Rewrite build.rs

src/build.rs

@@ -1,57 +1,54 @@
 use std::env;
-use std::fs::{read_dir, File};
+use std::error::Error;
+use std::fs::{read as read_file, File};
 use std::io::ErrorKind::NotFound;
-use std::io::Read;
 use std::io::Write;
-use std::path::{Path, PathBuf};
+use std::path::Path;
 
-fn get_const_name<P: Clone + Into<PathBuf>>(p: &P) -> String {
-  let mut file_name_without_extension = p.clone().into();
-  file_name_without_extension.set_extension("");
-  String::from(
-    file_name_without_extension
-      .file_name()
-      .unwrap()
-      .to_string_lossy(),
-  )
-  .to_uppercase()
+pub fn create_static_output(
+  source_path: &Path,
+  mut target: impl Write,
+) -> Result<(), Box<dyn Error>> {
+  let const_name = source_path
+    .file_stem()
+    .ok_or("Not a filename")?
+    .to_str()
+    .ok_or("Filename is not valid unicode")?
+    .to_uppercase();
+  let content = String::from_utf8(read_file(&source_path)?)?;
+  let fence = content.chars().filter(|&c| c == '#').collect::<String>() + "#";
+
+  writeln!(
+    target,
+    "pub const {}: &str = r{1}\"{2}\"{1};",
+    const_name, fence, content
+  )?;
+  Ok(())
 }
 
-pub fn create_static_output_files(source_dir: &str) {
-  let out_dir = env::var("OUT_DIR").unwrap();
-  let dest_path = Path::new(&out_dir).join("static_files.rs");
-  let mut f = File::create(&dest_path).unwrap();
-  match read_dir(source_dir) {
+pub fn create_static_output_files(
+  source_dir: &Path,
+  dest_path: &Path,
+) -> Result<(), Box<dyn Error>> {
+  let mut f = File::create(dest_path)?;
+  match source_dir.read_dir() {
     Ok(dir_content) => {
       for maybe_dir_entry in dir_content {
-        let file_path = maybe_dir_entry.unwrap().path();
-        let mut buffer = String::new();
-        File::open(file_path.clone())
-          .unwrap()
-          .read_to_string(&mut buffer)
-          .unwrap();
-        let fence = buffer.chars().filter(|c| *c == '#').collect::<String>() + "#";
-        f.write_all(
-          format!(
-            "pub const {}: &str = r{1}\"{2}\"{1};\n",
-            get_const_name(&file_path),
-            fence,
-            buffer
-          )
-          .as_bytes(),
-        )
-        .unwrap();
+        create_static_output(&maybe_dir_entry?.path(), &mut f)?;
       }
     }
     Err(err) => {
       if err.kind() != NotFound {
-        panic!("Unexpected error: {}", err)
+        return Err(format!("Unexpected error: {}", err).into());
       }
     }
   }
+  Ok(())
 }
 
-#[allow(unused)]
-fn main() {
-  create_static_output_files("static_files");
+pub fn main() -> Result<(), Box<dyn Error>> {
+  create_static_output_files(
+    Path::new("static_files"),
+    &(Path::new(&env::var("OUT_DIR")?).join("static_files.rs")),
+  )
 }