C++ parse_pathspec函数代码示例

static void parse_args(struct pathspec *pathspec,
		       const char **argv, const char *prefix,
		       int patch_mode,
		       const char **rev_ret)
{
	const char *rev = "HEAD";
	struct object_id unused;
	/*
	 * Possible arguments are:
	 *
	 * git reset [-opts] [<rev>]
	 * git reset [-opts] <tree> [<paths>...]
	 * git reset [-opts] <tree> -- [<paths>...]
	 * git reset [-opts] -- [<paths>...]
	 * git reset [-opts] <paths>...
	 *
	 * At this point, argv points immediately after [-opts].
	 */

	if (argv[0]) {
		if (!strcmp(argv[0], "--")) {
			argv++; /* reset to HEAD, possibly with paths */
		} else if (argv[1] && !strcmp(argv[1], "--")) {
			rev = argv[0];
			argv += 2;
		}
		/*
		 * Otherwise, argv[0] could be either <rev> or <paths> and
		 * has to be unambiguous. If there is a single argument, it
		 * can not be a tree
		 */
		else if ((!argv[1] && !get_oid_committish(argv[0], &unused)) ||
			 (argv[1] && !get_oid_treeish(argv[0], &unused))) {
			/*
			 * Ok, argv[0] looks like a commit/tree; it should not
			 * be a filename.
			 */
			verify_non_filename(prefix, argv[0]);
			rev = *argv++;
		} else {
			/* Otherwise we treat this as a filename */
			verify_filename(prefix, argv[0], 1);
		}
	}
	*rev_ret = rev;

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

	parse_pathspec(pathspec, 0,
		       PATHSPEC_PREFER_FULL |
		       (patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0),
		       prefix, argv);
}

static int path_exists(struct tree *tree, const char *path)
{
	const char *paths[] = { path, NULL };
	struct pathspec pathspec;
	int ret;

	parse_pathspec(&pathspec, 0, 0, "", paths);
	pathspec.recursive = 1;
	ret = read_tree_recursive(tree, "", 0, 0, &pathspec,
				  reject_entry, &pathspec);
	free_pathspec(&pathspec);
	return ret != 0;
}

static int do_reupdate(int ac, const char **av,
		       const char *prefix, int prefix_length)
{
	/* Read HEAD and run update-index on paths that are
	 * merged and already different between index and HEAD.
	 */
	int pos;
	int has_head = 1;
	struct pathspec pathspec;

	parse_pathspec(&pathspec, 0,
		       PATHSPEC_PREFER_CWD,
		       prefix, av + 1);

	if (read_ref("HEAD", &head_oid))
		/* If there is no HEAD, that means it is an initial
		 * commit.  Update everything in the index.
		 */
		has_head = 0;
 redo:
	for (pos = 0; pos < active_nr; pos++) {
		const struct cache_entry *ce = active_cache[pos];
		struct cache_entry *old = NULL;
		int save_nr;
		char *path;

		if (ce_stage(ce) || !ce_path_match(&the_index, ce, &pathspec, NULL))
			continue;
		if (has_head)
			old = read_one_ent(NULL, &head_oid,
					   ce->name, ce_namelen(ce), 0);
		if (old && ce->ce_mode == old->ce_mode &&
		    !oidcmp(&ce->oid, &old->oid)) {
			discard_cache_entry(old);
			continue; /* unchanged */
		}
		/* Be careful.  The working tree may not have the
		 * path anymore, in which case, under 'allow_remove',
		 * or worse yet 'allow_replace', active_nr may decrease.
		 */
		save_nr = active_nr;
		path = xstrdup(ce->name);
		update_one(path);
		free(path);
		discard_cache_entry(old);
		if (save_nr != active_nr)
			goto redo;
	}
	clear_pathspec(&pathspec);
	return 0;
}

static int path_exists(struct archiver_args *args, const char *path)
{
	const char *paths[] = { path, NULL };
	struct path_exists_context ctx;
	int ret;

	ctx.args = args;
	parse_pathspec(&ctx.pathspec, 0, 0, "", paths);
	ctx.pathspec.recursive = 1;
	ret = read_tree_recursive(args->tree, "", 0, 0, &ctx.pathspec,
				  reject_entry, &ctx);
	clear_pathspec(&ctx.pathspec);
	return ret != 0;
}

int interactive_add(int argc, const char **argv, const char *prefix, int patch)
{
	struct pathspec pathspec;

