Merge branch 'bc/object-id'

"uchar [40]" to "struct object_id" conversion continues.

* bc/object-id:
  wt-status: convert to struct object_id
  builtin/merge-base: convert to struct object_id
  Convert object iteration callbacks to struct object_id
  sha1_file: introduce an nth_packed_object_oid function
  refs: simplify parsing of reflog entries
  refs: convert each_reflog_ent_fn to struct object_id
  reflog-walk: convert struct reflog_info to struct object_id
  builtin/replace: convert to struct object_id
  Convert remaining callers of resolve_refdup to object_id
  builtin/merge: convert to struct object_id
  builtin/clone: convert to struct object_id
  builtin/branch: convert to struct object_id
  builtin/grep: convert to struct object_id
  builtin/fmt-merge-message: convert to struct object_id
  builtin/fast-export: convert to struct object_id
  builtin/describe: convert to struct object_id
  builtin/diff-tree: convert to struct object_id
  builtin/commit: convert to struct object_id
  hex: introduce parse_oid_hex

builtin/branch.c

@@ -33,7 +33,7 @@ static const char * const builtin_branch_usage[] = {
 };
 
 static const char *head;
-static unsigned char head_sha1[20];
+static struct object_id head_oid;
 
 static int branch_use_color = -1;
 static char branch_colors[][COLOR_MAXLEN] = {
@@ -118,13 +118,13 @@ static int branch_merged(int kind, const char *name,
 	if (kind == FILTER_REFS_BRANCHES) {
 		struct branch *branch = branch_get(name);
 		const char *upstream = branch_get_upstream(branch, NULL);
-		unsigned char sha1[20];
+		struct object_id oid;
 
 		if (upstream &&
 		    (reference_name = reference_name_to_free =
 		     resolve_refdup(upstream, RESOLVE_REF_READING,
-				    sha1, NULL)) != NULL)
-			reference_rev = lookup_commit_reference(sha1);
+				    oid.hash, NULL)) != NULL)
+			reference_rev = lookup_commit_reference(oid.hash);
 	}
 	if (!reference_rev)
 		reference_rev = head_rev;
@@ -154,10 +154,10 @@ static int branch_merged(int kind, const char *name,
 }
 
 static int check_branch_commit(const char *branchname, const char *refname,
-			       const unsigned char *sha1, struct commit *head_rev,
+			       const struct object_id *oid, struct commit *head_rev,
 			       int kinds, int force)
 {
-	struct commit *rev = lookup_commit_reference(sha1);
+	struct commit *rev = lookup_commit_reference(oid->hash);
 	if (!rev) {
 		error(_("Couldn't look up commit object for '%s'"), refname);
 		return -1;
@@ -184,7 +184,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 			   int quiet)
 {
 	struct commit *head_rev = NULL;
-	unsigned char sha1[20];
+	struct object_id oid;
 	char *name = NULL;
 	const char *fmt;
 	int i;
@@ -211,7 +211,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 	}
 
 	if (!force) {
-		head_rev = lookup_commit_reference(head_sha1);
+		head_rev = lookup_commit_reference(head_oid.hash);
 		if (!head_rev)
 			die(_("Couldn't look up commit object for HEAD"));
 	}
@@ -239,7 +239,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 					RESOLVE_REF_READING
 					| RESOLVE_REF_NO_RECURSE
 					| RESOLVE_REF_ALLOW_BAD_NAME,
-					sha1, &flags);
+					oid.hash, &flags);
 		if (!target) {
 			error(remote_branch
 			      ? _("remote-tracking branch '%s' not found.")
@@ -249,13 +249,13 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 		}
 
 		if (!(flags & (REF_ISSYMREF|REF_ISBROKEN)) &&
-		    check_branch_commit(bname.buf, name, sha1, head_rev, kinds,
+		    check_branch_commit(bname.buf, name, &oid, head_rev, kinds,
 					force)) {
 			ret = 1;
 			goto next;
 		}
 
-		if (delete_ref(NULL, name, is_null_sha1(sha1) ? NULL : sha1,
+		if (delete_ref(NULL, name, is_null_oid(&oid) ? NULL : oid.hash,
 			       REF_NODEREF)) {
 			error(remote_branch
 			      ? _("Error deleting remote-tracking branch '%s'")
@@ -271,7 +271,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 			       bname.buf,
 			       (flags & REF_ISBROKEN) ? "broken"
 			       : (flags & REF_ISSYMREF) ? target
-			       : find_unique_abbrev(sha1, DEFAULT_ABBREV));
+			       : find_unique_abbrev(oid.hash, DEFAULT_ABBREV));
 		}
 		delete_branch_config(bname.buf);
 
@@ -604,7 +604,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 
 	track = git_branch_track;
 
-	head = resolve_refdup("HEAD", 0, head_sha1, NULL);
+	head = resolve_refdup("HEAD", 0, head_oid.hash, NULL);
 	if (!head)
 		die(_("Failed to resolve HEAD as a valid ref."));
 	if (!strcmp(head, "HEAD"))

builtin/cat-file.c

@@ -409,20 +409,20 @@ static int batch_object_cb(const unsigned char sha1[20], void *vdata)
 	return 0;
 }
 
-static int batch_loose_object(const unsigned char *sha1,
+static int batch_loose_object(const struct object_id *oid,
 			      const char *path,
 			      void *data)
 {
-	sha1_array_append(data, sha1);
+	sha1_array_append(data, oid->hash);
 	return 0;
 }
 
-static int batch_packed_object(const unsigned char *sha1,
+static int batch_packed_object(const struct object_id *oid,
 			       struct packed_git *pack,
 			       uint32_t pos,
 			       void *data)
 {
-	sha1_array_append(data, sha1);
+	sha1_array_append(data, oid->hash);
 	return 0;
 }
 

builtin/clone.c

@@ -681,7 +681,7 @@ static void update_head(const struct ref *our, const struct ref *remote,
 
 static int checkout(int submodule_progress)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 	char *head;
 	struct lock_file *lock_file;
 	struct unpack_trees_options opts;
@@ -692,7 +692,7 @@ static int checkout(int submodule_progress)
 	if (option_no_checkout)
 		return 0;
 
-	head = resolve_refdup("HEAD", RESOLVE_REF_READING, sha1, NULL);
+	head = resolve_refdup("HEAD", RESOLVE_REF_READING, oid.hash, NULL);
 	if (!head) {
 		warning(_("remote HEAD refers to nonexistent ref, "
 			  "unable to checkout.\n"));
@@ -700,7 +700,7 @@ static int checkout(int submodule_progress)
 	}
 	if (!strcmp(head, "HEAD")) {
 		if (advice_detached_head)
-			detach_advice(sha1_to_hex(sha1));
+			detach_advice(oid_to_hex(&oid));
 	} else {
 		if (!starts_with(head, "refs/heads/"))
 			die(_("HEAD not found below refs/heads!"));
@@ -721,7 +721,7 @@ static int checkout(int submodule_progress)
 	opts.src_index = &the_index;
 	opts.dst_index = &the_index;
 
-	tree = parse_tree_indirect(sha1);
+	tree = parse_tree_indirect(oid.hash);
 	parse_tree(tree);
 	init_tree_desc(&t, tree->buffer, tree->size);
 	if (unpack_trees(1, &t, &opts) < 0)
@@ -731,7 +731,7 @@ static int checkout(int submodule_progress)
 		die(_("unable to write new index file"));
 
 	err |= run_hook_le(NULL, "post-checkout", sha1_to_hex(null_sha1),
-			   sha1_to_hex(sha1), "1", NULL);
+			   oid_to_hex(&oid), "1", NULL);
 
 	if (!err && option_recursive) {
 		struct argv_array args = ARGV_ARRAY_INIT;

builtin/commit.c

@@ -496,7 +496,7 @@ static const char *prepare_index(int argc, const char **argv, const char *prefix
 static int run_status(FILE *fp, const char *index_file, const char *prefix, int nowarn,
 		      struct wt_status *s)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 
 	if (s->relative_paths)
 		s->prefix = prefix;
@@ -509,9 +509,9 @@ static int run_status(FILE *fp, const char *index_file, const char *prefix, int
 	s->index_file = index_file;
 	s->fp = fp;
 	s->nowarn = nowarn;
-	s->is_initial = get_sha1(s->reference, sha1) ? 1 : 0;
+	s->is_initial = get_sha1(s->reference, oid.hash) ? 1 : 0;
 	if (!s->is_initial)
-		hashcpy(s->sha1_commit, sha1);
+		hashcpy(s->sha1_commit, oid.hash);
 	s->status_format = status_format;
 	s->ignore_submodule_arg = ignore_submodule_arg;
 
@@ -885,7 +885,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		commitable = run_status(s->fp, index_file, prefix, 1, s);
 		s->use_color = saved_color_setting;
 	} else {
-		unsigned char sha1[20];
+		struct object_id oid;
 		const char *parent = "HEAD";
 
 		if (!active_nr && read_cache() < 0)
@@ -894,7 +894,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		if (amend)
 			parent = "HEAD^1";
 
-		if (get_sha1(parent, sha1)) {
+		if (get_sha1(parent, oid.hash)) {
 			int i, ita_nr = 0;
 
 			for (i = 0; i < active_nr; i++)
@@ -1332,7 +1332,7 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 {
 	static struct wt_status s;
 	int fd;
-	unsigned char sha1[20];
+	struct object_id oid;
 	static struct option builtin_status_options[] = {
 		OPT__VERBOSE(&verbose, N_("be verbose")),
 		OPT_SET_INT('s', "short", &status_format,
@@ -1382,9 +1382,9 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 
 	fd = hold_locked_index(&index_lock, 0);
 
-	s.is_initial = get_sha1(s.reference, sha1) ? 1 : 0;
+	s.is_initial = get_sha1(s.reference, oid.hash) ? 1 : 0;
 	if (!s.is_initial)
-		hashcpy(s.sha1_commit, sha1);
+		hashcpy(s.sha1_commit, oid.hash);
 
 	s.ignore_submodule_arg = ignore_submodule_arg;
 	s.status_format = status_format;
@@ -1418,19 +1418,19 @@ static const char *implicit_ident_advice(void)
 
 }
 
-static void print_summary(const char *prefix, const unsigned char *sha1,
+static void print_summary(const char *prefix, const struct object_id *oid,
 			  int initial_commit)
 {
 	struct rev_info rev;
 	struct commit *commit;
 	struct strbuf format = STRBUF_INIT;
-	unsigned char junk_sha1[20];
+	struct object_id junk_oid;
 	const char *head;
 	struct pretty_print_context pctx = {0};
 	struct strbuf author_ident = STRBUF_INIT;
 	struct strbuf committer_ident = STRBUF_INIT;
 
-	commit = lookup_commit(sha1);
+	commit = lookup_commit(oid->hash);
 	if (!commit)
 		die(_("couldn't look up newly created commit"));
 	if (parse_commit(commit))
@@ -1477,7 +1477,7 @@ static void print_summary(const char *prefix, const unsigned char *sha1,
 	rev.diffopt.break_opt = 0;
 	diff_setup_done(&rev.diffopt);
 
-	head = resolve_ref_unsafe("HEAD", 0, junk_sha1, NULL);
+	head = resolve_ref_unsafe("HEAD", 0, junk_oid.hash, NULL);
 	if (!strcmp(head, "HEAD"))
 		head = _("detached HEAD");
 	else
@@ -1522,8 +1522,8 @@ static int git_commit_config(const char *k, const char *v, void *cb)
 	return git_status_config(k, v, s);
 }
 
-static int run_rewrite_hook(const unsigned char *oldsha1,
-			    const unsigned char *newsha1)
+static int run_rewrite_hook(const struct object_id *oldoid,
+			    const struct object_id *newoid)
 {
 	struct child_process proc = CHILD_PROCESS_INIT;
 	const char *argv[3];
@@ -1544,7 +1544,7 @@ static int run_rewrite_hook(const unsigned char *oldsha1,
 	code = start_command(&proc);
 	if (code)
 		return code;
-	strbuf_addf(&sb, "%s %s\n", sha1_to_hex(oldsha1), sha1_to_hex(newsha1));
+	strbuf_addf(&sb, "%s %s\n", oid_to_hex(oldoid), oid_to_hex(newoid));
 	sigchain_push(SIGPIPE, SIG_IGN);
 	write_in_full(proc.in, sb.buf, sb.len);
 	close(proc.in);
@@ -1636,7 +1636,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	struct strbuf author_ident = STRBUF_INIT;
 	const char *index_file, *reflog_msg;
 	char *nl;
-	unsigned char sha1[20];
+	struct object_id oid;
 	struct commit_list *parents = NULL;
 	struct stat statbuf;
 	struct commit *current_head = NULL;
@@ -1651,10 +1651,10 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	status_format = STATUS_FORMAT_NONE; /* Ignore status.short */
 	s.colopts = 0;
 
-	if (get_sha1("HEAD", sha1))
+	if (get_sha1("HEAD", oid.hash))
 		current_head = NULL;
 	else {
-		current_head = lookup_commit_or_die(sha1, "HEAD");
+		current_head = lookup_commit_or_die(oid.hash, "HEAD");
 		if (parse_commit(current_head))
 			die(_("could not parse HEAD commit"));
 	}
@@ -1759,7 +1759,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	}
 
 	if (commit_tree_extended(sb.buf, sb.len, active_cache_tree->sha1,
-			 parents, sha1, author_ident.buf, sign_commit, extra)) {
+			 parents, oid.hash, author_ident.buf, sign_commit, extra)) {
 		rollback_index_files();
 		die(_("failed to write commit object"));
 	}
@@ -1776,7 +1776,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
-	    ref_transaction_update(transaction, "HEAD", sha1,
+	    ref_transaction_update(transaction, "HEAD", oid.hash,
 				   current_head
 				   ? current_head->object.oid.hash : null_sha1,
 				   0, sb.buf, &err) ||
@@ -1805,13 +1805,13 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		cfg = init_copy_notes_for_rewrite("amend");
 		if (cfg) {
 			/* we are amending, so current_head is not NULL */
-			copy_note_for_rewrite(cfg, current_head->object.oid.hash, sha1);
+			copy_note_for_rewrite(cfg, current_head->object.oid.hash, oid.hash);
 			finish_copy_notes_for_rewrite(cfg, "Notes added by 'git commit --amend'");
 		}
-		run_rewrite_hook(current_head->object.oid.hash, sha1);
+		run_rewrite_hook(&current_head->object.oid, &oid);
 	}
 	if (!quiet)
-		print_summary(prefix, sha1, !current_head);
+		print_summary(prefix, &oid, !current_head);
 
 	strbuf_release(&err);
 	return 0;

builtin/count-objects.c

@@ -53,7 +53,7 @@ static void loose_garbage(const char *path)
 		report_garbage(PACKDIR_FILE_GARBAGE, path);
 }
 
