1 files changed, 35 insertions, 0 deletions
diff --git a/vendor/gix/src/head/log.rs b/vendor/gix/src/head/log.rs
new file mode 100644
index 000000000..6aa7ed1d3
--- /dev/null
+++ b/vendor/gix/src/head/log.rs
@@ -0,0 +1,35 @@
+use std::convert::TryInto;
+
+use gix_hash::ObjectId;
+
+use crate::{
+    bstr::{BString, ByteSlice},
+    Head,
+};
+
+impl<'repo> Head<'repo> {
+    /// Return a platform for obtaining iterators on the reference log associated with the `HEAD` reference.
+    pub fn log_iter(&self) -> gix_ref::file::log::iter::Platform<'static, 'repo> {
+        gix_ref::file::log::iter::Platform {
+            store: &self.repo.refs,
+            name: "HEAD".try_into().expect("HEAD is always valid"),
+            buf: Vec::new(),
+        }
+    }
+
+    /// Return a list of all branch names that were previously checked out with the first-ever checked out branch
+    /// being the first entry of the list, and the most recent is the last, along with the commit they were pointing to
+    /// at the time.
+    pub fn prior_checked_out_branches(&self) -> std::io::Result<Option<Vec<(BString, ObjectId)>>> {
+        Ok(self.log_iter().all()?.map(|log| {
+            log.filter_map(Result::ok)
+                .filter_map(|line| {
+                    line.message
+                        .strip_prefix(b"checkout: moving from ")
+                        .and_then(|from_to| from_to.find(" to ").map(|pos| &from_to[..pos]))
+                        .map(|from_branch| (from_branch.as_bstr().to_owned(), line.previous_oid()))
+                })
+                .collect()
+        }))
+    }
+}