From d0ecdbef0073a5516c9b7ec56d346cf9f1febd14 Mon Sep 17 00:00:00 2001
From: natrixaeria <upezu@student.kit.edu>
Date: Sat, 9 Nov 2019 01:00:09 +0100
Subject: Create panic screen module with text buffer

---
 kernel/src/io/panic_screen.rs | 57 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 kernel/src/io/panic_screen.rs

(limited to 'kernel/src/io/panic_screen.rs')

diff --git a/kernel/src/io/panic_screen.rs b/kernel/src/io/panic_screen.rs
new file mode 100644
index 0000000..ce2c118
--- /dev/null
+++ b/kernel/src/io/panic_screen.rs
@@ -0,0 +1,57 @@
+use core::fmt::Write;
+use crate::io::vga_text::{OStream, CharState, Color};
+
+const PANIC_SCREEN_MESSAGE_BUFFER_SIZE: usize = 2048;
+
+struct TextBuffer<'a> {
+    dst: &'a mut [u8],
+    len: usize
+}
+
+impl<'a> TextBuffer<'a> {
+    fn new(dst: &'a mut [u8]) -> Self {
+        Self { dst, len: 0 }
+    }
+    fn get(&'a mut self) -> &'a mut [u8] {
+        &mut self.dst[..self.len]
+    }
+}
+
+impl<'a> core::fmt::Write for TextBuffer<'a> {
+    fn write_str(&mut self, s: &str) -> core::fmt::Result {
+        if s.len() + self.len > self.dst.len() {
+            Err(core::fmt::Error)
+        } else {
+            let s = s.as_bytes();
+            (&mut self.dst[self.len..self.len+s.len()]).clone_from_slice(s);
+            Ok(self.len += s.len())
+        }
+    }
+}
+
+pub fn show(args: Option<&core::fmt::Arguments>) {
+    let mut stderr = OStream::new();
+    stderr.set_state(CharState::from_colors(
+        Color::LightRed,
+        Color::Red,
+    ));
+    stderr.clear();
+    stderr.print(b"uff-os");
+    stderr.set_row(10);
+    stderr.set_state(CharState::from_colors(
+        Color::White,
+        Color::Red,
+    ));
+    stderr.print_centered(b"<kernel panic>");
+    stderr.set_row(14);
+    stderr.set_state(CharState::from_colors(
+        Color::Cyan,
+        Color::Red,
+    ));
+    stderr.set_centered(true);
+    let buffer: &mut [u8] = &mut [b' '; PANIC_SCREEN_MESSAGE_BUFFER_SIZE];
+    let mut tbuffer = TextBuffer::new(buffer);
+    let _ = core::fmt::write(&mut tbuffer, *args.unwrap_or(&format_args!("no panic information obtainable")));
+    stderr.print(tbuffer.get());
+    stderr.set_centered(false);
+}
-- 
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