static int refresh(struct refresh_params *o, unsigned int flag)
{
	setup_work_tree();
	read_cache_preload(NULL);
	*o->has_errors |= refresh_cache(o->flags | flag);
	return 0;
}

static int checkout(void)
{
	unsigned char sha1[20];
	char *head;
	struct lock_file *lock_file;
	struct unpack_trees_options opts;
	struct tree *tree;
	struct tree_desc t;
	int err = 0, fd;

	if (option_no_checkout)
		return 0;

	head = resolve_refdup("HEAD", sha1, 1, NULL);
	if (!head) {
		warning(_("remote HEAD refers to nonexistent ref, "
			  "unable to checkout.\n"));
		return 0;
	}
	if (!strcmp(head, "HEAD")) {
		if (advice_detached_head)
			detach_advice(sha1_to_hex(sha1));
	} else {
		if (prefixcmp(head, "refs/heads/"))
			die(_("HEAD not found below refs/heads!"));
	}
	free(head);

	/* We need to be in the new work tree for the checkout */
	setup_work_tree();

	lock_file = xcalloc(1, sizeof(struct lock_file));
	fd = hold_locked_index(lock_file, 1);

	memset(&opts, 0, sizeof opts);
	opts.update = 1;
	opts.merge = 1;
	opts.fn = oneway_merge;
	opts.verbose_update = (option_verbosity >= 0);
	opts.src_index = &the_index;
	opts.dst_index = &the_index;

	tree = parse_tree_indirect(sha1);
	parse_tree(tree);
	init_tree_desc(&t, tree->buffer, tree->size);
	if (unpack_trees(1, &t, &opts) < 0)
		die(_("unable to checkout working tree"));

	if (write_cache(fd, active_cache, active_nr) ||
	    commit_locked_index(lock_file))
		die(_("unable to write new index file"));

	err |= run_hook(NULL, "post-checkout", sha1_to_hex(null_sha1),
			sha1_to_hex(sha1), "1", NULL);

	if (!err && option_recursive)
		err = run_command_v_opt(argv_submodule, RUN_GIT_CMD);

	return err;
}

static int builtin_diff_index(struct rev_info *revs,
			      int argc, const char **argv)
{
	int cached = 0;
	while (1 < argc) {
		const char *arg = argv[1];
		if (!strcmp(arg, "--cached") || !strcmp(arg, "--staged"))
			cached = 1;
		else
			usage(builtin_diff_usage);
		argv++; argc--;
	}
	if (!cached)
		setup_work_tree();
	/*
	 * Make sure there is one revision (i.e. pending object),
	 * and there is no revision filtering parameters.
	 */
	if (revs->pending.nr != 1 ||
	    revs->max_count != -1 || revs->min_age != -1 ||
	    revs->max_age != -1)
		usage(builtin_diff_usage);
	if (read_cache_preload(revs->diffopt.pathspec.raw) < 0) {
		perror("read_cache_preload");
		return -1;
	}
	return run_diff_index(revs, cached);
}

static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
{
	int status, help;
	struct stat st;
	const char *prefix;

	prefix = NULL;
	help = argc == 2 && !strcmp(argv[1], "-h");
	if (!help) {
		if (p->option & RUN_SETUP)
			prefix = setup_git_directory();
		else if (p->option & RUN_SETUP_GENTLY) {
			int nongit_ok;
			prefix = setup_git_directory_gently(&nongit_ok);
		}

		if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
			use_pager = check_pager_config(p->cmd);
		if (use_pager == -1 && p->option & USE_PAGER)
			use_pager = 1;

		if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
		    startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
			trace_repo_setup(prefix);
	}
	commit_pager_choice();

	if (!help && get_super_prefix()) {
		if (!(p->option & SUPPORT_SUPER_PREFIX))
			die("%s doesn't support --super-prefix", p->cmd);
		if (prefix)
			die("can't use --super-prefix from a subdirectory");
	}

	if (!help && p->option & NEED_WORK_TREE)
		setup_work_tree();

	trace_argv_printf(argv, "trace: built-in: git");

	status = p->fn(argc, argv, prefix);
	if (status)
		return status;

	/* Somebody closed stdout? */
	if (fstat(fileno(stdout), &st))
		return 0;
	/* Ignore write errors for pipes and sockets.. */
	if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
		return 0;

