Deduplicate getting commit object

Author: cruessler

gitoxide-core/src/repository/commit.rs

@@ -6,7 +6,7 @@ use std::{
 
 use anyhow::{anyhow, bail, Context, Result};
 use gix::{
-    bstr::{BStr, ByteSlice},
+    bstr::{BStr, BString},
     objs::commit::SIGNATURE_FIELD_NAME,
 };
 
@@ -49,10 +49,10 @@ pub fn verify(repo: gix::Repository, rev_spec: Option<&str>) -> Result<()> {
 
 pub fn sign(repo: gix::Repository, rev_spec: Option<&str>, mut out: impl std::io::Write) -> Result<()> {
     let rev_spec = rev_spec.unwrap_or("HEAD");
-    let commit = repo
+    let object = repo
         .rev_parse_single(format!("{rev_spec}^{{commit}}").as_str())?
-        .object()?
-        .into_commit();
+        .object()?;
+    let mut commit_ref = object.to_commit_ref();
 
     let mut cmd: std::process::Command = gix::command::prepare("gpg").into();
     cmd.args([
@@ -66,11 +66,7 @@ pub fn sign(repo: gix::Repository, rev_spec: Option<&str>, mut out: impl std::io
     .stdout(Stdio::piped());
     gix::trace::debug!("About to execute {cmd:?}");
     let mut child = cmd.spawn()?;
-    child
-        .stdin
-        .take()
-        .expect("to be present")
-        .write_all(commit.data.as_ref())?;
+    child.stdin.take().expect("to be present").write_all(&object.data)?;
 
     if !child.wait()?.success() {
         bail!("Command {cmd:?} failed");
@@ -83,12 +79,7 @@ pub fn sign(repo: gix::Repository, rev_spec: Option<&str>, mut out: impl std::io
         .expect("to be present")
         .read_to_end(&mut signed_data)?;
 
-    let object = repo
-        .rev_parse_single(format!("{rev_spec}^{{commit}}").as_str())?
-        .object()?;
-    let mut commit_ref = object.to_commit_ref();
-
-    let extra_header: Cow<'_, BStr> = Cow::Borrowed(signed_data.as_bstr());
+    let extra_header: Cow<'_, BStr> = Cow::Owned(BString::new(signed_data));
 
     assert!(
         !commit_ref