1 files changed, 65 insertions, 7 deletions

diff --git a/src/tools/build_helper/src/git.rs b/src/tools/build_helper/src/git.rs
index dc62051cb..168633c8f 100644
--- a/src/tools/build_helper/src/git.rs
+++ b/src/tools/build_helper/src/git.rs
@@ -1,5 +1,24 @@
+use std::process::Stdio;
 use std::{path::Path, process::Command};
 
+/// Runs a command and returns the output
+fn output_result(cmd: &mut Command) -> Result<String, String> {
+    let output = match cmd.stderr(Stdio::inherit()).output() {
+        Ok(status) => status,
+        Err(e) => return Err(format!("failed to run command: {:?}: {}", cmd, e)),
+    };
+    if !output.status.success() {
+        return Err(format!(
+            "command did not execute successfully: {:?}\n\
+             expected success, got: {}\n{}",
+            cmd,
+            output.status,
+            String::from_utf8(output.stderr).map_err(|err| format!("{err:?}"))?
+        ));
+    }
+    Ok(String::from_utf8(output.stdout).map_err(|err| format!("{err:?}"))?)
+}
+
 /// Finds the remote for rust-lang/rust.
 /// For example for these remotes it will return `upstream`.
 /// ```text
@@ -14,13 +33,7 @@ pub fn get_rust_lang_rust_remote(git_dir: Option<&Path>) -> Result<String, Strin
         git.current_dir(git_dir);
     }
     git.args(["config", "--local", "--get-regex", "remote\\..*\\.url"]);
-
-    let output = git.output().map_err(|err| format!("{err:?}"))?;
-    if !output.status.success() {
-        return Err("failed to execute git config command".to_owned());
-    }
-
-    let stdout = String::from_utf8(output.stdout).map_err(|err| format!("{err:?}"))?;
+    let stdout = output_result(&mut git)?;
 
     let rust_lang_remote = stdout
         .lines()
@@ -73,3 +86,48 @@ pub fn updated_master_branch(git_dir: Option<&Path>) -> Result<String, String> {
     // We could implement smarter logic here in the future.
     Ok("origin/master".into())
 }
+
+/// Returns the files that have been modified in the current branch compared to the master branch.
+/// The `extensions` parameter can be used to filter the files by their extension.
+/// If `extensions` is empty, all files will be returned.
+pub fn get_git_modified_files(
+    git_dir: Option<&Path>,
+    extensions: &Vec<&str>,
+) -> Result<Option<Vec<String>>, String> {
+    let Ok(updated_master) = updated_master_branch(git_dir) else { return Ok(None); };
+
+    let git = || {
+        let mut git = Command::new("git");
+        if let Some(git_dir) = git_dir {
+            git.current_dir(git_dir);
+        }
+        git
+    };
+
+    let merge_base = output_result(git().arg("merge-base").arg(&updated_master).arg("HEAD"))?;
+    let files = output_result(git().arg("diff-index").arg("--name-only").arg(merge_base.trim()))?
+        .lines()
+        .map(|s| s.trim().to_owned())
+        .filter(|f| {
+            Path::new(f).extension().map_or(false, |ext| {
+                extensions.is_empty() || extensions.contains(&ext.to_str().unwrap())
+            })
+        })
+        .collect();
+    Ok(Some(files))
+}
+
+/// Returns the files that haven't been added to git yet.
+pub fn get_git_untracked_files(git_dir: Option<&Path>) -> Result<Option<Vec<String>>, String> {
+    let Ok(_updated_master) = updated_master_branch(git_dir) else { return Ok(None); };
+    let mut git = Command::new("git");
+    if let Some(git_dir) = git_dir {
+        git.current_dir(git_dir);
+    }
+
+    let files = output_result(git.arg("ls-files").arg("--others").arg("--exclude-standard"))?
+        .lines()
+        .map(|s| s.trim().to_owned())
+        .collect();
+    Ok(Some(files))
+}