	/* Check for ENOSPC and EIO errors.. */
	if (fflush(stdout))
		die_errno("write failure on standard output");
	if (ferror(stdout))
		die("unknown write failure on standard output");
	if (fclose(stdout))
		die_errno("close failed on standard output");
	return 0;
}

static void wt_status_print_verbose(struct wt_status *s)
{
	struct rev_info rev;
	struct setup_revision_opt opt;
	int dirty_submodules;
	const char *c = color(WT_STATUS_HEADER, s);

	init_revisions(&rev, NULL);
	DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);

	memset(&opt, 0, sizeof(opt));
	opt.def = s->is_initial ? EMPTY_TREE_SHA1_HEX : s->reference;
	setup_revisions(0, NULL, &rev, &opt);

	rev.diffopt.output_format |= DIFF_FORMAT_PATCH;
	rev.diffopt.detect_rename = 1;
	rev.diffopt.file = s->fp;
	rev.diffopt.close_file = 0;
	/*
	 * If we're not going to stdout, then we definitely don't
	 * want color, since we are going to the commit message
	 * file (and even the "auto" setting won't work, since it
	 * will have checked isatty on stdout). But we then do want
	 * to insert the scissor line here to reliably remove the
	 * diff before committing.
	 */
	if (s->fp != stdout) {
		rev.diffopt.use_color = 0;
		wt_status_add_cut_line(s->fp);
	}
	if (s->verbose > 1 && s->commitable) {
		/* print_updated() printed a header, so do we */
		if (s->fp != stdout)
			wt_status_print_trailer(s);
		status_printf_ln(s, c, _("Changes to be committed:"));
		rev.diffopt.a_prefix = "c/";
		rev.diffopt.b_prefix = "i/";
	} /* else use prefix as per user config */
	run_diff_index(&rev, 1);
	if (s->verbose > 1 &&
	    wt_status_check_worktree_changes(s, &dirty_submodules)) {
		status_printf_ln(s, c,
			"--------------------------------------------------");
		status_printf_ln(s, c, _("Changes not staged for commit:"));
		setup_work_tree();
		rev.diffopt.a_prefix = "i/";
		rev.diffopt.b_prefix = "w/";
		run_diff_files(&rev, 0);
	}
}

static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
{
	int status, help;
	struct stat st;
	const char *prefix;

	prefix = NULL;
	help = argc == 2 && !strcmp(argv[1], "-h");
	if (!help) {
		if (p->option & RUN_SETUP)
			prefix = setup_git_directory();
		if (p->option & RUN_SETUP_GENTLY) {
			int nongit_ok;
			prefix = setup_git_directory_gently(&nongit_ok);
		}

		if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
			use_pager = check_pager_config(p->cmd);
		if (use_pager == -1 && p->option & USE_PAGER)
			use_pager = 1;
	}
	commit_pager_choice();

	if (!help && p->option & NEED_WORK_TREE)
		setup_work_tree();

	trace_argv_printf(argv, "trace: built-in: git");

	status = p->fn(argc, argv, prefix);
	if (status)
		return status;

	/* Somebody closed stdout? */
	if (fstat(fileno(stdout), &st))
		return 0;
	/* Ignore write errors for pipes and sockets.. */
	if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
		return 0;

	/* Check for ENOSPC and EIO errors.. */
	if (fflush(stdout))
		die_errno("write failure on standard output");
	if (ferror(stdout))
		die("unknown write failure on standard output");
	if (fclose(stdout))
		die_errno("close failed on standard output");
	return 0;
}

int cmd_diff_index(int argc, const char **argv, const char *prefix)
{
	struct rev_info rev;
	int cached = 0;
	int i;
	int result;

	if (argc == 2 && !strcmp(argv[1], "-h"))
		usage(diff_cache_usage);

	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
	init_revisions(&rev, prefix);
	rev.abbrev = 0;
	precompose_argv(argc, argv);

	argc = setup_revisions(argc, argv, &rev, NULL);
	for (i = 1; i < argc; i++) {
		const char *arg = argv[i];

		if (!strcmp(arg, "--cached"))
			cached = 1;
		else
			usage(diff_cache_usage);
	}
	if (!rev.diffopt.output_format)
		rev.diffopt.output_format = DIFF_FORMAT_RAW;

	/*
	 * Make sure there is one revision (i.e. pending object),
	 * and there is no revision filtering parameters.
	 */
	if (rev.pending.nr != 1 ||
	    rev.max_count != -1 || rev.min_age != -1 || rev.max_age != -1)
		usage(diff_cache_usage);
	if (!cached) {
		setup_work_tree();
		if (read_cache_preload(&rev.diffopt.pathspec) < 0) {
			perror("read_cache_preload");
			return -1;
		}
	} else if (read_cache() < 0) {
		perror("read_cache");
		return -1;
	}
	result = run_diff_index(&rev, cached);
	UNLEAK(rev);
	return diff_result_code(&rev.diffopt, result);
}

int cmd_main(int argc, const char **argv)
{
	struct child_process cp = CHILD_PROCESS_INIT;
	int nogit = 0;

	setup_git_directory_gently(&nogit);
	if (nogit)
		die("No git repo found");
	if (argc > 1 && !strcmp(argv[1], "--setup-work-tree")) {
		setup_work_tree();
		argv++;
	}
	cp.git_cmd = 1;
	cp.argv = (const char **)argv + 1;
	return run_command(&cp);
}

static int reupdate_callback(struct parse_opt_ctx_t *ctx,
				const struct option *opt, int flags)
{
	int *has_errors = opt->value;
	const char *prefix = startup_info->prefix;