-static int count_loose(const unsigned char *sha1, const char *path, void *data)
+static int count_loose(const struct object_id *oid, const char *path, void *data)
 {
 	struct stat st;
 
@@ -62,7 +62,7 @@ static int count_loose(const unsigned char *sha1, const char *path, void *data)
 	else {
 		loose_size += on_disk_bytes(st);
 		loose++;
-		if (verbose && has_sha1_pack(sha1))
+		if (verbose && has_sha1_pack(oid->hash))
 			packed_loose++;
 	}
 	return 0;

builtin/describe.c

@@ -40,11 +40,11 @@ static const char *diff_index_args[] = {
 
 struct commit_name {
 	struct hashmap_entry entry;
-	unsigned char peeled[20];
+	struct object_id peeled;
 	struct tag *tag;
 	unsigned prio:2; /* annotated tag = 2, tag = 1, head = 0 */
 	unsigned name_checked:1;
-	unsigned char sha1[20];
+	struct object_id oid;
 	char *path;
 };
 
@@ -55,17 +55,17 @@ static const char *prio_names[] = {
 static int commit_name_cmp(const struct commit_name *cn1,
 		const struct commit_name *cn2, const void *peeled)
 {
-	return hashcmp(cn1->peeled, peeled ? peeled : cn2->peeled);
+	return oidcmp(&cn1->peeled, peeled ? peeled : &cn2->peeled);
 }
 
-static inline struct commit_name *find_commit_name(const unsigned char *peeled)
+static inline struct commit_name *find_commit_name(const struct object_id *peeled)
 {
-	return hashmap_get_from_hash(&names, sha1hash(peeled), peeled);
+	return hashmap_get_from_hash(&names, sha1hash(peeled->hash), peeled->hash);
 }
 
 static int replace_name(struct commit_name *e,
 			       int prio,
-			       const unsigned char *sha1,
+			       const struct object_id *oid,
 			       struct tag **tag)
 {
 	if (!e || e->prio < prio)
@@ -78,13 +78,13 @@ static int replace_name(struct commit_name *e,
 		struct tag *t;
 
 		if (!e->tag) {
-			t = lookup_tag(e->sha1);
+			t = lookup_tag(e->oid.hash);
 			if (!t || parse_tag(t))
 				return 1;
 			e->tag = t;
 		}
 
-		t = lookup_tag(sha1);
+		t = lookup_tag(oid->hash);
 		if (!t || parse_tag(t))
 			return 0;
 		*tag = t;
@@ -97,24 +97,24 @@ static int replace_name(struct commit_name *e,
 }
 
 static void add_to_known_names(const char *path,
-			       const unsigned char *peeled,
+			       const struct object_id *peeled,
 			       int prio,
-			       const unsigned char *sha1)
+			       const struct object_id *oid)
 {
 	struct commit_name *e = find_commit_name(peeled);
 	struct tag *tag = NULL;
-	if (replace_name(e, prio, sha1, &tag)) {
+	if (replace_name(e, prio, oid, &tag)) {
 		if (!e) {
 			e = xmalloc(sizeof(struct commit_name));
-			hashcpy(e->peeled, peeled);
-			hashmap_entry_init(e, sha1hash(peeled));
+			oidcpy(&e->peeled, peeled);
+			hashmap_entry_init(e, sha1hash(peeled->hash));
 			hashmap_add(&names, e);
 			e->path = NULL;
 		}
 		e->tag = tag;
 		e->prio = prio;
 		e->name_checked = 0;
-		hashcpy(e->sha1, sha1);
+		oidcpy(&e->oid, oid);
 		free(e->path);
 		e->path = xstrdup(path);
 	}
@@ -186,7 +186,7 @@ static int get_name(const char *path, const struct object_id *oid, int flag, voi
 	else
 		prio = 0;
 
-	add_to_known_names(all ? path + 5 : path + 10, peeled.hash, prio, oid->hash);
+	add_to_known_names(all ? path + 5 : path + 10, &peeled, prio, oid);
 	return 0;
 }
 
@@ -244,7 +244,7 @@ static unsigned long finish_depth_computation(
 static void display_name(struct commit_name *n)
 {
 	if (n->prio == 2 && !n->tag) {
-		n->tag = lookup_tag(n->sha1);
+		n->tag = lookup_tag(n->oid.hash);
 		if (!n->tag || parse_tag(n->tag))
 			die(_("annotated tag %s not available"), n->path);
 	}
@@ -262,14 +262,14 @@ static void display_name(struct commit_name *n)
 		printf("%s", n->path);
 }
 
-static void show_suffix(int depth, const unsigned char *sha1)
+static void show_suffix(int depth, const struct object_id *oid)
 {
-	printf("-%d-g%s", depth, find_unique_abbrev(sha1, abbrev));
+	printf("-%d-g%s", depth, find_unique_abbrev(oid->hash, abbrev));
 }
 
 static void describe(const char *arg, int last_one)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 	struct commit *cmit, *gave_up_on = NULL;
 	struct commit_list *list;
 	struct commit_name *n;
@@ -278,20 +278,20 @@ static void describe(const char *arg, int last_one)
 	unsigned long seen_commits = 0;
 	unsigned int unannotated_cnt = 0;
 
-	if (get_sha1(arg, sha1))
+	if (get_oid(arg, &oid))
 		die(_("Not a valid object name %s"), arg);
-	cmit = lookup_commit_reference(sha1);
+	cmit = lookup_commit_reference(oid.hash);
 	if (!cmit)
 		die(_("%s is not a valid '%s' object"), arg, commit_type);
 
-	n = find_commit_name(cmit->object.oid.hash);
+	n = find_commit_name(&cmit->object.oid);
 	if (n && (tags || all || n->prio == 2)) {
 		/*
 		 * Exact match to an existing ref.
 		 */
 		display_name(n);
 		if (longformat)
-			show_suffix(0, n->tag ? n->tag->tagged->oid.hash : sha1);
+			show_suffix(0, n->tag ? &n->tag->tagged->oid : &oid);
 		if (dirty)
 			printf("%s", dirty);
 		printf("\n");
@@ -308,7 +308,7 @@ static void describe(const char *arg, int last_one)
 		struct commit *c;
 		struct commit_name *n = hashmap_iter_first(&names, &iter);
 		for (; n; n = hashmap_iter_next(&iter)) {
-			c = lookup_commit_reference_gently(n->peeled, 1);
+			c = lookup_commit_reference_gently(n->peeled.hash, 1);
 			if (c)
 				c->util = n;
 		}
@@ -412,7 +412,7 @@ static void describe(const char *arg, int last_one)
 
 	display_name(all_matches[0].name);
 	if (abbrev)
-		show_suffix(all_matches[0].depth, cmit->object.oid.hash);
+		show_suffix(all_matches[0].depth, &cmit->object.oid);
 	if (dirty)
 		printf("%s", dirty);
 	printf("\n");

builtin/diff-tree.c

@@ -7,46 +7,44 @@
 
 static struct rev_info log_tree_opt;
 
-static int diff_tree_commit_sha1(const unsigned char *sha1)
+static int diff_tree_commit_sha1(const struct object_id *oid)
 {
-	struct commit *commit = lookup_commit_reference(sha1);
+	struct commit *commit = lookup_commit_reference(oid->hash);
 	if (!commit)
 		return -1;
 	return log_tree_commit(&log_tree_opt, commit);
 }
 
 /* Diff one or more commits. */
-static int stdin_diff_commit(struct commit *commit, char *line, int len)
+static int stdin_diff_commit(struct commit *commit, const char *p)
 {
-	unsigned char sha1[20];
-	if (isspace(line[40]) && !get_sha1_hex(line+41, sha1)) {
-		/* Graft the fake parents locally to the commit */
-		int pos = 41;
-		struct commit_list **pptr;
+	struct object_id oid;
+	struct commit_list **pptr = NULL;
 
-		/* Free the real parent list */
-		free_commit_list(commit->parents);
-		commit->parents = NULL;
-		pptr = &(commit->parents);
-		while (line[pos] && !get_sha1_hex(line + pos, sha1)) {
-			struct commit *parent = lookup_commit(sha1);
-			if (parent) {
-				pptr = &commit_list_insert(parent, pptr)->next;
-			}
-			pos += 41;
+	/* Graft the fake parents locally to the commit */
+	while (isspace(*p++) && !parse_oid_hex(p, &oid, &p)) {
+		struct commit *parent = lookup_commit(oid.hash);
+		if (!pptr) {
+			/* Free the real parent list */
+			free_commit_list(commit->parents);
+			commit->parents = NULL;
+			pptr = &(commit->parents);
+		}
+		if (parent) {
+			pptr = &commit_list_insert(parent, pptr)->next;
 		}
 	}
 	return log_tree_commit(&log_tree_opt, commit);
 }
 
 /* Diff two trees. */
-static int stdin_diff_trees(struct tree *tree1, char *line, int len)
+static int stdin_diff_trees(struct tree *tree1, const char *p)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 	struct tree *tree2;
-	if (len != 82 || !isspace(line[40]) || get_sha1_hex(line + 41, sha1))
+	if (!isspace(*p++) || parse_oid_hex(p, &oid, &p) || *p)
 		return error("Need exactly two trees, separated by a space");
-	tree2 = lookup_tree(sha1);
+	tree2 = lookup_tree(oid.hash);
 	if (!tree2 || parse_tree(tree2))
 		return -1;
 	printf("%s %s\n", oid_to_hex(&tree1->object.oid),
@@ -60,23 +58,24 @@ static int stdin_diff_trees(struct tree *tree1, char *line, int len)
 static int diff_tree_stdin(char *line)
 {
 	int len = strlen(line);
-	unsigned char sha1[20];
+	struct object_id oid;
 	struct object *obj;
+	const char *p;
 
 	if (!len || line[len-1] != '\n')
 		return -1;
 	line[len-1] = 0;
-	if (get_sha1_hex(line, sha1))
+	if (parse_oid_hex(line, &oid, &p))
 		return -1;
-	obj = parse_object(sha1);
+	obj = parse_object(oid.hash);
 	if (!obj)
 		return -1;
 	if (obj->type == OBJ_COMMIT)
-		return stdin_diff_commit((struct commit *)obj, line, len);
+		return stdin_diff_commit((struct commit *)obj, p);
 	if (obj->type == OBJ_TREE)
-		return stdin_diff_trees((struct tree *)obj, line, len);
+		return stdin_diff_trees((struct tree *)obj, p);
 	error("Object %s is a %s, not a commit or tree",
-	      sha1_to_hex(sha1), typename(obj->type));
+	      oid_to_hex(&oid), typename(obj->type));
 	return -1;
 }
 
@@ -141,7 +140,7 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
 		break;
 	case 1:
 		tree1 = opt->pending.objects[0].item;
-		diff_tree_commit_sha1(tree1->oid.hash);
+		diff_tree_commit_sha1(&tree1->oid);
 		break;
 	case 2:
 		tree1 = opt->pending.objects[0].item;
@@ -164,9 +163,9 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
 			opt->diffopt.setup |= (DIFF_SETUP_USE_SIZE_CACHE |
 					       DIFF_SETUP_USE_CACHE);
 		while (fgets(line, sizeof(line), stdin)) {
-			unsigned char sha1[20];
+			struct object_id oid;
 
-			if (get_sha1_hex(line, sha1)) {
+			if (get_oid_hex(line, &oid)) {
 				fputs(line, stdout);
 				fflush(stdout);
 			}

builtin/fast-export.c

@@ -212,7 +212,7 @@ static char *anonymize_blob(unsigned long *size)
 	return strbuf_detach(&out, NULL);
 }
 
-static void export_blob(const unsigned char *sha1)
+static void export_blob(const struct object_id *oid)
 {
 	unsigned long size;
 	enum object_type type;
@@ -223,34 +223,34 @@ static void export_blob(const unsigned char *sha1)
 	if (no_data)
 		return;
 
-	if (is_null_sha1(sha1))
+	if (is_null_oid(oid))
 		return;
 
-	object = lookup_object(sha1);
+	object = lookup_object(oid->hash);
 	if (object && object->flags & SHOWN)
 		return;
 
 	if (anonymize) {
 		buf = anonymize_blob(&size);
-		object = (struct object *)lookup_blob(sha1);
+		object = (struct object *)lookup_blob(oid->hash);
 		eaten = 0;
 	} else {
-		buf = read_sha1_file(sha1, &type, &size);
+		buf = read_sha1_file(oid->hash, &type, &size);
 		if (!buf)
-			die ("Could not read blob %s", sha1_to_hex(sha1));
-		if (check_sha1_signature(sha1, buf, size, typename(type)) < 0)
-			die("sha1 mismatch in blob %s", sha1_to_hex(sha1));
-		object = parse_object_buffer(sha1, type, size, buf, &eaten);
+			die ("Could not read blob %s", oid_to_hex(oid));
+		if (check_sha1_signature(oid->hash, buf, size, typename(type)) < 0)
+			die("sha1 mismatch in blob %s", oid_to_hex(oid));
+		object = parse_object_buffer(oid->hash, type, size, buf, &eaten);
 	}
 
 	if (!object)
-		die("Could not read blob %s", sha1_to_hex(sha1));
+		die("Could not read blob %s", oid_to_hex(oid));
 
 	mark_next_object(object);
 
 	printf("blob\nmark :%"PRIu32"\ndata %lu\n", last_idnum, size);
 	if (size && fwrite(buf, size, 1, stdout) != 1)
-		die_errno ("Could not write blob '%s'", sha1_to_hex(sha1));
+		die_errno ("Could not write blob '%s'", oid_to_hex(oid));
 	printf("\n");
 
 	show_progress();
@@ -323,19 +323,19 @@ static void print_path(const char *path)
 	}
 }
 
