C++ deref_tag函数代码示例

static int grep_objects(struct grep_opt *opt, const struct pathspec *pathspec,
			const struct object_array *list)
{
	unsigned int i;
	int hit = 0;
	const unsigned int nr = list->nr;

	for (i = 0; i < nr; i++) {
		struct object *real_obj;
		real_obj = deref_tag(list->objects[i].item, NULL, 0);
		if (grep_object(opt, pathspec, real_obj, list->objects[i].name)) {
			hit = 1;
			if (opt->status_only)
				break;
		}
	}
	return hit;
}

static struct commit *get_ref(const char *ref)
{
	unsigned char sha1[20];
	struct object *object;

	if (get_sha1(ref, sha1))
		die("Could not resolve ref '%s'", ref);
	object = deref_tag(parse_object(sha1), ref, strlen(ref));
	if (!object)
		return NULL;
	if (object->type == OBJ_TREE)
		return make_virtual_commit((struct tree*)object,
			better_branch_name(ref));
	if (object->type != OBJ_COMMIT)
		return NULL;
	if (parse_commit((struct commit *)object))
		die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
	return (struct commit *)object;
}

int git_deref_tag(const unsigned char *tagsha1, GIT_HASH refhash)
{
	struct object *obj = NULL;
	obj = parse_object(tagsha1);
	if (!obj)
		return -1;

	if (obj->type == OBJ_TAG)
	{
			obj = deref_tag(obj, "", 0);
			if (!obj)
				return -1;

			memcpy(refhash, obj->sha1, sizeof(GIT_HASH));
			return 0;
	}

	return -1;
}

static int add_info_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
{
	FILE *fp = cb_data;
	struct object *o = parse_object(sha1);
	if (!o)
		return -1;

	if (fprintf(fp, "%s	%s\n", sha1_to_hex(sha1), path) < 0)
		return -1;

	if (o->type == OBJ_TAG) {
		o = deref_tag(o, path, 0);
		if (o)
			if (fprintf(fp, "%s	%s^{}\n",
				sha1_to_hex(o->sha1), path) < 0)
				return -1;
	}
	return 0;
}

static int show_text_ref(const char *name, const unsigned char *sha1,
	int flag, void *cb_data)
{
	const char *name_nons = strip_namespace(name);
	struct strbuf *buf = cb_data;
	struct object *o = parse_object(sha1);
	if (!o)
		return 0;

	strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name_nons);
	if (o->type == OBJ_TAG) {
		o = deref_tag(o, name, 0);
		if (!o)
			return 0;
		strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1),
			    name_nons);
	}
	return 0;
}

static int show_text_ref(const char *name, const struct object_id *oid,
			 int flag, void *cb_data)
{
	const char *name_nons = strip_namespace(name);
	struct strbuf *buf = cb_data;
	struct object *o = parse_object(oid->hash);
	if (!o)
		return 0;

	strbuf_addf(buf, "%s\t%s\n", oid_to_hex(oid), name_nons);
	if (o->type == OBJ_TAG) {
		o = deref_tag(o, name, 0);
		if (!o)
			return 0;
		strbuf_addf(buf, "%s\t%s^{}\n", oid_to_hex(&o->oid),
			    name_nons);
	}
	return 0;
}

static int add_info_ref(const char *path, const struct object_id *oid,
			int flag, void *cb_data)
{
	FILE *fp = cb_data;
	struct object *o = parse_object(oid->hash);
	if (!o)
		return -1;

	if (fprintf(fp, "%s	%s\n", oid_to_hex(oid), path) < 0)
		return -1;

	if (o->type == OBJ_TAG) {
		o = deref_tag(o, path, 0);
		if (o)
			if (fprintf(fp, "%s	%s^{}\n",
				oid_to_hex(&o->oid), path) < 0)
				return -1;
	}
	return 0;
}

static void add_remote_info_ref(struct remote_ls_ctx *ls)
{
	struct strbuf *buf = (struct strbuf *)ls->userData;
	struct object *o;
	struct ref *ref;

	ref = alloc_ref(ls->dentry_name);

	if (http_fetch_ref(repo->url, ref) != 0) {
		fprintf(stderr,
			"Unable to fetch ref %s from %s\n",
			ls->dentry_name, repo->url);
		aborted = 1;
		free(ref);
		return;
	}

	o = parse_object(&ref->old_oid);
	if (!o) {
		fprintf(stderr,
			"Unable to parse object %s for remote ref %s\n",
			oid_to_hex(&ref->old_oid), ls->dentry_name);
		aborted = 1;
		free(ref);
		return;
	}

	strbuf_addf(buf, "%s\t%s\n",
		    oid_to_hex(&ref->old_oid), ls->dentry_name);

	if (o->type == OBJ_TAG) {
		o = deref_tag(o, ls->dentry_name, 0);
		if (o)
			strbuf_addf(buf, "%s\t%s^{}\n",
				    oid_to_hex(&o->oid), ls->dentry_name);
	}
	free(ref);
}

static int handle_one_ref(const char *path, const unsigned char *sha1,
			  int flags, void *cb_data)
{
	struct pack_refs_cb_data *cb = cb_data;
	int is_tag_ref;

