Re: [PATCH] for-each-ref: remove multiple xstrdup() in get_short_ref()

[Jeff King <peff@peff.net>]

On Tue, Apr 07, 2009 at 09:33:19AM +0200, Bert Wesarg wrote:

> Now that get_short_ref() always return an malloced string, consolidate to
> one xstrcpy() call.

Makes sense to squash in on top of what I have. But I think it actually
is pretty easy to always return a pointer into the existing string
(patch based on current master):

---
diff --git a/builtin-for-each-ref.c b/builtin-for-each-ref.c
index 5cbb4b0..8b24a4a 100644
--- a/builtin-for-each-ref.c
+++ b/builtin-for-each-ref.c
@@ -569,7 +569,7 @@ static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
 /*
  * Shorten the refname to an non-ambiguous form
  */
-static char *get_short_ref(struct refinfo *ref)
+static const char *get_short_ref(const char *ref)
 {
 	int i;
 	static char **scanf_fmts;
@@ -598,17 +598,17 @@ static char *get_short_ref(struct refinfo *ref)
 
 	/* bail out if there are no rules */
 	if (!nr_rules)
-		return ref->refname;
+		return ref;
 
 	/* buffer for scanf result, at most ref->refname must fit */
-	short_name = xstrdup(ref->refname);
+	short_name = xstrdup(ref);
 
 	/* skip first rule, it will always match */
 	for (i = nr_rules - 1; i > 0 ; --i) {
 		int j;
 		int short_name_len;
 
-		if (1 != sscanf(ref->refname, scanf_fmts[i], short_name))
+		if (1 != sscanf(ref, scanf_fmts[i], short_name))
 			continue;
 
 		short_name_len = strlen(short_name);
@@ -637,12 +637,14 @@ static char *get_short_ref(struct refinfo *ref)
 		 * short name is non-ambiguous if all previous rules
 		 * haven't resolved to a valid ref
 		 */
-		if (j == i)
-			return short_name;
+		if (j == i) {
+			ref += strlen(ref) - strlen(short_name);
+			break;
+		}
 	}
 
 	free(short_name);
-	return ref->refname;
+	return ref;
 }
 
 
@@ -684,7 +686,7 @@ static void populate_value(struct refinfo *ref)
 			if (formatp) {
 				formatp++;
 				if (!strcmp(formatp, "short"))
-					refname = get_short_ref(ref);
+					refname = get_short_ref(ref->refname);
 				else
 					die("unknown refname format %s",
 					    formatp);