-static void *generate_fake_sha1(const void *old, size_t *len)
+static void *generate_fake_oid(const void *old, size_t *len)
 {
 	static uint32_t counter = 1; /* avoid null sha1 */
-	unsigned char *out = xcalloc(20, 1);
-	put_be32(out + 16, counter++);
+	unsigned char *out = xcalloc(GIT_SHA1_RAWSZ, 1);
+	put_be32(out + GIT_SHA1_RAWSZ - 4, counter++);
 	return out;
 }
 
-static const unsigned char *anonymize_sha1(const unsigned char *sha1)
+static const unsigned char *anonymize_sha1(const struct object_id *oid)
 {
 	static struct hashmap sha1s;
-	size_t len = 20;
-	return anonymize_mem(&sha1s, generate_fake_sha1, sha1, &len);
+	size_t len = GIT_SHA1_RAWSZ;
+	return anonymize_mem(&sha1s, generate_fake_oid, oid, &len);
 }
 
 static void show_filemodify(struct diff_queue_struct *q,
@@ -383,7 +383,7 @@ static void show_filemodify(struct diff_queue_struct *q,
 			if (no_data || S_ISGITLINK(spec->mode))
 				printf("M %06o %s ", spec->mode,
 				       sha1_to_hex(anonymize ?
-						   anonymize_sha1(spec->oid.hash) :
+						   anonymize_sha1(&spec->oid) :
 						   spec->oid.hash));
 			else {
 				struct object *object = lookup_object(spec->oid.hash);
@@ -572,7 +572,7 @@ static void handle_commit(struct commit *commit, struct rev_info *rev)
 	/* Export the referenced blobs, and remember the marks. */
 	for (i = 0; i < diff_queued_diff.nr; i++)
 		if (!S_ISGITLINK(diff_queued_diff.queue[i]->two->mode))
-			export_blob(diff_queued_diff.queue[i]->two->oid.hash);
+			export_blob(&diff_queued_diff.queue[i]->two->oid);
 
 	refname = commit->util;
 	if (anonymize) {
@@ -797,14 +797,14 @@ static void get_tags_and_duplicates(struct rev_cmdline_info *info)
 
 	for (i = 0; i < info->nr; i++) {
 		struct rev_cmdline_entry *e = info->rev + i;
-		unsigned char sha1[20];
+		struct object_id oid;
 		struct commit *commit;
 		char *full_name;
 
 		if (e->flags & UNINTERESTING)
 			continue;
 
-		if (dwim_ref(e->name, strlen(e->name), sha1, &full_name) != 1)
+		if (dwim_ref(e->name, strlen(e->name), oid.hash, &full_name) != 1)
 			continue;
 
 		if (refspecs) {
@@ -828,7 +828,7 @@ static void get_tags_and_duplicates(struct rev_cmdline_info *info)
 		case OBJ_COMMIT:
 			break;
 		case OBJ_BLOB:
-			export_blob(commit->object.oid.hash);
+			export_blob(&commit->object.oid);
 			continue;
 		default: /* OBJ_TAG (nested tags) is already handled */
 			warning("Tag points to object of unexpected type %s, skipping.",
@@ -912,7 +912,7 @@ static void import_marks(char *input_file)
 	while (fgets(line, sizeof(line), f)) {
 		uint32_t mark;
 		char *line_end, *mark_end;
-		unsigned char sha1[20];
+		struct object_id oid;
 		struct object *object;
 		struct commit *commit;
 		enum object_type type;
@@ -924,28 +924,28 @@ static void import_marks(char *input_file)
 
 		mark = strtoumax(line + 1, &mark_end, 10);
 		if (!mark || mark_end == line + 1
-			|| *mark_end != ' ' || get_sha1_hex(mark_end + 1, sha1))
+			|| *mark_end != ' ' || get_oid_hex(mark_end + 1, &oid))
 			die("corrupt mark line: %s", line);
 
 		if (last_idnum < mark)
 			last_idnum = mark;
 
-		type = sha1_object_info(sha1, NULL);
+		type = sha1_object_info(oid.hash, NULL);
 		if (type < 0)
-			die("object not found: %s", sha1_to_hex(sha1));
+			die("object not found: %s", oid_to_hex(&oid));
 
 		if (type != OBJ_COMMIT)
 			/* only commits */
 			continue;
 
-		commit = lookup_commit(sha1);
+		commit = lookup_commit(oid.hash);
 		if (!commit)
-			die("not a commit? can't happen: %s", sha1_to_hex(sha1));
+			die("not a commit? can't happen: %s", oid_to_hex(&oid));
 
 		object = &commit->object;
 
 		if (object->flags & SHOWN)
-			error("Object %s already has a mark", sha1_to_hex(sha1));
+			error("Object %s already has a mark", oid_to_hex(&oid));
 
 		mark_object(object, mark);
 

builtin/fmt-merge-msg.c

@@ -41,7 +41,7 @@ struct src_data {
 };
 
 struct origin_data {
-	unsigned char sha1[20];
+	struct object_id oid;
 	unsigned is_local_branch:1;
 };
 
@@ -59,8 +59,8 @@ static struct string_list origins = STRING_LIST_INIT_DUP;
 struct merge_parents {
 	int alloc, nr;
 	struct merge_parent {
-		unsigned char given[20];
-		unsigned char commit[20];
+		struct object_id given;
+		struct object_id commit;
 		unsigned char used;
 	} *item;
 };
@@ -70,14 +70,14 @@ struct merge_parents {
  * hundreds of heads at a time anyway.
  */
 static struct merge_parent *find_merge_parent(struct merge_parents *table,
-					      unsigned char *given,
-					      unsigned char *commit)
+					      struct object_id *given,
+					      struct object_id *commit)
 {
 	int i;
 	for (i = 0; i < table->nr; i++) {
-		if (given && hashcmp(table->item[i].given, given))
+		if (given && oidcmp(&table->item[i].given, given))
 			continue;
-		if (commit && hashcmp(table->item[i].commit, commit))
+		if (commit && oidcmp(&table->item[i].commit, commit))
 			continue;
 		return &table->item[i];
 	}
@@ -85,14 +85,14 @@ static struct merge_parent *find_merge_parent(struct merge_parents *table,
 }
 
 static void add_merge_parent(struct merge_parents *table,
-			     unsigned char *given,
-			     unsigned char *commit)
+			     struct object_id *given,
+			     struct object_id *commit)
 {
 	if (table->nr && find_merge_parent(table, given, commit))
 		return;
 	ALLOC_GROW(table->item, table->nr + 1, table->alloc);
-	hashcpy(table->item[table->nr].given, given);
-	hashcpy(table->item[table->nr].commit, commit);
+	oidcpy(&table->item[table->nr].given, given);
+	oidcpy(&table->item[table->nr].commit, commit);
 	table->item[table->nr].used = 0;
 	table->nr++;
 }
@@ -106,30 +106,30 @@ static int handle_line(char *line, struct merge_parents *merge_parents)
 	struct src_data *src_data;
 	struct string_list_item *item;
 	int pulling_head = 0;
-	unsigned char sha1[20];
+	struct object_id oid;
 
-	if (len < 43 || line[40] != '\t')
+	if (len < GIT_SHA1_HEXSZ + 3 || line[GIT_SHA1_HEXSZ] != '\t')
 		return 1;
 
-	if (starts_with(line + 41, "not-for-merge"))
+	if (starts_with(line + GIT_SHA1_HEXSZ + 1, "not-for-merge"))
 		return 0;
 
-	if (line[41] != '\t')
+	if (line[GIT_SHA1_HEXSZ + 1] != '\t')
 		return 2;
 
-	i = get_sha1_hex(line, sha1);
+	i = get_oid_hex(line, &oid);
 	if (i)
 		return 3;
 
-	if (!find_merge_parent(merge_parents, sha1, NULL))
+	if (!find_merge_parent(merge_parents, &oid, NULL))
 		return 0; /* subsumed by other parents */
 
 	origin_data = xcalloc(1, sizeof(struct origin_data));
-	hashcpy(origin_data->sha1, sha1);
+	oidcpy(&origin_data->oid, &oid);
 
 	if (line[len - 1] == '\n')
 		line[len - 1] = 0;
-	line += 42;
+	line += GIT_SHA1_HEXSZ + 2;
 
 	/*
 	 * At this point, line points at the beginning of comment e.g.
@@ -338,10 +338,10 @@ static void shortlog(const char *name,
 	struct string_list committers = STRING_LIST_INIT_DUP;
 	int flags = UNINTERESTING | TREESAME | SEEN | SHOWN | ADDED;
 	struct strbuf sb = STRBUF_INIT;
-	const unsigned char *sha1 = origin_data->sha1;
+	const struct object_id *oid = &origin_data->oid;
 	int limit = opts->shortlog_len;
 
-	branch = deref_tag(parse_object(sha1), sha1_to_hex(sha1), 40);
+	branch = deref_tag(parse_object(oid->hash), oid_to_hex(oid), GIT_SHA1_HEXSZ);
 	if (!branch || branch->type != OBJ_COMMIT)
 		return;
 
@@ -531,7 +531,7 @@ static void fmt_merge_msg_sigs(struct strbuf *out)
 }
 
 static void find_merge_parents(struct merge_parents *result,
-			       struct strbuf *in, unsigned char *head)
+			       struct strbuf *in, struct object_id *head)
 {
 	struct commit_list *parents;
 	struct commit *head_commit;
@@ -542,31 +542,31 @@ static void find_merge_parents(struct merge_parents *result,
 		int len;
 		char *p = in->buf + pos;
 		char *newline = strchr(p, '\n');
-		unsigned char sha1[20];
+		struct object_id oid;
 		struct commit *parent;
 		struct object *obj;
 
 		len = newline ? newline - p : strlen(p);
 		pos += len + !!newline;
 
-		if (len < 43 ||
-		    get_sha1_hex(p, sha1) ||
-		    p[40] != '\t' ||
-		    p[41] != '\t')
+		if (len < GIT_SHA1_HEXSZ + 3 ||
+		    get_oid_hex(p, &oid) ||
+		    p[GIT_SHA1_HEXSZ] != '\t' ||
+		    p[GIT_SHA1_HEXSZ + 1] != '\t')
 			continue; /* skip not-for-merge */
 		/*
 		 * Do not use get_merge_parent() here; we do not have
 		 * "name" here and we do not want to contaminate its
 		 * util field yet.
 		 */
-		obj = parse_object(sha1);
+		obj = parse_object(oid.hash);
 		parent = (struct commit *)peel_to_type(NULL, 0, obj, OBJ_COMMIT);
 		if (!parent)
 			continue;
 		commit_list_insert(parent, &parents);
-		add_merge_parent(result, obj->oid.hash, parent->object.oid.hash);
+		add_merge_parent(result, &obj->oid, &parent->object.oid);
 	}
-	head_commit = lookup_commit(head);
+	head_commit = lookup_commit(head->hash);
 	if (head_commit)
 		commit_list_insert(head_commit, &parents);
 	parents = reduce_heads(parents);
@@ -574,7 +574,7 @@ static void find_merge_parents(struct merge_parents *result,
 	while (parents) {
 		struct commit *cmit = pop_commit(&parents);
 		for (i = 0; i < result->nr; i++)
-			if (!hashcmp(result->item[i].commit, cmit->object.oid.hash))
+			if (!oidcmp(&result->item[i].commit, &cmit->object.oid))
 				result->item[i].used = 1;
 	}
 
@@ -592,7 +592,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 		  struct fmt_merge_msg_opts *opts)
 {
 	int i = 0, pos = 0;
-	unsigned char head_sha1[20];
+	struct object_id head_oid;
 	const char *current_branch;
 	void *current_branch_to_free;
 	struct merge_parents merge_parents;
@@ -601,13 +601,13 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 
 	/* get current branch */
 	current_branch = current_branch_to_free =
-		resolve_refdup("HEAD", RESOLVE_REF_READING, head_sha1, NULL);
+		resolve_refdup("HEAD", RESOLVE_REF_READING, head_oid.hash, NULL);
 	if (!current_branch)
 		die("No current branch");
 	if (starts_with(current_branch, "refs/heads/"))
 		current_branch += 11;
 
-	find_merge_parents(&merge_parents, in, head_sha1);
+	find_merge_parents(&merge_parents, in, &head_oid);
 
 	/* get a line */
 	while (pos < in->len) {
@@ -633,7 +633,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 		struct commit *head;
 		struct rev_info rev;
 
-		head = lookup_commit_or_die(head_sha1, "HEAD");
+		head = lookup_commit_or_die(head_oid.hash, "HEAD");
 		init_revisions(&rev, NULL);
 		rev.commit_format = CMIT_FMT_ONELINE;
 		rev.ignore_merges = 1;

builtin/fsck.c

@@ -396,13 +396,13 @@ static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
 
 static int default_refs;
 
-static void fsck_handle_reflog_sha1(const char *refname, unsigned char *sha1,
+static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
 	unsigned long timestamp)
 {
 	struct object *obj;
 
-	if (!is_null_sha1(sha1)) {
-		obj = lookup_object(sha1);
+	if (!is_null_oid(oid)) {
+		obj = lookup_object(oid->hash);
 		if (obj && (obj->flags & HAS_OBJ)) {
 			if (timestamp && name_objects)
 				add_decoration(fsck_walk_options.object_names,
@@ -411,13 +411,13 @@ static void fsck_handle_reflog_sha1(const char *refname, unsigned char *sha1,
 			obj->used = 1;
 			mark_object_reachable(obj);
 		} else {
-			error("%s: invalid reflog entry %s", refname, sha1_to_hex(sha1));
+			error("%s: invalid reflog entry %s", refname, oid_to_hex(oid));
 			errors_found |= ERROR_REACHABLE;
 		}
 	}
 }
 
-static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
+static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid,
 		const char *email, unsigned long timestamp, int tz,
 		const char *message, void *cb_data)
 {
@@ -425,10 +425,10 @@ static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 
 	if (verbose)
 		fprintf(stderr, "Checking reflog %s->%s\n",
-			sha1_to_hex(osha1), sha1_to_hex(nsha1));
+			oid_to_hex(ooid), oid_to_hex(noid));
 
-	fsck_handle_reflog_sha1(refname, osha1, 0);
-	fsck_handle_reflog_sha1(refname, nsha1, timestamp);
+	fsck_handle_reflog_oid(refname, ooid, 0);
+	fsck_handle_reflog_oid(refname, noid, timestamp);
 	return 0;
 }
 
