refs/iterator: implement seeking for files iterators

Implement seeking for "files" iterators. As we simply use a ref-cache
iterator under the hood the implementation is straight-forward. Note
that we do not implement seeking on reflog iterators, same as with the
"reftable" backend.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

refs/files-backend.c

@@ -918,6 +918,14 @@ static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
 	return ok;
 }
 
+static int files_ref_iterator_seek(struct ref_iterator *ref_iterator,
+				   const char *prefix)
+{
+	struct files_ref_iterator *iter =
+		(struct files_ref_iterator *)ref_iterator;
+	return ref_iterator_seek(iter->iter0, prefix);
+}
+
 static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
 				   struct object_id *peeled)
 {
@@ -936,6 +944,7 @@ static void files_ref_iterator_release(struct ref_iterator *ref_iterator)
 
 static struct ref_iterator_vtable files_ref_iterator_vtable = {
 	.advance = files_ref_iterator_advance,
+	.seek = files_ref_iterator_seek,
 	.peel = files_ref_iterator_peel,
 	.release = files_ref_iterator_release,
 };
@@ -2294,6 +2303,12 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 	return ok;
 }
 
+static int files_reflog_iterator_seek(struct ref_iterator *ref_iterator UNUSED,
+				      const char *prefix UNUSED)
+{
+	BUG("ref_iterator_seek() called for reflog_iterator");
+}
+
 static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator UNUSED,
 				      struct object_id *peeled UNUSED)
 {
@@ -2309,6 +2324,7 @@ static void files_reflog_iterator_release(struct ref_iterator *ref_iterator)
 
 static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 	.advance = files_reflog_iterator_advance,
+	.seek = files_reflog_iterator_seek,
 	.peel = files_reflog_iterator_peel,
 	.release = files_reflog_iterator_release,
 };