	/* consume remaining arguments. */
	setup_work_tree();
	*has_errors = do_reupdate(ctx->argc, ctx->argv,
				prefix, prefix ? strlen(prefix) : 0);
	if (*has_errors)
		active_cache_changed = 0;

	ctx->argv += ctx->argc - 1;
	ctx->argc = 1;
	return 0;
}

int main(int argc, char **argv)
{
	struct child_process cp;
	int nogit = 0;

	setup_git_directory_gently(&nogit);
	if (nogit)
		die("No git repo found");
	if (!strcmp(argv[1], "--setup-work-tree")) {
		setup_work_tree();
		argv++;
	}
	memset(&cp, 0, sizeof(cp));
	cp.git_cmd = 1;
	cp.argv = (const char **)argv+1;
	return run_command(&cp);
}

static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
{
    int result;
    unsigned int options = 0;

    while (1 < argc && argv[1][0] == '-') {
        if (!strcmp(argv[1], "--base"))
            revs->max_count = 1;
        else if (!strcmp(argv[1], "--ours"))
            revs->max_count = 2;
        else if (!strcmp(argv[1], "--theirs"))
            revs->max_count = 3;
        else if (!strcmp(argv[1], "-q"))
            options |= DIFF_SILENT_ON_REMOVED;
        else if (!strcmp(argv[1], "-h"))
            usage(builtin_diff_usage);
        else
            return error("invalid option: %s", argv[1]);
        argv++;
        argc--;
    }

    /*
     * "diff --base" should not combine merges because it was not
     * asked to.  "diff -c" should not densify (if the user wants
     * dense one, --cc can be explicitly asked for, or just rely
     * on the default).
     */
    if (revs->max_count == -1 && !revs->combine_merges &&
            (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
        revs->combine_merges = revs->dense_combined_merges = 1;

    setup_work_tree();
    if (read_cache_preload(revs->diffopt.paths) < 0) {
        perror("read_cache_preload");
        return -1;
    }
    result = run_diff_files(revs, options);
    return diff_result_code(&revs->diffopt, result);
}

//.........这里部分代码省略.........

	/* We can't free this memory, it becomes part of a linked list parsed atexit() */
	lock_file = xcalloc(1, sizeof(struct lock_file));

	newfd = hold_locked_index(lock_file, 0);
	if (newfd < 0)
		lock_error = errno;

	entries = read_cache();
	if (entries < 0)
		die("cache corrupted");

	/*
	 * Custom copy of parse_options() because we want to handle
	 * filename arguments as they come.
	 */
	parse_options_start(&ctx, argc, argv, prefix,
			    options, PARSE_OPT_STOP_AT_NON_OPTION);
	while (ctx.argc) {
		if (parseopt_state != PARSE_OPT_DONE)
			parseopt_state = parse_options_step(&ctx, options,
							    update_index_usage);
		if (!ctx.argc)
			break;
		switch (parseopt_state) {
		case PARSE_OPT_HELP:
			exit(129);
		case PARSE_OPT_NON_OPTION:
		case PARSE_OPT_DONE:
		{
			const char *path = ctx.argv[0];
			const char *p;

			setup_work_tree();
			p = prefix_path(prefix, prefix_length, path);
			update_one(p);
			if (set_executable_bit)
				chmod_path(set_executable_bit, p);
			free((char *)p);
			ctx.argc--;
			ctx.argv++;
			break;
		}
		case PARSE_OPT_UNKNOWN:
			if (ctx.argv[0][1] == '-')
				error("unknown option '%s'", ctx.argv[0] + 2);
			else
				error("unknown switch '%c'", *ctx.opt);
			usage_with_options(update_index_usage, options);
		}
	}
	argc = parse_options_end(&ctx);
	if (preferred_index_format) {
		if (preferred_index_format < INDEX_FORMAT_LB ||
		    INDEX_FORMAT_UB < preferred_index_format)
			die("index-version %d not in range: %d..%d",
			    preferred_index_format,
			    INDEX_FORMAT_LB, INDEX_FORMAT_UB);

