create helper module to be embedded for the bootstrap binaries

Signed-off-by: onur-ozkan <work@onurozkan.dev>

Author: onur-ozkan

src/bootstrap/bin/_helper.rs

@@ -0,0 +1,24 @@
+/// Parses the value of the "RUSTC_VERBOSE" environment variable and returns it as a `usize`.
+/// If it was not defined, returns 0 by default.
+///
+/// Panics if "RUSTC_VERBOSE" is defined with the value that is not an unsigned integer.
+fn parse_rustc_verbose() -> usize {
+    use std::str::FromStr;
+
+    match std::env::var("RUSTC_VERBOSE") {
+        Ok(s) => usize::from_str(&s).expect("RUSTC_VERBOSE should be an integer"),
+        Err(_) => 0,
+    }
+}
+
+/// Parses the value of the "RUSTC_STAGE" environment variable and returns it as a `String`.
+///
+/// If "RUSTC_STAGE" was not set, the program will be terminated with 101.
+fn parse_rustc_stage() -> String {
+    std::env::var("RUSTC_STAGE").unwrap_or_else(|_| {
+        // Don't panic here; it's reasonable to try and run these shims directly. Give a helpful error instead.
+        eprintln!("rustc shim: fatal: RUSTC_STAGE was not set");
+        eprintln!("rustc shim: note: use `x.py build -vvv` to see all environment variables set by bootstrap");
+        exit(101);
+    })
+}

src/bootstrap/bin/rustc.rs

@@ -16,27 +16,25 @@
 //! never get replaced.
 
 include!("../dylib_util.rs");
+include!("./_helper.rs");
 
 use std::env;
 use std::path::PathBuf;
 use std::process::{exit, Child, Command};
-use std::str::FromStr;
 use std::time::Instant;
 
 fn main() {
     let args = env::args_os().skip(1).collect::<Vec<_>>();
     let arg = |name| args.windows(2).find(|args| args[0] == name).and_then(|args| args[1].to_str());
 
+    let stage = parse_rustc_stage();
+    let verbose = parse_rustc_verbose();
+
     // Detect whether or not we're a build script depending on whether --target
     // is passed (a bit janky...)
     let target = arg("--target");
     let version = args.iter().find(|w| &**w == "-vV");
 
-    let verbose = match env::var("RUSTC_VERBOSE") {
-        Ok(s) => usize::from_str(&s).expect("RUSTC_VERBOSE should be an integer"),
-        Err(_) => 0,
-    };
-
     // Use a different compiler for build scripts, since there may not yet be a
     // libstd for the real compiler to use. However, if Cargo is attempting to
     // determine the version of the compiler, the real compiler needs to be
@@ -47,12 +45,7 @@ fn main() {
     } else {
         ("RUSTC_REAL", "RUSTC_LIBDIR")
     };
-    let stage = env::var("RUSTC_STAGE").unwrap_or_else(|_| {
-        // Don't panic here; it's reasonable to try and run these shims directly. Give a helpful error instead.
-        eprintln!("rustc shim: fatal: RUSTC_STAGE was not set");
-        eprintln!("rustc shim: note: use `x.py build -vvv` to see all environment variables set by bootstrap");
-        exit(101);
-    });
+
     let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
     let on_fail = env::var_os("RUSTC_ON_FAIL").map(Command::new);
 

src/bootstrap/bin/rustdoc.rs

@@ -9,14 +9,14 @@ use std::process::{exit, Command};
 
 include!("../dylib_util.rs");
 
+include!("./_helper.rs");
+
 fn main() {
     let args = env::args_os().skip(1).collect::<Vec<_>>();
-    let stage = env::var("RUSTC_STAGE").unwrap_or_else(|_| {
-        // Don't panic here; it's reasonable to try and run these shims directly. Give a helpful error instead.
-        eprintln!("rustc shim: fatal: RUSTC_STAGE was not set");
-        eprintln!("rustc shim: note: use `x.py build -vvv` to see all environment variables set by bootstrap");
-        exit(101);
-    });
+
+    let stage = parse_rustc_stage();
+    let verbose = parse_rustc_verbose();
+
     let rustdoc = env::var_os("RUSTDOC_REAL").expect("RUSTDOC_REAL was not set");
     let libdir = env::var_os("RUSTDOC_LIBDIR").expect("RUSTDOC_LIBDIR was not set");
     let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
@@ -25,13 +25,6 @@ fn main() {
     // is passed (a bit janky...)
     let target = args.windows(2).find(|w| &*w[0] == "--target").and_then(|w| w[1].to_str());
 
-    use std::str::FromStr;
-
-    let verbose = match env::var("RUSTC_VERBOSE") {
-        Ok(s) => usize::from_str(&s).expect("RUSTC_VERBOSE should be an integer"),
-        Err(_) => 0,
-    };
-
     let mut dylib_path = dylib_path();
     dylib_path.insert(0, PathBuf::from(libdir.clone()));