	parse_pathspec(&pathspec, 0,
		       PATHSPEC_PREFER_FULL |
		       PATHSPEC_SYMLINK_LEADING_PATH |
		       PATHSPEC_PREFIX_ORIGIN,
		       prefix, argv);

	return run_add_interactive(NULL,
				   patch ? "--patch" : NULL,
				   &pathspec);
}

int git_checkout_file(const char *ref, const char *path, const char *outputpath)
{
	struct cache_entry *ce;
	int ret;
	GIT_HASH sha1;
	struct tree * root;
	struct checkout state;
	struct pathspec pathspec;
	const char *matchbuf[1];
	ret = get_sha1(ref, sha1);
	if(ret)
		return ret;

	reprepare_packed_git();
	root = parse_tree_indirect(sha1);

	if(!root)
	{
		free_all_pack();
		return -1;
	}

	ce = xcalloc(1, cache_entry_size(strlen(path)));

	matchbuf[0] = NULL;
	parse_pathspec(&pathspec, PATHSPEC_ALL_MAGIC, PATHSPEC_PREFER_CWD, path, matchbuf);
	pathspec.items[0].nowildcard_len = pathspec.items[0].len;
	ret = read_tree_recursive(root, "", 0, 0, &pathspec, update_some, ce);
	free_pathspec(&pathspec);

	if(ret)
	{
		free_all_pack();
		free(ce);
		return ret;
	}
	memset(&state, 0, sizeof(state));
	state.force = 1;
	state.refresh_cache = 0;

	ret = write_entry(ce, outputpath, &state, 0);
	free_all_pack();
	free(ce);
	return ret;
}

static int phoenixfs_open(const char *path, struct fuse_file_info *fi)
{
	int rev, fd;
	FILE *infile, *fsfile;
	char fspath[PATH_MAX];
	struct file_record *fr;
	char sha1_digest[40];

	rev = parse_pathspec(xpath, path);
	build_xpath(fspath, xpath, 0);

	/* Skip zinflate for entries not in fstree */
	if (!(fr = find_fr(xpath, rev)))
		goto END;

	/* Build openpath by hand */
	print_sha1(sha1_digest, fr->sha1);
	sprintf(openpath, "%s/.git/loose/%s", ROOTENV->fsback, sha1_digest);
	if (access(openpath, F_OK) < 0) {
		/* Try extracting from packfile */
		sprintf(xpath, "%s/.git/loose", ROOTENV->fsback);
		if (unpack_entry(fr->sha1, xpath) < 0)
			return -ENOENT;
		else
			PHOENIXFS_DBG("open:: pack %s", sha1_digest);
	}
	else
		PHOENIXFS_DBG("open:: loose %s", sha1_digest);

	/* zinflate openpath onto fspath */
	PHOENIXFS_DBG("open:: zinflate %s onto %s", sha1_digest, fspath);
	if (!(infile = fopen(openpath, "rb")) ||
		!(fsfile = fopen(fspath, "wb+")))
		return -errno;
	if (zinflate(infile, fsfile) != Z_OK)
		PHOENIXFS_DBG("open:: zinflate issue");
	fclose(infile);
	fclose(fsfile);
END:
	if ((fd = open(fspath, fi->flags)) < 0)
		return -errno;
	fi->fh = fd;
	return 0;
}

static int module_list_compute(int argc, const char **argv,
			       const char *prefix,
			       struct pathspec *pathspec,
			       struct module_list *list)
{
	int i, result = 0;
	char *ps_matched = NULL;
	parse_pathspec(pathspec, 0,
		       PATHSPEC_PREFER_FULL |
		       PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP,
		       prefix, argv);

	if (pathspec->nr)
		ps_matched = xcalloc(pathspec->nr, 1);

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

	for (i = 0; i < active_nr; i++) {
		const struct cache_entry *ce = active_cache[i];

		if (!S_ISGITLINK(ce->ce_mode) ||
		    !match_pathspec(pathspec, ce->name, ce_namelen(ce),
				    0, ps_matched, 1))
			continue;

