Qt: Implement GBA host and widget

Source/Core/DolphinQt/GBAWidget.h

@@ -0,0 +1,96 @@
+// Copyright 2021 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <memory>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include <QWidget>
+
+#include "Common/CommonTypes.h"
+
+namespace HW::GBA
+{
+class Core;
+}  // namespace HW::GBA
+
+class QCloseEvent;
+class QContextMenuEvent;
+class QDragEnterEvent;
+class QDropEvent;
+class QPaintEvent;
+
+class GBAWidget : public QWidget
+{
+  Q_OBJECT
+public:
+  explicit GBAWidget(std::weak_ptr<HW::GBA::Core> core, int device_number,
+                     std::string_view game_title, int width, int height, QWidget* parent = nullptr,
+                     Qt::WindowFlags flags = {});
+  ~GBAWidget();
+
+  void GameChanged(std::string_view game_title, int width, int height);
+  void SetVideoBuffer(std::vector<u32> video_buffer);
+
+  void SetVolume(int volume);
+  void VolumeDown();
+  void VolumeUp();
+  bool IsMuted();
+  void ToggleMute();
+  void ToggleDisconnect();
+
+  void LoadROM();
+  void UnloadROM();
+  void ResetCore();
+  void DoState(bool export_state);
+  void Resize(int scale);
+
+private:
+  void UpdateTitle();
+  void UpdateVolume();
+
+  void LoadGeometry();
+  void SaveGeometry();
+
+  bool CanControlCore();
+  bool CanResetCore();
+
+  void closeEvent(QCloseEvent* event) override;
+  void contextMenuEvent(QContextMenuEvent* event) override;
+  void paintEvent(QPaintEvent* event) override;
+
+  void dragEnterEvent(QDragEnterEvent* event) override;
+  void dropEvent(QDropEvent* event) override;
+
+  std::weak_ptr<HW::GBA::Core> m_core;
+  std::vector<u32> m_video_buffer;
+  int m_device_number;
+  int m_local_pad;
+  std::string m_game_title;
+  int m_width;
+  int m_height;
+  std::string m_netplayer_name;
+  bool m_is_local_pad;
+  int m_volume;
+  bool m_muted;
+  bool m_force_disconnect;
+};
+
+class GBAWidgetController : public QObject
+{
+  Q_OBJECT
+public:
+  explicit GBAWidgetController() = default;
+  ~GBAWidgetController();
+
+  void Create(std::weak_ptr<HW::GBA::Core> core, int device_number, std::string_view game_title,
+              int width, int height);
+  void GameChanged(std::string_view game_title, int width, int height);
+  void FrameEnded(std::vector<u32> video_buffer);
+
+private:
+  GBAWidget* m_widget{};
+};