//! # Panic module
//!
//! A panic handler that infinitely waits

use crate::{cpu,println};
use core::panic::PanicInfo;

/// # Prevent Double Faulting
///
/// An atomic operation is used to mark that
/// a fault has occurred. If it detects that
/// there was already a fault, it spins to
/// prevent a recursive faulting cycle.
fn panic_prevent_reenter() {
	use core::sync::atomic::{AtomicBool, Ordering};

	static PANIC_IN_PROGRESS: AtomicBool = AtomicBool::new(false);

	if !PANIC_IN_PROGRESS.load(Ordering::Relaxed) {
		PANIC_IN_PROGRESS.store(true, Ordering::Relaxed);
		return;
	}

	cpu::wait_forever()
}

/// # Panic handler
#[panic_handler]
fn panic(info: &PanicInfo) -> ! {
	panic_prevent_reenter();
	
	let (location, line, column) = match info.location() {
		Some(loc) => (loc.file(), loc.line(), loc.column()),
		_ => ("???",0,0),
	};

	println!("Kernel panic!\n\nPanic Location:\n\tFile: '{}', line {}, column {}\n\n{}", location, line, column, info.message().unwrap_or(&format_args!("")),);
	cpu::wait_forever()
}