		ALLOC_GROW(list->entries, list->nr + 1, list->alloc);
		list->entries[list->nr++] = ce;
		while (i + 1 < active_nr &&
		       !strcmp(ce->name, active_cache[i + 1]->name))
			/*
			 * Skip entries with the same name in different stages
			 * to make sure an entry is returned only once.
			 */
			i++;
	}

	if (ps_matched && report_path_error(ps_matched, pathspec, prefix))
		result = -1;

	free(ps_matched);

	return result;
}

static void parse_pathspec_arg(const char **pathspec,
		struct archiver_args *ar_args)
{
	/*
	 * must be consistent with parse_pathspec in path_exists()
	 * Also if pathspec patterns are dependent, we're in big
	 * trouble as we test each one separately
	 */
	parse_pathspec(&ar_args->pathspec, 0,
		       PATHSPEC_PREFER_FULL,
		       "", pathspec);
	if (pathspec) {
		while (*pathspec) {
			if (**pathspec && !path_exists(ar_args->tree, *pathspec))
				die(_("pathspec '%s' did not match any files"), *pathspec);
			pathspec++;
		}
	}
}

int cmd_reset(int argc, const char **argv, const char *prefix)
{
	int reset_type = NONE, update_ref_status = 0, quiet = 0;
	int patch_mode = 0, nul_term_line = 0, read_from_stdin = 0, unborn;
	char **stdin_paths = NULL;
	int stdin_nr = 0, stdin_alloc = 0;
	const char *rev;
	struct object_id oid;
	struct pathspec pathspec;
	int intent_to_add = 0;
	const struct option options[] = {
		OPT__QUIET(&quiet, N_("be quiet, only report errors")),
		OPT_SET_INT(0, "mixed", &reset_type,
						N_("reset HEAD and index"), MIXED),
		OPT_SET_INT(0, "soft", &reset_type, N_("reset only HEAD"), SOFT),
		OPT_SET_INT(0, "hard", &reset_type,
				N_("reset HEAD, index and working tree"), HARD),
		OPT_SET_INT(0, "merge", &reset_type,
				N_("reset HEAD, index and working tree"), MERGE),
		OPT_SET_INT(0, "keep", &reset_type,
				N_("reset HEAD but keep local changes"), KEEP),
		{ OPTION_CALLBACK, 0, "recurse-submodules", NULL,
			    "reset", "control recursive updating of submodules",
			    PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
		OPT_BOOL('p', "patch", &patch_mode, N_("select hunks interactively")),
		OPT_BOOL('N', "intent-to-add", &intent_to_add,
				N_("record only the fact that removed paths will be added later")),
		OPT_BOOL('z', NULL, &nul_term_line,
			N_("EXPERIMENTAL: paths are separated with NUL character")),
		OPT_BOOL(0, "stdin", &read_from_stdin,
				N_("EXPERIMENTAL: read paths from <stdin>")),
		OPT_END()
	};

	git_config(git_reset_config, NULL);

	argc = parse_options(argc, argv, prefix, options, git_reset_usage,
						PARSE_OPT_KEEP_DASHDASH);
	parse_args(&pathspec, argv, prefix, patch_mode, &rev);

	if (read_from_stdin) {
		strbuf_getline_fn getline_fn = nul_term_line ?
			strbuf_getline_nul : strbuf_getline_lf;
		int flags = PATHSPEC_PREFER_FULL;
		struct strbuf buf = STRBUF_INIT;
		struct strbuf unquoted = STRBUF_INIT;

		if (patch_mode)
			die(_("--stdin is incompatible with --patch"));

		if (pathspec.nr)
			die(_("--stdin is incompatible with path arguments"));

		while (getline_fn(&buf, stdin) != EOF) {
			if (!nul_term_line && buf.buf[0] == '"') {
				strbuf_reset(&unquoted);
				if (unquote_c_style(&unquoted, buf.buf, NULL))
					die(_("line is badly quoted"));
				strbuf_swap(&buf, &unquoted);
			}
			ALLOC_GROW(stdin_paths, stdin_nr + 1, stdin_alloc);
			stdin_paths[stdin_nr++] = xstrdup(buf.buf);
			strbuf_reset(&buf);
		}
		strbuf_release(&unquoted);
		strbuf_release(&buf);

		ALLOC_GROW(stdin_paths, stdin_nr + 1, stdin_alloc);
		stdin_paths[stdin_nr++] = NULL;
		flags |= PATHSPEC_LITERAL_PATH;
		parse_pathspec(&pathspec, 0, flags, prefix,
			       (const char **)stdin_paths);

