From 00f90246c8259ea171be3e143ec30ea73e923558 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Sun, 30 Oct 2022 18:34:40 +0100
Subject: [PATCH] Kernel: Implement very basic escape sequences for
 TextRenderer

---
 apps/src/sh.c                      |  9 +++-
 kernel/src/render/TextRenderer.cpp | 70 +++++++++++++++++++-----------
 2 files changed, 51 insertions(+), 28 deletions(-)

diff --git a/apps/src/sh.c b/apps/src/sh.c
index 4bf2a099..c1310fb3 100644
--- a/apps/src/sh.c
+++ b/apps/src/sh.c
@@ -113,9 +113,14 @@ int command_match_builtins(command* cmd)
 {
     if (command_matches(cmd, "exit ")) { exit(atoi(cmd->buffer + 5)); }
     if (command_matches_exactly(cmd, "exit")) { exit(0); }
-    if (command_matches_exactly(cmd, "pid"))
+    if (command_matches_exactly(cmd, "id"))
     {
-        printf("pid %ld, ppid %ld\n", getpid(), getppid());
+        printf("pid %ld, ppid %ld, uid %d (%s), gid %d\n", getpid(), getppid(), getuid(), username, getgid());
+        return 1;
+    }
+    if (command_matches_exactly(cmd, "clear"))
+    {
+        fputs("\033@", stdout); // clear screen. for now, escape sequences in luna are non-standard.
         return 1;
     }
     return 0;
diff --git a/kernel/src/render/TextRenderer.cpp b/kernel/src/render/TextRenderer.cpp
index 4084c03f..d59a1a9b 100644
--- a/kernel/src/render/TextRenderer.cpp
+++ b/kernel/src/render/TextRenderer.cpp
@@ -30,7 +30,7 @@ void TextRenderer::reset()
 #pragma GCC optimize("O0")
 
 static void putchar_at_offset(
-    char c, [[maybe_unused]] uint32_t cx, [[maybe_unused]] uint32_t cy, [[maybe_unused]] Color& fg,
+    char c, uint32_t cx, uint32_t cy, [[maybe_unused]] Color& fg,
     [[maybe_unused]] Color& bg) // FIXME: Rewrite this function to actually work with foreground and background colors.
 {
     uint8_t* glyph = &font[c * 16];
@@ -46,38 +46,29 @@ static void putchar_at_offset(
     }
 }
 
+static bool g_escape_sequence = false;
+
 #pragma GCC pop_options
 
 void TextRenderer::putchar(char chr)
 {
-    switch (chr)
+    if (g_escape_sequence)
     {
-    case '\n': {
-        ypos += FONT_HEIGHT;
-        if ((ypos + FONT_HEIGHT) >= bootboot.fb_height)
+        g_escape_sequence = false;
+        switch (chr)
         {
-            memcpy((void*)bootboot.fb_ptr, (char*)bootboot.fb_ptr + (bootboot.fb_scanline * FONT_HEIGHT),
-                   bootboot.fb_size - (bootboot.fb_scanline * FONT_HEIGHT));
-            ypos -= FONT_HEIGHT;
-            framebuffer0.paint_rect(0, ypos, bootboot.fb_width, FONT_HEIGHT, Color::Black);
+        case '@':
+            reset();
+            framebuffer0.clear(Color::Black);
+            break;
+        default: break;
         }
-        xpos = 0;
-        break;
     }
-    case '\r': xpos = 0; break;
-    case '\b':
-        if (xpos != 0)
+    else
+    {
+        switch (chr)
         {
-            xpos -= FONT_WIDTH;
-            framebuffer0.paint_rect(xpos, ypos, FONT_WIDTH, FONT_HEIGHT, Color::Black);
-        }
-        break;
-    default: {
-        putchar_at_offset(chr, xpos, ypos, fgColor, bgColor);
-        xpos += FONT_WIDTH;
-        if ((xpos + FONT_WIDTH) > bootboot.fb_width)
-        {
-            xpos = 0;
+        case '\n': {
             ypos += FONT_HEIGHT;
             if ((ypos + FONT_HEIGHT) >= bootboot.fb_height)
             {
@@ -86,9 +77,36 @@ void TextRenderer::putchar(char chr)
                 ypos -= FONT_HEIGHT;
                 framebuffer0.paint_rect(0, ypos, bootboot.fb_width, FONT_HEIGHT, Color::Black);
             }
+            xpos = 0;
+            break;
+        }
+        case '\r': xpos = 0; break;
+        case '\b':
+            if (xpos != 0)
+            {
+                xpos -= FONT_WIDTH;
+                framebuffer0.paint_rect(xpos, ypos, FONT_WIDTH, FONT_HEIGHT, Color::Black);
+            }
+            break;
+        case '\033': g_escape_sequence = true; break;
+        default: {
+            putchar_at_offset(chr, xpos, ypos, fgColor, bgColor);
+            xpos += FONT_WIDTH;
+            if ((xpos + FONT_WIDTH) > bootboot.fb_width)
+            {
+                xpos = 0;
+                ypos += FONT_HEIGHT;
+                if ((ypos + FONT_HEIGHT) >= bootboot.fb_height)
+                {
+                    memcpy((void*)bootboot.fb_ptr, (char*)bootboot.fb_ptr + (bootboot.fb_scanline * FONT_HEIGHT),
+                           bootboot.fb_size - (bootboot.fb_scanline * FONT_HEIGHT));
+                    ypos -= FONT_HEIGHT;
+                    framebuffer0.paint_rect(0, ypos, bootboot.fb_width, FONT_HEIGHT, Color::Black);
+                }
+            }
+            break;
+        }
         }
-        break;
-    }
     }
 }