core/hid: Improve accuracy of the keyboard implementation

src/input_common/drivers/keyboard.cpp

@@ -3,26 +3,71 @@
 // Refer to the license.txt file included
 
 #include "common/param_package.h"
+#include "common/settings_input.h"
 #include "input_common/drivers/keyboard.h"
 
 namespace InputCommon {
 
-constexpr PadIdentifier identifier = {
+constexpr PadIdentifier key_identifier = {
     .guid = Common::UUID{Common::INVALID_UUID},
     .port = 0,
     .pad = 0,
 };
+constexpr PadIdentifier modifier_identifier = {
+    .guid = Common::UUID{Common::INVALID_UUID},
+    .port = 0,
+    .pad = 1,
+};
 
 Keyboard::Keyboard(const std::string& input_engine_) : InputEngine(input_engine_) {
-    PreSetController(identifier);
+    PreSetController(key_identifier);
+    PreSetController(modifier_identifier);
 }
 
 void Keyboard::PressKey(int key_code) {
-    SetButton(identifier, key_code, true);
+    SetButton(key_identifier, key_code, true);
 }
 
 void Keyboard::ReleaseKey(int key_code) {
-    SetButton(identifier, key_code, false);
+    SetButton(key_identifier, key_code, false);
+}
+
+void Keyboard::SetModifiers(int key_modifiers) {
+    for (int i = 0; i < 32; ++i) {
+        bool key_value = ((key_modifiers >> i) & 0x1) != 0;
+        SetButton(modifier_identifier, i, key_value);
+        // Use the modifier to press the key button equivalent
+        switch (i) {
+        case Settings::NativeKeyboard::LeftControl:
+            SetButton(key_identifier, Settings::NativeKeyboard::LeftControlKey, key_value);
+            break;
+        case Settings::NativeKeyboard::LeftShift:
+            SetButton(key_identifier, Settings::NativeKeyboard::LeftShiftKey, key_value);
+            break;
+        case Settings::NativeKeyboard::LeftAlt:
+            SetButton(key_identifier, Settings::NativeKeyboard::LeftAltKey, key_value);
+            break;
+        case Settings::NativeKeyboard::LeftMeta:
+            SetButton(key_identifier, Settings::NativeKeyboard::LeftMetaKey, key_value);
+            break;
+        case Settings::NativeKeyboard::RightControl:
+            SetButton(key_identifier, Settings::NativeKeyboard::RightControlKey, key_value);
+            break;
+        case Settings::NativeKeyboard::RightShift:
+            SetButton(key_identifier, Settings::NativeKeyboard::RightShiftKey, key_value);
+            break;
+        case Settings::NativeKeyboard::RightAlt:
+            SetButton(key_identifier, Settings::NativeKeyboard::RightAltKey, key_value);
+            break;
+        case Settings::NativeKeyboard::RightMeta:
+            SetButton(key_identifier, Settings::NativeKeyboard::RightMetaKey, key_value);
+            break;
+        default:
+            // Other modifier keys should be pressed with PressKey since they stay enabled until
+            // next press
+            break;
+        }
+    }
 }
 
 void Keyboard::ReleaseAllKeys() {

src/input_common/drivers/keyboard.h

@@ -28,6 +28,13 @@ public:
      */
     void ReleaseKey(int key_code);
 
+    /**
+     * Sets the status of all keyboard modifier keys
+     * @param key_modifiers the code of the key to release
+     */
+    void SetModifiers(int key_modifiers);
+
+    /// Sets all keys to the non pressed state
     void ReleaseAllKeys();
 
     /// Used for automapping features

src/input_common/main.cpp

@@ -402,6 +402,15 @@ std::string GenerateKeyboardParam(int key_code) {
     return param.Serialize();
 }
 
+std::string GenerateModdifierKeyboardParam(int key_code) {
+    Common::ParamPackage param;
+    param.Set("engine", "keyboard");
+    param.Set("code", key_code);
+    param.Set("toggle", false);
+    param.Set("pad", 1);
+    return param.Serialize();
+}
+
 std::string GenerateAnalogParamFromKeys(int key_up, int key_down, int key_left, int key_right,
                                         int key_modifier, float modifier_scale) {
     Common::ParamPackage circle_pad_param{

src/input_common/main.h

@@ -134,6 +134,9 @@ private:
 /// Generates a serialized param package for creating a keyboard button device.
 std::string GenerateKeyboardParam(int key_code);
 
+/// Generates a serialized param package for creating a moddifier keyboard button device.
+std::string GenerateModdifierKeyboardParam(int key_code);
+
 /// Generates a serialized param package for creating an analog device taking input from keyboard.
 std::string GenerateAnalogParamFromKeys(int key_up, int key_down, int key_left, int key_right,
                                         int key_modifier, float modifier_scale);