	} else if (nul_term_line)
		die(_("-z requires --stdin"));

	unborn = !strcmp(rev, "HEAD") && get_oid("HEAD", &oid);
	if (unborn) {
		/* reset on unborn branch: treat as reset to empty tree */
		hashcpy(oid.hash, EMPTY_TREE_SHA1_BIN);
	} else if (!pathspec.nr) {
		struct commit *commit;
		if (get_oid_committish(rev, &oid))
			die(_("Failed to resolve '%s' as a valid revision."), rev);
		commit = lookup_commit_reference(&oid);
		if (!commit)
			die(_("Could not parse object '%s'."), rev);
		oidcpy(&oid, &commit->object.oid);
	} else {
		struct tree *tree;
		if (get_oid_treeish(rev, &oid))
			die(_("Failed to resolve '%s' as a valid tree."), rev);
		tree = parse_tree_indirect(&oid);
		if (!tree)
			die(_("Could not parse object '%s'."), rev);
		oidcpy(&oid, &tree->object.oid);
	}

	if (patch_mode) {
		if (reset_type != NONE)
//.........这里部分代码省略.........

int cmd_add(int argc, const char **argv, const char *prefix)
{
	int exit_status = 0;
	struct pathspec pathspec;
	struct dir_struct dir;
	int flags;
	int add_new_files;
	int require_pathspec;
	char *seen = NULL;
	struct lock_file lock_file = LOCK_INIT;

	git_config(add_config, NULL);

	argc = parse_options(argc, argv, prefix, builtin_add_options,
			  builtin_add_usage, PARSE_OPT_KEEP_ARGV0);
	if (patch_interactive)
		add_interactive = 1;
	if (add_interactive)
		exit(interactive_add(argc - 1, argv + 1, prefix, patch_interactive));

	if (edit_interactive)
		return(edit_patch(argc, argv, prefix));
	argc--;
	argv++;

	if (0 <= addremove_explicit)
		addremove = addremove_explicit;
	else if (take_worktree_changes && ADDREMOVE_DEFAULT)
		addremove = 0; /* "-u" was given but not "-A" */

	if (addremove && take_worktree_changes)
		die(_("-A and -u are mutually incompatible"));

	if (!take_worktree_changes && addremove_explicit < 0 && argc)
		/* Turn "git add pathspec..." to "git add -A pathspec..." */
		addremove = 1;

	if (!show_only && ignore_missing)
		die(_("Option --ignore-missing can only be used together with --dry-run"));

	if (chmod_arg && ((chmod_arg[0] != '-' && chmod_arg[0] != '+') ||
			  chmod_arg[1] != 'x' || chmod_arg[2]))
		die(_("--chmod param '%s' must be either -x or +x"), chmod_arg);

	add_new_files = !take_worktree_changes && !refresh_only && !add_renormalize;
	require_pathspec = !(take_worktree_changes || (0 < addremove_explicit));

	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);

	flags = ((verbose ? ADD_CACHE_VERBOSE : 0) |
		 (show_only ? ADD_CACHE_PRETEND : 0) |
		 (intent_to_add ? ADD_CACHE_INTENT : 0) |
		 (ignore_add_errors ? ADD_CACHE_IGNORE_ERRORS : 0) |
		 (!(addremove || take_worktree_changes)
		  ? ADD_CACHE_IGNORE_REMOVAL : 0));

	if (require_pathspec && argc == 0) {
		fprintf(stderr, _("Nothing specified, nothing added.\n"));
		fprintf(stderr, _("Maybe you wanted to say 'git add .'?\n"));
		return 0;
	}

	/*
	 * Check the "pathspec '%s' did not match any files" block
	 * below before enabling new magic.
	 */
	parse_pathspec(&pathspec, PATHSPEC_ATTR,
		       PATHSPEC_PREFER_FULL |
		       PATHSPEC_SYMLINK_LEADING_PATH,
		       prefix, argv);

	if (read_cache_preload(&pathspec) < 0)
		die(_("index file corrupt"));

	die_in_unpopulated_submodule(&the_index, prefix);
	die_path_inside_submodule(&the_index, &pathspec);

	if (add_new_files) {
		int baselen;

		/* Set up the default git porcelain excludes */
		memset(&dir, 0, sizeof(dir));
		if (!ignored_too) {
			dir.flags |= DIR_COLLECT_IGNORED;
			setup_standard_excludes(&dir);
		}

