ref_store: implement `refs_peel_ref()` generically

We're about to stop storing packed refs in a `ref_cache`. That means
that the only way we have left to optimize `peel_ref()` is by checking
whether the reference being peeled is the one currently being iterated
over (in `current_ref_iter`), and if so, using `ref_iterator_peel()`.
But this can be done generically; it doesn't have to be implemented
per-backend.

So implement `refs_peel_ref()` in `refs.c` and remove the `peel_ref()`
method from the refs API.

This removes the last callers of a couple of functions, so delete
them. More cleanup to come...

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/refs.c b/refs.c
index 101c107ee8..c5e6f79c77 100644
--- a/refs.c
+++ b/refs.c
@@ -1735,7 +1735,23 @@ int refs_pack_refs(struct ref_store *refs, unsigned int flags)
 int refs_peel_ref(struct ref_store *refs, const char *refname,
 		  unsigned char *sha1)
 {
-	return refs->be->peel_ref(refs, refname, sha1);
+	int flag;
+	unsigned char base[20];
+
+	if (current_ref_iter && current_ref_iter->refname == refname) {
+		struct object_id peeled;
+
+		if (ref_iterator_peel(current_ref_iter, &peeled))
+			return -1;
+		hashcpy(sha1, peeled.hash);
+		return 0;
+	}
+
+	if (refs_read_ref_full(refs, refname,
+			       RESOLVE_REF_READING, base, &flag))
+		return -1;
+
+	return peel_object(base, sha1);
 }
 
 int peel_ref(const char *refname, unsigned char *sha1)