		if (the_index.version != preferred_index_format)
			active_cache_changed |= SOMETHING_CHANGED;
		the_index.version = preferred_index_format;
	}

	if (read_from_stdin) {
		struct strbuf buf = STRBUF_INIT, nbuf = STRBUF_INIT;

int cmd_merge(int argc, const char **argv, const char *prefix)
{
	unsigned char result_tree[20];
	struct strbuf buf = STRBUF_INIT;
	const char *head_arg;
	int flag, head_invalid = 0, i;
	int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
	struct commit_list *common = NULL;
	const char *best_strategy = NULL, *wt_strategy = NULL;
	struct commit_list **remotes = &remoteheads;

	setup_work_tree();
	if (file_exists(git_path("MERGE_HEAD")))
		die("You have not concluded your merge. (MERGE_HEAD exists)");
	if (read_cache_unmerged())
		die("You are in the middle of a conflicted merge."
				" (index unmerged)");

	/*
	 * Check if we are _not_ on a detached HEAD, i.e. if there is a
	 * current branch.
	 */
	branch = resolve_ref("HEAD", head, 0, &flag);
	if (branch && !prefixcmp(branch, "refs/heads/"))
		branch += 11;
	if (is_null_sha1(head))
		head_invalid = 1;

	git_config(git_merge_config, NULL);

	/* for color.ui */
	if (diff_use_color_default == -1)
		diff_use_color_default = git_use_color_default;

	argc = parse_options(argc, argv, prefix, builtin_merge_options,
			builtin_merge_usage, 0);
	if (verbosity < 0)
		show_diffstat = 0;

	if (squash) {
		if (!allow_fast_forward)
			die("You cannot combine --squash with --no-ff.");
		option_commit = 0;
	}

	if (!argc)
		usage_with_options(builtin_merge_usage,
			builtin_merge_options);

	/*
	 * This could be traditional "merge <msg> HEAD <commit>..."  and
	 * the way we can tell it is to see if the second token is HEAD,
	 * but some people might have misused the interface and used a
	 * committish that is the same as HEAD there instead.
	 * Traditional format never would have "-m" so it is an
	 * additional safety measure to check for it.
	 */

	if (!have_message && is_old_style_invocation(argc, argv)) {
		strbuf_addstr(&merge_msg, argv[0]);
		head_arg = argv[1];
		argv += 2;
		argc -= 2;
	} else if (head_invalid) {
		struct object *remote_head;
		/*
		 * If the merged head is a valid one there is no reason
		 * to forbid "git merge" into a branch yet to be born.
		 * We do the same for "git pull".
		 */
		if (argc != 1)
			die("Can merge only exactly one commit into "
				"empty head");
		if (squash)
			die("Squash commit into empty head not supported yet");
		if (!allow_fast_forward)
			die("Non-fast-forward commit does not make sense into "
			    "an empty head");
		remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
		if (!remote_head)
			die("%s - not something we can merge", argv[0]);
		update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
				DIE_ON_ERR);
		reset_hard(remote_head->sha1, 0);
		return 0;
	} else {
		struct strbuf msg = STRBUF_INIT;

		/* We are invoked directly as the first-class UI. */
		head_arg = "HEAD";

		/*
		 * All the rest are the commits being merged;
		 * prepare the standard merge summary message to
		 * be appended to the given message.  If remote
		 * is invalid we will die later in the common
		 * codepath so we discard the error in this
		 * loop.
		 */
		for (i = 0; i < argc; i++)
//.........这里部分代码省略.........