		/* This picks up the paths that are not tracked */
		baselen = fill_directory(&dir, &the_index, &pathspec);
		if (pathspec.nr)
			seen = prune_directory(&dir, &pathspec, baselen);
	}

	if (refresh_only) {
		refresh(verbose, &pathspec);
		goto finish;
	}

	if (pathspec.nr) {
		int i;
//.........这里部分代码省略.........

int cmd_ls_tree(int argc, const char **argv, const char *prefix)
{
	unsigned char sha1[20];
	struct tree *tree;
	int i, full_tree = 0;
	const struct option ls_tree_options[] = {
		OPT_BIT('d', NULL, &ls_options, N_("only show trees"),
			LS_TREE_ONLY),
		OPT_BIT('r', NULL, &ls_options, N_("recurse into subtrees"),
			LS_RECURSIVE),
		OPT_BIT('t', NULL, &ls_options, N_("show trees when recursing"),
			LS_SHOW_TREES),
		OPT_SET_INT('z', NULL, &line_termination,
			    N_("terminate entries with NUL byte"), 0),
		OPT_BIT('l', "long", &ls_options, N_("include object size"),
			LS_SHOW_SIZE),
		OPT_BIT(0, "name-only", &ls_options, N_("list only filenames"),
			LS_NAME_ONLY),
		OPT_BIT(0, "name-status", &ls_options, N_("list only filenames"),
			LS_NAME_ONLY),
		OPT_SET_INT(0, "full-name", &chomp_prefix,
			    N_("use full path names"), 0),
		OPT_BOOL(0, "full-tree", &full_tree,
			 N_("list entire tree; not just current directory "
			    "(implies --full-name)")),
		OPT__ABBREV(&abbrev),
		OPT_END()
	};

	git_config(git_default_config, NULL);
	ls_tree_prefix = prefix;
	if (prefix && *prefix)
		chomp_prefix = strlen(prefix);

	argc = parse_options(argc, argv, prefix, ls_tree_options,
			     ls_tree_usage, 0);
	if (full_tree) {
		ls_tree_prefix = prefix = NULL;
		chomp_prefix = 0;
	}
	/* -d -r should imply -t, but -d by itself should not have to. */
	if ( (LS_TREE_ONLY|LS_RECURSIVE) ==
	    ((LS_TREE_ONLY|LS_RECURSIVE) & ls_options))
		ls_options |= LS_SHOW_TREES;

	if (argc < 1)
		usage_with_options(ls_tree_usage, ls_tree_options);
	if (get_sha1(argv[0], sha1))
		die("Not a valid object name %s", argv[0]);

	/*
	 * show_recursive() rolls its own matching code and is
	 * generally ignorant of 'struct pathspec'. The magic mask
	 * cannot be lifted until it is converted to use
	 * match_pathspec() or tree_entry_interesting()
	 */
	parse_pathspec(&pathspec, PATHSPEC_GLOB | PATHSPEC_ICASE |
				  PATHSPEC_EXCLUDE,
		       PATHSPEC_PREFER_CWD,
		       prefix, argv + 1);
	for (i = 0; i < pathspec.nr; i++)
		pathspec.items[i].nowildcard_len = pathspec.items[i].len;
	pathspec.has_wildcard = 0;
	tree = parse_tree_indirect(sha1);
	if (!tree)
		die("not a tree object");
	return !!read_tree_recursive(tree, "", 0, 0, &pathspec, show_tree, NULL);
}

static int phoenixfs_release(const char *path, struct fuse_file_info *fi)
{
	struct file_record *fr;
	FILE *infile, *outfile;
	struct stat st;
	unsigned char sha1[20];
	char sha1_digest[40];
	char outfilename[40];
	char inpath[PATH_MAX];
	char outpath[PATH_MAX];
	int rev, ret;

	pthread_mutex_lock(&phoenixfs_mutexlock);

	/* Don't recursively backup history */
	if ((rev = parse_pathspec(xpath, path))) {
		PHOENIXFS_DBG("release:: history: %s", path);

