input_common: Eliminate most global state

Abstracts most of the input mechanisms under an InputSubsystem class
that is managed by the frontends, eliminating any static constructors
and destructors. This gets rid of global accessor functions and also
allows the frontends to have a more fine-grained control over the
lifecycle of the input subsystem.

This also makes it explicit which interfaces rely on the input subsystem
instead of making it opaque in the interface functions. All that remains
to migrate over is the factories, which can be done in a separate
change.

1 files changed, 143 insertions, 107 deletions

diff --git a/src/input_common/main.cpp b/src/input_common/main.cpp
index 8e67a7437..57e7a25fe 100644
--- a/src/input_common/main.cpp
+++ b/src/input_common/main.cpp
@@ -18,66 +18,166 @@
 
 namespace InputCommon {
 
-static std::shared_ptr<Keyboard> keyboard;
-static std::shared_ptr<MotionEmu> motion_emu;
+struct InputSubsystem::Impl {
+    void Initialize() {
+        auto gcadapter = std::make_shared<GCAdapter::Adapter>();
+        gcbuttons = std::make_shared<GCButtonFactory>(gcadapter);
+        Input::RegisterFactory<Input::ButtonDevice>("gcpad", gcbuttons);
+        gcanalog = std::make_shared<GCAnalogFactory>(gcadapter);
+        Input::RegisterFactory<Input::AnalogDevice>("gcpad", gcanalog);
+
+        keyboard = std::make_shared<Keyboard>();
+        Input::RegisterFactory<Input::ButtonDevice>("keyboard", keyboard);
+        Input::RegisterFactory<Input::AnalogDevice>("analog_from_button",
+                                                    std::make_shared<AnalogFromButton>());
+        motion_emu = std::make_shared<MotionEmu>();
+        Input::RegisterFactory<Input::MotionDevice>("motion_emu", motion_emu);
+
 #ifdef HAVE_SDL2
-static std::unique_ptr<SDL::State> sdl;
+        sdl = SDL::Init();
 #endif
-static std::unique_ptr<CemuhookUDP::State> udp;
-static std::shared_ptr<GCButtonFactory> gcbuttons;
-static std::shared_ptr<GCAnalogFactory> gcanalog;
-
-void Init() {
-    auto gcadapter = std::make_shared<GCAdapter::Adapter>();
-    gcbuttons = std::make_shared<GCButtonFactory>(gcadapter);
-    Input::RegisterFactory<Input::ButtonDevice>("gcpad", gcbuttons);
-    gcanalog = std::make_shared<GCAnalogFactory>(gcadapter);
-    Input::RegisterFactory<Input::AnalogDevice>("gcpad", gcanalog);
-
-    keyboard = std::make_shared<Keyboard>();
-    Input::RegisterFactory<Input::ButtonDevice>("keyboard", keyboard);
-    Input::RegisterFactory<Input::AnalogDevice>("analog_from_button",
-                                                std::make_shared<AnalogFromButton>());
-    motion_emu = std::make_shared<MotionEmu>();
-    Input::RegisterFactory<Input::MotionDevice>("motion_emu", motion_emu);
 