@@ -491,7 +491,7 @@ static void get_default_heads(void)
 	}
 }
 
-static struct object *parse_loose_object(const unsigned char *sha1,
+static struct object *parse_loose_object(const struct object_id *oid,
 					 const char *path)
 {
 	struct object *obj;
@@ -500,27 +500,27 @@ static struct object *parse_loose_object(const unsigned char *sha1,
 	unsigned long size;
 	int eaten;
 
-	if (read_loose_object(path, sha1, &type, &size, &contents) < 0)
+	if (read_loose_object(path, oid->hash, &type, &size, &contents) < 0)
 		return NULL;
 
 	if (!contents && type != OBJ_BLOB)
 		die("BUG: read_loose_object streamed a non-blob");
 
-	obj = parse_object_buffer(sha1, type, size, contents, &eaten);
+	obj = parse_object_buffer(oid->hash, type, size, contents, &eaten);
 
 	if (!eaten)
 		free(contents);
 	return obj;
 }
 
-static int fsck_loose(const unsigned char *sha1, const char *path, void *data)
+static int fsck_loose(const struct object_id *oid, const char *path, void *data)
 {
-	struct object *obj = parse_loose_object(sha1, path);
+	struct object *obj = parse_loose_object(oid, path);
 
 	if (!obj) {
 		errors_found |= ERROR_OBJECT;
 		error("%s: object corrupt or missing: %s",
-		      sha1_to_hex(sha1), path);
+		      oid_to_hex(oid), path);
 		return 0; /* keep checking other objects */
 	}
 
@@ -619,26 +619,26 @@ static int fsck_cache_tree(struct cache_tree *it)
 	return err;
 }
 
-static void mark_object_for_connectivity(const unsigned char *sha1)
+static void mark_object_for_connectivity(const struct object_id *oid)
 {
-	struct object *obj = lookup_unknown_object(sha1);
+	struct object *obj = lookup_unknown_object(oid->hash);
 	obj->flags |= HAS_OBJ;
 }
 
-static int mark_loose_for_connectivity(const unsigned char *sha1,
+static int mark_loose_for_connectivity(const struct object_id *oid,
 				       const char *path,
 				       void *data)
 {
-	mark_object_for_connectivity(sha1);
+	mark_object_for_connectivity(oid);
 	return 0;
 }
 
-static int mark_packed_for_connectivity(const unsigned char *sha1,
+static int mark_packed_for_connectivity(const struct object_id *oid,
 					struct packed_git *pack,
 					uint32_t pos,
 					void *data)
 {
-	mark_object_for_connectivity(sha1);
+	mark_object_for_connectivity(oid);
 	return 0;
 }
 

builtin/grep.c

@@ -294,17 +294,17 @@ static int grep_cmd_config(const char *var, const char *value, void *cb)
 	return st;
 }
 
-static void *lock_and_read_sha1_file(const unsigned char *sha1, enum object_type *type, unsigned long *size)
+static void *lock_and_read_oid_file(const struct object_id *oid, enum object_type *type, unsigned long *size)
 {
 	void *data;
 
 	grep_read_lock();
-	data = read_sha1_file(sha1, type, size);
+	data = read_sha1_file(oid->hash, type, size);
 	grep_read_unlock();
 	return data;
 }
 
-static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1,
+static int grep_oid(struct grep_opt *opt, const struct object_id *oid,
 		     const char *filename, int tree_name_len,
 		     const char *path)
 {
@@ -323,7 +323,7 @@ static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1,
 
 #ifndef NO_PTHREADS
 	if (num_threads) {
-		add_work(opt, GREP_SOURCE_SHA1, pathbuf.buf, path, sha1);
+		add_work(opt, GREP_SOURCE_SHA1, pathbuf.buf, path, oid);
 		strbuf_release(&pathbuf);
 		return 0;
 	} else
@@ -332,7 +332,7 @@ static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1,
 		struct grep_source gs;
 		int hit;
 
-		grep_source_init(&gs, GREP_SOURCE_SHA1, pathbuf.buf, path, sha1);
+		grep_source_init(&gs, GREP_SOURCE_SHA1, pathbuf.buf, path, oid);
 		strbuf_release(&pathbuf);
 		hit = grep_source(opt, &gs);
 
@@ -690,7 +690,7 @@ static int grep_cache(struct grep_opt *opt, const struct pathspec *pathspec,
 			    ce_skip_worktree(ce)) {
 				if (ce_stage(ce) || ce_intent_to_add(ce))
 					continue;
-				hit |= grep_sha1(opt, ce->oid.hash, ce->name,
+				hit |= grep_oid(opt, &ce->oid, ce->name,
 						 0, ce->name);
 			} else {
 				hit |= grep_file(opt, ce->name);
@@ -750,7 +750,7 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 		strbuf_add(base, entry.path, te_len);
 
 		if (S_ISREG(entry.mode)) {
-			hit |= grep_sha1(opt, entry.oid->hash, base->buf, tn_len,
+			hit |= grep_oid(opt, entry.oid, base->buf, tn_len,
 					 check_attr ? base->buf + tn_len : NULL);
 		} else if (S_ISDIR(entry.mode)) {
 			enum object_type type;
@@ -758,7 +758,7 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 			void *data;
 			unsigned long size;
 
-			data = lock_and_read_sha1_file(entry.oid->hash, &type, &size);
+			data = lock_and_read_oid_file(entry.oid, &type, &size);
 			if (!data)
 				die(_("unable to read tree (%s)"),
 				    oid_to_hex(entry.oid));
@@ -787,7 +787,7 @@ static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
 		       struct object *obj, const char *name, const char *path)
 {
 	if (obj->type == OBJ_BLOB)
-		return grep_sha1(opt, obj->oid.hash, name, 0, path);
+		return grep_oid(opt, &obj->oid, name, 0, path);
 	if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
 		struct tree_desc tree;
 		void *data;
@@ -1169,7 +1169,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	allow_revs = use_index && !untracked;
 	for (i = 0; i < argc; i++) {
 		const char *arg = argv[i];
-		unsigned char sha1[20];
+		struct object_id oid;
 		struct object_context oc;
 		struct object *object;
 
@@ -1184,13 +1184,13 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			break;
 		}
 
-		if (get_sha1_with_context(arg, 0, sha1, &oc)) {
+		if (get_sha1_with_context(arg, 0, oid.hash, &oc)) {
 			if (seen_dashdash)
 				die(_("unable to resolve revision: %s"), arg);
 			break;
 		}
 
-		object = parse_object_or_die(sha1, arg);
+		object = parse_object_or_die(oid.hash, arg);
 		if (!seen_dashdash)
 			verify_non_filename(prefix, arg);
 		add_object_array_with_path(object, arg, &list, oc.mode, oc.path);

builtin/merge-base.c

@@ -36,12 +36,12 @@ static const char * const merge_base_usage[] = {
 
 static struct commit *get_commit_reference(const char *arg)
 {
-	unsigned char revkey[20];
+	struct object_id revkey;
 	struct commit *r;
 
-	if (get_sha1(arg, revkey))
+	if (get_oid(arg, &revkey))
 		die("Not a valid object name %s", arg);
-	r = lookup_commit_reference(revkey);
+	r = lookup_commit_reference(revkey.hash);
 	if (!r)
 		die("Not a valid commit name %s", arg);
 
@@ -113,14 +113,14 @@ struct rev_collect {
 	unsigned int initial : 1;
 };
 
-static void add_one_commit(unsigned char *sha1, struct rev_collect *revs)
+static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 {
 	struct commit *commit;
 
-	if (is_null_sha1(sha1))
+	if (is_null_oid(oid))
 		return;
 
-	commit = lookup_commit(sha1);
+	commit = lookup_commit(oid->hash);
 	if (!commit ||
 	    (commit->object.flags & TMP_MARK) ||
 	    parse_commit(commit))
@@ -131,7 +131,7 @@ static void add_one_commit(unsigned char *sha1, struct rev_collect *revs)
 	commit->object.flags |= TMP_MARK;
 }
 
-static int collect_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
+static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 				  const char *ident, unsigned long timestamp,
 				  int tz, const char *message, void *cbdata)
 {
@@ -139,15 +139,15 @@ static int collect_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 
 	if (revs->initial) {
 		revs->initial = 0;
-		add_one_commit(osha1, revs);
+		add_one_commit(ooid, revs);
 	}
-	add_one_commit(nsha1, revs);
+	add_one_commit(noid, revs);
 	return 0;
 }
 
 static int handle_fork_point(int argc, const char **argv)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 	char *refname;
 	const char *commitname;
 	struct rev_collect revs;
@@ -155,7 +155,7 @@ 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]), sha1, &refname)) {
+	switch (dwim_ref(argv[0], strlen(argv[0]), oid.hash, &refname)) {
 	case 0:
 		die("No such ref: '%s'", argv[0]);
 	case 1:
@@ -165,16 +165,16 @@ static int handle_fork_point(int argc, const char **argv)
 	}
 
 	commitname = (argc == 2) ? argv[1] : "HEAD";
-	if (get_sha1(commitname, sha1))
+	if (get_oid(commitname, &oid))
 		die("Not a valid object name: '%s'", commitname);
 
-	derived = lookup_commit_reference(sha1);
+	derived = lookup_commit_reference(oid.hash);
 	memset(&revs, 0, sizeof(revs));
 	revs.initial = 1;
 	for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
 
-	if (!revs.nr && !get_sha1(refname, sha1))
-		add_one_commit(sha1, &revs);
+	if (!revs.nr && !get_oid(refname, &oid))
+		add_one_commit(&oid, &revs);
 
 	for (i = 0; i < revs.nr; i++)
 		revs.commit[i]->object.flags &= ~TMP_MARK;

builtin/merge.c

@@ -244,7 +244,7 @@ static void drop_save(void)
 	unlink(git_path_merge_mode());
 }
 
-static int save_state(unsigned char *stash)
+static int save_state(struct object_id *stash)
 {
 	int len;
 	struct child_process cp = CHILD_PROCESS_INIT;
@@ -265,7 +265,7 @@ static int save_state(unsigned char *stash)
 	else if (!len)		/* no changes */
 		return -1;
 	strbuf_setlen(&buffer, buffer.len-1);
-	if (get_sha1(buffer.buf, stash))
+	if (get_oid(buffer.buf, stash))
 		die(_("not a valid object: %s"), buffer.buf);
 	return 0;
 }
@@ -305,18 +305,18 @@ static void reset_hard(unsigned const char *sha1, int verbose)
 		die(_("read-tree failed"));
 }
 
-static void restore_state(const unsigned char *head,
-			  const unsigned char *stash)
+static void restore_state(const struct object_id *head,
+			  const struct object_id *stash)
 {
 	struct strbuf sb = STRBUF_INIT;
 	const char *args[] = { "stash", "apply", NULL, NULL };
 
-	if (is_null_sha1(stash))
+	if (is_null_oid(stash))
 		return;
 
-	reset_hard(head, 1);
+	reset_hard(head->hash, 1);
 
-	args[2] = sha1_to_hex(stash);
+	args[2] = oid_to_hex(stash);
 
 	/*
 	 * It is OK to ignore error here, for example when there was
@@ -376,10 +376,10 @@ static void squash_message(struct commit *commit, struct commit_list *remotehead
 
 static void finish(struct commit *head_commit,
 		   struct commit_list *remoteheads,
-		   const unsigned char *new_head, const char *msg)
+		   const struct object_id *new_head, const char *msg)
 {
 	struct strbuf reflog_message = STRBUF_INIT;
-	const unsigned char *head = head_commit->object.oid.hash;
+	const struct object_id *head = &head_commit->object.oid;
 
 	if (!msg)
 		strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
@@ -397,7 +397,7 @@ static void finish(struct commit *head_commit,
 		else {
 			const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 			update_ref(reflog_message.buf, "HEAD",
-				new_head, head, 0,
+				new_head->hash, head->hash, 0,
 				UPDATE_REFS_DIE_ON_ERR);
 			/*
 			 * We ignore errors in 'gc --auto', since the
@@ -416,7 +416,7 @@ static void finish(struct commit *head_commit,
 			DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 		opts.detect_rename = DIFF_DETECT_RENAME;
 		diff_setup_done(&opts);
-		diff_tree_sha1(head, new_head, "", &opts);
+		diff_tree_sha1(head->hash, new_head->hash, "", &opts);
 		diffcore_std(&opts);
 		diff_flush(&opts);
 	}
@@ -431,7 +431,7 @@ static void finish(struct commit *head_commit,
 static void merge_name(const char *remote, struct strbuf *msg)
 {
 	struct commit *remote_head;
-	unsigned char branch_head[20];
+	struct object_id branch_head;
 	struct strbuf buf = STRBUF_INIT;
 	struct strbuf bname = STRBUF_INIT;
 	const char *ptr;
@@ -441,25 +441,25 @@ static void merge_name(const char *remote, struct strbuf *msg)
 	strbuf_branchname(&bname, remote, 0);
 	remote = bname.buf;
 
-	memset(branch_head, 0, sizeof(branch_head));
+	oidclr(&branch_head);
 	remote_head = get_merge_parent(remote);
 	if (!remote_head)
 		die(_("'%s' does not point to a commit"), remote);
 
-	if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
+	if (dwim_ref(remote, strlen(remote), branch_head.hash, &found_ref) > 0) {
 		if (starts_with(found_ref, "refs/heads/")) {
 			strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
-				    sha1_to_hex(branch_head), remote);
+				    oid_to_hex(&branch_head), remote);
 			goto cleanup;
 		}
 		if (starts_with(found_ref, "refs/tags/")) {
 			strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
-				    sha1_to_hex(branch_head), remote);
+				    oid_to_hex(&branch_head), remote);
 			goto cleanup;
 		}
 		if (starts_with(found_ref, "refs/remotes/")) {
 			strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
-				    sha1_to_hex(branch_head), remote);
+				    oid_to_hex(&branch_head), remote);
 			goto cleanup;
 		}
 	}
@@ -590,8 +590,8 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 	return git_diff_ui_config(k, v, cb);
 }
 