		/* Inflate the original version back onto the filesystem */
		if (!(fr = find_fr(xpath, 0))) {
			PHOENIXFS_DBG("release:: Can't find revision 0!");
			pthread_mutex_unlock(&phoenixfs_mutexlock);
			return 0;
		}
		print_sha1(sha1_digest, fr->sha1);
		sprintf(inpath, "%s/.git/loose/%s", ROOTENV->fsback, sha1_digest);
		build_xpath(outpath, xpath, 0);

		if (!(infile = fopen(inpath, "rb")) ||
			!(outfile = fopen(outpath, "wb+"))) {
			pthread_mutex_unlock(&phoenixfs_mutexlock);
			return -errno;
		}
		PHOENIXFS_DBG("release:: history: zinflate %s onto %s",
			sha1_digest, outpath);
		rewind(infile);
		rewind(outfile);
		if (zinflate(infile, outfile) != Z_OK)
			PHOENIXFS_DBG("release:: zinflate issue");
		fflush(outfile);
		fclose(infile);
		fclose(outfile);

		if (close(fi->fh) < 0) {
			PHOENIXFS_DBG("release:: can't really close");
			pthread_mutex_unlock(&phoenixfs_mutexlock);
			return -errno;
		}
		pthread_mutex_unlock(&phoenixfs_mutexlock);
		return 0;
	}

	/* Attempt to create a backup */
	build_xpath(xpath, path, 0);
	if (!(infile = fopen(xpath, "rb")) ||
		(lstat(xpath, &st) < 0)) {
		pthread_mutex_unlock(&phoenixfs_mutexlock);
		return -errno;
	}
	if ((ret = sha1_file(infile, st.st_size, sha1)) < 0) {
		fclose(infile);
		pthread_mutex_unlock(&phoenixfs_mutexlock);
		return ret;
	}
	print_sha1(outfilename, sha1);
	sprintf(outpath, "%s/.git/loose/%s", ROOTENV->fsback, outfilename);
	if (!access(outpath, F_OK)) {
		/* SHA1 match; don't overwrite file as an optimization */
		PHOENIXFS_DBG("release:: not overwriting: %s", outpath);
		goto END;
	}
	if (!(outfile = fopen(outpath, "wb"))) {
		fclose(infile);
		pthread_mutex_unlock(&phoenixfs_mutexlock);
		return -errno;
	}

	/* Rewind and seek back */
	rewind(infile);
	PHOENIXFS_DBG("release:: zdeflate %s onto %s", xpath, outfilename);
	if (zdeflate(infile, outfile, -1) != Z_OK)
		PHOENIXFS_DBG("release:: zdeflate issue");
	mark_for_packing(sha1, st.st_size);
	fclose(outfile);
END:
	fclose(infile);
	if (close(fi->fh) < 0) {
		PHOENIXFS_DBG("release:: can't really close");
		return -errno;
	}

	/* Update the fstree */
	fstree_insert_update_file(path, NULL);

	pthread_mutex_unlock(&phoenixfs_mutexlock);
	return 0;
}

/*
 * We have an origin -- check if the same path exists in the
 * parent and return an origin structure to represent it.
 */
static struct blame_origin *find_origin(struct commit *parent,
				  struct blame_origin *origin)
{
	struct blame_origin *porigin;
	struct diff_options diff_opts;
	const char *paths[2];

	/* First check any existing origins */
	for (porigin = parent->util; porigin; porigin = porigin->next)
		if (!strcmp(porigin->path, origin->path)) {
			/*
			 * The same path between origin and its parent
			 * without renaming -- the most common case.
			 */
			return blame_origin_incref (porigin);
		}

	/* See if the origin->path is different between parent
	 * and origin first.  Most of the time they are the
	 * same and diff-tree is fairly efficient about this.
	 */
	diff_setup(&diff_opts);
	DIFF_OPT_SET(&diff_opts, RECURSIVE);
	diff_opts.detect_rename = 0;
	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
	paths[0] = origin->path;
	paths[1] = NULL;

	parse_pathspec(&diff_opts.pathspec,
		       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
		       PATHSPEC_LITERAL_PATH, "", paths);
	diff_setup_done(&diff_opts);

	if (is_null_oid(&origin->commit->object.oid))
		do_diff_cache(&parent->tree->object.oid, &diff_opts);
	else
		diff_tree_oid(&parent->tree->object.oid,
			      &origin->commit->tree->object.oid,
			      "", &diff_opts);
	diffcore_std(&diff_opts);

