refs: convert dwim_ref and expand_ref to struct object_id

All of the callers of these functions just pass the hash member of a
struct object_id, so convert them to use a pointer to struct object_id
directly.  Insert a check for NULL in expand_ref on a temporary basis;
this check can be removed when resolve_ref_unsafe is converted as well.

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

archive.c

@@ -371,7 +371,7 @@ static void parse_treeish_arg(const char **argv,
 		const char *colon = strchrnul(name, ':');
 		int refnamelen = colon - name;
 
-		if (!dwim_ref(name, refnamelen, oid.hash, &ref))
+		if (!dwim_ref(name, refnamelen, &oid, &ref))
 			die("no such ref: %.*s", refnamelen, name);
 		free(ref);
 	}

branch.c

@@ -264,7 +264,7 @@ void create_branch(const char *name, const char *start_name,
 		die(_("Not a valid object name: '%s'."), start_name);
 	}
 
-	switch (dwim_ref(start_name, strlen(start_name), oid.hash, &real_ref)) {
+	switch (dwim_ref(start_name, strlen(start_name), &oid, &real_ref)) {
 	case 0:
 		/* Not branching from any existing branch */
 		if (explicit_tracking)

builtin/fast-export.c

@@ -823,7 +823,7 @@ static void get_tags_and_duplicates(struct rev_cmdline_info *info)
 		if (e->flags & UNINTERESTING)
 			continue;
 
-		if (dwim_ref(e->name, strlen(e->name), oid.hash, &full_name) != 1)
+		if (dwim_ref(e->name, strlen(e->name), &oid, &full_name) != 1)
 			continue;
 
 		if (refspecs) {

builtin/log.c

@@ -975,7 +975,7 @@ static char *find_branch_name(struct rev_info *rev)
 		return NULL;
 	ref = rev->cmdline.rev[positive].name;
 	tip_oid = &rev->cmdline.rev[positive].item->oid;
-	if (dwim_ref(ref, strlen(ref), branch_oid.hash, &full_ref) &&
+	if (dwim_ref(ref, strlen(ref), &branch_oid, &full_ref) &&
 	    skip_prefix(full_ref, "refs/heads/", &v) &&
 	    !oidcmp(tip_oid, &branch_oid))
 		branch = xstrdup(v);

builtin/merge-base.c

@@ -156,7 +156,7 @@ static int handle_fork_point(int argc, const char **argv)
 	struct commit_list *bases;
 	int i, ret = 0;
 
-	switch (dwim_ref(argv[0], strlen(argv[0]), oid.hash, &refname)) {
+	switch (dwim_ref(argv[0], strlen(argv[0]), &oid, &refname)) {
 	case 0:
 		die("No such ref: '%s'", argv[0]);
 	case 1:

builtin/merge.c

@@ -454,7 +454,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
 	if (!remote_head)
 		die(_("'%s' does not point to a commit"), remote);
 
-	if (dwim_ref(remote, strlen(remote), branch_head.hash, &found_ref) > 0) {
+	if (dwim_ref(remote, strlen(remote), &branch_head, &found_ref) > 0) {
 		if (starts_with(found_ref, "refs/heads/")) {
 			strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
 				    oid_to_hex(&branch_head), remote);

builtin/rev-parse.c

@@ -133,7 +133,7 @@ static void show_rev(int type, const struct object_id *oid, const char *name)
 			struct object_id discard;
 			char *full;
 
-			switch (dwim_ref(name, strlen(name), discard.hash, &full)) {
+			switch (dwim_ref(name, strlen(name), &discard, &full)) {
 			case 0:
 				/*
 				 * Not found -- not a ref.  We could

builtin/show-branch.c

@@ -720,7 +720,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 			die(Q_("only %d entry can be shown at one time.",
 			       "only %d entries can be shown at one time.",
 			       MAX_REVS), MAX_REVS);
-		if (!dwim_ref(*av, strlen(*av), oid.hash, &ref))
+		if (!dwim_ref(*av, strlen(*av), &oid, &ref))
 			die(_("no such ref %s"), *av);
 
 		/* Has the base been specified? */

bundle.c

@@ -338,7 +338,7 @@ static int write_bundle_refs(int bundle_fd, struct rev_info *revs)
 
 		if (e->item->flags & UNINTERESTING)
 			continue;
-		if (dwim_ref(e->name, strlen(e->name), oid.hash, &ref) != 1)
+		if (dwim_ref(e->name, strlen(e->name), &oid, &ref) != 1)
 			goto skip_write_ref;
 		if (read_ref_full(e->name, RESOLVE_REF_READING, &oid, &flag))
 			flag = 0;

refs.c

@@ -456,15 +456,15 @@ static char *substitute_branch_name(const char **string, int *len)
 	return NULL;
 }
 