-static int read_tree_trivial(unsigned char *common, unsigned char *head,
-			     unsigned char *one)
+static int read_tree_trivial(struct object_id *common, struct object_id *head,
+			     struct object_id *one)
 {
 	int i, nr_trees = 0;
 	struct tree *trees[MAX_UNPACK_TREES];
@@ -606,13 +606,13 @@ static int read_tree_trivial(unsigned char *common, unsigned char *head,
 	opts.verbose_update = 1;
 	opts.trivial_merges_only = 1;
 	opts.merge = 1;
-	trees[nr_trees] = parse_tree_indirect(common);
+	trees[nr_trees] = parse_tree_indirect(common->hash);
 	if (!trees[nr_trees++])
 		return -1;
-	trees[nr_trees] = parse_tree_indirect(head);
+	trees[nr_trees] = parse_tree_indirect(head->hash);
 	if (!trees[nr_trees++])
 		return -1;
-	trees[nr_trees] = parse_tree_indirect(one);
+	trees[nr_trees] = parse_tree_indirect(one->hash);
 	if (!trees[nr_trees++])
 		return -1;
 	opts.fn = threeway_merge;
@@ -626,9 +626,9 @@ static int read_tree_trivial(unsigned char *common, unsigned char *head,
 	return 0;
 }
 
-static void write_tree_trivial(unsigned char *sha1)
+static void write_tree_trivial(struct object_id *oid)
 {
-	if (write_cache_as_tree(sha1, 0, NULL))
+	if (write_cache_as_tree(oid->hash, 0, NULL))
 		die(_("git write-tree failed to write a tree"));
 }
 
@@ -781,7 +781,7 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 
 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 {
-	unsigned char result_tree[20], result_commit[20];
+	struct object_id result_tree, result_commit;
 	struct commit_list *parents, **pptr = &parents;
 	static struct lock_file lock;
 
@@ -792,15 +792,15 @@ static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 		return error(_("Unable to write index."));
 	rollback_lock_file(&lock);
 
-	write_tree_trivial(result_tree);
+	write_tree_trivial(&result_tree);
 	printf(_("Wonderful.\n"));
 	pptr = commit_list_append(head, pptr);
 	pptr = commit_list_append(remoteheads->item, pptr);
 	prepare_to_commit(remoteheads);
-	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
-			result_commit, NULL, sign_commit))
+	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree.hash, parents,
+			result_commit.hash, NULL, sign_commit))
 		die(_("failed to write commit object"));
-	finish(head, remoteheads, result_commit, "In-index merge");
+	finish(head, remoteheads, &result_commit, "In-index merge");
 	drop_save();
 	return 0;
 }
@@ -809,12 +809,12 @@ static int finish_automerge(struct commit *head,
 			    int head_subsumed,
 			    struct commit_list *common,
 			    struct commit_list *remoteheads,
-			    unsigned char *result_tree,
+			    struct object_id *result_tree,
 			    const char *wt_strategy)
 {
 	struct commit_list *parents = NULL;
 	struct strbuf buf = STRBUF_INIT;
-	unsigned char result_commit[20];
+	struct object_id result_commit;
 
 	free_commit_list(common);
 	parents = remoteheads;
@@ -822,11 +822,11 @@ static int finish_automerge(struct commit *head,
 		commit_list_insert(head, &parents);
 	strbuf_addch(&merge_msg, '\n');
 	prepare_to_commit(remoteheads);
-	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
-			result_commit, NULL, sign_commit))
+	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree->hash, parents,
+			result_commit.hash, NULL, sign_commit))
 		die(_("failed to write commit object"));
 	strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
-	finish(head, remoteheads, result_commit, buf.buf);
+	finish(head, remoteheads, &result_commit, buf.buf);
 	strbuf_release(&buf);
 	drop_save();
 	return 0;
@@ -854,18 +854,18 @@ static int suggest_conflicts(void)
 }
 
 static struct commit *is_old_style_invocation(int argc, const char **argv,
-					      const unsigned char *head)
+					      const struct object_id *head)
 {
 	struct commit *second_token = NULL;
 	if (argc > 2) {
-		unsigned char second_sha1[20];
+		struct object_id second_oid;
 
-		if (get_sha1(argv[1], second_sha1))
+		if (get_oid(argv[1], &second_oid))
 			return NULL;
-		second_token = lookup_commit_reference_gently(second_sha1, 0);
+		second_token = lookup_commit_reference_gently(second_oid.hash, 0);
 		if (!second_token)
 			die(_("'%s' is not a commit"), argv[1]);
-		if (hashcmp(second_token->object.oid.hash, head))
+		if (oidcmp(&second_token->object.oid, head))
 			return NULL;
 	}
 	return second_token;
@@ -1038,7 +1038,7 @@ static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge
 		die_errno(_("could not close '%s'"), filename);
 
 	for (pos = 0; pos < merge_names->len; pos = npos) {
-		unsigned char sha1[20];
+		struct object_id oid;
 		char *ptr;
 		struct commit *commit;
 
@@ -1048,16 +1048,16 @@ static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge
 		else
 			npos = merge_names->len;
 
-		if (npos - pos < 40 + 2 ||
-		    get_sha1_hex(merge_names->buf + pos, sha1))
+		if (npos - pos < GIT_SHA1_HEXSZ + 2 ||
+		    get_oid_hex(merge_names->buf + pos, &oid))
 			commit = NULL; /* bad */
-		else if (memcmp(merge_names->buf + pos + 40, "\t\t", 2))
+		else if (memcmp(merge_names->buf + pos + GIT_SHA1_HEXSZ, "\t\t", 2))
 			continue; /* not-for-merge */
 		else {
-			char saved = merge_names->buf[pos + 40];
-			merge_names->buf[pos + 40] = '\0';
+			char saved = merge_names->buf[pos + GIT_SHA1_HEXSZ];
+			merge_names->buf[pos + GIT_SHA1_HEXSZ] = '\0';
 			commit = get_merge_parent(merge_names->buf + pos);
-			merge_names->buf[pos + 40] = saved;
+			merge_names->buf[pos + GIT_SHA1_HEXSZ] = saved;
 		}
 		if (!commit) {
 			if (ptr)
@@ -1117,9 +1117,7 @@ static struct commit_list *collect_parents(struct commit *head_commit,
 
 int cmd_merge(int argc, const char **argv, const char *prefix)
 {
-	unsigned char result_tree[20];
-	unsigned char stash[20];
-	unsigned char head_sha1[20];
+	struct object_id result_tree, stash, head_oid;
 	struct commit *head_commit;
 	struct strbuf buf = STRBUF_INIT;
 	const char *head_arg;
@@ -1138,13 +1136,13 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * Check if we are _not_ on a detached HEAD, i.e. if there is a
 	 * current branch.
 	 */
-	branch = branch_to_free = resolve_refdup("HEAD", 0, head_sha1, NULL);
+	branch = branch_to_free = resolve_refdup("HEAD", 0, head_oid.hash, NULL);
 	if (branch && starts_with(branch, "refs/heads/"))
 		branch += 11;
-	if (!branch || is_null_sha1(head_sha1))
+	if (!branch || is_null_oid(&head_oid))
 		head_commit = NULL;
 	else
-		head_commit = lookup_commit_or_die(head_sha1, "HEAD");
+		head_commit = lookup_commit_or_die(head_oid.hash, "HEAD");
 
 	init_diff_ui_defaults();
 	git_config(git_merge_config, NULL);
@@ -1242,7 +1240,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		 * to forbid "git merge" into a branch yet to be born.
 		 * We do the same for "git pull".
 		 */
-		unsigned char *remote_head_sha1;
+		struct object_id *remote_head_oid;
 		if (squash)
 			die(_("Squash commit into empty head not supported yet"));
 		if (fast_forward == FF_NO)
@@ -1254,9 +1252,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			die(_("%s - not something we can merge"), argv[0]);
 		if (remoteheads->next)
 			die(_("Can merge only exactly one commit into empty head"));
-		remote_head_sha1 = remoteheads->item->object.oid.hash;
-		read_empty(remote_head_sha1, 0);
-		update_ref("initial pull", "HEAD", remote_head_sha1,
+		remote_head_oid = &remoteheads->item->object.oid;
+		read_empty(remote_head_oid->hash, 0);
+		update_ref("initial pull", "HEAD", remote_head_oid->hash,
 			   NULL, 0, UPDATE_REFS_DIE_ON_ERR);
 		goto done;
 	}
@@ -1270,7 +1268,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * additional safety measure to check for it.
 	 */
 	if (!have_message &&
-	    is_old_style_invocation(argc, argv, head_commit->object.oid.hash)) {
+	    is_old_style_invocation(argc, argv, &head_commit->object.oid)) {
 		warning("old-style 'git merge <msg> HEAD <commit>' is deprecated.");
 		strbuf_addstr(&merge_msg, argv[0]);
 		head_arg = argv[1];
@@ -1422,7 +1420,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			goto done;
 		}
 
-		finish(head_commit, remoteheads, commit->object.oid.hash, msg.buf);
+		finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
 		drop_save();
 		goto done;
 	} else if (!remoteheads->next && common->next)
@@ -1441,9 +1439,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			/* See if it is really trivial. */
 			git_committer_info(IDENT_STRICT);
 			printf(_("Trying really trivial in-index merge...\n"));
-			if (!read_tree_trivial(common->item->object.oid.hash,
-					       head_commit->object.oid.hash,
-					       remoteheads->item->object.oid.hash)) {
+			if (!read_tree_trivial(&common->item->object.oid,
+					       &head_commit->object.oid,
+					       &remoteheads->item->object.oid)) {
 				ret = merge_trivial(head_commit, remoteheads);
 				goto done;
 			}
@@ -1495,14 +1493,14 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	    /*
 	     * Stash away the local changes so that we can try more than one.
 	     */
-	    save_state(stash))
-		hashclr(stash);
+	    save_state(&stash))
+		oidclr(&stash);
 
 	for (i = 0; i < use_strategies_nr; i++) {
 		int ret;
 		if (i) {
 			printf(_("Rewinding the tree to pristine...\n"));
-			restore_state(head_commit->object.oid.hash, stash);
+			restore_state(&head_commit->object.oid, &stash);
 		}
 		if (use_strategies_nr != 1)
 			printf(_("Trying merge strategy %s...\n"),
@@ -1547,7 +1545,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		}
 
 		/* Automerge succeeded. */
-		write_tree_trivial(result_tree);
+		write_tree_trivial(&result_tree);
 		automerge_was_ok = 1;
 		break;
 	}
@@ -1559,7 +1557,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	if (automerge_was_ok) {
 		ret = finish_automerge(head_commit, head_subsumed,
 				       common, remoteheads,
-				       result_tree, wt_strategy);
+				       &result_tree, wt_strategy);
 		goto done;
 	}
 
@@ -1568,7 +1566,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * it up.
 	 */
 	if (!best_strategy) {
-		restore_state(head_commit->object.oid.hash, stash);
+		restore_state(&head_commit->object.oid, &stash);
 		if (use_strategies_nr > 1)
 			fprintf(stderr,
 				_("No merge strategy handled the merge.\n"));
@@ -1581,7 +1579,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		; /* We already have its result in the working tree. */
 	else {
 		printf(_("Rewinding the tree to pristine...\n"));
-		restore_state(head_commit->object.oid.hash, stash);
+		restore_state(&head_commit->object.oid, &stash);
 		printf(_("Using the %s to prepare resolving by hand.\n"),
 			best_strategy);
 		try_merge_strategy(best_strategy, common, remoteheads,

builtin/notes.c

@@ -693,7 +693,7 @@ static int merge_abort(struct notes_merge_options *o)
 static int merge_commit(struct notes_merge_options *o)
 {
 	struct strbuf msg = STRBUF_INIT;
-	unsigned char sha1[20], parent_sha1[20];
+	struct object_id oid, parent_oid;
 	struct notes_tree *t;
 	struct commit *partial;
 	struct pretty_print_context pretty_ctx;
@@ -705,27 +705,27 @@ static int merge_commit(struct notes_merge_options *o)
 	 * and target notes ref from .git/NOTES_MERGE_REF.
 	 */
 
-	if (get_sha1("NOTES_MERGE_PARTIAL", sha1))
+	if (get_oid("NOTES_MERGE_PARTIAL", &oid))
 		die(_("failed to read ref NOTES_MERGE_PARTIAL"));
-	else if (!(partial = lookup_commit_reference(sha1)))
+	else if (!(partial = lookup_commit_reference(oid.hash)))
 		die(_("could not find commit from NOTES_MERGE_PARTIAL."));
 	else if (parse_commit(partial))
 		die(_("could not parse commit from NOTES_MERGE_PARTIAL."));
 
 	if (partial->parents)
-		hashcpy(parent_sha1, partial->parents->item->object.oid.hash);
+		oidcpy(&parent_oid, &partial->parents->item->object.oid);
 	else
-		hashclr(parent_sha1);
+		oidclr(&parent_oid);
 
 	t = xcalloc(1, sizeof(struct notes_tree));
 	init_notes(t, "NOTES_MERGE_PARTIAL", combine_notes_overwrite, 0);
 
 	o->local_ref = local_ref_to_free =
-		resolve_refdup("NOTES_MERGE_REF", 0, sha1, NULL);
+		resolve_refdup("NOTES_MERGE_REF", 0, oid.hash, NULL);
 	if (!o->local_ref)
 		die(_("failed to resolve NOTES_MERGE_REF"));
 
-	if (notes_merge_commit(o, t, partial, sha1))
+	if (notes_merge_commit(o, t, partial, oid.hash))
 		die(_("failed to finalize notes merge"));
 
 	/* Reuse existing commit message in reflog message */
@@ -733,8 +733,8 @@ static int merge_commit(struct notes_merge_options *o)
 	format_commit_message(partial, "%s", &msg, &pretty_ctx);
 	strbuf_trim(&msg);
 	strbuf_insert(&msg, 0, "notes: ", 7);
-	update_ref(msg.buf, o->local_ref, sha1,
-		   is_null_sha1(parent_sha1) ? NULL : parent_sha1,
+	update_ref(msg.buf, o->local_ref, oid.hash,
+		   is_null_oid(&parent_oid) ? NULL : parent_oid.hash,
 		   0, UPDATE_REFS_DIE_ON_ERR);
 
 	free_notes(t);

builtin/pack-objects.c

@@ -2612,17 +2612,17 @@ static void add_objects_in_unpacked_packs(struct rev_info *revs)
 	free(in_pack.array);
 }
 
