feat: add Repository::workdir_path() to easily obtain a Path for worktree items.

Author: Byron

gix/src/repository/location.rs

@@ -1,5 +1,6 @@
 use std::path::{Path, PathBuf};
 
+use crate::bstr::BStr;
 use gix_path::realpath::MAX_SYMLINKS;
 
 impl crate::Repository {
@@ -59,6 +60,16 @@ impl crate::Repository {
         self.work_tree.as_deref()
     }
 
+    /// Turn `rela_path` into a path qualified with the [`workdir()`](Self::workdir()) of this instance,
+    /// if one is available.
+    pub fn workdir_path(&self, rela_path: impl AsRef<BStr>) -> Option<PathBuf> {
+        self.workdir().and_then(|wd| {
+            gix_path::try_from_bstr(rela_path.as_ref())
+                .ok()
+                .map(|rela| wd.join(rela))
+        })
+    }
+
     // TODO: tests, respect precomposeUnicode
     /// The directory of the binary path of the current process.
     pub fn install_dir(&self) -> std::io::Result<PathBuf> {

gix/tests/gix/repository/open.rs

@@ -1,8 +1,8 @@
+use crate::util::named_subrepo_opts;
+use gix::bstr::BString;
 use std::borrow::Cow;
 use std::error::Error;
 
-use crate::util::named_subrepo_opts;
-
 #[test]
 fn on_root_with_decomposed_unicode() -> crate::Result {
     let tmp = gix_testtools::tempfile::TempDir::new()?;
@@ -47,6 +47,10 @@ fn on_root_with_decomposed_unicode() -> crate::Result {
             Cow::Owned(_),
         ));
     }
+    assert!(
+        repo.workdir_path("").expect("non-bare").is_dir(),
+        "decomposed or not, we generate a valid path given what Git would store"
+    );
 
     Ok(())
 }
@@ -129,6 +133,20 @@ fn none_bare_repo_without_index() -> crate::Result {
     )?;
     assert!(!repo.is_bare(), "worktree isn't dependent on an index file");
     assert!(repo.worktree().is_some());
+    assert_eq!(
+        repo.workdir_path(BString::from("this")).map(|p| p.is_file()),
+        Some(true)
+    );
+    #[allow(clippy::needless_borrows_for_generic_args)]
+    let actual = repo.workdir_path(&BString::from("this")).map(|p| p.is_file());
+    assert_eq!(actual, Some(true));
+    assert!(
+        repo.workdir_path("this")
+            .expect("non-bare")
+            .strip_prefix(repo.workdir().expect("non-bare"))
+            .is_ok(),
+        "this is a minimal path"
+    );
     Ok(())
 }