Add evdev controller interface

src/frontend-common/evdev_controller_interface.h

@@ -0,0 +1,97 @@
+#pragma once
+#include "controller_interface.h"
+#include "core/types.h"
+#include <libevdev/libevdev.h>
+#include <array>
+#include <functional>
+#include <mutex>
+#include <vector>
+
+class EvdevControllerInterface final : public ControllerInterface
+{
+public:
+  EvdevControllerInterface();
+  ~EvdevControllerInterface() override;
+
+  Backend GetBackend() const override;
+  bool Initialize(CommonHostInterface* host_interface) override;
+  void Shutdown() override;
+
+  // Removes all bindings. Call before setting new bindings.
+  void ClearBindings() override;
+
+  // Binding to events. If a binding for this axis/button already exists, returns false.
+  bool BindControllerAxis(int controller_index, int axis_number, AxisSide axis_side, AxisCallback callback) override;
+  bool BindControllerButton(int controller_index, int button_number, ButtonCallback callback) override;
+  bool BindControllerAxisToButton(int controller_index, int axis_number, bool direction,
+                                  ButtonCallback callback) override;
+  bool BindControllerHatToButton(int controller_index, int hat_number, std::string_view hat_position,
+                                 ButtonCallback callback) override;
+  bool BindControllerButtonToAxis(int controller_index, int button_number, AxisCallback callback) override;
+
+  // Changing rumble strength.
+  u32 GetControllerRumbleMotorCount(int controller_index) override;
+  void SetControllerRumbleStrength(int controller_index, const float* strengths, u32 num_motors) override;
+
+  // Set deadzone that will be applied on axis-to-button mappings
+  bool SetControllerDeadzone(int controller_index, float size = 0.25f) override;
+
+  void PollEvents() override;
+
+private:
+  enum class Axis : u32
+  {
+    LeftX,
+    LeftY,
+    RightX,
+    RightY,
+    LeftTrigger,
+    RightTrigger
+  };
+
+  struct ControllerData
+  {
+    ControllerData(int fd_, struct libevdev* obj_);
+    ControllerData(const ControllerData&) = delete;
+    ControllerData(ControllerData&& move);
+    ~ControllerData();
+
+    ControllerData& operator=(const ControllerData&) = delete;
+    ControllerData& operator=(ControllerData&& move);
+
+    struct libevdev* obj = nullptr;
+    int fd = -1;
+    int controller_id = 0;
+    u32 num_motors = 0;
+
+    float deadzone = 0.25f;
+
+    struct Axis
+    {
+      u32 id;
+      std::array<AxisCallback, 3> callback;
+      std::array<ButtonCallback, 2> button_callback;
+    };
+
+    struct Button
+    {
+      u32 id;
+      ButtonCallback callback;
+      AxisCallback axis_callback;
+    };
+    
+    std::vector<Axis> axises;
+    std::vector<Button> buttons;
+  };
+
+  ControllerData* GetControllerById(int id);
+  bool InitializeController(int index, ControllerData* cd);
+  void HandleControllerEvents(ControllerData* cd);
+  bool HandleAxisEvent(ControllerData* cd, u32 axis, s32 value);
+  bool HandleButtonEvent(ControllerData* cd, u32 button, int button_id, bool pressed);
+
+  std::vector<ControllerData> m_controllers;
+
+  std::mutex m_event_intercept_mutex;
+  Hook::Callback m_event_intercept_callback;
+};