-static int add_loose_object(const unsigned char *sha1, const char *path,
+static int add_loose_object(const struct object_id *oid, const char *path,
 			    void *data)
 {
-	enum object_type type = sha1_object_info(sha1, NULL);
+	enum object_type type = sha1_object_info(oid->hash, NULL);
 
 	if (type < 0) {
 		warning("loose object at %s could not be examined", path);
 		return 0;
 	}
 
-	add_object_entry(sha1, type, "", 0);
+	add_object_entry(oid->hash, type, "", 0);
 	return 0;
 }
 

builtin/prune-packed.c

@@ -19,12 +19,12 @@ static int prune_subdir(int nr, const char *path, void *data)
 	return 0;
 }
 
-static int prune_object(const unsigned char *sha1, const char *path,
+static int prune_object(const struct object_id *oid, const char *path,
 			 void *data)
 {
 	int *opts = data;
 
-	if (!has_sha1_pack(sha1))
+	if (!has_sha1_pack(oid->hash))
 		return 0;
 
 	if (*opts & PRUNE_PACKED_DRY_RUN)

builtin/prune.c

@@ -30,7 +30,7 @@ static int prune_tmp_file(const char *fullpath)
 	return 0;
 }
 
-static int prune_object(const unsigned char *sha1, const char *fullpath,
+static int prune_object(const struct object_id *oid, const char *fullpath,
 			void *data)
 {
 	struct stat st;
@@ -39,7 +39,7 @@ static int prune_object(const unsigned char *sha1, const char *fullpath,
 	 * Do we know about this object?
 	 * It must have been reachable
 	 */
-	if (lookup_object(sha1))
+	if (lookup_object(oid->hash))
 		return 0;
 
 	if (lstat(fullpath, &st)) {
@@ -50,8 +50,8 @@ static int prune_object(const unsigned char *sha1, const char *fullpath,
 	if (st.st_mtime > expire)
 		return 0;
 	if (show_only || verbose) {
-		enum object_type type = sha1_object_info(sha1, NULL);
-		printf("%s %s\n", sha1_to_hex(sha1),
+		enum object_type type = sha1_object_info(oid->hash, NULL);
+		printf("%s %s\n", oid_to_hex(oid),
 		       (type > 0) ? typename(type) : "unknown");
 	}
 	if (!show_only)

builtin/receive-pack.c

@@ -1417,7 +1417,7 @@ static void execute_commands(struct command *commands,
 {
 	struct check_connected_options opt = CHECK_CONNECTED_INIT;
 	struct command *cmd;
-	unsigned char sha1[20];
+	struct object_id oid;
 	struct iterate_data data;
 	struct async muxer;
 	int err_fd = 0;
@@ -1474,7 +1474,7 @@ static void execute_commands(struct command *commands,
 	check_aliased_updates(commands);
 
 	free(head_name_to_free);
-	head_name = head_name_to_free = resolve_refdup("HEAD", 0, sha1, NULL);
+	head_name = head_name_to_free = resolve_refdup("HEAD", 0, oid.hash, NULL);
 
 	if (use_atomic)
 		execute_commands_atomic(commands, si);

builtin/reflog.c

@@ -615,7 +615,7 @@ static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 	return status;
 }
 
-static int count_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
+static int count_reflog_ent(struct object_id *ooid, struct object_id *noid,
 		const char *email, unsigned long timestamp, int tz,
 		const char *message, void *cb_data)
 {

builtin/replace.c

@@ -88,78 +88,78 @@ static int list_replace_refs(const char *pattern, const char *format)
 }
 
 typedef int (*each_replace_name_fn)(const char *name, const char *ref,
-				    const unsigned char *sha1);
+				    const struct object_id *oid);
 
 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
 {
 	const char **p, *full_hex;
 	char ref[PATH_MAX];
 	int had_error = 0;
-	unsigned char sha1[20];
+	struct object_id oid;
 
 	for (p = argv; *p; p++) {
-		if (get_sha1(*p, sha1)) {
+		if (get_oid(*p, &oid)) {
 			error("Failed to resolve '%s' as a valid ref.", *p);
 			had_error = 1;
 			continue;
 		}
-		full_hex = sha1_to_hex(sha1);
+		full_hex = oid_to_hex(&oid);
 		snprintf(ref, sizeof(ref), "%s%s", git_replace_ref_base, full_hex);
 		/* read_ref() may reuse the buffer */
 		full_hex = ref + strlen(git_replace_ref_base);
-		if (read_ref(ref, sha1)) {
+		if (read_ref(ref, oid.hash)) {
 			error("replace ref '%s' not found.", full_hex);
 			had_error = 1;
 			continue;
 		}
-		if (fn(full_hex, ref, sha1))
+		if (fn(full_hex, ref, &oid))
 			had_error = 1;
 	}
 	return had_error;
 }
 
 static int delete_replace_ref(const char *name, const char *ref,
-			      const unsigned char *sha1)
+			      const struct object_id *oid)
 {
-	if (delete_ref(NULL, ref, sha1, 0))
+	if (delete_ref(NULL, ref, oid->hash, 0))
 		return 1;
 	printf("Deleted replace ref '%s'\n", name);
 	return 0;
 }
 
-static void check_ref_valid(unsigned char object[20],
-			    unsigned char prev[20],
+static void check_ref_valid(struct object_id *object,
+			    struct object_id *prev,
 			    char *ref,
 			    int ref_size,
 			    int force)
 {
 	if (snprintf(ref, ref_size,
 		     "%s%s", git_replace_ref_base,
-		     sha1_to_hex(object)) > ref_size - 1)
+		     oid_to_hex(object)) > ref_size - 1)
 		die("replace ref name too long: %.*s...", 50, ref);
 	if (check_refname_format(ref, 0))
 		die("'%s' is not a valid ref name.", ref);
 
-	if (read_ref(ref, prev))
-		hashclr(prev);
+	if (read_ref(ref, prev->hash))
+		oidclr(prev);
 	else if (!force)
 		die("replace ref '%s' already exists", ref);
 }
 
-static int replace_object_sha1(const char *object_ref,
-			       unsigned char object[20],
+static int replace_object_oid(const char *object_ref,
+			       struct object_id *object,
 			       const char *replace_ref,
-			       unsigned char repl[20],
+			       struct object_id *repl,
 			       int force)
 {
-	unsigned char prev[20];
+	struct object_id prev;
 	enum object_type obj_type, repl_type;
 	char ref[PATH_MAX];
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 
-	obj_type = sha1_object_info(object, NULL);
-	repl_type = sha1_object_info(repl, NULL);
+	obj_type = sha1_object_info(object->hash, NULL);
+	repl_type = sha1_object_info(repl->hash, NULL);
 	if (!force && obj_type != repl_type)
 		die("Objects must be of the same type.\n"
 		    "'%s' points to a replaced object of type '%s'\n"
@@ -167,11 +167,11 @@ static int replace_object_sha1(const char *object_ref,
 		    object_ref, typename(obj_type),
 		    replace_ref, typename(repl_type));
 
-	check_ref_valid(object, prev, ref, sizeof(ref), force);
+	check_ref_valid(object, &prev, ref, sizeof(ref), force);
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
-	    ref_transaction_update(transaction, ref, repl, prev,
+	    ref_transaction_update(transaction, ref, repl->hash, prev.hash,
 				   0, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
@@ -182,14 +182,14 @@ static int replace_object_sha1(const char *object_ref,
 
 static int replace_object(const char *object_ref, const char *replace_ref, int force)
 {
-	unsigned char object[20], repl[20];
+	struct object_id object, repl;
 
-	if (get_sha1(object_ref, object))
+	if (get_oid(object_ref, &object))
 		die("Failed to resolve '%s' as a valid ref.", object_ref);
-	if (get_sha1(replace_ref, repl))
+	if (get_oid(replace_ref, &repl))
 		die("Failed to resolve '%s' as a valid ref.", replace_ref);
 
-	return replace_object_sha1(object_ref, object, replace_ref, repl, force);
+	return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
 }
 
 /*
@@ -197,7 +197,7 @@ static int replace_object(const char *object_ref, const char *replace_ref, int f
  * If "raw" is true, then the object's raw contents are printed according to
  * "type". Otherwise, we pretty-print the contents for human editing.
  */
-static void export_object(const unsigned char *sha1, enum object_type type,
+static void export_object(const struct object_id *oid, enum object_type type,
 			  int raw, const char *filename)
 {
 	struct child_process cmd = CHILD_PROCESS_INIT;
@@ -213,7 +213,7 @@ static void export_object(const unsigned char *sha1, enum object_type type,
 		argv_array_push(&cmd.args, typename(type));
 	else
 		argv_array_push(&cmd.args, "-p");
-	argv_array_push(&cmd.args, sha1_to_hex(sha1));
+	argv_array_push(&cmd.args, oid_to_hex(oid));
 	cmd.git_cmd = 1;
 	cmd.out = fd;
 
@@ -226,7 +226,7 @@ static void export_object(const unsigned char *sha1, enum object_type type,
  * interpreting it as "type", and writing the result to the object database.
  * The sha1 of the written object is returned via sha1.
  */
-static void import_object(unsigned char *sha1, enum object_type type,
+static void import_object(struct object_id *oid, enum object_type type,
 			  int raw, const char *filename)
 {
 	int fd;
@@ -254,7 +254,7 @@ static void import_object(unsigned char *sha1, enum object_type type,
 
 		if (finish_command(&cmd))
 			die("mktree reported failure");
-		if (get_sha1_hex(result.buf, sha1) < 0)
+		if (get_oid_hex(result.buf, oid) < 0)
 			die("mktree did not return an object name");
 
 		strbuf_release(&result);
@@ -264,7 +264,7 @@ static void import_object(unsigned char *sha1, enum object_type type,
 
 		if (fstat(fd, &st) < 0)
 			die_errno("unable to fstat %s", filename);
-		if (index_fd(sha1, fd, &st, type, NULL, flags) < 0)
+		if (index_fd(oid->hash, fd, &st, type, NULL, flags) < 0)
 			die("unable to write object to database");
 		/* index_fd close()s fd for us */
 	}
@@ -279,29 +279,29 @@ static int edit_and_replace(const char *object_ref, int force, int raw)
 {
 	char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
 	enum object_type type;
-	unsigned char old[20], new[20], prev[20];
+	struct object_id old, new, prev;
 	char ref[PATH_MAX];
 
-	if (get_sha1(object_ref, old) < 0)
+	if (get_oid(object_ref, &old) < 0)
 		die("Not a valid object name: '%s'", object_ref);
 
-	type = sha1_object_info(old, NULL);
+	type = sha1_object_info(old.hash, NULL);
 	if (type < 0)
-		die("unable to get object type for %s", sha1_to_hex(old));
+		die("unable to get object type for %s", oid_to_hex(&old));
 
-	check_ref_valid(old, prev, ref, sizeof(ref), force);
+	check_ref_valid(&old, &prev, ref, sizeof(ref), force);
 
-	export_object(old, type, raw, tmpfile);
+	export_object(&old, type, raw, tmpfile);
 	if (launch_editor(tmpfile, NULL, NULL) < 0)
 		die("editing object file failed");
-	import_object(new, type, raw, tmpfile);
+	import_object(&new, type, raw, tmpfile);
 
 	free(tmpfile);
 
-	if (!hashcmp(old, new))
-		return error("new object is the same as the old one: '%s'", sha1_to_hex(old));
+	if (!oidcmp(&old, &new))
+		return error("new object is the same as the old one: '%s'", oid_to_hex(&old));
 
-	return replace_object_sha1(object_ref, old, "replacement", new, force);
+	return replace_object_oid(object_ref, &old, "replacement", &new, force);
 }
 
 static void replace_parents(struct strbuf *buf, int argc, const char **argv)
@@ -312,7 +312,7 @@ static void replace_parents(struct strbuf *buf, int argc, const char **argv)
 
 	/* find existing parents */
 	parent_start = buf->buf;
-	parent_start += 46; /* "tree " + "hex sha1" + "\n" */
+	parent_start += GIT_SHA1_HEXSZ + 6; /* "tree " + "hex sha1" + "\n" */
 	parent_end = parent_start;
 
 	while (starts_with(parent_end, "parent "))
@@ -320,11 +320,11 @@ static void replace_parents(struct strbuf *buf, int argc, const char **argv)
 
 	/* prepare new parents */
 	for (i = 0; i < argc; i++) {
-		unsigned char sha1[20];
-		if (get_sha1(argv[i], sha1) < 0)
+		struct object_id oid;
+		if (get_oid(argv[i], &oid) < 0)
 			die(_("Not a valid object name: '%s'"), argv[i]);
-		lookup_commit_or_die(sha1, argv[i]);
-		strbuf_addf(&new_parents, "parent %s\n", sha1_to_hex(sha1));
+		lookup_commit_or_die(oid.hash, argv[i]);
+		strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&oid));
 	}
 
 	/* replace existing parents with new ones */
@@ -345,12 +345,12 @@ static void check_one_mergetag(struct commit *commit,
 {
 	struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
 	const char *ref = mergetag_data->argv[0];
-	unsigned char tag_sha1[20];
+	struct object_id tag_oid;
 	struct tag *tag;
 	int i;
 
-	hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), tag_sha1);
-	tag = lookup_tag(tag_sha1);
+	hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), tag_oid.hash);
+	tag = lookup_tag(tag_oid.hash);
 	if (!tag)
 		die(_("bad mergetag in commit '%s'"), ref);
 	if (parse_tag_buffer(tag, extra->value, extra->len))
@@ -366,7 +366,7 @@ static void check_one_mergetag(struct commit *commit,
 	}
 
 	die(_("original commit '%s' contains mergetag '%s' that is discarded; "
-	      "use --edit instead of --graft"), ref, sha1_to_hex(tag_sha1));
+	      "use --edit instead of --graft"), ref, oid_to_hex(&tag_oid));
 }
 
 static void check_mergetags(struct commit *commit, int argc, const char **argv)
@@ -380,16 +380,16 @@ static void check_mergetags(struct commit *commit, int argc, const char **argv)
 
 static int create_graft(int argc, const char **argv, int force)
 {
-	unsigned char old[20], new[20];
+	struct object_id old, new;
 	const char *old_ref = argv[0];
 	struct commit *commit;
 	struct strbuf buf = STRBUF_INIT;
 	const char *buffer;
 	unsigned long size;
 
