);
+}
+
+// This function will add zero or more KeyboardMouse objects to devices.
+void InputBackend::PopulateDevices()
+{
+  const WindowSystemInfo wsi = GetControllerInterface().GetWindowSystemInfo();
+  if (wsi.type != WindowSystemType::X11)
+    return;
+
+  const auto hwnd = wsi.render_window;
+
   Display* dpy = XOpenDisplay(nullptr);
 
   // xi_opcode is important; it will be used to identify XInput events by
@@ -119,7 +137,7 @@ void PopulateDevices(void* const hwnd)
       }
       // Since current_master is a master pointer, its attachment must
       // be a master keyboard.
-      g_controller_interface.AddDevice(
+      GetControllerInterface().AddDevice(
           std::make_shared<KeyboardMouse>((Window)hwnd, xi_opcode, current_master->deviceid,
                                           current_master->attachment, scroll_increment));
     }

Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.h

@@ -16,10 +16,11 @@ extern "C" {
 #include "Common/CommonTypes.h"
 #include "Common/Matrix.h"
 #include "InputCommon/ControllerInterface/ControllerInterface.h"
+#include "InputCommon/ControllerInterface/InputBackend.h"
 
 namespace ciface::XInput2
 {
-void PopulateDevices(void* const hwnd);
+std::unique_ptr<ciface::InputBackend> CreateInputBackend(ControllerInterface* controller_interface);
 
 class KeyboardMouse : public Core::Device
 {