Refactor source code parsing and updating code into functions

- For parsing and converting source code to `String` variables, refactored into separate functions
- For removing and creating a file with updated code, refactored into separate function

Signed-off-by: Muhammad Mahad <[email protected]>

src/cli.rs

@@ -1,5 +1,7 @@
+use std::{fs, path};
+
+use anyhow::{Context, Result};
 use clap::Parser;
-use std::path;
 
 #[derive(Parser, Debug)]
 #[command(
@@ -25,6 +27,36 @@ pub struct Arguments {
     pub stderr_file: Option<path::PathBuf>,
 }
 
+pub fn parse_arguments_and_read_file(args: &Arguments) -> Result<(String, Option<String>)> {
+    //TODO: maybe to use sanitization to prevent reading files outside the project directory
+    let source_code = fs::read_to_string(&args.source_file)
+        .with_context(|| format!("could not read sourcefile `{}`", args.source_file.display()))?;
+
+    let err_file =
+        match &args.stderr_file {
+            Some(stderr_file) => Some(fs::read_to_string(stderr_file).with_context(|| {
+                format!("could not read stderr file `{}`", stderr_file.display())
+            })?),
+            None => None,
+        };
+
+    Ok((source_code, err_file))
+}
+
+pub fn update_source_code(args: &Arguments, new_code: String) -> Result<()> {
+    fs::remove_file(&args.source_file)
+        .with_context(|| format!("could not remove file `{}`", &args.source_file.display()))?;
+
+    fs::write(&args.source_file, new_code).with_context(|| {
+        format!(
+            "could not write updated code to file `{}`",
+            &args.source_file.display()
+        )
+    })?;
+
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/main.rs

@@ -1,12 +1,8 @@
-mod cli;
-mod transform;
-
 use anyhow::{Context, Result};
 use clap::Parser;
-use std::fs;
 
-const RUSTTEST_ERROR: &str = "//~^ ERROR ";
-const DG_ERROR: &str = "// { dg-error \"";
+mod cli;
+mod transform;
 
 fn main() -> Result<()> {
     try_parse()
@@ -15,8 +11,7 @@ fn main() -> Result<()> {
 fn try_parse() -> Result<()> {
     let args = cli::Arguments::parse();
 
-    let code = fs::read_to_string(&args.source_file)
-        .with_context(|| format!("could not read file `{}`", args.source_file.display()))?;
+    let (code, _stderr_code) = cli::parse_arguments_and_read_file(&args)?;
 
     let new_code = transform::transform_code(&code).with_context(|| {
         format!(
@@ -25,8 +20,7 @@ fn try_parse() -> Result<()> {
         )
     })?;
 
-    fs::remove_file(&args.source_file)?;
-    fs::write(&args.source_file, new_code.join("\n"))?;
+    cli::update_source_code(&args, new_code)?;
 
     Ok(())
 }

src/transform.rs

@@ -1,8 +1,8 @@
 use anyhow::Result;
 
 // TODO: Add more directive relative to rustc and DejaGnu
-pub const RUSTTEST_ERROR: &'static str = "//~^ ERROR ";
-pub const DG_ERROR: &'static str = "// { dg-error \"";
+pub const RUSTTEST_ERROR: &str = "//~^ ERROR ";
+pub const DG_ERROR: &str = "// { dg-error \"";
 
 /// This function takes the rust code and rust directive
 /// and returns the code with DejaGnu directive