-	if (get_sha1(old_ref, old) < 0)
+	if (get_oid(old_ref, &old) < 0)
 		die(_("Not a valid object name: '%s'"), old_ref);
-	commit = lookup_commit_or_die(old, old_ref);
+	commit = lookup_commit_or_die(old.hash, old_ref);
 
 	buffer = get_commit_buffer(commit, &size);
 	strbuf_add(&buf, buffer, size);
@@ -404,15 +404,15 @@ static int create_graft(int argc, const char **argv, int force)
 
 	check_mergetags(commit, argc, argv);
 
-	if (write_sha1_file(buf.buf, buf.len, commit_type, new))
+	if (write_sha1_file(buf.buf, buf.len, commit_type, new.hash))
 		die(_("could not write replacement commit for: '%s'"), old_ref);
 
 	strbuf_release(&buf);
 
-	if (!hashcmp(old, new))
-		return error("new commit is the same as the old one: '%s'", sha1_to_hex(old));
+	if (!oidcmp(&old, &new))
+		return error("new commit is the same as the old one: '%s'", oid_to_hex(&old));
 
-	return replace_object_sha1(old_ref, old, "replacement", new, force);
+	return replace_object_oid(old_ref, &old, "replacement", &new, force);
 }
 
 int cmd_replace(int argc, const char **argv, const char *prefix)

cache.h

@@ -1363,6 +1363,15 @@ extern char *oid_to_hex_r(char *out, const struct object_id *oid);
 extern char *sha1_to_hex(const unsigned char *sha1);	/* static buffer result! */
 extern char *oid_to_hex(const struct object_id *oid);	/* same static buffer as sha1_to_hex */
 
+/*
+ * Parse a 40-character hexadecimal object ID starting from hex, updating the
+ * pointer specified by end when parsing stops.  The resulting object ID is
+ * stored in oid.  Returns 0 on success.  Parsing will stop on the first NUL or
+ * other invalid character.  end is only updated on success; otherwise, it is
+ * unmodified.
+ */
+extern int parse_oid_hex(const char *hex, struct object_id *oid, const char **end);
+
 /*
  * This reads short-hand syntax that not only evaluates to a commit
  * object name, but also can act as if the end user spelled the name
@@ -1673,6 +1682,12 @@ extern void check_pack_index_ptr(const struct packed_git *p, const void *ptr);
  * error.
  */
 extern const unsigned char *nth_packed_object_sha1(struct packed_git *, uint32_t n);
+/*
+ * Like nth_packed_object_sha1, but write the data into the object specified by
+ * the the first argument.  Returns the first argument on success, and NULL on
+ * error.
+ */
+extern const struct object_id *nth_packed_object_oid(struct object_id *, struct packed_git *, uint32_t n);
 
 /*
  * Return the offset of the nth object within the specified packfile.
@@ -1714,7 +1729,7 @@ extern int unpack_object_header(struct packed_git *, struct pack_window **, off_
  * scratch buffer, but restored to its original contents before
  * the function returns.
  */
-typedef int each_loose_object_fn(const unsigned char *sha1,
+typedef int each_loose_object_fn(const struct object_id *oid,
 				 const char *path,
 				 void *data);
 typedef int each_loose_cruft_fn(const char *basename,
@@ -1740,7 +1755,7 @@ int for_each_loose_file_in_objdir_buf(struct strbuf *path,
  * LOCAL_ONLY flag is set).
  */
 #define FOR_EACH_OBJECT_LOCAL_ONLY 0x1
-typedef int each_packed_object_fn(const unsigned char *sha1,
+typedef int each_packed_object_fn(const struct object_id *oid,
 				  struct packed_git *pack,
 				  uint32_t pos,
 				  void *data);

hex.c

@@ -53,6 +53,14 @@ int get_oid_hex(const char *hex, struct object_id *oid)
 	return get_sha1_hex(hex, oid->hash);
 }
 
+int parse_oid_hex(const char *hex, struct object_id *oid, const char **end)
+{
+	int ret = get_oid_hex(hex, oid);
+	if (!ret)
+		*end = hex + GIT_SHA1_HEXSZ;
+	return ret;
+}
+
 char *sha1_to_hex_r(char *buffer, const unsigned char *sha1)
 {
 	static const char hex[] = "0123456789abcdef";

reachable.c

@@ -58,7 +58,7 @@ struct recent_data {
 	unsigned long timestamp;
 };
 
-static void add_recent_object(const unsigned char *sha1,
+static void add_recent_object(const struct object_id *oid,
 			      unsigned long mtime,
 			      struct recent_data *data)
 {
@@ -75,37 +75,37 @@ static void add_recent_object(const unsigned char *sha1,
 	 * later processing, and the revision machinery expects
 	 * commits and tags to have been parsed.
 	 */
-	type = sha1_object_info(sha1, NULL);
+	type = sha1_object_info(oid->hash, NULL);
 	if (type < 0)
-		die("unable to get object info for %s", sha1_to_hex(sha1));
+		die("unable to get object info for %s", oid_to_hex(oid));
 
 	switch (type) {
 	case OBJ_TAG:
 	case OBJ_COMMIT:
-		obj = parse_object_or_die(sha1, NULL);
+		obj = parse_object_or_die(oid->hash, NULL);
 		break;
 	case OBJ_TREE:
-		obj = (struct object *)lookup_tree(sha1);
+		obj = (struct object *)lookup_tree(oid->hash);
 		break;
 	case OBJ_BLOB:
-		obj = (struct object *)lookup_blob(sha1);
+		obj = (struct object *)lookup_blob(oid->hash);
 		break;
 	default:
 		die("unknown object type for %s: %s",
-		    sha1_to_hex(sha1), typename(type));
+		    oid_to_hex(oid), typename(type));
 	}
 
 	if (!obj)
-		die("unable to lookup %s", sha1_to_hex(sha1));
+		die("unable to lookup %s", oid_to_hex(oid));
 
 	add_pending_object(data->revs, obj, "");
 }
 
-static int add_recent_loose(const unsigned char *sha1,
+static int add_recent_loose(const struct object_id *oid,
 			    const char *path, void *data)
 {
 	struct stat st;
-	struct object *obj = lookup_object(sha1);
+	struct object *obj = lookup_object(oid->hash);
 
 	if (obj && obj->flags & SEEN)
 		return 0;
@@ -119,22 +119,22 @@ static int add_recent_loose(const unsigned char *sha1,
 		 */
 		if (errno == ENOENT)
 			return 0;
-		return error_errno("unable to stat %s", sha1_to_hex(sha1));
+		return error_errno("unable to stat %s", oid_to_hex(oid));
 	}
 
-	add_recent_object(sha1, st.st_mtime, data);
+	add_recent_object(oid, st.st_mtime, data);
 	return 0;
 }
 
-static int add_recent_packed(const unsigned char *sha1,
+static int add_recent_packed(const struct object_id *oid,
 			     struct packed_git *p, uint32_t pos,
 			     void *data)
 {
-	struct object *obj = lookup_object(sha1);
+	struct object *obj = lookup_object(oid->hash);
 
 	if (obj && obj->flags & SEEN)
 		return 0;
-	add_recent_object(sha1, p->mtime, data);
+	add_recent_object(oid, p->mtime, data);
 	return 0;
 }
 

ref-filter.c

@@ -1297,9 +1297,9 @@ static void populate_value(struct ref_array_item *ref)
 	ref->value = xcalloc(used_atom_cnt, sizeof(struct atom_value));
 
 	if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
-		unsigned char unused1[20];
+		struct object_id unused1;
 		ref->symref = resolve_refdup(ref->refname, RESOLVE_REF_READING,
-					     unused1, NULL);
+					     unused1.hash, NULL);
 		if (!ref->symref)
 			ref->symref = "";
 	}

reflog-walk.c

@@ -10,7 +10,7 @@ struct complete_reflogs {
 	char *ref;
 	const char *short_ref;
 	struct reflog_info {
-		unsigned char osha1[20], nsha1[20];
+		struct object_id ooid, noid;
 		char *email;
 		unsigned long timestamp;
 		int tz;
@@ -19,7 +19,7 @@ struct complete_reflogs {
 	int nr, alloc;
 };
 
-static int read_one_reflog(unsigned char *osha1, unsigned char *nsha1,
+static int read_one_reflog(struct object_id *ooid, struct object_id *noid,
 		const char *email, unsigned long timestamp, int tz,
 		const char *message, void *cb_data)
 {
@@ -28,8 +28,8 @@ static int read_one_reflog(unsigned char *osha1, unsigned char *nsha1,
 
 	ALLOC_GROW(array->items, array->nr + 1, array->alloc);
 	item = array->items + array->nr;
-	hashcpy(item->osha1, osha1);
-	hashcpy(item->nsha1, nsha1);
+	oidcpy(&item->ooid, ooid);
+	oidcpy(&item->noid, noid);
 	item->email = xstrdup(email);
 	item->timestamp = timestamp;
 	item->tz = tz;
@@ -45,11 +45,11 @@ static struct complete_reflogs *read_complete_reflog(const char *ref)
 	reflogs->ref = xstrdup(ref);
 	for_each_reflog_ent(ref, read_one_reflog, reflogs);
 	if (reflogs->nr == 0) {
-		unsigned char sha1[20];
+		struct object_id oid;
 		const char *name;
 		void *name_to_free;
 		name = name_to_free = resolve_refdup(ref, RESOLVE_REF_READING,
-						     sha1, NULL);
+						     oid.hash, NULL);
 		if (name) {
 			for_each_reflog_ent(name, read_one_reflog, reflogs);
 			free(name_to_free);
@@ -172,18 +172,18 @@ int add_reflog_for_walk(struct reflog_walk_info *info,
 		reflogs = item->util;
 	else {
 		if (*branch == '\0') {
-			unsigned char sha1[20];
+			struct object_id oid;
 			free(branch);
-			branch = resolve_refdup("HEAD", 0, sha1, NULL);
+			branch = resolve_refdup("HEAD", 0, oid.hash, NULL);
 			if (!branch)
 				die ("No current branch");
 
 		}
 		reflogs = read_complete_reflog(branch);
 		if (!reflogs || reflogs->nr == 0) {
-			unsigned char sha1[20];
+			struct object_id oid;
 			char *b;
-			if (dwim_log(branch, strlen(branch), sha1, &b) == 1) {
+			if (dwim_log(branch, strlen(branch), oid.hash, &b) == 1) {
 				if (reflogs) {
 					free(reflogs->ref);
 					free(reflogs);
@@ -238,13 +238,13 @@ void fake_reflog_parent(struct reflog_walk_info *info, struct commit *commit)
 	do {
 		reflog = &commit_reflog->reflogs->items[commit_reflog->recno];
 		commit_reflog->recno--;
-		logobj = parse_object(reflog->osha1);
+		logobj = parse_object(reflog->ooid.hash);
 	} while (commit_reflog->recno && (logobj && logobj->type != OBJ_COMMIT));
 
-	if (!logobj && commit_reflog->recno >= 0 && is_null_sha1(reflog->osha1)) {
+	if (!logobj && commit_reflog->recno >= 0 && is_null_sha1(reflog->ooid.hash)) {
 		/* a root commit, but there are still more entries to show */
 		reflog = &commit_reflog->reflogs->items[commit_reflog->recno];
-		logobj = parse_object(reflog->nsha1);
+		logobj = parse_object(reflog->noid.hash);
 	}
 
 	if (!logobj || logobj->type != OBJ_COMMIT) {

refs.c

@@ -675,7 +675,7 @@ struct read_ref_at_cb {
 	int *cutoff_cnt;
 };
 
-static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
+static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 		const char *email, unsigned long timestamp, int tz,
 		const char *message, void *cb_data)
 {
@@ -699,30 +699,30 @@ static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
 		 * hold the values for the previous record.
 		 */
 		if (!is_null_sha1(cb->osha1)) {
-			hashcpy(cb->sha1, nsha1);
-			if (hashcmp(cb->osha1, nsha1))
+			hashcpy(cb->sha1, noid->hash);
+			if (hashcmp(cb->osha1, noid->hash))
 				warning("Log for ref %s has gap after %s.",
 					cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
 		}
 		else if (cb->date == cb->at_time)
-			hashcpy(cb->sha1, nsha1);
-		else if (hashcmp(nsha1, cb->sha1))
+			hashcpy(cb->sha1, noid->hash);
+		else if (hashcmp(noid->hash, cb->sha1))
 			warning("Log for ref %s unexpectedly ended on %s.",
 				cb->refname, show_date(cb->date, cb->tz,
 						       DATE_MODE(RFC2822)));
-		hashcpy(cb->osha1, osha1);
-		hashcpy(cb->nsha1, nsha1);
+		hashcpy(cb->osha1, ooid->hash);
+		hashcpy(cb->nsha1, noid->hash);
 		cb->found_it = 1;
 		return 1;
 	}
-	hashcpy(cb->osha1, osha1);
-	hashcpy(cb->nsha1, nsha1);
+	hashcpy(cb->osha1, ooid->hash);
+	hashcpy(cb->nsha1, noid->hash);
 	if (cb->cnt > 0)
 		cb->cnt--;
 	return 0;
 }
 
-static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
+static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
 				  const char *email, unsigned long timestamp,
 				  int tz, const char *message, void *cb_data)
 {
@@ -736,9 +736,9 @@ static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
 		*cb->cutoff_tz = tz;
 	if (cb->cutoff_cnt)
 		*cb->cutoff_cnt = cb->reccnt;
-	hashcpy(cb->sha1, osha1);
+	hashcpy(cb->sha1, ooid->hash);
 	if (is_null_sha1(cb->sha1))
-		hashcpy(cb->sha1, nsha1);
+		hashcpy(cb->sha1, noid->hash);
 	/* We just want the first entry */
 	return 1;
 }

refs.h

@@ -292,7 +292,7 @@ int delete_reflog(const char *refname);
 
 /* iterate over reflog entries */
 typedef int each_reflog_ent_fn(
-		unsigned char *old_sha1, unsigned char *new_sha1,
+		struct object_id *old_oid, struct object_id *new_oid,
 		const char *committer, unsigned long timestamp,
 		int tz, const char *msg, void *cb_data);
 

refs/files-backend.c

@@ -3102,16 +3102,17 @@ static int files_delete_reflog(struct ref_store *ref_store,
 