+        udp = CemuhookUDP::Init();
+    }
+
+    void Shutdown() {
+        Input::UnregisterFactory<Input::ButtonDevice>("keyboard");
+        keyboard.reset();
+        Input::UnregisterFactory<Input::AnalogDevice>("analog_from_button");
+        Input::UnregisterFactory<Input::MotionDevice>("motion_emu");
+        motion_emu.reset();
 #ifdef HAVE_SDL2
-    sdl = SDL::Init();
+        sdl.reset();
 #endif
-    udp = CemuhookUDP::Init();
-}
+        udp.reset();
+        Input::UnregisterFactory<Input::ButtonDevice>("gcpad");
+        Input::UnregisterFactory<Input::AnalogDevice>("gcpad");
+
+        gcbuttons.reset();
+        gcanalog.reset();
+    }
+
+    [[nodiscard]] std::vector<Common::ParamPackage> GetInputDevices() const {
+        std::vector<Common::ParamPackage> devices = {
+            Common::ParamPackage{{"display", "Any"}, {"class", "any"}},
+            Common::ParamPackage{{"display", "Keyboard/Mouse"}, {"class", "key"}},
+        };
+#ifdef HAVE_SDL2
+        auto sdl_devices = sdl->GetInputDevices();
+        devices.insert(devices.end(), sdl_devices.begin(), sdl_devices.end());
+#endif
+        auto udp_devices = udp->GetInputDevices();
+        devices.insert(devices.end(), udp_devices.begin(), udp_devices.end());
+        return devices;
+    }
+
+    [[nodiscard]] AnalogMapping GetAnalogMappingForDevice(
+        const Common::ParamPackage& params) const {
+        if (!params.Has("class") || params.Get("class", "") == "any") {
+            return {};
+        }
+        if (params.Get("class", "") == "key") {
+            // TODO consider returning the SDL key codes for the default keybindings
+            return {};
+        }
+#ifdef HAVE_SDL2
+        if (params.Get("class", "") == "sdl") {
+            return sdl->GetAnalogMappingForDevice(params);
+        }
+#endif
+        return {};
+    }
+
+    [[nodiscard]] ButtonMapping GetButtonMappingForDevice(
+        const Common::ParamPackage& params) const {
+        if (!params.Has("class") || params.Get("class", "") == "any") {
+            return {};
+        }
+        if (params.Get("class", "") == "key") {
+            // TODO consider returning the SDL key codes for the default keybindings
+            return {};
+        }
+#ifdef HAVE_SDL2
+        if (params.Get("class", "") == "sdl") {
+            return sdl->GetButtonMappingForDevice(params);
+        }
+#endif
+        return {};
+    }
 
-void Shutdown() {
-    Input::UnregisterFactory<Input::ButtonDevice>("keyboard");
-    keyboard.reset();
-    Input::UnregisterFactory<Input::AnalogDevice>("analog_from_button");
-    Input::UnregisterFactory<Input::MotionDevice>("motion_emu");
-    motion_emu.reset();
+    std::shared_ptr<Keyboard> keyboard;
+    std::shared_ptr<MotionEmu> motion_emu;
 #ifdef HAVE_SDL2
-    sdl.reset();
+    std::unique_ptr<SDL::State> sdl;
 #endif
-    udp.reset();
-    Input::UnregisterFactory<Input::ButtonDevice>("gcpad");
-    Input::UnregisterFactory<Input::AnalogDevice>("gcpad");
+    std::unique_ptr<CemuhookUDP::State> udp;
+    std::shared_ptr<GCButtonFactory> gcbuttons;
+    std::shared_ptr<GCAnalogFactory> gcanalog;
+};
+
+InputSubsystem::InputSubsystem() : impl{std::make_unique<Impl>()} {}
+
+InputSubsystem::~InputSubsystem() = default;
+
+void InputSubsystem::Initialize() {
+    impl->Initialize();
+}
+
+void InputSubsystem::Shutdown() {
+    impl->Shutdown();
+}
+
+Keyboard* InputSubsystem::GetKeyboard() {
+    return impl->keyboard.get();
+}
+
+const Keyboard* InputSubsystem::GetKeyboard() const {
+    return impl->keyboard.get();
+}
+
+MotionEmu* InputSubsystem::GetMotionEmu() {
+    return impl->motion_emu.get();
+}
+
+const MotionEmu* InputSubsystem::GetMotionEmu() const {
+    return impl->motion_emu.get();
+}
+
+std::vector<Common::ParamPackage> InputSubsystem::GetInputDevices() const {
+    return impl->GetInputDevices();
+}
+
+AnalogMapping InputSubsystem::GetAnalogMappingForDevice(const Common::ParamPackage& device) const {
+    return impl->GetAnalogMappingForDevice(device);
+}
 
