feat: add keyboard layout support

kernel/src/Drivers/PS2/Keyboard.cpp

@@ -179,7 +179,9 @@ namespace Drivers::PS2::Keyboard {
                 .Shift    = g_Modifiers.LeftShift || g_Modifiers.RightShift,
                 .Ctrl     = g_Modifiers.LeftCtrl || g_Modifiers.RightCtrl,
                 .Alt      = g_Modifiers.LeftAlt || g_Modifiers.RightAlt,
-                .CapsLock = g_Modifiers.CapsLock
+                .CapsLock = g_Modifiers.CapsLock,
+                .AltGr    = g_Modifiers.RightAlt,
+                .Extended = true
             };
             PushAndNotify(event);
 
@@ -237,7 +239,9 @@ namespace Drivers::PS2::Keyboard {
                 .Shift    = g_Modifiers.LeftShift || g_Modifiers.RightShift,
                 .Ctrl     = g_Modifiers.LeftCtrl || g_Modifiers.RightCtrl,
                 .Alt      = g_Modifiers.LeftAlt || g_Modifiers.RightAlt,
-                .CapsLock = g_Modifiers.CapsLock
+                .CapsLock = g_Modifiers.CapsLock,
+                .AltGr    = g_Modifiers.RightAlt,
+                .Extended = false
             };
             PushAndNotify(event);
             return;
@@ -261,7 +265,9 @@ namespace Drivers::PS2::Keyboard {
             .Shift    = g_Modifiers.LeftShift || g_Modifiers.RightShift,
             .Ctrl     = g_Modifiers.LeftCtrl || g_Modifiers.RightCtrl,
             .Alt      = g_Modifiers.LeftAlt || g_Modifiers.RightAlt,
-            .CapsLock = g_Modifiers.CapsLock
+            .CapsLock = g_Modifiers.CapsLock,
+            .AltGr    = g_Modifiers.RightAlt,
+            .Extended = false
         };
 
         PushAndNotify(event);
@@ -298,7 +304,18 @@ namespace Drivers::PS2::Keyboard {
     }
 
     void InjectKeyEvent(const KeyEvent& event) {
-        PushAndNotify(event);
+        // Caps Lock is owned here rather than by each injecting driver: USB HID
+        // reports the key as an ordinary usage and carries no lock state, so
+        // without this the lock would never toggle on a USB keyboard.
+        KeyEvent stamped = event;
+        if (stamped.Scancode == ScCapsLock && stamped.Pressed)
+            g_Modifiers.CapsLock = !g_Modifiers.CapsLock;
+        stamped.CapsLock = g_Modifiers.CapsLock;
+        PushAndNotify(stamped);
+    }
+
+    bool GetCapsLock() {
+        return g_Modifiers.CapsLock;
     }
 
 };

kernel/src/Drivers/PS2/Keyboard.hpp

@@ -18,6 +18,13 @@ namespace Drivers::PS2::Keyboard {
         bool    Ctrl;
         bool    Alt;
         bool    CapsLock;
+        // Right Alt held. Reported separately from Alt so keyboard layouts can
+        // use it as AltGr without swallowing left-Alt shortcuts.
+        bool    AltGr;
+        // Key came from an E0-prefixed (extended) scancode. The prefix is not
+        // part of Scancode, so without this flag keypad "/" is indistinguishable
+        // from the main "/" key and layout translation would rewrite it.
+        bool    Extended;
     };
 
     // Modifier key state
@@ -52,4 +59,8 @@ namespace Drivers::PS2::Keyboard {
     // Inject a key event from an external source (e.g., USB HID keyboard)
     void InjectKeyEvent(const KeyEvent& event);
 
+    // Current Caps Lock state. Injecting drivers (USB HID) need this to
+    // compute ASCII, since the lock is toggled centrally here.
+    bool GetCapsLock();
+
 };