From 6e913b15d796dd512116a691b53ab46a584c6803 Mon Sep 17 00:00:00 2001
From: Jacob <jjh413@student.bham.ac.uk>
Date: Mon, 3 Mar 2025 15:57:16 +0000
Subject: [PATCH] Update macro to use relative working dirs, Spans

---
 kernel/src/resources/font/mod.rs |  4 ++--
 libm/src/lib.rs                  | 25 ++++++++++++++++++++-----
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/kernel/src/resources/font/mod.rs b/kernel/src/resources/font/mod.rs
index 0b27bc2..ebe52ed 100644
--- a/kernel/src/resources/font/mod.rs
+++ b/kernel/src/resources/font/mod.rs
@@ -1,9 +1,9 @@
 use libm::include_font;
 pub static FONT_SPLEEN_8X16: Font =
-    Font::new(include_font!("./kernel/resources/font/spleen-8x16.psf"));
+    Font::new(include_font!("../../../resources/font/spleen-8x16.psf"));
 
 pub static FONT_CP850_8X16: Font =
-    Font::new(include_font!("./kernel/resources/font/cp850-8x16.psf"));
+    Font::new(include_font!("../../../resources/font/cp850-8x16.psf"));
 
 // pub struct Font(pub [[u8; 16]; 512]);
 
diff --git a/libm/src/lib.rs b/libm/src/lib.rs
index 376fb0b..0c9103b 100644
--- a/libm/src/lib.rs
+++ b/libm/src/lib.rs
@@ -1,3 +1,4 @@
+#![feature(proc_macro_span)]
 #![warn(
     clippy::correctness,
     clippy::nursery,
@@ -12,18 +13,32 @@
 use std::fs::File;
 use std::io::{Read, Seek, SeekFrom};
 
-use proc_macro::TokenStream;
+use proc_macro::{Span, TokenStream};
 use quote::quote;
+use std::path::PathBuf;
 use syn::{LitStr, parse_macro_input};
-
 extern crate proc_macro;
 
 #[proc_macro]
+/// Expects the file path to be relative to the current file so this works
+/// similarly to the standard Rust include! macros.
 pub fn include_font(item: TokenStream) -> TokenStream {
-    let filename = parse_macro_input!(item as LitStr);
-    let file_path = filename.value();
+    let span = Span::call_site();
+    let source_file = span.source_file();
 
-    println!("Loading font: [{}]", file_path);
+    if !source_file.is_real() {
+        panic!(
+            "We can't handle finding files if the source file does not exist. TODO: Can we?"
+        )
+    }
+
+    let filename = parse_macro_input!(item as LitStr);
+    let source_filepath: PathBuf = source_file.path();
+    let file_path = format!(
+        "{}/{}",
+        source_filepath.parent().unwrap_or_else(|| panic!("Expected to find the calling source file in a folder like src! Got: {}", source_filepath.display())).display(),
+        filename.value()
+    );
 
     let font_bytes = match load_file(file_path) {
         Ok(bytes) => bytes,