From ca2315aa5972d680efaabfeae0ccc94e5ced158a Mon Sep 17 00:00:00 2001
From: Austin Gill <Notgnoshi@gmail.com>
Date: Tue, 26 Mar 2024 20:05:00 -0500
Subject: [PATCH] rev-walk

---
 src/git/mod.rs | 13 ++++++++++++-
 src/main.rs    | 10 ++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/git/mod.rs b/src/git/mod.rs
index 323a754..1f64513 100644
--- a/src/git/mod.rs
+++ b/src/git/mod.rs
@@ -1,7 +1,7 @@
 use std::path::Path;
 
 use eyre::WrapErr;
-use git2::{ObjectType, Oid, Repository};
+use git2::{ObjectType, Oid, Repository, Sort};
 
 /// Fetch or find the specified repository
 ///
@@ -39,3 +39,14 @@ pub fn rev_parse(reference: &str, repo: &Repository) -> eyre::Result<Oid> {
     );
     Ok(oid)
 }
+
+pub fn rev_walk(
+    oid: Oid,
+    repo: &Repository,
+) -> eyre::Result<impl Iterator<Item = eyre::Result<Oid>> + '_> {
+    let mut revwalk = repo.revwalk().wrap_err("Could not walk repository")?;
+    revwalk.set_sorting(Sort::TIME | Sort::TOPOLOGICAL)?;
+    revwalk.push(oid)?;
+
+    Ok(revwalk.map(|r| r.wrap_err("Failed to yield next rev")))
+}
diff --git a/src/main.rs b/src/main.rs
index df9c619..f1c9e01 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -48,6 +48,16 @@ fn main() -> eyre::Result<()> {
 
     let oid = git::rev_parse(&args.reference, &repo)
         .wrap_err(format!("Failed to resolve reference {:?}", args.reference))?;
+    let oids = git::rev_walk(oid, &repo).wrap_err(format!("Failed to walk OID {oid:?}"))?;
+    for oid in oids {
+        // I'm not sure why this would happen, nor why the iterator wouldn't just return None.
+        // Maybe it's because returning None gives no context?
+        let oid = oid.wrap_err("Failed to get next OID")?;
+        let commit = repo
+            .find_commit(oid)
+            .wrap_err(format!("Failed to find commit with OID {oid:?}"))?;
+        tracing::debug!("Found commit: {:?}", commit.summary().unwrap_or("??"));
+    }
 
     Ok(())
 }