From 951b6edccd2d93e2f5831d502882fb828e76bb1c Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Fri, 17 May 2013 15:30:13 +0200
Subject: [PATCH] Improve kernel terminal line editing.

---
 sortix/linebuffer.cpp  |  9 ++++-
 sortix/linebuffer.h    |  3 +-
 sortix/logterminal.cpp | 84 +++++++++++++++++++++++++++++++++---------
 3 files changed, 76 insertions(+), 20 deletions(-)

diff --git a/sortix/linebuffer.cpp b/sortix/linebuffer.cpp
index 1999d7e2..9f78ecdd 100644
--- a/sortix/linebuffer.cpp
+++ b/sortix/linebuffer.cpp
@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2012.
+    Copyright(C) Jonas 'Sortie' Termansen 2012, 2013.
 
     This file is part of Sortix.
 
@@ -99,6 +99,13 @@ namespace Sortix
 		return buffer[index];
 	}
 
+	uint32_t LineBuffer::WouldBackspace() const
+	{
+		if ( !CanBackspace() ) { return 0; }
+		size_t index = OffsetIndex(bufferoffset, bufferused-1, bufferlength);
+		return buffer[index];
+	}
+
 	void LineBuffer::Commit()
 	{
 		buffercommitted = bufferfrozen = bufferused;
diff --git a/sortix/linebuffer.h b/sortix/linebuffer.h
index 303137ea..815ff5b1 100644
--- a/sortix/linebuffer.h
+++ b/sortix/linebuffer.h
@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2012.
+    Copyright(C) Jonas 'Sortie' Termansen 2012, 2013.
 
     This file is part of Sortix.
 
@@ -38,6 +38,7 @@ namespace Sortix
 		uint32_t Pop();
 		uint32_t Peek() const;
 		uint32_t Backspace();
+		uint32_t WouldBackspace() const;
 		void Commit();
 		void Freeze();
 		bool CanPop() const;
diff --git a/sortix/logterminal.cpp b/sortix/logterminal.cpp
index 6ff11baf..7a3df6c3 100644
--- a/sortix/logterminal.cpp
+++ b/sortix/logterminal.cpp
@@ -22,27 +22,31 @@
 
 *******************************************************************************/
 
-#include <sortix/kernel/platform.h>
-#include <sortix/kernel/refcount.h>
-#include <sortix/kernel/kthread.h>
-#include <sortix/kernel/interlock.h>
-#include <sortix/kernel/ioctx.h>
-#include <sortix/kernel/inode.h>
-#include <sortix/kernel/keyboard.h>
-#include <sortix/kernel/poll.h>
-#include <sortix/kernel/scheduler.h>
-#include <sortix/kernel/process.h>
-
-#include <sortix/fcntl.h>
-#include <sortix/termmode.h>
-#include <sortix/termios.h>
-#include <sortix/keycodes.h>
-#include <sortix/signal.h>
-#include <sortix/stat.h>
-#include <sortix/poll.h>
+#include <sys/types.h>
 
 #include <errno.h>
 #include <string.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+#include <sortix/fcntl.h>
+#include <sortix/keycodes.h>
+#include <sortix/poll.h>
+#include <sortix/signal.h>
+#include <sortix/stat.h>
+#include <sortix/termios.h>
+#include <sortix/termmode.h>
+
+#include <sortix/kernel/platform.h>
+#include <sortix/kernel/inode.h>
+#include <sortix/kernel/interlock.h>
+#include <sortix/kernel/ioctx.h>
+#include <sortix/kernel/keyboard.h>
+#include <sortix/kernel/kthread.h>
+#include <sortix/kernel/poll.h>
+#include <sortix/kernel/process.h>
+#include <sortix/kernel/refcount.h>
+#include <sortix/kernel/scheduler.h>
 
 #include "utf8.h"
 #include "logterminal.h"
@@ -166,6 +170,50 @@ void LogTerminal::ProcessKeystroke(int kbkey)
 		return;
 	}
 
+	if ( termmode & TERMMODE_LINEBUFFER && control && kbkey == KBKEY_W )
+	{
+		bool had_non_whitespace = false;
+	c_w_delete_more:
+		if ( !linebuffer.CanBackspace() ) { return; }
+		uint32_t delchar = linebuffer.WouldBackspace();
+		bool waskbkey = KBKEY_DECODE(delchar);
+		bool wasuni = !waskbkey;
+		bool whitespace =
+			(wasuni && (delchar == ' ' ||
+			            delchar == '\t' ||
+			            delchar == '\n')) ||
+			(waskbkey && (abs(KBKEY_DECODE(delchar)) == -KBKEY_SPACE ||
+			              abs(KBKEY_DECODE(delchar)) == -KBKEY_TAB ||
+			              abs(KBKEY_DECODE(delchar)) == -KBKEY_ENTER));
+		if ( wasuni && whitespace && had_non_whitespace )
+			return;
+		if ( wasuni && !whitespace )
+			had_non_whitespace = true;
+		linebuffer.Backspace();
+		if ( (!waskbkey || termmode & TERMMODE_KBKEY) &&
+		     (!wasuni || termmode & TERMMODE_UNICODE) &&
+		     termmode & TERMMODE_ECHO &&
+		     wasuni )
+				Log::Print("\b");
+		goto c_w_delete_more;
+	}
+
+	if ( termmode & TERMMODE_LINEBUFFER && control && kbkey == KBKEY_U )
+	{
+		while ( linebuffer.CanBackspace() )
+		{
+			uint32_t delchar = linebuffer.Backspace();
+			bool waskbkey = KBKEY_DECODE(delchar);
+			bool wasuni = !waskbkey;
+			if ( (!waskbkey || termmode & TERMMODE_KBKEY) &&
+				 (!wasuni || termmode & TERMMODE_UNICODE) &&
+				 termmode & TERMMODE_ECHO &&
+				 wasuni )
+				Log::Print("\b");
+		}
+		return;
+	}
+
 	uint32_t unikbkey = KBKEY_ENCODE(kbkey);
 	QueueUnicode(unikbkey);
 	uint32_t unicode = kblayout->Translate(kbkey);