int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
{
	int i, newfd, stage = 0;
	unsigned char sha1[20];
	struct tree_desc t[MAX_UNPACK_TREES];
	struct unpack_trees_options opts;
	int prefix_set = 0;
	const struct option read_tree_options[] = {
		{ OPTION_CALLBACK, 0, "index-output", NULL, N_("file"),
		  N_("write resulting index to <file>"),
		  PARSE_OPT_NONEG, index_output_cb },
		OPT_SET_INT(0, "empty", &read_empty,
			    N_("only empty the index"), 1),
		OPT__VERBOSE(&opts.verbose_update, N_("be verbose")),
		OPT_GROUP(N_("Merging")),
		OPT_SET_INT('m', NULL, &opts.merge,
			    N_("perform a merge in addition to a read"), 1),
		OPT_SET_INT(0, "trivial", &opts.trivial_merges_only,
			    N_("3-way merge if no file level merging required"), 1),
		OPT_SET_INT(0, "aggressive", &opts.aggressive,
			    N_("3-way merge in presence of adds and removes"), 1),
		OPT_SET_INT(0, "reset", &opts.reset,
			    N_("same as -m, but discard unmerged entries"), 1),
		{ OPTION_STRING, 0, "prefix", &opts.prefix, N_("<subdirectory>/"),
		  N_("read the tree into the index under <subdirectory>/"),
		  PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP },
		OPT_SET_INT('u', NULL, &opts.update,
			    N_("update working tree with merge result"), 1),
		{ OPTION_CALLBACK, 0, "exclude-per-directory", &opts,
		  N_("gitignore"),
		  N_("allow explicitly ignored files to be overwritten"),
		  PARSE_OPT_NONEG, exclude_per_directory_cb },
		OPT_SET_INT('i', NULL, &opts.index_only,
			    N_("don't check the working tree after merging"), 1),
		OPT__DRY_RUN(&opts.dry_run, N_("don't update the index or the work tree")),
		OPT_SET_INT(0, "no-sparse-checkout", &opts.skip_sparse_checkout,
			    N_("skip applying sparse checkout filter"), 1),
		OPT_SET_INT(0, "debug-unpack", &opts.debug_unpack,
			    N_("debug unpack-trees"), 1),
		OPT_END()
	};

	memset(&opts, 0, sizeof(opts));
	opts.head_idx = -1;
	opts.src_index = &the_index;
	opts.dst_index = &the_index;

	git_config(git_default_config, NULL);

	argc = parse_options(argc, argv, unused_prefix, read_tree_options,
			     read_tree_usage, 0);

	newfd = hold_locked_index(&lock_file, 1);

	prefix_set = opts.prefix ? 1 : 0;
	if (1 < opts.merge + opts.reset + prefix_set)
		die("Which one? -m, --reset, or --prefix?");

	if (opts.reset || opts.merge || opts.prefix) {
		if (read_cache_unmerged() && (opts.prefix || opts.merge))
			die("You need to resolve your current index first");
		stage = opts.merge = 1;
	}
	resolve_undo_clear();

	for (i = 0; i < argc; i++) {
		const char *arg = argv[i];

		if (get_sha1(arg, sha1))
			die("Not a valid object name %s", arg);
		if (list_tree(sha1) < 0)
			die("failed to unpack tree object %s", arg);
		stage++;
	}
	if (nr_trees == 0 && !read_empty)
		warning("read-tree: emptying the index with no arguments is deprecated; use --empty");
	else if (nr_trees > 0 && read_empty)
		die("passing trees as arguments contradicts --empty");

	if (1 < opts.index_only + opts.update)
		die("-u and -i at the same time makes no sense");
	if ((opts.update||opts.index_only) && !opts.merge)
		die("%s is meaningless without -m, --reset, or --prefix",
		    opts.update ? "-u" : "-i");
	if ((opts.dir && !opts.update))
		die("--exclude-per-directory is meaningless unless -u");
	if (opts.merge && !opts.index_only)
		setup_work_tree();

	if (opts.merge) {
		if (stage < 2)
			die("just how do you expect me to merge %d trees?", stage-1);
		switch (stage - 1) {
		case 1:
			opts.fn = opts.prefix ? bind_merge : oneway_merge;
			break;
		case 2:
			opts.fn = twoway_merge;
			opts.initial_checkout = is_cache_unborn();
			break;
//.........这里部分代码省略.........

int cmd_check_attr(int argc, const char **argv, const char *prefix)
{
	struct git_attr_check *check;
	int cnt, i, doubledash, filei;

	if (!is_bare_repository())
		setup_work_tree();

	git_config(git_default_config, NULL);

	argc = parse_options(argc, argv, prefix, check_attr_options,
			     check_attr_usage, PARSE_OPT_KEEP_DASHDASH);

	if (read_cache() < 0) {
		die("invalid cache");
	}

	if (cached_attrs)
		git_attr_set_direction(GIT_ATTR_INDEX, NULL);

	doubledash = -1;
	for (i = 0; doubledash < 0 && i < argc; i++) {
		if (!strcmp(argv[i], "--"))
			doubledash = i;
	}

	/* Process --all and/or attribute arguments: */
	if (all_attrs) {
		if (doubledash >= 1)
			error_with_usage("Attributes and --all both specified");

		cnt = 0;
		filei = doubledash + 1;
	} else if (doubledash == 0) {
		error_with_usage("No attribute specified");
	} else if (doubledash < 0) {
		if (!argc)
			error_with_usage("No attribute specified");

		if (stdin_paths) {
			/* Treat all arguments as attribute names. */
			cnt = argc;
			filei = argc;
		} else {
			/* Treat exactly one argument as an attribute name. */
			cnt = 1;
			filei = 1;
		}
	} else {
		cnt = doubledash;
		filei = doubledash + 1;
	}