	if (!diff_queued_diff.nr) {
		/* The path is the same as parent */
		porigin = get_origin(parent, origin->path);
		oidcpy(&porigin->blob_oid, &origin->blob_oid);
		porigin->mode = origin->mode;
	} else {
		/*
		 * Since origin->path is a pathspec, if the parent
		 * commit had it as a directory, we will see a whole
		 * bunch of deletion of files in the directory that we
		 * do not care about.
		 */
		int i;
		struct diff_filepair *p = NULL;
		for (i = 0; i < diff_queued_diff.nr; i++) {
			const char *name;
			p = diff_queued_diff.queue[i];
			name = p->one->path ? p->one->path : p->two->path;
			if (!strcmp(name, origin->path))
				break;
		}
		if (!p)
			die("internal error in blame::find_origin");
		switch (p->status) {
		default:
			die("internal error in blame::find_origin (%c)",
			    p->status);
		case 'M':
			porigin = get_origin(parent, origin->path);
			oidcpy(&porigin->blob_oid, &p->one->oid);
			porigin->mode = p->one->mode;
			break;
		case 'A':
		case 'T':
			/* Did not exist in parent, or type changed */
			break;
		}
	}
	diff_flush(&diff_opts);
	clear_pathspec(&diff_opts.pathspec);
	return porigin;
}

static void try_to_follow_renames(const struct object_id *old_oid,
				  const struct object_id *new_oid,
				  struct strbuf *base, struct diff_options *opt)
{
	struct diff_options diff_opts;
	struct diff_queue_struct *q = &diff_queued_diff;
	struct diff_filepair *choice;
	int i;

	/*
	 * follow-rename code is very specific, we need exactly one
	 * path. Magic that matches more than one path is not
	 * supported.
	 */
	GUARD_PATHSPEC(&opt->pathspec, PATHSPEC_FROMTOP | PATHSPEC_LITERAL);
#if 0
	/*
	 * We should reject wildcards as well. Unfortunately we
	 * haven't got a reliable way to detect that 'foo\*bar' in
	 * fact has no wildcards. nowildcard_len is merely a hint for
	 * optimization. Let it slip for now until wildmatch is taught
	 * about dry-run mode and returns wildcard info.
	 */
	if (opt->pathspec.has_wildcard)
		die("BUG:%s:%d: wildcards are not supported",
		    __FILE__, __LINE__);
#endif

	/* Remove the file creation entry from the diff queue, and remember it */
	choice = q->queue[0];
	q->nr = 0;

	diff_setup(&diff_opts);
	diff_opts.flags.recursive = 1;
	diff_opts.flags.find_copies_harder = 1;
	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
	diff_opts.single_follow = opt->pathspec.items[0].match;
	diff_opts.break_opt = opt->break_opt;
	diff_opts.rename_score = opt->rename_score;
	diff_setup_done(&diff_opts);
	ll_diff_tree_oid(old_oid, new_oid, base, &diff_opts);
	diffcore_std(&diff_opts);
	clear_pathspec(&diff_opts.pathspec);

	/* Go through the new set of filepairing, and see if we find a more interesting one */
	opt->found_follow = 0;
	for (i = 0; i < q->nr; i++) {
		struct diff_filepair *p = q->queue[i];

		/*
		 * Found a source? Not only do we use that for the new
		 * diff_queued_diff, we will also use that as the path in
		 * the future!
		 */
		if ((p->status == 'R' || p->status == 'C') &&
		    !strcmp(p->two->path, opt->pathspec.items[0].match)) {
			const char *path[2];

			/* Switch the file-pairs around */
			q->queue[i] = choice;
			choice = p;

			/* Update the path we use from now on.. */
			path[0] = p->one->path;
			path[1] = NULL;
			clear_pathspec(&opt->pathspec);
			parse_pathspec(&opt->pathspec,
				       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
				       PATHSPEC_LITERAL_PATH, "", path);

			/*
			 * The caller expects us to return a set of vanilla
			 * filepairs to let a later call to diffcore_std()
			 * it makes to sort the renames out (among other
			 * things), but we already have found renames
			 * ourselves; signal diffcore_std() not to muck with
			 * rename information.
			 */
			opt->found_follow = 1;
			break;
		}
	}

	/*
	 * Then, discard all the non-relevant file pairs...
	 */
	for (i = 0; i < q->nr; i++) {
		struct diff_filepair *p = q->queue[i];
		diff_free_filepair(p);
	}

	/*
	 * .. and re-instate the one we want (which might be either the
	 * original one, or the rename/copy we found)
	 */
	q->queue[0] = choice;
	q->nr = 1;
}