worktree: inline `worktree_ref()` into its only caller

We have `strbuf_worktree_ref()`, which works on a strbuf, and a wrapper
for it, `worktree_ref()` which returns a string. We even make this
wrapper available through worktree.h. But it only has a single caller,
sitting right next to it in worktree.c.

Just inline the wrapper into its only caller. This means the caller can
quite naturally reuse a single strbuf. We currently achieve something
similar by having a static strbuf in the wrapper.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

worktree.c

@@ -536,18 +536,10 @@ void strbuf_worktree_ref(const struct worktree *wt,
 	strbuf_addstr(sb, refname);
 }
 
-const char *worktree_ref(const struct worktree *wt, const char *refname)
-{
-	static struct strbuf sb = STRBUF_INIT;
-
-	strbuf_reset(&sb);
-	strbuf_worktree_ref(wt, &sb, refname);
-	return sb.buf;
-}
-
 int other_head_refs(each_ref_fn fn, void *cb_data)
 {
 	struct worktree **worktrees, **p;
+	struct strbuf refname = STRBUF_INIT;
 	int ret = 0;
 
 	worktrees = get_worktrees();
@@ -559,14 +551,17 @@ int other_head_refs(each_ref_fn fn, void *cb_data)
 		if (wt->is_current)
 			continue;
 
+		strbuf_reset(&refname);
+		strbuf_worktree_ref(wt, &refname, "HEAD");
 		if (!refs_read_ref_full(get_main_ref_store(the_repository),
-					worktree_ref(wt, "HEAD"),
+					refname.buf,
 					RESOLVE_REF_READING,
 					&oid, &flag))
-			ret = fn(worktree_ref(wt, "HEAD"), &oid, flag, cb_data);
+			ret = fn(refname.buf, &oid, flag, cb_data);
 		if (ret)
 			break;
 	}
 	free_worktrees(worktrees);
+	strbuf_release(&refname);
 	return ret;
 }

worktree.h

@@ -136,11 +136,4 @@ void strbuf_worktree_ref(const struct worktree *wt,
 			 struct strbuf *sb,
 			 const char *refname);
 
-/*
- * Return a refname suitable for access from the current ref
- * store. The result will be destroyed at the next call.
- */
-const char *worktree_ref(const struct worktree *wt,
-			 const char *refname);
-
 #endif