	/* Check file argument(s): */
	if (stdin_paths) {
		if (filei < argc)
			error_with_usage("Can't specify files with --stdin");
	} else {
		if (filei >= argc)
			error_with_usage("No file specified");
	}

	if (all_attrs) {
		check = NULL;
	} else {
		check = xcalloc(cnt, sizeof(*check));
		for (i = 0; i < cnt; i++) {
			const char *name;
			struct git_attr *a;
			name = argv[i];
			a = git_attr(name);
			if (!a)
				return error("%s: not a valid attribute name",
					name);
			check[i].attr = a;
		}
	}

	if (stdin_paths)
		check_attr_stdin_paths(prefix, cnt, check);
	else {
		for (i = filei; i < argc; i++)
			check_attr(prefix, cnt, check, argv[i]);
		maybe_flush_or_die(stdout, "attribute to stdout");
	}
	return 0;
}

//.........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;
}

int cmd_ls_files(int argc, const char **argv, const char *prefix)
{
	int require_work_tree = 0, show_tag = 0;
	struct dir_struct dir;
	struct option builtin_ls_files_options[] = {
		{ OPTION_CALLBACK, 'z', NULL, NULL, NULL,
			"paths are separated with NUL character",
			PARSE_OPT_NOARG, option_parse_z },
		OPT_BOOLEAN('t', NULL, &show_tag,
			"identify the file status with tags"),
		OPT_BOOLEAN('v', NULL, &show_valid_bit,
			"use lowercase letters for 'assume unchanged' files"),
		OPT_BOOLEAN('c', "cached", &show_cached,
			"show cached files in the output (default)"),
		OPT_BOOLEAN('d', "deleted", &show_deleted,
			"show deleted files in the output"),
		OPT_BOOLEAN('m', "modified", &show_modified,
			"show modified files in the output"),
		OPT_BOOLEAN('o', "others", &show_others,
			"show other files in the output"),
		OPT_BIT('i', "ignored", &dir.flags,
			"show ignored files in the output",
			DIR_SHOW_IGNORED),
		OPT_BOOLEAN('s', "stage", &show_stage,
			"show staged contents' object name in the output"),
		OPT_BOOLEAN('k', "killed", &show_killed,
			"show files on the filesystem that need to be removed"),
		OPT_BIT(0, "directory", &dir.flags,
			"show 'other' directories' name only",
			DIR_SHOW_OTHER_DIRECTORIES),
		OPT_NEGBIT(0, "empty-directory", &dir.flags,
			"don't show empty directories",
			DIR_HIDE_EMPTY_DIRECTORIES),
		OPT_BOOLEAN('u', "unmerged", &show_unmerged,
			"show unmerged files in the output"),
		OPT_BOOLEAN(0, "resolve-undo", &show_resolve_undo,
			    "show resolve-undo information"),
		{ OPTION_CALLBACK, 'x', "exclude", &dir.exclude_list[EXC_CMDL], "pattern",
			"skip files matching pattern",
			0, option_parse_exclude },
		{ OPTION_CALLBACK, 'X', "exclude-from", &dir, "file",
			"exclude patterns are read from <file>",
			0, option_parse_exclude_from },
		OPT_STRING(0, "exclude-per-directory", &dir.exclude_per_dir, "file",
			"read additional per-directory exclude patterns in <file>"),
		{ OPTION_CALLBACK, 0, "exclude-standard", &dir, NULL,
			"add the standard git exclusions",
			PARSE_OPT_NOARG, option_parse_exclude_standard },
		{ OPTION_SET_INT, 0, "full-name", &prefix_offset, NULL,
			"make the output relative to the project top directory",
			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL },
		OPT_BOOLEAN(0, "error-unmatch", &error_unmatch,
			"if any <file> is not in the index, treat this as an error"),
		OPT_STRING(0, "with-tree", &with_tree, "tree-ish",
			"pretend that paths removed since <tree-ish> are still present"),
		OPT__ABBREV(&abbrev),
		OPT_END()
	};

	memset(&dir, 0, sizeof(dir));
	if (prefix)
		prefix_offset = strlen(prefix);
	git_config(git_default_config, NULL);

	if (read_cache() < 0)
		die("index file corrupt");

	argc = parse_options(argc, argv, prefix, builtin_ls_files_options,
			ls_files_usage, 0);
	if (show_tag || show_valid_bit) {
		tag_cached = "H ";
		tag_unmerged = "M ";
		tag_removed = "R ";
		tag_modified = "C ";
		tag_other = "? ";
		tag_killed = "K ";
		tag_skip_worktree = "S ";
		tag_resolve_undo = "U ";
	}
	if (show_modified || show_others || show_deleted || (dir.flags & DIR_SHOW_IGNORED) || show_killed)
		require_work_tree = 1;
	if (show_unmerged)
		/*
		 * There's no point in showing unmerged unless
		 * you also show the stage information.
		 */
		show_stage = 1;
	if (dir.exclude_per_dir)
		exc_given = 1;

	if (require_work_tree && !is_inside_work_tree())
		setup_work_tree();

	pathspec = get_pathspec(prefix, argv);