	/* Do not pack the symbolic refs */
	if ((flags & REF_ISSYMREF))
		return 0;
	is_tag_ref = !prefixcmp(path, "refs/tags/");

	/* ALWAYS pack refs that were already packed or are tags */
	if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref && !(flags & REF_ISPACKED))
		return 0;

	fprintf(cb->refs_file, "%s %s\n", sha1_to_hex(sha1), path);
	if (is_tag_ref) {
		struct object *o = parse_object(sha1);
		if (o->type == OBJ_TAG) {
			o = deref_tag(o, path, 0);
			if (o)
				fprintf(cb->refs_file, "^%s\n",
					sha1_to_hex(o->sha1));
		}
	}

	if ((cb->flags & PACK_REFS_PRUNE) && !do_not_prune(flags)) {
		int namelen = strlen(path) + 1;
		struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
		hashcpy(n->sha1, sha1);
		strcpy(n->name, path);
		n->next = cb->ref_to_prune;
		cb->ref_to_prune = n;
	}
	return 0;
}

static struct commit *dwim_reverse_initial(struct rev_info *revs,
					   const char **name_p)
{
	/*
	 * DWIM "git blame --reverse ONE -- PATH" as
	 * "git blame --reverse ONE..HEAD -- PATH" but only do so
	 * when it makes sense.
	 */
	struct object *obj;
	struct commit *head_commit;
	struct object_id head_oid;

	if (revs->pending.nr != 1)
		return NULL;

	/* Is that sole rev a committish? */
	obj = revs->pending.objects[0].item;
	obj = deref_tag(obj, NULL, 0);
	if (obj->type != OBJ_COMMIT)
		return NULL;

	/* Do we have HEAD? */
	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
		return NULL;
	head_commit = lookup_commit_reference_gently(&head_oid, 1);
	if (!head_commit)
		return NULL;

	/* Turn "ONE" into "ONE..HEAD" then */
	obj->flags |= UNINTERESTING;
	add_pending_object(revs, &head_commit->object, "HEAD");

	if (name_p)
		*name_p = revs->pending.objects[0].name;
	return (struct commit *)obj;
}

//.........这里部分代码省略.........
		append_grep_pattern(&opt, argv[0], "command line", 0,
				    GREP_PATTERN);
		argv++;
		argc--;
	}

	if (!opt.pattern_list)
		die("no pattern given.");
	if (!opt.fixed && opt.ignore_case)
		opt.regflags |= REG_ICASE;
	if ((opt.regflags != REG_NEWLINE) && opt.fixed)
		die("cannot mix --fixed-strings and regexp");

#ifndef NO_PTHREADS
	if (online_cpus() == 1 || !grep_threads_ok(&opt))
		use_threads = 0;

	if (use_threads)
		start_threads(&opt);
#else
	use_threads = 0;
#endif

	compile_grep_patterns(&opt);

	/* Check revs and then paths */
	for (i = 0; i < argc; i++) {
		const char *arg = argv[i];
		unsigned char sha1[20];
		/* Is it a rev? */
		if (!get_sha1(arg, sha1)) {
			struct object *object = parse_object(sha1);
			if (!object)
				die("bad object %s", arg);
			add_object_array(object, arg, &list);
			continue;
		}
		if (!strcmp(arg, "--")) {
			i++;
			seen_dashdash = 1;
		}
		break;
	}

	/* The rest are paths */
	if (!seen_dashdash) {
		int j;
		for (j = i; j < argc; j++)
			verify_filename(prefix, argv[j]);
	}

	if (i < argc)
		paths = get_pathspec(prefix, argv + i);
	else if (prefix) {
		paths = xcalloc(2, sizeof(const char *));
		paths[0] = prefix;
		paths[1] = NULL;
	}

	if (!use_index) {
		int hit;
		if (cached)
			die("--cached cannot be used with --no-index.");
		if (list.nr)
			die("--no-index cannot be used with revs.");
		hit = grep_directory(&opt, paths);
		if (use_threads)
			hit |= wait_all();
		return !hit;
	}

	if (!list.nr) {
		int hit;
		if (!cached)
			setup_work_tree();

		hit = grep_cache(&opt, paths, cached);
		if (use_threads)
			hit |= wait_all();
		return !hit;
	}

