ch1-exp: Log and color output

Cargo.lock

@@ -2,10 +2,17 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "log"
+version = "0.4.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"
+
 [[package]]
 name = "os"
 version = "0.1.0"
 dependencies = [
+ "log",
  "sbi-rt",
 ]
 

Cargo.toml

@@ -4,4 +4,5 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+log = "0.4.22"
 sbi-rt = "0.0.3"

src/logger.rs

@@ -0,0 +1,42 @@
+use log::{Level, LevelFilter, Log};
+
+use crate::println;
+
+struct Logger;
+
+impl Log for Logger {
+    fn enabled(&self, _metadata: &log::Metadata) -> bool {
+        true
+    }
+
+    fn log(&self, record: &log::Record) {
+        if !self.enabled(record.metadata()) {
+            return;
+        }
+
+        let (color, level) = match record.level() {
+            Level::Error => (31, "ERR"),
+            Level::Warn  => (93, "WRN"),
+            Level::Info  => (34, "INF"),
+            Level::Debug => (32, "DBG"),
+            Level::Trace => (90, "TRC"),
+        };
+
+        println!("\x1b[{}m{}\x1b[0m \x1b[1m{}\x1b[0m {}", color, level, record.target(), record.args());
+    }
+
+    fn flush(&self) {}
+}
+
+pub fn init() {
+    static LOGGER: Logger = Logger;
+    log::set_logger(&LOGGER).unwrap();
+    log::set_max_level(match option_env!("LOG") {
+        Some("ERROR") => LevelFilter::Error,
+        Some("WARN")  => LevelFilter::Warn,
+        Some("INFO")  => LevelFilter::Info,
+        Some("DEBUG") => LevelFilter::Debug,
+        Some("TRACE") => LevelFilter::Trace,
+        _ => LevelFilter::Off,
+    });
+}

src/main.rs

@@ -3,24 +3,30 @@
 
 mod lang_items;
 mod sbi;
+mod logger;
 
 #[macro_use]
 mod console;
 
 use core::arch::global_asm;
+use log::{debug, error, info, trace, warn};
+
 global_asm!(include_str!("entry.asm"));
 
 #[no_mangle]
 pub fn rust_main() -> ! {
     clear_bss();
+    logger::init();
 
     sbi::console_write_byte('O' as u8);
     sbi::console_write_byte('K' as u8);
     sbi::console_write_byte('\n' as u8);
 
-    sbi::console_write("Hello World.\n".as_bytes());
-
-    println!("hello world from macro");
+    trace!("Hello World.");
+    debug!("Hello World.");
+    info!("Hello World.");
+    warn!("Hello World.");
+    error!("Hello World.");
 
     panic!("Shutdown machine!");
 }