refs: add refs_head_ref()

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pclouds

refs.c

@@ -1248,27 +1248,30 @@ int refs_rename_ref_available(struct ref_store *refs,
 	return ok;
 }
 
-int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
+int refs_head_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
 	struct object_id oid;
 	int flag;
 
-	if (submodule) {
-		if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
-			return fn("HEAD", &oid, 0, cb_data);
-
-		return 0;
-	}
-
-	if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
+	if (!refs_read_ref_full(refs, "HEAD", RESOLVE_REF_READING,
+				oid.hash, &flag))
 		return fn("HEAD", &oid, flag, cb_data);
 
 	return 0;
 }
 
+int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
+{
+	struct ref_store *refs = get_submodule_ref_store(submodule);
+
+	if (!refs)
+		return -1;
+	return refs_head_ref(refs, fn, cb_data);
+}
+
 int head_ref(each_ref_fn fn, void *cb_data)
 {
-	return head_ref_submodule(NULL, fn, cb_data);
+	return refs_head_ref(get_main_ref_store(), fn, cb_data);
 }
 
 struct ref_iterator *refs_ref_iterator_begin(

refs.h

@@ -275,6 +275,8 @@ typedef int each_ref_fn(const char *refname,
  * modifies the reference also returns a nonzero value to immediately
  * stop the iteration. Returned references are sorted.
  */
+int refs_head_ref(struct ref_store *refs,
+		  each_ref_fn fn, void *cb_data);
 int refs_for_each_ref(struct ref_store *refs,
 		      each_ref_fn fn, void *cb_data);
 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,