Kernel: Rename Keyboard to KeyboardDevice.

Kernel/KeyboardDevice.h

@@ -0,0 +1,55 @@
+#pragma once
+
+#include <AK/Types.h>
+#include <AK/DoublyLinkedList.h>
+#include <AK/CircularQueue.h>
+#include <Kernel/CharacterDevice.h>
+#include "IRQHandler.h"
+#include "KeyCode.h"
+
+class KeyboardClient;
+
+class KeyboardDevice final : public IRQHandler, public CharacterDevice {
+    AK_MAKE_ETERNAL
+public:
+    using Event = KeyEvent;
+
+    [[gnu::pure]] static KeyboardDevice& the();
+
+    virtual ~KeyboardDevice() override;
+    KeyboardDevice();
+
+    void set_client(KeyboardClient* client) { m_client = client; }
+
+    // ^CharacterDevice
+    virtual ssize_t read(Process&, byte* buffer, size_t) override;
+    virtual bool can_read(Process&) const override;
+    virtual ssize_t write(Process&, const byte* buffer, size_t) override;
+    virtual bool can_write(Process&) const override { return true; }
+
+private:
+    // ^IRQHandler
+    virtual void handle_irq() override;
+
+    // ^CharacterDevice
+    virtual const char* class_name() const override { return "KeyboardDevice"; }
+
+    void key_state_changed(byte raw, bool pressed);
+    void update_modifier(byte modifier, bool state)
+    {
+        if (state)
+            m_modifiers |= modifier;
+        else
+            m_modifiers &= ~modifier;
+    }
+
+    KeyboardClient* m_client { nullptr };
+    CircularQueue<Event, 16> m_queue;
+    byte m_modifiers { 0 };
+};
+
+class KeyboardClient {
+public:
+    virtual ~KeyboardClient();
+    virtual void on_key_pressed(KeyboardDevice::Event) = 0;
+};