Struct PackedRefs 

pub struct PackedRefs { /* private fields */ }

A one-time, in-memory snapshot of a ref store’s packed-refs file.

Bulk ref operations — notably fetch’s apply phase — resolve and write thousands of refs back-to-back. Going through resolve_ref / write_ref for each one re-reads and re-scans the entire packed-refs file on every call, making the apply O(refs × packed-refs size). On a repository with tens of thousands of packed refs that dominates the whole fetch even when no objects are transferred. Loading the file once into this snapshot and using resolve_ref_cached / write_ref_cached makes the apply linear.

The snapshot reflects packed-refs at load time. write_ref_cached may update the snapshot in place so later namespace checks in the same apply batch see loose refs without reloading the file. Otherwise treat it as read-only: stale packed data only omits refs that were loose on disk (resolved outside the snapshot) to begin with.

Implementations

impl PackedRefs

pub fn load(git_dir: &Path) -> Result<Self>

Load the packed-refs snapshot for the ref store backing git_dir (the shared common dir for linked worktrees). A missing file yields an empty snapshot; reftable repositories also yield an empty snapshot.

Errors

Returns Error::Io if packed-refs exists but cannot be read, or Error::PackedRefsUnexpectedLine when the file contains lines Git would reject.

pub fn get(&self, refname: &str) -> Option<ObjectId>

The packed value recorded for refname, if any.

pub fn has_namespace_conflict(&self, refname: &str) -> bool

Whether any packed ref name conflicts with refname as a path prefix (e.g. an existing refs/heads/x blocks creating refs/heads/x/y). Mirrors the internal packed_ref_namespace_conflict helper against the snapshot.