worktree: convert struct worktree to object_id

Convert the head_sha1 member to be head_oid instead.  This is required
to convert resolve_ref_unsafe.

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

builtin/worktree.c

@@ -410,7 +410,7 @@ static void show_worktree_porcelain(struct worktree *wt)
 	if (wt->is_bare)
 		printf("bare\n");
 	else {
-		printf("HEAD %s\n", sha1_to_hex(wt->head_sha1));
+		printf("HEAD %s\n", oid_to_hex(&wt->head_oid));
 		if (wt->is_detached)
 			printf("detached\n");
 		else if (wt->head_ref)
@@ -430,7 +430,7 @@ static void show_worktree(struct worktree *wt, int path_maxlen, int abbrev_len)
 		strbuf_addstr(&sb, "(bare)");
 	else {
 		strbuf_addf(&sb, "%-*s ", abbrev_len,
-				find_unique_abbrev(wt->head_sha1, DEFAULT_ABBREV));
+				find_unique_abbrev(wt->head_oid.hash, DEFAULT_ABBREV));
 		if (wt->is_detached)
 			strbuf_addstr(&sb, "(detached HEAD)");
 		else if (wt->head_ref) {
@@ -455,7 +455,7 @@ static void measure_widths(struct worktree **wt, int *abbrev, int *maxlen)
 
 		if (path_len > *maxlen)
 			*maxlen = path_len;
-		sha1_len = strlen(find_unique_abbrev(wt[i]->head_sha1, *abbrev));
+		sha1_len = strlen(find_unique_abbrev(wt[i]->head_oid.hash, *abbrev));
 		if (sha1_len > *abbrev)
 			*abbrev = sha1_len;
 	}

worktree.c

@@ -31,7 +31,7 @@ static void add_head_info(struct worktree *wt)
 	target = refs_resolve_ref_unsafe(get_worktree_ref_store(wt),
 					 "HEAD",
 					 0,
-					 wt->head_sha1, &flags);
+					 wt->head_oid.hash, &flags);
 	if (!target)
 		return;
 

worktree.h

@@ -8,7 +8,7 @@ struct worktree {
 	char *id;
 	char *head_ref;		/* NULL if HEAD is broken or detached */
 	char *lock_reason;	/* internal use */
-	unsigned char head_sha1[20];
+	struct object_id head_oid;
 	int is_detached;
 	int is_bare;
 	int is_current;