Kernel: Add basic Shell to test functionality

kernel/include/kernel/Shell.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <BAN/String.h>
+#include <kernel/Keyboard.h>
+
+namespace Kernel
+{
+
+	class Shell
+	{
+	public:
+		Shell(const Shell&) = delete;
+
+		static Shell& Get();
+
+		void Run();
+
+	private:
+		Shell();
+		void PrintPrompt();
+		void ProcessCommand(BAN::StringView);
+		void KeyEventCallback(Keyboard::KeyEvent);
+
+	private:
+		BAN::String m_buffer;
+	};
+
+}

kernel/kernel/Shell.cpp

@@ -0,0 +1,147 @@
+#include <BAN/StringView.h>
+#include <BAN/Vector.h>
+#include <kernel/IO.h>
+#include <kernel/Keyboard.h>
+#include <kernel/RTC.h>
+#include <kernel/Shell.h>
+#include <kernel/tty.h>
+
+namespace Kernel
+{
+
+	static Shell* s_instance = nullptr;
+
+	Shell& Shell::Get()
+	{
+		if (!s_instance)
+			s_instance = new Shell();
+		return *s_instance;
+	}
+
+	Shell::Shell()
+	{
+		Keyboard::register_key_event_callback([](Keyboard::KeyEvent event) { Shell::Get().KeyEventCallback(event); });
+		m_buffer.Reserve(128);
+	}
+
+	void Shell::PrintPrompt()
+	{
+		kprint("\e[32muser\e[m# ");
+	}
+
+	void Shell::Run()
+	{
+		PrintPrompt();
+		for (;;)
+		{
+			asm volatile("hlt");
+			Keyboard::update_keyboard();
+		}
+	}
+
+	void Shell::ProcessCommand(BAN::StringView command)
+	{
+		auto arguments = command.Split(' ');
+		if (arguments.Empty())
+			return;
+
+		if (arguments.Front() == "date")
+		{
+			if (arguments.Size() != 1)
+			{
+				kprintln("'date' does not support command line arguments");
+				return;	
+			}
+			auto time = RTC::GetCurrentTime();
+			kprintln("{}", time);
+			return;
+		}
+		
+		if (arguments.Front() == "echo")
+		{
+			if (arguments.Size() > 1)
+			{
+				kprint("{}", arguments[1]);
+				for (size_t i = 2; i < arguments.Size(); i++)
+					kprint(" {}", arguments[i]);
+			}
+			kprintln();
+			return;
+		}
+
+		if (arguments.Front() == "clear")
+		{
+			if (arguments.Size() != 1)
+			{
+				kprintln("'clear' does not support command line arguments");
+				return;	
+			}
+			TTY::clear();
+			TTY::set_cursor_pos(0, 0);
+			return;
+		}
+
+		if (arguments.Front() == "reboot")
+		{
+			if (arguments.Size() != 1)
+			{
+				kprintln("'reboot' does not support command line arguments");
+				return;	
+			}
+			uint8_t good = 0x02;
+			while (good & 0x02)
+				good = IO::inb(0x64);
+			IO::outb(0x64, 0xFE);
+			asm volatile("cli; hlt");
+			return;
+		}
+
+		kprintln("unrecognized command '{}'", arguments.Front());
+	}
+
+	void Shell::KeyEventCallback(Keyboard::KeyEvent event)
+	{
+		if (!event.pressed)
+			return;
+		
+		switch (event.key)
+		{
+			case Keyboard::Key::Backspace:
+			{
+				if (!m_buffer.Empty())
+				{
+					kprint("\b \b", 3);
+					m_buffer.PopBack();
+				}
+				break;
+			}
+
+			case Keyboard::Key::Enter:
+			case Keyboard::Key::NumpadEnter:
+			{
+				kprint("\n");
+				ProcessCommand(m_buffer);
+				m_buffer.Clear();
+				PrintPrompt();
+				break;
+			}
+
+			case Keyboard::Key::Tab:
+				event.key = Keyboard::Key::Space;
+				// fall through
+			
+			default:
+			{
+				char ascii = Keyboard::key_event_to_ascii(event);
+				if (ascii)
+				{
+					kprint("{}", ascii);
+					m_buffer.PushBack(ascii);
+				}
+				break;
+			}
+		}
+	}
+
+
+}