	if (cached)
		die("both --cached and trees are given.");

	for (i = 0; i < list.nr; i++) {
		struct object *real_obj;
		real_obj = deref_tag(list.objects[i].item, NULL, 0);
		if (grep_object(&opt, paths, real_obj, list.objects[i].name)) {
			hit = 1;
			if (opt.status_only)
				break;
		}
	}

	if (use_threads)
		hit |= wait_all();
	free_grep_patterns(&opt);
	return !hit;
}

static void shortlog(const char *name,
		     struct origin_data *origin_data,
		     struct commit *head,
		     struct rev_info *rev, int limit,
		     struct strbuf *out)
{
	int i, count = 0;
	struct commit *commit;
	struct object *branch;
	struct string_list subjects = STRING_LIST_INIT_DUP;
	struct string_list authors = STRING_LIST_INIT_DUP;
	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;

	branch = deref_tag(parse_object(sha1), sha1_to_hex(sha1), 40);
	if (!branch || branch->type != OBJ_COMMIT)
		return;

	setup_revisions(0, NULL, rev, NULL);
	add_pending_object(rev, branch, name);
	add_pending_object(rev, &head->object, "^HEAD");
	head->object.flags |= UNINTERESTING;
	if (prepare_revision_walk(rev))
		die("revision walk setup failed");
	while ((commit = get_revision(rev)) != NULL) {
		struct pretty_print_context ctx = {0};

		if (commit->parents && commit->parents->next) {
			/* do not list a merge but count committer */
			record_person('c', &committers, commit);
			continue;
		}
		if (!count)
			/* the 'tip' committer */
			record_person('c', &committers, commit);
		record_person('a', &authors, commit);
		count++;
		if (subjects.nr > limit)
			continue;

		format_commit_message(commit, "%s", &sb, &ctx);
		strbuf_ltrim(&sb);

		if (!sb.len)
			string_list_append(&subjects,
					   sha1_to_hex(commit->object.sha1));
		else
			string_list_append(&subjects, strbuf_detach(&sb, NULL));
	}

	add_people_info(out, &authors, &committers);
	if (count > limit)
		strbuf_addf(out, "\n* %s: (%d commits)\n", name, count);
	else
		strbuf_addf(out, "\n* %s:\n", name);

	if (origin_data->is_local_branch && use_branch_desc)
		add_branch_desc(out, name);

	for (i = 0; i < subjects.nr; i++)
		if (i >= limit)
			strbuf_addf(out, "  ...\n");
		else
			strbuf_addf(out, "  %s\n", subjects.items[i].string);

	clear_commit_marks((struct commit *)branch, flags);
	clear_commit_marks(head, flags);
	free_commit_list(rev->commits);
	rev->commits = NULL;
	rev->pending.nr = 0;

	string_list_clear(&authors, 0);
	string_list_clear(&committers, 0);
	string_list_clear(&subjects, 0);
}

static int show_ref(const char *refname, const unsigned char *sha1, int flag, void *cbdata)
{
	struct object *obj;
	const char *hex;
	unsigned char peeled[20];

	if (tags_only || heads_only) {
		int match;

		match = heads_only && !prefixcmp(refname, "refs/heads/");
		match |= tags_only && !prefixcmp(refname, "refs/tags/");
		if (!match)
			return 0;
	}
	if (pattern) {
		int reflen = strlen(refname);
		const char **p = pattern, *m;
		while ((m = *p++) != NULL) {
			int len = strlen(m);
			if (len > reflen)
				continue;
			if (memcmp(m, refname + reflen - len, len))
				continue;
			if (len == reflen)
				goto match;
			/* "--verify" requires an exact match */
			if (verify)
				continue;
			if (refname[reflen - len - 1] == '/')
				goto match;
		}
		return 0;
	}

match:
	found_match++;

	/* This changes the semantics slightly that even under quiet we
	 * detect and return error if the repository is corrupt and
	 * ref points at a nonexistent object.
	 */
	if (!has_sha1_file(sha1))
		die("git show-ref: bad ref %s (%s)", refname,
		    sha1_to_hex(sha1));

	if (quiet)
		return 0;

	show_one(refname, sha1);

	if (!deref_tags)
		return 0;

	if ((flag & REF_ISPACKED) && !peel_ref(refname, peeled)) {
		if (!is_null_sha1(peeled)) {
			hex = find_unique_abbrev(peeled, abbrev);
			printf("%s %s^{}\n", hex, refname);
		}
	}
	else {
		obj = parse_object(sha1);
		if (!obj)
			die("git show-ref: bad ref %s (%s)", refname,
			    sha1_to_hex(sha1));
		if (obj->type == OBJ_TAG) {
			obj = deref_tag(obj, refname, 0);
			if (!obj)
				die("git show-ref: bad tag at ref %s (%s)", refname,
				    sha1_to_hex(sha1));
			hex = find_unique_abbrev(obj->sha1, abbrev);
			printf("%s %s^{}\n", hex, refname);
		}
	}
	return 0;
}