-int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
+int dwim_ref(const char *str, int len, struct object_id *oid, char **ref)
 {
 	char *last_branch = substitute_branch_name(&str, &len);
-	int   refs_found  = expand_ref(str, len, sha1, ref);
+	int   refs_found  = expand_ref(str, len, oid, ref);
 	free(last_branch);
 	return refs_found;
 }
 
-int expand_ref(const char *str, int len, unsigned char *sha1, char **ref)
+int expand_ref(const char *str, int len, struct object_id *oid, char **ref)
 {
 	const char **p, *r;
 	int refs_found = 0;
@@ -472,15 +472,16 @@ int expand_ref(const char *str, int len, unsigned char *sha1, char **ref)
 
 	*ref = NULL;
 	for (p = ref_rev_parse_rules; *p; p++) {
-		unsigned char sha1_from_ref[20];
+		struct object_id oid_from_ref;
-		unsigned char *this_result;
+		struct object_id *this_result;
 		int flag;
 
-		this_result = refs_found ? sha1_from_ref : sha1;
+		this_result = refs_found ? &oid_from_ref : oid;
 		strbuf_reset(&fullref);
 		strbuf_addf(&fullref, *p, len, str);
 		r = resolve_ref_unsafe(fullref.buf, RESOLVE_REF_READING,
-				       this_result, &flag);
+				       this_result ? this_result->hash : NULL,
+				       &flag);
 		if (r) {
 			if (!refs_found++)
 				*ref = xstrdup(r);

refs.h

@@ -139,8 +139,8 @@ int resolve_gitlink_ref(const char *submodule, const char *refname,
  */
 int refname_match(const char *abbrev_name, const char *full_name);
 
-int expand_ref(const char *str, int len, unsigned char *sha1, char **ref);
+int expand_ref(const char *str, int len, struct object_id *oid, char **ref);
-int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
+int dwim_ref(const char *str, int len, struct object_id *oid, char **ref);
 int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
 
 /*

remote.c

@@ -1629,7 +1629,7 @@ static void set_merge(struct branch *ret)
 		    strcmp(ret->remote_name, "."))
 			continue;
 		if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
-			     oid.hash, &ref) == 1)
+			     &oid, &ref) == 1)
 			ret->merge[i]->dst = ref;
 		else
 			ret->merge[i]->dst = xstrdup(ret->merge_name[i]);

sha1_name.c

@@ -603,7 +603,7 @@ static int get_oid_basic(const char *str, int len, struct object_id *oid,
 
 	if (len == GIT_SHA1_HEXSZ && !get_oid_hex(str, oid)) {
 		if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
-			refs_found = dwim_ref(str, len, tmp_oid.hash, &real_ref);
+			refs_found = dwim_ref(str, len, &tmp_oid, &real_ref);
 			if (refs_found > 0) {
 				warning(warn_msg, len, str);
 				if (advice_object_name_warning)
@@ -654,11 +654,11 @@ static int get_oid_basic(const char *str, int len, struct object_id *oid,
 
 	if (!len && reflog_len)
 		/* allow "@{...}" to mean the current branch reflog */
-		refs_found = dwim_ref("HEAD", 4, oid->hash, &real_ref);
+		refs_found = dwim_ref("HEAD", 4, oid, &real_ref);
 	else if (reflog_len)
 		refs_found = dwim_log(str, len, oid->hash, &real_ref);
 	else
-		refs_found = dwim_ref(str, len, oid->hash, &real_ref);
+		refs_found = dwim_ref(str, len, oid, &real_ref);
 
 	if (!refs_found)
 		return -1;

upload-pack.c

@@ -787,7 +787,7 @@ static void receive_needs(void)
 		if (skip_prefix(line, "deepen-not ", &arg)) {
 			char *ref = NULL;
 			struct object_id oid;
-			if (expand_ref(arg, strlen(arg), oid.hash, &ref) != 1)
+			if (expand_ref(arg, strlen(arg), &oid, &ref) != 1)
 				die("git upload-pack: ambiguous deepen-not: %s", line);
 			string_list_append(&deepen_not, ref);
 			free(ref);

wt-status.c

@@ -1449,7 +1449,7 @@ static void wt_status_get_detached_from(struct wt_status_state *state)
 		return;
 	}
 
-	if (dwim_ref(cb.buf.buf, cb.buf.len, oid.hash, &ref) == 1 &&
+	if (dwim_ref(cb.buf.buf, cb.buf.len, &oid, &ref) == 1 &&
 	    /* sha1 is a commit? match without further lookup */
 	    (!oidcmp(&cb.noid, &oid) ||
 	     /* perhaps sha1 is a tag, try to dereference to a commit */