Add palette backup and restore

Author: vinc

src/api/vga/mod.rs

@@ -1,17 +1,10 @@
 use crate::api::fs;
-use crate::usr::shell;
 
 pub fn graphic_mode() {
     fs::write("/dev/vga/mode", b"320x200").ok();
-
-    // TODO: Backup palette
 }
 
 pub fn text_mode() {
     fs::write("/dev/vga/mode", b"80x25").ok();
-
-    // TODO: Restore and palette backup instead of this
-    shell::exec("shell /ini/palettes/gruvbox-dark.sh").ok();
-
     print!("\x1b[2J\x1b[1;1H"); // Clear screen and move to top
 }

src/sys/vga/palette.rs

@@ -3,6 +3,9 @@ use super::*;
 use crate::api::fs::{FileIO, IO};
 
 use core::convert::TryFrom;
+use spin::Mutex;
+
+static PALETTE: Mutex<Option<Palette>> = Mutex::new(None);
 
 const DEFAULT_COLORS: [(u8, u8, u8); 16] = [
     (0x00, 0x00, 0x00), // DarkBlack
@@ -126,3 +129,13 @@ fn get_palette(i: usize) -> (u8, u8, u8) {
         WRITER.lock().palette(i)
     )
 }
+
+pub fn restore_palette() {
+    if let Some(ref palette) = *PALETTE.lock() {
+        palette.set();
+    }
+}
+
+pub fn backup_palette() {
+    *PALETTE.lock() = Some(Palette::get())
+}

src/sys/vga/screen.rs

@@ -126,14 +126,19 @@ pub fn set_80x25_mode() {
     disable_blinking();
     disable_underline();
     font::restore_font();
+    palette::restore_palette();
 }
 
 pub fn set_320x200_mode() {
+    // NOTE: Setting a graphic mode twice without going back to text mode will
+    // overwrite the backup palette.
+    palette::backup_palette();
     set_mode(&G_320_200_256);
     // TODO: Clear screen
 }
 
 pub fn set_640x480_mode() {
+    palette::backup_palette();
     set_mode(&G_640_480_16);
     // TODO: Clear screen
 }