kernel/kernel/kernel.cpp

@@ -10,71 +10,14 @@
 #include <kernel/PIT.h>
 #include <kernel/RTC.h>
 #include <kernel/Serial.h>
+#include <kernel/Shell.h>
 #include <kernel/tty.h>
 
-#include <string.h>
-#include <stdlib.h>
-
 #define DISABLE_INTERRUPTS() asm volatile("cli")
 #define ENABLE_INTERRUPTS() asm volatile("sti")
 
 multiboot_info_t* s_multiboot_info;
 
-char ascii_buffer[32] {};
-static bool has_command(const char* cmd)
-{
-	size_t len = strlen(cmd);
-	return memcmp(ascii_buffer + sizeof(ascii_buffer) - len - 1, cmd, len) == 0;
-}
-void on_key_press(Keyboard::KeyEvent event)
-{
-	if (event.pressed)
-	{
-		char ascii = Keyboard::key_event_to_ascii(event);
-
-		if (ascii)
-		{
-			memmove(ascii_buffer, ascii_buffer + 1, sizeof(ascii_buffer) - 1);
-			ascii_buffer[sizeof(ascii_buffer) - 1] = ascii;
-			kprint("{}", ascii);
-		}
-
-		if (event.key == Keyboard::Key::Escape)
-		{
-			kprint("time since boot: {} ms\n", PIT::ms_since_boot());
-			return;
-		}
-		else if (event.key == Keyboard::Key::Backspace)
-		{
-			memmove(ascii_buffer + 2, ascii_buffer, sizeof(ascii_buffer) - 2);
-			kprint(" \b");
-		}
-		else if (event.key == Keyboard::Key::Enter)
-		{
-			if (has_command("clear"))
-			{
-				TTY::clear();
-				TTY::set_cursor_pos(0, 0);
-			}
-			else if (has_command("led_disco"))
-			{
-				TTY::clear();
-				TTY::set_cursor_pos(0, 0);
-				kprintln("\e[32mLED DISCO\e[m");
-				Keyboard::led_disco();
-			}
-			else if (has_command("reboot"))
-			{
-				uint8_t good = 0x02;
-				while (good & 0x02)
-					good = IO::inb(0x64);
-				IO::outb(0x64, 0xFE);
-				asm volatile("cli; hlt");
-			}
-		}
-	}
-}
-
 extern "C"
 void kernel_main(multiboot_info_t* mbi, uint32_t magic)
 {
@@ -88,10 +31,6 @@ void kernel_main(multiboot_info_t* mbi, uint32_t magic)
 	Serial::initialize();
 	TTY::initialize();
 	
-	for (int i = 30; i <= 37; i++)
-		kprint("\e[{}m#", i);
-	kprint("\e[m\n");
-
 	kmalloc_initialize();
 
 	PIC::initialize();
@@ -99,19 +38,18 @@ void kernel_main(multiboot_info_t* mbi, uint32_t magic)
 	IDT::initialize();
 
 	PIT::initialize();
-	if (!Keyboard::initialize(on_key_press))
+	if (!Keyboard::initialize())
 		return;
 
-	auto time = RTC::GetCurrentTime();
-	kprintln("Today is {}", time);
-
 	kprintln("Hello from the kernel!");
 
 	ENABLE_INTERRUPTS();
 
+	auto& shell = Kernel::Shell::Get();
+	shell.Run();
 
 	for (;;)
 	{
-		Keyboard::update_keyboard();
+		asm("hlt");
 	}
 }