-    gcbuttons.reset();
-    gcanalog.reset();
+ButtonMapping InputSubsystem::GetButtonMappingForDevice(const Common::ParamPackage& device) const {
+    return impl->GetButtonMappingForDevice(device);
 }
 
-Keyboard* GetKeyboard() {
-    return keyboard.get();
+GCAnalogFactory* InputSubsystem::GetGCAnalogs() {
+    return impl->gcanalog.get();
 }
 
-MotionEmu* GetMotionEmu() {
-    return motion_emu.get();
+const GCAnalogFactory* InputSubsystem::GetGCAnalogs() const {
+    return impl->gcanalog.get();
 }
 
-GCButtonFactory* GetGCButtons() {
-    return gcbuttons.get();
+GCButtonFactory* InputSubsystem::GetGCButtons() {
+    return impl->gcbuttons.get();
 }
 
-GCAnalogFactory* GetGCAnalogs() {
-    return gcanalog.get();
+const GCButtonFactory* InputSubsystem::GetGCButtons() const {
+    return impl->gcbuttons.get();
+}
+
+std::vector<std::unique_ptr<Polling::DevicePoller>> InputSubsystem::GetPollers(
+    Polling::DeviceType type) const {
+#ifdef HAVE_SDL2
+    return impl->sdl->GetPollers(type);
+#else
+    return {};
+#endif
 }
 
 std::string GenerateKeyboardParam(int key_code) {
@@ -101,68 +201,4 @@ std::string GenerateAnalogParamFromKeys(int key_up, int key_down, int key_left,
     };
     return circle_pad_param.Serialize();
 }
-
-std::vector<Common::ParamPackage> GetInputDevices() {
-    std::vector<Common::ParamPackage> devices = {
-        Common::ParamPackage{{"display", "Any"}, {"class", "any"}},
-        Common::ParamPackage{{"display", "Keyboard/Mouse"}, {"class", "key"}},
-    };
-#ifdef HAVE_SDL2
-    auto sdl_devices = sdl->GetInputDevices();
-    devices.insert(devices.end(), sdl_devices.begin(), sdl_devices.end());
-#endif
-    auto udp_devices = udp->GetInputDevices();
-    devices.insert(devices.end(), udp_devices.begin(), udp_devices.end());
-    return devices;
-}
-
-std::unordered_map<Settings::NativeButton::Values, Common::ParamPackage> GetButtonMappingForDevice(
-    const Common::ParamPackage& params) {
-    std::unordered_map<Settings::NativeButton::Values, Common::ParamPackage> mappings;
-    if (!params.Has("class") || params.Get("class", "") == "any") {
-        return {};
-    }
-    if (params.Get("class", "") == "key") {
-        // TODO consider returning the SDL key codes for the default keybindings
-        return {};
-    }
-#ifdef HAVE_SDL2
-    if (params.Get("class", "") == "sdl") {
-        return sdl->GetButtonMappingForDevice(params);
-    }
-#endif
-    return {};
-}
-
-std::unordered_map<Settings::NativeAnalog::Values, Common::ParamPackage> GetAnalogMappingForDevice(
-    const Common::ParamPackage& params) {
-    std::unordered_map<Settings::NativeAnalog::Values, Common::ParamPackage> mappings;
-    if (!params.Has("class") || params.Get("class", "") == "any") {
-        return {};
-    }
-    if (params.Get("class", "") == "key") {
-        // TODO consider returning the SDL key codes for the default keybindings
-        return {};
-    }
-#ifdef HAVE_SDL2
-    if (params.Get("class", "") == "sdl") {
-        return sdl->GetAnalogMappingForDevice(params);
-    }
-#endif
-    return {};
-}
-
-namespace Polling {
-
-std::vector<std::unique_ptr<DevicePoller>> GetPollers(DeviceType type) {
-    std::vector<std::unique_ptr<DevicePoller>> pollers;
-
-#ifdef HAVE_SDL2
-    pollers = sdl->GetPollers(type);
-#endif
-
-    return pollers;
-}
-
-} // namespace Polling
 } // namespace InputCommon