 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
 {
-	unsigned char osha1[20], nsha1[20];
+	struct object_id ooid, noid;
 	char *email_end, *message;
 	unsigned long timestamp;
 	int tz;
+	const char *p = sb->buf;
 
 	/* old SP new SP name <email> SP time TAB msg LF */
-	if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
-	    get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
-	    get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
-	    !(email_end = strchr(sb->buf + 82, '>')) ||
+	if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
+	    parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
+	    parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
+	    !(email_end = strchr(p, '>')) ||
 	    email_end[1] != ' ' ||
 	    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
 	    !message || message[0] != ' ' ||
@@ -3125,7 +3126,7 @@ static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *c
 		message += 6;
 	else
 		message += 7;
-	return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
+	return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
 }
 
 static char *find_beginning_of_line(char *bob, char *scan)
@@ -3954,10 +3955,10 @@ struct expire_reflog_cb {
 	reflog_expiry_should_prune_fn *should_prune_fn;
 	void *policy_cb;
 	FILE *newlog;
-	unsigned char last_kept_sha1[20];
+	struct object_id last_kept_oid;
 };
 
-static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
+static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
 			     const char *email, unsigned long timestamp, int tz,
 			     const char *message, void *cb_data)
 {
@@ -3965,9 +3966,9 @@ static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 	struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
 
 	if (cb->flags & EXPIRE_REFLOGS_REWRITE)
-		osha1 = cb->last_kept_sha1;
+		ooid = &cb->last_kept_oid;
 
-	if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,
+	if ((*cb->should_prune_fn)(ooid->hash, noid->hash, email, timestamp, tz,
 				   message, policy_cb)) {
 		if (!cb->newlog)
 			printf("would prune %s", message);
@@ -3976,9 +3977,9 @@ static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 	} else {
 		if (cb->newlog) {
 			fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
-				sha1_to_hex(osha1), sha1_to_hex(nsha1),
+				oid_to_hex(ooid), oid_to_hex(noid),
 				email, timestamp, tz, message);
-			hashcpy(cb->last_kept_sha1, nsha1);
+			oidcpy(&cb->last_kept_oid, noid);
 		}
 		if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
 			printf("keep %s", message);
@@ -4065,14 +4066,14 @@ static int files_reflog_expire(struct ref_store *ref_store,
 		 */
 		int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
 			!(type & REF_ISSYMREF) &&
-			!is_null_sha1(cb.last_kept_sha1);
+			!is_null_oid(&cb.last_kept_oid);
 
 		if (close_lock_file(&reflog_lock)) {
 			status |= error("couldn't write %s: %s", log_file,
 					strerror(errno));
 		} else if (update &&
 			   (write_in_full(get_lock_file_fd(lock->lk),
-				sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
+				oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
 			    write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
 			    close_ref(lock) < 0)) {
 			status |= error("couldn't write %s",

revision.c

@@ -1196,11 +1196,11 @@ static void handle_refs(const char *submodule, struct rev_info *revs, unsigned f
 	for_each(submodule, handle_one_ref, &cb);
 }
 
-static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
+static void handle_one_reflog_commit(struct object_id *oid, void *cb_data)
 {
 	struct all_refs_cb *cb = cb_data;
-	if (!is_null_sha1(sha1)) {
-		struct object *o = parse_object(sha1);
+	if (!is_null_oid(oid)) {
+		struct object *o = parse_object(oid->hash);
 		if (o) {
 			o->flags |= cb->all_flags;
 			/* ??? CMDLINEFLAGS ??? */
@@ -1214,12 +1214,12 @@ static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 	}
 }
 
-static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
+static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 		const char *email, unsigned long timestamp, int tz,
 		const char *message, void *cb_data)
 {
-	handle_one_reflog_commit(osha1, cb_data);
-	handle_one_reflog_commit(nsha1, cb_data);
+	handle_one_reflog_commit(ooid, cb_data);
+	handle_one_reflog_commit(noid, cb_data);
 	return 0;
 }
 

sha1_file.c

@@ -2706,6 +2706,17 @@ const unsigned char *nth_packed_object_sha1(struct packed_git *p,
 	}
 }
 
+const struct object_id *nth_packed_object_oid(struct object_id *oid,
+					      struct packed_git *p,
+					      uint32_t n)
+{
+	const unsigned char *hash = nth_packed_object_sha1(p, n);
+	if (!hash)
+		return NULL;
+	hashcpy(oid->hash, hash);
+	return oid;
+}
+
 void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
 {
 	const unsigned char *ptr = vptr;
@@ -3752,15 +3763,15 @@ static int for_each_file_in_obj_subdir(int subdir_nr,
 		strbuf_setlen(path, baselen);
 		strbuf_addf(path, "/%s", de->d_name);
 
-		if (strlen(de->d_name) == 38)  {
-			char hex[41];
-			unsigned char sha1[20];
+		if (strlen(de->d_name) == GIT_SHA1_HEXSZ - 2)  {
+			char hex[GIT_SHA1_HEXSZ+1];
+			struct object_id oid;
 
 			snprintf(hex, sizeof(hex), "%02x%s",
 				 subdir_nr, de->d_name);
-			if (!get_sha1_hex(hex, sha1)) {
+			if (!get_oid_hex(hex, &oid)) {
 				if (obj_cb) {
-					r = obj_cb(sha1, path->buf, data);
+					r = obj_cb(&oid, path->buf, data);
 					if (r)
 						break;
 				}
@@ -3866,13 +3877,13 @@ static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn c
 	int r = 0;
 
 	for (i = 0; i < p->num_objects; i++) {
-		const unsigned char *sha1 = nth_packed_object_sha1(p, i);
+		struct object_id oid;
 
-		if (!sha1)
+		if (!nth_packed_object_oid(&oid, p, i))
 			return error("unable to get sha1 of object %u in %s",
 				     i, p->pack_name);
 
-		r = cb(sha1, p, i, data);
+		r = cb(&oid, p, i, data);
 		if (r)
 			break;
 	}

sha1_name.c

@@ -1051,7 +1051,7 @@ struct grab_nth_branch_switch_cbdata {
 	struct strbuf buf;
 };
 
-static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
+static int grab_nth_branch_switch(struct object_id *ooid, struct object_id *noid,
 				  const char *email, unsigned long timestamp, int tz,
 				  const char *message, void *cb_data)
 {

transport.c

@@ -471,11 +471,11 @@ void transport_print_push_status(const char *dest, struct ref *refs,
 {
 	struct ref *ref;
 	int n = 0;
-	unsigned char head_sha1[20];
+	struct object_id head_oid;
 	char *head;
 	int summary_width = transport_summary_width(refs);
 
-	head = resolve_refdup("HEAD", RESOLVE_REF_READING, head_sha1, NULL);
+	head = resolve_refdup("HEAD", RESOLVE_REF_READING, head_oid.hash, NULL);
 
 	if (verbose) {
 		for (ref = refs; ref; ref = ref->next)

wt-status.c

@@ -121,7 +121,7 @@ static void status_printf_more(struct wt_status *s, const char *color,
 
 void wt_status_prepare(struct wt_status *s)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 
 	memset(s, 0, sizeof(*s));
 	memcpy(s->color_palette, default_wt_status_colors,
@@ -129,7 +129,7 @@ void wt_status_prepare(struct wt_status *s)
 	s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
 	s->use_color = -1;
 	s->relative_paths = 1;
-	s->branch = resolve_refdup("HEAD", 0, sha1, NULL);
+	s->branch = resolve_refdup("HEAD", 0, oid.hash, NULL);
 	s->reference = "HEAD";
 	s->fp = stdout;
 	s->index_file = get_index_file();
@@ -1115,16 +1115,16 @@ static void abbrev_sha1_in_line(struct strbuf *line)
 
 	split = strbuf_split_max(line, ' ', 3);
 	if (split[0] && split[1]) {
-		unsigned char sha1[20];
+		struct object_id oid;
 
 		/*
 		 * strbuf_split_max left a space. Trim it and re-add
 		 * it after abbreviation.
 		 */
 		strbuf_trim(split[1]);
-		if (!get_sha1(split[1]->buf, sha1)) {
+		if (!get_oid(split[1]->buf, &oid)) {
 			strbuf_reset(split[1]);
-			strbuf_add_unique_abbrev(split[1], sha1,
+			strbuf_add_unique_abbrev(split[1], oid.hash,
 						 DEFAULT_ABBREV);
 			strbuf_addch(split[1], ' ');
 			strbuf_reset(line);
@@ -1340,7 +1340,7 @@ static void show_bisect_in_progress(struct wt_status *s,
 static char *get_branch(const struct worktree *wt, const char *path)
 {
 	struct strbuf sb = STRBUF_INIT;
-	unsigned char sha1[20];
+	struct object_id oid;
 	const char *branch_name;
 
 	if (strbuf_read_file(&sb, worktree_git_path(wt, "%s", path), 0) <= 0)
@@ -1354,9 +1354,9 @@ static char *get_branch(const struct worktree *wt, const char *path)
 		strbuf_remove(&sb, 0, branch_name - sb.buf);
 	else if (starts_with(sb.buf, "refs/"))
 		;
-	else if (!get_sha1_hex(sb.buf, sha1)) {
+	else if (!get_oid_hex(sb.buf, &oid)) {
 		strbuf_reset(&sb);
-		strbuf_add_unique_abbrev(&sb, sha1, DEFAULT_ABBREV);
+		strbuf_add_unique_abbrev(&sb, oid.hash, DEFAULT_ABBREV);
 	} else if (!strcmp(sb.buf, "detached HEAD")) /* rebase */
 		goto got_nothing;
 	else			/* bisect */
@@ -1370,10 +1370,10 @@ got_nothing:
 
 struct grab_1st_switch_cbdata {
 	struct strbuf buf;
-	unsigned char nsha1[20];
+	struct object_id noid;
 };
 
-static int grab_1st_switch(unsigned char *osha1, unsigned char *nsha1,
+static int grab_1st_switch(struct object_id *ooid, struct object_id *noid,
 			   const char *email, unsigned long timestamp, int tz,
 			   const char *message, void *cb_data)
 {
@@ -1387,13 +1387,13 @@ static int grab_1st_switch(unsigned char *osha1, unsigned char *nsha1,
 		return 0;
 	target += strlen(" to ");
 	strbuf_reset(&cb->buf);
-	hashcpy(cb->nsha1, nsha1);
+	oidcpy(&cb->noid, noid);
 	end = strchrnul(target, '\n');
 	strbuf_add(&cb->buf, target, end - target);
 	if (!strcmp(cb->buf.buf, "HEAD")) {
 		/* HEAD is relative. Resolve it to the right reflog entry. */
 		strbuf_reset(&cb->buf);
-		strbuf_add_unique_abbrev(&cb->buf, nsha1, DEFAULT_ABBREV);
+		strbuf_add_unique_abbrev(&cb->buf, noid->hash, DEFAULT_ABBREV);
 	}
 	return 1;
 }
@@ -1402,7 +1402,7 @@ static void wt_status_get_detached_from(struct wt_status_state *state)
 {
 	struct grab_1st_switch_cbdata cb;
 	struct commit *commit;
-	unsigned char sha1[20];
+	struct object_id oid;
 	char *ref = NULL;
 
 	strbuf_init(&cb.buf, 0);
@@ -1411,22 +1411,22 @@ static void wt_status_get_detached_from(struct wt_status_state *state)
 		return;
 	}
 
-	if (dwim_ref(cb.buf.buf, cb.buf.len, sha1, &ref) == 1 &&
+	if (dwim_ref(cb.buf.buf, cb.buf.len, oid.hash, &ref) == 1 &&
 	    /* sha1 is a commit? match without further lookup */
-	    (!hashcmp(cb.nsha1, sha1) ||
+	    (!oidcmp(&cb.noid, &oid) ||
 	     /* perhaps sha1 is a tag, try to dereference to a commit */
-	     ((commit = lookup_commit_reference_gently(sha1, 1)) != NULL &&
-	      !hashcmp(cb.nsha1, commit->object.oid.hash)))) {
+	     ((commit = lookup_commit_reference_gently(oid.hash, 1)) != NULL &&
+	      !oidcmp(&cb.noid, &commit->object.oid)))) {
 		const char *from = ref;
 		if (!skip_prefix(from, "refs/tags/", &from))
 			skip_prefix(from, "refs/remotes/", &from);
 		state->detached_from = xstrdup(from);
 	} else
 		state->detached_from =
-			xstrdup(find_unique_abbrev(cb.nsha1, DEFAULT_ABBREV));
-	hashcpy(state->detached_sha1, cb.nsha1);
-	state->detached_at = !get_sha1("HEAD", sha1) &&
-			     !hashcmp(sha1, state->detached_sha1);
+			xstrdup(find_unique_abbrev(cb.noid.hash, DEFAULT_ABBREV));
+	hashcpy(state->detached_sha1, cb.noid.hash);
+	state->detached_at = !get_oid("HEAD", &oid) &&
+			     !hashcmp(oid.hash, state->detached_sha1);
 
 	free(ref);
 	strbuf_release(&cb.buf);
@@ -1476,22 +1476,22 @@ void wt_status_get_state(struct wt_status_state *state,
 			 int get_detached_from)
 {
 	struct stat st;
-	unsigned char sha1[20];
+	struct object_id oid;
 
 	if (!stat(git_path_merge_head(), &st)) {
 		state->merge_in_progress = 1;
 	} else if (wt_status_check_rebase(NULL, state)) {
 		;		/* all set */
 	} else if (!stat(git_path_cherry_pick_head(), &st) &&
-			!get_sha1("CHERRY_PICK_HEAD", sha1)) {
+			!get_oid("CHERRY_PICK_HEAD", &oid)) {
 		state->cherry_pick_in_progress = 1;
-		hashcpy(state->cherry_pick_head_sha1, sha1);
+		hashcpy(state->cherry_pick_head_sha1, oid.hash);
 	}
 	wt_status_check_bisect(NULL, state);
 	if (!stat(git_path_revert_head(), &st) &&
-	    !get_sha1("REVERT_HEAD", sha1)) {
+	    !get_oid("REVERT_HEAD", &oid)) {
 		state->revert_in_progress = 1;
-		hashcpy(state->revert_head_sha1, sha1);
+		hashcpy(state->revert_head_sha1, oid.hash);
 	}
 
 	if (get_detached_from)