Convert struct ref_array_item to struct object_id

Convert struct ref_array_item to use struct object_id by changing the
definition and applying the following semantic patch, plus the standard
object_id transforms:

@@
struct ref_array_item E1;
@@
- E1.objectname
+ E1.objectname.hash

@@
struct ref_array_item *E1;
@@
- E1->objectname
+ E1->objectname.hash

This transformation allows us to convert get_obj, which is needed to
convert parse_object_buffer.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

ref-filter.c

@@ -1366,7 +1366,7 @@ static void populate_value(struct ref_array_item *ref)
 				v->s = xstrdup(buf + 1);
 			}
 			continue;
-		} else if (!deref && grab_objectname(name, ref->objectname, v, atom)) {
+		} else if (!deref && grab_objectname(name, ref->objectname.hash, v, atom)) {
 			continue;
 		} else if (!strcmp(name, "HEAD")) {
 			const char *head;
@@ -1415,13 +1415,13 @@ static void populate_value(struct ref_array_item *ref)
 	return;
 
  need_obj:
-	buf = get_obj(ref->objectname, &obj, &size, &eaten);
+	buf = get_obj(ref->objectname.hash, &obj, &size, &eaten);
 	if (!buf)
 		die(_("missing object %s for %s"),
-		    sha1_to_hex(ref->objectname), ref->refname);
+		    oid_to_hex(&ref->objectname), ref->refname);
 	if (!obj)
 		die(_("parse_object_buffer failed on %s for %s"),
-		    sha1_to_hex(ref->objectname), ref->refname);
+		    oid_to_hex(&ref->objectname), ref->refname);
 
 	grab_values(ref->value, 0, obj, buf, size);
 	if (!eaten)
@@ -1704,7 +1704,7 @@ static struct ref_array_item *new_ref_array_item(const char *refname,
 {
 	struct ref_array_item *ref;
 	FLEX_ALLOC_STR(ref, refname, refname);
-	hashcpy(ref->objectname, objectname);
+	hashcpy(ref->objectname.hash, objectname);
 	ref->flag = flag;
 
 	return ref;

ref-filter.h

@@ -34,7 +34,7 @@ struct ref_sorting {
 };
 
 struct ref_array_item {
-	unsigned char objectname[20];
+	struct object_id objectname;
 	int flag;
 	unsigned int kind;
 	const char *symref;