From 2ce14e25d8f1685bd3486257cba4025587fd0fb9 Mon Sep 17 00:00:00 2001
From: Matthew Gordon <mgordon@sparkgeo.com>
Date: Thu, 12 Dec 2024 10:23:34 -0400
Subject: [PATCH] Add //#include macro

You can now include WGSL files in other WGSL files
---
 Cargo.toml           |  3 +-
 src/source_reader.rs | 79 ++++++++++++++++++++++++++++----------------
 2 files changed, 53 insertions(+), 29 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 496a3c5..fba2f74 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,4 +9,5 @@ proc-macro = true
 [dependencies]
 quote = "1.0"
 syn = "2.0.90"
-naga = { version = "23.0.0", features = ["wgsl-in"] }
\ No newline at end of file
+naga = { version = "23.0.0", features = ["wgsl-in"] }
+regex = "1.11.1"
\ No newline at end of file
diff --git a/src/source_reader.rs b/src/source_reader.rs
index 74a6fe0..0a142d7 100644
--- a/src/source_reader.rs
+++ b/src/source_reader.rs
@@ -1,55 +1,78 @@
 use {
     crate::Error,
+    regex::Regex,
     std::{
         fs,
+        io::{BufRead, BufReader},
         path::{Path, PathBuf},
     },
 };
 
-struct SourceMap {
-    filename: PathBuf,
-    offset: usize,
-    total_lines: usize,
-    insertions: Vec<SourceMap>,
+pub struct SourceMap {
+    lines: Vec<String>,
+    files: Vec<PathBuf>,
+    line_map: Vec<(usize, usize)>,
 }
 
-pub struct SourceFile {
-    source_text: String,
-    source_map: SourceMap,
-}
-
-impl SourceFile {
+impl SourceMap {
     pub fn root_filename(&self) -> &Path {
-        &self.source_map.filename
+        &self.files[0]
     }
-    pub fn full_text(&self) -> &str {
-        &self.source_text
+    pub fn full_text(&self) -> String {
+        self.lines.join("\n")
     }
 
     pub fn map_source_line_num(&self, line_num: usize) -> (&Path, usize) {
-        (&self.source_map.filename, line_num)
+        let (source_file_index, source_file_line_num) = self.line_map[line_num];
+        (&self.files[source_file_index], source_file_line_num)
     }
 
-    pub fn all_filenames(&self) -> Vec<&Path> {
-        vec![&self.source_map.filename]
+    pub fn all_filenames(&self) -> &Vec<PathBuf> {
+        &self.files
     }
 }
 
-pub fn read_source_file(source_dir: &Path, filename: &Path) -> Result<SourceFile, Error> {
-    let source_text = fs::read_to_string(&source_dir.join(filename)).map_err(|err| {
+fn ingest_file(
+    source_dir: &Path,
+    filename: &Path,
+    source_map: &mut SourceMap,
+) -> Result<(), Error> {
+    let file = fs::File::open(source_dir.join(filename)).map_err(|err| {
         Error::from_message(format!(
             "Could not open \"{}\": {}",
             &filename.as_os_str().to_string_lossy(),
             err
         ))
     })?;
-    Ok(SourceFile {
-        source_text,
-        source_map: SourceMap {
-            filename: filename.into(),
-            offset: 0,
-            total_lines: 0,
-            insertions: vec![],
-        },
-    })
+    let file_num = source_map.files.len();
+    source_map.files.push(filename.to_path_buf());
+    let var_name = Regex::new(r"^//\#include\s+(.*)\s*$");
+    let include_regex = var_name.unwrap();
+    for (line_num, line) in BufReader::new(file).lines().enumerate() {
+        let line = line.map_err(|err| {
+            Error::from_message(format!(
+                "Error reading \"{}\": {}",
+                &filename.as_os_str().to_string_lossy(),
+                err
+            ))
+        })?;
+        if let Some(captures) = include_regex.captures(&line) {
+            let nested_filename = captures.get(1).unwrap().as_str();
+            ingest_file(source_dir, Path::new(nested_filename), source_map)?;
+        } else {
+            source_map.lines.push(line);
+            source_map.line_map.push((file_num, line_num));
+        }
+    }
+    Ok(())
+}
+
+pub fn read_source_file(source_dir: &Path, filename: &Path) -> Result<SourceMap, Error> {
+    let mut source_map = SourceMap {
+        lines: vec![],
+        files: vec![],
+        line_map: vec![],
+    };
+    ingest_file(source_dir, filename, &mut source_map)?;
+    Ok(source_map)
 }