static void shortlog(const char *name, unsigned char *sha1,
		struct commit *head, struct rev_info *rev, int limit)
{
	int i, count = 0;
	struct commit *commit;
	struct object *branch;
	struct list subjects = { NULL, NULL, 0, 0 };
	int flags = UNINTERESTING | TREESAME | SEEN | SHOWN | ADDED;

	branch = deref_tag(parse_object(sha1), sha1_to_hex(sha1), 40);
	if (!branch || branch->type != OBJ_COMMIT)
		return;

	setup_revisions(0, NULL, rev, NULL);
	rev->ignore_merges = 1;
	add_pending_object(rev, branch, name);
	add_pending_object(rev, &head->object, "^HEAD");
	head->object.flags |= UNINTERESTING;
	if (prepare_revision_walk(rev))
		die("revision walk setup failed");
	while ((commit = get_revision(rev)) != NULL) {
		char *oneline, *bol, *eol;

		/* ignore merges */
		if (commit->parents && commit->parents->next)
			continue;

		count++;
		if (subjects.nr > limit)
			continue;

		bol = strstr(commit->buffer, "\n\n");
		if (bol) {
			unsigned char c;
			do {
				c = *++bol;
			} while (isspace(c));
			if (!c)
				bol = NULL;
		}

		if (!bol) {
			append_to_list(&subjects, xstrdup(sha1_to_hex(
							commit->object.sha1)),
					NULL);
			continue;
		}

		eol = strchr(bol, '\n');
		if (eol) {
			oneline = xmemdupz(bol, eol - bol);
		} else {
			oneline = xstrdup(bol);
		}
		append_to_list(&subjects, oneline, NULL);
	}

	if (count > limit)
		printf("\n* %s: (%d commits)\n", name, count);
	else
		printf("\n* %s:\n", name);

	for (i = 0; i < subjects.nr; i++)
		if (i >= limit)
			printf("  ...\n");
		else
			printf("  %s\n", subjects.list[i]);

	clear_commit_marks((struct commit *)branch, flags);
	clear_commit_marks(head, flags);
	free_commit_list(rev->commits);
	rev->commits = NULL;
	rev->pending.nr = 0;

	free_list(&subjects);
}

static int peel_onion(const char *name, int len, unsigned char *sha1)
{
	unsigned char outer[20];
	const char *sp;
	const char *type_string = NULL;
	struct object *o;

	/*
	 * "ref^{type}" dereferences ref repeatedly until you cannot
	 * dereference anymore, or you get an object of given type,
	 * whichever comes first.  "ref^{}" means just dereference
	 * tags until you get a non-tag.  "ref^0" is a shorthand for
	 * "ref^{commit}".  "commit^{tree}" could be used to find the
	 * top-level tree of the given commit.
	 */
	if (len < 4 || name[len-1] != '}')
		return -1;

	for (sp = name + len - 1; name <= sp; sp--) {
		int ch = *sp;
		if (ch == '{' && name < sp && sp[-1] == '^')
			break;
	}
	if (sp <= name)
		return -1;

	sp++; /* beginning of type name, or closing brace for empty */
	if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
		type_string = commit_type;
	else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
		type_string = tree_type;
	else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
		type_string = blob_type;
	else if (sp[0] == '}')
		type_string = NULL;
	else
		return -1;

	if (get_sha1_1(name, sp - name - 2, outer))
		return -1;

	o = parse_object(outer);
	if (!o)
		return -1;
	if (!type_string) {
		o = deref_tag(o, name, sp - name - 2);
		if (!o || (!o->parsed && !parse_object(o->sha1)))
			return -1;
		memcpy(sha1, o->sha1, 20);
	}
	else {
		/* At this point, the syntax look correct, so
		 * if we do not get the needed object, we should
		 * barf.
		 */

		while (1) {
			if (!o || (!o->parsed && !parse_object(o->sha1)))
				return -1;
			if (o->type == type_string) {
				memcpy(sha1, o->sha1, 20);
				return 0;
			}
			if (o->type == tag_type)
				o = ((struct tag*) o)->tagged;
			else if (o->type == commit_type)
				o = &(((struct commit *) o)->tree->object);
			else
				return error("%.*s: expected %s type, but the object dereferences to %s type",
					     len, name, type_string,
					     o->type);
			if (!o->parsed)
				parse_object(o->sha1);
		}
	}
	return 0;
}