	/* be nice with submodule paths ending in a slash */
	if (pathspec)
		strip_trailing_slash_from_submodules();

	/* Verify that the pathspec matches the prefix */
//.........这里部分代码省略.........

//.........这里部分代码省略.........

	parse_pathspec(&pathspec, 0,
		       PATHSPEC_PREFER_CWD |
		       (opt.max_depth != -1 ? PATHSPEC_MAXDEPTH_VALID : 0),
		       prefix, argv + i);
	pathspec.max_depth = opt.max_depth;
	pathspec.recursive = 1;
	pathspec.recurse_submodules = !!recurse_submodules;

#ifndef NO_PTHREADS
	if (list.nr || cached || show_in_pager)
		num_threads = 0;
	else if (num_threads == 0)
		num_threads = GREP_NUM_THREADS_DEFAULT;
	else if (num_threads < 0)
		die(_("invalid number of threads specified (%d)"), num_threads);
	if (num_threads == 1)
		num_threads = 0;
#else
	if (num_threads)
		warning(_("no threads support, ignoring --threads"));
	num_threads = 0;
#endif

	if (!num_threads)
		/*
		 * The compiled patterns on the main path are only
		 * used when not using threading. Otherwise
		 * start_threads() below calls compile_grep_patterns()
		 * for each thread.
		 */
		compile_grep_patterns(&opt);

#ifndef NO_PTHREADS
	if (num_threads) {
		if (!(opt.name_only || opt.unmatch_name_only || opt.count)
		    && (opt.pre_context || opt.post_context ||
			opt.file_break || opt.funcbody))
			skip_first_line = 1;
		start_threads(&opt);
	}
#endif

	if (show_in_pager && (cached || list.nr))
		die(_("--open-files-in-pager only works on the worktree"));

	if (show_in_pager && opt.pattern_list && !opt.pattern_list->next) {
		const char *pager = path_list.items[0].string;
		int len = strlen(pager);

		if (len > 4 && is_dir_sep(pager[len - 5]))
			pager += len - 4;

		if (opt.ignore_case && !strcmp("less", pager))
			string_list_append(&path_list, "-I");

		if (!strcmp("less", pager) || !strcmp("vi", pager)) {
			struct strbuf buf = STRBUF_INIT;
			strbuf_addf(&buf, "+/%s%s",
					strcmp("less", pager) ? "" : "*",
					opt.pattern_list->pattern);
			string_list_append(&path_list, buf.buf);
			strbuf_detach(&buf, NULL);
		}
	}

	if (recurse_submodules && (!use_index || untracked))
		die(_("option not supported with --recurse-submodules."));

	if (!show_in_pager && !opt.status_only)
		setup_pager();

	if (!use_index && (untracked || cached))
		die(_("--cached or --untracked cannot be used with --no-index."));

	if (!use_index || untracked) {
		int use_exclude = (opt_exclude < 0) ? use_index : !!opt_exclude;
		hit = grep_directory(&opt, &pathspec, use_exclude, use_index);
	} else if (0 <= opt_exclude) {
		die(_("--[no-]exclude-standard cannot be used for tracked contents."));
	} else if (!list.nr) {
		if (!cached)
			setup_work_tree();

		hit = grep_cache(&opt, the_repository, &pathspec, cached);
	} else {
		if (cached)
			die(_("both --cached and trees are given."));

		hit = grep_objects(&opt, &pathspec, the_repository, &list);
	}

	if (num_threads)
		hit |= wait_all();
	if (hit && show_in_pager)
		run_pager(&opt, prefix);
	clear_pathspec(&pathspec);
	free_grep_patterns(&opt);
	return !hit;
}

//.........这里部分代码省略.........
	git_config(git_default_config, NULL);

	/* we will diagnose later if it turns out that we need to update it */
	newfd = hold_locked_index(&lock_file, 0);
	if (newfd < 0)
		lock_error = errno;

	entries = read_cache();
	if (entries < 0)
		die("cache corrupted");

	/*
	 * Custom copy of parse_options() because we want to handle
	 * filename arguments as they come.
	 */
	parse_options_start(&ctx, argc, argv, prefix,
			    options, PARSE_OPT_STOP_AT_NON_OPTION);
	while (ctx.argc) {
		if (parseopt_state != PARSE_OPT_DONE)
			parseopt_state = parse_options_step(&ctx, options,
							    update_index_usage);
		if (!ctx.argc)
			break;
		switch (parseopt_state) {
		case PARSE_OPT_HELP:
		case PARSE_OPT_ERROR:
			exit(129);
		case PARSE_OPT_NON_OPTION:
		case PARSE_OPT_DONE:
		{
			const char *path = ctx.argv[0];
			char *p;

			setup_work_tree();
			p = prefix_path(prefix, prefix_length, path);
			update_one(p);
			if (set_executable_bit)
				chmod_path(set_executable_bit, p);
			free(p);
			ctx.argc--;
			ctx.argv++;
			break;
		}
		case PARSE_OPT_UNKNOWN:
			if (ctx.argv[0][1] == '-')
				error("unknown option '%s'", ctx.argv[0] + 2);
			else
				error("unknown switch '%c'", *ctx.opt);
			usage_with_options(update_index_usage, options);
		}
	}
	argc = parse_options_end(&ctx);

	getline_fn = nul_term_line ? strbuf_getline_nul : strbuf_getline_lf;
	if (preferred_index_format) {
		if (preferred_index_format < INDEX_FORMAT_LB ||
		    INDEX_FORMAT_UB < preferred_index_format)
			die("index-version %d not in range: %d..%d",
			    preferred_index_format,
			    INDEX_FORMAT_LB, INDEX_FORMAT_UB);

		if (the_index.version != preferred_index_format)
			active_cache_changed |= SOMETHING_CHANGED;
		the_index.version = preferred_index_format;
	}

//.........这里部分代码省略.........
			add_excludes_from_file(&dir, argv[++i]);
			continue;
		}
		if (!prefixcmp(arg, "--exclude-from=")) {
			exc_given = 1;
			add_excludes_from_file(&dir, arg+15);
			continue;
		}
		if (!prefixcmp(arg, "--exclude-per-directory=")) {
			exc_given = 1;
			dir.exclude_per_dir = arg + 24;
			continue;
		}
		if (!strcmp(arg, "--exclude-standard")) {
			exc_given = 1;
			setup_standard_excludes(&dir);
			continue;
		}
		if (!strcmp(arg, "--full-name")) {
			prefix_offset = 0;
			continue;
		}
		if (!strcmp(arg, "--error-unmatch")) {
			error_unmatch = 1;
			continue;
		}
		if (!prefixcmp(arg, "--with-tree=")) {
			with_tree = arg + 12;
			continue;
		}
		if (!prefixcmp(arg, "--abbrev=")) {
			abbrev = strtoul(arg+9, NULL, 10);
			if (abbrev && abbrev < MINIMUM_ABBREV)
				abbrev = MINIMUM_ABBREV;
			else if (abbrev > 40)
				abbrev = 40;
			continue;
		}
		if (!strcmp(arg, "--abbrev")) {
			abbrev = DEFAULT_ABBREV;
			continue;
		}
		if (*arg == '-')
			usage(ls_files_usage);
		break;
	}

	if (require_work_tree && !is_inside_work_tree())
		setup_work_tree();

	pathspec = get_pathspec(prefix, argv + i);

	/* Verify that the pathspec matches the prefix */
	if (pathspec)
		prefix = verify_pathspec(prefix);

	/* Treat unmatching pathspec elements as errors */
	if (pathspec && error_unmatch) {
		int num;
		for (num = 0; pathspec[num]; num++)
			;
		ps_matched = xcalloc(1, num);
	}

	if (dir.show_ignored && !exc_given) {
		fprintf(stderr, "%s: --ignored needs some exclude pattern\n",
			argv[0]);
		exit(1);
	}

	/* With no flags, we default to showing the cached files */
	if (!(show_stage | show_deleted | show_others | show_unmerged |
	      show_killed | show_modified))
		show_cached = 1;

	read_cache();
	if (prefix)
		prune_cache(prefix);
	if (with_tree) {
		/*
		 * Basic sanity check; show-stages and show-unmerged
		 * would not make any sense with this option.
		 */
		if (show_stage || show_unmerged)
			die("ls-files --with-tree is incompatible with -s or -u");
		overlay_tree_on_cache(with_tree, prefix);
	}
	show_files(&dir, prefix);

	if (ps_matched) {
		int bad;
		bad = report_path_error(ps_matched, pathspec, prefix_offset);
		if (bad)
			fprintf(stderr, "Did you forget to 'git add'?\n");